text: /* GDB routines for manipulating objfiles.
  
     Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
     2002, 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
  
     Contributed by Cygnus Support, using pieces from other GDB modules.
  
     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 file contains support routines for creating, manipulating, and
     destroying objfile structures. */
  
  #include "defs.h"
  #include "bfd.h"		/* Binary File Description */
  #include "symtab.h"
  #include "symfile.h"
  #include "objfiles.h"
  #include "gdb-stabs.h"
  #include "target.h"
  #include "bcache.h"
  #include "mdebugread.h"
  #include "expression.h"
  #include "parser-defs.h"
  
  #include "gdb_assert.h"
  #include <sys/types.h>
  #include "gdb_stat.h"
  #include <fcntl.h>
  #include "gdb_obstack.h"
  #include "gdb_string.h"
  #include "hashtab.h"
  
  #include "breakpoint.h"
  #include "block.h"
  #include "dictionary.h"
  #include "source.h"
  #include "addrmap.h"
  
  /* Prototypes for local functions */
  
  static void objfile_alloc_data (struct objfile *objfile);
  static void objfile_free_data (struct objfile *objfile);
  
  /* Externally visible variables that are owned by this module.
     See declarations in objfile.h for more info. */
  
  struct objfile *object_files;	/* Linked list of all objfiles */
  struct objfile *current_objfile;	/* For symbol file being read in */
  struct objfile *symfile_objfile;	/* Main symbol table loaded from */
  struct objfile *rt_common_objfile;	/* For runtime common symbols */
  
  /* Locate all mappable sections of a BFD file. 
     objfile_p_char is a char * to get it through
     bfd_map_over_sections; we cast it back to its proper type.  */
  
  #ifndef TARGET_KEEP_SECTION
  #define TARGET_KEEP_SECTION(ASECT)	0
  #endif
  
  /* Called via bfd_map_over_sections to build up the section table that
     the objfile references.  The objfile contains pointers to the start
     of the table (objfile->sections) and to the first location after
     the end of the table (objfile->sections_end). */
  
  static void
  add_to_objfile_sections (struct bfd *abfd, struct bfd_section *asect,
  			 void *objfile_p_char)
  {
    struct objfile *objfile = (struct objfile *) objfile_p_char;
    struct obj_section section;
    flagword aflag;
  
    aflag = bfd_get_section_flags (abfd, asect);
  
    if (!(aflag & SEC_ALLOC) && !(TARGET_KEEP_SECTION (asect)))
      return;
  
    if (0 == bfd_section_size (abfd, asect))
      return;
    section.offset = 0;
    section.objfile = objfile;
    section.the_bfd_section = asect;
    section.ovly_mapped = 0;
    section.addr = bfd_section_vma (abfd, asect);
    section.endaddr = section.addr + bfd_section_size (abfd, asect);
    obstack_grow (&objfile->objfile_obstack, (char *) &section, sizeof (section));
    objfile->sections_end = (struct obj_section *) (((unsigned long) objfile->sections_end) + 1);
  }
  
  /* Builds a section table for OBJFILE.
     Returns 0 if OK, 1 on error (in which case bfd_error contains the
     error).
  
     Note that while we are building the table, which goes into the
     psymbol obstack, we hijack the sections_end pointer to instead hold
     a count of the number of sections.  When bfd_map_over_sections
     returns, this count is used to compute the pointer to the end of
     the sections table, which then overwrites the count.
  
     Also note that the OFFSET and OVLY_MAPPED in each table entry
     are initialized to zero.
  
