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8d08fdba | 1 | /* Handle exceptional things in C++. |
c913b6f1 KG |
2 | Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, |
3 | 2000, 2001 Free Software Foundation, Inc. | |
8d2733ca MS |
4 | Contributed by Michael Tiemann <tiemann@cygnus.com> |
5 | Rewritten by Mike Stump <mrs@cygnus.com>, based upon an | |
6 | initial re-implementation courtesy Tad Hunt. | |
8d08fdba MS |
7 | |
8 | This file is part of GNU CC. | |
9 | ||
10 | GNU CC is free software; you can redistribute it and/or modify | |
11 | it under the terms of the GNU General Public License as published by | |
12 | the Free Software Foundation; either version 2, or (at your option) | |
13 | any later version. | |
14 | ||
15 | GNU CC is distributed in the hope that it will be useful, | |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU General Public License | |
21 | along with GNU CC; see the file COPYING. If not, write to | |
e9fa0c7c RK |
22 | the Free Software Foundation, 59 Temple Place - Suite 330, |
23 | Boston, MA 02111-1307, USA. */ | |
8d08fdba MS |
24 | |
25 | ||
8d08fdba | 26 | #include "config.h" |
8d052bc7 | 27 | #include "system.h" |
8d08fdba MS |
28 | #include "tree.h" |
29 | #include "rtl.h" | |
8f17b5c5 | 30 | #include "expr.h" |
8d08fdba MS |
31 | #include "cp-tree.h" |
32 | #include "flags.h" | |
8d2733ca | 33 | #include "obstack.h" |
21451173 | 34 | #include "output.h" |
6467930b | 35 | #include "except.h" |
54f92bfb | 36 | #include "toplev.h" |
8d08fdba | 37 | |
93ca4ba7 | 38 | static void push_eh_cleanup PARAMS ((tree)); |
52a11cbf | 39 | static tree prepare_eh_type PARAMS ((tree)); |
158991b7 | 40 | static tree build_eh_type_type PARAMS ((tree)); |
52a11cbf | 41 | static tree do_begin_catch PARAMS ((void)); |
93ca4ba7 | 42 | static int dtor_nothrow PARAMS ((tree)); |
52a11cbf RH |
43 | static tree do_end_catch PARAMS ((tree)); |
44 | static void push_eh_cleanup PARAMS ((tree)); | |
45 | static bool decl_is_java_type PARAMS ((tree decl, int err)); | |
52a11cbf RH |
46 | static void initialize_handler_parm PARAMS ((tree, tree)); |
47 | static tree do_allocate_exception PARAMS ((tree)); | |
158991b7 | 48 | static int complete_ptr_ref_or_void_ptr_p PARAMS ((tree, tree)); |
d064d75a | 49 | static bool is_admissible_throw_operand PARAMS ((tree)); |
fbd40359 ZW |
50 | static int can_convert_eh PARAMS ((tree, tree)); |
51 | static void check_handlers_1 PARAMS ((tree, tree)); | |
e6855a2d | 52 | static tree cp_protect_cleanup_actions PARAMS ((void)); |
8d2733ca | 53 | |
8d2733ca | 54 | #include "decl.h" |
8d2733ca | 55 | #include "obstack.h" |
8d2733ca | 56 | |
52a11cbf | 57 | /* Sets up all the global eh stuff that needs to be initialized at the |
bbd0d54a | 58 | start of compilation. */ |
8d08fdba | 59 | |
8d08fdba | 60 | void |
8d2733ca | 61 | init_exception_processing () |
8d08fdba | 62 | { |
52a11cbf RH |
63 | tree tmp; |
64 | ||
52a11cbf | 65 | /* void std::terminate (); */ |
1dbb6023 | 66 | push_namespace (std_identifier); |
52a11cbf RH |
67 | tmp = build_function_type (void_type_node, void_list_node); |
68 | terminate_node = build_cp_library_fn_ptr ("terminate", tmp); | |
9cd64686 | 69 | TREE_THIS_VOLATILE (terminate_node) = 1; |
0c11ada6 | 70 | TREE_NOTHROW (terminate_node) = 1; |
1dbb6023 | 71 | pop_namespace (); |
8ccc31eb | 72 | |
52a11cbf RH |
73 | /* void __cxa_call_unexpected(void *); */ |
74 | tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node); | |
75 | tmp = build_function_type (void_type_node, tmp); | |
76 | call_unexpected_node | |
77 | = push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp); | |
6874c264 | 78 | |
52a11cbf RH |
79 | eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS |
80 | ? "__gxx_personality_sj0" | |
81 | : "__gxx_personality_v0"); | |
6874c264 | 82 | |
52a11cbf | 83 | lang_eh_runtime_type = build_eh_type_type; |
e6855a2d | 84 | lang_protect_cleanup_actions = &cp_protect_cleanup_actions; |
6874c264 JM |
85 | } |
86 | ||
e6855a2d MM |
87 | /* Returns an expression to be executed if an unhandled exception is |
88 | propogated out of a cleanup region. */ | |
89 | ||
90 | static tree | |
91 | cp_protect_cleanup_actions () | |
92 | { | |
93 | /* [except.terminate] | |
94 | ||
