diff --git a/gdb/aarch64-fbsd-tdep.c b/gdb/aarch64-fbsd-tdep.c
index 3f22d41..7342e7b 100644
--- a/gdb/aarch64-fbsd-tdep.c
+++ b/gdb/aarch64-fbsd-tdep.c
@@ -153,7 +153,7 @@ aarch64_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 static void
 aarch64_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Generic FreeBSD support.  */
   fbsd_init_abi (info, gdbarch);
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index abb8be3..7a9cf0c 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -286,7 +286,7 @@ aarch64_linux_sigframe_init (const struct tramp_frame *self,
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR sp = get_frame_register_unsigned (this_frame, AARCH64_SP_REGNUM);
   CORE_ADDR sigcontext_addr = (sp + AARCH64_RT_SIGFRAME_UCONTEXT_OFFSET
 			       + AARCH64_UCONTEXT_SIGCONTEXT_OFFSET );
@@ -640,7 +640,8 @@ aarch64_linux_collect_sve_regset (const struct regset *regset,
   gdb_byte *header = (gdb_byte *) buf;
   struct gdbarch *gdbarch = regcache->arch ();
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  uint64_t vq = gdbarch_tdep (gdbarch)->vq;
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  uint64_t vq = tdep->vq;
 
   gdb_assert (buf != NULL);
   gdb_assert (size > SVE_HEADER_SIZE);
@@ -675,7 +676,7 @@ aarch64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					    void *cb_data,
 					    const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", AARCH64_LINUX_SIZEOF_GREGSET, AARCH64_LINUX_SIZEOF_GREGSET,
       &aarch64_linux_gregset, NULL, cb_data);
@@ -1719,7 +1720,7 @@ aarch64_linux_report_signal_info (struct gdbarch *gdbarch,
 				  struct ui_out *uiout,
 				  enum gdb_signal siggnal)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->has_mte () || siggnal != GDB_SIGNAL_SEGV)
     return;
@@ -1788,7 +1789,7 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 								    NULL };
   static const char *const stap_register_indirection_suffixes[] = { "]",
 								    NULL };
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->lowest_pc = 0x8000;
 
diff --git a/gdb/aarch64-newlib-tdep.c b/gdb/aarch64-newlib-tdep.c
index b5e57bc..9805967 100644
--- a/gdb/aarch64-newlib-tdep.c
+++ b/gdb/aarch64-newlib-tdep.c
@@ -29,7 +29,7 @@
 static void
 aarch64_newlib_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Jump buffer - support for longjmp.
      Offset of original PC in jump buffer (in registers).  */
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 42b8494..392110a 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -248,7 +248,7 @@ class instruction_reader : public abstract_instruction_reader
    THIS_FRAME.  */
 
 static CORE_ADDR
-aarch64_frame_unmask_lr (struct gdbarch_tdep *tdep,
+aarch64_frame_unmask_lr (aarch64_gdbarch_tdep *tdep,
 			 struct frame_info *this_frame, CORE_ADDR addr)
 {
   if (tdep->has_pauth ()
@@ -500,7 +500,8 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 	}
       else if (inst.opcode->iclass == ic_system)
 	{
-	  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+	  aarch64_gdbarch_tdep *tdep
+	    = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 	  int ra_state_val = 0;
 
 	  if (insn == 0xd503233f /* paciasp.  */
@@ -635,7 +636,7 @@ aarch64_analyze_prologue_test (void)
   struct aarch64_prologue_cache cache;
   cache.saved_regs = trad_frame_alloc_saved_regs (gdbarch);
 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Test the simple prologue in which frame pointer is used.  */
   {
@@ -1037,7 +1038,9 @@ aarch64_prologue_frame_unwind_stop_reason (struct frame_info *this_frame,
     return UNWIND_UNAVAILABLE;
 
   /* Halt the backtrace at "_start".  */
-  if (cache->prev_pc <= gdbarch_tdep (get_frame_arch (this_frame))->lowest_pc)
+  gdbarch *arch = get_frame_arch (this_frame);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (arch);
+  if (cache->prev_pc <= tdep->lowest_pc)
     return UNWIND_OUTERMOST;
 
   /* We've hit a wall, stop.  */
@@ -1079,7 +1082,8 @@ aarch64_prologue_prev_register (struct frame_info *this_frame,
     {
       CORE_ADDR lr;
       struct gdbarch *gdbarch = get_frame_arch (this_frame);
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      aarch64_gdbarch_tdep *tdep
+	= (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
       lr = frame_unwind_register_unsigned (this_frame, AARCH64_LR_REGNUM);
 
@@ -1247,7 +1251,8 @@ static struct value *
 aarch64_dwarf2_prev_register (struct frame_info *this_frame,
 			      void **this_cache, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (arch);
   CORE_ADDR lr;
 
   switch (regnum)
@@ -1273,7 +1278,7 @@ aarch64_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
 			       struct dwarf2_frame_state_reg *reg,
 			       struct frame_info *this_frame)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   switch (regnum)
     {
@@ -1313,7 +1318,7 @@ static bool
 aarch64_execute_dwarf_cfa_vendor_op (struct gdbarch *gdbarch, gdb_byte op,
 				     struct dwarf2_frame_state *fs)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct dwarf2_frame_state_reg *ra_state;
 
   if (op == DW_CFA_AARCH64_negate_ra_state)
@@ -1952,7 +1957,7 @@ aarch64_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
 static struct type *
 aarch64_vnq_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->vnq_type == NULL)
     {
@@ -1979,7 +1984,7 @@ aarch64_vnq_type (struct gdbarch *gdbarch)
 static struct type *
 aarch64_vnd_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->vnd_type == NULL)
     {
@@ -2009,7 +2014,7 @@ aarch64_vnd_type (struct gdbarch *gdbarch)
 static struct type *
 aarch64_vns_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->vns_type == NULL)
     {
@@ -2039,7 +2044,7 @@ aarch64_vns_type (struct gdbarch *gdbarch)
 static struct type *
 aarch64_vnh_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->vnh_type == NULL)
     {
@@ -2072,7 +2077,7 @@ aarch64_vnh_type (struct gdbarch *gdbarch)
 static struct type *
 aarch64_vnb_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->vnb_type == NULL)
     {
@@ -2099,7 +2104,7 @@ aarch64_vnb_type (struct gdbarch *gdbarch)
 static struct type *
 aarch64_vnv_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->vnv_type == NULL)
     {
@@ -2170,7 +2175,7 @@ aarch64_vnv_type (struct gdbarch *gdbarch)
 static int
 aarch64_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (reg >= AARCH64_DWARF_X0 && reg <= AARCH64_DWARF_X0 + 30)
     return AARCH64_X0_REGNUM + reg - AARCH64_DWARF_X0;
@@ -2457,7 +2462,7 @@ aarch64_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
   CORE_ADDR jb_addr;
   gdb_byte buf[X_REGISTER_SIZE];
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   jb_addr = get_frame_register_unsigned (frame, AARCH64_X0_REGNUM);
@@ -2488,7 +2493,7 @@ aarch64_gen_return_address (struct gdbarch *gdbarch,
 static const char *
 aarch64_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   static const char *const q_name[] =
     {
@@ -2602,7 +2607,7 @@ aarch64_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 static struct type *
 aarch64_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   int p_regnum = regnum - gdbarch_num_regs (gdbarch);
 
@@ -2639,7 +2644,7 @@ static int
 aarch64_pseudo_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 				    struct reggroup *group)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   int p_regnum = regnum - gdbarch_num_regs (gdbarch);
 
@@ -2693,7 +2698,7 @@ static struct value *
 aarch64_pseudo_read_value (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct value *result_value = allocate_value (register_type (gdbarch, regnum));
 
   VALUE_LVAL (result_value) = lval_register;
@@ -2763,7 +2768,7 @@ static void
 aarch64_pseudo_write (struct gdbarch *gdbarch, struct regcache *regcache,
 		      int regnum, const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   regnum -= gdbarch_num_regs (gdbarch);
 
   if (regnum >= AARCH64_Q0_REGNUM && regnum < AARCH64_Q0_REGNUM + 32)
@@ -3328,7 +3333,7 @@ aarch64_add_reggroups (struct gdbarch *gdbarch)
 static int
 aarch64_cannot_store_register (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->has_pauth ())
     return 0;
@@ -3375,7 +3380,8 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch != nullptr;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
-      struct gdbarch_tdep *tdep = gdbarch_tdep (best_arch->gdbarch);
+      aarch64_gdbarch_tdep *tdep
+	= (aarch64_gdbarch_tdep *) gdbarch_tdep (best_arch->gdbarch);
       if (tdep && tdep->vq == vq)
 	return best_arch->gdbarch;
     }
@@ -3483,7 +3489,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* AArch64 code is always little-endian.  */
   info.byte_order_for_code = BFD_ENDIAN_LITTLE;
 
-  struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
+  aarch64_gdbarch_tdep *tdep = new aarch64_gdbarch_tdep;
   struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
 
   /* This should be low enough for everything.  */
@@ -3605,7 +3611,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 aarch64_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  aarch64_gdbarch_tdep *tdep = (aarch64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep == NULL)
     return;
@@ -3825,7 +3831,9 @@ aarch64_record_data_proc_imm (insn_decode_record *aarch64_insn_r)
 static unsigned int
 aarch64_record_branch_except_sys (insn_decode_record *aarch64_insn_r)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (aarch64_insn_r->gdbarch);
+
+  aarch64_gdbarch_tdep *tdep
+    = (aarch64_gdbarch_tdep *) gdbarch_tdep (aarch64_insn_r->gdbarch);
   uint8_t insn_bits24_27, insn_bits28_31, insn_bits22_23;
   uint32_t record_buf[4];
 
diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
index 7bf612b..efb0fa2 100644
--- a/gdb/aarch64-tdep.h
+++ b/gdb/aarch64-tdep.h
@@ -25,6 +25,7 @@
 #include "arch/aarch64.h"
 #include "displaced-stepping.h"
 #include "infrun.h"
+#include "gdbarch.h"
 
 /* Forward declarations.  */
 struct gdbarch;
@@ -60,31 +61,32 @@ struct regset;
 #define AARCH64_DISPLACED_MODIFIED_INSNS 1
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct aarch64_gdbarch_tdep : gdbarch_tdep
 {
   /* Lowest address at which instructions will appear.  */
-  CORE_ADDR lowest_pc;
+  CORE_ADDR lowest_pc = 0;
 
   /* Offset to PC value in jump buffer.  If this is negative, longjmp
      support will be disabled.  */
-  int jb_pc;
+  int jb_pc = 0;
 
   /* And the size of each entry in the buf.  */
-  size_t jb_elt_size;
+  size_t jb_elt_size = 0;
 
   /* Types for AdvSISD registers.  */
-  struct type *vnq_type;
-  struct type *vnd_type;
-  struct type *vns_type;
-  struct type *vnh_type;
-  struct type *vnb_type;
-  struct type *vnv_type;
+  struct type *vnq_type = nullptr;
+  struct type *vnd_type = nullptr;
+  struct type *vns_type = nullptr;
+  struct type *vnh_type = nullptr;
+  struct type *vnb_type = nullptr;
+  struct type *vnv_type = nullptr;
 
   /* syscall record.  */
-  int (*aarch64_syscall_record) (struct regcache *regcache, unsigned long svc_number);
+  int (*aarch64_syscall_record) (struct regcache *regcache,
+				 unsigned long svc_number) = nullptr;
 
   /* The VQ value for SVE targets, or zero if SVE is not supported.  */
-  uint64_t vq;
+  uint64_t vq = 0;
 
   /* Returns true if the target supports SVE.  */
   bool has_sve () const
@@ -92,8 +94,8 @@ struct gdbarch_tdep
     return vq != 0;
   }
 
-  int pauth_reg_base;
-  int pauth_ra_state_regnum;
+  int pauth_reg_base = 0;
+  int pauth_ra_state_regnum = 0;
 
   /* Returns true if the target supports pauth.  */
   bool has_pauth () const
@@ -102,7 +104,7 @@ struct gdbarch_tdep
   }
 
   /* First MTE register.  This is -1 if no MTE registers are available.  */
-  int mte_reg_base;
+  int mte_reg_base = 0;
 
   /* Returns true if the target supports MTE.  */
   bool has_mte () const
diff --git a/gdb/alpha-linux-tdep.c b/gdb/alpha-linux-tdep.c
index 0a00fc1..b821a6b 100644
--- a/gdb/alpha-linux-tdep.c
+++ b/gdb/alpha-linux-tdep.c
@@ -354,8 +354,6 @@ alpha_linux_gdb_signal_to_target (struct gdbarch *gdbarch,
 static void
 alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep;
-
   linux_init_abi (info, gdbarch, 0);
 
   /* Hook into the DWARF CFI frame unwinder.  */
@@ -364,7 +362,7 @@ alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   /* Hook into the MDEBUG frame unwinder.  */
   alpha_mdebug_init_abi (info, gdbarch);
 
-  tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset;
   tdep->sigcontext_addr = alpha_linux_sigcontext_addr;
   tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp;
diff --git a/gdb/alpha-netbsd-tdep.c b/gdb/alpha-netbsd-tdep.c
index 0b03aa1..b19f76b 100644
--- a/gdb/alpha-netbsd-tdep.c
+++ b/gdb/alpha-netbsd-tdep.c
@@ -250,7 +250,7 @@ static void
 alphanbsd_init_abi (struct gdbarch_info info,
 		    struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Hook into the DWARF CFI frame unwinder.  */
   alpha_dwarf2_init_abi (info, gdbarch);
diff --git a/gdb/alpha-obsd-tdep.c b/gdb/alpha-obsd-tdep.c
index 0afd4dc..7ca5ca1 100644
--- a/gdb/alpha-obsd-tdep.c
+++ b/gdb/alpha-obsd-tdep.c
@@ -97,7 +97,7 @@ alphaobsd_sigcontext_addr (struct frame_info *this_frame)
 static void
 alphaobsd_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Hook into the DWARF CFI frame unwinder.  */
   alpha_dwarf2_init_abi (info, gdbarch);
diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c
index 03935d1..760a18a 100644
--- a/gdb/alpha-tdep.c
+++ b/gdb/alpha-tdep.c
@@ -615,11 +615,12 @@ alpha_return_value (struct gdbarch *gdbarch, struct value *function,
 		    gdb_byte *readbuf, const gdb_byte *writebuf)
 {
   enum type_code code = type->code ();
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if ((code == TYPE_CODE_STRUCT
        || code == TYPE_CODE_UNION
        || code == TYPE_CODE_ARRAY)
-      && gdbarch_tdep (gdbarch)->return_in_memory (type))
+      && tdep->return_in_memory (type))
     {
       if (readbuf)
 	{
@@ -850,7 +851,7 @@ static int
 alpha_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR jb_addr;
   gdb_byte raw_buffer[ALPHA_REGISTER_SIZE];
@@ -882,7 +883,6 @@ alpha_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
 				   void **this_prologue_cache)
 {
   struct alpha_sigtramp_unwind_cache *info;
-  struct gdbarch_tdep *tdep;
 
   if (*this_prologue_cache)
     return (struct alpha_sigtramp_unwind_cache *) *this_prologue_cache;
@@ -890,7 +890,8 @@ alpha_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
   info = FRAME_OBSTACK_ZALLOC (struct alpha_sigtramp_unwind_cache);
   *this_prologue_cache = info;
 
-  tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (arch);
   info->sigcontext_addr = tdep->sigcontext_addr (this_frame);
 
   return info;
@@ -903,7 +904,7 @@ static CORE_ADDR
 alpha_sigtramp_register_address (struct gdbarch *gdbarch,
 				 CORE_ADDR sigcontext_addr, int regnum)
 { 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (regnum >= 0 && regnum < 32)
     return sigcontext_addr + tdep->sc_regs_offset + regnum * 8;
@@ -924,7 +925,7 @@ alpha_sigtramp_frame_this_id (struct frame_info *this_frame,
 			      struct frame_id *this_id)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct alpha_sigtramp_unwind_cache *info
     = alpha_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
   CORE_ADDR stack_addr, code_addr;
@@ -999,14 +1000,16 @@ alpha_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
   /* We shouldn't even bother to try if the OSABI didn't register a
      sigcontext_addr handler or pc_in_sigtramp handler.  */
-  if (gdbarch_tdep (gdbarch)->sigcontext_addr == NULL)
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->sigcontext_addr == NULL)
     return 0;
-  if (gdbarch_tdep (gdbarch)->pc_in_sigtramp == NULL)
+
+  if (tdep->pc_in_sigtramp == NULL)
     return 0;
 
   /* Otherwise we should be in a signal frame.  */
   find_pc_partial_function (pc, &name, NULL, NULL);
-  if (gdbarch_tdep (gdbarch)->pc_in_sigtramp (gdbarch, pc, name))
+  if (tdep->pc_in_sigtramp (gdbarch, pc, name))
     return 1;
 
   return 0;
@@ -1038,7 +1041,7 @@ static int heuristic_fence_post = 0;
 static CORE_ADDR
 alpha_heuristic_proc_start (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR last_non_nop = pc;
   CORE_ADDR fence = pc - heuristic_fence_post;
   CORE_ADDR orig_pc = pc;
@@ -1724,7 +1727,6 @@ alpha_software_single_step (struct regcache *regcache)
 static struct gdbarch *
 alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
 
   /* Find a candidate among extant architectures.  */
@@ -1732,7 +1734,7 @@ alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   if (arches != NULL)
     return arches->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  alpha_gdbarch_tdep *tdep = new alpha_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Lowest text address.  This is used by heuristic_proc_start()
diff --git a/gdb/alpha-tdep.h b/gdb/alpha-tdep.h
index c1fd694..c1674fe 100644
--- a/gdb/alpha-tdep.h
+++ b/gdb/alpha-tdep.h
@@ -19,6 +19,8 @@
 #ifndef ALPHA_TDEP_H
 #define ALPHA_TDEP_H
 
+#include "gdbarch.h"
+
 struct regcache;
 
 /* Say how long (ordinary) registers are.  This is a piece of bogosity
@@ -68,38 +70,38 @@ struct regcache;
 #define ALPHA_NUM_ARG_REGS   6
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct alpha_gdbarch_tdep : gdbarch_tdep
 {
-  CORE_ADDR vm_min_address;	/* Used by alpha_heuristic_proc_start.  */
+  CORE_ADDR vm_min_address = 0;	/* Used by alpha_heuristic_proc_start.  */
 
   /* If PC is inside a dynamically-generated signal trampoline function
      (i.e. one copied onto the user stack at run-time), return how many
      bytes PC is beyond the start of that function.  Otherwise, return -1.  */
-  LONGEST (*dynamic_sigtramp_offset) (struct gdbarch *, CORE_ADDR);
+  LONGEST (*dynamic_sigtramp_offset) (struct gdbarch *, CORE_ADDR) = nullptr;
 
   /* Translate a signal handler stack base address into the address of
      the sigcontext structure for that signal handler.  */
-  CORE_ADDR (*sigcontext_addr) (struct frame_info *);
+  CORE_ADDR (*sigcontext_addr) (struct frame_info *) = nullptr;
 
   /* Does the PC fall in a signal trampoline.  */
   /* NOTE: cagney/2004-04-30: Do not copy/clone this code.  Instead
      look at tramp-frame.h and other simpler per-architecture
      sigtramp unwinders.  */
   int (*pc_in_sigtramp) (struct gdbarch *gdbarch, CORE_ADDR pc,
-			 const char *name);
+			 const char *name) = nullptr;
 
   /* If TYPE will be returned in memory, return true.  */
-  int (*return_in_memory) (struct type *type);
+  int (*return_in_memory) (struct type *type) = nullptr;
 
   /* Offset of registers in `struct sigcontext'.  */
-  int sc_pc_offset;
-  int sc_regs_offset;
-  int sc_fpregs_offset;
+  int sc_pc_offset = 0;
+  int sc_regs_offset = 0;
+  int sc_fpregs_offset = 0;
 
-  int jb_pc;			/* Offset to PC value in jump buffer.
+  int jb_pc = 0;			/* Offset to PC value in jump buffer.
 				   If htis is negative, longjmp support
 				   will be disabled.  */
-  size_t jb_elt_size;		/* And the size of each entry in the buf.  */
+  size_t jb_elt_size = 0;		/* And the size of each entry in the buf.  */
 };
 
 extern unsigned int alpha_read_insn (struct gdbarch *gdbarch, CORE_ADDR pc);
diff --git a/gdb/amd64-darwin-tdep.c b/gdb/amd64-darwin-tdep.c
index 3bd6296..5cf3ff2 100644
--- a/gdb/amd64-darwin-tdep.c
+++ b/gdb/amd64-darwin-tdep.c
@@ -97,7 +97,7 @@ amd64_darwin_sigcontext_addr (struct frame_info *this_frame)
 static void
 x86_darwin_init_abi_64 (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   amd64_init_abi (info, gdbarch,
 		  amd64_target_description (X86_XSTATE_SSE_MASK, true));
diff --git a/gdb/amd64-fbsd-tdep.c b/gdb/amd64-fbsd-tdep.c
index 2894313..5069342 100644
--- a/gdb/amd64-fbsd-tdep.c
+++ b/gdb/amd64-fbsd-tdep.c
@@ -195,7 +195,7 @@ amd64fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					void *cb_data,
 					const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", tdep->sizeof_gregset, tdep->sizeof_gregset, &i386_gregset, NULL,
       cb_data);
@@ -229,7 +229,7 @@ amd64fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 static void
 amd64fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Generic FreeBSD support. */
   fbsd_init_abi (info, gdbarch);
diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c
index 715add8..817a197 100644
--- a/gdb/amd64-linux-tdep.c
+++ b/gdb/amd64-linux-tdep.c
@@ -1650,7 +1650,7 @@ amd64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					  void *cb_data,
 					  const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", 27 * 8, 27 * 8, &i386_gregset, NULL, cb_data);
   cb (".reg2", 512, 512, &amd64_fpregset, NULL, cb_data);
@@ -1787,7 +1787,7 @@ static void
 amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch,
 			    int num_disp_step_buffers)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, num_disp_step_buffers);
 
@@ -1840,7 +1840,7 @@ amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch,
 static void
 amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct tdesc_arch_data *tdesc_data = info.tdesc_data;
   const struct tdesc_feature *feature;
   int valid_p;
@@ -2054,7 +2054,7 @@ amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 static void
 amd64_x32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct tdesc_arch_data *tdesc_data = info.tdesc_data;
   const struct tdesc_feature *feature;
   int valid_p;
diff --git a/gdb/amd64-netbsd-tdep.c b/gdb/amd64-netbsd-tdep.c
index 439dd91..be8ee37 100644
--- a/gdb/amd64-netbsd-tdep.c
+++ b/gdb/amd64-netbsd-tdep.c
@@ -97,7 +97,7 @@ int amd64nbsd_r_reg_offset[] =
 static void
 amd64nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Initialize general-purpose register set details first.  */
   tdep->gregset_reg_offset = amd64nbsd_r_reg_offset;
diff --git a/gdb/amd64-obsd-tdep.c b/gdb/amd64-obsd-tdep.c
index 070f196..0da1dbf 100644
--- a/gdb/amd64-obsd-tdep.c
+++ b/gdb/amd64-obsd-tdep.c
@@ -420,7 +420,7 @@ static const struct frame_unwind amd64obsd_trapframe_unwind =
 static void
 amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   amd64_init_abi (info, gdbarch,
 		  amd64_target_description (X86_XSTATE_SSE_MASK, true));
diff --git a/gdb/amd64-sol2-tdep.c b/gdb/amd64-sol2-tdep.c
index e561c0d..4cb243b 100644
--- a/gdb/amd64-sol2-tdep.c
+++ b/gdb/amd64-sol2-tdep.c
@@ -80,7 +80,7 @@ amd64_sol2_mcontext_addr (struct frame_info *this_frame)
 static void
 amd64_sol2_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->gregset_reg_offset = amd64_sol2_gregset_reg_offset;
   tdep->gregset_num_regs = ARRAY_SIZE (amd64_sol2_gregset_reg_offset);
diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index de04bbd..7c67359 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -247,7 +247,7 @@ static const int amd64_dwarf_regmap_len =
 static int
 amd64_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ymm0_regnum = tdep->ymm0_regnum;
   int regnum = -1;
 
@@ -331,7 +331,7 @@ static const char * const amd64_dword_names[] =
 static const char *
 amd64_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (i386_byte_regnum_p (gdbarch, regnum))
     return amd64_byte_names[regnum - tdep->al_regnum];
   else if (i386_zmm_regnum_p (gdbarch, regnum))
@@ -353,7 +353,7 @@ amd64_pseudo_register_read_value (struct gdbarch *gdbarch,
 				  readable_regcache *regcache,
 				  int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   value *result_value = allocate_value (register_type (gdbarch, regnum));
   VALUE_LVAL (result_value) = lval_register;
@@ -413,7 +413,7 @@ amd64_pseudo_register_write (struct gdbarch *gdbarch,
 			     struct regcache *regcache,
 			     int regnum, const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (i386_byte_regnum_p (gdbarch, regnum))
     {
@@ -465,7 +465,7 @@ static int
 amd64_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				  struct agent_expr *ax, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (i386_byte_regnum_p (gdbarch, regnum))
     {
@@ -2739,7 +2739,7 @@ static struct amd64_frame_cache *
 amd64_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct amd64_frame_cache *cache;
   CORE_ADDR addr;
@@ -2821,7 +2821,8 @@ amd64_sigtramp_frame_sniffer (const struct frame_unwind *self,
 			      struct frame_info *this_frame,
 			      void **this_cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* We shouldn't even bother if we don't have a sigcontext_addr
      handler.  */
@@ -3021,7 +3022,7 @@ amd64_supply_fpregset (const struct regset *regset, struct regcache *regcache,
 		       int regnum, const void *fpregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (len >= tdep->sizeof_fpregset);
   amd64_supply_fxsave (regcache, regnum, fpregs);
@@ -3038,7 +3039,7 @@ amd64_collect_fpregset (const struct regset *regset,
 			int regnum, void *fpregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (len >= tdep->sizeof_fpregset);
   amd64_collect_fxsave (regcache, regnum, fpregs);
@@ -3062,7 +3063,8 @@ amd64_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
   gdb_byte buf[8];
   CORE_ADDR jb_addr;
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  int jb_pc_offset = gdbarch_tdep (gdbarch)->jb_pc_offset;
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int jb_pc_offset = tdep->jb_pc_offset;
   int len = TYPE_LENGTH (builtin_type (gdbarch)->builtin_func_ptr);
 
   /* If JB_PC_OFFSET is -1, we have no way to find out where the
@@ -3105,7 +3107,7 @@ void
 amd64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch,
 		const target_desc *default_tdesc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const struct target_desc *tdesc = info.target_desc;
   static const char *const stap_integer_prefixes[] = { "$", NULL };
   static const char *const stap_register_prefixes[] = { "%", NULL };
@@ -3284,7 +3286,7 @@ amd64_none_init_abi (gdbarch_info info, gdbarch *arch)
 static struct type *
 amd64_x32_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   switch (regnum - tdep->eax_regnum)
     {
@@ -3302,7 +3304,7 @@ void
 amd64_x32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch,
 		    const target_desc *default_tdesc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   amd64_init_abi (info, gdbarch, default_tdesc);
 
@@ -3372,7 +3374,7 @@ amd64_supply_fxsave (struct regcache *regcache, int regnum,
 		     const void *fxsave)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   i387_supply_fxsave (regcache, regnum, fxsave);
 
@@ -3395,7 +3397,7 @@ amd64_supply_xsave (struct regcache *regcache, int regnum,
 		    const void *xsave)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   i387_supply_xsave (regcache, regnum, xsave);
 
@@ -3430,7 +3432,7 @@ amd64_collect_fxsave (const struct regcache *regcache, int regnum,
 		      void *fxsave)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_byte *regs = (gdb_byte *) fxsave;
 
   i387_collect_fxsave (regcache, regnum, fxsave);
@@ -3451,7 +3453,7 @@ amd64_collect_xsave (const struct regcache *regcache, int regnum,
 		     void *xsave, int gcore)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_byte *regs = (gdb_byte *) xsave;
 
   i387_collect_xsave (regcache, regnum, xsave, gcore);
diff --git a/gdb/amd64-windows-tdep.c b/gdb/amd64-windows-tdep.c
index ed783f6..fb3fe48 100644
--- a/gdb/amd64-windows-tdep.c
+++ b/gdb/amd64-windows-tdep.c
@@ -1277,7 +1277,7 @@ amd64_windows_auto_wide_charset (void)
 static void
 amd64_windows_init_abi_common (gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* The dwarf2 unwinder (appended very early by i386_gdbarch_init) is
      preferred over the SEH one.  The reasons are:
diff --git a/gdb/arc-linux-tdep.c b/gdb/arc-linux-tdep.c
index 448fa37..de95d5a 100644
--- a/gdb/arc-linux-tdep.c
+++ b/gdb/arc-linux-tdep.c
@@ -410,7 +410,7 @@ static std::vector<CORE_ADDR>
 arc_linux_software_single_step (struct regcache *regcache)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arc_gdbarch_tdep *tdep = (arc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct disassemble_info di = arc_disassemble_info (gdbarch);
 
   /* Read current instruction.  */
@@ -692,7 +692,7 @@ arc_linux_core_read_description (struct gdbarch *gdbarch,
 static void
 arc_linux_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arc_gdbarch_tdep *tdep = (arc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   arc_linux_debug_printf ("GNU/Linux OS/ABI initialization.");
 
diff --git a/gdb/arc-tdep.c b/gdb/arc-tdep.c
index 35874eb..475ba2a 100644
--- a/gdb/arc-tdep.c
+++ b/gdb/arc-tdep.c
@@ -1002,7 +1002,7 @@ arc_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
   arc_debug_printf ("called");
 
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arc_gdbarch_tdep *tdep = (arc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int pc_offset = tdep->jb_pc * ARC_REGISTER_SIZE;
   gdb_byte buf[ARC_REGISTER_SIZE];
   CORE_ADDR jb_addr = get_frame_register_unsigned (frame, ARC_FIRST_ARG_REGNUM);
@@ -1832,7 +1832,8 @@ arc_make_sigtramp_frame_cache (struct frame_info *this_frame)
 {
   arc_debug_printf ("called");
 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  arc_gdbarch_tdep *tdep = (arc_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* Allocate new frame cache instance and space for saved register info.  */
   struct arc_frame_cache *cache = FRAME_OBSTACK_ZALLOC (struct arc_frame_cache);
@@ -1906,11 +1907,10 @@ arc_sigtramp_frame_sniffer (const struct frame_unwind *self,
 			    struct frame_info *this_frame,
 			    void **this_cache)
 {
-  struct gdbarch_tdep *tdep;
-
   arc_debug_printf ("called");
 
-  tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  arc_gdbarch_tdep *tdep = (arc_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* If we have a sigcontext_addr handler, then just return 1 (same as the
      "default_frame_sniffer ()").  */
@@ -2295,11 +2295,11 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* Allocate the ARC-private target-dependent information structure, and the
      GDB target-independent information structure.  */
-  gdb::unique_xmalloc_ptr<struct gdbarch_tdep> tdep
-    (XCNEW (struct gdbarch_tdep));
+  std::unique_ptr<arc_gdbarch_tdep> tdep_holder (new arc_gdbarch_tdep);
+  arc_gdbarch_tdep *tdep = tdep_holder.get ();
   tdep->jb_pc = -1; /* No longjmp support by default.  */
   tdep->has_hw_loops = arc_check_for_hw_loops (tdesc, tdesc_data.get ());
-  struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep.release ());
+  struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep_holder.release ());
 
   /* Data types.  */
   set_gdbarch_short_bit (gdbarch, 16);
@@ -2384,7 +2384,7 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
      It can override functions set earlier.  */
   gdbarch_init_osabi (info, gdbarch);
 
-  if (gdbarch_tdep (gdbarch)->jb_pc >= 0)
+  if (tdep->jb_pc >= 0)
     set_gdbarch_get_longjmp_target (gdbarch, arc_get_longjmp_target);
 
   /* Disassembler options.  Enforce CPU if it was specified in XML target
@@ -2454,7 +2454,7 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 arc_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arc_gdbarch_tdep *tdep = (arc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   fprintf_unfiltered (file, "arc_dump_tdep: jb_pc = %i\n", tdep->jb_pc);
 
diff --git a/gdb/arc-tdep.h b/gdb/arc-tdep.h
index 8bb005c..d8495ed 100644
--- a/gdb/arc-tdep.h
+++ b/gdb/arc-tdep.h
@@ -121,27 +121,27 @@ extern bool arc_debug;
 
 /* Target-dependent information.  */
 
-struct gdbarch_tdep
+struct arc_gdbarch_tdep : gdbarch_tdep
 {
   /* Offset to PC value in jump buffer.  If this is negative, longjmp
      support will be disabled.  */
-  int jb_pc;
+  int jb_pc = 0;
 
   /* Whether target has hardware (aka zero-delay) loops.  */
-  bool has_hw_loops;
+  bool has_hw_loops = false;
 
   /* Detect sigtramp.  */
-  bool (*is_sigtramp) (struct frame_info *);
+  bool (*is_sigtramp) (struct frame_info *) = nullptr;
 
   /* Get address of sigcontext for sigtramp.  */
-  CORE_ADDR (*sigcontext_addr) (struct frame_info *);
+  CORE_ADDR (*sigcontext_addr) (struct frame_info *) = nullptr;
 
   /* Offset of registers in `struct sigcontext'.  */
-  const int *sc_reg_offset;
+  const int *sc_reg_offset = nullptr;
 
   /* Number of registers in sc_reg_offsets.  Most likely a ARC_LAST_REGNUM,
      but in theory it could be less, so it is kept separate.  */
-  int sc_num_regs;
+  int sc_num_regs = 0;
 };
 
 /* Utility functions used by other ARC-specific modules.  */
diff --git a/gdb/arm-fbsd-tdep.c b/gdb/arm-fbsd-tdep.c
index 3a17918..a1482c4 100644
--- a/gdb/arm-fbsd-tdep.c
+++ b/gdb/arm-fbsd-tdep.c
@@ -158,7 +158,7 @@ arm_fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				       void *cb_data,
 				       const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", ARM_FBSD_SIZEOF_GREGSET, ARM_FBSD_SIZEOF_GREGSET,
       &arm_fbsd_gregset, NULL, cb_data);
@@ -211,7 +211,7 @@ arm_fbsd_core_read_description (struct gdbarch *gdbarch,
 static void
 arm_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Generic FreeBSD support.  */
   fbsd_init_abi (info, gdbarch);
diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c
index c0dfc5f..025ecf0 100644
--- a/gdb/arm-linux-tdep.c
+++ b/gdb/arm-linux-tdep.c
@@ -712,7 +712,7 @@ arm_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					void *cb_data,
 					const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", ARM_LINUX_SIZEOF_GREGSET, ARM_LINUX_SIZEOF_GREGSET,
       &arm_linux_gregset, NULL, cb_data);
@@ -1714,7 +1714,7 @@ arm_linux_init_abi (struct gdbarch_info info,
 								    NULL };
   static const char *const stap_register_indirection_suffixes[] = { "]",
 								    NULL };
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 1);
 
diff --git a/gdb/arm-netbsd-tdep.c b/gdb/arm-netbsd-tdep.c
index 38c2e81..bf4e46f 100644
--- a/gdb/arm-netbsd-tdep.c
+++ b/gdb/arm-netbsd-tdep.c
@@ -111,7 +111,7 @@ static void
 arm_netbsd_init_abi_common (struct gdbarch_info info,
 			    struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->lowest_pc = 0x8000;
   switch (info.byte_order)
@@ -148,7 +148,7 @@ static void
 arm_netbsd_elf_init_abi (struct gdbarch_info info,
 			 struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   arm_netbsd_init_abi_common (info, gdbarch);
 
diff --git a/gdb/arm-none-tdep.c b/gdb/arm-none-tdep.c
index 2816c59..a308c79 100644
--- a/gdb/arm-none-tdep.c
+++ b/gdb/arm-none-tdep.c
@@ -177,7 +177,7 @@ arm_none_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				       void *cb_data,
 				       const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", ARM_NONE_SIZEOF_GREGSET, ARM_NONE_SIZEOF_GREGSET,
       &arm_none_gregset, nullptr, cb_data);
diff --git a/gdb/arm-obsd-tdep.c b/gdb/arm-obsd-tdep.c
index ec7a748..4fa8853 100644
--- a/gdb/arm-obsd-tdep.c
+++ b/gdb/arm-obsd-tdep.c
@@ -76,7 +76,7 @@ static void
 armobsd_init_abi (struct gdbarch_info info,
 		  struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->fp_model == ARM_FLOAT_AUTO)
     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 5b60831..7495434 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -332,7 +332,9 @@ bool arm_apcs_32 = true;
 int
 arm_psr_thumb_bit (struct gdbarch *gdbarch)
 {
-  if (gdbarch_tdep (gdbarch)->is_m)
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  if (tdep->is_m)
     return XPSR_T;
   else
     return CPSR_T;
@@ -438,6 +440,7 @@ arm_pc_is_thumb (struct gdbarch *gdbarch, CORE_ADDR memaddr)
   struct bound_minimal_symbol sym;
   char type;
   arm_displaced_step_copy_insn_closure *dsc = nullptr;
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (gdbarch_displaced_step_copy_insn_closure_by_addr_p (gdbarch))
     dsc = ((arm_displaced_step_copy_insn_closure * )
@@ -465,7 +468,7 @@ arm_pc_is_thumb (struct gdbarch *gdbarch, CORE_ADDR memaddr)
     return 1;
 
   /* ARM v6-M and v7-M are always in Thumb mode.  */
-  if (gdbarch_tdep (gdbarch)->is_m)
+  if (tdep->is_m)
     return 1;
 
   /* If there are mapping symbols, consult them.  */
@@ -568,10 +571,11 @@ arm_m_addr_is_magic (CORE_ADDR addr)
 static CORE_ADDR
 arm_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR val)
 {
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   /* On M-profile devices, do not strip the low bit from EXC_RETURN
      (the magic exception return address).  */
-  if (gdbarch_tdep (gdbarch)->is_m
-      && arm_m_addr_is_magic (val))
+  if (tdep->is_m && arm_m_addr_is_magic (val))
     return val;
 
   if (arm_apcs_32)
@@ -1557,6 +1561,7 @@ arm_analyze_prologue (struct gdbarch *gdbarch,
   CORE_ADDR offset, current_pc;
   pv_t regs[ARM_FPS_REGNUM];
   CORE_ADDR unrecognized_pc = 0;
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Search the prologue looking for instructions that set up the
      frame pointer, adjust the stack pointer, and save registers.
@@ -1661,7 +1666,7 @@ arm_analyze_prologue (struct gdbarch *gdbarch,
 	}
       else if ((insn & 0xffff7fff) == 0xed6d0103	/* stfe f?,
 							   [sp, -#c]! */
-	       && gdbarch_tdep (gdbarch)->have_fpa_registers)
+	       && tdep->have_fpa_registers)
 	{
 	  if (stack.store_would_trash (regs[ARM_SP_REGNUM]))
 	    break;
@@ -1672,7 +1677,7 @@ arm_analyze_prologue (struct gdbarch *gdbarch,
 	}
       else if ((insn & 0xffbf0fff) == 0xec2d0200	/* sfmfd f0, 4,
 							   [sp!] */
-	       && gdbarch_tdep (gdbarch)->have_fpa_registers)
+	       && tdep->have_fpa_registers)
 	{
 	  int n_saved_fp_regs;
 	  unsigned int fp_start_reg, fp_bound_reg;
@@ -1800,6 +1805,7 @@ arm_scan_prologue (struct frame_info *this_frame,
   CORE_ADDR prologue_start, prologue_end;
   CORE_ADDR prev_pc = get_frame_pc (this_frame);
   CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Assume there is no frame until proven otherwise.  */
   cache->framereg = ARM_SP_REGNUM;
@@ -1865,7 +1871,7 @@ arm_scan_prologue (struct frame_info *this_frame,
       ULONGEST return_value;
 
       /* AAPCS does not use a frame register, so we can abort here.  */
-      if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_AAPCS)
+      if (tdep->arm_abi == ARM_ABI_AAPCS)
 	return;
 
       frame_loc = get_frame_register_unsigned (this_frame, ARM_FP_REGNUM);
@@ -1930,7 +1936,9 @@ arm_prologue_unwind_stop_reason (struct frame_info *this_frame,
 
   /* This is meant to halt the backtrace at "_start".  */
   pc = get_frame_pc (this_frame);
-  if (pc <= gdbarch_tdep (get_frame_arch (this_frame))->lowest_pc)
+  gdbarch *arch = get_frame_arch (this_frame);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (arch);
+  if (pc <= tdep->lowest_pc)
     return UNWIND_OUTERMOST;
 
   /* If we've hit a wall, stop.  */
@@ -3739,15 +3747,18 @@ arm_vfp_call_candidate (struct type *t, enum arm_vfp_cprc_base_type *base_type,
 static int
 arm_vfp_abi_for_function (struct gdbarch *gdbarch, struct type *func_type)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   /* Variadic functions always use the base ABI.  Assume that functions
      without debug info are not variadic.  */
   if (func_type && check_typedef (func_type)->has_varargs ())
     return 0;
+
   /* The VFP ABI is only supported as a variant of AAPCS.  */
   if (tdep->arm_abi != ARM_ABI_AAPCS)
     return 0;
-  return gdbarch_tdep (gdbarch)->fp_model == ARM_FLOAT_VFP;
+
+  return tdep->fp_model == ARM_FLOAT_VFP;
 }
 
