C++ ENTRY_BLOCK_PTR_FOR_FN函數代碼示例

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

  /* Keep speculative references for further cgraph edge expansion.  */
  for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list, i, ref);)
    if (!ref->speculative)
      ipa_remove_reference (ref);
    else
      i++;

  node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;

  FOR_EACH_BB_FN (bb, cfun)
    {
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	ipa_record_stmt_references (node, gsi_stmt (gsi));
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	ipa_record_stmt_references (node, gsi_stmt (gsi));
    }
  record_eh_tables (node, cfun);
}

static void
compute_farthest (struct edge_list *edge_list, int n_exprs,
		  sbitmap *st_avout, sbitmap *st_avin, sbitmap *st_antin,
		  sbitmap *kill, sbitmap *farthest)
{
  int x, num_edges;
  basic_block pred, succ;

  num_edges = NUM_EDGES (edge_list);

  auto_sbitmap difference (n_exprs), temp_bitmap (n_exprs);
  for (x = 0; x < num_edges; x++)
    {
      pred = INDEX_EDGE_PRED_BB (edge_list, x);
      succ = INDEX_EDGE_SUCC_BB (edge_list, x);
      if (succ == EXIT_BLOCK_PTR_FOR_FN (cfun))
	bitmap_copy (farthest[x], st_avout[pred->index]);
      else
	{
	  if (pred == ENTRY_BLOCK_PTR_FOR_FN (cfun))
	    bitmap_clear (farthest[x]);
	  else
	    {
	      bitmap_and_compl (difference, st_avout[pred->index],
				  st_antin[succ->index]);
	      bitmap_not (temp_bitmap, st_avin[succ->index]);
	      bitmap_and_or (farthest[x], difference,
				    kill[succ->index], temp_bitmap);
	    }
	}
    }
}

static unsigned int
tree_optimize_tail_calls_1 (bool opt_tailcalls)
{
  edge e;
  bool phis_constructed = false;
  struct tailcall *tailcalls = NULL, *act, *next;
  bool changed = false;
  basic_block first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
  tree param;
  gimple stmt;
  edge_iterator ei;

  if (!suitable_for_tail_opt_p ())
    return 0;
  if (opt_tailcalls)
    opt_tailcalls = suitable_for_tail_call_opt_p ();

  FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)
    {
      /* Only traverse the normal exits, i.e. those that end with return
	 statement.  */
      stmt = last_stmt (e->src);

      if (stmt
	  && gimple_code (stmt) == GIMPLE_RETURN)
	find_tail_calls (e->src, &tailcalls);
    }

static unsigned int execute_stackleak_tree_instrument(void)
{
	basic_block bb, entry_bb;
	bool prologue_instrumented = false, is_leaf = true;

	entry_bb = ENTRY_BLOCK_PTR_FOR_FN(cfun)->next_bb;

	// 1. loop through BBs and GIMPLE statements
	FOR_EACH_BB_FN(bb, cfun) {
		gimple_stmt_iterator gsi;

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

			stmt = gsi_stmt(gsi);

			if (is_gimple_call(stmt))
				is_leaf = false;

			// gimple match: align 8 built-in BUILT_IN_NORMAL:BUILT_IN_ALLOCA attributes <tree_list 0xb7576450>
			if (!is_alloca(stmt))
				continue;

			// 2. insert stack overflow check before each __builtin_alloca call
			stackleak_check_alloca(&gsi);

			// 3. insert track call after each __builtin_alloca call
			stackleak_add_instrumentation(&gsi);
			if (bb == entry_bb)
				prologue_instrumented = true;
		}
	}

void
cgraph_edge::rebuild_references (void)
{
  basic_block bb;
  cgraph_node *node = cgraph_node::get (current_function_decl);
  gimple_stmt_iterator gsi;
  ipa_ref *ref = NULL;
  int i;

  /* Keep speculative references for further cgraph edge expansion.  */
  for (i = 0; node->iterate_reference (i, ref);)
    if (!ref->speculative)
      ref->remove_reference ();
    else
      i++;

  node->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count;

