gcov*: collapse lisence header to 2 lines in --version.

[thirdparty/gcc.git] / gcc / lto-streamer-in.c

/* Read the GIMPLE representation from a file stream.

   Copyright (C) 2009-2020 Free Software Foundation, Inc.
   Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
   Re-implemented by Diego Novillo <dnovillo@google.com>

This file is part of GCC.

GCC 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, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "target.h"
#include "rtl.h"
#include "tree.h"
#include "gimple.h"
#include "cfghooks.h"
#include "tree-pass.h"
#include "ssa.h"
#include "gimple-streamer.h"
#include "toplev.h"
#include "gimple-iterator.h"
#include "tree-cfg.h"
#include "tree-into-ssa.h"
#include "tree-dfa.h"
#include "tree-ssa.h"
#include "except.h"
#include "cgraph.h"
#include "cfgloop.h"
#include "debug.h"
#include "alloc-pool.h"

/* Allocator used to hold string slot entries for line map streaming.  */
static struct object_allocator<struct string_slot> *string_slot_allocator;

/* The table to hold the file names.  */
static hash_table<string_slot_hasher> *file_name_hash_table;

/* This obstack holds file names used in locators. Line map datastructures
   points here and thus it needs to be kept allocated as long as linemaps
   exists.  */
static struct obstack file_name_obstack;


/* Check that tag ACTUAL has one of the given values.  NUM_TAGS is the
   number of valid tag values to check.  */

void
lto_tag_check_set (enum LTO_tags actual, int ntags, ...)
{
  va_list ap;
  int i;

  va_start (ap, ntags);
  for (i = 0; i < ntags; i++)
    if ((unsigned) actual == va_arg (ap, unsigned))
      {
        va_end (ap);
        return;
      }

  va_end (ap);
  internal_error ("bytecode stream: unexpected tag %s", lto_tag_name (actual));
}


/* Read LENGTH bytes from STREAM to ADDR.  */

void
lto_input_data_block (class lto_input_block *ib, void *addr, size_t length)
{
  size_t i;
  unsigned char *const buffer = (unsigned char *) addr;

  for (i = 0; i < length; i++)
    buffer[i] = streamer_read_uchar (ib);
}


/* Lookup STRING in file_name_hash_table.  If found, return the existing
   string, otherwise insert STRING as the canonical version.  */

static const char *
canon_file_name (const char *string)
{
  string_slot **slot;
  struct string_slot s_slot;
  size_t len = strlen (string);

  s_slot.s = string;
  s_slot.len = len;

  slot = file_name_hash_table->find_slot (&s_slot, INSERT);
  if (*slot == NULL)
    {
      char *saved_string;
      struct string_slot *new_slot;

      saved_string = XOBNEWVEC (&file_name_obstack, char, len + 1);
      new_slot = string_slot_allocator->allocate ();
      memcpy (saved_string, string, len + 1);
      new_slot->s = saved_string;
      new_slot->len = len;
      *slot = new_slot;
      return saved_string;
    }
  else
    {
      struct string_slot *old_slot = *slot;
      return old_slot->s;
    }
}

/* Pointer to currently alive instance of lto_location_cache.  */

lto_location_cache *lto_location_cache::current_cache;

/* Sort locations in source order. Start with file from last application.  */

int
lto_location_cache::cmp_loc (const void *pa, const void *pb)
{
  const cached_location *a = ((const cached_location *)pa);
  const cached_location *b = ((const cached_location *)pb);
  const char *current_file = current_cache->current_file;
  int current_line = current_cache->current_line;

  if (a->file == current_file && b->file != current_file)
    return -1;
  if (a->file != current_file && b->file == current_file)
    return 1;
  if (a->file == current_file && b->file == current_file)
    {
      if (a->line == current_line && b->line != current_line)
        return -1;
      if (a->line != current_line && b->line == current_line)
        return 1;
    }
  if (a->file != b->file)
    return strcmp (a->file, b->file);
  if (a->sysp != b->sysp)
    return a->sysp ? 1 : -1;
  if (a->line != b->line)
    return a->line - b->line;
  return a->col - b->col;
}

/* Apply all changes in location cache.  Add locations into linemap and patch
   trees.  */

bool
lto_location_cache::apply_location_cache ()
{
  static const char *prev_file;
  if (!loc_cache.length ())
    return false;
  if (loc_cache.length () > 1)
    loc_cache.qsort (cmp_loc);

  for (unsigned int i = 0; i < loc_cache.length (); i++)
    {
      struct cached_location loc = loc_cache[i];

      if (current_file != loc.file)
        linemap_add (line_table, prev_file ? LC_RENAME : LC_ENTER,
                     loc.sysp, loc.file, loc.line);
      else if (current_line != loc.line)
        {
          int max = loc.col;

          for (unsigned int j = i + 1; j < loc_cache.length (); j++)
            if (loc.file != loc_cache[j].file
                || loc.line != loc_cache[j].line)
              break;
            else if (max < loc_cache[j].col)
              max = loc_cache[j].col;
          linemap_line_start (line_table, loc.line, max + 1);
        }
      gcc_assert (*loc.loc == BUILTINS_LOCATION + 1);
      if (current_file == loc.file && current_line == loc.line
          && current_col == loc.col)
        *loc.loc = current_loc;
      else
        current_loc = *loc.loc = linemap_position_for_column (line_table,
                                                              loc.col);
      current_line = loc.line;
      prev_file = current_file = loc.file;
      current_col = loc.col;
    }
  loc_cache.truncate (0);
  accepted_length = 0;
  return true;
}

/* Tree merging did not suceed; mark all changes in the cache as accepted.  */

void
lto_location_cache::accept_location_cache ()
{
  gcc_assert (current_cache == this);
  accepted_length = loc_cache.length ();
}

/* Tree merging did suceed; throw away recent changes.  */

void
lto_location_cache::revert_location_cache ()
{
  loc_cache.truncate (accepted_length);
}

/* Read a location bitpack from input block IB and either update *LOC directly
   or add it to the location cache.
   It is neccesary to call apply_location_cache to get *LOC updated.  */

void
lto_location_cache::input_location (location_t *loc, struct bitpack_d *bp,
                                    class data_in *data_in)
{
  static const char *stream_file;
  static int stream_line;
  static int stream_col;
  static bool stream_sysp;
  bool file_change, line_change, column_change;

  gcc_assert (current_cache == this);

  *loc = bp_unpack_int_in_range (bp, "location", 0, RESERVED_LOCATION_COUNT);

  if (*loc < RESERVED_LOCATION_COUNT)
    return;

  /* Keep value RESERVED_LOCATION_COUNT in *loc as linemap lookups will
     ICE on it.  */

  file_change = bp_unpack_value (bp, 1);
  line_change = bp_unpack_value (bp, 1);
  column_change = bp_unpack_value (bp, 1);

  if (file_change)
    {
      stream_file = canon_file_name (bp_unpack_string (data_in, bp));
      stream_sysp = bp_unpack_value (bp, 1);
    }

  if (line_change)
    stream_line = bp_unpack_var_len_unsigned (bp);

  if (column_change)
    stream_col = bp_unpack_var_len_unsigned (bp);

  /* This optimization saves location cache operations druing gimple
     streaming.  */
     
  if (current_file == stream_file && current_line == stream_line
      && current_col == stream_col && current_sysp == stream_sysp)
    {
      *loc = current_loc;
      return;
    }

  struct cached_location entry
    = {stream_file, loc, stream_line, stream_col, stream_sysp};
  loc_cache.safe_push (entry);
}