95 | When the destruction of an object during stack unwinding exits | |
96 | using an exception ... void terminate(); is called. */ | |
97 | return build_call (terminate_node, NULL_TREE); | |
98 | } | |
99 | ||
6874c264 | 100 | static tree |
52a11cbf | 101 | prepare_eh_type (type) |
f30432d7 | 102 | tree type; |
8d08fdba | 103 | { |
52a11cbf RH |
104 | if (type == NULL_TREE) |
105 | return type; | |
f30432d7 MS |
106 | if (type == error_mark_node) |
107 | return error_mark_node; | |
8d2733ca | 108 | |
e92cc029 | 109 | /* peel back references, so they match. */ |
f30432d7 MS |
110 | if (TREE_CODE (type) == REFERENCE_TYPE) |
111 | type = TREE_TYPE (type); | |
8d08fdba | 112 | |
e92cc029 | 113 | /* Peel off cv qualifiers. */ |
f30432d7 | 114 | type = TYPE_MAIN_VARIANT (type); |
8d2733ca | 115 | |
52a11cbf | 116 | return type; |
8d08fdba | 117 | } |
8d08fdba | 118 | |
e5f614d7 | 119 | /* Build the address of a typeinfo decl for use in the runtime |
52a11cbf | 120 | matching field of the exception model. */ |
5816cb14 AM |
121 | |
122 | static tree | |
52a11cbf | 123 | build_eh_type_type (type) |
5816cb14 AM |
124 | tree type; |
125 | { | |
5816cb14 | 126 | tree exp; |
5816cb14 | 127 | |
93ca4ba7 JM |
128 | if (type == NULL_TREE || type == error_mark_node) |
129 | return type; | |
5816cb14 | 130 | |
52a11cbf RH |
131 | if (decl_is_java_type (type, 0)) |
132 | exp = build_java_class_ref (TREE_TYPE (type)); | |
133 | else | |
134 | exp = get_tinfo_decl (type); | |
5816cb14 | 135 | |
e5f614d7 | 136 | mark_used (exp); |
db48b831 | 137 | exp = build1 (ADDR_EXPR, ptr_type_node, exp); |
5816cb14 | 138 | |
52a11cbf | 139 | return exp; |
5816cb14 AM |
140 | } |
141 | ||
52a11cbf RH |
142 | tree |
143 | build_exc_ptr () | |
144 | { | |
145 | return build (EXC_PTR_EXPR, ptr_type_node); | |
146 | } | |
147 | ||
148 | /* Build up a call to __cxa_begin_catch, to tell the runtime that the | |
149 | exception has been handled. */ | |
93ca4ba7 | 150 | |
52a11cbf RH |
151 | static tree |
152 | do_begin_catch () | |
9c606f69 | 153 | { |
52a11cbf RH |
154 | tree fn; |
155 | ||
156 | fn = get_identifier ("__cxa_begin_catch"); | |
157 | if (IDENTIFIER_GLOBAL_VALUE (fn)) | |
158 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
159 | else | |
9c606f69 | 160 | { |
52a11cbf RH |
161 | /* Declare void* __cxa_begin_catch (void *). */ |
162 | tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node); | |
163 | fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp)); | |
9c606f69 | 164 | } |
52a11cbf RH |
165 | |
166 | return build_function_call (fn, tree_cons (NULL_TREE, build_exc_ptr (), | |
167 | NULL_TREE)); | |
9c606f69 AM |
168 | } |
169 | ||
93ca4ba7 JM |
170 | /* Returns nonzero if cleaning up an exception of type TYPE (which can be |
171 | NULL_TREE for a ... handler) will not throw an exception. */ | |
172 | ||
173 | static int | |
174 | dtor_nothrow (type) | |
175 | tree type; | |
176 | { | |
177 | tree fn; | |
178 | ||
179 | if (type == NULL_TREE) | |
180 | return 0; | |
181 | ||
182 | if (! TYPE_HAS_DESTRUCTOR (type)) | |
183 | return 1; | |
184 | ||
185 | fn = lookup_member (type, dtor_identifier, 0, 0); | |
186 | fn = TREE_VALUE (fn); | |
187 | return TREE_NOTHROW (fn); | |
188 | } | |
189 | ||
52a11cbf | 190 | /* Build up a call to __cxa_end_catch, to destroy the exception object |
93ca4ba7 | 191 | for the current catch block if no others are currently using it. */ |
6467930b | 192 | |
c7ae64f2 | 193 | static tree |
52a11cbf | 194 | do_end_catch (type) |
93ca4ba7 | 195 | tree type; |
72b7eeff | 196 | { |
6874c264 | 197 | tree fn, cleanup; |
52a11cbf RH |
198 | |
199 | fn = get_identifier ("__cxa_end_catch"); | |
6874c264 JM |
200 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
201 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
202 | else | |
203 | { | |
52a11cbf RH |
204 | /* Declare void __cxa_end_catch (). */ |
205 | fn = push_void_library_fn (fn, void_list_node); | |
0c11ada6 JM |
206 | /* This can throw if the destructor for the exception throws. */ |
207 | TREE_NOTHROW (fn) = 0; | |
6874c264 | 208 | } |
72b7eeff | 209 | |
52a11cbf | 210 | cleanup = build_function_call (fn, NULL_TREE); |
93ca4ba7 | 211 | TREE_NOTHROW (cleanup) = dtor_nothrow (type); |
52a11cbf | 212 | |
c0700ea5 | 213 | return cleanup; |
c7ae64f2 JM |
