| /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
| |
| Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, |
| 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 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 2 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, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| |
| #include "defs.h" |
| #include "dummy-frame.h" |
| #include "regcache.h" |
| #include "frame.h" |
| #include "inferior.h" |
| #include "gdb_assert.h" |
| #include "frame-unwind.h" |
| #include "command.h" |
| #include "gdbcmd.h" |
| |
| static void dummy_frame_this_id (struct frame_info *next_frame, |
| void **this_prologue_cache, |
| struct frame_id *this_id); |
| |
| /* Dummy frame. This saves the processor state just prior to setting |
| up the inferior function call. Older targets save the registers |
| on the target stack (but that really slows down function calls). */ |
| |
| struct dummy_frame |
| { |
| struct dummy_frame *next; |
| |
| /* These values belong to the caller (the previous frame, the frame |
| that this unwinds back to). */ |
| CORE_ADDR pc; |
| CORE_ADDR fp; |
| CORE_ADDR sp; |
| CORE_ADDR top; |
| struct frame_id id; |
| struct regcache *regcache; |
| |
| /* Address range of the call dummy code. Look for PC in the range |
| [LO..HI) (after allowing for DECR_PC_AFTER_BREAK). */ |
| CORE_ADDR call_lo; |
| CORE_ADDR call_hi; |
| }; |
| |
| static struct dummy_frame *dummy_frame_stack = NULL; |
| |
| /* Function: find_dummy_frame(pc, fp, sp) |
| |
| Search the stack of dummy frames for one matching the given PC and |
| FP/SP. Unlike pc_in_dummy_frame(), this function doesn't need to |
| adjust for DECR_PC_AFTER_BREAK. This is because it is only legal |
| to call this function after the PC has been adjusted. */ |
| |
| static struct dummy_frame * |
| find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp) |
| { |
| struct dummy_frame *dummyframe; |
| |
| for (dummyframe = dummy_frame_stack; dummyframe != NULL; |
| dummyframe = dummyframe->next) |
| { |
| /* Does the PC fall within the dummy frame's breakpoint |
| instruction. If not, discard this one. */ |
| if (!(pc >= dummyframe->call_lo && pc < dummyframe->call_hi)) |
| continue; |
| /* Does the FP match? */ |
| if (dummyframe->top != 0) |
| { |
| /* If the target architecture explicitly saved the |
| top-of-stack before the inferior function call, assume |
| that that same architecture will always pass in an FP |
| (frame base) value that eactly matches that saved TOS. |
| Don't check the saved SP and SP as they can lead to false |
| hits. */ |
| if (fp != dummyframe->top) |
| continue; |
| } |
| else |
| { |
| /* An older target that hasn't explicitly or implicitly |
| saved the dummy frame's top-of-stack. Try matching the |
| FP against the saved SP and FP. NOTE: If you're trying |
| to fix a problem with GDB not correctly finding a dummy |
| frame, check the comments that go with FRAME_ALIGN() and |
| UNWIND_DUMMY_ID(). */ |
| if (fp != dummyframe->fp && fp != dummyframe->sp) |
| continue; |
| } |
| /* The FP matches this dummy frame. */ |
| return dummyframe; |
| } |
| |
| return NULL; |
| } |
| |
| struct regcache * |
| deprecated_find_dummy_frame_regcache (CORE_ADDR pc, CORE_ADDR fp) |
| { |
| struct dummy_frame *dummy = find_dummy_frame (pc, fp); |
| if (dummy != NULL) |
| return dummy->regcache; |
| else |
| return NULL; |
| } |
| |
| char * |
| deprecated_generic_find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp) |
| { |
| struct regcache *regcache = deprecated_find_dummy_frame_regcache (pc, fp); |
| if (regcache == NULL) |
| return NULL; |
| return deprecated_grub_regcache_for_registers (regcache); |
| } |
| |
| /* Function: pc_in_call_dummy (pc, sp, fp) |
| |
