1 /* Exception support for GNU CHILL.
2 WARNING: Only works for native (needs setjmp.h)! FIXME!
3 Copyright (C) 1992, 93, 1994 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
26 /* On Suns this can get you to the right definition if you
27 set the right value for TARGET. */
30 /* Can you believe they forgot this? */
37 #define _JBLEN (sizeof(jmp_buf)/sizeof(int))
38 #define _JBLEN_2 _JBLEN+20
40 /* if we use i.e. posix threads, this buffer must be longer */
41 #define _JBLEN_2 _JBLEN+20
44 /* On Linux setjmp is __setjmp FIXME: what is for CROSS */
45 #ifndef SETJMP_LIBRARY_NAME
47 #define SETJMP_LIBRARY_NAME "__setjmp"
49 #define SETJMP_LIBRARY_NAME "setjmp"
53 extern int expand_exit_needed;
54 extern tree build_chill_exception_decl PROTO((char *));
55 extern void chill_handle_case_default PROTO((void));
56 extern void emit_jump PROTO((rtx));
57 extern void expand_decl PROTO((tree));
58 extern void fatal PROTO((char *, ...));
59 extern void make_decl_rtl PROTO((tree, char *, int));
60 extern void rest_of_decl_compilation PROTO((tree, char *, int, int));
62 static tree link_handler_decl;
63 static tree handler_link_pointer_type;
64 static tree unlink_handler_decl;
65 static int exceptions_initialized = 0;
66 static void emit_setup_handler PROTO((void));
67 static void initialize_exceptions PROTO((void));
68 static tree char_pointer_type_for_handler;
70 /* If this is 1, operations to push and pop on the __exceptionStack
71 are inline. The default is is to use a function call, to
72 allow for a per-thread exception stack. */
73 static int inline_exception_stack_ops = 0;
77 struct handler_state *next;
79 /* Starts at 0, then incremented for every <on-alternative>. */
80 int prev_on_alternative;
82 /* If > 0: handler number for ELSE handler. */
92 /* A decl for the static handler array (used to map exception name to int).*/
93 tree handler_array_decl;
97 /* Used to pass a tree from emit_setup_handler to chill_start_on. */
104 /* flag to indicate that we are currently compiling this handler.
105 is_handled will need this to determine an unhandled exception */
109 /* This is incremented by one each time we start an action which
110 might have an ON-handler. It is reset between passes. */
111 static int action_number = 0;
113 int action_nesting_level = 0;
115 /* The global_handler_list is constructed in pass 1. It is not sorted.
116 It contains one element for each action that actually had an ON-handler.
117 An element's ACTION_NUMBER matches the action_number
118 of that action. The global_handler_list is eaten up during pass 2. */
119 #define ACTION_NUMBER(HANDLER) ((HANDLER)->action_number)
120 struct handler_state *global_handler_list = NULL;
122 /* This is a stack of handlers, one for each nested ON-handler. */
123 static struct handler_state *current_handler = NULL;
125 static struct handler_state *free_handlers = NULL; /* freelist */
127 static tree handler_element_type;
128 static tree handler_link_type;
130 static tree jbuf_ident, prev_ident, handlers_ident;
131 static tree exception_stack_decl = 0;
133 /* Chain of cleanups assocated with exception handlers.
134 The TREE_PURPOSE is an INTEGER_CST whose value is the
135 DECL_ACTION_NESTING_LEVEL (when the handled actions was entered).
136 The TREE_VALUE is an expression to expand when we exit that action. */
138 static tree cleanup_chain = NULL_TREE;
141 /* Merge the current sequence onto the tail of the previous one. */
146 rtx sequence_first = get_insns ();
149 emit_insns (sequence_first);
154 /* Things we need to do at the beginning of pass 2. */
157 except_init_pass_2 ()
159 /* First sort the global_handler_list on ACTION_NUMBER.
