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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*); | |
37 | ||
38 | // Not used in GDC but declaration required by rt/sections.d | |
39 | struct FuncTable | |
40 | { | |
41 | } | |
42 | } | |
43 | ||
44 | /** | |
45 | * Declare all known and handled exception classes. | |
46 | * D exceptions -- "GNUCD\0\0\0". | |
47 | * C++ exceptions -- "GNUCC++\0" | |
48 | * C++ dependent exceptions -- "GNUCC++\x01" | |
49 | */ | |
50 | static if (GNU_ARM_EABI_Unwinder) | |
51 | { | |
52 | enum _Unwind_Exception_Class gdcExceptionClass = "GNUCD\0\0\0"; | |
53 | enum _Unwind_Exception_Class gxxExceptionClass = "GNUCC++\0"; | |
54 | enum _Unwind_Exception_Class gxxDependentExceptionClass = "GNUCC++\x01"; | |
55 | } | |
56 | else | |
57 | { | |
58 | enum _Unwind_Exception_Class gdcExceptionClass = | |
59 | (cast(_Unwind_Exception_Class)'G' << 56) | | |
60 | (cast(_Unwind_Exception_Class)'N' << 48) | | |
61 | (cast(_Unwind_Exception_Class)'U' << 40) | | |
62 | (cast(_Unwind_Exception_Class)'C' << 32) | | |
63 | (cast(_Unwind_Exception_Class)'D' << 24); | |
64 | ||
65 | enum _Unwind_Exception_Class gxxExceptionClass = | |
66 | (cast(_Unwind_Exception_Class)'G' << 56) | | |
67 | (cast(_Unwind_Exception_Class)'N' << 48) | | |
68 | (cast(_Unwind_Exception_Class)'U' << 40) | | |
69 | (cast(_Unwind_Exception_Class)'C' << 32) | | |
70 | (cast(_Unwind_Exception_Class)'C' << 24) | | |
71 | (cast(_Unwind_Exception_Class)'+' << 16) | | |
72 | (cast(_Unwind_Exception_Class)'+' << 8) | | |
73 | (cast(_Unwind_Exception_Class)0 << 0); | |
74 | ||
75 | enum _Unwind_Exception_Class gxxDependentExceptionClass = | |
76 | gxxExceptionClass + 1; | |
77 | } | |
78 | ||
79 | /** | |
80 | * Checks for GDC exception class. | |
81 | */ | |
82 | bool isGdcExceptionClass(_Unwind_Exception_Class c) @nogc | |
83 | { | |
84 | static if (GNU_ARM_EABI_Unwinder) | |
85 | { | |
86 | return c[0] == gdcExceptionClass[0] | |
87 | && c[1] == gdcExceptionClass[1] | |
88 | && c[2] == gdcExceptionClass[2] | |
89 | && c[3] == gdcExceptionClass[3] | |
90 | && c[4] == gdcExceptionClass[4] | |
91 | && c[5] == gdcExceptionClass[5] | |
92 | && c[6] == gdcExceptionClass[6] | |
93 | && c[7] == gdcExceptionClass[7]; | |
94 | } | |
95 | else | |
96 | { | |
97 | return c == gdcExceptionClass; | |
98 | } | |
99 | } | |
100 | ||
101 | /** | |
102 | * Checks for any C++ exception class. | |
103 | */ | |
104 | bool isGxxExceptionClass(_Unwind_Exception_Class c) @nogc | |
105 | { | |
106 | static if (GNU_ARM_EABI_Unwinder) | |
107 | { | |
108 | return c[0] == gxxExceptionClass[0] | |
109 | && c[1] == gxxExceptionClass[1] | |
110 | && c[2] == gxxExceptionClass[2] | |
111 | && c[3] == gxxExceptionClass[3] | |
112 | && c[4] == gxxExceptionClass[4] | |
113 | && c[5] == gxxExceptionClass[5] | |
114 | && c[6] == gxxExceptionClass[6] | |
115 | && (c[7] == gxxExceptionClass[7] | |
116 | || c[7] == gxxDependentExceptionClass[7]); | |
117 | } | |
118 | else | |
119 | { | |
120 | return c == gxxExceptionClass | |
121 | || c == gxxDependentExceptionClass; | |
122 | } | |
123 | } | |
124 | ||
125 | /** | |
126 | * Checks for primary or dependent, but not that it is a C++ exception. | |
127 | */ | |
128 | bool isDependentException(_Unwind_Exception_Class c) @nogc | |
129 | { | |
130 | static if (GNU_ARM_EABI_Unwinder) | |
131 | return (c[7] == '\x01'); | |
132 | else | |
133 | return (c & 1); | |
134 | } | |
135 | ||
136 | /** | |
137 | * A D exception object consists of a header, which is a wrapper | |
138 | * around an unwind object header with additional D specific | |
139 | * information, prefixed by the exception object itself. | |
140 | */ | |
141 | struct ExceptionHeader | |
142 | { | |
143 | // Because of a lack of __aligned__ style attribute, our object | |
144 | // and the unwind object are the first two fields. | |
145 | static if (Throwable.alignof < _Unwind_Exception.alignof) | |
146 | ubyte[_Unwind_Exception.alignof - Throwable.alignof] pad; | |
147 | ||
148 | // The object being thrown. The compiled code expects this to | |
149 | // be immediately before the generic exception header. | |
150 | Throwable object; | |
151 | ||
152 | // The generic exception header. | |
153 | _Unwind_Exception unwindHeader; | |
154 | ||
155 | static assert(unwindHeader.offsetof - object.offsetof == object.sizeof); | |
156 | ||
