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b4c522fa | 1 | // GNU D Compiler exception personality routines. |
99dee823 | 2 | // Copyright (C) 2011-2021 Free Software Foundation, Inc. |
b4c522fa IB |
3 | |
4 | // GCC is free software; you can redistribute it and/or modify it under | |
5 | // the terms of the GNU General Public License as published by the Free | |
6 | // Software Foundation; either version 3, or (at your option) any later | |
7 | // version. | |
8 | ||
9 | // GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
10 | // WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 | // for more details. | |
13 | ||
14 | // Under Section 7 of GPL version 3, you are granted additional | |
15 | // permissions described in the GCC Runtime Library Exception, version | |
16 | // 3.1, as published by the Free Software Foundation. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License and | |
19 | // a copy of the GCC Runtime Library Exception along with this program; | |
20 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
21 | // <http://www.gnu.org/licenses/>. | |
22 | ||
23 | // This code is based on the libstdc++ exception handling routines. | |
24 | ||
25 | module gcc.deh; | |
26 | ||
27 | import gcc.unwind; | |
28 | import gcc.unwind.pe; | |
29 | import gcc.builtins; | |
30 | import gcc.config; | |
8e84a142 | 31 | import gcc.attributes; |
b4c522fa IB |
32 | |
33 | extern(C) | |
34 | { | |
35 | int _d_isbaseof(ClassInfo, ClassInfo); | |
36 | void _d_createTrace(Object, void*); | |
b4c522fa IB |
37 | } |
38 | ||
39 | /** | |
40 | * Declare all known and handled exception classes. | |
41 | * D exceptions -- "GNUCD\0\0\0". | |
42 | * C++ exceptions -- "GNUCC++\0" | |
43 | * C++ dependent exceptions -- "GNUCC++\x01" | |
44 | */ | |
45 | static if (GNU_ARM_EABI_Unwinder) | |
46 | { | |
47 | enum _Unwind_Exception_Class gdcExceptionClass = "GNUCD\0\0\0"; | |
48 | enum _Unwind_Exception_Class gxxExceptionClass = "GNUCC++\0"; | |
49 | enum _Unwind_Exception_Class gxxDependentExceptionClass = "GNUCC++\x01"; | |
50 | } | |
51 | else | |
52 | { | |
53 | enum _Unwind_Exception_Class gdcExceptionClass = | |
54 | (cast(_Unwind_Exception_Class)'G' << 56) | | |
55 | (cast(_Unwind_Exception_Class)'N' << 48) | | |
56 | (cast(_Unwind_Exception_Class)'U' << 40) | | |
57 | (cast(_Unwind_Exception_Class)'C' << 32) | | |
58 | (cast(_Unwind_Exception_Class)'D' << 24); | |
59 | ||
60 | enum _Unwind_Exception_Class gxxExceptionClass = | |
61 | (cast(_Unwind_Exception_Class)'G' << 56) | | |
62 | (cast(_Unwind_Exception_Class)'N' << 48) | | |
63 | (cast(_Unwind_Exception_Class)'U' << 40) | | |
64 | (cast(_Unwind_Exception_Class)'C' << 32) | | |
65 | (cast(_Unwind_Exception_Class)'C' << 24) | | |
66 | (cast(_Unwind_Exception_Class)'+' << 16) | | |
67 | (cast(_Unwind_Exception_Class)'+' << 8) | | |
68 | (cast(_Unwind_Exception_Class)0 << 0); | |
69 | ||
70 | enum _Unwind_Exception_Class gxxDependentExceptionClass = | |
71 | gxxExceptionClass + 1; | |
72 | } | |
73 | ||
74 | /** | |
75 | * Checks for GDC exception class. | |
76 | */ | |
77 | bool isGdcExceptionClass(_Unwind_Exception_Class c) @nogc | |
78 | { | |
79 | static if (GNU_ARM_EABI_Unwinder) | |
80 | { | |
81 | return c[0] == gdcExceptionClass[0] | |
82 | && c[1] == gdcExceptionClass[1] | |
83 | && c[2] == gdcExceptionClass[2] | |
84 | && c[3] == gdcExceptionClass[3] | |
85 | && c[4] == gdcExceptionClass[4] | |
86 | && c[5] == gdcExceptionClass[5] | |
87 | && c[6] == gdcExceptionClass[6] | |
88 | && c[7] == gdcExceptionClass[7]; | |
89 | } | |
90 | else | |
91 | { | |
92 | return c == gdcExceptionClass; | |
93 | } | |
94 | } | |
95 | ||
96 | /** | |
97 | * Checks for any C++ exception class. | |
98 | */ | |
99 | bool isGxxExceptionClass(_Unwind_Exception_Class c) @nogc | |
100 | { | |
101 | static if (GNU_ARM_EABI_Unwinder) | |
102 | { | |
103 | return c[0] == gxxExceptionClass[0] | |
104 | && c[1] == gxxExceptionClass[1] | |
105 | && c[2] == gxxExceptionClass[2] | |
106 | && c[3] == gxxExceptionClass[3] | |
107 | && c[4] == gxxExceptionClass[4] | |
108 | && c[5] == gxxExceptionClass[5] | |
109 | && c[6] == gxxExceptionClass[6] | |
110 | && (c[7] == gxxExceptionClass[7] | |
111 | || c[7] == gxxDependentExceptionClass[7]); | |
112 | } | |
113 | else | |
114 | { | |
115 | return c == gxxExceptionClass | |
116 | || c == gxxDependentExceptionClass; | |
117 | } | |
118 | } | |
119 | ||
120 | /** | |
121 | * Checks for primary or dependent, but not that it is a C++ exception. | |
122 | */ | |