 /* We currently only support passing parameters in integer registers, which
@@ -3770,6 +3781,7 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int use_vfp_abi;
   struct type *ftype;
   unsigned vfp_regs_free = (1 << 16) - 1;
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Determine the type of this function and whether the VFP ABI
      applies.  */
@@ -3827,7 +3839,7 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
       align = (align + ARM_INT_REGISTER_SIZE - 1)
 		& ~(ARM_INT_REGISTER_SIZE - 1);
       /* Different ABIs have different maximum alignments.  */
-      if (gdbarch_tdep (gdbarch)->arm_abi == ARM_ABI_APCS)
+      if (tdep->arm_abi == ARM_ABI_APCS)
 	{
 	  /* The APCS ABI only requires word alignment.  */
 	  align = ARM_INT_REGISTER_SIZE;
@@ -4041,7 +4053,7 @@ arm_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
 static struct type *
 arm_ext_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->arm_ext_type)
     tdep->arm_ext_type
@@ -4054,7 +4066,7 @@ arm_ext_type (struct gdbarch *gdbarch)
 static struct type *
 arm_neon_double_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->neon_double_type == NULL)
     {
@@ -4093,7 +4105,7 @@ arm_neon_double_type (struct gdbarch *gdbarch)
 static struct type *
 arm_neon_quad_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->neon_quad_type == NULL)
     {
@@ -4131,7 +4143,7 @@ arm_neon_quad_type (struct gdbarch *gdbarch)
 static bool
 is_q_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Q pseudo registers are available for both NEON (Q0~Q15) and
      MVE (Q0~Q7) features.  */
@@ -4152,7 +4164,7 @@ is_q_pseudo (struct gdbarch *gdbarch, int regnum)
 static bool
 is_s_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->have_s_pseudos
       && regnum >= tdep->s_pseudo_base
@@ -4171,7 +4183,7 @@ is_s_pseudo (struct gdbarch *gdbarch, int regnum)
 static bool
 is_mve_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->have_mve
       && regnum >= tdep->mve_pseudo_base
@@ -4187,7 +4199,7 @@ is_mve_pseudo (struct gdbarch *gdbarch, int regnum)
 static struct type *
 arm_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (is_s_pseudo (gdbarch, regnum))
     return builtin_type (gdbarch)->builtin_float;
@@ -4369,9 +4381,10 @@ arm_adjust_breakpoint_address (struct gdbarch *gdbarch, CORE_ADDR bpaddr)
   int buf_len;
   enum bfd_endian order = gdbarch_byte_order_for_code (gdbarch);
   int i, any, last_it, last_it_count;
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* If we are using BKPT breakpoints, none of this is necessary.  */
-  if (gdbarch_tdep (gdbarch)->thumb2_breakpoint == NULL)
+  if (tdep->thumb2_breakpoint == NULL)
     return bpaddr;
 
   /* ARM mode does not have this problem.  */
@@ -7676,7 +7689,7 @@ arm_displaced_init_closure (struct gdbarch *gdbarch, CORE_ADDR from,
 			    CORE_ADDR to,
 			    arm_displaced_step_copy_insn_closure *dsc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   unsigned int i, len, offset;
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
   int size = dsc->is_thumb? 2 : 4;
@@ -7839,7 +7852,7 @@ static const gdb_byte arm_default_thumb_be_breakpoint[] = THUMB_BE_BREAKPOINT;
 static int
 arm_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
 
   if (arm_pc_is_thumb (gdbarch, *pcptr))
@@ -7874,7 +7887,7 @@ arm_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 static const gdb_byte *
 arm_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   switch (kind)
     {
@@ -7946,10 +7959,11 @@ arm_extract_return_value (struct type *type, struct regcache *regs,
 {
   struct gdbarch *gdbarch = regs->arch ();
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (TYPE_CODE_FLT == type->code ())
     {
-      switch (gdbarch_tdep (gdbarch)->fp_model)
+      switch (tdep->fp_model)
 	{
 	case ARM_FLOAT_FPA:
 	  {
@@ -8055,7 +8069,8 @@ arm_return_in_memory (struct gdbarch *gdbarch, struct type *type)
       return (TYPE_LENGTH (type) > 16);
     }
 
-  if (gdbarch_tdep (gdbarch)->arm_abi != ARM_ABI_APCS)
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->arm_abi != ARM_ABI_APCS)
     {
       /* The AAPCS says all aggregates not larger than a word are returned
 	 in a register.  */
@@ -8158,8 +8173,9 @@ arm_store_return_value (struct type *type, struct regcache *regs,
   if (type->code () == TYPE_CODE_FLT)
     {
       gdb_byte buf[ARM_FP_REGISTER_SIZE];
+      arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
-      switch (gdbarch_tdep (gdbarch)->fp_model)
+      switch (tdep->fp_model)
 	{
 	case ARM_FLOAT_FPA:
 
@@ -8246,7 +8262,7 @@ arm_return_value (struct gdbarch *gdbarch, struct value *function,
 		  struct type *valtype, struct regcache *regcache,
 		  gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct type *func_type = function ? value_type (function) : NULL;
   enum arm_vfp_cprc_base_type vfp_base_type;
   int vfp_base_count;
@@ -8314,7 +8330,7 @@ static int
 arm_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR jb_addr;
   gdb_byte buf[ARM_INT_REGISTER_SIZE];
@@ -8503,7 +8519,8 @@ static void
 show_fp_model (struct ui_file *file, int from_tty,
 	       struct cmd_list_element *c, const char *value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (target_gdbarch ());
+  arm_gdbarch_tdep *tdep
+    = (arm_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
 
   if (arm_fp_model == ARM_FLOAT_AUTO
       && gdbarch_bfd_arch_info (target_gdbarch ())->arch == bfd_arch_arm)
@@ -8540,7 +8557,8 @@ static void
 arm_show_abi (struct ui_file *file, int from_tty,
 	     struct cmd_list_element *c, const char *value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (target_gdbarch ());
+  arm_gdbarch_tdep *tdep
+    = (arm_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
 
   if (arm_abi_global == ARM_ABI_AUTO
       && gdbarch_bfd_arch_info (target_gdbarch ())->arch == bfd_arch_arm)
@@ -8611,7 +8629,7 @@ show_disassembly_style_sfunc (struct ui_file *file, int from_tty,
 static const char *
 arm_register_name (struct gdbarch *gdbarch, int i)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (is_s_pseudo (gdbarch, i))
     {
@@ -8778,7 +8796,7 @@ static enum register_status
 arm_mve_pseudo_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 		     int regnum, gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* P0 is the first 16 bits of VPR.  */
   return regcache->raw_read_part (tdep->mve_vpr_regnum, 0, 2, buf);
@@ -8792,11 +8810,10 @@ arm_pseudo_read (struct gdbarch *gdbarch, readable_regcache *regcache,
   char name_buf[4];
   gdb_byte reg_buf[8];
   int offset, double_regnum;
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (regnum >= num_regs);
 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-
   if (is_q_pseudo (gdbarch, regnum))
     {
       /* Quad-precision register.  */
@@ -8865,7 +8882,7 @@ static void
 arm_mve_pseudo_write (struct gdbarch *gdbarch, struct regcache *regcache,
 		      int regnum, const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* P0 is the first 16 bits of VPR.  */
   regcache->raw_write_part (tdep->mve_vpr_regnum, 0, 2, buf);
@@ -8879,11 +8896,10 @@ arm_pseudo_write (struct gdbarch *gdbarch, struct regcache *regcache,
   char name_buf[4];
   gdb_byte reg_buf[8];
   int offset, double_regnum;
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (regnum >= num_regs);
 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-
   if (is_q_pseudo (gdbarch, regnum))
     {
       /* Quad-precision register.  */
@@ -8968,7 +8984,9 @@ arm_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 static void
 arm_register_g_packet_guesses (struct gdbarch *gdbarch)
 {
-  if (gdbarch_tdep (gdbarch)->is_m)
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  if (tdep->is_m)
     {
       const target_desc *tdesc;
 
@@ -9005,8 +9023,9 @@ arm_register_g_packet_guesses (struct gdbarch *gdbarch)
 static int
 arm_code_of_frame_writable (struct gdbarch *gdbarch, struct frame_info *frame)
 {
-  if (gdbarch_tdep (gdbarch)->is_m
-      && get_frame_type (frame) == SIGTRAMP_FRAME)
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  if (tdep->is_m && get_frame_type (frame) == SIGTRAMP_FRAME)
     {
       /* M-profile exception frames return to some magic PCs, where
 	 isn't writable at all.  */
@@ -9037,7 +9056,6 @@ arm_gnu_triplet_regexp (struct gdbarch *gdbarch)
 static struct gdbarch *
 arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
   struct gdbarch_list *best_arch;
   enum arm_abi_kind arm_abi = arm_abi_global;
@@ -9406,12 +9424,13 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch != NULL;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
-      if (arm_abi != ARM_ABI_AUTO
-	  && arm_abi != gdbarch_tdep (best_arch->gdbarch)->arm_abi)
+      arm_gdbarch_tdep *tdep
+	= (arm_gdbarch_tdep *) gdbarch_tdep (best_arch->gdbarch);
+
+      if (arm_abi != ARM_ABI_AUTO && arm_abi != tdep->arm_abi)
 	continue;
 
-      if (fp_model != ARM_FLOAT_AUTO
-	  && fp_model != gdbarch_tdep (best_arch->gdbarch)->fp_model)
+      if (fp_model != ARM_FLOAT_AUTO && fp_model != tdep->fp_model)
 	continue;
 
       /* There are various other properties in tdep that we do not
@@ -9420,7 +9439,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 	 automatically disqualified.  */
 
       /* Do check is_m, though, since it might come from the binary.  */
-      if (is_m != gdbarch_tdep (best_arch->gdbarch)->is_m)
+      if (is_m != tdep->is_m)
 	continue;
 
       /* Found a match.  */
@@ -9430,7 +9449,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   if (best_arch != NULL)
     return best_arch->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  arm_gdbarch_tdep *tdep = new arm_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Record additional information about the architecture we are defining.
@@ -9546,7 +9565,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* This "info float" is FPA-specific.  Use the generic version if we
      do not have FPA.  */
-  if (gdbarch_tdep (gdbarch)->have_fpa_registers)
+  if (tdep->have_fpa_registers)
     set_gdbarch_print_float_info (gdbarch, arm_print_float_info);
 
   /* Internal <-> external register number maps.  */
@@ -9692,7 +9711,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 arm_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep == NULL)
     return;
@@ -11868,7 +11887,8 @@ static int
 arm_record_coproc_data_proc (insn_decode_record *arm_insn_r)
 {
   uint32_t op, op1_ebit, coproc, bits_24_25;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arm_insn_r->gdbarch);
+  arm_gdbarch_tdep *tdep
+    = (arm_gdbarch_tdep *) gdbarch_tdep (arm_insn_r->gdbarch);
   struct regcache *reg_cache = arm_insn_r->regcache;
 
   arm_insn_r->opcode = bits (arm_insn_r->arm_insn, 24, 27);
@@ -12352,9 +12372,10 @@ thumb_record_misc (insn_decode_record *thumb_insn_r)
 /* Handling opcode 110 insns.  */
 
 static int
-thumb_record_ldm_stm_swi (insn_decode_record *thumb_insn_r)                
+thumb_record_ldm_stm_swi (insn_decode_record *thumb_insn_r)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (thumb_insn_r->gdbarch);
+  arm_gdbarch_tdep *tdep
+    = (arm_gdbarch_tdep *) gdbarch_tdep  (thumb_insn_r->gdbarch);
   struct regcache *reg_cache = thumb_insn_r->regcache;
 
   uint32_t ret = 0; /* function return value: -1:record failure ;  0:success  */
diff --git a/gdb/arm-tdep.h b/gdb/arm-tdep.h
index 705aa77..9012b9d 100644
--- a/gdb/arm-tdep.h
+++ b/gdb/arm-tdep.h
@@ -87,69 +87,70 @@ enum struct_return
 };
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct arm_gdbarch_tdep : gdbarch_tdep
 {
   /* The ABI for this architecture.  It should never be set to
      ARM_ABI_AUTO.  */
-  enum arm_abi_kind arm_abi;
+  enum arm_abi_kind arm_abi {};
 
-  enum arm_float_model fp_model; /* Floating point calling conventions.  */
+  enum arm_float_model fp_model {}; /* Floating point calling conventions.  */
 
-  bool have_fpa_registers;	/* Does the target report the FPA registers?  */
-  bool have_wmmx_registers;	/* Does the target report the WMMX registers?  */
+  bool have_fpa_registers = false;	/* Does the target report the FPA registers?  */
+  bool have_wmmx_registers = false;	/* Does the target report the WMMX registers?  */
   /* The number of VFP registers reported by the target.  It is zero
      if VFP registers are not supported.  */
-  int vfp_register_count;
-  bool have_s_pseudos;		/* Are we synthesizing the single precision
+  int vfp_register_count = 0;
+  bool have_s_pseudos = false;	/* Are we synthesizing the single precision
 				   VFP registers?  */
-  int s_pseudo_base;		/* Register number for the first S pseudo
+  int s_pseudo_base = 0;	/* Register number for the first S pseudo
 				   register.  */
-  int s_pseudo_count;		/* Number of S pseudo registers.  */
-  bool have_q_pseudos;		/* Are we synthesizing the quad precision
+  int s_pseudo_count = 0;	/* Number of S pseudo registers.  */
+  bool have_q_pseudos = false;	/* Are we synthesizing the quad precision
 				   Q (NEON or MVE) registers?  Requires
 				   have_s_pseudos.  */
-  int q_pseudo_base;		/* Register number for the first quad
+  int q_pseudo_base = 0;	/* Register number for the first quad
 				   precision pseudo register.  */
-  int q_pseudo_count;		/* Number of quad precision pseudo
+  int q_pseudo_count = 0;	/* Number of quad precision pseudo
 				   registers.  */
-  bool have_neon;		/* Do we have a NEON unit?  */
+  bool have_neon = false;	/* Do we have a NEON unit?  */
 
-  bool have_mve;		/* Do we have a MVE extension?  */
-  int mve_vpr_regnum;		/* MVE VPR register number.  */
-  int mve_pseudo_base;		/* Number of the first MVE pseudo register.  */
-  int mve_pseudo_count;		/* Total number of MVE pseudo registers.  */
+  bool have_mve = false;	/* Do we have a MVE extension?  */
+  int mve_vpr_regnum = 0;	/* MVE VPR register number.  */
+  int mve_pseudo_base = 0;	/* Number of the first MVE pseudo register.  */
+  int mve_pseudo_count = 0;	/* Total number of MVE pseudo registers.  */
 
-  bool is_m;			/* Does the target follow the "M" profile.  */
-  CORE_ADDR lowest_pc;		/* Lowest address at which instructions 
+  bool is_m = false;		/* Does the target follow the "M" profile.  */
+  CORE_ADDR lowest_pc = 0;	/* Lowest address at which instructions
 				   will appear.  */
 
-  const gdb_byte *arm_breakpoint;	/* Breakpoint pattern for an ARM insn.  */
-  int arm_breakpoint_size;	/* And its size.  */
-  const gdb_byte *thumb_breakpoint;	/* Breakpoint pattern for a Thumb insn.  */
-  int thumb_breakpoint_size;	/* And its size.  */
+  const gdb_byte *arm_breakpoint = nullptr;	/* Breakpoint pattern for an ARM insn.  */
+  int arm_breakpoint_size = 0;	/* And its size.  */
+  const gdb_byte *thumb_breakpoint = nullptr;	/* Breakpoint pattern for a Thumb insn.  */
+  int thumb_breakpoint_size = 0;	/* And its size.  */
 
   /* If the Thumb breakpoint is an undefined instruction (which is
      affected by IT blocks) rather than a BKPT instruction (which is
      not), then we need a 32-bit Thumb breakpoint to preserve the
      instruction count in IT blocks.  */
-  const gdb_byte *thumb2_breakpoint;
-  int thumb2_breakpoint_size;
+  const gdb_byte *thumb2_breakpoint = nullptr;
+  int thumb2_breakpoint_size = 0;
 
-  int jb_pc;			/* Offset to PC value in jump buffer.
+  int jb_pc = 0;			/* Offset to PC value in jump buffer.
 				   If this is negative, longjmp support
 				   will be disabled.  */
-  size_t jb_elt_size;		/* And the size of each entry in the buf.  */
+  size_t jb_elt_size = 0;		/* And the size of each entry in the buf.  */
 
   /* Convention for returning structures.  */
-  enum struct_return struct_return;
+  enum struct_return struct_return {};
 
   /* ISA-specific data types.  */
-  struct type *arm_ext_type;
-  struct type *neon_double_type;
-  struct type *neon_quad_type;
+  struct type *arm_ext_type = nullptr;
+  struct type *neon_double_type = nullptr;
+  struct type *neon_quad_type = nullptr;
 
    /* syscall record.  */
-  int (*arm_syscall_record) (struct regcache *regcache, unsigned long svc_number);
+  int (*arm_syscall_record) (struct regcache *regcache,
+			     unsigned long svc_number) = nullptr;
 };
 
 /* Structures used for displaced stepping.  */
diff --git a/gdb/arm-wince-tdep.c b/gdb/arm-wince-tdep.c
index f81a054..46cf835 100644
--- a/gdb/arm-wince-tdep.c
+++ b/gdb/arm-wince-tdep.c
@@ -115,7 +115,7 @@ arm_wince_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 static void
 arm_wince_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   windows_init_abi (info, gdbarch);
 
diff --git a/gdb/avr-tdep.c b/gdb/avr-tdep.c
index ea259b9..0db1986 100644
--- a/gdb/avr-tdep.c
+++ b/gdb/avr-tdep.c
@@ -188,18 +188,18 @@ struct avr_unwind_cache
   trad_frame_saved_reg *saved_regs;
 };
 
-struct gdbarch_tdep
+struct avr_gdbarch_tdep : gdbarch_tdep
 {
   /* Number of bytes stored to the stack by call instructions.
      2 bytes for avr1-5 and avrxmega1-5, 3 bytes for avr6 and avrxmega6-7.  */
-  int call_length;
+  int call_length = 0;
 
   /* Type for void.  */
-  struct type *void_type;
+  struct type *void_type = nullptr;
   /* Type for a function returning void.  */
-  struct type *func_void_type;
+  struct type *func_void_type = nullptr;
   /* Type for a pointer to a function.  Used for the type of PC.  */
-  struct type *pc_type;
+  struct type *pc_type = nullptr;
 };
 
 /* Lookup the name of a register given it's number.  */
@@ -230,10 +230,14 @@ avr_register_type (struct gdbarch *gdbarch, int reg_nr)
 {
   if (reg_nr == AVR_PC_REGNUM)
     return builtin_type (gdbarch)->builtin_uint32;
+
+  avr_gdbarch_tdep *tdep = (avr_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (reg_nr == AVR_PSEUDO_PC_REGNUM)
-    return gdbarch_tdep (gdbarch)->pc_type;
+    return tdep->pc_type;
+
   if (reg_nr == AVR_SP_REGNUM)
     return builtin_type (gdbarch)->builtin_data_ptr;
+
   return builtin_type (gdbarch)->builtin_uint8;
 }
 
@@ -745,13 +749,13 @@ avr_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR pc_beg, CORE_ADDR pc_end,
   gdb_assert (vpc < AVR_MAX_PROLOGUE_SIZE);
 
   /* Handle static small stack allocation using rcall or push.  */
-
+  avr_gdbarch_tdep *tdep = (avr_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   while (scan_stage == 1 && vpc < len)
     {
       insn = extract_unsigned_integer (&prologue[vpc], 2, byte_order);
       if (insn == 0xd000)	/* rcall .+0 */
 	{
-	  info->size += gdbarch_tdep (gdbarch)->call_length;
+	  info->size += tdep->call_length;
 	  vpc += 2;
 	}
       else if (insn == 0x920f || insn == 0x921f)  /* push r0 or push r1 */
@@ -984,7 +988,6 @@ avr_frame_unwind_cache (struct frame_info *this_frame,
   ULONGEST this_base;
   struct avr_unwind_cache *info;
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int i;
 
   if (*this_prologue_cache)
@@ -1049,7 +1052,7 @@ avr_frame_unwind_cache (struct frame_info *this_frame,
 
   /* The previous frame's SP needed to be computed.  Save the computed
      value.  */
-  tdep = gdbarch_tdep (gdbarch);
+  avr_gdbarch_tdep *tdep = (avr_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   info->saved_regs[AVR_SP_REGNUM].set_value (info->prev_sp
 					     - 1 + tdep->call_length);
 
@@ -1131,7 +1134,7 @@ avr_frame_prev_register (struct frame_info *this_frame,
 	  int i;
 	  gdb_byte buf[3];
 	  struct gdbarch *gdbarch = get_frame_arch (this_frame);
-	  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+	  avr_gdbarch_tdep *tdep = (avr_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
 	  read_memory (info->saved_regs[AVR_PC_REGNUM].addr (),
 		       buf, tdep->call_length);
@@ -1273,7 +1276,8 @@ avr_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 {
   int i;
   gdb_byte buf[3];
-  int call_length = gdbarch_tdep (gdbarch)->call_length;
+  avr_gdbarch_tdep *tdep = (avr_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int call_length = tdep->call_length;
   CORE_ADDR return_pc = avr_convert_iaddr_to_raw (bp_addr);
   int regnum = AVR_ARGN_REGNUM;
   struct stack_item *si = NULL;
@@ -1424,7 +1428,6 @@ static struct gdbarch *
 avr_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   struct gdbarch_list *best_arch;
   int call_length;
 
@@ -1456,12 +1459,15 @@ avr_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch != NULL;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
-      if (gdbarch_tdep (best_arch->gdbarch)->call_length == call_length)
+      avr_gdbarch_tdep *tdep
+	= (avr_gdbarch_tdep *) gdbarch_tdep (best_arch->gdbarch);
+
+      if (tdep->call_length == call_length)
 	return best_arch->gdbarch;
     }
 
   /* None found, create a new architecture from the information provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  avr_gdbarch_tdep *tdep = new avr_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   
   tdep->call_length = call_length;
diff --git a/gdb/bfin-tdep.c b/gdb/bfin-tdep.c
index d381f92..355f9f4 100644
--- a/gdb/bfin-tdep.c
+++ b/gdb/bfin-tdep.c
@@ -766,7 +766,8 @@ bfin_frame_align (struct gdbarch *gdbarch, CORE_ADDR address)
 enum bfin_abi
 bfin_abi (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->bfin_abi;
+  bfin_gdbarch_tdep *tdep = (bfin_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->bfin_abi;
 }
 
 /* Initialize the current architecture based on INFO.  If possible,
@@ -779,7 +780,6 @@ bfin_abi (struct gdbarch *gdbarch)
 static struct gdbarch *
 bfin_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
   enum bfin_abi abi;
 
@@ -791,12 +791,16 @@ bfin_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      if (gdbarch_tdep (arches->gdbarch)->bfin_abi != abi)
+      bfin_gdbarch_tdep *tdep
+	= (bfin_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
+      if (tdep->bfin_abi != abi)
 	continue;
+
       return arches->gdbarch;
     }
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  bfin_gdbarch_tdep *tdep = new bfin_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   tdep->bfin_abi = abi;
diff --git a/gdb/bfin-tdep.h b/gdb/bfin-tdep.h
index 309d4f4..70a1854 100644
--- a/gdb/bfin-tdep.h
+++ b/gdb/bfin-tdep.h
@@ -94,10 +94,10 @@ enum bfin_abi
 };
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct bfin_gdbarch_tdep : gdbarch_tdep
 {
   /* Which ABI is in use?  */
-  enum bfin_abi bfin_abi;
+  enum bfin_abi bfin_abi {};
 };
 
 /* Return the Blackfin ABI associated with GDBARCH.  */
diff --git a/gdb/bpf-tdep.c b/gdb/bpf-tdep.c
index e520d5d..b2cd913 100644
--- a/gdb/bpf-tdep.c
+++ b/gdb/bpf-tdep.c
@@ -57,7 +57,7 @@ enum bpf_regnum
 #define BPF_NUM_REGS	(BPF_PC_REGNUM + 1)
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct bpf_gdbarch_tdep : gdbarch_tdep
 {
 };
 
@@ -321,7 +321,7 @@ bpf_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Allocate space for the new architecture.  */
-  struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
+  bpf_gdbarch_tdep *tdep = new bpf_gdbarch_tdep;
   struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Information about registers, etc.  */
diff --git a/gdb/cris-linux-tdep.c b/gdb/cris-linux-tdep.c
index 68a12db..e7dbded 100644
--- a/gdb/cris-linux-tdep.c
+++ b/gdb/cris-linux-tdep.c
@@ -33,7 +33,7 @@
 static void
 cris_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/cris-tdep.c b/gdb/cris-tdep.c
index 6b5dfc3..691cad8 100644
--- a/gdb/cris-tdep.c
+++ b/gdb/cris-tdep.c
@@ -313,7 +313,7 @@ cris_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
 				  void **this_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct cris_unwind_cache *info;
   CORE_ADDR addr;
@@ -450,7 +450,7 @@ static int
 crisv32_single_step_through_delay (struct gdbarch *gdbarch,
 				   struct frame_info *this_frame)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST erp;
   int ret = 0;
 
@@ -695,7 +695,7 @@ cris_frame_unwind_cache (struct frame_info *this_frame,
 			 void **this_prologue_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct cris_unwind_cache *info;
 
   if ((*this_prologue_cache))
@@ -1333,7 +1333,7 @@ crisv32_scan_prologue (CORE_ADDR pc, struct frame_info *this_frame,
 static CORE_ADDR
 cris_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR func_addr, func_end;
   struct symtab_and_line sal;
   CORE_ADDR pc_after_prologue;
@@ -1368,7 +1368,7 @@ cris_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 static const gdb_byte *
 cris_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   static unsigned char break8_insn[] = {0x38, 0xe9};
   static unsigned char break15_insn[] = {0x3f, 0xe9};
 
@@ -1387,7 +1387,7 @@ static int
 cris_spec_reg_applicable (struct gdbarch *gdbarch,
 			  struct cris_spec_reg spec_reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   unsigned int version = tdep->cris_version;
   
   switch (spec_reg.applicable_version)
@@ -3766,7 +3766,7 @@ cris_supply_gregset (const struct regset *regset, struct regcache *regcache,
 		     int regnum, const void *gregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int i;
   const cris_elf_greg_t *regp = static_cast<const cris_elf_greg_t *>(gregs);
 
@@ -3860,7 +3860,7 @@ Makes GDB use the NRP register instead of the ERP register in certain cases."),
 static void
 cris_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  cris_gdbarch_tdep *tdep = (cris_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep != NULL)
     {
       fprintf_unfiltered (file, "cris_dump_tdep: tdep->cris_version = %i\n",
@@ -3914,7 +3914,6 @@ static struct gdbarch *
 cris_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   unsigned int cris_version;
 
   if (usr_cmd_cris_version_valid)
@@ -3940,17 +3939,17 @@ cris_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      if ((gdbarch_tdep (arches->gdbarch)->cris_version 
-	   == usr_cmd_cris_version)
-	  && (gdbarch_tdep (arches->gdbarch)->cris_mode 
-	   == usr_cmd_cris_mode)
-	  && (gdbarch_tdep (arches->gdbarch)->cris_dwarf2_cfi 
-	      == usr_cmd_cris_dwarf2_cfi))
+      cris_gdbarch_tdep *tdep
+	= (cris_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
+      if (tdep->cris_version == usr_cmd_cris_version
+	  && tdep->cris_mode == usr_cmd_cris_mode
+	  && tdep->cris_dwarf2_cfi == usr_cmd_cris_dwarf2_cfi)
 	return arches->gdbarch;
     }
 
   /* No matching architecture was found.  Create a new one.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  cris_gdbarch_tdep *tdep = new cris_gdbarch_tdep;
   info.byte_order = BFD_ENDIAN_LITTLE;
   gdbarch = gdbarch_alloc (&info, tdep);
 
diff --git a/gdb/cris-tdep.h b/gdb/cris-tdep.h
index d898f4d..9b62294 100644
--- a/gdb/cris-tdep.h
+++ b/gdb/cris-tdep.h
@@ -24,11 +24,11 @@
 #define CRIS_TDEP_H
 
 /* CRIS architecture specific information.  */
-struct gdbarch_tdep
+struct cris_gdbarch_tdep : gdbarch_tdep
 {
-  unsigned int cris_version;
-  const char *cris_mode;
-  int cris_dwarf2_cfi;
+  unsigned int cris_version = 0;
+  const char *cris_mode = nullptr;
+  int cris_dwarf2_cfi = 0;
 };
 
 #endif /* CRIS_TDEP_H */
diff --git a/gdb/csky-tdep.c b/gdb/csky-tdep.c
index 8835aba..0b073fb 100644
--- a/gdb/csky-tdep.c
+++ b/gdb/csky-tdep.c
@@ -2164,7 +2164,6 @@ static struct gdbarch *
 csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* Find a candidate among the list of pre-declared architectures.  */
   arches = gdbarch_list_lookup_by_info (arches, &info);
@@ -2173,7 +2172,7 @@ csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* None found, create a new architecture from the information
      provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  csky_gdbarch_tdep *tdep = new csky_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Target data types.  */
diff --git a/gdb/csky-tdep.h b/gdb/csky-tdep.h
index 7fc1a92..d690e8f 100644
--- a/gdb/csky-tdep.h
+++ b/gdb/csky-tdep.h
@@ -29,7 +29,7 @@ enum lr_type_t
 };
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct csky_gdbarch_tdep : gdbarch_tdep
 {
   /* This is Unused.  */
 };
diff --git a/gdb/frv-tdep.c b/gdb/frv-tdep.c
index e105c27..c74ea68 100644
--- a/gdb/frv-tdep.c
+++ b/gdb/frv-tdep.c
@@ -67,32 +67,33 @@ struct frv_unwind_cache		/* was struct frame_extra_info */
    of structures, each of which gives all the necessary info for one
    register.  Don't stick parallel arrays in here --- that's so
    Fortran.  */
-struct gdbarch_tdep
+struct frv_gdbarch_tdep : gdbarch_tdep
 {
   /* Which ABI is in use?  */
-  enum frv_abi frv_abi;
+  enum frv_abi frv_abi {};
 
   /* How many general-purpose registers does this variant have?  */
-  int num_gprs;
+  int num_gprs = 0;
 
   /* How many floating-point registers does this variant have?  */
-  int num_fprs;
+  int num_fprs = 0;
 
   /* How many hardware watchpoints can it support?  */
-  int num_hw_watchpoints;
+  int num_hw_watchpoints = 0;
 
   /* How many hardware breakpoints can it support?  */
-  int num_hw_breakpoints;
+  int num_hw_breakpoints = 0;
 
   /* Register names.  */
-  const char **register_names;
+  const char **register_names = nullptr;
 };
 
 /* Return the FR-V ABI associated with GDBARCH.  */
 enum frv_abi
 frv_abi (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->frv_abi;
+  frv_gdbarch_tdep *tdep = (frv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->frv_abi;
 }
 
 /* Fetch the interpreter and executable loadmap addresses (for shared
@@ -128,13 +129,12 @@ frv_fdpic_loadmap_addresses (struct gdbarch *gdbarch, CORE_ADDR *interp_addr,
 
 /* Allocate a new variant structure, and set up default values for all
    the fields.  */
-static struct gdbarch_tdep *
+static frv_gdbarch_tdep *
 new_variant (void)
 {
-  struct gdbarch_tdep *var;
   int r;
 
-  var = XCNEW (struct gdbarch_tdep);
+  frv_gdbarch_tdep *var = new frv_gdbarch_tdep;
 
   var->frv_abi = FRV_ABI_EABI;
   var->num_gprs = 64;
@@ -219,7 +219,7 @@ new_variant (void)
 /* Indicate that the variant VAR has NUM_GPRS general-purpose
    registers, and fill in the names array appropriately.  */
 static void
-set_variant_num_gprs (struct gdbarch_tdep *var, int num_gprs)
+set_variant_num_gprs (frv_gdbarch_tdep *var, int num_gprs)
 {
   int r;
 
@@ -238,7 +238,7 @@ set_variant_num_gprs (struct gdbarch_tdep *var, int num_gprs)
 /* Indicate that the variant VAR has NUM_FPRS floating-point
    registers, and fill in the names array appropriately.  */
 static void
-set_variant_num_fprs (struct gdbarch_tdep *var, int num_fprs)
+set_variant_num_fprs (frv_gdbarch_tdep *var, int num_fprs)
 {
   int r;
 
@@ -254,7 +254,7 @@ set_variant_num_fprs (struct gdbarch_tdep *var, int num_fprs)
 }
 
 static void
-set_variant_abi_fdpic (struct gdbarch_tdep *var)
+set_variant_abi_fdpic (frv_gdbarch_tdep *var)
 {
   var->frv_abi = FRV_ABI_FDPIC;
   var->register_names[fdpic_loadmap_exec_regnum] = xstrdup ("loadmap_exec");
@@ -263,7 +263,7 @@ set_variant_abi_fdpic (struct gdbarch_tdep *var)
 }
 
 static void
-set_variant_scratch_registers (struct gdbarch_tdep *var)
+set_variant_scratch_registers (frv_gdbarch_tdep *var)
 {
   var->register_names[scr0_regnum] = xstrdup ("scr0");
   var->register_names[scr1_regnum] = xstrdup ("scr1");
@@ -276,10 +276,12 @@ frv_register_name (struct gdbarch *gdbarch, int reg)
 {
   if (reg < 0)
     return "?toosmall?";
+
   if (reg >= frv_num_regs + frv_num_pseudo_regs)
     return "?toolarge?";
 
-  return gdbarch_tdep (gdbarch)->register_names[reg];
+  frv_gdbarch_tdep *tdep = (frv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->register_names[reg];
 }
 
 
@@ -1439,7 +1441,6 @@ static struct gdbarch *
 frv_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *var;
   int elf_flags = 0;
 
   /* Check to see if we've already built an appropriate architecture
@@ -1449,7 +1450,7 @@ frv_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Select the right tdep structure for this variant.  */
-  var = new_variant ();
+  frv_gdbarch_tdep *var = new_variant ();
   switch (info.bfd_arch_info->mach)
     {
     case bfd_mach_frv:
diff --git a/gdb/ft32-tdep.c b/gdb/ft32-tdep.c
index ff03acb..eec800c 100644
--- a/gdb/ft32-tdep.c
+++ b/gdb/ft32-tdep.c
@@ -109,7 +109,10 @@ static struct type *
 ft32_register_type (struct gdbarch *gdbarch, int reg_nr)
 {
   if (reg_nr == FT32_PC_REGNUM)
-    return gdbarch_tdep (gdbarch)->pc_type;
+    {
+      ft32_gdbarch_tdep *tdep = (ft32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+      return tdep->pc_type;
+    }
   else if (reg_nr == FT32_SP_REGNUM || reg_nr == FT32_FP_REGNUM)
     return builtin_type (gdbarch)->builtin_data_ptr;
   else
@@ -559,7 +562,6 @@ static struct gdbarch *
 ft32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   struct type *void_type;
   struct type *func_void_type;
 
@@ -569,7 +571,7 @@ ft32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Allocate space for the new architecture.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  ft32_gdbarch_tdep *tdep = new ft32_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Create a type for PC.  We can't use builtin types here, as they may not
diff --git a/gdb/ft32-tdep.h b/gdb/ft32-tdep.h
index 0303801..c32f646 100644
--- a/gdb/ft32-tdep.h
+++ b/gdb/ft32-tdep.h
@@ -20,10 +20,10 @@
 #ifndef FT32_TDEP_H
 #define FT32_TDEP_H
 
-struct gdbarch_tdep
+struct ft32_gdbarch_tdep : gdbarch_tdep
 {
   /* Type for a pointer to a function.  Used for the type of PC.  */
-  struct type *pc_type;
+  struct type *pc_type = nullptr;
 };
 
 #endif /* FT32_TDEP_H */
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 979159b..f73d562 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -62,6 +62,8 @@ struct inferior;
 
 #include "regcache.h"
 
+struct gdbarch_tdep {};
+
 /* The architecture associated with the inferior through the
    connection to the target.
 
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 39a99d0..829f241 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1333,6 +1333,8 @@
 
 #include "regcache.h"
 
+struct gdbarch_tdep {};
+
 /* The architecture associated with the inferior through the
    connection to the target.
 
diff --git a/gdb/hppa-bsd-tdep.c b/gdb/hppa-bsd-tdep.c
index c68aaf1..f4567b4 100644
--- a/gdb/hppa-bsd-tdep.c
+++ b/gdb/hppa-bsd-tdep.c
@@ -118,7 +118,7 @@ hppabsd_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
 void
 hppabsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* OpenBSD and NetBSD have a 64-bit 'long double'.  */
   set_gdbarch_long_double_bit (gdbarch, 64);
diff --git a/gdb/hppa-linux-tdep.c b/gdb/hppa-linux-tdep.c
index 52c642f..1dd6993 100644
--- a/gdb/hppa-linux-tdep.c
+++ b/gdb/hppa-linux-tdep.c
@@ -476,7 +476,7 @@ hppa_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					 void *cb_data,
 					 const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", 80 * tdep->bytes_per_address, 80 * tdep->bytes_per_address,
       &hppa_linux_regset, NULL, cb_data);
@@ -486,7 +486,7 @@ hppa_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 static void
 hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/hppa-tdep.c b/gdb/hppa-tdep.c
index 344022c..d64f9f7 100644
--- a/gdb/hppa-tdep.c
+++ b/gdb/hppa-tdep.c
@@ -259,6 +259,7 @@ internalize_unwinds (struct objfile *objfile, struct unwind_table_entry *table,
   if (size > 0)
     {
       struct gdbarch *gdbarch = objfile->arch ();
+      hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       unsigned long tmp;
       unsigned i;
       char *buf = (char *) alloca (size);
@@ -270,7 +271,7 @@ internalize_unwinds (struct objfile *objfile, struct unwind_table_entry *table,
 	 Note that when loading a shared library (text_offset != 0) the
 	 unwinds are already relative to the text_offset that will be
 	 passed in.  */
-      if (gdbarch_tdep (gdbarch)->is_elf && text_offset == 0)
+      if (tdep->is_elf && text_offset == 0)
 	{
 	  low_text_segment_address = -1;
 
@@ -280,9 +281,9 @@ internalize_unwinds (struct objfile *objfile, struct unwind_table_entry *table,
 
 	  text_offset = low_text_segment_address;
 	}
-      else if (gdbarch_tdep (gdbarch)->solib_get_text_base)
+      else if (tdep->solib_get_text_base)
 	{
-	  text_offset = gdbarch_tdep (gdbarch)->solib_get_text_base (objfile);
+	  text_offset = tdep->solib_get_text_base (objfile);
 	}
 
       bfd_get_section_contents (objfile->obfd, section, buf, 0, size);
@@ -730,7 +731,7 @@ hppa32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   /* Global pointer (r19) of the function we are trying to call.  */
   CORE_ADDR gp;
 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   for (write_pass = 0; write_pass < 2; write_pass++)
     {
@@ -967,7 +968,7 @@ hppa64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 			function_call_return_method return_method,
 			CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int i, offset = 0;
   CORE_ADDR gp;
@@ -2253,9 +2254,7 @@ hppa_frame_cache (struct frame_info *this_frame, void **this_cache)
   }
 
   {
-    struct gdbarch_tdep *tdep;
-
-    tdep = gdbarch_tdep (gdbarch);
+    hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
     if (tdep->unwind_adjust_stub)
       tdep->unwind_adjust_stub (this_frame, cache->base, cache->saved_regs);
@@ -2485,7 +2484,7 @@ hppa_stub_unwind_sniffer (const struct frame_unwind *self,
 {
   CORE_ADDR pc = get_frame_address_in_block (this_frame);
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (pc == 0
       || (tdep->in_solib_call_trampoline != NULL
@@ -3029,7 +3028,6 @@ hppa_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 static struct gdbarch *
 hppa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
 
   /* find a candidate among the list of pre-declared architectures.  */
@@ -3038,7 +3036,7 @@ hppa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return (arches->gdbarch);
 
   /* If none found, then allocate and initialize one.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  hppa_gdbarch_tdep *tdep = new hppa_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Determine from the bfd_arch_info structure if we are dealing with
@@ -3162,7 +3160,7 @@ hppa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 hppa_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  hppa_gdbarch_tdep *tdep = (hppa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   fprintf_unfiltered (file, "bytes_per_address = %d\n", 
 		      tdep->bytes_per_address);
diff --git a/gdb/hppa-tdep.h b/gdb/hppa-tdep.h
index d033c14..7298881 100644
--- a/gdb/hppa-tdep.h
+++ b/gdb/hppa-tdep.h
@@ -20,6 +20,8 @@
 #ifndef HPPA_TDEP_H
 #define HPPA_TDEP_H
 
+#include "gdbarch.h"
+
 struct trad_frame_saved_reg;
 struct objfile;
 struct so_list;
@@ -82,24 +84,25 @@ enum hppa_regnum
 #define HPPA_INSN_SIZE 4
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct hppa_gdbarch_tdep : gdbarch_tdep
 {
   /* The number of bytes in an address.  For now, this field is designed
      to allow us to differentiate hppa32 from hppa64 targets.  */
-  int bytes_per_address;
+  int bytes_per_address = 0;
 
   /* Is this an ELF target? This can be 64-bit HP-UX, or a 32/64-bit GNU/Linux
      system.  */
-  int is_elf;
+  int is_elf = 0;
 
   /* Given a function address, try to find the global pointer for the 
      corresponding shared object.  */
-  CORE_ADDR (*find_global_pointer) (struct gdbarch *, struct value *);
+  CORE_ADDR (*find_global_pointer) (struct gdbarch *, struct value *) = nullptr;
 
   /* For shared libraries, each call goes through a small piece of
      trampoline code in the ".plt" section.  IN_SOLIB_CALL_TRAMPOLINE
      evaluates to nonzero if we are currently stopped in one of these.  */
-  int (*in_solib_call_trampoline) (struct gdbarch *gdbarch, CORE_ADDR pc);
+  int (*in_solib_call_trampoline) (struct gdbarch *gdbarch,
+				   CORE_ADDR pc) = nullptr;
 
   /* For targets that support multiple spaces, we may have additional stubs
      in the return path.  These stubs are internal to the ABI, and users are
@@ -107,14 +110,14 @@ struct gdbarch_tdep
      adjust the pc to the real caller.  This improves the behavior of commands
      that traverse frames such as "up" and "finish".  */
   void (*unwind_adjust_stub) (struct frame_info *this_frame, CORE_ADDR base,
-			      trad_frame_saved_reg *saved_regs);
+			      trad_frame_saved_reg *saved_regs) = nullptr;
 
