lto-symtab.c (lto_varpool_replace_node): Remove code handling extra name aliases.

[thirdparty/gcc.git] / gcc / cgraphbuild.c

/* Callgraph construction.
   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   Free Software Foundation, Inc.
   Contributed by Jan Hubicka

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 "tree.h"
#include "tree-flow.h"
#include "langhooks.h"
#include "pointer-set.h"
#include "cgraph.h"
#include "intl.h"
#include "gimple.h"
#include "tree-pass.h"
#include "ipa-utils.h"
#include "except.h"
#include "ipa-inline.h"

/* Context of record_reference.  */
struct record_reference_ctx
{
  bool only_vars;
  struct varpool_node *varpool_node;
};

/* Walk tree and record all calls and references to functions/variables.
   Called via walk_tree: TP is pointer to tree to be examined.
   When DATA is non-null, record references to callgraph.
   */

static tree
record_reference (tree *tp, int *walk_subtrees, void *data)
{
  tree t = *tp;
  tree decl;
  struct record_reference_ctx *ctx = (struct record_reference_ctx *)data;

  t = canonicalize_constructor_val (t);
  if (!t)
    t = *tp;
  else if (t != *tp)
    *tp = t;

  switch (TREE_CODE (t))
    {
    case VAR_DECL:
    case FUNCTION_DECL:
      gcc_unreachable ();
      break;

    case FDESC_EXPR:
    case ADDR_EXPR:
      /* Record dereferences to the functions.  This makes the
         functions reachable unconditionally.  */
      decl = get_base_var (*tp);
      if (TREE_CODE (decl) == FUNCTION_DECL)
        {
          struct cgraph_node *node = cgraph_get_create_node (decl);
          if (!ctx->only_vars)
            cgraph_mark_address_taken_node (node);
          ipa_record_reference (NULL, ctx->varpool_node, node, NULL,
                                IPA_REF_ADDR, NULL);
        }

      if (TREE_CODE (decl) == VAR_DECL)
        {
          struct varpool_node *vnode = varpool_node (decl);
          if (lang_hooks.callgraph.analyze_expr)
            lang_hooks.callgraph.analyze_expr (&decl, walk_subtrees);
          varpool_mark_needed_node (vnode);
          ipa_record_reference (NULL, ctx->varpool_node,
                                NULL, vnode,
                                IPA_REF_ADDR, NULL);
        }
      *walk_subtrees = 0;
      break;

    default:
      /* Save some cycles by not walking types and declaration as we
         won't find anything useful there anyway.  */
      if (IS_TYPE_OR_DECL_P (*tp))
        {
          *walk_subtrees = 0;
          break;
        }

      if ((unsigned int) TREE_CODE (t) >= LAST_AND_UNUSED_TREE_CODE)
        return lang_hooks.callgraph.analyze_expr (tp, walk_subtrees);
      break;
    }

  return NULL_TREE;
}

/* Record references to typeinfos in the type list LIST.  */

static void
record_type_list (struct cgraph_node *node, tree list)
{
  for (; list; list = TREE_CHAIN (list))
    {
      tree type = TREE_VALUE (list);
      
      if (TYPE_P (type))
        type = lookup_type_for_runtime (type);
      STRIP_NOPS (type);
      if (TREE_CODE (type) == ADDR_EXPR)
        {
          type = TREE_OPERAND (type, 0);
          if (TREE_CODE (type) == VAR_DECL)
            {
              struct varpool_node *vnode = varpool_node (type);
              varpool_mark_needed_node (vnode);
              ipa_record_reference (node, NULL,
                                    NULL, vnode,
                                    IPA_REF_ADDR, NULL);
            }
        }
    }
}