     Also note that if anything else writes to the psymbol obstack while
     we are building the table, we're pretty much hosed. */
  
  int
  build_objfile_section_table (struct objfile *objfile)
  {
    /* objfile->sections can be already set when reading a mapped symbol
       file.  I believe that we do need to rebuild the section table in
       this case (we rebuild other things derived from the bfd), but we
       can't free the old one (it's in the objfile_obstack).  So we just
       waste some memory.  */
  
    objfile->sections_end = 0;
    bfd_map_over_sections (objfile->obfd, add_to_objfile_sections, (char *) objfile);
    objfile->sections = (struct obj_section *)
      obstack_finish (&objfile->objfile_obstack);
    objfile->sections_end = objfile->sections + (unsigned long) objfile->sections_end;
    return (0);
  }
  
  /* Given a pointer to an initialized bfd (ABFD) and some flag bits
     allocate a new objfile struct, fill it in as best we can, link it
     into the list of all known objfiles, and return a pointer to the
     new objfile struct.
  
     The FLAGS word contains various bits (OBJF_*) that can be taken as
     requests for specific operations.  Other bits like OBJF_SHARED are
     simply copied through to the new objfile flags member. */
  
  /* NOTE: carlton/2003-02-04: This function is called with args NULL, 0
     by jv-lang.c, to create an artificial objfile used to hold
     information about dynamically-loaded Java classes.  Unfortunately,
     that branch of this function doesn't get tested very frequently, so
     it's prone to breakage.  (E.g. at one time the name was set to NULL
     in that situation, which broke a loop over all names in the dynamic
     library loader.)  If you change this function, please try to leave
     things in a consistent state even if abfd is NULL.  */
  
  struct objfile *
  allocate_objfile (bfd *abfd, int flags)
  {
    struct objfile *objfile = NULL;
    struct objfile *last_one = NULL;
  
    /* If we don't support mapped symbol files, didn't ask for the file to be
       mapped, or failed to open the mapped file for some reason, then revert
       back to an unmapped objfile. */
  
    if (objfile == NULL)
      {
        objfile = (struct objfile *) xmalloc (sizeof (struct objfile));
        memset (objfile, 0, sizeof (struct objfile));
        objfile->md = NULL;
        objfile->psymbol_cache = bcache_xmalloc ();
        objfile->macro_cache = bcache_xmalloc ();
        /* We could use obstack_specify_allocation here instead, but
  	 gdb_obstack.h specifies the alloc/dealloc functions.  */
        obstack_init (&objfile->objfile_obstack);
        terminate_minimal_symbol_table (objfile);
      }
  
    objfile_alloc_data (objfile);
  
    /* Update the per-objfile information that comes from the bfd, ensuring
       that any data that is reference is saved in the per-objfile data
       region. */
  
    objfile->obfd = abfd;
    if (objfile->name != NULL)
      {
        xfree (objfile->name);
      }
    if (abfd != NULL)
      {
        objfile->name = xstrdup (bfd_get_filename (abfd));
        objfile->mtime = bfd_get_mtime (abfd);
  
        /* Build section table.  */
  
        if (build_objfile_section_table (objfile))
  	{
  	  error (_("Can't find the file sections in `%s': %s"),
  		 objfile->name, bfd_errmsg (bfd_get_error ()));
  	}
      }
    else
      {
        objfile->name = xstrdup ("<<anonymous objfile>>");
      }
  
    /* Initialize the section indexes for this objfile, so that we can
       later detect if they are used w/o being properly assigned to. */
  
    objfile->sect_index_text = -1;
    objfile->sect_index_data = -1;
    objfile->sect_index_bss = -1;
    objfile->sect_index_rodata = -1;
  
    /* We don't yet have a C++-specific namespace symtab.  */
  
    objfile->cp_namespace_symtab = NULL;
  
    /* Add this file onto the tail of the linked list of other such files. */
  
    objfile->next = NULL;
    if (object_files == NULL)
      object_files = objfile;
    else
      {
        for (last_one = object_files;
  	   last_one->next;
  	   last_one = last_one->next);
        last_one->next = objfile;
      }
  
