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4956d07c MS |
1 | /* Exception Handling interface routines. |
2 | Copyright (C) 1996 Free Software Foundation, Inc. | |
3 | Contributed by Mike Stump <mrs@cygnus.com>. | |
4 | ||
5 | This file is part of GNU CC. | |
6 | ||
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) | |
10 | any later version. | |
11 | ||
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. | |
16 | ||
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. */ | |
21 | ||
22 | ||
23 | #ifndef GET_CODE | |
24 | #define rtx int * | |
25 | #endif | |
26 | ||
27 | #ifdef TREE_CODE | |
28 | ||
911fdd58 RK |
29 | /* A stack of labels. CHAIN points to the next entry in the stack. */ |
30 | ||
4956d07c MS |
31 | struct label_node { |
32 | union { | |
33 | rtx rlabel; | |
34 | tree tlabel; | |
35 | } u; | |
36 | struct label_node *chain; | |
37 | }; | |
38 | ||
911fdd58 RK |
39 | /* An eh_entry is used to describe one exception handling region. |
40 | ||
41 | START_LABEL is the label corresponding to the start of the region. | |
42 | ||
43 | END_LABEL is the label corresponding to the end of the region. | |
44 | ||
45 | EXCEPTION_HANDLER_LABEL is the label corresponding to the handler | |
46 | for this region. | |
47 | ||
48 | FINALIZATION is the tree codes for the handler, or is NULL_TREE if | |
49 | one hasn't been generated yet, or is integer_zero_node to mark the | |
50 | end of a group of try blocks. */ | |
51 | ||
4956d07c MS |
52 | struct eh_entry { |
53 | rtx start_label; | |
54 | rtx end_label; | |
55 | rtx exception_handler_label; | |
56 | ||
57 | tree finalization; | |
58 | }; | |
59 | ||
911fdd58 RK |
60 | /* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next |
61 | entry in the list, or is NULL if this is the last entry. */ | |
62 | ||
4956d07c MS |
63 | struct eh_node { |
64 | struct eh_entry *entry; | |
65 | struct eh_node *chain; | |
66 | }; | |
67 | ||
911fdd58 RK |
68 | /* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is |
69 | NULL if the stack is empty. */ | |
70 | ||
4956d07c MS |
71 | struct eh_stack { |
72 | struct eh_node *top; | |
73 | }; | |
74 | ||
911fdd58 RK |
75 | /* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the |
76 | end (the latest entry). HEAD and TAIL are NULL if the queue is | |
77 | empty. */ | |
78 | ||
4956d07c MS |
79 | struct eh_queue { |
80 | struct eh_node *head; | |
81 | struct eh_node *tail; | |
82 | }; | |
83 | ||
84 | ||
e976b8b2 MS |
85 | /* Start an exception handling region. All instructions emitted after |
86 | this point are considered to be part of the region until | |
87 | expand_eh_region_end () is invoked. */ | |
88 | ||
911fdd58 RK |
89 | extern void expand_eh_region_start PROTO((void)); |
90 | ||
4c581243 MS |
91 | /* Just like expand_eh_region_start, except if a cleanup action is |
92 | entered on the cleanup chain, the TREE_PURPOSE of the element put | |
93 | on the chain is DECL. DECL should be the associated VAR_DECL, if | |
94 | any, otherwise it should be NULL_TREE. */ | |
95 | ||
96 | extern void expand_eh_region_start_for_decl PROTO((tree)); | |
97 | ||
e976b8b2 MS |
98 | /* Start an exception handling region for the given cleanup action. |
99 | All instructions emitted after this point are considered to be part | |
100 | of the region until expand_eh_region_end () is invoked. CLEANUP is | |
101 | the cleanup action to perform. The return value is true if the | |
102 | exception region was optimized away. If that case, | |
103 | expand_eh_region_end does not need to be called for this cleanup, | |
104 | nor should it be. | |
105 | ||
106 | This routine notices one particular common case in C++ code | |
