331 lines
9.5 KiB
C
331 lines
9.5 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, 2008, 2009,
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2010 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 3 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, see <http://www.gnu.org/licenses/>. */
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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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#include "observer.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_dummy_id. */
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struct frame_id id;
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/* The caller's state prior to the call. */
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struct infcall_suspend_state *caller_state;
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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 gdbarch_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 (struct gdbarch *gdbarch, 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
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+ gdbarch_decr_pc_after_break (gdbarch)))
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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 the
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dummy-frame stack. */
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void
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dummy_frame_push (struct infcall_suspend_state *caller_state,
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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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dummy_frame = XZALLOC (struct dummy_frame);
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dummy_frame->caller_state = caller_state;
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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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/* Remove *DUMMY_PTR from the dummy frame stack. */
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static void
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remove_dummy_frame (struct dummy_frame **dummy_ptr)
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{
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struct dummy_frame *dummy = *dummy_ptr;
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*dummy_ptr = dummy->next;
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discard_infcall_suspend_state (dummy->caller_state);
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xfree (dummy);
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}
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/* Pop *DUMMY_PTR, restoring program state to that before the
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frame was created. */
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static void
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pop_dummy_frame (struct dummy_frame **dummy_ptr)
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{
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struct dummy_frame *dummy;
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restore_infcall_suspend_state ((*dummy_ptr)->caller_state);
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/* restore_infcall_control_state frees inf_state,
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all that remains is to pop *dummy_ptr */
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dummy = *dummy_ptr;
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*dummy_ptr = dummy->next;
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xfree (dummy);
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/* We've made right mess of GDB's local state, just discard
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everything. */
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reinit_frame_cache ();
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}
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/* Look up DUMMY_ID.
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Return NULL if not found. */
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static struct dummy_frame **
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lookup_dummy_frame (struct frame_id dummy_id)
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{
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struct dummy_frame **dp;
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for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next)
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{
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if (frame_id_eq ((*dp)->id, dummy_id))
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return dp;
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}
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return NULL;
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}
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/* Pop the dummy frame DUMMY_ID, restoring program state to that before the
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frame was created.
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On return reinit_frame_cache has been called.
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If the frame isn't found, flag an internal error.
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NOTE: This can only pop the one frame, even if it is in the middle of the
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stack, because the other frames may be for different threads, and there's
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currently no way to tell which stack frame is for which thread. */
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void
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dummy_frame_pop (struct frame_id dummy_id)
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{
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struct dummy_frame **dp;
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dp = lookup_dummy_frame (dummy_id);
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gdb_assert (dp != NULL);
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pop_dummy_frame (dp);
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}
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/* There may be stale dummy frames, perhaps left over from when a longjump took
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us out of a function that was called by the debugger. Clean them up at
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least once whenever we start a new inferior. */
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static void
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cleanup_dummy_frames (struct target_ops *target, int from_tty)
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{
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while (dummy_frame_stack != NULL)
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remove_dummy_frame (&dummy_frame_stack);
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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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static int
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dummy_frame_sniffer (const struct frame_unwind *self,
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struct frame_info *this_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 unless 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 this frame's
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dummy ID, assuming it is a dummy frame. */
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this_id = gdbarch_dummy_id (get_frame_arch (this_frame), this_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 = get_infcall_suspend_state_regcache
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(dummyframe->caller_state);
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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 struct value *
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dummy_frame_prev_register (struct frame_info *this_frame,
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void **this_prologue_cache,
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int regnum)
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{
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struct dummy_frame_cache *cache = (*this_prologue_cache);
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struct gdbarch *gdbarch = get_frame_arch (this_frame);
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struct value *reg_val;
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/* The dummy-frame sniffer always fills in the 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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reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
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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,
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value_contents_writeable (reg_val));
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return reg_val;
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}
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/* Assuming that THIS_FRAME is a dummy, return its ID. That ID is
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determined by examining the NEXT frame's unwound registers using
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the method 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 *this_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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const 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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NULL,
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dummy_frame_sniffer,
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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 cleanup *cleanups;
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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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cleanups = make_cleanup_ui_file_delete (file);
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fprint_dummy_frames (file);
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do_cleanups (cleanups);
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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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observer_attach_inferior_created (cleanup_dummy_frames);
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}
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