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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)); | |
46 | static void choose_personality_routine PARAMS ((bool)); | |
47 | static void initialize_handler_parm PARAMS ((tree, tree)); | |
48 | static tree do_allocate_exception PARAMS ((tree)); | |
158991b7 | 49 | static int complete_ptr_ref_or_void_ptr_p PARAMS ((tree, tree)); |
d064d75a | 50 | static bool is_admissible_throw_operand PARAMS ((tree)); |
fbd40359 ZW |
51 | static int can_convert_eh PARAMS ((tree, tree)); |
52 | static void check_handlers_1 PARAMS ((tree, tree)); | |
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 | ||
2c73f9f5 | 65 | if (flag_honor_std) |
6bcedb4e | 66 | push_namespace (std_identifier); |
52a11cbf RH |
67 | |
68 | /* void std::terminate (); */ | |
69 | tmp = build_function_type (void_type_node, void_list_node); | |
70 | terminate_node = build_cp_library_fn_ptr ("terminate", tmp); | |
9cd64686 | 71 | TREE_THIS_VOLATILE (terminate_node) = 1; |
0c11ada6 | 72 | TREE_NOTHROW (terminate_node) = 1; |
2c73f9f5 ML |
73 | if (flag_honor_std) |
74 | pop_namespace (); | |
8ccc31eb | 75 | |
52a11cbf | 76 | protect_cleanup_actions = build_call (terminate_node, NULL_TREE); |
6874c264 | 77 | |
52a11cbf RH |
78 | /* void __cxa_call_unexpected(void *); */ |
79 | tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node); | |
80 | tmp = build_function_type (void_type_node, tmp); | |
81 | call_unexpected_node | |
82 | = push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp); | |
6874c264 | 83 | |
52a11cbf RH |
84 | eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS |
85 | ? "__gxx_personality_sj0" | |
86 | : "__gxx_personality_v0"); | |
6874c264 | 87 | |
52a11cbf | 88 | lang_eh_runtime_type = build_eh_type_type; |
6874c264 JM |
89 | } |
90 | ||
6874c264 | 91 | static tree |
52a11cbf | 92 | prepare_eh_type (type) |
f30432d7 | 93 | tree type; |
8d08fdba | 94 | { |
52a11cbf RH |
95 | if (type == NULL_TREE) |
96 | return type; | |
f30432d7 MS |
97 | if (type == error_mark_node) |
98 | return error_mark_node; | |
8d2733ca | 99 | |
e92cc029 | 100 | /* peel back references, so they match. */ |
f30432d7 MS |
101 | if (TREE_CODE (type) == REFERENCE_TYPE) |
102 | type = TREE_TYPE (type); | |
8d08fdba | 103 | |
e92cc029 | 104 | /* Peel off cv qualifiers. */ |
f30432d7 | 105 | type = TYPE_MAIN_VARIANT (type); |
8d2733ca | 106 | |
52a11cbf | 107 | return type; |
8d08fdba | 108 | } |
8d08fdba | 109 | |
e5f614d7 | 110 | /* Build the address of a typeinfo decl for use in the runtime |
52a11cbf | 111 | matching field of the exception model. */ |
5816cb14 AM |
112 | |
113 | static tree | |
52a11cbf | 114 | build_eh_type_type (type) |
5816cb14 AM |
115 | tree type; |
116 | { | |
5816cb14 | 117 | tree exp; |
5816cb14 | 118 | |
93ca4ba7 JM |
119 | if (type == NULL_TREE || type == error_mark_node) |
120 | return type; | |
5816cb14 | 121 | |
52a11cbf RH |
122 | if (decl_is_java_type (type, 0)) |
123 | exp = build_java_class_ref (TREE_TYPE (type)); | |
124 | else | |
125 | exp = get_tinfo_decl (type); | |
5816cb14 | 126 | |
e5f614d7 | 127 | mark_used (exp); |
db48b831 | 128 | exp = build1 (ADDR_EXPR, ptr_type_node, exp); |
5816cb14 | 129 | |
52a11cbf | 130 | return exp; |
5816cb14 AM |
131 | } |
132 | ||
52a11cbf RH |
133 | tree |
134 | build_exc_ptr () | |
135 | { | |
136 | return build (EXC_PTR_EXPR, ptr_type_node); | |
137 | } | |
138 | ||
139 | /* Build up a call to __cxa_begin_catch, to tell the runtime that the | |
140 | exception has been handled. */ | |
93ca4ba7 | 141 | |
52a11cbf RH |
142 | static tree |
143 | do_begin_catch () | |
9c606f69 | 144 | { |
52a11cbf RH |
145 | tree fn; |
146 | ||
147 | fn = get_identifier ("__cxa_begin_catch"); | |
148 | if (IDENTIFIER_GLOBAL_VALUE (fn)) | |
149 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
150 | else | |
9c606f69 | 151 | { |
52a11cbf RH |
152 | /* Declare void* __cxa_begin_catch (void *). */ |