   /* These are solib-dependent methods.  They are really HPUX only, but
      we don't have a HPUX-specific tdep vector at the moment.  */
-  CORE_ADDR (*solib_thread_start_addr) (struct so_list *so);
-  CORE_ADDR (*solib_get_got_by_pc) (CORE_ADDR addr);
-  CORE_ADDR (*solib_get_solib_by_pc) (CORE_ADDR addr);
-  CORE_ADDR (*solib_get_text_base) (struct objfile *objfile);
+  CORE_ADDR (*solib_thread_start_addr) (struct so_list *so) = nullptr;
+  CORE_ADDR (*solib_get_got_by_pc) (CORE_ADDR addr) = nullptr;
+  CORE_ADDR (*solib_get_solib_by_pc) (CORE_ADDR addr) = nullptr;
+  CORE_ADDR (*solib_get_text_base) (struct objfile *objfile) = nullptr;
 };
 
 /*
diff --git a/gdb/i386-bsd-tdep.c b/gdb/i386-bsd-tdep.c
index fb5fcaa..7bddc7a 100644
--- a/gdb/i386-bsd-tdep.c
+++ b/gdb/i386-bsd-tdep.c
@@ -74,7 +74,7 @@ int i386bsd_sc_reg_offset[] =
 void
 i386bsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->jb_pc_offset = 0;
 
diff --git a/gdb/i386-darwin-tdep.c b/gdb/i386-darwin-tdep.c
index c038d8b..900a0a6 100644
--- a/gdb/i386-darwin-tdep.c
+++ b/gdb/i386-darwin-tdep.c
@@ -156,7 +156,7 @@ i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 			     function_call_return_method return_method,
 			     CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   gdb_byte buf[4];
   int i;
@@ -248,7 +248,7 @@ i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 static void
 i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* We support the SSE registers.  */
   tdep->num_xmm_regs = I386_NUM_XREGS - 1;
diff --git a/gdb/i386-fbsd-tdep.c b/gdb/i386-fbsd-tdep.c
index 1039724..01db76f 100644
--- a/gdb/i386-fbsd-tdep.c
+++ b/gdb/i386-fbsd-tdep.c
@@ -308,7 +308,7 @@ i386fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				       void *cb_data,
 				       const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", tdep->sizeof_gregset, tdep->sizeof_gregset, &i386_gregset, NULL,
       cb_data);
@@ -327,7 +327,7 @@ static CORE_ADDR
 i386fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 				   CORE_ADDR lm_addr, CORE_ADDR offset)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct regcache *regcache;
 
   if (tdep->fsbase_regnum == -1)
@@ -349,7 +349,7 @@ i386fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 static void
 i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Obviously FreeBSD is BSD-based.  */
   i386bsd_init_abi (info, gdbarch);
@@ -418,7 +418,7 @@ int i386fbsd4_sc_reg_offset[] =
 static void
 i386fbsd4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Generic FreeBSD support. */
   fbsd_init_abi (info, gdbarch);
diff --git a/gdb/i386-gnu-tdep.c b/gdb/i386-gnu-tdep.c
index 33ccd3b..1f5e5f7 100644
--- a/gdb/i386-gnu-tdep.c
+++ b/gdb/i386-gnu-tdep.c
@@ -173,7 +173,7 @@ static int i386gnu_gregset_reg_offset[] =
 static void
 i386gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* GNU uses ELF.  */
   i386_elf_init_abi (info, gdbarch);
diff --git a/gdb/i386-go32-tdep.c b/gdb/i386-go32-tdep.c
index 7b9a4ca..31aef42 100644
--- a/gdb/i386-go32-tdep.c
+++ b/gdb/i386-go32-tdep.c
@@ -26,7 +26,7 @@
 static void
 i386_go32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* DJGPP doesn't have any special frames for signal handlers.  */
   tdep->sigtramp_p = NULL;
diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c
index 1c065ee..898b73f 100644
--- a/gdb/i386-linux-tdep.c
+++ b/gdb/i386-linux-tdep.c
@@ -762,7 +762,7 @@ i386_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					 void *cb_data,
 					 const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", 68, 68, &i386_gregset, NULL, cb_data);
 
@@ -824,7 +824,7 @@ i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
 static void
 i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const struct target_desc *tdesc = info.target_desc;
   struct tdesc_arch_data *tdesc_data = info.tdesc_data;
   const struct tdesc_feature *feature;
diff --git a/gdb/i386-netbsd-tdep.c b/gdb/i386-netbsd-tdep.c
index 76dcc4d..9915921 100644
--- a/gdb/i386-netbsd-tdep.c
+++ b/gdb/i386-netbsd-tdep.c
@@ -372,7 +372,7 @@ i386nbsd_sigtramp_cache_init (const struct tramp_frame *self,
 static void 
 i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Obviously NetBSD is BSD-based.  */
   i386bsd_init_abi (info, gdbarch);
@@ -407,7 +407,7 @@ i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 static void
 i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* It's still NetBSD.  */
   i386nbsd_init_abi (info, gdbarch);
diff --git a/gdb/i386-nto-tdep.c b/gdb/i386-nto-tdep.c
index 11e05e3..4d443e6 100644
--- a/gdb/i386-nto-tdep.c
+++ b/gdb/i386-nto-tdep.c
@@ -77,7 +77,7 @@ static void
 i386nto_supply_gregset (struct regcache *regcache, char *gpregs)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (tdep->gregset_reg_offset == i386nto_gregset_reg_offset);
   i386_gregset.supply_regset (&i386_gregset, regcache, -1,
@@ -126,7 +126,7 @@ static int
 i386nto_register_area (struct gdbarch *gdbarch,
 		       int regno, int regset, unsigned *off)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   *off = 0;
   if (regset == NTO_REG_GENERAL)
@@ -315,7 +315,7 @@ init_i386nto_ops (void)
 static void
 i386nto_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   static struct target_so_ops nto_svr4_so_ops;
 
   /* Deal with our strange signals.  */
diff --git a/gdb/i386-obsd-tdep.c b/gdb/i386-obsd-tdep.c
index 3f5606d..ad0a7c8 100644
--- a/gdb/i386-obsd-tdep.c
+++ b/gdb/i386-obsd-tdep.c
@@ -407,7 +407,7 @@ static const struct frame_unwind i386obsd_trapframe_unwind = {
 static void 
 i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Obviously OpenBSD is BSD-based.  */
   i386bsd_init_abi (info, gdbarch);
diff --git a/gdb/i386-sol2-tdep.c b/gdb/i386-sol2-tdep.c
index acc85ee..e06ef36 100644
--- a/gdb/i386-sol2-tdep.c
+++ b/gdb/i386-sol2-tdep.c
@@ -65,7 +65,7 @@ i386_sol2_mcontext_addr (struct frame_info *this_frame)
 static void
 i386_sol2_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Solaris is SVR4-based.  */
   i386_svr4_init_abi (info, gdbarch);
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index f65a074..ce18cf3 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -167,7 +167,7 @@ const int num_lower_zmm_regs = 16;
 static int
 i386_mmx_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int mm0_regnum = tdep->mm0_regnum;
 
   if (mm0_regnum < 0)
@@ -182,7 +182,7 @@ i386_mmx_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_byte_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   regnum -= tdep->al_regnum;
   return regnum >= 0 && regnum < tdep->num_byte_regs;
@@ -193,7 +193,7 @@ i386_byte_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_word_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   regnum -= tdep->ax_regnum;
   return regnum >= 0 && regnum < tdep->num_word_regs;
@@ -204,7 +204,7 @@ i386_word_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_dword_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int eax_regnum = tdep->eax_regnum;
 
   if (eax_regnum < 0)
@@ -219,7 +219,7 @@ i386_dword_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_zmmh_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int zmm0h_regnum = tdep->zmm0h_regnum;
 
   if (zmm0h_regnum < 0)
@@ -232,7 +232,7 @@ i386_zmmh_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_zmm_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int zmm0_regnum = tdep->zmm0_regnum;
 
   if (zmm0_regnum < 0)
@@ -245,7 +245,7 @@ i386_zmm_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_k_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int k0_regnum = tdep->k0_regnum;
 
   if (k0_regnum < 0)
@@ -258,7 +258,7 @@ i386_k_regnum_p (struct gdbarch *gdbarch, int regnum)
 static int
 i386_ymmh_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ymm0h_regnum = tdep->ymm0h_regnum;
 
   if (ymm0h_regnum < 0)
@@ -273,7 +273,7 @@ i386_ymmh_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_ymm_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ymm0_regnum = tdep->ymm0_regnum;
 
   if (ymm0_regnum < 0)
@@ -286,7 +286,7 @@ i386_ymm_regnum_p (struct gdbarch *gdbarch, int regnum)
 static int
 i386_ymmh_avx512_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ymm16h_regnum = tdep->ymm16h_regnum;
 
   if (ymm16h_regnum < 0)
@@ -299,7 +299,7 @@ i386_ymmh_avx512_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_ymm_avx512_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ymm16_regnum = tdep->ymm16_regnum;
 
   if (ymm16_regnum < 0)
@@ -314,7 +314,7 @@ i386_ymm_avx512_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_bnd_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int bnd0_regnum = tdep->bnd0_regnum;
 
   if (bnd0_regnum < 0)
@@ -329,7 +329,7 @@ i386_bnd_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_xmm_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int num_xmm_regs = I387_NUM_XMM_REGS (tdep);
 
   if (num_xmm_regs == 0)
@@ -344,7 +344,7 @@ i386_xmm_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_xmm_avx512_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int num_xmm_avx512_regs = I387_NUM_XMM_AVX512_REGS (tdep);
 
   if (num_xmm_avx512_regs == 0)
@@ -357,7 +357,7 @@ i386_xmm_avx512_regnum_p (struct gdbarch *gdbarch, int regnum)
 static int
 i386_mxcsr_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (I387_NUM_XMM_REGS (tdep) == 0)
     return 0;
@@ -370,7 +370,7 @@ i386_mxcsr_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_fp_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (I387_ST0_REGNUM (tdep) < 0)
     return 0;
@@ -382,7 +382,7 @@ i386_fp_regnum_p (struct gdbarch *gdbarch, int regnum)
 int
 i386_fpc_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (I387_ST0_REGNUM (tdep) < 0)
     return 0;
@@ -396,7 +396,7 @@ i386_fpc_regnum_p (struct gdbarch *gdbarch, int regnum)
 static int
 i386_bndr_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
    if (I387_BND0R_REGNUM (tdep) < 0)
      return 0;
@@ -410,7 +410,7 @@ i386_bndr_regnum_p (struct gdbarch *gdbarch, int regnum)
 static int
 i386_mpx_ctrl_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
    if (I387_BNDCFGU_REGNUM (tdep) < 0)
      return 0;
@@ -424,7 +424,7 @@ i386_mpx_ctrl_regnum_p (struct gdbarch *gdbarch, int regnum)
 bool
 i386_pkru_regnum_p (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int pkru_regnum = tdep->pkru_regnum;
 
   if (pkru_regnum < 0)
@@ -460,7 +460,7 @@ i386_register_name (struct gdbarch *gdbarch, int regnum)
 const char *
 i386_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (i386_bnd_regnum_p (gdbarch, regnum))
     return i386_bnd_names[regnum - tdep->bnd0_regnum];
   if (i386_mmx_regnum_p (gdbarch, regnum))
@@ -483,7 +483,7 @@ i386_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 static int
 i386_dbx_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* This implements what GCC calls the "default" register map
      (dbx_register_map[]).  */
@@ -530,7 +530,7 @@ i386_dbx_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 static int
 i386_svr4_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* This implements the GCC register map that tries to be compatible
      with the SVR4 C compiler for DWARF (svr4_dbx_register_map[]).  */
@@ -2432,7 +2432,7 @@ static struct i386_frame_cache *
 i386_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct i386_frame_cache *cache;
   CORE_ADDR addr;
@@ -2521,7 +2521,8 @@ i386_sigtramp_frame_sniffer (const struct frame_unwind *self,
 			     struct frame_info *this_frame,
 			     void **this_prologue_cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* We shouldn't even bother if we don't have a sigcontext_addr
      handler.  */
@@ -2608,7 +2609,8 @@ i386_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
   CORE_ADDR sp, jb_addr;
   struct gdbarch *gdbarch = get_frame_arch (frame);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  int jb_pc_offset = gdbarch_tdep (gdbarch)->jb_pc_offset;
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int jb_pc_offset = tdep->jb_pc_offset;
 
   /* If JB_PC_OFFSET is -1, we have no way to find out where the
      longjmp will land.  */
@@ -2815,7 +2817,7 @@ static void
 i386_extract_return_value (struct gdbarch *gdbarch, struct type *type,
 			   struct regcache *regcache, gdb_byte *valbuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int len = TYPE_LENGTH (type);
   gdb_byte buf[I386_MAX_REGISTER_SIZE];
 
@@ -2873,7 +2875,7 @@ static void
 i386_store_return_value (struct gdbarch *gdbarch, struct type *type,
 			 struct regcache *regcache, const gdb_byte *valbuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int len = TYPE_LENGTH (type);
 
   if (type->code () == TYPE_CODE_FLT)
@@ -2952,7 +2954,7 @@ static const char *struct_convention = default_struct_convention;
 static int
 i386_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum type_code code = type->code ();
   int len = TYPE_LENGTH (type);
 
@@ -3054,7 +3056,7 @@ i386_return_value (struct gdbarch *gdbarch, struct value *function,
 struct type *
 i387_ext_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->i387_ext_type)
     {
@@ -3072,7 +3074,7 @@ i387_ext_type (struct gdbarch *gdbarch)
 static struct type *
 i386_bnd_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
 
   if (!tdep->i386_bnd_type)
@@ -3108,7 +3110,7 @@ i386_bnd_type (struct gdbarch *gdbarch)
 static struct type *
 i386_zmm_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->i386_zmm_type)
     {
@@ -3167,7 +3169,7 @@ i386_zmm_type (struct gdbarch *gdbarch)
 static struct type *
 i386_ymm_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->i386_ymm_type)
     {
@@ -3224,7 +3226,7 @@ i386_ymm_type (struct gdbarch *gdbarch)
 static struct type *
 i386_mmx_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->i386_mmx_type)
     {
@@ -3300,7 +3302,8 @@ i386_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
 static int
 i386_mmx_regnum_to_fp_regnum (readable_regcache *regcache, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
   int mmxreg, fpreg;
   ULONGEST fstat;
   int tos;
@@ -3341,7 +3344,7 @@ i386_pseudo_register_read_into_value (struct gdbarch *gdbarch,
     }
   else
     {
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       if (i386_bnd_regnum_p (gdbarch, regnum))
 	{
 	  regnum -= tdep->bnd0_regnum;
@@ -3531,7 +3534,7 @@ i386_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
     }
   else
     {
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
       if (i386_bnd_regnum_p (gdbarch, regnum))
 	{
@@ -3639,7 +3642,7 @@ int
 i386_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				 struct agent_expr *ax, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (i386_mmx_regnum_p (gdbarch, regnum))
     {
@@ -3856,7 +3859,7 @@ i386_supply_gregset (const struct regset *regset, struct regcache *regcache,
 		     int regnum, const void *gregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const gdb_byte *regs = (const gdb_byte *) gregs;
   int i;
 
@@ -3881,7 +3884,7 @@ i386_collect_gregset (const struct regset *regset,
 		      int regnum, void *gregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_byte *regs = (gdb_byte *) gregs;
   int i;
 
@@ -3904,7 +3907,7 @@ i386_supply_fpregset (const struct regset *regset, struct regcache *regcache,
 		      int regnum, const void *fpregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (len == I387_SIZEOF_FXSAVE)
     {
@@ -3927,7 +3930,7 @@ i386_collect_fpregset (const struct regset *regset,
 		       int regnum, void *fpregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (len == I387_SIZEOF_FXSAVE)
     {
@@ -3959,7 +3962,7 @@ i386_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				   void *cb_data,
 				   const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", tdep->sizeof_gregset, tdep->sizeof_gregset, &i386_gregset, NULL,
       cb_data);
@@ -4464,7 +4467,7 @@ i386_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 void
 i386_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* System V Release 4 uses ELF.  */
   i386_elf_init_abi (info, gdbarch);
@@ -4513,7 +4516,7 @@ int
 i386_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 			  struct reggroup *group)
 {
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int fp_regnum_p, mmx_regnum_p, xmm_regnum_p, mxcsr_regnum_p,
       ymm_regnum_p, ymmh_regnum_p, ymm_avx512_regnum_p, ymmh_avx512_regnum_p,
       bndr_regnum_p, bnd_regnum_p, zmm_regnum_p, zmmh_regnum_p,
@@ -4958,7 +4961,7 @@ static int i386_record_floats (struct gdbarch *gdbarch,
 			       struct i386_record_s *ir,
 			       uint32_t iregnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int i;
 
   /* Oza: Because of floating point insn push/pop of fpu stack is going to
@@ -5029,7 +5032,7 @@ i386_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
   ULONGEST addr;
   gdb_byte buf[I386_MAX_REGISTER_SIZE];
   struct i386_record_s ir;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   uint8_t rex_w = -1;
   uint8_t rex_r = 0;
 
@@ -8191,7 +8194,7 @@ i386_floatformat_for_type (struct gdbarch *gdbarch,
 }
 
 static int
-i386_validate_tdesc_p (struct gdbarch_tdep *tdep,
+i386_validate_tdesc_p (i386_gdbarch_tdep *tdep,
 		       struct tdesc_arch_data *tdesc_data)
 {
   const struct target_desc *tdesc = tdep->tdesc;
@@ -8393,7 +8396,6 @@ i386_type_align (struct gdbarch *gdbarch, struct type *type)
 static struct gdbarch *
 i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
   const struct target_desc *tdesc;
   int mm0_regnum;
@@ -8407,7 +8409,7 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Allocate space for the new architecture.  Assume i386 for now.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  i386_gdbarch_tdep *tdep = new i386_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* General-purpose registers.  */
@@ -8651,7 +8653,7 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   if (!i386_validate_tdesc_p (tdep, tdesc_data.get ()))
     {
-      xfree (tdep);
+      delete tdep;
       gdbarch_free (gdbarch);
       return NULL;
     }
@@ -8784,12 +8786,12 @@ static unsigned long
 i386_mpx_bd_base (void)
 {
   struct regcache *rcache;
-  struct gdbarch_tdep *tdep;
   ULONGEST ret;
   enum register_status regstatus;
 
   rcache = get_current_regcache ();
-  tdep = gdbarch_tdep (rcache->arch ());
+  gdbarch *arch = rcache->arch ();
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
 
   regstatus = regcache_raw_read_unsigned (rcache, tdep->bndcfgu_regnum, &ret);
 
@@ -8802,7 +8804,8 @@ i386_mpx_bd_base (void)
 int
 i386_mpx_enabled (void)
 {
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (get_current_arch ());
+  gdbarch *arch = get_current_arch ();
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
   const struct target_desc *tdesc = tdep->tdesc;
 
   return (tdesc_find_feature (tdesc, "org.gnu.gdb.i386.mpx") != NULL);
diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
index ee7655e..8f1819b 100644
--- a/gdb/i386-tdep.h
+++ b/gdb/i386-tdep.h
@@ -57,206 +57,206 @@ enum struct_return
 };
 
 /* i386 architecture specific information.  */
-struct gdbarch_tdep
+struct i386_gdbarch_tdep : gdbarch_tdep
 {
   /* General-purpose registers.  */
-  int *gregset_reg_offset;
-  int gregset_num_regs;
-  size_t sizeof_gregset;
+  int *gregset_reg_offset = 0;
+  int gregset_num_regs = 0;
+  size_t sizeof_gregset = 0;
 
   /* Floating-point registers.  */
-  size_t sizeof_fpregset;
+  size_t sizeof_fpregset = 0;
 
   /* Register number for %st(0).  The register numbers for the other
      registers follow from this one.  Set this to -1 to indicate the
      absence of an FPU.  */
-  int st0_regnum;
+  int st0_regnum = 0;
 
   /* Number of MMX registers.  */
-  int num_mmx_regs;
+  int num_mmx_regs = 0;
 
   /* Register number for %mm0.  Set this to -1 to indicate the absence
      of MMX support.  */
-  int mm0_regnum;
+  int mm0_regnum = 0;
 
   /* Number of pseudo YMM registers.  */
-  int num_ymm_regs;
+  int num_ymm_regs = 0;
 
   /* Register number for %ymm0.  Set this to -1 to indicate the absence
      of pseudo YMM register support.  */
-  int ymm0_regnum;
+  int ymm0_regnum = 0;
 
   /* Number of AVX512 OpMask registers (K-registers)  */
-  int num_k_regs;
+  int num_k_regs = 0;
 
   /* Register number for %k0.  Set this to -1 to indicate the absence
      of AVX512 OpMask register support.  */
-  int k0_regnum;
+  int k0_regnum = 0;
 
   /* Number of pseudo ZMM registers ($zmm0-$zmm31).  */
-  int num_zmm_regs;
+  int num_zmm_regs = 0;
 
   /* Register number for %zmm0.  Set this to -1 to indicate the absence
      of pseudo ZMM register support.  */
-  int zmm0_regnum;
+  int zmm0_regnum = 0;
 
   /* Number of byte registers.  */
-  int num_byte_regs;
+  int num_byte_regs = 0;
 
   /* Register pseudo number for %al.  */
-  int al_regnum;
+  int al_regnum = 0;
 
   /* Number of pseudo word registers.  */
-  int num_word_regs;
+  int num_word_regs = 0;
 
   /* Register number for %ax.  */
-  int ax_regnum;
+  int ax_regnum = 0;
 
   /* Number of pseudo dword registers.  */
-  int num_dword_regs;
+  int num_dword_regs = 0;
 
   /* Register number for %eax.  Set this to -1 to indicate the absence
      of pseudo dword register support.  */
-  int eax_regnum;
+  int eax_regnum = 0;
 
   /* Number of core registers.  */
-  int num_core_regs;
+  int num_core_regs = 0;
 
   /* Number of SSE registers.  */
-  int num_xmm_regs;
+  int num_xmm_regs = 0;
 
   /* Number of SSE registers added in AVX512.  */
-  int num_xmm_avx512_regs;
+  int num_xmm_avx512_regs = 0;
 
   /* Register number of XMM16, the first XMM register added in AVX512.  */
-  int xmm16_regnum;
+  int xmm16_regnum = 0;
 
   /* Number of YMM registers added in AVX512.  */
-  int num_ymm_avx512_regs;
+  int num_ymm_avx512_regs = 0;
 
   /* Register number of YMM16, the first YMM register added in AVX512.  */
-  int ymm16_regnum;
+  int ymm16_regnum = 0;
 
   /* Bits of the extended control register 0 (the XFEATURE_ENABLED_MASK
      register), excluding the x87 bit, which are supported by this GDB.  */
 
-  uint64_t xcr0;
+  uint64_t xcr0 = 0;
 
   /* Offset of XCR0 in XSAVE extended state.  */
-  int xsave_xcr0_offset;
+  int xsave_xcr0_offset = 0;
 
   /* Register names.  */
-  const char * const *register_names;
+  const char * const *register_names = nullptr;
 
   /* Register number for %ymm0h.  Set this to -1 to indicate the absence
      of upper YMM register support.  */
-  int ymm0h_regnum;
+  int ymm0h_regnum = 0;
 
   /* Upper YMM register names.  Only used for tdesc_numbered_register.  */
-  const char * const *ymmh_register_names;
+  const char * const *ymmh_register_names = nullptr;
 
   /* Register number for %ymm16h.  Set this to -1 to indicate the absence
   of support for YMM16-31.  */
-  int ymm16h_regnum;
+  int ymm16h_regnum = 0;
 
   /* YMM16-31 register names.  Only used for tdesc_numbered_register.  */
-  const char * const *ymm16h_register_names;
+  const char * const *ymm16h_register_names = nullptr;
 
   /* Register number for %bnd0r.  Set this to -1 to indicate the absence
      bound registers.  */
-  int bnd0r_regnum;
+  int bnd0r_regnum = 0;
 
   /* Register number for pseudo register %bnd0.  Set this to -1 to indicate the absence
      bound registers.  */
-  int bnd0_regnum;
+  int bnd0_regnum = 0;
 
   /* Register number for %bndcfgu. Set this to -1 to indicate the absence
      bound control registers.  */
-  int bndcfgu_regnum;
+  int bndcfgu_regnum = 0;
 
   /* MPX register names.  Only used for tdesc_numbered_register.  */
-  const char * const *mpx_register_names;
+  const char * const *mpx_register_names = nullptr;
 
   /* Register number for %zmm0h.  Set this to -1 to indicate the absence
      of ZMM_HI256 register support.  */
-  int zmm0h_regnum;
+  int zmm0h_regnum = 0;
 
   /* OpMask register names.  */
-  const char * const *k_register_names;
+  const char * const *k_register_names = nullptr;
 
   /* ZMM register names.  Only used for tdesc_numbered_register.  */
-  const char * const *zmmh_register_names;
+  const char * const *zmmh_register_names = nullptr;
 
   /* XMM16-31 register names.  Only used for tdesc_numbered_register.  */
-  const char * const *xmm_avx512_register_names;
+  const char * const *xmm_avx512_register_names = nullptr;
 
   /* YMM16-31 register names.  Only used for tdesc_numbered_register.  */
-  const char * const *ymm_avx512_register_names;
+  const char * const *ymm_avx512_register_names = nullptr;
 
   /* Number of PKEYS registers.  */
-  int num_pkeys_regs;
+  int num_pkeys_regs = 0;
 
   /* Register number for PKRU register.  */
-  int pkru_regnum;
+  int pkru_regnum = 0;
 
   /* PKEYS register names.  */
-  const char * const *pkeys_register_names;
+  const char * const *pkeys_register_names = nullptr;
 
   /* Register number for %fsbase.  Set this to -1 to indicate the
      absence of segment base registers.  */
-  int fsbase_regnum;
+  int fsbase_regnum = 0;
 
   /* Target description.  */
-  const struct target_desc *tdesc;
+  const struct target_desc *tdesc = nullptr;
 
   /* Register group function.  */
-  gdbarch_register_reggroup_p_ftype *register_reggroup_p;
+  gdbarch_register_reggroup_p_ftype *register_reggroup_p = nullptr;
 
   /* Offset of saved PC in jmp_buf.  */
-  int jb_pc_offset;
+  int jb_pc_offset = 0;
 
   /* Convention for returning structures.  */
-  enum struct_return struct_return;
+  enum struct_return struct_return {};
 
   /* Address range where sigtramp lives.  */
-  CORE_ADDR sigtramp_start;
-  CORE_ADDR sigtramp_end;
+  CORE_ADDR sigtramp_start = 0;
+  CORE_ADDR sigtramp_end = 0;
 
   /* Detect sigtramp.  */
-  int (*sigtramp_p) (struct frame_info *);
+  int (*sigtramp_p) (struct frame_info *) = nullptr;
 
   /* Get address of sigcontext for sigtramp.  */
-  CORE_ADDR (*sigcontext_addr) (struct frame_info *);
+  CORE_ADDR (*sigcontext_addr) (struct frame_info *) = nullptr;
 
   /* Offset of registers in `struct sigcontext'.  */
-  int *sc_reg_offset;
-  int sc_num_regs;
+  int *sc_reg_offset = 0;
+  int sc_num_regs = 0;
 
   /* Offset of saved PC and SP in `struct sigcontext'.  Usage of these
      is deprecated, please use `sc_reg_offset' instead.  */
-  int sc_pc_offset;
-  int sc_sp_offset;
+  int sc_pc_offset = 0;
+  int sc_sp_offset = 0;
 
   /* ISA-specific data types.  */
-  struct type *i386_mmx_type;
-  struct type *i386_ymm_type;
-  struct type *i386_zmm_type;
-  struct type *i387_ext_type;
-  struct type *i386_bnd_type;
+  struct type *i386_mmx_type = nullptr;
+  struct type *i386_ymm_type = nullptr;
+  struct type *i386_zmm_type = nullptr;
+  struct type *i387_ext_type = nullptr;
+  struct type *i386_bnd_type = nullptr;
 
   /* Process record/replay target.  */
   /* The map for registers because the AMD64's registers order
      in GDB is not same as I386 instructions.  */
-  const int *record_regmap;
+  const int *record_regmap = nullptr;
   /* Parse intx80 args.  */
-  int (*i386_intx80_record) (struct regcache *regcache);
+  int (*i386_intx80_record) (struct regcache *regcache) = nullptr;
   /* Parse sysenter args.  */
-  int (*i386_sysenter_record) (struct regcache *regcache);
+  int (*i386_sysenter_record) (struct regcache *regcache) = nullptr;
   /* Parse syscall args.  */
-  int (*i386_syscall_record) (struct regcache *regcache);
+  int (*i386_syscall_record) (struct regcache *regcache) = nullptr;
 
   /* Regsets. */
-  const struct regset *fpregset;
+  const struct regset *fpregset = nullptr;
 };
 
 /* Floating-point registers.  */
diff --git a/gdb/i386-windows-tdep.c b/gdb/i386-windows-tdep.c
index b561d60..5ab1474 100644
--- a/gdb/i386-windows-tdep.c
+++ b/gdb/i386-windows-tdep.c
@@ -136,7 +136,7 @@ i386_windows_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 static void
 i386_windows_init_abi_common (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   set_gdbarch_skip_trampoline_code (gdbarch, i386_windows_skip_trampoline_code);
 
diff --git a/gdb/i387-tdep.c b/gdb/i387-tdep.c
index cb1aa15..e5c7814 100644
--- a/gdb/i387-tdep.c
+++ b/gdb/i387-tdep.c
@@ -204,7 +204,7 @@ void
 i387_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
 		       struct frame_info *frame, const char *args)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (frame));
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST fctrl;
   int fctrl_p;
   ULONGEST fstat;
@@ -440,7 +440,7 @@ void
 i387_supply_fsave (struct regcache *regcache, int regnum, const void *fsave)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   const gdb_byte *regs = (const gdb_byte *) fsave;
   int i;
@@ -494,7 +494,8 @@ i387_supply_fsave (struct regcache *regcache, int regnum, const void *fsave)
 void
 i387_collect_fsave (const struct regcache *regcache, int regnum, void *fsave)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
   gdb_byte *regs = (gdb_byte *) fsave;
   int i;
 
@@ -587,7 +588,8 @@ static int i387_tag (const gdb_byte *raw);
 void
 i387_supply_fxsave (struct regcache *regcache, int regnum, const void *fxsave)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
   const gdb_byte *regs = (const gdb_byte *) fxsave;
   int i;
 
@@ -670,7 +672,8 @@ i387_supply_fxsave (struct regcache *regcache, int regnum, const void *fxsave)
 void
 i387_collect_fxsave (const struct regcache *regcache, int regnum, void *fxsave)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
   gdb_byte *regs = (gdb_byte *) fxsave;
   int i;
 
@@ -903,7 +906,7 @@ i387_xsave_get_clear_bv (struct gdbarch *gdbarch, const void *xsave)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   const gdb_byte *regs = (const gdb_byte *) xsave;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Get `xstat_bv'.  The supported bits in `xstat_bv' are 8 bytes.  */
   ULONGEST xstate_bv = extract_unsigned_integer (XSAVE_XSTATE_BV_ADDR (regs),
@@ -923,7 +926,7 @@ i387_supply_xsave (struct regcache *regcache, int regnum,
 {
   struct gdbarch *gdbarch = regcache->arch ();
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const gdb_byte *regs = (const gdb_byte *) xsave;
   int i;
   /* In 64-bit mode the split between "low" and "high" ZMM registers is at
@@ -1346,7 +1349,7 @@ i387_collect_xsave (const struct regcache *regcache, int regnum,
 {
   struct gdbarch *gdbarch = regcache->arch ();
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_byte *p, *regs = (gdb_byte *) xsave;
   gdb_byte raw[I386_MAX_REGISTER_SIZE];
   ULONGEST initial_xstate_bv, clear_bv, xstate_bv = 0;
@@ -1931,7 +1934,7 @@ i387_tag (const gdb_byte *raw)
 void
 i387_return_value (struct gdbarch *gdbarch, struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST fstat;
 
   /* Set the top of the floating-point register stack to 7.  The
@@ -1954,7 +1957,7 @@ i387_return_value (struct gdbarch *gdbarch, struct regcache *regcache)
 void
 i387_reset_bnd_regs (struct gdbarch *gdbarch, struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (I387_BND0R_REGNUM (tdep) > 0)
     {
diff --git a/gdb/ia64-linux-tdep.c b/gdb/ia64-linux-tdep.c
index 71767dd..cf062f1 100644
--- a/gdb/ia64-linux-tdep.c
+++ b/gdb/ia64-linux-tdep.c
@@ -216,7 +216,7 @@ ia64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 static void
 ia64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ia64_gdbarch_tdep *tdep = (ia64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   static const char *const stap_register_prefixes[] = { "r", NULL };
   static const char *const stap_register_indirection_prefixes[] = { "[",
 								    NULL };
diff --git a/gdb/ia64-tdep.c b/gdb/ia64-tdep.c
index b6816cb..08c5d6a 100644
--- a/gdb/ia64-tdep.c
+++ b/gdb/ia64-tdep.c
@@ -310,7 +310,7 @@ static const struct floatformat *floatformats_ia64_ext[2] =
 static struct type *
 ia64_ext_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ia64_gdbarch_tdep *tdep = (ia64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->ia64_ext_type)
     tdep->ia64_ext_type
@@ -2177,7 +2177,7 @@ ia64_sigtramp_frame_init_saved_regs (struct frame_info *this_frame,
 				     struct ia64_frame_cache *cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ia64_gdbarch_tdep *tdep = (ia64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->sigcontext_register_address)
     {
@@ -2335,7 +2335,8 @@ ia64_sigtramp_frame_sniffer (const struct frame_unwind *self,
 			     struct frame_info *this_frame,
 			     void **this_cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  ia64_gdbarch_tdep *tdep = (ia64_gdbarch_tdep *) gdbarch_tdep (arch);
   if (tdep->pc_in_sigtramp)
     {
       CORE_ADDR pc = get_frame_pc (this_frame);
@@ -3482,7 +3483,7 @@ ia64_find_global_pointer_from_dynamic_section (struct gdbarch *gdbarch,
 static CORE_ADDR
 ia64_find_global_pointer (struct gdbarch *gdbarch, CORE_ADDR faddr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ia64_gdbarch_tdep *tdep = (ia64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR addr = 0;
 
   if (tdep->find_global_pointer_from_solib)
@@ -3677,7 +3678,7 @@ ia64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		      function_call_return_method return_method,
 		      CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ia64_gdbarch_tdep *tdep = (ia64_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int argno;
   struct value *arg;
@@ -3917,14 +3918,13 @@ static struct gdbarch *
 ia64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* If there is already a candidate, use it.  */
   arches = gdbarch_list_lookup_by_info (arches, &info);
   if (arches != NULL)
     return arches->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  ia64_gdbarch_tdep *tdep = new ia64_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   tdep->size_of_register_frame = ia64_size_of_register_frame;
diff --git a/gdb/ia64-tdep.h b/gdb/ia64-tdep.h
index 28bf446..82319d5 100644
--- a/gdb/ia64-tdep.h
+++ b/gdb/ia64-tdep.h
@@ -20,6 +20,8 @@
 #ifndef IA64_TDEP_H
 #define IA64_TDEP_H
 
+#include "gdbarch.h"
+
 #ifdef HAVE_LIBUNWIND_IA64_H
 #include "libunwind-ia64.h"
 #include "ia64-libunwind-tdep.h"
@@ -214,30 +216,33 @@ struct ia64_infcall_ops
 
      Should do nothing if this operation is not permitted by the OS.  */
   void (*allocate_new_rse_frame) (struct regcache *regcache, ULONGEST bsp,
-				  int sof);
+				  int sof) = nullptr;
 
   /* Store the argument stored in BUF into the appropriate location
      given the BSP and the SLOTNUM.  */
   void (*store_argument_in_slot) (struct regcache *regcache, CORE_ADDR bsp,
-				  int slotnum, gdb_byte *buf);
+				  int slotnum, gdb_byte *buf) = nullptr;
 
   /* For targets where we cannot call the function directly, store
      the address of the function we want to call at the location
      expected by the calling sequence.  */
-  void (*set_function_addr) (struct regcache *regcache, CORE_ADDR func_addr);
+  void (*set_function_addr) (struct regcache *regcache, CORE_ADDR func_addr)
+    = nullptr;
 };
 
-struct gdbarch_tdep
+struct ia64_gdbarch_tdep : gdbarch_tdep
 {
-  CORE_ADDR (*sigcontext_register_address) (struct gdbarch *, CORE_ADDR, int);
-  int (*pc_in_sigtramp) (CORE_ADDR);
+  CORE_ADDR (*sigcontext_register_address) (struct gdbarch *, CORE_ADDR, int)
+    = nullptr;
+  int (*pc_in_sigtramp) (CORE_ADDR) = nullptr;
 
   /* Return the total size of THIS_FRAME's register frame.
      CFM is THIS_FRAME's cfm register value.
 
