rebase

[gcc.git] / gcc / tree-streamer-in.c

/* Routines for reading trees from a file stream.

   Copyright 2011 Free Software Foundation, Inc.
   Contributed 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 "diagnostic.h"
#include "tree.h"
#include "tree-flow.h"
#include "tree-streamer.h"
#include "data-streamer.h"
#include "streamer-hooks.h"
#include "lto-streamer.h"

/* Read a STRING_CST from the string table in DATA_IN using input
   block IB.  */

tree
input_string_cst (struct data_in *data_in, struct lto_input_block *ib)
{
  unsigned int len;
  const char * ptr;

  ptr = input_string_internal (data_in, ib, &len);
  if (!ptr)
    return NULL;
  return build_string (len, ptr);
}


/* Read an IDENTIFIER from the string table in DATA_IN using input
   block IB.  */

static tree
input_identifier (struct data_in *data_in, struct lto_input_block *ib)
{
  unsigned int len;
  const char *ptr;

  ptr = input_string_internal (data_in, ib, &len);
  if (!ptr)
    return NULL;
  return get_identifier_with_length (ptr, len);
}


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

static tree
lto_input_chain (struct lto_input_block *ib, struct data_in *data_in)
{
  int i, count;
  tree first, prev, curr;

  first = prev = NULL_TREE;
  count = lto_input_sleb128 (ib);
  for (i = 0; i < count; i++)
    {
      curr = lto_input_tree (ib, data_in);
      if (prev)
        TREE_CHAIN (prev) = curr;
      else
        first = curr;

      TREE_CHAIN (curr) = NULL_TREE;
      prev = curr;
    }

  return first;
}


/* Unpack all the non-pointer fields of the TS_BASE structure of
   expression EXPR from bitpack BP.  */

static void
unpack_ts_base_value_fields (struct bitpack_d *bp, tree expr)
{
  /* Note that the code for EXPR has already been unpacked to create EXPR in
     lto_materialize_tree.  */
  if (!TYPE_P (expr))
    {
      TREE_SIDE_EFFECTS (expr) = (unsigned) bp_unpack_value (bp, 1);
      TREE_CONSTANT (expr) = (unsigned) bp_unpack_value (bp, 1);
      TREE_READONLY (expr) = (unsigned) bp_unpack_value (bp, 1);

      /* TREE_PUBLIC is used on types to indicate that the type
         has a TYPE_CACHED_VALUES vector.  This is not streamed out,
         so we skip it here.  */
      TREE_PUBLIC (expr) = (unsigned) bp_unpack_value (bp, 1);
    }
  else
    bp_unpack_value (bp, 4);
  TREE_ADDRESSABLE (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_THIS_VOLATILE (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (DECL_P (expr))
    DECL_UNSIGNED (expr) = (unsigned) bp_unpack_value (bp, 1);
  else if (TYPE_P (expr))
    TYPE_UNSIGNED (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    bp_unpack_value (bp, 1);
  TREE_ASM_WRITTEN (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (TYPE_P (expr))
    TYPE_ARTIFICIAL (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    TREE_NO_WARNING (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_USED (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_NOTHROW (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_STATIC (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_PRIVATE (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_PROTECTED (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_DEPRECATED (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (TYPE_P (expr))
    TYPE_SATURATING (expr) = (unsigned) bp_unpack_value (bp, 1);
  else if (TREE_CODE (expr) == SSA_NAME)
    SSA_NAME_IS_DEFAULT_DEF (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    bp_unpack_value (bp, 1);
}


/* Unpack all the non-pointer fields of the TS_REAL_CST structure of
   expression EXPR from bitpack BP.  */

static void
unpack_ts_real_cst_value_fields (struct bitpack_d *bp, tree expr)
{
  unsigned i;
  REAL_VALUE_TYPE r;
  REAL_VALUE_TYPE *rp;

  r.cl = (unsigned) bp_unpack_value (bp, 2);
  r.decimal = (unsigned) bp_unpack_value (bp, 1);
  r.sign = (unsigned) bp_unpack_value (bp, 1);
  r.signalling = (unsigned) bp_unpack_value (bp, 1);
  r.canonical = (unsigned) bp_unpack_value (bp, 1);
  r.uexp = (unsigned) bp_unpack_value (bp, EXP_BITS);
  for (i = 0; i < SIGSZ; i++)
    r.sig[i] = (unsigned long) bp_unpack_value (bp, HOST_BITS_PER_LONG);

  rp = ggc_alloc_real_value ();
  memcpy (rp, &r, sizeof (REAL_VALUE_TYPE));
  TREE_REAL_CST_PTR (expr) = rp;
}


