C++ TREE_SIDE_EFFECTS函数代码示例

void
copy_mem_ref_info (tree to, tree from)
{
  /* And the info about the original reference.  */
  TREE_SIDE_EFFECTS (to) = TREE_SIDE_EFFECTS (from);
  TREE_THIS_VOLATILE (to) = TREE_THIS_VOLATILE (from);
}

tree
build_stmt (enum tree_code code, ...)
{
  tree ret;
  int length, i;
  va_list p;
  bool side_effects;

  va_start (p, code);

  ret = make_node (code);
  TREE_TYPE (ret) = void_type_node;
  length = TREE_CODE_LENGTH (code);
  SET_EXPR_LOCATION (ret, input_location);

  /* TREE_SIDE_EFFECTS will already be set for statements with
     implicit side effects.  Here we make sure it is set for other
     expressions by checking whether the parameters have side
     effects.  */

  side_effects = false;
  for (i = 0; i < length; i++)
    {
      tree t = va_arg (p, tree);
      if (t && !TYPE_P (t))
	side_effects |= TREE_SIDE_EFFECTS (t);
      TREE_OPERAND (ret, i) = t;
    }

  TREE_SIDE_EFFECTS (ret) |= side_effects;

  va_end (p);
  return ret;
}

static void
genericize_if_stmt (tree *stmt_p)
{
  tree stmt, cond, then_, else_;
  location_t locus = EXPR_LOCATION (*stmt_p);

  stmt = *stmt_p;
  cond = IF_COND (stmt);
  then_ = THEN_CLAUSE (stmt);
  else_ = ELSE_CLAUSE (stmt);

  if (!then_)
    then_ = build_empty_stmt ();
  if (!else_)
    else_ = build_empty_stmt ();

  if (integer_nonzerop (cond) && !TREE_SIDE_EFFECTS (else_))
    stmt = then_;
  else if (integer_zerop (cond) && !TREE_SIDE_EFFECTS (then_))
    stmt = else_;
  else
    stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_);
  if (CAN_HAVE_LOCATION_P (stmt) && !EXPR_HAS_LOCATION (stmt))
    SET_EXPR_LOCATION (stmt, locus);
  *stmt_p = stmt;
}

void
copy_ref_info (tree new_ref, tree old_ref)
{
  tree new_ptr_base = NULL_TREE;

  gcc_assert (TREE_CODE (new_ref) == MEM_REF
	      || TREE_CODE (new_ref) == TARGET_MEM_REF);

  TREE_SIDE_EFFECTS (new_ref) = TREE_SIDE_EFFECTS (old_ref);
  TREE_THIS_VOLATILE (new_ref) = TREE_THIS_VOLATILE (old_ref);

  new_ptr_base = TREE_OPERAND (new_ref, 0);

  /* We can transfer points-to information from an old pointer
     or decl base to the new one.  */
  if (new_ptr_base
      && TREE_CODE (new_ptr_base) == SSA_NAME
      && !SSA_NAME_PTR_INFO (new_ptr_base))
    {
      tree base = get_base_address (old_ref);
      if (!base)
	;
      else if ((TREE_CODE (base) == MEM_REF
		|| TREE_CODE (base) == TARGET_MEM_REF)
	       && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME
	       && SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)))
	{
	  struct ptr_info_def *new_pi;
	  unsigned int align, misalign;

	  duplicate_ssa_name_ptr_info
	    (new_ptr_base, SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)));
	  new_pi = SSA_NAME_PTR_INFO (new_ptr_base);
	  /* We have to be careful about transferring alignment information.  */
	  if (get_ptr_info_alignment (new_pi, &align, &misalign)
	      && TREE_CODE (old_ref) == MEM_REF
	      && !(TREE_CODE (new_ref) == TARGET_MEM_REF
		   && (TMR_INDEX2 (new_ref)
		       || (TMR_STEP (new_ref)
			   && (TREE_INT_CST_LOW (TMR_STEP (new_ref))
			       < align)))))
	    {
	      unsigned int inc = (mem_ref_offset (old_ref)
				  - mem_ref_offset (new_ref)).low;
	      adjust_ptr_info_misalignment (new_pi, inc);
	    }
	  else
	    mark_ptr_info_alignment_unknown (new_pi);
	}
      else if (TREE_CODE (base) == VAR_DECL
	       || TREE_CODE (base) == PARM_DECL
	       || TREE_CODE (base) == RESULT_DECL)
	{
	  struct ptr_info_def *pi = get_ptr_info (new_ptr_base);
	  pt_solution_set_var (&pi->pt, base);
	}
    }
}

