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[/] [openrisc/] [trunk/] [gnu-old/] [gdb-6.8/] [gdb/] [dummy-frame.c] - Blame information for rev 840

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1 24 jeremybenn
/* 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
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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 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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/* 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 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 (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 (current_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 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 gdbarch *gdbarch = get_regcache_arch (caller_regcache);
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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 (gdbarch, 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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173
static void
174
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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{
249
  if (args == NULL)
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    fprint_dummy_frames (gdb_stdout);
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  else
252
    {
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      struct ui_file *file = gdb_fopen (args, "w");
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      if (file == NULL)
255
        perror_with_name (_("maintenance print dummy-frames"));
256
      fprint_dummy_frames (file);
257
      ui_file_delete (file);
258
    }
259
}
260
 
261
extern void _initialize_dummy_frame (void);
262
 
263
void
264
_initialize_dummy_frame (void)
265
{
266
  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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