    /* Save passed in flag bits. */
    objfile->flags |= flags;
  
    return (objfile);
  }
  
  /* Initialize entry point information for this objfile. */
  
  void
  init_entry_point_info (struct objfile *objfile)
  {
    /* Save startup file's range of PC addresses to help blockframe.c
       decide where the bottom of the stack is.  */
  
    if (bfd_get_file_flags (objfile->obfd) & EXEC_P)
      {
        /* Executable file -- record its entry point so we'll recognize
           the startup file because it contains the entry point.  */
        objfile->ei.entry_point = bfd_get_start_address (objfile->obfd);
      }
    else
      {
        /* Examination of non-executable.o files.  Short-circuit this stuff.  */
        objfile->ei.entry_point = INVALID_ENTRY_POINT;
      }
  }
  
  /* Get current entry point address.  */
  
  CORE_ADDR
  entry_point_address (void)
  {
    return symfile_objfile ? symfile_objfile->ei.entry_point : 0;
  }
  
  /* Create the terminating entry of OBJFILE's minimal symbol table.
     If OBJFILE->msymbols is zero, allocate a single entry from
     OBJFILE->objfile_obstack; otherwise, just initialize
     OBJFILE->msymbols[OBJFILE->minimal_symbol_count].  */
  void
  terminate_minimal_symbol_table (struct objfile *objfile)
  {
    if (! objfile->msymbols)
      objfile->msymbols = ((struct minimal_symbol *)
                           obstack_alloc (&objfile->objfile_obstack,
                                          sizeof (objfile->msymbols[0])));
  
    {
      struct minimal_symbol *m
        = &objfile->msymbols[objfile->minimal_symbol_count];
  
      memset (m, 0, sizeof (*m));
      /* Don't rely on these enumeration values being 0's.  */
      MSYMBOL_TYPE (m) = mst_unknown;
      SYMBOL_INIT_LANGUAGE_SPECIFIC (m, language_unknown);
    }
  }
  
  
  /* Put one object file before a specified on in the global list.
     This can be used to make sure an object file is destroyed before
     another when using ALL_OBJFILES_SAFE to free all objfiles. */
  void
  put_objfile_before (struct objfile *objfile, struct objfile *before_this)
  {
    struct objfile **objp;
  
    unlink_objfile (objfile);
    
    for (objp = &object_files; *objp != NULL; objp = &((*objp)->next))
      {
        if (*objp == before_this)
  	{
  	  objfile->next = *objp;
  	  *objp = objfile;
  	  return;
  	}
      }
    
    internal_error (__FILE__, __LINE__,
  		  _("put_objfile_before: before objfile not in list"));
  }
  
  /* Put OBJFILE at the front of the list.  */
  
  void
  objfile_to_front (struct objfile *objfile)
  {
    struct objfile **objp;
    for (objp = &object_files; *objp != NULL; objp = &((*objp)->next))
      {
        if (*objp == objfile)
  	{
  	  /* Unhook it from where it is.  */
  	  *objp = objfile->next;
  	  /* Put it in the front.  */
  	  objfile->next = object_files;
  	  object_files = objfile;
  	  break;
  	}
      }
  }
  
  /* Unlink OBJFILE from the list of known objfiles, if it is found in the
     list.
  
     It is not a bug, or error, to call this function if OBJFILE is not known
     to be in the current list.  This is done in the case of mapped objfiles,
     for example, just to ensure that the mapped objfile doesn't appear twice
     in the list.  Since the list is threaded, linking in a mapped objfile
     twice would create a circular list.
  
     If OBJFILE turns out to be in the list, we zap it's NEXT pointer after
     unlinking it, just to ensure that we have completely severed any linkages
     between the OBJFILE and the list. */
  
  void
  unlink_objfile (struct objfile *objfile)
  {
    struct objfile **objpp;
  
    for (objpp = &object_files; *objpp != NULL; objpp = &((*objpp)->next))
      {
        if (*objpp == objfile)
  	{
  	  *objpp = (*objpp)->next;
  	  objfile->next = NULL;
  	  return;
  	}
      }
  
    internal_error (__FILE__, __LINE__,
  		  _("unlink_objfile: objfile already unlinked"));
  }
  
  
  /* Destroy an objfile and all the symtabs and psymtabs under it.  Note
     that as much as possible is allocated on the objfile_obstack 
     so that the memory can be efficiently freed.
  