160 This will already be in close to reverse order (the exception being
161 nested ON-handlers), so insertion sort should essentially linear. */
163 register struct handler_state *old_list = global_handler_list;
165 /* First add a dummy final element. */
167 global_handler_list = free_handlers;
170 = (struct handler_state*) permalloc (sizeof (struct handler_state));
171 /* Make the final dummy "larger" than any other element. */
172 ACTION_NUMBER (global_handler_list) = action_number + 1;
173 /* Now move all the elements in old_list over to global_handler_list. */
174 while (old_list != NULL)
176 register struct handler_state **ptr = &global_handler_list;
177 /* Unlink from old_list. */
178 register struct handler_state *current = old_list;
179 old_list = old_list->next;
181 while (ACTION_NUMBER (current) > ACTION_NUMBER (*ptr))
183 /* Link into proper place in global_handler_list (new list). */
184 current->next = *ptr;
188 /* Don't forget to reset action_number. */
192 /* This function is called at the beginning of an action that might be
193 followed by an ON-handler. Chill syntax doesn't let us know if
194 we actually have an ON-handler until we see the ON, so we save
195 away during pass 1 that information for use during pass 2. */
200 register struct handler_state *hstate;
203 action_nesting_level++;
209 hstate = free_handlers;
210 free_handlers = hstate->next;
215 (struct handler_state*) permalloc (sizeof (struct handler_state));
218 hstate->next = current_handler;
219 current_handler = hstate;
220 hstate->prev_on_alternative = 0;
221 hstate->else_handler = 0;
222 hstate->on_alt_list = NULL_TREE;
223 hstate->compiling = 0;
225 ACTION_NUMBER (hstate) = action_number;
229 if (ACTION_NUMBER (global_handler_list) != action_number)
232 /* OK. This action actually has an ON-handler.
233 Pop it from global_handler_list, and use it. */
235 hstate = global_handler_list;
236 global_handler_list = hstate->next;
238 /* Since this is pass 2, let's generate prologue code for that. */
240 hstate->next = current_handler;
241 current_handler = hstate;
243 hstate->prev_on_alternative = 0;
244 hstate->function = current_function_decl;
246 emit_setup_handler ();
250 start_handler_array ()
252 tree handler_array_type, decl;
254 push_obstacks_nochange ();
255 end_temporary_allocation ();
256 handler_array_type = build_array_type (handler_element_type, NULL_TREE);
257 decl = build_lang_decl (VAR_DECL,
258 get_unique_identifier ("handler_table"),
261 /* TREE_TYPE (decl) = handler_array_type;*/
262 TREE_READONLY (decl) = 1;
263 TREE_STATIC (decl) = 1;
264 DECL_INITIAL (decl) = error_mark_node;
267 make_decl_rtl (decl, NULL_PTR, 0);
268 current_handler->handler_array_decl = decl;
273 finish_handler_array ()
275 tree decl = current_handler->handler_array_decl;
277 tree handler_array_init = NULL_TREE;
278 int handlers_count = 1;
281 /* Build the table mapping exceptions to handler(-number)s.
282 This is done in reverse order. */
284 /* First push the end of the list. This is either the ELSE
285 handler (current_handler->else_handler>0) or NULL handler to indicate
286 the end of the list (if current_handler->else-handler == 0).
