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