/* Unpack all the non-pointer fields of the TS_FIXED_CST structure of
   expression EXPR from bitpack BP.  */

static void
unpack_ts_fixed_cst_value_fields (struct bitpack_d *bp, tree expr)
{
  struct fixed_value fv;

  fv.mode = bp_unpack_enum (bp, machine_mode, MAX_MACHINE_MODE);
  fv.data.low = bp_unpack_var_len_int (bp);
  fv.data.high = bp_unpack_var_len_int (bp);
  TREE_FIXED_CST (expr) = fv;
}


/* Unpack all the non-pointer fields of the TS_DECL_COMMON structure
   of expression EXPR from bitpack BP.  */

static void
unpack_ts_decl_common_value_fields (struct bitpack_d *bp, tree expr)
{
  DECL_MODE (expr) = bp_unpack_enum (bp, machine_mode, MAX_MACHINE_MODE);
  DECL_NONLOCAL (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_VIRTUAL_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_IGNORED_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_ABSTRACT (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_ARTIFICIAL (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_USER_ALIGN (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_PRESERVE_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_DEBUG_EXPR_IS_FROM (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_EXTERNAL (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_GIMPLE_REG_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_ALIGN (expr) = (unsigned) bp_unpack_var_len_unsigned (bp);

  if (TREE_CODE (expr) == LABEL_DECL)
    {
      DECL_ERROR_ISSUED (expr) = (unsigned) bp_unpack_value (bp, 1);
      EH_LANDING_PAD_NR (expr) = (int) bp_unpack_var_len_unsigned (bp);

      /* Always assume an initial value of -1 for LABEL_DECL_UID to
         force gimple_set_bb to recreate label_to_block_map.  */
      LABEL_DECL_UID (expr) = -1;
    }

  if (TREE_CODE (expr) == FIELD_DECL)
    {
      DECL_PACKED (expr) = (unsigned) bp_unpack_value (bp, 1);
      DECL_NONADDRESSABLE_P (expr) = (unsigned) bp_unpack_value (bp, 1);
      expr->decl_common.off_align = bp_unpack_value (bp, 8);
    }

  if (TREE_CODE (expr) == RESULT_DECL
      || TREE_CODE (expr) == PARM_DECL
      || TREE_CODE (expr) == VAR_DECL)
    {
      DECL_BY_REFERENCE (expr) = (unsigned) bp_unpack_value (bp, 1);
      if (TREE_CODE (expr) == VAR_DECL
          || TREE_CODE (expr) == PARM_DECL)
        DECL_HAS_VALUE_EXPR_P (expr) = (unsigned) bp_unpack_value (bp, 1);
      DECL_RESTRICTED_P (expr) = (unsigned) bp_unpack_value (bp, 1);
    }
}


/* Unpack all the non-pointer fields of the TS_DECL_WRTL structure
   of expression EXPR from bitpack BP.  */

static void
unpack_ts_decl_wrtl_value_fields (struct bitpack_d *bp, tree expr)
{
  DECL_REGISTER (expr) = (unsigned) bp_unpack_value (bp, 1);
}


/* Unpack all the non-pointer fields of the TS_DECL_WITH_VIS structure
   of expression EXPR from bitpack BP.  */

static void
unpack_ts_decl_with_vis_value_fields (struct bitpack_d *bp, tree expr)
{
  DECL_DEFER_OUTPUT (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_COMMON (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_DLLIMPORT_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_WEAK (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_SEEN_IN_BIND_EXPR_P (expr) = (unsigned) bp_unpack_value (bp,  1);
  DECL_COMDAT (expr) = (unsigned) bp_unpack_value (bp,  1);
  DECL_VISIBILITY (expr) = (enum symbol_visibility) bp_unpack_value (bp,  2);
  DECL_VISIBILITY_SPECIFIED (expr) = (unsigned) bp_unpack_value (bp,  1);

  if (TREE_CODE (expr) == VAR_DECL)
    {
      DECL_HARD_REGISTER (expr) = (unsigned) bp_unpack_value (bp, 1);
      DECL_IN_TEXT_SECTION (expr) = (unsigned) bp_unpack_value (bp, 1);
      DECL_IN_CONSTANT_POOL (expr) = (unsigned) bp_unpack_value (bp, 1);
      DECL_TLS_MODEL (expr) = (enum tls_model) bp_unpack_value (bp,  3);
    }

  if (VAR_OR_FUNCTION_DECL_P (expr))
    {
      priority_type p;
      p = (priority_type) bp_unpack_var_len_unsigned (bp);
      SET_DECL_INIT_PRIORITY (expr, p);
    }
}