157 | // Cache handler details between Phase 1 and Phase 2. | |
158 | static if (GNU_ARM_EABI_Unwinder) | |
159 | { | |
160 | // Nothing here yet. | |
161 | } | |
162 | else | |
163 | { | |
164 | // Which catch was found. | |
165 | int handler; | |
166 | ||
167 | // Language Specific Data Area for function enclosing the handler. | |
168 | const(ubyte)* languageSpecificData; | |
169 | ||
170 | // Pointer to catch code. | |
171 | _Unwind_Ptr landingPad; | |
172 | ||
173 | // Canonical Frame Address (CFA) for the enclosing handler. | |
174 | _Unwind_Word canonicalFrameAddress; | |
175 | } | |
176 | ||
177 | // Stack other thrown exceptions in current thread through here. | |
178 | ExceptionHeader* next; | |
179 | ||
180 | // Thread local stack of chained exceptions. | |
181 | static ExceptionHeader* stack; | |
182 | ||
183 | // Pre-allocate storage for 1 instance per thread. | |
184 | // Use calloc/free for multiple exceptions in flight. | |
185 | static ExceptionHeader ehstorage; | |
186 | ||
187 | /** | |
188 | * Allocate and initialize an ExceptionHeader. | |
189 | */ | |
190 | static ExceptionHeader* create(Throwable o) @nogc | |
191 | { | |
192 | auto eh = &ehstorage; | |
193 | ||
194 | // Check exception object in use. | |
195 | if (eh.object) | |
196 | { | |
197 | eh = cast(ExceptionHeader*) __builtin_calloc(ExceptionHeader.sizeof, 1); | |
198 | // Out of memory while throwing - not much else can be done. | |
199 | if (!eh) | |
200 | terminate("out of memory", __LINE__); | |
201 | } | |
202 | eh.object = o; | |
203 | ||
204 | eh.unwindHeader.exception_class = gdcExceptionClass; | |
205 | ||
206 | return eh; | |
207 | } | |
208 | ||
209 | /** | |
210 | * Free ExceptionHeader that was created by create(). | |
211 | */ | |
212 | static void free(ExceptionHeader* eh) @nogc | |
213 | { | |
214 | *eh = ExceptionHeader.init; | |
215 | if (eh != &ehstorage) | |
216 | __builtin_free(eh); | |
217 | } | |
218 | ||
219 | /** | |
220 | * Push this onto stack of chained exceptions. | |
221 | */ | |
222 | void push() @nogc | |
223 | { | |
224 | next = stack; | |
225 | stack = &this; | |
226 | } | |
227 | ||
228 | /** | |
229 | * Pop and return top of chained exception stack. | |
230 | */ | |
231 | static ExceptionHeader* pop() @nogc | |
232 | { | |
233 | auto eh = stack; | |
234 | stack = eh.next; | |
235 | return eh; | |
236 | } | |
237 | ||
238 | /** | |
239 | * Save stage1 handler information in the exception object. | |
240 | */ | |
241 | static void save(_Unwind_Exception* unwindHeader, | |
242 | _Unwind_Word cfa, int handler, | |
243 | const(ubyte)* lsda, _Unwind_Ptr landingPad) @nogc | |
244 | { | |
245 | static if (GNU_ARM_EABI_Unwinder) | |
246 | { | |
247 | unwindHeader.barrier_cache.sp = cfa; | |
248 | unwindHeader.barrier_cache.bitpattern[1] = cast(_uw)handler; | |
249 | unwindHeader.barrier_cache.bitpattern[2] = cast(_uw)lsda; | |
250 | unwindHeader.barrier_cache.bitpattern[3] = cast(_uw)landingPad; | |
251 | } | |
252 | else | |
253 | { | |
254 | ExceptionHeader* eh = toExceptionHeader(unwindHeader); | |
255 | eh.canonicalFrameAddress = cfa; | |
256 | eh.handler = handler; | |
257 | eh.languageSpecificData = lsda; | |
258 | eh.landingPad = landingPad; | |
259 | } | |
260 | } | |
261 | ||
262 | /** | |
263 | * Restore the catch handler data saved during phase1. | |
264 | */ | |
265 | static void restore(_Unwind_Exception* unwindHeader, out int handler, | |
266 | out const(ubyte)* lsda, out _Unwind_Ptr landingPad, | |
267 | out _Unwind_Word cfa) @nogc | |
268 | { | |
269 | static if (GNU_ARM_EABI_Unwinder) | |
270 | { | |
271 | cfa = unwindHeader.barrier_cache.sp; | |
272 | handler = cast(int)unwindHeader.barrier_cache.bitpattern[1]; | |
273 | lsda = cast(ubyte*)unwindHeader.barrier_cache.bitpattern[2]; | |
274 | landingPad = cast(_Unwind_Ptr)unwindHeader.barrier_cache.bitpattern[3]; | |
275 | } | |
276 | else | |
277 | { | |
278 | ExceptionHeader* eh = toExceptionHeader(unwindHeader); | |
279 | cfa = eh.canonicalFrameAddress; | |
280 | handler = eh.handler; | |
281 | lsda = eh.languageSpecificData; | |
282 | landingPad = cast(_Unwind_Ptr)eh.landingPad; | |
283 | } | |
284 | } | |
285 | ||
286 | /** | |
287 | * Look at the chain of inflight exceptions and pick the class type that'll | |
288 | * be looked for in catch clauses. | |
289 | */ | |
290 | static ClassInfo getClassInfo(_Unwind_Exception* unwindHeader) @nogc | |
