271 lines
8.2 KiB
C
271 lines
8.2 KiB
C
/* Code dealing with dummy stack frames, for GDB, the GNU debugger.
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Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
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1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007
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Free 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., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, 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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#include "gdb_string.h"
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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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/* This frame's ID. Must match the value returned by
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gdbarch_unwind_dummy_id. */
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struct frame_id id;
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/* The caller's regcache. */
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struct regcache *regcache;
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};
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static struct dummy_frame *dummy_frame_stack = NULL;
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/* Function: deprecated_pc_in_call_dummy (pc)
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Return non-zero if the PC falls in a dummy frame created by gdb for
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an inferior call. The code below which allows DECR_PC_AFTER_BREAK
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is for infrun.c, which may give the function a PC without that
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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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NOTE: cagney/2004-08-02: I'm pretty sure that, with the introduction of
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infrun.c:adjust_pc_after_break (thanks), this function is now
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always called with a correctly adjusted PC!
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NOTE: cagney/2004-08-02: Code should not need to call this. */
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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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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->id.code_addr)
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&& (pc <= dummyframe->id.code_addr + 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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/* Push the caller's state, along with the dummy frame info, onto a
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dummy-frame stack. */
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void
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dummy_frame_push (struct regcache *caller_regcache,
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const struct frame_id *dummy_id)
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{
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struct dummy_frame *dummy_frame;
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/* Check to see if there are stale dummy frames, perhaps left over
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from when a longjump took us out of a function that was called by
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the debugger. */
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dummy_frame = dummy_frame_stack;
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while (dummy_frame)
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/* FIXME: cagney/2004-08-02: Should just test IDs. */
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if (frame_id_inner (dummy_frame->id, (*dummy_id)))
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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 = XZALLOC (struct dummy_frame);
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dummy_frame->regcache = caller_regcache;
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dummy_frame->id = (*dummy_id);
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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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/* Return the dummy frame cache, it contains both the ID, and a
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pointer to the regcache. */
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struct dummy_frame_cache
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{
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struct frame_id this_id;
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struct regcache *prev_regcache;
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};
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int
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dummy_frame_sniffer (const struct frame_unwind *self,
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struct frame_info *next_frame,
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void **this_prologue_cache)
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{
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struct dummy_frame *dummyframe;
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struct frame_id this_id;
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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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/* Don't bother unles there is at least one dummy frame. */
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if (dummy_frame_stack != NULL)
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{
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/* Use an architecture specific method to extract the prev's
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dummy 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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this_id = gdbarch_unwind_dummy_id (get_frame_arch (next_frame),
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next_frame);
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/* Use that ID to find the corresponding cache entry. */
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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 (frame_id_eq (dummyframe->id, this_id))
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{
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struct dummy_frame_cache *cache;
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cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache);
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cache->prev_regcache = dummyframe->regcache;
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cache->this_id = this_id;
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(*this_prologue_cache) = cache;
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return 1;
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}
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}
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}
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return 0;
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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, gdb_byte *bufferp)
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{
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/* The dummy-frame sniffer always fills in the cache. */
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struct dummy_frame_cache *cache = (*this_prologue_cache);
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gdb_assert (cache != 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 (cache->prev_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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/* The dummy-frame sniffer always fills in the cache. */
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struct dummy_frame_cache *cache = (*this_prologue_cache);
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gdb_assert (cache != NULL);
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(*this_id) = cache->this_id;
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}
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static const struct frame_unwind dummy_frame_unwinder =
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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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NULL,
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dummy_frame_sniffer,
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};
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const struct frame_unwind *const dummy_frame_unwind = {
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&dummy_frame_unwinder
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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, " id=");
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fprint_frame_id (file, s->id);
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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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