     Things which we do NOT free because they are not in malloc'd memory
     or not in memory specific to the objfile include:
  
     objfile -> sf
  
     FIXME:  If the objfile is using reusable symbol information (via mmalloc),
     then we need to take into account the fact that more than one process
     may be using the symbol information at the same time (when mmalloc is
     extended to support cooperative locking).  When more than one process
     is using the mapped symbol info, we need to be more careful about when
     we free objects in the reusable area. */
  
  void
  free_objfile (struct objfile *objfile)
  {
    if (objfile->separate_debug_objfile)
      {
        free_objfile (objfile->separate_debug_objfile);
      }
    
    if (objfile->separate_debug_objfile_backlink)
      {
        /* We freed the separate debug file, make sure the base objfile
  	 doesn't reference it.  */
        objfile->separate_debug_objfile_backlink->separate_debug_objfile = NULL;
      }
    
    /* Remove any references to this objfile in the global value
       lists.  */
    preserve_values (objfile);
  
    /* First do any symbol file specific actions required when we are
       finished with a particular symbol file.  Note that if the objfile
       is using reusable symbol information (via mmalloc) then each of
       these routines is responsible for doing the correct thing, either
       freeing things which are valid only during this particular gdb
       execution, or leaving them to be reused during the next one. */
  
    if (objfile->sf != NULL)
      {
        (*objfile->sf->sym_finish) (objfile);
      }
  
    /* We always close the bfd. */
  
    if (objfile->obfd != NULL)
      {
        char *name = bfd_get_filename (objfile->obfd);
        if (!bfd_close (objfile->obfd))
  	warning (_("cannot close \"%s\": %s"),
  		 name, bfd_errmsg (bfd_get_error ()));
        xfree (name);
      }
  
    /* Remove it from the chain of all objfiles. */
  
    unlink_objfile (objfile);
  
    /* If we are going to free the runtime common objfile, mark it
       as unallocated.  */
  
    if (objfile == rt_common_objfile)
      rt_common_objfile = NULL;
  
    /* Before the symbol table code was redone to make it easier to
       selectively load and remove information particular to a specific
       linkage unit, gdb used to do these things whenever the monolithic
       symbol table was blown away.  How much still needs to be done
       is unknown, but we play it safe for now and keep each action until
       it is shown to be no longer needed. */
  
    /* Not all our callers call clear_symtab_users (objfile_purge_solibs,
       for example), so we need to call this here.  */
    clear_pc_function_cache ();
  
    /* Clear globals which might have pointed into a removed objfile.
       FIXME: It's not clear which of these are supposed to persist
       between expressions and which ought to be reset each time.  */
    expression_context_block = NULL;
    innermost_block = NULL;
  
    /* Check to see if the current_source_symtab belongs to this objfile,
       and if so, call clear_current_source_symtab_and_line. */
  
    {
      struct symtab_and_line cursal = get_current_source_symtab_and_line ();
      struct symtab *s;
  
      ALL_OBJFILE_SYMTABS (objfile, s)
        {
  	if (s == cursal.symtab)
  	  clear_current_source_symtab_and_line ();
        }
    }
  
    /* The last thing we do is free the objfile struct itself. */
  
    objfile_free_data (objfile);
    if (objfile->name != NULL)
      {
        xfree (objfile->name);
      }
    if (objfile->global_psymbols.list)
      xfree (objfile->global_psymbols.list);
    if (objfile->static_psymbols.list)
      xfree (objfile->static_psymbols.list);
    /* Free the obstacks for non-reusable objfiles */
    bcache_xfree (objfile->psymbol_cache);
    bcache_xfree (objfile->macro_cache);
    if (objfile->demangled_names_hash)
      htab_delete (objfile->demangled_names_hash);
    obstack_free (&objfile->objfile_obstack, 0);
    xfree (objfile);
    objfile = NULL;
  }
  
  static void
  do_free_objfile_cleanup (void *obj)
  {
    free_objfile (obj);
  }
  
  struct cleanup *
  make_cleanup_free_objfile (struct objfile *obj)
  {
    return make_cleanup (do_free_objfile_cleanup, obj);
  }
  