/* Read a location bitpack from input block IB and either update *LOC directly
   or add it to the location cache.
   It is neccesary to call apply_location_cache to get *LOC updated.  */

void
lto_input_location (location_t *loc, struct bitpack_d *bp,
                    class data_in *data_in)
{
  data_in->location_cache.input_location (loc, bp, data_in);
}

/* Read location and return it instead of going through location caching.
   This should be used only when the resulting location is not going to be
   discarded.  */

location_t
stream_input_location_now (struct bitpack_d *bp, class data_in *data_in)
{
  location_t loc;
  stream_input_location (&loc, bp, data_in);
  data_in->location_cache.apply_location_cache ();
  return loc;
}

/* Read a reference to a tree node from DATA_IN using input block IB.
   TAG is the expected node that should be found in IB, if TAG belongs
   to one of the indexable trees, expect to read a reference index to
   be looked up in one of the symbol tables, otherwise read the pysical
   representation of the tree using stream_read_tree.  FN is the
   function scope for the read tree.  */

tree
lto_input_tree_ref (class lto_input_block *ib, class data_in *data_in,
                    struct function *fn, enum LTO_tags tag)
{
  unsigned HOST_WIDE_INT ix_u;
  tree result = NULL_TREE;

  if (tag == LTO_ssa_name_ref)
    {
      ix_u = streamer_read_uhwi (ib);
      result = (*SSANAMES (fn))[ix_u];
    }
  else
    {
      gcc_checking_assert (tag == LTO_global_stream_ref);
      ix_u = streamer_read_uhwi (ib);
      result = (*data_in->file_data->current_decl_state
                ->streams[LTO_DECL_STREAM])[ix_u];
    }

  gcc_assert (result);

  return result;
}

/* Read VAR_DECL reference to DATA from IB.  */

tree
lto_input_var_decl_ref (lto_input_block *ib, lto_file_decl_data *file_data)
{
  unsigned int ix_u = streamer_read_uhwi (ib);
  tree result = (*file_data->current_decl_state
                 ->streams[LTO_DECL_STREAM])[ix_u];
  gcc_assert (TREE_CODE (result) == VAR_DECL);
  return result;
}

/* Read VAR_DECL reference to DATA from IB.  */

tree
lto_input_fn_decl_ref (lto_input_block *ib, lto_file_decl_data *file_data)
{
  unsigned int ix_u = streamer_read_uhwi (ib);
  tree result = (*file_data->current_decl_state
                 ->streams[LTO_DECL_STREAM])[ix_u];
  gcc_assert (TREE_CODE (result) == FUNCTION_DECL);
  return result;
}


/* Read and return a double-linked list of catch handlers from input
   block IB, using descriptors in DATA_IN.  */

static struct eh_catch_d *
lto_input_eh_catch_list (class lto_input_block *ib, class data_in *data_in,
                         eh_catch *last_p)
{
  eh_catch first;
  enum LTO_tags tag;

  *last_p = first = NULL;
  tag = streamer_read_record_start (ib);
  while (tag)
    {
      tree list;
      eh_catch n;

      lto_tag_check_range (tag, LTO_eh_catch, LTO_eh_catch);

      /* Read the catch node.  */
      n = ggc_cleared_alloc<eh_catch_d> ();
      n->type_list = stream_read_tree (ib, data_in);
      n->filter_list = stream_read_tree (ib, data_in);
      n->label = stream_read_tree (ib, data_in);

      /* Register all the types in N->FILTER_LIST.  */
      for (list = n->filter_list; list; list = TREE_CHAIN (list))
        add_type_for_runtime (TREE_VALUE (list));

      /* Chain N to the end of the list.  */
      if (*last_p)
        (*last_p)->next_catch = n;
      n->prev_catch = *last_p;
      *last_p = n;

      /* Set the head of the list the first time through the loop.  */
      if (first == NULL)
        first = n;

      tag = streamer_read_record_start (ib);
    }

  return first;
}


/* Read and return EH region IX from input block IB, using descriptors
   in DATA_IN.  */

static eh_region
input_eh_region (class lto_input_block *ib, class data_in *data_in, int ix)
{
  enum LTO_tags tag;
  eh_region r;

  /* Read the region header.  */
  tag = streamer_read_record_start (ib);
  if (tag == LTO_null)
    return NULL;

  r = ggc_cleared_alloc<eh_region_d> ();
  r->index = streamer_read_hwi (ib);

  gcc_assert (r->index == ix);

  /* Read all the region pointers as region numbers.  We'll fix up
     the pointers once the whole array has been read.  */
  r->outer = (eh_region) (intptr_t) streamer_read_hwi (ib);
  r->inner = (eh_region) (intptr_t) streamer_read_hwi (ib);
  r->next_peer = (eh_region) (intptr_t) streamer_read_hwi (ib);

  switch (tag)
    {
      case LTO_ert_cleanup:
        r->type = ERT_CLEANUP;
        break;

      case LTO_ert_try:
        {
          struct eh_catch_d *last_catch;
          r->type = ERT_TRY;
          r->u.eh_try.first_catch = lto_input_eh_catch_list (ib, data_in,
                                                             &last_catch);
          r->u.eh_try.last_catch = last_catch;
          break;
        }

      case LTO_ert_allowed_exceptions:
        {
          tree l;

          r->type = ERT_ALLOWED_EXCEPTIONS;
          r->u.allowed.type_list = stream_read_tree (ib, data_in);
          r->u.allowed.label = stream_read_tree (ib, data_in);
          r->u.allowed.filter = streamer_read_uhwi (ib);

          for (l = r->u.allowed.type_list; l ; l = TREE_CHAIN (l))
            add_type_for_runtime (TREE_VALUE (l));
        }
        break;

      case LTO_ert_must_not_throw:
        {
          r->type = ERT_MUST_NOT_THROW;
          r->u.must_not_throw.failure_decl = stream_read_tree (ib, data_in);
          bitpack_d bp = streamer_read_bitpack (ib);
          r->u.must_not_throw.failure_loc
           = stream_input_location_now (&bp, data_in);
        }
        break;

      default:
        gcc_unreachable ();
    }

  r->landing_pads = (eh_landing_pad) (intptr_t) streamer_read_hwi (ib);

  return r;
}


/* Read and return EH landing pad IX from input block IB, using descriptors
   in DATA_IN.  */

static eh_landing_pad
input_eh_lp (class lto_input_block *ib, class data_in *data_in, int ix)
{
  enum LTO_tags tag;
  eh_landing_pad lp;

  /* Read the landing pad header.  */
  tag = streamer_read_record_start (ib);
  if (tag == LTO_null)
    return NULL;

  lto_tag_check_range (tag, LTO_eh_landing_pad, LTO_eh_landing_pad);

  lp = ggc_cleared_alloc<eh_landing_pad_d> ();
  lp->index = streamer_read_hwi (ib);
  gcc_assert (lp->index == ix);
  lp->next_lp = (eh_landing_pad) (intptr_t) streamer_read_hwi (ib);
  lp->region = (eh_region) (intptr_t) streamer_read_hwi (ib);
  lp->post_landing_pad = stream_read_tree (ib, data_in);

  return lp;
}


/* After reading the EH regions, pointers to peer and children regions
   are region numbers.  This converts all these region numbers into
   real pointers into the rematerialized regions for FN.  ROOT_REGION
   is the region number for the root EH region in FN.  */

static void
fixup_eh_region_pointers (struct function *fn, HOST_WIDE_INT root_region)
{
  unsigned i;
  vec<eh_region, va_gc> *eh_array = fn->eh->region_array;
  vec<eh_landing_pad, va_gc> *lp_array = fn->eh->lp_array;
  eh_region r;
  eh_landing_pad lp;

  gcc_assert (eh_array && lp_array);

  gcc_assert (root_region >= 0);
  fn->eh->region_tree = (*eh_array)[root_region];