291 | { | |
292 | ExceptionHeader* eh = toExceptionHeader(unwindHeader); | |
293 | // The first thrown Exception at the top of the stack takes precedence | |
294 | // over others that are inflight, unless an Error was thrown, in which | |
295 | // case, we search for error handlers instead. | |
296 | Throwable ehobject = eh.object; | |
297 | for (ExceptionHeader* ehn = eh.next; ehn; ehn = ehn.next) | |
298 | { | |
299 | Error e = cast(Error)ehobject; | |
300 | if (e is null || (cast(Error)ehn.object) !is null) | |
301 | ehobject = ehn.object; | |
302 | } | |
303 | return ehobject.classinfo; | |
304 | } | |
305 | ||
306 | /** | |
307 | * Convert from pointer to unwindHeader to pointer to ExceptionHeader | |
308 | * that it is embedded inside of. | |
309 | */ | |
310 | static ExceptionHeader* toExceptionHeader(_Unwind_Exception* exc) @nogc | |
311 | { | |
312 | return cast(ExceptionHeader*)(cast(void*)exc - ExceptionHeader.unwindHeader.offsetof); | |
313 | } | |
314 | } | |
315 | ||
316 | /** | |
317 | * Map to C++ std::type_info's virtual functions from D, | |
318 | * being careful to not require linking with libstdc++. | |
319 | * So it is given a different name. | |
320 | */ | |
321 | extern(C++) interface CxxTypeInfo | |
322 | { | |
323 | void dtor1(); | |
324 | void dtor2(); | |
325 | bool __is_pointer_p() const; | |
326 | bool __is_function_p() const; | |
327 | bool __do_catch(const CxxTypeInfo, void**, uint) const; | |
328 | bool __do_upcast(const void*, void**) const; | |
329 | } | |
330 | ||
331 | /** | |
332 | * Structure of a C++ exception, represented as a C structure. | |
333 | * See unwind-cxx.h for the full definition. | |
334 | */ | |
335 | struct CxaExceptionHeader | |
336 | { | |
337 | union | |
338 | { | |
339 | CxxTypeInfo exceptionType; | |
340 | void* primaryException; | |
341 | } | |
342 | void function(void*) exceptionDestructor; | |
343 | void function() unexpectedHandler; | |
344 | void function() terminateHandler; | |
345 | CxaExceptionHeader* nextException; | |
346 | int handlerCount; | |
347 | ||
348 | static if (GNU_ARM_EABI_Unwinder) | |
349 | { | |
350 | CxaExceptionHeader* nextPropagatingException; | |
351 | int propagationCount; | |
352 | } | |
353 | else | |
354 | { | |
355 | int handlerSwitchValue; | |
356 | const(ubyte)* actionRecord; | |
357 | const(ubyte)* languageSpecificData; | |
358 | _Unwind_Ptr catchTemp; | |
359 | void* adjustedPtr; | |
360 | } | |
361 | ||
362 | _Unwind_Exception unwindHeader; | |
363 | ||
364 | /** | |
365 | * There's no saving between phases, so only cache pointer. | |
366 | * __cxa_begin_catch expects this to be set. | |
367 | */ | |
368 | static void save(_Unwind_Exception* unwindHeader, void* thrownPtr) @nogc | |
369 | { | |
370 | static if (GNU_ARM_EABI_Unwinder) | |
371 | unwindHeader.barrier_cache.bitpattern[0] = cast(_uw) thrownPtr; | |
372 | else | |
373 | { | |
374 | auto eh = toExceptionHeader(unwindHeader); | |
375 | eh.adjustedPtr = thrownPtr; | |
376 | } | |
377 | } | |
378 | ||
379 | /** | |
380 | * Get pointer to the thrown object if the thrown object type behind the | |
381 | * exception is implicitly convertible to the catch type. | |
382 | */ | |
383 | static void* getAdjustedPtr(_Unwind_Exception* exc, CxxTypeInfo catchType) | |
384 | { | |
385 | void* thrownPtr; | |
386 | ||
387 | // A dependent C++ exceptions is just a wrapper around the unwind header. | |
388 | // A primary C++ exception has the thrown object located immediately after it. | |
389 | if (isDependentException(exc.exception_class)) | |
390 | thrownPtr = toExceptionHeader(exc).primaryException; | |
391 | else | |
392 | thrownPtr = cast(void*)(exc + 1); | |
393 | ||
394 | // Pointer types need to adjust the actual pointer, not the pointer that is | |
395 | // the exception object. This also has the effect of passing pointer types | |
396 | // "by value" through the __cxa_begin_catch return value. | |
397 | const throw_type = (cast(CxaExceptionHeader*)thrownPtr - 1).exceptionType; | |
398 | ||
399 | if (throw_type.__is_pointer_p()) | |
400 | thrownPtr = *cast(void**)thrownPtr; | |
401 | ||
402 | // Pointer adjustment may be necessary due to multiple inheritance | |
403 | if (catchType is throw_type | |
404 | || catchType.__do_catch(throw_type, &thrownPtr, 1)) | |
405 | return thrownPtr; | |
406 | ||
407 | return null; | |
