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12670d88 | 1 | /* Implements exception handling. |
e5e809f4 | 2 | Copyright (C) 1989, 92-97, 1998 Free Software Foundation, Inc. |
4956d07c MS |
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 | ||
12670d88 RK |
23 | /* An exception is an event that can be signaled from within a |
24 | function. This event can then be "caught" or "trapped" by the | |
25 | callers of this function. This potentially allows program flow to | |
956d6950 | 26 | be transferred to any arbitrary code associated with a function call |
12670d88 RK |
27 | several levels up the stack. |
28 | ||
29 | The intended use for this mechanism is for signaling "exceptional | |
30 | events" in an out-of-band fashion, hence its name. The C++ language | |
31 | (and many other OO-styled or functional languages) practically | |
32 | requires such a mechanism, as otherwise it becomes very difficult | |
33 | or even impossible to signal failure conditions in complex | |
34 | situations. The traditional C++ example is when an error occurs in | |
35 | the process of constructing an object; without such a mechanism, it | |
36 | is impossible to signal that the error occurs without adding global | |
37 | state variables and error checks around every object construction. | |
38 | ||
39 | The act of causing this event to occur is referred to as "throwing | |
40 | an exception". (Alternate terms include "raising an exception" or | |
41 | "signaling an exception".) The term "throw" is used because control | |
42 | is returned to the callers of the function that is signaling the | |
43 | exception, and thus there is the concept of "throwing" the | |
44 | exception up the call stack. | |
45 | ||
27a36778 MS |
46 | There are two major codegen options for exception handling. The |
47 | flag -fsjlj-exceptions can be used to select the setjmp/longjmp | |
e9a25f70 | 48 | approach, which is the default. -fno-sjlj-exceptions can be used to |
27a36778 MS |
49 | get the PC range table approach. While this is a compile time |
50 | flag, an entire application must be compiled with the same codegen | |
51 | option. The first is a PC range table approach, the second is a | |
52 | setjmp/longjmp based scheme. We will first discuss the PC range | |
53 | table approach, after that, we will discuss the setjmp/longjmp | |
54 | based approach. | |
55 | ||
12670d88 RK |
56 | It is appropriate to speak of the "context of a throw". This |
57 | context refers to the address where the exception is thrown from, | |
58 | and is used to determine which exception region will handle the | |
59 | exception. | |
60 | ||
61 | Regions of code within a function can be marked such that if it | |
62 | contains the context of a throw, control will be passed to a | |
63 | designated "exception handler". These areas are known as "exception | |
64 | regions". Exception regions cannot overlap, but they can be nested | |
65 | to any arbitrary depth. Also, exception regions cannot cross | |
66 | function boundaries. | |
67 | ||
2ed18e63 MS |
68 | Exception handlers can either be specified by the user (which we |
69 | will call a "user-defined handler") or generated by the compiler | |
70 | (which we will designate as a "cleanup"). Cleanups are used to | |
71 | perform tasks such as destruction of objects allocated on the | |
72 | stack. | |
73 | ||
956d6950 | 74 | In the current implementation, cleanups are handled by allocating an |
2ed18e63 MS |
75 | exception region for the area that the cleanup is designated for, |
76 | and the handler for the region performs the cleanup and then | |
77 | rethrows the exception to the outer exception region. From the | |
78 | standpoint of the current implementation, there is little | |
79 | distinction made between a cleanup and a user-defined handler, and | |
80 | the phrase "exception handler" can be used to refer to either one | |
81 | equally well. (The section "Future Directions" below discusses how | |
82 | this will change). | |
83 | ||
84 | Each object file that is compiled with exception handling contains | |
85 | a static array of exception handlers named __EXCEPTION_TABLE__. | |
86 | Each entry contains the starting and ending addresses of the | |
87 | exception region, and the address of the handler designated for | |
88 | that region. | |
12670d88 | 89 | |
ca55abae JM |
90 | If the target does not use the DWARF 2 frame unwind information, at |
91 | program startup each object file invokes a function named | |
12670d88 | 92 | __register_exceptions with the address of its local |
ca55abae JM |
93 | __EXCEPTION_TABLE__. __register_exceptions is defined in libgcc2.c, and |
94 | is responsible for recording all of the exception regions into one list | |
95 | (which is kept in a static variable named exception_table_list). | |
96 | ||
97 | On targets that support crtstuff.c, the unwind information | |
98 | is stored in a section named .eh_frame and the information for the | |
99 | entire shared object or program is registered with a call to | |
6d8ccdbb | 100 | __register_frame_info. On other targets, the information for each |
d1485032 | 101 | translation unit is registered from the file generated by collect2. |
6d8ccdbb | 102 | __register_frame_info is defined in frame.c, and is responsible for |
ca55abae JM |
103 | recording all of the unwind regions into one list (which is kept in a |
104 | static variable named unwind_table_list). | |
12670d88 | 105 | |
27a36778 | 106 | The function __throw is actually responsible for doing the |
ca55abae JM |
107 | throw. On machines that have unwind info support, __throw is generated |
108 | by code in libgcc2.c, otherwise __throw is generated on a | |
12670d88 | 109 | per-object-file basis for each source file compiled with |
38e01259 | 110 | -fexceptions by the C++ frontend. Before __throw is invoked, |
ca55abae JM |
111 | the current context of the throw needs to be placed in the global |
112 | variable __eh_pc. | |
12670d88 | 113 | |
27a36778 | 114 | __throw attempts to find the appropriate exception handler for the |
12670d88 | 115 | PC value stored in __eh_pc by calling __find_first_exception_table_match |
2ed18e63 | 116 | (which is defined in libgcc2.c). If __find_first_exception_table_match |
ca55abae JM |
117 | finds a relevant handler, __throw transfers control directly to it. |
118 | ||
119 | If a handler for the context being thrown from can't be found, __throw | |
120 | walks (see Walking the stack below) the stack up the dynamic call chain to | |
121 | continue searching for an appropriate exception handler based upon the | |
122 | caller of the function it last sought a exception handler for. It stops | |
123 | then either an exception handler is found, or when the top of the | |
124 | call chain is reached. | |
125 | ||
126 | If no handler is found, an external library function named | |
127 | __terminate is called. If a handler is found, then we restart | |
128 | our search for a handler at the end of the call chain, and repeat | |
129 | the search process, but instead of just walking up the call chain, | |
130 | we unwind the call chain as we walk up it. | |
12670d88 RK |
131 | |
132 | Internal implementation details: | |
133 | ||
12670d88 | 134 | To associate a user-defined handler with a block of statements, the |
27a36778 | 135 | function expand_start_try_stmts is used to mark the start of the |
12670d88 | 136 | block of statements with which the handler is to be associated |
2ed18e63 MS |
137 | (which is known as a "try block"). All statements that appear |
138 | afterwards will be associated with the try block. | |
139 | ||
27a36778 | 140 | A call to expand_start_all_catch marks the end of the try block, |
2ed18e63 MS |
141 | and also marks the start of the "catch block" (the user-defined |
142 | handler) associated with the try block. | |
143 | ||
144 | This user-defined handler will be invoked for *every* exception | |
145 | thrown with the context of the try block. It is up to the handler | |
146 | to decide whether or not it wishes to handle any given exception, | |
147 | as there is currently no mechanism in this implementation for doing | |
148 | this. (There are plans for conditionally processing an exception | |
149 | based on its "type", which will provide a language-independent | |
150 | mechanism). | |
151 | ||
152 | If the handler chooses not to process the exception (perhaps by | |
153 | looking at an "exception type" or some other additional data | |
154 | supplied with the exception), it can fall through to the end of the | |
27a36778 | 155 | handler. expand_end_all_catch and expand_leftover_cleanups |
2ed18e63 MS |
156 | add additional code to the end of each handler to take care of |
157 | rethrowing to the outer exception handler. | |
158 | ||
159 | The handler also has the option to continue with "normal flow of | |
160 | code", or in other words to resume executing at the statement | |
161 | immediately after the end of the exception region. The variable | |
162 | caught_return_label_stack contains a stack of labels, and jumping | |
27a36778 | 163 | to the topmost entry's label via expand_goto will resume normal |
2ed18e63 MS |
164 | flow to the statement immediately after the end of the exception |
165 | region. If the handler falls through to the end, the exception will | |
166 | be rethrown to the outer exception region. | |
167 | ||
168 | The instructions for the catch block are kept as a separate | |
169 | sequence, and will be emitted at the end of the function along with | |
27a36778 MS |
170 | the handlers specified via expand_eh_region_end. The end of the |
171 | catch block is marked with expand_end_all_catch. | |
12670d88 RK |
172 | |
173 | Any data associated with the exception must currently be handled by | |
174 | some external mechanism maintained in the frontend. For example, | |
175 | the C++ exception mechanism passes an arbitrary value along with | |
176 | the exception, and this is handled in the C++ frontend by using a | |
2ed18e63 MS |
177 | global variable to hold the value. (This will be changing in the |
178 | future.) | |
179 | ||
180 | The mechanism in C++ for handling data associated with the | |
181 | exception is clearly not thread-safe. For a thread-based | |
182 | environment, another mechanism must be used (possibly using a | |
183 | per-thread allocation mechanism if the size of the area that needs | |
184 | to be allocated isn't known at compile time.) | |
185 | ||
186 | Internally-generated exception regions (cleanups) are marked by | |
27a36778 | 187 | calling expand_eh_region_start to mark the start of the region, |
2ed18e63 MS |
188 | and expand_eh_region_end (handler) is used to both designate the |
189 | end of the region and to associate a specified handler/cleanup with | |
190 | the region. The rtl code in HANDLER will be invoked whenever an | |
191 | exception occurs in the region between the calls to | |
192 | expand_eh_region_start and expand_eh_region_end. After HANDLER is | |
193 | executed, additional code is emitted to handle rethrowing the | |
194 | exception to the outer exception handler. The code for HANDLER will | |
195 | be emitted at the end of the function. | |
12670d88 RK |
196 | |
197 | TARGET_EXPRs can also be used to designate exception regions. A | |
198 | TARGET_EXPR gives an unwind-protect style interface commonly used | |
199 | in functional languages such as LISP. The associated expression is | |
2ed18e63 MS |
200 | evaluated, and whether or not it (or any of the functions that it |
201 | calls) throws an exception, the protect expression is always | |
202 | invoked. This implementation takes care of the details of | |
203 | associating an exception table entry with the expression and | |
204 | generating the necessary code (it actually emits the protect | |
205 | expression twice, once for normal flow and once for the exception | |
206 | case). As for the other handlers, the code for the exception case | |
207 | will be emitted at the end of the function. | |
208 | ||
209 | Cleanups can also be specified by using add_partial_entry (handler) | |
27a36778 | 210 | and end_protect_partials. add_partial_entry creates the start of |
2ed18e63 MS |
211 | a new exception region; HANDLER will be invoked if an exception is |
212 | thrown with the context of the region between the calls to | |
213 | add_partial_entry and end_protect_partials. end_protect_partials is | |
214 | used to mark the end of these regions. add_partial_entry can be | |
215 | called as many times as needed before calling end_protect_partials. | |
216 | However, end_protect_partials should only be invoked once for each | |
27a36778 | 217 | group of calls to add_partial_entry as the entries are queued |
2ed18e63 MS |
218 | and all of the outstanding entries are processed simultaneously |
219 | when end_protect_partials is invoked. Similarly to the other | |
220 | handlers, the code for HANDLER will be emitted at the end of the | |
221 | function. | |
12670d88 RK |
222 | |
223 | The generated RTL for an exception region includes | |
224 | NOTE_INSN_EH_REGION_BEG and NOTE_INSN_EH_REGION_END notes that mark | |
225 | the start and end of the exception region. A unique label is also | |
2ed18e63 MS |
226 | generated at the start of the exception region, which is available |
227 | by looking at the ehstack variable. The topmost entry corresponds | |
228 | to the current region. | |
12670d88 RK |
229 | |
230 | In the current implementation, an exception can only be thrown from | |
231 | a function call (since the mechanism used to actually throw an | |
232 | exception involves calling __throw). If an exception region is | |
233 | created but no function calls occur within that region, the region | |
2ed18e63 | 234 | can be safely optimized away (along with its exception handlers) |
27a36778 MS |
235 | since no exceptions can ever be caught in that region. This |
236 | optimization is performed unless -fasynchronous-exceptions is | |
237 | given. If the user wishes to throw from a signal handler, or other | |
238 | asynchronous place, -fasynchronous-exceptions should be used when | |
239 | compiling for maximally correct code, at the cost of additional | |
240 | exception regions. Using -fasynchronous-exceptions only produces | |
241 | code that is reasonably safe in such situations, but a correct | |
242 | program cannot rely upon this working. It can be used in failsafe | |
243 | code, where trying to continue on, and proceeding with potentially | |
244 | incorrect results is better than halting the program. | |
245 | ||
12670d88 | 246 | |
ca55abae | 247 | Walking the stack: |
12670d88 | 248 | |
ca55abae JM |
249 | The stack is walked by starting with a pointer to the current |
250 | frame, and finding the pointer to the callers frame. The unwind info | |
251 | tells __throw how to find it. | |
12670d88 | 252 | |
ca55abae | 253 | Unwinding the stack: |
12670d88 | 254 | |
ca55abae JM |
255 | When we use the term unwinding the stack, we mean undoing the |
256 | effects of the function prologue in a controlled fashion so that we | |
257 | still have the flow of control. Otherwise, we could just return | |
258 | (jump to the normal end of function epilogue). | |
259 | ||
