Add assert in prepare_for_building

[deliverable/binutils-gdb.git] / gdb / buildsym.c

/* Support routines for building symbol tables in GDB's internal format.
   Copyright (C) 1986-2018 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/>.  */

/* This module provides subroutines used for creating and adding to
   the symbol table.  These routines are called from various symbol-
   file-reading routines.

   Routines to support specific debugging information formats (stabs,
   DWARF, etc) belong somewhere else.

   The basic way this module is used is as follows:

   buildsym_init ();
   scoped_free_pendings free_pending;
   cust = start_symtab (...);
   ... read debug info ...
   cust = end_symtab (...);

   The compunit symtab pointer ("cust") is returned from both start_symtab
   and end_symtab to simplify the debug info readers.

   There are minor variations on this, e.g., dwarf2read.c splits end_symtab
   into two calls: end_symtab_get_static_block, end_symtab_from_static_block,
   but all debug info readers follow this basic flow.

   Reading DWARF Type Units is another variation:

   buildsym_init ();
   scoped_free_pendings free_pending;
   cust = start_symtab (...);
   ... read debug info ...
   cust = end_expandable_symtab (...);

   And then reading subsequent Type Units within the containing "Comp Unit"
   will use a second flow:

   buildsym_init ();
   scoped_free_pendings free_pending;
   cust = restart_symtab (...);
   ... read debug info ...
   cust = augment_type_symtab (...);

   dbxread.c and xcoffread.c use another variation:

   buildsym_init ();
   scoped_free_pendings free_pending;
   cust = start_symtab (...);
   ... read debug info ...
   cust = end_symtab (...);
   ... start_symtab + read + end_symtab repeated ...
*/

#include "defs.h"
#include "bfd.h"
#include "gdb_obstack.h"
#include "symtab.h"
#include "symfile.h"
#include "objfiles.h"
#include "gdbtypes.h"
#include "complaints.h"
#include "expression.h"         /* For "enum exp_opcode" used by...  */
#include "bcache.h"
#include "filenames.h"          /* For DOSish file names.  */
#include "macrotab.h"
#include "demangle.h"           /* Needed by SYMBOL_INIT_DEMANGLED_NAME.  */
#include "block.h"
#include "cp-support.h"
#include "dictionary.h"
#include "addrmap.h"
#include <algorithm>

/* Ask buildsym.h to define the vars it normally declares `extern'.  */
#define EXTERN
/**/
#include "buildsym.h"           /* Our own declarations.  */
#undef  EXTERN

/* For cleanup_undefined_stabs_types and finish_global_stabs (somewhat
   questionable--see comment where we call them).  */

#include "stabsread.h"

/* Buildsym's counterpart to struct compunit_symtab.
   TODO(dje): Move all related global state into here.  */

struct buildsym_compunit
{
  /* Start recording information about a primary source file (IOW, not an
     included source file).
     COMP_DIR is the directory in which the compilation unit was compiled
     (or NULL if not known).  */

  buildsym_compunit (struct objfile *objfile_, const char *comp_dir_,
                     enum language language_)
    : objfile (objfile_),
      comp_dir (comp_dir_ == nullptr ? nullptr : xstrdup (comp_dir_)),
      language (language_)
  {
  }

  ~buildsym_compunit ()
  {
    struct subfile *subfile, *nextsub;

    for (subfile = subfiles;
         subfile != NULL;
         subfile = nextsub)
      {
        nextsub = subfile->next;
        xfree (subfile->name);
        xfree (subfile->line_vector);
        xfree (subfile);
      }
  }

  /* The objfile we're reading debug info from.  */
  struct objfile *objfile;

  /* List of subfiles (source files).
     Files are added to the front of the list.
     This is important mostly for the language determination hacks we use,
     which iterate over previously added files.  */
  struct subfile *subfiles = nullptr;

  /* The subfile of the main source file.  */
  struct subfile *main_subfile = nullptr;

  /* E.g., DW_AT_comp_dir if DWARF.  Space for this is malloc'd.  */
  gdb::unique_xmalloc_ptr<char> comp_dir;

  /* Space for this is not malloc'd, and is assumed to have at least
     the same lifetime as objfile.  */
  const char *producer = nullptr;

  /* Space for this is not malloc'd, and is assumed to have at least
     the same lifetime as objfile.  */
  const char *debugformat = nullptr;

  /* The compunit we are building.  */
  struct compunit_symtab *compunit_symtab = nullptr;

  /* Language of this compunit_symtab.  */
  enum language language;
};

/* The work-in-progress of the compunit we are building.
   This is created first, before any subfiles by start_symtab.  */

static struct buildsym_compunit *buildsym_compunit;

/* List of free `struct pending' structures for reuse.  */

static struct pending *free_pendings;

/* Non-zero if symtab has line number info.  This prevents an
   otherwise empty symtab from being tossed.  */

static int have_line_numbers;

/* The mutable address map for the compilation unit whose symbols
   we're currently reading.  The symtabs' shared blockvector will
   point to a fixed copy of this.  */
static struct addrmap *pending_addrmap;

/* The obstack on which we allocate pending_addrmap.
   If pending_addrmap is NULL, this is uninitialized; otherwise, it is
   initialized (and holds pending_addrmap).  */
static struct obstack pending_addrmap_obstack;

/* Non-zero if we recorded any ranges in the addrmap that are
   different from those in the blockvector already.  We set this to
   zero when we start processing a symfile, and if it's still zero at
   the end, then we just toss the addrmap.  */
static int pending_addrmap_interesting;

/* An obstack used for allocating pending blocks.  */

static struct obstack pending_block_obstack;

/* List of blocks already made (lexical contexts already closed).
   This is used at the end to make the blockvector.  */

struct pending_block
  {
    struct pending_block *next;
    struct block *block;
  };

/* Pointer to the head of a linked list of symbol blocks which have
   already been finalized (lexical contexts already closed) and which
   are just waiting to be built into a blockvector when finalizing the
   associated symtab.  */

static struct pending_block *pending_blocks;

struct subfile_stack
  {
    struct subfile_stack *next;
    char *name;
  };

static struct subfile_stack *subfile_stack;

/* The macro table for the compilation unit whose symbols we're
   currently reading.  */
static struct macro_table *pending_macros;

static void free_buildsym_compunit (void);

static int compare_line_numbers (const void *ln1p, const void *ln2p);

static void record_pending_block (struct objfile *objfile,
                                  struct block *block,
                                  struct pending_block *opblock);

/* Initial sizes of data structures.  These are realloc'd larger if
   needed, and realloc'd down to the size actually used, when
   completed.  */

#define INITIAL_CONTEXT_STACK_SIZE      10
#define INITIAL_LINE_VECTOR_LENGTH      1000
\f

