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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include <stdio.h>
  21 #include "config.h"
  22 #include "tree.h"
  23 #include "function.h"
  24 #include "defaults.h"
  25 #include "c-pragma.h"
  26
  27 #ifdef HANDLE_SYSV_PRAGMA
  28
  29 /* When structure field packing is in effect, this variable is the
  30    number of bits to use as the maximum alignment.  When packing is not
  31    in effect, this is zero. */
  32
  33 extern int maximum_field_alignment;
  34
  35 /* File used for outputting assembler code.  */
  36 extern FILE *asm_out_file;
  37
  38 /* Handle one token of a pragma directive.  TOKEN is the
  39    current token, and STRING is its printable form.  */
  40
  41 void
  42 handle_pragma_token (string, token)
  43      char *string;
  44      tree token;
  45 {
  46   static enum pragma_state state = ps_start, type;
  47   static char *name;
  48   static char *value;
  49   static int align;
  50
  51   if (string == 0)
  52     {
  53       if (type == ps_pack)
  54         {
  55           if (state == ps_right)
  56             maximum_field_alignment = align * 8;
  57           else
  58             warning ("malformed `#pragma pack'");
  59         }
  60       else if (type == ps_weak)
  61         {
  62 #ifdef HANDLE_PRAGMA_WEAK
  63           if (HANDLE_PRAGMA_WEAK)
  64             handle_pragma_weak (state, name, value);
  65
  66 #endif /* HANDLE_PRAMA_WEAK */
  67         }
  68
  69       type = state = ps_start;
  70       return;
  71     }
  72
  73   switch (state)
  74     {
  75     case ps_start:
  76       if (token && TREE_CODE (token) == IDENTIFIER_NODE)
  77         {
  78           if (strcmp (IDENTIFIER_POINTER (token), "pack") == 0)
  79             type = state = ps_pack;
  80           else if (strcmp (IDENTIFIER_POINTER (token), "weak") == 0)
  81             type = state = ps_weak;
  82           else
  83             type = state = ps_done;
  84         }
  85       else
  86         type = state = ps_done;
  87       break;
  88
  89     case ps_weak:
  90       if (token && TREE_CODE (token) == IDENTIFIER_NODE)
  91         {
  92           name = IDENTIFIER_POINTER (token);
  93           state = ps_name;
  94         }
  95       else
  96         state = ps_bad;
  97       break;
  98
  99     case ps_name:
 100       state = (strcmp (string, "=") ? ps_bad : ps_equals);
 101       break;
 102
 103     case ps_equals:
 104       if (token && TREE_CODE (token) == IDENTIFIER_NODE)
 105         {
 106           value = IDENTIFIER_POINTER (token);
 107           state = ps_value;
 108         }
 109       else
 110         state = ps_bad;
 111       break;
 112
 113     case ps_value:
 114       state = ps_bad;
 115       break;
 116
 117     case ps_pack:
 118       if (strcmp (string, "(") == 0)
 119         state = ps_left;
 120       else
 121         state = ps_bad;
 122       break;
 123
 124     case ps_left:
 125       if (token && TREE_CODE (token) == INTEGER_CST
 126           && TREE_INT_CST_HIGH (token) == 0)
 127         switch (TREE_INT_CST_LOW (token))
 128           {
 129           case 1:
 130           case 2:
 131           case 4:
 132             align = TREE_INT_CST_LOW (token);
 133             state = ps_align;
 134             break;
 135
 136           default:
 137             state = ps_bad;
 138           }
 139       else if (! token && strcmp (string, ")") == 0)
 140         {
 141           align = 0;
 142           state = ps_right;
 143         }
 144       else
 145         state = ps_bad;
 146       break;
 147
 148     case ps_align:
 149       if (strcmp (string, ")") == 0)
 150         state = ps_right;
 151       else
 152         state = ps_bad;
 153       break;
 154
 155     case ps_right:
 156       state = ps_bad;
 157       break;
 158
 159     case ps_bad:
 160     case ps_done:
 161       break;
 162
 163     default:
 164       abort ();
 165     }
 166 }
 167 #endif /* HANDLE_SYSV_PRAGMA */