#define FIXUP_EH_REGION(r) (r) = (*eh_array)[(HOST_WIDE_INT) (intptr_t) (r)]
#define FIXUP_EH_LP(p) (p) = (*lp_array)[(HOST_WIDE_INT) (intptr_t) (p)]

  /* Convert all the index numbers stored in pointer fields into
     pointers to the corresponding slots in the EH region array.  */
  FOR_EACH_VEC_ELT (*eh_array, i, r)
    {
      /* The array may contain NULL regions.  */
      if (r == NULL)
        continue;

      gcc_assert (i == (unsigned) r->index);
      FIXUP_EH_REGION (r->outer);
      FIXUP_EH_REGION (r->inner);
      FIXUP_EH_REGION (r->next_peer);
      FIXUP_EH_LP (r->landing_pads);
    }

  /* Convert all the index numbers stored in pointer fields into
     pointers to the corresponding slots in the EH landing pad array.  */
  FOR_EACH_VEC_ELT (*lp_array, i, lp)
    {
      /* The array may contain NULL landing pads.  */
      if (lp == NULL)
        continue;

      gcc_assert (i == (unsigned) lp->index);
      FIXUP_EH_LP (lp->next_lp);
      FIXUP_EH_REGION (lp->region);
    }

#undef FIXUP_EH_REGION
#undef FIXUP_EH_LP
}


/* Initialize EH support.  */

void
lto_init_eh (void)
{
  static bool eh_initialized_p = false;

  if (eh_initialized_p)
    return;

  /* Contrary to most other FEs, we only initialize EH support when at
     least one of the files in the set contains exception regions in
     it.  Since this happens much later than the call to init_eh in
     lang_dependent_init, we have to set flag_exceptions and call
     init_eh again to initialize the EH tables.  */
  flag_exceptions = 1;
  init_eh ();

  eh_initialized_p = true;
}


/* Read the exception table for FN from IB using the data descriptors
   in DATA_IN.  */

static void
input_eh_regions (class lto_input_block *ib, class data_in *data_in,
                  struct function *fn)
{
  HOST_WIDE_INT i, root_region, len;
  enum LTO_tags tag;

  tag = streamer_read_record_start (ib);
  if (tag == LTO_null)
    return;

  lto_tag_check_range (tag, LTO_eh_table, LTO_eh_table);

  gcc_assert (fn->eh);

  root_region = streamer_read_hwi (ib);
  gcc_assert (root_region == (int) root_region);

  /* Read the EH region array.  */
  len = streamer_read_hwi (ib);
  gcc_assert (len == (int) len);
  if (len > 0)
    {
      vec_safe_grow_cleared (fn->eh->region_array, len);
      for (i = 0; i < len; i++)
        {
          eh_region r = input_eh_region (ib, data_in, i);
          (*fn->eh->region_array)[i] = r;
        }
    }

  /* Read the landing pads.  */
  len = streamer_read_hwi (ib);
  gcc_assert (len == (int) len);
  if (len > 0)
    {
      vec_safe_grow_cleared (fn->eh->lp_array, len);
      for (i = 0; i < len; i++)
        {
          eh_landing_pad lp = input_eh_lp (ib, data_in, i);
          (*fn->eh->lp_array)[i] = lp;
        }
    }

  /* Read the runtime type data.  */
  len = streamer_read_hwi (ib);
  gcc_assert (len == (int) len);
  if (len > 0)
    {
      vec_safe_grow_cleared (fn->eh->ttype_data, len);
      for (i = 0; i < len; i++)
        {
          tree ttype = stream_read_tree (ib, data_in);
          (*fn->eh->ttype_data)[i] = ttype;
        }
    }

  /* Read the table of action chains.  */
  len = streamer_read_hwi (ib);
  gcc_assert (len == (int) len);
  if (len > 0)
    {
      if (targetm.arm_eabi_unwinder)
        {
          vec_safe_grow_cleared (fn->eh->ehspec_data.arm_eabi, len);
          for (i = 0; i < len; i++)
            {
              tree t = stream_read_tree (ib, data_in);
              (*fn->eh->ehspec_data.arm_eabi)[i] = t;
            }
        }
      else
        {
          vec_safe_grow_cleared (fn->eh->ehspec_data.other, len);
          for (i = 0; i < len; i++)
            {
              uchar c = streamer_read_uchar (ib);
              (*fn->eh->ehspec_data.other)[i] = c;
            }
        }
    }

  /* Reconstruct the EH region tree by fixing up the peer/children
     pointers.  */
  fixup_eh_region_pointers (fn, root_region);

  tag = streamer_read_record_start (ib);
  lto_tag_check_range (tag, LTO_null, LTO_null);
}


/* Make a new basic block with index INDEX in function FN.  */

static basic_block
make_new_block (struct function *fn, unsigned int index)
{
  basic_block bb = alloc_block ();
  bb->index = index;
  SET_BASIC_BLOCK_FOR_FN (fn, index, bb);
  n_basic_blocks_for_fn (fn)++;
  return bb;
}


/* Read the CFG for function FN from input block IB.  */

static void
input_cfg (class lto_input_block *ib, class data_in *data_in,
           struct function *fn)
{
  unsigned int bb_count;
  basic_block p_bb;
  unsigned int i;
  int index;

  init_empty_tree_cfg_for_function (fn);
  init_ssa_operands (fn);

  profile_status_for_fn (fn) = streamer_read_enum (ib, profile_status_d,
                                                   PROFILE_LAST);

  bb_count = streamer_read_uhwi (ib);

  last_basic_block_for_fn (fn) = bb_count;
  if (bb_count > basic_block_info_for_fn (fn)->length ())
    vec_safe_grow_cleared (basic_block_info_for_fn (fn), bb_count);

  if (bb_count > label_to_block_map_for_fn (fn)->length ())
    vec_safe_grow_cleared (label_to_block_map_for_fn (fn), bb_count);

  index = streamer_read_hwi (ib);
  while (index != -1)
    {
      basic_block bb = BASIC_BLOCK_FOR_FN (fn, index);
      unsigned int edge_count;

      if (bb == NULL)
        bb = make_new_block (fn, index);

      edge_count = streamer_read_uhwi (ib);

      /* Connect up the CFG.  */
      for (i = 0; i < edge_count; i++)
        {
          unsigned int dest_index;
          unsigned int edge_flags;
          basic_block dest;
          profile_probability probability;
          edge e;

          dest_index = streamer_read_uhwi (ib);
          probability = profile_probability::stream_in (ib);
          edge_flags = streamer_read_uhwi (ib);

          dest = BASIC_BLOCK_FOR_FN (fn, dest_index);

          if (dest == NULL)
            dest = make_new_block (fn, dest_index);

          e = make_edge (bb, dest, edge_flags);
          e->probability = probability;
        }

      index = streamer_read_hwi (ib);
    }

  p_bb = ENTRY_BLOCK_PTR_FOR_FN (fn);
  index = streamer_read_hwi (ib);
  while (index != -1)
    {
      basic_block bb = BASIC_BLOCK_FOR_FN (fn, index);
      bb->prev_bb = p_bb;
      p_bb->next_bb = bb;
      p_bb = bb;
      index = streamer_read_hwi (ib);
    }