/* Maintain the lists of symbols and blocks.  */

/* Add a symbol to one of the lists of symbols.  */

void
add_symbol_to_list (struct symbol *symbol, struct pending **listhead)
{
  struct pending *link;

  /* If this is an alias for another symbol, don't add it.  */
  if (symbol->ginfo.name && symbol->ginfo.name[0] == '#')
    return;

  /* We keep PENDINGSIZE symbols in each link of the list.  If we
     don't have a link with room in it, add a new link.  */
  if (*listhead == NULL || (*listhead)->nsyms == PENDINGSIZE)
    {
      if (free_pendings)
        {
          link = free_pendings;
          free_pendings = link->next;
        }
      else
        {
          link = XNEW (struct pending);
        }

      link->next = *listhead;
      *listhead = link;
      link->nsyms = 0;
    }

  (*listhead)->symbol[(*listhead)->nsyms++] = symbol;
}

/* Find a symbol named NAME on a LIST.  NAME need not be
   '\0'-terminated; LENGTH is the length of the name.  */

struct symbol *
find_symbol_in_list (struct pending *list, char *name, int length)
{
  int j;
  const char *pp;

  while (list != NULL)
    {
      for (j = list->nsyms; --j >= 0;)
        {
          pp = SYMBOL_LINKAGE_NAME (list->symbol[j]);
          if (*pp == *name && strncmp (pp, name, length) == 0
              && pp[length] == '\0')
            {
              return (list->symbol[j]);
            }
        }
      list = list->next;
    }
  return (NULL);
}

/* At end of reading syms, or in case of quit, ensure everything
   associated with building symtabs is freed.

   N.B. This is *not* intended to be used when building psymtabs.  Some debug
   info readers call this anyway, which is harmless if confusing.  */

scoped_free_pendings::~scoped_free_pendings ()
{
  struct pending *next, *next1;

  for (next = free_pendings; next; next = next1)
    {
      next1 = next->next;
      xfree ((void *) next);
    }
  free_pendings = NULL;

  free_pending_blocks ();

  for (next = file_symbols; next != NULL; next = next1)
    {
      next1 = next->next;
      xfree ((void *) next);
    }
  file_symbols = NULL;

  for (next = global_symbols; next != NULL; next = next1)
    {
      next1 = next->next;
      xfree ((void *) next);
    }
  global_symbols = NULL;

  if (pending_macros)
    free_macro_table (pending_macros);
  pending_macros = NULL;

  if (pending_addrmap)
    obstack_free (&pending_addrmap_obstack, NULL);
  pending_addrmap = NULL;

  free_buildsym_compunit ();
}

/* This function is called to discard any pending blocks.  */

void
free_pending_blocks (void)
{
  if (pending_blocks != NULL)
    {
      obstack_free (&pending_block_obstack, NULL);
      pending_blocks = NULL;
    }
}

/* Take one of the lists of symbols and make a block from it.  Keep
   the order the symbols have in the list (reversed from the input
   file).  Put the block on the list of pending blocks.  */

static struct block *
finish_block_internal (struct symbol *symbol,
                       struct pending **listhead,
                       struct pending_block *old_blocks,
                       const struct dynamic_prop *static_link,
                       CORE_ADDR start, CORE_ADDR end,
                       int is_global, int expandable)
{
  struct objfile *objfile = buildsym_compunit->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  struct pending *next, *next1;
  struct block *block;
  struct pending_block *pblock;
  struct pending_block *opblock;

  block = (is_global
           ? allocate_global_block (&objfile->objfile_obstack)
           : allocate_block (&objfile->objfile_obstack));

  if (symbol)
    {
      BLOCK_DICT (block)
        = dict_create_linear (&objfile->objfile_obstack,
                              buildsym_compunit->language, *listhead);
    }
  else
    {
      if (expandable)
        {
          BLOCK_DICT (block)
            = dict_create_hashed_expandable (buildsym_compunit->language);
          dict_add_pending (BLOCK_DICT (block), *listhead);
        }
      else
        {
          BLOCK_DICT (block) =
            dict_create_hashed (&objfile->objfile_obstack,
                                buildsym_compunit->language, *listhead);
        }
    }

  BLOCK_START (block) = start;
  BLOCK_END (block) = end;

  /* Put the block in as the value of the symbol that names it.  */

  if (symbol)
    {
      struct type *ftype = SYMBOL_TYPE (symbol);
      struct dict_iterator iter;
      SYMBOL_BLOCK_VALUE (symbol) = block;
      BLOCK_FUNCTION (block) = symbol;

      if (TYPE_NFIELDS (ftype) <= 0)
        {
          /* No parameter type information is recorded with the
             function's type.  Set that from the type of the
             parameter symbols.  */
          int nparams = 0, iparams;
          struct symbol *sym;

          /* Here we want to directly access the dictionary, because
             we haven't fully initialized the block yet.  */
          ALL_DICT_SYMBOLS (BLOCK_DICT (block), iter, sym)
            {
              if (SYMBOL_IS_ARGUMENT (sym))
                nparams++;
            }
          if (nparams > 0)
            {
              TYPE_NFIELDS (ftype) = nparams;
              TYPE_FIELDS (ftype) = (struct field *)
                TYPE_ALLOC (ftype, nparams * sizeof (struct field));

              iparams = 0;
              /* Here we want to directly access the dictionary, because
                 we haven't fully initialized the block yet.  */
              ALL_DICT_SYMBOLS (BLOCK_DICT (block), iter, sym)
                {
                  if (iparams == nparams)
                    break;

                  if (SYMBOL_IS_ARGUMENT (sym))
                    {
                      TYPE_FIELD_TYPE (ftype, iparams) = SYMBOL_TYPE (sym);
                      TYPE_FIELD_ARTIFICIAL (ftype, iparams) = 0;
                      iparams++;
                    }
                }
            }
        }
    }
  else
    {
      BLOCK_FUNCTION (block) = NULL;
    }

  if (static_link != NULL)
    objfile_register_static_link (objfile, block, static_link);

  /* Now "free" the links of the list, and empty the list.  */

  for (next = *listhead; next; next = next1)
    {
      next1 = next->next;
      next->next = free_pendings;
      free_pendings = next;
    }
  *listhead = NULL;

  /* Check to be sure that the blocks have an end address that is
     greater than starting address.  */

  if (BLOCK_END (block) < BLOCK_START (block))
    {
      if (symbol)
        {
          complaint (_("block end address less than block "
                       "start address in %s (patched it)"),
                     SYMBOL_PRINT_NAME (symbol));
        }
      else
        {
          complaint (_("block end address %s less than block "
                       "start address %s (patched it)"),
                     paddress (gdbarch, BLOCK_END (block)),
                     paddress (gdbarch, BLOCK_START (block)));
        }
      /* Better than nothing.  */
      BLOCK_END (block) = BLOCK_START (block);
    }

  /* Install this block as the superblock of all blocks made since the
     start of this scope that don't have superblocks yet.  */

  opblock = NULL;
  for (pblock = pending_blocks; 
       pblock && pblock != old_blocks; 
       pblock = pblock->next)
    {
      if (BLOCK_SUPERBLOCK (pblock->block) == NULL)
        {
          /* Check to be sure the blocks are nested as we receive
             them.  If the compiler/assembler/linker work, this just
             burns a small amount of time.