153 | tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node); | |
154 | fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp)); | |
9c606f69 | 155 | } |
52a11cbf RH |
156 | |
157 | return build_function_call (fn, tree_cons (NULL_TREE, build_exc_ptr (), | |
158 | NULL_TREE)); | |
9c606f69 AM |
159 | } |
160 | ||
93ca4ba7 JM |
161 | /* Returns nonzero if cleaning up an exception of type TYPE (which can be |
162 | NULL_TREE for a ... handler) will not throw an exception. */ | |
163 | ||
164 | static int | |
165 | dtor_nothrow (type) | |
166 | tree type; | |
167 | { | |
168 | tree fn; | |
169 | ||
170 | if (type == NULL_TREE) | |
171 | return 0; | |
172 | ||
173 | if (! TYPE_HAS_DESTRUCTOR (type)) | |
174 | return 1; | |
175 | ||
176 | fn = lookup_member (type, dtor_identifier, 0, 0); | |
177 | fn = TREE_VALUE (fn); | |
178 | return TREE_NOTHROW (fn); | |
179 | } | |
180 | ||
52a11cbf | 181 | /* Build up a call to __cxa_end_catch, to destroy the exception object |
93ca4ba7 | 182 | for the current catch block if no others are currently using it. */ |
6467930b | 183 | |
c7ae64f2 | 184 | static tree |
52a11cbf | 185 | do_end_catch (type) |
93ca4ba7 | 186 | tree type; |
72b7eeff | 187 | { |
6874c264 | 188 | tree fn, cleanup; |
52a11cbf RH |
189 | |
190 | fn = get_identifier ("__cxa_end_catch"); | |
6874c264 JM |
191 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
192 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
193 | else | |
194 | { | |
52a11cbf RH |
195 | /* Declare void __cxa_end_catch (). */ |
196 | fn = push_void_library_fn (fn, void_list_node); | |
0c11ada6 JM |
197 | /* This can throw if the destructor for the exception throws. */ |
198 | TREE_NOTHROW (fn) = 0; | |
6874c264 | 199 | } |
72b7eeff | 200 | |
52a11cbf | 201 | cleanup = build_function_call (fn, NULL_TREE); |
93ca4ba7 | 202 | TREE_NOTHROW (cleanup) = dtor_nothrow (type); |
52a11cbf | 203 | |
c0700ea5 | 204 | return cleanup; |
c7ae64f2 JM |
205 | } |
206 | ||
207 | /* This routine creates the cleanup for the current exception. */ | |
72b7eeff | 208 | |
c7ae64f2 | 209 | static void |
93ca4ba7 JM |
210 | push_eh_cleanup (type) |
211 | tree type; | |
c7ae64f2 | 212 | { |
52a11cbf | 213 | finish_decl_cleanup (NULL_TREE, do_end_catch (type)); |
f4a23343 JM |
214 | } |
215 | ||
e97f22c9 TT |
216 | /* Return nonzero value if DECL is a Java type suitable for catch or |
217 | throw. */ | |
218 | ||
52a11cbf | 219 | static bool |
e97f22c9 TT |
220 | decl_is_java_type (decl, err) |
221 | tree decl; | |
222 | int err; | |
223 | { | |
52a11cbf RH |
224 | bool r = (TREE_CODE (decl) == POINTER_TYPE |
225 | && TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE | |
226 | && TYPE_FOR_JAVA (TREE_TYPE (decl))); | |
e97f22c9 TT |
227 | |
228 | if (err) | |
229 | { | |
230 | if (TREE_CODE (decl) == REFERENCE_TYPE | |
231 | && TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE | |
232 | && TYPE_FOR_JAVA (TREE_TYPE (decl))) | |
233 | { | |
234 | /* Can't throw a reference. */ | |
235 | cp_error ("type `%T' is disallowed in Java `throw' or `catch'", | |
236 | decl); | |
237 | } | |
238 | ||
239 | if (r) | |
240 | { | |
241 | tree jthrow_node | |
242 | = IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable")); | |
400500c4 | 243 | |
e97f22c9 | 244 | if (jthrow_node == NULL_TREE) |
400500c4 RK |
245 | fatal_error |
246 | ("call to Java `catch' or `throw' with `jthrowable' undefined"); | |
247 | ||
e97f22c9 TT |
248 | jthrow_node = TREE_TYPE (TREE_TYPE (jthrow_node)); |
249 | ||
250 | if (! DERIVED_FROM_P (jthrow_node, TREE_TYPE (decl))) | |
251 | { | |
252 | /* Thrown object must be a Throwable. */ | |
253 | cp_error ("type `%T' is not derived from `java::lang::Throwable'", | |
254 | TREE_TYPE (decl)); | |
255 | } | |
256 | } | |
257 | } | |
258 | ||
259 | return r; | |
260 | } | |
261 | ||
52a11cbf RH |
262 | static void |
263 | choose_personality_routine (is_java) | |
264 | bool is_java; | |
265 | { | |
266 | static enum { | |
267 | chose_none, | |