408 | } | |
409 | ||
410 | /** | |
411 | * Convert from pointer to unwindHeader to pointer to CxaExceptionHeader | |
412 | * that it is embedded inside of. | |
413 | */ | |
414 | static CxaExceptionHeader* toExceptionHeader(_Unwind_Exception* exc) @nogc | |
415 | { | |
416 | return cast(CxaExceptionHeader*)(exc + 1) - 1; | |
417 | } | |
418 | } | |
419 | ||
420 | /** | |
421 | * Called if exception handling must be abandoned for any reason. | |
422 | */ | |
423 | private void terminate(string msg, uint line) @nogc | |
424 | { | |
425 | import core.stdc.stdio; | |
426 | import core.stdc.stdlib; | |
427 | ||
428 | static bool terminating; | |
429 | if (terminating) | |
430 | { | |
431 | fputs("terminate called recursively\n", stderr); | |
432 | abort(); | |
433 | } | |
434 | terminating = true; | |
435 | ||
436 | fprintf(stderr, "gcc.deh(%u): %.*s\n", line, cast(int)msg.length, msg.ptr); | |
437 | ||
438 | abort(); | |
439 | } | |
440 | ||
441 | /** | |
442 | * Called when fibers switch contexts. | |
443 | */ | |
444 | extern(C) void* _d_eh_swapContext(void* newContext) nothrow @nogc | |
445 | { | |
446 | auto old = ExceptionHeader.stack; | |
447 | ExceptionHeader.stack = cast(ExceptionHeader*)newContext; | |
448 | return old; | |
449 | } | |
450 | ||
451 | /** | |
452 | * Called before starting a catch. Returns the exception object. | |
453 | */ | |
454 | extern(C) void* __gdc_begin_catch(_Unwind_Exception* unwindHeader) | |
455 | { | |
456 | ExceptionHeader* header = ExceptionHeader.toExceptionHeader(unwindHeader); | |
457 | ||
458 | void* objectp = cast(void*)header.object; | |
459 | ||
460 | // Something went wrong when stacking up chained headers... | |
461 | if (header != ExceptionHeader.pop()) | |
462 | terminate("catch error", __LINE__); | |
463 | ||
464 | // Handling for this exception is complete. | |
465 | _Unwind_DeleteException(&header.unwindHeader); | |
466 | ||
467 | return objectp; | |
468 | } | |
469 | ||
470 | /** | |
471 | * Perform a throw, D style. Throw will unwind through this call, | |
472 | * so there better not be any handlers or exception thrown here. | |
473 | */ | |
474 | extern(C) void _d_throw(Throwable object) | |
475 | { | |
476 | // If possible, avoid always allocating new memory for exception headers. | |
477 | ExceptionHeader *eh = ExceptionHeader.create(object); | |
478 | ||
479 | // Add to thrown exception stack. | |
480 | eh.push(); | |
481 | ||
482 | // Called by unwinder when exception object needs destruction by other than our code. | |
483 | extern(C) void exception_cleanup(_Unwind_Reason_Code code, _Unwind_Exception* exc) | |
484 | { | |
485 | // If we haven't been caught by a foreign handler, then this is | |
486 | // some sort of unwind error. In that case just die immediately. | |
487 | // _Unwind_DeleteException in the HP-UX IA64 libunwind library | |
488 | // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT | |
489 | // like the GCC _Unwind_DeleteException function does. | |
490 | if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON) | |
491 | terminate("uncaught exception", __LINE__); | |
492 | ||
493 | auto eh = ExceptionHeader.toExceptionHeader(exc); | |
494 | ExceptionHeader.free(eh); | |
495 | } | |
496 | ||
497 | eh.unwindHeader.exception_cleanup = &exception_cleanup; | |
498 | ||
499 | // Runtime now expects us to do this first before unwinding. | |
500 | _d_createTrace(eh.object, null); | |
501 | ||
502 | // We're happy with setjmp/longjmp exceptions or region-based | |
503 | // exception handlers: entry points are provided here for both. | |
504 | _Unwind_Reason_Code r = void; | |
505 | ||
506 | version (GNU_SjLj_Exceptions) | |
507 | r = _Unwind_SjLj_RaiseException(&eh.unwindHeader); | |
508 | else | |
509 | r = _Unwind_RaiseException(&eh.unwindHeader); | |
510 | ||
511 | // If code == _URC_END_OF_STACK, then we reached top of stack without finding | |
512 | // a handler for the exception. Since each thread is run in a try/catch, | |
513 | // this oughtn't happen. If code is something else, we encountered some sort | |
514 | // of heinous lossage from which we could not recover. As is the way of such | |
515 | // things, almost certainly we will have crashed before now, rather than | |
516 | // actually being able to diagnose the problem. | |
517 | if (r == _URC_END_OF_STACK) | |
518 | terminate("uncaught exception", __LINE__); | |
