gcc/libchill/exh.c

/* Implement runtime actions for CHILL.
   Copyright (C) 1992,1993 Free Software Foundation, Inc.
   Author: Wilfried Moser

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, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#define __CHILL_LIB__

#include <stdio.h>
#include <setjmp.h>
#include "rtltypes.h"

extern void cause_exception (char *exname, char *file, int lineno, int user_arg);
extern void unhandled_exception (char *exname, char *file, int lineno, int user_arg);

/* An action with a handler:
	BODY ON (e1, e2): H12; (e3): H3; ELSE HE; END;
   is translated into:

    struct __ch_handler __tmp;
    static struct __ch_handler_excepts _H[4] =
      {
        { <<e1>>, 1 },
        { <<e2>>, 1 },
        { <<e3>>, 2 },
        { __ch_else_except, 3 },
      };
    __ch_link_handler(&__tmp);
    __tmp.handlers = _H;
    switch (setmp(&__tmp.jbuf))
      {	
      case 0:  BODY; __ch_unlink_handler(&__tmp); break;
      case 1:  H12; break;
      case 2:  H3; break;
      case 3:  HE; break;
      }
*/

/* this part contains all neccessary functions to handle exceptions in CHILL */

/* These two trivial function aren't inlines, to allow for
   more flexibility (e.g. a per-thread exception stack). */

extern void __setexceptionStack (TExceptionHandlerStack *new);
extern TExceptionHandlerStack * __getexceptionStack (void);

void
__ch_link_handler (handler)
     struct __ch_handler *handler;
{
  handler->prev = __getexceptionStack ();
  __setexceptionStack (handler);
}

 void
__ch_unlink_handler (handler)
     struct __ch_handler *handler;
{
  __setexceptionStack (handler->prev);
}

/*
 * function __cause_exception
 *
 * parameters:
 *  exnum		name string of exception to raise
 *  file		filename of CAUSE statement
 *  lineno		linenumber of CAUSE statement
 *  user_arg		user specified argument
 *
 * returns:
 *  never		leave function with longjmp or abort
 *
 * abstract:
 *  search exceptionstack for last handler of caused exception,
 *  call userdefined function to signal exception,
 *  jump to handler with longjmp or call unhandled_exception
 *
 */

void
__cause_exception  (ex, file, lineno, user_arg)
     char *ex;
     char *file;
     int  lineno;
     int user_arg;
{
  register struct __ch_handler *handler = __getexceptionStack();

  /* call user defined cause function */
  cause_exception (ex, file, lineno, user_arg);
  
  for ( ; handler != NULL; handler = handler->prev)
    {
      register struct __ch_handled_excepts *list = handler->handlers;
      for ( ; list->code != 0; list++ )
	{
	  if (list->ex == __ch_else_except || EX_EQ(list->ex, ex)) /* found */
	    {
	      __setexceptionStack (handler->prev);
	      longjmp(handler->jbuf, list->code);	  
	    }
	}
    }

  /* no handler found -- call unhandled_exception */
  unhandled_exception (ex, file, lineno, user_arg);
  abort ();
}

/*
 * function __cause_ex1
 *
 * parameters:
 *  exnum		name string of exception to raise
 *  file		filename of CAUSE statement
 *  lineno		linenumber of CAUSE statement
 *
 * returns:
 *  never		leave function with longjmp or abort
 *
 * abstract:
 *  This is the function the compiler generated code calls.
 *  Search exceptionstack for last handler of caused exception,
 *  call userdefined function to signal exception,
 *  jump to handler with longjmp or call unhandled_exception
 *
 */

void
__cause_ex1  (ex, file, lineno)
     char *ex;
     char *file;
     int  lineno;
{
  __cause_exception (ex, file, lineno, 0);
}