Merge lto branch into trunk.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@152434 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 860 insertions, 0 deletions

diff --git a/gcc/lto-streamer.c b/gcc/lto-streamer.c
new file mode 100644
index 00000000000..36172c03131
--- /dev/null
+++ b/gcc/lto-streamer.c
@@ -0,0 +1,860 @@
+/* Miscellaneous utilities for GIMPLE streaming.  Things that are used
+   in both input and output are here.
+
+   Copyright 2009 Free Software Foundation, Inc.
+   Contributed by Doug Kwan <dougkwan@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 "tm.h"
+#include "toplev.h"
+#include "flags.h"
+#include "tree.h"
+#include "gimple.h"
+#include "tree-flow.h"
+#include "diagnostic.h"
+#include "bitmap.h"
+#include "vec.h"
+#include "lto-streamer.h"
+
+/* Statistics gathered during LTO, WPA and LTRANS.  */
+struct lto_stats_d lto_stats;
+
+/* LTO uses bitmaps with different life-times.  So use a seperate
+   obstack for all LTO bitmaps.  */
+static bitmap_obstack lto_obstack;
+static bool lto_obstack_initialized;
+
+
+/* Return a string representing LTO tag TAG.  */
+
+const char *
+lto_tag_name (enum LTO_tags tag)
+{
+  if (lto_tag_is_tree_code_p (tag))
+    {
+      /* For tags representing tree nodes, return the name of the
+	 associated tree code.  */
+      return tree_code_name[lto_tag_to_tree_code (tag)];
+    }
+
+  if (lto_tag_is_gimple_code_p (tag))
+    {
+      /* For tags representing gimple statements, return the name of
+	 the associated gimple code.  */
+      return gimple_code_name[lto_tag_to_gimple_code (tag)];
+    }
+
+  switch (tag)
+    {
+    case LTO_null:
+      return "LTO_null";
+    case LTO_bb0:
+      return "LTO_bb0";
+    case LTO_bb1:
+      return "LTO_bb1";
+    case LTO_eh_region:
+      return "LTO_eh_region";
+    case LTO_function:
+      return "LTO_function";
+    case LTO_eh_table:
+      return "LTO_eh_table";
+    case LTO_ert_cleanup:
+      return "LTO_ert_cleanup";
+    case LTO_ert_try:
+      return "LTO_ert_try";
+    case LTO_ert_allowed_exceptions:
+      return "LTO_ert_allowed_exceptions";
+    case LTO_ert_must_not_throw:
+      return "LTO_ert_must_not_throw";
+    case LTO_tree_pickle_reference:
+      return "LTO_tree_pickle_reference";
+    case LTO_field_decl_ref:
+      return "LTO_field_decl_ref";
+    case LTO_function_decl_ref:
+      return "LTO_function_decl_ref";
+    case LTO_label_decl_ref:
+      return "LTO_label_decl_ref";
+    case LTO_namespace_decl_ref:
+      return "LTO_namespace_decl_ref";
+    case LTO_result_decl_ref:
+      return "LTO_result_decl_ref";
+    case LTO_ssa_name_ref:
+      return "LTO_ssa_name_ref";
+    case LTO_type_decl_ref:
+      return "LTO_type_decl_ref";
+    case LTO_type_ref:
+      return "LTO_type_ref";
+    case LTO_global_decl_ref:
+      return "LTO_global_decl_ref";
+    default:
+      return "LTO_UNKNOWN";
+    }
+}
+
+
+/* Allocate a bitmap from heap.  Initializes the LTO obstack if necessary.  */
+
+bitmap
+lto_bitmap_alloc (void)
+{
+  if (!lto_obstack_initialized)
+    {
+      bitmap_obstack_initialize (&lto_obstack);
+      lto_obstack_initialized = true;
+    }
+  return BITMAP_ALLOC (&lto_obstack);
+}
+
+/* Free bitmap B.  */
+
+void
+lto_bitmap_free (bitmap b)
+{
+  BITMAP_FREE (b);
+}
+
+
+/* Get a section name for a particular type or name.  The NAME field
+   is only used if SECTION_TYPE is LTO_section_function_body or