             Skip blocks which correspond to a function; they're not
             physically nested inside this other blocks, only
             lexically nested.  */
          if (BLOCK_FUNCTION (pblock->block) == NULL
              && (BLOCK_START (pblock->block) < BLOCK_START (block)
                  || BLOCK_END (pblock->block) > BLOCK_END (block)))
            {
              if (symbol)
                {
                  complaint (_("inner block not inside outer block in %s"),
                             SYMBOL_PRINT_NAME (symbol));
                }
              else
                {
                  complaint (_("inner block (%s-%s) not "
                               "inside outer block (%s-%s)"),
                             paddress (gdbarch, BLOCK_START (pblock->block)),
                             paddress (gdbarch, BLOCK_END (pblock->block)),
                             paddress (gdbarch, BLOCK_START (block)),
                             paddress (gdbarch, BLOCK_END (block)));
                }
              if (BLOCK_START (pblock->block) < BLOCK_START (block))
                BLOCK_START (pblock->block) = BLOCK_START (block);
              if (BLOCK_END (pblock->block) > BLOCK_END (block))
                BLOCK_END (pblock->block) = BLOCK_END (block);
            }
          BLOCK_SUPERBLOCK (pblock->block) = block;
        }
      opblock = pblock;
    }

  block_set_using (block,
                   (is_global
                    ? global_using_directives
                    : local_using_directives),
                   &objfile->objfile_obstack);
  if (is_global)
    global_using_directives = NULL;
  else
    local_using_directives = NULL;

  record_pending_block (objfile, block, opblock);

  return block;
}

struct block *
finish_block (struct symbol *symbol,
              struct pending **listhead,
              struct pending_block *old_blocks,
              const struct dynamic_prop *static_link,
              CORE_ADDR start, CORE_ADDR end)
{
  return finish_block_internal (symbol, listhead, old_blocks, static_link,
                                start, end, 0, 0);
}

/* Record BLOCK on the list of all blocks in the file.  Put it after
   OPBLOCK, or at the beginning if opblock is NULL.  This puts the
   block in the list after all its subblocks.

   Allocate the pending block struct in the objfile_obstack to save
   time.  This wastes a little space.  FIXME: Is it worth it?  */

static void
record_pending_block (struct objfile *objfile, struct block *block,
                      struct pending_block *opblock)
{
  struct pending_block *pblock;

  if (pending_blocks == NULL)
    obstack_init (&pending_block_obstack);

  pblock = XOBNEW (&pending_block_obstack, struct pending_block);
  pblock->block = block;
  if (opblock)
    {
      pblock->next = opblock->next;
      opblock->next = pblock;
    }
  else
    {
      pblock->next = pending_blocks;
      pending_blocks = pblock;
    }
}


/* Record that the range of addresses from START to END_INCLUSIVE
   (inclusive, like it says) belongs to BLOCK.  BLOCK's start and end
   addresses must be set already.  You must apply this function to all
   BLOCK's children before applying it to BLOCK.

   If a call to this function complicates the picture beyond that
   already provided by BLOCK_START and BLOCK_END, then we create an
   address map for the block.  */
void
record_block_range (struct block *block,
                    CORE_ADDR start, CORE_ADDR end_inclusive)
{
  /* If this is any different from the range recorded in the block's
     own BLOCK_START and BLOCK_END, then note that the address map has
     become interesting.  Note that even if this block doesn't have
     any "interesting" ranges, some later block might, so we still
     need to record this block in the addrmap.  */
  if (start != BLOCK_START (block)
      || end_inclusive + 1 != BLOCK_END (block))
    pending_addrmap_interesting = 1;

  if (! pending_addrmap)
    {
      obstack_init (&pending_addrmap_obstack);
      pending_addrmap = addrmap_create_mutable (&pending_addrmap_obstack);
    }

  addrmap_set_empty (pending_addrmap, start, end_inclusive, block);
}

static struct blockvector *
make_blockvector (void)
{
  struct objfile *objfile = buildsym_compunit->objfile;
  struct pending_block *next;
  struct blockvector *blockvector;
  int i;

  /* Count the length of the list of blocks.  */

  for (next = pending_blocks, i = 0; next; next = next->next, i++)
    {;
    }

  blockvector = (struct blockvector *)
    obstack_alloc (&objfile->objfile_obstack,
                   (sizeof (struct blockvector)
                    + (i - 1) * sizeof (struct block *)));

  /* Copy the blocks into the blockvector.  This is done in reverse
     order, which happens to put the blocks into the proper order
     (ascending starting address).  finish_block has hair to insert
     each block into the list after its subblocks in order to make
     sure this is true.  */

  BLOCKVECTOR_NBLOCKS (blockvector) = i;
  for (next = pending_blocks; next; next = next->next)
    {
      BLOCKVECTOR_BLOCK (blockvector, --i) = next->block;
    }

  free_pending_blocks ();

  /* If we needed an address map for this symtab, record it in the
     blockvector.  */
  if (pending_addrmap && pending_addrmap_interesting)
    BLOCKVECTOR_MAP (blockvector)
      = addrmap_create_fixed (pending_addrmap, &objfile->objfile_obstack);
  else
    BLOCKVECTOR_MAP (blockvector) = 0;

  /* Some compilers output blocks in the wrong order, but we depend on
     their being in the right order so we can binary search.  Check the
     order and moan about it.
     Note: Remember that the first two blocks are the global and static
     blocks.  We could special case that fact and begin checking at block 2.
     To avoid making that assumption we do not.  */
  if (BLOCKVECTOR_NBLOCKS (blockvector) > 1)
    {
      for (i = 1; i < BLOCKVECTOR_NBLOCKS (blockvector); i++)
        {
          if (BLOCK_START (BLOCKVECTOR_BLOCK (blockvector, i - 1))
              > BLOCK_START (BLOCKVECTOR_BLOCK (blockvector, i)))
            {
              CORE_ADDR start
                = BLOCK_START (BLOCKVECTOR_BLOCK (blockvector, i));

              complaint (_("block at %s out of order"),
                         hex_string ((LONGEST) start));
            }
        }
    }

  return (blockvector);
}
\f
/* Start recording information about source code that came from an
   included (or otherwise merged-in) source file with a different
   name.  NAME is the name of the file (cannot be NULL).  */

void
start_subfile (const char *name)
{
  const char *subfile_dirname;
  struct subfile *subfile;

  gdb_assert (buildsym_compunit != NULL);

  subfile_dirname = buildsym_compunit->comp_dir.get ();

