320 lines
9.9 KiB
C
320 lines
9.9 KiB
C
/* Code dealing with dummy stack frames, for GDB, the GNU debugger.
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Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
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1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free
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Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "dummy-frame.h"
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#include "regcache.h"
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#include "frame.h"
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#include "inferior.h"
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#include "gdb_assert.h"
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#include "frame-unwind.h"
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#include "command.h"
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#include "gdbcmd.h"
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static void dummy_frame_this_id (struct frame_info *next_frame,
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void **this_prologue_cache,
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struct frame_id *this_id);
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static int pc_in_dummy_frame (CORE_ADDR pc);
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/* Dummy frame. This saves the processor state just prior to setting
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up the inferior function call. Older targets save the registers
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on the target stack (but that really slows down function calls). */
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struct dummy_frame
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{
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struct dummy_frame *next;
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/* These values belong to the caller (the previous frame, the frame
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that this unwinds back to). */
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CORE_ADDR pc;
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CORE_ADDR top;
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struct frame_id id;
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struct regcache *regcache;
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/* Address range of the call dummy code. Look for PC in the range
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[LO..HI) (after allowing for DECR_PC_AFTER_BREAK). */
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CORE_ADDR call_lo;
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CORE_ADDR call_hi;
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};
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static struct dummy_frame *dummy_frame_stack = NULL;
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/* Function: find_dummy_frame(pc, fp, sp)
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Search the stack of dummy frames for one matching the given PC and
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FP/SP. Unlike pc_in_dummy_frame(), this function doesn't need to
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adjust for DECR_PC_AFTER_BREAK. This is because it is only legal
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to call this function after the PC has been adjusted. */
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static struct dummy_frame *
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find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp)
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{
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struct dummy_frame *dummyframe;
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for (dummyframe = dummy_frame_stack; dummyframe != NULL;
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dummyframe = dummyframe->next)
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{
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/* Does the PC fall within the dummy frame's breakpoint
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instruction. If not, discard this one. */
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if (!(pc >= dummyframe->call_lo && pc < dummyframe->call_hi))
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continue;
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/* Does the FP match? */
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/* "infcall.c" explicitly saved the top-of-stack before the
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inferior function call, assume unwind_dummy_id() returns that
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same stack value. */
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if (fp != dummyframe->top)
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continue;
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/* The FP matches this dummy frame. */
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return dummyframe;
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}
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return NULL;
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}
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/* Function: pc_in_call_dummy (pc)
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Return true if the PC falls in a dummy frame created by gdb for an
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inferior call. The code below which allows DECR_PC_AFTER_BREAK is
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for infrun.c, which may give the function a PC without that
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subtracted out. */
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int
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deprecated_pc_in_call_dummy (CORE_ADDR pc)
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{
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return pc_in_dummy_frame (pc);
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}
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/* Return non-zero if the PC falls in a dummy frame.
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The code below which allows DECR_PC_AFTER_BREAK is for infrun.c,
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which may give the function a PC without that subtracted out.
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FIXME: cagney/2002-11-23: This is silly. Surely "infrun.c" can
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figure out what the real PC (as in the resume address) is BEFORE
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calling this function. */
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static int
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pc_in_dummy_frame (CORE_ADDR pc)
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{
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struct dummy_frame *dummyframe;
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for (dummyframe = dummy_frame_stack;
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dummyframe != NULL;
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dummyframe = dummyframe->next)
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{
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if ((pc >= dummyframe->call_lo)
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&& (pc < dummyframe->call_hi + DECR_PC_AFTER_BREAK))
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return 1;
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}
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return 0;
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}
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/* Save all the registers on the dummy frame stack. Most ports save the
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registers on the target stack. This results in lots of unnecessary memory
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references, which are slow when debugging via a serial line. Instead, we
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save all the registers internally, and never write them to the stack. The
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registers get restored when the called function returns to the entry point,
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where a breakpoint is laying in wait. */
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void
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generic_push_dummy_frame (void)
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{
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struct dummy_frame *dummy_frame;
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CORE_ADDR fp = get_frame_base (get_current_frame ());
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/* check to see if there are stale dummy frames,
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perhaps left over from when a longjump took us out of a
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function that was called by the debugger */
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dummy_frame = dummy_frame_stack;
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while (dummy_frame)
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if (gdbarch_inner_than (current_gdbarch, dummy_frame->top, fp))
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/* stale -- destroy! */
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{
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dummy_frame_stack = dummy_frame->next;
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regcache_xfree (dummy_frame->regcache);
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xfree (dummy_frame);
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dummy_frame = dummy_frame_stack;
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}
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else
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dummy_frame = dummy_frame->next;
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dummy_frame = xmalloc (sizeof (struct dummy_frame));
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dummy_frame->regcache = regcache_xmalloc (current_gdbarch);
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dummy_frame->pc = read_pc ();
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dummy_frame->top = 0;
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dummy_frame->id = get_frame_id (get_current_frame ());
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regcache_cpy (dummy_frame->regcache, current_regcache);
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dummy_frame->next = dummy_frame_stack;
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dummy_frame_stack = dummy_frame;
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}