214 | } |
215 | ||
216 | /* This routine creates the cleanup for the current exception. */ | |
72b7eeff | 217 | |
c7ae64f2 | 218 | static void |
93ca4ba7 JM |
219 | push_eh_cleanup (type) |
220 | tree type; | |
c7ae64f2 | 221 | { |
52a11cbf | 222 | finish_decl_cleanup (NULL_TREE, do_end_catch (type)); |
f4a23343 JM |
223 | } |
224 | ||
e97f22c9 TT |
225 | /* Return nonzero value if DECL is a Java type suitable for catch or |
226 | throw. */ | |
227 | ||
52a11cbf | 228 | static bool |
e97f22c9 TT |
229 | decl_is_java_type (decl, err) |
230 | tree decl; | |
231 | int err; | |
232 | { | |
52a11cbf RH |
233 | bool r = (TREE_CODE (decl) == POINTER_TYPE |
234 | && TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE | |
235 | && TYPE_FOR_JAVA (TREE_TYPE (decl))); | |
e97f22c9 TT |
236 | |
237 | if (err) | |
238 | { | |
239 | if (TREE_CODE (decl) == REFERENCE_TYPE | |
240 | && TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE | |
241 | && TYPE_FOR_JAVA (TREE_TYPE (decl))) | |
242 | { | |
243 | /* Can't throw a reference. */ | |
244 | cp_error ("type `%T' is disallowed in Java `throw' or `catch'", | |
245 | decl); | |
246 | } | |
247 | ||
248 | if (r) | |
249 | { | |
250 | tree jthrow_node | |
251 | = IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable")); | |
400500c4 | 252 | |
e97f22c9 | 253 | if (jthrow_node == NULL_TREE) |
400500c4 RK |
254 | fatal_error |
255 | ("call to Java `catch' or `throw' with `jthrowable' undefined"); | |
256 | ||
e97f22c9 TT |
257 | jthrow_node = TREE_TYPE (TREE_TYPE (jthrow_node)); |
258 | ||
259 | if (! DERIVED_FROM_P (jthrow_node, TREE_TYPE (decl))) | |
260 | { | |
261 | /* Thrown object must be a Throwable. */ | |
262 | cp_error ("type `%T' is not derived from `java::lang::Throwable'", | |
263 | TREE_TYPE (decl)); | |
264 | } | |
265 | } | |
266 | } | |
267 | ||
268 | return r; | |
269 | } | |
270 | ||
1f730ff7 ZW |
271 | /* Select the personality routine to be used for exception handling, |
272 | or issue an error if we need two different ones in the same | |
273 | translation unit. | |
274 | ??? At present eh_personality_libfunc is set to | |
275 | __gxx_personality_(sj|v)0 in init_exception_processing - should it | |
276 | be done here instead? */ | |
277 | void | |
278 | choose_personality_routine (lang) | |
279 | enum languages lang; | |
52a11cbf RH |
280 | { |
281 | static enum { | |
282 | chose_none, | |
283 | chose_cpp, | |
284 | chose_java, | |
285 | gave_error | |
286 | } state; | |
287 | ||
288 | switch (state) | |
289 | { | |
1f730ff7 ZW |
290 | case gave_error: |
291 | return; | |
52a11cbf RH |
292 | |
293 | case chose_cpp: | |
1f730ff7 ZW |
294 | if (lang != lang_cplusplus) |
295 | goto give_error; | |
296 | return; | |
297 | ||
52a11cbf | 298 | case chose_java: |
1f730ff7 ZW |
299 | if (lang != lang_java) |
300 | goto give_error; | |
301 | return; | |
302 | ||
303 | case chose_none: | |
304 | ; /* proceed to language selection */ | |
305 | } | |
306 | ||
307 | switch (lang) | |
308 | { | |
309 | case lang_cplusplus: | |
310 | state = chose_cpp; | |
52a11cbf RH |
311 | break; |
312 | ||
1f730ff7 ZW |
313 | case lang_java: |
314 | state = chose_java; | |
315 | eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS | |
316 | ? "__gcj_personality_sj0" | |
317 | : "__gcj_personality_v0"); | |
52a11cbf | 318 | break; |
1f730ff7 ZW |
319 | |
320 | default: | |
321 | abort (); | |
52a11cbf | 322 | } |
1f730ff7 ZW |
323 | return; |
324 | ||
325 | give_error: | |
326 | error ("mixing C++ and Java catches in a single translation unit"); | |
327 | state = gave_error; | |
52a11cbf RH |
328 | } |
329 | ||
b35d4555 | 330 | /* Initialize the catch parameter DECL. */ |
6467930b | 331 | |
b35d4555 | 332 | static void |
52a11cbf | 333 | initialize_handler_parm (decl, exp) |
3c5c0849 | 334 | tree decl; |
52a11cbf | 335 | tree exp; |
8d08fdba | 336 | { |
b35d4555 MM |
337 | tree init; |
338 | tree init_type; | |
339 | ||
340 | /* Make sure we mark the catch param as used, otherwise we'll get a | |
341 | warning about an unused ((anonymous)). */ | |
342 | TREE_USED (decl) = 1; | |
343 | ||
52a11cbf RH |
344 | /* Figure out the type that the initializer is. Pointers are returned |
345 | adjusted by value from __cxa_begin_catch. Others are returned by | |