| Return true if the PC falls in a dummy frame created by gdb for an |
| inferior call. The code below which allows DECR_PC_AFTER_BREAK is |
| for infrun.c, which may give the function a PC without that |
| subtracted out. */ |
| |
| int |
| generic_pc_in_call_dummy (CORE_ADDR pc, CORE_ADDR sp, CORE_ADDR fp) |
| { |
| return pc_in_dummy_frame (pc); |
| } |
| |
| /* Return non-zero if the PC falls in a dummy frame. |
| |
| The code below which allows DECR_PC_AFTER_BREAK is for infrun.c, |
| which may give the function a PC without that subtracted out. |
| |
| FIXME: cagney/2002-11-23: This is silly. Surely "infrun.c" can |
| figure out what the real PC (as in the resume address) is BEFORE |
| calling this function (Oh, and I'm not even sure that this function |
| is called with an decremented PC, the call to pc_in_call_dummy() in |
| that file is conditional on |
| !DEPRECATED_CALL_DUMMY_BREAKPOINT_OFFSET_P yet generic dummy |
| targets set DEPRECATED_CALL_DUMMY_BREAKPOINT_OFFSET. True?). */ |
| |
| int |
| pc_in_dummy_frame (CORE_ADDR pc) |
| { |
| struct dummy_frame *dummyframe; |
| for (dummyframe = dummy_frame_stack; |
| dummyframe != NULL; |
| dummyframe = dummyframe->next) |
| { |
| if ((pc >= dummyframe->call_lo) |
| && (pc < dummyframe->call_hi + DECR_PC_AFTER_BREAK)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* Function: read_register_dummy |
| Find a saved register from before GDB calls a function in the inferior */ |
| |
| CORE_ADDR |
| deprecated_read_register_dummy (CORE_ADDR pc, CORE_ADDR fp, int regno) |
| { |
| struct regcache *dummy_regs = deprecated_find_dummy_frame_regcache (pc, fp); |
| |
| if (dummy_regs) |
| { |
| /* NOTE: cagney/2002-08-12: Replaced a call to |
| regcache_raw_read_as_address() with a call to |
| regcache_cooked_read_unsigned(). The old, ...as_address |
| function was eventually calling extract_unsigned_integer (nee |
| extract_address) to unpack the registers value. The below is |
| doing an unsigned extract so that it is functionally |
| equivalent. The read needs to be cooked as, otherwise, it |
| will never correctly return the value of a register in the |
| [NUM_REGS .. NUM_REGS+NUM_PSEUDO_REGS) range. */ |
| ULONGEST val; |
| regcache_cooked_read_unsigned (dummy_regs, regno, &val); |
| return val; |
| } |
| else |
| return 0; |
| } |
| |
| /* Save all the registers on the dummy frame stack. Most ports save the |
| registers on the target stack. This results in lots of unnecessary memory |
| references, which are slow when debugging via a serial line. Instead, we |
| save all the registers internally, and never write them to the stack. The |
| registers get restored when the called function returns to the entry point, |
| where a breakpoint is laying in wait. */ |
| |
| void |
| generic_push_dummy_frame (void) |
| { |
| struct dummy_frame *dummy_frame; |
| CORE_ADDR fp = get_frame_base (get_current_frame ()); |
| |
| /* check to see if there are stale dummy frames, |
| perhaps left over from when a longjump took us out of a |
| function that was called by the debugger */ |
| |
| dummy_frame = dummy_frame_stack; |
| while (dummy_frame) |
| if (INNER_THAN (dummy_frame->fp, fp)) /* stale -- destroy! */ |
| { |
| dummy_frame_stack = dummy_frame->next; |
| regcache_xfree (dummy_frame->regcache); |
| xfree (dummy_frame); |
| dummy_frame = dummy_frame_stack; |
| } |
| else |
| dummy_frame = dummy_frame->next; |
| |
| dummy_frame = xmalloc (sizeof (struct dummy_frame)); |
| dummy_frame->regcache = regcache_xmalloc (current_gdbarch); |
| |
| dummy_frame->pc = read_pc (); |
| dummy_frame->sp = read_sp (); |
| dummy_frame->top = 0; |
| dummy_frame->fp = fp; |
| dummy_frame->id = get_frame_id (get_current_frame ()); |
| regcache_cpy (dummy_frame->regcache, current_regcache); |
| dummy_frame->next = dummy_frame_stack; |