/* Unpack all the non-pointer fields of the TS_FUNCTION_DECL structure
   of expression EXPR from bitpack BP.  */

static void
unpack_ts_function_decl_value_fields (struct bitpack_d *bp, tree expr)
{
  DECL_BUILT_IN_CLASS (expr) = bp_unpack_enum (bp, built_in_class,
                                               BUILT_IN_LAST);
  DECL_STATIC_CONSTRUCTOR (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_STATIC_DESTRUCTOR (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_UNINLINABLE (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_POSSIBLY_INLINED (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_IS_NOVOPS (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_IS_RETURNS_TWICE (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_IS_MALLOC (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_IS_OPERATOR_NEW (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_DECLARED_INLINE_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_STATIC_CHAIN (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_NO_INLINE_WARNING_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (expr)
                        = (unsigned) bp_unpack_value (bp, 1);
  DECL_NO_LIMIT_STACK (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_DISREGARD_INLINE_LIMITS (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_PURE_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  DECL_LOOPING_CONST_OR_PURE_P (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (DECL_BUILT_IN_CLASS (expr) != NOT_BUILT_IN)
    {
      DECL_FUNCTION_CODE (expr) = (enum built_in_function) bp_unpack_value (bp,
                                                                            11);
      if (DECL_BUILT_IN_CLASS (expr) == BUILT_IN_NORMAL
          && DECL_FUNCTION_CODE (expr) >= END_BUILTINS)
        fatal_error ("machine independent builtin code out of range");
      else if (DECL_BUILT_IN_CLASS (expr) == BUILT_IN_MD)
        {
          tree result = targetm.builtin_decl (DECL_FUNCTION_CODE (expr), true);
          if (!result || result == error_mark_node)
            fatal_error ("target specific builtin not available");
        }
    }
  if (DECL_STATIC_DESTRUCTOR (expr))
    {
      priority_type p;
      p = (priority_type) bp_unpack_var_len_unsigned (bp);
      SET_DECL_FINI_PRIORITY (expr, p);
    }
}


/* Unpack all the non-pointer fields of the TS_TYPE_COMMON structure
   of expression EXPR from bitpack BP.  */

static void
unpack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr)
{
  enum machine_mode mode;

  mode = bp_unpack_enum (bp, machine_mode, MAX_MACHINE_MODE);
  SET_TYPE_MODE (expr, mode);
  TYPE_STRING_FLAG (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_NO_FORCE_BLK (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_NEEDS_CONSTRUCTING (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (RECORD_OR_UNION_TYPE_P (expr))
    TYPE_TRANSPARENT_AGGR (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_PACKED (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_RESTRICT (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_CONTAINS_PLACEHOLDER_INTERNAL (expr)
        = (unsigned) bp_unpack_value (bp, 2);
  TYPE_USER_ALIGN (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_READONLY (expr) = (unsigned) bp_unpack_value (bp, 1);
  TYPE_PRECISION (expr) = bp_unpack_var_len_unsigned (bp);
  TYPE_ALIGN (expr) = bp_unpack_var_len_unsigned (bp);
  TYPE_ALIAS_SET (expr) = bp_unpack_var_len_int (bp);
}


/* Unpack all the non-pointer fields of the TS_BLOCK structure
   of expression EXPR from bitpack BP.  */

static void
unpack_ts_block_value_fields (struct bitpack_d *bp, tree expr)
{
  BLOCK_ABSTRACT (expr) = (unsigned) bp_unpack_value (bp, 1);
  /* BLOCK_NUMBER is recomputed.  */
}

/* Unpack all the non-pointer fields of the TS_TRANSLATION_UNIT_DECL
   structure of expression EXPR from bitpack BP.  */

static void
unpack_ts_translation_unit_decl_value_fields (struct bitpack_d *bp ATTRIBUTE_UNUSED, tree expr ATTRIBUTE_UNUSED)
{
}

/* Unpack all the non-pointer fields in EXPR into a bit pack.  */

static void
unpack_value_fields (struct bitpack_d *bp, tree expr)
{
  enum tree_code code;

  code = TREE_CODE (expr);

  /* Note that all these functions are highly sensitive to changes in
     the types and sizes of each of the fields being packed.  */
  unpack_ts_base_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_REAL_CST))
    unpack_ts_real_cst_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_FIXED_CST))
    unpack_ts_fixed_cst_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_COMMON))
    unpack_ts_decl_common_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_WRTL))
    unpack_ts_decl_wrtl_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_WITH_VIS))
    unpack_ts_decl_with_vis_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_FUNCTION_DECL))
    unpack_ts_function_decl_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TYPE_COMMON))
    unpack_ts_type_common_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_BLOCK))
    unpack_ts_block_value_fields (bp, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TRANSLATION_UNIT_DECL))
    unpack_ts_translation_unit_decl_value_fields (bp, expr);

  if (streamer_hooks.unpack_value_fields)
    streamer_hooks.unpack_value_fields (bp, expr);
}