+   LTO_static_initializer.  For all others it is ignored.  The callee
+   of this function is responcible to free the returned name.  */
+
+char *
+lto_get_section_name (int section_type, const char *name)
+{
+  switch (section_type)
+    {
+    case LTO_section_function_body:
+      return concat (LTO_SECTION_NAME_PREFIX, name, NULL);
+
+    case LTO_section_static_initializer:
+      return concat (LTO_SECTION_NAME_PREFIX, ".statics", NULL);
+
+    case LTO_section_symtab:
+      return concat (LTO_SECTION_NAME_PREFIX, ".symtab", NULL);
+
+    case LTO_section_decls:
+      return concat (LTO_SECTION_NAME_PREFIX, ".decls", NULL);
+
+    case LTO_section_cgraph:
+      return concat (LTO_SECTION_NAME_PREFIX, ".cgraph", NULL);
+
+    case LTO_section_ipa_pure_const:
+      return concat (LTO_SECTION_NAME_PREFIX, ".pureconst", NULL);
+
+    case LTO_section_ipa_reference:
+      return concat (LTO_SECTION_NAME_PREFIX, ".reference", NULL);
+
+    case LTO_section_wpa_fixup:
+      return concat (LTO_SECTION_NAME_PREFIX, ".wpa_fixup", NULL);
+
+    case LTO_section_opts:
+      return concat (LTO_SECTION_NAME_PREFIX, ".opts", NULL);
+
+    default:
+      internal_error ("bytecode stream: unexpected LTO section %s", name);
+    }
+}
+
+
+/* Show various memory usage statistics related to LTO.  */
+
+void
+print_lto_report (void)
+{
+  const char *s = (flag_lto) ? "LTO" : (flag_wpa) ? "WPA" : "LTRANS";
+  unsigned i;
+
+  fprintf (stderr, "%s statistics\n", s);
+  fprintf (stderr, "[%s] # of input files: "
+	   HOST_WIDE_INT_PRINT_UNSIGNED "\n", s, lto_stats.num_input_files);
+
+  fprintf (stderr, "[%s] # of input cgraph nodes: " 
+	   HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
+	   lto_stats.num_input_cgraph_nodes);
+
+  fprintf (stderr, "[%s] # of function bodies: "
+	   HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
+	   lto_stats.num_function_bodies);
+
+  fprintf (stderr, "[%s] ", s);
+  print_gimple_types_stats ();
+
+  for (i = 0; i < NUM_TREE_CODES; i++)
+    if (lto_stats.num_trees[i])
+      fprintf (stderr, "[%s] # of '%s' objects read: "
+	       HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
+	       tree_code_name[i], lto_stats.num_trees[i]);
+
+  if (flag_lto)
+    {
+      fprintf (stderr, "[%s] Compression: "
+	       HOST_WIDE_INT_PRINT_UNSIGNED " output bytes, "
+	       HOST_WIDE_INT_PRINT_UNSIGNED " compressed bytes", s,
+	       lto_stats.num_output_il_bytes,
+	       lto_stats.num_compressed_il_bytes);
+      if (lto_stats.num_output_il_bytes > 0)
+	{
+	  const float dividend = (float) lto_stats.num_compressed_il_bytes;
+	  const float divisor = (float) lto_stats.num_output_il_bytes;
+	  fprintf (stderr, " (ratio: %f)", dividend / divisor);
+	}
+      fprintf (stderr, "\n");
+    }
+
+  if (flag_wpa)
+    {
+      fprintf (stderr, "[%s] # of output files: "
+	       HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
+	       lto_stats.num_output_files);
+
+      fprintf (stderr, "[%s] # of output cgraph nodes: "
+	       HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
+	       lto_stats.num_output_cgraph_nodes);
+
+      fprintf (stderr, "[%s] # callgraph partitions: "
+	       HOST_WIDE_INT_PRINT_UNSIGNED "\n", s,
+	       lto_stats.num_cgraph_partitions);
+
+      fprintf (stderr, "[%s] Compression: "
+	       HOST_WIDE_INT_PRINT_UNSIGNED " input bytes, "
+	       HOST_WIDE_INT_PRINT_UNSIGNED " uncompressed bytes", s,