346 | reference. */ | |
b35d4555 | 347 | init_type = TREE_TYPE (decl); |
c93586fa | 348 | if (! TYPE_PTR_P (init_type) |
52a11cbf | 349 | && TREE_CODE (init_type) != REFERENCE_TYPE) |
b35d4555 MM |
350 | init_type = build_reference_type (init_type); |
351 | ||
1f730ff7 ZW |
352 | choose_personality_routine (decl_is_java_type (init_type, 0) |
353 | ? lang_java : lang_cplusplus); | |
b35d4555 MM |
354 | |
355 | /* Since pointers are passed by value, initialize a reference to | |
52a11cbf | 356 | pointer catch parm with the address of the temporary. */ |
c93586fa RS |
357 | if (TREE_CODE (init_type) == REFERENCE_TYPE |
358 | && TYPE_PTR_P (TREE_TYPE (init_type))) | |
b35d4555 MM |
359 | exp = build_unary_op (ADDR_EXPR, exp, 1); |
360 | ||
52a11cbf | 361 | exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0); |
b35d4555 MM |
362 | |
363 | init = convert_from_reference (exp); | |
364 | ||
365 | /* If the constructor for the catch parm exits via an exception, we | |
366 | must call terminate. See eh23.C. */ | |
367 | if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl))) | |
faf5394a | 368 | { |
b35d4555 MM |
369 | /* Generate the copy constructor call directly so we can wrap it. |
370 | See also expand_default_init. */ | |
371 | init = ocp_convert (TREE_TYPE (decl), init, | |
372 | CONV_IMPLICIT|CONV_FORCE_TEMP, 0); | |
52a11cbf | 373 | init = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (init), init); |
faf5394a MS |
374 | } |
375 | ||
b35d4555 MM |
376 | /* Let `cp_finish_decl' know that this initializer is ok. */ |
377 | DECL_INITIAL (decl) = error_mark_node; | |
378 | decl = pushdecl (decl); | |
8d2733ca | 379 | |
b35d4555 | 380 | start_decl_1 (decl); |
cd9f6678 | 381 | cp_finish_decl (decl, init, NULL_TREE, |
b35d4555 | 382 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
5816cb14 AM |
383 | } |
384 | ||
b35d4555 | 385 | /* Call this to start a catch block. DECL is the catch parameter. */ |
5816cb14 | 386 | |
b35d4555 MM |
387 | tree |
388 | expand_start_catch_block (decl) | |
3c5c0849 | 389 | tree decl; |
5816cb14 | 390 | { |
52a11cbf RH |
391 | tree exp = NULL_TREE; |
392 | tree type; | |
393 | bool is_java; | |
5816cb14 | 394 | |
b35d4555 MM |
395 | if (! doing_eh (1)) |
396 | return NULL_TREE; | |
5816cb14 | 397 | |
b35d4555 | 398 | /* Make sure this declaration is reasonable. */ |
3c5c0849 MM |
399 | if (decl && !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl), NULL_TREE)) |
400 | decl = NULL_TREE; | |
5816cb14 | 401 | |
52a11cbf RH |
402 | if (decl) |
403 | type = prepare_eh_type (TREE_TYPE (decl)); | |
404 | else | |
405 | type = NULL_TREE; | |
52a11cbf RH |
406 | |
407 | is_java = false; | |
408 | if (decl) | |
e97f22c9 | 409 | { |
52a11cbf | 410 | tree init; |
5816cb14 | 411 | |
52a11cbf RH |
412 | if (decl_is_java_type (type, 1)) |
413 | { | |
414 | /* Java only passes object via pointer and doesn't require | |
415 | adjusting. The java object is immediately before the | |
416 | generic exception header. */ | |
417 | init = build_exc_ptr (); | |
418 | init = build1 (NOP_EXPR, build_pointer_type (type), init); | |
419 | init = build (MINUS_EXPR, TREE_TYPE (init), init, | |
420 | TYPE_SIZE_UNIT (TREE_TYPE (init))); | |
3e411c3f | 421 | init = build_indirect_ref (init, NULL); |
52a11cbf RH |
422 | is_java = true; |
423 | } | |
e97f22c9 | 424 | else |
52a11cbf RH |
425 | { |
426 | /* C++ requires that we call __cxa_begin_catch to get the | |
427 | pointer to the actual object. */ | |
428 | init = do_begin_catch (); | |
429 | } | |
430 | ||
431 | exp = create_temporary_var (ptr_type_node); | |
432 | DECL_REGISTER (exp) = 1; | |
433 | cp_finish_decl (exp, init, NULL_TREE, LOOKUP_ONLYCONVERTING); | |
434 | finish_expr_stmt (build_modify_expr (exp, INIT_EXPR, init)); | |
e97f22c9 TT |
435 | } |
436 | else | |
52a11cbf RH |
437 | finish_expr_stmt (do_begin_catch ()); |
438 | ||
439 | /* C++ requires that we call __cxa_end_catch at the end of | |
440 | processing the exception. */ | |
441 | if (! is_java) | |
442 | push_eh_cleanup (type); | |
5816cb14 | 443 | |
b35d4555 | 444 | if (decl) |
52a11cbf | 445 | initialize_handler_parm (decl, exp); |
5816cb14 | 446 | |
1a6025b4 | 447 | return type; |
5816cb14 AM |
448 | } |
449 | ||
f30432d7 | 450 | |
8d2733ca MS |