  /* Free all the object files at once and clean up their users.  */
  
  void
  free_all_objfiles (void)
  {
    struct objfile *objfile, *temp;
  
    ALL_OBJFILES_SAFE (objfile, temp)
    {
      free_objfile (objfile);
    }
    clear_symtab_users ();
  }
  
  /* Relocate OBJFILE to NEW_OFFSETS.  There should be OBJFILE->NUM_SECTIONS
     entries in new_offsets.  */
  void
  objfile_relocate (struct objfile *objfile, struct section_offsets *new_offsets)
  {
    struct section_offsets *delta =
      ((struct section_offsets *) 
       alloca (SIZEOF_N_SECTION_OFFSETS (objfile->num_sections)));
  
    {
      int i;
      int something_changed = 0;
      for (i = 0; i < objfile->num_sections; ++i)
        {
  	delta->offsets[i] =
  	  ANOFFSET (new_offsets, i) - ANOFFSET (objfile->section_offsets, i);
  	if (ANOFFSET (delta, i) != 0)
  	  something_changed = 1;
        }
      if (!something_changed)
        return;
    }
  
    /* OK, get all the symtabs.  */
    {
      struct symtab *s;
  
      ALL_OBJFILE_SYMTABS (objfile, s)
      {
        struct linetable *l;
        struct blockvector *bv;
        int i;
  
        /* First the line table.  */
        l = LINETABLE (s);
        if (l)
  	{
  	  for (i = 0; i < l->nitems; ++i)
  	    l->item[i].pc += ANOFFSET (delta, s->block_line_section);
  	}
  
        /* Don't relocate a shared blockvector more than once.  */
        if (!s->primary)
  	continue;
  
        bv = BLOCKVECTOR (s);
        for (i = 0; i < BLOCKVECTOR_NBLOCKS (bv); ++i)
  	{
  	  struct block *b;
  	  struct symbol *sym;
  	  struct dict_iterator iter;
  
  	  b = BLOCKVECTOR_BLOCK (bv, i);
  	  BLOCK_START (b) += ANOFFSET (delta, s->block_line_section);
  	  BLOCK_END (b) += ANOFFSET (delta, s->block_line_section);
            if (BLOCKVECTOR_MAP (bv))
              addrmap_relocate (BLOCKVECTOR_MAP (bv),
                                ANOFFSET (delta, s->block_line_section));
  
  	  ALL_BLOCK_SYMBOLS (b, iter, sym)
  	    {
  	      fixup_symbol_section (sym, objfile);
  
  	      /* The RS6000 code from which this was taken skipped
  	         any symbols in STRUCT_DOMAIN or UNDEF_DOMAIN.
  	         But I'm leaving out that test, on the theory that
  	         they can't possibly pass the tests below.  */
  	      if ((SYMBOL_CLASS (sym) == LOC_LABEL
  		   || SYMBOL_CLASS (sym) == LOC_STATIC
  		   || SYMBOL_CLASS (sym) == LOC_INDIRECT)
  		  && SYMBOL_SECTION (sym) >= 0)
  		{
  		  SYMBOL_VALUE_ADDRESS (sym) +=
  		    ANOFFSET (delta, SYMBOL_SECTION (sym));
  		}
  	    }
  	}
      }
    }
  
    {
      struct partial_symtab *p;
  
      ALL_OBJFILE_PSYMTABS (objfile, p)
      {
        p->textlow += ANOFFSET (delta, SECT_OFF_TEXT (objfile));
        p->texthigh += ANOFFSET (delta, SECT_OFF_TEXT (objfile));
      }
    }
  
