| /* Target-dependent code for the VAX. |
| |
| Copyright (C) 1986-2021 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "arch-utils.h" |
| #include "dis-asm.h" |
| #include "frame.h" |
| #include "frame-base.h" |
| #include "frame-unwind.h" |
| #include "gdbcore.h" |
| #include "gdbtypes.h" |
| #include "osabi.h" |
| #include "regcache.h" |
| #include "regset.h" |
| #include "trad-frame.h" |
| #include "value.h" |
| |
| #include "vax-tdep.h" |
| |
| /* Return the name of register REGNUM. */ |
| |
| static const char * |
| vax_register_name (struct gdbarch *gdbarch, int regnum) |
| { |
| static const char *register_names[] = |
| { |
| "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", |
| "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc", |
| "ps", |
| }; |
| |
| if (regnum >= 0 && regnum < ARRAY_SIZE (register_names)) |
| return register_names[regnum]; |
| |
| return NULL; |
| } |
| |
| /* Return the GDB type object for the "standard" data type of data in |
| register REGNUM. */ |
| |
| static struct type * |
| vax_register_type (struct gdbarch *gdbarch, int regnum) |
| { |
| return builtin_type (gdbarch)->builtin_int; |
| } |
| |
| /* Core file support. */ |
| |
| /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| in the general-purpose register set REGSET to register cache |
| REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| |
| static void |
| vax_supply_gregset (const struct regset *regset, struct regcache *regcache, |
| int regnum, const void *gregs, size_t len) |
| { |
| const gdb_byte *regs = (const gdb_byte *) gregs; |
| int i; |
| |
| for (i = 0; i < VAX_NUM_REGS; i++) |
| { |
| if (regnum == i || regnum == -1) |
| regcache->raw_supply (i, regs + i * 4); |
| } |
| } |
| |
| /* VAX register set. */ |
| |
| static const struct regset vax_gregset = |
| { |
| NULL, |
| vax_supply_gregset |
| }; |
| |
| /* Iterate over core file register note sections. */ |
| |
| static void |
| vax_iterate_over_regset_sections (struct gdbarch *gdbarch, |
| iterate_over_regset_sections_cb *cb, |
| void *cb_data, |
| const struct regcache *regcache) |
| { |
| cb (".reg", VAX_NUM_REGS * 4, VAX_NUM_REGS * 4, &vax_gregset, NULL, cb_data); |
| } |
| |
| /* The VAX UNIX calling convention uses R1 to pass a structure return |
| value address instead of passing it as a first (hidden) argument as |
| the VMS calling convention suggests. */ |
| |
| static CORE_ADDR |
| vax_store_arguments (struct regcache *regcache, int nargs, |
| struct value **args, CORE_ADDR sp) |
| { |
| struct gdbarch *gdbarch = regcache->arch (); |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| gdb_byte buf[4]; |
| int count = 0; |
| int i; |
| |
| /* We create an argument list on the stack, and make the argument |
| pointer to it. */ |
| |
| /* Push arguments in reverse order. */ |
| for (i = nargs - 1; i >= 0; i--) |
| { |
| int len = TYPE_LENGTH (value_enclosing_type (args[i])); |
| |
| sp -= (len + 3) & ~3; |
| count += (len + 3) / 4; |
| write_memory (sp, value_contents_all (args[i]), len); |
| } |
| |
| /* Push argument count. */ |
| sp -= 4; |
| store_unsigned_integer (buf, 4, byte_order, count); |
| write_memory (sp, buf, 4); |
| |
| /* Update the argument pointer. */ |
| store_unsigned_integer (buf, 4, byte_order, sp); |
| regcache->cooked_write (VAX_AP_REGNUM, buf); |
| |
| return sp; |
| } |
| |
| static CORE_ADDR |
| vax_push_dummy_call (struct gdbarch *gdbarch, struct value *function, |
| struct regcache *regcache, CORE_ADDR bp_addr, int nargs, |
| struct value **args, CORE_ADDR sp, |
| function_call_return_method return_method, |
| CORE_ADDR struct_addr) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| CORE_ADDR fp = sp; |
| gdb_byte buf[4]; |
| |
| /* Set up the function arguments. */ |