260 | This is done in __throw in libgcc2.c when we know that a handler exists | |
261 | in a frame higher up the call stack than its immediate caller. | |
262 | ||
263 | To unwind, we find the unwind data associated with the frame, if any. | |
264 | If we don't find any, we call the library routine __terminate. If we do | |
265 | find it, we use the information to copy the saved register values from | |
266 | that frame into the register save area in the frame for __throw, return | |
267 | into a stub which updates the stack pointer, and jump to the handler. | |
268 | The normal function epilogue for __throw handles restoring the saved | |
269 | values into registers. | |
270 | ||
271 | When unwinding, we use this method if we know it will | |
272 | work (if DWARF2_UNWIND_INFO is defined). Otherwise, we know that | |
273 | an inline unwinder will have been emitted for any function that | |
274 | __unwind_function cannot unwind. The inline unwinder appears as a | |
275 | normal exception handler for the entire function, for any function | |
276 | that we know cannot be unwound by __unwind_function. We inform the | |
277 | compiler of whether a function can be unwound with | |
278 | __unwind_function by having DOESNT_NEED_UNWINDER evaluate to true | |
279 | when the unwinder isn't needed. __unwind_function is used as an | |
280 | action of last resort. If no other method can be used for | |
281 | unwinding, __unwind_function is used. If it cannot unwind, it | |
956d6950 | 282 | should call __terminate. |
ca55abae JM |
283 | |
284 | By default, if the target-specific backend doesn't supply a definition | |
285 | for __unwind_function and doesn't support DWARF2_UNWIND_INFO, inlined | |
286 | unwinders will be used instead. The main tradeoff here is in text space | |
287 | utilization. Obviously, if inline unwinders have to be generated | |
288 | repeatedly, this uses much more space than if a single routine is used. | |
2ed18e63 MS |
289 | |
290 | However, it is simply not possible on some platforms to write a | |
291 | generalized routine for doing stack unwinding without having some | |
ca55abae JM |
292 | form of additional data associated with each function. The current |
293 | implementation can encode this data in the form of additional | |
294 | machine instructions or as static data in tabular form. The later | |
295 | is called the unwind data. | |
12670d88 | 296 | |
ca55abae JM |
297 | The backend macro DOESNT_NEED_UNWINDER is used to conditionalize whether |
298 | or not per-function unwinders are needed. If DOESNT_NEED_UNWINDER is | |
299 | defined and has a non-zero value, a per-function unwinder is not emitted | |
300 | for the current function. If the static unwind data is supported, then | |
301 | a per-function unwinder is not emitted. | |
12670d88 | 302 | |
27a36778 | 303 | On some platforms it is possible that neither __unwind_function |
12670d88 | 304 | nor inlined unwinders are available. For these platforms it is not |
27a36778 | 305 | possible to throw through a function call, and abort will be |
2ed18e63 MS |
306 | invoked instead of performing the throw. |
307 | ||
ca55abae JM |
308 | The reason the unwind data may be needed is that on some platforms |
309 | the order and types of data stored on the stack can vary depending | |
310 | on the type of function, its arguments and returned values, and the | |
311 | compilation options used (optimization versus non-optimization, | |
312 | -fomit-frame-pointer, processor variations, etc). | |
313 | ||
314 | Unfortunately, this also means that throwing through functions that | |
315 | aren't compiled with exception handling support will still not be | |
316 | possible on some platforms. This problem is currently being | |
317 | investigated, but no solutions have been found that do not imply | |
318 | some unacceptable performance penalties. | |
319 | ||
2ed18e63 MS |
320 | Future directions: |
321 | ||
27a36778 | 322 | Currently __throw makes no differentiation between cleanups and |
2ed18e63 MS |
323 | user-defined exception regions. While this makes the implementation |
324 | simple, it also implies that it is impossible to determine if a | |
325 | user-defined exception handler exists for a given exception without | |
326 | completely unwinding the stack in the process. This is undesirable | |
327 | from the standpoint of debugging, as ideally it would be possible | |
328 | to trap unhandled exceptions in the debugger before the process of | |
329 | unwinding has even started. | |
330 | ||
331 | This problem can be solved by marking user-defined handlers in a | |
332 | special way (probably by adding additional bits to exception_table_list). | |
27a36778 | 333 | A two-pass scheme could then be used by __throw to iterate |
2ed18e63 MS |
334 | through the table. The first pass would search for a relevant |
335 | user-defined handler for the current context of the throw, and if | |
336 | one is found, the second pass would then invoke all needed cleanups | |
337 | before jumping to the user-defined handler. | |
338 | ||
339 | Many languages (including C++ and Ada) make execution of a | |
340 | user-defined handler conditional on the "type" of the exception | |
341 | thrown. (The type of the exception is actually the type of the data | |
342 | that is thrown with the exception.) It will thus be necessary for | |
27a36778 | 343 | __throw to be able to determine if a given user-defined |
2ed18e63 MS |
344 | exception handler will actually be executed, given the type of |
345 | exception. | |
346 | ||
347 | One scheme is to add additional information to exception_table_list | |
27a36778 | 348 | as to the types of exceptions accepted by each handler. __throw |
2ed18e63 MS |
349 | can do the type comparisons and then determine if the handler is |
350 | actually going to be executed. | |
351 | ||
352 | There is currently no significant level of debugging support | |
27a36778 | 353 | available, other than to place a breakpoint on __throw. While |
2ed18e63 MS |
354 | this is sufficient in most cases, it would be helpful to be able to |
355 | know where a given exception was going to be thrown to before it is | |
356 | actually thrown, and to be able to choose between stopping before | |
357 | every exception region (including cleanups), or just user-defined | |
358 | exception regions. This should be possible to do in the two-pass | |
27a36778 | 359 | scheme by adding additional labels to __throw for appropriate |
2ed18e63 MS |
360 | breakpoints, and additional debugger commands could be added to |
361 | query various state variables to determine what actions are to be | |
362 | performed next. | |
363 | ||
ca55abae JM |
364 | Another major problem that is being worked on is the issue with stack |
365 | unwinding on various platforms. Currently the only platforms that have | |
366 | support for the generation of a generic unwinder are the SPARC and MIPS. | |
367 | All other ports require per-function unwinders, which produce large | |
368 | amounts of code bloat. | |
27a36778 MS |
369 | |
370 | For setjmp/longjmp based exception handling, some of the details | |
371 | are as above, but there are some additional details. This section | |
372 | discusses the details. | |
373 | ||
374 | We don't use NOTE_INSN_EH_REGION_{BEG,END} pairs. We don't | |
375 | optimize EH regions yet. We don't have to worry about machine | |
376 | specific issues with unwinding the stack, as we rely upon longjmp | |
377 | for all the machine specific details. There is no variable context | |
378 | of a throw, just the one implied by the dynamic handler stack | |
379 | pointed to by the dynamic handler chain. There is no exception | |
956d6950 | 380 | table, and no calls to __register_exceptions. __sjthrow is used |
27a36778 MS |
381 | instead of __throw, and it works by using the dynamic handler |
382 | chain, and longjmp. -fasynchronous-exceptions has no effect, as | |
383 | the elimination of trivial exception regions is not yet performed. | |
384 | ||
385 | A frontend can set protect_cleanup_actions_with_terminate when all | |
386 | the cleanup actions should be protected with an EH region that | |
387 | calls terminate when an unhandled exception is throw. C++ does | |
388 | this, Ada does not. */ | |
4956d07c MS |
389 | |
390 | ||
391 | #include "config.h" | |
ca55abae | 392 | #include "defaults.h" |
9a0d1e1b | 393 | #include "eh-common.h" |
670ee920 | 394 | #include "system.h" |
4956d07c MS |
395 | #include "rtl.h" |
396 | #include "tree.h" | |
397 | #include "flags.h" | |
398 | #include "except.h" | |
399 | #include "function.h" | |
400 | #include "insn-flags.h" | |
401 | #include "expr.h" | |
402 | #include "insn-codes.h" | |
403 | #include "regs.h" | |
404 | #include "hard-reg-set.h" | |
405 | #include "insn-config.h" | |
406 | #include "recog.h" | |
407 | #include "output.h" | |
10f0ad3d | 408 | #include "toplev.h" |
e6cfb550 | 409 | #include "obstack.h" |
4956d07c | 410 | |
27a36778 MS |
411 | /* One to use setjmp/longjmp method of generating code for exception |
412 | handling. */ | |
413 | ||
d1485032 | 414 | int exceptions_via_longjmp = 2; |
27a36778 MS |
415 | |
416 | /* One to enable asynchronous exception support. */ | |
417 | ||
418 | int asynchronous_exceptions = 0; | |
419 | ||
420 | /* One to protect cleanup actions with a handler that calls | |
421 | __terminate, zero otherwise. */ | |
422 | ||
e701eb4d | 423 | int protect_cleanup_actions_with_terminate; |
27a36778 | 424 | |
12670d88 | 425 | /* A list of labels used for exception handlers. Created by |
4956d07c MS |
426 | find_exception_handler_labels for the optimization passes. */ |
427 | ||
428 | rtx exception_handler_labels; | |
429 | ||
154bba13 TT |
430 | /* The EH context. Nonzero if the function has already |
431 | fetched a pointer to the EH context for exception handling. */ | |
27a36778 | 432 | |
154bba13 | 433 | rtx current_function_ehc; |
27a36778 | 434 | |
956d6950 | 435 | /* A stack used for keeping track of the currently active exception |
12670d88 | 436 | handling region. As each exception region is started, an entry |
4956d07c MS |
437 | describing the region is pushed onto this stack. The current |
438 | region can be found by looking at the top of the stack, and as we | |
12670d88 RK |
439 | exit regions, the corresponding entries are popped. |
440 | ||
27a36778 | 441 | Entries cannot overlap; they can be nested. So there is only one |
12670d88 RK |
442 | entry at most that corresponds to the current instruction, and that |
443 | is the entry on the top of the stack. */ | |
4956d07c | 444 | |
27a36778 | 445 | static struct eh_stack ehstack; |
4956d07c | 446 | |
9a0d1e1b AM |
447 | |
448 | /* This stack is used to represent what the current eh region is | |
449 | for the catch blocks beings processed */ | |
450 | ||
451 | static struct eh_stack catchstack; | |
452 | ||
12670d88 RK |
453 | /* A queue used for tracking which exception regions have closed but |
454 | whose handlers have not yet been expanded. Regions are emitted in | |
455 | groups in an attempt to improve paging performance. | |
456 | ||
457 | As we exit a region, we enqueue a new entry. The entries are then | |
27a36778 | 458 | dequeued during expand_leftover_cleanups and expand_start_all_catch, |
12670d88 RK |
459 | |
460 | We should redo things so that we either take RTL for the handler, | |
461 | or we expand the handler expressed as a tree immediately at region | |
462 | end time. */ | |
4956d07c | 463 | |
27a36778 | 464 | static struct eh_queue ehqueue; |
4956d07c | 465 | |
12670d88 | 466 | /* Insns for all of the exception handlers for the current function. |
abeeec2a | 467 | They are currently emitted by the frontend code. */ |
4956d07c MS |
468 | |
469 | rtx catch_clauses; | |
470 | ||
12670d88 RK |
471 | /* A TREE_CHAINed list of handlers for regions that are not yet |
472 | closed. The TREE_VALUE of each entry contains the handler for the | |
abeeec2a | 473 | corresponding entry on the ehstack. */ |
4956d07c | 474 | |
12670d88 | 475 | static tree protect_list; |
4956d07c MS |
476 | |
477 | /* Stacks to keep track of various labels. */ | |
478 | ||
12670d88 RK |
479 | /* Keeps track of the label to resume to should one want to resume |
480 | normal control flow out of a handler (instead of, say, returning to | |
1418bb67 | 481 | the caller of the current function or exiting the program). */ |
4956d07c MS |
482 | |
483 | struct label_node *caught_return_label_stack = NULL; | |
484 | ||
956d6950 JL |
485 | /* Keeps track of the label used as the context of a throw to rethrow an |
486 | exception to the outer exception region. */ | |
487 | ||
488 | struct label_node *outer_context_label_stack = NULL; | |
489 | ||
12670d88 | 490 | /* A random data area for the front end's own use. */ |
4956d07c MS |
491 | |
492 | struct label_node *false_label_stack = NULL; | |
493 | ||
71038426 RH |
494 | /* Pseudos used to hold exception return data in the interim between |
495 | __builtin_eh_return and the end of the function. */ | |
496 | ||
497 | static rtx eh_return_context; | |
498 | static rtx eh_return_stack_adjust; | |
499 | static rtx eh_return_handler; | |
500 | ||
501 | /* Used to mark the eh return stub for flow, so that the Right Thing | |
502 | happens with the values for the hardregs therin. */ | |
503 | ||
504 | rtx eh_return_stub_label; | |
505 | ||
e6cfb550 AM |
506 | /* This is used for targets which can call rethrow with an offset instead |
507 | of an address. This is subtracted from the rethrow label we are | |
508 | interested in. */ | |
509 | ||
510 | static rtx first_rethrow_symbol = NULL_RTX; | |
511 | static rtx final_rethrow = NULL_RTX; | |
512 | static rtx last_rethrow_symbol = NULL_RTX; | |
513 | ||
514 | ||
71038426 RH |
515 | /* Prototypes for local functions. */ |
516 | ||
242c13b0 JL |
517 | static void push_eh_entry PROTO((struct eh_stack *)); |
518 | static struct eh_entry * pop_eh_entry PROTO((struct eh_stack *)); | |
519 | static void enqueue_eh_entry PROTO((struct eh_queue *, struct eh_entry *)); | |
520 | static struct eh_entry * dequeue_eh_entry PROTO((struct eh_queue *)); | |
521 | static rtx call_get_eh_context PROTO((void)); | |
522 | static void start_dynamic_cleanup PROTO((tree, tree)); | |
523 | static void start_dynamic_handler PROTO((void)); | |
e701eb4d | 524 | static void expand_rethrow PROTO((rtx)); |
242c13b0 JL |
525 | static void output_exception_table_entry PROTO((FILE *, int)); |
526 | static int can_throw PROTO((rtx)); | |
527 | static rtx scan_region PROTO((rtx, int, int *)); | |
71038426 | 528 | static void eh_regs PROTO((rtx *, rtx *, rtx *, int)); |
242c13b0 | 529 | static void set_insn_eh_region PROTO((rtx *, int)); |
767f5b14 | 530 | #ifdef DONT_USE_BUILTIN_SETJMP |
561592c5 | 531 | static void jumpif_rtx PROTO((rtx, rtx)); |
767f5b14 | 532 | #endif |
561592c5 | 533 | |
242c13b0 | 534 | rtx expand_builtin_return_addr PROTO((enum built_in_function, int, rtx)); |
4956d07c MS |
535 | \f |
536 | /* Various support routines to manipulate the various data structures | |
537 | used by the exception handling code. */ | |
538 | ||
e6cfb550 AM |
539 | extern struct obstack permanent_obstack; |
540 | ||
541 | /* Generate a SYMBOL_REF for rethrow to use */ | |