  /* ???  The cfgloop interface is tied to cfun.  */
  gcc_assert (cfun == fn);

  /* Input the loop tree.  */
  unsigned n_loops = streamer_read_uhwi (ib);
  if (n_loops == 0)
    return;

  struct loops *loops = ggc_cleared_alloc<struct loops> ();
  init_loops_structure (fn, loops, n_loops);
  set_loops_for_fn (fn, loops);

  /* Input each loop and associate it with its loop header so
     flow_loops_find can rebuild the loop tree.  */
  for (unsigned i = 1; i < n_loops; ++i)
    {
      int header_index = streamer_read_hwi (ib);
      if (header_index == -1)
        {
          loops->larray->quick_push (NULL);
          continue;
        }

      class loop *loop = alloc_loop ();
      loop->header = BASIC_BLOCK_FOR_FN (fn, header_index);
      loop->header->loop_father = loop;

      /* Read everything copy_loop_info copies.  */
      loop->estimate_state = streamer_read_enum (ib, loop_estimation, EST_LAST);
      loop->any_upper_bound = streamer_read_hwi (ib);
      if (loop->any_upper_bound)
        loop->nb_iterations_upper_bound = streamer_read_widest_int (ib);
      loop->any_likely_upper_bound = streamer_read_hwi (ib);
      if (loop->any_likely_upper_bound)
        loop->nb_iterations_likely_upper_bound = streamer_read_widest_int (ib);
      loop->any_estimate = streamer_read_hwi (ib);
      if (loop->any_estimate)
        loop->nb_iterations_estimate = streamer_read_widest_int (ib);

      /* Read OMP SIMD related info.  */
      loop->safelen = streamer_read_hwi (ib);
      loop->unroll = streamer_read_hwi (ib);
      loop->owned_clique = streamer_read_hwi (ib);
      loop->dont_vectorize = streamer_read_hwi (ib);
      loop->force_vectorize = streamer_read_hwi (ib);
      loop->finite_p = streamer_read_hwi (ib);
      loop->simduid = stream_read_tree (ib, data_in);

      place_new_loop (fn, loop);

      /* flow_loops_find doesn't like loops not in the tree, hook them
         all as siblings of the tree root temporarily.  */
      flow_loop_tree_node_add (loops->tree_root, loop);
    }

  /* Rebuild the loop tree.  */
  flow_loops_find (loops);
}


/* Read the SSA names array for function FN from DATA_IN using input
   block IB.  */

static void
input_ssa_names (class lto_input_block *ib, class data_in *data_in,
                 struct function *fn)
{
  unsigned int i, size;

  size = streamer_read_uhwi (ib);
  init_ssanames (fn, size);

  i = streamer_read_uhwi (ib);
  while (i)
    {
      tree ssa_name, name;
      bool is_default_def;

      /* Skip over the elements that had been freed.  */
      while (SSANAMES (fn)->length () < i)
        SSANAMES (fn)->quick_push (NULL_TREE);

      is_default_def = (streamer_read_uchar (ib) != 0);
      name = stream_read_tree (ib, data_in);
      ssa_name = make_ssa_name_fn (fn, name, NULL);

      if (is_default_def)
        {
          set_ssa_default_def (cfun, SSA_NAME_VAR (ssa_name), ssa_name);
          SSA_NAME_DEF_STMT (ssa_name) = gimple_build_nop ();
        }

      i = streamer_read_uhwi (ib);
    }
}


/* Go through all NODE edges and fixup call_stmt pointers
   so they point to STMTS.  */

static void
fixup_call_stmt_edges_1 (struct cgraph_node *node, gimple **stmts,
                         struct function *fn)
{
#define STMT_UID_NOT_IN_RANGE(uid) \
  (gimple_stmt_max_uid (fn) < uid || uid == 0)

  struct cgraph_edge *cedge;
  struct ipa_ref *ref = NULL;
  unsigned int i;

  for (cedge = node->callees; cedge; cedge = cedge->next_callee)
    {
      if (STMT_UID_NOT_IN_RANGE (cedge->lto_stmt_uid))
        fatal_error (input_location,
                     "Cgraph edge statement index out of range");
      cedge->call_stmt = as_a <gcall *> (stmts[cedge->lto_stmt_uid - 1]);
      cedge->lto_stmt_uid = 0;
      if (!cedge->call_stmt)
        fatal_error (input_location,
                     "Cgraph edge statement index not found");
    }
  for (cedge = node->indirect_calls; cedge; cedge = cedge->next_callee)
    {
      if (STMT_UID_NOT_IN_RANGE (cedge->lto_stmt_uid))
        fatal_error (input_location,
                     "Cgraph edge statement index out of range");
      cedge->call_stmt = as_a <gcall *> (stmts[cedge->lto_stmt_uid - 1]);
      cedge->lto_stmt_uid = 0;
      if (!cedge->call_stmt)
        fatal_error (input_location, "Cgraph edge statement index not found");
    }
  for (i = 0; node->iterate_reference (i, ref); i++)
    if (ref->lto_stmt_uid)
      {
        if (STMT_UID_NOT_IN_RANGE (ref->lto_stmt_uid))
          fatal_error (input_location,
                       "Reference statement index out of range");
        ref->stmt = stmts[ref->lto_stmt_uid - 1];
        ref->lto_stmt_uid = 0;
        if (!ref->stmt)
          fatal_error (input_location, "Reference statement index not found");
      }
}


/* Fixup call_stmt pointers in NODE and all clones.  */

static void
fixup_call_stmt_edges (struct cgraph_node *orig, gimple **stmts)
{
  struct cgraph_node *node;
  struct function *fn;

  while (orig->clone_of)
    orig = orig->clone_of;
  fn = DECL_STRUCT_FUNCTION (orig->decl);

  if (!orig->thunk.thunk_p)
    fixup_call_stmt_edges_1 (orig, stmts, fn);
  if (orig->clones)
    for (node = orig->clones; node != orig;)
      {
        if (!node->thunk.thunk_p)
          fixup_call_stmt_edges_1 (node, stmts, fn);
        if (node->clones)
          node = node->clones;
        else if (node->next_sibling_clone)
          node = node->next_sibling_clone;
        else
          {
            while (node != orig && !node->next_sibling_clone)
              node = node->clone_of;
            if (node != orig)
              node = node->next_sibling_clone;
          }
      }
}


/* Input the base body of struct function FN from DATA_IN
   using input block IB.  */

static void
input_struct_function_base (struct function *fn, class data_in *data_in,
                            class lto_input_block *ib)
{
  struct bitpack_d bp;
  int len;

  /* Read the static chain and non-local goto save area.  */
  fn->static_chain_decl = stream_read_tree (ib, data_in);
  fn->nonlocal_goto_save_area = stream_read_tree (ib, data_in);

  /* Read all the local symbols.  */
  len = streamer_read_hwi (ib);
  if (len > 0)
    {
      int i;
      vec_safe_grow_cleared (fn->local_decls, len);
      for (i = 0; i < len; i++)
        {
          tree t = stream_read_tree (ib, data_in);
          (*fn->local_decls)[i] = t;
        }
    }

  /* Input the current IL state of the function.  */
  fn->curr_properties = streamer_read_uhwi (ib);