| sp = vax_store_arguments (regcache, nargs, args, sp); |
| |
| /* Store return value address. */ |
| if (return_method == return_method_struct) |
| regcache_cooked_write_unsigned (regcache, VAX_R1_REGNUM, struct_addr); |
| |
| /* Store return address in the PC slot. */ |
| sp -= 4; |
| store_unsigned_integer (buf, 4, byte_order, bp_addr); |
| write_memory (sp, buf, 4); |
| |
| /* Store the (fake) frame pointer in the FP slot. */ |
| sp -= 4; |
| store_unsigned_integer (buf, 4, byte_order, fp); |
| write_memory (sp, buf, 4); |
| |
| /* Skip the AP slot. */ |
| sp -= 4; |
| |
| /* Store register save mask and control bits. */ |
| sp -= 4; |
| store_unsigned_integer (buf, 4, byte_order, 0); |
| write_memory (sp, buf, 4); |
| |
| /* Store condition handler. */ |
| sp -= 4; |
| store_unsigned_integer (buf, 4, byte_order, 0); |
| write_memory (sp, buf, 4); |
| |
| /* Update the stack pointer and frame pointer. */ |
| store_unsigned_integer (buf, 4, byte_order, sp); |
| regcache->cooked_write (VAX_SP_REGNUM, buf); |
| regcache->cooked_write (VAX_FP_REGNUM, buf); |
| |
| /* Return the saved (fake) frame pointer. */ |
| return fp; |
| } |
| |
| static struct frame_id |
| vax_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame) |
| { |
| CORE_ADDR fp; |
| |
| fp = get_frame_register_unsigned (this_frame, VAX_FP_REGNUM); |
| return frame_id_build (fp, get_frame_pc (this_frame)); |
| } |
| |
| |
| static enum return_value_convention |
| vax_return_value (struct gdbarch *gdbarch, struct value *function, |
| struct type *type, struct regcache *regcache, |
| gdb_byte *readbuf, const gdb_byte *writebuf) |
| { |
| int len = TYPE_LENGTH (type); |
| gdb_byte buf[8]; |
| |
| if (type->code () == TYPE_CODE_STRUCT |
| || type->code () == TYPE_CODE_UNION |
| || type->code () == TYPE_CODE_ARRAY) |
| { |
| /* The default on VAX is to return structures in static memory. |
| Consequently a function must return the address where we can |
| find the return value. */ |
| |
| if (readbuf) |
| { |
| ULONGEST addr; |
| |
| regcache_raw_read_unsigned (regcache, VAX_R0_REGNUM, &addr); |
| read_memory (addr, readbuf, len); |
| } |
| |
| return RETURN_VALUE_ABI_RETURNS_ADDRESS; |
| } |
| |
| if (readbuf) |
| { |
| /* Read the contents of R0 and (if necessary) R1. */ |
| regcache->cooked_read (VAX_R0_REGNUM, buf); |
| if (len > 4) |
| regcache->cooked_read (VAX_R1_REGNUM, buf + 4); |
| memcpy (readbuf, buf, len); |
| } |
| if (writebuf) |
| { |
| /* Read the contents to R0 and (if necessary) R1. */ |
| memcpy (buf, writebuf, len); |
| regcache->cooked_write (VAX_R0_REGNUM, buf); |
| if (len > 4) |
| regcache->cooked_write (VAX_R1_REGNUM, buf + 4); |
| } |
| |
| return RETURN_VALUE_REGISTER_CONVENTION; |
| } |
| |
| |
| /* Use the program counter to determine the contents and size of a |
| breakpoint instruction. Return a pointer to a string of bytes that |
| encode a breakpoint instruction, store the length of the string in |
| *LEN and optionally adjust *PC to point to the correct memory |
| location for inserting the breakpoint. */ |
| |
| constexpr gdb_byte vax_break_insn[] = { 3 }; |
| |
| typedef BP_MANIPULATION (vax_break_insn) vax_breakpoint; |
| |
| /* Advance PC across any function entry prologue instructions |
| to reach some "real" code. */ |
| |
| static CORE_ADDR |
| vax_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| gdb_byte op = read_memory_unsigned_integer (pc, 1, byte_order); |
| |
| if (op == 0x11) |
| pc += 2; /* skip brb */ |
| if (op == 0x31) |
| pc += 3; /* skip brw */ |
| if (op == 0xC2 |
| && read_memory_unsigned_integer (pc + 2, 1, byte_order) == 0x5E) |
| pc += 3; /* skip subl2 */ |
| if (op == 0x9E |
| && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xAE |
| && read_memory_unsigned_integer (pc + 3, 1, byte_order) == 0x5E) |