542 | static rtx | |
543 | create_rethrow_ref (region_num) | |
544 | int region_num; | |
545 | { | |
546 | rtx def; | |
547 | char *ptr; | |
548 | char buf[60]; | |
549 | ||
550 | push_obstacks_nochange (); | |
551 | end_temporary_allocation (); | |
552 | ||
553 | ASM_GENERATE_INTERNAL_LABEL (buf, "LRTH", region_num); | |
554 | ptr = (char *) obstack_copy0 (&permanent_obstack, buf, strlen (buf)); | |
555 | def = gen_rtx_SYMBOL_REF (Pmode, ptr); | |
556 | SYMBOL_REF_NEED_ADJUST (def) = 1; | |
557 | ||
558 | pop_obstacks (); | |
559 | return def; | |
560 | } | |
561 | ||
4956d07c MS |
562 | /* Push a label entry onto the given STACK. */ |
563 | ||
564 | void | |
565 | push_label_entry (stack, rlabel, tlabel) | |
566 | struct label_node **stack; | |
567 | rtx rlabel; | |
568 | tree tlabel; | |
569 | { | |
570 | struct label_node *newnode | |
571 | = (struct label_node *) xmalloc (sizeof (struct label_node)); | |
572 | ||
573 | if (rlabel) | |
574 | newnode->u.rlabel = rlabel; | |
575 | else | |
576 | newnode->u.tlabel = tlabel; | |
577 | newnode->chain = *stack; | |
578 | *stack = newnode; | |
579 | } | |
580 | ||
581 | /* Pop a label entry from the given STACK. */ | |
582 | ||
583 | rtx | |
584 | pop_label_entry (stack) | |
585 | struct label_node **stack; | |
586 | { | |
587 | rtx label; | |
588 | struct label_node *tempnode; | |
589 | ||
590 | if (! *stack) | |
591 | return NULL_RTX; | |
592 | ||
593 | tempnode = *stack; | |
594 | label = tempnode->u.rlabel; | |
595 | *stack = (*stack)->chain; | |
596 | free (tempnode); | |
597 | ||
598 | return label; | |
599 | } | |
600 | ||
601 | /* Return the top element of the given STACK. */ | |
602 | ||
603 | tree | |
604 | top_label_entry (stack) | |
605 | struct label_node **stack; | |
606 | { | |
607 | if (! *stack) | |
608 | return NULL_TREE; | |
609 | ||
610 | return (*stack)->u.tlabel; | |
611 | } | |
612 | ||
9a0d1e1b AM |
613 | /* get an exception label. These must be on the permanent obstack */ |
614 | ||
615 | rtx | |
616 | gen_exception_label () | |
617 | { | |
618 | rtx lab; | |
9a0d1e1b | 619 | lab = gen_label_rtx (); |
9a0d1e1b AM |
620 | return lab; |
621 | } | |
622 | ||
478b0752 | 623 | /* Push a new eh_node entry onto STACK. */ |
4956d07c | 624 | |
478b0752 | 625 | static void |
4956d07c MS |
626 | push_eh_entry (stack) |
627 | struct eh_stack *stack; | |
628 | { | |
629 | struct eh_node *node = (struct eh_node *) xmalloc (sizeof (struct eh_node)); | |
630 | struct eh_entry *entry = (struct eh_entry *) xmalloc (sizeof (struct eh_entry)); | |
631 | ||
e6cfb550 | 632 | rtx rlab = gen_exception_label (); |
4956d07c | 633 | entry->finalization = NULL_TREE; |
9a0d1e1b | 634 | entry->label_used = 0; |
e6cfb550 | 635 | entry->exception_handler_label = rlab; |
bf71cd2e | 636 | entry->false_label = NULL_RTX; |
e6cfb550 AM |
637 | if (! flag_new_exceptions) |
638 | entry->outer_context = gen_label_rtx (); | |
639 | else | |
640 | entry->outer_context = create_rethrow_ref (CODE_LABEL_NUMBER (rlab)); | |
641 | entry->rethrow_label = entry->outer_context; | |
9a0d1e1b AM |
642 | |
643 | node->entry = entry; | |
644 | node->chain = stack->top; | |
645 | stack->top = node; | |
646 | } | |
4956d07c | 647 | |
9a0d1e1b AM |
648 | /* push an existing entry onto a stack. */ |
649 | static void | |
650 | push_entry (stack, entry) | |
651 | struct eh_stack *stack; | |
652 | struct eh_entry *entry; | |
653 | { | |
654 | struct eh_node *node = (struct eh_node *) xmalloc (sizeof (struct eh_node)); | |
4956d07c MS |
655 | node->entry = entry; |
656 | node->chain = stack->top; | |
657 | stack->top = node; | |
4956d07c MS |
658 | } |
659 | ||
660 | /* Pop an entry from the given STACK. */ | |
661 | ||
662 | static struct eh_entry * | |
663 | pop_eh_entry (stack) | |
664 | struct eh_stack *stack; | |
665 | { | |
666 | struct eh_node *tempnode; | |
667 | struct eh_entry *tempentry; | |
668 | ||
669 | tempnode = stack->top; | |
670 | tempentry = tempnode->entry; | |
671 | stack->top = stack->top->chain; | |
672 | free (tempnode); | |
673 | ||
674 | return tempentry; | |
675 | } | |
676 | ||
677 | /* Enqueue an ENTRY onto the given QUEUE. */ | |
678 | ||
679 | static void | |
680 | enqueue_eh_entry (queue, entry) | |
681 | struct eh_queue *queue; | |
682 | struct eh_entry *entry; | |
683 | { | |
684 | struct eh_node *node = (struct eh_node *) xmalloc (sizeof (struct eh_node)); | |
685 | ||
686 | node->entry = entry; | |
687 | node->chain = NULL; | |
688 | ||
689 | if (queue->head == NULL) | |
690 | { | |
691 | queue->head = node; | |
692 | } | |
693 | else | |
694 | { | |
695 | queue->tail->chain = node; | |
696 | } | |
697 | queue->tail = node; | |
698 | } | |
699 | ||
700 | /* Dequeue an entry from the given QUEUE. */ | |
701 | ||
702 | static struct eh_entry * | |
703 | dequeue_eh_entry (queue) | |
704 | struct eh_queue *queue; | |
705 | { | |
706 | struct eh_node *tempnode; | |
707 | struct eh_entry *tempentry; | |
708 | ||
709 | if (queue->head == NULL) | |
710 | return NULL; | |
711 | ||
712 | tempnode = queue->head; | |
713 | queue->head = queue->head->chain; | |
714 | ||
715 | tempentry = tempnode->entry; | |
716 | free (tempnode); | |
717 | ||
718 | return tempentry; | |
719 | } | |
9a0d1e1b AM |
720 | |
721 | static void | |
722 | receive_exception_label (handler_label) | |
723 | rtx handler_label; | |
724 | { | |
725 | emit_label (handler_label); | |
726 | ||
727 | #ifdef HAVE_exception_receiver | |
728 | if (! exceptions_via_longjmp) | |
729 | if (HAVE_exception_receiver) | |
730 | emit_insn (gen_exception_receiver ()); | |
731 | #endif | |
732 | ||
733 | #ifdef HAVE_nonlocal_goto_receiver | |
734 | if (! exceptions_via_longjmp) | |
735 | if (HAVE_nonlocal_goto_receiver) | |
736 | emit_insn (gen_nonlocal_goto_receiver ()); | |
737 | #endif | |
738 | } | |
739 | ||
740 | ||
741 | struct func_eh_entry | |
742 | { | |
743 | int range_number; /* EH region number from EH NOTE insn's */ | |
e6cfb550 | 744 | rtx rethrow_label; /* Label for rethrow */ |
9a0d1e1b AM |
745 | struct handler_info *handlers; |
746 | }; | |
747 | ||
748 | ||
749 | /* table of function eh regions */ | |
750 | static struct func_eh_entry *function_eh_regions = NULL; | |
751 | static int num_func_eh_entries = 0; | |
752 | static int current_func_eh_entry = 0; | |
753 | ||
754 | #define SIZE_FUNC_EH(X) (sizeof (struct func_eh_entry) * X) | |
755 | ||
756 | /* Add a new eh_entry for this function, and base it off of the information | |
e6cfb550 AM |
757 | in the EH_ENTRY parameter. A NULL parameter is invalid. |
758 | OUTER_CONTEXT is a label which is used for rethrowing. The number | |
9a0d1e1b AM |
759 | returned is an number which uniquely identifies this exception range. */ |
760 | ||
e6cfb550 AM |
761 | static int |
762 | new_eh_region_entry (note_eh_region, rethrow) | |
9a0d1e1b | 763 | int note_eh_region; |
e6cfb550 | 764 | rtx rethrow; |
9a0d1e1b AM |
765 | { |
766 | if (current_func_eh_entry == num_func_eh_entries) | |
767 | { | |
768 | if (num_func_eh_entries == 0) | |
769 | { | |
770 | function_eh_regions = | |
771 | (struct func_eh_entry *) malloc (SIZE_FUNC_EH (50)); | |
772 | num_func_eh_entries = 50; | |
773 | } | |
774 | else | |
775 | { | |
776 | num_func_eh_entries = num_func_eh_entries * 3 / 2; | |
777 | function_eh_regions = (struct func_eh_entry *) | |
778 | realloc (function_eh_regions, SIZE_FUNC_EH (num_func_eh_entries)); | |
779 | } | |
780 | } | |
781 | function_eh_regions[current_func_eh_entry].range_number = note_eh_region; | |
e6cfb550 AM |
782 | if (rethrow == NULL_RTX) |
783 | function_eh_regions[current_func_eh_entry].rethrow_label = | |
784 | create_rethrow_ref (note_eh_region); | |
785 | else | |
786 | function_eh_regions[current_func_eh_entry].rethrow_label = rethrow; | |
9a0d1e1b AM |
787 | function_eh_regions[current_func_eh_entry].handlers = NULL; |
788 | ||
789 | return current_func_eh_entry++; | |
790 | } | |
791 | ||
792 | /* Add new handler information to an exception range. The first parameter | |
793 | specifies the range number (returned from new_eh_entry()). The second | |
794 | parameter specifies the handler. By default the handler is inserted at | |
795 | the end of the list. A handler list may contain only ONE NULL_TREE | |
796 | typeinfo entry. Regardless where it is positioned, a NULL_TREE entry | |
797 | is always output as the LAST handler in the exception table for a region. */ | |
798 | ||
799 | void | |
800 | add_new_handler (region, newhandler) | |
801 | int region; | |
802 | struct handler_info *newhandler; | |
803 | { | |
804 | struct handler_info *last; | |
805 | ||
806 | newhandler->next = NULL; | |
807 | last = function_eh_regions[region].handlers; | |
808 | if (last == NULL) | |
809 | function_eh_regions[region].handlers = newhandler; | |
810 | else | |
811 | { | |
9bbdf48e JM |
812 | for ( ; ; last = last->next) |
813 | { | |
814 | if (last->type_info == CATCH_ALL_TYPE) | |
815 | pedwarn ("additional handler after ..."); | |
816 | if (last->next == NULL) | |
817 | break; | |
818 | } | |
d7e78529 | 819 | last->next = newhandler; |
9a0d1e1b AM |
820 | } |
821 | } | |
822 | ||
9f8e6243 AM |
823 | /* Remove a handler label. The handler label is being deleted, so all |
824 | regions which reference this handler should have it removed from their | |
825 | list of possible handlers. Any region which has the final handler | |
826 | removed can be deleted. */ | |
827 | ||
828 | void remove_handler (removing_label) | |
829 | rtx removing_label; | |
830 | { | |
831 | struct handler_info *handler, *last; | |
832 | int x; | |
833 | for (x = 0 ; x < current_func_eh_entry; ++x) | |
834 | { | |
835 | last = NULL; | |
836 | handler = function_eh_regions[x].handlers; | |
837 | for ( ; handler; last = handler, handler = handler->next) | |
838 | if (handler->handler_label == removing_label) | |
839 | { | |
840 | if (last) | |
841 | { | |
842 | last->next = handler->next; | |
843 | handler = last; | |
844 | } | |
845 | else | |
846 | function_eh_regions[x].handlers = handler->next; | |
847 | } | |
848 | } | |
849 | } | |
850 | ||
9c606f69 AM |
851 | /* This function will return a malloc'd pointer to an array of |
852 | void pointer representing the runtime match values that | |
853 | currently exist in all regions. */ | |
854 | ||
855 | int | |
4f70758f KG |
856 | find_all_handler_type_matches (array) |
857 | void ***array; | |
9c606f69 AM |
858 | { |
859 | struct handler_info *handler, *last; | |
860 | int x,y; | |
861 | void *val; | |
862 | void **ptr; | |
863 | int max_ptr; | |
864 | int n_ptr = 0; | |
865 | ||
866 | *array = NULL; | |
867 | ||
868 | if (!doing_eh (0) || ! flag_new_exceptions) | |
869 | return 0; | |
870 | ||
871 | max_ptr = 100; | |
872 | ptr = (void **)malloc (max_ptr * sizeof (void *)); | |
873 | ||
874 | if (ptr == NULL) | |
875 | return 0; | |
876 | ||
877 | for (x = 0 ; x < current_func_eh_entry; x++) | |
878 | { | |
879 | last = NULL; | |
880 | handler = function_eh_regions[x].handlers; | |
881 | for ( ; handler; last = handler, handler = handler->next) | |
882 | { | |
883 | val = handler->type_info; | |
884 | if (val != NULL && val != CATCH_ALL_TYPE) | |
885 | { | |
886 | /* See if this match value has already been found. */ | |
887 | for (y = 0; y < n_ptr; y++) | |
888 | if (ptr[y] == val) | |
889 | break; | |
890 | ||
891 | /* If we break early, we already found this value. */ | |
892 | if (y < n_ptr) | |
893 | continue; | |
894 | ||
895 | /* Do we need to allocate more space? */ | |
896 | if (n_ptr >= max_ptr) | |
897 | { | |
898 | max_ptr += max_ptr / 2; | |
899 | ptr = (void **)realloc (ptr, max_ptr * sizeof (void *)); | |
900 | if (ptr == NULL) | |
901 | return 0; | |
902 | } | |
903 | ptr[n_ptr] = val; | |
904 | n_ptr++; | |
905 | } | |
906 | } | |
907 | } | |
908 | *array = ptr; | |
909 | return n_ptr; | |
910 | } | |
911 | ||
9a0d1e1b AM |
912 | /* Create a new handler structure initialized with the handler label and |
913 | typeinfo fields passed in. */ | |
914 | ||
915 | struct handler_info * | |
916 | get_new_handler (handler, typeinfo) | |
917 | rtx handler; | |
918 | void *typeinfo; | |
919 | { | |
920 | struct handler_info* ptr; | |
921 | ptr = (struct handler_info *) malloc (sizeof (struct handler_info)); | |
922 | ptr->handler_label = handler; | |
0177de87 | 923 | ptr->handler_number = CODE_LABEL_NUMBER (handler); |
9a0d1e1b AM |
924 | ptr->type_info = typeinfo; |
925 | ptr->next = NULL; | |
926 | ||
927 | return ptr; | |
928 | } | |
929 | ||
930 | ||
931 | ||
932 | /* Find the index in function_eh_regions associated with a NOTE region. If | |
933 | the region cannot be found, a -1 is returned. This should never happen! */ | |
934 | ||
935 | int | |
936 | find_func_region (insn_region) | |
937 | int insn_region; | |
938 | { | |
939 | int x; | |
940 | for (x = 0; x < current_func_eh_entry; x++) | |
941 | if (function_eh_regions[x].range_number == insn_region) | |
942 | return x; | |
943 | ||
944 | return -1; | |
945 | } | |
946 | ||
947 | /* Get a pointer to the first handler in an exception region's list. */ | |
948 | ||
949 | struct handler_info * | |
950 | get_first_handler (region) | |
951 | int region; | |
952 | { | |
953 | return function_eh_regions[find_func_region (region)].handlers; | |
954 | } | |
955 | ||
956 | /* Clean out the function_eh_region table and free all memory */ | |
957 | ||
958 | static void | |
959 | clear_function_eh_region () | |
960 | { | |
961 | int x; | |
962 | struct handler_info *ptr, *next; | |
963 | for (x = 0; x < current_func_eh_entry; x++) | |
964 | for (ptr = function_eh_regions[x].handlers; ptr != NULL; ptr = next) | |
965 | { | |
966 | next = ptr->next; | |
967 | free (ptr); | |
968 | } | |
969 | free (function_eh_regions); | |
970 | num_func_eh_entries = 0; | |
971 | current_func_eh_entry = 0; | |
972 | } | |
973 | ||
974 | /* Make a duplicate of an exception region by copying all the handlers | |
e6cfb550 AM |
975 | for an exception region. Return the new handler index. The final |
976 | parameter is a routine which maps old labels to new ones. */ | |
9a0d1e1b AM |
977 | |
978 | int | |
e6cfb550 | 979 | duplicate_eh_handlers (old_note_eh_region, new_note_eh_region, map) |
9a0d1e1b | 980 | int old_note_eh_region, new_note_eh_region; |
3b89e9d1 | 981 | rtx (*map) PARAMS ((rtx)); |
9a0d1e1b AM |
982 | { |
983 | struct handler_info *ptr, *new_ptr; | |
984 | int new_region, region; | |
985 | ||
986 | region = find_func_region (old_note_eh_region); | |
987 | if (region == -1) | |
e6cfb550 AM |
988 | fatal ("Cannot duplicate non-existant exception region."); |
989 | ||
990 | /* duplicate_eh_handlers may have been called during a symbol remap. */ | |
991 | new_region = find_func_region (new_note_eh_region); | |
992 | if (new_region != -1) | |
993 | return (new_region); | |
9a0d1e1b | 994 | |
e6cfb550 | 995 | new_region = new_eh_region_entry (new_note_eh_region, NULL_RTX); |
9a0d1e1b | 996 | |
9a0d1e1b AM |
997 | ptr = function_eh_regions[region].handlers; |
998 | ||
999 | for ( ; ptr; ptr = ptr->next) | |
1000 | { | |
e6cfb550 | 1001 | new_ptr = get_new_handler (map (ptr->handler_label), ptr->type_info); |
9a0d1e1b AM |
1002 | add_new_handler (new_region, new_ptr); |
1003 | } | |
1004 | ||
1005 | return new_region; | |
1006 | } | |
1007 | ||
e6cfb550 AM |
1008 | |
