Simplify DWARF file name caching

[binutils-gdb.git] / bfd / dwarf2.c

/* DWARF 2 support.
   Copyright (C) 1994-2021 Free Software Foundation, Inc.

   Adapted from gdb/dwarf2read.c by Gavin Koch of Cygnus Solutions
   (gavin@cygnus.com).

   From the dwarf2read.c header:
   Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
   Inc.  with support from Florida State University (under contract
   with the Ada Joint Program Office), and Silicon Graphics, Inc.
   Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
   based on Fred Fish's (Cygnus Support) implementation of DWARF 1
   support in dwarfread.c

   This file is part of BFD.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include "sysdep.h"
#include "bfd.h"
#include "libiberty.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "dwarf2.h"
#include "hashtab.h"

/* The data in the .debug_line statement prologue looks like this.  */

struct line_head
{
  bfd_vma total_length;
  unsigned short version;
  bfd_vma prologue_length;
  unsigned char minimum_instruction_length;
  unsigned char maximum_ops_per_insn;
  unsigned char default_is_stmt;
  int line_base;
  unsigned char line_range;
  unsigned char opcode_base;
  unsigned char *standard_opcode_lengths;
};

/* Attributes have a name and a value.  */

struct attribute
{
  enum dwarf_attribute name;
  enum dwarf_form form;
  union
  {
    char *str;
    struct dwarf_block *blk;
    bfd_uint64_t val;
    bfd_int64_t sval;
  }
  u;
};

/* Blocks are a bunch of untyped bytes.  */
struct dwarf_block
{
  unsigned int size;
  bfd_byte *data;
};

struct adjusted_section
{
  asection *section;
  bfd_vma adj_vma;
};

struct dwarf2_debug_file
{
  /* The actual bfd from which debug info was loaded.  Might be
     different to orig_bfd because of gnu_debuglink sections.  */
  bfd *bfd_ptr;

  /* Pointer to the symbol table.  */
  asymbol **syms;

  /* The current info pointer for the .debug_info section being parsed.  */
  bfd_byte *info_ptr;

  /* A pointer to the memory block allocated for .debug_info sections.  */
  bfd_byte *dwarf_info_buffer;

  /* Length of the loaded .debug_info sections.  */
  bfd_size_type dwarf_info_size;

  /* Pointer to the .debug_abbrev section loaded into memory.  */
  bfd_byte *dwarf_abbrev_buffer;

  /* Length of the loaded .debug_abbrev section.  */
  bfd_size_type dwarf_abbrev_size;

  /* Buffer for decode_line_info.  */
  bfd_byte *dwarf_line_buffer;

  /* Length of the loaded .debug_line section.  */
  bfd_size_type dwarf_line_size;

  /* Pointer to the .debug_str section loaded into memory.  */
  bfd_byte *dwarf_str_buffer;

  /* Length of the loaded .debug_str section.  */
  bfd_size_type dwarf_str_size;

  /* Pointer to the .debug_line_str section loaded into memory.  */
  bfd_byte *dwarf_line_str_buffer;

  /* Length of the loaded .debug_line_str section.  */
  bfd_size_type dwarf_line_str_size;

  /* Pointer to the .debug_ranges section loaded into memory.  */
  bfd_byte *dwarf_ranges_buffer;

  /* Length of the loaded .debug_ranges section.  */
  bfd_size_type dwarf_ranges_size;

  /* Pointer to the .debug_rnglists section loaded into memory.  */
  bfd_byte *dwarf_rnglists_buffer;

  /* Length of the loaded .debug_rnglists section.  */
  bfd_size_type dwarf_rnglists_size;

  /* A list of all previously read comp_units.  */
  struct comp_unit *all_comp_units;

  /* Last comp unit in list above.  */
  struct comp_unit *last_comp_unit;

  /* Line table at line_offset zero.  */
  struct line_info_table *line_table;

  /* Hash table to map offsets to decoded abbrevs.  */
  htab_t abbrev_offsets;
};

struct dwarf2_debug
{
  /* Names of the debug sections.  */
  const struct dwarf_debug_section *debug_sections;

  /* Per-file stuff.  */
  struct dwarf2_debug_file f, alt;

  /* Pointer to the original bfd for which debug was loaded.  This is what
     we use to compare and so check that the cached debug data is still
     valid - it saves having to possibly dereference the gnu_debuglink each
     time.  */
  bfd *orig_bfd;

  /* If the most recent call to bfd_find_nearest_line was given an
     address in an inlined function, preserve a pointer into the
     calling chain for subsequent calls to bfd_find_inliner_info to
     use.  */
  struct funcinfo *inliner_chain;

  /* Section VMAs at the time the stash was built.  */
  bfd_vma *sec_vma;
  /* Number of sections in the SEC_VMA table.  */
  unsigned int sec_vma_count;

  /* Number of sections whose VMA we must adjust.  */
  int adjusted_section_count;

  /* Array of sections with adjusted VMA.  */
  struct adjusted_section *adjusted_sections;

  /* Number of times find_line is called.  This is used in
     the heuristic for enabling the info hash tables.  */
  int info_hash_count;

#define STASH_INFO_HASH_TRIGGER    100

  /* Hash table mapping symbol names to function infos.  */
  struct info_hash_table *funcinfo_hash_table;

  /* Hash table mapping symbol names to variable infos.  */
  struct info_hash_table *varinfo_hash_table;

  /* Head of comp_unit list in the last hash table update.  */
  struct comp_unit *hash_units_head;

  /* Status of info hash.  */
  int info_hash_status;
#define STASH_INFO_HASH_OFF        0
#define STASH_INFO_HASH_ON         1
#define STASH_INFO_HASH_DISABLED   2

  /* True if we opened bfd_ptr.  */
  bool close_on_cleanup;
};

struct arange
{
  struct arange *next;
  bfd_vma low;
  bfd_vma high;
};

/* A minimal decoding of DWARF2 compilation units.  We only decode
   what's needed to get to the line number information.  */

struct comp_unit
{
  /* Chain the previously read compilation units.  */
  struct comp_unit *next_unit;

  /* Likewise, chain the compilation unit read after this one.
     The comp units are stored in reversed reading order.  */
  struct comp_unit *prev_unit;

  /* Keep the bfd convenient (for memory allocation).  */
  bfd *abfd;

  /* The lowest and highest addresses contained in this compilation
     unit as specified in the compilation unit header.  */
  struct arange arange;

  /* The DW_AT_name attribute (for error messages).  */
  char *name;

  /* The abbrev hash table.  */
  struct abbrev_info **abbrevs;

  /* DW_AT_language.  */
  int lang;

  /* Note that an error was found by comp_unit_find_nearest_line.  */
  int error;

  /* The DW_AT_comp_dir attribute.  */
  char *comp_dir;

  /* TRUE if there is a line number table associated with this comp. unit.  */
  int stmtlist;

  /* Pointer to the current comp_unit so that we can find a given entry
     by its reference.  */
  bfd_byte *info_ptr_unit;

  /* The offset into .debug_line of the line number table.  */
  unsigned long line_offset;

  /* Pointer to the first child die for the comp unit.  */
  bfd_byte *first_child_die_ptr;

  /* The end of the comp unit.  */
  bfd_byte *end_ptr;

  /* The decoded line number, NULL if not yet decoded.  */
  struct line_info_table *line_table;

  /* A list of the functions found in this comp. unit.  */
  struct funcinfo *function_table;

  /* A table of function information references searchable by address.  */
  struct lookup_funcinfo *lookup_funcinfo_table;

  /* Number of functions in the function_table and sorted_function_table.  */
  bfd_size_type number_of_functions;

  /* A list of the variables found in this comp. unit.  */
  struct varinfo *variable_table;

  /* Pointers to dwarf2_debug structures.  */
  struct dwarf2_debug *stash;
  struct dwarf2_debug_file *file;

  /* DWARF format version for this unit - from unit header.  */
  int version;

  /* Address size for this unit - from unit header.  */
  unsigned char addr_size;

  /* Offset size for this unit - from unit header.  */
  unsigned char offset_size;

  /* Base address for this unit - from DW_AT_low_pc attribute of
     DW_TAG_compile_unit DIE */
  bfd_vma base_address;

  /* TRUE if symbols are cached in hash table for faster lookup by name.  */
  bool cached;
};

/* This data structure holds the information of an abbrev.  */
struct abbrev_info
{
  unsigned int         number;          /* Number identifying abbrev.  */
  enum dwarf_tag       tag;             /* DWARF tag.  */
  bool                 has_children;    /* TRUE if the abbrev has children.  */
  unsigned int         num_attrs;       /* Number of attributes.  */
  struct attr_abbrev * attrs;           /* An array of attribute descriptions.  */
  struct abbrev_info * next;            /* Next in chain.  */
};

struct attr_abbrev
{
  enum dwarf_attribute name;
  enum dwarf_form form;
  bfd_vma implicit_const;
};

/* Map of uncompressed DWARF debug section name to compressed one.  It
   is terminated by NULL uncompressed_name.  */

const struct dwarf_debug_section dwarf_debug_sections[] =
{
  { ".debug_abbrev",            ".zdebug_abbrev" },
  { ".debug_aranges",           ".zdebug_aranges" },
  { ".debug_frame",             ".zdebug_frame" },
  { ".debug_info",              ".zdebug_info" },
  { ".debug_info",              ".zdebug_info" },
  { ".debug_line",              ".zdebug_line" },
  { ".debug_loc",               ".zdebug_loc" },
  { ".debug_macinfo",           ".zdebug_macinfo" },
  { ".debug_macro",             ".zdebug_macro" },
  { ".debug_pubnames",          ".zdebug_pubnames" },
  { ".debug_pubtypes",          ".zdebug_pubtypes" },
  { ".debug_ranges",            ".zdebug_ranges" },
  { ".debug_rnglists",          ".zdebug_rnglist" },
  { ".debug_static_func",       ".zdebug_static_func" },
  { ".debug_static_vars",       ".zdebug_static_vars" },
  { ".debug_str",               ".zdebug_str", },
  { ".debug_str",               ".zdebug_str", },
  { ".debug_line_str",          ".zdebug_line_str", },
  { ".debug_types",             ".zdebug_types" },
  /* GNU DWARF 1 extensions */
  { ".debug_sfnames",           ".zdebug_sfnames" },
  { ".debug_srcinfo",           ".zebug_srcinfo" },
  /* SGI/MIPS DWARF 2 extensions */
  { ".debug_funcnames",         ".zdebug_funcnames" },
  { ".debug_typenames",         ".zdebug_typenames" },
  { ".debug_varnames",          ".zdebug_varnames" },
  { ".debug_weaknames",         ".zdebug_weaknames" },
  { NULL,                       NULL },
};

/* NB/ Numbers in this enum must match up with indices
   into the dwarf_debug_sections[] array above.  */
enum dwarf_debug_section_enum
{
  debug_abbrev = 0,
  debug_aranges,
  debug_frame,
  debug_info,
  debug_info_alt,
  debug_line,
  debug_loc,
  debug_macinfo,
  debug_macro,
  debug_pubnames,
  debug_pubtypes,
  debug_ranges,
  debug_rnglists,
  debug_static_func,
  debug_static_vars,
  debug_str,
  debug_str_alt,
  debug_line_str,
  debug_types,
  debug_sfnames,
  debug_srcinfo,
  debug_funcnames,
  debug_typenames,
  debug_varnames,
  debug_weaknames,
  debug_max
};

/* A static assertion.  */
extern int dwarf_debug_section_assert[ARRAY_SIZE (dwarf_debug_sections)
                                      == debug_max + 1 ? 1 : -1];

#ifndef ABBREV_HASH_SIZE
#define ABBREV_HASH_SIZE 121
#endif
#ifndef ATTR_ALLOC_CHUNK
#define ATTR_ALLOC_CHUNK 4
#endif

/* Variable and function hash tables.  This is used to speed up look-up
   in lookup_symbol_in_var_table() and lookup_symbol_in_function_table().
   In order to share code between variable and function infos, we use
   a list of untyped pointer for all variable/function info associated with
   a symbol.  We waste a bit of memory for list with one node but that
   simplifies the code.  */

struct info_list_node
{
  struct info_list_node *next;
  void *info;
};

/* Info hash entry.  */
struct info_hash_entry
{
  struct bfd_hash_entry root;
  struct info_list_node *head;
};

struct info_hash_table
{
  struct bfd_hash_table base;
};

/* Function to create a new entry in info hash table.  */

static struct bfd_hash_entry *
info_hash_table_newfunc (struct bfd_hash_entry *entry,
                         struct bfd_hash_table *table,
                         const char *string)
{
  struct info_hash_entry *ret = (struct info_hash_entry *) entry;

  /* Allocate the structure if it has not already been allocated by a
     derived class.  */
  if (ret == NULL)
    {
      ret = (struct info_hash_entry *) bfd_hash_allocate (table,
                                                          sizeof (* ret));
      if (ret == NULL)
        return NULL;
    }

  /* Call the allocation method of the base class.  */
  ret = ((struct info_hash_entry *)
         bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));

  /* Initialize the local fields here.  */
  if (ret)
    ret->head = NULL;

  return (struct bfd_hash_entry *) ret;
}

/* Function to create a new info hash table.  It returns a pointer to the
   newly created table or NULL if there is any error.  We need abfd
   solely for memory allocation.  */

static struct info_hash_table *
create_info_hash_table (bfd *abfd)
{
  struct info_hash_table *hash_table;

  hash_table = ((struct info_hash_table *)
                bfd_alloc (abfd, sizeof (struct info_hash_table)));
  if (!hash_table)
    return hash_table;

  if (!bfd_hash_table_init (&hash_table->base, info_hash_table_newfunc,
                            sizeof (struct info_hash_entry)))
    {
      bfd_release (abfd, hash_table);
      return NULL;
    }

  return hash_table;
}

/* Insert an info entry into an info hash table.  We do not check of
   duplicate entries.  Also, the caller need to guarantee that the
   right type of info in inserted as info is passed as a void* pointer.
   This function returns true if there is no error.  */

static bool
insert_info_hash_table (struct info_hash_table *hash_table,
                        const char *key,
                        void *info,
                        bool copy_p)
{
  struct info_hash_entry *entry;
  struct info_list_node *node;

  entry = (struct info_hash_entry*) bfd_hash_lookup (&hash_table->base,
                                                     key, true, copy_p);
  if (!entry)
    return false;

  node = (struct info_list_node *) bfd_hash_allocate (&hash_table->base,
                                                      sizeof (*node));
  if (!node)
    return false;

  node->info = info;
  node->next = entry->head;
  entry->head = node;

  return true;
}

/* Look up an info entry list from an info hash table.  Return NULL
   if there is none.  */

static struct info_list_node *
lookup_info_hash_table (struct info_hash_table *hash_table, const char *key)
{
  struct info_hash_entry *entry;

  entry = (struct info_hash_entry*) bfd_hash_lookup (&hash_table->base, key,
                                                     false, false);
  return entry ? entry->head : NULL;
}

/* Read a section into its appropriate place in the dwarf2_debug
   struct (indicated by SECTION_BUFFER and SECTION_SIZE).  If SYMS is
   not NULL, use bfd_simple_get_relocated_section_contents to read the
   section contents, otherwise use bfd_get_section_contents.  Fail if
   the located section does not contain at least OFFSET bytes.  */

static bool
read_section (bfd *           abfd,
              const struct dwarf_debug_section *sec,
              asymbol **      syms,
              bfd_uint64_t    offset,
              bfd_byte **     section_buffer,
              bfd_size_type * section_size)
{
  const char *section_name = sec->uncompressed_name;
  bfd_byte *contents = *section_buffer;

  /* The section may have already been read.  */
  if (contents == NULL)
    {
      bfd_size_type amt;
      asection *msec;
      ufile_ptr filesize;

      msec = bfd_get_section_by_name (abfd, section_name);
      if (msec == NULL)
        {
          section_name = sec->compressed_name;
          msec = bfd_get_section_by_name (abfd, section_name);
        }
      if (msec == NULL)
        {
          _bfd_error_handler (_("DWARF error: can't find %s section."),
                              sec->uncompressed_name);
          bfd_set_error (bfd_error_bad_value);
          return false;
        }

      amt = bfd_get_section_limit_octets (abfd, msec);
      filesize = bfd_get_file_size (abfd);
      if (amt >= filesize)
        {
          /* PR 26946 */
          _bfd_error_handler (_("DWARF error: section %s is larger than its filesize! (0x%lx vs 0x%lx)"),
                              section_name, (long) amt, (long) filesize);
          bfd_set_error (bfd_error_bad_value);
          return false;
        }
      *section_size = amt;
      /* Paranoia - alloc one extra so that we can make sure a string
         section is NUL terminated.  */
      amt += 1;
      if (amt == 0)
        {
          /* Paranoia - this should never happen.  */
          bfd_set_error (bfd_error_no_memory);
          return false;
        }
      contents = (bfd_byte *) bfd_malloc (amt);
      if (contents == NULL)
        return false;
      if (syms
          ? !bfd_simple_get_relocated_section_contents (abfd, msec, contents,
                                                        syms)
          : !bfd_get_section_contents (abfd, msec, contents, 0, *section_size))
        {
          free (contents);
          return false;
        }
      contents[*section_size] = 0;
      *section_buffer = contents;
    }

  /* It is possible to get a bad value for the offset into the section
     that the client wants.  Validate it here to avoid trouble later.  */
  if (offset != 0 && offset >= *section_size)
    {
      /* xgettext: c-format */
      _bfd_error_handler (_("DWARF error: offset (%" PRIu64 ")"
                            " greater than or equal to %s size (%" PRIu64 ")"),
                          (uint64_t) offset, section_name,
                          (uint64_t) *section_size);
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  return true;
}

/* Read dwarf information from a buffer.  */

static inline uint64_t
read_n_bytes (bfd *abfd, bfd_byte **ptr, bfd_byte *end, int n)
{
  bfd_byte *buf = *ptr;
  if (end - buf < n)
    {
      *ptr = end;
      return 0;
    }
  *ptr = buf + n;
  return bfd_get (n * 8, abfd, buf);
}

static unsigned int
read_1_byte (bfd *abfd, bfd_byte **ptr, bfd_byte *end)
{
  return read_n_bytes (abfd, ptr, end, 1);
}

static int
read_1_signed_byte (bfd *abfd ATTRIBUTE_UNUSED, bfd_byte **ptr, bfd_byte *end)
{
  bfd_byte *buf = *ptr;
  if (end - buf < 1)
    {
      *ptr = end;
      return 0;
    }
  *ptr = buf + 1;
  return bfd_get_signed_8 (abfd, buf);
}

static unsigned int
read_2_bytes (bfd *abfd, bfd_byte **ptr, bfd_byte *end)
{
  return read_n_bytes (abfd, ptr, end, 2);
}

static unsigned int
read_3_bytes (bfd *abfd, bfd_byte **ptr, bfd_byte *end)
{
  unsigned int val = read_1_byte (abfd, ptr, end);
  val <<= 8;
  val |= read_1_byte (abfd, ptr, end);
  val <<= 8;
  val |= read_1_byte (abfd, ptr, end);
  if (bfd_little_endian (abfd))
    val = (((val >> 16) & 0xff)
           | (val & 0xff00)
           | ((val & 0xff) << 16));
  return val;
}

static unsigned int
read_4_bytes (bfd *abfd, bfd_byte **ptr, bfd_byte *end)
{
  return read_n_bytes (abfd, ptr, end, 4);
}

static uint64_t
read_8_bytes (bfd *abfd, bfd_byte **ptr, bfd_byte *end)
{
  return read_n_bytes (abfd, ptr, end, 8);
}

static struct dwarf_block *
read_blk (bfd *abfd, bfd_byte **ptr, bfd_byte *end, size_t size)
{
  bfd_byte *buf = *ptr;
  struct dwarf_block *block;

  block = (struct dwarf_block *) bfd_alloc (abfd, sizeof (*block));
  if (block == NULL)
    return NULL;

  if (size > (size_t) (end - buf))
    {
      *ptr = end;
      block->data = NULL;
      block->size = 0;
    }
  else
    {
      *ptr = buf + size;
      block->data = buf;
      block->size = size;
    }
  return block;
}