107 | generation, and optimizes it so as to not need the exception | |
108 | region. */ | |
109 | ||
4c581243 | 110 | extern int expand_eh_region_start_tree PROTO((tree, tree)); |
e976b8b2 MS |
111 | |
112 | /* End an exception handling region. The information about the region | |
113 | is found on the top of ehstack. | |
114 | ||
115 | HANDLER is either the cleanup for the exception region, or if we're | |
116 | marking the end of a try block, HANDLER is integer_zero_node. | |
117 | ||
118 | HANDLER will be transformed to rtl when expand_leftover_cleanups () | |
119 | is invoked. */ | |
120 | ||
911fdd58 RK |
121 | extern void expand_eh_region_end PROTO((tree)); |
122 | ||
123 | /* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL | |
124 | should be set; the other must be NULL. */ | |
125 | ||
4956d07c | 126 | extern void push_label_entry PROTO((struct label_node **labelstack, rtx rlabel, tree tlabel)); |
911fdd58 RK |
127 | |
128 | /* Pop the topmost entry from LABELSTACK and return its value as an | |
129 | rtx node. If LABELSTACK is empty, return NULL. */ | |
130 | ||
4956d07c | 131 | extern rtx pop_label_entry PROTO((struct label_node **labelstack)); |
911fdd58 RK |
132 | |
133 | /* Return the topmost entry of LABELSTACK as a tree node, or return | |
134 | NULL_TREE if LABELSTACK is empty. */ | |
135 | ||
4956d07c MS |
136 | extern tree top_label_entry PROTO((struct label_node **labelstack)); |
137 | ||
911fdd58 RK |
138 | /* A set of insns for the catch clauses in the current function. They |
139 | will be emitted at the end of the current function. */ | |
140 | ||
4956d07c | 141 | extern rtx catch_clauses; |
4956d07c MS |
142 | |
143 | #endif | |
144 | ||
145 | struct function; | |
146 | ||
911fdd58 RK |
147 | /* Toplevel initialization for EH. */ |
148 | ||
4956d07c | 149 | extern void init_eh PROTO((void)); |
911fdd58 RK |
150 | |
151 | /* Initialization for the per-function EH data. */ | |
152 | ||
4956d07c | 153 | extern void init_eh_for_function PROTO((void)); |
911fdd58 RK |
154 | |
155 | /* Saves the current per-function EH data into P. */ | |
156 | ||
4956d07c | 157 | extern void save_eh_status PROTO((struct function *p)); |
911fdd58 RK |
158 | |
159 | /* Restores the per-function EH data from P. */ | |
160 | ||
4956d07c | 161 | extern void restore_eh_status PROTO((struct function *p)); |
911fdd58 RK |
162 | |
163 | /* Adds an EH table entry for EH entry number N. Called from | |
164 | final_scan_insn for NOTE_INSN_EH_REGION_BEG. */ | |
165 | ||
166 | extern void add_eh_table_entry PROTO((int n)); | |
167 | ||
168 | /* Returns a non-zero value if we need to output an exception table. */ | |
169 | ||
4956d07c | 170 | extern int exception_table_p PROTO((void)); |
911fdd58 RK |
171 | |
172 | /* Outputs the exception table if we have one. */ | |
173 | ||
4956d07c | 174 | extern void output_exception_table PROTO((void)); |
911fdd58 RK |
175 | |
176 | /* Given a return address in ADDR, determine the address we should use | |
177 | to find the corresponding EH region. */ | |
178 | ||
179 | extern rtx eh_outer_context PROTO((rtx addr)); | |
180 | ||
181 | /* Called at the start of a block of try statements for which there is | |
182 | a supplied catch handler. */ | |
183 | ||
184 | extern void expand_start_try_stmts PROTO((void)); | |
185 | ||
186 | /* Called at the start of a block of catch statements. It terminates the | |
187 | previous set of try statements. */ | |
188 | ||
189 | extern void expand_start_all_catch PROTO((void)); | |
190 | ||
191 | /* Called at the end of a block of catch statements. */ | |
192 | ||
193 | extern void expand_end_all_catch PROTO((void)); | |