tree
tsi_split_statement_list_before (tree_stmt_iterator *i)
{
  struct tree_statement_list_node *cur, *prev;
  tree old_sl, new_sl;

  cur = i->ptr;
  /* How can we possibly split after the end, or before the beginning?  */
  gcc_assert (cur);
  prev = cur->prev;

  old_sl = i->container;
  new_sl = alloc_stmt_list ();
  TREE_SIDE_EFFECTS (new_sl) = 1;
  i->container = new_sl;

  STATEMENT_LIST_HEAD (new_sl) = cur;
  STATEMENT_LIST_TAIL (new_sl) = STATEMENT_LIST_TAIL (old_sl);
  STATEMENT_LIST_TAIL (old_sl) = prev;
  cur->prev = NULL;
  if (prev)
    prev->next = NULL;
  else
    STATEMENT_LIST_HEAD (old_sl) = NULL;

  return new_sl;
}

static inline 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
     streamer_alloc_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_NOTHROW (expr) = (unsigned) bp_unpack_value (bp, 1);
  TREE_STATIC (expr) = (unsigned) bp_unpack_value (bp, 1);
  if (TREE_CODE (expr) != TREE_BINFO)
    TREE_PRIVATE (expr) = (unsigned) bp_unpack_value (bp, 1);
  else
    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))
    {
      if (AGGREGATE_TYPE_P (expr))
	TYPE_REVERSE_STORAGE_ORDER (expr) = (unsigned) bp_unpack_value (bp, 1);
      else
	TYPE_SATURATING (expr) = (unsigned) bp_unpack_value (bp, 1);
      TYPE_ADDR_SPACE (expr) = (unsigned) bp_unpack_value (bp, 8);
    }
  else if (TREE_CODE (expr) == BIT_FIELD_REF || TREE_CODE (expr) == MEM_REF)
    {
      REF_REVERSE_STORAGE_ORDER (expr) = (unsigned) bp_unpack_value (bp, 1);
      bp_unpack_value (bp, 8);
    }
  else if (TREE_CODE (expr) == SSA_NAME)
    {
      SSA_NAME_IS_DEFAULT_DEF (expr) = (unsigned) bp_unpack_value (bp, 1);
      bp_unpack_value (bp, 8);
    }
  else
    bp_unpack_value (bp, 9);
}

static void
gimplify_expr_stmt (tree *stmt_p)
{
  tree stmt = EXPR_STMT_EXPR (*stmt_p);

  if (stmt == error_mark_node)
    stmt = NULL;

  /* Gimplification of a statement expression will nullify the
     statement if all its side effects are moved to *PRE_P and *POST_P.

     In this case we will not want to emit the gimplified statement.
     However, we may still want to emit a warning, so we do that before
     gimplification.  */
  if (stmt && (extra_warnings || warn_unused_value))
    {
      if (!TREE_SIDE_EFFECTS (stmt))
	{
	  if (!IS_EMPTY_STMT (stmt)
	      && !VOID_TYPE_P (TREE_TYPE (stmt))
	      && !TREE_NO_WARNING (stmt))
	    warning (0, "statement with no effect");
	}
      else if (warn_unused_value)
	warn_if_unused_value (stmt, input_location);
    }

  if (stmt == NULL_TREE)
    stmt = alloc_stmt_list ();

  *stmt_p = stmt;
}

tree
c_build_bind_expr (tree block, tree body)
{
  tree decls, bind;

  if (block == NULL_TREE)
    decls = NULL_TREE;
  else if (TREE_CODE (block) == BLOCK)
    decls = BLOCK_VARS (block);
  else
    {
      decls = block;
      if (DECL_ARTIFICIAL (decls))
        block = NULL_TREE;
      else
        {
          block = make_node (BLOCK);
          BLOCK_VARS (block) = decls;
          add_block_to_enclosing (block);
        }
    }

  if (!body)
    body = build_empty_stmt ();
  if (decls || block)
    {
      bind = build3 (BIND_EXPR, void_type_node, decls, body, block);
      TREE_SIDE_EFFECTS (bind) = 1;
    }
  else
    bind = body;

  return bind;
}

void
recalculate_side_effects (tree t)
{
  enum tree_code code = TREE_CODE (t);
  int len = TREE_CODE_LENGTH (code);
  int i;

