| /* 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" |
| |
| /* 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 |
| SAVE_DUMMY_FRAME_TOS(). */ |
| if (fp != dummyframe->fp && fp != dummyframe->sp) |
| continue; |
| } |
| /* The FP matches this dummy frame. */ |
| return dummyframe; |
| } |
| |
| return NULL; |
| } |
| |
| struct dummy_frame * |
| cached_find_dummy_frame (struct frame_info *frame, void **cache) |
| { |
| if ((*cache) == NULL) |
| (*cache) = find_dummy_frame (get_frame_pc (frame), get_frame_base (frame)); |
| return (*cache); |
| } |
| |
| struct regcache * |
| generic_find_dummy_frame (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 = generic_find_dummy_frame (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 !CALL_DUMMY_BREAKPOINT_OFFSET_P yet |
| generic dummy targets set 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 = generic_find_dummy_frame (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 (via |
| 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); |
| } |
| |
| /* Function: dummy_frame_pop. Restore the machine state from a saved |
| dummy stack frame. */ |
| |
| static void |
| dummy_frame_pop (struct frame_info *fi, void **cache, |
| struct regcache *regcache) |
| { |
| struct dummy_frame *dummy = cached_find_dummy_frame (fi, cache); |
| |
| /* If it isn't, what are we even doing here? */ |
| gdb_assert (get_frame_type (fi) == DUMMY_FRAME); |
| |
| if (dummy == NULL) |
| error ("Can't pop dummy frame!"); |
| |
| /* Discard all dummy frames up-to but not including this one. */ |
| while (dummy_frame_stack != dummy) |
| discard_innermost_dummy (&dummy_frame_stack); |
| |
| /* Restore this one. */ |
| regcache_cpy (regcache, dummy->regcache); |
| flush_cached_frames (); |
| |
| /* Now discard it. */ |
| discard_innermost_dummy (&dummy_frame_stack); |
| |
| /* Note: target changed would be better. Registers, memory and |
| frame are all invalid. */ |
| flush_cached_frames (); |
| } |
| |
| 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); |
| } |
| |
| /* Function: fix_call_dummy |
| Stub function. Generic dummy frames typically do not need to fix |
| the frame being created */ |
| |
| void |
| generic_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs, |
| struct value **args, struct type *type, int gcc_p) |
| { |
| return; |
| } |
| |
| /* 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_register_unwind (struct frame_info *frame, void **cache, |
| int regnum, int *optimized, |
| enum lval_type *lvalp, CORE_ADDR *addrp, |
| int *realnum, void *bufferp) |
| { |
| struct dummy_frame *dummy = cached_find_dummy_frame (frame, 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 FRAME is a dummy, return the resume address for the |
| previous frame. */ |
| |
| static CORE_ADDR |
| dummy_frame_pc_unwind (struct frame_info *frame, |
| void **cache) |
| { |
| struct dummy_frame *dummy = cached_find_dummy_frame (frame, cache); |
| /* Oops! In a dummy-frame but can't find the stack dummy. Pretend |
| that the frame doesn't unwind. Should this function instead |
| return a has-no-caller indication? */ |
| if (dummy == NULL) |
| return 0; |
| return dummy->pc; |
| } |
| |
| |
| /* Assuming that FRAME is a dummy, return the ID of the calling frame |
| (the frame that the dummy has the saved state of). */ |
| |
| static void |
| dummy_frame_id_unwind (struct frame_info *frame, |
| void **cache, |
| struct frame_id *id) |
| { |
| struct dummy_frame *dummy = cached_find_dummy_frame (frame, cache); |
| /* Oops! In a dummy-frame but can't find the stack dummy. Pretend |
| that the frame doesn't unwind. Should this function instead |
| return a has-no-caller indication? */ |
| if (dummy == NULL) |
| (*id) = null_frame_id; |
| else |
| (*id) = dummy->id; |
| } |
| |
| static struct frame_unwind dummy_frame_unwind = |
| { |
| dummy_frame_pop, |
| dummy_frame_pc_unwind, |
| dummy_frame_id_unwind, |
| dummy_frame_register_unwind |
| }; |
| |
| const struct frame_unwind * |
| dummy_frame_p (CORE_ADDR pc) |
| { |
| 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; |
| } |