  /* Read all the attributes for FN.  */
  bp = streamer_read_bitpack (ib);
  fn->is_thunk = bp_unpack_value (&bp, 1);
  fn->has_local_explicit_reg_vars = bp_unpack_value (&bp, 1);
  fn->returns_pcc_struct = bp_unpack_value (&bp, 1);
  fn->returns_struct = bp_unpack_value (&bp, 1);
  fn->can_throw_non_call_exceptions = bp_unpack_value (&bp, 1);
  fn->can_delete_dead_exceptions = bp_unpack_value (&bp, 1);
  fn->always_inline_functions_inlined = bp_unpack_value (&bp, 1);
  fn->after_inlining = bp_unpack_value (&bp, 1);
  fn->stdarg = bp_unpack_value (&bp, 1);
  fn->has_nonlocal_label = bp_unpack_value (&bp, 1);
  fn->has_forced_label_in_static = bp_unpack_value (&bp, 1);
  fn->calls_alloca = bp_unpack_value (&bp, 1);
  fn->calls_setjmp = bp_unpack_value (&bp, 1);
  fn->calls_eh_return = bp_unpack_value (&bp, 1);
  fn->has_force_vectorize_loops = bp_unpack_value (&bp, 1);
  fn->has_simduid_loops = bp_unpack_value (&bp, 1);
  fn->va_list_fpr_size = bp_unpack_value (&bp, 8);
  fn->va_list_gpr_size = bp_unpack_value (&bp, 8);
  fn->last_clique = bp_unpack_value (&bp, sizeof (short) * 8);

  /* Input the function start and end loci.  */
  fn->function_start_locus = stream_input_location_now (&bp, data_in);
  fn->function_end_locus = stream_input_location_now (&bp, data_in);

  /* Restore the instance discriminators if present.  */
  int instance_number = bp_unpack_value (&bp, 1);
  if (instance_number)
    {
      instance_number = bp_unpack_value (&bp, sizeof (int) * CHAR_BIT);
      maybe_create_decl_to_instance_map ()->put (fn->decl, instance_number);
    }
}

/* Read a chain of tree nodes from input block IB.  DATA_IN contains
   tables and descriptors for the file being read.  */

static tree
streamer_read_chain (class lto_input_block *ib, class data_in *data_in)
{
  tree first, prev, curr;

  /* The chain is written as NULL terminated list of trees.  */
  first = prev = NULL_TREE;
  do
    {
      curr = stream_read_tree (ib, data_in);
      if (prev)
        TREE_CHAIN (prev) = curr;
      else
        first = curr;

      prev = curr;
    }
  while (curr);

  return first;
}

/* Read the body of function FN_DECL from DATA_IN using input block IB.  */

static void
input_function (tree fn_decl, class data_in *data_in,
                class lto_input_block *ib, class lto_input_block *ib_cfg,
                cgraph_node *node)
{
  struct function *fn;
  enum LTO_tags tag;
  gimple **stmts;
  basic_block bb;

  tag = streamer_read_record_start (ib);
  lto_tag_check (tag, LTO_function);

  /* Read decls for parameters and args.  */
  DECL_RESULT (fn_decl) = stream_read_tree (ib, data_in);
  DECL_ARGUMENTS (fn_decl) = streamer_read_chain (ib, data_in);

  /* Read debug args if available.  */
  unsigned n_debugargs = streamer_read_uhwi (ib);
  if (n_debugargs)
    {
      vec<tree, va_gc> **debugargs = decl_debug_args_insert (fn_decl);
      vec_safe_grow (*debugargs, n_debugargs);
      for (unsigned i = 0; i < n_debugargs; ++i)
        (**debugargs)[i] = stream_read_tree (ib, data_in);
    }

  /* Read the tree of lexical scopes for the function.  */
  DECL_INITIAL (fn_decl) = stream_read_tree (ib, data_in);
  unsigned block_leaf_count = streamer_read_uhwi (ib);
  while (block_leaf_count--)
    stream_read_tree (ib, data_in);

  if (!streamer_read_uhwi (ib))
    return;

  push_struct_function (fn_decl);
  fn = DECL_STRUCT_FUNCTION (fn_decl);
  init_tree_ssa (fn);
  /* We input IL in SSA form.  */
  cfun->gimple_df->in_ssa_p = true;

  gimple_register_cfg_hooks ();

  input_struct_function_base (fn, data_in, ib);
  input_cfg (ib_cfg, data_in, fn);

  /* Read all the SSA names.  */
  input_ssa_names (ib, data_in, fn);

  /* Read the exception handling regions in the function.  */
  input_eh_regions (ib, data_in, fn);

  gcc_assert (DECL_INITIAL (fn_decl));
  DECL_SAVED_TREE (fn_decl) = NULL_TREE;

  /* Read all the basic blocks.  */
  tag = streamer_read_record_start (ib);
  while (tag)
    {
      input_bb (ib, tag, data_in, fn,
                node->count_materialization_scale);
      tag = streamer_read_record_start (ib);
    }

  /* Fix up the call statements that are mentioned in the callgraph
     edges.  */
  set_gimple_stmt_max_uid (cfun, 0);
  FOR_ALL_BB_FN (bb, cfun)
    {
      gimple_stmt_iterator gsi;
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          gimple *stmt = gsi_stmt (gsi);
          gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
        }
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          gimple *stmt = gsi_stmt (gsi);
          gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
        }
    }
  stmts = (gimple **) xcalloc (gimple_stmt_max_uid (fn), sizeof (gimple *));
  FOR_ALL_BB_FN (bb, cfun)
    {
      gimple_stmt_iterator bsi = gsi_start_phis (bb);
      while (!gsi_end_p (bsi))
        {
          gimple *stmt = gsi_stmt (bsi);
          gsi_next (&bsi);
          stmts[gimple_uid (stmt)] = stmt;
        }
      bsi = gsi_start_bb (bb);
      while (!gsi_end_p (bsi))
        {
          gimple *stmt = gsi_stmt (bsi);
          bool remove = false;
          /* If we're recompiling LTO objects with debug stmts but
             we're not supposed to have debug stmts, remove them now.
             We can't remove them earlier because this would cause uid
             mismatches in fixups, but we can do it at this point, as
             long as debug stmts don't require fixups.
             Similarly remove all IFN_*SAN_* internal calls   */
          if (!flag_wpa)
            {
              if (is_gimple_debug (stmt)
                  && (gimple_debug_nonbind_marker_p (stmt)
                      ? !MAY_HAVE_DEBUG_MARKER_STMTS
                      : !MAY_HAVE_DEBUG_BIND_STMTS))
                remove = true;
              /* In case the linemap overflows locations can be dropped
                 to zero.  Thus do not keep nonsensical inline entry markers
                 we'd later ICE on.  */
              tree block;
              if (gimple_debug_inline_entry_p (stmt)
                  && (((block = gimple_block (stmt))
                       && !inlined_function_outer_scope_p (block))
                      || !debug_inline_points))
                remove = true;
              if (is_gimple_call (stmt)
                  && gimple_call_internal_p (stmt))
                {
                  bool replace = false;
                  switch (gimple_call_internal_fn (stmt))
                    {
                    case IFN_UBSAN_NULL:
                      if ((flag_sanitize
                          & (SANITIZE_NULL | SANITIZE_ALIGNMENT)) == 0)
                        replace = true;
                      break;
                    case IFN_UBSAN_BOUNDS:
                      if ((flag_sanitize & SANITIZE_BOUNDS) == 0)
                        replace = true;
                      break;
                    case IFN_UBSAN_VPTR:
                      if ((flag_sanitize & SANITIZE_VPTR) == 0)
                        replace = true;
                      break;
                    case IFN_UBSAN_OBJECT_SIZE:
                      if ((flag_sanitize & SANITIZE_OBJECT_SIZE) == 0)
                        replace = true;
                      break;
                    case IFN_UBSAN_PTR:
                      if ((flag_sanitize & SANITIZE_POINTER_OVERFLOW) == 0)
                        replace = true;
                      break;
                    case IFN_ASAN_MARK:
                      if ((flag_sanitize & SANITIZE_ADDRESS) == 0)
                        replace = true;
                      break;
                    case IFN_TSAN_FUNC_EXIT:
                      if ((flag_sanitize & SANITIZE_THREAD) == 0)
                        replace = true;
                      break;
                    default:
                      break;
                    }
                  if (replace)
                    {
                      gimple_call_set_internal_fn (as_a <gcall *> (stmt),
                                                   IFN_NOP);
                      update_stmt (stmt);
                    }
                }
            }
          if (remove)
            {
              gimple_stmt_iterator gsi = bsi;
              gsi_next (&bsi);
              unlink_stmt_vdef (stmt);
              release_defs (stmt);
              gsi_remove (&gsi, true);
            }
          else
            {
              gsi_next (&bsi);
              stmts[gimple_uid (stmt)] = stmt;