1009 | /* Given a rethrow symbol, find the EH region number this is for. */ | |
1010 | int | |
1011 | eh_region_from_symbol (sym) | |
1012 | rtx sym; | |
1013 | { | |
1014 | int x; | |
1015 | if (sym == last_rethrow_symbol) | |
1016 | return 1; | |
1017 | for (x = 0; x < current_func_eh_entry; x++) | |
1018 | if (function_eh_regions[x].rethrow_label == sym) | |
1019 | return function_eh_regions[x].range_number; | |
1020 | return -1; | |
1021 | } | |
1022 | ||
1023 | ||
1024 | /* When inlining/unrolling, we have to map the symbols passed to | |
1025 | __rethrow as well. This performs the remap. If a symbol isn't foiund, | |
1026 | the original one is returned. This is not an efficient routine, | |
1027 | so don't call it on everything!! */ | |
1028 | rtx | |
1029 | rethrow_symbol_map (sym, map) | |
1030 | rtx sym; | |
3b89e9d1 | 1031 | rtx (*map) PARAMS ((rtx)); |
e6cfb550 AM |
1032 | { |
1033 | int x, y; | |
1034 | for (x = 0; x < current_func_eh_entry; x++) | |
1035 | if (function_eh_regions[x].rethrow_label == sym) | |
1036 | { | |
1037 | /* We've found the original region, now lets determine which region | |
1038 | this now maps to. */ | |
1039 | rtx l1 = function_eh_regions[x].handlers->handler_label; | |
1040 | rtx l2 = map (l1); | |
1041 | y = CODE_LABEL_NUMBER (l2); /* This is the new region number */ | |
1042 | x = find_func_region (y); /* Get the new permanent region */ | |
1043 | if (x == -1) /* Hmm, Doesn't exist yet */ | |
1044 | { | |
1045 | x = duplicate_eh_handlers (CODE_LABEL_NUMBER (l1), y, map); | |
1046 | /* Since we're mapping it, it must be used. */ | |
1047 | SYMBOL_REF_USED (function_eh_regions[x].rethrow_label) = 1; | |
1048 | } | |
1049 | return function_eh_regions[x].rethrow_label; | |
1050 | } | |
1051 | return sym; | |
1052 | } | |
1053 | ||
1054 | int | |
1055 | rethrow_used (region) | |
1056 | int region; | |
1057 | { | |
1058 | if (flag_new_exceptions) | |
1059 | { | |
1060 | rtx lab = function_eh_regions[find_func_region (region)].rethrow_label; | |
1061 | return (SYMBOL_REF_USED (lab)); | |
1062 | } | |
1063 | return 0; | |
1064 | } | |
1065 | ||
4956d07c | 1066 | \f |
38e01259 | 1067 | /* Routine to see if exception handling is turned on. |
4956d07c | 1068 | DO_WARN is non-zero if we want to inform the user that exception |
12670d88 RK |
1069 | handling is turned off. |
1070 | ||
1071 | This is used to ensure that -fexceptions has been specified if the | |
abeeec2a | 1072 | compiler tries to use any exception-specific functions. */ |
4956d07c MS |
1073 | |
1074 | int | |
1075 | doing_eh (do_warn) | |
1076 | int do_warn; | |
1077 | { | |
1078 | if (! flag_exceptions) | |
1079 | { | |
1080 | static int warned = 0; | |
1081 | if (! warned && do_warn) | |
1082 | { | |
1083 | error ("exception handling disabled, use -fexceptions to enable"); | |
1084 | warned = 1; | |
1085 | } | |
1086 | return 0; | |
1087 | } | |
1088 | return 1; | |
1089 | } | |
1090 | ||
12670d88 | 1091 | /* Given a return address in ADDR, determine the address we should use |
abeeec2a | 1092 | to find the corresponding EH region. */ |
4956d07c MS |
1093 | |
1094 | rtx | |
1095 | eh_outer_context (addr) | |
1096 | rtx addr; | |
1097 | { | |
1098 | /* First mask out any unwanted bits. */ | |
1099 | #ifdef MASK_RETURN_ADDR | |
ca55abae | 1100 | expand_and (addr, MASK_RETURN_ADDR, addr); |
4956d07c MS |
1101 | #endif |
1102 | ||
ca55abae JM |
1103 | /* Then adjust to find the real return address. */ |
1104 | #if defined (RETURN_ADDR_OFFSET) | |
1105 | addr = plus_constant (addr, RETURN_ADDR_OFFSET); | |
4956d07c MS |
1106 | #endif |
1107 | ||
1108 | return addr; | |
1109 | } | |
1110 | ||
27a36778 MS |
1111 | /* Start a new exception region for a region of code that has a |
1112 | cleanup action and push the HANDLER for the region onto | |
1113 | protect_list. All of the regions created with add_partial_entry | |
1114 | will be ended when end_protect_partials is invoked. */ | |
12670d88 RK |
1115 | |
1116 | void | |
1117 | add_partial_entry (handler) | |
1118 | tree handler; | |
1119 | { | |
1120 | expand_eh_region_start (); | |
1121 | ||
abeeec2a | 1122 | /* Make sure the entry is on the correct obstack. */ |
12670d88 RK |
1123 | push_obstacks_nochange (); |
1124 | resume_temporary_allocation (); | |
27a36778 MS |
1125 | |
1126 | /* Because this is a cleanup action, we may have to protect the handler | |
1127 | with __terminate. */ | |
1128 | handler = protect_with_terminate (handler); | |
1129 | ||
12670d88 RK |
1130 | protect_list = tree_cons (NULL_TREE, handler, protect_list); |
1131 | pop_obstacks (); | |
1132 | } | |
1133 | ||
100d81d4 | 1134 | /* Emit code to get EH context to current function. */ |
27a36778 | 1135 | |
154bba13 | 1136 | static rtx |
01eb7f9a | 1137 | call_get_eh_context () |
27a36778 | 1138 | { |
bb727b5a JM |
1139 | static tree fn; |
1140 | tree expr; | |
1141 | ||
1142 | if (fn == NULL_TREE) | |
1143 | { | |
1144 | tree fntype; | |
154bba13 | 1145 | fn = get_identifier ("__get_eh_context"); |
bb727b5a JM |
1146 | push_obstacks_nochange (); |
1147 | end_temporary_allocation (); | |
1148 | fntype = build_pointer_type (build_pointer_type | |
1149 | (build_pointer_type (void_type_node))); | |
1150 | fntype = build_function_type (fntype, NULL_TREE); | |
1151 | fn = build_decl (FUNCTION_DECL, fn, fntype); | |
1152 | DECL_EXTERNAL (fn) = 1; | |
1153 | TREE_PUBLIC (fn) = 1; | |
1154 | DECL_ARTIFICIAL (fn) = 1; | |
1155 | TREE_READONLY (fn) = 1; | |
1156 | make_decl_rtl (fn, NULL_PTR, 1); | |
1157 | assemble_external (fn); | |
1158 | pop_obstacks (); | |
1159 | } | |
1160 | ||
1161 | expr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (fn)), fn); | |
1162 | expr = build (CALL_EXPR, TREE_TYPE (TREE_TYPE (fn)), | |
1163 | expr, NULL_TREE, NULL_TREE); | |
1164 | TREE_SIDE_EFFECTS (expr) = 1; | |
bb727b5a | 1165 | |
100d81d4 | 1166 | return copy_to_reg (expand_expr (expr, NULL_RTX, VOIDmode, 0)); |
154bba13 TT |
1167 | } |
1168 | ||
1169 | /* Get a reference to the EH context. | |
1170 | We will only generate a register for the current function EH context here, | |
1171 | and emit a USE insn to mark that this is a EH context register. | |
1172 | ||
1173 | Later, emit_eh_context will emit needed call to __get_eh_context | |
1174 | in libgcc2, and copy the value to the register we have generated. */ | |
1175 | ||
1176 | rtx | |
01eb7f9a | 1177 | get_eh_context () |
154bba13 TT |
1178 | { |
1179 | if (current_function_ehc == 0) | |
1180 | { | |
1181 | rtx insn; | |
1182 | ||
1183 | current_function_ehc = gen_reg_rtx (Pmode); | |
1184 | ||
38a448ca RH |
1185 | insn = gen_rtx_USE (GET_MODE (current_function_ehc), |
1186 | current_function_ehc); | |
154bba13 TT |
1187 | insn = emit_insn_before (insn, get_first_nonparm_insn ()); |
1188 | ||
1189 | REG_NOTES (insn) | |
38a448ca RH |
1190 | = gen_rtx_EXPR_LIST (REG_EH_CONTEXT, current_function_ehc, |
1191 | REG_NOTES (insn)); | |
154bba13 TT |
1192 | } |
1193 | return current_function_ehc; | |
1194 | } | |
1195 | ||
154bba13 TT |
1196 | /* Get a reference to the dynamic handler chain. It points to the |
1197 | pointer to the next element in the dynamic handler chain. It ends | |
1198 | when there are no more elements in the dynamic handler chain, when | |
1199 | the value is &top_elt from libgcc2.c. Immediately after the | |
1200 | pointer, is an area suitable for setjmp/longjmp when | |
1201 | DONT_USE_BUILTIN_SETJMP is defined, and an area suitable for | |
1202 | __builtin_setjmp/__builtin_longjmp when DONT_USE_BUILTIN_SETJMP | |
1203 | isn't defined. */ | |
1204 | ||
1205 | rtx | |
1206 | get_dynamic_handler_chain () | |
1207 | { | |
1208 | rtx ehc, dhc, result; | |
1209 | ||
01eb7f9a | 1210 | ehc = get_eh_context (); |
3301dc51 AM |
1211 | |
1212 | /* This is the offset of dynamic_handler_chain in the eh_context struct | |
1213 | declared in eh-common.h. If its location is change, change this offset */ | |
5816cb14 | 1214 | dhc = plus_constant (ehc, POINTER_SIZE / BITS_PER_UNIT); |
154bba13 TT |
1215 | |
1216 | result = copy_to_reg (dhc); | |
1217 | ||
1218 | /* We don't want a copy of the dcc, but rather, the single dcc. */ | |
38a448ca | 1219 | return gen_rtx_MEM (Pmode, result); |
27a36778 MS |
1220 | } |
1221 | ||
1222 | /* Get a reference to the dynamic cleanup chain. It points to the | |
1223 | pointer to the next element in the dynamic cleanup chain. | |
1224 | Immediately after the pointer, are two Pmode variables, one for a | |
1225 | pointer to a function that performs the cleanup action, and the | |
1226 | second, the argument to pass to that function. */ | |
1227 | ||
1228 | rtx | |
1229 | get_dynamic_cleanup_chain () | |
1230 | { | |
154bba13 | 1231 | rtx dhc, dcc, result; |
27a36778 MS |
1232 | |
1233 | dhc = get_dynamic_handler_chain (); | |
5816cb14 | 1234 | dcc = plus_constant (dhc, POINTER_SIZE / BITS_PER_UNIT); |
27a36778 | 1235 | |
154bba13 | 1236 | result = copy_to_reg (dcc); |
27a36778 MS |
1237 | |
1238 | /* We don't want a copy of the dcc, but rather, the single dcc. */ | |
38a448ca | 1239 | return gen_rtx_MEM (Pmode, result); |
154bba13 TT |
1240 | } |
1241 | ||
767f5b14 | 1242 | #ifdef DONT_USE_BUILTIN_SETJMP |
27a36778 MS |
1243 | /* Generate code to evaluate X and jump to LABEL if the value is nonzero. |
1244 | LABEL is an rtx of code CODE_LABEL, in this function. */ | |
1245 | ||
561592c5 | 1246 | static void |
27a36778 MS |
1247 | jumpif_rtx (x, label) |
1248 | rtx x; | |
1249 | rtx label; | |
1250 | { | |
1251 | jumpif (make_tree (type_for_mode (GET_MODE (x), 0), x), label); | |
1252 | } | |
767f5b14 | 1253 | #endif |
27a36778 MS |
1254 | |
1255 | /* Start a dynamic cleanup on the EH runtime dynamic cleanup stack. | |
1256 | We just need to create an element for the cleanup list, and push it | |
1257 | into the chain. | |
1258 | ||
1259 | A dynamic cleanup is a cleanup action implied by the presence of an | |
1260 | element on the EH runtime dynamic cleanup stack that is to be | |
1261 | performed when an exception is thrown. The cleanup action is | |
1262 | performed by __sjthrow when an exception is thrown. Only certain | |
1263 | actions can be optimized into dynamic cleanup actions. For the | |
1264 | restrictions on what actions can be performed using this routine, | |
1265 | see expand_eh_region_start_tree. */ | |
1266 | ||
1267 | static void | |
1268 | start_dynamic_cleanup (func, arg) | |
1269 | tree func; | |
1270 | tree arg; | |
1271 | { | |
381127e8 | 1272 | rtx dcc; |
27a36778 MS |
1273 | rtx new_func, new_arg; |
1274 | rtx x, buf; | |
1275 | int size; | |
1276 | ||
1277 | /* We allocate enough room for a pointer to the function, and | |
1278 | one argument. */ | |
1279 | size = 2; | |
1280 | ||
1281 | /* XXX, FIXME: The stack space allocated this way is too long lived, | |
1282 | but there is no allocation routine that allocates at the level of | |
1283 | the last binding contour. */ | |
1284 | buf = assign_stack_local (BLKmode, | |
1285 | GET_MODE_SIZE (Pmode)*(size+1), | |
1286 | 0); | |
1287 | ||
1288 | buf = change_address (buf, Pmode, NULL_RTX); | |
1289 | ||
1290 | /* Store dcc into the first word of the newly allocated buffer. */ | |
1291 | ||
1292 | dcc = get_dynamic_cleanup_chain (); | |
1293 | emit_move_insn (buf, dcc); | |
1294 | ||
1295 | /* Store func and arg into the cleanup list element. */ | |
1296 | ||
38a448ca RH |
1297 | new_func = gen_rtx_MEM (Pmode, plus_constant (XEXP (buf, 0), |
1298 | GET_MODE_SIZE (Pmode))); | |
1299 | new_arg = gen_rtx_MEM (Pmode, plus_constant (XEXP (buf, 0), | |
1300 | GET_MODE_SIZE (Pmode)*2)); | |
27a36778 MS |
1301 | x = expand_expr (func, new_func, Pmode, 0); |
1302 | if (x != new_func) | |
1303 | emit_move_insn (new_func, x); | |
1304 | ||
1305 | x = expand_expr (arg, new_arg, Pmode, 0); | |
1306 | if (x != new_arg) | |
1307 | emit_move_insn (new_arg, x); | |
1308 | ||
1309 | /* Update the cleanup chain. */ | |
1310 | ||
1311 | emit_move_insn (dcc, XEXP (buf, 0)); | |
1312 | } | |
1313 | ||
1314 | /* Emit RTL to start a dynamic handler on the EH runtime dynamic | |
1315 | handler stack. This should only be used by expand_eh_region_start | |
1316 | or expand_eh_region_start_tree. */ | |
1317 | ||
1318 | static void | |
1319 | start_dynamic_handler () | |
1320 | { | |
1321 | rtx dhc, dcc; | |
6e6a07d2 | 1322 | rtx x, arg, buf; |
27a36778 MS |
1323 | int size; |
1324 | ||
6e6a07d2 | 1325 | #ifndef DONT_USE_BUILTIN_SETJMP |
27a36778 MS |
1326 | /* The number of Pmode words for the setjmp buffer, when using the |
1327 | builtin setjmp/longjmp, see expand_builtin, case | |
1328 | BUILT_IN_LONGJMP. */ | |
1329 | size = 5; | |
1330 | #else | |
1331 | #ifdef JMP_BUF_SIZE | |
1332 | size = JMP_BUF_SIZE; | |
1333 | #else | |
1334 | /* Should be large enough for most systems, if it is not, | |
1335 | JMP_BUF_SIZE should be defined with the proper value. It will | |
1336 | also tend to be larger than necessary for most systems, a more | |
1337 | optimal port will define JMP_BUF_SIZE. */ | |
1338 | size = FIRST_PSEUDO_REGISTER+2; | |
1339 | #endif | |
1340 | #endif | |
1341 | /* XXX, FIXME: The stack space allocated this way is too long lived, | |
1342 | but there is no allocation routine that allocates at the level of | |
1343 | the last binding contour. */ | |
1344 | arg = assign_stack_local (BLKmode, | |
1345 | GET_MODE_SIZE (Pmode)*(size+1), | |
1346 | 0); | |
1347 | ||
1348 | arg = change_address (arg, Pmode, NULL_RTX); | |
1349 | ||
1350 | /* Store dhc into the first word of the newly allocated buffer. */ | |
1351 | ||
1352 | dhc = get_dynamic_handler_chain (); | |
38a448ca RH |
1353 | dcc = gen_rtx_MEM (Pmode, plus_constant (XEXP (arg, 0), |
1354 | GET_MODE_SIZE (Pmode))); | |
27a36778 MS |
1355 | emit_move_insn (arg, dhc); |
1356 | ||
1357 | /* Zero out the start of the cleanup chain. */ | |
1358 | emit_move_insn (dcc, const0_rtx); | |
1359 | ||
1360 | /* The jmpbuf starts two words into the area allocated. */ | |
6e6a07d2 | 1361 | buf = plus_constant (XEXP (arg, 0), GET_MODE_SIZE (Pmode)*2); |
27a36778 | 1362 | |
6e6a07d2 | 1363 | #ifdef DONT_USE_BUILTIN_SETJMP |
27a36778 | 1364 | x = emit_library_call_value (setjmp_libfunc, NULL_RTX, 1, SImode, 1, |
6e6a07d2 | 1365 | buf, Pmode); |
6fd1c67b RH |
1366 | /* If we come back here for a catch, transfer control to the handler. */ |
1367 | jumpif_rtx (x, ehstack.top->entry->exception_handler_label); | |
6e6a07d2 | 1368 | #else |
6fd1c67b RH |
1369 | { |
1370 | /* A label to continue execution for the no exception case. */ | |
1371 | rtx noex = gen_label_rtx(); | |
1372 | x = expand_builtin_setjmp (buf, NULL_RTX, noex, | |
1373 | ehstack.top->entry->exception_handler_label); | |
1374 | emit_label (noex); | |
1375 | } | |
6e6a07d2 | 1376 | #endif |
27a36778 | 1377 | |
27a36778 MS |
1378 | /* We are committed to this, so update the handler chain. */ |
1379 | ||
1380 | emit_move_insn (dhc, XEXP (arg, 0)); | |
1381 | } | |
1382 | ||
1383 | /* Start an exception handling region for the given cleanup action. | |
12670d88 | 1384 | All instructions emitted after this point are considered to be part |
27a36778 MS |
1385 | of the region until expand_eh_region_end is invoked. CLEANUP is |
1386 | the cleanup action to perform. The return value is true if the | |
1387 | exception region was optimized away. If that case, | |