  /* See if this subfile is already registered.  */

  for (subfile = buildsym_compunit->subfiles; subfile; subfile = subfile->next)
    {
      char *subfile_name;

      /* If NAME is an absolute path, and this subfile is not, then
         attempt to create an absolute path to compare.  */
      if (IS_ABSOLUTE_PATH (name)
          && !IS_ABSOLUTE_PATH (subfile->name)
          && subfile_dirname != NULL)
        subfile_name = concat (subfile_dirname, SLASH_STRING,
                               subfile->name, (char *) NULL);
      else
        subfile_name = subfile->name;

      if (FILENAME_CMP (subfile_name, name) == 0)
        {
          current_subfile = subfile;
          if (subfile_name != subfile->name)
            xfree (subfile_name);
          return;
        }
      if (subfile_name != subfile->name)
        xfree (subfile_name);
    }

  /* This subfile is not known.  Add an entry for it.  */

  subfile = XNEW (struct subfile);
  memset (subfile, 0, sizeof (struct subfile));
  subfile->buildsym_compunit = buildsym_compunit;

  subfile->next = buildsym_compunit->subfiles;
  buildsym_compunit->subfiles = subfile;

  current_subfile = subfile;

  subfile->name = xstrdup (name);

  /* Initialize line-number recording for this subfile.  */
  subfile->line_vector = NULL;

  /* Default the source language to whatever can be deduced from the
     filename.  If nothing can be deduced (such as for a C/C++ include
     file with a ".h" extension), then inherit whatever language the
     previous subfile had.  This kludgery is necessary because there
     is no standard way in some object formats to record the source
     language.  Also, when symtabs are allocated we try to deduce a
     language then as well, but it is too late for us to use that
     information while reading symbols, since symtabs aren't allocated
     until after all the symbols have been processed for a given
     source file.  */

  subfile->language = deduce_language_from_filename (subfile->name);
  if (subfile->language == language_unknown
      && subfile->next != NULL)
    {
      subfile->language = subfile->next->language;
    }

  /* If the filename of this subfile ends in .C, then change the
     language of any pending subfiles from C to C++.  We also accept
     any other C++ suffixes accepted by deduce_language_from_filename.  */
  /* Likewise for f2c.  */

  if (subfile->name)
    {
      struct subfile *s;
      enum language sublang = deduce_language_from_filename (subfile->name);

      if (sublang == language_cplus || sublang == language_fortran)
        for (s = buildsym_compunit->subfiles; s != NULL; s = s->next)
          if (s->language == language_c)
            s->language = sublang;
    }

  /* And patch up this file if necessary.  */
  if (subfile->language == language_c
      && subfile->next != NULL
      && (subfile->next->language == language_cplus
          || subfile->next->language == language_fortran))
    {
      subfile->language = subfile->next->language;
    }
}

/* Delete the buildsym compunit.  */

static void
free_buildsym_compunit (void)
{
  if (buildsym_compunit == NULL)
    return;
  delete buildsym_compunit;
  buildsym_compunit = NULL;
  current_subfile = NULL;
}

/* For stabs readers, the first N_SO symbol is assumed to be the
   source file name, and the subfile struct is initialized using that
   assumption.  If another N_SO symbol is later seen, immediately
   following the first one, then the first one is assumed to be the
   directory name and the second one is really the source file name.

   So we have to patch up the subfile struct by moving the old name
   value to dirname and remembering the new name.  Some sanity
   checking is performed to ensure that the state of the subfile
   struct is reasonable and that the old name we are assuming to be a
   directory name actually is (by checking for a trailing '/').  */

void
patch_subfile_names (struct subfile *subfile, const char *name)
{
  if (subfile != NULL
      && buildsym_compunit->comp_dir == NULL
      && subfile->name != NULL
      && IS_DIR_SEPARATOR (subfile->name[strlen (subfile->name) - 1]))
    {
      buildsym_compunit->comp_dir.reset (subfile->name);
      subfile->name = xstrdup (name);
      set_last_source_file (name);

      /* Default the source language to whatever can be deduced from
         the filename.  If nothing can be deduced (such as for a C/C++
         include file with a ".h" extension), then inherit whatever
         language the previous subfile had.  This kludgery is
         necessary because there is no standard way in some object
         formats to record the source language.  Also, when symtabs
         are allocated we try to deduce a language then as well, but
         it is too late for us to use that information while reading
         symbols, since symtabs aren't allocated until after all the
         symbols have been processed for a given source file.  */

      subfile->language = deduce_language_from_filename (subfile->name);
      if (subfile->language == language_unknown
          && subfile->next != NULL)
        {
          subfile->language = subfile->next->language;
        }
    }
}
\f
/* Handle the N_BINCL and N_EINCL symbol types that act like N_SOL for
   switching source files (different subfiles, as we call them) within
   one object file, but using a stack rather than in an arbitrary
   order.  */

void
push_subfile (void)
{
  struct subfile_stack *tem = XNEW (struct subfile_stack);

  tem->next = subfile_stack;
  subfile_stack = tem;
  if (current_subfile == NULL || current_subfile->name == NULL)
    {
      internal_error (__FILE__, __LINE__, 
                      _("failed internal consistency check"));
    }
  tem->name = current_subfile->name;
}

char *
pop_subfile (void)
{
  char *name;
  struct subfile_stack *link = subfile_stack;

  if (link == NULL)
    {
      internal_error (__FILE__, __LINE__,
                      _("failed internal consistency check"));
    }
  name = link->name;
  subfile_stack = link->next;
  xfree ((void *) link);
  return (name);
}
\f
/* Add a linetable entry for line number LINE and address PC to the
   line vector for SUBFILE.  */

void
record_line (struct subfile *subfile, int line, CORE_ADDR pc)
{
  struct linetable_entry *e;

  /* Ignore the dummy line number in libg.o */
  if (line == 0xffff)
    {
      return;
    }

  /* Make sure line vector exists and is big enough.  */
  if (!subfile->line_vector)
    {
      subfile->line_vector_length = INITIAL_LINE_VECTOR_LENGTH;
      subfile->line_vector = (struct linetable *)
        xmalloc (sizeof (struct linetable)
           + subfile->line_vector_length * sizeof (struct linetable_entry));
      subfile->line_vector->nitems = 0;
      have_line_numbers = 1;
    }

  if (subfile->line_vector->nitems + 1 >= subfile->line_vector_length)
    {
      subfile->line_vector_length *= 2;
      subfile->line_vector = (struct linetable *)
        xrealloc ((char *) subfile->line_vector,
                  (sizeof (struct linetable)
                   + (subfile->line_vector_length
                      * sizeof (struct linetable_entry))));
    }