123 | bool isDependentException(_Unwind_Exception_Class c) @nogc | |
124 | { | |
125 | static if (GNU_ARM_EABI_Unwinder) | |
126 | return (c[7] == '\x01'); | |
127 | else | |
128 | return (c & 1); | |
129 | } | |
130 | ||
131 | /** | |
132 | * A D exception object consists of a header, which is a wrapper | |
133 | * around an unwind object header with additional D specific | |
134 | * information, prefixed by the exception object itself. | |
135 | */ | |
136 | struct ExceptionHeader | |
137 | { | |
138 | // Because of a lack of __aligned__ style attribute, our object | |
139 | // and the unwind object are the first two fields. | |
140 | static if (Throwable.alignof < _Unwind_Exception.alignof) | |
141 | ubyte[_Unwind_Exception.alignof - Throwable.alignof] pad; | |
142 | ||
143 | // The object being thrown. The compiled code expects this to | |
144 | // be immediately before the generic exception header. | |
145 | Throwable object; | |
146 | ||
147 | // The generic exception header. | |
148 | _Unwind_Exception unwindHeader; | |
149 | ||
150 | static assert(unwindHeader.offsetof - object.offsetof == object.sizeof); | |
151 | ||
152 | // Cache handler details between Phase 1 and Phase 2. | |
153 | static if (GNU_ARM_EABI_Unwinder) | |
154 | { | |
155 | // Nothing here yet. | |
156 | } | |
157 | else | |
158 | { | |
159 | // Which catch was found. | |
160 | int handler; | |
161 | ||
162 | // Language Specific Data Area for function enclosing the handler. | |
163 | const(ubyte)* languageSpecificData; | |
164 | ||
165 | // Pointer to catch code. | |
166 | _Unwind_Ptr landingPad; | |
167 | ||
168 | // Canonical Frame Address (CFA) for the enclosing handler. | |
169 | _Unwind_Word canonicalFrameAddress; | |
170 | } | |
171 | ||
172 | // Stack other thrown exceptions in current thread through here. | |
173 | ExceptionHeader* next; | |
174 | ||
175 | // Thread local stack of chained exceptions. | |
176 | static ExceptionHeader* stack; | |
177 | ||
178 | // Pre-allocate storage for 1 instance per thread. | |
179 | // Use calloc/free for multiple exceptions in flight. | |
180 | static ExceptionHeader ehstorage; | |
181 | ||
182 | /** | |
183 | * Allocate and initialize an ExceptionHeader. | |
184 | */ | |
185 | static ExceptionHeader* create(Throwable o) @nogc | |
186 | { | |
187 | auto eh = &ehstorage; | |
188 | ||
189 | // Check exception object in use. | |
190 | if (eh.object) | |
191 | { | |
192 | eh = cast(ExceptionHeader*) __builtin_calloc(ExceptionHeader.sizeof, 1); | |
193 | // Out of memory while throwing - not much else can be done. | |
194 | if (!eh) | |
195 | terminate("out of memory", __LINE__); | |
196 | } | |
197 | eh.object = o; | |
198 | ||
199 | eh.unwindHeader.exception_class = gdcExceptionClass; | |
200 | ||
201 | return eh; | |
202 | } | |
203 | ||
204 | /** | |
205 | * Free ExceptionHeader that was created by create(). | |
206 | */ | |
207 | static void free(ExceptionHeader* eh) @nogc | |
208 | { | |
209 | *eh = ExceptionHeader.init; | |
210 | if (eh != &ehstorage) | |
211 | __builtin_free(eh); | |
212 | } | |
213 | ||
214 | /** | |
215 | * Push this onto stack of chained exceptions. | |
216 | */ | |
217 | void push() @nogc | |
218 | { | |
219 | next = stack; | |
220 | stack = &this; | |
221 | } | |
222 | ||
223 | /** | |
224 | * Pop and return top of chained exception stack. | |
225 | */ | |
226 | static ExceptionHeader* pop() @nogc | |
227 | { | |
228 | auto eh = stack; | |
229 | stack = eh.next; | |
230 | return eh; | |
231 | } | |
232 | ||
233 | /** | |
234 | * Save stage1 handler information in the exception object. | |
235 | */ | |
236 | static void save(_Unwind_Exception* unwindHeader, | |
237 | _Unwind_Word cfa, int handler, | |
238 | const(ubyte)* lsda, _Unwind_Ptr landingPad) @nogc | |
239 | { | |
240 | static if (GNU_ARM_EABI_Unwinder) | |
241 | { | |
242 | unwindHeader.barrier_cache.sp = cfa; | |
243 | unwindHeader.barrier_cache.bitpattern[1] = cast(_uw)handler; | |
244 | unwindHeader.barrier_cache.bitpattern[2] = cast(_uw)lsda; | |
245 | unwindHeader.barrier_cache.bitpattern[3] = cast(_uw)landingPad; | |
246 | } | |
247 | else | |
248 | { | |
249 | ExceptionHeader* eh = toExceptionHeader(unwindHeader); | |
250 | eh.canonicalFrameAddress = cfa; | |
251 | eh.handler = handler; | |
252 | eh.languageSpecificData = lsda; | |
253 | eh.landingPad = landingPad; | |
254 | } | |
255 | } | |
256 | ||
257 | /** | |
258 | * Restore the catch handler data saved during phase1. | |
259 | */ | |
260 | static void restore(_Unwind_Exception* unwindHeader, out int handler, | |