519 | ||
520 | terminate("unwind error", __LINE__); | |
521 | } | |
522 | ||
48528842 RR |
523 | static if (GNU_ARM_EABI_Unwinder) |
524 | { | |
525 | enum personality_fn_attributes = attribute("target", ("general-regs-only")); | |
526 | } | |
527 | else | |
528 | { | |
529 | enum personality_fn_attributes = ""; | |
530 | } | |
b4c522fa IB |
531 | |
532 | /** | |
533 | * Read and extract information from the LSDA (.gcc_except_table section). | |
534 | */ | |
48528842 | 535 | @personality_fn_attributes |
b4c522fa IB |
536 | _Unwind_Reason_Code scanLSDA(const(ubyte)* lsda, _Unwind_Exception_Class exceptionClass, |
537 | _Unwind_Action actions, _Unwind_Exception* unwindHeader, | |
538 | _Unwind_Context* context, _Unwind_Word cfa, | |
539 | out _Unwind_Ptr landingPad, out int handler) | |
540 | { | |
541 | // If no LSDA, then there are no handlers or cleanups. | |
542 | if (lsda is null) | |
543 | return CONTINUE_UNWINDING(unwindHeader, context); | |
544 | ||
545 | // Parse the LSDA header | |
546 | auto p = lsda; | |
547 | ||
548 | auto Start = (context ? _Unwind_GetRegionStart(context) : 0); | |
549 | ||
550 | // Find @LPStart, the base to which landing pad offsets are relative. | |
551 | ubyte LPStartEncoding = *p++; | |
552 | _Unwind_Ptr LPStart = 0; | |
553 | ||
554 | if (LPStartEncoding != DW_EH_PE_omit) | |
555 | LPStart = read_encoded_value(context, LPStartEncoding, &p); | |
556 | else | |
557 | LPStart = Start; | |
558 | ||
559 | // Find @TType, the base of the handler and exception spec type data. | |
560 | ubyte TTypeEncoding = *p++; | |
561 | const(ubyte)* TType = null; | |
562 | ||
563 | if (TTypeEncoding != DW_EH_PE_omit) | |
564 | { | |
565 | static if (__traits(compiles, _TTYPE_ENCODING)) | |
566 | { | |
567 | // Older ARM EABI toolchains set this value incorrectly, so use a | |
568 | // hardcoded OS-specific format. | |
569 | TTypeEncoding = _TTYPE_ENCODING; | |
570 | } | |
571 | auto TTbase = read_uleb128(&p); | |
572 | TType = p + TTbase; | |
573 | } | |
574 | ||
575 | // The encoding and length of the call-site table; the action table | |
576 | // immediately follows. | |
577 | ubyte CSEncoding = *p++; | |
578 | auto CSTableSize = read_uleb128(&p); | |
579 | const(ubyte)* actionTable = p + CSTableSize; | |
580 | ||
581 | auto TTypeBase = base_of_encoded_value(TTypeEncoding, context); | |
582 | ||
583 | // Get instruction pointer (ip) at start of instruction that threw. | |
584 | version (CRuntime_Glibc) | |
585 | { | |
586 | int ip_before_insn; | |
587 | auto ip = _Unwind_GetIPInfo(context, &ip_before_insn); | |
588 | if (!ip_before_insn) | |
589 | --ip; | |
590 | } | |
591 | else | |
592 | { | |
593 | auto ip = _Unwind_GetIP(context); | |
594 | --ip; | |
595 | } | |
596 | ||
597 | bool saw_cleanup = false; | |
598 | bool saw_handler = false; | |
599 | const(ubyte)* actionRecord = null; | |
600 | ||
601 | version (GNU_SjLj_Exceptions) | |
602 | { | |
603 | // The given "IP" is an index into the call-site table, with two | |
604 | // exceptions -- -1 means no-action, and 0 means terminate. | |
605 | // But since we're using uleb128 values, we've not got random | |
606 | // access to the array. | |
607 | if (cast(int) ip <= 0) | |
608 | { | |
609 | return _URC_CONTINUE_UNWIND; | |
610 | } | |
611 | else | |
612 | { | |
613 | _uleb128_t CSLandingPad, CSAction; | |
614 | do | |
615 | { | |
616 | CSLandingPad = read_uleb128(&p); | |
617 | CSAction = read_uleb128(&p); | |
618 | } | |
619 | while (--ip); | |
620 | ||
621 | // Can never have null landing pad for sjlj -- that would have | |
622 | // been indicated by a -1 call site index. | |
623 | landingPad = CSLandingPad + 1; | |
624 | if (CSAction) | |
625 | actionRecord = actionTable + CSAction - 1; | |
626 | } | |
627 | } | |
628 | else | |
629 | { | |
630 | // Search the call-site table for the action associated with this IP. | |
631 | while (p < actionTable) | |
632 | { | |
633 | // Note that all call-site encodings are "absolute" displacements. | |
634 | auto CSStart = read_encoded_value(null, CSEncoding, &p); | |
635 | auto CSLen = read_encoded_value(null, CSEncoding, &p); | |
636 | auto CSLandingPad = read_encoded_value(null, CSEncoding, &p); | |
637 | auto CSAction = read_uleb128(&p); | |
638 | ||
639 | // The table is sorted, so if we've passed the ip, stop. | |
640 | if (ip < Start + CSStart) | |
641 | p = actionTable; | |