  FOR_EACH_BB_FN (bb, cfun)
    {
      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	node->record_stmt_references (gsi_stmt (gsi));
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	node->record_stmt_references (gsi_stmt (gsi));
    }
  record_eh_tables (node, cfun);

  if (node->instrumented_version
      && !node->instrumentation_clone)
    node->create_reference (node->instrumented_version, IPA_REF_CHKP, NULL);
}

static bool
reachable_at_most_once (basic_block va_arg_bb, basic_block va_start_bb)
{
  vec<edge> stack = vNULL;
  edge e;
  edge_iterator ei;
  sbitmap visited;
  bool ret;

  if (va_arg_bb == va_start_bb)
    return true;

  if (! dominated_by_p (CDI_DOMINATORS, va_arg_bb, va_start_bb))
    return false;

  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
  bitmap_clear (visited);
  ret = true;

  FOR_EACH_EDGE (e, ei, va_arg_bb->preds)
    stack.safe_push (e);

  while (! stack.is_empty ())
    {
      basic_block src;

      e = stack.pop ();
      src = e->src;

      if (e->flags & EDGE_COMPLEX)
	{
	  ret = false;
	  break;
	}

      if (src == va_start_bb)
	continue;

      /* va_arg_bb can be executed more times than va_start_bb.  */
      if (src == va_arg_bb)
	{
	  ret = false;
	  break;
	}

      gcc_assert (src != ENTRY_BLOCK_PTR_FOR_FN (cfun));

      if (! bitmap_bit_p (visited, src->index))
	{
	  bitmap_set_bit (visited, src->index);
	  FOR_EACH_EDGE (e, ei, src->preds)
	    stack.safe_push (e);
	}
    }

  stack.release ();
  sbitmap_free (visited);
  return ret;
}

void
init_flow (struct function *the_fun)
{
  if (!the_fun->cfg)
    the_fun->cfg = ggc_cleared_alloc<control_flow_graph> ();
  n_edges_for_fn (the_fun) = 0;
  ENTRY_BLOCK_PTR_FOR_FN (the_fun)
    = ggc_cleared_alloc<basic_block_def> ();
  ENTRY_BLOCK_PTR_FOR_FN (the_fun)->index = ENTRY_BLOCK;
  EXIT_BLOCK_PTR_FOR_FN (the_fun)
    = ggc_cleared_alloc<basic_block_def> ();
  EXIT_BLOCK_PTR_FOR_FN (the_fun)->index = EXIT_BLOCK;
  ENTRY_BLOCK_PTR_FOR_FN (the_fun)->next_bb
    = EXIT_BLOCK_PTR_FOR_FN (the_fun);
  EXIT_BLOCK_PTR_FOR_FN (the_fun)->prev_bb
    = ENTRY_BLOCK_PTR_FOR_FN (the_fun);
}

void
gimple_gen_ic_func_profiler (void)
{
  struct cgraph_node * c_node = cgraph_node::get (current_function_decl);
  gimple_stmt_iterator gsi;
  gcall *stmt1;
  gassign *stmt2;
  tree tree_uid, cur_func, void0;

  if (c_node->only_called_directly_p ())
    return;

  gimple_init_edge_profiler ();

  /* Insert code:

    stmt1: __gcov_indirect_call_profiler_v2 (profile_id,
					     &current_function_decl)
   */
  gsi = gsi_after_labels (split_edge (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun))));

  cur_func = force_gimple_operand_gsi (&gsi,
				       build_addr (current_function_decl,
						   current_function_decl),
				       true, NULL_TREE,
				       true, GSI_SAME_STMT);
  tree_uid = build_int_cst
	      (gcov_type_node, cgraph_node::get (current_function_decl)->profile_id);
  /* Workaround for binutils bug 14342.  Once it is fixed, remove lto path.  */
  if (flag_lto)
    {
      tree counter_ptr, ptr_var;
      counter_ptr = force_gimple_operand_gsi (&gsi, ic_gcov_type_ptr_var,
					      true, NULL_TREE, true,
					      GSI_SAME_STMT);
      ptr_var = force_gimple_operand_gsi (&gsi, ic_void_ptr_var,
					  true, NULL_TREE, true,
					  GSI_SAME_STMT);

      stmt1 = gimple_build_call (tree_indirect_call_profiler_fn, 4,
				 counter_ptr, tree_uid, cur_func, ptr_var);
    }
  else
    {
      stmt1 = gimple_build_call (tree_indirect_call_profiler_fn, 2,
				 tree_uid, cur_func);
    }
  gsi_insert_before (&gsi, stmt1, GSI_SAME_STMT);