              /* Remember that the input function has begin stmt
                 markers, so that we know to expect them when emitting
                 debug info.  */
              if (!cfun->debug_nonbind_markers
                  && gimple_debug_nonbind_marker_p (stmt))
                cfun->debug_nonbind_markers = true;
            }
        }
    }

  /* Set the gimple body to the statement sequence in the entry
     basic block.  FIXME lto, this is fairly hacky.  The existence
     of a gimple body is used by the cgraph routines, but we should
     really use the presence of the CFG.  */
  {
    edge_iterator ei = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs);
    gimple_set_body (fn_decl, bb_seq (ei_edge (ei)->dest));
  }

  update_max_bb_count ();
  fixup_call_stmt_edges (node, stmts);
  execute_all_ipa_stmt_fixups (node, stmts);

  free_dominance_info (CDI_DOMINATORS);
  free_dominance_info (CDI_POST_DOMINATORS);
  free (stmts);
  pop_cfun ();
}

/* Read the body of function FN_DECL from DATA_IN using input block IB.  */

static void
input_constructor (tree var, class data_in *data_in,
                   class lto_input_block *ib)
{
  DECL_INITIAL (var) = stream_read_tree (ib, data_in);
}


/* Read the body from DATA for function NODE and fill it in.
   FILE_DATA are the global decls and types.  SECTION_TYPE is either
   LTO_section_function_body or LTO_section_static_initializer.  If
   section type is LTO_section_function_body, FN must be the decl for
   that function.  */

static void
lto_read_body_or_constructor (struct lto_file_decl_data *file_data, struct symtab_node *node,
                              const char *data, enum lto_section_type section_type)
{
  const struct lto_function_header *header;
  class data_in *data_in;
  int cfg_offset;
  int main_offset;
  int string_offset;
  tree fn_decl = node->decl;

  header = (const struct lto_function_header *) data;
  if (TREE_CODE (node->decl) == FUNCTION_DECL)
    {
      cfg_offset = sizeof (struct lto_function_header);
      main_offset = cfg_offset + header->cfg_size;
      string_offset = main_offset + header->main_size;
    }
  else
    {
      main_offset = sizeof (struct lto_function_header);
      string_offset = main_offset + header->main_size;
    }

  data_in = lto_data_in_create (file_data, data + string_offset,
                              header->string_size, vNULL);

  if (section_type == LTO_section_function_body)
    {
      struct lto_in_decl_state *decl_state;
      unsigned from;

      gcc_checking_assert (node);

      /* Use the function's decl state. */
      decl_state = lto_get_function_in_decl_state (file_data, fn_decl);
      gcc_assert (decl_state);
      file_data->current_decl_state = decl_state;


      /* Set up the struct function.  */
      from = data_in->reader_cache->nodes.length ();
      lto_input_block ib_main (data + main_offset, header->main_size,
                               file_data->mode_table);
      if (TREE_CODE (node->decl) == FUNCTION_DECL)
        {
          lto_input_block ib_cfg (data + cfg_offset, header->cfg_size,
                                  file_data->mode_table);
          input_function (fn_decl, data_in, &ib_main, &ib_cfg,
                          dyn_cast <cgraph_node *>(node));
        }
      else
        input_constructor (fn_decl, data_in, &ib_main);
      data_in->location_cache.apply_location_cache ();
      /* And fixup types we streamed locally.  */
        {
          struct streamer_tree_cache_d *cache = data_in->reader_cache;
          unsigned len = cache->nodes.length ();
          unsigned i;
          for (i = len; i-- > from;)
            {
              tree t = streamer_tree_cache_get_tree (cache, i);
              if (t == NULL_TREE)
                continue;

              if (TYPE_P (t))
                {
                  gcc_assert (TYPE_CANONICAL (t) == NULL_TREE);
                  if (type_with_alias_set_p (t)
                      && canonical_type_used_p (t))
                    TYPE_CANONICAL (t) = TYPE_MAIN_VARIANT (t);
                  if (TYPE_MAIN_VARIANT (t) != t)
                    {
                      gcc_assert (TYPE_NEXT_VARIANT (t) == NULL_TREE);
                      TYPE_NEXT_VARIANT (t)
                        = TYPE_NEXT_VARIANT (TYPE_MAIN_VARIANT (t));
                      TYPE_NEXT_VARIANT (TYPE_MAIN_VARIANT (t)) = t;
                    }
                }
            }
        }

      /* Restore decl state */
      file_data->current_decl_state = file_data->global_decl_state;
    }

  lto_data_in_delete (data_in);
}


/* Read the body of NODE using DATA.  FILE_DATA holds the global
   decls and types.  */

void
lto_input_function_body (struct lto_file_decl_data *file_data,
                         struct cgraph_node *node, const char *data)
{
  lto_read_body_or_constructor (file_data, node, data, LTO_section_function_body);
}

/* Read the body of NODE using DATA.  FILE_DATA holds the global
   decls and types.  */

void
lto_input_variable_constructor (struct lto_file_decl_data *file_data,
                                struct varpool_node *node, const char *data)
{
  lto_read_body_or_constructor (file_data, node, data, LTO_section_function_body);
}


/* Queue of acummulated decl -> DIE mappings.  Similar to locations those
   are only applied to prevailing tree nodes during tree merging.  */
vec<dref_entry> dref_queue;

/* Read the physical representation of a tree node EXPR from
   input block IB using the per-file context in DATA_IN.  */

static void
lto_read_tree_1 (class lto_input_block *ib, class data_in *data_in, tree expr)
{
  /* Read all the bitfield values in EXPR.  Note that for LTO, we
     only write language-independent bitfields, so no more unpacking is
     needed.  */
  streamer_read_tree_bitfields (ib, data_in, expr);

  /* Read all the pointer fields in EXPR.  */
  streamer_read_tree_body (ib, data_in, expr);

  /* Read any LTO-specific data not read by the tree streamer.  */
  if (DECL_P (expr)
      && TREE_CODE (expr) != FUNCTION_DECL
      && TREE_CODE (expr) != TRANSLATION_UNIT_DECL)
    DECL_INITIAL (expr) = stream_read_tree (ib, data_in);

