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
29 /* A stack of labels. CHAIN points to the next entry in the stack. */
36 struct label_node
*chain
;
39 /* An eh_entry is used to describe one exception handling region.
41 OUTER_CONTEXT is the label used for rethrowing into the outer context.
43 EXCEPTION_HANDLER_LABEL is the label corresponding to the handler
46 LABEL_USED indicates whether a CATCH block has already used this
47 label or not. New ones are needed for additional catch blocks if
50 FINALIZATION is the tree codes for the handler, or is NULL_TREE if
51 one hasn't been generated yet, or is integer_zero_node to mark the
52 end of a group of try blocks. */
56 rtx exception_handler_label
;
61 /* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next
62 entry in the list, or is NULL if this is the last entry. */
65 struct eh_entry
*entry
;
66 struct eh_node
*chain
;
69 /* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is
70 NULL if the stack is empty. */
76 /* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the
77 end (the latest entry). HEAD and TAIL are NULL if the queue is
86 /* Start an exception handling region. All instructions emitted after
87 this point are considered to be part of the region until
88 expand_eh_region_end () is invoked. */
90 extern void expand_eh_region_start
PROTO((void));
92 /* Just like expand_eh_region_start, except if a cleanup action is
93 entered on the cleanup chain, the TREE_PURPOSE of the element put
94 on the chain is DECL. DECL should be the associated VAR_DECL, if
95 any, otherwise it should be NULL_TREE. */
97 extern void expand_eh_region_start_for_decl
PROTO((tree
));
99 /* Start an exception handling region for the given cleanup action.
100 All instructions emitted after this point are considered to be part
101 of the region until expand_eh_region_end () is invoked. CLEANUP is
102 the cleanup action to perform. The return value is true if the
103 exception region was optimized away. If that case,
104 expand_eh_region_end does not need to be called for this cleanup,
107 This routine notices one particular common case in C++ code
108 generation, and optimizes it so as to not need the exception
111 extern int expand_eh_region_start_tree
PROTO((tree
, tree
));
113 /* End an exception handling region. The information about the region
114 is found on the top of ehstack.
116 HANDLER is either the cleanup for the exception region, or if we're
117 marking the end of a try block, HANDLER is integer_zero_node.
119 HANDLER will be transformed to rtl when expand_leftover_cleanups ()
122 extern void expand_eh_region_end
PROTO((tree
));
124 /* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL
125 should be set; the other must be NULL. */
127 extern void push_label_entry
PROTO((struct label_node
**labelstack
, rtx rlabel
, tree tlabel
));
129 /* Pop the topmost entry from LABELSTACK and return its value as an
130 rtx node. If LABELSTACK is empty, return NULL. */
132 extern rtx pop_label_entry
PROTO((struct label_node
**labelstack
));
134 /* Return the topmost entry of LABELSTACK as a tree node, or return
135 NULL_TREE if LABELSTACK is empty. */
137 extern tree top_label_entry
PROTO((struct label_node
**labelstack
));
139 /* A set of insns for the catch clauses in the current function. They
140 will be emitted at the end of the current function. */
142 extern rtx catch_clauses
;
146 /* Test: is exception handling turned on? */
148 extern int doing_eh
PROTO ((int));
150 /* Toplevel initialization for EH. */
152 void set_exception_lang_code
PROTO((short));
153 void set_exception_version_code
PROTO((short));
155 /* A list of handlers asocciated with an exception region. HANDLER_LABEL
156 is the the label that control should be transfered to if the data
157 in TYPE_INFO matches an exception. a value of NULL_TREE for TYPE_INFO
158 means This is a cleanup, and must always be called. A value of
159 CATCH_ALL_TYPE works like a cleanup, but a call to the runtime matcher
160 is still performed to avoid being caught by a different language
161 exception. NEXT is a pointer to the next handler for this region.
162 NULL means there are no more. */
164 typedef struct handler_info
168 struct handler_info
*next
;
172 /* Add a new eh_entry for this function, The parameter specifies what
173 exception region number NOTE insns use to delimit this range.