261 | out const(ubyte)* lsda, out _Unwind_Ptr landingPad, | |
262 | out _Unwind_Word cfa) @nogc | |
263 | { | |
264 | static if (GNU_ARM_EABI_Unwinder) | |
265 | { | |
266 | cfa = unwindHeader.barrier_cache.sp; | |
267 | handler = cast(int)unwindHeader.barrier_cache.bitpattern[1]; | |
268 | lsda = cast(ubyte*)unwindHeader.barrier_cache.bitpattern[2]; | |
269 | landingPad = cast(_Unwind_Ptr)unwindHeader.barrier_cache.bitpattern[3]; | |
270 | } | |
271 | else | |
272 | { | |
273 | ExceptionHeader* eh = toExceptionHeader(unwindHeader); | |
274 | cfa = eh.canonicalFrameAddress; | |
275 | handler = eh.handler; | |
276 | lsda = eh.languageSpecificData; | |
277 | landingPad = cast(_Unwind_Ptr)eh.landingPad; | |
278 | } | |
279 | } | |
280 | ||
281 | /** | |
282 | * Look at the chain of inflight exceptions and pick the class type that'll | |
283 | * be looked for in catch clauses. | |
284 | */ | |
285 | static ClassInfo getClassInfo(_Unwind_Exception* unwindHeader) @nogc | |
286 | { | |
287 | ExceptionHeader* eh = toExceptionHeader(unwindHeader); | |
288 | // The first thrown Exception at the top of the stack takes precedence | |
289 | // over others that are inflight, unless an Error was thrown, in which | |
290 | // case, we search for error handlers instead. | |
291 | Throwable ehobject = eh.object; | |
292 | for (ExceptionHeader* ehn = eh.next; ehn; ehn = ehn.next) | |
293 | { | |
294 | Error e = cast(Error)ehobject; | |
295 | if (e is null || (cast(Error)ehn.object) !is null) | |
296 | ehobject = ehn.object; | |
297 | } | |
298 | return ehobject.classinfo; | |
299 | } | |
300 | ||
301 | /** | |
302 | * Convert from pointer to unwindHeader to pointer to ExceptionHeader | |
303 | * that it is embedded inside of. | |
304 | */ | |
305 | static ExceptionHeader* toExceptionHeader(_Unwind_Exception* exc) @nogc | |
306 | { | |
307 | return cast(ExceptionHeader*)(cast(void*)exc - ExceptionHeader.unwindHeader.offsetof); | |
308 | } | |
309 | } | |
310 | ||
311 | /** | |
312 | * Map to C++ std::type_info's virtual functions from D, | |
313 | * being careful to not require linking with libstdc++. | |
314 | * So it is given a different name. | |
315 | */ | |
316 | extern(C++) interface CxxTypeInfo | |
317 | { | |
318 | void dtor1(); | |
319 | void dtor2(); | |
320 | bool __is_pointer_p() const; | |
321 | bool __is_function_p() const; | |
322 | bool __do_catch(const CxxTypeInfo, void**, uint) const; | |
323 | bool __do_upcast(const void*, void**) const; | |
324 | } | |
325 | ||
326 | /** | |
327 | * Structure of a C++ exception, represented as a C structure. | |
328 | * See unwind-cxx.h for the full definition. | |
329 | */ | |
330 | struct CxaExceptionHeader | |
331 | { | |
332 | union | |
333 | { | |
334 | CxxTypeInfo exceptionType; | |
335 | void* primaryException; | |
336 | } | |
337 | void function(void*) exceptionDestructor; | |
338 | void function() unexpectedHandler; | |
339 | void function() terminateHandler; | |
340 | CxaExceptionHeader* nextException; | |
341 | int handlerCount; | |
342 | ||
343 | static if (GNU_ARM_EABI_Unwinder) | |
344 | { | |
345 | CxaExceptionHeader* nextPropagatingException; | |
346 | int propagationCount; | |
347 | } | |
348 | else | |
349 | { | |
350 | int handlerSwitchValue; | |
351 | const(ubyte)* actionRecord; | |
352 | const(ubyte)* languageSpecificData; | |
353 | _Unwind_Ptr catchTemp; | |
354 | void* adjustedPtr; | |
355 | } | |
356 | ||
357 | _Unwind_Exception unwindHeader; | |
358 | ||
359 | /** | |
360 | * There's no saving between phases, so only cache pointer. | |
361 | * __cxa_begin_catch expects this to be set. | |
362 | */ | |
363 | static void save(_Unwind_Exception* unwindHeader, void* thrownPtr) @nogc | |
364 | { | |
365 | static if (GNU_ARM_EABI_Unwinder) | |
366 | unwindHeader.barrier_cache.bitpattern[0] = cast(_uw) thrownPtr; | |
367 | else | |
368 | { | |
369 | auto eh = toExceptionHeader(unwindHeader); | |
370 | eh.adjustedPtr = thrownPtr; | |
371 | } | |
372 | } | |
373 | ||
374 | /** | |
375 | * Get pointer to the thrown object if the thrown object type behind the | |
376 | * exception is implicitly convertible to the catch type. | |
377 | */ | |
378 | static void* getAdjustedPtr(_Unwind_Exception* exc, CxxTypeInfo catchType) | |
379 | { | |
380 | void* thrownPtr; | |
381 | ||
382 | // A dependent C++ exceptions is just a wrapper around the unwind header. | |
383 | // A primary C++ exception has the thrown object located immediately after it. | |
384 | if (isDependentException(exc.exception_class)) | |
385 | thrownPtr = toExceptionHeader(exc).primaryException; | |