  /* Stream references to early generated DIEs.  Keep in sync with the
     trees handled in dwarf2out_register_external_die.  */
  if ((DECL_P (expr)
       && TREE_CODE (expr) != FIELD_DECL
       && TREE_CODE (expr) != DEBUG_EXPR_DECL
       && TREE_CODE (expr) != TYPE_DECL)
      || TREE_CODE (expr) == BLOCK)
    {
      const char *str = streamer_read_string (data_in, ib);
      if (str)
        {
          unsigned HOST_WIDE_INT off = streamer_read_uhwi (ib);
          dref_entry e = { expr, str, off };
          dref_queue.safe_push (e);
        }
    }
}

/* Read the physical representation of a tree node with tag TAG from
   input block IB using the per-file context in DATA_IN.  */

static tree
lto_read_tree (class lto_input_block *ib, class data_in *data_in,
               enum LTO_tags tag, hashval_t hash)
{
  /* Instantiate a new tree node.  */
  tree result = streamer_alloc_tree (ib, data_in, tag);

  /* Enter RESULT in the reader cache.  This will make RESULT
     available so that circular references in the rest of the tree
     structure can be resolved in subsequent calls to stream_read_tree.  */
  streamer_tree_cache_append (data_in->reader_cache, result, hash);

  lto_read_tree_1 (ib, data_in, result);

  return result;
}


/* Populate the reader cache with trees materialized from the SCC
   following in the IB, DATA_IN stream.
   If SHARED_SCC is true we input LTO_tree_scc.  */

hashval_t
lto_input_scc (class lto_input_block *ib, class data_in *data_in,
               unsigned *len, unsigned *entry_len, bool shared_scc)
{
  unsigned size = streamer_read_uhwi (ib);
  hashval_t scc_hash = 0;
  unsigned scc_entry_len = 1;

  if (shared_scc)
    {
      if (size & 1)
        scc_entry_len = streamer_read_uhwi (ib);
      size /= 2;
      scc_hash = streamer_read_uhwi (ib);
    }

  if (size == 1)
    {
      enum LTO_tags tag = streamer_read_record_start (ib);
      lto_input_tree_1 (ib, data_in, tag, scc_hash);
    }
  else
    {
      unsigned int first = data_in->reader_cache->nodes.length ();
      tree result;

      /* Materialize size trees by reading their headers.  */
      for (unsigned i = 0; i < size; ++i)
        {
          enum LTO_tags tag = streamer_read_record_start (ib);
          if (tag == LTO_null
              || tag == LTO_global_stream_ref
              || tag == LTO_tree_pickle_reference
              || tag == LTO_integer_cst
              || tag == LTO_tree_scc
              || tag == LTO_trees)
            gcc_unreachable ();

          result = streamer_alloc_tree (ib, data_in, tag);
          streamer_tree_cache_append (data_in->reader_cache, result, 0);
        }

      /* Read the tree bitpacks and references.  */
      for (unsigned i = 0; i < size; ++i)
        {
          result = streamer_tree_cache_get_tree (data_in->reader_cache,
                                                 first + i);
          lto_read_tree_1 (ib, data_in, result);
        }
    }

  *len = size;
  *entry_len = scc_entry_len;
  return scc_hash;
}

/* Read reference to tree from IB and DATA_IN.
   This is used for streaming tree bodies where we know that
   the tree is already in cache or is indexable and 
   must be matched with stream_write_tree_ref.  */

tree
stream_read_tree_ref (lto_input_block *ib, data_in *data_in)
{
  int ix = streamer_read_hwi (ib);
  if (!ix)
    return NULL_TREE;
  if (ix > 0)
    return streamer_tree_cache_get_tree (data_in->reader_cache, ix - 1);

  ix = -ix - 1;
  int id = ix & 1;
  ix /= 2;

  tree ret;
  if (!id)
    ret = (*data_in->file_data->current_decl_state
           ->streams[LTO_DECL_STREAM])[ix];
  else
    ret = (*SSANAMES (cfun))[ix];
  return ret;
}

/* Read a tree from input block IB using the per-file context in
   DATA_IN.  This context is used, for example, to resolve references
   to previously read nodes.  */

tree
lto_input_tree_1 (class lto_input_block *ib, class data_in *data_in,
                  enum LTO_tags tag, hashval_t hash)
{
  tree result;

  gcc_assert ((unsigned) tag < (unsigned) LTO_NUM_TAGS);

  if (tag == LTO_null)
    result = NULL_TREE;
  else if (tag == LTO_global_stream_ref || tag == LTO_ssa_name_ref)
    {
      /* If TAG is a reference to an indexable tree, the next value
         in IB is the index into the table where we expect to find
         that tree.  */
      result = lto_input_tree_ref (ib, data_in, cfun, tag);
    }
  else if (tag == LTO_tree_pickle_reference)
    {
      /* If TAG is a reference to a previously read tree, look it up in
         the reader cache.  */
      result = streamer_get_pickled_tree (ib, data_in);
    }
  else if (tag == LTO_integer_cst)
    {
      /* For shared integer constants in singletons we can use the
         existing tree integer constant merging code.  */
      tree type = stream_read_tree_ref (ib, data_in);
      unsigned HOST_WIDE_INT len = streamer_read_uhwi (ib);
      unsigned HOST_WIDE_INT i;
      HOST_WIDE_INT a[WIDE_INT_MAX_ELTS];

      for (i = 0; i < len; i++)
        a[i] = streamer_read_hwi (ib);
      gcc_assert (TYPE_PRECISION (type) <= MAX_BITSIZE_MODE_ANY_INT);
      result = wide_int_to_tree (type, wide_int::from_array
                                 (a, len, TYPE_PRECISION (type)));
      streamer_tree_cache_append (data_in->reader_cache, result, hash);
    }
  else if (tag == LTO_tree_scc || tag == LTO_trees)
    gcc_unreachable ();
  else
    {
      /* Otherwise, materialize a new node from IB.  */
      result = lto_read_tree (ib, data_in, tag, hash);
    }

  return result;
}

tree
lto_input_tree (class lto_input_block *ib, class data_in *data_in)
{
  enum LTO_tags tag;

  /* Input pickled trees needed to stream in the reference.  */
  while ((tag = streamer_read_record_start (ib)) == LTO_trees)
    {
      unsigned len, entry_len;
      lto_input_scc (ib, data_in, &len, &entry_len, false);

      /* Register DECLs with the debuginfo machinery.  */
      while (!dref_queue.is_empty ())
        {
          dref_entry e = dref_queue.pop ();
          debug_hooks->register_external_die (e.decl, e.sym, e.off);
        }
    }
  tree t = lto_input_tree_1 (ib, data_in, tag, 0);

  if (!dref_queue.is_empty ())
    {
      dref_entry e = dref_queue.pop ();
      debug_hooks->register_external_die (e.decl, e.sym, e.off);
      gcc_checking_assert (dref_queue.is_empty ());
    }
  return t;
}