451 | /* Call this to end a catch block. Its responsible for emitting the |
452 | code to handle jumping back to the correct place, and for emitting | |
453 | the label to jump to if this catch block didn't match. */ | |
6467930b | 454 | |
824b9a4c | 455 | void |
1a6025b4 | 456 | expand_end_catch_block () |
8d08fdba | 457 | { |
f30432d7 MS |
458 | if (! doing_eh (1)) |
459 | return; | |
8d2733ca | 460 | |
0dde4175 JM |
461 | /* The exception being handled is rethrown if control reaches the end of |
462 | a handler of the function-try-block of a constructor or destructor. */ | |
463 | if (in_function_try_handler | |
464 | && (DECL_CONSTRUCTOR_P (current_function_decl) | |
465 | || DECL_DESTRUCTOR_P (current_function_decl))) | |
b35d4555 | 466 | finish_expr_stmt (build_throw (NULL_TREE)); |
8d2733ca | 467 | } |
8d08fdba | 468 | |
b35d4555 | 469 | tree |
52a11cbf | 470 | begin_eh_spec_block () |
f30432d7 | 471 | { |
52a11cbf RH |
472 | tree r = build_stmt (EH_SPEC_BLOCK, NULL_TREE, NULL_TREE); |
473 | add_stmt (r); | |
474 | return r; | |
f30432d7 MS |
475 | } |
476 | ||
b35d4555 | 477 | void |
52a11cbf RH |
478 | finish_eh_spec_block (raw_raises, eh_spec_block) |
479 | tree raw_raises; | |
480 | tree eh_spec_block; | |
f30432d7 | 481 | { |
52a11cbf | 482 | tree raises; |
0c11ada6 | 483 | |
52a11cbf | 484 | RECHAIN_STMTS (eh_spec_block, EH_SPEC_STMTS (eh_spec_block)); |
6c20b7e9 | 485 | |
52a11cbf RH |
486 | /* Strip cv quals, etc, from the specification types. */ |
487 | for (raises = NULL_TREE; | |
488 | raw_raises && TREE_VALUE (raw_raises); | |
489 | raw_raises = TREE_CHAIN (raw_raises)) | |
490 | raises = tree_cons (NULL_TREE, prepare_eh_type (TREE_VALUE (raw_raises)), | |
491 | raises); | |
6c20b7e9 | 492 | |
52a11cbf | 493 | EH_SPEC_RAISES (eh_spec_block) = raises; |
f30432d7 MS |
494 | } |
495 | ||
52a11cbf | 496 | /* Return a pointer to a buffer for an exception object of type TYPE. */ |
6467930b | 497 | |
52a11cbf RH |
498 | static tree |
499 | do_allocate_exception (type) | |
500 | tree type; | |
8d08fdba | 501 | { |
52a11cbf | 502 | tree fn; |
eb448459 | 503 | |
52a11cbf RH |
504 | fn = get_identifier ("__cxa_allocate_exception"); |
505 | if (IDENTIFIER_GLOBAL_VALUE (fn)) | |
506 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
507 | else | |
f30432d7 | 508 | { |
52a11cbf RH |
509 | /* Declare void *__cxa_allocate_exception(size_t). */ |
510 | tree tmp = tree_cons (NULL_TREE, c_size_type_node, void_list_node); | |
511 | fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp)); | |
e00737d2 | 512 | } |
52a11cbf RH |
513 | |
514 | return build_function_call (fn, tree_cons (NULL_TREE, size_in_bytes (type), | |
515 | NULL_TREE)); | |
8d08fdba MS |
516 | } |
517 | ||
2ac8a0f9 JM |
518 | #if 0 |
519 | /* Call __cxa_free_exception from a cleanup. This is never invoked | |
520 | directly. */ | |
f4a23343 | 521 | |
c6160f8f | 522 | static tree |
52a11cbf RH |
523 | do_free_exception (ptr) |
524 | tree ptr; | |
f4a23343 | 525 | { |
52a11cbf | 526 | tree fn; |
f4a23343 | 527 | |
52a11cbf | 528 | fn = get_identifier ("__cxa_free_exception"); |
f4a23343 JM |
529 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
530 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
531 | else | |
532 | { | |
52a11cbf RH |
533 | /* Declare void __cxa_free_exception (void *). */ |
534 | fn = push_void_library_fn (fn, tree_cons (NULL_TREE, ptr_type_node, | |
535 | void_list_node)); | |
f4a23343 JM |
536 | } |
537 | ||
52a11cbf | 538 | return build_function_call (fn, tree_cons (NULL_TREE, ptr, NULL_TREE)); |
f4a23343 | 539 | } |
2ac8a0f9 | 540 | #endif |
f4a23343 | 541 | |
52a11cbf | 542 | /* Build a throw expression. */ |
6467930b | 543 | |
52a11cbf RH |
544 | tree |
545 | build_throw (exp) | |
8d2733ca | 546 | tree exp; |
8d08fdba | 547 | { |
6874c264 | 548 | tree fn; |
8d08fdba | 549 | |
52a11cbf RH |
550 | if (exp == error_mark_node) |
551 | return exp; | |
552 | ||
553 | if (processing_template_decl) | |
554 | return build_min (THROW_EXPR, void_type_node, exp); | |
555 | ||
556 | if (exp == null_node) | |
557 | cp_warning ("throwing NULL, which has integral, not pointer type"); | |
558 | ||
559 | if (exp != NULL_TREE) | |
560 | { | |
561 | if (!is_admissible_throw_operand (exp)) | |
562 | return error_mark_node; | |