/* Record all references we will introduce by producing EH tables
   for NODE.  */

static void
record_eh_tables (struct cgraph_node *node, struct function *fun)
{
  eh_region i;

  if (DECL_FUNCTION_PERSONALITY (node->decl))
    {
      struct cgraph_node *per_node;

      per_node = cgraph_get_create_node (DECL_FUNCTION_PERSONALITY (node->decl));
      ipa_record_reference (node, NULL, per_node, NULL, IPA_REF_ADDR, NULL);
      cgraph_mark_address_taken_node (per_node);
    }

  i = fun->eh->region_tree;
  if (!i)
    return;

  while (1)
    {
      switch (i->type)
        {
        case ERT_CLEANUP:
        case ERT_MUST_NOT_THROW:
          break;

        case ERT_TRY:
          {
            eh_catch c;
            for (c = i->u.eh_try.first_catch; c; c = c->next_catch)
              record_type_list (node, c->type_list);
          }
          break;

        case ERT_ALLOWED_EXCEPTIONS:
          record_type_list (node, i->u.allowed.type_list);
          break;
        }
      /* If there are sub-regions, process them.  */
      if (i->inner)
        i = i->inner;
      /* If there are peers, process them.  */
      else if (i->next_peer)
        i = i->next_peer;
      /* Otherwise, step back up the tree to the next peer.  */
      else
        {
          do
            {
              i = i->outer;
              if (i == NULL)
                return;
            }
          while (i->next_peer == NULL);
          i = i->next_peer;
        }
    }
}

/* Reset inlining information of all incoming call edges of NODE.  */

void
reset_inline_failed (struct cgraph_node *node)
{
  struct cgraph_edge *e;

  for (e = node->callers; e; e = e->next_caller)
    {
      e->callee->global.inlined_to = NULL;
      initialize_inline_failed (e);
    }
}

/* Computes the frequency of the call statement so that it can be stored in
   cgraph_edge.  BB is the basic block of the call statement.  */
int
compute_call_stmt_bb_frequency (tree decl, basic_block bb)
{
  int entry_freq = ENTRY_BLOCK_PTR_FOR_FUNCTION
                     (DECL_STRUCT_FUNCTION (decl))->frequency;
  int freq = bb->frequency;

  if (profile_status_for_function (DECL_STRUCT_FUNCTION (decl)) == PROFILE_ABSENT)
    return CGRAPH_FREQ_BASE;

  if (!entry_freq)
    entry_freq = 1, freq++;

  freq = freq * CGRAPH_FREQ_BASE / entry_freq;
  if (freq > CGRAPH_FREQ_MAX)
    freq = CGRAPH_FREQ_MAX;

  return freq;
}

/* Mark address taken in STMT.  */

static bool
mark_address (gimple stmt, tree addr, void *data)
{
  addr = get_base_address (addr);
  if (TREE_CODE (addr) == FUNCTION_DECL)
    {
      struct cgraph_node *node = cgraph_get_create_node (addr);
      cgraph_mark_address_taken_node (node);
      ipa_record_reference ((struct cgraph_node *)data, NULL,
                            node, NULL,
                            IPA_REF_ADDR, stmt);
    }
  else if (addr && TREE_CODE (addr) == VAR_DECL
           && (TREE_STATIC (addr) || DECL_EXTERNAL (addr)))
    {
      struct varpool_node *vnode = varpool_node (addr);
      int walk_subtrees;

      if (lang_hooks.callgraph.analyze_expr)
        lang_hooks.callgraph.analyze_expr (&addr, &walk_subtrees);
      varpool_mark_needed_node (vnode);
      ipa_record_reference ((struct cgraph_node *)data, NULL,
                            NULL, vnode,
                            IPA_REF_ADDR, stmt);
    }

  return false;
}

/* Mark load of T.  */

static bool
mark_load (gimple stmt, tree t, void *data)
{
  t = get_base_address (t);
  if (t && TREE_CODE (t) == FUNCTION_DECL)
    {
      /* ??? This can happen on platforms with descriptors when these are
         directly manipulated in the code.  Pretend that it's an address.  */
      struct cgraph_node *node = cgraph_get_create_node (t);
      cgraph_mark_address_taken_node (node);
      ipa_record_reference ((struct cgraph_node *)data, NULL,
                            node, NULL,
                            IPA_REF_ADDR, stmt);
    }
  else if (t && TREE_CODE (t) == VAR_DECL
           && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
    {
      struct varpool_node *vnode = varpool_node (t);
      int walk_subtrees;

