1 //===------------------------- UnwindLevel1.c -----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
9 // Implements C++ ABI Exception Handling Level 1 as documented at:
10 // http://mentorembedded.github.io/cxx-abi/abi-eh.html
13 //===----------------------------------------------------------------------===//
15 // ARM EHABI does not specify _Unwind_{Get,Set}{GR,IP}(). Thus, we are
16 // defining inline functions to delegate the function calls to
17 // _Unwind_VRS_{Get,Set}(). However, some applications might declare the
18 // function protetype directly (instead of including <unwind.h>), thus we need
19 // to export these functions from libunwind.so as well.
20 #define _LIBUNWIND_UNWIND_LEVEL1_EXTERNAL_LINKAGE 1
29 #include "libunwind.h"
33 #if !defined(_LIBUNWIND_ARM_EHABI) && !defined(__USING_SJLJ_EXCEPTIONS__)
35 #ifndef _LIBUNWIND_SUPPORT_SEH_UNWIND
37 static _Unwind_Reason_Code
38 unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) {
39 unw_init_local(cursor, uc);
41 // Walk each frame looking for a place to stop.
42 bool handlerNotFound = true;
43 while (handlerNotFound) {
44 // Ask libunwind to get next frame (skip over first which is
45 // _Unwind_RaiseException).
46 int stepResult = unw_step(cursor);
47 if (stepResult == 0) {
48 _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step() reached "
49 "bottom => _URC_END_OF_STACK",
50 (void *)exception_object);
51 return _URC_END_OF_STACK;
52 } else if (stepResult < 0) {
53 _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step failed => "
54 "_URC_FATAL_PHASE1_ERROR",
55 (void *)exception_object);
56 return _URC_FATAL_PHASE1_ERROR;
59 // See if frame has code to run (has personality routine).
60 unw_proc_info_t frameInfo;
62 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) {
63 _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_get_proc_info "
64 "failed => _URC_FATAL_PHASE1_ERROR",
65 (void *)exception_object);
66 return _URC_FATAL_PHASE1_ERROR;
69 // When tracing, print state information.
70 if (_LIBUNWIND_TRACING_UNWINDING) {
71 char functionBuf[512];
72 const char *functionName = functionBuf;
74 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf),
75 &offset) != UNW_ESUCCESS) ||
76 (frameInfo.start_ip + offset > frameInfo.end_ip))
77 functionName = ".anonymous.";
79 unw_get_reg(cursor, UNW_REG_IP, &pc);
80 _LIBUNWIND_TRACE_UNWINDING(
81 "unwind_phase1(ex_ojb=%p): pc=0x%" PRIxPTR ", start_ip=0x%" PRIxPTR
82 ", func=%s, lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR "",
83 (void *)exception_object, pc, frameInfo.start_ip, functionName,
84 frameInfo.lsda, frameInfo.handler);
87 // If there is a personality routine, ask it if it will want to stop at
89 if (frameInfo.handler != 0) {
90 __personality_routine p =
91 (__personality_routine)(uintptr_t)(frameInfo.handler);
92 _LIBUNWIND_TRACE_UNWINDING(
93 "unwind_phase1(ex_ojb=%p): calling personality function %p",
94 (void *)exception_object, (void *)(uintptr_t)p);
95 _Unwind_Reason_Code personalityResult =
96 (*p)(1, _UA_SEARCH_PHASE, exception_object->exception_class,
97 exception_object, (struct _Unwind_Context *)(cursor));
98 switch (personalityResult) {
99 case _URC_HANDLER_FOUND:
100 // found a catch clause or locals that need destructing in this frame
101 // stop search and remember stack pointer at the frame
102 handlerNotFound = false;
103 unw_get_reg(cursor, UNW_REG_SP, &sp);
104 exception_object->private_2 = (uintptr_t)sp;
105 _LIBUNWIND_TRACE_UNWINDING(
106 "unwind_phase1(ex_ojb=%p): _URC_HANDLER_FOUND",
107 (void *)exception_object);
108 return _URC_NO_REASON;
110 case _URC_CONTINUE_UNWIND:
111 _LIBUNWIND_TRACE_UNWINDING(
112 "unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND",
113 (void *)exception_object);
114 // continue unwinding
118 // something went wrong
119 _LIBUNWIND_TRACE_UNWINDING(
120 "unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR",
121 (void *)exception_object);
122 return _URC_FATAL_PHASE1_ERROR;
126 return _URC_NO_REASON;
130 static _Unwind_Reason_Code
131 unwind_phase2(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) {
132 unw_init_local(cursor, uc);
134 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)",
135 (void *)exception_object);
137 // Walk each frame until we reach where search phase said to stop.