/* Materialize a new tree from input block IB using descriptors in
   DATA_IN.  The code for the new tree should match TAG.  Store in
   *IX_P the index into the reader cache where the new tree is stored.  */

static tree
lto_materialize_tree (struct lto_input_block *ib, struct data_in *data_in,
                      enum LTO_tags tag)
{
  struct bitpack_d bp;
  enum tree_code code;
  tree result;
#ifdef LTO_STREAMER_DEBUG
  HOST_WIDEST_INT orig_address_in_writer;
#endif

  result = NULL_TREE;

#ifdef LTO_STREAMER_DEBUG
  /* Read the word representing the memory address for the tree
     as it was written by the writer.  This is useful when
     debugging differences between the writer and reader.  */
  orig_address_in_writer = lto_input_sleb128 (ib);
  gcc_assert ((intptr_t) orig_address_in_writer == orig_address_in_writer);
#endif

  code = lto_tag_to_tree_code (tag);

  /* We should never see an SSA_NAME tree.  Only the version numbers of
     SSA names are ever written out.  See input_ssa_names.  */
  gcc_assert (code != SSA_NAME);

  /* Instantiate a new tree using the header data.  */
  if (CODE_CONTAINS_STRUCT (code, TS_STRING))
    result = input_string_cst (data_in, ib);
  else if (CODE_CONTAINS_STRUCT (code, TS_IDENTIFIER))
    result = input_identifier (data_in, ib);
  else if (CODE_CONTAINS_STRUCT (code, TS_VEC))
    {
      HOST_WIDE_INT len = lto_input_sleb128 (ib);
      result = make_tree_vec (len);
    }
  else if (CODE_CONTAINS_STRUCT (code, TS_BINFO))
    {
      unsigned HOST_WIDE_INT len = lto_input_uleb128 (ib);
      result = make_tree_binfo (len);
    }
  else
    {
      /* For all other nodes, see if the streamer knows how to allocate
         it.  */
      if (streamer_hooks.alloc_tree)
        result = streamer_hooks.alloc_tree (code, ib, data_in);

      /* If the hook did not handle it, materialize the tree with a raw
         make_node call.  */
      if (result == NULL_TREE)
        result = make_node (code);
    }

#ifdef LTO_STREAMER_DEBUG
  /* Store the original address of the tree as seen by the writer
     in RESULT's aux field.  This is useful when debugging streaming
     problems.  This way, a debugging session can be started on
     both writer and reader with a breakpoint using this address
     value in both.  */
  lto_orig_address_map (result, (intptr_t) orig_address_in_writer);
#endif

  /* Read the bitpack of non-pointer values from IB.  */
  bp = lto_input_bitpack (ib);

  /* The first word in BP contains the code of the tree that we
     are about to read.  */
  code = (enum tree_code) bp_unpack_value (&bp, 16);
  lto_tag_check (lto_tree_code_to_tag (code), tag);

  /* Unpack all the value fields from BP.  */
  unpack_value_fields (&bp, result);

  /* 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 lto_input_tree.  */
  lto_streamer_cache_append (data_in->reader_cache, result);

  return result;
}


/* Read all pointer fields in the TS_COMMON structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */


static void
lto_input_ts_common_tree_pointers (struct lto_input_block *ib,
                                   struct data_in *data_in, tree expr)
{
  if (TREE_CODE (expr) != IDENTIFIER_NODE)
    TREE_TYPE (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_VECTOR structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_vector_tree_pointers (struct lto_input_block *ib,
                                   struct data_in *data_in, tree expr)
{
  TREE_VECTOR_CST_ELTS (expr) = lto_input_chain (ib, data_in);
}


/* Read all pointer fields in the TS_COMPLEX structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_complex_tree_pointers (struct lto_input_block *ib,
                                    struct data_in *data_in, tree expr)
{
  TREE_REALPART (expr) = lto_input_tree (ib, data_in);
  TREE_IMAGPART (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_DECL_MINIMAL structure of EXPR
   from input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_decl_minimal_tree_pointers (struct lto_input_block *ib,
                                         struct data_in *data_in, tree expr)
{
  DECL_NAME (expr) = lto_input_tree (ib, data_in);
  DECL_CONTEXT (expr) = lto_input_tree (ib, data_in);
  DECL_SOURCE_LOCATION (expr) = lto_input_location (ib, data_in);
}


/* Read all pointer fields in the TS_DECL_COMMON structure of EXPR from
   input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_decl_common_tree_pointers (struct lto_input_block *ib,
                                        struct data_in *data_in, tree expr)
{
  DECL_SIZE (expr) = lto_input_tree (ib, data_in);
  DECL_SIZE_UNIT (expr) = lto_input_tree (ib, data_in);
  DECL_ATTRIBUTES (expr) = lto_input_tree (ib, data_in);