1388 | expand_eh_region_end does not need to be called for this cleanup, | |
1389 | nor should it be. | |
1390 | ||
1391 | This routine notices one particular common case in C++ code | |
1392 | generation, and optimizes it so as to not need the exception | |
1393 | region. It works by creating a dynamic cleanup action, instead of | |
38e01259 | 1394 | a using an exception region. */ |
27a36778 MS |
1395 | |
1396 | int | |
4c581243 MS |
1397 | expand_eh_region_start_tree (decl, cleanup) |
1398 | tree decl; | |
27a36778 MS |
1399 | tree cleanup; |
1400 | { | |
27a36778 MS |
1401 | /* This is the old code. */ |
1402 | if (! doing_eh (0)) | |
1403 | return 0; | |
1404 | ||
1405 | /* The optimization only applies to actions protected with | |
1406 | terminate, and only applies if we are using the setjmp/longjmp | |
1407 | codegen method. */ | |
1408 | if (exceptions_via_longjmp | |
1409 | && protect_cleanup_actions_with_terminate) | |
1410 | { | |
1411 | tree func, arg; | |
1412 | tree args; | |
1413 | ||
1414 | /* Ignore any UNSAVE_EXPR. */ | |
1415 | if (TREE_CODE (cleanup) == UNSAVE_EXPR) | |
1416 | cleanup = TREE_OPERAND (cleanup, 0); | |
1417 | ||
1418 | /* Further, it only applies if the action is a call, if there | |
1419 | are 2 arguments, and if the second argument is 2. */ | |
1420 | ||
1421 | if (TREE_CODE (cleanup) == CALL_EXPR | |
1422 | && (args = TREE_OPERAND (cleanup, 1)) | |
1423 | && (func = TREE_OPERAND (cleanup, 0)) | |
1424 | && (arg = TREE_VALUE (args)) | |
1425 | && (args = TREE_CHAIN (args)) | |
1426 | ||
1427 | /* is the second argument 2? */ | |
1428 | && TREE_CODE (TREE_VALUE (args)) == INTEGER_CST | |
1429 | && TREE_INT_CST_LOW (TREE_VALUE (args)) == 2 | |
1430 | && TREE_INT_CST_HIGH (TREE_VALUE (args)) == 0 | |
1431 | ||
1432 | /* Make sure there are no other arguments. */ | |
1433 | && TREE_CHAIN (args) == NULL_TREE) | |
1434 | { | |
1435 | /* Arrange for returns and gotos to pop the entry we make on the | |
1436 | dynamic cleanup stack. */ | |
4c581243 | 1437 | expand_dcc_cleanup (decl); |
27a36778 MS |
1438 | start_dynamic_cleanup (func, arg); |
1439 | return 1; | |
1440 | } | |
1441 | } | |
1442 | ||
4c581243 | 1443 | expand_eh_region_start_for_decl (decl); |
9762d48d | 1444 | ehstack.top->entry->finalization = cleanup; |
27a36778 MS |
1445 | |
1446 | return 0; | |
1447 | } | |
1448 | ||
4c581243 MS |
1449 | /* Just like expand_eh_region_start, except if a cleanup action is |
1450 | entered on the cleanup chain, the TREE_PURPOSE of the element put | |
1451 | on the chain is DECL. DECL should be the associated VAR_DECL, if | |
1452 | any, otherwise it should be NULL_TREE. */ | |
4956d07c MS |
1453 | |
1454 | void | |
4c581243 MS |
1455 | expand_eh_region_start_for_decl (decl) |
1456 | tree decl; | |
4956d07c MS |
1457 | { |
1458 | rtx note; | |
1459 | ||
1460 | /* This is the old code. */ | |
1461 | if (! doing_eh (0)) | |
1462 | return; | |
1463 | ||
27a36778 MS |
1464 | if (exceptions_via_longjmp) |
1465 | { | |
1466 | /* We need a new block to record the start and end of the | |
1467 | dynamic handler chain. We could always do this, but we | |
1468 | really want to permit jumping into such a block, and we want | |
1469 | to avoid any errors or performance impact in the SJ EH code | |
1470 | for now. */ | |
1471 | expand_start_bindings (0); | |
1472 | ||
1473 | /* But we don't need or want a new temporary level. */ | |
1474 | pop_temp_slots (); | |
1475 | ||
1476 | /* Mark this block as created by expand_eh_region_start. This | |
1477 | is so that we can pop the block with expand_end_bindings | |
1478 | automatically. */ | |
1479 | mark_block_as_eh_region (); | |
1480 | ||
1481 | /* Arrange for returns and gotos to pop the entry we make on the | |
1482 | dynamic handler stack. */ | |
4c581243 | 1483 | expand_dhc_cleanup (decl); |
27a36778 | 1484 | } |
4956d07c | 1485 | |
478b0752 | 1486 | push_eh_entry (&ehstack); |
9ad8a5f0 MS |
1487 | note = emit_note (NULL_PTR, NOTE_INSN_EH_REGION_BEG); |
1488 | NOTE_BLOCK_NUMBER (note) | |
1489 | = CODE_LABEL_NUMBER (ehstack.top->entry->exception_handler_label); | |
27a36778 MS |
1490 | if (exceptions_via_longjmp) |
1491 | start_dynamic_handler (); | |
4956d07c MS |
1492 | } |
1493 | ||
4c581243 MS |
1494 | /* Start an exception handling region. All instructions emitted after |
1495 | this point are considered to be part of the region until | |
1496 | expand_eh_region_end is invoked. */ | |
1497 | ||
1498 | void | |
1499 | expand_eh_region_start () | |
1500 | { | |
1501 | expand_eh_region_start_for_decl (NULL_TREE); | |
1502 | } | |
1503 | ||
27a36778 MS |
1504 | /* End an exception handling region. The information about the region |
1505 | is found on the top of ehstack. | |
12670d88 RK |
1506 | |
1507 | HANDLER is either the cleanup for the exception region, or if we're | |
1508 | marking the end of a try block, HANDLER is integer_zero_node. | |
1509 | ||
27a36778 | 1510 | HANDLER will be transformed to rtl when expand_leftover_cleanups |
abeeec2a | 1511 | is invoked. */ |
4956d07c MS |
1512 | |
1513 | void | |
1514 | expand_eh_region_end (handler) | |
1515 | tree handler; | |
1516 | { | |
4956d07c | 1517 | struct eh_entry *entry; |
9ad8a5f0 | 1518 | rtx note; |
e6cfb550 | 1519 | int ret, r; |
4956d07c MS |
1520 | |
1521 | if (! doing_eh (0)) | |
1522 | return; | |
1523 | ||
1524 | entry = pop_eh_entry (&ehstack); | |
1525 | ||
9ad8a5f0 | 1526 | note = emit_note (NULL_PTR, NOTE_INSN_EH_REGION_END); |
e6cfb550 | 1527 | ret = NOTE_BLOCK_NUMBER (note) |
9ad8a5f0 | 1528 | = CODE_LABEL_NUMBER (entry->exception_handler_label); |
e6cfb550 | 1529 | if (exceptions_via_longjmp == 0 && ! flag_new_exceptions |
e701eb4d JM |
1530 | /* We share outer_context between regions; only emit it once. */ |
1531 | && INSN_UID (entry->outer_context) == 0) | |
27a36778 | 1532 | { |
478b0752 | 1533 | rtx label; |
4956d07c | 1534 | |
478b0752 MS |
1535 | label = gen_label_rtx (); |
1536 | emit_jump (label); | |
1537 | ||
1538 | /* Emit a label marking the end of this exception region that | |
1539 | is used for rethrowing into the outer context. */ | |
1540 | emit_label (entry->outer_context); | |
e701eb4d | 1541 | expand_internal_throw (); |
4956d07c | 1542 | |
478b0752 | 1543 | emit_label (label); |
27a36778 | 1544 | } |
4956d07c MS |
1545 | |
1546 | entry->finalization = handler; | |
1547 | ||
9a0d1e1b | 1548 | /* create region entry in final exception table */ |
e6cfb550 | 1549 | r = new_eh_region_entry (NOTE_BLOCK_NUMBER (note), entry->rethrow_label); |
9a0d1e1b | 1550 | |
4956d07c MS |
1551 | enqueue_eh_entry (&ehqueue, entry); |
1552 | ||
27a36778 MS |
1553 | /* If we have already started ending the bindings, don't recurse. |
1554 | This only happens when exceptions_via_longjmp is true. */ | |
1555 | if (is_eh_region ()) | |
1556 | { | |
1557 | /* Because we don't need or want a new temporary level and | |
1558 | because we didn't create one in expand_eh_region_start, | |
1559 | create a fake one now to avoid removing one in | |
1560 | expand_end_bindings. */ | |
1561 | push_temp_slots (); | |
1562 | ||
1563 | mark_block_as_not_eh_region (); | |
1564 | ||
1565 | /* Maybe do this to prevent jumping in and so on... */ | |
1566 | expand_end_bindings (NULL_TREE, 0, 0); | |
1567 | } | |
4956d07c MS |
1568 | } |
1569 | ||
9762d48d JM |
1570 | /* End the EH region for a goto fixup. We only need them in the region-based |
1571 | EH scheme. */ | |
1572 | ||
1573 | void | |
1574 | expand_fixup_region_start () | |
1575 | { | |
1576 | if (! doing_eh (0) || exceptions_via_longjmp) | |
1577 | return; | |
1578 | ||
1579 | expand_eh_region_start (); | |
1580 | } | |
1581 | ||
1582 | /* End the EH region for a goto fixup. CLEANUP is the cleanup we just | |
1583 | expanded; to avoid running it twice if it throws, we look through the | |
1584 | ehqueue for a matching region and rethrow from its outer_context. */ | |
1585 | ||
1586 | void | |
1587 | expand_fixup_region_end (cleanup) | |
1588 | tree cleanup; | |
1589 | { | |
9762d48d | 1590 | struct eh_node *node; |
b37f006b | 1591 | int dont_issue; |
9762d48d JM |
1592 | |
1593 | if (! doing_eh (0) || exceptions_via_longjmp) | |
1594 | return; | |
1595 | ||
1596 | for (node = ehstack.top; node && node->entry->finalization != cleanup; ) | |
1597 | node = node->chain; | |
1598 | if (node == 0) | |
1599 | for (node = ehqueue.head; node && node->entry->finalization != cleanup; ) | |
1600 | node = node->chain; | |
1601 | if (node == 0) | |
1602 | abort (); | |
1603 | ||
b37f006b AM |
1604 | /* If the outer context label has not been issued yet, we don't want |
1605 | to issue it as a part of this region, unless this is the | |
1606 | correct region for the outer context. If we did, then the label for | |
1607 | the outer context will be WITHIN the begin/end labels, | |
1608 | and we could get an infinte loop when it tried to rethrow, or just | |
1609 | generally incorrect execution following a throw. */ | |
1610 | ||
1611 | dont_issue = ((INSN_UID (node->entry->outer_context) == 0) | |
1612 | && (ehstack.top->entry != node->entry)); | |
1613 | ||
e701eb4d | 1614 | ehstack.top->entry->outer_context = node->entry->outer_context; |
9762d48d | 1615 | |
b37f006b AM |
1616 | /* Since we are rethrowing to the OUTER region, we know we don't need |
1617 | a jump around sequence for this region, so we'll pretend the outer | |
1618 | context label has been issued by setting INSN_UID to 1, then clearing | |
1619 | it again afterwards. */ | |
1620 | ||
1621 | if (dont_issue) | |
1622 | INSN_UID (node->entry->outer_context) = 1; | |
1623 | ||
e701eb4d JM |
1624 | /* Just rethrow. size_zero_node is just a NOP. */ |
1625 | expand_eh_region_end (size_zero_node); | |
b37f006b AM |
1626 | |
1627 | if (dont_issue) | |
1628 | INSN_UID (node->entry->outer_context) = 0; | |
9762d48d JM |
1629 | } |
1630 | ||
27a36778 MS |
1631 | /* If we are using the setjmp/longjmp EH codegen method, we emit a |
1632 | call to __sjthrow. | |
1633 | ||
1634 | Otherwise, we emit a call to __throw and note that we threw | |
1635 | something, so we know we need to generate the necessary code for | |
1636 | __throw. | |
12670d88 RK |
1637 | |
1638 | Before invoking throw, the __eh_pc variable must have been set up | |
1639 | to contain the PC being thrown from. This address is used by | |
27a36778 | 1640 | __throw to determine which exception region (if any) is |
abeeec2a | 1641 | responsible for handling the exception. */ |
4956d07c | 1642 | |
27a36778 | 1643 | void |
4956d07c MS |
1644 | emit_throw () |
1645 | { | |
27a36778 MS |
1646 | if (exceptions_via_longjmp) |
1647 | { | |
1648 | emit_library_call (sjthrow_libfunc, 0, VOIDmode, 0); | |
1649 | } | |
1650 | else | |
1651 | { | |
4956d07c | 1652 | #ifdef JUMP_TO_THROW |
27a36778 | 1653 | emit_indirect_jump (throw_libfunc); |
4956d07c | 1654 | #else |
27a36778 | 1655 | emit_library_call (throw_libfunc, 0, VOIDmode, 0); |
4956d07c | 1656 | #endif |
27a36778 | 1657 | } |
4956d07c MS |
1658 | emit_barrier (); |
1659 | } | |
1660 | ||
e701eb4d JM |
1661 | /* Throw the current exception. If appropriate, this is done by jumping |
1662 | to the next handler. */ | |
4956d07c MS |
1663 | |
1664 | void | |
e701eb4d | 1665 | expand_internal_throw () |
4956d07c | 1666 | { |
e701eb4d | 1667 | emit_throw (); |
4956d07c MS |
1668 | } |
1669 | ||
1670 | /* Called from expand_exception_blocks and expand_end_catch_block to | |
27a36778 | 1671 | emit any pending handlers/cleanups queued from expand_eh_region_end. */ |
4956d07c MS |
1672 | |
1673 | void | |
1674 | expand_leftover_cleanups () | |
1675 | { | |
1676 | struct eh_entry *entry; | |
1677 | ||
1678 | while ((entry = dequeue_eh_entry (&ehqueue)) != 0) | |
1679 | { | |
1680 | rtx prev; | |
1681 | ||
12670d88 RK |
1682 | /* A leftover try block. Shouldn't be one here. */ |
1683 | if (entry->finalization == integer_zero_node) | |
1684 | abort (); | |
1685 | ||
abeeec2a | 1686 | /* Output the label for the start of the exception handler. */ |
4956d07c | 1687 | |
9a0d1e1b | 1688 | receive_exception_label (entry->exception_handler_label); |
f51430ed | 1689 | |
9a0d1e1b AM |
1690 | /* register a handler for this cleanup region */ |
1691 | add_new_handler ( | |
1692 | find_func_region (CODE_LABEL_NUMBER (entry->exception_handler_label)), | |
1693 | get_new_handler (entry->exception_handler_label, NULL)); | |
05f5b2cd | 1694 | |
abeeec2a | 1695 | /* And now generate the insns for the handler. */ |
4956d07c MS |
1696 | expand_expr (entry->finalization, const0_rtx, VOIDmode, 0); |
1697 | ||
1698 | prev = get_last_insn (); | |
27a36778 | 1699 | if (prev == NULL || GET_CODE (prev) != BARRIER) |
e701eb4d JM |
1700 | /* Emit code to throw to the outer context if we fall off |
1701 | the end of the handler. */ | |
1702 | expand_rethrow (entry->outer_context); | |
4956d07c | 1703 | |
c7ae64f2 | 1704 | do_pending_stack_adjust (); |
4956d07c MS |
1705 | free (entry); |
1706 | } | |
1707 | } | |
1708 | ||
abeeec2a | 1709 | /* Called at the start of a block of try statements. */ |
12670d88 RK |
1710 | void |
1711 | expand_start_try_stmts () | |
1712 | { | |
1713 | if (! doing_eh (1)) | |
1714 | return; | |
1715 | ||
1716 | expand_eh_region_start (); | |
1717 | } | |
1718 | ||
9a0d1e1b AM |
1719 | /* Called to begin a catch clause. The parameter is the object which |
1720 | will be passed to the runtime type check routine. */ | |
1721 | void | |
0d3453df | 1722 | start_catch_handler (rtime) |
9a0d1e1b AM |
1723 | tree rtime; |
1724 | { | |
9a9deafc AM |
1725 | rtx handler_label; |
1726 | int insn_region_num; | |
1727 | int eh_region_entry; | |
1728 | ||
1729 | if (! doing_eh (1)) | |
1730 | return; | |
1731 | ||
1732 | handler_label = catchstack.top->entry->exception_handler_label; | |
1733 | insn_region_num = CODE_LABEL_NUMBER (handler_label); | |
1734 | eh_region_entry = find_func_region (insn_region_num); | |
9a0d1e1b AM |
1735 | |
1736 | /* If we've already issued this label, pick a new one */ | |
7ecb5d27 | 1737 | if (catchstack.top->entry->label_used) |
9a0d1e1b AM |
1738 | handler_label = gen_exception_label (); |
1739 | else | |
1740 | catchstack.top->entry->label_used = 1; | |
1741 | ||
1742 | receive_exception_label (handler_label); | |
1743 | ||
1744 | add_new_handler (eh_region_entry, get_new_handler (handler_label, rtime)); | |
bf71cd2e AM |
1745 | |
1746 | if (flag_new_exceptions && ! exceptions_via_longjmp) | |
1747 | return; | |
1748 | ||
1749 | /* Under the old mechanism, as well as setjmp/longjmp, we need to | |
1750 | issue code to compare 'rtime' to the value in eh_info, via the | |
1751 | matching function in eh_info. If its is false, we branch around | |
1752 | the handler we are about to issue. */ | |
1753 | ||
1754 | if (rtime != NULL_TREE && rtime != CATCH_ALL_TYPE) | |
1755 | { | |
1756 | rtx call_rtx, rtime_address; | |
1757 | ||
1758 | if (catchstack.top->entry->false_label != NULL_RTX) | |
7ac2148b | 1759 | fatal ("Compiler Bug: Never issued previous false_label"); |
bf71cd2e AM |
1760 | catchstack.top->entry->false_label = gen_exception_label (); |
1761 | ||
1762 | rtime_address = expand_expr (rtime, NULL_RTX, Pmode, EXPAND_INITIALIZER); | |
1763 | rtime_address = force_reg (Pmode, rtime_address); | |
1764 | ||
1765 | /* Now issue the call, and branch around handler if needed */ | |