| dummy_frame_stack = dummy_frame; |
| } |
| |
| void |
| generic_save_dummy_frame_tos (CORE_ADDR sp) |
| { |
| dummy_frame_stack->top = sp; |
| } |
| |
| /* Record the upper/lower bounds on the address of the call dummy. */ |
| |
| void |
| generic_save_call_dummy_addr (CORE_ADDR lo, CORE_ADDR hi) |
| { |
| dummy_frame_stack->call_lo = lo; |
| dummy_frame_stack->call_hi = hi; |
| } |
| |
| /* Restore the machine state from either the saved dummy stack or a |
| real stack frame. */ |
| |
| void |
| generic_pop_current_frame (void (*popper) (struct frame_info * frame)) |
| { |
| struct frame_info *frame = get_current_frame (); |
| if (get_frame_type (frame) == DUMMY_FRAME) |
| /* NOTE: cagney/2002-22-23: Does this ever occure? Surely a dummy |
| frame will have already been poped by the "infrun.c" code. */ |
| generic_pop_dummy_frame (); |
| else |
| (*popper) (frame); |
| } |
| |
| /* Discard the innermost dummy frame from the dummy frame stack |
| (passed in as a parameter). */ |
| |
| static void |
| discard_innermost_dummy (struct dummy_frame **stack) |
| { |
| struct dummy_frame *tbd = (*stack); |
| (*stack) = (*stack)->next; |
| regcache_xfree (tbd->regcache); |
| xfree (tbd); |
| } |
| |
| void |
| generic_pop_dummy_frame (void) |
| { |
| struct dummy_frame *dummy_frame = dummy_frame_stack; |
| |
| /* FIXME: what if the first frame isn't the right one, eg.. |
| because one call-by-hand function has done a longjmp into another one? */ |
| |
| if (!dummy_frame) |
| error ("Can't pop dummy frame!"); |
| regcache_cpy (current_regcache, dummy_frame->regcache); |
| flush_cached_frames (); |
| |
| discard_innermost_dummy (&dummy_frame_stack); |
| } |
| |
| /* Given a call-dummy dummy-frame, return the registers. Here the |
| register value is taken from the local copy of the register buffer. */ |
| |
| static void |
| dummy_frame_prev_register (struct frame_info *next_frame, |
| void **this_prologue_cache, |
| int regnum, int *optimized, |
| enum lval_type *lvalp, CORE_ADDR *addrp, |
| int *realnum, void *bufferp) |
| { |
| struct dummy_frame *dummy; |
| struct frame_id id; |
| |
| /* Call the ID method which, if at all possible, will set the |
| prologue cache. */ |
| dummy_frame_this_id (next_frame, this_prologue_cache, &id); |
| dummy = (*this_prologue_cache); |
| gdb_assert (dummy != NULL); |
| |
| /* Describe the register's location. Generic dummy frames always |
| have the register value in an ``expression''. */ |
| *optimized = 0; |
| *lvalp = not_lval; |
| *addrp = 0; |
| *realnum = -1; |
| |
| /* If needed, find and return the value of the register. */ |
| if (bufferp != NULL) |
| { |
| /* Return the actual value. */ |
| /* Use the regcache_cooked_read() method so that it, on the fly, |
| constructs either a raw or pseudo register from the raw |
| register cache. */ |
| regcache_cooked_read (dummy->regcache, regnum, bufferp); |
| } |
| } |
| |
| /* Assuming that THIS frame is a dummy (remember, the NEXT and not |
| THIS frame is passed in), return the ID of THIS frame. That ID is |
| determined by examining the NEXT frame's unwound registers using |
| the method unwind_dummy_id(). As a side effect, THIS dummy frame's |
| dummy cache is located and and saved in THIS_PROLOGUE_CACHE. */ |
| |
| static void |
| dummy_frame_this_id (struct frame_info *next_frame, |
| void **this_prologue_cache, |
| struct frame_id *this_id) |
| { |
| struct dummy_frame *dummy = (*this_prologue_cache); |
| if (dummy != NULL) |
| { |
| (*this_id) = dummy->id; |
| return; |
| } |
| /* When unwinding a normal frame, the stack structure is determined |
| by analyzing the frame's function's code (be it using brute force |
| prologue analysis, or the dwarf2 CFI). In the case of a dummy |