+	       lto_stats.num_input_il_bytes,
+	       lto_stats.num_uncompressed_il_bytes);
+      if (lto_stats.num_input_il_bytes > 0)
+	{
+	  const float dividend = (float) lto_stats.num_uncompressed_il_bytes;
+	  const float divisor = (float) lto_stats.num_input_il_bytes;
+	  fprintf (stderr, " (ratio: %f)", dividend / divisor);
+	}
+      fprintf (stderr, "\n");
+    }
+
+  for (i = 0; i < LTO_N_SECTION_TYPES; i++)
+    fprintf (stderr, "[%s] Size of mmap'd section %s: "
+	     HOST_WIDE_INT_PRINT_UNSIGNED " bytes\n", s,
+	     lto_section_name[i], lto_stats.section_size[i]);
+}
+
+
+/* Create a new bitpack.  */
+
+struct bitpack_d *
+bitpack_create (void)
+{
+  return XCNEW (struct bitpack_d);
+}
+
+
+/* Free the memory used by bitpack BP.  */
+
+void
+bitpack_delete (struct bitpack_d *bp)
+{
+  VEC_free (bitpack_word_t, heap, bp->values);
+  free (bp);
+}
+
+
+/* Return an index to the word in bitpack BP that contains the
+   next NBITS.  */
+
+static inline unsigned
+bp_get_next_word (struct bitpack_d *bp, unsigned nbits)
+{
+  unsigned last, ix;
+
+  /* In principle, the next word to use is determined by the
+     number of bits already processed in BP.  */
+  ix = bp->num_bits / BITS_PER_BITPACK_WORD;
+
+  /* All the encoded bit patterns in BP are contiguous, therefore if
+     the next NBITS would straddle over two different words, move the
+     index to the next word and update the number of encoded bits
+     by adding up the hole of unused bits created by this move.  */
+  bp->first_unused_bit %= BITS_PER_BITPACK_WORD;
+  last = bp->first_unused_bit + nbits - 1;
+  if (last >= BITS_PER_BITPACK_WORD)
+    {
+      ix++;
+      bp->num_bits += (BITS_PER_BITPACK_WORD - bp->first_unused_bit);
+      bp->first_unused_bit = 0;
+    }
+
+  return ix;
+}
+
+
+/* Pack NBITS of value VAL into bitpack BP.  */
+
+void
+bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
+{
+  unsigned ix;
+  bitpack_word_t word;
+
+  /* We cannot encode more bits than BITS_PER_BITPACK_WORD.  */
+  gcc_assert (nbits > 0 && nbits <= BITS_PER_BITPACK_WORD);
+
+  /* Compute which word will contain the next NBITS.  */
+  ix = bp_get_next_word (bp, nbits);
+  if (ix >= VEC_length (bitpack_word_t, bp->values))
+    {
+      /* If there is no room left in the last word of the values
+	 array, add a new word.  Additionally, we should only
+	 need to add a single word, since every pack operation cannot
+	 use more bits than fit in a single word.  */
+      gcc_assert (ix < VEC_length (bitpack_word_t, bp->values) + 1);
+      VEC_safe_push (bitpack_word_t, heap, bp->values, 0);
+    }
+
+  /* Grab the last word to pack VAL into.  */
+  word = VEC_index (bitpack_word_t, bp->values, ix);
+
+  /* To fit VAL in WORD, we need to shift VAL to the left to
+     skip the bottom BP->FIRST_UNUSED_BIT bits.  */
+  gcc_assert (BITS_PER_BITPACK_WORD >= bp->first_unused_bit + nbits);
+  val <<= bp->first_unused_bit;
+
+  /* Update WORD with VAL.  */
+  word |= val;
+
+  /* Update BP.  */
+  VEC_replace (bitpack_word_t, bp->values, ix, word);
+  bp->num_bits += nbits;
+  bp->first_unused_bit += nbits;
+}
+
+
+/* Unpack the next NBITS from bitpack BP.  */
+
+bitpack_word_t
+bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
+{
+  bitpack_word_t val, word, mask;
+  unsigned ix;
+
+  /* We cannot decode more bits than BITS_PER_BITPACK_WORD.  */