386 | else | |
387 | thrownPtr = cast(void*)(exc + 1); | |
388 | ||
389 | // Pointer types need to adjust the actual pointer, not the pointer that is | |
390 | // the exception object. This also has the effect of passing pointer types | |
391 | // "by value" through the __cxa_begin_catch return value. | |
392 | const throw_type = (cast(CxaExceptionHeader*)thrownPtr - 1).exceptionType; | |
393 | ||
394 | if (throw_type.__is_pointer_p()) | |
395 | thrownPtr = *cast(void**)thrownPtr; | |
396 | ||
397 | // Pointer adjustment may be necessary due to multiple inheritance | |
398 | if (catchType is throw_type | |
399 | || catchType.__do_catch(throw_type, &thrownPtr, 1)) | |
400 | return thrownPtr; | |
401 | ||
402 | return null; | |
403 | } | |
404 | ||
405 | /** | |
406 | * Convert from pointer to unwindHeader to pointer to CxaExceptionHeader | |
407 | * that it is embedded inside of. | |
408 | */ | |
409 | static CxaExceptionHeader* toExceptionHeader(_Unwind_Exception* exc) @nogc | |
410 | { | |
411 | return cast(CxaExceptionHeader*)(exc + 1) - 1; | |
412 | } | |
413 | } | |
414 | ||
415 | /** | |
416 | * Called if exception handling must be abandoned for any reason. | |
417 | */ | |
418 | private void terminate(string msg, uint line) @nogc | |
419 | { | |
420 | import core.stdc.stdio; | |
421 | import core.stdc.stdlib; | |
422 | ||
423 | static bool terminating; | |
424 | if (terminating) | |
425 | { | |
426 | fputs("terminate called recursively\n", stderr); | |
427 | abort(); | |
428 | } | |
429 | terminating = true; | |
430 | ||
431 | fprintf(stderr, "gcc.deh(%u): %.*s\n", line, cast(int)msg.length, msg.ptr); | |
432 | ||
433 | abort(); | |
434 | } | |
435 | ||
436 | /** | |
437 | * Called when fibers switch contexts. | |
438 | */ | |
439 | extern(C) void* _d_eh_swapContext(void* newContext) nothrow @nogc | |
440 | { | |
441 | auto old = ExceptionHeader.stack; | |
442 | ExceptionHeader.stack = cast(ExceptionHeader*)newContext; | |
443 | return old; | |
444 | } | |
445 | ||
446 | /** | |
447 | * Called before starting a catch. Returns the exception object. | |
448 | */ | |
449 | extern(C) void* __gdc_begin_catch(_Unwind_Exception* unwindHeader) | |
450 | { | |
451 | ExceptionHeader* header = ExceptionHeader.toExceptionHeader(unwindHeader); | |
452 | ||
453 | void* objectp = cast(void*)header.object; | |
454 | ||
455 | // Something went wrong when stacking up chained headers... | |
456 | if (header != ExceptionHeader.pop()) | |
457 | terminate("catch error", __LINE__); | |
458 | ||
459 | // Handling for this exception is complete. | |
460 | _Unwind_DeleteException(&header.unwindHeader); | |
461 | ||
462 | return objectp; | |
463 | } | |
464 | ||
465 | /** | |
466 | * Perform a throw, D style. Throw will unwind through this call, | |
467 | * so there better not be any handlers or exception thrown here. | |
468 | */ | |
469 | extern(C) void _d_throw(Throwable object) | |
470 | { | |
471 | // If possible, avoid always allocating new memory for exception headers. | |
472 | ExceptionHeader *eh = ExceptionHeader.create(object); | |
473 | ||
474 | // Add to thrown exception stack. | |
475 | eh.push(); | |
476 | ||
477 | // Called by unwinder when exception object needs destruction by other than our code. | |
478 | extern(C) void exception_cleanup(_Unwind_Reason_Code code, _Unwind_Exception* exc) | |
479 | { | |
480 | // If we haven't been caught by a foreign handler, then this is | |
481 | // some sort of unwind error. In that case just die immediately. | |
482 | // _Unwind_DeleteException in the HP-UX IA64 libunwind library | |
483 | // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT | |
484 | // like the GCC _Unwind_DeleteException function does. | |
485 | if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON) | |
486 | terminate("uncaught exception", __LINE__); | |
487 | ||
488 | auto eh = ExceptionHeader.toExceptionHeader(exc); | |
489 | ExceptionHeader.free(eh); | |
490 | } | |
491 | ||
492 | eh.unwindHeader.exception_cleanup = &exception_cleanup; | |
493 | ||
494 | // Runtime now expects us to do this first before unwinding. | |
495 | _d_createTrace(eh.object, null); | |
496 | ||
497 | // We're happy with setjmp/longjmp exceptions or region-based | |
498 | // exception handlers: entry points are provided here for both. | |
499 | _Unwind_Reason_Code r = void; | |
500 | ||
501 | version (GNU_SjLj_Exceptions) | |
502 | r = _Unwind_SjLj_RaiseException(&eh.unwindHeader); | |
503 | else | |
504 | r = _Unwind_RaiseException(&eh.unwindHeader); | |
505 | ||