/* Input toplevel asms.  */

void
lto_input_toplevel_asms (struct lto_file_decl_data *file_data, int order_base)
{
  size_t len;
  const char *data
    = lto_get_summary_section_data (file_data, LTO_section_asm, &len);
  const struct lto_simple_header_with_strings *header
    = (const struct lto_simple_header_with_strings *) data;
  int string_offset;
  class data_in *data_in;
  tree str;

  if (! data)
    return;

  string_offset = sizeof (*header) + header->main_size;

  lto_input_block ib (data + sizeof (*header), header->main_size,
                      file_data->mode_table);

  data_in = lto_data_in_create (file_data, data + string_offset,
                              header->string_size, vNULL);

  while ((str = streamer_read_string_cst (data_in, &ib)))
    {
      asm_node *node = symtab->finalize_toplevel_asm (str);
      node->order = streamer_read_hwi (&ib) + order_base;
      if (node->order >= symtab->order)
        symtab->order = node->order + 1;
    }

  lto_data_in_delete (data_in);

  lto_free_section_data (file_data, LTO_section_asm, NULL, data, len);
}


/* Input mode table.  */

void
lto_input_mode_table (struct lto_file_decl_data *file_data)
{
  size_t len;
  const char *data
    = lto_get_summary_section_data (file_data, LTO_section_mode_table, &len);
  if (! data)
    {
      internal_error ("cannot read LTO mode table from %s",
                      file_data->file_name);
      return;
    }

  unsigned char *table = ggc_cleared_vec_alloc<unsigned char> (1 << 8);
  file_data->mode_table = table;
  const struct lto_simple_header_with_strings *header
    = (const struct lto_simple_header_with_strings *) data;
  int string_offset;
  class data_in *data_in;
  string_offset = sizeof (*header) + header->main_size;

  lto_input_block ib (data + sizeof (*header), header->main_size, NULL);
  data_in = lto_data_in_create (file_data, data + string_offset,
                                header->string_size, vNULL);
  bitpack_d bp = streamer_read_bitpack (&ib);

  table[VOIDmode] = VOIDmode;
  table[BLKmode] = BLKmode;
  unsigned int m;
  while ((m = bp_unpack_value (&bp, 8)) != VOIDmode)
    {
      enum mode_class mclass
        = bp_unpack_enum (&bp, mode_class, MAX_MODE_CLASS);
      poly_uint16 size = bp_unpack_poly_value (&bp, 16);
      poly_uint16 prec = bp_unpack_poly_value (&bp, 16);
      machine_mode inner = (machine_mode) bp_unpack_value (&bp, 8);
      poly_uint16 nunits = bp_unpack_poly_value (&bp, 16);
      unsigned int ibit = 0, fbit = 0;
      unsigned int real_fmt_len = 0;
      const char *real_fmt_name = NULL;
      switch (mclass)
        {
        case MODE_FRACT:
        case MODE_UFRACT:
        case MODE_ACCUM:
        case MODE_UACCUM:
          ibit = bp_unpack_value (&bp, 8);
          fbit = bp_unpack_value (&bp, 8);
          break;
        case MODE_FLOAT:
        case MODE_DECIMAL_FLOAT:
          real_fmt_name = bp_unpack_indexed_string (data_in, &bp,
                                                    &real_fmt_len);
          break;
        default:
          break;
        }
      /* First search just the GET_CLASS_NARROWEST_MODE to wider modes,
         if not found, fallback to all modes.  */
      int pass;
      for (pass = 0; pass < 2; pass++)
        for (machine_mode mr = pass ? VOIDmode
                                    : GET_CLASS_NARROWEST_MODE (mclass);
             pass ? mr < MAX_MACHINE_MODE : mr != VOIDmode;
             pass ? mr = (machine_mode) (mr + 1)
                  : mr = GET_MODE_WIDER_MODE (mr).else_void ())
          if (GET_MODE_CLASS (mr) != mclass
              || maybe_ne (GET_MODE_SIZE (mr), size)
              || maybe_ne (GET_MODE_PRECISION (mr), prec)
              || (inner == m
                  ? GET_MODE_INNER (mr) != mr
                  : GET_MODE_INNER (mr) != table[(int) inner])
              || GET_MODE_IBIT (mr) != ibit
              || GET_MODE_FBIT (mr) != fbit
              || maybe_ne (GET_MODE_NUNITS (mr), nunits))
            continue;
          else if ((mclass == MODE_FLOAT || mclass == MODE_DECIMAL_FLOAT)
                   && strcmp (REAL_MODE_FORMAT (mr)->name, real_fmt_name) != 0)
            continue;
          else
            {
              table[m] = mr;
              pass = 2;
              break;
            }
      unsigned int mname_len;
      const char *mname = bp_unpack_indexed_string (data_in, &bp, &mname_len);
      if (pass == 2)
        {
          switch (mclass)
            {
            case MODE_VECTOR_BOOL:
            case MODE_VECTOR_INT:
            case MODE_VECTOR_FLOAT:
            case MODE_VECTOR_FRACT:
            case MODE_VECTOR_UFRACT:
            case MODE_VECTOR_ACCUM:
            case MODE_VECTOR_UACCUM:
              /* For unsupported vector modes just use BLKmode,
                 if the scalar mode is supported.  */
              if (table[(int) inner] != VOIDmode)
                {
                  table[m] = BLKmode;
                  break;
                }
              /* FALLTHRU */
            default:
              /* This is only used for offloading-target compilations and
                 is a user-facing error.  Give a better error message for
                 the common modes; see also mode-classes.def.   */
              if (mclass == MODE_FLOAT)
                fatal_error (UNKNOWN_LOCATION,
                             "%s - %u-bit-precision floating-point numbers "
                             "unsupported (mode %qs)", TARGET_MACHINE,
                             prec.to_constant (), mname);
              else if (mclass == MODE_DECIMAL_FLOAT)
                fatal_error (UNKNOWN_LOCATION,
                             "%s - %u-bit-precision decimal floating-point "
                             "numbers unsupported (mode %qs)", TARGET_MACHINE,
                             prec.to_constant (), mname);
              else if (mclass == MODE_COMPLEX_FLOAT)
                fatal_error (UNKNOWN_LOCATION,
                             "%s - %u-bit-precision complex floating-point "
                             "numbers unsupported (mode %qs)", TARGET_MACHINE,
                             prec.to_constant (), mname);
              else if (mclass == MODE_INT)
                fatal_error (UNKNOWN_LOCATION,
                             "%s - %u-bit integer numbers unsupported (mode "
                             "%qs)", TARGET_MACHINE, prec.to_constant (), mname);
              else
                fatal_error (UNKNOWN_LOCATION, "%s - unsupported mode %qs",
                             TARGET_MACHINE, mname);
              break;
            }
        }
    }
  lto_data_in_delete (data_in);

  lto_free_section_data (file_data, LTO_section_mode_table, NULL, data, len);
}


/* Initialization for the LTO reader.  */

void
lto_reader_init (void)
{
  lto_streamer_init ();
  file_name_hash_table
    = new hash_table<string_slot_hasher> (37);
  string_slot_allocator = new object_allocator <struct string_slot>
                                ("line map file name hash");
  gcc_obstack_init (&file_name_obstack);
}

/* Free hash table used to stream in location file names.  */

void
lto_free_file_name_hash (void)
{
  delete file_name_hash_table;
  file_name_hash_table = NULL;
  delete string_slot_allocator;
  string_slot_allocator = NULL;
  /* file_name_obstack must stay allocated since it is referred to by
     line map table.  */
}


/* Create a new data_in object for FILE_DATA. STRINGS is the string
   table to use with LEN strings.  RESOLUTIONS is the vector of linker
   resolutions (NULL if not using a linker plugin).  */

class data_in *
lto_data_in_create (struct lto_file_decl_data *file_data, const char *strings,
                    unsigned len,
                    vec<ld_plugin_symbol_resolution_t> resolutions)
{
  class data_in *data_in = new (class data_in);
  data_in->file_data = file_data;
  data_in->strings = strings;
  data_in->strings_len = len;
  data_in->globals_resolution = resolutions;
  data_in->reader_cache = streamer_tree_cache_create (false, false, true);
  return data_in;
}


/* Remove DATA_IN.  */

void
lto_data_in_delete (class data_in *data_in)
{
  data_in->globals_resolution.release ();
  streamer_tree_cache_delete (data_in->reader_cache);
  delete data_in;
}