+  gcc_assert (nbits > 0 && nbits <= BITS_PER_BITPACK_WORD);
+
+  /* Compute which word contains the next NBITS.  */
+  ix = bp_get_next_word (bp, nbits);
+  word = VEC_index (bitpack_word_t, bp->values, ix);
+
+  /* Compute the mask to get NBITS from WORD.  */
+  mask = (nbits == BITS_PER_BITPACK_WORD)
+	 ? (bitpack_word_t) -1
+	 : ((bitpack_word_t) 1 << nbits) - 1;
+
+  /* Shift WORD to the right to skip over the bits already decoded
+     in word.  */
+  word >>= bp->first_unused_bit;
+
+  /* Apply the mask to obtain the requested value.  */
+  val = word & mask;
+
+  /* Update BP->NUM_BITS for the next unpack operation.  */
+  bp->num_bits += nbits;
+  bp->first_unused_bit += nbits;
+
+  return val;
+}
+
+
+/* Check that all the TS_* structures handled by the lto_output_* and
+   lto_input_* routines are exactly ALL the structures defined in
+   treestruct.def.  */
+
+static void
+check_handled_ts_structures (void)
+{
+  bool handled_p[LAST_TS_ENUM];
+  unsigned i;
+
+  memset (&handled_p, 0, sizeof (handled_p));
+
+  /* These are the TS_* structures that are either handled or
+     explicitly ignored by the streamer routines.  */
+  handled_p[TS_BASE] = true;
+  handled_p[TS_COMMON] = true;
+  handled_p[TS_INT_CST] = true;
+  handled_p[TS_REAL_CST] = true;
+  handled_p[TS_FIXED_CST] = true;
+  handled_p[TS_VECTOR] = true;
+  handled_p[TS_STRING] = true;
+  handled_p[TS_COMPLEX] = true;
+  handled_p[TS_IDENTIFIER] = true;
+  handled_p[TS_DECL_MINIMAL] = true;
+  handled_p[TS_DECL_COMMON] = true;
+  handled_p[TS_DECL_WRTL] = true;
+  handled_p[TS_DECL_NON_COMMON] = true;
+  handled_p[TS_DECL_WITH_VIS] = true;
+  handled_p[TS_FIELD_DECL] = true;
+  handled_p[TS_VAR_DECL] = true;
+  handled_p[TS_PARM_DECL] = true;
+  handled_p[TS_LABEL_DECL] = true;
+  handled_p[TS_RESULT_DECL] = true;
+  handled_p[TS_CONST_DECL] = true;
+  handled_p[TS_TYPE_DECL] = true;
+  handled_p[TS_FUNCTION_DECL] = true;
+  handled_p[TS_TYPE] = true;
+  handled_p[TS_LIST] = true;
+  handled_p[TS_VEC] = true;
+  handled_p[TS_EXP] = true;
+  handled_p[TS_SSA_NAME] = true;
+  handled_p[TS_BLOCK] = true;
+  handled_p[TS_BINFO] = true;
+  handled_p[TS_STATEMENT_LIST] = true;
+  handled_p[TS_CONSTRUCTOR] = true;
+  handled_p[TS_OMP_CLAUSE] = true;
+  handled_p[TS_OPTIMIZATION] = true;
+  handled_p[TS_TARGET_OPTION] = true;
+
+  /* Anything not marked above will trigger the following assertion.
+     If this assertion triggers, it means that there is a new TS_*
+     structure that should be handled by the streamer.  */
+  for (i = 0; i < LAST_TS_ENUM; i++)
+    gcc_assert (handled_p[i]);
+}
+
+
+/* Helper for lto_streamer_cache_insert_1.  Add T to CACHE->NODES at
+   slot IX.  Add OFFSET to CACHE->OFFSETS at slot IX.  */
+
+static void
+lto_streamer_cache_add_to_node_array (struct lto_streamer_cache_d *cache,
+				      int ix, tree t, unsigned offset)
+{
+  gcc_assert (ix >= 0);
+
+  /* Grow the array of nodes and offsets to accomodate T at IX.  */
+  if (ix >= (int) VEC_length (tree, cache->nodes))
+    {
+      size_t sz = ix + (20 + ix) / 4;
+      VEC_safe_grow_cleared (tree, gc, cache->nodes, sz);
+      VEC_safe_grow_cleared (unsigned, heap, cache->offsets, sz);
+    }
+
+  VEC_replace (tree, cache->nodes, ix, t);
+  VEC_replace (unsigned, cache->offsets, ix, offset);
+}
+
+
+/* Helper for lto_streamer_cache_insert and lto_streamer_cache_insert_at.
+   CACHE, T, IX_P and OFFSET_P are as in lto_streamer_cache_insert.