      Normally, the size of the register frame is always obtained by
      extracting the lowest 7 bits ("cfm & 0x7f").  */
-  int (*size_of_register_frame) (struct frame_info *this_frame, ULONGEST cfm);
+  int (*size_of_register_frame) (struct frame_info *this_frame, ULONGEST cfm)
+    = nullptr;
 
   /* Determine the function address FADDR belongs to a shared library.
      If it does, then return the associated global pointer.  If no shared
@@ -245,10 +250,10 @@ struct gdbarch_tdep
 
      This pointer may be NULL.  */
   CORE_ADDR (*find_global_pointer_from_solib) (struct gdbarch *gdbarch,
-					       CORE_ADDR faddr);
+					       CORE_ADDR faddr) = nullptr;
 
   /* ISA-specific data types.  */
-  struct type *ia64_ext_type;
+  struct type *ia64_ext_type = nullptr;
 
   struct ia64_infcall_ops infcall_ops;
 };
diff --git a/gdb/lm32-tdep.c b/gdb/lm32-tdep.c
index 9c5dda3..3f91c05 100644
--- a/gdb/lm32-tdep.c
+++ b/gdb/lm32-tdep.c
@@ -42,7 +42,7 @@
 #define LM32_REG2(insn)         ((insn >> 11) & 0x1f)
 #define LM32_IMM16(insn)        ((((long)insn & 0xffff) << 16) >> 16)
 
-struct gdbarch_tdep
+struct lm32_gdbarch_tdep : gdbarch_tdep
 {
   /* gdbarch target dependent data here.  Currently unused for LM32.  */
 };
@@ -491,7 +491,6 @@ static struct gdbarch *
 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* If there is already a candidate, use it.  */
   arches = gdbarch_list_lookup_by_info (arches, &info);
@@ -499,7 +498,7 @@ lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* None found, create a new architecture from the information provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  lm32_gdbarch_tdep *tdep = new lm32_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Type sizes.  */
diff --git a/gdb/m32c-tdep.c b/gdb/m32c-tdep.c
index 3374b00..200d51a 100644
--- a/gdb/m32c-tdep.c
+++ b/gdb/m32c-tdep.c
@@ -95,42 +95,44 @@ struct m32c_reg
 #define M32C_MAX_DWARF_REGNUM (40)
 
 
-struct gdbarch_tdep
+struct m32c_gdbarch_tdep : gdbarch_tdep
 {
   /* All the registers for this variant, indexed by GDB register
      number, and the number of registers present.  */
-  struct m32c_reg regs[M32C_MAX_NUM_REGS];
+  struct m32c_reg regs[M32C_MAX_NUM_REGS] {};
 
   /* The number of valid registers.  */
-  int num_regs;
+  int num_regs = 0;
 
   /* Interesting registers.  These are pointers into REGS.  */
-  struct m32c_reg *pc, *flg;
-  struct m32c_reg *r0, *r1, *r2, *r3, *a0, *a1;
-  struct m32c_reg *r2r0, *r3r2r1r0, *r3r1r2r0;
-  struct m32c_reg *sb, *fb, *sp;
+  struct m32c_reg *pc = nullptr, *flg = nullptr;
+  struct m32c_reg *r0 = nullptr, *r1 = nullptr, *r2 = nullptr, *r3 = nullptr,
+    *a0 = nullptr, *a1 = nullptr;
+  struct m32c_reg *r2r0 = nullptr, *r3r2r1r0 = nullptr, *r3r1r2r0 = nullptr;
+  struct m32c_reg *sb = nullptr, *fb = nullptr, *sp = nullptr;
 
   /* A table indexed by DWARF register numbers, pointing into
      REGS.  */
-  struct m32c_reg *dwarf_regs[M32C_MAX_DWARF_REGNUM + 1];
+  struct m32c_reg *dwarf_regs[M32C_MAX_DWARF_REGNUM + 1] {};
 
   /* Types for this architecture.  We can't use the builtin_type_foo
      types, because they're not initialized when building a gdbarch
      structure.  */
-  struct type *voyd, *ptr_voyd, *func_voyd;
-  struct type *uint8, *uint16;
-  struct type *int8, *int16, *int32, *int64;
+  struct type *voyd = nullptr, *ptr_voyd = nullptr, *func_voyd = nullptr;
+  struct type *uint8 = nullptr, *uint16 = nullptr;
+  struct type *int8 = nullptr, *int16 = nullptr, *int32 = nullptr,
+    *int64 = nullptr;
 
   /* The types for data address and code address registers.  */
-  struct type *data_addr_reg_type, *code_addr_reg_type;
+  struct type *data_addr_reg_type = nullptr, *code_addr_reg_type = nullptr;
 
   /* The number of bytes a return address pushed by a 'jsr' instruction
      occupies on the stack.  */
-  int ret_addr_bytes;
+  int ret_addr_bytes = 0;
 
   /* The number of bytes an address register occupies on the stack
      when saved by an 'enter' or 'pushm' instruction.  */
-  int push_addr_bytes;
+  int push_addr_bytes = 0;
 };
 
 
@@ -139,7 +141,7 @@ struct gdbarch_tdep
 static void
 make_types (struct gdbarch *arch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   unsigned long mach = gdbarch_bfd_arch_info (arch)->mach;
   int data_addr_reg_bits, code_addr_reg_bits;
   char type_name[50];
@@ -212,28 +214,31 @@ make_types (struct gdbarch *arch)
 static const char *
 m32c_register_name (struct gdbarch *gdbarch, int num)
 {
-  return gdbarch_tdep (gdbarch)->regs[num].name;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->regs[num].name;
 }
 
 
 static struct type *
 m32c_register_type (struct gdbarch *arch, int reg_nr)
 {
-  return gdbarch_tdep (arch)->regs[reg_nr].type;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->regs[reg_nr].type;
 }
 
 
 static int
 m32c_register_sim_regno (struct gdbarch *gdbarch, int reg_nr)
 {
-  return gdbarch_tdep (gdbarch)->regs[reg_nr].sim_num;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->regs[reg_nr].sim_num;
 }
 
 
 static int
 m32c_debug_info_reg_to_regnum (struct gdbarch *gdbarch, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (0 <= reg_nr && reg_nr <= M32C_MAX_DWARF_REGNUM
       && tdep->dwarf_regs[reg_nr])
     return tdep->dwarf_regs[reg_nr]->num;
@@ -248,7 +253,7 @@ static int
 m32c_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 			  struct reggroup *group)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct m32c_reg *reg = &tdep->regs[regnum];
 
   /* The anonymous raw registers aren't in any groups.  */
@@ -323,7 +328,8 @@ m32c_raw_write (struct m32c_reg *reg, struct regcache *cache,
 static int
 m32c_read_flg (readable_regcache *cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (cache->arch ());
+  gdbarch *arch = cache->arch ();
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   ULONGEST flg;
 
   cache->raw_read (tdep->flg->num, &flg);
@@ -522,7 +528,8 @@ m32c_cat_write (struct m32c_reg *reg, struct regcache *cache,
 static enum register_status
 m32c_r3r2r1r0_read (struct m32c_reg *reg, readable_regcache *cache, gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (reg->arch);
+  gdbarch *arch = reg->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   int len = TYPE_LENGTH (tdep->r0->type);
   enum register_status status;
 
@@ -558,7 +565,8 @@ static enum register_status
 m32c_r3r2r1r0_write (struct m32c_reg *reg, struct regcache *cache,
 		     const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (reg->arch);
+  gdbarch *arch = reg->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   int len = TYPE_LENGTH (tdep->r0->type);
 
   if (gdbarch_byte_order (reg->arch) == BFD_ENDIAN_BIG)
@@ -586,7 +594,7 @@ m32c_pseudo_register_read (struct gdbarch *arch,
 			   int cookednum,
 			   gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   struct m32c_reg *reg;
 
   gdb_assert (0 <= cookednum && cookednum < tdep->num_regs);
@@ -604,7 +612,7 @@ m32c_pseudo_register_write (struct gdbarch *arch,
 			    int cookednum,
 			    const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   struct m32c_reg *reg;
 
   gdb_assert (0 <= cookednum && cookednum < tdep->num_regs);
@@ -629,7 +637,7 @@ add_reg (struct gdbarch *arch,
 	 struct m32c_reg *ry,
 	 int n)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   struct m32c_reg *r = &tdep->regs[tdep->num_regs];
 
   gdb_assert (tdep->num_regs < M32C_MAX_NUM_REGS);
@@ -668,7 +676,9 @@ set_dwarf_regnum (struct m32c_reg *reg, int num)
     reg->dwarf_num = num;
 
   /* Update the DWARF->reg mapping.  */
-  gdbarch_tdep (reg->arch)->dwarf_regs[num] = reg;
+  gdbarch *arch = reg->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
+  tdep->dwarf_regs[num] = reg;
 }
 
 
@@ -789,7 +799,7 @@ mark_save_restore (struct m32c_reg *reg)
 static void
 make_regs (struct gdbarch *arch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   int mach = gdbarch_bfd_arch_info (arch)->mach;
   int num_raw_regs;
   int num_cooked_regs;
@@ -1336,16 +1346,17 @@ m32c_decode_sd23 (struct m32c_pv_state *st, int code, int size, int ind)
 static int
 m32c_pv_enter (struct m32c_pv_state *state, int size)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
-
   /* If simulating this store would require us to forget
      everything we know about the stack frame in the name of
      accuracy, it would be better to just quit now.  */
   if (state->stack->store_would_trash (state->sp))
     return 1;
 
+  gdbarch *arch = state->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   if (m32c_pv_push (state, state->fb, tdep->push_addr_bytes))
     return 1;
+
   state->fb = state->sp;
   state->sp = pv_add_constant (state->sp, -size);
 
@@ -1371,7 +1382,8 @@ m32c_pv_pushm_one (struct m32c_pv_state *state, pv_t reg,
 static int
 m32c_pv_pushm (struct m32c_pv_state *state, int src)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+  gdbarch *arch = state->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* The bits in SRC indicating which registers to save are:
      r0 r1 r2 r3 a0 a1 sb fb */
@@ -1391,7 +1403,9 @@ m32c_pv_pushm (struct m32c_pv_state *state, int src)
 static int
 m32c_is_1st_arg_reg (struct m32c_pv_state *state, pv_t value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+  gdbarch *arch = state->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
+
   return (value.kind == pvk_register
 	  && (gdbarch_bfd_arch_info (state->arch)->mach == bfd_mach_m16c
 	      ? (value.reg == tdep->r1->num)
@@ -1404,7 +1418,9 @@ m32c_is_1st_arg_reg (struct m32c_pv_state *state, pv_t value)
 static int
 m32c_is_arg_reg (struct m32c_pv_state *state, pv_t value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (state->arch);
+  gdbarch *arch = state->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
+
   return (value.kind == pvk_register
 	  && (gdbarch_bfd_arch_info (state->arch)->mach == bfd_mach_m16c
 	      ? (value.reg == tdep->r1->num || value.reg == tdep->r2->num)
@@ -1427,7 +1443,8 @@ m32c_is_arg_spill (struct m32c_pv_state *st,
 		   struct srcdest loc, 
 		   pv_t value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (st->arch);
+  gdbarch *arch = st->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
 
   return (m32c_is_arg_reg (st, value)
 	  && loc.kind == srcdest_mem
@@ -1450,7 +1467,8 @@ m32c_is_struct_return (struct m32c_pv_state *st,
 		       struct srcdest loc, 
 		       pv_t value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (st->arch);
+  gdbarch *arch = st->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
 
   return (m32c_is_1st_arg_reg (st, value)
 	  && !st->stack->find_reg (st->arch, value.reg, 0)
@@ -1467,7 +1485,9 @@ m32c_is_struct_return (struct m32c_pv_state *st,
 static int
 m32c_pushm_is_reg_save (struct m32c_pv_state *st, int src)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (st->arch);
+  gdbarch *arch = st->arch;
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
+
   /* The bits in SRC indicating which registers to save are:
      r0 r1 r2 r3 a0 a1 sb fb */
   return
@@ -1494,7 +1514,7 @@ check_for_saved (void *prologue_untyped, pv_t addr, CORE_ADDR size, pv_t value)
 {
   struct m32c_prologue *prologue = (struct m32c_prologue *) prologue_untyped;
   struct gdbarch *arch = prologue->arch;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* Is this the unchanged value of some register being saved on the
      stack?  */
@@ -1534,7 +1554,7 @@ m32c_analyze_prologue (struct gdbarch *arch,
 		       CORE_ADDR start, CORE_ADDR limit,
 		       struct m32c_prologue *prologue)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   unsigned long mach = gdbarch_bfd_arch_info (arch)->mach;
   CORE_ADDR after_last_frame_related_insn;
   struct m32c_pv_state st;
@@ -1864,7 +1884,8 @@ m32c_frame_base (struct frame_info *this_frame,
 {
   struct m32c_prologue *p
     = m32c_analyze_frame_prologue (this_frame, this_prologue_cache);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
 
   /* In functions that use alloca, the distance between the stack
      pointer and the frame base varies dynamically, so we can't use
@@ -1914,7 +1935,8 @@ static struct value *
 m32c_prev_register (struct frame_info *this_frame,
 		    void **this_prologue_cache, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (arch);
   struct m32c_prologue *p
     = m32c_analyze_frame_prologue (this_frame, this_prologue_cache);
   CORE_ADDR frame_base = m32c_frame_base (this_frame, this_prologue_cache);
@@ -1997,7 +2019,7 @@ m32c_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		      function_call_return_method return_method,
 		      CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach;
   CORE_ADDR cfa;
@@ -2160,7 +2182,7 @@ m32c_return_value (struct gdbarch *gdbarch,
 		   gdb_byte *readbuf,
 		   const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   enum return_value_convention conv;
   ULONGEST valtype_len = TYPE_LENGTH (valtype);
@@ -2291,7 +2313,7 @@ static CORE_ADDR
 m32c_skip_trampoline_code (struct frame_info *frame, CORE_ADDR stop_pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   /* It would be nicer to simply look up the addresses of known
@@ -2537,7 +2559,7 @@ m32c_virtual_frame_pointer (struct gdbarch *gdbarch, CORE_ADDR pc,
   struct m32c_prologue p;
 
   struct regcache *regcache = get_current_regcache ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m32c_gdbarch_tdep *tdep = (m32c_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   
   if (!find_pc_partial_function (pc, &name, &func_addr, &func_end))
     internal_error (__FILE__, __LINE__,
@@ -2572,7 +2594,6 @@ static struct gdbarch *
 m32c_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   unsigned long mach = info.bfd_arch_info->mach;
 
   /* Find a candidate among the list of architectures we've created
@@ -2582,7 +2603,7 @@ m32c_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     return arches->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  m32c_gdbarch_tdep *tdep = new m32c_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Essential types.  */
diff --git a/gdb/m32r-tdep.c b/gdb/m32r-tdep.c
index 48cc42c..a9906ff 100644
--- a/gdb/m32r-tdep.c
+++ b/gdb/m32r-tdep.c
@@ -865,7 +865,6 @@ static struct gdbarch *
 m32r_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* If there is already a candidate, use it.  */
   arches = gdbarch_list_lookup_by_info (arches, &info);
@@ -873,7 +872,7 @@ m32r_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Allocate space for the new architecture.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  m32r_gdbarch_tdep *tdep = new m32r_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   set_gdbarch_wchar_bit (gdbarch, 16);
diff --git a/gdb/m32r-tdep.h b/gdb/m32r-tdep.h
index ba6bad9..22c333c 100644
--- a/gdb/m32r-tdep.h
+++ b/gdb/m32r-tdep.h
@@ -20,7 +20,9 @@
 #ifndef M32R_TDEP_H
 #define M32R_TDEP_H
 
-struct gdbarch_tdep
+#include "gdbarch.h"
+
+struct m32r_gdbarch_tdep : gdbarch_tdep
 {
   /* gdbarch target dependent data here.  Currently unused for M32R.  */
 };
diff --git a/gdb/m68hc11-tdep.c b/gdb/m68hc11-tdep.c
index bbf7e5d..6d41fe8 100644
--- a/gdb/m68hc11-tdep.c
+++ b/gdb/m68hc11-tdep.c
@@ -123,27 +123,38 @@ enum insn_return_kind {
 #define M68HC12_HARD_PC_REGNUM  (SOFT_D32_REGNUM+1)
 
 struct insn_sequence;
-struct gdbarch_tdep
+struct m68gc11_gdbarch_tdep : gdbarch_tdep
   {
     /* Stack pointer correction value.  For 68hc11, the stack pointer points
        to the next push location.  An offset of 1 must be applied to obtain
        the address where the last value is saved.  For 68hc12, the stack
        pointer points to the last value pushed.  No offset is necessary.  */
-    int stack_correction;
+    int stack_correction = 0;
 
     /* Description of instructions in the prologue.  */
-    struct insn_sequence *prologue;
+    struct insn_sequence *prologue = nullptr;
 
     /* True if the page memory bank register is available
        and must be used.  */
-    int use_page_register;
+    int use_page_register = 0;
 
     /* ELF flags for ABI.  */
-    int elf_flags;
+    int elf_flags = 0;
   };
 
-#define STACK_CORRECTION(gdbarch) (gdbarch_tdep (gdbarch)->stack_correction)
-#define USE_PAGE_REGISTER(gdbarch) (gdbarch_tdep (gdbarch)->use_page_register)
+static int
+stack_correction (gdbarch *arch)
+{
+  m68gc11_gdbarch_tdep *tdep = (m68gc11_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->stack_correction;
+}
+
+static int
+use_page_register (gdbarch *arch)
+{
+  m68gc11_gdbarch_tdep *tdep = (m68gc11_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->stack_correction;
+}
 
 struct m68hc11_unwind_cache
 {
@@ -371,13 +382,15 @@ m68hc11_pseudo_register_write (struct gdbarch *gdbarch,
 static const char *
 m68hc11_register_name (struct gdbarch *gdbarch, int reg_nr)
 {
-  if (reg_nr == M68HC12_HARD_PC_REGNUM && USE_PAGE_REGISTER (gdbarch))
+  if (reg_nr == M68HC12_HARD_PC_REGNUM && use_page_register (gdbarch))
     return "pc";
-  if (reg_nr == HARD_PC_REGNUM && USE_PAGE_REGISTER (gdbarch))
+
+  if (reg_nr == HARD_PC_REGNUM && use_page_register (gdbarch))
     return "ppc";
   
   if (reg_nr < 0)
     return NULL;
+
   if (reg_nr >= M68HC11_ALL_REGS)
     return NULL;
 
@@ -387,6 +400,7 @@ m68hc11_register_name (struct gdbarch *gdbarch, int reg_nr)
      does not exist.  */
   if (reg_nr > M68HC11_LAST_HARD_REG && soft_regs[reg_nr].name == 0)
     return NULL;
+
   return m68hc11_register_names[reg_nr];
 }
 
@@ -627,7 +641,8 @@ m68hc11_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR pc,
       return pc;
     }
 
-  seq_table = gdbarch_tdep (gdbarch)->prologue;
+  m68gc11_gdbarch_tdep *tdep = (m68gc11_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  seq_table = tdep->prologue;
   
   /* The 68hc11 stack is as follows:
 
@@ -807,7 +822,7 @@ m68hc11_frame_unwind_cache (struct frame_info *this_frame,
       info->saved_regs[HARD_PC_REGNUM].set_addr (info->sp_offset);
       this_base = get_frame_register_unsigned (this_frame, HARD_SP_REGNUM);
       prev_sp = this_base + info->sp_offset + 2;
-      this_base += STACK_CORRECTION (gdbarch);
+      this_base += stack_correction (gdbarch);
     }
   else
     {
@@ -815,7 +830,7 @@ m68hc11_frame_unwind_cache (struct frame_info *this_frame,
 	 to before the first saved register giving the SP.  */
       prev_sp = this_base + info->size + 2;
 
-      this_base += STACK_CORRECTION (gdbarch);
+      this_base += stack_correction (gdbarch);
       if (soft_regs[SOFT_FP_REGNUM].name)
 	info->saved_regs[SOFT_FP_REGNUM].set_addr (info->size - 2);
    }
@@ -898,7 +913,7 @@ m68hc11_frame_prev_register (struct frame_info *this_frame,
   /* Take into account the 68HC12 specific call (PC + page).  */
   if (regnum == HARD_PC_REGNUM
       && info->return_kind == RETURN_RTC
-      && USE_PAGE_REGISTER (get_frame_arch (this_frame)))
+      && use_page_register (get_frame_arch (this_frame)))
     {
       CORE_ADDR pc = value_as_long (value);
       if (pc >= 0x08000 && pc < 0x0c000)
@@ -1003,7 +1018,10 @@ m68hc11_print_register (struct gdbarch *gdbarch, struct ui_file *file,
     }
   else
     {
-      if (regno == HARD_PC_REGNUM && gdbarch_tdep (gdbarch)->use_page_register)
+      m68gc11_gdbarch_tdep *tdep
+	= (m68gc11_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+      if (regno == HARD_PC_REGNUM && tdep->use_page_register)
 	{
 	  ULONGEST page;
 
@@ -1106,7 +1124,9 @@ m68hc11_print_registers_info (struct gdbarch *gdbarch, struct ui_file *file,
       fprintf_filtered (file, " Y=");
       m68hc11_print_register (gdbarch, file, frame, HARD_Y_REGNUM);
   
-      if (gdbarch_tdep (gdbarch)->use_page_register)
+      m68gc11_gdbarch_tdep *tdep = (m68gc11_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+      if (tdep->use_page_register)
 	{
 	  fprintf_filtered (file, "\nPage=");
 	  m68hc11_print_register (gdbarch, file, frame, HARD_PAGE_REGNUM);
@@ -1194,7 +1214,7 @@ m68hc11_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   write_memory (sp, buf, 2);
 
   /* Finally, update the stack pointer...  */
-  sp -= STACK_CORRECTION (gdbarch);
+  sp -= stack_correction (gdbarch);
   regcache_cooked_write_unsigned (regcache, HARD_SP_REGNUM, sp);
 
   /* ...and fake a frame pointer.  */
@@ -1386,7 +1406,6 @@ m68hc11_gdbarch_init (struct gdbarch_info info,
 		      struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int elf_flags;
 
   soft_reg_initialized = 0;
@@ -1403,14 +1422,17 @@ m68hc11_gdbarch_init (struct gdbarch_info info,
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      if (gdbarch_tdep (arches->gdbarch)->elf_flags != elf_flags)
+      m68gc11_gdbarch_tdep *tdep
+	= (m68gc11_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
+      if (tdep->elf_flags != elf_flags)
 	continue;
 
       return arches->gdbarch;
     }
 
   /* Need a new architecture.  Fill in a target specific vector.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  m68gc11_gdbarch_tdep *tdep = new m68gc11_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->elf_flags = elf_flags;
 
diff --git a/gdb/m68k-bsd-tdep.c b/gdb/m68k-bsd-tdep.c
index 593708f..27fbb84 100644
--- a/gdb/m68k-bsd-tdep.c
+++ b/gdb/m68k-bsd-tdep.c
@@ -133,7 +133,7 @@ m68kbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 static void
 m68kbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->jb_pc = 5;
   tdep->jb_elt_size = 4;
diff --git a/gdb/m68k-linux-tdep.c b/gdb/m68k-linux-tdep.c
index ad4d75a..6704d83 100644
--- a/gdb/m68k-linux-tdep.c
+++ b/gdb/m68k-linux-tdep.c
@@ -384,7 +384,7 @@ m68k_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 static void
 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/m68k-tdep.c b/gdb/m68k-tdep.c
index 75fa189..4ae27e6 100644
--- a/gdb/m68k-tdep.c
+++ b/gdb/m68k-tdep.c
@@ -70,7 +70,7 @@ typedef BP_MANIPULATION (m68k_break_insn) m68k_breakpoint;
 static struct type *
 m68k_ps_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->m68k_ps_type)
     {
@@ -99,7 +99,7 @@ m68k_ps_type (struct gdbarch *gdbarch)
 static struct type *
 m68881_ext_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->m68881_ext_type)
     tdep->m68881_ext_type
@@ -120,7 +120,7 @@ m68881_ext_type (struct gdbarch *gdbarch)
 static struct type *
 m68k_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->fpregs_present)
     {
@@ -171,12 +171,14 @@ static const char * const m68k_register_names[] = {
 static const char *
 m68k_register_name (struct gdbarch *gdbarch, int regnum)
 {
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   if (regnum < 0 || regnum >= ARRAY_SIZE (m68k_register_names))
     internal_error (__FILE__, __LINE__,
 		    _("m68k_register_name: illegal register number %d"),
 		    regnum);
   else if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM
-	   && gdbarch_tdep (gdbarch)->fpregs_present == 0)
+	   && tdep->fpregs_present == 0)
     return "";
   else
     return m68k_register_names[regnum];
@@ -189,7 +191,9 @@ static int
 m68k_convert_register_p (struct gdbarch *gdbarch,
 			 int regnum, struct type *type)
 {
-  if (!gdbarch_tdep (gdbarch)->fpregs_present)
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  if (!tdep->fpregs_present)
     return 0;
   return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7
 	  /* We only support floating-point values.  */
@@ -296,7 +300,7 @@ m68k_extract_return_value (struct type *type, struct regcache *regcache,
   if (type->code () == TYPE_CODE_PTR && len == 4)
     {
       struct gdbarch *gdbarch = regcache->arch ();
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       regcache->raw_read (tdep->pointer_result_regnum, valbuf);
     }
   else if (len <= 4)
@@ -321,7 +325,7 @@ m68k_svr4_extract_return_value (struct type *type, struct regcache *regcache,
 {
   gdb_byte buf[M68K_MAX_REGISTER_SIZE];
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->float_return && type->code () == TYPE_CODE_FLT)
     {
@@ -344,7 +348,7 @@ m68k_store_return_value (struct type *type, struct regcache *regcache,
   if (type->code () == TYPE_CODE_PTR && len == 4)
     {
       struct gdbarch *gdbarch = regcache->arch ();
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       regcache->raw_write (tdep->pointer_result_regnum, valbuf);
       /* gdb historically also set D0 in the SVR4 case.  */
       if (tdep->pointer_result_regnum != M68K_D0_REGNUM)
@@ -367,7 +371,7 @@ m68k_svr4_store_return_value (struct type *type, struct regcache *regcache,
 			      const gdb_byte *valbuf)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->float_return && type->code () == TYPE_CODE_FLT)
     {
@@ -387,7 +391,7 @@ m68k_svr4_store_return_value (struct type *type, struct regcache *regcache,
 static int
 m68k_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum type_code code = type->code ();
   int len = TYPE_LENGTH (type);
 
@@ -465,6 +469,7 @@ m68k_svr4_return_value (struct gdbarch *gdbarch, struct value *function,
 			gdb_byte *readbuf, const gdb_byte *writebuf)
 {
   enum type_code code = type->code ();
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Aggregates with a single member are always returned like their
      sole element.  */
@@ -480,7 +485,7 @@ m68k_svr4_return_value (struct gdbarch *gdbarch, struct value *function,
 	|| code == TYPE_CODE_COMPLEX || code == TYPE_CODE_ARRAY)
        && !m68k_reg_struct_return_p (gdbarch, type))
       /* GCC may return a `long double' in memory too.  */
-      || (!gdbarch_tdep (gdbarch)->float_return
+      || (!tdep->float_return
 	  && code == TYPE_CODE_FLT
 	  && TYPE_LENGTH (type) == 12))
     {
@@ -500,7 +505,6 @@ m68k_svr4_return_value (struct gdbarch *gdbarch, struct value *function,
 
       if (readbuf)
 	{
-	  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 	  ULONGEST addr;
 
 	  regcache_raw_read_unsigned (regcache, tdep->pointer_result_regnum,
@@ -537,7 +541,7 @@ m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		      function_call_return_method return_method,
 		      CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   gdb_byte buf[4];
   int i;
@@ -592,13 +596,15 @@ m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 static int
 m68k_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int num)
 {
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   if (num < 8)
     /* d0..7 */
     return (num - 0) + M68K_D0_REGNUM;
   else if (num < 16)
     /* a0..7 */
     return (num - 8) + M68K_A0_REGNUM;
-  else if (num < 24 && gdbarch_tdep (gdbarch)->fpregs_present)
+  else if (num < 24 && tdep->fpregs_present)
     /* fp0..7 */
     return (num - 16) + M68K_FP0_REGNUM;
   else if (num == 25)
@@ -760,6 +766,7 @@ m68k_analyze_register_saves (struct gdbarch *gdbarch, CORE_ADDR pc,
 			     struct m68k_frame_cache *cache)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (cache->locals >= 0)
     {
@@ -772,7 +779,7 @@ m68k_analyze_register_saves (struct gdbarch *gdbarch, CORE_ADDR pc,
 	{
 	  op = read_memory_unsigned_integer (pc, 2, byte_order);
 	  if (op == P_FMOVEMX_SP
-	      && gdbarch_tdep (gdbarch)->fpregs_present)
+	      && tdep->fpregs_present)
 	    {
 	      /* fmovem.x REGS,-(%sp) */
 	      op = read_memory_unsigned_integer (pc + 2, 2, byte_order);
@@ -1051,7 +1058,7 @@ m68k_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
   gdb_byte *buf;
   CORE_ADDR sp, jb_addr;
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   if (tdep->jb_pc < 0)
@@ -1097,7 +1104,7 @@ m68k_return_in_first_hidden_param_p (struct gdbarch *gdbarch,
 void
 m68k_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* SVR4 uses a different calling convention.  */
   set_gdbarch_return_value (gdbarch, m68k_svr4_return_value);
@@ -1115,7 +1122,7 @@ m68k_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 static void
 m68k_embedded_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   m68k_svr4_init_abi (info, gdbarch);
   tdep->pointer_result_regnum = M68K_D0_REGNUM;
@@ -1130,7 +1137,6 @@ m68k_embedded_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 static struct gdbarch *
 m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep = NULL;
   struct gdbarch *gdbarch;
   struct gdbarch_list *best_arch;
   tdesc_arch_data_up tdesc_data;
@@ -1230,13 +1236,16 @@ m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch != NULL;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
-      if (flavour != gdbarch_tdep (best_arch->gdbarch)->flavour)
+      m68k_gdbarch_tdep *tdep
+	= (m68k_gdbarch_tdep *) gdbarch_tdep (best_arch->gdbarch);
+
+      if (flavour != tdep->flavour)
 	continue;
 
-      if (has_fp != gdbarch_tdep (best_arch->gdbarch)->fpregs_present)
+      if (has_fp != tdep->fpregs_present)
 	continue;
 
-      if (float_return != gdbarch_tdep (best_arch->gdbarch)->float_return)
+      if (float_return != tdep->float_return)
 	continue;
 
       break;
@@ -1245,7 +1254,7 @@ m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   if (best_arch != NULL)
     return best_arch->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  m68k_gdbarch_tdep *tdep = new m68k_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->fpregs_present = has_fp;
   tdep->float_return = float_return;
@@ -1330,7 +1339,7 @@ m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 m68k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  m68k_gdbarch_tdep *tdep = (m68k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep == NULL)
     return;
diff --git a/gdb/m68k-tdep.h b/gdb/m68k-tdep.h
index 16384d1..c88e7f2 100644
--- a/gdb/m68k-tdep.h
+++ b/gdb/m68k-tdep.h
@@ -67,38 +67,38 @@ enum m68k_flavour
 
 /* Target-dependent structure in gdbarch.  */
 
-struct gdbarch_tdep
+struct m68k_gdbarch_tdep : gdbarch_tdep
 {
   /* Offset to PC value in the jump buffer.  If this is negative,
      longjmp support will be disabled.  */
-  int jb_pc;
+  int jb_pc = 0;
   /* The size of each entry in the jump buffer.  */
-  size_t jb_elt_size;
+  size_t jb_elt_size = 0;
 
   /* Register in which the address to store a structure value is
      passed to a function.  */
-  int struct_value_regnum;
+  int struct_value_regnum = 0;
 
   /* Register in which a pointer value is returned.  In the SVR4 ABI,
      this is %a0, but in GCC's "embedded" ABI, this is %d0.  */
-  int pointer_result_regnum;
+  int pointer_result_regnum = 0;
 
   /* Convention for returning structures.  */
-  enum struct_return struct_return;
+  enum struct_return struct_return {};
 
   /* Convention for returning floats.  zero in int regs, non-zero in float.  */
-  int float_return;
+  int float_return = 0;
 
   /* The particular flavour of m68k.  */
-  enum m68k_flavour flavour;
+  enum m68k_flavour flavour {};
 
   /* Flag set if the floating point registers are present, or assumed
      to be present.  */
-  int fpregs_present;
+  int fpregs_present = 0;
 
    /* ISA-specific data types.  */
-  struct type *m68k_ps_type;
-  struct type *m68881_ext_type;
+  struct type *m68k_ps_type = nullptr;
+  struct type *m68881_ext_type = nullptr;
 };
 
 /* Initialize a SVR4 architecture variant.  */
diff --git a/gdb/mep-tdep.c b/gdb/mep-tdep.c
index d48e1f1..6d1f04a 100644
--- a/gdb/mep-tdep.c
+++ b/gdb/mep-tdep.c
@@ -116,7 +116,7 @@
      options are present on the current processor.  */
 
 
-struct gdbarch_tdep
+struct mep_gdbarch_tdep : gdbarch_tdep
 {
   /* A CGEN cpu descriptor for this BFD architecture and machine.
 
@@ -124,7 +124,7 @@ struct gdbarch_tdep
      MeP libopcodes machinery actually puts off module-specific
      customization until the last minute.  So this contains
      information about all supported me_modules.  */
-  CGEN_CPU_DESC cpu_desc;
+  CGEN_CPU_DESC cpu_desc = nullptr;
 
   /* The me_module index from the ELF file we used to select this
      architecture, or CONFIG_NONE if there was none.
@@ -140,7 +140,7 @@ struct gdbarch_tdep
      create a separate instance of the gdbarch structure for each
      me_module value mep_gdbarch_init sees, and store the me_module
      value from the ELF file here.  */
-  CONFIG_ATTR me_module;
+  CONFIG_ATTR me_module {};
 };
 
 
@@ -259,7 +259,9 @@ me_module_register_set (CONFIG_ATTR me_module,
        mask contains any of the me_module's coprocessor ISAs,
        specifically excluding the generic coprocessor register sets.  */
 
-  CGEN_CPU_DESC desc = gdbarch_tdep (target_gdbarch ())->cpu_desc;
+  mep_gdbarch_tdep *tdep
+    = (mep_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
+  CGEN_CPU_DESC desc = tdep->cpu_desc;
   const CGEN_HW_ENTRY *hw;
 
   if (me_module == CONFIG_NONE)
@@ -852,7 +854,11 @@ current_me_module (void)
       return (CONFIG_ATTR) regval;
     }
   else
-    return gdbarch_tdep (target_gdbarch ())->me_module;
+    {
+      mep_gdbarch_tdep *tdep
+	= (mep_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
+      return tdep->me_module;
+    }
 }
 
 
@@ -2326,7 +2332,6 @@ static struct gdbarch *
 mep_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* Which me_module are we building a gdbarch object for?  */
   CONFIG_ATTR me_module;
@@ -2384,10 +2389,15 @@ mep_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   for (arches = gdbarch_list_lookup_by_info (arches, &info); 
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
-    if (gdbarch_tdep (arches->gdbarch)->me_module == me_module)
-      return arches->gdbarch;
+    {
+      mep_gdbarch_tdep *tdep
+	= (mep_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
 
-  tdep = XCNEW (struct gdbarch_tdep);
+      if (tdep->me_module == me_module)
+	return arches->gdbarch;
+    }
+
+  mep_gdbarch_tdep *tdep = new mep_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Get a CGEN CPU descriptor for this architecture.  */
diff --git a/gdb/microblaze-tdep.c b/gdb/microblaze-tdep.c
index 0c3316d..5309da5 100644
--- a/gdb/microblaze-tdep.c
+++ b/gdb/microblaze-tdep.c
@@ -650,7 +650,6 @@ microblaze_register_g_packet_guesses (struct gdbarch *gdbarch)
 static struct gdbarch *
 microblaze_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -697,7 +696,7 @@ microblaze_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     }
 
   /* Allocate space for the new architecture.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  microblaze_gdbarch_tdep *tdep = new microblaze_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   set_gdbarch_long_double_bit (gdbarch, 128);
diff --git a/gdb/microblaze-tdep.h b/gdb/microblaze-tdep.h
index 08af0d1..3143e92 100644
--- a/gdb/microblaze-tdep.h
+++ b/gdb/microblaze-tdep.h
@@ -22,7 +22,7 @@
 
 
 /* Microblaze architecture-specific information.  */
-struct gdbarch_tdep
+struct microblaze_gdbarch_tdep : gdbarch_tdep
 {
 };
 
diff --git a/gdb/mips-linux-tdep.c b/gdb/mips-linux-tdep.c
index ce287f6..9eac3d7 100644
--- a/gdb/mips-linux-tdep.c
+++ b/gdb/mips-linux-tdep.c
@@ -1317,7 +1317,7 @@ mips_linux_get_syscall_number (struct gdbarch *gdbarch,
 			       thread_info *thread)
 {
   struct regcache *regcache = get_thread_regcache (thread);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int regsize = register_size (gdbarch, MIPS_V0_REGNUM);
   /* The content of a register */
@@ -1527,7 +1527,7 @@ static void
 mips_linux_init_abi (struct gdbarch_info info,
 		     struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum mips_abi abi = mips_abi (gdbarch);
   struct tdesc_arch_data *tdesc_data = info.tdesc_data;
 
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 89f689e..603c5d2 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -227,7 +227,8 @@ static const char mips_disassembler_options_n64[] = "gpr-names=64";
 const struct mips_regnum *
 mips_regnum (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->regnum;
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->regnum;
 }
 
 static int
@@ -248,29 +249,47 @@ mips_float_register_p (struct gdbarch *gdbarch, int regnum)
 	  && rawnum < mips_regnum (gdbarch)->fp0 + 32);
 }
 
-#define MIPS_EABI(gdbarch) (gdbarch_tdep (gdbarch)->mips_abi \
-		     == MIPS_ABI_EABI32 \
-		   || gdbarch_tdep (gdbarch)->mips_abi == MIPS_ABI_EABI64)
+static bool
+mips_eabi (gdbarch *arch)
+{
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (arch);
+  return (tdep->mips_abi == MIPS_ABI_EABI32 \
+	  || tdep->mips_abi == MIPS_ABI_EABI64);
+}
 
-#define MIPS_LAST_FP_ARG_REGNUM(gdbarch) \
-  (gdbarch_tdep (gdbarch)->mips_last_fp_arg_regnum)
+static int
+mips_last_fp_arg_regnum (gdbarch *arch)
+{
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->mips_last_fp_arg_regnum;
+}
 
-#define MIPS_LAST_ARG_REGNUM(gdbarch) \
-  (gdbarch_tdep (gdbarch)->mips_last_arg_regnum)
+static int
+mips_last_arg_regnum (gdbarch *arch)
+{
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->mips_last_arg_regnum;
+}
 
-#define MIPS_FPU_TYPE(gdbarch) (gdbarch_tdep (gdbarch)->mips_fpu_type)
+static enum mips_fpu_type
+mips_get_fpu_type (gdbarch *arch)
+{
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->mips_fpu_type;
+}
 
 /* Return the MIPS ABI associated with GDBARCH.  */
 enum mips_abi
 mips_abi (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->mips_abi;
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->mips_abi;
 }
 
 int
 mips_isa_regsize (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* If we know how big the registers are, use that size.  */
   if (tdep->register_size_valid_p)
@@ -316,7 +335,8 @@ mips_abi_regsize (struct gdbarch *gdbarch)
 static int
 is_mips16_isa (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->mips_isa == ISA_MIPS16;
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->mips_isa == ISA_MIPS16;
 }
 
 /* Return one iff compressed code is the microMIPS instruction set.  */
@@ -324,7 +344,8 @@ is_mips16_isa (struct gdbarch *gdbarch)
 static int
 is_micromips_isa (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->mips_isa == ISA_MICROMIPS;
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->mips_isa == ISA_MICROMIPS;
 }
 
 /* Return one iff ADDR denotes compressed code.  */
@@ -615,7 +636,7 @@ static const char * const mips_linux_reg_names[NUM_MIPS_PROCESSOR_REGS] = {
 static const char *
 mips_register_name (struct gdbarch *gdbarch, int regno)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   /* GPR names for all ABIs other than n32/n64.  */
   static const char *mips_gpr_names[] = {
     "zero", "at", "v0", "v1", "a0", "a1", "a2", "a3",
@@ -756,7 +777,9 @@ mips_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
   else if (register_size (gdbarch, rawnum) >
 	   register_size (gdbarch, cookednum))
     {
-      if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p)
+      mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+      if (tdep->mips64_transfers_32bit_regs_p)
 	return regcache->raw_read_part (rawnum, 0, 4, buf);
       else
 	{
@@ -787,7 +810,9 @@ mips_pseudo_register_write (struct gdbarch *gdbarch,
   else if (register_size (gdbarch, rawnum) >
 	   register_size (gdbarch, cookednum))
     {
-      if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p)
+      mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+      if (tdep->mips64_transfers_32bit_regs_p)
 	regcache->raw_write_part (rawnum, 0, 4, buf);
       else
 	{
@@ -829,7 +854,10 @@ mips_ax_pseudo_register_push_stack (struct gdbarch *gdbarch,
 
       if (register_size (gdbarch, rawnum) > register_size (gdbarch, reg))
 	{
-	  if (!gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p
+	  mips_gdbarch_tdep *tdep
+	    = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+	  if (!tdep->mips64_transfers_32bit_regs_p
 	      || gdbarch_byte_order (gdbarch) != BFD_ENDIAN_BIG)
 	    {
 	      ax_const_l (ax, 32);
@@ -1031,6 +1059,7 @@ mips_register_type (struct gdbarch *gdbarch, int regnum)
   else
     {
       int rawnum = regnum - gdbarch_num_regs (gdbarch);
+      mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
       /* The cooked or ABI registers.  These are sized according to
 	 the ABI (with a few complications).  */
@@ -1043,7 +1072,7 @@ mips_register_type (struct gdbarch *gdbarch, int regnum)
 	/* The pseudo/cooked view of the embedded registers is always
 	   32-bit.  The raw view is handled below.  */
 	return builtin_type (gdbarch)->builtin_int32;
-      else if (gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p)
+      else if (tdep->mips64_transfers_32bit_regs_p)
 	/* The target, while possibly using a 64-bit register buffer,
 	   is only transfering 32-bits of each integer register.
 	   Reflect this in the cooked/pseudo (ABI) register value.  */
@@ -1132,7 +1161,7 @@ mips_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
 static enum auto_boolean mask_address_var = AUTO_BOOLEAN_AUTO;
 
 static int
-mips_mask_address_p (struct gdbarch_tdep *tdep)
+mips_mask_address_p (mips_gdbarch_tdep *tdep)
 {
   switch (mask_address_var)
     {
@@ -1154,7 +1183,8 @@ static void
 show_mask_address (struct ui_file *file, int from_tty,
 		   struct cmd_list_element *c, const char *value)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (target_gdbarch ());
+  mips_gdbarch_tdep *tdep
+    = (mips_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
 
   deprecated_show_value_hack (file, from_tty, c, value);
   switch (mask_address_var)
@@ -1698,9 +1728,9 @@ mips32_next_pc (struct regcache *regcache, CORE_ADDR pc)
 	      break;
 	    case 12:            /* SYSCALL */
 	      {
-		struct gdbarch_tdep *tdep;
+		mips_gdbarch_tdep *tdep
+		  = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
-		tdep = gdbarch_tdep (gdbarch);
 		if (tdep->syscall_next_pc != NULL)
 		  pc = tdep->syscall_next_pc (get_current_frame ());
 		else
@@ -1909,9 +1939,9 @@ micromips_next_pc (struct regcache *regcache, CORE_ADDR pc)
 		  break;
 		case 0x22d: /* SYSCALL:  000000 1000101101 111100 */
 		  {
-		    struct gdbarch_tdep *tdep;
+		    mips_gdbarch_tdep *tdep
+		      = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
-		    tdep = gdbarch_tdep (gdbarch);
 		    if (tdep->syscall_next_pc != NULL)
 		      pc = tdep->syscall_next_pc (get_current_frame ());
 		  }
@@ -3870,7 +3900,7 @@ mips_stub_frame_base_sniffer (struct frame_info *this_frame)
 static CORE_ADDR
 mips_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (mips_mask_address_p (tdep) && (((ULONGEST) addr) >> 32 == 0xffffffffUL))
     /* This hack is a work-around for existing boards using PMON, the
@@ -4405,13 +4435,13 @@ fp_register_arg_p (struct gdbarch *gdbarch, enum type_code typecode,
 		   struct type *arg_type)
 {
   return ((typecode == TYPE_CODE_FLT
-	   || (MIPS_EABI (gdbarch)
+	   || (mips_eabi (gdbarch)
 	       && (typecode == TYPE_CODE_STRUCT
 		   || typecode == TYPE_CODE_UNION)
 	       && arg_type->num_fields () == 1
 	       && check_typedef (arg_type->field (0).type ())->code ()
 	       == TYPE_CODE_FLT))
-	  && MIPS_FPU_TYPE(gdbarch) != MIPS_FPU_NONE);
+	  && mips_get_fpu_type (gdbarch) != MIPS_FPU_NONE);
 }
 
 /* On o32, argument passing in GPRs depends on the alignment of the type being
@@ -4611,7 +4641,7 @@ mips_eabi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	 point value into an FP register instead of pushing it onto the
 	 stack.  */
       if (fp_register_arg_p (gdbarch, typecode, arg_type)
-	  && float_argreg <= MIPS_LAST_FP_ARG_REGNUM (gdbarch))
+	  && float_argreg <= mips_last_fp_arg_regnum (gdbarch))
 	{
 	  /* EABI32 will pass doubles in consecutive registers, even on
 	     64-bit cores.  At one time, we used to check the size of
@@ -4678,7 +4708,7 @@ mips_eabi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 				    partial_len);
 
 	      /* Write this portion of the argument to the stack.  */
-	      if (argreg > MIPS_LAST_ARG_REGNUM (gdbarch)
+	      if (argreg > mips_last_arg_regnum (gdbarch)
 		  || odd_sized_struct
 		  || fp_register_arg_p (gdbarch, typecode, arg_type))
 		{
@@ -4729,7 +4759,7 @@ mips_eabi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		 arguments will not.  */
 	      /* Write this portion of the argument to a general
 		 purpose register.  */
-	      if (argreg <= MIPS_LAST_ARG_REGNUM (gdbarch)
+	      if (argreg <= mips_last_arg_regnum (gdbarch)
 		  && !fp_register_arg_p (gdbarch, typecode, arg_type))
 		{
 		  LONGEST regval =
@@ -4773,7 +4803,7 @@ mips_eabi_return_value (struct gdbarch *gdbarch, struct value *function,
 			struct type *type, struct regcache *regcache,
 			gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int fp_return_type = 0;
   int offset, regnum, xfer;
 
@@ -4845,7 +4875,7 @@ mips_n32n64_fp_arg_chunk_p (struct gdbarch *gdbarch, struct type *arg_type,
   if (arg_type->code () != TYPE_CODE_STRUCT)
     return 0;
 
