1 /* Exception Handling interface routines.
2 Copyright (C) 1996, 1997 Free Software Foundation, Inc.
3 Contributed by Mike Stump <mrs@cygnus.com>.
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, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 #if !defined(NULL_RTX) && !defined(rtx)
23 typedef struct rtx_def
*_except_rtx
;
24 #define rtx _except_rtx
27 /* The label generated by expand_builtin_eh_return. */
29 extern rtx eh_return_stub_label
;
33 /* A stack of labels. CHAIN points to the next entry in the stack. */
40 struct label_node
*chain
;
43 /* An eh_entry is used to describe one exception handling region.
45 OUTER_CONTEXT is the label used for rethrowing into the outer context.
47 EXCEPTION_HANDLER_LABEL is the label corresponding to the handler
50 LABEL_USED indicates whether a CATCH block has already used this
51 label or not. New ones are needed for additional catch blocks if
54 FALSE_LABEL is used when either setjmp/longjmp exceptions are in
55 use, or old style table exceptions. It contains the label for
56 branching to the next runtime type check as handlers are processed.
58 FINALIZATION is the tree codes for the handler, or is NULL_TREE if
59 one hasn't been generated yet, or is integer_zero_node to mark the
60 end of a group of try blocks. */
64 rtx exception_handler_label
;
70 /* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next
71 entry in the list, or is NULL if this is the last entry. */
74 struct eh_entry
*entry
;
75 struct eh_node
*chain
;
78 /* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is
79 NULL if the stack is empty. */
85 /* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the
86 end (the latest entry). HEAD and TAIL are NULL if the queue is
94 /* Start an exception handling region. All instructions emitted after
95 this point are considered to be part of the region until
96 expand_eh_region_end () is invoked. */
98 extern void expand_eh_region_start
PROTO((void));
100 /* Just like expand_eh_region_start, except if a cleanup action is
101 entered on the cleanup chain, the TREE_PURPOSE of the element put
102 on the chain is DECL. DECL should be the associated VAR_DECL, if
103 any, otherwise it should be NULL_TREE. */
105 extern void expand_eh_region_start_for_decl
PROTO((tree
));
107 /* Start an exception handling region for the given cleanup action.
108 All instructions emitted after this point are considered to be part
109 of the region until expand_eh_region_end () is invoked. CLEANUP is
110 the cleanup action to perform. The return value is true if the
111 exception region was optimized away. If that case,
112 expand_eh_region_end does not need to be called for this cleanup,
115 This routine notices one particular common case in C++ code
116 generation, and optimizes it so as to not need the exception
119 extern int expand_eh_region_start_tree
PROTO((tree
, tree
));
121 /* End an exception handling region. The information about the region
122 is found on the top of ehstack.
124 HANDLER is either the cleanup for the exception region, or if we're
125 marking the end of a try block, HANDLER is integer_zero_node.
127 HANDLER will be transformed to rtl when expand_leftover_cleanups ()
130 extern void expand_eh_region_end
PROTO((tree
));
132 /* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL
133 should be set; the other must be NULL. */
135 extern void push_label_entry
PROTO((struct label_node
**labelstack
, rtx rlabel
, tree tlabel
));
137 /* Pop the topmost entry from LABELSTACK and return its value as an
138 rtx node. If LABELSTACK is empty, return NULL. */
140 extern rtx pop_label_entry
PROTO((struct label_node
**labelstack
));
142 /* Return the topmost entry of LABELSTACK as a tree node, or return
143 NULL_TREE if LABELSTACK is empty. */
145 extern tree top_label_entry
PROTO((struct label_node
**labelstack
));
147 /* A set of insns for the catch clauses in the current function. They
148 will be emitted at the end of the current function. */
150 extern rtx catch_clauses
;
154 /* Test: is exception handling turned on? */
156 extern int doing_eh
PROTO ((int));
158 /* Toplevel initialization for EH. */
160 void set_exception_lang_code
PROTO((int));
161 void set_exception_version_code
PROTO((int));
163 /* A list of handlers asocciated with an exception region. HANDLER_LABEL
164 is the the label that control should be transfered to if the data
165 in TYPE_INFO matches an exception. a value of NULL_TREE for TYPE_INFO
166 means This is a cleanup, and must always be called. A value of
167 CATCH_ALL_TYPE works like a cleanup, but a call to the runtime matcher
168 is still performed to avoid being caught by a different language
169 exception. NEXT is a pointer to the next handler for this region.
170 NULL means there are no more. */
172 typedef struct handler_info
176 struct handler_info
*next
;
180 /* Add a new eh_entry for this function, The parameter specifies what
181 exception region number NOTE insns use to delimit this range.