43566944 AM |
1766 | call_rtx = emit_library_call_value (eh_rtime_match_libfunc, NULL_RTX, |
1767 | 0, SImode, 1, rtime_address, Pmode); | |
bf71cd2e AM |
1768 | |
1769 | /* Did the function return true? */ | |
1770 | emit_cmp_insn (call_rtx, const0_rtx, EQ, NULL_RTX, | |
1771 | GET_MODE (call_rtx), 0 ,0); | |
1772 | emit_jump_insn (gen_beq (catchstack.top->entry->false_label)); | |
1773 | } | |
1774 | } | |
1775 | ||
1776 | /* Called to end a catch clause. If we aren't using the new exception | |
1777 | model tabel mechanism, we need to issue the branch-around label | |
1778 | for the end of the catch block. */ | |
1779 | ||
1780 | void | |
1781 | end_catch_handler () | |
1782 | { | |
e6cfb550 | 1783 | if (! doing_eh (1)) |
bf71cd2e | 1784 | return; |
e6cfb550 AM |
1785 | |
1786 | if (flag_new_exceptions && ! exceptions_via_longjmp) | |
1787 | { | |
1788 | emit_barrier (); | |
1789 | return; | |
1790 | } | |
bf71cd2e AM |
1791 | |
1792 | /* A NULL label implies the catch clause was a catch all or cleanup */ | |
1793 | if (catchstack.top->entry->false_label == NULL_RTX) | |
1794 | return; | |
1795 | ||
1796 | emit_label (catchstack.top->entry->false_label); | |
1797 | catchstack.top->entry->false_label = NULL_RTX; | |
9a0d1e1b AM |
1798 | } |
1799 | ||
12670d88 RK |
1800 | /* Generate RTL for the start of a group of catch clauses. |
1801 | ||
1802 | It is responsible for starting a new instruction sequence for the | |
1803 | instructions in the catch block, and expanding the handlers for the | |
1804 | internally-generated exception regions nested within the try block | |
abeeec2a | 1805 | corresponding to this catch block. */ |
4956d07c MS |
1806 | |
1807 | void | |
1808 | expand_start_all_catch () | |
1809 | { | |
1810 | struct eh_entry *entry; | |
1811 | tree label; | |
e701eb4d | 1812 | rtx outer_context; |
4956d07c MS |
1813 | |
1814 | if (! doing_eh (1)) | |
1815 | return; | |
1816 | ||
e701eb4d | 1817 | outer_context = ehstack.top->entry->outer_context; |
1418bb67 | 1818 | |
abeeec2a | 1819 | /* End the try block. */ |
12670d88 RK |
1820 | expand_eh_region_end (integer_zero_node); |
1821 | ||
4956d07c MS |
1822 | emit_line_note (input_filename, lineno); |
1823 | label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE); | |
1824 | ||
12670d88 | 1825 | /* The label for the exception handling block that we will save. |
956d6950 | 1826 | This is Lresume in the documentation. */ |
4956d07c MS |
1827 | expand_label (label); |
1828 | ||
12670d88 | 1829 | /* Push the label that points to where normal flow is resumed onto |
abeeec2a | 1830 | the top of the label stack. */ |
4956d07c MS |
1831 | push_label_entry (&caught_return_label_stack, NULL_RTX, label); |
1832 | ||
1833 | /* Start a new sequence for all the catch blocks. We will add this | |
12670d88 | 1834 | to the global sequence catch_clauses when we have completed all |
4956d07c MS |
1835 | the handlers in this handler-seq. */ |
1836 | start_sequence (); | |
1837 | ||
9a0d1e1b AM |
1838 | entry = dequeue_eh_entry (&ehqueue); |
1839 | for ( ; entry->finalization != integer_zero_node; | |
1840 | entry = dequeue_eh_entry (&ehqueue)) | |
4956d07c MS |
1841 | { |
1842 | rtx prev; | |
1843 | ||
9a0d1e1b | 1844 | /* Emit the label for the cleanup handler for this region, and |
12670d88 RK |
1845 | expand the code for the handler. |
1846 | ||
1847 | Note that a catch region is handled as a side-effect here; | |
1848 | for a try block, entry->finalization will contain | |
1849 | integer_zero_node, so no code will be generated in the | |
1850 | expand_expr call below. But, the label for the handler will | |
1851 | still be emitted, so any code emitted after this point will | |
abeeec2a | 1852 | end up being the handler. */ |
9a0d1e1b AM |
1853 | |
1854 | receive_exception_label (entry->exception_handler_label); | |
05f5b2cd | 1855 | |
9a0d1e1b AM |
1856 | /* register a handler for this cleanup region */ |
1857 | add_new_handler ( | |
1858 | find_func_region (CODE_LABEL_NUMBER (entry->exception_handler_label)), | |
1859 | get_new_handler (entry->exception_handler_label, NULL)); | |
4956d07c | 1860 | |
9a0d1e1b | 1861 | /* And now generate the insns for the cleanup handler. */ |
27a36778 MS |
1862 | expand_expr (entry->finalization, const0_rtx, VOIDmode, 0); |
1863 | ||
4956d07c | 1864 | prev = get_last_insn (); |
12670d88 | 1865 | if (prev == NULL || GET_CODE (prev) != BARRIER) |
e701eb4d JM |
1866 | /* Code to throw out to outer context when we fall off end |
1867 | of the handler. We can't do this here for catch blocks, | |
1868 | so it's done in expand_end_all_catch instead. */ | |
1869 | expand_rethrow (entry->outer_context); | |
12670d88 | 1870 | |
f45ebe47 | 1871 | do_pending_stack_adjust (); |
4956d07c MS |
1872 | free (entry); |
1873 | } | |
e701eb4d | 1874 | |
9a0d1e1b AM |
1875 | /* At this point, all the cleanups are done, and the ehqueue now has |
1876 | the current exception region at its head. We dequeue it, and put it | |
1877 | on the catch stack. */ | |
1878 | ||
1879 | push_entry (&catchstack, entry); | |
1880 | ||
e701eb4d JM |
1881 | /* If we are not doing setjmp/longjmp EH, because we are reordered |
1882 | out of line, we arrange to rethrow in the outer context. We need to | |
1883 | do this because we are not physically within the region, if any, that | |
1884 | logically contains this catch block. */ | |
1885 | if (! exceptions_via_longjmp) | |
1886 | { | |
1887 | expand_eh_region_start (); | |
1888 | ehstack.top->entry->outer_context = outer_context; | |
1889 | } | |
5816cb14 | 1890 | |
4956d07c MS |
1891 | } |
1892 | ||
12670d88 RK |
1893 | /* Finish up the catch block. At this point all the insns for the |
1894 | catch clauses have already been generated, so we only have to add | |
1895 | them to the catch_clauses list. We also want to make sure that if | |
1896 | we fall off the end of the catch clauses that we rethrow to the | |
abeeec2a | 1897 | outer EH region. */ |
4956d07c MS |
1898 | |
1899 | void | |
1900 | expand_end_all_catch () | |
1901 | { | |
e6cfb550 | 1902 | rtx new_catch_clause; |
0d3453df | 1903 | struct eh_entry *entry; |
4956d07c MS |
1904 | |
1905 | if (! doing_eh (1)) | |
1906 | return; | |
1907 | ||
0d3453df AM |
1908 | /* Dequeue the current catch clause region. */ |
1909 | entry = pop_eh_entry (&catchstack); | |
1910 | free (entry); | |
1911 | ||
e701eb4d | 1912 | if (! exceptions_via_longjmp) |
5dfa7520 | 1913 | { |
e6cfb550 | 1914 | rtx outer_context = ehstack.top->entry->outer_context; |
5dfa7520 JM |
1915 | |
1916 | /* Finish the rethrow region. size_zero_node is just a NOP. */ | |
1917 | expand_eh_region_end (size_zero_node); | |
e6cfb550 AM |
1918 | /* New exceptions handling models will never have a fall through |
1919 | of a catch clause */ | |
1920 | if (!flag_new_exceptions) | |
1921 | expand_rethrow (outer_context); | |
5dfa7520 | 1922 | } |
e6cfb550 AM |
1923 | else |
1924 | expand_rethrow (NULL_RTX); | |
5dfa7520 | 1925 | |
e701eb4d JM |
1926 | /* Code to throw out to outer context, if we fall off end of catch |
1927 | handlers. This is rethrow (Lresume, same id, same obj) in the | |
1928 | documentation. We use Lresume because we know that it will throw | |
1929 | to the correct context. | |
12670d88 | 1930 | |
e701eb4d JM |
1931 | In other words, if the catch handler doesn't exit or return, we |
1932 | do a "throw" (using the address of Lresume as the point being | |
1933 | thrown from) so that the outer EH region can then try to process | |
1934 | the exception. */ | |
4956d07c MS |
1935 | |
1936 | /* Now we have the complete catch sequence. */ | |
1937 | new_catch_clause = get_insns (); | |
1938 | end_sequence (); | |
1939 | ||
1940 | /* This level of catch blocks is done, so set up the successful | |
1941 | catch jump label for the next layer of catch blocks. */ | |
1942 | pop_label_entry (&caught_return_label_stack); | |
956d6950 | 1943 | pop_label_entry (&outer_context_label_stack); |
4956d07c MS |
1944 | |
1945 | /* Add the new sequence of catches to the main one for this function. */ | |
1946 | push_to_sequence (catch_clauses); | |
1947 | emit_insns (new_catch_clause); | |
1948 | catch_clauses = get_insns (); | |
1949 | end_sequence (); | |
1950 | ||
1951 | /* Here we fall through into the continuation code. */ | |
1952 | } | |
1953 | ||
e701eb4d JM |
1954 | /* Rethrow from the outer context LABEL. */ |
1955 | ||
1956 | static void | |
1957 | expand_rethrow (label) | |
1958 | rtx label; | |
1959 | { | |
1960 | if (exceptions_via_longjmp) | |
1961 | emit_throw (); | |
1962 | else | |
e6cfb550 AM |
1963 | if (flag_new_exceptions) |
1964 | { | |
1965 | rtx insn, val; | |
1966 | if (label == NULL_RTX) | |
1967 | label = last_rethrow_symbol; | |
1968 | emit_library_call (rethrow_libfunc, 0, VOIDmode, 1, label, Pmode); | |
1969 | SYMBOL_REF_USED (label) = 1; | |
1970 | insn = get_last_insn (); | |
1971 | val = GEN_INT (eh_region_from_symbol (label)); | |
1972 | /* Mark the label/symbol on the call. */ | |
1973 | REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EH_RETHROW, val, | |
1974 | REG_NOTES (insn)); | |
1975 | emit_barrier (); | |
1976 | } | |
1977 | else | |
1978 | emit_jump (label); | |
e701eb4d JM |
1979 | } |
1980 | ||
12670d88 | 1981 | /* End all the pending exception regions on protect_list. The handlers |
27a36778 | 1982 | will be emitted when expand_leftover_cleanups is invoked. */ |
4956d07c MS |
1983 | |
1984 | void | |
1985 | end_protect_partials () | |
1986 | { | |
1987 | while (protect_list) | |
1988 | { | |
1989 | expand_eh_region_end (TREE_VALUE (protect_list)); | |
1990 | protect_list = TREE_CHAIN (protect_list); | |
1991 | } | |
1992 | } | |
27a36778 MS |
1993 | |
1994 | /* Arrange for __terminate to be called if there is an unhandled throw | |
1995 | from within E. */ | |
1996 | ||
1997 | tree | |
1998 | protect_with_terminate (e) | |
1999 | tree e; | |
2000 | { | |
2001 | /* We only need to do this when using setjmp/longjmp EH and the | |
2002 | language requires it, as otherwise we protect all of the handlers | |
2003 | at once, if we need to. */ | |
2004 | if (exceptions_via_longjmp && protect_cleanup_actions_with_terminate) | |
2005 | { | |
2006 | tree handler, result; | |
2007 | ||
2008 | /* All cleanups must be on the function_obstack. */ | |
2009 | push_obstacks_nochange (); | |
2010 | resume_temporary_allocation (); | |
2011 | ||
2012 | handler = make_node (RTL_EXPR); | |
2013 | TREE_TYPE (handler) = void_type_node; | |
2014 | RTL_EXPR_RTL (handler) = const0_rtx; | |
2015 | TREE_SIDE_EFFECTS (handler) = 1; | |
2016 | start_sequence_for_rtl_expr (handler); | |
2017 | ||
2018 | emit_library_call (terminate_libfunc, 0, VOIDmode, 0); | |
2019 | emit_barrier (); | |
2020 | ||
2021 | RTL_EXPR_SEQUENCE (handler) = get_insns (); | |
2022 | end_sequence (); | |
2023 | ||
2024 | result = build (TRY_CATCH_EXPR, TREE_TYPE (e), e, handler); | |
2025 | TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (e); | |
2026 | TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (e); | |
2027 | TREE_READONLY (result) = TREE_READONLY (e); | |
2028 | ||
2029 | pop_obstacks (); | |
2030 | ||
2031 | e = result; | |
2032 | } | |
2033 | ||
2034 | return e; | |
2035 | } | |
4956d07c MS |
2036 | \f |
2037 | /* The exception table that we build that is used for looking up and | |
12670d88 RK |
2038 | dispatching exceptions, the current number of entries, and its |
2039 | maximum size before we have to extend it. | |
2040 | ||
2041 | The number in eh_table is the code label number of the exception | |
27a36778 MS |
2042 | handler for the region. This is added by add_eh_table_entry and |
2043 | used by output_exception_table_entry. */ | |
12670d88 | 2044 | |
9a0d1e1b AM |
2045 | static int *eh_table = NULL; |
2046 | static int eh_table_size = 0; | |
2047 | static int eh_table_max_size = 0; | |
4956d07c MS |
2048 | |
2049 | /* Note the need for an exception table entry for region N. If we | |
12670d88 RK |
2050 | don't need to output an explicit exception table, avoid all of the |
2051 | extra work. | |
2052 | ||
2053 | Called from final_scan_insn when a NOTE_INSN_EH_REGION_BEG is seen. | |
9a0d1e1b | 2054 | (Or NOTE_INSN_EH_REGION_END sometimes) |
12670d88 | 2055 | N is the NOTE_BLOCK_NUMBER of the note, which comes from the code |
abeeec2a | 2056 | label number of the exception handler for the region. */ |
4956d07c MS |
2057 | |
2058 | void | |
2059 | add_eh_table_entry (n) | |
2060 | int n; | |
2061 | { | |
2062 | #ifndef OMIT_EH_TABLE | |
2063 | if (eh_table_size >= eh_table_max_size) | |
2064 | { | |
2065 | if (eh_table) | |
2066 | { | |
2067 | eh_table_max_size += eh_table_max_size>>1; | |
2068 | ||
2069 | if (eh_table_max_size < 0) | |
2070 | abort (); | |
2071 | ||
ca55abae JM |
2072 | eh_table = (int *) xrealloc (eh_table, |
2073 | eh_table_max_size * sizeof (int)); | |
4956d07c MS |
2074 | } |
2075 | else | |
2076 | { | |
2077 | eh_table_max_size = 252; | |
2078 | eh_table = (int *) xmalloc (eh_table_max_size * sizeof (int)); | |
2079 | } | |
2080 | } | |
2081 | eh_table[eh_table_size++] = n; | |
2082 | #endif | |
2083 | } | |
2084 | ||
12670d88 RK |
2085 | /* Return a non-zero value if we need to output an exception table. |
2086 | ||
2087 | On some platforms, we don't have to output a table explicitly. | |
2088 | This routine doesn't mean we don't have one. */ | |
4956d07c MS |
2089 | |
2090 | int | |
2091 | exception_table_p () | |
2092 | { | |
2093 | if (eh_table) | |
2094 | return 1; | |
2095 | ||
2096 | return 0; | |
2097 | } | |
2098 | ||
38e01259 | 2099 | /* Output the entry of the exception table corresponding to the |
12670d88 RK |
2100 | exception region numbered N to file FILE. |
2101 | ||
2102 | N is the code label number corresponding to the handler of the | |
abeeec2a | 2103 | region. */ |
4956d07c MS |
2104 | |
2105 | static void | |
2106 | output_exception_table_entry (file, n) | |
2107 | FILE *file; | |
2108 | int n; | |
2109 | { | |
2110 | char buf[256]; | |
2111 | rtx sym; | |
e6cfb550 AM |
2112 | struct handler_info *handler = get_first_handler (n); |
2113 | int index = find_func_region (n); | |
2114 | rtx rethrow; | |
2115 | ||
2116 | /* form and emit the rethrow label, if needed */ | |
2117 | rethrow = function_eh_regions[index].rethrow_label; | |
2118 | if (rethrow != NULL_RTX && !flag_new_exceptions) | |
2119 | rethrow = NULL_RTX; | |
2120 | if (rethrow != NULL_RTX && handler == NULL) | |
2121 | if (! SYMBOL_REF_USED (rethrow)) | |
2122 | rethrow = NULL_RTX; | |
9a0d1e1b | 2123 | |
4956d07c | 2124 | |
e6cfb550 | 2125 | for ( ; handler != NULL || rethrow != NULL_RTX; handler = handler->next) |
9a0d1e1b | 2126 | { |
e6cfb550 AM |
2127 | /* rethrow label should indicate the LAST entry for a region */ |
2128 | if (rethrow != NULL_RTX && (handler == NULL || handler->next == NULL)) | |
2129 | { | |
2130 | ASM_GENERATE_INTERNAL_LABEL (buf, "LRTH", n); | |
2131 | assemble_label(buf); | |
2132 | rethrow = NULL_RTX; | |
2133 | } | |
2134 | ||
9a0d1e1b AM |
2135 | ASM_GENERATE_INTERNAL_LABEL (buf, "LEHB", n); |
2136 | sym = gen_rtx_SYMBOL_REF (Pmode, buf); | |
2137 | assemble_integer (sym, POINTER_SIZE / BITS_PER_UNIT, 1); | |
4956d07c | 2138 | |
9a0d1e1b AM |
2139 | ASM_GENERATE_INTERNAL_LABEL (buf, "LEHE", n); |