563 | } | |
564 | ||
8d2733ca | 565 | if (! doing_eh (1)) |
59ccf49d | 566 | return error_mark_node; |
8d08fdba | 567 | |
52a11cbf | 568 | if (exp && decl_is_java_type (TREE_TYPE (exp), 1)) |
e97f22c9 | 569 | { |
52a11cbf | 570 | tree fn = get_identifier ("_Jv_Throw"); |
e97f22c9 TT |
571 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
572 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
573 | else | |
574 | { | |
52a11cbf | 575 | /* Declare void _Jv_Throw (void *). */ |
0c11ada6 JM |
576 | tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node); |
577 | tmp = build_function_type (ptr_type_node, tmp); | |
c00996a3 | 578 | fn = push_throw_library_fn (fn, tmp); |
e97f22c9 TT |
579 | } |
580 | ||
52a11cbf | 581 | exp = build_function_call (fn, tree_cons (NULL_TREE, exp, NULL_TREE)); |
e97f22c9 TT |
582 | } |
583 | else if (exp) | |
8d2733ca | 584 | { |
faae18ab | 585 | tree throw_type; |
52a11cbf | 586 | tree cleanup; |
59ccf49d MM |
587 | tree stmt_expr; |
588 | tree compound_stmt; | |
52a11cbf RH |
589 | tree object, ptr; |
590 | tree tmp; | |
591 | ||
592 | fn = get_identifier ("__cxa_throw"); | |
593 | if (IDENTIFIER_GLOBAL_VALUE (fn)) | |
594 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
595 | else | |
596 | { | |
597 | /* The CLEANUP_TYPE is the internal type of a destructor. */ | |
598 | if (cleanup_type == NULL_TREE) | |
599 | { | |
600 | tmp = void_list_node; | |
601 | tmp = tree_cons (NULL_TREE, ptr_type_node, tmp); | |
602 | tmp = build_function_type (void_type_node, tmp); | |
603 | cleanup_type = build_pointer_type (tmp); | |
604 | } | |
605 | ||
606 | /* Declare void __cxa_throw (void*, void*, void (*)(void*)). */ | |
607 | /* ??? Second argument is supposed to be "std::type_info*". */ | |
608 | tmp = void_list_node; | |
609 | tmp = tree_cons (NULL_TREE, cleanup_type, tmp); | |
610 | tmp = tree_cons (NULL_TREE, ptr_type_node, tmp); | |
611 | tmp = tree_cons (NULL_TREE, ptr_type_node, tmp); | |
612 | tmp = build_function_type (void_type_node, tmp); | |
613 | fn = push_throw_library_fn (fn, tmp); | |
614 | } | |
59ccf49d MM |
615 | |
616 | begin_init_stmts (&stmt_expr, &compound_stmt); | |
faae18ab | 617 | |
a3b49ccd | 618 | /* throw expression */ |
e92cc029 | 619 | /* First, decay it. */ |
f30432d7 | 620 | exp = decay_conversion (exp); |
a3b49ccd | 621 | |
52a11cbf RH |
622 | /* OK, this is kind of wacky. The standard says that we call |
623 | terminate when the exception handling mechanism, after | |
624 | completing evaluation of the expression to be thrown but | |
625 | before the exception is caught (_except.throw_), calls a | |
626 | user function that exits via an uncaught exception. | |
627 | ||
628 | So we have to protect the actual initialization of the | |
629 | exception object with terminate(), but evaluate the | |
630 | expression first. Since there could be temps in the | |
631 | expression, we need to handle that, too. We also expand | |
632 | the call to __cxa_allocate_exception first (which doesn't | |
633 | matter, since it can't throw). */ | |
634 | ||
635 | my_friendly_assert (stmts_are_full_exprs_p () == 1, 19990926); | |
636 | ||
637 | /* Store the throw expression into a temp. This can be less | |
638 | efficient than storing it into the allocated space directly, but | |
639 | if we allocated the space first we would have to deal with | |
640 | cleaning it up if evaluating this expression throws. */ | |
641 | if (TREE_SIDE_EFFECTS (exp)) | |
298d6f60 | 642 | { |
52a11cbf RH |
643 | tmp = create_temporary_var (TREE_TYPE (exp)); |
644 | DECL_INITIAL (tmp) = exp; | |
645 | cp_finish_decl (tmp, exp, NULL_TREE, LOOKUP_ONLYCONVERTING); | |
646 | exp = tmp; | |
298d6f60 | 647 | } |
6874c264 | 648 | |
52a11cbf RH |
649 | /* Allocate the space for the exception. */ |
650 | ptr = create_temporary_var (ptr_type_node); | |
651 | DECL_REGISTER (ptr) = 1; | |
652 | cp_finish_decl (ptr, NULL_TREE, NULL_TREE, LOOKUP_ONLYCONVERTING); | |
653 | tmp = do_allocate_exception (TREE_TYPE (exp)); | |
654 | tmp = build_modify_expr (ptr, INIT_EXPR, tmp); | |
655 | finish_expr_stmt (tmp); | |
f4a23343 | 656 | |
52a11cbf | 657 | object = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (exp)), ptr); |
3e411c3f | 658 | object = build_indirect_ref (object, NULL); |