268 | chose_cpp, | |
269 | chose_java, | |
270 | gave_error | |
271 | } state; | |
272 | ||
273 | switch (state) | |
274 | { | |
275 | case chose_none: | |
276 | /* We defaulted to C++ in init_exception_processing. | |
277 | Reconfigure for Java if we changed our minds. */ | |
278 | if (is_java) | |
279 | eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS | |
280 | ? "__gcj_personality_sj0" | |
281 | : "__gcj_personality_v0"); | |
282 | state = (is_java ? chose_java : chose_cpp); | |
283 | break; | |
284 | ||
285 | case chose_cpp: | |
286 | case chose_java: | |
287 | if (state != (is_java ? chose_java : chose_cpp)) | |
288 | { | |
289 | error ("mixing C++ and Java catches in a single translation unit"); | |
290 | state = gave_error; | |
291 | } | |
292 | break; | |
293 | ||
294 | case gave_error: | |
295 | break; | |
296 | } | |
297 | } | |
298 | ||
b35d4555 | 299 | /* Initialize the catch parameter DECL. */ |
6467930b | 300 | |
b35d4555 | 301 | static void |
52a11cbf | 302 | initialize_handler_parm (decl, exp) |
3c5c0849 | 303 | tree decl; |
52a11cbf | 304 | tree exp; |
8d08fdba | 305 | { |
b35d4555 MM |
306 | tree init; |
307 | tree init_type; | |
308 | ||
309 | /* Make sure we mark the catch param as used, otherwise we'll get a | |
310 | warning about an unused ((anonymous)). */ | |
311 | TREE_USED (decl) = 1; | |
312 | ||
52a11cbf RH |
313 | /* Figure out the type that the initializer is. Pointers are returned |
314 | adjusted by value from __cxa_begin_catch. Others are returned by | |
315 | reference. */ | |
b35d4555 | 316 | init_type = TREE_TYPE (decl); |
52a11cbf RH |
317 | if (TREE_CODE (init_type) != POINTER_TYPE |
318 | && TREE_CODE (init_type) != REFERENCE_TYPE) | |
b35d4555 MM |
319 | init_type = build_reference_type (init_type); |
320 | ||
52a11cbf | 321 | choose_personality_routine (decl_is_java_type (init_type, 0)); |
b35d4555 MM |
322 | |
323 | /* Since pointers are passed by value, initialize a reference to | |
52a11cbf | 324 | pointer catch parm with the address of the temporary. */ |
b35d4555 MM |
325 | if (TREE_CODE (init_type) == REFERENCE_TYPE |
326 | && TREE_CODE (TREE_TYPE (init_type)) == POINTER_TYPE) | |
327 | exp = build_unary_op (ADDR_EXPR, exp, 1); | |
328 | ||
52a11cbf | 329 | exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0); |
b35d4555 MM |
330 | |
331 | init = convert_from_reference (exp); | |
332 | ||
333 | /* If the constructor for the catch parm exits via an exception, we | |
334 | must call terminate. See eh23.C. */ | |
335 | if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl))) | |
faf5394a | 336 | { |
b35d4555 MM |
337 | /* Generate the copy constructor call directly so we can wrap it. |
338 | See also expand_default_init. */ | |
339 | init = ocp_convert (TREE_TYPE (decl), init, | |
340 | CONV_IMPLICIT|CONV_FORCE_TEMP, 0); | |
52a11cbf | 341 | init = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (init), init); |
faf5394a MS |
342 | } |
343 | ||
b35d4555 MM |
344 | /* Let `cp_finish_decl' know that this initializer is ok. */ |
345 | DECL_INITIAL (decl) = error_mark_node; | |
346 | decl = pushdecl (decl); | |
8d2733ca | 347 | |
b35d4555 | 348 | start_decl_1 (decl); |
cd9f6678 | 349 | cp_finish_decl (decl, init, NULL_TREE, |
b35d4555 | 350 | LOOKUP_ONLYCONVERTING|DIRECT_BIND); |
5816cb14 AM |
351 | } |
352 | ||
b35d4555 | 353 | /* Call this to start a catch block. DECL is the catch parameter. */ |
5816cb14 | 354 | |
b35d4555 MM |
355 | tree |
356 | expand_start_catch_block (decl) | |
3c5c0849 | 357 | tree decl; |
5816cb14 | 358 | { |
b35d4555 MM |
359 | tree compound_stmt_1; |
360 | tree compound_stmt_2; | |
52a11cbf RH |
361 | tree exp = NULL_TREE; |
362 | tree type; | |
363 | bool is_java; | |
5816cb14 | 364 | |
b35d4555 MM |
365 | if (! doing_eh (1)) |
366 | return NULL_TREE; | |
5816cb14 | 367 | |
b35d4555 | 368 | /* Make sure this declaration is reasonable. */ |
3c5c0849 MM |
369 | if (decl && !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl), NULL_TREE)) |