| pc += 4; /* skip movab */ |
| if (op == 0x9E |
| && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xCE |
| && read_memory_unsigned_integer (pc + 4, 1, byte_order) == 0x5E) |
| pc += 5; /* skip movab */ |
| if (op == 0x9E |
| && read_memory_unsigned_integer (pc + 1, 1, byte_order) == 0xEE |
| && read_memory_unsigned_integer (pc + 6, 1, byte_order) == 0x5E) |
| pc += 7; /* skip movab */ |
| |
| return pc; |
| } |
| |
| |
| /* Unwinding the stack is relatively easy since the VAX has a |
| dedicated frame pointer, and frames are set up automatically as the |
| result of a function call. Most of the relevant information can be |
| inferred from the documentation of the Procedure Call Instructions |
| in the VAX MACRO and Instruction Set Reference Manual. */ |
| |
| struct vax_frame_cache |
| { |
| /* Base address. */ |
| CORE_ADDR base; |
| |
| /* Table of saved registers. */ |
| trad_frame_saved_reg *saved_regs; |
| }; |
| |
| static struct vax_frame_cache * |
| vax_frame_cache (struct frame_info *this_frame, void **this_cache) |
| { |
| struct vax_frame_cache *cache; |
| CORE_ADDR addr; |
| ULONGEST mask; |
| int regnum; |
| |
| if (*this_cache) |
| return (struct vax_frame_cache *) *this_cache; |
| |
| /* Allocate a new cache. */ |
| cache = FRAME_OBSTACK_ZALLOC (struct vax_frame_cache); |
| cache->saved_regs = trad_frame_alloc_saved_regs (this_frame); |
| |
| /* The frame pointer is used as the base for the frame. */ |
| cache->base = get_frame_register_unsigned (this_frame, VAX_FP_REGNUM); |
| if (cache->base == 0) |
| return cache; |
| |
| /* The register save mask and control bits determine the layout of |
| the stack frame. */ |
| mask = get_frame_memory_unsigned (this_frame, cache->base + 4, 4) >> 16; |
| |
| /* These are always saved. */ |
| cache->saved_regs[VAX_PC_REGNUM].set_addr (cache->base + 16); |
| cache->saved_regs[VAX_FP_REGNUM].set_addr (cache->base + 12); |
| cache->saved_regs[VAX_AP_REGNUM].set_addr (cache->base + 8); |
| cache->saved_regs[VAX_PS_REGNUM].set_addr (cache->base + 4); |
| |
| /* Scan the register save mask and record the location of the saved |
| registers. */ |
| addr = cache->base + 20; |
| for (regnum = 0; regnum < VAX_AP_REGNUM; regnum++) |
| { |
| if (mask & (1 << regnum)) |
| { |
| cache->saved_regs[regnum].set_addr (addr); |
| addr += 4; |
| } |
| } |
| |
| /* The CALLS/CALLG flag determines whether this frame has a General |
| Argument List or a Stack Argument List. */ |
| if (mask & (1 << 13)) |
| { |
| ULONGEST numarg; |
| |
| /* This is a procedure with Stack Argument List. Adjust the |
| stack address for the arguments that were pushed onto the |
| stack. The return instruction will automatically pop the |
| arguments from the stack. */ |
| numarg = get_frame_memory_unsigned (this_frame, addr, 1); |
| addr += 4 + numarg * 4; |
| } |
| |
| /* Bits 1:0 of the stack pointer were saved in the control bits. */ |
| cache->saved_regs[VAX_SP_REGNUM].set_value (addr + (mask >> 14)); |
| |
| return cache; |
| } |
| |
| static void |
| vax_frame_this_id (struct frame_info *this_frame, void **this_cache, |
| struct frame_id *this_id) |
| { |
| struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache); |
| |
| /* This marks the outermost frame. */ |
| if (cache->base == 0) |
| return; |
| |
| (*this_id) = frame_id_build (cache->base, get_frame_func (this_frame)); |
| } |
| |
| static struct value * |
| vax_frame_prev_register (struct frame_info *this_frame, |
| void **this_cache, int regnum) |
| { |
| struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache); |
| |
| return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum); |
| } |
| |
| static const struct frame_unwind vax_frame_unwind = |
| { |
| "vax prologue", |
| NORMAL_FRAME, |
