gcc/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
   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 "varray.h"
  30 #include "c-common.h"
  31 #include "except.h"
  32 /* In order for the format checking to accept the C frontend
  33    diagnostic framework extensions, you must define this token before
  34    including toplev.h.  */
  35 #define GCC_DIAG_STYLE __gcc_cdiag__
  36 #include "toplev.h"
  37 #include "flags.h"
  38 #include "ggc.h"
  39 #include "rtl.h"
  40 #include "output.h"
  41 #include "timevar.h"
  42 #include "predict.h"
  43 #include "tree-inline.h"
  44 #include "gimple.h"
  45 #include "tree-iterator.h"
  46 #include "langhooks.h"
  47
  48 /* Create an empty statement tree rooted at T.  */
  49
  50 tree
  51 push_stmt_list (void)
  52 {
  53   tree t;
  54   t = alloc_stmt_list ();
  55   TREE_CHAIN (t) = cur_stmt_list;
  56   cur_stmt_list = t;
  57   return t;
  58 }
  59
  60 /* Finish the statement tree rooted at T.  */
  61
  62 tree
  63 pop_stmt_list (tree t)
  64 {
  65   tree u = cur_stmt_list, chain;
  66
  67   /* Pop statement lists until we reach the target level.  The extra
  68      nestings will be due to outstanding cleanups.  */
  69   while (1)
  70     {
  71       chain = TREE_CHAIN (u);
  72       TREE_CHAIN (u) = NULL_TREE;
  73       if (chain)
  74         STATEMENT_LIST_HAS_LABEL (chain) |= STATEMENT_LIST_HAS_LABEL (u);
  75       if (t == u)
  76         break;
  77       u = chain;
  78     }
  79   cur_stmt_list = chain;
  80
  81   /* If the statement list is completely empty, just return it.  This is
  82      just as good small as build_empty_stmt, with the advantage that
  83      statement lists are merged when they appended to one another.  So
  84      using the STATEMENT_LIST avoids pathological buildup of EMPTY_STMT_P
  85      statements.  */
  86   if (TREE_SIDE_EFFECTS (t))
  87     {
  88       tree_stmt_iterator i = tsi_start (t);
  89
  90       /* If the statement list contained exactly one statement, then
  91          extract it immediately.  */
  92       if (tsi_one_before_end_p (i))
  93         {
  94           u = tsi_stmt (i);
  95           tsi_delink (&i);
  96           free_stmt_list (t);
  97           t = u;
  98         }
  99     }
 100
 101   return t;
 102 }
 103
 104 /* Build a generic statement based on the given type of node and
 105    arguments. Similar to `build_nt', except that we set
 106    EXPR_LOCATION to LOC. */
 107 /* ??? This should be obsolete with the lineno_stmt productions
 108    in the grammar.  */
 109
 110 tree
 111 build_stmt (location_t loc, enum tree_code code, ...)
 112 {
 113   tree ret;
 114   int length, i;
 115   va_list p;
 116   bool side_effects;
 117
 118   /* This function cannot be used to construct variably-sized nodes.  */
 119   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
 120
 121   va_start (p, code);
 122
 123   ret = make_node (code);
 124   TREE_TYPE (ret) = void_type_node;
 125   length = TREE_CODE_LENGTH (code);
 126   SET_EXPR_LOCATION (ret, loc);
 127
 128   /* TREE_SIDE_EFFECTS will already be set for statements with
 129      implicit side effects.  Here we make sure it is set for other
 130      expressions by checking whether the parameters have side
 131      effects.  */
 132
 133   side_effects = false;
 134   for (i = 0; i < length; i++)
 135     {
 136       tree t = va_arg (p, tree);
 137       if (t && !TYPE_P (t))
 138         side_effects |= TREE_SIDE_EFFECTS (t);
 139       TREE_OPERAND (ret, i) = t;
 140     }
 141
 142   TREE_SIDE_EFFECTS (ret) |= side_effects;
 143
 144   va_end (p);
 145   return ret;
 146 }
 147
 148 /* Create a CASE_LABEL_EXPR tree node and return it.  */
 149
 150 tree
 151 build_case_label (location_t loc,
 152                   tree low_value, tree high_value, tree label_decl)
 153 {
 154   return build_stmt (loc, CASE_LABEL_EXPR, low_value, high_value, label_decl);
 155 }