2140 | sym = gen_rtx_SYMBOL_REF (Pmode, buf); | |
2141 | assemble_integer (sym, POINTER_SIZE / BITS_PER_UNIT, 1); | |
2142 | ||
e6cfb550 AM |
2143 | if (handler == NULL) |
2144 | assemble_integer (GEN_INT (0), POINTER_SIZE / BITS_PER_UNIT, 1); | |
2145 | else | |
0177de87 AM |
2146 | { |
2147 | ASM_GENERATE_INTERNAL_LABEL (buf, "L", handler->handler_number); | |
2148 | sym = gen_rtx_SYMBOL_REF (Pmode, buf); | |
2149 | assemble_integer (sym, POINTER_SIZE / BITS_PER_UNIT, 1); | |
2150 | } | |
4956d07c | 2151 | |
a1622f83 AM |
2152 | if (flag_new_exceptions) |
2153 | { | |
e6cfb550 | 2154 | if (handler == NULL || handler->type_info == NULL) |
a1622f83 AM |
2155 | assemble_integer (const0_rtx, POINTER_SIZE / BITS_PER_UNIT, 1); |
2156 | else | |
9c606f69 AM |
2157 | if (handler->type_info == CATCH_ALL_TYPE) |
2158 | assemble_integer (GEN_INT (CATCH_ALL_TYPE), | |
2159 | POINTER_SIZE / BITS_PER_UNIT, 1); | |
2160 | else | |
2161 | output_constant ((tree)(handler->type_info), | |
9a0d1e1b | 2162 | POINTER_SIZE / BITS_PER_UNIT); |
a1622f83 | 2163 | } |
9a0d1e1b | 2164 | putc ('\n', file); /* blank line */ |
bf71cd2e | 2165 | /* We only output the first label under the old scheme */ |
e6cfb550 | 2166 | if (! flag_new_exceptions || handler == NULL) |
bf71cd2e | 2167 | break; |
9a0d1e1b | 2168 | } |
4956d07c MS |
2169 | } |
2170 | ||
abeeec2a | 2171 | /* Output the exception table if we have and need one. */ |
4956d07c | 2172 | |
9a0d1e1b AM |
2173 | static short language_code = 0; |
2174 | static short version_code = 0; | |
2175 | ||
2176 | /* This routine will set the language code for exceptions. */ | |
804a4e13 KG |
2177 | void |
2178 | set_exception_lang_code (code) | |
2179 | int code; | |
9a0d1e1b AM |
2180 | { |
2181 | language_code = code; | |
2182 | } | |
2183 | ||
2184 | /* This routine will set the language version code for exceptions. */ | |
804a4e13 KG |
2185 | void |
2186 | set_exception_version_code (code) | |
2ec10ea9 | 2187 | int code; |
9a0d1e1b AM |
2188 | { |
2189 | version_code = code; | |
2190 | } | |
2191 | ||
9a0d1e1b | 2192 | |
4956d07c MS |
2193 | void |
2194 | output_exception_table () | |
2195 | { | |
2196 | int i; | |
e6cfb550 | 2197 | char buf[256]; |
4956d07c MS |
2198 | extern FILE *asm_out_file; |
2199 | ||
ca55abae | 2200 | if (! doing_eh (0) || ! eh_table) |
4956d07c MS |
2201 | return; |
2202 | ||
2203 | exception_section (); | |
2204 | ||
2205 | /* Beginning marker for table. */ | |
2206 | assemble_align (GET_MODE_ALIGNMENT (ptr_mode)); | |
2207 | assemble_label ("__EXCEPTION_TABLE__"); | |
2208 | ||
a1622f83 AM |
2209 | if (flag_new_exceptions) |
2210 | { | |
2211 | assemble_integer (GEN_INT (NEW_EH_RUNTIME), | |
2212 | POINTER_SIZE / BITS_PER_UNIT, 1); | |
2213 | assemble_integer (GEN_INT (language_code), 2 , 1); | |
2214 | assemble_integer (GEN_INT (version_code), 2 , 1); | |
2215 | ||
2216 | /* Add enough padding to make sure table aligns on a pointer boundry. */ | |
2217 | i = GET_MODE_ALIGNMENT (ptr_mode) / BITS_PER_UNIT - 4; | |
2218 | for ( ; i < 0; i = i + GET_MODE_ALIGNMENT (ptr_mode) / BITS_PER_UNIT) | |
2219 | ; | |
2220 | if (i != 0) | |
2221 | assemble_integer (const0_rtx, i , 1); | |
e6cfb550 AM |
2222 | |
2223 | /* Generate the label for offset calculations on rethrows */ | |
2224 | ASM_GENERATE_INTERNAL_LABEL (buf, "LRTH", 0); | |
2225 | assemble_label(buf); | |
a1622f83 | 2226 | } |
9a0d1e1b | 2227 | |
4956d07c MS |
2228 | for (i = 0; i < eh_table_size; ++i) |
2229 | output_exception_table_entry (asm_out_file, eh_table[i]); | |
2230 | ||
2231 | free (eh_table); | |
9a0d1e1b | 2232 | clear_function_eh_region (); |
4956d07c MS |
2233 | |
2234 | /* Ending marker for table. */ | |
e6cfb550 AM |
2235 | /* Generate the label for end of table. */ |
2236 | ASM_GENERATE_INTERNAL_LABEL (buf, "LRTH", CODE_LABEL_NUMBER (final_rethrow)); | |
2237 | assemble_label(buf); | |
4956d07c | 2238 | assemble_integer (constm1_rtx, POINTER_SIZE / BITS_PER_UNIT, 1); |
a1622f83 | 2239 | |
9a0d1e1b AM |
2240 | /* for binary compatability, the old __throw checked the second |
2241 | position for a -1, so we should output at least 2 -1's */ | |
a1622f83 AM |
2242 | if (! flag_new_exceptions) |
2243 | assemble_integer (constm1_rtx, POINTER_SIZE / BITS_PER_UNIT, 1); | |
2244 | ||
4956d07c MS |
2245 | putc ('\n', asm_out_file); /* blank line */ |
2246 | } | |
4956d07c | 2247 | \f |
154bba13 TT |
2248 | /* Emit code to get EH context. |
2249 | ||
2250 | We have to scan thru the code to find possible EH context registers. | |
2251 | Inlined functions may use it too, and thus we'll have to be able | |
2252 | to change them too. | |
2253 | ||
2254 | This is done only if using exceptions_via_longjmp. */ | |
2255 | ||
2256 | void | |
2257 | emit_eh_context () | |
2258 | { | |
2259 | rtx insn; | |
2260 | rtx ehc = 0; | |
2261 | ||
2262 | if (! doing_eh (0)) | |
2263 | return; | |
2264 | ||
2265 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
2266 | if (GET_CODE (insn) == INSN | |
2267 | && GET_CODE (PATTERN (insn)) == USE) | |
2268 | { | |
2269 | rtx reg = find_reg_note (insn, REG_EH_CONTEXT, 0); | |
2270 | if (reg) | |
2271 | { | |
2272 | rtx insns; | |
2273 | ||
100d81d4 JM |
2274 | start_sequence (); |
2275 | ||
d9c92f32 JM |
2276 | /* If this is the first use insn, emit the call here. This |
2277 | will always be at the top of our function, because if | |
2278 | expand_inline_function notices a REG_EH_CONTEXT note, it | |
2279 | adds a use insn to this function as well. */ | |
154bba13 | 2280 | if (ehc == 0) |
01eb7f9a | 2281 | ehc = call_get_eh_context (); |
154bba13 | 2282 | |
154bba13 TT |
2283 | emit_move_insn (XEXP (reg, 0), ehc); |
2284 | insns = get_insns (); | |
2285 | end_sequence (); | |
2286 | ||
2287 | emit_insns_before (insns, insn); | |
0fc1434b AM |
2288 | |
2289 | /* At -O0, we must make the context register stay alive so | |
2290 | that the stupid.c register allocator doesn't get confused. */ | |
2291 | if (obey_regdecls != 0) | |
2292 | { | |
2293 | insns = gen_rtx_USE (GET_MODE (XEXP (reg,0)), XEXP (reg,0)); | |
2294 | emit_insn_before (insns, get_last_insn ()); | |
2295 | } | |
154bba13 TT |
2296 | } |
2297 | } | |
2298 | } | |
2299 | ||
12670d88 RK |
2300 | /* Scan the current insns and build a list of handler labels. The |
2301 | resulting list is placed in the global variable exception_handler_labels. | |
2302 | ||
2303 | It is called after the last exception handling region is added to | |
2304 | the current function (when the rtl is almost all built for the | |
2305 | current function) and before the jump optimization pass. */ | |
4956d07c MS |
2306 | |
2307 | void | |
2308 | find_exception_handler_labels () | |
2309 | { | |
2310 | rtx insn; | |
4956d07c MS |
2311 | |
2312 | exception_handler_labels = NULL_RTX; | |
2313 | ||
2314 | /* If we aren't doing exception handling, there isn't much to check. */ | |
2315 | if (! doing_eh (0)) | |
2316 | return; | |
2317 | ||
12670d88 RK |
2318 | /* For each start of a region, add its label to the list. */ |
2319 | ||
4956d07c MS |
2320 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
2321 | { | |
9a0d1e1b | 2322 | struct handler_info* ptr; |
4956d07c MS |
2323 | if (GET_CODE (insn) == NOTE |
2324 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) | |
2325 | { | |
9a0d1e1b AM |
2326 | ptr = get_first_handler (NOTE_BLOCK_NUMBER (insn)); |
2327 | for ( ; ptr; ptr = ptr->next) | |
2328 | { | |
2329 | /* make sure label isn't in the list already */ | |
2330 | rtx x; | |
2331 | for (x = exception_handler_labels; x; x = XEXP (x, 1)) | |
2332 | if (XEXP (x, 0) == ptr->handler_label) | |
2333 | break; | |
2334 | if (! x) | |
2335 | exception_handler_labels = gen_rtx_EXPR_LIST (VOIDmode, | |
2336 | ptr->handler_label, exception_handler_labels); | |
2337 | } | |
4956d07c MS |
2338 | } |
2339 | } | |
9a0d1e1b AM |
2340 | } |
2341 | ||
2342 | /* Return a value of 1 if the parameter label number is an exception handler | |
2343 | label. Return 0 otherwise. */ | |
988cea7d | 2344 | |
9a0d1e1b AM |
2345 | int |
2346 | is_exception_handler_label (lab) | |
2347 | int lab; | |
2348 | { | |
2349 | rtx x; | |
2350 | for (x = exception_handler_labels ; x ; x = XEXP (x, 1)) | |
2351 | if (lab == CODE_LABEL_NUMBER (XEXP (x, 0))) | |
2352 | return 1; | |
2353 | return 0; | |
4956d07c MS |
2354 | } |
2355 | ||
12670d88 RK |
2356 | /* Perform sanity checking on the exception_handler_labels list. |
2357 | ||
2358 | Can be called after find_exception_handler_labels is called to | |
2359 | build the list of exception handlers for the current function and | |
2360 | before we finish processing the current function. */ | |
4956d07c MS |
2361 | |
2362 | void | |
2363 | check_exception_handler_labels () | |
2364 | { | |
9a0d1e1b | 2365 | rtx insn, insn2; |
4956d07c MS |
2366 | |
2367 | /* If we aren't doing exception handling, there isn't much to check. */ | |
2368 | if (! doing_eh (0)) | |
2369 | return; | |
2370 | ||
9a0d1e1b AM |
2371 | /* Make sure there is no more than 1 copy of a label */ |
2372 | for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1)) | |
4956d07c | 2373 | { |
9a0d1e1b AM |
2374 | int count = 0; |
2375 | for (insn2 = exception_handler_labels; insn2; insn2 = XEXP (insn2, 1)) | |
2376 | if (XEXP (insn, 0) == XEXP (insn2, 0)) | |
2377 | count++; | |
2378 | if (count != 1) | |
2379 | warning ("Counted %d copies of EH region %d in list.\n", count, | |
2380 | CODE_LABEL_NUMBER (insn)); | |
4956d07c MS |
2381 | } |
2382 | ||
4956d07c MS |
2383 | } |
2384 | \f | |
2385 | /* This group of functions initializes the exception handling data | |
2386 | structures at the start of the compilation, initializes the data | |
12670d88 | 2387 | structures at the start of a function, and saves and restores the |
4956d07c MS |
2388 | exception handling data structures for the start/end of a nested |
2389 | function. */ | |
2390 | ||
2391 | /* Toplevel initialization for EH things. */ | |
2392 | ||
2393 | void | |
2394 | init_eh () | |
2395 | { | |
e6cfb550 AM |
2396 | first_rethrow_symbol = create_rethrow_ref (0); |
2397 | final_rethrow = gen_exception_label (); | |
2398 | last_rethrow_symbol = create_rethrow_ref (CODE_LABEL_NUMBER (final_rethrow)); | |
4956d07c MS |
2399 | } |
2400 | ||
abeeec2a | 2401 | /* Initialize the per-function EH information. */ |
4956d07c MS |
2402 | |
2403 | void | |
2404 | init_eh_for_function () | |
2405 | { | |
2406 | ehstack.top = 0; | |
9a0d1e1b | 2407 | catchstack.top = 0; |
4956d07c MS |
2408 | ehqueue.head = ehqueue.tail = 0; |
2409 | catch_clauses = NULL_RTX; | |
2410 | false_label_stack = 0; | |
2411 | caught_return_label_stack = 0; | |
2412 | protect_list = NULL_TREE; | |
154bba13 | 2413 | current_function_ehc = NULL_RTX; |
71038426 RH |
2414 | eh_return_context = NULL_RTX; |
2415 | eh_return_stack_adjust = NULL_RTX; | |
2416 | eh_return_handler = NULL_RTX; | |
2417 | eh_return_stub_label = NULL_RTX; | |
4956d07c MS |
2418 | } |
2419 | ||
12670d88 RK |
2420 | /* Save some of the per-function EH info into the save area denoted by |
2421 | P. | |
2422 | ||
27a36778 | 2423 | This is currently called from save_stmt_status. */ |
4956d07c MS |
2424 | |
2425 | void | |
2426 | save_eh_status (p) | |
2427 | struct function *p; | |
2428 | { | |
3a88cbd1 JL |
2429 | if (p == NULL) |
2430 | abort (); | |
12670d88 | 2431 | |
4956d07c | 2432 | p->ehstack = ehstack; |
9a0d1e1b | 2433 | p->catchstack = catchstack; |
4956d07c MS |
2434 | p->ehqueue = ehqueue; |
2435 | p->catch_clauses = catch_clauses; | |
2436 | p->false_label_stack = false_label_stack; | |
2437 | p->caught_return_label_stack = caught_return_label_stack; | |
2438 | p->protect_list = protect_list; | |
154bba13 | 2439 | p->ehc = current_function_ehc; |
4956d07c | 2440 | |
6e1f1f93 | 2441 | init_eh_for_function (); |
4956d07c MS |
2442 | } |
2443 | ||
12670d88 RK |
2444 | /* Restore the per-function EH info saved into the area denoted by P. |
2445 | ||
abeeec2a | 2446 | This is currently called from restore_stmt_status. */ |
4956d07c MS |
2447 | |
2448 | void | |
2449 | restore_eh_status (p) | |
2450 | struct function *p; | |
2451 | { | |
3a88cbd1 JL |
2452 | if (p == NULL) |
2453 | abort (); | |
12670d88 | 2454 | |
4956d07c MS |
2455 | protect_list = p->protect_list; |
2456 | caught_return_label_stack = p->caught_return_label_stack; | |
2457 | false_label_stack = p->false_label_stack; | |
2458 | catch_clauses = p->catch_clauses; | |
2459 | ehqueue = p->ehqueue; | |
2460 | ehstack = p->ehstack; | |
9a0d1e1b | 2461 | catchstack = p->catchstack; |
154bba13 | 2462 | current_function_ehc = p->ehc; |
4956d07c MS |
2463 | } |
2464 | \f | |
2465 | /* This section is for the exception handling specific optimization | |
2466 | pass. First are the internal routines, and then the main | |
2467 | optimization pass. */ | |
2468 | ||
2469 | /* Determine if the given INSN can throw an exception. */ | |
2470 | ||
2471 | static int | |
2472 | can_throw (insn) | |
2473 | rtx insn; | |
2474 | { | |
abeeec2a | 2475 | /* Calls can always potentially throw exceptions. */ |
4956d07c MS |
2476 | if (GET_CODE (insn) == CALL_INSN) |
2477 | return 1; | |
2478 | ||
27a36778 MS |
2479 | if (asynchronous_exceptions) |
2480 | { | |
2481 | /* If we wanted asynchronous exceptions, then everything but NOTEs | |
2482 | and CODE_LABELs could throw. */ | |
2483 | if (GET_CODE (insn) != NOTE && GET_CODE (insn) != CODE_LABEL) | |
2484 | return 1; | |
2485 | } | |
4956d07c MS |
2486 | |
2487 | return 0; | |
2488 | } | |
2489 | ||
12670d88 RK |
2490 | /* Scan a exception region looking for the matching end and then |
2491 | remove it if possible. INSN is the start of the region, N is the | |
2492 | region number, and DELETE_OUTER is to note if anything in this | |
2493 | region can throw. | |
2494 | ||
2495 | Regions are removed if they cannot possibly catch an exception. | |
27a36778 | 2496 | This is determined by invoking can_throw on each insn within the |
12670d88 RK |
2497 | region; if can_throw returns true for any of the instructions, the |
2498 | region can catch an exception, since there is an insn within the | |
2499 | region that is capable of throwing an exception. | |
2500 | ||
2501 | Returns the NOTE_INSN_EH_REGION_END corresponding to this region, or | |
27a36778 | 2502 | calls abort if it can't find one. |
12670d88 RK |
2503 | |
2504 | Can abort if INSN is not a NOTE_INSN_EH_REGION_BEGIN, or if N doesn't | |
abeeec2a | 2505 | correspond to the region number, or if DELETE_OUTER is NULL. */ |
4956d07c MS |
2506 | |
2507 | static rtx | |
2508 | scan_region (insn, n, delete_outer) | |
2509 | rtx insn; | |
2510 | int n; | |
2511 | int *delete_outer; | |
2512 | { | |
2513 | rtx start = insn; | |
2514 | ||
2515 | /* Assume we can delete the region. */ | |
2516 | int delete = 1; | |
2517 | ||
e6cfb550 AM |
2518 | int r = find_func_region (n); |
2519 | /* Can't delete something which is rethrown to. */ | |
2520 | if (SYMBOL_REF_USED((function_eh_regions[r].rethrow_label))) | |
2521 | delete = 0; | |
2522 | ||
3a88cbd1 JL |
2523 | if (insn == NULL_RTX |
2524 | || GET_CODE (insn) != NOTE | |
2525 | || NOTE_LINE_NUMBER (insn) != NOTE_INSN_EH_REGION_BEG | |
2526 | || NOTE_BLOCK_NUMBER (insn) != n | |
2527 | || delete_outer == NULL) | |
2528 | abort (); | |
12670d88 | 2529 | |