642 | else if (ip < Start + CSStart + CSLen) | |
643 | { | |
644 | if (CSLandingPad) | |
645 | landingPad = LPStart + CSLandingPad; | |
646 | if (CSAction) | |
647 | actionRecord = actionTable + CSAction - 1; | |
648 | break; | |
649 | } | |
650 | } | |
651 | } | |
652 | ||
653 | if (landingPad == 0) | |
654 | { | |
655 | // IP is present, but has a null landing pad. | |
656 | // No cleanups or handlers to be run. | |
657 | } | |
658 | else if (actionRecord is null) | |
659 | { | |
660 | // If ip is present, has a non-null landing pad, and a null | |
661 | // action table offset, then there are only cleanups present. | |
662 | // Cleanups use a zero switch value, as set above. | |
663 | saw_cleanup = true; | |
664 | } | |
665 | else | |
666 | { | |
667 | // Otherwise we have a catch handler or exception specification. | |
668 | handler = actionTableLookup(actions, unwindHeader, actionRecord, | |
669 | exceptionClass, TTypeBase, | |
670 | TType, TTypeEncoding, | |
671 | saw_handler, saw_cleanup); | |
672 | } | |
673 | ||
674 | // IP is not in table. No associated cleanups. | |
675 | if (!saw_handler && !saw_cleanup) | |
676 | return CONTINUE_UNWINDING(unwindHeader, context); | |
677 | ||
678 | if (actions & _UA_SEARCH_PHASE) | |
679 | { | |
680 | if (!saw_handler) | |
681 | return CONTINUE_UNWINDING(unwindHeader, context); | |
682 | ||
683 | // For domestic exceptions, we cache data from phase 1 for phase 2. | |
684 | if (isGdcExceptionClass(exceptionClass)) | |
685 | ExceptionHeader.save(unwindHeader, cfa, handler, lsda, landingPad); | |
686 | ||
687 | return _URC_HANDLER_FOUND; | |
688 | } | |
689 | ||
690 | return 0; | |
691 | } | |
692 | ||
693 | /** | |
694 | * Look up and return the handler index of the classType in Action Table. | |
695 | */ | |
696 | int actionTableLookup(_Unwind_Action actions, _Unwind_Exception* unwindHeader, | |
697 | const(ubyte)* actionRecord, _Unwind_Exception_Class exceptionClass, | |
698 | _Unwind_Ptr TTypeBase, const(ubyte)* TType, | |
699 | ubyte TTypeEncoding, | |
700 | out bool saw_handler, out bool saw_cleanup) | |
701 | { | |
702 | ClassInfo thrownType; | |
703 | if (isGdcExceptionClass(exceptionClass)) | |
704 | { | |
705 | thrownType = ExceptionHeader.getClassInfo(unwindHeader); | |
706 | } | |
707 | ||
708 | while (1) | |
709 | { | |
710 | auto ap = actionRecord; | |
711 | auto ARFilter = read_sleb128(&ap); | |
712 | auto apn = ap; | |
713 | auto ARDisp = read_sleb128(&ap); | |
714 | ||
715 | if (ARFilter == 0) | |
716 | { | |
717 | // Zero filter values are cleanups. | |
718 | saw_cleanup = true; | |
719 | } | |
720 | else if (actions & _UA_FORCE_UNWIND) | |
721 | { | |
722 | // During forced unwinding, we only run cleanups. | |
723 | } | |
724 | else if (ARFilter > 0) | |
725 | { | |
726 | // Positive filter values are handlers. | |
727 | auto encodedSize = size_of_encoded_value(TTypeEncoding); | |
728 | ||
729 | // ARFilter is the negative index from TType, which is where | |
730 | // the ClassInfo is stored. | |
731 | const(ubyte)* tp = TType - ARFilter * encodedSize; | |
732 | ||
733 | auto entry = read_encoded_value_with_base(TTypeEncoding, TTypeBase, &tp); | |
734 | ClassInfo ci = cast(ClassInfo)cast(void*)(entry); | |
735 | ||
736 | // D does not have catch-all handlers, and so the following | |
737 | // assumes that we will never handle a null value. | |
738 | assert(ci !is null); | |
739 | ||
740 | if (ci.classinfo is __cpp_type_info_ptr.classinfo | |
741 | && isGxxExceptionClass(exceptionClass)) | |
742 | { | |
743 | // catchType is the catch clause type_info. | |
744 | auto catchType = cast(CxxTypeInfo)((cast(__cpp_type_info_ptr)cast(void*)ci).ptr); | |
745 | auto thrownPtr = CxaExceptionHeader.getAdjustedPtr(unwindHeader, catchType); | |
746 | ||
747 | if (thrownPtr !is null) | |
748 | { | |
749 | if (actions & _UA_SEARCH_PHASE) | |
750 | CxaExceptionHeader.save(unwindHeader, thrownPtr); | |
751 | saw_handler = true; | |
752 | return cast(int)ARFilter; | |
753 | } | |
754 | } | |
755 | else if (isGdcExceptionClass(exceptionClass) | |
756 | && _d_isbaseof(thrownType, ci)) | |
757 | { | |
758 | saw_handler = true; | |
759 | return cast(int)ARFilter; | |
760 | } | |
761 | else | |
762 | { | |
763 | // ??? What to do about other GNU language exceptions. | |
764 | } | |
765 | } | |
766 | else | |
767 | { | |