| frame, that simply isn't possible. The The PC is either the |
| program entry point, or some random address on the stack. Trying |
| to use that PC to apply standard frame ID unwind techniques is |
| just asking for trouble. */ |
| if (gdbarch_unwind_dummy_id_p (current_gdbarch)) |
| { |
| /* Use an architecture specific method to extract the prev's |
| dummy ID from the next frame. Note that this method uses |
| frame_register_unwind to obtain the register values needed to |
| determine the dummy frame's ID. */ |
| (*this_id) = gdbarch_unwind_dummy_id (current_gdbarch, next_frame); |
| } |
| else if (frame_relative_level (next_frame) < 0) |
| { |
| /* We're unwinding a sentinel frame, the PC of which is pointing |
| at a stack dummy. Fake up the dummy frame's ID using the |
| same sequence as is found a traditional unwinder. Once all |
| architectures supply the unwind_dummy_id method, this code |
| can go away. */ |
| (*this_id) = frame_id_build (deprecated_read_fp (), read_pc ()); |
| } |
| else if (legacy_frame_p (current_gdbarch) |
| && get_prev_frame (next_frame)) |
| { |
| /* Things are looking seriously grim! Assume that the legacy |
| get_prev_frame code has already created THIS frame and linked |
| it in to the frame chain (a pretty bold assumption), extract |
| the ID from THIS base / pc. */ |
| (*this_id) = frame_id_build (get_frame_base (get_prev_frame (next_frame)), |
| get_frame_pc (get_prev_frame (next_frame))); |
| } |
| else |
| { |
| /* Outch! We're not trying to find the innermost frame's ID yet |
| we're trying to unwind to a dummy. The architecture must |
| provide the unwind_dummy_id() method. Abandon the unwind |
| process but only after first warning the user. */ |
| internal_warning (__FILE__, __LINE__, |
| "Missing unwind_dummy_id architecture method"); |
| (*this_id) = null_frame_id; |
| return; |
| } |
| (*this_prologue_cache) = find_dummy_frame ((*this_id).code_addr, |
| (*this_id).stack_addr); |
| } |
| |
| static struct frame_unwind dummy_frame_unwind = |
| { |
| DUMMY_FRAME, |
| dummy_frame_this_id, |
| dummy_frame_prev_register |
| }; |
| |
| const struct frame_unwind * |
| dummy_frame_sniffer (struct frame_info *next_frame) |
| { |
| CORE_ADDR pc = frame_pc_unwind (next_frame); |
| if (DEPRECATED_PC_IN_CALL_DUMMY_P () |
| ? DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0) |
| : pc_in_dummy_frame (pc)) |
| return &dummy_frame_unwind; |
| else |
| return NULL; |
| } |
| |
| static void |
| fprint_dummy_frames (struct ui_file *file) |
| { |
| struct dummy_frame *s; |
| for (s = dummy_frame_stack; s != NULL; s = s->next) |
| { |
| gdb_print_host_address (s, file); |
| fprintf_unfiltered (file, ":"); |
| fprintf_unfiltered (file, " pc=0x%s", paddr (s->pc)); |
| fprintf_unfiltered (file, " fp=0x%s", paddr (s->fp)); |
| fprintf_unfiltered (file, " sp=0x%s", paddr (s->sp)); |
| fprintf_unfiltered (file, " top=0x%s", paddr (s->top)); |
| fprintf_unfiltered (file, " id="); |
| fprint_frame_id (file, s->id); |
| fprintf_unfiltered (file, " call_lo=0x%s", paddr (s->call_lo)); |
| fprintf_unfiltered (file, " call_hi=0x%s", paddr (s->call_hi)); |
| fprintf_unfiltered (file, "\n"); |
| } |
| } |
| |
| static void |
| maintenance_print_dummy_frames (char *args, int from_tty) |
| { |
| if (args == NULL) |
| fprint_dummy_frames (gdb_stdout); |
| else |
| { |
| struct ui_file *file = gdb_fopen (args, "w"); |
| if (file == NULL) |
| perror_with_name ("maintenance print dummy-frames"); |
| fprint_dummy_frames (file); |
| ui_file_delete (file); |
| } |
| } |
| |
| extern void _initialize_dummy_frame (void); |
| |
| void |
| _initialize_dummy_frame (void) |
| { |
| add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, |
| "Print the contents of the internal dummy-frame stack.", |
| &maintenanceprintlist); |
| |
| } |