    {
      struct partial_symbol **psym;
  
      for (psym = objfile->global_psymbols.list;
  	 psym < objfile->global_psymbols.next;
  	 psym++)
        {
  	fixup_psymbol_section (*psym, objfile);
  	if (SYMBOL_SECTION (*psym) >= 0)
  	  SYMBOL_VALUE_ADDRESS (*psym) += ANOFFSET (delta,
  						    SYMBOL_SECTION (*psym));
        }
      for (psym = objfile->static_psymbols.list;
  	 psym < objfile->static_psymbols.next;
  	 psym++)
        {
  	fixup_psymbol_section (*psym, objfile);
  	if (SYMBOL_SECTION (*psym) >= 0)
  	  SYMBOL_VALUE_ADDRESS (*psym) += ANOFFSET (delta,
  						    SYMBOL_SECTION (*psym));
        }
    }
  
    {
      struct minimal_symbol *msym;
      ALL_OBJFILE_MSYMBOLS (objfile, msym)
        if (SYMBOL_SECTION (msym) >= 0)
        SYMBOL_VALUE_ADDRESS (msym) += ANOFFSET (delta, SYMBOL_SECTION (msym));
    }
    /* Relocating different sections by different amounts may cause the symbols
       to be out of order.  */
    msymbols_sort (objfile);
  
    {
      int i;
      for (i = 0; i < objfile->num_sections; ++i)
        (objfile->section_offsets)->offsets[i] = ANOFFSET (new_offsets, i);
    }
  
    if (objfile->ei.entry_point != ~(CORE_ADDR) 0)
      {
        /* Relocate ei.entry_point with its section offset, use SECT_OFF_TEXT
  	 only as a fallback.  */
        struct obj_section *s;
        s = find_pc_section (objfile->ei.entry_point);
        if (s)
          objfile->ei.entry_point += ANOFFSET (delta, s->the_bfd_section->index);
        else
          objfile->ei.entry_point += ANOFFSET (delta, SECT_OFF_TEXT (objfile));
      }
  
    {
      struct obj_section *s;
      bfd *abfd;
  
      abfd = objfile->obfd;
  
      ALL_OBJFILE_OSECTIONS (objfile, s)
        {
        	int idx = s->the_bfd_section->index;
  	
  	s->addr += ANOFFSET (delta, idx);
  	s->endaddr += ANOFFSET (delta, idx);
        }
    }
  
    /* Relocate breakpoints as necessary, after things are relocated. */
    breakpoint_re_set ();
  }
  
  /* Many places in gdb want to test just to see if we have any partial
     symbols available.  This function returns zero if none are currently
     available, nonzero otherwise. */
  
  int
  have_partial_symbols (void)
  {
    struct objfile *ofp;
  
    ALL_OBJFILES (ofp)
    {
      if (ofp->psymtabs != NULL)
        {
  	return 1;
        }
    }
    return 0;
  }
  
  /* Many places in gdb want to test just to see if we have any full
     symbols available.  This function returns zero if none are currently
     available, nonzero otherwise. */
  
  int
  have_full_symbols (void)
  {
    struct objfile *ofp;
  
    ALL_OBJFILES (ofp)
    {
      if (ofp->symtabs != NULL)
        {
  	return 1;
        }
    }
    return 0;
  }
  
  
  /* This operations deletes all objfile entries that represent solibs that
     weren't explicitly loaded by the user, via e.g., the add-symbol-file
     command.
   */
  void
  objfile_purge_solibs (void)
  {
    struct objfile *objf;
    struct objfile *temp;
  
    ALL_OBJFILES_SAFE (objf, temp)
    {
      /* We assume that the solib package has been purged already, or will
         be soon.
       */
      if (!(objf->flags & OBJF_USERLOADED) && (objf->flags & OBJF_SHARED))
        free_objfile (objf);
    }
  }
  