/* Scans a NUL terminated string starting at *PTR, returning a pointer to it.
   Bytes at or beyond BUF_END will not be read.  Returns NULL if the
   terminator is not found or if the string is empty.  *PTR is
   incremented over the bytes scanned, including the terminator.  */

static char *
read_string (bfd_byte **ptr,
             bfd_byte *buf_end)
{
  bfd_byte *buf = *ptr;
  bfd_byte *str = buf;

  while (buf < buf_end)
    if (*buf++ == 0)
      {
        if (str == buf - 1)
          break;
        *ptr = buf;
        return (char *) str;
      }

  *ptr = buf;
  return NULL;
}

/* Reads an offset from *PTR and then locates the string at this offset
   inside the debug string section.  Returns a pointer to the string.
   Increments *PTR by the number of bytes read for the offset.  This
   value is set even if the function fails.  Bytes at or beyond
   BUF_END will not be read.  Returns NULL if there was a problem, or
   if the string is empty.  Does not check for NUL termination of the
   string.  */

static char *
read_indirect_string (struct comp_unit *unit,
                      bfd_byte **ptr,
                      bfd_byte *buf_end)
{
  bfd_uint64_t offset;
  struct dwarf2_debug *stash = unit->stash;
  struct dwarf2_debug_file *file = unit->file;
  char *str;

  if (unit->offset_size > (size_t) (buf_end - *ptr))
    {
      *ptr = buf_end;
      return NULL;
    }

  if (unit->offset_size == 4)
    offset = read_4_bytes (unit->abfd, ptr, buf_end);
  else
    offset = read_8_bytes (unit->abfd, ptr, buf_end);

  if (! read_section (unit->abfd, &stash->debug_sections[debug_str],
                      file->syms, offset,
                      &file->dwarf_str_buffer, &file->dwarf_str_size))
    return NULL;

  str = (char *) file->dwarf_str_buffer + offset;
  if (*str == '\0')
    return NULL;
  return str;
}

/* Like read_indirect_string but from .debug_line_str section.  */

static char *
read_indirect_line_string (struct comp_unit *unit,
                           bfd_byte **ptr,
                           bfd_byte *buf_end)
{
  bfd_uint64_t offset;
  struct dwarf2_debug *stash = unit->stash;
  struct dwarf2_debug_file *file = unit->file;
  char *str;

  if (unit->offset_size > (size_t) (buf_end - *ptr))
    {
      *ptr = buf_end;
      return NULL;
    }

  if (unit->offset_size == 4)
    offset = read_4_bytes (unit->abfd, ptr, buf_end);
  else
    offset = read_8_bytes (unit->abfd, ptr, buf_end);

  if (! read_section (unit->abfd, &stash->debug_sections[debug_line_str],
                      file->syms, offset,
                      &file->dwarf_line_str_buffer,
                      &file->dwarf_line_str_size))
    return NULL;

  str = (char *) file->dwarf_line_str_buffer + offset;
  if (*str == '\0')
    return NULL;
  return str;
}

/* Like read_indirect_string but uses a .debug_str located in
   an alternate file pointed to by the .gnu_debugaltlink section.
   Used to impement DW_FORM_GNU_strp_alt.  */

static char *
read_alt_indirect_string (struct comp_unit *unit,
                          bfd_byte **ptr,
                          bfd_byte *buf_end)
{
  bfd_uint64_t offset;
  struct dwarf2_debug *stash = unit->stash;
  char *str;

  if (unit->offset_size > (size_t) (buf_end - *ptr))
    {
      *ptr = buf_end;
      return NULL;
    }

  if (unit->offset_size == 4)
    offset = read_4_bytes (unit->abfd, ptr, buf_end);
  else
    offset = read_8_bytes (unit->abfd, ptr, buf_end);

  if (stash->alt.bfd_ptr == NULL)
    {
      bfd *debug_bfd;
      char *debug_filename = bfd_follow_gnu_debugaltlink (unit->abfd, DEBUGDIR);

      if (debug_filename == NULL)
        return NULL;

      debug_bfd = bfd_openr (debug_filename, NULL);
      free (debug_filename);
      if (debug_bfd == NULL)
        /* FIXME: Should we report our failure to follow the debuglink ?  */
        return NULL;

      if (!bfd_check_format (debug_bfd, bfd_object))
        {
          bfd_close (debug_bfd);
          return NULL;
        }
      stash->alt.bfd_ptr = debug_bfd;
    }

  if (! read_section (unit->stash->alt.bfd_ptr,
                      stash->debug_sections + debug_str_alt,
                      stash->alt.syms, offset,
                      &stash->alt.dwarf_str_buffer,
                      &stash->alt.dwarf_str_size))
    return NULL;

  str = (char *) stash->alt.dwarf_str_buffer + offset;
  if (*str == '\0')
    return NULL;

  return str;
}

/* Resolve an alternate reference from UNIT at OFFSET.
   Returns a pointer into the loaded alternate CU upon success
   or NULL upon failure.  */

static bfd_byte *
read_alt_indirect_ref (struct comp_unit * unit,
                       bfd_uint64_t       offset)
{
  struct dwarf2_debug *stash = unit->stash;

  if (stash->alt.bfd_ptr == NULL)
    {
      bfd *debug_bfd;
      char *debug_filename = bfd_follow_gnu_debugaltlink (unit->abfd, DEBUGDIR);

      if (debug_filename == NULL)
        return NULL;

      debug_bfd = bfd_openr (debug_filename, NULL);
      free (debug_filename);
      if (debug_bfd == NULL)
        /* FIXME: Should we report our failure to follow the debuglink ?  */
        return NULL;

      if (!bfd_check_format (debug_bfd, bfd_object))
        {
          bfd_close (debug_bfd);
          return NULL;
        }
      stash->alt.bfd_ptr = debug_bfd;
    }

  if (! read_section (unit->stash->alt.bfd_ptr,
                      stash->debug_sections + debug_info_alt,
                      stash->alt.syms, offset,
                      &stash->alt.dwarf_info_buffer,
                      &stash->alt.dwarf_info_size))
    return NULL;

  return stash->alt.dwarf_info_buffer + offset;
}

static bfd_uint64_t
read_address (struct comp_unit *unit, bfd_byte **ptr, bfd_byte *buf_end)
{
  bfd_byte *buf = *ptr;
  int signed_vma = 0;

  if (bfd_get_flavour (unit->abfd) == bfd_target_elf_flavour)
    signed_vma = get_elf_backend_data (unit->abfd)->sign_extend_vma;

  if (unit->addr_size > (size_t) (buf_end - buf))
    {
      *ptr = buf_end;
      return 0;
    }

  *ptr = buf + unit->addr_size;
  if (signed_vma)
    {
      switch (unit->addr_size)
        {
        case 8:
          return bfd_get_signed_64 (unit->abfd, buf);
        case 4:
          return bfd_get_signed_32 (unit->abfd, buf);
        case 2:
          return bfd_get_signed_16 (unit->abfd, buf);
        default:
          abort ();
        }
    }
  else
    {
      switch (unit->addr_size)
        {
        case 8:
          return bfd_get_64 (unit->abfd, buf);
        case 4:
          return bfd_get_32 (unit->abfd, buf);
        case 2:
          return bfd_get_16 (unit->abfd, buf);
        default:
          abort ();
        }
    }
}

/* Lookup an abbrev_info structure in the abbrev hash table.  */

static struct abbrev_info *
lookup_abbrev (unsigned int number, struct abbrev_info **abbrevs)
{
  unsigned int hash_number;
  struct abbrev_info *abbrev;

  hash_number = number % ABBREV_HASH_SIZE;
  abbrev = abbrevs[hash_number];

  while (abbrev)
    {
      if (abbrev->number == number)
        return abbrev;
      else
        abbrev = abbrev->next;
    }

  return NULL;
}

/* We keep a hash table to map .debug_abbrev section offsets to the
   array of abbrevs, so that compilation units using the same set of
   abbrevs do not waste memory.  */

struct abbrev_offset_entry
{
  size_t offset;
  struct abbrev_info **abbrevs;
};

static hashval_t
hash_abbrev (const void *p)
{
  const struct abbrev_offset_entry *ent = p;
  return htab_hash_pointer ((void *) ent->offset);
}

static int
eq_abbrev (const void *pa, const void *pb)
{
  const struct abbrev_offset_entry *a = pa;
  const struct abbrev_offset_entry *b = pb;
  return a->offset == b->offset;
}

static void
del_abbrev (void *p)
{
  struct abbrev_offset_entry *ent = p;
  struct abbrev_info **abbrevs = ent->abbrevs;
  size_t i;

  for (i = 0; i < ABBREV_HASH_SIZE; i++)
    {
      struct abbrev_info *abbrev = abbrevs[i];

      while (abbrev)
        {
          free (abbrev->attrs);
          abbrev = abbrev->next;
        }
    }
  free (ent);
}

/* In DWARF version 2, the description of the debugging information is
   stored in a separate .debug_abbrev section.  Before we read any
   dies from a section we read in all abbreviations and install them
   in a hash table.  */

static struct abbrev_info**
read_abbrevs (bfd *abfd, bfd_uint64_t offset, struct dwarf2_debug *stash,
              struct dwarf2_debug_file *file)
{
  struct abbrev_info **abbrevs;
  bfd_byte *abbrev_ptr;
  bfd_byte *abbrev_end;
  struct abbrev_info *cur_abbrev;
  unsigned int abbrev_number, abbrev_name;
  unsigned int abbrev_form, hash_number;
  size_t amt;
  void **slot;
  struct abbrev_offset_entry ent = { offset, NULL };

  if (ent.offset != offset)
    return NULL;

  slot = htab_find_slot (file->abbrev_offsets, &ent, INSERT);
  if (slot == NULL)
    return NULL;
  if (*slot != NULL)
    return ((struct abbrev_offset_entry *) (*slot))->abbrevs;

  if (! read_section (abfd, &stash->debug_sections[debug_abbrev],
                      file->syms, offset,
                      &file->dwarf_abbrev_buffer,
                      &file->dwarf_abbrev_size))
    return NULL;

  amt = sizeof (struct abbrev_info*) * ABBREV_HASH_SIZE;
  abbrevs = (struct abbrev_info **) bfd_zalloc (abfd, amt);
  if (abbrevs == NULL)
    return NULL;

  abbrev_ptr = file->dwarf_abbrev_buffer + offset;
  abbrev_end = file->dwarf_abbrev_buffer + file->dwarf_abbrev_size;
  abbrev_number = _bfd_safe_read_leb128 (abfd, &abbrev_ptr,
                                         false, abbrev_end);

  /* Loop until we reach an abbrev number of 0.  */
  while (abbrev_number)
    {
      amt = sizeof (struct abbrev_info);
      cur_abbrev = (struct abbrev_info *) bfd_zalloc (abfd, amt);
      if (cur_abbrev == NULL)
        goto fail;

      /* Read in abbrev header.  */
      cur_abbrev->number = abbrev_number;
      cur_abbrev->tag = (enum dwarf_tag)
        _bfd_safe_read_leb128 (abfd, &abbrev_ptr,
                               false, abbrev_end);
      cur_abbrev->has_children = read_1_byte (abfd, &abbrev_ptr, abbrev_end);

      /* Now read in declarations.  */
      for (;;)
        {
          /* Initialize it just to avoid a GCC false warning.  */
          bfd_vma implicit_const = -1;

          abbrev_name = _bfd_safe_read_leb128 (abfd, &abbrev_ptr,
                                               false, abbrev_end);
          abbrev_form = _bfd_safe_read_leb128 (abfd, &abbrev_ptr,
                                               false, abbrev_end);
          if (abbrev_form == DW_FORM_implicit_const)
            implicit_const = _bfd_safe_read_leb128 (abfd, &abbrev_ptr,
                                                    true, abbrev_end);
          if (abbrev_name == 0)
            break;

          if ((cur_abbrev->num_attrs % ATTR_ALLOC_CHUNK) == 0)
            {
              struct attr_abbrev *tmp;

              amt = cur_abbrev->num_attrs + ATTR_ALLOC_CHUNK;
              amt *= sizeof (struct attr_abbrev);
              tmp = (struct attr_abbrev *) bfd_realloc (cur_abbrev->attrs, amt);
              if (tmp == NULL)
                goto fail;
              cur_abbrev->attrs = tmp;
            }

          cur_abbrev->attrs[cur_abbrev->num_attrs].name
            = (enum dwarf_attribute) abbrev_name;
          cur_abbrev->attrs[cur_abbrev->num_attrs].form
            = (enum dwarf_form) abbrev_form;
          cur_abbrev->attrs[cur_abbrev->num_attrs].implicit_const
            = implicit_const;
          ++cur_abbrev->num_attrs;
        }

      hash_number = abbrev_number % ABBREV_HASH_SIZE;
      cur_abbrev->next = abbrevs[hash_number];
      abbrevs[hash_number] = cur_abbrev;

      /* Get next abbreviation.
         Under Irix6 the abbreviations for a compilation unit are not
         always properly terminated with an abbrev number of 0.
         Exit loop if we encounter an abbreviation which we have
         already read (which means we are about to read the abbreviations
         for the next compile unit) or if the end of the abbreviation
         table is reached.  */
      if ((size_t) (abbrev_ptr - file->dwarf_abbrev_buffer)
          >= file->dwarf_abbrev_size)
        break;
      abbrev_number = _bfd_safe_read_leb128 (abfd, &abbrev_ptr,
                                             false, abbrev_end);
      if (lookup_abbrev (abbrev_number, abbrevs) != NULL)
        break;
    }

  *slot = bfd_malloc (sizeof ent);
  if (!*slot)
    goto fail;
  ent.abbrevs = abbrevs;
  memcpy (*slot, &ent, sizeof ent);
  return abbrevs;

 fail:
  if (abbrevs != NULL)
    {
      size_t i;

      for (i = 0; i < ABBREV_HASH_SIZE; i++)
        {
          struct abbrev_info *abbrev = abbrevs[i];

          while (abbrev)
            {
              free (abbrev->attrs);
              abbrev = abbrev->next;
            }
        }
      free (abbrevs);
    }
  return NULL;
}

/* Returns true if the form is one which has a string value.  */

static inline bool
is_str_attr (enum dwarf_form form)
{
  return (form == DW_FORM_string
          || form == DW_FORM_strp
          || form == DW_FORM_strx
          || form == DW_FORM_strx1
          || form == DW_FORM_strx2
          || form == DW_FORM_strx3
          || form == DW_FORM_strx4
          || form == DW_FORM_line_strp
          || form == DW_FORM_GNU_strp_alt);
}

static const char *
read_indexed_string (bfd_uint64_t idx ATTRIBUTE_UNUSED,
                     struct comp_unit * unit ATTRIBUTE_UNUSED)
{
  /* FIXME: Add support for indexed strings.  */
  return "<indexed strings not yet supported>";
}

/* Read and fill in the value of attribute ATTR as described by FORM.
   Read data starting from INFO_PTR, but never at or beyond INFO_PTR_END.
   Returns an updated INFO_PTR taking into account the amount of data read.  */

static bfd_byte *
read_attribute_value (struct attribute *  attr,
                      unsigned            form,
                      bfd_vma             implicit_const,
                      struct comp_unit *  unit,
                      bfd_byte *          info_ptr,
                      bfd_byte *          info_ptr_end)
{
  bfd *abfd = unit->abfd;
  size_t amt;

  if (info_ptr >= info_ptr_end && form != DW_FORM_flag_present)
    {
      _bfd_error_handler (_("DWARF error: info pointer extends beyond end of attributes"));
      bfd_set_error (bfd_error_bad_value);
      return info_ptr;
    }

  attr->form = (enum dwarf_form) form;

  switch (form)
    {
    case DW_FORM_flag_present:
      attr->u.val = 1;
      break;
    case DW_FORM_ref_addr:
      /* DW_FORM_ref_addr is an address in DWARF2, and an offset in
         DWARF3.  */
      if (unit->version >= 3)
        {
          if (unit->offset_size == 4)
            attr->u.val = read_4_bytes (unit->abfd, &info_ptr, info_ptr_end);
          else
            attr->u.val = read_8_bytes (unit->abfd, &info_ptr, info_ptr_end);
          break;
        }
      /* FALLTHROUGH */
    case DW_FORM_addr:
      attr->u.val = read_address (unit, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_GNU_ref_alt:
    case DW_FORM_sec_offset:
      if (unit->offset_size == 4)
        attr->u.val = read_4_bytes (unit->abfd, &info_ptr, info_ptr_end);
      else
        attr->u.val = read_8_bytes (unit->abfd, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_block2:
      amt = read_2_bytes (abfd, &info_ptr, info_ptr_end);
      attr->u.blk = read_blk (abfd, &info_ptr, info_ptr_end, amt);
      if (attr->u.blk == NULL)
        return NULL;
      break;
    case DW_FORM_block4:
      amt = read_4_bytes (abfd, &info_ptr, info_ptr_end);
      attr->u.blk = read_blk (abfd, &info_ptr, info_ptr_end, amt);
      if (attr->u.blk == NULL)
        return NULL;
      break;
    case DW_FORM_ref1:
    case DW_FORM_flag:
    case DW_FORM_data1:
    case DW_FORM_addrx1:
      attr->u.val = read_1_byte (abfd, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_data2:
    case DW_FORM_ref2:
      attr->u.val = read_2_bytes (abfd, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_addrx3:
      attr->u.val = read_3_bytes (abfd, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_ref4:
    case DW_FORM_data4:
    case DW_FORM_addrx4:
      attr->u.val = read_4_bytes (abfd, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_data8:
    case DW_FORM_ref8:
    case DW_FORM_ref_sig8:
      attr->u.val = read_8_bytes (abfd, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_string:
      attr->u.str = read_string (&info_ptr, info_ptr_end);
      break;
    case DW_FORM_strp:
      attr->u.str = read_indirect_string (unit, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_line_strp:
      attr->u.str = read_indirect_line_string (unit, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_GNU_strp_alt:
      attr->u.str = read_alt_indirect_string (unit, &info_ptr, info_ptr_end);
      break;
    case DW_FORM_strx1:
      attr->u.val = read_1_byte (abfd, &info_ptr, info_ptr_end);
      attr->u.str = (char *) read_indexed_string (attr->u.val, unit);
      break;
    case DW_FORM_strx2:
      attr->u.val = read_2_bytes (abfd, &info_ptr, info_ptr_end);
      attr->u.str = (char *) read_indexed_string (attr->u.val, unit);
      break;
    case DW_FORM_strx3:
      attr->u.val = read_3_bytes (abfd, &info_ptr, info_ptr_end);
      attr->u.str = (char *) read_indexed_string (attr->u.val, unit);
      break;
    case DW_FORM_strx4:
      attr->u.val = read_4_bytes (abfd, &info_ptr, info_ptr_end);
      attr->u.str = (char *) read_indexed_string (attr->u.val, unit);
      break;
    case DW_FORM_strx:
      attr->u.val = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                           false, info_ptr_end);
      attr->u.str = (char *) read_indexed_string (attr->u.val, unit);
      break;
    case DW_FORM_exprloc:
    case DW_FORM_block:
      amt = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                   false, info_ptr_end);
      attr->u.blk = read_blk (abfd, &info_ptr, info_ptr_end, amt);
      if (attr->u.blk == NULL)
        return NULL;
      break;
    case DW_FORM_block1:
      amt = read_1_byte (abfd, &info_ptr, info_ptr_end);
      attr->u.blk = read_blk (abfd, &info_ptr, info_ptr_end, amt);
      if (attr->u.blk == NULL)
        return NULL;
      break;
    case DW_FORM_sdata:
      attr->u.sval = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                            true, info_ptr_end);
      break;
    case DW_FORM_ref_udata:
    case DW_FORM_udata:
    case DW_FORM_addrx:
      attr->u.val = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                           false, info_ptr_end);
      break;
    case DW_FORM_indirect:
      form = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                    false, info_ptr_end);
      if (form == DW_FORM_implicit_const)
        implicit_const = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                                true, info_ptr_end);
      info_ptr = read_attribute_value (attr, form, implicit_const, unit,
                                       info_ptr, info_ptr_end);
      break;
    case DW_FORM_implicit_const:
      attr->form = DW_FORM_sdata;
      attr->u.sval = implicit_const;
      break;
    case DW_FORM_data16:
      /* This is really a "constant", but there is no way to store that
         so pretend it is a 16 byte block instead.  */
      attr->u.blk = read_blk (abfd, &info_ptr, info_ptr_end, 16);
      if (attr->u.blk == NULL)
        return NULL;
      break;

    default:
      _bfd_error_handler (_("DWARF error: invalid or unhandled FORM value: %#x"),
                          form);
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }
  return info_ptr;
}

