gcc/c-semantics.c

   1 /* This file contains the definitions and documentation for the common
   2    tree codes used in the GNU C and C++ compilers (see c-common.def
   3    for the standard codes).
   4    Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
   5    Free Software Foundation, Inc.
   6    Written by Benjamin Chelf (chelf@codesourcery.com).
   7
   8 This file is part of GCC.
   9
  10 GCC is free software; you can redistribute it and/or modify it under
  11 the terms of the GNU General Public License as published by the Free
  12 Software Foundation; either version 2, or (at your option) any later
  13 version.
  14
  15 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18 for more details.
  19
  20 You should have received a copy of the GNU General Public License
  21 along with GCC; see the file COPYING.  If not, write to the Free
  22 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  23 02110-1301, USA.  */
  24
  25 #include "config.h"
  26 #include "system.h"
  27 #include "coretypes.h"
  28 #include "tm.h"
  29 #include "tree.h"
  30 #include "function.h"
  31 #include "splay-tree.h"
  32 #include "varray.h"
  33 #include "c-common.h"
  34 #include "except.h"
  35 /* In order for the format checking to accept the C frontend
  36    diagnostic framework extensions, you must define this token before
  37    including toplev.h.  */
  38 #define GCC_DIAG_STYLE __gcc_cdiag__
  39 #include "toplev.h"
  40 #include "flags.h"
  41 #include "ggc.h"
  42 #include "rtl.h"
  43 #include "output.h"
  44 #include "timevar.h"
  45 #include "predict.h"
  46 #include "tree-inline.h"
  47 #include "tree-gimple.h"
  48 #include "langhooks.h"
  49
  50 /* Create an empty statement tree rooted at T.  */
  51
  52 tree
  53 push_stmt_list (void)
  54 {
  55   tree t;
  56   t = alloc_stmt_list ();
  57   TREE_CHAIN (t) = cur_stmt_list;
  58   cur_stmt_list = t;
  59   return t;
  60 }
  61
  62 /* Finish the statement tree rooted at T.  */
  63
  64 tree
  65 pop_stmt_list (tree t)
  66 {
  67   tree u = cur_stmt_list, chain;
  68
  69   /* Pop statement lists until we reach the target level.  The extra
  70      nestings will be due to outstanding cleanups.  */
  71   while (1)
  72     {
  73       chain = TREE_CHAIN (u);
  74       TREE_CHAIN (u) = NULL_TREE;
  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 be the current source location.  */
 107 /* ??? This should be obsolete with the lineno_stmt productions
 108    in the grammar.  */
 109
 110 tree
 111 build_stmt (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, input_location);
 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 /* Let the back-end know about DECL.  */
 149
 150 void
 151 emit_local_var (tree decl)
 152 {
 153   /* Create RTL for this variable.  */
 154   if (!DECL_RTL_SET_P (decl))
 155     {
 156       if (DECL_HARD_REGISTER (decl))
 157         /* The user specified an assembler name for this variable.
 158            Set that up now.  */
 159         rest_of_decl_compilation (decl, 0, 0);
 160       else
 161         expand_decl (decl);
 162     }
 163 }
 164
 165 /* Create a CASE_LABEL_EXPR tree node and return it.  */
 166
 167 tree
 168 build_case_label (tree low_value, tree high_value, tree label_decl)
 169 {
 170   return build_stmt (CASE_LABEL_EXPR, low_value, high_value, label_decl);
 171 }