194 | ||
195 | #ifdef TREE_CODE | |
196 | /* Create a new exception region and add the handler for the region | |
197 | onto a list. These regions will be ended (and their handlers | |
198 | emitted) when end_protect_partials is invoked. */ | |
199 | ||
200 | extern void add_partial_entry PROTO((tree handler)); | |
201 | #endif | |
202 | ||
203 | /* End all of the pending exception regions that have handlers added with | |
204 | push_protect_entry (). */ | |
205 | ||
206 | extern void end_protect_partials PROTO((void)); | |
207 | ||
208 | /* An internal throw with a direct CONTEXT we want to throw | |
209 | from. CONTEXT must be a label. */ | |
210 | ||
211 | extern void expand_internal_throw PROTO((rtx context)); | |
212 | ||
213 | /* Called from expand_exception_blocks and expand_end_catch_block to | |
214 | expand and pending handlers. */ | |
215 | ||
216 | extern void expand_leftover_cleanups PROTO((void)); | |
217 | ||
218 | /* If necessary, emit insns for the start of per-function unwinder for | |
219 | the current function. */ | |
220 | ||
4956d07c | 221 | extern void emit_unwinder PROTO((void)); |
911fdd58 RK |
222 | |
223 | /* If necessary, emit insns for the end of the per-function unwinder | |
224 | for the current function. */ | |
225 | ||
4956d07c | 226 | extern void end_eh_unwinder PROTO((void)); |
4956d07c | 227 | |
911fdd58 RK |
228 | /* Builds a list of handler labels and puts them in the global |
229 | variable exception_handler_labels. */ | |
230 | ||
231 | extern void find_exception_handler_labels PROTO((void)); | |
232 | ||
233 | /* Performs sanity checking on the check_exception_handler_labels | |
234 | list. */ | |
235 | ||
236 | extern void check_exception_handler_labels PROTO((void)); | |
237 | ||
238 | /* A stack used to keep track of the label used to resume normal program | |
239 | flow out of the current exception handler region. */ | |
4956d07c MS |
240 | |
241 | extern struct label_node *caught_return_label_stack; | |
911fdd58 RK |
242 | |
243 | /* A random area used for purposes elsewhere. */ | |
244 | ||
4956d07c MS |
245 | extern struct label_node *false_label_stack; |
246 | ||
911fdd58 RK |
247 | /* A list of labels used for exception handlers. It is created by |
248 | find_exception_handler_labels for the optimization passes. */ | |
249 | ||
4956d07c MS |
250 | extern rtx exception_handler_labels; |
251 | ||
252 | /* The rtx for the saved PC value. */ | |
253 | ||
254 | extern rtx eh_saved_pc_rtx; | |
255 | ||
911fdd58 RK |
256 | /* Performs optimizations for exception handling, such as removing |
257 | unnecessary exception regions. Invoked from jump_optimize (). */ | |
258 | ||
4956d07c | 259 | extern void exception_optimize PROTO((void)); |
e976b8b2 MS |
260 | |
261 | /* Get the dynamic handler chain. */ | |
262 | extern rtx get_dynamic_handler_chain PROTO((void)); | |
263 | ||
264 | /* Get the dynamic cleanup chain. */ | |
265 | extern rtx get_dynamic_cleanup_chain PROTO((void)); | |
266 | ||
267 | /* Throw an exception. */ | |
268 | ||
269 | extern void emit_throw PROTO((void)); | |
270 | ||
271 | /* One to use setjmp/longjmp method of generating code. */ | |
272 | ||
273 | extern int exceptions_via_longjmp; | |
274 | ||
275 | /* One to enable asynchronous exception support. */ | |
276 | ||
277 | extern int asynchronous_exceptions; | |
278 | ||
279 | /* One to protect cleanup actions with a handler that calls | |
280 | __terminate, zero otherwise. */ | |
281 | ||
282 | extern int protect_cleanup_actions_with_terminate; | |
283 | ||
284 | #ifdef TREE_CODE | |
285 | extern tree protect_with_terminate PROTO((tree)); | |
286 | #endif |