/* Read an attribute described by an abbreviated attribute.  */

static bfd_byte *
read_attribute (struct attribute *    attr,
                struct attr_abbrev *  abbrev,
                struct comp_unit *    unit,
                bfd_byte *            info_ptr,
                bfd_byte *            info_ptr_end)
{
  attr->name = abbrev->name;
  info_ptr = read_attribute_value (attr, abbrev->form, abbrev->implicit_const,
                                   unit, info_ptr, info_ptr_end);
  return info_ptr;
}

/* Return whether DW_AT_name will return the same as DW_AT_linkage_name
   for a function.  */

static bool
non_mangled (int lang)
{
  switch (lang)
    {
    default:
      return false;

    case DW_LANG_C89:
    case DW_LANG_C:
    case DW_LANG_Ada83:
    case DW_LANG_Cobol74:
    case DW_LANG_Cobol85:
    case DW_LANG_Fortran77:
    case DW_LANG_Pascal83:
    case DW_LANG_C99:
    case DW_LANG_Ada95:
    case DW_LANG_PLI:
    case DW_LANG_UPC:
    case DW_LANG_C11:
      return true;
    }
}

/* Source line information table routines.  */

#define FILE_ALLOC_CHUNK 5
#define DIR_ALLOC_CHUNK 5

struct line_info
{
  struct line_info *    prev_line;
  bfd_vma               address;
  char *                filename;
  unsigned int          line;
  unsigned int          column;
  unsigned int          discriminator;
  unsigned char         op_index;
  unsigned char         end_sequence;           /* End of (sequential) code sequence.  */
};

struct fileinfo
{
  char *                name;
  unsigned int          dir;
  unsigned int          time;
  unsigned int          size;
};

struct line_sequence
{
  bfd_vma               low_pc;
  struct line_sequence* prev_sequence;
  struct line_info*     last_line;  /* Largest VMA.  */
  struct line_info**    line_info_lookup;
  bfd_size_type         num_lines;
};

struct line_info_table
{
  bfd *                 abfd;
  unsigned int          num_files;
  unsigned int          num_dirs;
  unsigned int          num_sequences;
  char *                comp_dir;
  char **               dirs;
  struct fileinfo*      files;
  struct line_sequence* sequences;
  struct line_info*     lcl_head;   /* Local head; used in 'add_line_info'.  */
};

/* Remember some information about each function.  If the function is
   inlined (DW_TAG_inlined_subroutine) it may have two additional
   attributes, DW_AT_call_file and DW_AT_call_line, which specify the
   source code location where this function was inlined.  */

struct funcinfo
{
  /* Pointer to previous function in list of all functions.  */
  struct funcinfo *     prev_func;
  /* Pointer to function one scope higher.  */
  struct funcinfo *     caller_func;
  /* Source location file name where caller_func inlines this func.  */
  char *                caller_file;
  /* Source location file name.  */
  char *                file;
  /* Source location line number where caller_func inlines this func.  */
  int                   caller_line;
  /* Source location line number.  */
  int                   line;
  int                   tag;
  bool                  is_linkage;
  const char *          name;
  struct arange         arange;
  /* Where the symbol is defined.  */
  asection *            sec;
  /* The offset of the funcinfo from the start of the unit.  */
  bfd_uint64_t          unit_offset;
};

struct lookup_funcinfo
{
  /* Function information corresponding to this lookup table entry.  */
  struct funcinfo *     funcinfo;

  /* The lowest address for this specific function.  */
  bfd_vma               low_addr;

  /* The highest address of this function before the lookup table is sorted.
     The highest address of all prior functions after the lookup table is
     sorted, which is used for binary search.  */
  bfd_vma               high_addr;
  /* Index of this function, used to ensure qsort is stable.  */
  unsigned int idx;
};

struct varinfo
{
  /* Pointer to previous variable in list of all variables.  */
  struct varinfo *prev_var;
  /* The offset of the varinfo from the start of the unit.  */
  bfd_uint64_t unit_offset;
  /* Source location file name.  */
  char *file;
  /* Source location line number.  */
  int line;
  /* The type of this variable.  */
  int tag;
  /* The name of the variable, if it has one.  */
  char *name;
  /* The address of the variable.  */
  bfd_vma addr;
  /* Where the symbol is defined.  */
  asection *sec;
  /* Is this a stack variable?  */
  bool stack;
};

/* Return TRUE if NEW_LINE should sort after LINE.  */

static inline bool
new_line_sorts_after (struct line_info *new_line, struct line_info *line)
{
  return (new_line->address > line->address
          || (new_line->address == line->address
              && new_line->op_index > line->op_index));
}


/* Adds a new entry to the line_info list in the line_info_table, ensuring
   that the list is sorted.  Note that the line_info list is sorted from
   highest to lowest VMA (with possible duplicates); that is,
   line_info->prev_line always accesses an equal or smaller VMA.  */

static bool
add_line_info (struct line_info_table *table,
               bfd_vma address,
               unsigned char op_index,
               char *filename,
               unsigned int line,
               unsigned int column,
               unsigned int discriminator,
               int end_sequence)
{
  size_t amt = sizeof (struct line_info);
  struct line_sequence* seq = table->sequences;
  struct line_info* info = (struct line_info *) bfd_alloc (table->abfd, amt);

  if (info == NULL)
    return false;

  /* Set member data of 'info'.  */
  info->prev_line = NULL;
  info->address = address;
  info->op_index = op_index;
  info->line = line;
  info->column = column;
  info->discriminator = discriminator;
  info->end_sequence = end_sequence;

  if (filename && filename[0])
    {
      info->filename = (char *) bfd_alloc (table->abfd, strlen (filename) + 1);
      if (info->filename == NULL)
        return false;
      strcpy (info->filename, filename);
    }
  else
    info->filename = NULL;

  /* Find the correct location for 'info'.  Normally we will receive
     new line_info data 1) in order and 2) with increasing VMAs.
     However some compilers break the rules (cf. decode_line_info) and
     so we include some heuristics for quickly finding the correct
     location for 'info'. In particular, these heuristics optimize for
     the common case in which the VMA sequence that we receive is a
     list of locally sorted VMAs such as
       p...z a...j  (where a < j < p < z)

     Note: table->lcl_head is used to head an *actual* or *possible*
     sub-sequence within the list (such as a...j) that is not directly
     headed by table->last_line

     Note: we may receive duplicate entries from 'decode_line_info'.  */

  if (seq
      && seq->last_line->address == address
      && seq->last_line->op_index == op_index
      && seq->last_line->end_sequence == end_sequence)
    {
      /* We only keep the last entry with the same address and end
         sequence.  See PR ld/4986.  */
      if (table->lcl_head == seq->last_line)
        table->lcl_head = info;
      info->prev_line = seq->last_line->prev_line;
      seq->last_line = info;
    }
  else if (!seq || seq->last_line->end_sequence)
    {
      /* Start a new line sequence.  */
      amt = sizeof (struct line_sequence);
      seq = (struct line_sequence *) bfd_malloc (amt);
      if (seq == NULL)
        return false;
      seq->low_pc = address;
      seq->prev_sequence = table->sequences;
      seq->last_line = info;
      table->lcl_head = info;
      table->sequences = seq;
      table->num_sequences++;
    }
  else if (info->end_sequence
           || new_line_sorts_after (info, seq->last_line))
    {
      /* Normal case: add 'info' to the beginning of the current sequence.  */
      info->prev_line = seq->last_line;
      seq->last_line = info;

      /* lcl_head: initialize to head a *possible* sequence at the end.  */
      if (!table->lcl_head)
        table->lcl_head = info;
    }
  else if (!new_line_sorts_after (info, table->lcl_head)
           && (!table->lcl_head->prev_line
               || new_line_sorts_after (info, table->lcl_head->prev_line)))
    {
      /* Abnormal but easy: lcl_head is the head of 'info'.  */
      info->prev_line = table->lcl_head->prev_line;
      table->lcl_head->prev_line = info;
    }
  else
    {
      /* Abnormal and hard: Neither 'last_line' nor 'lcl_head'
         are valid heads for 'info'.  Reset 'lcl_head'.  */
      struct line_info* li2 = seq->last_line; /* Always non-NULL.  */
      struct line_info* li1 = li2->prev_line;

      while (li1)
        {
          if (!new_line_sorts_after (info, li2)
              && new_line_sorts_after (info, li1))
            break;

          li2 = li1; /* always non-NULL */
          li1 = li1->prev_line;
        }
      table->lcl_head = li2;
      info->prev_line = table->lcl_head->prev_line;
      table->lcl_head->prev_line = info;
      if (address < seq->low_pc)
        seq->low_pc = address;
    }
  return true;
}

/* Extract a fully qualified filename from a line info table.
   The returned string has been malloc'ed and it is the caller's
   responsibility to free it.  */

static char *
concat_filename (struct line_info_table *table, unsigned int file)
{
  char *filename;

  if (table == NULL || file - 1 >= table->num_files)
    {
      /* FILE == 0 means unknown.  */
      if (file)
        _bfd_error_handler
          (_("DWARF error: mangled line number section (bad file number)"));
      return strdup ("<unknown>");
    }

  filename = table->files[file - 1].name;
  if (filename == NULL)
    return strdup ("<unknown>");

  if (!IS_ABSOLUTE_PATH (filename))
    {
      char *dir_name = NULL;
      char *subdir_name = NULL;
      char *name;
      size_t len;

      if (table->files[file - 1].dir
          /* PR 17512: file: 0317e960.  */
          && table->files[file - 1].dir <= table->num_dirs
          /* PR 17512: file: 7f3d2e4b.  */
          && table->dirs != NULL)
        subdir_name = table->dirs[table->files[file - 1].dir - 1];

      if (!subdir_name || !IS_ABSOLUTE_PATH (subdir_name))
        dir_name = table->comp_dir;

      if (!dir_name)
        {
          dir_name = subdir_name;
          subdir_name = NULL;
        }

      if (!dir_name)
        return strdup (filename);

      len = strlen (dir_name) + strlen (filename) + 2;

      if (subdir_name)
        {
          len += strlen (subdir_name) + 1;
          name = (char *) bfd_malloc (len);
          if (name)
            sprintf (name, "%s/%s/%s", dir_name, subdir_name, filename);
        }
      else
        {
          name = (char *) bfd_malloc (len);
          if (name)
            sprintf (name, "%s/%s", dir_name, filename);
        }

      return name;
    }

  return strdup (filename);
}

static bool
arange_add (const struct comp_unit *unit, struct arange *first_arange,
            bfd_vma low_pc, bfd_vma high_pc)
{
  struct arange *arange;

  /* Ignore empty ranges.  */
  if (low_pc == high_pc)
    return true;

  /* If the first arange is empty, use it.  */
  if (first_arange->high == 0)
    {
      first_arange->low = low_pc;
      first_arange->high = high_pc;
      return true;
    }

  /* Next see if we can cheaply extend an existing range.  */
  arange = first_arange;
  do
    {
      if (low_pc == arange->high)
        {
          arange->high = high_pc;
          return true;
        }
      if (high_pc == arange->low)
        {
          arange->low = low_pc;
          return true;
        }
      arange = arange->next;
    }
  while (arange);

  /* Need to allocate a new arange and insert it into the arange list.
     Order isn't significant, so just insert after the first arange.  */
  arange = (struct arange *) bfd_alloc (unit->abfd, sizeof (*arange));
  if (arange == NULL)
    return false;
  arange->low = low_pc;
  arange->high = high_pc;
  arange->next = first_arange->next;
  first_arange->next = arange;
  return true;
}

/* Compare function for line sequences.  */

static int
compare_sequences (const void* a, const void* b)
{
  const struct line_sequence* seq1 = a;
  const struct line_sequence* seq2 = b;

  /* Sort by low_pc as the primary key.  */
  if (seq1->low_pc < seq2->low_pc)
    return -1;
  if (seq1->low_pc > seq2->low_pc)
    return 1;

  /* If low_pc values are equal, sort in reverse order of
     high_pc, so that the largest region comes first.  */
  if (seq1->last_line->address < seq2->last_line->address)
    return 1;
  if (seq1->last_line->address > seq2->last_line->address)
    return -1;

  if (seq1->last_line->op_index < seq2->last_line->op_index)
    return 1;
  if (seq1->last_line->op_index > seq2->last_line->op_index)
    return -1;

  /* num_lines is initially an index, to make the sort stable.  */
  if (seq1->num_lines < seq2->num_lines)
    return -1;
  if (seq1->num_lines > seq2->num_lines)
    return 1;
  return 0;
}

/* Construct the line information table for quick lookup.  */

static bool
build_line_info_table (struct line_info_table *  table,
                       struct line_sequence *    seq)
{
  size_t amt;
  struct line_info **line_info_lookup;
  struct line_info *each_line;
  unsigned int num_lines;
  unsigned int line_index;

  if (seq->line_info_lookup != NULL)
    return true;

  /* Count the number of line information entries.  We could do this while
     scanning the debug information, but some entries may be added via
     lcl_head without having a sequence handy to increment the number of
     lines.  */
  num_lines = 0;
  for (each_line = seq->last_line; each_line; each_line = each_line->prev_line)
    num_lines++;

  seq->num_lines = num_lines;
  if (num_lines == 0)
    return true;

  /* Allocate space for the line information lookup table.  */
  amt = sizeof (struct line_info*) * num_lines;
  line_info_lookup = (struct line_info**) bfd_alloc (table->abfd, amt);
  seq->line_info_lookup = line_info_lookup;
  if (line_info_lookup == NULL)
    return false;

  /* Create the line information lookup table.  */
  line_index = num_lines;
  for (each_line = seq->last_line; each_line; each_line = each_line->prev_line)
    line_info_lookup[--line_index] = each_line;

  BFD_ASSERT (line_index == 0);
  return true;
}

/* Sort the line sequences for quick lookup.  */

static bool
sort_line_sequences (struct line_info_table* table)
{
  size_t amt;
  struct line_sequence *sequences;
  struct line_sequence *seq;
  unsigned int n = 0;
  unsigned int num_sequences = table->num_sequences;
  bfd_vma last_high_pc;

  if (num_sequences == 0)
    return true;

  /* Allocate space for an array of sequences.  */
  amt = sizeof (struct line_sequence) * num_sequences;
  sequences = (struct line_sequence *) bfd_alloc (table->abfd, amt);
  if (sequences == NULL)
    return false;

  /* Copy the linked list into the array, freeing the original nodes.  */
  seq = table->sequences;
  for (n = 0; n < num_sequences; n++)
    {
      struct line_sequence* last_seq = seq;

      BFD_ASSERT (seq);
      sequences[n].low_pc = seq->low_pc;
      sequences[n].prev_sequence = NULL;
      sequences[n].last_line = seq->last_line;
      sequences[n].line_info_lookup = NULL;
      sequences[n].num_lines = n;
      seq = seq->prev_sequence;
      free (last_seq);
    }
  BFD_ASSERT (seq == NULL);

  qsort (sequences, n, sizeof (struct line_sequence), compare_sequences);

  /* Make the list binary-searchable by trimming overlapping entries
     and removing nested entries.  */
  num_sequences = 1;
  last_high_pc = sequences[0].last_line->address;
  for (n = 1; n < table->num_sequences; n++)
    {
      if (sequences[n].low_pc < last_high_pc)
        {
          if (sequences[n].last_line->address <= last_high_pc)
            /* Skip nested entries.  */
            continue;

          /* Trim overlapping entries.  */
          sequences[n].low_pc = last_high_pc;
        }
      last_high_pc = sequences[n].last_line->address;
      if (n > num_sequences)
        {
          /* Close up the gap.  */
          sequences[num_sequences].low_pc = sequences[n].low_pc;
          sequences[num_sequences].last_line = sequences[n].last_line;
        }
      num_sequences++;
    }

  table->sequences = sequences;
  table->num_sequences = num_sequences;
  return true;
}

/* Add directory to TABLE.  CUR_DIR memory ownership is taken by TABLE.  */

static bool
line_info_add_include_dir (struct line_info_table *table, char *cur_dir)
{
  if ((table->num_dirs % DIR_ALLOC_CHUNK) == 0)
    {
      char **tmp;
      size_t amt;

      amt = table->num_dirs + DIR_ALLOC_CHUNK;
      amt *= sizeof (char *);

      tmp = (char **) bfd_realloc (table->dirs, amt);
      if (tmp == NULL)
        return false;
      table->dirs = tmp;
    }

  table->dirs[table->num_dirs++] = cur_dir;
  return true;
}

static bool
line_info_add_include_dir_stub (struct line_info_table *table, char *cur_dir,
                                unsigned int dir ATTRIBUTE_UNUSED,
                                unsigned int xtime ATTRIBUTE_UNUSED,
                                unsigned int size ATTRIBUTE_UNUSED)
{
  return line_info_add_include_dir (table, cur_dir);
}

/* Add file to TABLE.  CUR_FILE memory ownership is taken by TABLE.  */

static bool
line_info_add_file_name (struct line_info_table *table, char *cur_file,
                         unsigned int dir, unsigned int xtime,
                         unsigned int size)
{
  if ((table->num_files % FILE_ALLOC_CHUNK) == 0)
    {
      struct fileinfo *tmp;
      size_t amt;

      amt = table->num_files + FILE_ALLOC_CHUNK;
      amt *= sizeof (struct fileinfo);

      tmp = (struct fileinfo *) bfd_realloc (table->files, amt);
      if (tmp == NULL)
        return false;
      table->files = tmp;
    }

  table->files[table->num_files].name = cur_file;
  table->files[table->num_files].dir = dir;
  table->files[table->num_files].time = xtime;
  table->files[table->num_files].size = size;
  table->num_files++;
  return true;
}

/* Read directory or file name entry format, starting with byte of
   format count entries, ULEB128 pairs of entry formats, ULEB128 of
   entries count and the entries themselves in the described entry
   format.  */

static bool
read_formatted_entries (struct comp_unit *unit, bfd_byte **bufp,
                        bfd_byte *buf_end, struct line_info_table *table,
                        bool (*callback) (struct line_info_table *table,
                                          char *cur_file,
                                          unsigned int dir,
                                          unsigned int time,
                                          unsigned int size))
{
  bfd *abfd = unit->abfd;
  bfd_byte format_count, formati;
  bfd_vma data_count, datai;
  bfd_byte *buf = *bufp;
  bfd_byte *format_header_data;

  format_count = read_1_byte (abfd, &buf, buf_end);
  format_header_data = buf;
  for (formati = 0; formati < format_count; formati++)
    {
      _bfd_safe_read_leb128 (abfd, &buf, false, buf_end);
      _bfd_safe_read_leb128 (abfd, &buf, false, buf_end);
    }

  data_count = _bfd_safe_read_leb128 (abfd, &buf, false, buf_end);
  if (format_count == 0 && data_count != 0)
    {
      _bfd_error_handler (_("DWARF error: zero format count"));
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  /* PR 22210.  Paranoia check.  Don't bother running the loop
     if we know that we are going to run out of buffer.  */
  if (data_count > (bfd_vma) (buf_end - buf))
    {
      _bfd_error_handler
        (_("DWARF error: data count (%" PRIx64 ") larger than buffer size"),
         (uint64_t) data_count);
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  for (datai = 0; datai < data_count; datai++)
    {
      bfd_byte *format = format_header_data;
      struct fileinfo fe;

      memset (&fe, 0, sizeof fe);
      for (formati = 0; formati < format_count; formati++)
        {
          bfd_vma content_type, form;
          char *string_trash;
          char **stringp = &string_trash;
          unsigned int uint_trash, *uintp = &uint_trash;
          struct attribute attr;

          content_type = _bfd_safe_read_leb128 (abfd, &format, false, buf_end);
          switch (content_type)
            {
            case DW_LNCT_path:
              stringp = &fe.name;
              break;
            case DW_LNCT_directory_index:
              uintp = &fe.dir;
              break;
            case DW_LNCT_timestamp:
              uintp = &fe.time;
              break;
            case DW_LNCT_size:
              uintp = &fe.size;
              break;
            case DW_LNCT_MD5:
              break;
            default:
              _bfd_error_handler
                (_("DWARF error: unknown format content type %" PRIu64),
                 (uint64_t) content_type);
              bfd_set_error (bfd_error_bad_value);
              return false;
            }

          form = _bfd_safe_read_leb128 (abfd, &format, false, buf_end);
          buf = read_attribute_value (&attr, form, 0, unit, buf, buf_end);
          if (buf == NULL)
            return false;
          switch (form)
            {
            case DW_FORM_string:
            case DW_FORM_line_strp:
              *stringp = attr.u.str;
              break;

            case DW_FORM_data1:
            case DW_FORM_data2:
            case DW_FORM_data4:
            case DW_FORM_data8:
            case DW_FORM_udata:
              *uintp = attr.u.val;
              break;

            case DW_FORM_data16:
              /* MD5 data is in the attr.blk, but we are ignoring those.  */
              break;
            }
        }

