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/* Get info from stack frames; convert between frames, blocks,

   functions and pc values.

   Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,

   1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "symtab.h"

#include "bfd.h"

#include "objfiles.h"

#include "frame.h"

#include "gdbcore.h"

#include "value.h"

#include "target.h"

#include "inferior.h"

#include "annotate.h"

#include "regcache.h"

#include "gdb_assert.h"

#include "dummy-frame.h"

#include "command.h"

#include "gdbcmd.h"

#include "block.h"

/* Prototypes for exported functions. */

void _initialize_blockframe (void);

/* Return the innermost lexical block in execution

   in a specified stack frame.  The frame address is assumed valid.

   If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code

   address we used to choose the block.  We use this to find a source

   line, to decide which macro definitions are in scope.

   The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's

   PC, and may not really be a valid PC at all.  For example, in the

   caller of a function declared to never return, the code at the

   return address will never be reached, so the call instruction may

   be the very last instruction in the block.  So the address we use

   to choose the block is actually one byte before the return address

   --- hopefully pointing us at the call instruction, or its delay

   slot instruction.  */

struct block *

get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)

{

  const CORE_ADDR pc = get_frame_address_in_block (frame);

  if (addr_in_block)

    *addr_in_block = pc;

  return block_for_pc (pc);

}

CORE_ADDR

get_pc_function_start (CORE_ADDR pc)

{

  struct block *bl;

  struct minimal_symbol *msymbol;

  bl = block_for_pc (pc);

  if (bl)

    {

      struct symbol *symbol = block_function (bl);

      if (symbol)

        {

          bl = SYMBOL_BLOCK_VALUE (symbol);

          return BLOCK_START (bl);

        }

    }

  msymbol = lookup_minimal_symbol_by_pc (pc);

  if (msymbol)

    {

      CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);

      if (find_pc_section (fstart))

        return fstart;

    }

  return 0;

}

/* Return the symbol for the function executing in frame FRAME.  */

struct symbol *

get_frame_function (struct frame_info *frame)

{

  struct block *bl = get_frame_block (frame, 0);

  if (bl == 0)

    return 0;

  return block_function (bl);

}

/* Return the function containing pc value PC in section SECTION.

   Returns 0 if function is not known.  */

struct symbol *

find_pc_sect_function (CORE_ADDR pc, struct bfd_section *section)

{

  struct block *b = block_for_pc_sect (pc, section);

  if (b == 0)

    return 0;

  return block_function (b);

}

/* Return the function containing pc value PC.

   Returns 0 if function is not known.  Backward compatibility, no section */

struct symbol *

find_pc_function (CORE_ADDR pc)

{

  return find_pc_sect_function (pc, find_pc_mapped_section (pc));

}

/* These variables are used to cache the most recent result

 * of find_pc_partial_function. */

static CORE_ADDR cache_pc_function_low = 0;

static CORE_ADDR cache_pc_function_high = 0;

static char *cache_pc_function_name = 0;

static struct bfd_section *cache_pc_function_section = NULL;

/* Clear cache, e.g. when symbol table is discarded. */

void

clear_pc_function_cache (void)

{

  cache_pc_function_low = 0;

  cache_pc_function_high = 0;

  cache_pc_function_name = (char *) 0;

  cache_pc_function_section = NULL;

}

/* Finds the "function" (text symbol) that is smaller than PC but

   greatest of all of the potential text symbols in SECTION.  Sets

   *NAME and/or *ADDRESS conditionally if that pointer is non-null.

   If ENDADDR is non-null, then set *ENDADDR to be the end of the

   function (exclusive), but passing ENDADDR as non-null means that

   the function might cause symbols to be read.  This function either

   succeeds or fails (not halfway succeeds).  If it succeeds, it sets

   *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.

   If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and

   returns 0.  */

/* Backward compatibility, no section argument.  */

int

find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,

                          CORE_ADDR *endaddr)

{

  struct bfd_section *section;

  struct partial_symtab *pst;

  struct symbol *f;

  struct minimal_symbol *msymbol;

  struct partial_symbol *psb;

  struct obj_section *osect;

  int i;

  CORE_ADDR mapped_pc;

  /* To ensure that the symbol returned belongs to the correct setion

     (and that the last [random] symbol from the previous section

     isn't returned) try to find the section containing PC.  First try

     the overlay code (which by default returns NULL); and second try

     the normal section code (which almost always succeeds).  */

  section = find_pc_overlay (pc);

  if (section == NULL)

    {

      struct obj_section *obj_section = find_pc_section (pc);

      if (obj_section == NULL)

        section = NULL;

      else

        section = obj_section->the_bfd_section;

