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/* Block-related functions for the GNU debugger, GDB.

   Copyright (C) 2003, 2007, 2008, 2009, 2010 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 "block.h"

#include "symtab.h"

#include "symfile.h"

#include "gdb_obstack.h"

#include "cp-support.h"

#include "addrmap.h"

/* This is used by struct block to store namespace-related info for

   C++ files, namely using declarations and the current namespace in

   scope.  */

struct block_namespace_info

{

  const char *scope;

  struct using_direct *using;

};

static void block_initialize_namespace (struct block *block,

                                        struct obstack *obstack);

/* Return Nonzero if block a is lexically nested within block b,

   or if a and b have the same pc range.

   Return zero otherwise. */

int

contained_in (const struct block *a, const struct block *b)

{

  if (!a || !b)

    return 0;

  do

    {

      if (a == b)

        return 1;

      /* If A is a function block, then A cannot be contained in B,

         except if A was inlined.  */

      if (BLOCK_FUNCTION (a) != NULL && !block_inlined_p (a))

        return 0;

      a = BLOCK_SUPERBLOCK (a);

    }

  while (a != NULL);

  return 0;

}

/* Return the symbol for the function which contains a specified

   lexical block, described by a struct block BL.  The return value

   will not be an inlined function; the containing function will be

   returned instead.  */

struct symbol *

block_linkage_function (const struct block *bl)

{

  while ((BLOCK_FUNCTION (bl) == NULL || block_inlined_p (bl))

         && BLOCK_SUPERBLOCK (bl) != NULL)

    bl = BLOCK_SUPERBLOCK (bl);

  return BLOCK_FUNCTION (bl);

}

/* Return one if BL represents an inlined function.  */

int

block_inlined_p (const struct block *bl)

{

  return BLOCK_FUNCTION (bl) != NULL && SYMBOL_INLINED (BLOCK_FUNCTION (bl));

}

/* Return the blockvector immediately containing the innermost lexical

   block containing the specified pc value and section, or 0 if there

   is none.  PBLOCK is a pointer to the block.  If PBLOCK is NULL, we

   don't pass this information back to the caller.  */

struct blockvector *

blockvector_for_pc_sect (CORE_ADDR pc, struct obj_section *section,

                         struct block **pblock, struct symtab *symtab)

{

  struct block *b;

  int bot, top, half;

  struct blockvector *bl;

  if (symtab == 0)               /* if no symtab specified by caller */

    {

      /* First search all symtabs for one whose file contains our pc */

      symtab = find_pc_sect_symtab (pc, section);

      if (symtab == 0)

        return 0;

    }

  bl = BLOCKVECTOR (symtab);

  /* Then search that symtab for the smallest block that wins.  */

  /* If we have an addrmap mapping code addresses to blocks, then use

     that.  */

  if (BLOCKVECTOR_MAP (bl))

    {

      b = addrmap_find (BLOCKVECTOR_MAP (bl), pc);

      if (b)

        {

          if (pblock)

            *pblock = b;

          return bl;

        }

      else

        return 0;

    }

  /* Otherwise, use binary search to find the last block that starts

     before PC.  */

  bot = 0;

  top = BLOCKVECTOR_NBLOCKS (bl);

  while (top - bot > 1)

    {

      half = (top - bot + 1) >> 1;

      b = BLOCKVECTOR_BLOCK (bl, bot + half);

      if (BLOCK_START (b) <= pc)

        bot += half;

      else

        top = bot + half;

    }

  /* Now search backward for a block that ends after PC.  */

  while (bot >= 0)

    {

      b = BLOCKVECTOR_BLOCK (bl, bot);

      if (BLOCK_END (b) > pc)

        {

          if (pblock)

            *pblock = b;

          return bl;

        }

      bot--;

    }

  return 0;

}

/* Return the blockvector immediately containing the innermost lexical block

   containing the specified pc value, or 0 if there is none.