      /* Skip the first "zero entry", which is the compilation dir/file.  */
      if (datai != 0)
        if (!callback (table, fe.name, fe.dir, fe.time, fe.size))
          return false;
    }

  *bufp = buf;
  return true;
}

/* Decode the line number information for UNIT.  */

static struct line_info_table*
decode_line_info (struct comp_unit *unit)
{
  bfd *abfd = unit->abfd;
  struct dwarf2_debug *stash = unit->stash;
  struct dwarf2_debug_file *file = unit->file;
  struct line_info_table* table;
  bfd_byte *line_ptr;
  bfd_byte *line_end;
  struct line_head lh;
  unsigned int i, offset_size;
  char *cur_file, *cur_dir;
  unsigned char op_code, extended_op, adj_opcode;
  unsigned int exop_len;
  size_t amt;

  if (unit->line_offset == 0 && file->line_table)
    return file->line_table;

  if (! read_section (abfd, &stash->debug_sections[debug_line],
                      file->syms, unit->line_offset,
                      &file->dwarf_line_buffer, &file->dwarf_line_size))
    return NULL;

  if (file->dwarf_line_size < 16)
    {
      _bfd_error_handler
        (_("DWARF error: line info section is too small (%" PRId64 ")"),
         (int64_t) file->dwarf_line_size);
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }
  line_ptr = file->dwarf_line_buffer + unit->line_offset;
  line_end = file->dwarf_line_buffer + file->dwarf_line_size;

  /* Read in the prologue.  */
  lh.total_length = read_4_bytes (abfd, &line_ptr, line_end);
  offset_size = 4;
  if (lh.total_length == 0xffffffff)
    {
      lh.total_length = read_8_bytes (abfd, &line_ptr, line_end);
      offset_size = 8;
    }
  else if (lh.total_length == 0 && unit->addr_size == 8)
    {
      /* Handle (non-standard) 64-bit DWARF2 formats.  */
      lh.total_length = read_4_bytes (abfd, &line_ptr, line_end);
      offset_size = 8;
    }

  if (lh.total_length > (size_t) (line_end - line_ptr))
    {
      _bfd_error_handler
        /* xgettext: c-format */
        (_("DWARF error: line info data is bigger (%#" PRIx64 ")"
           " than the space remaining in the section (%#lx)"),
         (uint64_t) lh.total_length, (unsigned long) (line_end - line_ptr));
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  line_end = line_ptr + lh.total_length;

  lh.version = read_2_bytes (abfd, &line_ptr, line_end);
  if (lh.version < 2 || lh.version > 5)
    {
      _bfd_error_handler
        (_("DWARF error: unhandled .debug_line version %d"), lh.version);
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  if (line_ptr + offset_size + (lh.version >= 5 ? 8 : (lh.version >= 4 ? 6 : 5))
      >= line_end)
    {
      _bfd_error_handler
        (_("DWARF error: ran out of room reading prologue"));
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  if (lh.version >= 5)
    {
      unsigned int segment_selector_size;

      /* Skip address size.  */
      read_1_byte (abfd, &line_ptr, line_end);

      segment_selector_size = read_1_byte (abfd, &line_ptr, line_end);
      if (segment_selector_size != 0)
        {
          _bfd_error_handler
            (_("DWARF error: line info unsupported segment selector size %u"),
             segment_selector_size);
          bfd_set_error (bfd_error_bad_value);
          return NULL;
        }
    }

  if (offset_size == 4)
    lh.prologue_length = read_4_bytes (abfd, &line_ptr, line_end);
  else
    lh.prologue_length = read_8_bytes (abfd, &line_ptr, line_end);

  lh.minimum_instruction_length = read_1_byte (abfd, &line_ptr, line_end);

  if (lh.version >= 4)
    lh.maximum_ops_per_insn = read_1_byte (abfd, &line_ptr, line_end);
  else
    lh.maximum_ops_per_insn = 1;

  if (lh.maximum_ops_per_insn == 0)
    {
      _bfd_error_handler
        (_("DWARF error: invalid maximum operations per instruction"));
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  lh.default_is_stmt = read_1_byte (abfd, &line_ptr, line_end);
  lh.line_base = read_1_signed_byte (abfd, &line_ptr, line_end);
  lh.line_range = read_1_byte (abfd, &line_ptr, line_end);
  lh.opcode_base = read_1_byte (abfd, &line_ptr, line_end);

  if (line_ptr + (lh.opcode_base - 1) >= line_end)
    {
      _bfd_error_handler (_("DWARF error: ran out of room reading opcodes"));
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  amt = lh.opcode_base * sizeof (unsigned char);
  lh.standard_opcode_lengths = (unsigned char *) bfd_alloc (abfd, amt);

  lh.standard_opcode_lengths[0] = 1;

  for (i = 1; i < lh.opcode_base; ++i)
    lh.standard_opcode_lengths[i] = read_1_byte (abfd, &line_ptr, line_end);

  amt = sizeof (struct line_info_table);
  table = (struct line_info_table *) bfd_alloc (abfd, amt);
  if (table == NULL)
    return NULL;
  table->abfd = abfd;
  table->comp_dir = unit->comp_dir;

  table->num_files = 0;
  table->files = NULL;

  table->num_dirs = 0;
  table->dirs = NULL;

  table->num_sequences = 0;
  table->sequences = NULL;

  table->lcl_head = NULL;

  if (lh.version >= 5)
    {
      /* Read directory table.  */
      if (!read_formatted_entries (unit, &line_ptr, line_end, table,
                                   line_info_add_include_dir_stub))
        goto fail;

      /* Read file name table.  */
      if (!read_formatted_entries (unit, &line_ptr, line_end, table,
                                   line_info_add_file_name))
        goto fail;
    }
  else
    {
      /* Read directory table.  */
      while ((cur_dir = read_string (&line_ptr, line_end)) != NULL)
        {
          if (!line_info_add_include_dir (table, cur_dir))
            goto fail;
        }

      /* Read file name table.  */
      while ((cur_file = read_string (&line_ptr, line_end)) != NULL)
        {
          unsigned int dir, xtime, size;

          dir = _bfd_safe_read_leb128 (abfd, &line_ptr, false, line_end);
          xtime = _bfd_safe_read_leb128 (abfd, &line_ptr, false, line_end);
          size = _bfd_safe_read_leb128 (abfd, &line_ptr, false, line_end);

          if (!line_info_add_file_name (table, cur_file, dir, xtime, size))
            goto fail;
        }
    }

  /* Read the statement sequences until there's nothing left.  */
  while (line_ptr < line_end)
    {
      /* State machine registers.  */
      bfd_vma address = 0;
      unsigned char op_index = 0;
      char * filename = table->num_files ? concat_filename (table, 1) : NULL;
      unsigned int line = 1;
      unsigned int column = 0;
      unsigned int discriminator = 0;
      int is_stmt = lh.default_is_stmt;
      int end_sequence = 0;
      unsigned int dir, xtime, size;
      /* eraxxon@alumni.rice.edu: Against the DWARF2 specs, some
         compilers generate address sequences that are wildly out of
         order using DW_LNE_set_address (e.g. Intel C++ 6.0 compiler
         for ia64-Linux).  Thus, to determine the low and high
         address, we must compare on every DW_LNS_copy, etc.  */
      bfd_vma low_pc  = (bfd_vma) -1;
      bfd_vma high_pc = 0;

      /* Decode the table.  */
      while (!end_sequence && line_ptr < line_end)
        {
          op_code = read_1_byte (abfd, &line_ptr, line_end);

          if (op_code >= lh.opcode_base)
            {
              /* Special operand.  */
              adj_opcode = op_code - lh.opcode_base;
              if (lh.line_range == 0)
                goto line_fail;
              if (lh.maximum_ops_per_insn == 1)
                address += (adj_opcode / lh.line_range
                            * lh.minimum_instruction_length);
              else
                {
                  address += ((op_index + adj_opcode / lh.line_range)
                              / lh.maximum_ops_per_insn
                              * lh.minimum_instruction_length);
                  op_index = ((op_index + adj_opcode / lh.line_range)
                              % lh.maximum_ops_per_insn);
                }
              line += lh.line_base + (adj_opcode % lh.line_range);
              /* Append row to matrix using current values.  */
              if (!add_line_info (table, address, op_index, filename,
                                  line, column, discriminator, 0))
                goto line_fail;
              discriminator = 0;
              if (address < low_pc)
                low_pc = address;
              if (address > high_pc)
                high_pc = address;
            }
          else switch (op_code)
            {
            case DW_LNS_extended_op:
              exop_len = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                                false, line_end);
              extended_op = read_1_byte (abfd, &line_ptr, line_end);

              switch (extended_op)
                {
                case DW_LNE_end_sequence:
                  end_sequence = 1;
                  if (!add_line_info (table, address, op_index, filename, line,
                                      column, discriminator, end_sequence))
                    goto line_fail;
                  discriminator = 0;
                  if (address < low_pc)
                    low_pc = address;
                  if (address > high_pc)
                    high_pc = address;
                  if (!arange_add (unit, &unit->arange, low_pc, high_pc))
                    goto line_fail;
                  break;
                case DW_LNE_set_address:
                  address = read_address (unit, &line_ptr, line_end);
                  op_index = 0;
                  break;
                case DW_LNE_define_file:
                  cur_file = read_string (&line_ptr, line_end);
                  dir = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                               false, line_end);
                  xtime = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                                 false, line_end);
                  size = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                                false, line_end);
                  if (!line_info_add_file_name (table, cur_file, dir,
                                                xtime, size))
                    goto line_fail;
                  break;
                case DW_LNE_set_discriminator:
                  discriminator =
                    _bfd_safe_read_leb128 (abfd, &line_ptr,
                                           false, line_end);
                  break;
                case DW_LNE_HP_source_file_correlation:
                  line_ptr += exop_len - 1;
                  break;
                default:
                  _bfd_error_handler
                    (_("DWARF error: mangled line number section"));
                  bfd_set_error (bfd_error_bad_value);
                line_fail:
                  free (filename);
                  goto fail;
                }
              break;
            case DW_LNS_copy:
              if (!add_line_info (table, address, op_index,
                                  filename, line, column, discriminator, 0))
                goto line_fail;
              discriminator = 0;
              if (address < low_pc)
                low_pc = address;
              if (address > high_pc)
                high_pc = address;
              break;
            case DW_LNS_advance_pc:
              if (lh.maximum_ops_per_insn == 1)
                address += (lh.minimum_instruction_length
                            * _bfd_safe_read_leb128 (abfd, &line_ptr,
                                                     false, line_end));
              else
                {
                  bfd_vma adjust = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                                          false, line_end);
                  address = ((op_index + adjust) / lh.maximum_ops_per_insn
                             * lh.minimum_instruction_length);
                  op_index = (op_index + adjust) % lh.maximum_ops_per_insn;
                }
              break;
            case DW_LNS_advance_line:
              line += _bfd_safe_read_leb128 (abfd, &line_ptr,
                                             true, line_end);
              break;
            case DW_LNS_set_file:
              {
                unsigned int filenum;

                /* The file and directory tables are 0
                   based, the references are 1 based.  */
                filenum = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                                 false, line_end);
                free (filename);
                filename = concat_filename (table, filenum);
                break;
              }
            case DW_LNS_set_column:
              column = _bfd_safe_read_leb128 (abfd, &line_ptr,
                                              false, line_end);
              break;
            case DW_LNS_negate_stmt:
              is_stmt = (!is_stmt);
              break;
            case DW_LNS_set_basic_block:
              break;
            case DW_LNS_const_add_pc:
              if (lh.line_range == 0)
                goto line_fail;
              if (lh.maximum_ops_per_insn == 1)
                address += (lh.minimum_instruction_length
                            * ((255 - lh.opcode_base) / lh.line_range));
              else
                {
                  bfd_vma adjust = ((255 - lh.opcode_base) / lh.line_range);
                  address += (lh.minimum_instruction_length
                              * ((op_index + adjust)
                                 / lh.maximum_ops_per_insn));
                  op_index = (op_index + adjust) % lh.maximum_ops_per_insn;
                }
              break;
            case DW_LNS_fixed_advance_pc:
              address += read_2_bytes (abfd, &line_ptr, line_end);
              op_index = 0;
              break;
            default:
              /* Unknown standard opcode, ignore it.  */
              for (i = 0; i < lh.standard_opcode_lengths[op_code]; i++)
                (void) _bfd_safe_read_leb128 (abfd, &line_ptr,
                                              false, line_end);
              break;
            }
        }

      free (filename);
    }

  if (unit->line_offset == 0)
    file->line_table = table;
  if (sort_line_sequences (table))
    return table;

 fail:
  while (table->sequences != NULL)
    {
      struct line_sequence* seq = table->sequences;
      table->sequences = table->sequences->prev_sequence;
      free (seq);
    }
  free (table->files);
  free (table->dirs);
  return NULL;
}

/* If ADDR is within TABLE set the output parameters and return the
   range of addresses covered by the entry used to fill them out.
   Otherwise set * FILENAME_PTR to NULL and return 0.
   The parameters FILENAME_PTR, LINENUMBER_PTR and DISCRIMINATOR_PTR
   are pointers to the objects to be filled in.  */

static bfd_vma
lookup_address_in_line_info_table (struct line_info_table *table,
                                   bfd_vma addr,
                                   const char **filename_ptr,
                                   unsigned int *linenumber_ptr,
                                   unsigned int *discriminator_ptr)
{
  struct line_sequence *seq = NULL;
  struct line_info *info;
  int low, high, mid;

  /* Binary search the array of sequences.  */
  low = 0;
  high = table->num_sequences;
  while (low < high)
    {
      mid = (low + high) / 2;
      seq = &table->sequences[mid];
      if (addr < seq->low_pc)
        high = mid;
      else if (addr >= seq->last_line->address)
        low = mid + 1;
      else
        break;
    }

  /* Check for a valid sequence.  */
  if (!seq || addr < seq->low_pc || addr >= seq->last_line->address)
    goto fail;

  if (!build_line_info_table (table, seq))
    goto fail;

  /* Binary search the array of line information.  */
  low = 0;
  high = seq->num_lines;
  info = NULL;
  while (low < high)
    {
      mid = (low + high) / 2;
      info = seq->line_info_lookup[mid];
      if (addr < info->address)
        high = mid;
      else if (addr >= seq->line_info_lookup[mid + 1]->address)
        low = mid + 1;
      else
        break;
    }

  /* Check for a valid line information entry.  */
  if (info
      && addr >= info->address
      && addr < seq->line_info_lookup[mid + 1]->address
      && !(info->end_sequence || info == seq->last_line))
    {
      *filename_ptr = info->filename;
      *linenumber_ptr = info->line;
      if (discriminator_ptr)
        *discriminator_ptr = info->discriminator;
      return seq->last_line->address - seq->low_pc;
    }

 fail:
  *filename_ptr = NULL;
  return 0;
}

/* Read in the .debug_ranges section for future reference.  */

static bool
read_debug_ranges (struct comp_unit * unit)
{
  struct dwarf2_debug *stash = unit->stash;
  struct dwarf2_debug_file *file = unit->file;

  return read_section (unit->abfd, &stash->debug_sections[debug_ranges],
                       file->syms, 0,
                       &file->dwarf_ranges_buffer, &file->dwarf_ranges_size);
}

/* Read in the .debug_rnglists section for future reference.  */

static bool
read_debug_rnglists (struct comp_unit * unit)
{
  struct dwarf2_debug *stash = unit->stash;
  struct dwarf2_debug_file *file = unit->file;

  return read_section (unit->abfd, &stash->debug_sections[debug_rnglists],
                       file->syms, 0,
                       &file->dwarf_rnglists_buffer, &file->dwarf_rnglists_size);
}

/* Function table functions.  */

static int
compare_lookup_funcinfos (const void * a, const void * b)
{
  const struct lookup_funcinfo * lookup1 = a;
  const struct lookup_funcinfo * lookup2 = b;

  if (lookup1->low_addr < lookup2->low_addr)
    return -1;
  if (lookup1->low_addr > lookup2->low_addr)
    return 1;
  if (lookup1->high_addr < lookup2->high_addr)
    return -1;
  if (lookup1->high_addr > lookup2->high_addr)
    return 1;

  if (lookup1->idx < lookup2->idx)
    return -1;
  if (lookup1->idx > lookup2->idx)
    return 1;
  return 0;
}

static bool
build_lookup_funcinfo_table (struct comp_unit * unit)
{
  struct lookup_funcinfo *lookup_funcinfo_table = unit->lookup_funcinfo_table;
  unsigned int number_of_functions = unit->number_of_functions;
  struct funcinfo *each;
  struct lookup_funcinfo *entry;
  size_t func_index;
  struct arange *range;
  bfd_vma low_addr, high_addr;

  if (lookup_funcinfo_table || number_of_functions == 0)
    return true;

  /* Create the function info lookup table.  */
  lookup_funcinfo_table = (struct lookup_funcinfo *)
    bfd_malloc (number_of_functions * sizeof (struct lookup_funcinfo));
  if (lookup_funcinfo_table == NULL)
    return false;

  /* Populate the function info lookup table.  */
  func_index = number_of_functions;
  for (each = unit->function_table; each; each = each->prev_func)
    {
      entry = &lookup_funcinfo_table[--func_index];
      entry->funcinfo = each;
      entry->idx = func_index;

      /* Calculate the lowest and highest address for this function entry.  */
      low_addr  = entry->funcinfo->arange.low;
      high_addr = entry->funcinfo->arange.high;

      for (range = entry->funcinfo->arange.next; range; range = range->next)
        {
          if (range->low < low_addr)
            low_addr = range->low;
          if (range->high > high_addr)
            high_addr = range->high;
        }

      entry->low_addr = low_addr;
      entry->high_addr = high_addr;
    }

  BFD_ASSERT (func_index == 0);

  /* Sort the function by address.  */
  qsort (lookup_funcinfo_table,
         number_of_functions,
         sizeof (struct lookup_funcinfo),
         compare_lookup_funcinfos);