287 The following works either way. */
288 handler_array_init = build_tree_list
289 (NULL_TREE, chill_expand_tuple
290 (handler_element_type,
291 build_nt (CONSTRUCTOR, NULL_TREE,
292 tree_cons (NULL_TREE,
294 build_tree_list (NULL_TREE,
295 build_int_2 (current_handler->else_handler,
298 for (t = current_handler->on_alt_list; t != NULL_TREE; t = TREE_CHAIN (t))
299 { tree handler_number = TREE_PURPOSE(t);
300 tree elist = TREE_VALUE (t);
301 for ( ; elist != NULL_TREE; elist = TREE_CHAIN (elist))
304 build_chill_exception_decl (IDENTIFIER_POINTER(TREE_VALUE(elist)));
305 tree ex_addr = build1 (ADDR_EXPR,
306 char_pointer_type_for_handler,
308 tree el = build_nt (CONSTRUCTOR, NULL_TREE,
309 tree_cons (NULL_TREE,
311 build_tree_list (NULL_TREE,
313 mark_addressable (ex_decl);
314 TREE_CONSTANT (ex_addr) = 1;
316 tree_cons (NULL_TREE,
317 chill_expand_tuple (handler_element_type, el),
324 nelts = list_length (handler_array_init);
325 TYPE_DOMAIN (TREE_TYPE (decl))
326 = build_index_type (build_int_2 (nelts - 1, - (nelts == 0)));
327 layout_type (TREE_TYPE (decl));
329 = convert (TREE_TYPE (decl),
330 build_nt (CONSTRUCTOR, NULL_TREE, handler_array_init));
332 /* Pop back to the obstack that is current for this binding level.
333 This is because MAXINDEX, rtl, etc. to be made below
334 must go in the permanent obstack. But don't discard the
335 temporary data yet. */
337 layout_decl (decl, 0);
338 /* To prevent make_decl_rtl (called indiectly by rest_of_decl_compilation)
339 throwing the existing RTL (which has already been used). */
340 PUT_MODE (DECL_RTL (decl), DECL_MODE (decl));
341 rest_of_decl_compilation (decl, (char*)0, 0, 0);
342 expand_decl_init (decl);
344 /* To prevent make_decl_rtl (called indirectly by finish_decl)
345 altering the existing RTL. */
346 GET_MODE (DECL_RTL (current_handler->handler_array_decl)) =
347 DECL_MODE (current_handler->handler_array_decl);
349 finish_decl (current_handler->handler_array_decl,
350 build_nt (CONSTRUCTOR, NULL_TREE, handler_array_init),
360 action_nesting_level--;
363 struct handler_state *old = current_handler;
365 fatal ("internal error: on stack out of sync");
366 current_handler = old->next;
369 { /* Push unto global_handler_list. */
370 old->next = global_handler_list;
371 global_handler_list = old;
375 /* Push onto free_handlers free list. */
376 old->next = free_handlers;
382 current_handler = current_handler->next;
386 /* Emit code before an action that has an ON-handler. */
389 emit_setup_handler ()
391 tree handler_decl, handler_addr, t;
393 /* Field references. */
394 tree jbuf_ref, handlers_ref,prev_ref;
395 if (!exceptions_initialized)
397 /* We temporarily reset the maximum_field_alignment to zero so the
398 compiler's exception data structures can be compatible with the
399 run-time system, even when we're compiling with -fpack. */
400 extern int maximum_field_alignment;
401 int save_maximum_field_alignment = maximum_field_alignment;
402 maximum_field_alignment = 0;
403 push_obstacks_nochange ();
404 end_temporary_allocation ();
405 initialize_exceptions ();
407 maximum_field_alignment = save_maximum_field_alignment;
412 handler_decl = build_lang_decl (VAR_DECL,
413 get_unique_identifier ("handler"),
415 push_obstacks_nochange ();
416 pushdecl(handler_decl);
417 expand_decl (handler_decl);
418 finish_decl (handler_decl);
420 jbuf_ref = build_component_ref (handler_decl, jbuf_ident);
421 jbuf_ref = build_chill_arrow_expr (jbuf_ref, 1);