4956d07c MS |
2530 | insn = NEXT_INSN (insn); |
2531 | ||
2532 | /* Look for the matching end. */ | |
2533 | while (! (GET_CODE (insn) == NOTE | |
2534 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)) | |
2535 | { | |
2536 | /* If anything can throw, we can't remove the region. */ | |
2537 | if (delete && can_throw (insn)) | |
2538 | { | |
2539 | delete = 0; | |
2540 | } | |
2541 | ||
2542 | /* Watch out for and handle nested regions. */ | |
2543 | if (GET_CODE (insn) == NOTE | |
2544 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) | |
2545 | { | |
2546 | insn = scan_region (insn, NOTE_BLOCK_NUMBER (insn), &delete); | |
2547 | } | |
2548 | ||
2549 | insn = NEXT_INSN (insn); | |
2550 | } | |
2551 | ||
2552 | /* The _BEG/_END NOTEs must match and nest. */ | |
2553 | if (NOTE_BLOCK_NUMBER (insn) != n) | |
2554 | abort (); | |
2555 | ||
12670d88 | 2556 | /* If anything in this exception region can throw, we can throw. */ |
4956d07c MS |
2557 | if (! delete) |
2558 | *delete_outer = 0; | |
2559 | else | |
2560 | { | |
2561 | /* Delete the start and end of the region. */ | |
2562 | delete_insn (start); | |
2563 | delete_insn (insn); | |
2564 | ||
9a0d1e1b AM |
2565 | /* We no longer removed labels here, since flow will now remove any |
2566 | handler which cannot be called any more. */ | |
2567 | ||
2568 | #if 0 | |
4956d07c MS |
2569 | /* Only do this part if we have built the exception handler |
2570 | labels. */ | |
2571 | if (exception_handler_labels) | |
2572 | { | |
2573 | rtx x, *prev = &exception_handler_labels; | |
2574 | ||
2575 | /* Find it in the list of handlers. */ | |
2576 | for (x = exception_handler_labels; x; x = XEXP (x, 1)) | |
2577 | { | |
2578 | rtx label = XEXP (x, 0); | |
2579 | if (CODE_LABEL_NUMBER (label) == n) | |
2580 | { | |
2581 | /* If we are the last reference to the handler, | |
2582 | delete it. */ | |
2583 | if (--LABEL_NUSES (label) == 0) | |
2584 | delete_insn (label); | |
2585 | ||
2586 | if (optimize) | |
2587 | { | |
2588 | /* Remove it from the list of exception handler | |
2589 | labels, if we are optimizing. If we are not, then | |
2590 | leave it in the list, as we are not really going to | |
2591 | remove the region. */ | |
2592 | *prev = XEXP (x, 1); | |
2593 | XEXP (x, 1) = 0; | |
2594 | XEXP (x, 0) = 0; | |
2595 | } | |
2596 | ||
2597 | break; | |
2598 | } | |
2599 | prev = &XEXP (x, 1); | |
2600 | } | |
2601 | } | |
9a0d1e1b | 2602 | #endif |
4956d07c MS |
2603 | } |
2604 | return insn; | |
2605 | } | |
2606 | ||
2607 | /* Perform various interesting optimizations for exception handling | |
2608 | code. | |
2609 | ||
12670d88 RK |
2610 | We look for empty exception regions and make them go (away). The |
2611 | jump optimization code will remove the handler if nothing else uses | |
abeeec2a | 2612 | it. */ |
4956d07c MS |
2613 | |
2614 | void | |
2615 | exception_optimize () | |
2616 | { | |
381127e8 | 2617 | rtx insn; |
4956d07c MS |
2618 | int n; |
2619 | ||
12670d88 | 2620 | /* Remove empty regions. */ |
4956d07c MS |
2621 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
2622 | { | |
2623 | if (GET_CODE (insn) == NOTE | |
2624 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) | |
2625 | { | |
27a36778 | 2626 | /* Since scan_region will return the NOTE_INSN_EH_REGION_END |
12670d88 RK |
2627 | insn, we will indirectly skip through all the insns |
2628 | inbetween. We are also guaranteed that the value of insn | |
27a36778 | 2629 | returned will be valid, as otherwise scan_region won't |
abeeec2a | 2630 | return. */ |
4956d07c MS |
2631 | insn = scan_region (insn, NOTE_BLOCK_NUMBER (insn), &n); |
2632 | } | |
2633 | } | |
2634 | } | |
ca55abae JM |
2635 | \f |
2636 | /* Various hooks for the DWARF 2 __throw routine. */ | |
2637 | ||
2638 | /* Do any necessary initialization to access arbitrary stack frames. | |
2639 | On the SPARC, this means flushing the register windows. */ | |
2640 | ||
2641 | void | |
2642 | expand_builtin_unwind_init () | |
2643 | { | |
2644 | /* Set this so all the registers get saved in our frame; we need to be | |
2645 | able to copy the saved values for any registers from frames we unwind. */ | |
2646 | current_function_has_nonlocal_label = 1; | |
2647 | ||
2648 | #ifdef SETUP_FRAME_ADDRESSES | |
2649 | SETUP_FRAME_ADDRESSES (); | |
2650 | #endif | |
2651 | } | |
2652 | ||
2653 | /* Given a value extracted from the return address register or stack slot, | |
2654 | return the actual address encoded in that value. */ | |
2655 | ||
2656 | rtx | |
2657 | expand_builtin_extract_return_addr (addr_tree) | |
2658 | tree addr_tree; | |
2659 | { | |
2660 | rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, 0); | |
2661 | return eh_outer_context (addr); | |
2662 | } | |
2663 | ||
2664 | /* Given an actual address in addr_tree, do any necessary encoding | |
2665 | and return the value to be stored in the return address register or | |
2666 | stack slot so the epilogue will return to that address. */ | |
2667 | ||
2668 | rtx | |
2669 | expand_builtin_frob_return_addr (addr_tree) | |
2670 | tree addr_tree; | |
2671 | { | |
2672 | rtx addr = expand_expr (addr_tree, NULL_RTX, Pmode, 0); | |
2673 | #ifdef RETURN_ADDR_OFFSET | |
2674 | addr = plus_constant (addr, -RETURN_ADDR_OFFSET); | |
2675 | #endif | |
2676 | return addr; | |
2677 | } | |
2678 | ||
71038426 RH |
2679 | /* Choose three registers for communication between the main body of |
2680 | __throw and the epilogue (or eh stub) and the exception handler. | |
2681 | We must do this with hard registers because the epilogue itself | |
2682 | will be generated after reload, at which point we may not reference | |
2683 | pseudos at all. | |
ca55abae | 2684 | |
71038426 RH |
2685 | The first passes the exception context to the handler. For this |
2686 | we use the return value register for a void*. | |
ca55abae | 2687 | |
71038426 RH |
2688 | The second holds the stack pointer value to be restored. For |
2689 | this we use the static chain register if it exists and is different | |
2690 | from the previous, otherwise some arbitrary call-clobbered register. | |
ca55abae | 2691 | |
71038426 RH |
2692 | The third holds the address of the handler itself. Here we use |
2693 | some arbitrary call-clobbered register. */ | |
ca55abae JM |
2694 | |
2695 | static void | |
71038426 RH |
2696 | eh_regs (pcontext, psp, pra, outgoing) |
2697 | rtx *pcontext, *psp, *pra; | |
ca55abae JM |
2698 | int outgoing; |
2699 | { | |
71038426 RH |
2700 | rtx rcontext, rsp, rra; |
2701 | int i; | |
ca55abae JM |
2702 | |
2703 | #ifdef FUNCTION_OUTGOING_VALUE | |
2704 | if (outgoing) | |
71038426 RH |
2705 | rcontext = FUNCTION_OUTGOING_VALUE (build_pointer_type (void_type_node), |
2706 | current_function_decl); | |
ca55abae JM |
2707 | else |
2708 | #endif | |
71038426 RH |
2709 | rcontext = FUNCTION_VALUE (build_pointer_type (void_type_node), |
2710 | current_function_decl); | |
ca55abae JM |
2711 | |
2712 | #ifdef STATIC_CHAIN_REGNUM | |
2713 | if (outgoing) | |
71038426 | 2714 | rsp = static_chain_incoming_rtx; |
ca55abae | 2715 | else |
71038426 RH |
2716 | rsp = static_chain_rtx; |
2717 | if (REGNO (rsp) == REGNO (rcontext)) | |
ca55abae | 2718 | #endif /* STATIC_CHAIN_REGNUM */ |
71038426 | 2719 | rsp = NULL_RTX; |
ca55abae | 2720 | |
71038426 | 2721 | if (rsp == NULL_RTX) |
ca55abae | 2722 | { |
ca55abae | 2723 | for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) |
71038426 RH |
2724 | if (call_used_regs[i] && ! fixed_regs[i] && i != REGNO (rcontext)) |
2725 | break; | |
2726 | if (i == FIRST_PSEUDO_REGISTER) | |
2727 | abort(); | |
ca55abae | 2728 | |
71038426 | 2729 | rsp = gen_rtx_REG (Pmode, i); |
ca55abae JM |
2730 | } |
2731 | ||
71038426 RH |
2732 | for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) |
2733 | if (call_used_regs[i] && ! fixed_regs[i] | |
2734 | && i != REGNO (rcontext) && i != REGNO (rsp)) | |
2735 | break; | |
2736 | if (i == FIRST_PSEUDO_REGISTER) | |
2737 | abort(); | |
2738 | ||
2739 | rra = gen_rtx_REG (Pmode, i); | |
ca55abae | 2740 | |
71038426 RH |
2741 | *pcontext = rcontext; |
2742 | *psp = rsp; | |
2743 | *pra = rra; | |
2744 | } | |
9a0d1e1b AM |
2745 | |
2746 | /* Retrieve the register which contains the pointer to the eh_context | |
2747 | structure set the __throw. */ | |
2748 | ||
2749 | rtx | |
2750 | get_reg_for_handler () | |
2751 | { | |
2752 | rtx reg1; | |
2753 | reg1 = FUNCTION_VALUE (build_pointer_type (void_type_node), | |
2754 | current_function_decl); | |
2755 | return reg1; | |
2756 | } | |
2757 | ||
71038426 RH |
2758 | /* Set up the epilogue with the magic bits we'll need to return to the |
2759 | exception handler. */ | |
9a0d1e1b | 2760 | |
71038426 RH |
2761 | void |
2762 | expand_builtin_eh_return (context, stack, handler) | |
2763 | tree context, stack, handler; | |
a1622f83 | 2764 | { |
71038426 RH |
2765 | if (eh_return_context) |
2766 | error("Duplicate call to __builtin_eh_return"); | |
a1622f83 | 2767 | |
71038426 RH |
2768 | eh_return_context |
2769 | = copy_to_reg (expand_expr (context, NULL_RTX, VOIDmode, 0)); | |
2770 | eh_return_stack_adjust | |
2771 | = copy_to_reg (expand_expr (stack, NULL_RTX, VOIDmode, 0)); | |
2772 | eh_return_handler | |
2773 | = copy_to_reg (expand_expr (handler, NULL_RTX, VOIDmode, 0)); | |
a1622f83 AM |
2774 | } |
2775 | ||
71038426 RH |
2776 | void |
2777 | expand_eh_return () | |
ca55abae | 2778 | { |
71038426 RH |
2779 | rtx reg1, reg2, reg3; |
2780 | rtx stub_start, after_stub; | |
2781 | rtx ra, tmp; | |
ca55abae | 2782 | |
71038426 RH |
2783 | if (!eh_return_context) |
2784 | return; | |
ca55abae | 2785 | |
71038426 RH |
2786 | eh_regs (®1, ®2, ®3, 1); |
2787 | emit_move_insn (reg1, eh_return_context); | |
2788 | emit_move_insn (reg2, eh_return_stack_adjust); | |
2789 | emit_move_insn (reg3, eh_return_handler); | |
9a0d1e1b | 2790 | |
71038426 | 2791 | /* Talk directly to the target's epilogue code when possible. */ |
9a0d1e1b | 2792 | |
71038426 RH |
2793 | #ifdef HAVE_eh_epilogue |
2794 | if (HAVE_eh_epilogue) | |
2795 | { | |
2796 | emit_insn (gen_eh_epilogue (reg1, reg2, reg3)); | |
2797 | return; | |
2798 | } | |
2799 | #endif | |
9a0d1e1b | 2800 | |
71038426 | 2801 | /* Otherwise, use the same stub technique we had before. */ |
ca55abae | 2802 | |
71038426 RH |
2803 | eh_return_stub_label = stub_start = gen_label_rtx (); |
2804 | after_stub = gen_label_rtx (); | |
ca55abae | 2805 | |
71038426 | 2806 | /* Set the return address to the stub label. */ |
ca55abae | 2807 | |
71038426 RH |
2808 | ra = expand_builtin_return_addr (BUILT_IN_RETURN_ADDRESS, |
2809 | 0, hard_frame_pointer_rtx); | |
2810 | if (GET_CODE (ra) == REG && REGNO (ra) >= FIRST_PSEUDO_REGISTER) | |
2811 | abort(); | |
ca55abae | 2812 | |
71038426 RH |
2813 | tmp = memory_address (Pmode, gen_rtx_LABEL_REF (Pmode, stub_start)); |
2814 | #ifdef RETURN_ADDR_OFFSET | |
2815 | tmp = plus_constant (tmp, -RETURN_ADDR_OFFSET); | |
2816 | #endif | |
2a55b8e8 JW |
2817 | tmp = force_operand (tmp, ra); |
2818 | if (tmp != ra) | |
2819 | emit_move_insn (ra, tmp); | |
ca55abae | 2820 | |
71038426 | 2821 | /* Indicate that the registers are in fact used. */ |
38a448ca RH |
2822 | emit_insn (gen_rtx_USE (VOIDmode, reg1)); |
2823 | emit_insn (gen_rtx_USE (VOIDmode, reg2)); | |
71038426 RH |
2824 | emit_insn (gen_rtx_USE (VOIDmode, reg3)); |
2825 | if (GET_CODE (ra) == REG) | |
2826 | emit_insn (gen_rtx_USE (VOIDmode, ra)); | |
77d33a84 | 2827 | |
71038426 RH |
2828 | /* Generate the stub. */ |
2829 | ||
2830 | emit_jump (after_stub); | |
2831 | emit_label (stub_start); | |
2832 | ||
2833 | eh_regs (®1, ®2, ®3, 0); | |
2834 | adjust_stack (reg2); | |
2835 | emit_indirect_jump (reg3); | |
2836 | ||
2837 | emit_label (after_stub); | |
2838 | } | |
77d33a84 AM |
2839 | \f |
2840 | ||
2841 | /* This contains the code required to verify whether arbitrary instructions | |
2842 | are in the same exception region. */ | |
2843 | ||
2844 | static int *insn_eh_region = (int *)0; | |
2845 | static int maximum_uid; | |
2846 | ||
242c13b0 JL |
2847 | static void |
2848 | set_insn_eh_region (first, region_num) | |
77d33a84 AM |
2849 | rtx *first; |
2850 | int region_num; | |
2851 | { | |
2852 | rtx insn; | |
2853 | int rnum; | |
2854 | ||
2855 | for (insn = *first; insn; insn = NEXT_INSN (insn)) | |
2856 | { | |
2857 | if ((GET_CODE (insn) == NOTE) && | |
2858 | (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)) | |
2859 | { | |
2860 | rnum = NOTE_BLOCK_NUMBER (insn); | |
2861 | insn_eh_region[INSN_UID (insn)] = rnum; | |
2862 | insn = NEXT_INSN (insn); | |
2863 | set_insn_eh_region (&insn, rnum); | |
2864 | /* Upon return, insn points to the EH_REGION_END of nested region */ | |
2865 | continue; | |
2866 | } | |
2867 | insn_eh_region[INSN_UID (insn)] = region_num; | |
2868 | if ((GET_CODE (insn) == NOTE) && | |
2869 | (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)) | |
2870 | break; | |
2871 | } | |
2872 | *first = insn; | |
2873 | } | |
2874 | ||
2875 | /* Free the insn table, an make sure it cannot be used again. */ | |
2876 | ||
9a0d1e1b AM |
2877 | void |
2878 | free_insn_eh_region () | |
77d33a84 AM |
2879 | { |
2880 | if (!doing_eh (0)) | |
2881 | return; | |
2882 | ||
2883 | if (insn_eh_region) | |
2884 | { | |
2885 | free (insn_eh_region); | |
2886 | insn_eh_region = (int *)0; | |
2887 | } | |
2888 | } | |
2889 | ||
2890 | /* Initialize the table. max_uid must be calculated and handed into | |
2891 | this routine. If it is unavailable, passing a value of 0 will | |
2892 | cause this routine to calculate it as well. */ | |
2893 | ||
9a0d1e1b AM |
2894 | void |
2895 | init_insn_eh_region (first, max_uid) | |
77d33a84 AM |
2896 | rtx first; |
2897 | int max_uid; | |
2898 | { | |
2899 | rtx insn; | |
2900 | ||
2901 | if (!doing_eh (0)) | |
2902 | return; | |
2903 | ||
2904 | if (insn_eh_region) | |
2905 | free_insn_eh_region(); | |
2906 | ||
2907 | if (max_uid == 0) | |
2908 | for (insn = first; insn; insn = NEXT_INSN (insn)) | |
2909 | if (INSN_UID (insn) > max_uid) /* find largest UID */ | |
2910 | max_uid = INSN_UID (insn); | |
2911 | ||
2912 | maximum_uid = max_uid; | |
2913 | insn_eh_region = (int *) malloc ((max_uid + 1) * sizeof (int)); | |
2914 | insn = first; | |
2915 | set_insn_eh_region (&insn, 0); | |
2916 | } | |
2917 | ||
2918 | ||
2919 | /* Check whether 2 instructions are within the same region. */ | |
2920 | ||
9a0d1e1b AM |
2921 | int |
2922 | in_same_eh_region (insn1, insn2) | |
2923 | rtx insn1, insn2; | |
77d33a84 AM |
2924 | { |
2925 | int ret, uid1, uid2; | |
2926 | ||
2927 | /* If no exceptions, instructions are always in same region. */ | |
2928 | if (!doing_eh (0)) | |
2929 | return 1; | |
2930 | ||
2931 | /* If the table isn't allocated, assume the worst. */ | |
2932 | if (!insn_eh_region) | |
2933 | return 0; | |
2934 | ||
2935 | uid1 = INSN_UID (insn1); | |
2936 | uid2 = INSN_UID (insn2); | |
2937 | ||
2938 | /* if instructions have been allocated beyond the end, either | |
2939 | the table is out of date, or this is a late addition, or | |
2940 | something... Assume the worst. */ | |
2941 | if (uid1 > maximum_uid || uid2 > maximum_uid) | |
2942 | return 0; | |
2943 | ||
2944 | ret = (insn_eh_region[uid1] == insn_eh_region[uid2]); | |
2945 | return ret; | |
2946 | } | |
2947 |