  /* Calculate the high watermark for each function in the lookup table.  */
  high_addr = lookup_funcinfo_table[0].high_addr;
  for (func_index = 1; func_index < number_of_functions; func_index++)
    {
      entry = &lookup_funcinfo_table[func_index];
      if (entry->high_addr > high_addr)
        high_addr = entry->high_addr;
      else
        entry->high_addr = high_addr;
    }

  unit->lookup_funcinfo_table = lookup_funcinfo_table;
  return true;
}

/* If ADDR is within UNIT's function tables, set FUNCTION_PTR, and return
   TRUE.  Note that we need to find the function that has the smallest range
   that contains ADDR, to handle inlined functions without depending upon
   them being ordered in TABLE by increasing range.  */

static bool
lookup_address_in_function_table (struct comp_unit *unit,
                                  bfd_vma addr,
                                  struct funcinfo **function_ptr)
{
  unsigned int number_of_functions = unit->number_of_functions;
  struct lookup_funcinfo* lookup_funcinfo = NULL;
  struct funcinfo* funcinfo = NULL;
  struct funcinfo* best_fit = NULL;
  bfd_vma best_fit_len = 0;
  bfd_size_type low, high, mid, first;
  struct arange *arange;

  if (number_of_functions == 0)
    return false;

  if (!build_lookup_funcinfo_table (unit))
    return false;

  if (unit->lookup_funcinfo_table[number_of_functions - 1].high_addr < addr)
    return false;

  /* Find the first function in the lookup table which may contain the
     specified address.  */
  low = 0;
  high = number_of_functions;
  first = high;
  while (low < high)
    {
      mid = (low + high) / 2;
      lookup_funcinfo = &unit->lookup_funcinfo_table[mid];
      if (addr < lookup_funcinfo->low_addr)
        high = mid;
      else if (addr >= lookup_funcinfo->high_addr)
        low = mid + 1;
      else
        high = first = mid;
    }

  /* Find the 'best' match for the address.  The prior algorithm defined the
     best match as the function with the smallest address range containing
     the specified address.  This definition should probably be changed to the
     innermost inline routine containing the address, but right now we want
     to get the same results we did before.  */
  while (first < number_of_functions)
    {
      if (addr < unit->lookup_funcinfo_table[first].low_addr)
        break;
      funcinfo = unit->lookup_funcinfo_table[first].funcinfo;

      for (arange = &funcinfo->arange; arange; arange = arange->next)
        {
          if (addr < arange->low || addr >= arange->high)
            continue;

          if (!best_fit
              || arange->high - arange->low < best_fit_len
              /* The following comparison is designed to return the same
                 match as the previous algorithm for routines which have the
                 same best fit length.  */
              || (arange->high - arange->low == best_fit_len
                  && funcinfo > best_fit))
            {
              best_fit = funcinfo;
              best_fit_len = arange->high - arange->low;
            }
        }

      first++;
    }

  if (!best_fit)
    return false;

  *function_ptr = best_fit;
  return true;
}

/* If SYM at ADDR is within function table of UNIT, set FILENAME_PTR
   and LINENUMBER_PTR, and return TRUE.  */

static bool
lookup_symbol_in_function_table (struct comp_unit *unit,
                                 asymbol *sym,
                                 bfd_vma addr,
                                 const char **filename_ptr,
                                 unsigned int *linenumber_ptr)
{
  struct funcinfo* each_func;
  struct funcinfo* best_fit = NULL;
  bfd_vma best_fit_len = 0;
  struct arange *arange;
  const char *name = bfd_asymbol_name (sym);
  asection *sec = bfd_asymbol_section (sym);

  for (each_func = unit->function_table;
       each_func;
       each_func = each_func->prev_func)
    {
      for (arange = &each_func->arange;
           arange;
           arange = arange->next)
        {
          if ((!each_func->sec || each_func->sec == sec)
              && addr >= arange->low
              && addr < arange->high
              && each_func->name
              && strcmp (name, each_func->name) == 0
              && (!best_fit
                  || arange->high - arange->low < best_fit_len))
            {
              best_fit = each_func;
              best_fit_len = arange->high - arange->low;
            }
        }
    }

  if (best_fit)
    {
      best_fit->sec = sec;
      *filename_ptr = best_fit->file;
      *linenumber_ptr = best_fit->line;
      return true;
    }
  else
    return false;
}

/* Variable table functions.  */

/* If SYM is within variable table of UNIT, set FILENAME_PTR and
   LINENUMBER_PTR, and return TRUE.  */

static bool
lookup_symbol_in_variable_table (struct comp_unit *unit,
                                 asymbol *sym,
                                 bfd_vma addr,
                                 const char **filename_ptr,
                                 unsigned int *linenumber_ptr)
{
  const char *name = bfd_asymbol_name (sym);
  asection *sec = bfd_asymbol_section (sym);
  struct varinfo* each;

  for (each = unit->variable_table; each; each = each->prev_var)
    if (! each->stack
        && each->file != NULL
        && each->name != NULL
        && each->addr == addr
        && (!each->sec || each->sec == sec)
        && strcmp (name, each->name) == 0)
      break;

  if (each)
    {
      each->sec = sec;
      *filename_ptr = each->file;
      *linenumber_ptr = each->line;
      return true;
    }

  return false;
}

static struct comp_unit *stash_comp_unit (struct dwarf2_debug *,
                                          struct dwarf2_debug_file *);
static bool comp_unit_maybe_decode_line_info (struct comp_unit *);

static bool
find_abstract_instance (struct comp_unit *unit,
                        struct attribute *attr_ptr,
                        unsigned int recur_count,
                        const char **pname,
                        bool *is_linkage,
                        char **filename_ptr,
                        int *linenumber_ptr)
{
  bfd *abfd = unit->abfd;
  bfd_byte *info_ptr = NULL;
  bfd_byte *info_ptr_end;
  unsigned int abbrev_number, i;
  struct abbrev_info *abbrev;
  bfd_uint64_t die_ref = attr_ptr->u.val;
  struct attribute attr;
  const char *name = NULL;

  if (recur_count == 100)
    {
      _bfd_error_handler
        (_("DWARF error: abstract instance recursion detected"));
      bfd_set_error (bfd_error_bad_value);
      return false;
    }

  /* DW_FORM_ref_addr can reference an entry in a different CU. It
     is an offset from the .debug_info section, not the current CU.  */
  if (attr_ptr->form == DW_FORM_ref_addr)
    {
      /* We only support DW_FORM_ref_addr within the same file, so
         any relocations should be resolved already.  Check this by
         testing for a zero die_ref;  There can't be a valid reference
         to the header of a .debug_info section.
         DW_FORM_ref_addr is an offset relative to .debug_info.
         Normally when using the GNU linker this is accomplished by
         emitting a symbolic reference to a label, because .debug_info
         sections are linked at zero.  When there are multiple section
         groups containing .debug_info, as there might be in a
         relocatable object file, it would be reasonable to assume that
         a symbolic reference to a label in any .debug_info section
         might be used.  Since we lay out multiple .debug_info
         sections at non-zero VMAs (see place_sections), and read
         them contiguously into dwarf_info_buffer, that means the
         reference is relative to dwarf_info_buffer.  */
      size_t total;

      info_ptr = unit->file->dwarf_info_buffer;
      info_ptr_end = info_ptr + unit->file->dwarf_info_size;
      total = info_ptr_end - info_ptr;
      if (!die_ref)
        return true;
      else if (die_ref >= total)
        {
          _bfd_error_handler
            (_("DWARF error: invalid abstract instance DIE ref"));
          bfd_set_error (bfd_error_bad_value);
          return false;
        }
      info_ptr += die_ref;
    }
  else if (attr_ptr->form == DW_FORM_GNU_ref_alt)
    {
      bool first_time = unit->stash->alt.dwarf_info_buffer == NULL;

      info_ptr = read_alt_indirect_ref (unit, die_ref);
      if (first_time)
        unit->stash->alt.info_ptr = unit->stash->alt.dwarf_info_buffer;
      if (info_ptr == NULL)
        {
          _bfd_error_handler
            (_("DWARF error: unable to read alt ref %" PRIu64),
             (uint64_t) die_ref);
          bfd_set_error (bfd_error_bad_value);
          return false;
        }
      info_ptr_end = (unit->stash->alt.dwarf_info_buffer
                      + unit->stash->alt.dwarf_info_size);
      if (unit->stash->alt.all_comp_units)
        unit = unit->stash->alt.all_comp_units;
    }

  if (attr_ptr->form == DW_FORM_ref_addr
      || attr_ptr->form == DW_FORM_GNU_ref_alt)
    {
      /* Now find the CU containing this pointer.  */
      if (info_ptr >= unit->info_ptr_unit && info_ptr < unit->end_ptr)
        info_ptr_end = unit->end_ptr;
      else
        {
          /* Check other CUs to see if they contain the abbrev.  */
          struct comp_unit *u;

          for (u = unit->prev_unit; u != NULL; u = u->prev_unit)
            if (info_ptr >= u->info_ptr_unit && info_ptr < u->end_ptr)
              break;

          if (u == NULL)
            for (u = unit->next_unit; u != NULL; u = u->next_unit)
              if (info_ptr >= u->info_ptr_unit && info_ptr < u->end_ptr)
                break;

          if (attr_ptr->form == DW_FORM_ref_addr)
            while (u == NULL)
              {
                u = stash_comp_unit (unit->stash, &unit->stash->f);
                if (u == NULL)
                  break;
                if (info_ptr >= u->info_ptr_unit && info_ptr < u->end_ptr)
                  break;
                u = NULL;
              }

          if (attr_ptr->form == DW_FORM_GNU_ref_alt)
            while (u == NULL)
              {
                u = stash_comp_unit (unit->stash, &unit->stash->alt);
                if (u == NULL)
                  break;
                if (info_ptr >= u->info_ptr_unit && info_ptr < u->end_ptr)
                  break;
                u = NULL;
              }

          if (u == NULL)
            {
              _bfd_error_handler
                (_("DWARF error: unable to locate abstract instance DIE ref %"
                   PRIu64), (uint64_t) die_ref);
              bfd_set_error (bfd_error_bad_value);
              return false;
            }
          unit = u;
          info_ptr_end = unit->end_ptr;
        }
    }
  else
    {
      /* DW_FORM_ref1, DW_FORM_ref2, DW_FORM_ref4, DW_FORM_ref8 or
         DW_FORM_ref_udata.  These are all references relative to the
         start of the current CU.  */
      size_t total;

      info_ptr = unit->info_ptr_unit;
      info_ptr_end = unit->end_ptr;
      total = info_ptr_end - info_ptr;
      if (!die_ref || die_ref >= total)
        {
          _bfd_error_handler
            (_("DWARF error: invalid abstract instance DIE ref"));
          bfd_set_error (bfd_error_bad_value);
          return false;
        }
      info_ptr += die_ref;
    }

  abbrev_number = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                         false, info_ptr_end);
  if (abbrev_number)
    {
      abbrev = lookup_abbrev (abbrev_number, unit->abbrevs);
      if (! abbrev)
        {
          _bfd_error_handler
            (_("DWARF error: could not find abbrev number %u"), abbrev_number);
          bfd_set_error (bfd_error_bad_value);
          return false;
        }
      else
        {
          for (i = 0; i < abbrev->num_attrs; ++i)
            {
              info_ptr = read_attribute (&attr, &abbrev->attrs[i], unit,
                                         info_ptr, info_ptr_end);
              if (info_ptr == NULL)
                break;
              switch (attr.name)
                {
                case DW_AT_name:
                  /* Prefer DW_AT_MIPS_linkage_name or DW_AT_linkage_name
                     over DW_AT_name.  */
                  if (name == NULL && is_str_attr (attr.form))
                    {
                      name = attr.u.str;
                      if (non_mangled (unit->lang))
                        *is_linkage = true;
                    }
                  break;
                case DW_AT_specification:
                  if (!find_abstract_instance (unit, &attr, recur_count + 1,
                                               &name, is_linkage,
                                               filename_ptr, linenumber_ptr))
                    return false;
                  break;
                case DW_AT_linkage_name:
                case DW_AT_MIPS_linkage_name:
                  /* PR 16949:  Corrupt debug info can place
                     non-string forms into these attributes.  */
                  if (is_str_attr (attr.form))
                    {
                      name = attr.u.str;
                      *is_linkage = true;
                    }
                  break;
                case DW_AT_decl_file:
                  if (!comp_unit_maybe_decode_line_info (unit))
                    return false;
                  *filename_ptr = concat_filename (unit->line_table,
                                                   attr.u.val);
                  break;
                case DW_AT_decl_line:
                  *linenumber_ptr = attr.u.val;
                  break;
                default:
                  break;
                }
            }
        }
    }
  *pname = name;
  return true;
}

static bool
read_ranges (struct comp_unit *unit, struct arange *arange,
             bfd_uint64_t offset)
{
  bfd_byte *ranges_ptr;
  bfd_byte *ranges_end;
  bfd_vma base_address = unit->base_address;

  if (! unit->file->dwarf_ranges_buffer)
    {
      if (! read_debug_ranges (unit))
        return false;
    }

  if (offset > unit->file->dwarf_ranges_size)
    return false;
  ranges_ptr = unit->file->dwarf_ranges_buffer + offset;
  ranges_end = unit->file->dwarf_ranges_buffer + unit->file->dwarf_ranges_size;

  for (;;)
    {
      bfd_vma low_pc;
      bfd_vma high_pc;

      /* PR 17512: file: 62cada7d.  */
      if (2u * unit->addr_size > (size_t) (ranges_end - ranges_ptr))
        return false;

      low_pc = read_address (unit, &ranges_ptr, ranges_end);
      high_pc = read_address (unit, &ranges_ptr, ranges_end);

      if (low_pc == 0 && high_pc == 0)
        break;
      if (low_pc == -1UL && high_pc != -1UL)
        base_address = high_pc;
      else
        {
          if (!arange_add (unit, arange,
                           base_address + low_pc, base_address + high_pc))
            return false;
        }
    }
  return true;
}

static bool
read_rnglists (struct comp_unit *unit, struct arange *arange,
               bfd_uint64_t offset)
{
  bfd_byte *rngs_ptr;
  bfd_byte *rngs_end;
  bfd_vma base_address = unit->base_address;
  bfd_vma low_pc;
  bfd_vma high_pc;
  bfd *abfd = unit->abfd;

  if (! unit->file->dwarf_rnglists_buffer)
    {
      if (! read_debug_rnglists (unit))
        return false;
    }

  rngs_ptr = unit->file->dwarf_rnglists_buffer + offset;
  if (rngs_ptr < unit->file->dwarf_rnglists_buffer)
    return false;
  rngs_end = unit->file->dwarf_rnglists_buffer;
  rngs_end +=  unit->file->dwarf_rnglists_size;

  for (;;)
    {
      enum dwarf_range_list_entry rlet;

      if (rngs_ptr >= rngs_end)
        return false;

      rlet = read_1_byte (abfd, &rngs_ptr, rngs_end);

      switch (rlet)
        {
        case DW_RLE_end_of_list:
          return true;

        case DW_RLE_base_address:
          if (unit->addr_size > (size_t) (rngs_end - rngs_ptr))
            return false;
          base_address = read_address (unit, &rngs_ptr, rngs_end);
          continue;

        case DW_RLE_start_length:
          if (unit->addr_size > (size_t) (rngs_end - rngs_ptr))
            return false;
          low_pc = read_address (unit, &rngs_ptr, rngs_end);
          high_pc = low_pc;
          high_pc += _bfd_safe_read_leb128 (abfd, &rngs_ptr,
                                            false, rngs_end);
          break;

        case DW_RLE_offset_pair:
          low_pc = base_address;
          low_pc += _bfd_safe_read_leb128 (abfd, &rngs_ptr,
                                           false, rngs_end);
          high_pc = base_address;
          high_pc += _bfd_safe_read_leb128 (abfd, &rngs_ptr,
                                            false, rngs_end);
          break;

        case DW_RLE_start_end:
          if (2u * unit->addr_size > (size_t) (rngs_end - rngs_ptr))
            return false;
          low_pc = read_address (unit, &rngs_ptr, rngs_end);
          high_pc = read_address (unit, &rngs_ptr, rngs_end);
          break;

        /* TODO x-variants need .debug_addr support used for split-dwarf.  */
        case DW_RLE_base_addressx:
        case DW_RLE_startx_endx:
        case DW_RLE_startx_length:
        default:
          return false;
        }

      if (!arange_add (unit, arange, low_pc, high_pc))
        return false;
    }
}

static bool
read_rangelist (struct comp_unit *unit, struct arange *arange,
                bfd_uint64_t offset)
{
  if (unit->version <= 4)
    return read_ranges (unit, arange, offset);
  else
    return read_rnglists (unit, arange, offset);
}

static struct funcinfo *
lookup_func_by_offset (bfd_uint64_t offset, struct funcinfo * table)
{
  for (; table != NULL; table = table->prev_func)
    if (table->unit_offset == offset)
      return table;
  return NULL;
}

static struct varinfo *
lookup_var_by_offset (bfd_uint64_t offset, struct varinfo * table)
{
  while (table)
    {
      if (table->unit_offset == offset)
        return table;
      table = table->prev_var;
    }

  return NULL;
}


/* DWARF2 Compilation unit functions.  */

/* Scan over each die in a comp. unit looking for functions to add
   to the function table and variables to the variable table.  */

static bool
scan_unit_for_symbols (struct comp_unit *unit)
{
  bfd *abfd = unit->abfd;
  bfd_byte *info_ptr = unit->first_child_die_ptr;
  bfd_byte *info_ptr_end = unit->end_ptr;
  int nesting_level = 0;
  struct nest_funcinfo
  {
    struct funcinfo *func;
  } *nested_funcs;
  int nested_funcs_size;

  /* Maintain a stack of in-scope functions and inlined functions, which we
     can use to set the caller_func field.  */
  nested_funcs_size = 32;
  nested_funcs = (struct nest_funcinfo *)
    bfd_malloc (nested_funcs_size * sizeof (*nested_funcs));
  if (nested_funcs == NULL)
    return false;
  nested_funcs[nesting_level].func = 0;

  /* PR 27484: We must scan the DIEs twice.  The first time we look for
     function and variable tags and accumulate them into their respective
     tables.  The second time through we process the attributes of the
     functions/variables and augment the table entries.  */
  while (nesting_level >= 0)
    {
      unsigned int abbrev_number, i;
      struct abbrev_info *abbrev;
      struct funcinfo *func;
      struct varinfo *var;
      bfd_uint64_t current_offset;

      /* PR 17512: file: 9f405d9d.  */
      if (info_ptr >= info_ptr_end)
        goto fail;

      current_offset = info_ptr - unit->info_ptr_unit;
      abbrev_number = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                             false, info_ptr_end);
      if (abbrev_number == 0)
        {
          nesting_level--;
          continue;
        }

      abbrev = lookup_abbrev (abbrev_number, unit->abbrevs);
      if (! abbrev)
        {
          static unsigned int previous_failed_abbrev = -1U;

          /* Avoid multiple reports of the same missing abbrev.  */
          if (abbrev_number != previous_failed_abbrev)
            {
              _bfd_error_handler
                (_("DWARF error: could not find abbrev number %u"),
                 abbrev_number);
              previous_failed_abbrev = abbrev_number;
            }
          bfd_set_error (bfd_error_bad_value);
          goto fail;
        }

      if (abbrev->tag == DW_TAG_subprogram
          || abbrev->tag == DW_TAG_entry_point
          || abbrev->tag == DW_TAG_inlined_subroutine)
        {
          size_t amt = sizeof (struct funcinfo);

          var = NULL;
          func = (struct funcinfo *) bfd_zalloc (abfd, amt);
          if (func == NULL)
            goto fail;
          func->tag = abbrev->tag;
          func->prev_func = unit->function_table;
          func->unit_offset = current_offset;
          unit->function_table = func;
          unit->number_of_functions++;
          BFD_ASSERT (!unit->cached);

          if (func->tag == DW_TAG_inlined_subroutine)
            for (i = nesting_level; i-- != 0; )
              if (nested_funcs[i].func)
                {
                  func->caller_func = nested_funcs[i].func;
                  break;
                }
          nested_funcs[nesting_level].func = func;
        }
      else
        {
          func = NULL;
          if (abbrev->tag == DW_TAG_variable
              || abbrev->tag == DW_TAG_member)
            {
              size_t amt = sizeof (struct varinfo);

              var = (struct varinfo *) bfd_zalloc (abfd, amt);
              if (var == NULL)
                goto fail;
              var->tag = abbrev->tag;
              var->stack = true;
              var->prev_var = unit->variable_table;
              unit->variable_table = var;
              var->unit_offset = current_offset;
              /* PR 18205: Missing debug information can cause this
                 var to be attached to an already cached unit.  */
            }
          else
            var = NULL;