  /* Do not stream DECL_ABSTRACT_ORIGIN.  We cannot handle debug information
     for early inlining so drop it on the floor instead of ICEing in
     dwarf2out.c.  */

  if (TREE_CODE (expr) == PARM_DECL)
    TREE_CHAIN (expr) = lto_input_chain (ib, data_in);

  if ((TREE_CODE (expr) == VAR_DECL
       || TREE_CODE (expr) == PARM_DECL)
      && DECL_HAS_VALUE_EXPR_P (expr))
    SET_DECL_VALUE_EXPR (expr, lto_input_tree (ib, data_in));

  if (TREE_CODE (expr) == VAR_DECL)
    {
      tree dexpr = lto_input_tree (ib, data_in);
      if (dexpr)
        SET_DECL_DEBUG_EXPR (expr, dexpr);
    }
}


/* Read all pointer fields in the TS_DECL_NON_COMMON structure of
   EXPR from input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_decl_non_common_tree_pointers (struct lto_input_block *ib,
                                            struct data_in *data_in, tree expr)
{
  if (TREE_CODE (expr) == FUNCTION_DECL)
    {
      DECL_ARGUMENTS (expr) = lto_input_tree (ib, data_in);
      DECL_RESULT (expr) = lto_input_tree (ib, data_in);
    }
  DECL_VINDEX (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_DECL_WITH_VIS structure of EXPR
   from input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_decl_with_vis_tree_pointers (struct lto_input_block *ib,
                                          struct data_in *data_in, tree expr)
{
  tree id;

  id = lto_input_tree (ib, data_in);
  if (id)
    {
      gcc_assert (TREE_CODE (id) == IDENTIFIER_NODE);
      SET_DECL_ASSEMBLER_NAME (expr, id);
    }

  DECL_SECTION_NAME (expr) = lto_input_tree (ib, data_in);
  DECL_COMDAT_GROUP (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_FIELD_DECL structure of EXPR from
   input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_field_decl_tree_pointers (struct lto_input_block *ib,
                                       struct data_in *data_in, tree expr)
{
  DECL_FIELD_OFFSET (expr) = lto_input_tree (ib, data_in);
  DECL_BIT_FIELD_TYPE (expr) = lto_input_tree (ib, data_in);
  DECL_QUALIFIER (expr) = lto_input_tree (ib, data_in);
  DECL_FIELD_BIT_OFFSET (expr) = lto_input_tree (ib, data_in);
  DECL_FCONTEXT (expr) = lto_input_tree (ib, data_in);
  TREE_CHAIN (expr) = lto_input_chain (ib, data_in);
}


/* Read all pointer fields in the TS_FUNCTION_DECL structure of EXPR
   from input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_function_decl_tree_pointers (struct lto_input_block *ib,
                                          struct data_in *data_in, tree expr)
{
  /* DECL_STRUCT_FUNCTION is handled by lto_input_function.  FIXME lto,
     maybe it should be handled here?  */
  DECL_FUNCTION_PERSONALITY (expr) = lto_input_tree (ib, data_in);
  DECL_FUNCTION_SPECIFIC_TARGET (expr) = lto_input_tree (ib, data_in);
  DECL_FUNCTION_SPECIFIC_OPTIMIZATION (expr) = lto_input_tree (ib, data_in);

  /* If the file contains a function with an EH personality set,
     then it was compiled with -fexceptions.  In that case, initialize
     the backend EH machinery.  */
  if (DECL_FUNCTION_PERSONALITY (expr))
    lto_init_eh ();
}


/* Read all pointer fields in the TS_TYPE_COMMON structure of EXPR from
   input block IB.  DATA_IN contains tables and descriptors for the file
   being read.  */

static void
lto_input_ts_type_common_tree_pointers (struct lto_input_block *ib,
                                        struct data_in *data_in, tree expr)
{
  TYPE_SIZE (expr) = lto_input_tree (ib, data_in);
  TYPE_SIZE_UNIT (expr) = lto_input_tree (ib, data_in);
  TYPE_ATTRIBUTES (expr) = lto_input_tree (ib, data_in);
  TYPE_NAME (expr) = lto_input_tree (ib, data_in);
  /* Do not stream TYPE_POINTER_TO or TYPE_REFERENCE_TO.  They will be
     reconstructed during fixup.  */
  /* Do not stream TYPE_NEXT_VARIANT, we reconstruct the variant lists
     during fixup.  */
  TYPE_MAIN_VARIANT (expr) = lto_input_tree (ib, data_in);
  TYPE_CONTEXT (expr) = lto_input_tree (ib, data_in);
  /* TYPE_CANONICAL gets re-computed during type merging.  */
  TYPE_CANONICAL (expr) = NULL_TREE;
  TYPE_STUB_DECL (expr) = lto_input_tree (ib, data_in);
}