      if (lang_hooks.callgraph.analyze_expr)
        lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
      varpool_mark_needed_node (vnode);
      ipa_record_reference ((struct cgraph_node *)data, NULL,
                            NULL, vnode,
                            IPA_REF_LOAD, stmt);
    }
  return false;
}

/* Mark store of T.  */

static bool
mark_store (gimple stmt, tree t, void *data)
{
  t = get_base_address (t);
  if (t && TREE_CODE (t) == VAR_DECL
      && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
    {
      struct varpool_node *vnode = varpool_node (t);
      int walk_subtrees;

      if (lang_hooks.callgraph.analyze_expr)
        lang_hooks.callgraph.analyze_expr (&t, &walk_subtrees);
      varpool_mark_needed_node (vnode);
      ipa_record_reference ((struct cgraph_node *)data, NULL,
                            NULL, vnode,
                            IPA_REF_STORE, stmt);
     }
  return false;
}

/* Create cgraph edges for function calls.
   Also look for functions and variables having addresses taken.  */

static unsigned int
build_cgraph_edges (void)
{
  basic_block bb;
  struct cgraph_node *node = cgraph_get_node (current_function_decl);
  struct pointer_set_t *visited_nodes = pointer_set_create ();
  gimple_stmt_iterator gsi;
  tree decl;
  unsigned ix;

  /* Create the callgraph edges and record the nodes referenced by the function.
     body.  */
  FOR_EACH_BB (bb)
    {
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          gimple stmt = gsi_stmt (gsi);
          tree decl;

          if (is_gimple_call (stmt))
            {
              int freq = compute_call_stmt_bb_frequency (current_function_decl,
                                                         bb);
              decl = gimple_call_fndecl (stmt);
              if (decl)
                cgraph_create_edge (node, cgraph_get_create_node (decl),
                                    stmt, bb->count, freq);
              else
                cgraph_create_indirect_edge (node, stmt,
                                             gimple_call_flags (stmt),
                                             bb->count, freq);
            }
          walk_stmt_load_store_addr_ops (stmt, node, mark_load,
                                         mark_store, mark_address);
          if (gimple_code (stmt) == GIMPLE_OMP_PARALLEL
              && gimple_omp_parallel_child_fn (stmt))
            {
              tree fn = gimple_omp_parallel_child_fn (stmt);
              ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
                                    NULL, IPA_REF_ADDR, stmt);
            }
          if (gimple_code (stmt) == GIMPLE_OMP_TASK)
            {
              tree fn = gimple_omp_task_child_fn (stmt);
              if (fn)
                ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
                                      NULL, IPA_REF_ADDR, stmt);
              fn = gimple_omp_task_copy_fn (stmt);
              if (fn)
                ipa_record_reference (node, NULL, cgraph_get_create_node (fn),
                                      NULL, IPA_REF_ADDR, stmt);
            }
        }
      for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
        walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
                                       mark_load, mark_store, mark_address);
   }

  /* Look for initializers of constant variables and private statics.  */
  FOR_EACH_LOCAL_DECL (cfun, ix, decl)
    if (TREE_CODE (decl) == VAR_DECL
        && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl)))
      varpool_finalize_decl (decl);
  record_eh_tables (node, cfun);

  pointer_set_destroy (visited_nodes);
  return 0;
}

struct gimple_opt_pass pass_build_cgraph_edges =
{
 {
  GIMPLE_PASS,
  "*build_cgraph_edges",                        /* name */
  NULL,                                 /* gate */
  build_cgraph_edges,                   /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_NONE,                              /* tv_id */
  PROP_cfg,                             /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0                                     /* todo_flags_finish */
 }
};