-  if (MIPS_FPU_TYPE (gdbarch) != MIPS_FPU_DOUBLE)
+  if (mips_get_fpu_type (gdbarch) != MIPS_FPU_DOUBLE)
     return 0;
 
   if (TYPE_LENGTH (arg_type) < offset + MIPS64_REGSIZE)
@@ -4973,7 +5003,7 @@ mips_n32n64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	}
 
       if (fp_register_arg_p (gdbarch, typecode, arg_type)
-	  && argreg <= MIPS_LAST_ARG_REGNUM (gdbarch))
+	  && argreg <= mips_last_arg_regnum (gdbarch))
 	{
 	  /* This is a floating point value that fits entirely
 	     in a single register or a pair of registers.  */
@@ -5033,10 +5063,10 @@ mips_n32n64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 				    partial_len);
 
 	      if (fp_register_arg_p (gdbarch, typecode, arg_type))
-		gdb_assert (argreg > MIPS_LAST_ARG_REGNUM (gdbarch));
+		gdb_assert (argreg > mips_last_arg_regnum (gdbarch));
 
 	      /* Write this portion of the argument to the stack.  */
-	      if (argreg > MIPS_LAST_ARG_REGNUM (gdbarch))
+	      if (argreg > mips_last_arg_regnum (gdbarch))
 		{
 		  /* Should shorter than int integer values be
 		     promoted to int before being stored?  */
@@ -5079,7 +5109,7 @@ mips_n32n64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		 structs may go thru BOTH paths.  */
 	      /* Write this portion of the argument to a general
 		 purpose register.  */
-	      if (argreg <= MIPS_LAST_ARG_REGNUM (gdbarch))
+	      if (argreg <= mips_last_arg_regnum (gdbarch))
 		{
 		  LONGEST regval;
 
@@ -5164,7 +5194,7 @@ mips_n32n64_return_value (struct gdbarch *gdbarch, struct value *function,
 			  struct type *type, struct regcache *regcache,
 			  gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* From MIPSpro N32 ABI Handbook, Document Number: 007-2816-004
 
@@ -5451,7 +5481,7 @@ mips_o32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	 registers are normally skipped.  */
 
       if (fp_register_arg_p (gdbarch, typecode, arg_type)
-	  && float_argreg <= MIPS_LAST_FP_ARG_REGNUM (gdbarch))
+	  && float_argreg <= mips_last_fp_arg_regnum (gdbarch))
 	{
 	  if (register_size (gdbarch, float_argreg) < 8 && len == 8)
 	    {
@@ -5541,7 +5571,7 @@ mips_o32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 				    partial_len);
 
 	      /* Write this portion of the argument to the stack.  */
-	      if (argreg > MIPS_LAST_ARG_REGNUM (gdbarch)
+	      if (argreg > mips_last_arg_regnum (gdbarch)
 		  || odd_sized_struct)
 		{
 		  /* Should shorter than int integer values be
@@ -5577,7 +5607,7 @@ mips_o32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		 structs may go thru BOTH paths.  */
 	      /* Write this portion of the argument to a general
 		 purpose register.  */
-	      if (argreg <= MIPS_LAST_ARG_REGNUM (gdbarch))
+	      if (argreg <= mips_last_arg_regnum (gdbarch))
 		{
 		  LONGEST regval = extract_signed_integer (val, partial_len,
 							   byte_order);
@@ -5625,7 +5655,7 @@ mips_o32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 
 		  /* Prevent subsequent floating point arguments from
 		     being passed in floating point registers.  */
-		  float_argreg = MIPS_LAST_FP_ARG_REGNUM (gdbarch) + 1;
+		  float_argreg = mips_last_fp_arg_regnum (gdbarch) + 1;
 		}
 
 	      len -= partial_len;
@@ -5659,7 +5689,7 @@ mips_o32_return_value (struct gdbarch *gdbarch, struct value *function,
 {
   CORE_ADDR func_addr = function ? find_function_addr (function, NULL) : 0;
   int mips16 = mips_pc_is_mips16 (gdbarch, func_addr);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum mips_fval_reg fval_reg;
 
   fval_reg = readbuf ? mips16 ? mips_fval_gpr : mips_fval_fpr : mips_fval_both;
@@ -5960,7 +5990,7 @@ mips_o64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	 functions because those registers are normally skipped.  */
 
       if (fp_register_arg_p (gdbarch, typecode, arg_type)
-	  && float_argreg <= MIPS_LAST_FP_ARG_REGNUM (gdbarch))
+	  && float_argreg <= mips_last_fp_arg_regnum (gdbarch))
 	{
 	  LONGEST regval = extract_unsigned_integer (val, len, byte_order);
 	  if (mips_debug)
@@ -5995,7 +6025,7 @@ mips_o64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 				    partial_len);
 
 	      /* Write this portion of the argument to the stack.  */
-	      if (argreg > MIPS_LAST_ARG_REGNUM (gdbarch)
+	      if (argreg > mips_last_arg_regnum (gdbarch)
 		  || odd_sized_struct)
 		{
 		  /* Should shorter than int integer values be
@@ -6039,7 +6069,7 @@ mips_o64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		 structs may go thru BOTH paths.  */
 	      /* Write this portion of the argument to a general
 		 purpose register.  */
-	      if (argreg <= MIPS_LAST_ARG_REGNUM (gdbarch))
+	      if (argreg <= mips_last_arg_regnum (gdbarch))
 		{
 		  LONGEST regval = extract_signed_integer (val, partial_len,
 							   byte_order);
@@ -6071,7 +6101,7 @@ mips_o64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 
 		  /* Prevent subsequent floating point arguments from
 		     being passed in floating point registers.  */
-		  float_argreg = MIPS_LAST_FP_ARG_REGNUM (gdbarch) + 1;
+		  float_argreg = mips_last_fp_arg_regnum (gdbarch) + 1;
 		}
 
 	      len -= partial_len;
@@ -6403,7 +6433,7 @@ mips_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
 		      struct frame_info *frame, const char *args)
 {
   int fcsr = mips_regnum (gdbarch)->fp_control_status;
-  enum mips_fpu_type type = MIPS_FPU_TYPE (gdbarch);
+  enum mips_fpu_type type = mips_get_fpu_type (gdbarch);
   ULONGEST fcs = 0;
   int i;
 
@@ -6891,7 +6921,7 @@ show_mipsfpu_command (const char *args, int from_tty)
       return;
     }
 
-  switch (MIPS_FPU_TYPE (target_gdbarch ()))
+  switch (mips_get_fpu_type (target_gdbarch ()))
     {
     case MIPS_FPU_SINGLE:
       fpu = "single-precision";
@@ -8038,7 +8068,6 @@ static struct gdbarch *
 mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int elf_flags;
   enum mips_abi mips_abi, found_abi, wanted_abi;
   int i, num_regs;
@@ -8055,7 +8084,11 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   if (info.abfd && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour)
     elf_flags = elf_elfheader (info.abfd)->e_flags;
   else if (arches != NULL)
-    elf_flags = gdbarch_tdep (arches->gdbarch)->elf_flags;
+    {
+      mips_gdbarch_tdep *tdep
+	= (mips_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+      elf_flags = tdep->elf_flags;
+    }
   else
     elf_flags = 0;
   if (gdbarch_debug)
@@ -8092,7 +8125,11 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* If we have no useful BFD information, use the ABI from the last
      MIPS architecture (if there is one).  */
   if (found_abi == MIPS_ABI_UNKNOWN && info.abfd == NULL && arches != NULL)
-    found_abi = gdbarch_tdep (arches->gdbarch)->found_abi;
+    {
+      mips_gdbarch_tdep *tdep
+	= (mips_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+      found_abi = tdep->found_abi;
+    }
 
   /* Try the architecture for any hint of the correct ABI.  */
   if (found_abi == MIPS_ABI_UNKNOWN
@@ -8223,7 +8260,7 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 	break;
       }
   else if (arches != NULL)
-    fpu_type = MIPS_FPU_TYPE (arches->gdbarch);
+    fpu_type = mips_get_fpu_type (arches->gdbarch);
   else
     fpu_type = MIPS_FPU_DOUBLE;
   if (gdbarch_debug)
@@ -8406,28 +8443,31 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
+      mips_gdbarch_tdep *tdep
+        = (mips_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
       /* MIPS needs to be pedantic about which ABI and the compressed
 	 ISA variation the object is using.  */
-      if (gdbarch_tdep (arches->gdbarch)->elf_flags != elf_flags)
+      if (tdep->elf_flags != elf_flags)
 	continue;
-      if (gdbarch_tdep (arches->gdbarch)->mips_abi != mips_abi)
+      if (tdep->mips_abi != mips_abi)
 	continue;
-      if (gdbarch_tdep (arches->gdbarch)->mips_isa != mips_isa)
+      if (tdep->mips_isa != mips_isa)
 	continue;
       /* Need to be pedantic about which register virtual size is
 	 used.  */
-      if (gdbarch_tdep (arches->gdbarch)->mips64_transfers_32bit_regs_p
+      if (tdep->mips64_transfers_32bit_regs_p
 	  != mips64_transfers_32bit_regs_p)
 	continue;
       /* Be pedantic about which FPU is selected.  */
-      if (MIPS_FPU_TYPE (arches->gdbarch) != fpu_type)
+      if (mips_get_fpu_type (arches->gdbarch) != fpu_type)
 	continue;
 
       return arches->gdbarch;
     }
 
   /* Need a new architecture.  Fill in a target specific vector.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  mips_gdbarch_tdep *tdep = new mips_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->elf_flags = elf_flags;
   tdep->mips64_transfers_32bit_regs_p = mips64_transfers_32bit_regs_p;
@@ -8862,7 +8902,7 @@ mips_fpu_type_str (enum mips_fpu_type fpu_type)
 static void
 mips_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mips_gdbarch_tdep *tdep = (mips_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep != NULL)
     {
       int ef_mips_arch;
@@ -8911,11 +8951,11 @@ mips_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 		      MIPS_DEFAULT_FPU_TYPE,
 		      mips_fpu_type_str (MIPS_DEFAULT_FPU_TYPE));
   fprintf_unfiltered (file, "mips_dump_tdep: MIPS_EABI = %d\n",
-		      MIPS_EABI (gdbarch));
+		      mips_eabi (gdbarch));
   fprintf_unfiltered (file,
 		      "mips_dump_tdep: MIPS_FPU_TYPE = %d (%s)\n",
-		      MIPS_FPU_TYPE (gdbarch),
-		      mips_fpu_type_str (MIPS_FPU_TYPE (gdbarch)));
+		      mips_get_fpu_type (gdbarch),
+		      mips_fpu_type_str (mips_get_fpu_type (gdbarch)));
 }
 
 void _initialize_mips_tdep ();
diff --git a/gdb/mips-tdep.h b/gdb/mips-tdep.h
index e7f6837..b899cfd 100644
--- a/gdb/mips-tdep.h
+++ b/gdb/mips-tdep.h
@@ -83,39 +83,39 @@ enum mips_fpu_type
 };
 
 /* MIPS specific per-architecture information.  */
-struct gdbarch_tdep
+struct mips_gdbarch_tdep : gdbarch_tdep
 {
   /* from the elf header */
-  int elf_flags;
+  int elf_flags = 0;
 
   /* mips options */
-  enum mips_abi mips_abi;
-  enum mips_abi found_abi;
-  enum mips_isa mips_isa;
-  enum mips_fpu_type mips_fpu_type;
-  int mips_last_arg_regnum;
-  int mips_last_fp_arg_regnum;
-  int default_mask_address_p;
+  enum mips_abi mips_abi {};
+  enum mips_abi found_abi {};
+  enum mips_isa mips_isa {};
+  enum mips_fpu_type mips_fpu_type {};
+  int mips_last_arg_regnum = 0;
+  int mips_last_fp_arg_regnum = 0;
+  int default_mask_address_p = 0;
   /* Is the target using 64-bit raw integer registers but only
      storing a left-aligned 32-bit value in each?  */
-  int mips64_transfers_32bit_regs_p;
+  int mips64_transfers_32bit_regs_p = 0;
   /* Indexes for various registers.  IRIX and embedded have
      different values.  This contains the "public" fields.  Don't
      add any that do not need to be public.  */
-  const struct mips_regnum *regnum;
+  const struct mips_regnum *regnum = nullptr;
   /* Register names table for the current register set.  */
-  const char * const *mips_processor_reg_names;
+  const char * const *mips_processor_reg_names = nullptr;
 
   /* The size of register data available from the target, if known.
      This doesn't quite obsolete the manual
      mips64_transfers_32bit_regs_p, since that is documented to force
      left alignment even for big endian (very strange).  */
-  int register_size_valid_p;
-  int register_size;
+  int register_size_valid_p = 0;
+  int register_size = 0;
 
   /* Return the expected next PC if FRAME is stopped at a syscall
      instruction.  */
-  CORE_ADDR (*syscall_next_pc) (struct frame_info *frame);
+  CORE_ADDR (*syscall_next_pc) (struct frame_info *frame) = nullptr;
 };
 
 /* Register numbers of various important registers.  */
diff --git a/gdb/mn10300-tdep.c b/gdb/mn10300-tdep.c
index 7feab0b..5804efe 100644
--- a/gdb/mn10300-tdep.c
+++ b/gdb/mn10300-tdep.c
@@ -372,7 +372,7 @@ mn10300_analyze_prologue (struct gdbarch *gdbarch,
   int rn;
   pv_t regs[MN10300_MAX_NUM_REGS];
   CORE_ADDR after_last_frame_setup_insn = start_pc;
-  int am33_mode = AM33_MODE (gdbarch);
+  int am33_mode = get_am33_mode (gdbarch);
 
   memset (result, 0, sizeof (*result));
   result->gdbarch = gdbarch;
@@ -1337,14 +1337,13 @@ mn10300_gdbarch_init (struct gdbarch_info info,
 		      struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int num_regs;
 
   arches = gdbarch_list_lookup_by_info (arches, &info);
   if (arches != NULL)
     return arches->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  mn10300_gdbarch_tdep *tdep = new mn10300_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   switch (info.bfd_arch_info->mach)
@@ -1413,7 +1412,7 @@ mn10300_gdbarch_init (struct gdbarch_info info,
 static void
 mn10300_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  mn10300_gdbarch_tdep *tdep = (mn10300_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   fprintf_unfiltered (file, "mn10300_dump_tdep: am33_mode = %d\n",
 		      tdep->am33_mode);
 }
diff --git a/gdb/mn10300-tdep.h b/gdb/mn10300-tdep.h
index a351849..220e4d6 100644
--- a/gdb/mn10300-tdep.h
+++ b/gdb/mn10300-tdep.h
@@ -20,6 +20,8 @@
 #ifndef MN10300_TDEP_H
 #define MN10300_TDEP_H
 
+#include "gdbarch.h"
+
 enum {
   E_D0_REGNUM = 0,
   E_D1_REGNUM = 1,
@@ -74,11 +76,16 @@ enum frame_kind {
 };
 
 /* mn10300 private data.  */
-struct gdbarch_tdep
+struct mn10300_gdbarch_tdep : gdbarch_tdep
 {
   int am33_mode;
 };
 
-#define AM33_MODE(gdbarch) (gdbarch_tdep (gdbarch)->am33_mode)
+static inline int
+get_am33_mode (gdbarch *arch)
+{
+  mn10300_gdbarch_tdep *tdep = (mn10300_gdbarch_tdep *) gdbarch_tdep (arch);
+  return tdep->am33_mode;
+}
 
 #endif /* MN10300_TDEP_H */
diff --git a/gdb/moxie-tdep.c b/gdb/moxie-tdep.c
index c48f9f7..459bfb8 100644
--- a/gdb/moxie-tdep.c
+++ b/gdb/moxie-tdep.c
@@ -1052,7 +1052,6 @@ static struct gdbarch *
 moxie_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* If there is already a candidate, use it.  */
   arches = gdbarch_list_lookup_by_info (arches, &info);
@@ -1060,7 +1059,7 @@ moxie_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Allocate space for the new architecture.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  moxie_gdbarch_tdep *tdep = new moxie_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   set_gdbarch_wchar_bit (gdbarch, 32);
diff --git a/gdb/moxie-tdep.h b/gdb/moxie-tdep.h
index b3687ef..4e6bcd1 100644
--- a/gdb/moxie-tdep.h
+++ b/gdb/moxie-tdep.h
@@ -20,7 +20,7 @@
 #ifndef MOXIE_TDEP_H
 #define MOXIE_TDEP_H
 
-struct gdbarch_tdep
+struct moxie_gdbarch_tdep : gdbarch_tdep
 {
   /* gdbarch target dependent data here.  Currently unused for MOXIE.  */
 };
diff --git a/gdb/msp430-tdep.c b/gdb/msp430-tdep.c
index c1b0c4c..f3c44b7 100644
--- a/gdb/msp430-tdep.c
+++ b/gdb/msp430-tdep.c
@@ -104,19 +104,19 @@ enum
 
 /* Architecture specific data.  */
 
-struct gdbarch_tdep
+struct msp430_gdbarch_tdep : gdbarch_tdep
 {
   /* The ELF header flags specify the multilib used.  */
-  int elf_flags;
+  int elf_flags = 0;
 
   /* One of MSP_ISA_MSP430 or MSP_ISA_MSP430X.  */
-  int isa;
+  int isa = 0;
 
   /* One of MSP_SMALL_CODE_MODEL or MSP_LARGE_CODE_MODEL.  If, at
      some point, we support different data models too, we'll probably
      structure things so that we can combine values using logical
      "or".  */
-  int code_model;
+  int code_model = 0;
 };
 
 /* This structure holds the results of a prologue analysis.  */
@@ -340,7 +340,8 @@ msp430_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc,
   int rn;
   pv_t reg[MSP430_NUM_TOTAL_REGS];
   CORE_ADDR after_last_frame_setup_insn = start_pc;
-  int code_model = gdbarch_tdep (gdbarch)->code_model;
+  msp430_gdbarch_tdep *tdep = (msp430_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int code_model = tdep->code_model;
   int sz;
 
   memset (result, 0, sizeof (*result));
@@ -568,7 +569,8 @@ msp430_return_value (struct gdbarch *gdbarch,
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   LONGEST valtype_len = TYPE_LENGTH (valtype);
-  int code_model = gdbarch_tdep (gdbarch)->code_model;
+  msp430_gdbarch_tdep *tdep = (msp430_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int code_model = tdep->code_model;
 
   if (TYPE_LENGTH (valtype) > 8
       || valtype->code () == TYPE_CODE_STRUCT
@@ -648,7 +650,8 @@ msp430_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int write_pass;
   int sp_off = 0;
   CORE_ADDR cfa;
-  int code_model = gdbarch_tdep (gdbarch)->code_model;
+  msp430_gdbarch_tdep *tdep = (msp430_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int code_model = tdep->code_model;
 
   struct type *func_type = value_type (function);
 
@@ -766,8 +769,7 @@ msp430_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 
   /* Push the return address.  */
   {
-    int sz = (gdbarch_tdep (gdbarch)->code_model == MSP_SMALL_CODE_MODEL)
-      ? 2 : 4;
+    int sz = tdep->code_model == MSP_SMALL_CODE_MODEL ? 2 : 4;
     sp = sp - sz;
     write_memory_unsigned_integer (sp, sz, byte_order, bp_addr);
   }
@@ -811,7 +813,8 @@ msp430_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 
   stub_name = bms.minsym->linkage_name ();
 
-  if (gdbarch_tdep (gdbarch)->code_model == MSP_SMALL_CODE_MODEL
+  msp430_gdbarch_tdep *tdep = (msp430_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->code_model == MSP_SMALL_CODE_MODEL
       && msp430_in_return_stub (gdbarch, pc, stub_name))
     {
       CORE_ADDR sp = get_frame_register_unsigned (frame, MSP430_SP_REGNUM);
@@ -830,7 +833,6 @@ static struct gdbarch *
 msp430_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int elf_flags, isa, code_model;
 
   /* Extract the elf_flags if available.  */
@@ -873,7 +875,8 @@ msp430_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 	  struct gdbarch *ca = get_current_arch ();
 	  if (ca && gdbarch_bfd_arch_info (ca)->arch == bfd_arch_msp430)
 	    {
-	      struct gdbarch_tdep *ca_tdep = gdbarch_tdep (ca);
+	      msp430_gdbarch_tdep *ca_tdep
+		= (msp430_gdbarch_tdep *) gdbarch_tdep (ca);
 
 	      elf_flags = ca_tdep->elf_flags;
 	      isa = ca_tdep->isa;
@@ -899,7 +902,8 @@ msp430_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      struct gdbarch_tdep *candidate_tdep = gdbarch_tdep (arches->gdbarch);
+      msp430_gdbarch_tdep *candidate_tdep
+	= (msp430_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
 
       if (candidate_tdep->elf_flags != elf_flags
 	  || candidate_tdep->isa != isa
@@ -911,7 +915,7 @@ msp430_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* None found, create a new architecture from the information
      provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  msp430_gdbarch_tdep *tdep = new msp430_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->elf_flags = elf_flags;
   tdep->isa = isa;
diff --git a/gdb/nds32-tdep.c b/gdb/nds32-tdep.c
index 828853e..0360323 100644
--- a/gdb/nds32-tdep.c
+++ b/gdb/nds32-tdep.c
@@ -289,7 +289,7 @@ typedef BP_MANIPULATION (nds32_break_insn) nds32_breakpoint;
 static int
 nds32_dwarf2_reg_to_regnum (struct gdbarch *gdbarch, int num)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const int FSR = 38;
   const int FDR = FSR + 32;
 
@@ -440,7 +440,7 @@ nds32_pseudo_register_read (struct gdbarch *gdbarch,
 			    readable_regcache *regcache, int regnum,
 			    gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_byte reg_buf[8];
   int offset, fdr_regnum;
   enum register_status status;
@@ -479,7 +479,7 @@ nds32_pseudo_register_write (struct gdbarch *gdbarch,
 			     struct regcache *regcache, int regnum,
 			     const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_byte reg_buf[8];
   int offset, fdr_regnum;
 
@@ -616,7 +616,7 @@ static CORE_ADDR
 nds32_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR pc,
 			CORE_ADDR limit_pc, struct nds32_frame_cache *cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int abi_use_fpr = nds32_abi_use_fpr (tdep->elf_abi);
   /* Current scanning status.  */
   int in_prologue_bb = 0;
@@ -1177,7 +1177,7 @@ static int
 nds32_analyze_epilogue (struct gdbarch *gdbarch, CORE_ADDR pc,
 			struct nds32_frame_cache *cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int abi_use_fpr = nds32_abi_use_fpr (tdep->elf_abi);
   CORE_ADDR limit_pc;
   uint32_t insn, insn_len;
@@ -1228,7 +1228,7 @@ nds32_analyze_epilogue (struct gdbarch *gdbarch, CORE_ADDR pc,
 static int
 nds32_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int abi_use_fpr = nds32_abi_use_fpr (tdep->elf_abi);
   int insn_type = INSN_NORMAL;
   int ret_found = 0;
@@ -1432,7 +1432,7 @@ nds32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int i;
   ULONGEST regval;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct type *func_type = value_type (function);
   int abi_use_fpr = nds32_abi_use_fpr (tdep->elf_abi);
   int abi_split = nds32_abi_split (tdep->elf_abi);
@@ -1660,7 +1660,7 @@ nds32_extract_return_value (struct gdbarch *gdbarch, struct type *type,
 			    struct regcache *regcache, gdb_byte *valbuf)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int abi_use_fpr = nds32_abi_use_fpr (tdep->elf_abi);
   int calling_use_fpr;
   int len;
@@ -1750,7 +1750,7 @@ nds32_store_return_value (struct gdbarch *gdbarch, struct type *type,
 			  struct regcache *regcache, const gdb_byte *valbuf)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nds32_gdbarch_tdep *tdep = (nds32_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int abi_use_fpr = nds32_abi_use_fpr (tdep->elf_abi);
   int calling_use_fpr;
   int len;
@@ -1955,7 +1955,6 @@ static struct gdbarch *
 nds32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   struct gdbarch_list *best_arch;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -1973,7 +1972,8 @@ nds32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch != NULL;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
-      struct gdbarch_tdep *idep = gdbarch_tdep (best_arch->gdbarch);
+      nds32_gdbarch_tdep *idep
+	= (nds32_gdbarch_tdep *) gdbarch_tdep (best_arch->gdbarch);
 
       if (idep->elf_abi != elf_abi)
 	continue;
@@ -1995,7 +1995,7 @@ nds32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return NULL;
 
   /* Allocate space for the new architecture.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  nds32_gdbarch_tdep *tdep = new nds32_gdbarch_tdep;
   tdep->fpu_freg = fpu_freg;
   tdep->use_pseudo_fsrs = use_pseudo_fsrs;
   tdep->fs0_regnum = -1;
diff --git a/gdb/nds32-tdep.h b/gdb/nds32-tdep.h
index 2422930..e065123 100644
--- a/gdb/nds32-tdep.h
+++ b/gdb/nds32-tdep.h
@@ -40,15 +40,15 @@ enum nds32_regnum
   NDS32_FD0_REGNUM = NDS32_NUM_REGS,
 };
 
-struct gdbarch_tdep
+struct nds32_gdbarch_tdep : gdbarch_tdep
 {
   /* The guessed FPU configuration.  */
-  int fpu_freg;
+  int fpu_freg = 0;
   /* FSRs are defined as pseudo registers.  */
-  int use_pseudo_fsrs;
+  int use_pseudo_fsrs = 0;
   /* Cached regnum of the first FSR (FS0).  */
-  int fs0_regnum;
+  int fs0_regnum = 0;
   /* ELF ABI info.  */
-  int elf_abi;
+  int elf_abi = 0;
 };
 #endif /* NDS32_TDEP_H */
diff --git a/gdb/nios2-linux-tdep.c b/gdb/nios2-linux-tdep.c
index bd86146..2e360ba 100644
--- a/gdb/nios2-linux-tdep.c
+++ b/gdb/nios2-linux-tdep.c
@@ -217,7 +217,7 @@ nios2_linux_is_kernel_helper (CORE_ADDR pc)
 static void
 nios2_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nios2_gdbarch_tdep *tdep = (nios2_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/nios2-tdep.c b/gdb/nios2-tdep.c
index be5544e..706b579 100644
--- a/gdb/nios2-tdep.c
+++ b/gdb/nios2-tdep.c
@@ -2098,7 +2098,7 @@ static CORE_ADDR
 nios2_get_next_pc (struct regcache *regcache, CORE_ADDR pc)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nios2_gdbarch_tdep *tdep = (nios2_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach;
   unsigned int insn;
   const struct nios2_opcode *op = nios2_fetch_insn (gdbarch, pc, &insn);
@@ -2221,7 +2221,7 @@ static int
 nios2_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nios2_gdbarch_tdep *tdep = (nios2_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR jb_addr = get_frame_register_unsigned (frame, NIOS2_R4_REGNUM);
   gdb_byte buf[4];
@@ -2275,7 +2275,6 @@ static struct gdbarch *
 nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int i;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -2313,7 +2312,7 @@ nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* None found, create a new architecture from the information
      provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  nios2_gdbarch_tdep *tdep = new nios2_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* longjmp support not enabled by default.  */
diff --git a/gdb/nios2-tdep.h b/gdb/nios2-tdep.h
index f9e7349..96f1865 100644
--- a/gdb/nios2-tdep.h
+++ b/gdb/nios2-tdep.h
@@ -20,6 +20,8 @@
 #ifndef NIOS2_TDEP_H
 #define NIOS2_TDEP_H
 
+#include "gdbarch.h"
+
 /* Nios II ISA specific encodings and macros.  */
 #include "opcode/nios2.h"
 
@@ -67,19 +69,19 @@
 #define NIOS2_CDX_OPCODE_SIZE 2
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct nios2_gdbarch_tdep : gdbarch_tdep
 {
   /* Assumes FRAME is stopped at a syscall (trap) instruction; returns
      the expected next PC.  */
   CORE_ADDR (*syscall_next_pc) (struct frame_info *frame,
-				const struct nios2_opcode *op);
+				const struct nios2_opcode *op) = nullptr;
 
   /* Returns true if PC points to a kernel helper function.  */
-  bool (*is_kernel_helper) (CORE_ADDR pc);
+  bool (*is_kernel_helper) (CORE_ADDR pc) = nullptr;
 
   /* Offset to PC value in jump buffer.
      If this is negative, longjmp support will be disabled.  */
-  int jb_pc;
+  int jb_pc = 0;
 };
 
 extern struct target_desc *tdesc_nios2_linux;
diff --git a/gdb/or1k-tdep.c b/gdb/or1k-tdep.c
index 4c42e02..346ee97 100644
--- a/gdb/or1k-tdep.c
+++ b/gdb/or1k-tdep.c
@@ -62,11 +62,11 @@ show_or1k_debug (struct ui_file *file, int from_tty,
 
 /* The target-dependent structure for gdbarch.  */
 
-struct gdbarch_tdep
+struct or1k_gdbarch_tdep : gdbarch_tdep
 {
-  int bytes_per_word;
-  int bytes_per_address;
-  CGEN_CPU_DESC gdb_cgen_cpu_desc;
+  int bytes_per_word = 0;
+  int bytes_per_address = 0;
+  CGEN_CPU_DESC gdb_cgen_cpu_desc = nullptr;
 };
 
 /* Support functions for the architecture definition.  */
@@ -247,7 +247,8 @@ or1k_return_value (struct gdbarch *gdbarch, struct value *functype,
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   enum type_code rv_type = valtype->code ();
   unsigned int rv_size = TYPE_LENGTH (valtype);
-  int bpw = (gdbarch_tdep (gdbarch))->bytes_per_word;
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int bpw = tdep->bytes_per_word;
 
   /* Deal with struct/union as addresses.  If an array won't fit in a
      single register it is returned as address.  Anything larger than 2
@@ -351,7 +352,7 @@ or1k_delay_slot_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
   const CGEN_INSN *insn;
   CGEN_FIELDS tmp_fields;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   insn = cgen_lookup_insn (tdep->gdb_cgen_cpu_desc,
 			   NULL,
@@ -633,8 +634,9 @@ or1k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int heap_offset = 0;
   CORE_ADDR heap_sp = sp - 128;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  int bpa = (gdbarch_tdep (gdbarch))->bytes_per_address;
-  int bpw = (gdbarch_tdep (gdbarch))->bytes_per_word;
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int bpa = tdep->bytes_per_address;
+  int bpw = tdep->bytes_per_word;
   struct type *func_type = value_type (function);
 
   /* Return address */
@@ -1140,7 +1142,6 @@ static struct gdbarch *
 or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   const struct bfd_arch_info *binfo;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -1155,7 +1156,7 @@ or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
      actually know which target we are talking to, but put in some defaults
      for now.  */
   binfo = info.bfd_arch_info;
-  tdep = XCNEW (struct gdbarch_tdep);
+  or1k_gdbarch_tdep *tdep = new or1k_gdbarch_tdep;
   tdep->bytes_per_word = binfo->bits_per_word / binfo->bits_per_byte;
   tdep->bytes_per_address = binfo->bits_per_address / binfo->bits_per_byte;
   gdbarch = gdbarch_alloc (&info, tdep);
@@ -1283,7 +1284,7 @@ or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 or1k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (NULL == tdep)
     return; /* Nothing to report */
diff --git a/gdb/ppc-fbsd-tdep.c b/gdb/ppc-fbsd-tdep.c
index f41c8bb..87d2a69 100644
--- a/gdb/ppc-fbsd-tdep.c
+++ b/gdb/ppc-fbsd-tdep.c
@@ -126,7 +126,7 @@ ppcfbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				      void *cb_data,
 				      const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->wordsize == 4)
     cb (".reg", 148, 148, &ppc32_fbsd_gregset, NULL, cb_data);
@@ -200,7 +200,7 @@ static struct trad_frame_cache *
 ppcfbsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct trad_frame_cache *cache;
   CORE_ADDR addr, base, func;
   gdb_byte buf[PPC_INSN_SIZE];
@@ -287,7 +287,7 @@ static CORE_ADDR
 ppcfbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 				  CORE_ADDR lm_addr, CORE_ADDR offset)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct regcache *regcache;
   int tp_offset, tp_regnum;
 
@@ -319,7 +319,7 @@ ppcfbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
 static void
 ppcfbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Generic FreeBSD support. */
   fbsd_init_abi (info, gdbarch);
diff --git a/gdb/ppc-linux-tdep.c b/gdb/ppc-linux-tdep.c
index e2e1b1e..6df2411 100644
--- a/gdb/ppc-linux-tdep.c
+++ b/gdb/ppc-linux-tdep.c
@@ -332,7 +332,7 @@ ppc_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 {
   unsigned int insnbuf[POWERPC32_PLT_CHECK_LEN];
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR target = 0;
   int scan_limit, i;
@@ -898,7 +898,7 @@ ppc_linux_vsxregset (void)
 const struct regset *
 ppc_linux_cgprregset (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->wordsize == 4)
     {
@@ -938,7 +938,7 @@ ppc_linux_collect_core_cpgrregset (const struct regset *regset,
 				   int regnum, void *buf, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   const struct regset *cgprregset = ppc_linux_cgprregset (gdbarch);
 
@@ -985,7 +985,7 @@ ppc_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					void *cb_data,
 					const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int have_altivec = tdep->ppc_vr0_regnum != -1;
   int have_vsx = tdep->ppc_vsr0_upper_regnum != -1;
   int have_ppr = tdep->ppc_ppr_regnum != -1;
@@ -1170,7 +1170,7 @@ ppc_linux_sigtramp_cache (struct frame_info *this_frame,
   CORE_ADDR fpregs;
   int i;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   base = get_frame_register_unsigned (this_frame,
@@ -1341,7 +1341,7 @@ ppc_linux_get_syscall_number (struct gdbarch *gdbarch,
 			      thread_info *thread)
 {
   struct regcache *regcache = get_thread_regcache (thread);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   /* Make sure we're in a 32- or 64-bit machine */
@@ -1417,7 +1417,7 @@ static int
 ppc_linux_syscall_record (struct regcache *regcache)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST scnum;
   enum gdb_syscall syscall_gdb;
   int ret;
@@ -1506,7 +1506,7 @@ ppc_linux_record_signal (struct gdbarch *gdbarch, struct regcache *regcache,
   const int SIGNAL_FRAMESIZE = 128;
   const int sizeof_rt_sigframe = 1440 * 2 + 8 * 2 + 4 * 6 + 8 + 8 + 128 + 512;
   ULONGEST sp;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int i;
 
   for (i = 3; i <= 12; i++)
@@ -2018,7 +2018,7 @@ static void
 ppc_linux_init_abi (struct gdbarch_info info,
 		    struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct tdesc_arch_data *tdesc_data = info.tdesc_data;
   static const char *const stap_integer_prefixes[] = { "i", NULL };
   static const char *const stap_register_indirection_prefixes[] = { "(",
diff --git a/gdb/ppc-netbsd-tdep.c b/gdb/ppc-netbsd-tdep.c
index 31f1199..97912eb 100644
--- a/gdb/ppc-netbsd-tdep.c
+++ b/gdb/ppc-netbsd-tdep.c
@@ -102,7 +102,7 @@ ppcnbsd_sigtramp_cache_init (const struct tramp_frame *self,
 			     CORE_ADDR func)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR addr, base;
   int i;
 
diff --git a/gdb/ppc-obsd-tdep.c b/gdb/ppc-obsd-tdep.c
index 98b3e40..6a83c08 100644
--- a/gdb/ppc-obsd-tdep.c
+++ b/gdb/ppc-obsd-tdep.c
@@ -161,7 +161,7 @@ static struct trad_frame_cache *
 ppcobsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct trad_frame_cache *cache;
   CORE_ADDR addr, base, func;
diff --git a/gdb/ppc-sysv-tdep.c b/gdb/ppc-sysv-tdep.c
index d98af25..0d15e42 100644
--- a/gdb/ppc-sysv-tdep.c
+++ b/gdb/ppc-sysv-tdep.c
@@ -65,7 +65,7 @@ ppc_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 			      function_call_return_method return_method,
 			      CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int opencl_abi = ppc_sysv_use_opencl_abi (value_type (function));
   ULONGEST saved_sp;
@@ -597,7 +597,7 @@ get_decimal_float_return_value (struct gdbarch *gdbarch, struct type *valtype,
 				struct regcache *regcache, gdb_byte *readbuf,
 				const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (valtype->code () == TYPE_CODE_DECFLOAT);
 
@@ -675,7 +675,7 @@ do_ppc_sysv_return_value (struct gdbarch *gdbarch, struct type *func_type,
 			  gdb_byte *readbuf, const gdb_byte *writebuf,
 			  int broken_gcc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int opencl_abi = func_type? ppc_sysv_use_opencl_abi (func_type) : 0;
 
@@ -1250,7 +1250,7 @@ ppc64_sysv_abi_push_val (struct gdbarch *gdbarch,
 			 const bfd_byte *val, int len, int align,
 			 struct ppc64_sysv_argpos *argpos)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int offset = 0;
 
   /* Enforce alignment of stack location, if requested.  */
@@ -1300,7 +1300,7 @@ static void
 ppc64_sysv_abi_push_integer (struct gdbarch *gdbarch, ULONGEST val,
 			     struct ppc64_sysv_argpos *argpos)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   gdb_byte buf[PPC_MAX_REGISTER_SIZE];
 
@@ -1318,7 +1318,7 @@ ppc64_sysv_abi_push_freg (struct gdbarch *gdbarch,
 			  struct type *type, const bfd_byte *val,
 			  struct ppc64_sysv_argpos *argpos)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep->soft_float)
     return;
 
@@ -1403,7 +1403,7 @@ static void
 ppc64_sysv_abi_push_vreg (struct gdbarch *gdbarch, const bfd_byte *val,
 			  struct ppc64_sysv_argpos *argpos)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (argpos->regcache && argpos->vreg <= 13)
     argpos->regcache->cooked_write (tdep->ppc_vr0_regnum + argpos->vreg, val);
@@ -1419,7 +1419,7 @@ ppc64_sysv_abi_push_param (struct gdbarch *gdbarch,
 			   struct type *type, const bfd_byte *val,
 			   struct ppc64_sysv_argpos *argpos)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (type->code () == TYPE_CODE_FLT
       || type->code () == TYPE_CODE_DECFLOAT)
@@ -1545,7 +1545,7 @@ ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch,
 				CORE_ADDR struct_addr)
 {
   CORE_ADDR func_addr = find_function_addr (function, NULL);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int opencl_abi = ppc_sysv_use_opencl_abi (value_type (function));
   ULONGEST back_chain;
@@ -1739,7 +1739,7 @@ ppc64_sysv_abi_return_value_base (struct gdbarch *gdbarch, struct type *valtype,
 				  struct regcache *regcache, gdb_byte *readbuf,
 				  const gdb_byte *writebuf, int index)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Integers live in GPRs starting at r3.  */
   if ((valtype->code () == TYPE_CODE_INT
@@ -1905,7 +1905,7 @@ ppc64_sysv_abi_return_value (struct gdbarch *gdbarch, struct value *function,
 			     struct type *valtype, struct regcache *regcache,
 			     gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct type *func_type = function ? value_type (function) : NULL;
   int opencl_abi = func_type? ppc_sysv_use_opencl_abi (func_type) : 0;
   struct type *eltype;
diff --git a/gdb/ppc-tdep.h b/gdb/ppc-tdep.h
index 1e0754f..6b305c4 100644
--- a/gdb/ppc-tdep.h
+++ b/gdb/ppc-tdep.h
@@ -205,106 +205,106 @@ enum powerpc_long_double_abi
   POWERPC_LONG_DOUBLE_LAST
 };
 
-struct gdbarch_tdep
+struct ppc_gdbarch_tdep : gdbarch_tdep
   {
-    int wordsize;		/* Size in bytes of fixed-point word.  */
-    int soft_float;		/* Avoid FP registers for arguments?  */
+    int wordsize = 0;		/* Size in bytes of fixed-point word.  */
+    int soft_float = 0;		/* Avoid FP registers for arguments?  */
 
-    enum powerpc_elf_abi elf_abi;	/* ELF ABI version.  */
+    enum powerpc_elf_abi elf_abi {};	/* ELF ABI version.  */
 
     /* Format to use for the "long double" data type.  */
-    enum powerpc_long_double_abi long_double_abi;
+    enum powerpc_long_double_abi long_double_abi {};
 
     /* How to pass vector arguments.  Never set to AUTO or LAST.  */
-    enum powerpc_vector_abi vector_abi;
+    enum powerpc_vector_abi vector_abi {};
 
-    int ppc_gp0_regnum;		/* GPR register 0 */
-    int ppc_toc_regnum;		/* TOC register */
-    int ppc_ps_regnum;	        /* Processor (or machine) status (%msr) */
-    int ppc_cr_regnum;		/* Condition register */
-    int ppc_lr_regnum;		/* Link register */
-    int ppc_ctr_regnum;		/* Count register */
-    int ppc_xer_regnum;		/* Integer exception register */
+    int ppc_gp0_regnum = 0;		/* GPR register 0 */
+    int ppc_toc_regnum = 0;		/* TOC register */
+    int ppc_ps_regnum = 0;		/* Processor (or machine) status (%msr) */
+    int ppc_cr_regnum = 0;		/* Condition register */
+    int ppc_lr_regnum = 0;		/* Link register */
+    int ppc_ctr_regnum = 0;		/* Count register */
+    int ppc_xer_regnum = 0;		/* Integer exception register */
 
     /* Not all PPC and RS6000 variants will have the registers
        represented below.  A -1 is used to indicate that the register
        is not present in this variant.  */
 
     /* Floating-point registers.  */
-    int ppc_fp0_regnum;         /* Floating-point register 0.  */
-    int ppc_fpscr_regnum;	/* fp status and condition register.  */
+    int ppc_fp0_regnum = 0;	/* Floating-point register 0.  */
+    int ppc_fpscr_regnum = 0;	/* fp status and condition register.  */
 
     /* Multiplier-Quotient Register (older POWER architectures only).  */
-    int ppc_mq_regnum;
+    int ppc_mq_regnum = 0;
 
     /* POWER7 VSX registers.  */
-    int ppc_vsr0_regnum;	/* First VSX register.  */
-    int ppc_vsr0_upper_regnum;  /* First right most dword vsx register.  */
-    int ppc_efpr0_regnum;	/* First Extended FP register.  */
+    int ppc_vsr0_regnum = 0;		/* First VSX register.  */
+    int ppc_vsr0_upper_regnum = 0; 	/* First right most dword vsx register.  */
+    int ppc_efpr0_regnum = 0;		/* First Extended FP register.  */
 