422 handlers_ref = build_component_ref (handler_decl, handlers_ident);
423 prev_ref = build_component_ref (handler_decl, prev_ident);
425 /* Emit code to link in handler in __exceptionStack chain. */
426 mark_addressable (handler_decl);
427 handler_addr = build1 (ADDR_EXPR, handler_link_pointer_type, handler_decl);
428 if (inline_exception_stack_ops)
430 expand_expr_stmt (build_chill_modify_expr (prev_ref,
431 exception_stack_decl));
432 expand_expr_stmt (build_chill_modify_expr (exception_stack_decl,
434 current_handler->handler_ref = prev_ref;
438 expand_expr_stmt (build_chill_function_call (link_handler_decl,
439 build_tree_list (NULL_TREE,
441 current_handler->handler_ref = handler_addr;
444 /* Expand: handler->__handlers = { <<array mapping names to ints } */
445 t = build1 (NOP_EXPR, build_pointer_type (handler_element_type),
446 build_chill_arrow_expr (start_handler_array (), 1));
447 expand_expr_stmt (build_chill_modify_expr (handlers_ref, t));
449 /* Emit code to unlink handler. */
450 if (inline_exception_stack_ops)
451 current_handler->unlink_cleanup
452 = build_chill_modify_expr (exception_stack_decl,
453 current_handler->handler_ref);
455 current_handler->unlink_cleanup
456 = build_chill_function_call (unlink_handler_decl,
457 build_tree_list(NULL_TREE,
458 current_handler->handler_ref));
459 cleanup_chain = tree_cons (build_int_2 (action_nesting_level, 0),
460 current_handler->unlink_cleanup,
463 /* Emit code for setjmp. */
465 current_handler->setjmp_expr =
466 build_chill_function_call (BISJ, build_tree_list (NULL_TREE, jbuf_ref));
467 expand_start_case (1, current_handler->setjmp_expr,
468 integer_type_node, "on handler");
470 chill_handle_case_label (integer_zero_node, current_handler->setjmp_expr);
473 /* Start emitting code for: <actions> ON <handlers> END.
474 Assume we've parsed <actions>, and the setup needed for it. */
479 expand_expr_stmt (current_handler->unlink_cleanup);
481 /* Emit code to jump past the handlers. */
482 current_handler->end_label = gen_label_rtx ();
483 current_handler->compiling = 1;
484 emit_jump (current_handler->end_label);
490 expand_end_case (current_handler->setjmp_expr);
492 finish_handler_array ();
494 emit_label (current_handler->end_label);
498 cleanup_chain = TREE_CHAIN (cleanup_chain);
502 chill_handle_on_labels (labels)
505 int alternative = ++current_handler->prev_on_alternative;
508 tree handler_number = build_int_2 (alternative, 0);
509 current_handler->on_alt_list =
510 tree_cons (handler_number, labels, current_handler->on_alt_list);
514 /* Find handler_number saved in pass 1. */
515 tree tmp = current_handler->on_alt_list;
516 while (TREE_INT_CST_LOW (TREE_PURPOSE (tmp)) != alternative)
517 tmp = TREE_CHAIN (tmp);
518 if (expand_exit_needed)
519 expand_exit_something (), expand_exit_needed = 0;
520 chill_handle_case_label (TREE_PURPOSE (tmp),
521 current_handler->setjmp_expr);
526 chill_start_default_handler ()
528 current_handler->else_handler = ++current_handler->prev_on_alternative;
531 chill_handle_case_default ();
536 chill_check_no_handlers ()
538 if (current_handler != NULL)
539 fatal ("internal error: on stack not empty when done");
543 initialize_exceptions ()
545 tree jmp_buf_type = build_array_type (integer_type_node,
546 build_index_type (build_int_2 (_JBLEN_2-1, 0)));
547 tree setjmp_fndecl, link_ftype;
549 = tree_cons (NULL_TREE, build_pointer_type (jmp_buf_type), void_list_node);
551 setjmp_fndecl = builtin_function ("setjmp",
