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, 2007
   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 3, 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 COPYING3.  If not see
  22 <http://www.gnu.org/licenses/>.  */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "tm.h"
  28 #include "tree.h"
  29 #include "function.h"
  30 #include "splay-tree.h"
  31 #include "varray.h"
  32 #include "c-common.h"
  33 #include "except.h"
  34 /* In order for the format checking to accept the C frontend
  35    diagnostic framework extensions, you must define this token before
  36    including toplev.h.  */
  37 #define GCC_DIAG_STYLE __gcc_cdiag__
  38 #include "toplev.h"
  39 #include "flags.h"
  40 #include "ggc.h"
  41 #include "rtl.h"
  42 #include "output.h"
  43 #include "timevar.h"
  44 #include "predict.h"
  45 #include "tree-inline.h"
  46 #include "tree-gimple.h"
  47 #include "langhooks.h"
  48
  49 /* Create an empty statement tree rooted at T.  */
  50
  51 tree
  52 push_stmt_list (void)
  53 {
  54   tree t;
  55   t = alloc_stmt_list ();
  56   TREE_CHAIN (t) = cur_stmt_list;
  57   cur_stmt_list = t;
  58   return t;
  59 }
  60
  61 /* Finish the statement tree rooted at T.  */
  62
  63 tree
  64 pop_stmt_list (tree t)
  65 {
  66   tree u = cur_stmt_list, chain;
  67
  68   /* Pop statement lists until we reach the target level.  The extra
  69      nestings will be due to outstanding cleanups.  */
  70   while (1)
  71     {
  72       chain = TREE_CHAIN (u);
  73       TREE_CHAIN (u) = NULL_TREE;
  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 be the current source location.  */
 106 /* ??? This should be obsolete with the lineno_stmt productions
 107    in the grammar.  */
 108
 109 tree
 110 build_stmt (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, input_location);
 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 /* Let the back-end know about DECL.  */
 148
 149 void
 150 emit_local_var (tree decl)
 151 {
 152   /* Create RTL for this variable.  */
 153   if (!DECL_RTL_SET_P (decl))
 154     {
 155       if (DECL_HARD_REGISTER (decl))
 156         /* The user specified an assembler name for this variable.
 157            Set that up now.  */
 158         rest_of_decl_compilation (decl, 0, 0);
 159       else
 160         expand_decl (decl);
 161     }
 162 }
 163
 164 /* Create a CASE_LABEL_EXPR tree node and return it.  */
 165
 166 tree
 167 build_case_label (tree low_value, tree high_value, tree label_decl)
 168 {
 169   return build_stmt (CASE_LABEL_EXPR, low_value, high_value, label_decl);
 170 }