source: trunk/third/gcc/c-pragma.c @ 8834

/* Handle #pragma, system V.4 style.  Supports #pragma weak and #pragma pack.
   Copyright (C) 1992 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include <stdio.h>
#include "config.h"
#include "tree.h"
#include "function.h"
#include "defaults.h"
#include "c-pragma.h"

#ifdef HANDLE_SYSV_PRAGMA

/* When structure field packing is in effect, this variable is the
   number of bits to use as the maximum alignment.  When packing is not
   in effect, this is zero. */

extern int maximum_field_alignment;

/* File used for outputting assembler code.  */
extern FILE *asm_out_file;

/* Handle one token of a pragma directive.  TOKEN is the
   current token, and STRING is its printable form.  */

void
handle_pragma_token (string, token)
     char *string;
     tree token;
{
  static enum pragma_state state = ps_start, type;
  static char *name;
  static char *value;
  static int align;

  if (string == 0)
    {
      if (type == ps_pack)
        {
          if (state == ps_right)
            maximum_field_alignment = align * 8;
          else
            warning ("malformed `#pragma pack'");
        }
      else if (type == ps_weak)
        {
#ifdef HANDLE_PRAGMA_WEAK
          if (HANDLE_PRAGMA_WEAK)
            handle_pragma_weak (state, name, value);

#endif /* HANDLE_PRAMA_WEAK */
        }

      type = state = ps_start;
      return;
    }

  switch (state)
    {
    case ps_start:
      if (token && TREE_CODE (token) == IDENTIFIER_NODE)
        {
          if (strcmp (IDENTIFIER_POINTER (token), "pack") == 0)
            type = state = ps_pack;
          else if (strcmp (IDENTIFIER_POINTER (token), "weak") == 0)
            type = state = ps_weak;
          else
            type = state = ps_done;
        }
      else
        type = state = ps_done;
      break;

    case ps_weak:
      if (token && TREE_CODE (token) == IDENTIFIER_NODE)
        {
          name = IDENTIFIER_POINTER (token);
          state = ps_name;
        }
      else
        state = ps_bad;
      break;

    case ps_name:
      state = (strcmp (string, "=") ? ps_bad : ps_equals);
      break;

    case ps_equals:
      if (token && TREE_CODE (token) == IDENTIFIER_NODE)
        {
          value = IDENTIFIER_POINTER (token);
          state = ps_value;
        }
      else
        state = ps_bad;
      break;

    case ps_value:
      state = ps_bad;
      break;

    case ps_pack:
      if (strcmp (string, "(") == 0)
        state = ps_left;
      else
        state = ps_bad;
      break;

    case ps_left:
      if (token && TREE_CODE (token) == INTEGER_CST
          && TREE_INT_CST_HIGH (token) == 0)
        switch (TREE_INT_CST_LOW (token))
          {
          case 1:
          case 2:
          case 4:
            align = TREE_INT_CST_LOW (token);
            state = ps_align;
            break;

          default:
            state = ps_bad;
          }
      else if (! token && strcmp (string, ")") == 0)
        {
          align = 0;
          state = ps_right;
        }
      else
        state = ps_bad;
      break;

    case ps_align:
      if (strcmp (string, ")") == 0)
        state = ps_right;
      else
        state = ps_bad;
      break;

    case ps_right:
      state = ps_bad;
      break;

    case ps_bad:
    case ps_done:
      break;

    default:
      abort ();
    }
}
#endif /* HANDLE_SYSV_PRAGMA */