faae18ab | 659 | |
52a11cbf RH |
660 | exp = build_modify_expr (object, INIT_EXPR, exp); |
661 | if (exp == error_mark_node) | |
662 | error (" in thrown expression"); | |
f4a23343 | 663 | |
2ac8a0f9 | 664 | exp = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (exp), exp); |
52a11cbf | 665 | finish_expr_stmt (exp); |
72b7eeff | 666 | |
52a11cbf | 667 | throw_type = build_eh_type_type (prepare_eh_type (TREE_TYPE (object))); |
f4a23343 | 668 | |
52a11cbf RH |
669 | if (TYPE_HAS_DESTRUCTOR (TREE_TYPE (object))) |
670 | { | |
671 | cleanup = lookup_fnfields (TYPE_BINFO (TREE_TYPE (object)), | |
672 | complete_dtor_identifier, 0); | |
673 | cleanup = TREE_VALUE (cleanup); | |
674 | mark_used (cleanup); | |
675 | mark_addressable (cleanup); | |
676 | /* Pretend it's a normal function. */ | |
677 | cleanup = build1 (ADDR_EXPR, cleanup_type, cleanup); | |
f30432d7 | 678 | } |
52a11cbf | 679 | else |
6874c264 JM |
680 | { |
681 | cleanup = build_int_2 (0, 0); | |
682 | TREE_TYPE (cleanup) = cleanup_type; | |
683 | } | |
72b7eeff | 684 | |
52a11cbf RH |
685 | tmp = tree_cons (NULL_TREE, cleanup, NULL_TREE); |
686 | tmp = tree_cons (NULL_TREE, throw_type, tmp); | |
687 | tmp = tree_cons (NULL_TREE, ptr, tmp); | |
688 | tmp = build_function_call (fn, tmp); | |
689 | ||
690 | /* ??? Indicate that this function call throws throw_type. */ | |
72b7eeff | 691 | |
52a11cbf | 692 | finish_expr_stmt (tmp); |
59ccf49d MM |
693 | |
694 | exp = finish_init_stmts (stmt_expr, compound_stmt); | |
8d2733ca MS |
695 | } |
696 | else | |
a3b49ccd | 697 | { |
52a11cbf | 698 | /* Rethrow current exception. */ |
6874c264 | 699 | |
52a11cbf | 700 | tree fn = get_identifier ("__cxa_rethrow"); |
6874c264 JM |
701 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
702 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
703 | else | |
52a11cbf RH |
704 | { |
705 | /* Declare void __cxa_rethrow (void). */ | |
706 | fn = push_throw_library_fn | |
707 | (fn, build_function_type (void_type_node, void_list_node)); | |
708 | } | |
6874c264 JM |
709 | |
710 | exp = build_function_call (fn, NULL_TREE); | |
a3b49ccd | 711 | } |
8d2733ca | 712 | |
52a11cbf | 713 | exp = build1 (THROW_EXPR, void_type_node, exp); |
02020185 | 714 | |
52a11cbf | 715 | return exp; |
8d08fdba | 716 | } |
4cfbc546 NS |
717 | |
718 | /* Make sure TYPE is complete, pointer to complete, reference to | |
719 | complete, or pointer to cv void. Issue diagnostic on failure. | |
720 | Return the zero on failure and non-zero on success. FROM can be | |
721 | the expr or decl from whence TYPE came, if available. */ | |
722 | ||
723 | static int | |
724 | complete_ptr_ref_or_void_ptr_p (type, from) | |
725 | tree type; | |
726 | tree from; | |
727 | { | |
728 | int is_ptr; | |
729 | ||
730 | /* Check complete. */ | |
731 | type = complete_type_or_else (type, from); | |
732 | if (!type) | |
733 | return 0; | |
734 | ||
735 | /* Or a pointer or ref to one, or cv void *. */ | |
736 | is_ptr = TREE_CODE (type) == POINTER_TYPE; | |
737 | if (is_ptr || TREE_CODE (type) == REFERENCE_TYPE) | |
738 | { | |
739 | tree core = TREE_TYPE (type); | |
740 | ||
b72801e2 | 741 | if (is_ptr && VOID_TYPE_P (core)) |
4cfbc546 NS |
742 | /* OK */; |
743 | else if (!complete_type_or_else (core, from)) | |
744 | return 0; | |
745 | } | |
746 | return 1; | |
747 | } | |
748 | ||
d064d75a GDR |
749 | /* Return truth-value if EXPRESSION is admissible in throw-expression, |
750 | i.e. if it is not of incomplete type or a pointer/reference to such | |
751 | a type or of an abstract class type. */ | |
752 | ||
753 | static bool | |
754 | is_admissible_throw_operand (expr) | |
755 | tree expr; | |
756 | { | |
757 | tree type = TREE_TYPE (expr); | |
758 | ||
759 | /* 15.1/4 [...] The type of the throw-expression shall not be an | |
760 | incomplete type, or a pointer or a reference to an incomplete | |
761 | type, other than void*, const void*, volatile void*, or | |
762 | const volatile void*. Except for these restriction and the | |
763 | restrictions on type matching mentioned in 15.3, the operand | |
764 | of throw is treated exactly as a function argument in a call | |
765 | (5.2.2) or the operand of a return statement. */ | |
766 | if (!complete_ptr_ref_or_void_ptr_p (type, expr)) | |