768 | // Negative filter values are exception specifications, | |
769 | // which D does not use. | |
770 | break; | |
771 | } | |
772 | ||
773 | if (ARDisp == 0) | |
774 | break; | |
775 | actionRecord = apn + ARDisp; | |
776 | } | |
777 | ||
778 | return 0; | |
779 | } | |
780 | ||
781 | /** | |
782 | * Called when the personality function has found neither a cleanup or handler. | |
783 | * To support ARM EABI personality routines, that must also unwind the stack. | |
784 | */ | |
48528842 | 785 | @personality_fn_attributes |
b4c522fa IB |
786 | _Unwind_Reason_Code CONTINUE_UNWINDING(_Unwind_Exception* unwindHeader, _Unwind_Context* context) |
787 | { | |
788 | static if (GNU_ARM_EABI_Unwinder) | |
789 | { | |
790 | if (__gnu_unwind_frame(unwindHeader, context) != _URC_OK) | |
791 | return _URC_FAILURE; | |
792 | } | |
793 | return _URC_CONTINUE_UNWIND; | |
794 | } | |
795 | ||
796 | /** | |
797 | * Using a different personality function name causes link failures | |
798 | * when trying to mix code using different exception handling models. | |
799 | */ | |
800 | version (GNU_SEH_Exceptions) | |
801 | { | |
802 | enum PERSONALITY_FUNCTION = "__gdc_personality_imp"; | |
803 | ||
804 | extern(C) EXCEPTION_DISPOSITION __gdc_personality_seh0(void* ms_exc, void* this_frame, | |
805 | void* ms_orig_context, void* ms_disp) | |
806 | { | |
807 | return _GCC_specific_handler(ms_exc, this_frame, ms_orig_context, | |
808 | ms_disp, &__gdc_personality_imp); | |
809 | } | |
810 | } | |
811 | else version (GNU_SjLj_Exceptions) | |
812 | { | |
813 | enum PERSONALITY_FUNCTION = "__gdc_personality_sj0"; | |
814 | ||
815 | private int __builtin_eh_return_data_regno(int x) { return x; } | |
816 | } | |
817 | else | |
818 | { | |
819 | enum PERSONALITY_FUNCTION = "__gdc_personality_v0"; | |
820 | } | |
821 | ||
822 | /** | |
823 | * The "personality" function, specific to each language. | |
824 | */ | |
825 | static if (GNU_ARM_EABI_Unwinder) | |
826 | { | |
827 | pragma(mangle, PERSONALITY_FUNCTION) | |
48528842 | 828 | @personality_fn_attributes |
b4c522fa IB |
829 | extern(C) _Unwind_Reason_Code gdc_personality(_Unwind_State state, |
830 | _Unwind_Exception* unwindHeader, | |
831 | _Unwind_Context* context) | |
832 | { | |
833 | _Unwind_Action actions; | |
834 | ||
835 | switch (state & _US_ACTION_MASK) | |
836 | { | |
837 | case _US_VIRTUAL_UNWIND_FRAME: | |
838 | // If the unwind state pattern is (_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND) | |
839 | // then we don't need to search for any handler as it is not a real exception. | |
840 | // Just unwind the stack. | |
841 | if (state & _US_FORCE_UNWIND) | |
842 | return CONTINUE_UNWINDING(unwindHeader, context); | |
843 | actions = _UA_SEARCH_PHASE; | |
844 | break; | |
845 | ||
846 | case _US_UNWIND_FRAME_STARTING: | |
847 | actions = _UA_CLEANUP_PHASE; | |
848 | if (!(state & _US_FORCE_UNWIND) | |
849 | && unwindHeader.barrier_cache.sp == _Unwind_GetGR(context, UNWIND_STACK_REG)) | |
850 | actions |= _UA_HANDLER_FRAME; | |
851 | break; | |
852 | ||
853 | case _US_UNWIND_FRAME_RESUME: | |
854 | return CONTINUE_UNWINDING(unwindHeader, context); | |
855 | ||
856 | default: | |
857 | terminate("unwind error", __LINE__); | |
858 | } | |
859 | actions |= state & _US_FORCE_UNWIND; | |
860 | ||
861 | // The dwarf unwinder assumes the context structure holds things like | |
862 | // the function and LSDA pointers. The ARM implementation caches these | |
863 | // in the exception header (UCB). To avoid rewriting everything we make | |
864 | // the virtual IP register point at the UCB. | |
865 | _Unwind_SetGR(context, UNWIND_POINTER_REG, cast(_Unwind_Ptr)unwindHeader); | |
866 | ||
867 | return __gdc_personality(actions, unwindHeader.exception_class, | |
868 | unwindHeader, context); | |
869 | } | |
870 | } | |
871 | else | |
872 | { | |
873 | pragma(mangle, PERSONALITY_FUNCTION) | |
874 | extern(C) _Unwind_Reason_Code gdc_personality(int iversion, | |
875 | _Unwind_Action actions, | |
876 | _Unwind_Exception_Class exceptionClass, | |
877 | _Unwind_Exception* unwindHeader, | |
878 | _Unwind_Context* context) | |
879 | { | |
880 | // Interface version check. | |
881 | if (iversion != 1) | |
882 | return _URC_FATAL_PHASE1_ERROR; | |
883 | ||
884 | return __gdc_personality(actions, exceptionClass, unwindHeader, context); | |
885 | } | |
886 | } | |
887 | ||
48528842 | 888 | @personality_fn_attributes |