  /* Normally, we treat lines as unsorted.  But the end of sequence
     marker is special.  We sort line markers at the same PC by line
     number, so end of sequence markers (which have line == 0) appear
     first.  This is right if the marker ends the previous function,
     and there is no padding before the next function.  But it is
     wrong if the previous line was empty and we are now marking a
     switch to a different subfile.  We must leave the end of sequence
     marker at the end of this group of lines, not sort the empty line
     to after the marker.  The easiest way to accomplish this is to
     delete any empty lines from our table, if they are followed by
     end of sequence markers.  All we lose is the ability to set
     breakpoints at some lines which contain no instructions
     anyway.  */
  if (line == 0 && subfile->line_vector->nitems > 0)
    {
      e = subfile->line_vector->item + subfile->line_vector->nitems - 1;
      while (subfile->line_vector->nitems > 0 && e->pc == pc)
        {
          e--;
          subfile->line_vector->nitems--;
        }
    }

  e = subfile->line_vector->item + subfile->line_vector->nitems++;
  e->line = line;
  e->pc = pc;
}

/* Needed in order to sort line tables from IBM xcoff files.  Sigh!  */

static int
compare_line_numbers (const void *ln1p, const void *ln2p)
{
  struct linetable_entry *ln1 = (struct linetable_entry *) ln1p;
  struct linetable_entry *ln2 = (struct linetable_entry *) ln2p;

  /* Note: this code does not assume that CORE_ADDRs can fit in ints.
     Please keep it that way.  */
  if (ln1->pc < ln2->pc)
    return -1;

  if (ln1->pc > ln2->pc)
    return 1;

  /* If pc equal, sort by line.  I'm not sure whether this is optimum
     behavior (see comment at struct linetable in symtab.h).  */
  return ln1->line - ln2->line;
}
\f
/* See buildsym.h.  */

struct compunit_symtab *
buildsym_compunit_symtab (void)
{
  gdb_assert (buildsym_compunit != NULL);

  return buildsym_compunit->compunit_symtab;
}

/* See buildsym.h.  */

struct macro_table *
get_macro_table (void)
{
  struct objfile *objfile;

  gdb_assert (buildsym_compunit != NULL);

  objfile = buildsym_compunit->objfile;

  if (! pending_macros)
    {
      pending_macros = new_macro_table (&objfile->per_bfd->storage_obstack,
                                        objfile->per_bfd->macro_cache,
                                        buildsym_compunit->compunit_symtab);
    }

  return pending_macros;
}
\f
/* Init state to prepare for building a symtab.
   Note: This can't be done in buildsym_init because dbxread.c and xcoffread.c
   can call start_symtab+end_symtab multiple times after one call to
   buildsym_init.  */

static void
prepare_for_building (const char *name, CORE_ADDR start_addr)
{
  set_last_source_file (name);
  last_source_start_addr = start_addr;

  local_symbols = NULL;
  local_using_directives = NULL;
  within_function = 0;
  have_line_numbers = 0;

  context_stack_depth = 0;

  /* These should have been reset either by successful completion of building
     a symtab, or by the scoped_free_pendings destructor.  */
  gdb_assert (file_symbols == NULL);
  gdb_assert (global_symbols == NULL);
  gdb_assert (global_using_directives == NULL);
  gdb_assert (pending_macros == NULL);
  gdb_assert (pending_addrmap == NULL);
  gdb_assert (current_subfile == NULL);
  gdb_assert (buildsym_compunit == nullptr);
}

/* Start a new symtab for a new source file in OBJFILE.  Called, for example,
   when a stabs symbol of type N_SO is seen, or when a DWARF
   TAG_compile_unit DIE is seen.  It indicates the start of data for
   one original source file.

   NAME is the name of the file (cannot be NULL).  COMP_DIR is the
   directory in which the file was compiled (or NULL if not known).
   START_ADDR is the lowest address of objects in the file (or 0 if
   not known).  LANGUAGE is the language of the source file, or
   language_unknown if not known, in which case it'll be deduced from
   the filename.  */

struct compunit_symtab *
start_symtab (struct objfile *objfile, const char *name, const char *comp_dir,
              CORE_ADDR start_addr, enum language language)
{
  prepare_for_building (name, start_addr);

  buildsym_compunit = new struct buildsym_compunit (objfile, comp_dir,
                                                    language);

  /* Allocate the compunit symtab now.  The caller needs it to allocate
     non-primary symtabs.  It is also needed by get_macro_table.  */
  buildsym_compunit->compunit_symtab = allocate_compunit_symtab (objfile,
                                                                 name);

  /* Build the subfile for NAME (the main source file) so that we can record
     a pointer to it for later.
     IMPORTANT: Do not allocate a struct symtab for NAME here.
     It can happen that the debug info provides a different path to NAME than
     DIRNAME,NAME.  We cope with this in watch_main_source_file_lossage but
     that only works if the main_subfile doesn't have a symtab yet.  */
  start_subfile (name);
  /* Save this so that we don't have to go looking for it at the end
     of the subfiles list.  */
  buildsym_compunit->main_subfile = current_subfile;

  return buildsym_compunit->compunit_symtab;
}

/* Restart compilation for a symtab.
   CUST is the result of end_expandable_symtab.
   NAME, START_ADDR are the source file we are resuming with.

   This is used when a symtab is built from multiple sources.
   The symtab is first built with start_symtab/end_expandable_symtab
   and then for each additional piece call restart_symtab/augment_*_symtab.
   Note: At the moment there is only augment_type_symtab.  */

void
restart_symtab (struct compunit_symtab *cust,
                const char *name, CORE_ADDR start_addr)
{
  prepare_for_building (name, start_addr);

  buildsym_compunit
    = new struct buildsym_compunit (COMPUNIT_OBJFILE (cust),
                                    COMPUNIT_DIRNAME (cust),
                                    compunit_language (cust));
  buildsym_compunit->compunit_symtab = cust;
}

/* Subroutine of end_symtab to simplify it.  Look for a subfile that
   matches the main source file's basename.  If there is only one, and
   if the main source file doesn't have any symbol or line number
   information, then copy this file's symtab and line_vector to the
   main source file's subfile and discard the other subfile.  This can
   happen because of a compiler bug or from the user playing games
   with #line or from things like a distributed build system that
   manipulates the debug info.  This can also happen from an innocent
   symlink in the paths, we don't canonicalize paths here.  */

static void
watch_main_source_file_lossage (void)
{
  struct subfile *mainsub, *subfile;

  /* We have to watch for buildsym_compunit == NULL here.  It's a quirk of
     end_symtab, it can return NULL so there may not be a main subfile.  */
  if (buildsym_compunit == NULL)
    return;

  /* Get the main source file.  */
  mainsub = buildsym_compunit->main_subfile;