/* Read all pointer fields in the TS_TYPE_NON_COMMON structure of EXPR
   from input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_type_non_common_tree_pointers (struct lto_input_block *ib,
                                            struct data_in *data_in,
                                            tree expr)
{
  if (TREE_CODE (expr) == ENUMERAL_TYPE)
    TYPE_VALUES (expr) = lto_input_tree (ib, data_in);
  else if (TREE_CODE (expr) == ARRAY_TYPE)
    TYPE_DOMAIN (expr) = lto_input_tree (ib, data_in);
  else if (RECORD_OR_UNION_TYPE_P (expr))
    TYPE_FIELDS (expr) = lto_input_tree (ib, data_in);
  else if (TREE_CODE (expr) == FUNCTION_TYPE
           || TREE_CODE (expr) == METHOD_TYPE)
    TYPE_ARG_TYPES (expr) = lto_input_tree (ib, data_in);

  if (!POINTER_TYPE_P (expr))
    TYPE_MINVAL (expr) = lto_input_tree (ib, data_in);
  TYPE_MAXVAL (expr) = lto_input_tree (ib, data_in);
  if (RECORD_OR_UNION_TYPE_P (expr))
    TYPE_BINFO (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_LIST structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_list_tree_pointers (struct lto_input_block *ib,
                                 struct data_in *data_in, tree expr)
{
  TREE_PURPOSE (expr) = lto_input_tree (ib, data_in);
  TREE_VALUE (expr) = lto_input_tree (ib, data_in);
  TREE_CHAIN (expr) = lto_input_chain (ib, data_in);
}


/* Read all pointer fields in the TS_VEC structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_vec_tree_pointers (struct lto_input_block *ib,
                                struct data_in *data_in, tree expr)
{
  int i;

  /* Note that TREE_VEC_LENGTH was read by lto_materialize_tree to
     instantiate EXPR.  */
  for (i = 0; i < TREE_VEC_LENGTH (expr); i++)
    TREE_VEC_ELT (expr, i) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_EXP structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */


static void
lto_input_ts_exp_tree_pointers (struct lto_input_block *ib,
                                struct data_in *data_in, tree expr)
{
  int i, length;
  location_t loc;

  length = lto_input_sleb128 (ib);
  gcc_assert (length == TREE_OPERAND_LENGTH (expr));

  for (i = 0; i < length; i++)
    TREE_OPERAND (expr, i) = lto_input_tree (ib, data_in);

  loc = lto_input_location (ib, data_in);
  SET_EXPR_LOCATION (expr, loc);
  TREE_BLOCK (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_BLOCK structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_block_tree_pointers (struct lto_input_block *ib,
                                  struct data_in *data_in, tree expr)
{
  /* Do not stream BLOCK_SOURCE_LOCATION.  We cannot handle debug information
     for early inlining so drop it on the floor instead of ICEing in
     dwarf2out.c.  */
  BLOCK_VARS (expr) = lto_input_chain (ib, data_in);

  /* Do not stream BLOCK_NONLOCALIZED_VARS.  We cannot handle debug information
     for early inlining so drop it on the floor instead of ICEing in
     dwarf2out.c.  */

  BLOCK_SUPERCONTEXT (expr) = lto_input_tree (ib, data_in);

  /* Do not stream BLOCK_ABSTRACT_ORIGIN.  We cannot handle debug information
     for early inlining so drop it on the floor instead of ICEing in
     dwarf2out.c.  */
  BLOCK_FRAGMENT_ORIGIN (expr) = lto_input_tree (ib, data_in);
  BLOCK_FRAGMENT_CHAIN (expr) = lto_input_tree (ib, data_in);

  /* We re-compute BLOCK_SUBBLOCKS of our parent here instead
     of streaming it.  For non-BLOCK BLOCK_SUPERCONTEXTs we still
     stream the child relationship explicitly.  */
  if (BLOCK_SUPERCONTEXT (expr)
      && TREE_CODE (BLOCK_SUPERCONTEXT (expr)) == BLOCK)
    {
      BLOCK_CHAIN (expr) = BLOCK_SUBBLOCKS (BLOCK_SUPERCONTEXT (expr));
      BLOCK_SUBBLOCKS (BLOCK_SUPERCONTEXT (expr)) = expr;
    }

  /* The global block is rooted at the TU decl.  Hook it here to
     avoid the need to stream in this block during WPA time.  */
  else if (BLOCK_SUPERCONTEXT (expr)
           && TREE_CODE (BLOCK_SUPERCONTEXT (expr)) == TRANSLATION_UNIT_DECL)
    DECL_INITIAL (BLOCK_SUPERCONTEXT (expr)) = expr;

  /* The function-level block is connected at the time we read in
     function bodies for the same reason.  */
}


/* Read all pointer fields in the TS_BINFO structure of EXPR from input
   block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_binfo_tree_pointers (struct lto_input_block *ib,
                                  struct data_in *data_in, tree expr)
{
  unsigned i, len;
  tree t;