506 | // If code == _URC_END_OF_STACK, then we reached top of stack without finding | |
507 | // a handler for the exception. Since each thread is run in a try/catch, | |
508 | // this oughtn't happen. If code is something else, we encountered some sort | |
509 | // of heinous lossage from which we could not recover. As is the way of such | |
510 | // things, almost certainly we will have crashed before now, rather than | |
511 | // actually being able to diagnose the problem. | |
512 | if (r == _URC_END_OF_STACK) | |
513 | terminate("uncaught exception", __LINE__); | |
514 | ||
515 | terminate("unwind error", __LINE__); | |
516 | } | |
517 | ||
48528842 RR |
518 | static if (GNU_ARM_EABI_Unwinder) |
519 | { | |
520 | enum personality_fn_attributes = attribute("target", ("general-regs-only")); | |
521 | } | |
522 | else | |
523 | { | |
524 | enum personality_fn_attributes = ""; | |
525 | } | |
b4c522fa IB |
526 | |
527 | /** | |
528 | * Read and extract information from the LSDA (.gcc_except_table section). | |
529 | */ | |
48528842 | 530 | @personality_fn_attributes |
b4c522fa IB |
531 | _Unwind_Reason_Code scanLSDA(const(ubyte)* lsda, _Unwind_Exception_Class exceptionClass, |
532 | _Unwind_Action actions, _Unwind_Exception* unwindHeader, | |
533 | _Unwind_Context* context, _Unwind_Word cfa, | |
534 | out _Unwind_Ptr landingPad, out int handler) | |
535 | { | |
536 | // If no LSDA, then there are no handlers or cleanups. | |
537 | if (lsda is null) | |
538 | return CONTINUE_UNWINDING(unwindHeader, context); | |
539 | ||
540 | // Parse the LSDA header | |
541 | auto p = lsda; | |
542 | ||
543 | auto Start = (context ? _Unwind_GetRegionStart(context) : 0); | |
544 | ||
545 | // Find @LPStart, the base to which landing pad offsets are relative. | |
546 | ubyte LPStartEncoding = *p++; | |
547 | _Unwind_Ptr LPStart = 0; | |
548 | ||
549 | if (LPStartEncoding != DW_EH_PE_omit) | |
30b11d8d | 550 | LPStart = read_encoded_value(context, LPStartEncoding, p); |
b4c522fa IB |
551 | else |
552 | LPStart = Start; | |
553 | ||
554 | // Find @TType, the base of the handler and exception spec type data. | |
555 | ubyte TTypeEncoding = *p++; | |
556 | const(ubyte)* TType = null; | |
557 | ||
558 | if (TTypeEncoding != DW_EH_PE_omit) | |
559 | { | |
560 | static if (__traits(compiles, _TTYPE_ENCODING)) | |
561 | { | |
562 | // Older ARM EABI toolchains set this value incorrectly, so use a | |
563 | // hardcoded OS-specific format. | |
564 | TTypeEncoding = _TTYPE_ENCODING; | |
565 | } | |
30b11d8d | 566 | auto TTbase = read_uleb128(p); |
b4c522fa IB |
567 | TType = p + TTbase; |
568 | } | |
569 | ||
570 | // The encoding and length of the call-site table; the action table | |
571 | // immediately follows. | |
572 | ubyte CSEncoding = *p++; | |
30b11d8d | 573 | auto CSTableSize = read_uleb128(p); |
b4c522fa IB |
574 | const(ubyte)* actionTable = p + CSTableSize; |
575 | ||
576 | auto TTypeBase = base_of_encoded_value(TTypeEncoding, context); | |
577 | ||
578 | // Get instruction pointer (ip) at start of instruction that threw. | |
579 | version (CRuntime_Glibc) | |
580 | { | |
581 | int ip_before_insn; | |
582 | auto ip = _Unwind_GetIPInfo(context, &ip_before_insn); | |
583 | if (!ip_before_insn) | |
584 | --ip; | |
585 | } | |
586 | else | |
587 | { | |
588 | auto ip = _Unwind_GetIP(context); | |
589 | --ip; | |
590 | } | |
591 | ||
592 | bool saw_cleanup = false; | |
593 | bool saw_handler = false; | |
594 | const(ubyte)* actionRecord = null; | |
595 | ||
596 | version (GNU_SjLj_Exceptions) | |
597 | { | |
598 | // The given "IP" is an index into the call-site table, with two | |
599 | // exceptions -- -1 means no-action, and 0 means terminate. | |
600 | // But since we're using uleb128 values, we've not got random | |
601 | // access to the array. | |
602 | if (cast(int) ip <= 0) | |
603 | { | |
604 | return _URC_CONTINUE_UNWIND; | |
605 | } | |
606 | else | |
607 | { | |
608 | _uleb128_t CSLandingPad, CSAction; | |
609 | do | |
610 | { | |
30b11d8d IB |
611 | CSLandingPad = read_uleb128(p); |
612 | CSAction = read_uleb128(p); | |
b4c522fa IB |
613 | } |
614 | while (--ip); | |
615 | ||
616 | // Can never have null landing pad for sjlj -- that would have | |
617 | // been indicated by a -1 call site index. | |
618 | landingPad = CSLandingPad + 1; | |
619 | if (CSAction) | |
620 | actionRecord = actionTable + CSAction - 1; | |
621 | } | |
622 | } | |
623 | else | |
624 | { | |
625 | // Search the call-site table for the action associated with this IP. | |
626 | while (p < actionTable) | |