    }

  mapped_pc = overlay_mapped_address (pc, section);

  if (mapped_pc >= cache_pc_function_low

      && mapped_pc < cache_pc_function_high

      && section == cache_pc_function_section)

    goto return_cached_value;

  msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);

  pst = find_pc_sect_psymtab (mapped_pc, section);

  if (pst)

    {

      /* Need to read the symbols to get a good value for the end address.  */

      if (endaddr != NULL && !pst->readin)

        {

          /* Need to get the terminal in case symbol-reading produces

             output.  */

          target_terminal_ours_for_output ();

          PSYMTAB_TO_SYMTAB (pst);

        }

      if (pst->readin)

        {

          /* Checking whether the msymbol has a larger value is for the

             "pathological" case mentioned in print_frame_info.  */

          f = find_pc_sect_function (mapped_pc, section);

          if (f != NULL

              && (msymbol == NULL

                  || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))

                      >= SYMBOL_VALUE_ADDRESS (msymbol))))

            {

              cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));

              cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));

              cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);

              cache_pc_function_section = section;

              goto return_cached_value;

            }

        }

      else

        {

          /* Now that static symbols go in the minimal symbol table, perhaps

             we could just ignore the partial symbols.  But at least for now

             we use the partial or minimal symbol, whichever is larger.  */

          psb = find_pc_sect_psymbol (pst, mapped_pc, section);

          if (psb

              && (msymbol == NULL ||

                  (SYMBOL_VALUE_ADDRESS (psb)

                   >= SYMBOL_VALUE_ADDRESS (msymbol))))

            {

              /* This case isn't being cached currently. */

              if (address)

                *address = SYMBOL_VALUE_ADDRESS (psb);

              if (name)

                *name = DEPRECATED_SYMBOL_NAME (psb);

              /* endaddr non-NULL can't happen here.  */

              return 1;

            }

        }

    }

  /* Not in the normal symbol tables, see if the pc is in a known section.

     If it's not, then give up.  This ensures that anything beyond the end

     of the text seg doesn't appear to be part of the last function in the

     text segment.  */

  osect = find_pc_sect_section (mapped_pc, section);

  if (!osect)

    msymbol = NULL;

  /* Must be in the minimal symbol table.  */

  if (msymbol == NULL)

    {

      /* No available symbol.  */

      if (name != NULL)

        *name = 0;

      if (address != NULL)

        *address = 0;

      if (endaddr != NULL)

        *endaddr = 0;

      return 0;

    }

  cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);

  cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);

  cache_pc_function_section = section;

  /* If the minimal symbol has a size, use it for the cache.

     Otherwise use the lesser of the next minimal symbol in the same

     section, or the end of the section, as the end of the

     function.  */

  if (MSYMBOL_SIZE (msymbol) != 0)

    cache_pc_function_high = cache_pc_function_low + MSYMBOL_SIZE (msymbol);

  else

    {

      /* Step over other symbols at this same address, and symbols in

         other sections, to find the next symbol in this section with

         a different address.  */

      for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)

        {

          if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)

              && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))

            break;

        }

      if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL

          && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)

        cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);

      else

        /* We got the start address from the last msymbol in the objfile.

           So the end address is the end of the section.  */

        cache_pc_function_high = osect->endaddr;

    }

 return_cached_value:

  if (address)

    {

      if (pc_in_unmapped_range (pc, section))

        *address = overlay_unmapped_address (cache_pc_function_low, section);

      else

        *address = cache_pc_function_low;

    }

  if (name)

    *name = cache_pc_function_name;

  if (endaddr)

    {

      if (pc_in_unmapped_range (pc, section))

        {

          /* Because the high address is actually beyond the end of

             the function (and therefore possibly beyond the end of

             the overlay), we must actually convert (high - 1) and

             then add one to that. */

          *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,

                                                   section);

        }

      else

        *endaddr = cache_pc_function_high;

    }

  return 1;

}

/* Return the innermost stack frame executing inside of BLOCK,

   or NULL if there is no such frame.  If BLOCK is NULL, just return NULL.  */

struct frame_info *

block_innermost_frame (struct block *block)

{

  struct frame_info *frame;

  CORE_ADDR start;

  CORE_ADDR end;

  CORE_ADDR calling_pc;

  if (block == NULL)

    return NULL;

  start = BLOCK_START (block);

  end = BLOCK_END (block);

  frame = get_current_frame ();

  while (frame != NULL)

    {

      calling_pc = get_frame_address_in_block (frame);

      if (calling_pc >= start && calling_pc < end)

        return frame;

      frame = get_prev_frame (frame);

    }

  return NULL;

}