370 | decl = NULL_TREE; | |
5816cb14 | 371 | |
b35d4555 MM |
372 | /* Create a binding level for the eh_info and the exception object |
373 | cleanup. */ | |
374 | compound_stmt_1 = begin_compound_stmt (/*has_no_scope=*/0); | |
826840d9 | 375 | note_level_for_catch (); |
b35d4555 | 376 | |
52a11cbf RH |
377 | if (decl) |
378 | type = prepare_eh_type (TREE_TYPE (decl)); | |
379 | else | |
380 | type = NULL_TREE; | |
381 | begin_catch_block (type); | |
382 | ||
383 | is_java = false; | |
384 | if (decl) | |
e97f22c9 | 385 | { |
52a11cbf | 386 | tree init; |
5816cb14 | 387 | |
52a11cbf RH |
388 | if (decl_is_java_type (type, 1)) |
389 | { | |
390 | /* Java only passes object via pointer and doesn't require | |
391 | adjusting. The java object is immediately before the | |
392 | generic exception header. */ | |
393 | init = build_exc_ptr (); | |
394 | init = build1 (NOP_EXPR, build_pointer_type (type), init); | |
395 | init = build (MINUS_EXPR, TREE_TYPE (init), init, | |
396 | TYPE_SIZE_UNIT (TREE_TYPE (init))); | |
3e411c3f | 397 | init = build_indirect_ref (init, NULL); |
52a11cbf RH |
398 | is_java = true; |
399 | } | |
e97f22c9 | 400 | else |
52a11cbf RH |
401 | { |
402 | /* C++ requires that we call __cxa_begin_catch to get the | |
403 | pointer to the actual object. */ | |
404 | init = do_begin_catch (); | |
405 | } | |
406 | ||
407 | exp = create_temporary_var (ptr_type_node); | |
408 | DECL_REGISTER (exp) = 1; | |
409 | cp_finish_decl (exp, init, NULL_TREE, LOOKUP_ONLYCONVERTING); | |
410 | finish_expr_stmt (build_modify_expr (exp, INIT_EXPR, init)); | |
e97f22c9 TT |
411 | } |
412 | else | |
52a11cbf RH |
413 | finish_expr_stmt (do_begin_catch ()); |
414 | ||
415 | /* C++ requires that we call __cxa_end_catch at the end of | |
416 | processing the exception. */ | |
417 | if (! is_java) | |
418 | push_eh_cleanup (type); | |
5816cb14 | 419 | |
b35d4555 MM |
420 | /* Create a binding level for the parm. */ |
421 | compound_stmt_2 = begin_compound_stmt (/*has_no_scope=*/0); | |
5816cb14 | 422 | |
b35d4555 | 423 | if (decl) |
52a11cbf | 424 | initialize_handler_parm (decl, exp); |
5816cb14 | 425 | |
b35d4555 | 426 | return build_tree_list (compound_stmt_1, compound_stmt_2); |
5816cb14 AM |
427 | } |
428 | ||
f30432d7 | 429 | |
8d2733ca MS |
430 | /* Call this to end a catch block. Its responsible for emitting the |
431 | code to handle jumping back to the correct place, and for emitting | |
432 | the label to jump to if this catch block didn't match. */ | |
6467930b | 433 | |
824b9a4c | 434 | void |
b35d4555 MM |
435 | expand_end_catch_block (blocks) |
436 | tree blocks; | |
8d08fdba | 437 | { |
b35d4555 MM |
438 | tree compound_stmt_1 = blocks ? TREE_PURPOSE (blocks): NULL_TREE; |
439 | tree compound_stmt_2 = blocks ? TREE_VALUE (blocks): NULL_TREE; | |
440 | ||
f30432d7 MS |
441 | if (! doing_eh (1)) |
442 | return; | |
8d2733ca | 443 | |
0dde4175 JM |
444 | /* The exception being handled is rethrown if control reaches the end of |
445 | a handler of the function-try-block of a constructor or destructor. */ | |
446 | if (in_function_try_handler | |
447 | && (DECL_CONSTRUCTOR_P (current_function_decl) | |
448 | || DECL_DESTRUCTOR_P (current_function_decl))) | |
b35d4555 | 449 | finish_expr_stmt (build_throw (NULL_TREE)); |
0dde4175 | 450 | |
c7ae64f2 | 451 | /* Cleanup the EH parameter. */ |
b35d4555 | 452 | finish_compound_stmt (/*has_no_scope=*/0, compound_stmt_2); |
46e8c075 | 453 | /* Cleanup the EH object. */ |
4a6ef811 | 454 | finish_compound_stmt (/*has_no_scope=*/0, compound_stmt_1); |
8d2733ca | 455 | } |
8d08fdba | 456 | |
b35d4555 | 457 | tree |
52a11cbf | 458 | begin_eh_spec_block () |
f30432d7 | 459 | { |
52a11cbf RH |
460 | tree r = build_stmt (EH_SPEC_BLOCK, NULL_TREE, NULL_TREE); |
461 | add_stmt (r); | |
462 | return r; | |
f30432d7 MS |
463 | } |
464 | ||
b35d4555 | 465 | void |
52a11cbf RH |
466 | finish_eh_spec_block (raw_raises, eh_spec_block) |