627 | { | |
628 | // Note that all call-site encodings are "absolute" displacements. | |
30b11d8d IB |
629 | auto CSStart = read_encoded_value(null, CSEncoding, p); |
630 | auto CSLen = read_encoded_value(null, CSEncoding, p); | |
631 | auto CSLandingPad = read_encoded_value(null, CSEncoding, p); | |
632 | auto CSAction = read_uleb128(p); | |
b4c522fa IB |
633 | |
634 | // The table is sorted, so if we've passed the ip, stop. | |
635 | if (ip < Start + CSStart) | |
636 | p = actionTable; | |
637 | else if (ip < Start + CSStart + CSLen) | |
638 | { | |
639 | if (CSLandingPad) | |
640 | landingPad = LPStart + CSLandingPad; | |
641 | if (CSAction) | |
642 | actionRecord = actionTable + CSAction - 1; | |
643 | break; | |
644 | } | |
645 | } | |
646 | } | |
647 | ||
648 | if (landingPad == 0) | |
649 | { | |
650 | // IP is present, but has a null landing pad. | |
651 | // No cleanups or handlers to be run. | |
652 | } | |
653 | else if (actionRecord is null) | |
654 | { | |
655 | // If ip is present, has a non-null landing pad, and a null | |
656 | // action table offset, then there are only cleanups present. | |
657 | // Cleanups use a zero switch value, as set above. | |
658 | saw_cleanup = true; | |
659 | } | |
660 | else | |
661 | { | |
662 | // Otherwise we have a catch handler or exception specification. | |
663 | handler = actionTableLookup(actions, unwindHeader, actionRecord, | |
664 | exceptionClass, TTypeBase, | |
665 | TType, TTypeEncoding, | |
666 | saw_handler, saw_cleanup); | |
667 | } | |
668 | ||
669 | // IP is not in table. No associated cleanups. | |
670 | if (!saw_handler && !saw_cleanup) | |
671 | return CONTINUE_UNWINDING(unwindHeader, context); | |
672 | ||
673 | if (actions & _UA_SEARCH_PHASE) | |
674 | { | |
675 | if (!saw_handler) | |
676 | return CONTINUE_UNWINDING(unwindHeader, context); | |
677 | ||
678 | // For domestic exceptions, we cache data from phase 1 for phase 2. | |
679 | if (isGdcExceptionClass(exceptionClass)) | |
680 | ExceptionHeader.save(unwindHeader, cfa, handler, lsda, landingPad); | |
681 | ||
682 | return _URC_HANDLER_FOUND; | |
683 | } | |
684 | ||
685 | return 0; | |
686 | } | |
687 | ||
688 | /** | |
689 | * Look up and return the handler index of the classType in Action Table. | |
690 | */ | |
691 | int actionTableLookup(_Unwind_Action actions, _Unwind_Exception* unwindHeader, | |
692 | const(ubyte)* actionRecord, _Unwind_Exception_Class exceptionClass, | |
693 | _Unwind_Ptr TTypeBase, const(ubyte)* TType, | |
694 | ubyte TTypeEncoding, | |
695 | out bool saw_handler, out bool saw_cleanup) | |
696 | { | |
697 | ClassInfo thrownType; | |
698 | if (isGdcExceptionClass(exceptionClass)) | |
699 | { | |
700 | thrownType = ExceptionHeader.getClassInfo(unwindHeader); | |
701 | } | |
702 | ||
703 | while (1) | |
704 | { | |
705 | auto ap = actionRecord; | |
30b11d8d | 706 | auto ARFilter = read_sleb128(ap); |
b4c522fa | 707 | auto apn = ap; |
30b11d8d | 708 | auto ARDisp = read_sleb128(ap); |
b4c522fa IB |
709 | |
710 | if (ARFilter == 0) | |
711 | { | |
712 | // Zero filter values are cleanups. | |
713 | saw_cleanup = true; | |
714 | } | |
715 | else if (actions & _UA_FORCE_UNWIND) | |
716 | { | |
717 | // During forced unwinding, we only run cleanups. | |
718 | } | |
719 | else if (ARFilter > 0) | |
720 | { | |
721 | // Positive filter values are handlers. | |
722 | auto encodedSize = size_of_encoded_value(TTypeEncoding); | |
723 | ||
724 | // ARFilter is the negative index from TType, which is where | |
725 | // the ClassInfo is stored. | |
726 | const(ubyte)* tp = TType - ARFilter * encodedSize; | |
727 | ||
30b11d8d | 728 | auto entry = read_encoded_value_with_base(TTypeEncoding, TTypeBase, tp); |
b4c522fa IB |
729 | ClassInfo ci = cast(ClassInfo)cast(void*)(entry); |
730 | ||
731 | // D does not have catch-all handlers, and so the following | |
732 | // assumes that we will never handle a null value. | |
733 | assert(ci !is null); | |
734 | ||
735 | if (ci.classinfo is __cpp_type_info_ptr.classinfo | |
736 | && isGxxExceptionClass(exceptionClass)) | |
737 | { | |
738 | // catchType is the catch clause type_info. | |
739 | auto catchType = cast(CxxTypeInfo)((cast(__cpp_type_info_ptr)cast(void*)ci).ptr); | |
740 | auto thrownPtr = CxaExceptionHeader.getAdjustedPtr(unwindHeader, catchType); | |
741 | ||
742 | if (thrownPtr !is null) | |
743 | { | |
744 | if (actions & _UA_SEARCH_PHASE) | |
745 | CxaExceptionHeader.save(unwindHeader, thrownPtr); | |
746 | saw_handler = true; | |
747 | return cast(int)ARFilter; | |
748 | } | |
749 | } | |