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void
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generic_save_dummy_frame_tos (CORE_ADDR sp)
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{
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dummy_frame_stack->top = sp;
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}
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/* Record the upper/lower bounds on the address of the call dummy. */
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void
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generic_save_call_dummy_addr (CORE_ADDR lo, CORE_ADDR hi)
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{
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dummy_frame_stack->call_lo = lo;
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dummy_frame_stack->call_hi = hi;
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}
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/* Given a call-dummy dummy-frame, return the registers. Here the
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register value is taken from the local copy of the register buffer. */
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static void
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dummy_frame_prev_register (struct frame_info *next_frame,
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void **this_prologue_cache,
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int regnum, int *optimized,
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enum lval_type *lvalp, CORE_ADDR *addrp,
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int *realnum, void *bufferp)
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{
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struct dummy_frame *dummy;
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struct frame_id id;
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/* Call the ID method which, if at all possible, will set the
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prologue cache. */
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dummy_frame_this_id (next_frame, this_prologue_cache, &id);
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dummy = (*this_prologue_cache);
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gdb_assert (dummy != NULL);
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/* Describe the register's location. Generic dummy frames always
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have the register value in an ``expression''. */
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*optimized = 0;
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*lvalp = not_lval;
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*addrp = 0;
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*realnum = -1;
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/* If needed, find and return the value of the register. */
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if (bufferp != NULL)
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{
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/* Return the actual value. */
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/* Use the regcache_cooked_read() method so that it, on the fly,
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constructs either a raw or pseudo register from the raw
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register cache. */
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regcache_cooked_read (dummy->regcache, regnum, bufferp);
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}
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}
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/* Assuming that THIS frame is a dummy (remember, the NEXT and not
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THIS frame is passed in), return the ID of THIS frame. That ID is
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determined by examining the NEXT frame's unwound registers using
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the method unwind_dummy_id(). As a side effect, THIS dummy frame's
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dummy cache is located and and saved in THIS_PROLOGUE_CACHE. */
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static void
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dummy_frame_this_id (struct frame_info *next_frame,
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void **this_prologue_cache,
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struct frame_id *this_id)
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{
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struct dummy_frame *dummy = (*this_prologue_cache);
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if (dummy != NULL)
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{
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(*this_id) = dummy->id;
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return;
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}
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/* When unwinding a normal frame, the stack structure is determined
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by analyzing the frame's function's code (be it using brute force
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prologue analysis, or the dwarf2 CFI). In the case of a dummy
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frame, that simply isn't possible. The PC is either the program
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entry point, or some random address on the stack. Trying to use
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that PC to apply standard frame ID unwind techniques is just
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asking for trouble. */
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/* Use an architecture specific method to extract the prev's dummy
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ID from the next frame. Note that this method uses
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frame_register_unwind to obtain the register values needed to
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determine the dummy frame's ID. */
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gdb_assert (gdbarch_unwind_dummy_id_p (current_gdbarch));
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(*this_id) = gdbarch_unwind_dummy_id (current_gdbarch, next_frame);
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(*this_prologue_cache) = find_dummy_frame ((*this_id).code_addr,
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(*this_id).stack_addr);
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}
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static struct frame_unwind dummy_frame_unwind =
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{
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DUMMY_FRAME,
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dummy_frame_this_id,
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dummy_frame_prev_register
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};
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const struct frame_unwind *
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dummy_frame_sniffer (struct frame_info *next_frame)
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{
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CORE_ADDR pc = frame_pc_unwind (next_frame);
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if (pc_in_dummy_frame (pc))
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return &dummy_frame_unwind;
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else
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return NULL;
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}
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static void
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fprint_dummy_frames (struct ui_file *file)
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{
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struct dummy_frame *s;
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for (s = dummy_frame_stack; s != NULL; s = s->next)
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{
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gdb_print_host_address (s, file);
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fprintf_unfiltered (file, ":");
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fprintf_unfiltered (file, " pc=0x%s", paddr (s->pc));
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fprintf_unfiltered (file, " top=0x%s", paddr (s->top));
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fprintf_unfiltered (file, " id=");
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fprint_frame_id (file, s->id);
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fprintf_unfiltered (file, " call_lo=0x%s", paddr (s->call_lo));
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fprintf_unfiltered (file, " call_hi=0x%s", paddr (s->call_hi));
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fprintf_unfiltered (file, "\n");
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}
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}
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static void
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maintenance_print_dummy_frames (char *args, int from_tty)
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{
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if (args == NULL)
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fprint_dummy_frames (gdb_stdout);
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else
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{
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struct ui_file *file = gdb_fopen (args, "w");
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if (file == NULL)
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perror_with_name ("maintenance print dummy-frames");
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fprint_dummy_frames (file);
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ui_file_delete (file);
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}
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}
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extern void _initialize_dummy_frame (void);
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void
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_initialize_dummy_frame (void)
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{
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add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames,
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"Print the contents of the internal dummy-frame stack.",
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&maintenanceprintlist);
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}
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