          /* No inline function in scope at this nesting level.  */
          nested_funcs[nesting_level].func = 0;
        }

      for (i = 0; i < abbrev->num_attrs; ++i)
        {
          struct attribute attr;

          info_ptr = read_attribute (&attr, &abbrev->attrs[i],
                                     unit, info_ptr, info_ptr_end);
          if (info_ptr == NULL)
            goto fail;
        }

      if (abbrev->has_children)
        {
          nesting_level++;

          if (nesting_level >= nested_funcs_size)
            {
              struct nest_funcinfo *tmp;

              nested_funcs_size *= 2;
              tmp = (struct nest_funcinfo *)
                bfd_realloc (nested_funcs,
                             nested_funcs_size * sizeof (*nested_funcs));
              if (tmp == NULL)
                goto fail;
              nested_funcs = tmp;
            }
          nested_funcs[nesting_level].func = 0;
        }
    }

  /* This is the second pass over the abbrevs.  */      
  info_ptr = unit->first_child_die_ptr;
  nesting_level = 0;
  
  while (nesting_level >= 0)
    {
      unsigned int abbrev_number, i;
      struct abbrev_info *abbrev;
      struct attribute attr;
      struct funcinfo *func;
      struct varinfo *var;
      bfd_vma low_pc = 0;
      bfd_vma high_pc = 0;
      bool high_pc_relative = false;
      bfd_uint64_t current_offset;

      /* PR 17512: file: 9f405d9d.  */
      if (info_ptr >= info_ptr_end)
        goto fail;

      current_offset = info_ptr - unit->info_ptr_unit;
      abbrev_number = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                             false, info_ptr_end);
      if (! abbrev_number)
        {
          nesting_level--;
          continue;
        }

      abbrev = lookup_abbrev (abbrev_number, unit->abbrevs);
      /* This should have been handled above.  */
      BFD_ASSERT (abbrev != NULL);

      func = NULL;
      var = NULL;
      if (abbrev->tag == DW_TAG_subprogram
          || abbrev->tag == DW_TAG_entry_point
          || abbrev->tag == DW_TAG_inlined_subroutine)
        {
          func = lookup_func_by_offset (current_offset, unit->function_table);
          if (func == NULL)
            goto fail;
        }
      else if (abbrev->tag == DW_TAG_variable
               || abbrev->tag == DW_TAG_member)
        {
          var = lookup_var_by_offset (current_offset, unit->variable_table);
          if (var == NULL)
            goto fail;
        }

      for (i = 0; i < abbrev->num_attrs; ++i)
        {
          info_ptr = read_attribute (&attr, &abbrev->attrs[i],
                                     unit, info_ptr, info_ptr_end);
          if (info_ptr == NULL)
            goto fail;

          if (func)
            {
              switch (attr.name)
                {
                case DW_AT_call_file:
                  func->caller_file = concat_filename (unit->line_table,
                                                       attr.u.val);
                  break;

                case DW_AT_call_line:
                  func->caller_line = attr.u.val;
                  break;

                case DW_AT_abstract_origin:
                case DW_AT_specification:
                  if (!find_abstract_instance (unit, &attr, 0,
                                               &func->name,
                                               &func->is_linkage,
                                               &func->file,
                                               &func->line))
                    goto fail;
                  break;

                case DW_AT_name:
                  /* Prefer DW_AT_MIPS_linkage_name or DW_AT_linkage_name
                     over DW_AT_name.  */
                  if (func->name == NULL && is_str_attr (attr.form))
                    {
                      func->name = attr.u.str;
                      if (non_mangled (unit->lang))
                        func->is_linkage = true;
                    }
                  break;

                case DW_AT_linkage_name:
                case DW_AT_MIPS_linkage_name:
                  /* PR 16949:  Corrupt debug info can place
                     non-string forms into these attributes.  */
                  if (is_str_attr (attr.form))
                    {
                      func->name = attr.u.str;
                      func->is_linkage = true;
                    }
                  break;

                case DW_AT_low_pc:
                  low_pc = attr.u.val;
                  break;

                case DW_AT_high_pc:
                  high_pc = attr.u.val;
                  high_pc_relative = attr.form != DW_FORM_addr;
                  break;

                case DW_AT_ranges:
                  if (!read_rangelist (unit, &func->arange, attr.u.val))
                    goto fail;
                  break;

                case DW_AT_decl_file:
                  func->file = concat_filename (unit->line_table,
                                                attr.u.val);
                  break;

                case DW_AT_decl_line:
                  func->line = attr.u.val;
                  break;

                default:
                  break;
                }
            }
          else if (var)
            {
              switch (attr.name)
                {
                case DW_AT_specification:
                  if (attr.u.val)
                    {
                      struct varinfo * spec_var;

                      spec_var = lookup_var_by_offset (attr.u.val,
                                                       unit->variable_table);
                      if (spec_var == NULL)
                        {
                          _bfd_error_handler (_("DWARF error: could not find "
                                                "variable specification "
                                                "at offset 0x%lx"),
                                              (unsigned long) attr.u.val);
                          break;
                        }

                      if (var->name == NULL)
                        var->name = spec_var->name;
                      if (var->file == NULL && spec_var->file != NULL)
                        var->file = strdup (spec_var->file);
                      if (var->line == 0)
                        var->line = spec_var->line;
                      if (var->sec == NULL)
                        var->sec = spec_var->sec;
                    }
                  break;

                case DW_AT_name:
                  if (is_str_attr (attr.form))
                    var->name = attr.u.str;
                  break;

                case DW_AT_decl_file:
                  var->file = concat_filename (unit->line_table,
                                               attr.u.val);
                  break;

                case DW_AT_decl_line:
                  var->line = attr.u.val;
                  break;

                case DW_AT_external:
                  if (attr.u.val != 0)
                    var->stack = false;
                  break;

                case DW_AT_location:
                  switch (attr.form)
                    {
                    case DW_FORM_block:
                    case DW_FORM_block1:
                    case DW_FORM_block2:
                    case DW_FORM_block4:
                    case DW_FORM_exprloc:
                      if (attr.u.blk->data != NULL
                          && *attr.u.blk->data == DW_OP_addr)
                        {
                          var->stack = false;

                          /* Verify that DW_OP_addr is the only opcode in the
                             location, in which case the block size will be 1
                             plus the address size.  */
                          /* ??? For TLS variables, gcc can emit
                             DW_OP_addr <addr> DW_OP_GNU_push_tls_address
                             which we don't handle here yet.  */
                          if (attr.u.blk->size == unit->addr_size + 1U)
                            var->addr = bfd_get (unit->addr_size * 8,
                                                 unit->abfd,
                                                 attr.u.blk->data + 1);
                        }
                      break;

                    default:
                      break;
                    }
                  break;

                default:
                  break;
                }
            }
        }

      if (abbrev->has_children)
        nesting_level++;

      if (high_pc_relative)
        high_pc += low_pc;

      if (func && high_pc != 0)
        {
          if (!arange_add (unit, &func->arange, low_pc, high_pc))
            goto fail;
        }
    }

  free (nested_funcs);
  return true;

 fail:
  free (nested_funcs);
  return false;
}

/* Parse a DWARF2 compilation unit starting at INFO_PTR.  UNIT_LENGTH
   includes the compilation unit header that proceeds the DIE's, but
   does not include the length field that precedes each compilation
   unit header.  END_PTR points one past the end of this comp unit.
   OFFSET_SIZE is the size of DWARF2 offsets (either 4 or 8 bytes).

   This routine does not read the whole compilation unit; only enough
   to get to the line number information for the compilation unit.  */

static struct comp_unit *
parse_comp_unit (struct dwarf2_debug *stash,
                 struct dwarf2_debug_file *file,
                 bfd_byte *info_ptr,
                 bfd_vma unit_length,
                 bfd_byte *info_ptr_unit,
                 unsigned int offset_size)
{
  struct comp_unit* unit;
  unsigned int version;
  bfd_uint64_t abbrev_offset = 0;
  /* Initialize it just to avoid a GCC false warning.  */
  unsigned int addr_size = -1;
  struct abbrev_info** abbrevs;
  unsigned int abbrev_number, i;
  struct abbrev_info *abbrev;
  struct attribute attr;
  bfd_byte *end_ptr = info_ptr + unit_length;
  size_t amt;
  bfd_vma low_pc = 0;
  bfd_vma high_pc = 0;
  bfd *abfd = file->bfd_ptr;
  bool high_pc_relative = false;
  enum dwarf_unit_type unit_type;

  version = read_2_bytes (abfd, &info_ptr, end_ptr);
  if (version < 2 || version > 5)
    {
      /* PR 19872: A version number of 0 probably means that there is padding
         at the end of the .debug_info section.  Gold puts it there when
         performing an incremental link, for example.  So do not generate
         an error, just return a NULL.  */
      if (version)
        {
          _bfd_error_handler
            (_("DWARF error: found dwarf version '%u', this reader"
               " only handles version 2, 3, 4 and 5 information"), version);
          bfd_set_error (bfd_error_bad_value);
        }
      return NULL;
    }

  if (version < 5)
    unit_type = DW_UT_compile;
  else
    {
      unit_type = read_1_byte (abfd, &info_ptr, end_ptr);
      addr_size = read_1_byte (abfd, &info_ptr, end_ptr);
    }

  BFD_ASSERT (offset_size == 4 || offset_size == 8);
  if (offset_size == 4)
    abbrev_offset = read_4_bytes (abfd, &info_ptr, end_ptr);
  else
    abbrev_offset = read_8_bytes (abfd, &info_ptr, end_ptr);

  if (version < 5)
    addr_size = read_1_byte (abfd, &info_ptr, end_ptr);

  if (unit_type == DW_UT_type)
    {
      /* Skip type signature.  */
      info_ptr += 8;

      /* Skip type offset.  */
      info_ptr += offset_size;
    }

  if (addr_size > sizeof (bfd_vma))
    {
      _bfd_error_handler
        /* xgettext: c-format */
        (_("DWARF error: found address size '%u', this reader"
           " can not handle sizes greater than '%u'"),
         addr_size,
         (unsigned int) sizeof (bfd_vma));
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  if (addr_size != 2 && addr_size != 4 && addr_size != 8)
    {
      _bfd_error_handler
        ("DWARF error: found address size '%u', this reader"
         " can only handle address sizes '2', '4' and '8'", addr_size);
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  /* Read the abbrevs for this compilation unit into a table.  */
  abbrevs = read_abbrevs (abfd, abbrev_offset, stash, file);
  if (! abbrevs)
    return NULL;

  abbrev_number = _bfd_safe_read_leb128 (abfd, &info_ptr,
                                         false, end_ptr);
  if (! abbrev_number)
    {
      /* PR 19872: An abbrev number of 0 probably means that there is padding
         at the end of the .debug_abbrev section.  Gold puts it there when
         performing an incremental link, for example.  So do not generate
         an error, just return a NULL.  */
      return NULL;
    }

  abbrev = lookup_abbrev (abbrev_number, abbrevs);
  if (! abbrev)
    {
      _bfd_error_handler (_("DWARF error: could not find abbrev number %u"),
                          abbrev_number);
      bfd_set_error (bfd_error_bad_value);
      return NULL;
    }

  amt = sizeof (struct comp_unit);
  unit = (struct comp_unit *) bfd_zalloc (abfd, amt);
  if (unit == NULL)
    return NULL;
  unit->abfd = abfd;
  unit->version = version;
  unit->addr_size = addr_size;
  unit->offset_size = offset_size;
  unit->abbrevs = abbrevs;
  unit->end_ptr = end_ptr;
  unit->stash = stash;
  unit->file = file;
  unit->info_ptr_unit = info_ptr_unit;

  for (i = 0; i < abbrev->num_attrs; ++i)
    {
      info_ptr = read_attribute (&attr, &abbrev->attrs[i], unit, info_ptr, end_ptr);
      if (info_ptr == NULL)
        return NULL;

      /* Store the data if it is of an attribute we want to keep in a
         partial symbol table.  */
      switch (attr.name)
        {
        case DW_AT_stmt_list:
          unit->stmtlist = 1;
          unit->line_offset = attr.u.val;
          break;

        case DW_AT_name:
          if (is_str_attr (attr.form))
            unit->name = attr.u.str;
          break;

        case DW_AT_low_pc:
          low_pc = attr.u.val;
          /* If the compilation unit DIE has a DW_AT_low_pc attribute,
             this is the base address to use when reading location
             lists or range lists.  */
          if (abbrev->tag == DW_TAG_compile_unit)
            unit->base_address = low_pc;
          break;

        case DW_AT_high_pc:
          high_pc = attr.u.val;
          high_pc_relative = attr.form != DW_FORM_addr;
          break;

        case DW_AT_ranges:
          if (!read_rangelist (unit, &unit->arange, attr.u.val))
            return NULL;
          break;

        case DW_AT_comp_dir:
          {
            char *comp_dir = attr.u.str;

            /* PR 17512: file: 1fe726be.  */
            if (! is_str_attr (attr.form))
              {
                _bfd_error_handler
                  (_("DWARF error: DW_AT_comp_dir attribute encountered with a non-string form"));
                comp_dir = NULL;
              }

            if (comp_dir)
              {
                /* Irix 6.2 native cc prepends <machine>.: to the compilation
                   directory, get rid of it.  */
                char *cp = strchr (comp_dir, ':');

                if (cp && cp != comp_dir && cp[-1] == '.' && cp[1] == '/')
                  comp_dir = cp + 1;
              }
            unit->comp_dir = comp_dir;
            break;
          }

        case DW_AT_language:
          unit->lang = attr.u.val;
          break;

        default:
          break;
        }
    }
  if (high_pc_relative)
    high_pc += low_pc;
  if (high_pc != 0)
    {
      if (!arange_add (unit, &unit->arange, low_pc, high_pc))
        return NULL;
    }

  unit->first_child_die_ptr = info_ptr;
  return unit;
}

/* Return TRUE if UNIT may contain the address given by ADDR.  When
   there are functions written entirely with inline asm statements, the
   range info in the compilation unit header may not be correct.  We
   need to consult the line info table to see if a compilation unit
   really contains the given address.  */

static bool
comp_unit_contains_address (struct comp_unit *unit, bfd_vma addr)
{
  struct arange *arange;

  if (unit->error)
    return false;

  arange = &unit->arange;
  do
    {
      if (addr >= arange->low && addr < arange->high)
        return true;
      arange = arange->next;
    }
  while (arange);

  return false;
}

/* If UNIT contains ADDR, set the output parameters to the values for
   the line containing ADDR.  The output parameters, FILENAME_PTR,
   FUNCTION_PTR, and LINENUMBER_PTR, are pointers to the objects
   to be filled in.

   Returns the range of addresses covered by the entry that was used
   to fill in *LINENUMBER_PTR or 0 if it was not filled in.  */

static bfd_vma
comp_unit_find_nearest_line (struct comp_unit *unit,
                             bfd_vma addr,
                             const char **filename_ptr,
                             struct funcinfo **function_ptr,
                             unsigned int *linenumber_ptr,
                             unsigned int *discriminator_ptr)
{
  bool func_p;

  if (!comp_unit_maybe_decode_line_info (unit))
    return false;

  *function_ptr = NULL;
  func_p = lookup_address_in_function_table (unit, addr, function_ptr);
  if (func_p && (*function_ptr)->tag == DW_TAG_inlined_subroutine)
    unit->stash->inliner_chain = *function_ptr;

  return lookup_address_in_line_info_table (unit->line_table, addr,
                                            filename_ptr,
                                            linenumber_ptr,
                                            discriminator_ptr);
}

/* Check to see if line info is already decoded in a comp_unit.
   If not, decode it.  Returns TRUE if no errors were encountered;
   FALSE otherwise.  */

static bool
comp_unit_maybe_decode_line_info (struct comp_unit *unit)
{
  if (unit->error)
    return false;

  if (! unit->line_table)
    {
      if (! unit->stmtlist)
        {
          unit->error = 1;
          return false;
        }

      unit->line_table = decode_line_info (unit);

      if (! unit->line_table)
        {
          unit->error = 1;
          return false;
        }

      if (unit->first_child_die_ptr < unit->end_ptr
          && ! scan_unit_for_symbols (unit))
        {
          unit->error = 1;
          return false;
        }
    }

  return true;
}

/* If UNIT contains SYM at ADDR, set the output parameters to the
   values for the line containing SYM.  The output parameters,
   FILENAME_PTR, and LINENUMBER_PTR, are pointers to the objects to be
   filled in.

   Return TRUE if UNIT contains SYM, and no errors were encountered;
   FALSE otherwise.  */

static bool
comp_unit_find_line (struct comp_unit *unit,
                     asymbol *sym,
                     bfd_vma addr,
                     const char **filename_ptr,
                     unsigned int *linenumber_ptr)
{
  if (!comp_unit_maybe_decode_line_info (unit))
    return false;

  if (sym->flags & BSF_FUNCTION)
    return lookup_symbol_in_function_table (unit, sym, addr,
                                            filename_ptr,
                                            linenumber_ptr);

  return lookup_symbol_in_variable_table (unit, sym, addr,
                                          filename_ptr,
                                          linenumber_ptr);
}

static struct funcinfo *
reverse_funcinfo_list (struct funcinfo *head)
{
  struct funcinfo *rhead;
  struct funcinfo *temp;

  for (rhead = NULL; head; head = temp)
    {
      temp = head->prev_func;
      head->prev_func = rhead;
      rhead = head;
    }
  return rhead;
}

static struct varinfo *
reverse_varinfo_list (struct varinfo *head)
{
  struct varinfo *rhead;
  struct varinfo *temp;

  for (rhead = NULL; head; head = temp)
    {
      temp = head->prev_var;
      head->prev_var = rhead;
      rhead = head;
    }
  return rhead;
}

/* Extract all interesting funcinfos and varinfos of a compilation
   unit into hash tables for faster lookup.  Returns TRUE if no
   errors were enountered; FALSE otherwise.  */

static bool
comp_unit_hash_info (struct dwarf2_debug *stash,
                     struct comp_unit *unit,
                     struct info_hash_table *funcinfo_hash_table,
                     struct info_hash_table *varinfo_hash_table)
{
  struct funcinfo* each_func;
  struct varinfo* each_var;
  bool okay = true;

  BFD_ASSERT (stash->info_hash_status != STASH_INFO_HASH_DISABLED);

  if (!comp_unit_maybe_decode_line_info (unit))
    return false;

  BFD_ASSERT (!unit->cached);

  /* To preserve the original search order, we went to visit the function
     infos in the reversed order of the list.  However, making the list
     bi-directional use quite a bit of extra memory.  So we reverse
     the list first, traverse the list in the now reversed order and
     finally reverse the list again to get back the original order.  */
  unit->function_table = reverse_funcinfo_list (unit->function_table);
  for (each_func = unit->function_table;
       each_func && okay;
       each_func = each_func->prev_func)
    {
      /* Skip nameless functions.  */
      if (each_func->name)
        /* There is no need to copy name string into hash table as
           name string is either in the dwarf string buffer or
           info in the stash.  */
        okay = insert_info_hash_table (funcinfo_hash_table, each_func->name,
                                       (void*) each_func, false);
    }
  unit->function_table = reverse_funcinfo_list (unit->function_table);
  if (!okay)
    return false;

  /* We do the same for variable infos.  */
  unit->variable_table = reverse_varinfo_list (unit->variable_table);
  for (each_var = unit->variable_table;
       each_var && okay;
       each_var = each_var->prev_var)
    {
      /* Skip stack vars and vars with no files or names.  */
      if (! each_var->stack
          && each_var->file != NULL
          && each_var->name != NULL)
        /* There is no need to copy name string into hash table as
           name string is either in the dwarf string buffer or
           info in the stash.  */
        okay = insert_info_hash_table (varinfo_hash_table, each_var->name,
                                       (void*) each_var, false);
    }

  unit->variable_table = reverse_varinfo_list (unit->variable_table);
  unit->cached = true;
  return okay;
}

