exception handling label patch

[Andrew Macleod <amacleod at cygnus dot com>]

I've just applied this patch to the EGCS sources. 

This removes the restriction which required exception handler labels
to be permanent rtl. A ripple effect was that all inlined labels
were forced to be permanent too, and this could end up using a lot
of memory, as Mark pointed out a while ago.   

This should solve that problem.

Andrew


	* except.h (struct handler_info): Add handler_number field
	* except.c (gen_exception_label): EH labels no longer need to be
	on the permanent obstack.
	(get_new_handler): Set the label number field.
	(output_exception_table_entry): Regenerate handler label reference 
	from the label number field.
	(init_eh): Remove a blank line
	* integrate.c (get_label_from_map): Labels no longer need to be
	on the permanent obstack.

Index: except.h
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/except.h,v
retrieving revision 1.25
diff -c -p -r1.25 except.h
*** except.h	1998/12/08 14:03:52	1.25
--- except.h	1998/12/08 22:25:45
*************** void set_exception_version_code         
*** 172,178 ****
  
  typedef struct handler_info 
  {
!   rtx  handler_label;
    void *type_info;
    struct handler_info *next;
  } handler_info;
--- 172,179 ----
  
  typedef struct handler_info 
  {
!   rtx handler_label;
!   int handler_number;
    void *type_info;
    struct handler_info *next;
  } handler_info;
Index: except.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/except.c,v
retrieving revision 1.73
diff -c -p -r1.73 except.c
*** except.c	1998/12/08 14:03:53	1.73
--- except.c	1998/12/08 22:25:48
*************** rtx
*** 616,626 ****
  gen_exception_label ()
  {
    rtx lab;
- 
-   push_obstacks_nochange ();
-   end_temporary_allocation ();
    lab = gen_label_rtx ();
-   pop_obstacks ();
    return lab;
  }
  
--- 616,622 ----
*************** get_new_handler (handler, typeinfo)
*** 924,929 ****
--- 920,926 ----
    struct handler_info* ptr;
    ptr = (struct handler_info *) malloc (sizeof (struct handler_info));
    ptr->handler_label = handler;
+   ptr->handler_number = CODE_LABEL_NUMBER (handler);
    ptr->type_info = typeinfo;
    ptr->next = NULL;
  
*************** output_exception_table_entry (file, n)
*** 2147,2154 ****
        if (handler == NULL)
          assemble_integer (GEN_INT (0), POINTER_SIZE / BITS_PER_UNIT, 1);
        else
!         assemble_integer (handler->handler_label, 
!                           POINTER_SIZE / BITS_PER_UNIT, 1);
  
        if (flag_new_exceptions)
          {
--- 2144,2154 ----
        if (handler == NULL)
          assemble_integer (GEN_INT (0), POINTER_SIZE / BITS_PER_UNIT, 1);
        else
!         {
!           ASM_GENERATE_INTERNAL_LABEL (buf, "L", handler->handler_number);
!           sym = gen_rtx_SYMBOL_REF (Pmode, buf);
!           assemble_integer (sym, POINTER_SIZE / BITS_PER_UNIT, 1);
!         }
  
        if (flag_new_exceptions)
          {
*************** check_exception_handler_labels ()
*** 2394,2400 ****
  void
  init_eh ()
  {
-   
    first_rethrow_symbol = create_rethrow_ref (0);
    final_rethrow = gen_exception_label ();
    last_rethrow_symbol = create_rethrow_ref (CODE_LABEL_NUMBER (final_rethrow));
--- 2394,2399 ----
Index: integrate.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/integrate.c,v
retrieving revision 1.40
diff -c -p -r1.40 integrate.c
*** integrate.c	1998/12/08 14:03:56	1.40
--- integrate.c	1998/12/08 22:25:52
*************** get_label_from_map (map, i)
*** 99,110 ****
    rtx x = map->label_map[i];
  
    if (x == NULL_RTX)
!     {                     
!       push_obstacks_nochange ();
!       end_temporary_allocation ();
!       x = map->label_map[i] = gen_label_rtx();
!       pop_obstacks ();
!     }
  
    return x;
  }
--- 99,105 ----
    rtx x = map->label_map[i];
  
    if (x == NULL_RTX)
!     x = map->label_map[i] = gen_label_rtx();
  
    return x;
  }