174 The integer returned is uniquely identifies this exception range
175 within an internal table. */
177 int new_eh_region_entry
PROTO((int));
179 /* Add new handler information to an exception range. The first parameter
180 specifies the range number (returned from new_eh_entry()). The second
181 parameter specifies the handler. By default the handler is inserted at
182 the end of the list. A handler list may contain only ONE NULL_TREE
183 typeinfo entry. Regardless where it is positioned, a NULL_TREE entry
184 is always output as the LAST handler in the exception table for a region. */
186 void add_new_handler
PROTO((int, struct handler_info
*));
188 /* Remove a handler label. The handler label is being deleted, so all
189 regions which reference this handler should have it removed from their
190 list of possible handlers. Any region which has the final handler
191 removed can be deleted. */
193 void remove_handler
PROTO((rtx
));
195 /* Create a new handler structure initialized with the handler label and
196 typeinfo fields passed in. */
198 struct handler_info
*get_new_handler
PROTO((rtx
, void *));
200 /* Make a duplicate of an exception region by copying all the handlers
201 for an exception region. Return the new handler index. */
203 int duplicate_handlers
PROTO((int, int));
206 /* Get a pointer to the first handler in an exception region's list. */
208 struct handler_info
*get_first_handler
PROTO((int));
210 /* Find all the runtime handlers type matches currently referenced */
212 int find_all_handler_type_matches
PROTO((void ***));
214 extern void init_eh
PROTO((void));
216 /* Initialization for the per-function EH data. */
218 extern void init_eh_for_function
PROTO((void));
220 /* Generate an exception label. Use instead of gen_label_rtx */
222 extern rtx gen_exception_label
PROTO((void));
224 /* Adds an EH table entry for EH entry number N. Called from
225 final_scan_insn for NOTE_INSN_EH_REGION_BEG. */
227 extern void add_eh_table_entry
PROTO((int n
));
229 /* Start a catch clause, triggered by runtime value paramter. */
232 extern void start_catch_handler
PROTO((tree
));
235 /* Returns a non-zero value if we need to output an exception table. */
237 extern int exception_table_p
PROTO((void));
239 /* Outputs the exception table if we have one. */
241 extern void output_exception_table
PROTO((void));
243 /* Given a return address in ADDR, determine the address we should use
244 to find the corresponding EH region. */
246 extern rtx eh_outer_context
PROTO((rtx addr
));
248 /* Called at the start of a block of try statements for which there is
249 a supplied catch handler. */
251 extern void expand_start_try_stmts
PROTO((void));
253 /* Called at the start of a block of catch statements. It terminates the
254 previous set of try statements. */
256 extern void expand_start_all_catch
PROTO((void));
258 /* Called at the end of a block of catch statements. */
260 extern void expand_end_all_catch
PROTO((void));
263 /* Create a new exception region and add the handler for the region
264 onto a list. These regions will be ended (and their handlers
265 emitted) when end_protect_partials is invoked. */
267 extern void add_partial_entry
PROTO((tree handler
));
270 /* End all of the pending exception regions that have handlers added with
271 push_protect_entry (). */
273 extern void end_protect_partials
PROTO((void));
275 /* An internal throw. */
277 extern void expand_internal_throw
PROTO((void));
279 /* Called from expand_exception_blocks and expand_end_catch_block to
280 expand and pending handlers. */
282 extern void expand_leftover_cleanups
PROTO((void));
284 /* If necessary, emit insns to get EH context for the current
287 extern void emit_eh_context
PROTO((void));
289 /* Builds a list of handler labels and puts them in the global
290 variable exception_handler_labels. */
292 extern void find_exception_handler_labels
PROTO((void));
294 /* Determine if an arbitrary label is an exception label */
296 extern int is_exception_handler_label
PROTO((int));
298 /* Performs sanity checking on the check_exception_handler_labels
301 extern void check_exception_handler_labels
PROTO((void));
303 /* A stack used to keep track of the label used to resume normal program
304 flow out of the current exception handler region. */
306 extern struct label_node
*caught_return_label_stack
;
308 /* Keeps track of the label used as the context of a throw to rethrow an
309 exception to the outer exception region. */
311 extern struct label_node
*outer_context_label_stack
;
313 /* A random area used for purposes elsewhere. */
315 extern struct label_node
*false_label_stack
;
317 /* A list of labels used for exception handlers. It is created by
318 find_exception_handler_labels for the optimization passes. */
320 extern rtx exception_handler_labels
;
322 /* Performs optimizations for exception handling, such as removing
323 unnecessary exception regions. Invoked from jump_optimize (). */
325 extern void exception_optimize
PROTO((void));
327 /* Return EH context (and set it up once per fn). */
328 extern rtx get_eh_context
PROTO((void));
330 /* Get the dynamic handler chain. */
331 extern rtx get_dynamic_handler_chain
PROTO((void));
333 /* Get the dynamic cleanup chain. */
334 extern rtx get_dynamic_cleanup_chain
PROTO((void));
336 /* Throw an exception. */
338 extern void emit_throw
PROTO((void));
340 /* One to use setjmp/longjmp method of generating code. */
342 extern int exceptions_via_longjmp
;
344 /* One to enable asynchronous exception support. */
346 extern int asynchronous_exceptions
;
348 /* One to protect cleanup actions with a handler that calls
349 __terminate, zero otherwise. */
351 extern int protect_cleanup_actions_with_terminate
;
354 extern tree protect_with_terminate
PROTO((tree
));
357 extern void expand_fixup_region_start
PROTO((void));
359 extern void expand_fixup_region_end
PROTO((tree
));
362 /* Various hooks for the DWARF 2 __throw routine. */
364 void expand_builtin_unwind_init
PROTO((void));
365 rtx expand_builtin_dwarf_fp_regnum
PROTO((void));
366 rtx expand_builtin_eh_stub
PROTO((void));
367 rtx expand_builtin_eh_stub_old
PROTO((void));
369 rtx expand_builtin_frob_return_addr
PROTO((tree
));
370 rtx expand_builtin_extract_return_addr
PROTO((tree
));
371 void expand_builtin_set_return_addr_reg
PROTO((tree
));
372 void expand_builtin_set_eh_regs
PROTO((tree
, tree
));
373 rtx expand_builtin_dwarf_reg_size
PROTO((tree
, rtx
));
377 /* Checking whether 2 instructions are within the same exception region. */
379 int in_same_eh_region
PROTO((rtx
, rtx
));
380 void free_insn_eh_region
PROTO((void));
381 void init_insn_eh_region
PROTO((rtx
, int));