/* Locate a section in a BFD containing debugging info.  The search starts
   from the section after AFTER_SEC, or from the first section in the BFD if
   AFTER_SEC is NULL.  The search works by examining the names of the
   sections.  There are three permissiable names.  The first two are given
   by DEBUG_SECTIONS[debug_info] (whose standard DWARF2 names are .debug_info
   and .zdebug_info).  The third is a prefix .gnu.linkonce.wi.
   This is a variation on the .debug_info section which has a checksum
   describing the contents appended onto the name.  This allows the linker to
   identify and discard duplicate debugging sections for different
   compilation units.  */
#define GNU_LINKONCE_INFO ".gnu.linkonce.wi."

static asection *
find_debug_info (bfd *abfd, const struct dwarf_debug_section *debug_sections,
                 asection *after_sec)
{
  asection *msec;
  const char *look;

  if (after_sec == NULL)
    {
      look = debug_sections[debug_info].uncompressed_name;
      msec = bfd_get_section_by_name (abfd, look);
      if (msec != NULL)
        return msec;

      look = debug_sections[debug_info].compressed_name;
      msec = bfd_get_section_by_name (abfd, look);
      if (msec != NULL)
        return msec;

      for (msec = abfd->sections; msec != NULL; msec = msec->next)
        if (startswith (msec->name, GNU_LINKONCE_INFO))
          return msec;

      return NULL;
    }

  for (msec = after_sec->next; msec != NULL; msec = msec->next)
    {
      look = debug_sections[debug_info].uncompressed_name;
      if (strcmp (msec->name, look) == 0)
        return msec;

      look = debug_sections[debug_info].compressed_name;
      if (look != NULL && strcmp (msec->name, look) == 0)
        return msec;

      if (startswith (msec->name, GNU_LINKONCE_INFO))
        return msec;
    }

  return NULL;
}

/* Transfer VMAs from object file to separate debug file.  */

static void
set_debug_vma (bfd *orig_bfd, bfd *debug_bfd)
{
  asection *s, *d;

  for (s = orig_bfd->sections, d = debug_bfd->sections;
       s != NULL && d != NULL;
       s = s->next, d = d->next)
    {
      if ((d->flags & SEC_DEBUGGING) != 0)
        break;
      /* ??? Assumes 1-1 correspondence between sections in the
         two files.  */
      if (strcmp (s->name, d->name) == 0)
        {
          d->output_section = s->output_section;
          d->output_offset = s->output_offset;
          d->vma = s->vma;
        }
    }
}

/* If the dwarf2 info was found in a separate debug file, return the
   debug file section corresponding to the section in the original file
   and the debug file symbols.  */

static void
_bfd_dwarf2_stash_syms (struct dwarf2_debug *stash, bfd *abfd,
                        asection **sec, asymbol ***syms)
{
  if (stash->f.bfd_ptr != abfd)
    {
      asection *s, *d;

      if (*sec == NULL)
        {
          *syms = stash->f.syms;
          return;
        }

      for (s = abfd->sections, d = stash->f.bfd_ptr->sections;
           s != NULL && d != NULL;
           s = s->next, d = d->next)
        {
          if ((d->flags & SEC_DEBUGGING) != 0)
            break;
          if (s == *sec
              && strcmp (s->name, d->name) == 0)
            {
              *sec = d;
              *syms = stash->f.syms;
              break;
            }
        }
    }
}

/* Unset vmas for adjusted sections in STASH.  */

static void
unset_sections (struct dwarf2_debug *stash)
{
  int i;
  struct adjusted_section *p;

  i = stash->adjusted_section_count;
  p = stash->adjusted_sections;
  for (; i > 0; i--, p++)
    p->section->vma = 0;
}

/* Set VMAs for allocated and .debug_info sections in ORIG_BFD, a
   relocatable object file.  VMAs are normally all zero in relocatable
   object files, so if we want to distinguish locations in sections by
   address we need to set VMAs so the sections do not overlap.  We
   also set VMA on .debug_info so that when we have multiple
   .debug_info sections (or the linkonce variant) they also do not
   overlap.  The multiple .debug_info sections make up a single
   logical section.  ??? We should probably do the same for other
   debug sections.  */

static bool
place_sections (bfd *orig_bfd, struct dwarf2_debug *stash)
{
  bfd *abfd;
  struct adjusted_section *p;
  int i;
  const char *debug_info_name;

  if (stash->adjusted_section_count != 0)
    {
      i = stash->adjusted_section_count;
      p = stash->adjusted_sections;
      for (; i > 0; i--, p++)
        p->section->vma = p->adj_vma;
      return true;
    }

  debug_info_name = stash->debug_sections[debug_info].uncompressed_name;
  i = 0;
  abfd = orig_bfd;
  while (1)
    {
      asection *sect;

      for (sect = abfd->sections; sect != NULL; sect = sect->next)
        {
          int is_debug_info;

          if ((sect->output_section != NULL
               && sect->output_section != sect
               && (sect->flags & SEC_DEBUGGING) == 0)
              || sect->vma != 0)
            continue;

          is_debug_info = (strcmp (sect->name, debug_info_name) == 0
                           || startswith (sect->name, GNU_LINKONCE_INFO));

          if (!((sect->flags & SEC_ALLOC) != 0 && abfd == orig_bfd)
              && !is_debug_info)
            continue;

          i++;
        }
      if (abfd == stash->f.bfd_ptr)
        break;
      abfd = stash->f.bfd_ptr;
    }

  if (i <= 1)
    stash->adjusted_section_count = -1;
  else
    {
      bfd_vma last_vma = 0, last_dwarf = 0;
      size_t amt = i * sizeof (struct adjusted_section);

      p = (struct adjusted_section *) bfd_malloc (amt);
      if (p == NULL)
        return false;

      stash->adjusted_sections = p;
      stash->adjusted_section_count = i;

      abfd = orig_bfd;
      while (1)
        {
          asection *sect;

          for (sect = abfd->sections; sect != NULL; sect = sect->next)
            {
              bfd_size_type sz;
              int is_debug_info;

              if ((sect->output_section != NULL
                   && sect->output_section != sect
                   && (sect->flags & SEC_DEBUGGING) == 0)
                  || sect->vma != 0)
                continue;

              is_debug_info = (strcmp (sect->name, debug_info_name) == 0
                               || startswith (sect->name, GNU_LINKONCE_INFO));

              if (!((sect->flags & SEC_ALLOC) != 0 && abfd == orig_bfd)
                  && !is_debug_info)
                continue;

              sz = sect->rawsize ? sect->rawsize : sect->size;

              if (is_debug_info)
                {
                  BFD_ASSERT (sect->alignment_power == 0);
                  sect->vma = last_dwarf;
                  last_dwarf += sz;
                }
              else
                {
                  /* Align the new address to the current section
                     alignment.  */
                  last_vma = ((last_vma
                               + ~(-((bfd_vma) 1 << sect->alignment_power)))
                              & (-((bfd_vma) 1 << sect->alignment_power)));
                  sect->vma = last_vma;
                  last_vma += sz;
                }

              p->section = sect;
              p->adj_vma = sect->vma;
              p++;
            }
          if (abfd == stash->f.bfd_ptr)
            break;
          abfd = stash->f.bfd_ptr;
        }
    }

  if (orig_bfd != stash->f.bfd_ptr)
    set_debug_vma (orig_bfd, stash->f.bfd_ptr);

  return true;
}

/* Look up a funcinfo by name using the given info hash table.  If found,
   also update the locations pointed to by filename_ptr and linenumber_ptr.

   This function returns TRUE if a funcinfo that matches the given symbol
   and address is found with any error; otherwise it returns FALSE.  */

static bool
info_hash_lookup_funcinfo (struct info_hash_table *hash_table,
                           asymbol *sym,
                           bfd_vma addr,
                           const char **filename_ptr,
                           unsigned int *linenumber_ptr)
{
  struct funcinfo* each_func;
  struct funcinfo* best_fit = NULL;
  bfd_vma best_fit_len = 0;
  struct info_list_node *node;
  struct arange *arange;
  const char *name = bfd_asymbol_name (sym);
  asection *sec = bfd_asymbol_section (sym);

  for (node = lookup_info_hash_table (hash_table, name);
       node;
       node = node->next)
    {
      each_func = (struct funcinfo *) node->info;
      for (arange = &each_func->arange;
           arange;
           arange = arange->next)
        {
          if ((!each_func->sec || each_func->sec == sec)
              && addr >= arange->low
              && addr < arange->high
              && (!best_fit
                  || arange->high - arange->low < best_fit_len))
            {
              best_fit = each_func;
              best_fit_len = arange->high - arange->low;
            }
        }
    }

  if (best_fit)
    {
      best_fit->sec = sec;
      *filename_ptr = best_fit->file;
      *linenumber_ptr = best_fit->line;
      return true;
    }

  return false;
}

/* Look up a varinfo by name using the given info hash table.  If found,
   also update the locations pointed to by filename_ptr and linenumber_ptr.

   This function returns TRUE if a varinfo that matches the given symbol
   and address is found with any error; otherwise it returns FALSE.  */

static bool
info_hash_lookup_varinfo (struct info_hash_table *hash_table,
                          asymbol *sym,
                          bfd_vma addr,
                          const char **filename_ptr,
                          unsigned int *linenumber_ptr)
{
  const char *name = bfd_asymbol_name (sym);
  asection *sec = bfd_asymbol_section (sym);
  struct varinfo* each;
  struct info_list_node *node;

  for (node = lookup_info_hash_table (hash_table, name);
       node;
       node = node->next)
    {
      each = (struct varinfo *) node->info;
      if (each->addr == addr
          && (!each->sec || each->sec == sec))
        {
          each->sec = sec;
          *filename_ptr = each->file;
          *linenumber_ptr = each->line;
          return true;
        }
    }

  return false;
}

/* Update the funcinfo and varinfo info hash tables if they are
   not up to date.  Returns TRUE if there is no error; otherwise
   returns FALSE and disable the info hash tables.  */

static bool
stash_maybe_update_info_hash_tables (struct dwarf2_debug *stash)
{
  struct comp_unit *each;

  /* Exit if hash tables are up-to-date.  */
  if (stash->f.all_comp_units == stash->hash_units_head)
    return true;

  if (stash->hash_units_head)
    each = stash->hash_units_head->prev_unit;
  else
    each = stash->f.last_comp_unit;

  while (each)
    {
      if (!comp_unit_hash_info (stash, each, stash->funcinfo_hash_table,
                                stash->varinfo_hash_table))
        {
          stash->info_hash_status = STASH_INFO_HASH_DISABLED;
          return false;
        }
      each = each->prev_unit;
    }

  stash->hash_units_head = stash->f.all_comp_units;
  return true;
}

/* Check consistency of info hash tables.  This is for debugging only.  */

static void ATTRIBUTE_UNUSED
stash_verify_info_hash_table (struct dwarf2_debug *stash)
{
  struct comp_unit *each_unit;
  struct funcinfo *each_func;
  struct varinfo *each_var;
  struct info_list_node *node;
  bool found;

  for (each_unit = stash->f.all_comp_units;
       each_unit;
       each_unit = each_unit->next_unit)
    {
      for (each_func = each_unit->function_table;
           each_func;
           each_func = each_func->prev_func)
        {
          if (!each_func->name)
            continue;
          node = lookup_info_hash_table (stash->funcinfo_hash_table,
                                         each_func->name);
          BFD_ASSERT (node);
          found = false;
          while (node && !found)
            {
              found = node->info == each_func;
              node = node->next;
            }
          BFD_ASSERT (found);
        }

      for (each_var = each_unit->variable_table;
           each_var;
           each_var = each_var->prev_var)
        {
          if (!each_var->name || !each_var->file || each_var->stack)
            continue;
          node = lookup_info_hash_table (stash->varinfo_hash_table,
                                         each_var->name);
          BFD_ASSERT (node);
          found = false;
          while (node && !found)
            {
              found = node->info == each_var;
              node = node->next;
            }
          BFD_ASSERT (found);
        }
    }
}

/* Check to see if we want to enable the info hash tables, which consume
   quite a bit of memory.  Currently we only check the number times
   bfd_dwarf2_find_line is called.  In the future, we may also want to
   take the number of symbols into account.  */

static void
stash_maybe_enable_info_hash_tables (bfd *abfd, struct dwarf2_debug *stash)
{
  BFD_ASSERT (stash->info_hash_status == STASH_INFO_HASH_OFF);

  if (stash->info_hash_count++ < STASH_INFO_HASH_TRIGGER)
    return;

  /* FIXME: Maybe we should check the reduce_memory_overheads
     and optimize fields in the bfd_link_info structure ?  */

  /* Create hash tables.  */
  stash->funcinfo_hash_table = create_info_hash_table (abfd);
  stash->varinfo_hash_table = create_info_hash_table (abfd);
  if (!stash->funcinfo_hash_table || !stash->varinfo_hash_table)
    {
      /* Turn off info hashes if any allocation above fails.  */
      stash->info_hash_status = STASH_INFO_HASH_DISABLED;
      return;
    }
  /* We need a forced update so that the info hash tables will
     be created even though there is no compilation unit.  That
     happens if STASH_INFO_HASH_TRIGGER is 0.  */
  if (stash_maybe_update_info_hash_tables (stash))
    stash->info_hash_status = STASH_INFO_HASH_ON;
}

/* Find the file and line associated with a symbol and address using the
   info hash tables of a stash. If there is a match, the function returns
   TRUE and update the locations pointed to by filename_ptr and linenumber_ptr;
   otherwise it returns FALSE.  */

static bool
stash_find_line_fast (struct dwarf2_debug *stash,
                      asymbol *sym,
                      bfd_vma addr,
                      const char **filename_ptr,
                      unsigned int *linenumber_ptr)
{
  BFD_ASSERT (stash->info_hash_status == STASH_INFO_HASH_ON);

  if (sym->flags & BSF_FUNCTION)
    return info_hash_lookup_funcinfo (stash->funcinfo_hash_table, sym, addr,
                                      filename_ptr, linenumber_ptr);
  return info_hash_lookup_varinfo (stash->varinfo_hash_table, sym, addr,
                                   filename_ptr, linenumber_ptr);
}

/* Save current section VMAs.  */

static bool
save_section_vma (const bfd *abfd, struct dwarf2_debug *stash)
{
  asection *s;
  unsigned int i;

  if (abfd->section_count == 0)
    return true;
  stash->sec_vma = bfd_malloc (sizeof (*stash->sec_vma) * abfd->section_count);
  if (stash->sec_vma == NULL)
    return false;
  stash->sec_vma_count = abfd->section_count;
  for (i = 0, s = abfd->sections;
       s != NULL && i < abfd->section_count;
       i++, s = s->next)
    {
      if (s->output_section != NULL)
        stash->sec_vma[i] = s->output_section->vma + s->output_offset;
      else
        stash->sec_vma[i] = s->vma;
    }
  return true;
}

/* Compare current section VMAs against those at the time the stash
   was created.  If find_nearest_line is used in linker warnings or
   errors early in the link process, the debug info stash will be
   invalid for later calls.  This is because we relocate debug info
   sections, so the stashed section contents depend on symbol values,
   which in turn depend on section VMAs.  */

static bool
section_vma_same (const bfd *abfd, const struct dwarf2_debug *stash)
{
  asection *s;
  unsigned int i;

  /* PR 24334: If the number of sections in ABFD has changed between
     when the stash was created and now, then we cannot trust the
     stashed vma information.  */
  if (abfd->section_count != stash->sec_vma_count)
    return false;

  for (i = 0, s = abfd->sections;
       s != NULL && i < abfd->section_count;
       i++, s = s->next)
    {
      bfd_vma vma;

      if (s->output_section != NULL)
        vma = s->output_section->vma + s->output_offset;
      else
        vma = s->vma;
      if (vma != stash->sec_vma[i])
        return false;
    }
  return true;
}

/* Read debug information from DEBUG_BFD when DEBUG_BFD is specified.
   If DEBUG_BFD is not specified, we read debug information from ABFD
   or its gnu_debuglink. The results will be stored in PINFO.
   The function returns TRUE iff debug information is ready.  */

bool
_bfd_dwarf2_slurp_debug_info (bfd *abfd, bfd *debug_bfd,
                              const struct dwarf_debug_section *debug_sections,
                              asymbol **symbols,
                              void **pinfo,
                              bool do_place)
{
  size_t amt = sizeof (struct dwarf2_debug);
  bfd_size_type total_size;
  asection *msec;
  struct dwarf2_debug *stash = (struct dwarf2_debug *) *pinfo;

  if (stash != NULL)
    {
      if (stash->orig_bfd == abfd
          && section_vma_same (abfd, stash))
        {
          /* Check that we did previously find some debug information
             before attempting to make use of it.  */
          if (stash->f.bfd_ptr != NULL)
            {
              if (do_place && !place_sections (abfd, stash))
                return false;
              return true;
            }

          return false;
        }
      _bfd_dwarf2_cleanup_debug_info (abfd, pinfo);
      memset (stash, 0, amt);
    }
  else
    {
      stash = (struct dwarf2_debug *) bfd_zalloc (abfd, amt);
      if (! stash)
        return false;
    }
  stash->orig_bfd = abfd;
  stash->debug_sections = debug_sections;
  stash->f.syms = symbols;
  if (!save_section_vma (abfd, stash))
    return false;

  stash->f.abbrev_offsets = htab_create_alloc (10, hash_abbrev, eq_abbrev,
                                               del_abbrev, calloc, free);
  if (!stash->f.abbrev_offsets)
    return false;

  stash->alt.abbrev_offsets = htab_create_alloc (10, hash_abbrev, eq_abbrev,
                                                 del_abbrev, calloc, free);
  if (!stash->alt.abbrev_offsets)
    return false;

  *pinfo = stash;

  if (debug_bfd == NULL)
    debug_bfd = abfd;

  msec = find_debug_info (debug_bfd, debug_sections, NULL);
  if (msec == NULL && abfd == debug_bfd)
    {
      char * debug_filename;

      debug_filename = bfd_follow_build_id_debuglink (abfd, DEBUGDIR);
      if (debug_filename == NULL)
        debug_filename = bfd_follow_gnu_debuglink (abfd, DEBUGDIR);

      if (debug_filename == NULL)
        /* No dwarf2 info, and no gnu_debuglink to follow.
           Note that at this point the stash has been allocated, but
           contains zeros.  This lets future calls to this function
           fail more quickly.  */
        return false;

      debug_bfd = bfd_openr (debug_filename, NULL);
      free (debug_filename);
      if (debug_bfd == NULL)
        /* FIXME: Should we report our failure to follow the debuglink ?  */
        return false;

      /* Set BFD_DECOMPRESS to decompress debug sections.  */
      debug_bfd->flags |= BFD_DECOMPRESS;
      if (!bfd_check_format (debug_bfd, bfd_object)
          || (msec = find_debug_info (debug_bfd,
                                      debug_sections, NULL)) == NULL
          || !bfd_generic_link_read_symbols (debug_bfd))
        {
          bfd_close (debug_bfd);
          return false;
        }

      symbols = bfd_get_outsymbols (debug_bfd);
      stash->f.syms = symbols;
      stash->close_on_cleanup = true;
    }
  stash->f.bfd_ptr = debug_bfd;

  if (do_place
      && !place_sections (abfd, stash))
    return false;