467 | tree raw_raises; | |
468 | tree eh_spec_block; | |
f30432d7 | 469 | { |
52a11cbf | 470 | tree raises; |
0c11ada6 | 471 | |
52a11cbf | 472 | RECHAIN_STMTS (eh_spec_block, EH_SPEC_STMTS (eh_spec_block)); |
6c20b7e9 | 473 | |
52a11cbf RH |
474 | /* Strip cv quals, etc, from the specification types. */ |
475 | for (raises = NULL_TREE; | |
476 | raw_raises && TREE_VALUE (raw_raises); | |
477 | raw_raises = TREE_CHAIN (raw_raises)) | |
478 | raises = tree_cons (NULL_TREE, prepare_eh_type (TREE_VALUE (raw_raises)), | |
479 | raises); | |
6c20b7e9 | 480 | |
52a11cbf | 481 | EH_SPEC_RAISES (eh_spec_block) = raises; |
f30432d7 MS |
482 | } |
483 | ||
52a11cbf | 484 | /* Return a pointer to a buffer for an exception object of type TYPE. */ |
6467930b | 485 | |
52a11cbf RH |
486 | static tree |
487 | do_allocate_exception (type) | |
488 | tree type; | |
8d08fdba | 489 | { |
52a11cbf | 490 | tree fn; |
eb448459 | 491 | |
52a11cbf RH |
492 | fn = get_identifier ("__cxa_allocate_exception"); |
493 | if (IDENTIFIER_GLOBAL_VALUE (fn)) | |
494 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
495 | else | |
f30432d7 | 496 | { |
52a11cbf RH |
497 | /* Declare void *__cxa_allocate_exception(size_t). */ |
498 | tree tmp = tree_cons (NULL_TREE, c_size_type_node, void_list_node); | |
499 | fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp)); | |
e00737d2 | 500 | } |
52a11cbf RH |
501 | |
502 | return build_function_call (fn, tree_cons (NULL_TREE, size_in_bytes (type), | |
503 | NULL_TREE)); | |
8d08fdba MS |
504 | } |
505 | ||
2ac8a0f9 JM |
506 | #if 0 |
507 | /* Call __cxa_free_exception from a cleanup. This is never invoked | |
508 | directly. */ | |
f4a23343 | 509 | |
c6160f8f | 510 | static tree |
52a11cbf RH |
511 | do_free_exception (ptr) |
512 | tree ptr; | |
f4a23343 | 513 | { |
52a11cbf | 514 | tree fn; |
f4a23343 | 515 | |
52a11cbf | 516 | fn = get_identifier ("__cxa_free_exception"); |
f4a23343 JM |
517 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
518 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
519 | else | |
520 | { | |
52a11cbf RH |
521 | /* Declare void __cxa_free_exception (void *). */ |
522 | fn = push_void_library_fn (fn, tree_cons (NULL_TREE, ptr_type_node, | |
523 | void_list_node)); | |
f4a23343 JM |
524 | } |
525 | ||
52a11cbf | 526 | return build_function_call (fn, tree_cons (NULL_TREE, ptr, NULL_TREE)); |
f4a23343 | 527 | } |
2ac8a0f9 | 528 | #endif |
f4a23343 | 529 | |
52a11cbf | 530 | /* Build a throw expression. */ |
6467930b | 531 | |
52a11cbf RH |
532 | tree |
533 | build_throw (exp) | |
8d2733ca | 534 | tree exp; |
8d08fdba | 535 | { |
6874c264 | 536 | tree fn; |
8d08fdba | 537 | |
52a11cbf RH |
538 | if (exp == error_mark_node) |
539 | return exp; | |
540 | ||
541 | if (processing_template_decl) | |
542 | return build_min (THROW_EXPR, void_type_node, exp); | |
543 | ||
544 | if (exp == null_node) | |
545 | cp_warning ("throwing NULL, which has integral, not pointer type"); | |
546 | ||
547 | if (exp != NULL_TREE) | |
548 | { | |
549 | if (!is_admissible_throw_operand (exp)) | |
550 | return error_mark_node; | |
551 | } | |
552 | ||
8d2733ca | 553 | if (! doing_eh (1)) |
59ccf49d | 554 | return error_mark_node; |
8d08fdba | 555 | |
52a11cbf | 556 | if (exp && decl_is_java_type (TREE_TYPE (exp), 1)) |
e97f22c9 | 557 | { |
52a11cbf | 558 | tree fn = get_identifier ("_Jv_Throw"); |
e97f22c9 TT |
559 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
560 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
561 | else | |
562 | { | |
52a11cbf | 563 | /* Declare void _Jv_Throw (void *). */ |
0c11ada6 JM |
564 | tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node); |
565 | tmp = build_function_type (ptr_type_node, tmp); | |
c00996a3 | 566 | fn = push_throw_library_fn (fn, tmp); |
e97f22c9 TT |
567 | } |
568 | ||
52a11cbf | 569 | exp = build_function_call (fn, tree_cons (NULL_TREE, exp, NULL_TREE)); |
e97f22c9 TT |
570 | } |
571 | else if (exp) | |
8d2733ca | 572 | { |
