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. */
154 void set_exception_lang_code PROTO((short));
155 void set_exception_version_code PROTO((short));
159 /* A list of handlers asocciated with an exception region. HANDLER_LABEL
160 is the the label that control should be transfered to if the data
161 in TYPE_INFO matches an exception. a value of NULL_TREE for TYPE_INFO
162 means This is a cleanup, and must always be called. A value of
163 CATCH_ALL_TYPE works like a cleanup, but a call to the runtime matcher
164 is still performed to avoid being caught by a different language
165 exception. NEXT is a pointer to the next handler for this region.
166 NULL means there are no more. */
168 #define CATCH_ALL_TYPE (tree *) -1
170 typedef struct handler_info
174 struct handler_info *next;
178 /* Add a new eh_entry for this function, The parameter specifies what
179 exception region number NOTE insns use to delimit this range.
180 The integer returned is uniquely identifies this exception range
181 within an internal table. */
183 int new_eh_region_entry PROTO((int));
185 /* Add new handler information to an exception range. The first parameter
186 specifies the range number (returned from new_eh_entry()). The second
187 parameter specifies the handler. By default the handler is inserted at
188 the end of the list. A handler list may contain only ONE NULL_TREE
189 typeinfo entry. Regardless where it is positioned, a NULL_TREE entry
190 is always output as the LAST handler in the exception table for a region. */
192 void add_new_handler PROTO((int, struct handler_info *));
194 /* Create a new handler structure initialized with the handler label and
195 typeinfo fields passed in. */
197 struct handler_info *get_new_handler PROTO((rtx, void *));
199 /* Make a duplicate of an exception region by copying all the handlers
200 for an exception region. Return the new handler index. */
202 int duplicate_handlers PROTO((int, int));
205 /* Get a pointer to the first handler in an exception region's list. */
207 struct handler_info *get_first_handler PROTO((int));
210 extern void init_eh PROTO((void));
212 /* Initialization for the per-function EH data. */
214 extern void init_eh_for_function PROTO((void));
216 /* Generate an exception label. Use instead of gen_label_rtx */
218 extern rtx gen_exception_label PROTO((void));
220 /* Adds an EH table entry for EH entry number N. Called from
221 final_scan_insn for NOTE_INSN_EH_REGION_BEG. */
223 extern void add_eh_table_entry PROTO((int n));
225 /* Start a catch clause, triggered by runtime value paramter. */
228 extern void expand_start_catch PROTO((tree));
231 /* End a catch clause. */
233 extern void expand_end_catch PROTO((void));
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 /* If necessary, emit insns for the start of per-function unwinder for
290 the current function. */
292 extern void emit_unwinder PROTO((void));
294 /* If necessary, emit insns for the end of the per-function unwinder
295 for the current function. */
297 extern void end_eh_unwinder PROTO((void));
299 /* Builds a list of handler labels and puts them in the global
300 variable exception_handler_labels. */
302 extern void find_exception_handler_labels PROTO((void));
304 /* Determine if an arbitrary label is an exception label */
306 extern int is_exception_handler_label PROTO((int));
308 /* Performs sanity checking on the check_exception_handler_labels
311 extern void check_exception_handler_labels PROTO((void));
313 /* A stack used to keep track of the label used to resume normal program
314 flow out of the current exception handler region. */
316 extern struct label_node *caught_return_label_stack;
318 /* Keeps track of the label used as the context of a throw to rethrow an
319 exception to the outer exception region. */
321 extern struct label_node *outer_context_label_stack;
323 /* A random area used for purposes elsewhere. */
325 extern struct label_node *false_label_stack;
327 /* A list of labels used for exception handlers. It is created by
328 find_exception_handler_labels for the optimization passes. */
330 extern rtx exception_handler_labels;
332 /* Performs optimizations for exception handling, such as removing
333 unnecessary exception regions. Invoked from jump_optimize (). */
335 extern void exception_optimize PROTO((void));
337 /* Return EH context (and set it up once per fn). */
338 extern rtx get_eh_context PROTO((void));
340 /* Get the dynamic handler chain. */
341 extern rtx get_dynamic_handler_chain PROTO((void));
343 /* Get the dynamic cleanup chain. */
344 extern rtx get_dynamic_cleanup_chain PROTO((void));
346 /* Throw an exception. */
348 extern void emit_throw PROTO((void));
350 /* One to use setjmp/longjmp method of generating code. */
352 extern int exceptions_via_longjmp;
354 /* One to enable asynchronous exception support. */
356 extern int asynchronous_exceptions;
358 /* One to protect cleanup actions with a handler that calls
359 __terminate, zero otherwise. */
361 extern int protect_cleanup_actions_with_terminate;
364 extern tree protect_with_terminate PROTO((tree));
367 extern void expand_fixup_region_start PROTO((void));
369 extern void expand_fixup_region_end PROTO((tree));
372 /* Various hooks for the DWARF 2 __throw routine. */
374 void expand_builtin_unwind_init PROTO((void));
375 rtx expand_builtin_dwarf_fp_regnum PROTO((void));
376 rtx expand_builtin_eh_stub PROTO((void));
378 rtx expand_builtin_frob_return_addr PROTO((tree));
379 rtx expand_builtin_extract_return_addr PROTO((tree));
380 void expand_builtin_set_return_addr_reg PROTO((tree));
381 void expand_builtin_set_eh_regs PROTO((tree, tree));
382 rtx expand_builtin_dwarf_reg_size PROTO((tree, rtx));
386 /* Checking whether 2 instructions are within the same exception region. */
388 int in_same_eh_region PROTO((rtx, rtx));
389 void free_insn_eh_region PROTO((void));
390 void init_insn_eh_region PROTO((rtx, int));