gcc/c-family/c-semantics.c

   1 /* This file contains subroutine used by the C front-end to construct GENERIC.
   2    Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Written by Benjamin Chelf (chelf@codesourcery.com).
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "function.h"
  28 #include "splay-tree.h"
  29 #include "c-common.h"
  30 #include "flags.h"
  31 #include "tree-iterator.h"
  32
  33 /* Create an empty statement tree rooted at T.  */
  34
  35 tree
  36 push_stmt_list (void)
  37 {
  38   tree t;
  39   t = alloc_stmt_list ();
  40   VEC_safe_push (tree, gc, stmt_list_stack, t);
  41   return t;
  42 }
  43
  44 /* Finish the statement tree rooted at T.  */
  45
  46 tree
  47 pop_stmt_list (tree t)
  48 {
  49   tree u = NULL_TREE;
  50
  51   /* Pop statement lists until we reach the target level.  The extra
  52      nestings will be due to outstanding cleanups.  */
  53   while (1)
  54     {
  55       u = VEC_pop (tree, stmt_list_stack);
  56       if (!VEC_empty (tree, stmt_list_stack))
  57         {
  58           tree x = VEC_last (tree, stmt_list_stack);
  59           STATEMENT_LIST_HAS_LABEL (x) |= STATEMENT_LIST_HAS_LABEL (u);
  60         }
  61       if (t == u)
  62         break;
  63     }
  64
  65   gcc_assert (u != NULL_TREE);
  66
  67   /* If the statement list is completely empty, just return it.  This is
  68      just as good small as build_empty_stmt, with the advantage that
  69      statement lists are merged when they appended to one another.  So
  70      using the STATEMENT_LIST avoids pathological buildup of EMPTY_STMT_P
  71      statements.  */
  72   if (TREE_SIDE_EFFECTS (t))
  73     {
  74       tree_stmt_iterator i = tsi_start (t);
  75
  76       /* If the statement list contained exactly one statement, then
  77          extract it immediately.  */
  78       if (tsi_one_before_end_p (i))
  79         {
  80           u = tsi_stmt (i);
  81           tsi_delink (&i);
  82           free_stmt_list (t);
  83           t = u;
  84         }
  85     }
  86
  87   return t;
  88 }
  89
  90 /* Build a generic statement based on the given type of node and
  91    arguments. Similar to `build_nt', except that we set
  92    EXPR_LOCATION to LOC. */
  93 /* ??? This should be obsolete with the lineno_stmt productions
  94    in the grammar.  */
  95
  96 tree
  97 build_stmt (location_t loc, enum tree_code code, ...)
  98 {
  99   tree ret;
 100   int length, i;
 101   va_list p;
 102   bool side_effects;
 103
 104   /* This function cannot be used to construct variably-sized nodes.  */
 105   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
 106
 107   va_start (p, code);
 108
 109   ret = make_node (code);
 110   TREE_TYPE (ret) = void_type_node;
 111   length = TREE_CODE_LENGTH (code);
 112   SET_EXPR_LOCATION (ret, loc);
 113
 114   /* TREE_SIDE_EFFECTS will already be set for statements with
 115      implicit side effects.  Here we make sure it is set for other
 116      expressions by checking whether the parameters have side
 117      effects.  */
 118
 119   side_effects = false;
 120   for (i = 0; i < length; i++)
 121     {
 122       tree t = va_arg (p, tree);
 123       if (t && !TYPE_P (t))
 124         side_effects |= TREE_SIDE_EFFECTS (t);
 125       TREE_OPERAND (ret, i) = t;
 126     }
 127
 128   TREE_SIDE_EFFECTS (ret) |= side_effects;
 129
 130   va_end (p);
 131   return ret;
 132 }
 133
 134 /* Build a REALPART_EXPR or IMAGPART_EXPR, according to CODE, from ARG.  */
 135
 136 tree
 137 build_real_imag_expr (location_t location, enum tree_code code, tree arg)
 138 {
 139   tree ret;
 140   tree arg_type = TREE_TYPE (arg);
 141
 142   gcc_assert (code == REALPART_EXPR || code == IMAGPART_EXPR);
 143
 144   if (TREE_CODE (arg_type) == COMPLEX_TYPE)
 145     {
 146       ret = build1 (code, TREE_TYPE (TREE_TYPE (arg)), arg);
 147       SET_EXPR_LOCATION (ret, location);
 148     }
 149   else if (INTEGRAL_TYPE_P (arg_type) || SCALAR_FLOAT_TYPE_P (arg_type))
 150     {
 151       ret = (code == REALPART_EXPR
 152              ? arg
 153              : omit_one_operand_loc (location, arg_type,
 154                                      integer_zero_node, arg));
 155     }
 156   else
 157     {
 158       error_at (location, "wrong type argument to %s",
 159                 code == REALPART_EXPR ? "__real" : "__imag");
 160       ret = error_mark_node;
 161     }
 162
 163   return ret;
 164 }