faae18ab | 573 | tree throw_type; |
52a11cbf | 574 | tree cleanup; |
59ccf49d MM |
575 | tree stmt_expr; |
576 | tree compound_stmt; | |
52a11cbf RH |
577 | tree object, ptr; |
578 | tree tmp; | |
579 | ||
580 | fn = get_identifier ("__cxa_throw"); | |
581 | if (IDENTIFIER_GLOBAL_VALUE (fn)) | |
582 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
583 | else | |
584 | { | |
585 | /* The CLEANUP_TYPE is the internal type of a destructor. */ | |
586 | if (cleanup_type == NULL_TREE) | |
587 | { | |
588 | tmp = void_list_node; | |
589 | tmp = tree_cons (NULL_TREE, ptr_type_node, tmp); | |
590 | tmp = build_function_type (void_type_node, tmp); | |
591 | cleanup_type = build_pointer_type (tmp); | |
592 | } | |
593 | ||
594 | /* Declare void __cxa_throw (void*, void*, void (*)(void*)). */ | |
595 | /* ??? Second argument is supposed to be "std::type_info*". */ | |
596 | tmp = void_list_node; | |
597 | tmp = tree_cons (NULL_TREE, cleanup_type, tmp); | |
598 | tmp = tree_cons (NULL_TREE, ptr_type_node, tmp); | |
599 | tmp = tree_cons (NULL_TREE, ptr_type_node, tmp); | |
600 | tmp = build_function_type (void_type_node, tmp); | |
601 | fn = push_throw_library_fn (fn, tmp); | |
602 | } | |
59ccf49d MM |
603 | |
604 | begin_init_stmts (&stmt_expr, &compound_stmt); | |
faae18ab | 605 | |
a3b49ccd | 606 | /* throw expression */ |
e92cc029 | 607 | /* First, decay it. */ |
f30432d7 | 608 | exp = decay_conversion (exp); |
a3b49ccd | 609 | |
52a11cbf RH |
610 | /* OK, this is kind of wacky. The standard says that we call |
611 | terminate when the exception handling mechanism, after | |
612 | completing evaluation of the expression to be thrown but | |
613 | before the exception is caught (_except.throw_), calls a | |
614 | user function that exits via an uncaught exception. | |
615 | ||
616 | So we have to protect the actual initialization of the | |
617 | exception object with terminate(), but evaluate the | |
618 | expression first. Since there could be temps in the | |
619 | expression, we need to handle that, too. We also expand | |
620 | the call to __cxa_allocate_exception first (which doesn't | |
621 | matter, since it can't throw). */ | |
622 | ||
623 | my_friendly_assert (stmts_are_full_exprs_p () == 1, 19990926); | |
624 | ||
625 | /* Store the throw expression into a temp. This can be less | |
626 | efficient than storing it into the allocated space directly, but | |
627 | if we allocated the space first we would have to deal with | |
628 | cleaning it up if evaluating this expression throws. */ | |
629 | if (TREE_SIDE_EFFECTS (exp)) | |
298d6f60 | 630 | { |
52a11cbf RH |
631 | tmp = create_temporary_var (TREE_TYPE (exp)); |
632 | DECL_INITIAL (tmp) = exp; | |
633 | cp_finish_decl (tmp, exp, NULL_TREE, LOOKUP_ONLYCONVERTING); | |
634 | exp = tmp; | |
298d6f60 | 635 | } |
6874c264 | 636 | |
52a11cbf RH |
637 | /* Allocate the space for the exception. */ |
638 | ptr = create_temporary_var (ptr_type_node); | |
639 | DECL_REGISTER (ptr) = 1; | |
640 | cp_finish_decl (ptr, NULL_TREE, NULL_TREE, LOOKUP_ONLYCONVERTING); | |
641 | tmp = do_allocate_exception (TREE_TYPE (exp)); | |
642 | tmp = build_modify_expr (ptr, INIT_EXPR, tmp); | |
643 | finish_expr_stmt (tmp); | |
f4a23343 | 644 | |
52a11cbf | 645 | object = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (exp)), ptr); |
3e411c3f | 646 | object = build_indirect_ref (object, NULL); |
faae18ab | 647 | |
52a11cbf RH |
648 | exp = build_modify_expr (object, INIT_EXPR, exp); |
649 | if (exp == error_mark_node) | |
650 | error (" in thrown expression"); | |
f4a23343 | 651 | |
2ac8a0f9 | 652 | exp = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (exp), exp); |
52a11cbf | 653 | finish_expr_stmt (exp); |
72b7eeff | 654 | |
52a11cbf | 655 | throw_type = build_eh_type_type (prepare_eh_type (TREE_TYPE (object))); |
f4a23343 | 656 | |
52a11cbf RH |
657 | if (TYPE_HAS_DESTRUCTOR (TREE_TYPE (object))) |
658 | { | |