     /* Altivec registers.  */
-    int ppc_vr0_regnum;		/* First AltiVec register.  */
-    int ppc_vrsave_regnum;	/* Last AltiVec register.  */
+    int ppc_vr0_regnum = 0;	/* First AltiVec register.  */
+    int ppc_vrsave_regnum = 0;	/* Last AltiVec register.  */
 
     /* Altivec pseudo-register vX aliases for the raw vrX
        registers.  */
-    int ppc_v0_alias_regnum;
+    int ppc_v0_alias_regnum = 0;
 
     /* SPE registers.  */
-    int ppc_ev0_upper_regnum;   /* First GPR upper half register.  */
-    int ppc_ev0_regnum;         /* First ev register.  */
-    int ppc_acc_regnum;         /* SPE 'acc' register.  */
-    int ppc_spefscr_regnum;     /* SPE 'spefscr' register.  */
+    int ppc_ev0_upper_regnum = 0;   /* First GPR upper half register.  */
+    int ppc_ev0_regnum = 0;         /* First ev register.  */
+    int ppc_acc_regnum = 0;         /* SPE 'acc' register.  */
+    int ppc_spefscr_regnum = 0;     /* SPE 'spefscr' register.  */
 
     /* Program Priority Register.  */
-    int ppc_ppr_regnum;
+    int ppc_ppr_regnum = 0;
 
     /* Data Stream Control Register.  */
-    int ppc_dscr_regnum;
+    int ppc_dscr_regnum = 0;
 
     /* Target Address Register.  */
-    int ppc_tar_regnum;
+    int ppc_tar_regnum = 0;
 
     /* Decimal 128 registers.  */
-    int ppc_dl0_regnum;		/* First Decimal128 argument register pair.  */
+    int ppc_dl0_regnum = 0;	/* First Decimal128 argument register pair.  */
 
-    int have_ebb;
+    int have_ebb = 0;
 
     /* PMU registers.  */
-    int ppc_mmcr0_regnum;
-    int ppc_mmcr2_regnum;
-    int ppc_siar_regnum;
-    int ppc_sdar_regnum;
-    int ppc_sier_regnum;
+    int ppc_mmcr0_regnum = 0;
+    int ppc_mmcr2_regnum = 0;
+    int ppc_siar_regnum = 0;
+    int ppc_sdar_regnum = 0;
+    int ppc_sier_regnum = 0;
 
     /* Hardware Transactional Memory registers.  */
-    int have_htm_spr;
-    int have_htm_core;
-    int have_htm_fpu;
-    int have_htm_altivec;
-    int have_htm_vsx;
-    int ppc_cppr_regnum;
-    int ppc_cdscr_regnum;
-    int ppc_ctar_regnum;
+    int have_htm_spr = 0;
+    int have_htm_core = 0;
+    int have_htm_fpu = 0;
+    int have_htm_altivec = 0;
+    int have_htm_vsx = 0;
+    int ppc_cppr_regnum = 0;
+    int ppc_cdscr_regnum = 0;
+    int ppc_ctar_regnum = 0;
 
     /* HTM pseudo registers.  */
-    int ppc_cdl0_regnum;
-    int ppc_cvsr0_regnum;
-    int ppc_cefpr0_regnum;
+    int ppc_cdl0_regnum = 0;
+    int ppc_cvsr0_regnum = 0;
+    int ppc_cefpr0_regnum = 0;
 
     /* Offset to ABI specific location where link register is saved.  */
-    int lr_frame_offset;	
+    int lr_frame_offset = 0;
 
     /* An array of integers, such that sim_regno[I] is the simulator
        register number for GDB register number I, or -1 if the
        simulator does not implement that register.  */
-    int *sim_regno;
+    int *sim_regno = nullptr;
 
     /* ISA-specific types.  */
-    struct type *ppc_builtin_type_vec64;
-    struct type *ppc_builtin_type_vec128;
+    struct type *ppc_builtin_type_vec64 = nullptr;
+    struct type *ppc_builtin_type_vec128 = nullptr;
 
-    int (*ppc_syscall_record) (struct regcache *regcache);
+    int (*ppc_syscall_record) (struct regcache *regcache) = nullptr;
 };
 
 
diff --git a/gdb/ppc64-tdep.c b/gdb/ppc64-tdep.c
index 1dd94f2..aab893d 100644
--- a/gdb/ppc64-tdep.c
+++ b/gdb/ppc64-tdep.c
@@ -89,7 +89,7 @@ ppc64_plt_entry_point (struct frame_info *frame, CORE_ADDR plt_off)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR tocp;
 
   if (execution_direction == EXEC_REVERSE)
diff --git a/gdb/riscv-linux-tdep.c b/gdb/riscv-linux-tdep.c
index 7351e19..f6489ab 100644
--- a/gdb/riscv-linux-tdep.c
+++ b/gdb/riscv-linux-tdep.c
@@ -179,7 +179,7 @@ riscv_linux_syscall_next_pc (struct frame_info *frame)
 static void
 riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index bfd93c6..a6a64d3 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -730,7 +730,8 @@ show_riscv_debug_variable (struct ui_file *file, int from_tty,
 int
 riscv_isa_xlen (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->isa_features.xlen;
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->isa_features.xlen;
 }
 
 /* See riscv-tdep.h.  */
@@ -738,7 +739,8 @@ riscv_isa_xlen (struct gdbarch *gdbarch)
 int
 riscv_abi_xlen (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->abi_features.xlen;
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->abi_features.xlen;
 }
 
 /* See riscv-tdep.h.  */
@@ -746,7 +748,8 @@ riscv_abi_xlen (struct gdbarch *gdbarch)
 int
 riscv_isa_flen (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->isa_features.flen;
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->isa_features.flen;
 }
 
 /* See riscv-tdep.h.  */
@@ -754,7 +757,8 @@ riscv_isa_flen (struct gdbarch *gdbarch)
 int
 riscv_abi_flen (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->abi_features.flen;
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->abi_features.flen;
 }
 
 /* See riscv-tdep.h.  */
@@ -762,7 +766,8 @@ riscv_abi_flen (struct gdbarch *gdbarch)
 bool
 riscv_abi_embedded (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->abi_features.embedded;
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->abi_features.embedded;
 }
 
 /* Return true if the target for GDBARCH has floating point hardware.  */
@@ -778,7 +783,8 @@ riscv_has_fp_regs (struct gdbarch *gdbarch)
 static bool
 riscv_has_fp_abi (struct gdbarch *gdbarch)
 {
-  return gdbarch_tdep (gdbarch)->abi_features.flen > 0;
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  return tdep->abi_features.flen > 0;
 }
 
 /* Return true if REGNO is a floating pointer register.  */
@@ -901,7 +907,7 @@ riscv_register_name (struct gdbarch *gdbarch, int regnum)
      will show up in 'info register all'.  Unless, we identify the
      duplicate copies of these registers (in riscv_tdesc_unknown_reg) and
      then hide the registers here by giving them no name.  */
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep->duplicate_fflags_regnum == regnum)
     return NULL;
   if (tdep->duplicate_frm_regnum == regnum)
@@ -929,7 +935,7 @@ riscv_register_name (struct gdbarch *gdbarch, int regnum)
 static struct type *
 riscv_fpreg_d_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->riscv_fpreg_d_type == nullptr)
     {
@@ -1251,7 +1257,7 @@ riscv_is_regnum_a_named_csr (int regnum)
 static bool
 riscv_is_unknown_csr (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   return (regnum >= tdep->unknown_csrs_first_regnum
 	  && regnum < (tdep->unknown_csrs_first_regnum
 		       + tdep->unknown_csrs_count));
@@ -3560,7 +3566,7 @@ riscv_tdesc_unknown_reg (struct gdbarch *gdbarch, tdesc_feature *feature,
      record their register numbers here.  */
   if (strcmp (tdesc_feature_name (feature), riscv_freg_feature.name ()) == 0)
     {
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       int *regnum_ptr = nullptr;
 
       if (strcmp (reg_name, "fflags") == 0)
@@ -3591,7 +3597,7 @@ riscv_tdesc_unknown_reg (struct gdbarch *gdbarch, tdesc_feature *feature,
      about register groups in riscv_register_reggroup_p.  */
   if (strcmp (tdesc_feature_name (feature), riscv_csr_feature.name ()) == 0)
     {
-      struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+      riscv_gdbarch_tdep *tdep = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       if (tdep->unknown_csrs_first_regnum == -1)
 	tdep->unknown_csrs_first_regnum = possible_regnum;
       gdb_assert (tdep->unknown_csrs_first_regnum
@@ -3628,7 +3634,6 @@ riscv_gdbarch_init (struct gdbarch_info info,
 		    struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   struct riscv_gdbarch_features features;
   const struct target_desc *tdesc = info.target_desc;
 
@@ -3693,7 +3698,8 @@ riscv_gdbarch_init (struct gdbarch_info info,
       /* Check that the feature set of the ARCHES matches the feature set
 	 we are looking for.  If it doesn't then we can't reuse this
 	 gdbarch.  */
-      struct gdbarch_tdep *other_tdep = gdbarch_tdep (arches->gdbarch);
+      riscv_gdbarch_tdep *other_tdep
+	= (riscv_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
 
       if (other_tdep->isa_features != features
 	  || other_tdep->abi_features != abi_features)
@@ -3706,7 +3712,7 @@ riscv_gdbarch_init (struct gdbarch_info info,
     return arches->gdbarch;
 
   /* None found, so create a new architecture from the information provided.  */
-  tdep = new (struct gdbarch_tdep);
+  riscv_gdbarch_tdep *tdep = new riscv_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->isa_features = features;
   tdep->abi_features = abi_features;
@@ -3812,7 +3818,8 @@ static CORE_ADDR
 riscv_next_pc (struct regcache *regcache, CORE_ADDR pc)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  const struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  const riscv_gdbarch_tdep *tdep
+    = (riscv_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct riscv_insn insn;
   CORE_ADDR next_pc;
 
diff --git a/gdb/riscv-tdep.h b/gdb/riscv-tdep.h
index 03870cf..2af6ec3 100644
--- a/gdb/riscv-tdep.h
+++ b/gdb/riscv-tdep.h
@@ -22,6 +22,7 @@
 #define RISCV_TDEP_H
 
 #include "arch/riscv.h"
+#include "gdbarch.h"
 
 /* RiscV register numbers.  */
 enum
@@ -75,7 +76,7 @@ enum
 };
 
 /* RISC-V specific per-architecture information.  */
-struct gdbarch_tdep
+struct riscv_gdbarch_tdep : gdbarch_tdep
 {
   /* Features about the target hardware that impact how the gdbarch is
      configured.  Two gdbarch instances are compatible only if this field
@@ -105,7 +106,7 @@ struct gdbarch_tdep
 
   /* Return the expected next PC assuming FRAME is stopped at a syscall
      instruction.  */
-  CORE_ADDR (*syscall_next_pc) (struct frame_info *frame);
+  CORE_ADDR (*syscall_next_pc) (struct frame_info *frame) = nullptr;
 };
 
 
diff --git a/gdb/rl78-tdep.c b/gdb/rl78-tdep.c
index 3b2cf96..616dafb 100644
--- a/gdb/rl78-tdep.c
+++ b/gdb/rl78-tdep.c
@@ -209,21 +209,21 @@ enum
 
 /* Architecture specific data.  */
 
-struct gdbarch_tdep
+struct rl78_gdbarch_tdep : gdbarch_tdep
 {
   /* The ELF header flags specify the multilib used.  */
-  int elf_flags;
+  int elf_flags = 0;
 
-  struct type *rl78_void,
-	      *rl78_uint8,
-	      *rl78_int8,
-	      *rl78_uint16,
-	      *rl78_int16,
-	      *rl78_uint32,
-	      *rl78_int32,
-	      *rl78_data_pointer,
-	      *rl78_code_pointer,
-	      *rl78_psw_type;
+  struct type *rl78_void = nullptr,
+	      *rl78_uint8 = nullptr,
+	      *rl78_int8 = nullptr,
+	      *rl78_uint16 = nullptr,
+	      *rl78_int16 = nullptr,
+	      *rl78_uint32 = nullptr,
+	      *rl78_int32 = nullptr,
+	      *rl78_data_pointer = nullptr,
+	      *rl78_code_pointer = nullptr,
+	      *rl78_psw_type = nullptr;
 };
 
 /* This structure holds the results of a prologue analysis.  */
@@ -266,7 +266,7 @@ struct rl78_prologue
 static struct type *
 rl78_psw_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  rl78_gdbarch_tdep *tdep = (rl78_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->rl78_psw_type == NULL)
     {
@@ -290,7 +290,7 @@ rl78_psw_type (struct gdbarch *gdbarch)
 static struct type *
 rl78_register_type (struct gdbarch *gdbarch, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  rl78_gdbarch_tdep *tdep = (rl78_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (reg_nr == RL78_PC_REGNUM)
     return tdep->rl78_code_pointer;
@@ -1247,7 +1247,8 @@ rl78_return_value (struct gdbarch *gdbarch,
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   ULONGEST valtype_len = TYPE_LENGTH (valtype);
-  int is_g10 = gdbarch_tdep (gdbarch)->elf_flags & E_FLAG_RL78_G10;
+  rl78_gdbarch_tdep *tdep = (rl78_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int is_g10 = tdep->elf_flags & E_FLAG_RL78_G10;
 
   if (valtype_len > 8)
     return RETURN_VALUE_STRUCT_CONVENTION;
@@ -1375,7 +1376,6 @@ static struct gdbarch *
 rl78_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int elf_flags;
 
   /* Extract the elf_flags if available.  */
@@ -1392,7 +1392,10 @@ rl78_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      if (gdbarch_tdep (arches->gdbarch)->elf_flags != elf_flags)
+      rl78_gdbarch_tdep *tdep
+	= (rl78_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
+      if (tdep->elf_flags != elf_flags)
 	continue;
 
       return arches->gdbarch;
@@ -1400,7 +1403,7 @@ rl78_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* None found, create a new architecture from the information
      provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  rl78_gdbarch_tdep * tdep = new rl78_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->elf_flags = elf_flags;
 
diff --git a/gdb/rs6000-aix-tdep.c b/gdb/rs6000-aix-tdep.c
index 80e1957..11cae6a 100644
--- a/gdb/rs6000-aix-tdep.c
+++ b/gdb/rs6000-aix-tdep.c
@@ -73,7 +73,7 @@ aix_sighandle_frame_cache (struct frame_info *this_frame,
   LONGEST backchain;
   CORE_ADDR base, base_orig, func;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct trad_frame_cache *this_trad_cache;
 
@@ -259,7 +259,8 @@ rs6000_aix_iterate_over_regset_sections (struct gdbarch *gdbarch,
 					 void *cb_data,
 					 const struct regcache *regcache)
 {
-  if (gdbarch_tdep (gdbarch)->wordsize == 4)
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->wordsize == 4)
     cb (".reg", 592, 592, &rs6000_aix32_regset, NULL, cb_data);
   else
     cb (".reg", 576, 576, &rs6000_aix64_regset, NULL, cb_data);
@@ -289,7 +290,7 @@ rs6000_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 			function_call_return_method return_method,
 			CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int ii;
   int len = 0;
@@ -297,7 +298,7 @@ rs6000_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int argbytes;			/* current argument byte */
   gdb_byte tmp_buffer[50];
   int f_argno = 0;		/* current floating point argno */
-  int wordsize = gdbarch_tdep (gdbarch)->wordsize;
+  int wordsize = tdep->wordsize;
   CORE_ADDR func_addr = find_function_addr (function, NULL);
 
   struct value *arg = 0;
@@ -519,7 +520,7 @@ rs6000_return_value (struct gdbarch *gdbarch, struct value *function,
 		     struct type *valtype, struct regcache *regcache,
 		     gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   /* The calling convention this function implements assumes the
@@ -657,7 +658,7 @@ rs6000_convert_from_func_ptr_addr (struct gdbarch *gdbarch,
 				   CORE_ADDR addr,
 				   struct target_ops *targ)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct obj_section *s;
 
@@ -701,7 +702,7 @@ branch_dest (struct regcache *regcache, int opcode, int instr,
 	     CORE_ADDR pc, CORE_ADDR safety)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR dest;
   int immediate;
@@ -969,7 +970,7 @@ static struct ld_info
 rs6000_aix_extract_ld_info (struct gdbarch *gdbarch,
 			    const gdb_byte *ldi_buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
   const struct ld_info_desc desc
@@ -1128,7 +1129,7 @@ rs6000_aix_core_xfer_shared_libraries_aix (struct gdbarch *gdbarch,
 static void
 rs6000_aix_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* RS6000/AIX does not support PT_STEP.  Has to be simulated.  */
   set_gdbarch_software_single_step (gdbarch, rs6000_software_single_step);
diff --git a/gdb/rs6000-lynx178-tdep.c b/gdb/rs6000-lynx178-tdep.c
index 21f1baf..bdc1aaa 100644
--- a/gdb/rs6000-lynx178-tdep.c
+++ b/gdb/rs6000-lynx178-tdep.c
@@ -36,7 +36,7 @@ rs6000_lynx178_push_dummy_call (struct gdbarch *gdbarch,
 				function_call_return_method return_method,
 				CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int ii;
   int len = 0;
@@ -44,7 +44,7 @@ rs6000_lynx178_push_dummy_call (struct gdbarch *gdbarch,
   int argbytes;			/* current argument byte */
   gdb_byte tmp_buffer[50];
   int f_argno = 0;		/* current floating point argno */
-  int wordsize = gdbarch_tdep (gdbarch)->wordsize;
+  int wordsize = tdep->wordsize;
 
   struct value *arg = 0;
   struct type *type;
@@ -265,7 +265,7 @@ rs6000_lynx178_return_value (struct gdbarch *gdbarch, struct value *function,
 			     struct type *valtype, struct regcache *regcache,
 			     gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   /* The calling convention this function implements assumes the
diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index 4830ed2..0d61894 100644
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -209,7 +209,7 @@ struct rs6000_framedata
 int
 vsx_register_p (struct gdbarch *gdbarch, int regno)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep->ppc_vsr0_regnum < 0)
     return 0;
   else
@@ -221,7 +221,7 @@ vsx_register_p (struct gdbarch *gdbarch, int regno)
 int
 altivec_register_p (struct gdbarch *gdbarch, int regno)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep->ppc_vr0_regnum < 0 || tdep->ppc_vrsave_regnum < 0)
     return 0;
   else
@@ -233,7 +233,7 @@ altivec_register_p (struct gdbarch *gdbarch, int regno)
 int
 spe_register_p (struct gdbarch *gdbarch, int regno)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   
   /* Is it a reference to EV0 -- EV31, and do we have those?  */
   if (IS_SPE_PSEUDOREG (tdep, regno))
@@ -265,7 +265,7 @@ spe_register_p (struct gdbarch *gdbarch, int regno)
 int
 ppc_floating_point_unit_p (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   return (tdep->ppc_fp0_regnum >= 0
 	  && tdep->ppc_fpscr_regnum >= 0);
@@ -276,7 +276,7 @@ ppc_floating_point_unit_p (struct gdbarch *gdbarch)
 int
 ppc_altivec_support_p (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   return (tdep->ppc_vr0_regnum >= 0
 	  && tdep->ppc_vrsave_regnum >= 0);
@@ -305,7 +305,7 @@ set_sim_regno (int *table, int gdb_regno, int sim_regno)
 static void
 init_sim_regno_table (struct gdbarch *arch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (arch);
   int total_regs = gdbarch_num_regs (arch);
   int *sim_regno = GDBARCH_OBSTACK_CALLOC (arch, total_regs, int);
   int i;
@@ -399,7 +399,7 @@ init_sim_regno_table (struct gdbarch *arch)
 static int
 rs6000_register_sim_regno (struct gdbarch *gdbarch, int reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int sim_regno;
 
   if (tdep->sim_regno == NULL)
@@ -470,7 +470,7 @@ ppc_collect_reg (const struct regcache *regcache, int regnum,
     
 static int
 ppc_greg_offset (struct gdbarch *gdbarch,
-		 struct gdbarch_tdep *tdep,
+		 ppc_gdbarch_tdep *tdep,
 		 const struct ppc_reg_offsets *offsets,
 		 int regnum,
 		 int *regsize)
@@ -507,7 +507,7 @@ ppc_greg_offset (struct gdbarch *gdbarch,
 }
 
 static int
-ppc_fpreg_offset (struct gdbarch_tdep *tdep,
+ppc_fpreg_offset (ppc_gdbarch_tdep *tdep,
 		  const struct ppc_reg_offsets *offsets,
 		  int regnum)
 {
@@ -530,7 +530,7 @@ ppc_supply_gregset (const struct regset *regset, struct regcache *regcache,
 		    int regnum, const void *gregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const struct ppc_reg_offsets *offsets
     = (const struct ppc_reg_offsets *) regset->regmap;
   size_t offset;
@@ -580,14 +580,13 @@ ppc_supply_fpregset (const struct regset *regset, struct regcache *regcache,
 		     int regnum, const void *fpregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep;
   const struct ppc_reg_offsets *offsets;
   size_t offset;
 
   if (!ppc_floating_point_unit_p (gdbarch))
     return;
 
-  tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   offsets = (const struct ppc_reg_offsets *) regset->regmap;
   if (regnum == -1)
     {
@@ -620,7 +619,7 @@ ppc_collect_gregset (const struct regset *regset,
 		     int regnum, void *gregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const struct ppc_reg_offsets *offsets
     = (const struct ppc_reg_offsets *) regset->regmap;
   size_t offset;
@@ -671,14 +670,13 @@ ppc_collect_fpregset (const struct regset *regset,
 		      int regnum, void *fpregs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep;
   const struct ppc_reg_offsets *offsets;
   size_t offset;
 
   if (!ppc_floating_point_unit_p (gdbarch))
     return;
 
-  tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   offsets = (const struct ppc_reg_offsets *) regset->regmap;
   if (regnum == -1)
     {
@@ -756,7 +754,7 @@ static int
 rs6000_in_function_epilogue_frame_p (struct frame_info *curfrm,
 				     struct gdbarch *gdbarch, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   bfd_byte insn_buf[PPC_INSN_SIZE];
   CORE_ADDR scan_pc, func_start, func_end, epilogue_start, epilogue_end;
@@ -1052,8 +1050,9 @@ ppc_displaced_step_fixup (struct gdbarch *gdbarch,
       if (insn & 0x1)
 	{
 	  /* Link register needs to be set to the next instruction's PC.  */
+	  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 	  regcache_cooked_write_unsigned (regs,
-					  gdbarch_tdep (gdbarch)->ppc_lr_regnum,
+					  tdep->ppc_lr_regnum,
 					  from + PPC_INSN_SIZE);
 	  displaced_debug_printf ("(ppc) adjusted LR to %s",
 				  paddress (gdbarch, from + PPC_INSN_SIZE));
@@ -1599,7 +1598,7 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
   int num_skip_non_prologue_insns = 0;
   int r0_contains_arg = 0;
   const struct bfd_arch_info *arch_info = gdbarch_bfd_arch_info (gdbarch);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
   memset (fdata, 0, sizeof (struct rs6000_framedata));
@@ -2319,7 +2318,7 @@ static CORE_ADDR
 rs6000_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   unsigned int ii, op;
   int rel;
@@ -2377,7 +2376,7 @@ rs6000_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 static struct type *
 rs6000_builtin_type_vec64 (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->ppc_builtin_type_vec64)
     {
@@ -2422,7 +2421,7 @@ rs6000_builtin_type_vec64 (struct gdbarch *gdbarch)
 static struct type *
 rs6000_builtin_type_vec128 (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->ppc_builtin_type_vec128)
     {
@@ -2476,7 +2475,7 @@ rs6000_builtin_type_vec128 (struct gdbarch *gdbarch)
 static const char *
 rs6000_register_name (struct gdbarch *gdbarch, int regno)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* The upper half "registers" have names in the XML description,
      but we present only the low GPRs and the full 64-bit registers
@@ -2614,7 +2613,7 @@ rs6000_register_name (struct gdbarch *gdbarch, int regno)
 static struct type *
 rs6000_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* These are the e500 pseudo-registers.  */
   if (IS_SPE_PSEUDOREG (tdep, regnum))
@@ -2653,7 +2652,7 @@ static int
 rs6000_pseudo_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 				   struct reggroup *group)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (IS_V_ALIAS_PSEUDOREG (tdep, regnum))
     return 0;
@@ -2668,7 +2667,7 @@ static int
 rs6000_convert_register_p (struct gdbarch *gdbarch, int regnum,
 			   struct type *type)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   return (tdep->ppc_fp0_regnum >= 0
 	  && regnum >= tdep->ppc_fp0_regnum
@@ -2753,7 +2752,7 @@ e500_move_ev_register (move_ev_register_func move,
 		       struct regcache *regcache, int ev_reg, void *buffer)
 {
   struct gdbarch *arch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch); 
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (arch);
   int reg_index;
   gdb_byte *byte_buffer = (gdb_byte *) buffer;
   enum register_status status;
@@ -2794,7 +2793,7 @@ e500_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int ev_reg, gdb_byte *buffer)
 {
   struct gdbarch *arch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index;
   enum register_status status;
 
@@ -2835,7 +2834,7 @@ static enum register_status
 dfp_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int reg_nr, gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, fp0;
   enum register_status status;
 
@@ -2875,7 +2874,7 @@ static void
 dfp_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
 			    int reg_nr, const gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, fp0;
 
   if (IS_DFP_PSEUDOREG (tdep, reg_nr))
@@ -2912,7 +2911,7 @@ v_alias_pseudo_register_read (struct gdbarch *gdbarch,
 			      readable_regcache *regcache, int reg_nr,
 			      gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_assert (IS_V_ALIAS_PSEUDOREG (tdep, reg_nr));
 
   return regcache->raw_read (tdep->ppc_vr0_regnum
@@ -2927,7 +2926,7 @@ v_alias_pseudo_register_write (struct gdbarch *gdbarch,
 			       struct regcache *regcache,
 			       int reg_nr, const gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_assert (IS_V_ALIAS_PSEUDOREG (tdep, reg_nr));
 
   regcache->raw_write (tdep->ppc_vr0_regnum
@@ -2939,7 +2938,7 @@ static enum register_status
 vsx_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int reg_nr, gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, vr0, fp0, vsr0_upper;
   enum register_status status;
 
@@ -2987,7 +2986,7 @@ static void
 vsx_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
 			    int reg_nr, const gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, vr0, fp0, vsr0_upper;
 
   if (IS_VSX_PSEUDOREG (tdep, reg_nr))
@@ -3029,7 +3028,7 @@ static enum register_status
 efp_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int reg_nr, gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, vr0;
 
   if (IS_EFP_PSEUDOREG (tdep, reg_nr))
@@ -3058,7 +3057,7 @@ static void
 efp_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
 			    int reg_nr, const gdb_byte *buffer)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, vr0;
   int offset = gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG ? 0 : 8;
 
@@ -3094,7 +3093,7 @@ rs6000_pseudo_register_read (struct gdbarch *gdbarch,
 			     int reg_nr, gdb_byte *buffer)
 {
   struct gdbarch *regcache_arch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (regcache_arch == gdbarch);
 
@@ -3125,7 +3124,7 @@ rs6000_pseudo_register_write (struct gdbarch *gdbarch,
 			      int reg_nr, const gdb_byte *buffer)
 {
   struct gdbarch *regcache_arch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   gdb_assert (regcache_arch == gdbarch);
 
@@ -3156,7 +3155,7 @@ static void
 dfp_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				struct agent_expr *ax, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, fp0;
 
   if (IS_DFP_PSEUDOREG (tdep, reg_nr))
@@ -3183,7 +3182,7 @@ static void
 v_alias_pseudo_register_collect (struct gdbarch *gdbarch,
 				 struct agent_expr *ax, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   gdb_assert (IS_V_ALIAS_PSEUDOREG (tdep, reg_nr));
 
   ax_reg_mask (ax, tdep->ppc_vr0_regnum
@@ -3197,7 +3196,7 @@ static void
 vsx_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				struct agent_expr *ax, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, vr0, fp0, vsr0_upper;
 
   if (IS_VSX_PSEUDOREG (tdep, reg_nr))
@@ -3235,7 +3234,7 @@ static void
 efp_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				struct agent_expr *ax, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int reg_index, vr0;
 
   if (IS_EFP_PSEUDOREG (tdep, reg_nr))
@@ -3258,7 +3257,7 @@ static int
 rs6000_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				   struct agent_expr *ax, int reg_nr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (IS_SPE_PSEUDOREG (tdep, reg_nr))
     {
       int reg_index = reg_nr - tdep->ppc_ev0_regnum;
@@ -3298,7 +3297,7 @@ rs6000_gen_return_address (struct gdbarch *gdbarch,
 			   struct agent_expr *ax, struct axs_value *value,
 			   CORE_ADDR scope)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   value->type = register_type (gdbarch, tdep->ppc_lr_regnum);
   value->kind = axs_lvalue_register;
   value->u.reg = tdep->ppc_lr_regnum;
@@ -3309,7 +3308,7 @@ rs6000_gen_return_address (struct gdbarch *gdbarch,
 static int
 rs6000_stab_reg_to_regnum (struct gdbarch *gdbarch, int num)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (0 <= num && num <= 31)
     return tdep->ppc_gp0_regnum + num;
@@ -3351,7 +3350,7 @@ rs6000_stab_reg_to_regnum (struct gdbarch *gdbarch, int num)
 static int
 rs6000_dwarf2_reg_to_regnum (struct gdbarch *gdbarch, int num)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (0 <= num && num <= 31)
     return tdep->ppc_gp0_regnum + num;
@@ -3570,7 +3569,7 @@ rs6000_frame_cache (struct frame_info *this_frame, void **this_cache)
 {
   struct rs6000_frame_cache *cache;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct rs6000_framedata fdata;
   int wordsize = tdep->wordsize;
@@ -3806,7 +3805,7 @@ rs6000_epilogue_frame_cache (struct frame_info *this_frame, void **this_cache)
 {
   struct rs6000_frame_cache *cache;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (*this_cache)
     return (struct rs6000_frame_cache *) *this_cache;
@@ -3927,7 +3926,7 @@ ppc_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
 			    struct dwarf2_frame_state_reg *reg,
 			    struct frame_info *this_frame)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* PPC32 and PPC64 ABI's are the same regarding volatile and
      non-volatile registers.  We will use the same code for both.  */
@@ -4139,7 +4138,7 @@ bfd_uses_spe_extensions (bfd *abfd)
    Otherwise, it's just a VR register.  Record them accordingly.  */
 
 static int
-ppc_record_vsr (struct regcache *regcache, struct gdbarch_tdep *tdep, int vsr)
+ppc_record_vsr (struct regcache *regcache, ppc_gdbarch_tdep *tdep, int vsr)
 {
   if (vsr < 0 || vsr >= 64)
     return -1;
@@ -4168,7 +4167,7 @@ static int
 ppc_process_record_op4 (struct gdbarch *gdbarch, struct regcache *regcache,
 			CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ext = PPC_FIELD (insn, 21, 11);
   int vra = PPC_FIELD (insn, 11, 5);
 
@@ -4541,7 +4540,7 @@ static int
 ppc_process_record_op19 (struct gdbarch *gdbarch, struct regcache *regcache,
 			   CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ext = PPC_EXTOP (insn);
 
   switch (ext & 0x01f)
@@ -4593,7 +4592,7 @@ static int
 ppc_process_record_op31 (struct gdbarch *gdbarch, struct regcache *regcache,
 			   CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ext = PPC_EXTOP (insn);
   int tmp, nr, nb, i;
   CORE_ADDR at_dcsz, ea = 0;
@@ -5190,7 +5189,7 @@ static int
 ppc_process_record_op59 (struct gdbarch *gdbarch, struct regcache *regcache,
 			   CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ext = PPC_EXTOP (insn);
 
   switch (ext & 0x1f)
@@ -5284,7 +5283,7 @@ static int
 ppc_process_record_op60 (struct gdbarch *gdbarch, struct regcache *regcache,
 			   CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ext = PPC_EXTOP (insn);
 
   switch (ext >> 2)
@@ -5646,7 +5645,7 @@ static int
 ppc_process_record_op61 (struct gdbarch *gdbarch, struct regcache *regcache,
 			   CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST ea = 0;
   int size;
 
@@ -5705,7 +5704,7 @@ static int
 ppc_process_record_op63 (struct gdbarch *gdbarch, struct regcache *regcache,
 			   CORE_ADDR addr, uint32_t insn)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ext = PPC_EXTOP (insn);
   int tmp;
 
@@ -5964,7 +5963,7 @@ int
 ppc_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
 		      CORE_ADDR addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   uint32_t insn;
   int op6, tmp, i;
@@ -6267,7 +6266,6 @@ static struct gdbarch *
 rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int wordsize, from_xcoff_exec, from_elf_exec;
   enum bfd_architecture arch;
   unsigned long mach;
@@ -6953,7 +6951,8 @@ rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
       /* Word size in the various PowerPC bfd_arch_info structs isn't
 	 meaningful, because 64-bit CPUs can run in 32-bit mode.  So, perform
 	 separate word size check.  */
-      tdep = gdbarch_tdep (arches->gdbarch);
+      ppc_gdbarch_tdep *tdep
+	= (ppc_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
       if (tdep && tdep->elf_abi != elf_abi)
 	continue;
       if (tdep && tdep->soft_float != soft_float)
@@ -6974,7 +6973,7 @@ rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        - "set arch"		trust blindly
        - GDB startup		useless but harmless */
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  ppc_gdbarch_tdep *tdep = new ppc_gdbarch_tdep;
   tdep->wordsize = wordsize;
   tdep->elf_abi = elf_abi;
   tdep->soft_float = soft_float;
@@ -7253,7 +7252,7 @@ rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 rs6000_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep == NULL)
     return;
diff --git a/gdb/rx-tdep.c b/gdb/rx-tdep.c
index 2d20aed..73e708b 100644
--- a/gdb/rx-tdep.c
+++ b/gdb/rx-tdep.c
@@ -68,16 +68,16 @@ enum rx_frame_type {
 };
 
 /* Architecture specific data.  */
-struct gdbarch_tdep
+struct rx_gdbarch_tdep : gdbarch_tdep
 {
   /* The ELF header flags specify the multilib used.  */
-  int elf_flags;
+  int elf_flags = 0;
 
   /* Type of PSW and BPSW.  */
-  struct type *rx_psw_type;
+  struct type *rx_psw_type = nullptr;
 
   /* Type of FPSW.  */
-  struct type *rx_fpsw_type;
+  struct type *rx_fpsw_type = nullptr;
 };
 
 /* This structure holds the results of a prologue analysis.  */
@@ -944,7 +944,6 @@ static struct gdbarch *
 rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int elf_flags;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -963,7 +962,10 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      if (gdbarch_tdep (arches->gdbarch)->elf_flags != elf_flags)
+      rx_gdbarch_tdep *tdep
+	= (rx_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
+      if (tdep->elf_flags != elf_flags)
 	continue;
 
       return arches->gdbarch;
@@ -994,7 +996,7 @@ rx_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   gdb_assert(tdesc_data != NULL);
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  rx_gdbarch_tdep *tdep = new rx_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   tdep->elf_flags = elf_flags;
 
diff --git a/gdb/s12z-tdep.c b/gdb/s12z-tdep.c
index faf63c4..ca4fe0a 100644
--- a/gdb/s12z-tdep.c
+++ b/gdb/s12z-tdep.c
@@ -482,7 +482,7 @@ constexpr gdb_byte s12z_break_insn[] = {0x00};
 
 typedef BP_MANIPULATION (s12z_break_insn) s12z_breakpoint;
 
-struct gdbarch_tdep
+struct s12z_gdbarch_tdep : gdbarch_tdep
 {
 };
 
@@ -640,7 +640,7 @@ show_bdccsr_command (const char *args, int from_tty)
 static struct gdbarch *
 s12z_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep = XNEW (struct gdbarch_tdep);
+  s12z_gdbarch_tdep *tdep = new s12z_gdbarch_tdep;
   struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
 
   add_cmd ("bdccsr", class_support, show_bdccsr_command,
diff --git a/gdb/s390-linux-tdep.c b/gdb/s390-linux-tdep.c
index 04e3fc6..3fa0b65 100644
--- a/gdb/s390-linux-tdep.c
+++ b/gdb/s390-linux-tdep.c
@@ -79,7 +79,7 @@ static void
 s390_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc);
 
@@ -269,7 +269,7 @@ s390_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				   void *cb_data,
 				   const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const int gregset_size = (tdep->abi == ABI_LINUX_S390 ?
 			    s390_sizeof_gregset : s390x_sizeof_gregset);
 
@@ -390,7 +390,7 @@ s390_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
 				  void **this_prologue_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int word_size = gdbarch_ptr_bit (gdbarch) / 8;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct s390_sigtramp_unwind_cache *info;
@@ -561,7 +561,7 @@ s390_linux_get_syscall_number (struct gdbarch *gdbarch,
 			       thread_info *thread)
 {
   struct regcache *regs = get_thread_regcache (thread);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   ULONGEST pc;
   ULONGEST svc_number = -1;
@@ -594,7 +594,7 @@ static int
 s390_all_but_pc_registers_record (struct regcache *regcache)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int i;
 
   for (i = 0; i < 16; i++)
@@ -802,7 +802,7 @@ static int
 s390_linux_syscall_record (struct regcache *regcache, LONGEST syscall_native)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int ret;
   enum gdb_syscall syscall_gdb;
 
@@ -852,7 +852,7 @@ static int
 s390_linux_record_signal (struct gdbarch *gdbarch, struct regcache *regcache,
 			  enum gdb_signal signal)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   /* There are two kinds of signal frames on s390. rt_sigframe is always
      the larger one, so don't even bother with sigframe.  */
   const int sizeof_rt_sigframe = (tdep->abi == ABI_LINUX_ZSERIES ?
@@ -1116,7 +1116,7 @@ s390_init_linux_record_tdep (struct linux_record_tdep *record_tdep,
 static void
 s390_linux_init_abi_any (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->s390_syscall_record = s390_linux_syscall_record;
 
@@ -1151,7 +1151,7 @@ s390_linux_init_abi_any (struct gdbarch_info info, struct gdbarch *gdbarch)
 static void
 s390_linux_init_abi_31 (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->abi = ABI_LINUX_S390;
 
@@ -1167,7 +1167,7 @@ s390_linux_init_abi_31 (struct gdbarch_info info, struct gdbarch *gdbarch)
 static void
 s390_linux_init_abi_64 (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->abi = ABI_LINUX_ZSERIES;
 
diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c
index 0a4a574..abbb094 100644
--- a/gdb/s390-tdep.c
+++ b/gdb/s390-tdep.c
@@ -1045,7 +1045,7 @@ s390_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 static int
 s390_register_call_saved (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   switch (tdep->abi)
     {
@@ -1076,7 +1076,7 @@ s390_guess_tracepoint_registers (struct gdbarch *gdbarch,
 				 struct regcache *regcache,
 				 CORE_ADDR addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int sz = register_size (gdbarch, S390_PSWA_REGNUM);
   gdb_byte *reg = (gdb_byte *) alloca (sz);
   ULONGEST pswm, pswa;
@@ -1172,7 +1172,7 @@ enum { s390_dwarf_reg_r0l = ARRAY_SIZE (s390_dwarf_regmap) - 16 };
 static int
 s390_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int gdb_reg = -1;
 
   /* In a 32-on-64 debug scenario, debug info refers to the full
@@ -1205,7 +1205,7 @@ s390_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
    These pseudo-registers are composed of two adjacent gprs.  */
 
 static int
-regnum_is_gpr_full (struct gdbarch_tdep *tdep, int regnum)
+regnum_is_gpr_full (s390_gdbarch_tdep *tdep, int regnum)
 {
   return (tdep->gpr_full_regnum != -1
 	  && regnum >= tdep->gpr_full_regnum
@@ -1216,7 +1216,7 @@ regnum_is_gpr_full (struct gdbarch_tdep *tdep, int regnum)
    These pseudo-registers are composed of f0-f15 and v0l-v15l.  */
 
 static int
-regnum_is_vxr_full (struct gdbarch_tdep *tdep, int regnum)
+regnum_is_vxr_full (s390_gdbarch_tdep *tdep, int regnum)
 {
   return (tdep->v0_full_regnum != -1
 	  && regnum >= tdep->v0_full_regnum
@@ -1231,7 +1231,7 @@ static struct value *
 s390_value_from_register (struct gdbarch *gdbarch, struct type *type,
 			  int regnum, struct frame_id frame_id)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct value *value = default_value_from_register (gdbarch, type,
 						     regnum, frame_id);
   check_typedef (type);
@@ -1250,7 +1250,7 @@ s390_value_from_register (struct gdbarch *gdbarch, struct type *type,
 static const char *
 s390_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (regnum == tdep->pc_regnum)
     return "pc";
@@ -1284,7 +1284,7 @@ s390_pseudo_register_name (struct gdbarch *gdbarch, int regnum)
 static struct type *
 s390_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (regnum == tdep->pc_regnum)
     return builtin_type (gdbarch)->builtin_func_ptr;
@@ -1308,7 +1308,7 @@ static enum register_status
 s390_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 			   int regnum, gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int regsize = register_size (gdbarch, regnum);
   ULONGEST val;
@@ -1383,7 +1383,7 @@ static void
 s390_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
 			    int regnum, const gdb_byte *buf)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int regsize = register_size (gdbarch, regnum);
   ULONGEST val, psw;
@@ -1442,7 +1442,7 @@ static int
 s390_pseudo_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 				 struct reggroup *group)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* We usually save/restore the whole PSW, which includes PC and CC.
      However, some older gdbservers may not support saving/restoring
@@ -1470,7 +1470,7 @@ static int
 s390_ax_pseudo_register_collect (struct gdbarch *gdbarch,
 				 struct agent_expr *ax, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (regnum == tdep->pc_regnum)
     {
       ax_reg_mask (ax, S390_PSWA_REGNUM);
@@ -1504,7 +1504,7 @@ static int
 s390_ax_pseudo_register_push_stack (struct gdbarch *gdbarch,
 				    struct agent_expr *ax, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (regnum == tdep->pc_regnum)
     {
       ax_reg (ax, S390_PSWA_REGNUM);
@@ -1746,7 +1746,7 @@ struct s390_arg_state
 
 static void
 s390_handle_arg (struct s390_arg_state *as, struct value *arg,
-		 struct gdbarch_tdep *tdep, int word_size,
+		 s390_gdbarch_tdep *tdep, int word_size,
 		 enum bfd_endian byte_order, int is_unnamed)
 {
   struct type *type = check_typedef (value_type (arg));
@@ -1905,7 +1905,7 @@ s390_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 		      function_call_return_method return_method,
 		      CORE_ADDR struct_addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int word_size = gdbarch_ptr_bit (gdbarch) / 8;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   int i;
@@ -2083,11 +2083,14 @@ s390_return_value (struct gdbarch *gdbarch, struct value *function,
       rvc = RETURN_VALUE_STRUCT_CONVENTION;
       break;
     case TYPE_CODE_ARRAY:
-      rvc = (gdbarch_tdep (gdbarch)->vector_abi == S390_VECTOR_ABI_128
-	     && TYPE_LENGTH (type) <= 16 && type->is_vector ())
-	? RETURN_VALUE_REGISTER_CONVENTION
-	: RETURN_VALUE_STRUCT_CONVENTION;
-      break;
+      {
+	s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+	rvc = (tdep->vector_abi == S390_VECTOR_ABI_128
+	       && TYPE_LENGTH (type) <= 16 && type->is_vector ())
+	  ? RETURN_VALUE_REGISTER_CONVENTION
+	  : RETURN_VALUE_STRUCT_CONVENTION;
+	break;
+      }
     default:
       rvc = TYPE_LENGTH (type) <= 8
 	? RETURN_VALUE_REGISTER_CONVENTION
@@ -2165,7 +2168,7 @@ s390_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 static CORE_ADDR
 s390_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST pc;
   pc = frame_unwind_register_unsigned (next_frame, tdep->pc_regnum);
   return gdbarch_addr_bits_remove (gdbarch, pc);
@@ -2187,7 +2190,7 @@ static struct value *
 s390_unwind_pseudo_register (struct frame_info *this_frame, int regnum)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct type *type = register_type (gdbarch, regnum);
 