  /* If the main source file doesn't have any line number or symbol
     info, look for an alias in another subfile.  */

  if (mainsub->line_vector == NULL
      && mainsub->symtab == NULL)
    {
      const char *mainbase = lbasename (mainsub->name);
      int nr_matches = 0;
      struct subfile *prevsub;
      struct subfile *mainsub_alias = NULL;
      struct subfile *prev_mainsub_alias = NULL;

      prevsub = NULL;
      for (subfile = buildsym_compunit->subfiles;
           subfile != NULL;
           subfile = subfile->next)
        {
          if (subfile == mainsub)
            continue;
          if (filename_cmp (lbasename (subfile->name), mainbase) == 0)
            {
              ++nr_matches;
              mainsub_alias = subfile;
              prev_mainsub_alias = prevsub;
            }
          prevsub = subfile;
        }

      if (nr_matches == 1)
        {
          gdb_assert (mainsub_alias != NULL && mainsub_alias != mainsub);

          /* Found a match for the main source file.
             Copy its line_vector and symtab to the main subfile
             and then discard it.  */

          mainsub->line_vector = mainsub_alias->line_vector;
          mainsub->line_vector_length = mainsub_alias->line_vector_length;
          mainsub->symtab = mainsub_alias->symtab;

          if (prev_mainsub_alias == NULL)
            buildsym_compunit->subfiles = mainsub_alias->next;
          else
            prev_mainsub_alias->next = mainsub_alias->next;
          xfree (mainsub_alias->name);
          xfree (mainsub_alias);
        }
    }
}

/* Reset state after a successful building of a symtab.
   This exists because dbxread.c and xcoffread.c can call
   start_symtab+end_symtab multiple times after one call to buildsym_init,
   and before the scoped_free_pendings destructor is called.
   We keep the free_pendings list around for dbx/xcoff sake.  */

static void
reset_symtab_globals (void)
{
  set_last_source_file (NULL);

  local_symbols = NULL;
  local_using_directives = NULL;
  file_symbols = NULL;
  global_symbols = NULL;
  global_using_directives = NULL;

  /* We don't free pending_macros here because if the symtab was successfully
     built then ownership was transferred to the symtab.  */
  pending_macros = NULL;

  if (pending_addrmap)
    obstack_free (&pending_addrmap_obstack, NULL);
  pending_addrmap = NULL;

  free_buildsym_compunit ();
}

/* Implementation of the first part of end_symtab.  It allows modifying
   STATIC_BLOCK before it gets finalized by end_symtab_from_static_block.
   If the returned value is NULL there is no blockvector created for
   this symtab (you still must call end_symtab_from_static_block).

   END_ADDR is the same as for end_symtab: the address of the end of the
   file's text.

   If EXPANDABLE is non-zero the STATIC_BLOCK dictionary is made
   expandable.

   If REQUIRED is non-zero, then a symtab is created even if it does
   not contain any symbols.  */

struct block *
end_symtab_get_static_block (CORE_ADDR end_addr, int expandable, int required)
{
  struct objfile *objfile = buildsym_compunit->objfile;

  /* Finish the lexical context of the last function in the file; pop
     the context stack.  */

  if (context_stack_depth > 0)
    {
      struct context_stack *cstk = pop_context ();

      /* Make a block for the local symbols within.  */
      finish_block (cstk->name, &local_symbols, cstk->old_blocks, NULL,
                    cstk->start_addr, end_addr);

      if (context_stack_depth > 0)
        {
          /* This is said to happen with SCO.  The old coffread.c
             code simply emptied the context stack, so we do the
             same.  FIXME: Find out why it is happening.  This is not
             believed to happen in most cases (even for coffread.c);
             it used to be an abort().  */
          complaint (_("Context stack not empty in end_symtab"));
          context_stack_depth = 0;
        }
    }

  /* Reordered executables may have out of order pending blocks; if
     OBJF_REORDERED is true, then sort the pending blocks.  */

  if ((objfile->flags & OBJF_REORDERED) && pending_blocks)
    {
      struct pending_block *pb;

      std::vector<block *> barray;

      for (pb = pending_blocks; pb != NULL; pb = pb->next)
        barray.push_back (pb->block);

      /* Sort blocks by start address in descending order.  Blocks with the
         same start address must remain in the original order to preserve
         inline function caller/callee relationships.  */
      std::stable_sort (barray.begin (), barray.end (),
                        [] (const block *a, const block *b)
                        {
                          return BLOCK_START (a) > BLOCK_START (b);
                        });

      int i = 0;
      for (pb = pending_blocks; pb != NULL; pb = pb->next)
        pb->block = barray[i++];
    }

  /* Cleanup any undefined types that have been left hanging around
     (this needs to be done before the finish_blocks so that
     file_symbols is still good).

     Both cleanup_undefined_stabs_types and finish_global_stabs are stabs
     specific, but harmless for other symbol readers, since on gdb
     startup or when finished reading stabs, the state is set so these
     are no-ops.  FIXME: Is this handled right in case of QUIT?  Can
     we make this cleaner?  */

  cleanup_undefined_stabs_types (objfile);
  finish_global_stabs (objfile);

  if (!required
      && pending_blocks == NULL
      && file_symbols == NULL
      && global_symbols == NULL
      && have_line_numbers == 0
      && pending_macros == NULL
      && global_using_directives == NULL)
    {
      /* Ignore symtabs that have no functions with real debugging info.  */
      return NULL;
    }
  else
    {
      /* Define the STATIC_BLOCK.  */
      return finish_block_internal (NULL, &file_symbols, NULL, NULL,
                                    last_source_start_addr, end_addr,
                                    0, expandable);
    }
}

/* Subroutine of end_symtab_from_static_block to simplify it.
   Handle the "have blockvector" case.
   See end_symtab_from_static_block for a description of the arguments.  */

static struct compunit_symtab *
end_symtab_with_blockvector (struct block *static_block,
                             int section, int expandable)
{
  struct objfile *objfile = buildsym_compunit->objfile;
  struct compunit_symtab *cu = buildsym_compunit->compunit_symtab;
  struct symtab *symtab;
  struct blockvector *blockvector;
  struct subfile *subfile;
  CORE_ADDR end_addr;

  gdb_assert (static_block != NULL);
  gdb_assert (buildsym_compunit != NULL);
  gdb_assert (buildsym_compunit->subfiles != NULL);

  end_addr = BLOCK_END (static_block);

  /* Create the GLOBAL_BLOCK and build the blockvector.  */
  finish_block_internal (NULL, &global_symbols, NULL, NULL,
                         last_source_start_addr, end_addr,
                         1, expandable);
  blockvector = make_blockvector ();

  /* Read the line table if it has to be read separately.
     This is only used by xcoffread.c.  */
  if (objfile->sf->sym_read_linetable != NULL)
    objfile->sf->sym_read_linetable (objfile);