  /* Note that the number of slots in EXPR was read in
     lto_materialize_tree when instantiating EXPR.  However, the
     vector is empty so we cannot rely on VEC_length to know how many
     elements to read.  So, this list is emitted as a 0-terminated
     list on the writer side.  */
  do
    {
      t = lto_input_tree (ib, data_in);
      if (t)
        VEC_quick_push (tree, BINFO_BASE_BINFOS (expr), t);
    }
  while (t);

  BINFO_OFFSET (expr) = lto_input_tree (ib, data_in);
  BINFO_VTABLE (expr) = lto_input_tree (ib, data_in);
  BINFO_VIRTUALS (expr) = lto_input_tree (ib, data_in);
  BINFO_VPTR_FIELD (expr) = lto_input_tree (ib, data_in);

  len = lto_input_uleb128 (ib);
  if (len > 0)
    {
      VEC_reserve_exact (tree, gc, BINFO_BASE_ACCESSES (expr), len);
      for (i = 0; i < len; i++)
        {
          tree a = lto_input_tree (ib, data_in);
          VEC_quick_push (tree, BINFO_BASE_ACCESSES (expr), a);
        }
    }

  BINFO_INHERITANCE_CHAIN (expr) = lto_input_tree (ib, data_in);
  BINFO_SUBVTT_INDEX (expr) = lto_input_tree (ib, data_in);
  BINFO_VPTR_INDEX (expr) = lto_input_tree (ib, data_in);
}


/* Read all pointer fields in the TS_CONSTRUCTOR structure of EXPR from
   input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_ts_constructor_tree_pointers (struct lto_input_block *ib,
                                        struct data_in *data_in, tree expr)
{
  unsigned i, len;

  len = lto_input_uleb128 (ib);
  for (i = 0; i < len; i++)
    {
      tree index, value;

      index = lto_input_tree (ib, data_in);
      value = lto_input_tree (ib, data_in);
      CONSTRUCTOR_APPEND_ELT (CONSTRUCTOR_ELTS (expr), index, value);
    }
}


/* Input a TS_TARGET_OPTION tree from IB into EXPR.  */

static void
lto_input_ts_target_option (struct lto_input_block *ib, tree expr)
{
  unsigned i, len;
  struct bitpack_d bp;
  struct cl_target_option *t = TREE_TARGET_OPTION (expr);

  bp = lto_input_bitpack (ib);
  len = sizeof (struct cl_target_option);
  for (i = 0; i < len; i++)
    ((unsigned char *)t)[i] = bp_unpack_value (&bp, 8);
  if (bp_unpack_value (&bp, 32) != 0x12345678)
    fatal_error ("cl_target_option size mismatch in LTO reader and writer");
}

/* Input a TS_TRANSLATION_UNIT_DECL tree from IB and DATA_IN into EXPR.  */

static void
lto_input_ts_translation_unit_decl_tree_pointers (struct lto_input_block *ib,
                                                  struct data_in *data_in,
                                                  tree expr)
{
  TRANSLATION_UNIT_LANGUAGE (expr) = xstrdup (lto_input_string (data_in, ib));
  VEC_safe_push (tree, gc, all_translation_units, expr);
}

/* Helper for lto_input_tree.  Read all pointer fields in EXPR from
   input block IB.  DATA_IN contains tables and descriptors for the
   file being read.  */

static void
lto_input_tree_pointers (struct lto_input_block *ib, struct data_in *data_in,
                         tree expr)
{
  enum tree_code code;

  code = TREE_CODE (expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TYPED))
    lto_input_ts_common_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_VECTOR))
    lto_input_ts_vector_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_COMPLEX))
    lto_input_ts_complex_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_MINIMAL))
    lto_input_ts_decl_minimal_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_COMMON))
    lto_input_ts_decl_common_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_NON_COMMON))
    lto_input_ts_decl_non_common_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_DECL_WITH_VIS))
    lto_input_ts_decl_with_vis_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_FIELD_DECL))
    lto_input_ts_field_decl_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_FUNCTION_DECL))
    lto_input_ts_function_decl_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TYPE_COMMON))
    lto_input_ts_type_common_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TYPE_NON_COMMON))
    lto_input_ts_type_non_common_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_LIST))
    lto_input_ts_list_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_VEC))
    lto_input_ts_vec_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_EXP))
    lto_input_ts_exp_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_BLOCK))
    lto_input_ts_block_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_BINFO))
    lto_input_ts_binfo_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_CONSTRUCTOR))
    lto_input_ts_constructor_tree_pointers (ib, data_in, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TARGET_OPTION))
    lto_input_ts_target_option (ib, expr);

  if (CODE_CONTAINS_STRUCT (code, TS_TRANSLATION_UNIT_DECL))
    lto_input_ts_translation_unit_decl_tree_pointers (ib, data_in, expr);
}