182 The integer returned is uniquely identifies this exception range
183 within an internal table. */
185 int new_eh_region_entry
PROTO((int));
187 /* Add new handler information to an exception range. The first parameter
188 specifies the range number (returned from new_eh_entry()). The second
189 parameter specifies the handler. By default the handler is inserted at
190 the end of the list. A handler list may contain only ONE NULL_TREE
191 typeinfo entry. Regardless where it is positioned, a NULL_TREE entry
192 is always output as the LAST handler in the exception table for a region. */
194 void add_new_handler
PROTO((int, struct handler_info
*));
196 /* Remove a handler label. The handler label is being deleted, so all
197 regions which reference this handler should have it removed from their
198 list of possible handlers. Any region which has the final handler
199 removed can be deleted. */
201 void remove_handler
PROTO((rtx
));
203 /* Create a new handler structure initialized with the handler label and
204 typeinfo fields passed in. */
206 struct handler_info
*get_new_handler
PROTO((rtx
, void *));
208 /* Make a duplicate of an exception region by copying all the handlers
209 for an exception region. Return the new handler index. */
211 int duplicate_handlers
PROTO((int, int));
214 /* Get a pointer to the first handler in an exception region's list. */
216 struct handler_info
*get_first_handler
PROTO((int));
218 /* Find all the runtime handlers type matches currently referenced */
220 int find_all_handler_type_matches
PROTO((void ***));
222 extern void init_eh
PROTO((void));
224 /* Initialization for the per-function EH data. */
226 extern void init_eh_for_function
PROTO((void));
228 /* Generate an exception label. Use instead of gen_label_rtx */
230 extern rtx gen_exception_label
PROTO((void));
232 /* Adds an EH table entry for EH entry number N. Called from
233 final_scan_insn for NOTE_INSN_EH_REGION_BEG. */
235 extern void add_eh_table_entry
PROTO((int n
));
237 /* Start a catch clause, triggered by runtime value paramter. */
240 extern void start_catch_handler
PROTO((tree
));
243 /* End an individual catch clause. */
245 extern void end_catch_handler
PROTO((void));
247 /* Returns a non-zero value if we need to output an exception table. */
249 extern int exception_table_p
PROTO((void));
251 /* Outputs the exception table if we have one. */
253 extern void output_exception_table
PROTO((void));
255 /* Given a return address in ADDR, determine the address we should use
256 to find the corresponding EH region. */
258 extern rtx eh_outer_context
PROTO((rtx addr
));
260 /* Called at the start of a block of try statements for which there is
261 a supplied catch handler. */
263 extern void expand_start_try_stmts
PROTO((void));
265 /* Called at the start of a block of catch statements. It terminates the
266 previous set of try statements. */
268 extern void expand_start_all_catch
PROTO((void));
270 /* Called at the end of a block of catch statements. */
272 extern void expand_end_all_catch
PROTO((void));
275 /* Create a new exception region and add the handler for the region
276 onto a list. These regions will be ended (and their handlers
277 emitted) when end_protect_partials is invoked. */
279 extern void add_partial_entry
PROTO((tree handler
));
282 /* End all of the pending exception regions that have handlers added with
283 push_protect_entry (). */
285 extern void end_protect_partials
PROTO((void));
287 /* An internal throw. */
289 extern void expand_internal_throw
PROTO((void));
291 /* Called from expand_exception_blocks and expand_end_catch_block to
292 expand and pending handlers. */
294 extern void expand_leftover_cleanups
PROTO((void));
296 /* If necessary, emit insns to get EH context for the current
299 extern void emit_eh_context
PROTO((void));
301 /* Builds a list of handler labels and puts them in the global
302 variable exception_handler_labels. */
304 extern void find_exception_handler_labels
PROTO((void));
306 /* Determine if an arbitrary label is an exception label */
308 extern int is_exception_handler_label
PROTO((int));
310 /* Performs sanity checking on the check_exception_handler_labels
313 extern void check_exception_handler_labels
PROTO((void));
315 /* A stack used to keep track of the label used to resume normal program
316 flow out of the current exception handler region. */
318 extern struct label_node
*caught_return_label_stack
;
320 /* Keeps track of the label used as the context of a throw to rethrow an
321 exception to the outer exception region. */
323 extern struct label_node
*outer_context_label_stack
;
325 /* A random area used for purposes elsewhere. */
327 extern struct label_node
*false_label_stack
;
329 /* A list of labels used for exception handlers. It is created by
330 find_exception_handler_labels for the optimization passes. */
332 extern rtx exception_handler_labels
;
334 /* Performs optimizations for exception handling, such as removing
335 unnecessary exception regions. Invoked from jump_optimize (). */
337 extern void exception_optimize
PROTO((void));
339 /* Return EH context (and set it up once per fn). */
340 extern rtx get_eh_context
PROTO((void));
342 /* Get the dynamic handler chain. */
343 extern rtx get_dynamic_handler_chain
PROTO((void));
345 /* Get the dynamic cleanup chain. */
346 extern rtx get_dynamic_cleanup_chain
PROTO((void));
348 /* Throw an exception. */
350 extern void emit_throw
PROTO((void));
352 /* One to use setjmp/longjmp method of generating code. */
354 extern int exceptions_via_longjmp
;
356 /* One to enable asynchronous exception support. */
358 extern int asynchronous_exceptions
;
360 /* One to protect cleanup actions with a handler that calls
361 __terminate, zero otherwise. */
363 extern int protect_cleanup_actions_with_terminate
;
366 extern tree protect_with_terminate
PROTO((tree
));
369 extern void expand_fixup_region_start
PROTO((void));
371 extern void expand_fixup_region_end
PROTO((tree
));
374 /* Various hooks for the DWARF 2 __throw routine. */
376 void expand_builtin_unwind_init
PROTO((void));
377 rtx expand_builtin_dwarf_fp_regnum
PROTO((void));
379 rtx expand_builtin_frob_return_addr
PROTO((tree
));
380 rtx expand_builtin_extract_return_addr
PROTO((tree
));
381 rtx expand_builtin_dwarf_reg_size
PROTO((tree
, rtx
));
382 void expand_builtin_eh_return
PROTO((tree
, tree
, tree
));
384 void expand_eh_return
PROTO((void));
387 /* Checking whether 2 instructions are within the same exception region. */
389 int in_same_eh_region
PROTO((rtx
, rtx
));
390 void free_insn_eh_region
PROTO((void));
391 void init_insn_eh_region
PROTO((rtx
, int));