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