| default_frame_unwind_stop_reason, |
| vax_frame_this_id, |
| vax_frame_prev_register, |
| NULL, |
| default_frame_sniffer |
| }; |
| |
| |
| static CORE_ADDR |
| vax_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| { |
| struct vax_frame_cache *cache = vax_frame_cache (this_frame, this_cache); |
| |
| return cache->base; |
| } |
| |
| static CORE_ADDR |
| vax_frame_args_address (struct frame_info *this_frame, void **this_cache) |
| { |
| return get_frame_register_unsigned (this_frame, VAX_AP_REGNUM); |
| } |
| |
| static const struct frame_base vax_frame_base = |
| { |
| &vax_frame_unwind, |
| vax_frame_base_address, |
| vax_frame_base_address, |
| vax_frame_args_address |
| }; |
| |
| /* Return number of arguments for FRAME. */ |
| |
| static int |
| vax_frame_num_args (struct frame_info *frame) |
| { |
| CORE_ADDR args; |
| |
| /* Assume that the argument pointer for the outermost frame is |
| hosed, as is the case on NetBSD/vax ELF. */ |
| if (get_frame_base_address (frame) == 0) |
| return 0; |
| |
| args = get_frame_register_unsigned (frame, VAX_AP_REGNUM); |
| return get_frame_memory_unsigned (frame, args, 1); |
| } |
| |
| |
| |
| /* Initialize the current architecture based on INFO. If possible, re-use an |
| architecture from ARCHES, which is a list of architectures already created |
| during this debugging session. |
| |
| Called e.g. at program startup, when reading a core file, and when reading |
| a binary file. */ |
| |
| static struct gdbarch * |
| vax_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) |
| { |
| struct gdbarch *gdbarch; |
| |
| /* If there is already a candidate, use it. */ |
| arches = gdbarch_list_lookup_by_info (arches, &info); |
| if (arches != NULL) |
| return arches->gdbarch; |
| |
| gdbarch = gdbarch_alloc (&info, NULL); |
| |
| set_gdbarch_float_format (gdbarch, floatformats_vax_f); |
| set_gdbarch_double_format (gdbarch, floatformats_vax_d); |
| set_gdbarch_long_double_format (gdbarch, floatformats_vax_d); |
| set_gdbarch_long_double_bit (gdbarch, 64); |
| |
| /* Register info */ |
| set_gdbarch_num_regs (gdbarch, VAX_NUM_REGS); |
| set_gdbarch_register_name (gdbarch, vax_register_name); |
| set_gdbarch_register_type (gdbarch, vax_register_type); |
| set_gdbarch_sp_regnum (gdbarch, VAX_SP_REGNUM); |
| set_gdbarch_pc_regnum (gdbarch, VAX_PC_REGNUM); |
| set_gdbarch_ps_regnum (gdbarch, VAX_PS_REGNUM); |
| |
| set_gdbarch_iterate_over_regset_sections |
| (gdbarch, vax_iterate_over_regset_sections); |
| |
| /* Frame and stack info */ |
| set_gdbarch_skip_prologue (gdbarch, vax_skip_prologue); |
| set_gdbarch_frame_num_args (gdbarch, vax_frame_num_args); |
| set_gdbarch_frame_args_skip (gdbarch, 4); |
| |
| /* Stack grows downward. */ |
| set_gdbarch_inner_than (gdbarch, core_addr_lessthan); |
| |
| /* Return value info */ |
| set_gdbarch_return_value (gdbarch, vax_return_value); |
| |
| /* Call dummy code. */ |
| set_gdbarch_push_dummy_call (gdbarch, vax_push_dummy_call); |
| set_gdbarch_dummy_id (gdbarch, vax_dummy_id); |
| |
| /* Breakpoint info */ |
| set_gdbarch_breakpoint_kind_from_pc (gdbarch, vax_breakpoint::kind_from_pc); |
| set_gdbarch_sw_breakpoint_from_kind (gdbarch, vax_breakpoint::bp_from_kind); |
| |
| /* Misc info */ |
| set_gdbarch_deprecated_function_start_offset (gdbarch, 2); |
| set_gdbarch_believe_pcc_promotion (gdbarch, 1); |
| |
| frame_base_set_default (gdbarch, &vax_frame_base); |
| |
| /* Hook in ABI-specific overrides, if they have been registered. */ |
| gdbarch_init_osabi (info, gdbarch); |
| |
| frame_unwind_append_unwinder (gdbarch, &vax_frame_unwind); |
| |
| return (gdbarch); |
| } |
| |
| void _initialize_vax_tdep (); |
| void |
| _initialize_vax_tdep () |
| { |
| gdbarch_register (bfd_arch_vax, vax_gdbarch_init, NULL); |
| } |