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/* Miscellaneous utilities for GIMPLE streaming.  Things that are used

   in both input and output are here.

   Copyright 2009, 2010 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:

      gcc_assert (name != NULL);

      if (name[0] == '*')

        name++;

      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_jump_functions:

      return concat (LTO_SECTION_NAME_PREFIX, ".jmpfuncs", 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);