+
+   If INSERT_AT_NEXT_SLOT_P is true, T is inserted at the next available
+   slot in the cache.  Otherwise, T is inserted at the position indicated
+   in *IX_P.
+
+   If T already existed in CACHE, return true.  Otherwise,
+   return false.  */
+
+static bool
+lto_streamer_cache_insert_1 (struct lto_streamer_cache_d *cache,
+			     tree t, int *ix_p, unsigned *offset_p,
+			     bool insert_at_next_slot_p)
+{
+  void **slot;
+  struct tree_int_map d_entry, *entry;
+  int ix;
+  unsigned offset;
+  bool existed_p;
+
+  gcc_assert (t);
+
+  d_entry.base.from = t;
+  slot = htab_find_slot (cache->node_map, &d_entry, INSERT);
+  if (*slot == NULL)
+    {
+      /* Determine the next slot to use in the cache.  */
+      if (insert_at_next_slot_p)
+	ix = cache->next_slot++;
+      else
+	ix = *ix_p;
+
+      entry = XCNEW (struct tree_int_map);
+      entry->base.from = t;
+      entry->to = (unsigned) ix;
+      *slot = entry;
+
+      /* If no offset was given, store the invalid offset -1.  */
+      offset = (offset_p) ? *offset_p : (unsigned) -1;
+
+      lto_streamer_cache_add_to_node_array (cache, ix, t, offset);
+
+      /* Indicate that the item was not present in the cache.  */
+      existed_p = false;
+    }
+  else
+    {
+      entry = (struct tree_int_map *) *slot;
+      ix = (int) entry->to;
+      offset = VEC_index (unsigned, cache->offsets, ix);
+
+      if (!insert_at_next_slot_p && ix != *ix_p)
+	{
+	  /* If the caller wants to insert T at a specific slot
+	     location, and ENTRY->TO does not match *IX_P, add T to
+	     the requested location slot.  This situation arises when
+	     streaming builtin functions.
+
+	     For instance, on the writer side we could have two
+	     FUNCTION_DECLS T1 and T2 that are represented by the same
+	     builtin function.  The reader will only instantiate the
+	     canonical builtin, but since T1 and T2 had been
+	     originally stored in different cache slots (S1 and S2),
+	     the reader must be able to find the canonical builtin
+	     function at slots S1 and S2.  */
+	  gcc_assert (lto_stream_as_builtin_p (t));
+	  ix = *ix_p;
+
+	  /* Since we are storing a builtin, the offset into the
+	     stream is not necessary as we will not need to read
+	     forward in the stream.  */
+	  lto_streamer_cache_add_to_node_array (cache, ix, t, -1);
+	}
+
+      /* Indicate that T was already in the cache.  */
+      existed_p = true;
+    }
+
+  if (ix_p)
+    *ix_p = ix;
+
+  if (offset_p)
+    *offset_p = offset; 
+
+  return existed_p;
+}
+
+
+/* Insert tree node T in CACHE.  If T already existed in the cache
+   return true.  Otherwise, return false.
+
+   If IX_P is non-null, update it with the index into the cache where
+   T has been stored.
+
+   *OFFSET_P represents the offset in the stream where T is physically
+   written out.  The first time T is added to the cache, *OFFSET_P is
+   recorded in the cache together with T.  But if T already existed
+   in the cache, *OFFSET_P is updated with the value that was recorded
+   the first time T was added to the cache.