b4c522fa IB |
889 | private _Unwind_Reason_Code __gdc_personality(_Unwind_Action actions, |
890 | _Unwind_Exception_Class exceptionClass, | |
891 | _Unwind_Exception* unwindHeader, | |
892 | _Unwind_Context* context) | |
893 | { | |
894 | const(ubyte)* lsda; | |
895 | _Unwind_Ptr landingPad; | |
896 | _Unwind_Word cfa; | |
897 | int handler; | |
898 | ||
899 | // Shortcut for phase 2 found handler for domestic exception. | |
900 | if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME) | |
901 | && isGdcExceptionClass(exceptionClass)) | |
902 | { | |
903 | ExceptionHeader.restore(unwindHeader, handler, lsda, landingPad, cfa); | |
904 | // Shouldn't have cached a null landing pad in phase 1. | |
905 | if (landingPad == 0) | |
906 | terminate("unwind error", __LINE__); | |
907 | } | |
908 | else | |
909 | { | |
910 | lsda = cast(ubyte*)_Unwind_GetLanguageSpecificData(context); | |
911 | ||
912 | static if (GNU_ARM_EABI_Unwinder) | |
913 | cfa = _Unwind_GetGR(context, UNWIND_STACK_REG); | |
914 | else | |
915 | cfa = _Unwind_GetCFA(context); | |
916 | ||
917 | auto result = scanLSDA(lsda, exceptionClass, actions, unwindHeader, | |
918 | context, cfa, landingPad, handler); | |
919 | ||
920 | // Positive on handler found in phase 1, continue unwinding, or failure. | |
921 | if (result) | |
922 | return result; | |
923 | } | |
924 | ||
925 | // Unexpected negative handler, call terminate directly. | |
926 | if (handler < 0) | |
927 | terminate("unwind error", __LINE__); | |
928 | ||
929 | // We can't use any of the deh routines with foreign exceptions, | |
930 | // because they all expect unwindHeader to be an ExceptionHeader. | |
931 | if (isGdcExceptionClass(exceptionClass)) | |
932 | { | |
933 | // If there are any in-flight exceptions being thrown, chain our | |
934 | // current object onto the end of the prevous object. | |
935 | ExceptionHeader* eh = ExceptionHeader.toExceptionHeader(unwindHeader); | |
936 | auto currentLsd = lsda; | |
937 | auto currentCfa = cfa; | |
938 | bool bypassed = false; | |
939 | ||
940 | while (eh.next) | |
941 | { | |
942 | ExceptionHeader* ehn = eh.next; | |
943 | const(ubyte)* nextLsd; | |
944 | _Unwind_Ptr nextLandingPad; | |
945 | _Unwind_Word nextCfa; | |
946 | int nextHandler; | |
947 | ||
948 | ExceptionHeader.restore(&ehn.unwindHeader, nextHandler, nextLsd, nextLandingPad, nextCfa); | |
949 | ||
950 | Error e = cast(Error)eh.object; | |
951 | if (e !is null && !cast(Error)ehn.object) | |
952 | { | |
953 | // We found an Error, bypass the exception chain. | |
954 | currentLsd = nextLsd; | |
955 | currentCfa = nextCfa; | |
956 | eh = ehn; | |
957 | bypassed = true; | |
958 | continue; | |
959 | } | |
960 | ||
961 | // Don't combine when the exceptions are from different functions. | |
962 | if (currentLsd != nextLsd && currentCfa != nextCfa) | |
963 | break; | |
964 | ||
965 | // Add our object onto the end of the existing chain. | |
966 | Throwable n = ehn.object; | |
967 | while (n.next) | |
968 | n = n.next; | |
969 | n.next = eh.object; | |
970 | ||
971 | // Replace our exception object with in-flight one | |
972 | eh.object = ehn.object; | |
973 | if (nextHandler != handler && !bypassed) | |
974 | { | |
975 | handler = nextHandler; | |
976 | ExceptionHeader.save(unwindHeader, cfa, handler, lsda, landingPad); | |
977 | } | |
978 | ||
979 | // Exceptions chained, can now throw away the previous header. | |
980 | eh.next = ehn.next; | |
981 | _Unwind_DeleteException(&ehn.unwindHeader); | |
982 | } | |
983 | ||
984 | if (bypassed) | |
985 | { | |
986 | eh = ExceptionHeader.toExceptionHeader(unwindHeader); | |
987 | Error e = cast(Error)eh.object; | |
988 | auto ehn = eh.next; | |
989 | e.bypassedException = ehn.object; | |
990 | eh.next = ehn.next; | |
991 | _Unwind_DeleteException(&ehn.unwindHeader); | |
992 | } | |
993 | } | |
994 | ||
995 | // Set up registers and jump to cleanup or handler. | |
996 | // For targets with pointers smaller than the word size, we must extend the | |
997 | // pointer, and this extension is target dependent. | |
998 | _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), | |
999 | cast(_Unwind_Ptr)unwindHeader); | |
1000 | _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), handler); | |
1001 | _Unwind_SetIP(context, landingPad); | |
1002 | ||
1003 | return _URC_INSTALL_CONTEXT; | |
1004 | } |