/* 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 (struct lto_input_block *ib, struct data_in *data_in,
               enum LTO_tags tag)
{
  tree result;

  result = lto_materialize_tree (ib, data_in, tag);

  /* Read all the pointer fields in RESULT.  */
  lto_input_tree_pointers (ib, data_in, result);

  /* Call back into the streaming module to read anything else it
     may need.  */
  if (streamer_hooks.read_tree)
    streamer_hooks.read_tree (ib, data_in, result);

  /* We should never try to instantiate an MD or NORMAL builtin here.  */
  if (TREE_CODE (result) == FUNCTION_DECL)
    gcc_assert (!lto_stream_as_builtin_p (result));

  /* end_marker = */ lto_input_1_unsigned (ib);

#ifdef LTO_STREAMER_DEBUG
  /* Remove the mapping to RESULT's original address set by
     lto_materialize_tree.  */
  lto_orig_address_remove (result);
#endif

  return result;
}


/* Read and INTEGER_CST node from input block IB using the per-file
   context in DATA_IN.  */

static tree
lto_input_integer_cst (struct lto_input_block *ib, struct data_in *data_in)
{
  tree result, type;
  HOST_WIDE_INT low, high;
  bool overflow_p;

  type = lto_input_tree (ib, data_in);
  overflow_p = (lto_input_1_unsigned (ib) != 0);
  low = lto_input_uleb128 (ib);
  high = lto_input_uleb128 (ib);
  result = build_int_cst_wide (type, low, high);

  /* If the original constant had overflown, build a replica of RESULT to
     avoid modifying the shared constant returned by build_int_cst_wide.  */
  if (overflow_p)
    {
      result = copy_node (result);
      TREE_OVERFLOW (result) = 1;
    }

  return result;
}


/* Read an index IX from input block IB and return the tree node at
   DATA_IN->FILE_DATA->GLOBALS_INDEX[IX].  */

static tree
lto_get_pickled_tree (struct lto_input_block *ib, struct data_in *data_in)
{
  unsigned HOST_WIDE_INT ix;
  tree result;
  enum LTO_tags expected_tag;

  ix = lto_input_uleb128 (ib);
  expected_tag = lto_input_enum (ib, LTO_tags, LTO_NUM_TAGS);

  result = lto_streamer_cache_get (data_in->reader_cache, ix);
  gcc_assert (result
              && TREE_CODE (result) == lto_tag_to_tree_code (expected_tag));

  return result;
}


/* Read a code and class from input block IB and return the
   corresponding builtin.  DATA_IN is as in lto_input_tree.  */

static tree
lto_get_builtin_tree (struct lto_input_block *ib, struct data_in *data_in)
{
  enum built_in_class fclass;
  enum built_in_function fcode;
  const char *asmname;
  tree result;

  fclass = lto_input_enum (ib, built_in_class, BUILT_IN_LAST);
  gcc_assert (fclass == BUILT_IN_NORMAL || fclass == BUILT_IN_MD);

  fcode = (enum built_in_function) lto_input_uleb128 (ib);

  if (fclass == BUILT_IN_NORMAL)
    {
      if (fcode >= END_BUILTINS)
        fatal_error ("machine independent builtin code out of range");
      result = built_in_decls[fcode];
      gcc_assert (result);
    }
  else if (fclass == BUILT_IN_MD)
    {
      result = targetm.builtin_decl (fcode, true);
      if (!result || result == error_mark_node)
        fatal_error ("target specific builtin not available");
    }
  else
    gcc_unreachable ();

  asmname = lto_input_string (data_in, ib);
  if (asmname)
    set_builtin_user_assembler_name (result, asmname);

  lto_streamer_cache_append (data_in->reader_cache, result);

  return result;
}


/* 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 (struct lto_input_block *ib, struct data_in *data_in)
{
  enum LTO_tags tag;
  tree result;

  tag = input_record_start (ib);
  gcc_assert ((unsigned) tag < (unsigned) LTO_NUM_TAGS);

  if (tag == LTO_null)
    result = NULL_TREE;
  else if (tag >= LTO_field_decl_ref && tag <= LTO_global_decl_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 = lto_get_pickled_tree (ib, data_in);
    }
  else if (tag == LTO_builtin_decl)
    {
      /* If we are going to read a built-in function, all we need is
         the code and class.  */
      result = lto_get_builtin_tree (ib, data_in);
    }
  else if (tag == lto_tree_code_to_tag (INTEGER_CST))
    {
      /* For integer constants we only need the type and its hi/low
         words.  */
      result = lto_input_integer_cst (ib, data_in);
    }
  else
    {
      /* Otherwise, materialize a new node from IB.  */
      result = lto_read_tree (ib, data_in, tag);
    }

  return result;
}