  /* Set __gcov_indirect_call_callee to 0,
     so that calls from other modules won't get misattributed
     to the last caller of the current callee. */
  void0 = build_int_cst (build_pointer_type (void_type_node), 0);
  stmt2 = gimple_build_assign (ic_void_ptr_var, void0);
  gsi_insert_before (&gsi, stmt2, GSI_SAME_STMT);
}

void
init_flow (struct function *the_fun)
{
  if (!the_fun->cfg)
    the_fun->cfg = ggc_cleared_alloc<control_flow_graph> ();
  n_edges_for_fn (the_fun) = 0;
  the_fun->cfg->count_max = profile_count::uninitialized ();
  ENTRY_BLOCK_PTR_FOR_FN (the_fun)
    = alloc_block ();
  ENTRY_BLOCK_PTR_FOR_FN (the_fun)->index = ENTRY_BLOCK;
  EXIT_BLOCK_PTR_FOR_FN (the_fun)
    = alloc_block ();
  EXIT_BLOCK_PTR_FOR_FN (the_fun)->index = EXIT_BLOCK;
  ENTRY_BLOCK_PTR_FOR_FN (the_fun)->next_bb
    = EXIT_BLOCK_PTR_FOR_FN (the_fun);
  EXIT_BLOCK_PTR_FOR_FN (the_fun)->prev_bb
    = ENTRY_BLOCK_PTR_FOR_FN (the_fun);
  the_fun->cfg->edge_flags_allocated = EDGE_ALL_FLAGS;
  the_fun->cfg->bb_flags_allocated = BB_ALL_FLAGS;
}

void
gsi_commit_edge_inserts (void)
{
  basic_block bb;
  edge e;
  edge_iterator ei;

  gsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)),
			      NULL);

  FOR_EACH_BB_FN (bb, cfun)
    FOR_EACH_EDGE (e, ei, bb->succs)
      gsi_commit_one_edge_insert (e, NULL);
}

static void
cfg_blocks_add (basic_block bb)
{
  bool head = false;

  gcc_assert (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
	      && bb != EXIT_BLOCK_PTR_FOR_FN (cfun));
  gcc_assert (!bitmap_bit_p (bb_in_list, bb->index));

  if (cfg_blocks_empty_p ())
    {
      cfg_blocks_tail = cfg_blocks_head = 0;
      cfg_blocks_num = 1;
    }
  else
    {
      cfg_blocks_num++;
      if (cfg_blocks_num > cfg_blocks.length ())
	{
	  /* We have to grow the array now.  Adjust to queue to occupy
	     the full space of the original array.  We do not need to
	     initialize the newly allocated portion of the array
	     because we keep track of CFG_BLOCKS_HEAD and
	     CFG_BLOCKS_HEAD.  */
	  cfg_blocks_tail = cfg_blocks.length ();
	  cfg_blocks_head = 0;
	  cfg_blocks.safe_grow (2 * cfg_blocks_tail);
	}
      /* Minor optimization: we prefer to see blocks with more
	 predecessors later, because there is more of a chance that
	 the incoming edges will be executable.  */
      else if (EDGE_COUNT (bb->preds)
	       >= EDGE_COUNT (cfg_blocks[cfg_blocks_head]->preds))
	cfg_blocks_tail = ((cfg_blocks_tail + 1) % cfg_blocks.length ());
      else
	{
	  if (cfg_blocks_head == 0)
	    cfg_blocks_head = cfg_blocks.length ();
	  --cfg_blocks_head;
	  head = true;
	}
    }

  cfg_blocks[head ? cfg_blocks_head : cfg_blocks_tail] = bb;
  bitmap_set_bit (bb_in_list, bb->index);
}