750 | else if (isGdcExceptionClass(exceptionClass) | |
751 | && _d_isbaseof(thrownType, ci)) | |
752 | { | |
753 | saw_handler = true; | |
754 | return cast(int)ARFilter; | |
755 | } | |
756 | else | |
757 | { | |
758 | // ??? What to do about other GNU language exceptions. | |
759 | } | |
760 | } | |
761 | else | |
762 | { | |
763 | // Negative filter values are exception specifications, | |
764 | // which D does not use. | |
765 | break; | |
766 | } | |
767 | ||
768 | if (ARDisp == 0) | |
769 | break; | |
770 | actionRecord = apn + ARDisp; | |
771 | } | |
772 | ||
773 | return 0; | |
774 | } | |
775 | ||
776 | /** | |
777 | * Called when the personality function has found neither a cleanup or handler. | |
778 | * To support ARM EABI personality routines, that must also unwind the stack. | |
779 | */ | |
48528842 | 780 | @personality_fn_attributes |
b4c522fa IB |
781 | _Unwind_Reason_Code CONTINUE_UNWINDING(_Unwind_Exception* unwindHeader, _Unwind_Context* context) |
782 | { | |
783 | static if (GNU_ARM_EABI_Unwinder) | |
784 | { | |
785 | if (__gnu_unwind_frame(unwindHeader, context) != _URC_OK) | |
786 | return _URC_FAILURE; | |
787 | } | |
788 | return _URC_CONTINUE_UNWIND; | |
789 | } | |
790 | ||
791 | /** | |
792 | * Using a different personality function name causes link failures | |
793 | * when trying to mix code using different exception handling models. | |
794 | */ | |
795 | version (GNU_SEH_Exceptions) | |
796 | { | |
797 | enum PERSONALITY_FUNCTION = "__gdc_personality_imp"; | |
798 | ||
799 | extern(C) EXCEPTION_DISPOSITION __gdc_personality_seh0(void* ms_exc, void* this_frame, | |
800 | void* ms_orig_context, void* ms_disp) | |
801 | { | |
802 | return _GCC_specific_handler(ms_exc, this_frame, ms_orig_context, | |
b66e72b4 | 803 | ms_disp, &gdc_personality); |
b4c522fa IB |
804 | } |
805 | } | |
806 | else version (GNU_SjLj_Exceptions) | |
807 | { | |
808 | enum PERSONALITY_FUNCTION = "__gdc_personality_sj0"; | |
809 | ||
810 | private int __builtin_eh_return_data_regno(int x) { return x; } | |
811 | } | |
812 | else | |
813 | { | |
814 | enum PERSONALITY_FUNCTION = "__gdc_personality_v0"; | |
815 | } | |
816 | ||
817 | /** | |
818 | * The "personality" function, specific to each language. | |
819 | */ | |
820 | static if (GNU_ARM_EABI_Unwinder) | |
821 | { | |
822 | pragma(mangle, PERSONALITY_FUNCTION) | |
48528842 | 823 | @personality_fn_attributes |
b4c522fa IB |
824 | extern(C) _Unwind_Reason_Code gdc_personality(_Unwind_State state, |
825 | _Unwind_Exception* unwindHeader, | |
826 | _Unwind_Context* context) | |
827 | { | |
828 | _Unwind_Action actions; | |
829 | ||
830 | switch (state & _US_ACTION_MASK) | |
831 | { | |
832 | case _US_VIRTUAL_UNWIND_FRAME: | |
833 | // If the unwind state pattern is (_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND) | |
834 | // then we don't need to search for any handler as it is not a real exception. | |
835 | // Just unwind the stack. | |
836 | if (state & _US_FORCE_UNWIND) | |
837 | return CONTINUE_UNWINDING(unwindHeader, context); | |
838 | actions = _UA_SEARCH_PHASE; | |
839 | break; | |
840 | ||
841 | case _US_UNWIND_FRAME_STARTING: | |
842 | actions = _UA_CLEANUP_PHASE; | |
843 | if (!(state & _US_FORCE_UNWIND) | |
844 | && unwindHeader.barrier_cache.sp == _Unwind_GetGR(context, UNWIND_STACK_REG)) | |
845 | actions |= _UA_HANDLER_FRAME; | |
846 | break; | |
847 | ||
848 | case _US_UNWIND_FRAME_RESUME: | |
849 | return CONTINUE_UNWINDING(unwindHeader, context); | |
850 | ||
851 | default: | |
852 | terminate("unwind error", __LINE__); | |
853 | } | |
854 | actions |= state & _US_FORCE_UNWIND; | |
855 | ||
856 | // The dwarf unwinder assumes the context structure holds things like | |
857 | // the function and LSDA pointers. The ARM implementation caches these | |
858 | // in the exception header (UCB). To avoid rewriting everything we make | |
859 | // the virtual IP register point at the UCB. | |
860 | _Unwind_SetGR(context, UNWIND_POINTER_REG, cast(_Unwind_Ptr)unwindHeader); | |
861 | ||
862 | return __gdc_personality(actions, unwindHeader.exception_class, | |
863 | unwindHeader, context); | |
864 | } | |
865 | } | |
866 | else | |
867 | { | |
868 | pragma(mangle, PERSONALITY_FUNCTION) | |
869 | extern(C) _Unwind_Reason_Code gdc_personality(int iversion, | |
870 | _Unwind_Action actions, | |
871 | _Unwind_Exception_Class exceptionClass, | |
872 | _Unwind_Exception* unwindHeader, | |
873 | _Unwind_Context* context) | |
874 | { | |
875 | // Interface version check. | |
876 | if (iversion != 1) | |