   /* Unwind PC via PSW address.  */
@@ -2772,7 +2775,7 @@ static CORE_ADDR
 s390_record_address_mask (struct gdbarch *gdbarch, struct regcache *regcache,
 			  CORE_ADDR val)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   ULONGEST pswm, pswa;
   int am;
   if (tdep->abi == ABI_LINUX_S390)
@@ -2839,7 +2842,7 @@ s390_record_calc_disp_vsce (struct gdbarch *gdbarch, struct regcache *regcache,
 			    uint8_t vx, uint8_t el, uint8_t es, uint16_t bd,
 			    int8_t dh, CORE_ADDR *res)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   ULONGEST x;
   gdb_byte buf[16];
@@ -2882,7 +2885,7 @@ static int s390_popcnt (unsigned int x) {
 static int
 s390_record_gpr_g (struct gdbarch *gdbarch, struct regcache *regcache, int i)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (record_full_arch_list_add_reg (regcache, S390_R0_REGNUM + i))
     return -1;
   if (tdep->abi == ABI_LINUX_S390)
@@ -2896,7 +2899,7 @@ s390_record_gpr_g (struct gdbarch *gdbarch, struct regcache *regcache, int i)
 static int
 s390_record_gpr_h (struct gdbarch *gdbarch, struct regcache *regcache, int i)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   if (tdep->abi == ABI_LINUX_S390)
     {
       if (record_full_arch_list_add_reg (regcache, S390_R0_UPPER_REGNUM + i))
@@ -2936,7 +2939,7 @@ static int
 s390_process_record (struct gdbarch *gdbarch, struct regcache *regcache,
 		     CORE_ADDR addr)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  s390_gdbarch_tdep *tdep = (s390_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   uint16_t insn[3] = {0};
   /* Instruction as bytes.  */
   uint8_t ibyte[6];
@@ -6831,7 +6834,7 @@ while (0)
    tdesc.  */
 
 static bool
-s390_tdesc_valid (struct gdbarch_tdep *tdep,
+s390_tdesc_valid (s390_gdbarch_tdep *tdep,
 		  struct tdesc_arch_data *tdesc_data)
 {
   static const char *const psw[] = {
@@ -6983,10 +6986,10 @@ s390_tdesc_valid (struct gdbarch_tdep *tdep,
 /* Allocate and initialize new gdbarch_tdep.  Caller is responsible to free
    memory after use.  */
 
-static struct gdbarch_tdep *
+static s390_gdbarch_tdep *
 s390_gdbarch_tdep_alloc ()
 {
-  struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
+  s390_gdbarch_tdep *tdep = new s390_gdbarch_tdep;
 
   tdep->tdesc = NULL;
 
@@ -7023,7 +7026,7 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   static const char *const stap_register_indirection_suffixes[] = { ")",
 								    NULL };
 
-  struct gdbarch_tdep *tdep = s390_gdbarch_tdep_alloc ();
+  s390_gdbarch_tdep *tdep = s390_gdbarch_tdep_alloc ();
   struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
   tdesc_arch_data_up tdesc_data = tdesc_data_alloc ();
   info.tdesc_data = tdesc_data.get ();
@@ -7153,7 +7156,7 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* Check any target description for validity.  */
   if (!s390_tdesc_valid (tdep, tdesc_data.get ()))
     {
-      xfree (tdep);
+      delete tdep;
       gdbarch_free (gdbarch);
       return NULL;
     }
@@ -7174,16 +7177,19 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      struct gdbarch_tdep *tmp = gdbarch_tdep (arches->gdbarch);
+      s390_gdbarch_tdep *tmp
+	= (s390_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
       if (!tmp)
 	continue;
+
       /* A program can 'choose' not to use the vector registers when they
 	 are present.  Leading to the same tdesc but different tdep and
 	 thereby a different gdbarch.  */
       if (tmp->vector_abi != tdep->vector_abi)
 	continue;
 
-      xfree (tdep);
+      delete tdep;
       gdbarch_free (gdbarch);
       return arches->gdbarch;
     }
diff --git a/gdb/s390-tdep.h b/gdb/s390-tdep.h
index 8c9d75a..191977e 100644
--- a/gdb/s390-tdep.h
+++ b/gdb/s390-tdep.h
@@ -37,32 +37,33 @@ enum s390_vector_abi_kind
 
 /* The tdep structure.  */
 
-struct gdbarch_tdep
+struct s390_gdbarch_tdep : gdbarch_tdep
 {
   /* Target description.  */
-  const struct target_desc *tdesc;
+  const struct target_desc *tdesc = nullptr;
 
   /* ABI version.  */
-  enum s390_abi_kind abi;
+  enum s390_abi_kind abi {};
 
   /* Vector ABI.  */
-  enum s390_vector_abi_kind vector_abi;
+  enum s390_vector_abi_kind vector_abi {};
 
   /* Pseudo register numbers.  */
-  int gpr_full_regnum;
-  int pc_regnum;
-  int cc_regnum;
-  int v0_full_regnum;
+  int gpr_full_regnum = 0;
+  int pc_regnum = 0;
+  int cc_regnum = 0;
+  int v0_full_regnum = 0;
 
-  bool have_upper;
-  bool have_linux_v1;
-  bool have_linux_v2;
-  bool have_tdb;
-  bool have_vx;
-  bool have_gs;
+  bool have_upper = 0;
+  bool have_linux_v1 = 0;
+  bool have_linux_v2 = 0;
+  bool have_tdb = 0;
+  bool have_vx = 0;
+  bool have_gs = 0;
 
   /* Hook to record OS specific systemcall.  */
-  int (*s390_syscall_record) (struct regcache *regcache, LONGEST svc_number);
+  int (*s390_syscall_record) (struct regcache *regcache, LONGEST svc_number)
+    = nullptr;
 };
 
 /* Decoding S/390 instructions.  */
diff --git a/gdb/sh-linux-tdep.c b/gdb/sh-linux-tdep.c
index 8315d46..9d4bebb 100644
--- a/gdb/sh-linux-tdep.c
+++ b/gdb/sh-linux-tdep.c
@@ -195,7 +195,7 @@ sh_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 					     svr4_fetch_objfile_link_map);
 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sh_gdbarch_tdep *tdep = (sh_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Remember regset characteristics.  The sizes should match
      elf_gregset_t and elf_fpregset_t from Linux.  */
diff --git a/gdb/sh-netbsd-tdep.c b/gdb/sh-netbsd-tdep.c
index 0401eee..ddb2c7e 100644
--- a/gdb/sh-netbsd-tdep.c
+++ b/gdb/sh-netbsd-tdep.c
@@ -63,7 +63,7 @@ static void
 shnbsd_init_abi (struct gdbarch_info info,
 		  struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sh_gdbarch_tdep *tdep = (sh_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   nbsd_init_abi (info, gdbarch);
 
   tdep->core_gregmap = (struct sh_corefile_regmap *)regmap;
diff --git a/gdb/sh-tdep.c b/gdb/sh-tdep.c
index f78eb2d..4346e78 100644
--- a/gdb/sh-tdep.c
+++ b/gdb/sh-tdep.c
@@ -1554,7 +1554,7 @@ sh_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 static struct type *
 sh_littlebyte_bigword_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sh_gdbarch_tdep *tdep = (sh_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->sh_littlebyte_bigword_type == NULL)
     tdep->sh_littlebyte_bigword_type
@@ -2146,7 +2146,7 @@ sh_corefile_supply_regset (const struct regset *regset,
 			   int regnum, const void *regs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sh_gdbarch_tdep *tdep = (sh_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const struct sh_corefile_regmap *regmap = (regset == &sh_corefile_gregset
 					     ? tdep->core_gregmap
 					     : tdep->core_fpregmap);
@@ -2172,7 +2172,7 @@ sh_corefile_collect_regset (const struct regset *regset,
 			    int regnum, void *regs, size_t len)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sh_gdbarch_tdep *tdep = (sh_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   const struct sh_corefile_regmap *regmap = (regset == &sh_corefile_gregset
 					     ? tdep->core_gregmap
 					     : tdep->core_fpregmap);
@@ -2210,7 +2210,7 @@ sh_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				 void *cb_data,
 				 const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sh_gdbarch_tdep *tdep = (sh_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->core_gregmap != NULL)
     cb (".reg", tdep->sizeof_gregset, tdep->sizeof_gregset,
@@ -2237,7 +2237,6 @@ static struct gdbarch *
 sh_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
 
   /* If there is already a candidate, use it.  */
   arches = gdbarch_list_lookup_by_info (arches, &info);
@@ -2246,7 +2245,7 @@ sh_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* None found, create a new architecture from the information
      provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  sh_gdbarch_tdep *tdep = new sh_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   set_gdbarch_short_bit (gdbarch, 2 * TARGET_CHAR_BIT);
diff --git a/gdb/sh-tdep.h b/gdb/sh-tdep.h
index 737b6dc..fce3f71 100644
--- a/gdb/sh-tdep.h
+++ b/gdb/sh-tdep.h
@@ -19,6 +19,8 @@
 #ifndef SH_TDEP_H
 #define SH_TDEP_H
 
+#include "gdbarch.h"
+
 /* Contributed by Steve Chamberlain sac@cygnus.com.  */
 
 /* Registers for all SH variants.  Used also by sh3-rom.c.  */
@@ -89,20 +91,20 @@ struct sh_corefile_regmap
   unsigned int offset;
 };
 
-struct gdbarch_tdep
+struct sh_gdbarch_tdep : gdbarch_tdep
 {
   /* Non-NULL when debugging from a core file.  Provides the offset
      where each general-purpose register is stored inside the associated
      core file section.  */
-  struct sh_corefile_regmap *core_gregmap;
-  int sizeof_gregset;
+  struct sh_corefile_regmap *core_gregmap = nullptr;
+  int sizeof_gregset = 0;
   /* Non-NULL when debugging from a core file and when FP registers are
      available.  Provides the offset where each FP register is stored
      inside the associated core file section.  */
-  struct sh_corefile_regmap *core_fpregmap;
-  int sizeof_fpregset;
+  struct sh_corefile_regmap *core_fpregmap = nullptr;
+  int sizeof_fpregset = 0;
   /* ISA-specific data types.  */
-  struct type *sh_littlebyte_bigword_type;
+  struct type *sh_littlebyte_bigword_type = nullptr;
 };
 
 extern const struct regset sh_corefile_gregset;
diff --git a/gdb/sparc-linux-tdep.c b/gdb/sparc-linux-tdep.c
index 4ad77e2..9c46919 100644
--- a/gdb/sparc-linux-tdep.c
+++ b/gdb/sparc-linux-tdep.c
@@ -253,7 +253,8 @@ sparc32_linux_collect_core_fpregset (const struct regset *regset,
 static void
 sparc_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (arch);
   ULONGEST psr;
 
   regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc);
@@ -420,7 +421,7 @@ static const struct regset sparc32_linux_fpregset =
 static void
 sparc32_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/sparc-netbsd-tdep.c b/gdb/sparc-netbsd-tdep.c
index e34405c..e600447 100644
--- a/gdb/sparc-netbsd-tdep.c
+++ b/gdb/sparc-netbsd-tdep.c
@@ -295,7 +295,7 @@ static const struct regset sparc32nbsd_fpregset =
 void
 sparc32nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   nbsd_init_abi (info, gdbarch);
 
diff --git a/gdb/sparc-sol2-tdep.c b/gdb/sparc-sol2-tdep.c
index f214449..94e8a12 100644
--- a/gdb/sparc-sol2-tdep.c
+++ b/gdb/sparc-sol2-tdep.c
@@ -196,7 +196,7 @@ static const struct frame_unwind sparc32_sol2_sigtramp_frame_unwind =
 static void
 sparc32_sol2_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->gregset = &sparc32_sol2_gregset;
   tdep->sizeof_gregset = 152;
diff --git a/gdb/sparc-tdep.c b/gdb/sparc-tdep.c
index 7302929..31916b6 100644
--- a/gdb/sparc-tdep.c
+++ b/gdb/sparc-tdep.c
@@ -429,7 +429,7 @@ sparc32_register_name (struct gdbarch *gdbarch, int regnum)
 static struct type *
 sparc_psr_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->sparc_psr_type)
     {
@@ -451,7 +451,7 @@ sparc_psr_type (struct gdbarch *gdbarch)
 static struct type *
 sparc_fsr_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->sparc_fsr_type)
     {
@@ -992,7 +992,7 @@ CORE_ADDR
 sparc_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR pc,
 			CORE_ADDR current_pc, struct sparc_frame_cache *cache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   unsigned long insn;
   int offset = 0;
   int dest = -1;
@@ -1684,8 +1684,9 @@ sparc_analyze_control_transfer (struct regcache *regcache,
       struct frame_info *frame = get_current_frame ();
 
       /* Trap instruction (TRAP).  */
-      return gdbarch_tdep (regcache->arch ())->step_trap (frame,
-								     insn);
+      gdbarch *arch = regcache->arch ();
+      sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (arch);
+      return tdep->step_trap (frame, insn);
     }
 
   /* FIXME: Handle DONE and RETRY instructions.  */
@@ -1735,7 +1736,7 @@ static std::vector<CORE_ADDR>
 sparc_software_single_step (struct regcache *regcache)
 {
   struct gdbarch *arch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (arch);
   CORE_ADDR npc, nnpc;
 
   CORE_ADDR pc, orig_npc;
@@ -1764,7 +1765,8 @@ sparc_software_single_step (struct regcache *regcache)
 static void
 sparc_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (arch);
 
   regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc);
   regcache_cooked_write_unsigned (regcache, tdep->npc_regnum, pc + 4);
@@ -1779,7 +1781,7 @@ sparc_iterate_over_regset_sections (struct gdbarch *gdbarch,
 				    void *cb_data,
 				    const struct regcache *regcache)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   cb (".reg", tdep->sizeof_gregset, tdep->sizeof_gregset, tdep->gregset, NULL,
       cb_data);
@@ -1814,7 +1816,6 @@ validate_tdesc_registers (const struct target_desc *tdesc,
 static struct gdbarch *
 sparc32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   const struct target_desc *tdesc = info.target_desc;
   struct gdbarch *gdbarch;
   int valid_p = 1;
@@ -1825,7 +1826,7 @@ sparc32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     return arches->gdbarch;
 
   /* Allocate space for the new architecture.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  sparc_gdbarch_tdep *tdep = new sparc_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   tdep->pc_regnum = SPARC32_PC_REGNUM;
diff --git a/gdb/sparc-tdep.h b/gdb/sparc-tdep.h
index c0cfd09..ceedb2c 100644
--- a/gdb/sparc-tdep.h
+++ b/gdb/sparc-tdep.h
@@ -20,6 +20,8 @@
 #ifndef SPARC_TDEP_H
 #define SPARC_TDEP_H 1
 
+#include "gdbarch.h"
+
 #define SPARC_CORE_REGISTERS                      \
   "g0", "g1", "g2", "g3", "g4", "g5", "g6", "g7", \
   "o0", "o1", "o2", "o3", "o4", "o5", "sp", "o7", \
@@ -55,43 +57,44 @@ struct sparc_fpregmap
 
 /* SPARC architecture-specific information.  */
 
-struct gdbarch_tdep
+struct sparc_gdbarch_tdep : gdbarch_tdep
 {
   /* Register numbers for the PN and nPC registers.  The definitions
      for (64-bit) UltraSPARC differ from the (32-bit) SPARC
      definitions.  */
-  int pc_regnum;
-  int npc_regnum;
+  int pc_regnum = 0;
+  int npc_regnum = 0;
 
   /* Register names specific for architecture (sparc32 vs. sparc64) */
-  const char * const *fpu_register_names;
-  size_t fpu_registers_num;
-  const char * const *cp0_register_names;
-  size_t cp0_registers_num;
+  const char * const *fpu_register_names = nullptr;
+  size_t fpu_registers_num = 0;
+  const char * const *cp0_register_names = nullptr;
+  size_t cp0_registers_num = 0;
 
   /* Register sets.  */
-  const struct regset *gregset;
-  size_t sizeof_gregset;
-  const struct regset *fpregset;
-  size_t sizeof_fpregset;
+  const struct regset *gregset = nullptr;
+  size_t sizeof_gregset = 0;
+  const struct regset *fpregset = nullptr;
+  size_t sizeof_fpregset = 0;
 
   /* Offset of saved PC in jmp_buf.  */
-  int jb_pc_offset;
+  int jb_pc_offset = 0;
 
   /* Size of an Procedure Linkage Table (PLT) entry, 0 if we shouldn't
      treat the PLT special when doing prologue analysis.  */
-  size_t plt_entry_size;
+  size_t plt_entry_size = 0;
 
   /* Alternative location for trap return.  Used for single-stepping.  */
-  CORE_ADDR (*step_trap) (struct frame_info *frame, unsigned long insn);
+  CORE_ADDR (*step_trap) (struct frame_info *frame, unsigned long insn)
+    = nullptr;
 
   /* ISA-specific data types.  */
-  struct type *sparc_psr_type;
-  struct type *sparc_fsr_type;
-  struct type *sparc64_ccr_type;
-  struct type *sparc64_pstate_type;
-  struct type *sparc64_fsr_type;
-  struct type *sparc64_fprs_type;
+  struct type *sparc_psr_type = nullptr;
+  struct type *sparc_fsr_type = nullptr;
+  struct type *sparc64_ccr_type = nullptr;
+  struct type *sparc64_pstate_type = nullptr;
+  struct type *sparc64_fsr_type = nullptr;
+  struct type *sparc64_fprs_type = nullptr;
 };
 
 /* Register numbers of various important registers.  */
diff --git a/gdb/sparc64-fbsd-tdep.c b/gdb/sparc64-fbsd-tdep.c
index 6dad813..d52162a 100644
--- a/gdb/sparc64-fbsd-tdep.c
+++ b/gdb/sparc64-fbsd-tdep.c
@@ -222,7 +222,7 @@ static const struct regset sparc64fbsd_fpregset =
 static void
 sparc64fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Generic FreeBSD support. */
   fbsd_init_abi (info, gdbarch);
diff --git a/gdb/sparc64-linux-tdep.c b/gdb/sparc64-linux-tdep.c
index e63fa87..5b9cc90 100644
--- a/gdb/sparc64-linux-tdep.c
+++ b/gdb/sparc64-linux-tdep.c
@@ -261,7 +261,8 @@ sparc64_linux_collect_core_fpregset (const struct regset *regset,
 static void
 sparc64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
+  gdbarch *arch = regcache->arch ();
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (arch);
   ULONGEST state;
 
   regcache_cooked_write_unsigned (regcache, tdep->pc_regnum, pc);
@@ -363,7 +364,7 @@ static const struct regset sparc64_linux_fpregset =
 static void
 sparc64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/sparc64-netbsd-tdep.c b/gdb/sparc64-netbsd-tdep.c
index 0438093..81e3763 100644
--- a/gdb/sparc64-netbsd-tdep.c
+++ b/gdb/sparc64-netbsd-tdep.c
@@ -248,7 +248,7 @@ static const struct regset sparc64nbsd_fpregset =
 static void
 sparc64nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   nbsd_init_abi (info, gdbarch);
 
diff --git a/gdb/sparc64-obsd-tdep.c b/gdb/sparc64-obsd-tdep.c
index 033779e..0931b23 100644
--- a/gdb/sparc64-obsd-tdep.c
+++ b/gdb/sparc64-obsd-tdep.c
@@ -423,7 +423,7 @@ static const struct regset sparc64obsd_fpregset =
 static void
 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->gregset = &sparc64obsd_gregset;
   tdep->sizeof_gregset = 288;
diff --git a/gdb/sparc64-sol2-tdep.c b/gdb/sparc64-sol2-tdep.c
index 6aea8bd..6c1fe19 100644
--- a/gdb/sparc64-sol2-tdep.c
+++ b/gdb/sparc64-sol2-tdep.c
@@ -199,7 +199,7 @@ static const struct frame_unwind sparc64_sol2_sigtramp_frame_unwind =
 static void
 sparc64_sol2_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->gregset = &sparc64_sol2_gregset;
   tdep->sizeof_gregset = 304;
diff --git a/gdb/sparc64-tdep.c b/gdb/sparc64-tdep.c
index c0d3159..cb69830 100644
--- a/gdb/sparc64-tdep.c
+++ b/gdb/sparc64-tdep.c
@@ -648,7 +648,7 @@ sparc64_structure_or_union_p (const struct type *type)
 static struct type *
 sparc64_pstate_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->sparc64_pstate_type)
     {
@@ -675,7 +675,7 @@ sparc64_pstate_type (struct gdbarch *gdbarch)
 static struct type *
 sparc64_ccr_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->sparc64_ccr_type == NULL)
     {
@@ -700,7 +700,7 @@ sparc64_ccr_type (struct gdbarch *gdbarch)
 static struct type *
 sparc64_fsr_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->sparc64_fsr_type)
     {
@@ -733,7 +733,7 @@ sparc64_fsr_type (struct gdbarch *gdbarch)
 static struct type *
 sparc64_fprs_type (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (!tdep->sparc64_fprs_type)
     {
@@ -1806,7 +1806,7 @@ sparc64_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR addr)
 void
 sparc64_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  sparc_gdbarch_tdep *tdep = (sparc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   tdep->pc_regnum = SPARC64_PC_REGNUM;
   tdep->npc_regnum = SPARC64_NPC_REGNUM;
diff --git a/gdb/tic6x-linux-tdep.c b/gdb/tic6x-linux-tdep.c
index 4e165ec..ff5fec8 100644
--- a/gdb/tic6x-linux-tdep.c
+++ b/gdb/tic6x-linux-tdep.c
@@ -45,7 +45,7 @@ static const gdb_byte tic6x_bkpt_bnop_le[] = { 0x22, 0xa1, 0x00, 0x00 };
 static unsigned int
 tic6x_register_sigcontext_offset (unsigned int regnum, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  tic6x_gdbarch_tdep *tdep = (tic6x_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (regnum == TIC6X_A4_REGNUM || regnum == TIC6X_A4_REGNUM + 2
       || regnum == TIC6X_A4_REGNUM + 4)
@@ -92,7 +92,7 @@ tic6x_linux_rt_sigreturn_init (const struct tramp_frame *self,
 		    + TIC6X_SIGINFO_SIZE
 		    + 4 + 4 /* uc_flags and *uc_link in struct ucontext.  */
 		    + TIC6X_STACK_T_SIZE);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  tic6x_gdbarch_tdep *tdep = (tic6x_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   unsigned int reg_offset;
   unsigned int i;
 
@@ -165,7 +165,7 @@ extern struct target_so_ops dsbt_so_ops;
 static void
 tic6x_uclinux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  tic6x_gdbarch_tdep *tdep = (tic6x_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   linux_init_abi (info, gdbarch, 0);
 
diff --git a/gdb/tic6x-tdep.c b/gdb/tic6x-tdep.c
index afa034c..7b1d83b 100644
--- a/gdb/tic6x-tdep.c
+++ b/gdb/tic6x-tdep.c
@@ -325,7 +325,7 @@ tic6x_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 static const gdb_byte *
 tic6x_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  tic6x_gdbarch_tdep *tdep = (tic6x_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   *size = kind;
 
@@ -598,7 +598,8 @@ tic6x_get_next_pc (struct regcache *regcache, CORE_ADDR pc)
 
       if (inst == TIC6X_INST_SWE)
 	{
-	  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+	  tic6x_gdbarch_tdep *tdep
+	    = (tic6x_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
 	  if (tdep->syscall_next_pc != NULL)
 	    return tdep->syscall_next_pc (get_current_frame ());
@@ -1141,7 +1142,6 @@ static struct gdbarch *
 tic6x_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
   int has_gp = 0;
@@ -1216,7 +1216,8 @@ tic6x_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      tdep = gdbarch_tdep (arches->gdbarch);
+      tic6x_gdbarch_tdep *tdep
+	= (tic6x_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
 
       if (has_gp != tdep->has_gp)
 	continue;
@@ -1225,7 +1226,7 @@ tic6x_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 	return arches->gdbarch;
     }
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  tic6x_gdbarch_tdep *tdep = new tic6x_gdbarch_tdep;
 
   tdep->has_gp = has_gp;
   gdbarch = gdbarch_alloc (&info, tdep);
diff --git a/gdb/tic6x-tdep.h b/gdb/tic6x-tdep.h
index 7d5587a..bb79a0d 100644
--- a/gdb/tic6x-tdep.h
+++ b/gdb/tic6x-tdep.h
@@ -20,6 +20,8 @@
 #ifndef TIC6X_TDEP_H
 #define TIC6X_TDEP_H
 
+#include "gdbarch.h"
+
 enum
 {
   TIC6X_A4_REGNUM = 4,
@@ -44,15 +46,15 @@ extern const gdb_byte tic6x_bkpt_illegal_opcode_be[];
 extern const gdb_byte tic6x_bkpt_illegal_opcode_le[];
 
 /* Target-dependent structure in gdbarch.  */
-struct gdbarch_tdep
+struct tic6x_gdbarch_tdep : gdbarch_tdep
 {
   /* Return the expected next PC if FRAME is stopped at a syscall
      instruction.  */
-  CORE_ADDR (*syscall_next_pc) (struct frame_info *frame);
+  CORE_ADDR (*syscall_next_pc) (struct frame_info *frame) = nullptr;
 
-  const gdb_byte *breakpoint; /* Breakpoint instruction.  */
+  const gdb_byte *breakpoint = nullptr; /* Breakpoint instruction.  */
 
-  int has_gp; /* Has general purpose registers A16 - A31 and B16 - B31.  */
+  int has_gp = 0; /* Has general purpose registers A16 - A31 and B16 - B31.  */
 };
 
 #endif /* TIC6X_TDEP_H */
diff --git a/gdb/v850-tdep.c b/gdb/v850-tdep.c
index f829f4d..70f6d42 100644
--- a/gdb/v850-tdep.c
+++ b/gdb/v850-tdep.c
@@ -264,15 +264,15 @@ enum v850_abi
 
 /* Architecture specific data.  */
 
-struct gdbarch_tdep
+struct v850_gdbarch_tdep : gdbarch_tdep
 {
   /* Fields from the ELF header.  */
-  int e_flags;
-  int e_machine;
+  int e_flags = 0;
+  int e_machine = 0;
 
   /* Which ABI are we using?  */
-  enum v850_abi abi;
-  int eight_byte_align;
+  enum v850_abi abi {};
+  int eight_byte_align = 0;
 };
 
 struct v850_frame_cache
@@ -510,8 +510,9 @@ v850_use_struct_convention (struct gdbarch *gdbarch, struct type *type)
 {
   int i;
   struct type *fld_type, *tgt_type;
+  v850_gdbarch_tdep *tdep = (v850_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
-  if (gdbarch_tdep (gdbarch)->abi == V850_ABI_RH850)
+  if (tdep->abi == V850_ABI_RH850)
     {
       if (v850_type_is_scalar (type) && TYPE_LENGTH(type) <= 8)
 	return 0;
@@ -1021,8 +1022,9 @@ v850_push_dummy_call (struct gdbarch *gdbarch,
   int argnum;
   int arg_space = 0;
   int stack_offset;
+  v850_gdbarch_tdep *tdep = (v850_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
-  if (gdbarch_tdep (gdbarch)->abi == V850_ABI_RH850)
+  if (tdep->abi == V850_ABI_RH850)
     stack_offset = 0;
   else
     {
@@ -1054,7 +1056,7 @@ v850_push_dummy_call (struct gdbarch *gdbarch,
       gdb_byte valbuf[v850_reg_size];
 
       if (!v850_type_is_scalar (value_type (*args))
-	 && gdbarch_tdep (gdbarch)->abi == V850_ABI_GCC
+	  && tdep->abi == V850_ABI_GCC
 	  && TYPE_LENGTH (value_type (*args)) > E_MAX_RETTYPE_SIZE_IN_REGS)
 	{
 	  store_unsigned_integer (valbuf, 4, byte_order,
@@ -1068,7 +1070,7 @@ v850_push_dummy_call (struct gdbarch *gdbarch,
 	  val = (gdb_byte *) value_contents (*args).data ();
 	}
 
-      if (gdbarch_tdep (gdbarch)->eight_byte_align
+      if (tdep->eight_byte_align
 	  && v850_eight_byte_align_p (value_type (*args)))
 	{
 	  if (argreg <= E_ARGLAST_REGNUM && (argreg & 1))
@@ -1348,7 +1350,6 @@ static struct gdbarch *
 v850_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int e_flags, e_machine;
 
   /* Extract the elf_flags if available.  */
@@ -1371,13 +1372,16 @@ v850_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        arches != NULL;
        arches = gdbarch_list_lookup_by_info (arches->next, &info))
     {
-      if (gdbarch_tdep (arches->gdbarch)->e_flags != e_flags
-	  || gdbarch_tdep (arches->gdbarch)->e_machine != e_machine)
+      v850_gdbarch_tdep *tdep
+	= (v850_gdbarch_tdep *) gdbarch_tdep (arches->gdbarch);
+
+      if (tdep->e_flags != e_flags || tdep->e_machine != e_machine)
 	continue;
 
       return arches->gdbarch;
     }
-  tdep = XCNEW (struct gdbarch_tdep);
+
+  v850_gdbarch_tdep *tdep = new v850_gdbarch_tdep;
   tdep->e_flags = e_flags;
   tdep->e_machine = e_machine;
 
diff --git a/gdb/xtensa-config.c b/gdb/xtensa-config.c
index 2c21c78..57a9ff0 100644
--- a/gdb/xtensa-config.c
+++ b/gdb/xtensa-config.c
@@ -62,7 +62,7 @@ const xtensa_mask_t xtensa_mask15 = { 1, xtensa_submask15 };
 
 
 /* Register map.  */
-xtensa_register_t rmap[] = 
+static xtensa_register_t rmap[] =
 {
   /*    idx ofs bi sz al targno  flags cp typ group name  */
   XTREG(  0,  0,32, 4, 4,0x0020,0x0006,-2, 9,0x0100,pc,          0,0,0,0,0,0)
@@ -213,9 +213,4 @@ xtensa_register_t rmap[] =
   XTREG_END
 };
 
-
-
-#ifdef XTENSA_CONFIG_INSTANTIATE
-XTENSA_CONFIG_INSTANTIATE(rmap,0)
-#endif
-
+xtensa_gdbarch_tdep xtensa_tdep (rmap);
diff --git a/gdb/xtensa-linux-tdep.c b/gdb/xtensa-linux-tdep.c
index c9e2519..b24ebc5 100644
--- a/gdb/xtensa-linux-tdep.c
+++ b/gdb/xtensa-linux-tdep.c
@@ -99,7 +99,7 @@ xtensa_linux_gdb_signal_to_target (struct gdbarch *gdbarch,
 static void
 xtensa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (tdep->num_nopriv_regs < tdep->num_regs)
     {
diff --git a/gdb/xtensa-tdep.c b/gdb/xtensa-tdep.c
index 42bff4c..f09d233 100644
--- a/gdb/xtensa-tdep.c
+++ b/gdb/xtensa-tdep.c
@@ -86,13 +86,13 @@ static unsigned int xtensa_debug_level = 0;
 #define TX_PS			0x20
 
 /* ABI-independent macros.  */
-#define ARG_NOF(gdbarch) \
-  (gdbarch_tdep (gdbarch)->call_abi \
+#define ARG_NOF(tdep) \
+  (tdep->call_abi \
    == CallAbiCall0Only ? C0_NARGS : (ARGS_NUM_REGS))
-#define ARG_1ST(gdbarch) \
-  (gdbarch_tdep (gdbarch)->call_abi  == CallAbiCall0Only \
-   ? (gdbarch_tdep (gdbarch)->a0_base + C0_ARGS) \
-   : (gdbarch_tdep (gdbarch)->a0_base + 6))
+#define ARG_1ST(tdep) \
+  (tdep->call_abi  == CallAbiCall0Only \
+   ? (tdep->a0_base + C0_ARGS) \
+   : (tdep->a0_base + 6))
 
 /* XTENSA_IS_ENTRY tests whether the first byte of an instruction
    indicates that the instruction is an ENTRY instruction.  */
@@ -116,8 +116,10 @@ static unsigned int xtensa_debug_level = 0;
 static int
 windowing_enabled (struct gdbarch *gdbarch, unsigned int ps)
 {
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   /* If we know CALL0 ABI is set explicitly,  say it is Call0.  */
-  if (gdbarch_tdep (gdbarch)->call_abi == CallAbiCall0Only)
+  if (tdep->call_abi == CallAbiCall0Only)
     return 0;
 
   return ((ps & PS_EXC) == 0 && (ps & PS_WOE) != 0);
@@ -128,7 +130,7 @@ windowing_enabled (struct gdbarch *gdbarch, unsigned int ps)
 static int
 arreg_number (struct gdbarch *gdbarch, int a_regnum, ULONGEST wb)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int arreg;
 
   arreg = a_regnum - tdep->a0_base;
@@ -143,7 +145,7 @@ arreg_number (struct gdbarch *gdbarch, int a_regnum, ULONGEST wb)
 static int
 areg_number (struct gdbarch *gdbarch, int ar_regnum, unsigned int wb)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int areg;
 
   areg = ar_regnum - tdep->ar_base;
@@ -224,10 +226,10 @@ static int
 xtensa_find_register_by_name (struct gdbarch *gdbarch, const char *name)
 {
   int i;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   for (i = 0; i < gdbarch_num_cooked_regs (gdbarch); i++)
-
-    if (strcasecmp (gdbarch_tdep (gdbarch)->regmap[i].name, name) == 0)
+    if (strcasecmp (tdep->regmap[i].name, name) == 0)
       return i;
 
   return -1;
@@ -237,9 +239,11 @@ xtensa_find_register_by_name (struct gdbarch *gdbarch, const char *name)
 static const char *
 xtensa_register_name (struct gdbarch *gdbarch, int regnum)
 {
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
   /* Return the name stored in the register map.  */
   if (regnum >= 0 && regnum < gdbarch_num_cooked_regs (gdbarch))
-    return gdbarch_tdep (gdbarch)->regmap[regnum].name;
+    return tdep->regmap[regnum].name;
 
   internal_error (__FILE__, __LINE__, _("invalid register %d"), regnum);
   return 0;
@@ -250,7 +254,7 @@ xtensa_register_name (struct gdbarch *gdbarch, int regnum)
 static struct type *
 xtensa_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Return signed integer for ARx and Ax registers.  */
   if ((regnum >= tdep->ar_base
@@ -335,12 +339,13 @@ static int
 xtensa_reg_to_regnum (struct gdbarch *gdbarch, int regnum)
 {
   int i;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (regnum >= 0 && regnum < 16)
-    return gdbarch_tdep (gdbarch)->a0_base + regnum;
+    return tdep->a0_base + regnum;
 
   for (i = 0; i < gdbarch_num_cooked_regs (gdbarch); i++)
-    if (regnum == gdbarch_tdep (gdbarch)->regmap[i].target_number)
+    if (regnum == tdep->regmap[i].target_number)
       return i;
 
   return -1;
@@ -537,16 +542,17 @@ xtensa_pseudo_register_read (struct gdbarch *gdbarch,
 {
   DEBUGTRACE ("xtensa_pseudo_register_read (... regnum = %d (%s) ...)\n",
 	      regnum, xtensa_register_name (gdbarch, regnum));
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Read aliases a0..a15, if this is a Windowed ABI.  */
-  if (gdbarch_tdep (gdbarch)->isa_use_windowed_registers
-      && (regnum >= gdbarch_tdep (gdbarch)->a0_base)
-      && (regnum <= gdbarch_tdep (gdbarch)->a0_base + 15))
+  if (tdep->isa_use_windowed_registers
+      && (regnum >= tdep->a0_base)
+      && (regnum <= tdep->a0_base + 15))
     {
       ULONGEST value;
       enum register_status status;
 
-      status = regcache->raw_read (gdbarch_tdep (gdbarch)->wb_regnum,
+      status = regcache->raw_read (tdep->wb_regnum,
 				   &value);
       if (status != REG_VALID)
 	return status;
@@ -560,8 +566,8 @@ xtensa_pseudo_register_read (struct gdbarch *gdbarch,
   /* We have to find out how to deal with priveleged registers.
      Let's treat them as pseudo-registers, but we cannot read/write them.  */
      
-  else if (gdbarch_tdep (gdbarch)->call_abi == CallAbiCall0Only
-	   || regnum < gdbarch_tdep (gdbarch)->a0_base)
+  else if (tdep->call_abi == CallAbiCall0Only
+	   || regnum < tdep->a0_base)
     {
       buffer[0] = (gdb_byte)0;
       buffer[1] = (gdb_byte)0;
@@ -572,9 +578,9 @@ xtensa_pseudo_register_read (struct gdbarch *gdbarch,
   /* Pseudo registers.  */
   else if (regnum >= 0 && regnum < gdbarch_num_cooked_regs (gdbarch))
     {
-      xtensa_register_t *reg = &gdbarch_tdep (gdbarch)->regmap[regnum];
+      xtensa_register_t *reg = &tdep->regmap[regnum];
       xtensa_register_type_t type = reg->type;
-      int flags = gdbarch_tdep (gdbarch)->target_flags;
+      int flags = tdep->target_flags;
 
       /* We cannot read Unknown or Unmapped registers.  */
       if (type == xtRegisterTypeUnmapped || type == xtRegisterTypeUnknown)
@@ -628,15 +634,16 @@ xtensa_pseudo_register_write (struct gdbarch *gdbarch,
 {
   DEBUGTRACE ("xtensa_pseudo_register_write (... regnum = %d (%s) ...)\n",
 	      regnum, xtensa_register_name (gdbarch, regnum));
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Renumber register, if aliases a0..a15 on Windowed ABI.  */
-  if (gdbarch_tdep (gdbarch)->isa_use_windowed_registers
-      && (regnum >= gdbarch_tdep (gdbarch)->a0_base)
-      && (regnum <= gdbarch_tdep (gdbarch)->a0_base + 15))
+  if (tdep->isa_use_windowed_registers
+      && (regnum >= tdep->a0_base)
+      && (regnum <= tdep->a0_base + 15))
     {
       ULONGEST value;
       regcache_raw_read_unsigned (regcache,
-				  gdbarch_tdep (gdbarch)->wb_regnum, &value);
+				  tdep->wb_regnum, &value);
       regnum = arreg_number (gdbarch, regnum, value);
     }
 
@@ -648,16 +655,16 @@ xtensa_pseudo_register_write (struct gdbarch *gdbarch,
   /* We have to find out how to deal with priveleged registers.
      Let's treat them as pseudo-registers, but we cannot read/write them.  */
 
-  else if (regnum < gdbarch_tdep (gdbarch)->a0_base)
+  else if (regnum < tdep->a0_base)
     {
       return;
     }
   /* Pseudo registers.  */
   else if (regnum >= 0 && regnum < gdbarch_num_cooked_regs (gdbarch))
     {
-      xtensa_register_t *reg = &gdbarch_tdep (gdbarch)->regmap[regnum];
+      xtensa_register_t *reg = &tdep->regmap[regnum];
       xtensa_register_type_t type = reg->type;
-      int flags = gdbarch_tdep (gdbarch)->target_flags;
+      int flags = tdep->target_flags;
 
       /* On most targets, we cannot write registers
 	 of type "Unknown" or "Unmapped".  */
@@ -770,7 +777,8 @@ xtensa_register_reggroup_p (struct gdbarch *gdbarch,
 			    int regnum,
 			    struct reggroup *group)
 {
-  xtensa_register_t* reg = &gdbarch_tdep (gdbarch)->regmap[regnum];
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  xtensa_register_t* reg = &tdep->regmap[regnum];
   xtensa_register_type_t type = reg->type;
   xtensa_register_group_t rg = reg->group;
   int cp_number;
@@ -823,6 +831,7 @@ xtensa_supply_gregset (const struct regset *regset,
 {
   const xtensa_elf_gregset_t *regs = (const xtensa_elf_gregset_t *) gregs;
   struct gdbarch *gdbarch = rc->arch ();
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int i;
 