  /* Handle the case where the debug info specifies a different path
     for the main source file.  It can cause us to lose track of its
     line number information.  */
  watch_main_source_file_lossage ();

  /* Now create the symtab objects proper, if not already done,
     one for each subfile.  */

  for (subfile = buildsym_compunit->subfiles;
       subfile != NULL;
       subfile = subfile->next)
    {
      int linetablesize = 0;

      if (subfile->line_vector)
        {
          linetablesize = sizeof (struct linetable) +
            subfile->line_vector->nitems * sizeof (struct linetable_entry);

          /* Like the pending blocks, the line table may be
             scrambled in reordered executables.  Sort it if
             OBJF_REORDERED is true.  */
          if (objfile->flags & OBJF_REORDERED)
            qsort (subfile->line_vector->item,
                   subfile->line_vector->nitems,
                   sizeof (struct linetable_entry), compare_line_numbers);
        }

      /* Allocate a symbol table if necessary.  */
      if (subfile->symtab == NULL)
        subfile->symtab = allocate_symtab (cu, subfile->name);
      symtab = subfile->symtab;

      /* Fill in its components.  */

      if (subfile->line_vector)
        {
          /* Reallocate the line table on the symbol obstack.  */
          SYMTAB_LINETABLE (symtab) = (struct linetable *)
            obstack_alloc (&objfile->objfile_obstack, linetablesize);
          memcpy (SYMTAB_LINETABLE (symtab), subfile->line_vector,
                  linetablesize);
        }
      else
        {
          SYMTAB_LINETABLE (symtab) = NULL;
        }

      /* Use whatever language we have been using for this
         subfile, not the one that was deduced in allocate_symtab
         from the filename.  We already did our own deducing when
         we created the subfile, and we may have altered our
         opinion of what language it is from things we found in
         the symbols.  */
      symtab->language = subfile->language;
    }

  /* Make sure the symtab of main_subfile is the first in its list.  */
  {
    struct symtab *main_symtab, *prev_symtab;

    main_symtab = buildsym_compunit->main_subfile->symtab;
    prev_symtab = NULL;
    ALL_COMPUNIT_FILETABS (cu, symtab)
      {
        if (symtab == main_symtab)
          {
            if (prev_symtab != NULL)
              {
                prev_symtab->next = main_symtab->next;
                main_symtab->next = COMPUNIT_FILETABS (cu);
                COMPUNIT_FILETABS (cu) = main_symtab;
              }
            break;
          }
        prev_symtab = symtab;
      }
    gdb_assert (main_symtab == COMPUNIT_FILETABS (cu));
  }

  /* Fill out the compunit symtab.  */

  if (buildsym_compunit->comp_dir != NULL)
    {
      /* Reallocate the dirname on the symbol obstack.  */
      const char *comp_dir = buildsym_compunit->comp_dir.get ();
      COMPUNIT_DIRNAME (cu)
        = (const char *) obstack_copy0 (&objfile->objfile_obstack,
                                        comp_dir, strlen (comp_dir));
    }

  /* Save the debug format string (if any) in the symtab.  */
  COMPUNIT_DEBUGFORMAT (cu) = buildsym_compunit->debugformat;

  /* Similarly for the producer.  */
  COMPUNIT_PRODUCER (cu) = buildsym_compunit->producer;

  COMPUNIT_BLOCKVECTOR (cu) = blockvector;
  {
    struct block *b = BLOCKVECTOR_BLOCK (blockvector, GLOBAL_BLOCK);

    set_block_compunit_symtab (b, cu);
  }

  COMPUNIT_BLOCK_LINE_SECTION (cu) = section;

  COMPUNIT_MACRO_TABLE (cu) = pending_macros;

  /* Default any symbols without a specified symtab to the primary symtab.  */
  {
    int block_i;

    /* The main source file's symtab.  */
    symtab = COMPUNIT_FILETABS (cu);

    for (block_i = 0; block_i < BLOCKVECTOR_NBLOCKS (blockvector); block_i++)
      {
        struct block *block = BLOCKVECTOR_BLOCK (blockvector, block_i);
        struct symbol *sym;
        struct dict_iterator iter;

        /* Inlined functions may have symbols not in the global or
           static symbol lists.  */
        if (BLOCK_FUNCTION (block) != NULL)
          if (symbol_symtab (BLOCK_FUNCTION (block)) == NULL)
            symbol_set_symtab (BLOCK_FUNCTION (block), symtab);

        /* Note that we only want to fix up symbols from the local
           blocks, not blocks coming from included symtabs.  That is why
           we use ALL_DICT_SYMBOLS here and not ALL_BLOCK_SYMBOLS.  */
        ALL_DICT_SYMBOLS (BLOCK_DICT (block), iter, sym)
          if (symbol_symtab (sym) == NULL)
            symbol_set_symtab (sym, symtab);
      }
  }

  add_compunit_symtab_to_objfile (cu);

  return cu;
}

/* Implementation of the second part of end_symtab.  Pass STATIC_BLOCK
   as value returned by end_symtab_get_static_block.

   SECTION is the same as for end_symtab: the section number
   (in objfile->section_offsets) of the blockvector and linetable.

   If EXPANDABLE is non-zero the GLOBAL_BLOCK dictionary is made
   expandable.  */

struct compunit_symtab *
end_symtab_from_static_block (struct block *static_block,
                              int section, int expandable)
{
  struct compunit_symtab *cu;

  if (static_block == NULL)
    {
      /* Handle the "no blockvector" case.
         When this happens there is nothing to record, so there's nothing
         to do: memory will be freed up later.

         Note: We won't be adding a compunit to the objfile's list of
         compunits, so there's nothing to unchain.  However, since each symtab
         is added to the objfile's obstack we can't free that space.
         We could do better, but this is believed to be a sufficiently rare
         event.  */
      cu = NULL;
    }
  else
    cu = end_symtab_with_blockvector (static_block, section, expandable);

  reset_symtab_globals ();

  return cu;
}

/* Finish the symbol definitions for one main source file, close off
   all the lexical contexts for that file (creating struct block's for
   them), then make the struct symtab for that file and put it in the
   list of all such.

   END_ADDR is the address of the end of the file's text.  SECTION is
   the section number (in objfile->section_offsets) of the blockvector
   and linetable.

   Note that it is possible for end_symtab() to return NULL.  In
   particular, for the DWARF case at least, it will return NULL when
   it finds a compilation unit that has exactly one DIE, a
   TAG_compile_unit DIE.  This can happen when we link in an object
   file that was compiled from an empty source file.  Returning NULL
   is probably not the correct thing to do, because then gdb will
   never know about this empty file (FIXME).