877 | return _URC_FATAL_PHASE1_ERROR; | |
878 | ||
879 | return __gdc_personality(actions, exceptionClass, unwindHeader, context); | |
880 | } | |
881 | } | |
882 | ||
48528842 | 883 | @personality_fn_attributes |
b4c522fa IB |
884 | private _Unwind_Reason_Code __gdc_personality(_Unwind_Action actions, |
885 | _Unwind_Exception_Class exceptionClass, | |
886 | _Unwind_Exception* unwindHeader, | |
887 | _Unwind_Context* context) | |
888 | { | |
889 | const(ubyte)* lsda; | |
890 | _Unwind_Ptr landingPad; | |
891 | _Unwind_Word cfa; | |
892 | int handler; | |
893 | ||
894 | // Shortcut for phase 2 found handler for domestic exception. | |
895 | if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME) | |
896 | && isGdcExceptionClass(exceptionClass)) | |
897 | { | |
898 | ExceptionHeader.restore(unwindHeader, handler, lsda, landingPad, cfa); | |
899 | // Shouldn't have cached a null landing pad in phase 1. | |
900 | if (landingPad == 0) | |
901 | terminate("unwind error", __LINE__); | |
902 | } | |
903 | else | |
904 | { | |
905 | lsda = cast(ubyte*)_Unwind_GetLanguageSpecificData(context); | |
906 | ||
907 | static if (GNU_ARM_EABI_Unwinder) | |
908 | cfa = _Unwind_GetGR(context, UNWIND_STACK_REG); | |
909 | else | |
910 | cfa = _Unwind_GetCFA(context); | |
911 | ||
912 | auto result = scanLSDA(lsda, exceptionClass, actions, unwindHeader, | |
913 | context, cfa, landingPad, handler); | |
914 | ||
915 | // Positive on handler found in phase 1, continue unwinding, or failure. | |
916 | if (result) | |
917 | return result; | |
918 | } | |
919 | ||
920 | // Unexpected negative handler, call terminate directly. | |
921 | if (handler < 0) | |
922 | terminate("unwind error", __LINE__); | |
923 | ||
924 | // We can't use any of the deh routines with foreign exceptions, | |
925 | // because they all expect unwindHeader to be an ExceptionHeader. | |
926 | if (isGdcExceptionClass(exceptionClass)) | |
927 | { | |
928 | // If there are any in-flight exceptions being thrown, chain our | |
929 | // current object onto the end of the prevous object. | |
930 | ExceptionHeader* eh = ExceptionHeader.toExceptionHeader(unwindHeader); | |
931 | auto currentLsd = lsda; | |
932 | auto currentCfa = cfa; | |
933 | bool bypassed = false; | |
934 | ||
935 | while (eh.next) | |
936 | { | |
937 | ExceptionHeader* ehn = eh.next; | |
938 | const(ubyte)* nextLsd; | |
939 | _Unwind_Ptr nextLandingPad; | |
940 | _Unwind_Word nextCfa; | |
941 | int nextHandler; | |
942 | ||
943 | ExceptionHeader.restore(&ehn.unwindHeader, nextHandler, nextLsd, nextLandingPad, nextCfa); | |
944 | ||
945 | Error e = cast(Error)eh.object; | |
946 | if (e !is null && !cast(Error)ehn.object) | |
947 | { | |
948 | // We found an Error, bypass the exception chain. | |
949 | currentLsd = nextLsd; | |
950 | currentCfa = nextCfa; | |
951 | eh = ehn; | |
952 | bypassed = true; | |
953 | continue; | |
954 | } | |
955 | ||
956 | // Don't combine when the exceptions are from different functions. | |
957 | if (currentLsd != nextLsd && currentCfa != nextCfa) | |
958 | break; | |
959 | ||
960 | // Add our object onto the end of the existing chain. | |
961 | Throwable n = ehn.object; | |
962 | while (n.next) | |
963 | n = n.next; | |
964 | n.next = eh.object; | |
965 | ||
966 | // Replace our exception object with in-flight one | |
967 | eh.object = ehn.object; | |
968 | if (nextHandler != handler && !bypassed) | |
969 | { | |
970 | handler = nextHandler; | |
971 | ExceptionHeader.save(unwindHeader, cfa, handler, lsda, landingPad); | |
972 | } | |
973 | ||
974 | // Exceptions chained, can now throw away the previous header. | |
975 | eh.next = ehn.next; | |
976 | _Unwind_DeleteException(&ehn.unwindHeader); | |
977 | } | |
978 | ||
979 | if (bypassed) | |
980 | { | |
981 | eh = ExceptionHeader.toExceptionHeader(unwindHeader); | |
982 | Error e = cast(Error)eh.object; | |
983 | auto ehn = eh.next; | |
984 | e.bypassedException = ehn.object; | |
985 | eh.next = ehn.next; | |
986 | _Unwind_DeleteException(&ehn.unwindHeader); | |
987 | } | |
988 | } | |
989 | ||
990 | // Set up registers and jump to cleanup or handler. | |
991 | // For targets with pointers smaller than the word size, we must extend the | |
992 | // pointer, and this extension is target dependent. | |
993 | _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), | |
994 | cast(_Unwind_Ptr)unwindHeader); | |
995 | _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), handler); | |
996 | _Unwind_SetIP(context, landingPad); | |
997 | ||
998 | return _URC_INSTALL_CONTEXT; | |
999 | } |