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_FOR_FN (cfun)->count;

  FOR_EACH_BB_FN (bb, cfun)
    {
      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 if (gimple_call_internal_p (stmt))
		;
	      else
		cgraph_create_indirect_edge (node, stmt,
					     gimple_call_flags (stmt),
					     bb->count, freq);
	    }
	  ipa_record_stmt_references (node, stmt);
	}
      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
	ipa_record_stmt_references (node, gsi_stmt (gsi));
    }
  record_eh_tables (node, cfun);
  gcc_assert (!node->global.inlined_to);

  return 0;
}

/* 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_FN
  		     (DECL_STRUCT_FUNCTION (decl))->frequency;
  int freq = bb->frequency;

  if (profile_status_for_fn (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;
}

static void
verify_three_block_cfg (function *fun)
{
  ASSERT_TRUE (fun->cfg != NULL);
  ASSERT_EQ (3, n_basic_blocks_for_fn (fun));
  ASSERT_EQ (2, n_edges_for_fn (fun));

  /* The "fake" basic blocks.  */
  basic_block entry = ENTRY_BLOCK_PTR_FOR_FN (fun);
  ASSERT_TRUE (entry != NULL);
  ASSERT_EQ (ENTRY_BLOCK, entry->index);

  basic_block exit = EXIT_BLOCK_PTR_FOR_FN (fun);
  ASSERT_TRUE (exit != NULL);
  ASSERT_EQ (EXIT_BLOCK, exit->index);

  /* The "real" basic block.  */
  basic_block bb2 = get_real_block (fun);
  ASSERT_TRUE (bb2 != NULL);
  ASSERT_EQ (2, bb2->index);

  /* Verify connectivity.  */
  ASSERT_EQ (NULL, entry->preds);
  ASSERT_EQ (1, entry->succs->length ());

  edge from_entry_to_bb2 = (*entry->succs)[0];
  ASSERT_EQ (entry, from_entry_to_bb2->src);
  ASSERT_EQ (bb2, from_entry_to_bb2->dest);

  ASSERT_EQ (1, bb2->preds->length ());
  ASSERT_EQ (from_entry_to_bb2, (*bb2->preds)[0]);
  ASSERT_EQ (1, bb2->succs->length ());

  edge from_bb2_to_exit = (*bb2->succs)[0];
  ASSERT_EQ (bb2, from_bb2_to_exit->src);
  ASSERT_EQ (exit, from_bb2_to_exit->dest);

  ASSERT_EQ (1, exit->preds->length ());
  ASSERT_EQ (from_bb2_to_exit, (*exit->preds)[0]);
  ASSERT_EQ (NULL, exit->succs);
}

static basic_block
nearest_common_dominator_of_uses (def_operand_p def_p, bool *debug_stmts)
{
  tree var = DEF_FROM_PTR (def_p);
  bitmap blocks = BITMAP_ALLOC (NULL);
  basic_block commondom;
  unsigned int j;
  bitmap_iterator bi;
  imm_use_iterator imm_iter;
  use_operand_p use_p;

  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
    {
      gimple *usestmt = USE_STMT (use_p);
      basic_block useblock;

      if (gphi *phi = dyn_cast <gphi *> (usestmt))
	{
	  int idx = PHI_ARG_INDEX_FROM_USE (use_p);

	  useblock = gimple_phi_arg_edge (phi, idx)->src;
	}
      else if (is_gimple_debug (usestmt))
	{
	  *debug_stmts = true;
	  continue;
	}
      else
	{
	  useblock = gimple_bb (usestmt);
	}

      /* Short circuit. Nothing dominates the entry block.  */
      if (useblock == ENTRY_BLOCK_PTR_FOR_FN (cfun))
	{
	  BITMAP_FREE (blocks);
	  return NULL;
	}
      bitmap_set_bit (blocks, useblock->index);
    }