   Backward compatibility, no section.  */

struct blockvector *

blockvector_for_pc (CORE_ADDR pc, struct block **pblock)

{

  return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),

                                  pblock, NULL);

}

/* Return the innermost lexical block containing the specified pc value

   in the specified section, or 0 if there is none.  */

struct block *

block_for_pc_sect (CORE_ADDR pc, struct obj_section *section)

{

  struct blockvector *bl;

  struct block *b;

  bl = blockvector_for_pc_sect (pc, section, &b, NULL);

  if (bl)

    return b;

  return 0;

}

/* Return the innermost lexical block containing the specified pc value,

   or 0 if there is none.  Backward compatibility, no section.  */

struct block *

block_for_pc (CORE_ADDR pc)

{

  return block_for_pc_sect (pc, find_pc_mapped_section (pc));

}

/* Now come some functions designed to deal with C++ namespace issues.

   The accessors are safe to use even in the non-C++ case.  */

/* This returns the namespace that BLOCK is enclosed in, or "" if it

   isn't enclosed in a namespace at all.  This travels the chain of

   superblocks looking for a scope, if necessary.  */

const char *

block_scope (const struct block *block)

{

  for (; block != NULL; block = BLOCK_SUPERBLOCK (block))

    {

      if (BLOCK_NAMESPACE (block) != NULL

          && BLOCK_NAMESPACE (block)->scope != NULL)

        return BLOCK_NAMESPACE (block)->scope;

    }

  return "";

}

/* Set BLOCK's scope member to SCOPE; if needed, allocate memory via

   OBSTACK.  (It won't make a copy of SCOPE, however, so that already

   has to be allocated correctly.)  */

void

block_set_scope (struct block *block, const char *scope,

                 struct obstack *obstack)

{

  block_initialize_namespace (block, obstack);

  BLOCK_NAMESPACE (block)->scope = scope;

}

/* This returns the using directives list associated with BLOCK, if

   any.  */

struct using_direct *

block_using (const struct block *block)

{

  if (block == NULL || BLOCK_NAMESPACE (block) == NULL)

    return NULL;

  else

    return BLOCK_NAMESPACE (block)->using;

}

/* Set BLOCK's using member to USING; if needed, allocate memory via

   OBSTACK.  (It won't make a copy of USING, however, so that already

   has to be allocated correctly.)  */

void

block_set_using (struct block *block,

                 struct using_direct *using,

                 struct obstack *obstack)

{

  block_initialize_namespace (block, obstack);

  BLOCK_NAMESPACE (block)->using = using;

}

/* If BLOCK_NAMESPACE (block) is NULL, allocate it via OBSTACK and

   ititialize its members to zero.  */

static void

block_initialize_namespace (struct block *block, struct obstack *obstack)

{

  if (BLOCK_NAMESPACE (block) == NULL)

    {

      BLOCK_NAMESPACE (block)

        = obstack_alloc (obstack, sizeof (struct block_namespace_info));

      BLOCK_NAMESPACE (block)->scope = NULL;

      BLOCK_NAMESPACE (block)->using = NULL;

    }

}

/* Return the static block associated to BLOCK.  Return NULL if block

   is NULL or if block is a global block.  */

const struct block *

block_static_block (const struct block *block)

{

  if (block == NULL || BLOCK_SUPERBLOCK (block) == NULL)

    return NULL;

  while (BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) != NULL)

    block = BLOCK_SUPERBLOCK (block);

  return block;

}

/* Return the static block associated to BLOCK.  Return NULL if block

   is NULL.  */

const struct block *

block_global_block (const struct block *block)

{

  if (block == NULL)

    return NULL;

  while (BLOCK_SUPERBLOCK (block) != NULL)

    block = BLOCK_SUPERBLOCK (block);

  return block;

}

/* Allocate a block on OBSTACK, and initialize its elements to

   zero/NULL.  This is useful for creating "dummy" blocks that don't

   correspond to actual source files.

   Warning: it sets the block's BLOCK_DICT to NULL, which isn't a

   valid value.  If you really don't want the block to have a

   dictionary, then you should subsequently set its BLOCK_DICT to

   dict_create_linear (obstack, NULL).  */

struct block *

allocate_block (struct obstack *obstack)

{

  struct block *bl = obstack_alloc (obstack, sizeof (struct block));

  BLOCK_START (bl) = 0;

  BLOCK_END (bl) = 0;

  BLOCK_FUNCTION (bl) = NULL;

  BLOCK_SUPERBLOCK (bl) = NULL;

  BLOCK_DICT (bl) = NULL;

  BLOCK_NAMESPACE (bl) = NULL;

  return bl;

}