  /* There can be more than one DWARF2 info section in a BFD these
     days.  First handle the easy case when there's only one.  If
     there's more than one, try case two: none of the sections is
     compressed.  In that case, read them all in and produce one
     large stash.  We do this in two passes - in the first pass we
     just accumulate the section sizes, and in the second pass we
     read in the section's contents.  (The allows us to avoid
     reallocing the data as we add sections to the stash.)  If
     some or all sections are compressed, then do things the slow
     way, with a bunch of reallocs.  */

  if (! find_debug_info (debug_bfd, debug_sections, msec))
    {
      /* Case 1: only one info section.  */
      total_size = msec->size;
      if (! read_section (debug_bfd, &stash->debug_sections[debug_info],
                          symbols, 0,
                          &stash->f.dwarf_info_buffer, &total_size))
        return false;
    }
  else
    {
      /* Case 2: multiple sections.  */
      for (total_size = 0;
           msec;
           msec = find_debug_info (debug_bfd, debug_sections, msec))
        {
          /* Catch PR25070 testcase overflowing size calculation here.  */
          if (total_size + msec->size < total_size
              || total_size + msec->size < msec->size)
            {
              bfd_set_error (bfd_error_no_memory);
              return false;
            }
          total_size += msec->size;
        }

      stash->f.dwarf_info_buffer = (bfd_byte *) bfd_malloc (total_size);
      if (stash->f.dwarf_info_buffer == NULL)
        return false;

      total_size = 0;
      for (msec = find_debug_info (debug_bfd, debug_sections, NULL);
           msec;
           msec = find_debug_info (debug_bfd, debug_sections, msec))
        {
          bfd_size_type size;

          size = msec->size;
          if (size == 0)
            continue;

          if (!(bfd_simple_get_relocated_section_contents
                (debug_bfd, msec, stash->f.dwarf_info_buffer + total_size,
                 symbols)))
            return false;

          total_size += size;
        }
    }

  stash->f.info_ptr = stash->f.dwarf_info_buffer;
  stash->f.dwarf_info_size = total_size;
  return true;
}

/* Parse the next DWARF2 compilation unit at FILE->INFO_PTR.  */

static struct comp_unit *
stash_comp_unit (struct dwarf2_debug *stash, struct dwarf2_debug_file *file)
{
  bfd_size_type length;
  unsigned int offset_size;
  bfd_byte *info_ptr_unit = file->info_ptr;
  bfd_byte *info_ptr_end = file->dwarf_info_buffer + file->dwarf_info_size;

  if (file->info_ptr >= info_ptr_end)
    return NULL;

  length = read_4_bytes (file->bfd_ptr, &file->info_ptr, info_ptr_end);
  /* A 0xffffff length is the DWARF3 way of indicating
     we use 64-bit offsets, instead of 32-bit offsets.  */
  if (length == 0xffffffff)
    {
      offset_size = 8;
      length = read_8_bytes (file->bfd_ptr, &file->info_ptr, info_ptr_end);
    }
  /* A zero length is the IRIX way of indicating 64-bit offsets,
     mostly because the 64-bit length will generally fit in 32
     bits, and the endianness helps.  */
  else if (length == 0)
    {
      offset_size = 8;
      length = read_4_bytes (file->bfd_ptr, &file->info_ptr, info_ptr_end);
    }
  /* In the absence of the hints above, we assume 32-bit DWARF2
     offsets even for targets with 64-bit addresses, because:
     a) most of the time these targets will not have generated
     more than 2Gb of debug info and so will not need 64-bit
     offsets,
     and
     b) if they do use 64-bit offsets but they are not using
     the size hints that are tested for above then they are
     not conforming to the DWARF3 standard anyway.  */
  else
    offset_size = 4;

  if (length != 0
      && length <= (size_t) (info_ptr_end - file->info_ptr))
    {
      struct comp_unit *each = parse_comp_unit (stash, file,
                                                file->info_ptr, length,
                                                info_ptr_unit, offset_size);
      if (each)
        {
          if (file->all_comp_units)
            file->all_comp_units->prev_unit = each;
          else
            file->last_comp_unit = each;

          each->next_unit = file->all_comp_units;
          file->all_comp_units = each;

          file->info_ptr += length;
          return each;
        }
    }

  /* Don't trust any of the DWARF info after a corrupted length or
     parse error.  */
  file->info_ptr = info_ptr_end;
  return NULL;
}

/* Hash function for an asymbol.  */

static hashval_t
hash_asymbol (const void *sym)
{
  const asymbol *asym = sym;
  return htab_hash_string (asym->name);
}

/* Equality function for asymbols.  */

static int
eq_asymbol (const void *a, const void *b)
{
  const asymbol *sa = a;
  const asymbol *sb = b;
  return strcmp (sa->name, sb->name) == 0;
}

/* Scan the debug information in PINFO looking for a DW_TAG_subprogram
   abbrev with a DW_AT_low_pc attached to it.  Then lookup that same
   symbol in SYMBOLS and return the difference between the low_pc and
   the symbol's address.  Returns 0 if no suitable symbol could be found.  */

bfd_signed_vma
_bfd_dwarf2_find_symbol_bias (asymbol ** symbols, void ** pinfo)
{
  struct dwarf2_debug *stash;
  struct comp_unit * unit;
  htab_t sym_hash;
  bfd_signed_vma result = 0;
  asymbol ** psym;

  stash = (struct dwarf2_debug *) *pinfo;

  if (stash == NULL || symbols == NULL)
    return 0;

  sym_hash = htab_create_alloc (10, hash_asymbol, eq_asymbol,
                                NULL, xcalloc, free);
  for (psym = symbols; * psym != NULL; psym++)
    {
      asymbol * sym = * psym;

      if (sym->flags & BSF_FUNCTION && sym->section != NULL)
        {
          void **slot = htab_find_slot (sym_hash, sym, INSERT);
          *slot = sym;
        }
    }

  for (unit = stash->f.all_comp_units; unit; unit = unit->next_unit)
    {
      struct funcinfo * func;

      comp_unit_maybe_decode_line_info (unit);

      for (func = unit->function_table; func != NULL; func = func->prev_func)
        if (func->name && func->arange.low)
          {
            asymbol search, *sym;

            /* FIXME: Do we need to scan the aranges looking for the lowest pc value ?  */

            search.name = func->name;
            sym = htab_find (sym_hash, &search);
            if (sym != NULL)
              {
                result = ((bfd_signed_vma) func->arange.low) -
                  ((bfd_signed_vma) (sym->value + sym->section->vma));
                goto done;
              }
          }
    }

 done:
  htab_delete (sym_hash);
  return result;
}

/* Find the source code location of SYMBOL.  If SYMBOL is NULL
   then find the nearest source code location corresponding to
   the address SECTION + OFFSET.
   Returns 1 if the line is found without error and fills in
   FILENAME_PTR and LINENUMBER_PTR.  In the case where SYMBOL was
   NULL the FUNCTIONNAME_PTR is also filled in.
   Returns 2 if partial information from _bfd_elf_find_function is
   returned (function and maybe file) by looking at symbols.  DWARF2
   info is present but not regarding the requested code location.
   Returns 0 otherwise.
   SYMBOLS contains the symbol table for ABFD.
   DEBUG_SECTIONS contains the name of the dwarf debug sections.  */

int
_bfd_dwarf2_find_nearest_line (bfd *abfd,
                               asymbol **symbols,
                               asymbol *symbol,
                               asection *section,
                               bfd_vma offset,
                               const char **filename_ptr,
                               const char **functionname_ptr,
                               unsigned int *linenumber_ptr,
                               unsigned int *discriminator_ptr,
                               const struct dwarf_debug_section *debug_sections,
                               void **pinfo)
{
  /* Read each compilation unit from the section .debug_info, and check
     to see if it contains the address we are searching for.  If yes,
     lookup the address, and return the line number info.  If no, go
     on to the next compilation unit.

     We keep a list of all the previously read compilation units, and
     a pointer to the next un-read compilation unit.  Check the
     previously read units before reading more.  */
  struct dwarf2_debug *stash;
  /* What address are we looking for?  */
  bfd_vma addr;
  struct comp_unit* each;
  struct funcinfo *function = NULL;
  int found = false;
  bool do_line;

  *filename_ptr = NULL;
  if (functionname_ptr != NULL)
    *functionname_ptr = NULL;
  *linenumber_ptr = 0;
  if (discriminator_ptr)
    *discriminator_ptr = 0;

  if (! _bfd_dwarf2_slurp_debug_info (abfd, NULL, debug_sections,
                                      symbols, pinfo,
                                      (abfd->flags & (EXEC_P | DYNAMIC)) == 0))
    return false;

  stash = (struct dwarf2_debug *) *pinfo;

  do_line = symbol != NULL;
  if (do_line)
    {
      BFD_ASSERT (section == NULL && offset == 0 && functionname_ptr == NULL);
      section = bfd_asymbol_section (symbol);
      addr = symbol->value;
    }
  else
    {
      BFD_ASSERT (section != NULL && functionname_ptr != NULL);
      addr = offset;

      /* If we have no SYMBOL but the section we're looking at is not a
         code section, then take a look through the list of symbols to see
         if we have a symbol at the address we're looking for.  If we do
         then use this to look up line information.  This will allow us to
         give file and line results for data symbols.  We exclude code
         symbols here, if we look up a function symbol and then look up the
         line information we'll actually return the line number for the
         opening '{' rather than the function definition line.  This is
         because looking up by symbol uses the line table, in which the
         first line for a function is usually the opening '{', while
         looking up the function by section + offset uses the
         DW_AT_decl_line from the function DW_TAG_subprogram for the line,
         which will be the line of the function name.  */
      if (symbols != NULL && (section->flags & SEC_CODE) == 0)
        {
          asymbol **tmp;

          for (tmp = symbols; (*tmp) != NULL; ++tmp)
            if ((*tmp)->the_bfd == abfd
                && (*tmp)->section == section
                && (*tmp)->value == offset
                && ((*tmp)->flags & BSF_SECTION_SYM) == 0)
              {
                symbol = *tmp;
                do_line = true;
                /* For local symbols, keep going in the hope we find a
                   global.  */
                if ((symbol->flags & BSF_GLOBAL) != 0)
                  break;
              }
        }
    }

  if (section->output_section)
    addr += section->output_section->vma + section->output_offset;
  else
    addr += section->vma;

  /* A null info_ptr indicates that there is no dwarf2 info
     (or that an error occured while setting up the stash).  */
  if (! stash->f.info_ptr)
    return false;

  stash->inliner_chain = NULL;

  /* Check the previously read comp. units first.  */
  if (do_line)
    {
      /* The info hash tables use quite a bit of memory.  We may not want to
         always use them.  We use some heuristics to decide if and when to
         turn it on.  */
      if (stash->info_hash_status == STASH_INFO_HASH_OFF)
        stash_maybe_enable_info_hash_tables (abfd, stash);

      /* Keep info hash table up to date if they are available.  Note that we
         may disable the hash tables if there is any error duing update.  */
      if (stash->info_hash_status == STASH_INFO_HASH_ON)
        stash_maybe_update_info_hash_tables (stash);

      if (stash->info_hash_status == STASH_INFO_HASH_ON)
        {
          found = stash_find_line_fast (stash, symbol, addr, filename_ptr,
                                        linenumber_ptr);
          if (found)
            goto done;
        }
      else
        {
          /* Check the previously read comp. units first.  */
          for (each = stash->f.all_comp_units; each; each = each->next_unit)
            if ((symbol->flags & BSF_FUNCTION) == 0
                || each->arange.high == 0
                || comp_unit_contains_address (each, addr))
              {
                found = comp_unit_find_line (each, symbol, addr, filename_ptr,
                                             linenumber_ptr);
                if (found)
                  goto done;
              }
        }
    }
  else
    {
      bfd_vma min_range = (bfd_vma) -1;
      const char * local_filename = NULL;
      struct funcinfo *local_function = NULL;
      unsigned int local_linenumber = 0;
      unsigned int local_discriminator = 0;

      for (each = stash->f.all_comp_units; each; each = each->next_unit)
        {
          bfd_vma range = (bfd_vma) -1;

          found = ((each->arange.high == 0
                    || comp_unit_contains_address (each, addr))
                   && (range = (comp_unit_find_nearest_line
                                (each, addr, &local_filename,
                                 &local_function, &local_linenumber,
                                 &local_discriminator))) != 0);
          if (found)
            {
              /* PRs 15935 15994: Bogus debug information may have provided us
                 with an erroneous match.  We attempt to counter this by
                 selecting the match that has the smallest address range
                 associated with it.  (We are assuming that corrupt debug info
                 will tend to result in extra large address ranges rather than
                 extra small ranges).

                 This does mean that we scan through all of the CUs associated
                 with the bfd each time this function is called.  But this does
                 have the benefit of producing consistent results every time the
                 function is called.  */
              if (range <= min_range)
                {
                  if (filename_ptr && local_filename)
                    * filename_ptr = local_filename;
                  if (local_function)
                    function = local_function;
                  if (discriminator_ptr && local_discriminator)
                    * discriminator_ptr = local_discriminator;
                  if (local_linenumber)
                    * linenumber_ptr = local_linenumber;
                  min_range = range;
                }
            }
        }

      if (* linenumber_ptr)
        {
          found = true;
          goto done;
        }
    }

  /* Read each remaining comp. units checking each as they are read.  */
  while ((each = stash_comp_unit (stash, &stash->f)) != NULL)
    {
      /* DW_AT_low_pc and DW_AT_high_pc are optional for
         compilation units.  If we don't have them (i.e.,
         unit->high == 0), we need to consult the line info table
         to see if a compilation unit contains the given
         address.  */
      if (do_line)
        found = (((symbol->flags & BSF_FUNCTION) == 0
                  || each->arange.high == 0
                  || comp_unit_contains_address (each, addr))
                 && comp_unit_find_line (each, symbol, addr,
                                         filename_ptr, linenumber_ptr));
      else
        found = ((each->arange.high == 0
                  || comp_unit_contains_address (each, addr))
                 && comp_unit_find_nearest_line (each, addr,
                                                 filename_ptr,
                                                 &function,
                                                 linenumber_ptr,
                                                 discriminator_ptr) != 0);

      if (found)
        break;
    }

 done:
  if (functionname_ptr && function && function->is_linkage)
    *functionname_ptr = function->name;
  else if (functionname_ptr
           && (!*functionname_ptr
               || (function && !function->is_linkage)))
    {
      asymbol *fun;
      asymbol **syms = symbols;
      asection *sec = section;

      _bfd_dwarf2_stash_syms (stash, abfd, &sec, &syms);
      fun = _bfd_elf_find_function (abfd, syms, sec, offset,
                                    *filename_ptr ? NULL : filename_ptr,
                                    functionname_ptr);

      if (!found && fun != NULL)
        found = 2;

      if (function && !function->is_linkage)
        {
          bfd_vma sec_vma;

          sec_vma = section->vma;
          if (section->output_section != NULL)
            sec_vma = section->output_section->vma + section->output_offset;
          if (fun != NULL
              && fun->value + sec_vma == function->arange.low)
            function->name = *functionname_ptr;
          /* Even if we didn't find a linkage name, say that we have
             to stop a repeated search of symbols.  */
          function->is_linkage = true;
        }
    }

  if ((abfd->flags & (EXEC_P | DYNAMIC)) == 0)
    unset_sections (stash);

  return found;
}

bool
_bfd_dwarf2_find_inliner_info (bfd *abfd ATTRIBUTE_UNUSED,
                               const char **filename_ptr,
                               const char **functionname_ptr,
                               unsigned int *linenumber_ptr,
                               void **pinfo)
{
  struct dwarf2_debug *stash;

  stash = (struct dwarf2_debug *) *pinfo;
  if (stash)
    {
      struct funcinfo *func = stash->inliner_chain;

      if (func && func->caller_func)
        {
          *filename_ptr = func->caller_file;
          *functionname_ptr = func->caller_func->name;
          *linenumber_ptr = func->caller_line;
          stash->inliner_chain = func->caller_func;
          return true;
        }
    }

  return false;
}

void
_bfd_dwarf2_cleanup_debug_info (bfd *abfd, void **pinfo)
{
  struct dwarf2_debug *stash = (struct dwarf2_debug *) *pinfo;
  struct comp_unit *each;
  struct dwarf2_debug_file *file;

  if (abfd == NULL || stash == NULL)
    return;

  if (stash->varinfo_hash_table)
    bfd_hash_table_free (&stash->varinfo_hash_table->base);
  if (stash->funcinfo_hash_table)
    bfd_hash_table_free (&stash->funcinfo_hash_table->base);

  file = &stash->f;
  while (1)
    {
      for (each = file->all_comp_units; each; each = each->next_unit)
        {
          struct funcinfo *function_table = each->function_table;
          struct varinfo *variable_table = each->variable_table;

          if (each->line_table && each->line_table != file->line_table)
            {
              free (each->line_table->files);
              free (each->line_table->dirs);
            }

          free (each->lookup_funcinfo_table);
          each->lookup_funcinfo_table = NULL;

          while (function_table)
            {
              free (function_table->file);
              function_table->file = NULL;
              free (function_table->caller_file);
              function_table->caller_file = NULL;
              function_table = function_table->prev_func;
            }

          while (variable_table)
            {
              free (variable_table->file);
              variable_table->file = NULL;
              variable_table = variable_table->prev_var;
            }
        }

      if (file->line_table)
        {
          free (file->line_table->files);
          free (file->line_table->dirs);
        }
      htab_delete (file->abbrev_offsets);

      free (file->dwarf_line_str_buffer);
      free (file->dwarf_str_buffer);
      free (file->dwarf_ranges_buffer);
      free (file->dwarf_line_buffer);
      free (file->dwarf_abbrev_buffer);
      free (file->dwarf_info_buffer);
      if (file == &stash->alt)
        break;
      file = &stash->alt;
    }
  free (stash->sec_vma);
  free (stash->adjusted_sections);
  if (stash->close_on_cleanup)
    bfd_close (stash->f.bfd_ptr);
  if (stash->alt.bfd_ptr)
    bfd_close (stash->alt.bfd_ptr);
}

/* Find the function to a particular section and offset,
   for error reporting.  */

asymbol *
_bfd_elf_find_function (bfd *abfd,
                        asymbol **symbols,
                        asection *section,
                        bfd_vma offset,
                        const char **filename_ptr,
                        const char **functionname_ptr)
{
  struct elf_find_function_cache
  {
    asection *last_section;
    asymbol *func;
    const char *filename;
    bfd_size_type func_size;
  } *cache;

  if (symbols == NULL)
    return NULL;

  if (bfd_get_flavour (abfd) != bfd_target_elf_flavour)
    return NULL;

  cache = elf_tdata (abfd)->elf_find_function_cache;
  if (cache == NULL)
    {
      cache = bfd_zalloc (abfd, sizeof (*cache));
      elf_tdata (abfd)->elf_find_function_cache = cache;
      if (cache == NULL)
        return NULL;
    }
  if (cache->last_section != section
      || cache->func == NULL
      || offset < cache->func->value
      || offset >= cache->func->value + cache->func_size)
    {
      asymbol *file;
      bfd_vma low_func;
      asymbol **p;
      /* ??? Given multiple file symbols, it is impossible to reliably
         choose the right file name for global symbols.  File symbols are
         local symbols, and thus all file symbols must sort before any
         global symbols.  The ELF spec may be interpreted to say that a
         file symbol must sort before other local symbols, but currently
         ld -r doesn't do this.  So, for ld -r output, it is possible to
         make a better choice of file name for local symbols by ignoring
         file symbols appearing after a given local symbol.  */
      enum { nothing_seen, symbol_seen, file_after_symbol_seen } state;
      const struct elf_backend_data *bed = get_elf_backend_data (abfd);

      file = NULL;
      low_func = 0;
      state = nothing_seen;
      cache->filename = NULL;
      cache->func = NULL;
      cache->func_size = 0;
      cache->last_section = section;

      for (p = symbols; *p != NULL; p++)
        {
          asymbol *sym = *p;
          bfd_vma code_off;
          bfd_size_type size;

          if ((sym->flags & BSF_FILE) != 0)
            {
              file = sym;
              if (state == symbol_seen)
                state = file_after_symbol_seen;
              continue;
            }

          size = bed->maybe_function_sym (sym, section, &code_off);
          if (size != 0
              && code_off <= offset
              && (code_off > low_func
                  || (code_off == low_func
                      && size > cache->func_size)))
            {
              cache->func = sym;
              cache->func_size = size;
              cache->filename = NULL;
              low_func = code_off;
              if (file != NULL
                  && ((sym->flags & BSF_LOCAL) != 0
                      || state != file_after_symbol_seen))
                cache->filename = bfd_asymbol_name (file);
            }
          if (state == nothing_seen)
            state = symbol_seen;
        }
    }

  if (cache->func == NULL)
    return NULL;

  if (filename_ptr)
    *filename_ptr = cache->filename;
  if (functionname_ptr)
    *functionname_ptr = bfd_asymbol_name (cache->func);

  return cache->func;
}