gcc/c-pragma.c

   1 /* Handle #pragma, system V.4 style.  Supports #pragma weak and #pragma pack.
   2    Copyright (C) 1992 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #include <stdio.h>
  22 #include "config.h"
  23 #include "tree.h"
  24 #include "except.h"
  25 #include "function.h"
  26 #include "defaults.h"
  27 #include "c-pragma.h"
  28
  29 #ifdef HANDLE_SYSV_PRAGMA
  30
  31 /* When structure field packing is in effect, this variable is the
  32    number of bits to use as the maximum alignment.  When packing is not
  33    in effect, this is zero.  */
  34
  35 extern int maximum_field_alignment;
  36
  37 /* File used for outputting assembler code.  */
  38 extern FILE *asm_out_file;
  39
  40 /* Handle one token of a pragma directive.  TOKEN is the
  41    current token, and STRING is its printable form.  */
  42
  43 void
  44 handle_pragma_token (string, token)
  45      char *string;
  46      tree token;
  47 {
  48   static enum pragma_state state = ps_start, type;
  49   static char *name;
  50   static char *value;
  51   static int align;
  52
  53   if (string == 0)
  54     {
  55       if (type == ps_pack)
  56         {
  57           if (state == ps_right)
  58             maximum_field_alignment = align * 8;
  59           else
  60             warning ("malformed `#pragma pack'");
  61         }
  62       else if (type == ps_weak)
  63         {
  64 #ifdef HANDLE_PRAGMA_WEAK
  65           if (HANDLE_PRAGMA_WEAK)
  66             handle_pragma_weak (state, name, value);
  67
  68 #endif /* HANDLE_PRAMA_WEAK */
  69         }
  70
  71       type = state = ps_start;
  72       return;
  73     }
  74
  75   switch (state)
  76     {
  77     case ps_start:
  78       if (token && TREE_CODE (token) == IDENTIFIER_NODE)
  79         {
  80           if (strcmp (IDENTIFIER_POINTER (token), "pack") == 0)
  81             type = state = ps_pack;
  82           else if (strcmp (IDENTIFIER_POINTER (token), "weak") == 0)
  83             type = state = ps_weak;
  84           else
  85             type = state = ps_done;
  86         }
  87       else
  88         type = state = ps_done;
  89       break;
  90
  91     case ps_weak:
  92       if (token && TREE_CODE (token) == IDENTIFIER_NODE)
  93         {
  94           name = IDENTIFIER_POINTER (token);
  95           state = ps_name;
  96         }
  97       else
  98         state = ps_bad;
  99       break;
 100
 101     case ps_name:
 102       state = (strcmp (string, "=") ? ps_bad : ps_equals);
 103       break;
 104
 105     case ps_equals:
 106       if (token && TREE_CODE (token) == IDENTIFIER_NODE)
 107         {
 108           value = IDENTIFIER_POINTER (token);
 109           state = ps_value;
 110         }
 111       else
 112         state = ps_bad;
 113       break;
 114
 115     case ps_value:
 116       state = ps_bad;
 117       break;
 118
 119     case ps_pack:
 120       if (strcmp (string, "(") == 0)
 121         state = ps_left;
 122       else
 123         state = ps_bad;
 124       break;
 125
 126     case ps_left:
 127       if (token && TREE_CODE (token) == INTEGER_CST
 128           && TREE_INT_CST_HIGH (token) == 0)
 129         switch (TREE_INT_CST_LOW (token))
 130           {
 131           case 1:
 132           case 2:
 133           case 4:
 134             align = TREE_INT_CST_LOW (token);
 135             state = ps_align;
 136             break;
 137
 138           default:
 139             state = ps_bad;
 140           }
 141       else if (! token && strcmp (string, ")") == 0)
 142         {
 143           align = 0;
 144           state = ps_right;
 145         }
 146       else
 147         state = ps_bad;
 148       break;
 149
 150     case ps_align:
 151       if (strcmp (string, ")") == 0)
 152         state = ps_right;
 153       else
 154         state = ps_bad;
 155       break;
 156
 157     case ps_right:
 158       state = ps_bad;
 159       break;
 160
 161     case ps_bad:
 162     case ps_done:
 163       break;
 164
 165     default:
 166       abort ();
 167     }
 168 }
 169 #endif /* HANDLE_SYSV_PRAGMA */