  
  /* Many places in gdb want to test just to see if we have any minimal
     symbols available.  This function returns zero if none are currently
     available, nonzero otherwise. */
  
  int
  have_minimal_symbols (void)
  {
    struct objfile *ofp;
  
    ALL_OBJFILES (ofp)
    {
      if (ofp->minimal_symbol_count > 0)
        {
  	return 1;
        }
    }
    return 0;
  }
  
  /* Returns a section whose range includes PC and SECTION, or NULL if
     none found.  Note the distinction between the return type, struct
     obj_section (which is defined in gdb), and the input type "struct
     bfd_section" (which is a bfd-defined data type).  The obj_section
     contains a pointer to the "struct bfd_section".  */
  
  struct obj_section *
  find_pc_sect_section (CORE_ADDR pc, struct bfd_section *section)
  {
    struct obj_section *s;
    struct objfile *objfile;
  
    ALL_OBJSECTIONS (objfile, s)
      if ((section == 0 || section == s->the_bfd_section) &&
  	s->addr <= pc && pc < s->endaddr)
        return (s);
  
    return (NULL);
  }
  
  /* Returns a section whose range includes PC or NULL if none found. 
     Backward compatibility, no section.  */
  
  struct obj_section *
  find_pc_section (CORE_ADDR pc)
  {
    return find_pc_sect_section (pc, find_pc_mapped_section (pc));
  }
  
  
  /* In SVR4, we recognize a trampoline by it's section name. 
     That is, if the pc is in a section named ".plt" then we are in
     a trampoline.  */
  
  int
  in_plt_section (CORE_ADDR pc, char *name)
  {
    struct obj_section *s;
    int retval = 0;
  
    s = find_pc_section (pc);
  
    retval = (s != NULL
  	    && s->the_bfd_section->name != NULL
  	    && strcmp (s->the_bfd_section->name, ".plt") == 0);
    return (retval);
  }
  
  
  /* Keep a registry of per-objfile data-pointers required by other GDB
     modules.  */
  
  struct objfile_data
  {
    unsigned index;
  };
  
  struct objfile_data_registration
  {
    struct objfile_data *data;
    struct objfile_data_registration *next;
  };
    
  struct objfile_data_registry
  {
    struct objfile_data_registration *registrations;
    unsigned num_registrations;
  };
  
  static struct objfile_data_registry objfile_data_registry = { NULL, 0 };
  
  const struct objfile_data *
  register_objfile_data (void)
  {
    struct objfile_data_registration **curr;
  
    /* Append new registration.  */
    for (curr = &objfile_data_registry.registrations;
         *curr != NULL; curr = &(*curr)->next);
  
    *curr = XMALLOC (struct objfile_data_registration);
    (*curr)->next = NULL;
    (*curr)->data = XMALLOC (struct objfile_data);
    (*curr)->data->index = objfile_data_registry.num_registrations++;
  
    return (*curr)->data;
  }
  
  static void
  objfile_alloc_data (struct objfile *objfile)
  {
    gdb_assert (objfile->data == NULL);
    objfile->num_data = objfile_data_registry.num_registrations;
    objfile->data = XCALLOC (objfile->num_data, void *);
  }
  
  static void
  objfile_free_data (struct objfile *objfile)
  {
    gdb_assert (objfile->data != NULL);
    xfree (objfile->data);
    objfile->data = NULL;
  }
  
  void
  clear_objfile_data (struct objfile *objfile)
  {
    gdb_assert (objfile->data != NULL);
    memset (objfile->data, 0, objfile->num_data * sizeof (void *));
  }
  
  void
  set_objfile_data (struct objfile *objfile, const struct objfile_data *data,
  		  void *value)
  {
    gdb_assert (data->index < objfile->num_data);
    objfile->data[data->index] = value;
  }
  
  void *
  objfile_data (struct objfile *objfile, const struct objfile_data *data)
  {
    gdb_assert (data->index < objfile->num_data);
    return objfile->data[data->index];
  }
  