659 | cleanup = lookup_fnfields (TYPE_BINFO (TREE_TYPE (object)), | |
660 | complete_dtor_identifier, 0); | |
661 | cleanup = TREE_VALUE (cleanup); | |
662 | mark_used (cleanup); | |
663 | mark_addressable (cleanup); | |
664 | /* Pretend it's a normal function. */ | |
665 | cleanup = build1 (ADDR_EXPR, cleanup_type, cleanup); | |
f30432d7 | 666 | } |
52a11cbf | 667 | else |
6874c264 JM |
668 | { |
669 | cleanup = build_int_2 (0, 0); | |
670 | TREE_TYPE (cleanup) = cleanup_type; | |
671 | } | |
72b7eeff | 672 | |
52a11cbf RH |
673 | tmp = tree_cons (NULL_TREE, cleanup, NULL_TREE); |
674 | tmp = tree_cons (NULL_TREE, throw_type, tmp); | |
675 | tmp = tree_cons (NULL_TREE, ptr, tmp); | |
676 | tmp = build_function_call (fn, tmp); | |
677 | ||
678 | /* ??? Indicate that this function call throws throw_type. */ | |
72b7eeff | 679 | |
52a11cbf | 680 | finish_expr_stmt (tmp); |
59ccf49d MM |
681 | |
682 | exp = finish_init_stmts (stmt_expr, compound_stmt); | |
8d2733ca MS |
683 | } |
684 | else | |
a3b49ccd | 685 | { |
52a11cbf | 686 | /* Rethrow current exception. */ |
6874c264 | 687 | |
52a11cbf | 688 | tree fn = get_identifier ("__cxa_rethrow"); |
6874c264 JM |
689 | if (IDENTIFIER_GLOBAL_VALUE (fn)) |
690 | fn = IDENTIFIER_GLOBAL_VALUE (fn); | |
691 | else | |
52a11cbf RH |
692 | { |
693 | /* Declare void __cxa_rethrow (void). */ | |
694 | fn = push_throw_library_fn | |
695 | (fn, build_function_type (void_type_node, void_list_node)); | |
696 | } | |
6874c264 JM |
697 | |
698 | exp = build_function_call (fn, NULL_TREE); | |
a3b49ccd | 699 | } |
8d2733ca | 700 | |
52a11cbf | 701 | exp = build1 (THROW_EXPR, void_type_node, exp); |
02020185 | 702 | |
52a11cbf | 703 | return exp; |
8d08fdba | 704 | } |
4cfbc546 NS |
705 | |
706 | /* Make sure TYPE is complete, pointer to complete, reference to | |
707 | complete, or pointer to cv void. Issue diagnostic on failure. | |
708 | Return the zero on failure and non-zero on success. FROM can be | |
709 | the expr or decl from whence TYPE came, if available. */ | |
710 | ||
711 | static int | |
712 | complete_ptr_ref_or_void_ptr_p (type, from) | |
713 | tree type; | |
714 | tree from; | |
715 | { | |
716 | int is_ptr; | |
717 | ||
718 | /* Check complete. */ | |
719 | type = complete_type_or_else (type, from); | |
720 | if (!type) | |
721 | return 0; | |
722 | ||
723 | /* Or a pointer or ref to one, or cv void *. */ | |
724 | is_ptr = TREE_CODE (type) == POINTER_TYPE; | |
725 | if (is_ptr || TREE_CODE (type) == REFERENCE_TYPE) | |
726 | { | |
727 | tree core = TREE_TYPE (type); | |
728 | ||
b72801e2 | 729 | if (is_ptr && VOID_TYPE_P (core)) |
4cfbc546 NS |
730 | /* OK */; |
731 | else if (!complete_type_or_else (core, from)) | |
732 | return 0; | |
733 | } | |
734 | return 1; | |
735 | } | |
736 | ||
d064d75a GDR |
737 | /* Return truth-value if EXPRESSION is admissible in throw-expression, |
738 | i.e. if it is not of incomplete type or a pointer/reference to such | |
739 | a type or of an abstract class type. */ | |
740 | ||
741 | static bool | |
742 | is_admissible_throw_operand (expr) | |
743 | tree expr; | |
744 | { | |
745 | tree type = TREE_TYPE (expr); | |
746 | ||
747 | /* 15.1/4 [...] The type of the throw-expression shall not be an | |
748 | incomplete type, or a pointer or a reference to an incomplete | |
749 | type, other than void*, const void*, volatile void*, or | |
750 | const volatile void*. Except for these restriction and the | |
751 | restrictions on type matching mentioned in 15.3, the operand | |
752 | of throw is treated exactly as a function argument in a call | |
753 | (5.2.2) or the operand of a return statement. */ | |
754 | if (!complete_ptr_ref_or_void_ptr_p (type, expr)) | |
755 | return false; | |
756 | ||
757 | /* 10.4/3 An abstract class shall not be used as a parameter type, | |
758 | as a function return type or as type of an explicit | |
759 | conversion. */ | |
760 | else if (CLASS_TYPE_P (type) && CLASSTYPE_PURE_VIRTUALS (type)) | |
761 | { | |