  switch (TREE_CODE_CLASS (code))
    {
    case tcc_expression:
      switch (code)
	{
	case INIT_EXPR:
	case MODIFY_EXPR:
	case VA_ARG_EXPR:
	case PREDECREMENT_EXPR:
	case PREINCREMENT_EXPR:
	case POSTDECREMENT_EXPR:
	case POSTINCREMENT_EXPR:
	  /* All of these have side-effects, no matter what their
	     operands are.  */
	  return;

	default:
	  break;
	}
      /* Fall through.  */

    case tcc_comparison:  /* a comparison expression */
    case tcc_unary:       /* a unary arithmetic expression */
    case tcc_binary:      /* a binary arithmetic expression */
    case tcc_reference:   /* a reference */
      TREE_SIDE_EFFECTS (t) = TREE_THIS_VOLATILE (t);
      for (i = 0; i < len; ++i)
	{
	  tree op = TREE_OPERAND (t, i);
	  if (op && TREE_SIDE_EFFECTS (op))
	    TREE_SIDE_EFFECTS (t) = 1;
	}
      break;

    default:
      /* Can never be used with non-expressions.  */
      gcc_unreachable ();
   }
}

static void
append_stmt (tree stmt)
{
  if (!EXPR_HAS_LOCATION (stmt))
    SET_EXPR_LOCATION (stmt, input_location);
  TREE_SIDE_EFFECTS (stmt) = true;
  append_to_statement_list (stmt, &cur_stmts);
}

void 
tree_code_output_expression_statement (tree code, 
                                       unsigned char* filename, int lineno)
{
  /* Output the line number information.  */
  emit_line_note ((const char *)filename, lineno); 
  TREE_USED (code) = 1;
  TREE_SIDE_EFFECTS (code) = 1;
  expand_expr_stmt (code);
}

static bool
nonpure_call_p (tree stmt)
{
  tree call = get_call_expr_in (stmt);

  if (!call)
    return false;

  return TREE_SIDE_EFFECTS (call) != 0;
}

tree
convert_from_reference (tree val)
{
  if (TREE_CODE (TREE_TYPE (val)) == REFERENCE_TYPE)
    {
      tree t = canonical_type_variant (TREE_TYPE (TREE_TYPE (val)));
      tree ref = build1 (INDIRECT_REF, t, val);

       /* We *must* set TREE_READONLY when dereferencing a pointer to const,
	  so that we get the proper error message if the result is used
	  to assign to.  Also, &* is supposed to be a no-op.  */
      TREE_READONLY (ref) = CP_TYPE_CONST_P (t);
      TREE_THIS_VOLATILE (ref) = CP_TYPE_VOLATILE_P (t);
      TREE_SIDE_EFFECTS (ref)
	= (TREE_THIS_VOLATILE (ref) || TREE_SIDE_EFFECTS (val));
      REFERENCE_REF_P (ref) = 1;
      val = ref;
    }

  return val;
}

/* Callback for walk_stmt_load_store_ops.

   Return TRUE if OP will dereference the tree stored in DATA, FALSE
   otherwise.

   This routine only makes a superficial check for a dereference.  Thus,
   it must only be used if it is safe to return a false negative.  */
static bool
check_loadstore (gimple stmt, tree op, tree, void *data)
{
  if ((TREE_CODE (op) == MEM_REF || TREE_CODE (op) == TARGET_MEM_REF)
      && operand_equal_p (TREE_OPERAND (op, 0), (tree)data, 0))
    {
      TREE_THIS_VOLATILE (op) = 1;
      TREE_SIDE_EFFECTS (op) = 1;
      update_stmt (stmt);
      return true;
    }
  return false;
}

static void
gimplify_if_stmt (tree *stmt_p)
{
  tree stmt, cond, then_, else_;

  stmt = *stmt_p;
  cond = IF_COND (stmt);
  then_ = THEN_CLAUSE (stmt);
  else_ = ELSE_CLAUSE (stmt);

  if (!then_)
    then_ = build_empty_stmt ();
  if (!else_)
    else_ = build_empty_stmt ();

  if (integer_nonzerop (cond) && !TREE_SIDE_EFFECTS (else_))
    stmt = then_;
  else if (integer_zerop (cond) && !TREE_SIDE_EFFECTS (then_))
    stmt = else_;
  else
    stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_);
  *stmt_p = stmt;
}