/* Record references to functions and other variables present in the
   initial value of DECL, a variable.
   When ONLY_VARS is true, we mark needed only variables, not functions.  */

void
record_references_in_initializer (tree decl, bool only_vars)
{
  struct pointer_set_t *visited_nodes = pointer_set_create ();
  struct varpool_node *node = varpool_node (decl);
  struct record_reference_ctx ctx = {false, NULL};

  ctx.varpool_node = node;
  ctx.only_vars = only_vars;
  walk_tree (&DECL_INITIAL (decl), record_reference,
             &ctx, visited_nodes);
  pointer_set_destroy (visited_nodes);
}

/* Rebuild cgraph edges for current function node.  This needs to be run after
   passes that don't update the cgraph.  */

unsigned int
rebuild_cgraph_edges (void)
{
  basic_block bb;
  struct cgraph_node *node = cgraph_get_node (current_function_decl);
  gimple_stmt_iterator gsi;

  cgraph_node_remove_callees (node);
  ipa_remove_all_references (&node->ref_list);

  node->count = ENTRY_BLOCK_PTR->count;

  FOR_EACH_BB (bb)
    {
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          gimple stmt = gsi_stmt (gsi);
          tree decl;

          if (is_gimple_call (stmt))
            {
              int freq = compute_call_stmt_bb_frequency (current_function_decl,
                                                         bb);
              decl = gimple_call_fndecl (stmt);
              if (decl)
                cgraph_create_edge (node, cgraph_get_create_node (decl), stmt,
                                    bb->count, freq);
              else
                cgraph_create_indirect_edge (node, stmt,
                                             gimple_call_flags (stmt),
                                             bb->count, freq);
            }
          walk_stmt_load_store_addr_ops (stmt, node, mark_load,
                                         mark_store, mark_address);

        }
      for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
        walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
                                       mark_load, mark_store, mark_address);
    }
  record_eh_tables (node, cfun);
  gcc_assert (!node->global.inlined_to);

  return 0;
}

/* Rebuild cgraph edges for current function node.  This needs to be run after
   passes that don't update the cgraph.  */

void
cgraph_rebuild_references (void)
{
  basic_block bb;
  struct cgraph_node *node = cgraph_get_node (current_function_decl);
  gimple_stmt_iterator gsi;

  ipa_remove_all_references (&node->ref_list);

  node->count = ENTRY_BLOCK_PTR->count;

  FOR_EACH_BB (bb)
    {
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
        {
          gimple stmt = gsi_stmt (gsi);

          walk_stmt_load_store_addr_ops (stmt, node, mark_load,
                                         mark_store, mark_address);

        }
      for (gsi = gsi_start (phi_nodes (bb)); !gsi_end_p (gsi); gsi_next (&gsi))
        walk_stmt_load_store_addr_ops (gsi_stmt (gsi), node,
                                       mark_load, mark_store, mark_address);
    }
  record_eh_tables (node, cfun);
}

struct gimple_opt_pass pass_rebuild_cgraph_edges =
{
 {
  GIMPLE_PASS,
  "*rebuild_cgraph_edges",              /* name */
  NULL,                                 /* gate */
  rebuild_cgraph_edges,                 /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_CGRAPH,                            /* tv_id */
  PROP_cfg,                             /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0,                                    /* todo_flags_finish */
 }
};


static unsigned int
remove_cgraph_callee_edges (void)
{
  cgraph_node_remove_callees (cgraph_get_node (current_function_decl));
  return 0;
}

struct gimple_opt_pass pass_remove_cgraph_callee_edges =
{
 {
  GIMPLE_PASS,
  "*remove_cgraph_callee_edges",                /* name */
  NULL,                                 /* gate */
  remove_cgraph_callee_edges,           /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  TV_NONE,                              /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0,                                    /* todo_flags_finish */
 }
};