762 | cp_error ("Expression '%E' of abstract class type '%T' cannot be used in throw-expression", expr, type); | |
763 | return false; | |
764 | } | |
765 | ||
766 | return true; | |
767 | } | |
768 | ||
1660cb3a JM |
769 | /* Returns nonzero if FN is a declaration of a standard C library |
770 | function which is known not to throw. | |
771 | ||
772 | [lib.res.on.exception.handling]: None of the functions from the | |
773 | Standard C library shall report an error by throwing an | |
774 | exception, unless it calls a program-supplied function that | |
775 | throws an exception. */ | |
776 | ||
777 | #include "cfns.h" | |
778 | ||
779 | int | |
780 | nothrow_libfn_p (fn) | |
781 | tree fn; | |
782 | { | |
783 | tree id; | |
784 | ||
785 | if (TREE_PUBLIC (fn) | |
786 | && DECL_EXTERNAL (fn) | |
92643fea | 787 | && DECL_NAMESPACE_SCOPE_P (fn) |
eb68cb58 | 788 | && DECL_EXTERN_C_P (fn)) |
1660cb3a JM |
789 | /* OK */; |
790 | else | |
791 | /* Can't be a C library function. */ | |
792 | return 0; | |
793 | ||
794 | id = DECL_ASSEMBLER_NAME (fn); | |
795 | return !!libc_name_p (IDENTIFIER_POINTER (id), IDENTIFIER_LENGTH (id)); | |
796 | } | |
2bc9f1d1 JM |
797 | |
798 | /* Returns nonzero if an exception of type FROM will be caught by a | |
799 | handler for type TO, as per [except.handle]. */ | |
800 | ||
801 | static int | |
802 | can_convert_eh (to, from) | |
803 | tree to, from; | |
804 | { | |
805 | if (TREE_CODE (to) == REFERENCE_TYPE) | |
806 | to = TREE_TYPE (to); | |
807 | if (TREE_CODE (from) == REFERENCE_TYPE) | |
808 | from = TREE_TYPE (from); | |
809 | ||
810 | if (TREE_CODE (to) == POINTER_TYPE && TREE_CODE (from) == POINTER_TYPE) | |
811 | { | |
812 | to = TREE_TYPE (to); | |
813 | from = TREE_TYPE (from); | |
814 | ||
815 | if (! at_least_as_qualified_p (to, from)) | |
816 | return 0; | |
817 | ||
818 | if (TREE_CODE (to) == VOID_TYPE) | |
819 | return 1; | |
820 | ||
821 | /* else fall through */ | |
822 | } | |
823 | ||
2d46ec83 | 824 | if (CLASS_TYPE_P (to) && CLASS_TYPE_P (from) |
2bc9f1d1 JM |
825 | && PUBLICLY_UNIQUELY_DERIVED_P (to, from)) |
826 | return 1; | |
827 | ||
828 | return 0; | |
829 | } | |
830 | ||
831 | /* Check whether any of HANDLERS are shadowed by another handler accepting | |
832 | TYPE. Note that the shadowing may not be complete; even if an exception | |
833 | of type B would be caught by a handler for A, there could be a derived | |
834 | class C for which A is an ambiguous base but B is not, so the handler | |
835 | for B would catch an exception of type C. */ | |
836 | ||
837 | static void | |
838 | check_handlers_1 (master, handlers) | |
839 | tree master; | |
840 | tree handlers; | |
841 | { | |
842 | tree type = TREE_TYPE (master); | |
843 | tree handler; | |
844 | ||
845 | for (handler = handlers; handler; handler = TREE_CHAIN (handler)) | |
846 | if (TREE_TYPE (handler) | |
847 | && can_convert_eh (type, TREE_TYPE (handler))) | |
848 | { | |
849 | lineno = STMT_LINENO (handler); | |
850 | cp_warning ("exception of type `%T' will be caught", | |
851 | TREE_TYPE (handler)); | |
852 | lineno = STMT_LINENO (master); | |
853 | cp_warning (" by earlier handler for `%T'", type); | |
854 | break; | |
855 | } | |
856 | } | |
857 | ||
858 | /* Given a chain of HANDLERs, make sure that they're OK. */ | |
859 | ||
860 | void | |
861 | check_handlers (handlers) | |
862 | tree handlers; | |
863 | { | |
864 | tree handler; | |
865 | int save_line = lineno; | |
866 | for (handler = handlers; handler; handler = TREE_CHAIN (handler)) | |
867 | { | |
868 | if (TREE_CHAIN (handler) == NULL_TREE) | |
869 | /* No more handlers; nothing to shadow. */; | |
870 | else if (TREE_TYPE (handler) == NULL_TREE) | |
871 | { | |
872 | lineno = STMT_LINENO (handler); | |
873 | cp_pedwarn | |
874 | ("`...' handler must be the last handler for its try block"); | |
875 | } | |
876 | else | |
877 | check_handlers_1 (handler, TREE_CHAIN (handler)); | |
878 | } | |
879 | lineno = save_line; | |
880 | } |