552 build_function_type (integer_type_node,
555 SETJMP_LIBRARY_NAME);
556 BISJ = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (setjmp_fndecl)),
559 char_pointer_type_for_handler
560 = build_pointer_type (build_type_variant (char_type_node, 1, 0));
561 handler_element_type =
562 build_chill_struct_type (chainon
563 (build_decl (FIELD_DECL,
564 get_identifier("__exceptid"),
565 char_pointer_type_for_handler),
566 build_decl (FIELD_DECL,
567 get_identifier("__handlerno"),
568 integer_type_node)));
570 jbuf_ident = get_identifier("__jbuf");
571 prev_ident = get_identifier("__prev");
572 handlers_ident = get_identifier("__handlers");
575 build_chill_struct_type
577 (build_decl (FIELD_DECL, prev_ident, ptr_type_node),
579 (build_decl (FIELD_DECL, handlers_ident,
580 build_pointer_type (handler_element_type)),
581 build_decl (FIELD_DECL, jbuf_ident, jmp_buf_type))));
583 handler_link_pointer_type = build_pointer_type (handler_link_type);
585 if (inline_exception_stack_ops)
587 exception_stack_decl =
588 build_lang_decl (VAR_DECL,
589 get_identifier("__exceptionStack"),
590 handler_link_pointer_type);
591 TREE_STATIC (exception_stack_decl) = 1;
592 TREE_PUBLIC (exception_stack_decl) = 1;
593 DECL_EXTERNAL (exception_stack_decl) = 1;
594 push_obstacks_nochange ();
595 pushdecl(exception_stack_decl);
596 make_decl_rtl (exception_stack_decl, NULL_PTR, 1);
597 finish_decl (exception_stack_decl);
600 link_ftype = build_function_type (void_type_node,
601 tree_cons (NULL_TREE,
602 handler_link_pointer_type,
604 link_handler_decl = builtin_function ("__ch_link_handler", link_ftype,
605 NOT_BUILT_IN, NULL_PTR);
606 unlink_handler_decl = builtin_function ("__ch_unlink_handler", link_ftype,
607 NOT_BUILT_IN, NULL_PTR);
609 exceptions_initialized = 1;
612 /* Do the cleanup(s) needed for a GOTO label.
613 We only need to do the last of the cleanups. */
616 expand_goto_except_cleanup (label_level)
619 tree list = cleanup_chain;
620 tree last = NULL_TREE;
621 for ( ; list != NULL_TREE; list = TREE_CHAIN (list))
623 if (TREE_INT_CST_LOW (TREE_PURPOSE (list)) > label_level)
629 expand_expr_stmt (TREE_VALUE (last));
632 /* Returns true if there is a valid handler for EXCEPT_NAME
633 in the current static scope.
634 0 ... no handler found
635 1 ... local handler available
636 2 ... function may propagate this exception
640 is_handled (except_name)
644 struct handler_state *h = current_handler;
646 /* if we are are currently compiling this handler
647 we have to start at the next level */
648 if (h && h->compiling)
652 if (h->function != current_function_decl)
654 if (h->else_handler > 0)
656 for (t = h->on_alt_list; t != NULL_TREE; t = TREE_CHAIN (t))
658 if (value_member (except_name, TREE_VALUE (t)))
664 t = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (current_function_decl));
666 if (value_member (except_name, t))
671 /* function generates code to reraise exceptions
672 for PROC's propagating exceptions. */
675 chill_reraise_exceptions (exceptions)
680 if (exceptions == NULL_TREE)
681 return; /* just in case */
685 for (wrk = exceptions; wrk != NULL_TREE; wrk = TREE_CHAIN (wrk))
686 chill_handle_on_labels (build_tree_list (NULL_TREE, TREE_VALUE (wrk)));
691 expand_exit_needed = 0;
693 for (wrk = exceptions; wrk != NULL_TREE; wrk = TREE_CHAIN (wrk))
695 chill_handle_on_labels (TREE_VALUE (wrk));
696 /* do a CAUSE exception */
697 expand_expr_stmt (build_cause_exception (TREE_VALUE (wrk), 0));
698 expand_exit_needed = 1;