   DEBUGTRACE ("xtensa_supply_gregset (..., regnum==%d, ...)\n", regnum);
@@ -831,33 +840,33 @@ xtensa_supply_gregset (const struct regset *regset,
     rc->raw_supply (gdbarch_pc_regnum (gdbarch), (char *) &regs->pc);
   if (regnum == gdbarch_ps_regnum (gdbarch) || regnum == -1)
     rc->raw_supply (gdbarch_ps_regnum (gdbarch), (char *) &regs->ps);
-  if (regnum == gdbarch_tdep (gdbarch)->wb_regnum || regnum == -1)
-    rc->raw_supply (gdbarch_tdep (gdbarch)->wb_regnum,
+  if (regnum == tdep->wb_regnum || regnum == -1)
+    rc->raw_supply (tdep->wb_regnum,
 		    (char *) &regs->windowbase);
-  if (regnum == gdbarch_tdep (gdbarch)->ws_regnum || regnum == -1)
-    rc->raw_supply (gdbarch_tdep (gdbarch)->ws_regnum,
+  if (regnum == tdep->ws_regnum || regnum == -1)
+    rc->raw_supply (tdep->ws_regnum,
 		    (char *) &regs->windowstart);
-  if (regnum == gdbarch_tdep (gdbarch)->lbeg_regnum || regnum == -1)
-    rc->raw_supply (gdbarch_tdep (gdbarch)->lbeg_regnum,
+  if (regnum == tdep->lbeg_regnum || regnum == -1)
+    rc->raw_supply (tdep->lbeg_regnum,
 		    (char *) &regs->lbeg);
-  if (regnum == gdbarch_tdep (gdbarch)->lend_regnum || regnum == -1)
-    rc->raw_supply (gdbarch_tdep (gdbarch)->lend_regnum,
+  if (regnum == tdep->lend_regnum || regnum == -1)
+    rc->raw_supply (tdep->lend_regnum,
 		    (char *) &regs->lend);
-  if (regnum == gdbarch_tdep (gdbarch)->lcount_regnum || regnum == -1)
-    rc->raw_supply (gdbarch_tdep (gdbarch)->lcount_regnum,
+  if (regnum == tdep->lcount_regnum || regnum == -1)
+    rc->raw_supply (tdep->lcount_regnum,
 		    (char *) &regs->lcount);
-  if (regnum == gdbarch_tdep (gdbarch)->sar_regnum || regnum == -1)
-    rc->raw_supply (gdbarch_tdep (gdbarch)->sar_regnum,
+  if (regnum == tdep->sar_regnum || regnum == -1)
+    rc->raw_supply (tdep->sar_regnum,
 		    (char *) &regs->sar);
-  if (regnum >=gdbarch_tdep (gdbarch)->ar_base
-      && regnum < gdbarch_tdep (gdbarch)->ar_base
-		    + gdbarch_tdep (gdbarch)->num_aregs)
+  if (regnum >=tdep->ar_base
+      && regnum < tdep->ar_base
+		    + tdep->num_aregs)
     rc->raw_supply
-      (regnum, (char *) &regs->ar[regnum - gdbarch_tdep (gdbarch)->ar_base]);
+      (regnum, (char *) &regs->ar[regnum - tdep->ar_base]);
   else if (regnum == -1)
     {
-      for (i = 0; i < gdbarch_tdep (gdbarch)->num_aregs; ++i)
-	rc->raw_supply (gdbarch_tdep (gdbarch)->ar_base + i,
+      for (i = 0; i < tdep->num_aregs; ++i)
+	rc->raw_supply (tdep->ar_base + i,
 			(char *) &regs->ar[i]);
     }
 }
@@ -1051,12 +1060,13 @@ static struct frame_id
 xtensa_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
 {
   CORE_ADDR pc, fp;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* THIS-FRAME is a dummy frame.  Return a frame ID of that frame.  */
 
   pc = get_frame_pc (this_frame);
   fp = get_frame_register_unsigned
-	 (this_frame, gdbarch_tdep (gdbarch)->a0_base + 1);
+	 (this_frame, tdep->a0_base + 1);
 
   /* Make dummy frame ID unique by adding a constant.  */
   return frame_id_build (fp + SP_ALIGNMENT, pc);
@@ -1105,7 +1115,8 @@ xtensa_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR current_pc)
 {
 #define RETURN_FP goto done
 
-  unsigned int fp_regnum = gdbarch_tdep (gdbarch)->a0_base + 1;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  unsigned int fp_regnum = tdep->a0_base + 1;
   CORE_ADDR start_addr;
   xtensa_isa isa;
   xtensa_insnbuf ins, slot;
@@ -1182,7 +1193,7 @@ xtensa_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR current_pc)
 		    RETURN_FP;
 
 		  fp_regnum
-		    = gdbarch_tdep (gdbarch)->a0_base + register_operand;
+		    = tdep->a0_base + register_operand;
 		  RETURN_FP;
 		}
 	    }
@@ -1254,26 +1265,27 @@ xtensa_frame_cache (struct frame_info *this_frame, void **this_cache)
   if (windowed)
     {
       LONGEST op1;
+      xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
       /* Get WINDOWBASE, WINDOWSTART, and PS registers.  */
       wb = get_frame_register_unsigned (this_frame, 
-					gdbarch_tdep (gdbarch)->wb_regnum);
+					tdep->wb_regnum);
       ws = get_frame_register_unsigned (this_frame,
-					gdbarch_tdep (gdbarch)->ws_regnum);
+					tdep->ws_regnum);
 
       if (safe_read_memory_integer (pc, 1, byte_order, &op1)
 	  && XTENSA_IS_ENTRY (gdbarch, op1))
 	{
 	  int callinc = CALLINC (ps);
 	  ra = get_frame_register_unsigned
-	    (this_frame, gdbarch_tdep (gdbarch)->a0_base + callinc * 4);
+	    (this_frame, tdep->a0_base + callinc * 4);
 	  
 	  /* ENTRY hasn't been executed yet, therefore callsize is still 0.  */
 	  cache->wd.callsize = 0;
 	  cache->wd.wb = wb;
 	  cache->wd.ws = ws;
 	  cache->prev_sp = get_frame_register_unsigned
-			     (this_frame, gdbarch_tdep (gdbarch)->a0_base + 1);
+			     (this_frame, tdep->a0_base + 1);
 
 	  /* This only can be the outermost frame since we are
 	     just about to execute ENTRY.  SP hasn't been set yet.
@@ -1292,10 +1304,10 @@ xtensa_frame_cache (struct frame_info *this_frame, void **this_cache)
 	{
 	  fp_regnum = xtensa_scan_prologue (gdbarch, pc);
 	  ra = get_frame_register_unsigned (this_frame,
-					    gdbarch_tdep (gdbarch)->a0_base);
+					    tdep->a0_base);
 	  cache->wd.callsize = WINSIZE (ra);
 	  cache->wd.wb = (wb - cache->wd.callsize / 4)
-			  & (gdbarch_tdep (gdbarch)->num_aregs / 4 - 1);
+			  & (tdep->num_aregs / 4 - 1);
 	  cache->wd.ws = ws & ~(1 << wb);
 
 	  cache->pc = get_frame_func (this_frame);
@@ -1310,7 +1322,7 @@ xtensa_frame_cache (struct frame_info *this_frame, void **this_cache)
 
 	  /* Set A0...A3.  */
 	  sp = get_frame_register_unsigned
-	    (this_frame, gdbarch_tdep (gdbarch)->a0_base + 1) - 16;
+	    (this_frame, tdep->a0_base + 1) - 16;
 	  
 	  for (i = 0; i < 4; i++, sp += 4)
 	    {
@@ -1342,14 +1354,14 @@ xtensa_frame_cache (struct frame_info *this_frame, void **this_cache)
 	      /* Register window overflow already happened.
 		 We can read caller's SP from the proper spill location.  */
 	      sp = get_frame_register_unsigned
-		(this_frame, gdbarch_tdep (gdbarch)->a0_base + 1);
+		(this_frame, tdep->a0_base + 1);
 	      cache->prev_sp = read_memory_integer (sp - 12, 4, byte_order);
 	    }
 	  else
 	    {
 	      /* Read caller's frame SP directly from the previous window.  */
 	      int regnum = arreg_number
-			     (gdbarch, gdbarch_tdep (gdbarch)->a0_base + 1,
+			     (gdbarch, tdep->a0_base + 1,
 			      cache->wd.wb);
 
 	      cache->prev_sp = xtensa_read_register (regnum);
@@ -1415,6 +1427,7 @@ xtensa_frame_prev_register (struct frame_info *this_frame,
   struct xtensa_frame_cache *cache;
   ULONGEST saved_reg = 0;
   int done = 1;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (*this_cache == NULL)
     *this_cache = xtensa_frame_cache (this_frame, this_cache);
@@ -1422,13 +1435,13 @@ xtensa_frame_prev_register (struct frame_info *this_frame,
 
   if (regnum ==gdbarch_pc_regnum (gdbarch))
     saved_reg = cache->ra;
-  else if (regnum == gdbarch_tdep (gdbarch)->a0_base + 1)
+  else if (regnum == tdep->a0_base + 1)
     saved_reg = cache->prev_sp;
   else if (!cache->call0)
     {
-      if (regnum == gdbarch_tdep (gdbarch)->ws_regnum)
+      if (regnum == tdep->ws_regnum)
 	saved_reg = cache->wd.ws;
-      else if (regnum == gdbarch_tdep (gdbarch)->wb_regnum)
+      else if (regnum == tdep->wb_regnum)
 	saved_reg = cache->wd.wb;
       else if (regnum == gdbarch_ps_regnum (gdbarch))
 	saved_reg = cache->ps;
@@ -1445,14 +1458,14 @@ xtensa_frame_prev_register (struct frame_info *this_frame,
     {
       /* Convert A-register numbers to AR-register numbers,
 	 if we deal with A-register.  */
-      if (regnum >= gdbarch_tdep (gdbarch)->a0_base
-	  && regnum <= gdbarch_tdep (gdbarch)->a0_base + 15)
+      if (regnum >= tdep->a0_base
+	  && regnum <= tdep->a0_base + 15)
 	regnum = arreg_number (gdbarch, regnum, cache->wd.wb);
 
       /* Check, if we deal with AR-register saved on stack.  */
-      if (regnum >= gdbarch_tdep (gdbarch)->ar_base
-	  && regnum <= (gdbarch_tdep (gdbarch)->ar_base
-			 + gdbarch_tdep (gdbarch)->num_aregs))
+      if (regnum >= tdep->ar_base
+	  && regnum <= (tdep->ar_base
+			 + tdep->num_aregs))
 	{
 	  int areg = areg_number (gdbarch, regnum, cache->wd.wb);
 
@@ -1465,10 +1478,10 @@ xtensa_frame_prev_register (struct frame_info *this_frame,
     }
   else /* Call0 ABI.  */
     {
-      int reg = (regnum >= gdbarch_tdep (gdbarch)->ar_base
-		&& regnum <= (gdbarch_tdep (gdbarch)->ar_base
+      int reg = (regnum >= tdep->ar_base
+		&& regnum <= (tdep->ar_base
 			       + C0_NREGS))
-		  ? regnum - gdbarch_tdep (gdbarch)->ar_base : regnum;
+		  ? regnum - tdep->ar_base : regnum;
 
       if (reg < C0_NREGS)
 	{
@@ -1543,7 +1556,8 @@ xtensa_extract_return_value (struct type *type,
 
   gdb_assert(len > 0);
 
-  if (gdbarch_tdep (gdbarch)->call_abi != CallAbiCall0Only)
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->call_abi != CallAbiCall0Only)
     {
       /* First, we have to find the caller window in the register file.  */
       regcache_raw_read_unsigned (regcache, gdbarch_pc_regnum (gdbarch), &pc);
@@ -1558,14 +1572,14 @@ xtensa_extract_return_value (struct type *type,
       /* Get the register offset of the return
 	 register (A2) in the caller window.  */
       regcache_raw_read_unsigned
-	(regcache, gdbarch_tdep (gdbarch)->wb_regnum, &wb);
+	(regcache, tdep->wb_regnum, &wb);
       areg = arreg_number (gdbarch,
-			  gdbarch_tdep (gdbarch)->a0_base + 2 + callsize, wb);
+			  tdep->a0_base + 2 + callsize, wb);
     }
   else
     {
       /* No windowing hardware - Call0 ABI.  */
-      areg = gdbarch_tdep (gdbarch)->a0_base + C0_ARGS;
+      areg = tdep->a0_base + C0_ARGS;
     }
 
   DEBUGINFO ("[xtensa_extract_return_value] areg %d len %d\n", areg, len);
@@ -1598,10 +1612,11 @@ xtensa_store_return_value (struct type *type,
 
   DEBUGTRACE ("xtensa_store_return_value (...)\n");
 
-  if (gdbarch_tdep (gdbarch)->call_abi != CallAbiCall0Only)
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->call_abi != CallAbiCall0Only)
     {
       regcache_raw_read_unsigned 
-	(regcache, gdbarch_tdep (gdbarch)->wb_regnum, &wb);
+	(regcache, tdep->wb_regnum, &wb);
       regcache_raw_read_unsigned (regcache, gdbarch_pc_regnum (gdbarch), &pc);
       callsize = extract_call_winsize (gdbarch, pc);
 
@@ -1610,14 +1625,14 @@ xtensa_store_return_value (struct type *type,
 			_("unimplemented for this length: %s"),
 			pulongest (TYPE_LENGTH (type)));
       areg = arreg_number (gdbarch,
-			   gdbarch_tdep (gdbarch)->a0_base + 2 + callsize, wb);
+			   tdep->a0_base + 2 + callsize, wb);
 
       DEBUGTRACE ("[xtensa_store_return_value] callsize %d wb %d\n",
 	      callsize, (int) wb);
     }
   else
     {
-      areg = gdbarch_tdep (gdbarch)->a0_base + C0_ARGS;
+      areg = tdep->a0_base + C0_ARGS;
     }
 
   if (len < 4 && gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
@@ -1681,6 +1696,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
 			CORE_ADDR struct_addr)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   int size, onstack_size;
   gdb_byte *buf = (gdb_byte *) alloca (16);
   CORE_ADDR ra, ps;
@@ -1793,7 +1809,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
       size = (size + info->align - 1) & ~(info->align - 1);
       onstack_size = (onstack_size + info->align - 1) & ~(info->align - 1);
 
-      if (size + info->length > REGISTER_SIZE * ARG_NOF (gdbarch))
+      if (size + info->length > REGISTER_SIZE * ARG_NOF (tdep))
 	{
 	  info->onstack = 1;
 	  info->u.offset = onstack_size;
@@ -1802,7 +1818,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
       else
 	{
 	  info->onstack = 0;
-	  info->u.regno = ARG_1ST (gdbarch) + size / REGISTER_SIZE;
+	  info->u.regno = ARG_1ST (tdep) + size / REGISTER_SIZE;
 	}
       size += info->length;
     }
@@ -1811,7 +1827,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
   sp = align_down (sp - onstack_size, SP_ALIGNMENT);
 
   /* Simulate MOVSP, if Windowed ABI.  */
-  if ((gdbarch_tdep (gdbarch)->call_abi != CallAbiCall0Only)
+  if ((tdep->call_abi != CallAbiCall0Only)
       && (sp != osp))
     {
       read_memory (osp - 16, buf, 16);
@@ -1823,7 +1839,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
   if (return_method == return_method_struct)
     {
       store_unsigned_integer (buf, REGISTER_SIZE, byte_order, struct_addr);
-      regcache->cooked_write (ARG_1ST (gdbarch), buf);
+      regcache->cooked_write (ARG_1ST (tdep), buf);
     }
 
   for (int i = 0; i < nargs; i++)
@@ -1887,7 +1903,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
      The return address for the current function (in A0) is
      saved in the dummy frame, so we can safely overwrite A0 here.  */
 
-  if (gdbarch_tdep (gdbarch)->call_abi != CallAbiCall0Only)
+  if (tdep->call_abi != CallAbiCall0Only)
     {
       ULONGEST val;
 
@@ -1895,7 +1911,7 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
       regcache_raw_read_unsigned (regcache, gdbarch_ps_regnum (gdbarch), &val);
       ps = (unsigned long) val & ~0x00030000;
       regcache_cooked_write_unsigned
-	(regcache, gdbarch_tdep (gdbarch)->a0_base + 4, ra);
+	(regcache, tdep->a0_base + 4, ra);
       regcache_cooked_write_unsigned (regcache,
 				      gdbarch_ps_regnum (gdbarch),
 				      ps | 0x00010000);
@@ -1905,21 +1921,21 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
 	 to modify WINDOWSTART register to make it look like there
 	 is only one register window corresponding to WINDOWEBASE.  */
 
-      regcache->raw_read (gdbarch_tdep (gdbarch)->wb_regnum, buf);
+      regcache->raw_read (tdep->wb_regnum, buf);
       regcache_cooked_write_unsigned
-	(regcache, gdbarch_tdep (gdbarch)->ws_regnum,
+	(regcache, tdep->ws_regnum,
 	 1 << extract_unsigned_integer (buf, 4, byte_order));
     }
   else
     {
       /* Simulate CALL0: write RA into A0 register.  */
       regcache_cooked_write_unsigned
-	(regcache, gdbarch_tdep (gdbarch)->a0_base, bp_addr);
+	(regcache, tdep->a0_base, bp_addr);
     }
 
   /* Set new stack pointer and return it.  */
   regcache_cooked_write_unsigned (regcache,
-				  gdbarch_tdep (gdbarch)->a0_base + 1, sp);
+				  tdep->a0_base + 1, sp);
   /* Make dummy frame ID unique by adding a constant.  */
   return sp + SP_ALIGNMENT;
 }
@@ -1929,7 +1945,9 @@ xtensa_push_dummy_call (struct gdbarch *gdbarch,
 static int
 xtensa_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 {
-  if (gdbarch_tdep (gdbarch)->isa_use_density_instructions)
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  if (tdep->isa_use_density_instructions)
     return 2;
   else
     return 4;
@@ -2174,6 +2192,7 @@ call0_track_op (struct gdbarch *gdbarch, xtensa_c0reg_t dst[], xtensa_c0reg_t sr
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   unsigned litbase, litaddr, litval;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   switch (opclass)
     {
@@ -2264,9 +2283,9 @@ call0_track_op (struct gdbarch *gdbarch, xtensa_c0reg_t dst[], xtensa_c0reg_t sr
       /* 2 operands: dst, literal offset.  */
       gdb_assert (nods == 2);
       /* litbase = xtensa_get_litbase (pc);  can be also used.  */
-      litbase = (gdbarch_tdep (gdbarch)->litbase_regnum == -1)
+      litbase = (tdep->litbase_regnum == -1)
 	? 0 : xtensa_read_register
-		(gdbarch_tdep (gdbarch)->litbase_regnum);
+		(tdep->litbase_regnum);
       litaddr = litbase & 1
 		  ? (litbase & ~1) + (signed)odv[1]
 		  : (pc + 3  + (signed)odv[1]) & ~3;
@@ -2548,9 +2567,10 @@ call0_frame_cache (struct frame_info *this_frame,
   CORE_ADDR body_pc=UINT_MAX;	/* PC, where prologue analysis stopped.  */
   CORE_ADDR sp, fp, ra;
   int fp_regnum = C0_SP, c0_hasfp = 0, c0_frmsz = 0, prev_sp = 0, to_stk;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
  
   sp = get_frame_register_unsigned
-    (this_frame, gdbarch_tdep (gdbarch)->a0_base + 1);
+    (this_frame, tdep->a0_base + 1);
   fp = sp; /* Assume FP == SP until proven otherwise.  */
 
   /* Find the beginning of the prologue of the function containing the PC
@@ -2584,12 +2604,12 @@ call0_frame_cache (struct frame_info *this_frame,
 	 was derived from SP.  Otherwise, it would be C0_FP.  */
       fp_regnum = c0_hasfp ? C0_FP : C0_SP;
       c0_frmsz = - cache->c0.c0_rt[fp_regnum].fr_ofs;
-      fp_regnum += gdbarch_tdep (gdbarch)->a0_base;
+      fp_regnum += tdep->a0_base;
     }
   else  /* No data from the prologue analysis.  */
     {
       c0_hasfp = 0;
-      fp_regnum = gdbarch_tdep (gdbarch)->a0_base + C0_SP;
+      fp_regnum = tdep->a0_base + C0_SP;
       c0_frmsz = 0;
       start_pc = pc;
    }
@@ -2613,7 +2633,7 @@ call0_frame_cache (struct frame_info *this_frame,
       if (cache->c0.c0_sp_ofs == C0_NOSTK)
 	/* Saved unaligned value of SP is kept in a register.  */
 	unaligned_sp = get_frame_register_unsigned
-	  (this_frame, gdbarch_tdep (gdbarch)->a0_base + cache->c0.c0_old_sp);
+	  (this_frame, tdep->a0_base + cache->c0.c0_old_sp);
       else
 	/* Get the value from stack.  */
 	unaligned_sp = (CORE_ADDR)
@@ -2673,7 +2693,7 @@ call0_frame_cache (struct frame_info *this_frame,
 	{
 	  ra = get_frame_register_unsigned
 	    (this_frame,
-	     gdbarch_tdep (gdbarch)->a0_base + cache->c0.c0_rt[i].fr_reg);
+	     tdep->a0_base + cache->c0.c0_rt[i].fr_reg);
 	}
       else ra = 0;
     }
@@ -2700,8 +2720,9 @@ static int a11_was_saved;
 static void
 execute_l32e (struct gdbarch *gdbarch, int at, int as, int offset, CORE_ADDR wb)
 {
-  int atreg = arreg_number (gdbarch, gdbarch_tdep (gdbarch)->a0_base + at, wb);
-  int asreg = arreg_number (gdbarch, gdbarch_tdep (gdbarch)->a0_base + as, wb);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int atreg = arreg_number (gdbarch, tdep->a0_base + at, wb);
+  int asreg = arreg_number (gdbarch, tdep->a0_base + as, wb);
   CORE_ADDR addr = xtensa_read_register (asreg) + offset;
   unsigned int spilled_value
     = read_memory_unsigned_integer (addr, 4, gdbarch_byte_order (gdbarch));
@@ -2729,8 +2750,9 @@ execute_l32e (struct gdbarch *gdbarch, int at, int as, int offset, CORE_ADDR wb)
 static void
 execute_s32e (struct gdbarch *gdbarch, int at, int as, int offset, CORE_ADDR wb)
 {
-  int atreg = arreg_number (gdbarch, gdbarch_tdep (gdbarch)->a0_base + at, wb);
-  int asreg = arreg_number (gdbarch, gdbarch_tdep (gdbarch)->a0_base + as, wb);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int atreg = arreg_number (gdbarch, tdep->a0_base + at, wb);
+  int asreg = arreg_number (gdbarch, tdep->a0_base + as, wb);
   CORE_ADDR addr = xtensa_read_register (asreg) + offset;
   ULONGEST spilled_value = xtensa_read_register (atreg);
 
@@ -2762,6 +2784,7 @@ execute_code (struct gdbarch *gdbarch, CORE_ADDR current_pc, CORE_ADDR wb)
   xtensa_opcode opc;
   int insn_num = 0;
   void (*func) (struct gdbarch *, int, int, int, CORE_ADDR);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   uint32_t at, as, offset;
 
@@ -2827,7 +2850,7 @@ execute_code (struct gdbarch *gdbarch, CORE_ADDR current_pc, CORE_ADDR wb)
 	      if (a0_was_saved)
 		{
 		  int arreg = arreg_number (gdbarch,
-					    gdbarch_tdep (gdbarch)->a0_base,
+					    tdep->a0_base,
 					    wb);
 		  xtensa_write_register (arreg, a0_saved);
 		}
@@ -2840,7 +2863,7 @@ execute_code (struct gdbarch *gdbarch, CORE_ADDR current_pc, CORE_ADDR wb)
 		  if (a11_was_saved)
 		    {
 		      int arreg = arreg_number (gdbarch,
-						gdbarch_tdep (gdbarch)->a0_base + 11,
+						tdep->a0_base + 11,
 						wb);
 		      xtensa_write_register (arreg, a11_saved);
 		    }
@@ -2848,7 +2871,7 @@ execute_code (struct gdbarch *gdbarch, CORE_ADDR current_pc, CORE_ADDR wb)
 	      else if (a7_was_saved)
 		{
 		  int arreg = arreg_number (gdbarch,
-					    gdbarch_tdep (gdbarch)->a0_base + 7,
+					    tdep->a0_base + 7,
 					    wb);
 		  xtensa_write_register (arreg, a7_saved);
 		}
@@ -2892,12 +2915,13 @@ xtensa_window_interrupt_frame_cache (struct frame_info *this_frame,
   CORE_ADDR ps, wb, ws, ra;
   int epc1_regnum, i, regnum;
   xtensa_exception_handler_t eh_type;
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   /* Read PS, WB, and WS from the hardware. Note that PS register
      must be present, if Windowed ABI is supported.  */
   ps = xtensa_read_register (gdbarch_ps_regnum (gdbarch));
-  wb = xtensa_read_register (gdbarch_tdep (gdbarch)->wb_regnum);
-  ws = xtensa_read_register (gdbarch_tdep (gdbarch)->ws_regnum);
+  wb = xtensa_read_register (tdep->wb_regnum);
+  ws = xtensa_read_register (tdep->ws_regnum);
 
   /* Execute all the remaining instructions from Window Interrupt Handler
      by simulating them on the remote protocol level.  On return, set the
@@ -2920,7 +2944,7 @@ Unable to decode Xtensa Window Interrupt Handler's code."));
     cache->wd.ws = ws | (1 << wb);
 
   cache->wd.wb = (ps & 0xf00) >> 8; /* Set WB to OWB.  */
-  regnum = arreg_number (gdbarch, gdbarch_tdep (gdbarch)->a0_base,
+  regnum = arreg_number (gdbarch, tdep->a0_base,
 			 cache->wd.wb);
   ra = xtensa_read_register (regnum);
   cache->wd.callsize = WINSIZE (ra);
@@ -2928,7 +2952,7 @@ Unable to decode Xtensa Window Interrupt Handler's code."));
   /* Set regnum to a frame pointer of the frame being cached.  */
   regnum = xtensa_scan_prologue (gdbarch, pc);
   regnum = arreg_number (gdbarch,
-			 gdbarch_tdep (gdbarch)->a0_base + regnum,
+			 tdep->a0_base + regnum,
 			 cache->wd.wb);
   cache->base = get_frame_register_unsigned (this_frame, regnum);
 
@@ -3005,7 +3029,8 @@ xtensa_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
 
       CORE_ADDR end_func;
 
-      if ((gdbarch_tdep (gdbarch)->call_abi == CallAbiCall0Only)
+      xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+      if ((tdep->call_abi == CallAbiCall0Only)
 	  && call0_ret (start_pc, prologue_sal.end))
 	return start_pc;
 
@@ -3026,7 +3051,7 @@ xtensa_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc)
 static void
 xtensa_verify_config (struct gdbarch *gdbarch)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  xtensa_gdbarch_tdep *tdep = (xtensa_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   string_file log;
 
   /* Verify that we got a reasonable number of AREGS.  */
@@ -3064,7 +3089,7 @@ xtensa_verify_config (struct gdbarch *gdbarch)
 /* Derive specific register numbers from the array of registers.  */
 
 static void
-xtensa_derive_tdep (struct gdbarch_tdep *tdep)
+xtensa_derive_tdep (xtensa_gdbarch_tdep *tdep)
 {
   xtensa_register_t* rmap;
   int n, max_size = 4;
@@ -3139,12 +3164,11 @@ xtensa_derive_tdep (struct gdbarch_tdep *tdep)
 
 /* Module "constructor" function.  */
 
-extern struct gdbarch_tdep xtensa_tdep;
+extern xtensa_gdbarch_tdep xtensa_tdep;
 
 static struct gdbarch *
 xtensa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
 
   DEBUGTRACE ("gdbarch_init()\n");
@@ -3155,7 +3179,7 @@ xtensa_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* We have to set the byte order before we call gdbarch_alloc.  */
   info.byte_order = XCHAL_HAVE_BE ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
 
-  tdep = &xtensa_tdep;
+  xtensa_gdbarch_tdep *tdep = &xtensa_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
   xtensa_derive_tdep (tdep);
 
diff --git a/gdb/xtensa-tdep.h b/gdb/xtensa-tdep.h
index 55a2ed4..64e4da6 100644
--- a/gdb/xtensa-tdep.h
+++ b/gdb/xtensa-tdep.h
@@ -21,6 +21,8 @@
 #define XTENSA_TDEP_H
 
 #include "arch/xtensa.h"
+#include "gdbarch.h"
+#include "xtensa-config.h"
 
 /* XTENSA_TDEP_VERSION can/should be changed along with XTENSA_CONFIG_VERSION
    whenever the "tdep" structure changes in an incompatible way.  */
@@ -155,137 +157,91 @@ struct ctype_cache
   struct type *virtual_type;
 };
 
+#ifndef XCHAL_NUM_CONTEXTS
+# define XCHAL_NUM_CONTEXTS	0
+#endif
+
+#ifndef XCHAL_HAVE_EXCEPTIONS
+# define XCHAL_HAVE_EXCEPTIONS	1
+#endif
+
 /*  Xtensa-specific target dependencies.  */
 
-struct gdbarch_tdep
+struct xtensa_gdbarch_tdep : gdbarch_tdep
 {
-  unsigned int target_flags;
+  xtensa_gdbarch_tdep (xtensa_register_t *regmap)
+    : regmap (regmap)
+  {}
+
+  unsigned int target_flags = 0;
 
   /* Spill location for TIE register files under ocd.  */
 
-  unsigned int spill_location;
-  unsigned int spill_size;
+  unsigned int spill_location = (unsigned int) -1;
+  unsigned int spill_size = 0;
 
-  char *unused;				/* Placeholder for compatibility.  */
-  call_abi_t call_abi;			/* Calling convention.  */
+  char *unused = nullptr;		/* Placeholder for compatibility.  */
+
+  /* Calling convention.  */
+  call_abi_t call_abi = (XSHAL_ABI == XTHAL_ABI_CALL0
+			 ? CallAbiCall0Only : CallAbiDefault);
 
   /* CPU configuration.  */
 
-  unsigned int debug_interrupt_level;
+  unsigned int debug_interrupt_level = XCHAL_DEBUGLEVEL;
 
-  unsigned int icache_line_bytes;
-  unsigned int dcache_line_bytes;
-  unsigned int dcache_writeback;
+  unsigned int icache_line_bytes = XCHAL_ICACHE_LINESIZE;
+  unsigned int dcache_line_bytes = XCHAL_DCACHE_LINESIZE;
+  unsigned int dcache_writeback = XCHAL_DCACHE_IS_WRITEBACK;
 
-  unsigned int isa_use_windowed_registers;
-  unsigned int isa_use_density_instructions;
-  unsigned int isa_use_exceptions;
-  unsigned int isa_use_ext_l32r;
-  unsigned int isa_max_insn_size;	/* Maximum instruction length.  */
-  unsigned int debug_num_ibreaks;	/* Number of IBREAKs.  */
-  unsigned int debug_num_dbreaks;
+  unsigned int isa_use_windowed_registers = XSHAL_ABI != XTHAL_ABI_CALL0;
+  unsigned int isa_use_density_instructions = XCHAL_HAVE_DENSITY;
+  unsigned int isa_use_exceptions = XCHAL_HAVE_EXCEPTIONS;
+  unsigned int isa_use_ext_l32r = XSHAL_USE_ABSOLUTE_LITERALS;
+  unsigned int isa_max_insn_size = XCHAL_MAX_INSTRUCTION_SIZE;	/* Maximum instruction length.  */
+  unsigned int debug_num_ibreaks = XCHAL_NUM_IBREAK;	/* Number of IBREAKs.  */
+  unsigned int debug_num_dbreaks = XCHAL_NUM_DBREAK;
 
   /* Register map.  */
 
-  xtensa_register_t* regmap;
+  xtensa_register_t *regmap;
 
-  unsigned int num_regs;	/* Number of registers in register map.  */
-  unsigned int num_nopriv_regs;	/* Number of non-privileged registers.  */
-  unsigned int num_pseudo_regs;	/* Number of pseudo registers.  */
-  unsigned int num_aregs;	/* Size of register file.  */
-  unsigned int num_contexts;
+  unsigned int num_regs = 0;		/* Number of registers in register map.  */
+  unsigned int num_nopriv_regs = 0;	/* Number of non-privileged registers.  */
+  unsigned int num_pseudo_regs = 0;	/* Number of pseudo registers.  */
+  unsigned int num_aregs = XCHAL_NUM_AREGS;		/* Size of register file.  */
+  unsigned int num_contexts = XCHAL_NUM_CONTEXTS;
 
-  int ar_base;			/* Register number for AR0.  */
-  int a0_base;			/* Register number for A0 (pseudo).  */
-  int wb_regnum;		/* Register number for WB.  */
-  int ws_regnum;		/* Register number for WS.  */
-  int pc_regnum;		/* Register number for PC.  */
-  int ps_regnum;		/* Register number for PS.  */
-  int lbeg_regnum;		/* Register numbers for count regs.  */
-  int lend_regnum;
-  int lcount_regnum;
-  int sar_regnum;		/* Register number of SAR.  */
-  int litbase_regnum;		/* Register number of LITBASE.  */
-  int threadptr_regnum;		/* Register number of THREADPTR.  */
+  int ar_base = -1;		/* Register number for AR0.  */
+  int a0_base = -1;		/* Register number for A0 (pseudo).  */
+  int wb_regnum = -1;		/* Register number for WB.  */
+  int ws_regnum = -1;		/* Register number for WS.  */
+  int pc_regnum = -1;		/* Register number for PC.  */
+  int ps_regnum = -1;		/* Register number for PS.  */
+  int lbeg_regnum = -1;		/* Register numbers for count regs.  */
+  int lend_regnum = -1;
+  int lcount_regnum = -1;
+  int sar_regnum = -1;		/* Register number of SAR.  */
+  int litbase_regnum = -1;	/* Register number of LITBASE.  */
+  int threadptr_regnum = -1;	/* Register number of THREADPTR.  */
 
-  int interrupt_regnum;		/* Register number for interrupt.  */
-  int interrupt2_regnum;	/* Register number for interrupt2.  */
-  int cpenable_regnum;		/* Register number for cpenable.  */
-  int debugcause_regnum;	/* Register number for debugcause.  */
-  int exccause_regnum;		/* Register number for exccause.  */
-  int excvaddr_regnum;		/* Register number for excvaddr.  */
+  int interrupt_regnum = -1;	/* Register number for interrupt.  */
+  int interrupt2_regnum = -1;	/* Register number for interrupt2.  */
+  int cpenable_regnum = -1;	/* Register number for cpenable.  */
+  int debugcause_regnum = -1;	/* Register number for debugcause.  */
+  int exccause_regnum = -1;	/* Register number for exccause.  */
+  int excvaddr_regnum = -1;	/* Register number for excvaddr.  */
 
-  int max_register_raw_size;
-  int max_register_virtual_size;
-  unsigned long *fp_layout;	/* Layout of custom/TIE regs in 'FP' area.  */
-  unsigned int fp_layout_bytes;	/* Size of layout information (in bytes).  */
-  unsigned long *gregmap;
+  int max_register_raw_size = 0;
+  int max_register_virtual_size = 0;
+  unsigned long *fp_layout = nullptr;	/* Layout of custom/TIE regs in 'FP' area.  */
+  unsigned int fp_layout_bytes = 0;	/* Size of layout information (in bytes).  */
+  unsigned long *gregmap = nullptr;
 
   /* Cached register types.  */
-  struct ctype_cache *type_entries;
+  struct ctype_cache *type_entries = nullptr;
 };
 
-/* Macro to instantiate a gdbarch_tdep structure.  */
-
-#define XTENSA_GDBARCH_TDEP_INSTANTIATE(rmap,spillsz)			\
-  {									\
-    0,				/* target_flags */			\
-    (unsigned) -1,		/* spill_location */	\
-    (spillsz),			/* spill_size */			\
-    0,				/* unused */				\
-    (XSHAL_ABI == XTHAL_ABI_CALL0					\
-     ? CallAbiCall0Only							\
-     : CallAbiDefault),		/* call_abi */				\
-    XCHAL_DEBUGLEVEL,		/* debug_interrupt_level */		\
-    XCHAL_ICACHE_LINESIZE,	/* icache_line_bytes */			\
-    XCHAL_DCACHE_LINESIZE,	/* dcache_line_bytes */			\
-    XCHAL_DCACHE_IS_WRITEBACK,  /* dcache_writeback */			\
-    (XSHAL_ABI != XTHAL_ABI_CALL0),   /* isa_use_windowed_registers */	\
-    XCHAL_HAVE_DENSITY,		 /* isa_use_density_instructions */	\
-    XCHAL_HAVE_EXCEPTIONS,	 /* isa_use_exceptions */		\
-    XSHAL_USE_ABSOLUTE_LITERALS, /* isa_use_ext_l32r */			\
-    XCHAL_MAX_INSTRUCTION_SIZE,  /* isa_max_insn_size */		\
-    XCHAL_NUM_IBREAK,		 /* debug_num_ibreaks */		\
-    XCHAL_NUM_DBREAK,		 /* debug_num_dbreaks */		\
-    rmap,			 /* regmap */				\
-    0,				 /* num_regs */				\
-    0,				 /* num_nopriv_regs */			\
-    0,				 /* num_pseudo_regs */			\
-    XCHAL_NUM_AREGS,		 /* num_aregs */			\
-    XCHAL_NUM_CONTEXTS,		 /* num_contexts */			\
-    -1,				 /* ar_base */				\
-    -1,				 /* a0_base */				\
-    -1,				 /* wb_regnum */			\
-    -1,				 /* ws_regnum */			\
-    -1,				 /* pc_regnum */			\
-    -1,				 /* ps_regnum */			\
-    -1,				 /* lbeg_regnum */			\
-    -1,				 /* lend_regnum */			\
-    -1,				 /* lcount_regnum */			\
-    -1,				 /* sar_regnum */			\
-    -1,				 /* litbase_regnum */			\
-    -1,				 /* interrupt_regnum */			\
-    -1,				 /* interrupt2_regnum */		\
-    -1,				 /* cpenable_regnum */			\
-    -1,				 /* debugcause_regnum */		\
-    -1,				 /* exccause_regnum */			\
-    -1,				 /* excvaddr_regnum */			\
-    0,				 /* max_register_raw_size */		\
-    0,				 /* max_register_virtual_size */	\
-    0,				 /* fp_layout */			\
-    0,				 /* fp_layout_bytes */			\
-    0,				 /* gregmap */				\
-  }
-#define XTENSA_CONFIG_INSTANTIATE(rmap,spill_size)	\
-	struct gdbarch_tdep xtensa_tdep = \
-	  XTENSA_GDBARCH_TDEP_INSTANTIATE(rmap,spill_size);
-
-#ifndef XCHAL_NUM_CONTEXTS
-#define XCHAL_NUM_CONTEXTS	0
-#endif
-#ifndef XCHAL_HAVE_EXCEPTIONS
-#define XCHAL_HAVE_EXCEPTIONS	1
-#endif
 #define WB_SHIFT	  2
 
 /* We assign fixed numbers to the registers of the "current" window 
diff --git a/gdb/z80-tdep.c b/gdb/z80-tdep.c
index 7b9a7e2..9d453cd 100644
--- a/gdb/z80-tdep.c
+++ b/gdb/z80-tdep.c
@@ -54,19 +54,21 @@
      next frame - frame of caller, which has called current function
 */
 
-struct gdbarch_tdep
+struct z80_gdbarch_tdep : gdbarch_tdep
 {
   /* Number of bytes used for address:
       2 bytes for all Z80 family
       3 bytes for eZ80 CPUs operating in ADL mode */
-  int addr_length;
+  int addr_length = 0;
 
   /* Type for void.  */
-  struct type *void_type;
+  struct type *void_type = nullptr;
+
   /* Type for a function returning void.  */
-  struct type *func_void_type;
+  struct type *func_void_type = nullptr;
+
   /* Type for a pointer to a function.  Used for the type of PC.  */
-  struct type *pc_type;
+  struct type *pc_type = nullptr;
 };
 
 /* At any time stack frame contains following parts:
@@ -305,7 +307,8 @@ z80_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR pc_beg, CORE_ADDR pc_end,
 		   struct z80_unwind_cache *info)
 {
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  int addr_len = gdbarch_tdep (gdbarch)->addr_length;
+  z80_gdbarch_tdep *tdep = (z80_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int addr_len = tdep->addr_length;
   gdb_byte prologue[32]; /* max prologue is 24 bytes: __interrupt with local array */
   int pos = 0;
   int len;
@@ -560,7 +563,8 @@ z80_frame_unwind_cache (struct frame_info *this_frame,
   gdb_byte buf[sizeof(void*)];
   struct z80_unwind_cache *info;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  int addr_len = gdbarch_tdep (gdbarch)->addr_length;
+  z80_gdbarch_tdep *tdep = (z80_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int addr_len = tdep->addr_length;
 
   if (*this_prologue_cache)
     return (struct z80_unwind_cache *) *this_prologue_cache;
@@ -692,7 +696,7 @@ z80_frame_prev_register (struct frame_info *this_frame,
 	  ULONGEST pc;
 	  gdb_byte buf[3];
 	  struct gdbarch *gdbarch = get_frame_arch (this_frame);
-	  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+	  z80_gdbarch_tdep *tdep = (z80_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 	  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 
 	  read_memory (info->saved_regs[Z80_PC_REGNUM].addr (),
@@ -745,11 +749,12 @@ z80_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
     }
   else /* kind is non-RST address, use CALL instead, but it is dungerous */
     {
+      z80_gdbarch_tdep *tdep = (z80_gdbarch_tdep *) gdbarch_tdep (gdbarch);
       gdb_byte *p = break_insn;
       *p++ = 0xcd;
       *p++ = (kind >> 0) & 0xff;
       *p++ = (kind >> 8) & 0xff;
-      if (gdbarch_tdep (gdbarch)->addr_length > 2)
+      if (tdep->addr_length > 2)
 	*p++ = (kind >> 16) & 0xff;
       *size = p - break_insn;
     }
@@ -1077,7 +1082,6 @@ static struct gdbarch *
 z80_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   struct gdbarch_list *best_arch;
   tdesc_arch_data_up tdesc_data;
   unsigned long mach = info.bfd_arch_info->mach;
@@ -1119,7 +1123,7 @@ z80_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
     }
 
   /* None found, create a new architecture from the information provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  z80_gdbarch_tdep *tdep = new z80_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   if (mach == bfd_mach_ez80_adl)