   If you need to modify STATIC_BLOCK before it is finalized you should
   call end_symtab_get_static_block and end_symtab_from_static_block
   yourself.  */

struct compunit_symtab *
end_symtab (CORE_ADDR end_addr, int section)
{
  struct block *static_block;

  static_block = end_symtab_get_static_block (end_addr, 0, 0);
  return end_symtab_from_static_block (static_block, section, 0);
}

/* Same as end_symtab except create a symtab that can be later added to.  */

struct compunit_symtab *
end_expandable_symtab (CORE_ADDR end_addr, int section)
{
  struct block *static_block;

  static_block = end_symtab_get_static_block (end_addr, 1, 0);
  return end_symtab_from_static_block (static_block, section, 1);
}

/* Subroutine of augment_type_symtab to simplify it.
   Attach the main source file's symtab to all symbols in PENDING_LIST that
   don't have one.  */

static void
set_missing_symtab (struct pending *pending_list,
                    struct compunit_symtab *cu)
{
  struct pending *pending;
  int i;

  for (pending = pending_list; pending != NULL; pending = pending->next)
    {
      for (i = 0; i < pending->nsyms; ++i)
        {
          if (symbol_symtab (pending->symbol[i]) == NULL)
            symbol_set_symtab (pending->symbol[i], COMPUNIT_FILETABS (cu));
        }
    }
}

/* Same as end_symtab, but for the case where we're adding more symbols
   to an existing symtab that is known to contain only type information.
   This is the case for DWARF4 Type Units.  */

void
augment_type_symtab (void)
{
  struct compunit_symtab *cust = buildsym_compunit->compunit_symtab;
  const struct blockvector *blockvector = COMPUNIT_BLOCKVECTOR (cust);

  if (context_stack_depth > 0)
    {
      complaint (_("Context stack not empty in augment_type_symtab"));
      context_stack_depth = 0;
    }
  if (pending_blocks != NULL)
    complaint (_("Blocks in a type symtab"));
  if (pending_macros != NULL)
    complaint (_("Macro in a type symtab"));
  if (have_line_numbers)
    complaint (_("Line numbers recorded in a type symtab"));

  if (file_symbols != NULL)
    {
      struct block *block = BLOCKVECTOR_BLOCK (blockvector, STATIC_BLOCK);

      /* First mark any symbols without a specified symtab as belonging
         to the primary symtab.  */
      set_missing_symtab (file_symbols, cust);

      dict_add_pending (BLOCK_DICT (block), file_symbols);
    }

  if (global_symbols != NULL)
    {
      struct block *block = BLOCKVECTOR_BLOCK (blockvector, GLOBAL_BLOCK);

      /* First mark any symbols without a specified symtab as belonging
         to the primary symtab.  */
      set_missing_symtab (global_symbols, cust);

      dict_add_pending (BLOCK_DICT (block), global_symbols);
    }

  reset_symtab_globals ();
}

/* Push a context block.  Args are an identifying nesting level
   (checkable when you pop it), and the starting PC address of this
   context.  */

struct context_stack *
push_context (int desc, CORE_ADDR valu)
{
  struct context_stack *newobj;

  if (context_stack_depth == context_stack_size)
    {
      context_stack_size *= 2;
      context_stack = (struct context_stack *)
        xrealloc ((char *) context_stack,
                  (context_stack_size * sizeof (struct context_stack)));
    }

  newobj = &context_stack[context_stack_depth++];
  newobj->depth = desc;
  newobj->locals = local_symbols;
  newobj->old_blocks = pending_blocks;
  newobj->start_addr = valu;
  newobj->local_using_directives = local_using_directives;
  newobj->name = NULL;

  local_symbols = NULL;
  local_using_directives = NULL;

  return newobj;
}

/* Pop a context block.  Returns the address of the context block just
   popped.  */

struct context_stack *
pop_context (void)
{
  gdb_assert (context_stack_depth > 0);
  return (&context_stack[--context_stack_depth]);
}

\f

/* Compute a small integer hash code for the given name.  */

int
hashname (const char *name)
{
    return (hash(name,strlen(name)) % HASHSIZE);
}
\f

void
record_debugformat (const char *format)
{
  buildsym_compunit->debugformat = format;
}

void
record_producer (const char *producer)
{
  buildsym_compunit->producer = producer;
}

/* Merge the first symbol list SRCLIST into the second symbol list
   TARGETLIST by repeated calls to add_symbol_to_list().  This
   procedure "frees" each link of SRCLIST by adding it to the
   free_pendings list.  Caller must set SRCLIST to a null list after
   calling this function.

   Void return.  */

void
merge_symbol_lists (struct pending **srclist, struct pending **targetlist)
{
  int i;

  if (!srclist || !*srclist)
    return;

  /* Merge in elements from current link.  */
  for (i = 0; i < (*srclist)->nsyms; i++)
    add_symbol_to_list ((*srclist)->symbol[i], targetlist);

  /* Recurse on next.  */
  merge_symbol_lists (&(*srclist)->next, targetlist);

  /* "Free" the current link.  */
  (*srclist)->next = free_pendings;
  free_pendings = (*srclist);
}
\f

/* Name of source file whose symbol data we are now processing.  This
   comes from a symbol of type N_SO for stabs.  For Dwarf it comes
   from the DW_AT_name attribute of a DW_TAG_compile_unit DIE.  */

static char *last_source_file;

/* See buildsym.h.  */

void
set_last_source_file (const char *name)
{
  xfree (last_source_file);
  last_source_file = name == NULL ? NULL : xstrdup (name);
}

/* See buildsym.h.  */

const char *
get_last_source_file (void)
{
  return last_source_file;
}

\f

/* Initialize anything that needs initializing when starting to read a
   fresh piece of a symbol file, e.g. reading in the stuff
   corresponding to a psymtab.  */

void
buildsym_init (void)
{
  subfile_stack = NULL;

  pending_addrmap_interesting = 0;

  /* Context stack is initially empty.  Allocate first one with room
     for a few levels; reuse it forever afterward.  */
  if (context_stack == NULL)
    {
      context_stack_size = INITIAL_CONTEXT_STACK_SIZE;
      context_stack = XNEWVEC (struct context_stack, context_stack_size);
    }

  /* Ensure the scoped_free_pendings destructor was called after
     the last time.  */
  gdb_assert (free_pendings == NULL);
  gdb_assert (pending_blocks == NULL);
  gdb_assert (file_symbols == NULL);
  gdb_assert (global_symbols == NULL);
  gdb_assert (global_using_directives == NULL);
  gdb_assert (pending_macros == NULL);
  gdb_assert (pending_addrmap == NULL);
  gdb_assert (buildsym_compunit == NULL);
}

/* Initialize anything that needs initializing when a completely new
   symbol file is specified (not just adding some symbols from another
   file, e.g. a shared library).  */

void
buildsym_new_init (void)
{
  buildsym_init ();
}