+
+   If OFFSET_P is NULL, it is ignored.  */
+
+bool
+lto_streamer_cache_insert (struct lto_streamer_cache_d *cache, tree t,
+			   int *ix_p, unsigned *offset_p)
+{
+  return lto_streamer_cache_insert_1 (cache, t, ix_p, offset_p, true);
+}
+
+
+/* Insert tree node T in CACHE at slot IX.  If T already
+   existed in the cache return true.  Otherwise, return false.  */
+
+bool
+lto_streamer_cache_insert_at (struct lto_streamer_cache_d *cache,
+			      tree t, int ix)
+{
+  return lto_streamer_cache_insert_1 (cache, t, &ix, NULL, false);
+}
+
+
+/* Return true if tree node T exists in CACHE.  If IX_P is
+   not NULL, write to *IX_P the index into the cache where T is stored
+   (-1 if T is not found).  */
+
+bool
+lto_streamer_cache_lookup (struct lto_streamer_cache_d *cache, tree t,
+			   int *ix_p)
+{
+  void **slot;
+  struct tree_int_map d_slot;
+  bool retval;
+  int ix;
+
+  gcc_assert (t);
+
+  d_slot.base.from = t;
+  slot = htab_find_slot (cache->node_map, &d_slot, NO_INSERT);
+  if (slot == NULL)
+    {
+      retval = false;
+      ix = -1;
+    }
+  else
+    {
+      retval = true;
+      ix = (int) ((struct tree_int_map *) *slot)->to;
+    }
+
+  if (ix_p)
+    *ix_p = ix;
+
+  return retval;
+}
+
+
+/* Return the tree node at slot IX in CACHE.  */
+
+tree
+lto_streamer_cache_get (struct lto_streamer_cache_d *cache, int ix)
+{
+  gcc_assert (cache);
+
+  /* If the reader is requesting an index beyond the length of the
+     cache, it will need to read ahead.  Return NULL_TREE to indicate
+     that.  */
+  if ((unsigned) ix >= VEC_length (tree, cache->nodes))
+    return NULL_TREE;
+
+  return VEC_index (tree, cache->nodes, (unsigned) ix);
+}
+
+
+/* Record NODE in COMMON_NODES if it is not NULL and is not already in
+   SEEN_NODES.  */
+
+static void
+lto_record_common_node (tree *nodep, VEC(tree, heap) **common_nodes,
+			struct pointer_set_t *seen_nodes)
+{
+  tree node = *nodep;
+
+  if (node == NULL_TREE)
+    return;
+
+  if (TYPE_P (node))
+    *nodep = node = gimple_register_type (node);
+
+  /* Return if node is already seen.  */
+  if (pointer_set_insert (seen_nodes, node))
+    return;
+
+  VEC_safe_push (tree, heap, *common_nodes, node);
+
+  if (tree_node_can_be_shared (node))
+    {
+      if (POINTER_TYPE_P (node)
+	  || TREE_CODE (node) == COMPLEX_TYPE
+	  || TREE_CODE (node) == ARRAY_TYPE)
+	lto_record_common_node (&TREE_TYPE (node), common_nodes, seen_nodes);
+    }
+}
+
+
+/* Generate a vector of common nodes and make sure they are merged
+   properly according to the the gimple type table.  */
+
+static VEC(tree,heap) *
+lto_get_common_nodes (void)
+{
+  unsigned i;
+  VEC(tree,heap) *common_nodes = NULL;
+  struct pointer_set_t *seen_nodes;
+
+  /* The MAIN_IDENTIFIER_NODE is normally set up by the front-end, but the
+     LTO back-end must agree. Currently, the only languages that set this
+     use the name "main".  */
+  if (main_identifier_node)
+    {
+      const char *main_name = IDENTIFIER_POINTER (main_identifier_node);
+      gcc_assert (strcmp (main_name, "main") == 0);
+    }
+  else
+    main_identifier_node = get_identifier ("main");
+
+  gcc_assert (ptrdiff_type_node == integer_type_node);
+
+  /* FIXME lto.  In the C++ front-end, fileptr_type_node is defined as a
+     variant copy of of ptr_type_node, rather than ptr_node itself.  The
+     distinction should only be relevant to the front-end, so we always
+     use the C definition here in lto1.
+
+     These should be assured in pass_ipa_free_lang_data.  */
+  gcc_assert (fileptr_type_node == ptr_type_node);
+  gcc_assert (TYPE_MAIN_VARIANT (fileptr_type_node) == ptr_type_node);
+  
+  seen_nodes = pointer_set_create ();
+
+  /* Skip itk_char.  char_type_node is shared with the appropriately
+     signed variant.  */
+  for (i = itk_signed_char; i < itk_none; i++)
+    lto_record_common_node (&integer_types[i], &common_nodes, seen_nodes);
+
+  for (i = 0; i < TYPE_KIND_LAST; i++)
+    lto_record_common_node (&sizetype_tab[i], &common_nodes, seen_nodes);
+
+  for (i = 0; i < TI_MAX; i++)
+    lto_record_common_node (&global_trees[i], &common_nodes, seen_nodes);
+
+  pointer_set_destroy (seen_nodes);
+
+  return common_nodes;
+}
+
+
+/* Assign an index to tree node T and enter it in the streamer cache
+   CACHE.  */
+
+static void
+preload_common_node (struct lto_streamer_cache_d *cache, tree t)
+{
+  gcc_assert (t);
+
+  lto_streamer_cache_insert (cache, t, NULL, NULL);
+
+ /* The FIELD_DECLs of structures should be shared, so that every
+    COMPONENT_REF uses the same tree node when referencing a field.