767 | return false; | |
768 | ||
769 | /* 10.4/3 An abstract class shall not be used as a parameter type, | |
770 | as a function return type or as type of an explicit | |
771 | conversion. */ | |
772 | else if (CLASS_TYPE_P (type) && CLASSTYPE_PURE_VIRTUALS (type)) | |
773 | { | |
774 | cp_error ("Expression '%E' of abstract class type '%T' cannot be used in throw-expression", expr, type); | |
775 | return false; | |
776 | } | |
777 | ||
778 | return true; | |
779 | } | |
780 | ||
1660cb3a JM |
781 | /* Returns nonzero if FN is a declaration of a standard C library |
782 | function which is known not to throw. | |
783 | ||
784 | [lib.res.on.exception.handling]: None of the functions from the | |
785 | Standard C library shall report an error by throwing an | |
786 | exception, unless it calls a program-supplied function that | |
787 | throws an exception. */ | |
788 | ||
789 | #include "cfns.h" | |
790 | ||
791 | int | |
792 | nothrow_libfn_p (fn) | |
793 | tree fn; | |
794 | { | |
795 | tree id; | |
796 | ||
797 | if (TREE_PUBLIC (fn) | |
798 | && DECL_EXTERNAL (fn) | |
92643fea | 799 | && DECL_NAMESPACE_SCOPE_P (fn) |
eb68cb58 | 800 | && DECL_EXTERN_C_P (fn)) |
1660cb3a JM |
801 | /* OK */; |
802 | else | |
803 | /* Can't be a C library function. */ | |
804 | return 0; | |
805 | ||
806 | id = DECL_ASSEMBLER_NAME (fn); | |
807 | return !!libc_name_p (IDENTIFIER_POINTER (id), IDENTIFIER_LENGTH (id)); | |
808 | } | |
2bc9f1d1 JM |
809 | |
810 | /* Returns nonzero if an exception of type FROM will be caught by a | |
811 | handler for type TO, as per [except.handle]. */ | |
812 | ||
813 | static int | |
814 | can_convert_eh (to, from) | |
815 | tree to, from; | |
816 | { | |
817 | if (TREE_CODE (to) == REFERENCE_TYPE) | |
818 | to = TREE_TYPE (to); | |
819 | if (TREE_CODE (from) == REFERENCE_TYPE) | |
820 | from = TREE_TYPE (from); | |
821 | ||
822 | if (TREE_CODE (to) == POINTER_TYPE && TREE_CODE (from) == POINTER_TYPE) | |
823 | { | |
824 | to = TREE_TYPE (to); | |
825 | from = TREE_TYPE (from); | |
826 | ||
827 | if (! at_least_as_qualified_p (to, from)) | |
828 | return 0; | |
829 | ||
830 | if (TREE_CODE (to) == VOID_TYPE) | |
831 | return 1; | |
832 | ||
833 | /* else fall through */ | |
834 | } | |
835 | ||
2d46ec83 | 836 | if (CLASS_TYPE_P (to) && CLASS_TYPE_P (from) |
2bc9f1d1 JM |
837 | && PUBLICLY_UNIQUELY_DERIVED_P (to, from)) |
838 | return 1; | |
839 | ||
840 | return 0; | |
841 | } | |
842 | ||
843 | /* Check whether any of HANDLERS are shadowed by another handler accepting | |
844 | TYPE. Note that the shadowing may not be complete; even if an exception | |
845 | of type B would be caught by a handler for A, there could be a derived | |
846 | class C for which A is an ambiguous base but B is not, so the handler | |
847 | for B would catch an exception of type C. */ | |
848 | ||
849 | static void | |
850 | check_handlers_1 (master, handlers) | |
851 | tree master; | |
852 | tree handlers; | |
853 | { | |
854 | tree type = TREE_TYPE (master); | |
855 | tree handler; | |
856 | ||
857 | for (handler = handlers; handler; handler = TREE_CHAIN (handler)) | |
858 | if (TREE_TYPE (handler) | |
859 | && can_convert_eh (type, TREE_TYPE (handler))) | |
860 | { | |
861 | lineno = STMT_LINENO (handler); | |
862 | cp_warning ("exception of type `%T' will be caught", | |
863 | TREE_TYPE (handler)); | |
864 | lineno = STMT_LINENO (master); | |
865 | cp_warning (" by earlier handler for `%T'", type); | |
866 | break; | |
867 | } | |
868 | } | |
869 | ||
870 | /* Given a chain of HANDLERs, make sure that they're OK. */ | |
871 | ||
872 | void | |
873 | check_handlers (handlers) | |
874 | tree handlers; | |
875 | { | |
876 | tree handler; | |
877 | int save_line = lineno; | |
878 | for (handler = handlers; handler; handler = TREE_CHAIN (handler)) | |
879 | { | |
880 | if (TREE_CHAIN (handler) == NULL_TREE) | |
881 | /* No more handlers; nothing to shadow. */; | |
882 | else if (TREE_TYPE (handler) == NULL_TREE) | |
883 | { | |
884 | lineno = STMT_LINENO (handler); | |
885 | cp_pedwarn | |
886 | ("`...' handler must be the last handler for its try block"); | |
887 | } | |
888 | else | |
889 | check_handlers_1 (handler, TREE_CHAIN (handler)); | |
890 | } | |
891 | lineno = save_line; | |
892 | } |