+    Pointer equality between FIELD_DECLs is used by the alias
+    machinery to compute overlapping memory references (See
+    nonoverlapping_component_refs_p).  */
+ if (TREE_CODE (t) == RECORD_TYPE)
+   {
+     tree f;
+
+     for (f = TYPE_FIELDS (t); f; f = TREE_CHAIN (f))
+       preload_common_node (cache, f);
+   }
+}
+
+
+/* Create a cache of pickled nodes.  */
+
+struct lto_streamer_cache_d *
+lto_streamer_cache_create (void)
+{
+  struct lto_streamer_cache_d *cache;
+  VEC(tree, heap) *common_nodes;
+  unsigned i;
+  tree node;
+
+  cache = XCNEW (struct lto_streamer_cache_d);
+
+  cache->node_map = htab_create (101, tree_int_map_hash, tree_int_map_eq, NULL);
+
+  /* Load all the well-known tree nodes that are always created by
+     the compiler on startup.  This prevents writing them out
+     unnecessarily.  */
+  common_nodes = lto_get_common_nodes ();
+
+  for (i = 0; VEC_iterate (tree, common_nodes, i, node); i++)
+    preload_common_node (cache, node);
+
+  VEC_free(tree, heap, common_nodes);
+
+  return cache;
+}
+
+
+/* Delete the streamer cache C.  */
+
+void
+lto_streamer_cache_delete (struct lto_streamer_cache_d *c)
+{
+  if (c == NULL)
+    return;
+
+  htab_delete (c->node_map);
+  VEC_free (tree, gc, c->nodes);
+  VEC_free (unsigned, heap, c->offsets);
+  free (c);
+}
+
+
+/* Initialization common to the LTO reader and writer.  */
+
+void
+lto_streamer_init (void)
+{
+  /* Check that all the TS_* handled by the reader and writer routines
+     match exactly the structures defined in treestruct.def.  When a
+     new TS_* astructure is added, the streamer should be updated to
+     handle it.  */
+  check_handled_ts_structures ();
+}
+
+
+/* Gate function for all LTO streaming passes.  */
+
+bool
+gate_lto_out (void)
+{
+  return ((flag_generate_lto || in_lto_p)
+	  /* Don't bother doing anything if the program has errors.  */
+	  && !(errorcount || sorrycount));
+}
+
+
+#ifdef LTO_STREAMER_DEBUG
+/* Add a mapping between T and ORIG_T, which is the numeric value of
+   the original address of T as it was seen by the LTO writer.  This
+   mapping is useful when debugging streaming problems.  A debugging
+   session can be started on both reader and writer using ORIG_T
+   as a breakpoint value in both sessions.
+
+   Note that this mapping is transient and only valid while T is 
+   being reconstructed.  Once T is fully built, the mapping is
+   removed.  */
+
+void
+lto_orig_address_map (tree t, intptr_t orig_t)
+{
+  /* FIXME lto.  Using the annotation field is quite hacky as it relies
+     on the GC not running while T is being rematerialized.  It would
+     be cleaner to use a hash table here.  */
+  t->base.ann = (union tree_ann_d *) orig_t;
+}
+
+
+/* Get the original address of T as it was seen by the writer.  This
+   is only valid while T is being reconstructed.  */
+
+intptr_t
+lto_orig_address_get (tree t)
+{
+  return (intptr_t) t->base.ann;
+}
+
+
+/* Clear the mapping of T to its original address.  */
+
+void
+lto_orig_address_remove (tree t)
+{
+  t->base.ann = NULL;
+}
+#endif
+
+
+/* Check that the version MAJOR.MINOR is the correct version number.  */
+
+void
+lto_check_version (int major, int minor)
+{
+  if (major != LTO_major_version || minor != LTO_minor_version)
+    fatal_error ("bytecode stream generated with LTO version %d.%d instead "
+	         "of the expected %d.%d",
+		 major, minor,
+		 LTO_major_version, LTO_minor_version);
+}