140 // Ask libunwind to get next frame (skip over first which is
141 // _Unwind_RaiseException).
142 int stepResult = unw_step(cursor);
143 if (stepResult == 0) {
144 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step() reached "
145 "bottom => _URC_END_OF_STACK",
146 (void *)exception_object);
147 return _URC_END_OF_STACK;
148 } else if (stepResult < 0) {
149 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step failed => "
150 "_URC_FATAL_PHASE1_ERROR",
151 (void *)exception_object);
152 return _URC_FATAL_PHASE2_ERROR;
155 // Get info about this frame.
157 unw_proc_info_t frameInfo;
158 unw_get_reg(cursor, UNW_REG_SP, &sp);
159 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) {
160 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_get_proc_info "
161 "failed => _URC_FATAL_PHASE1_ERROR",
162 (void *)exception_object);
163 return _URC_FATAL_PHASE2_ERROR;
166 // When tracing, print state information.
167 if (_LIBUNWIND_TRACING_UNWINDING) {
168 char functionBuf[512];
169 const char *functionName = functionBuf;
171 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf),
172 &offset) != UNW_ESUCCESS) ||
173 (frameInfo.start_ip + offset > frameInfo.end_ip))
174 functionName = ".anonymous.";
175 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): start_ip=0x%" PRIxPTR
176 ", func=%s, sp=0x%" PRIxPTR ", lsda=0x%" PRIxPTR
177 ", personality=0x%" PRIxPTR,
178 (void *)exception_object, frameInfo.start_ip,
179 functionName, sp, frameInfo.lsda,
183 // If there is a personality routine, tell it we are unwinding.
184 if (frameInfo.handler != 0) {
185 __personality_routine p =
186 (__personality_routine)(uintptr_t)(frameInfo.handler);
187 _Unwind_Action action = _UA_CLEANUP_PHASE;
188 if (sp == exception_object->private_2) {
189 // Tell personality this was the frame it marked in phase 1.
190 action = (_Unwind_Action)(_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME);
192 _Unwind_Reason_Code personalityResult =
193 (*p)(1, action, exception_object->exception_class, exception_object,
194 (struct _Unwind_Context *)(cursor));
195 switch (personalityResult) {
196 case _URC_CONTINUE_UNWIND:
197 // Continue unwinding
198 _LIBUNWIND_TRACE_UNWINDING(
199 "unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND",
200 (void *)exception_object);
201 if (sp == exception_object->private_2) {
202 // Phase 1 said we would stop at this frame, but we did not...
203 _LIBUNWIND_ABORT("during phase1 personality function said it would "
204 "stop here, but now in phase2 it did not stop here");
207 case _URC_INSTALL_CONTEXT:
208 _LIBUNWIND_TRACE_UNWINDING(
209 "unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT",
210 (void *)exception_object);
211 // Personality routine says to transfer control to landing pad.
212 // We may get control back if landing pad calls _Unwind_Resume().
213 if (_LIBUNWIND_TRACING_UNWINDING) {
215 unw_get_reg(cursor, UNW_REG_IP, &pc);
216 unw_get_reg(cursor, UNW_REG_SP, &sp);
217 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering "
218 "user code with ip=0x%" PRIxPTR
220 (void *)exception_object, pc, sp);
223 // unw_resume() only returns if there was an error.
224 return _URC_FATAL_PHASE2_ERROR;
226 // Personality routine returned an unknown result code.
227 _LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d",
229 return _URC_FATAL_PHASE2_ERROR;
234 // Clean up phase did not resume at the frame that the search phase
236 return _URC_FATAL_PHASE2_ERROR;
239 static _Unwind_Reason_Code
240 unwind_phase2_forced(unw_context_t *uc, unw_cursor_t *cursor,
241 _Unwind_Exception *exception_object,
242 _Unwind_Stop_Fn stop, void *stop_parameter) {
243 unw_init_local(cursor, uc);
245 // Walk each frame until we reach where search phase said to stop
246 while (unw_step(cursor) > 0) {
248 // Update info about this frame.
249 unw_proc_info_t frameInfo;
250 if (unw_get_proc_info(cursor, &frameInfo) != UNW_ESUCCESS) {
251 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): unw_step "
252 "failed => _URC_END_OF_STACK",
253 (void *)exception_object);
254 return _URC_FATAL_PHASE2_ERROR;
257 // When tracing, print state information.
258 if (_LIBUNWIND_TRACING_UNWINDING) {
259 char functionBuf[512];
260 const char *functionName = functionBuf;
262 if ((unw_get_proc_name(cursor, functionBuf, sizeof(functionBuf),
263 &offset) != UNW_ESUCCESS) ||
264 (frameInfo.start_ip + offset > frameInfo.end_ip))
265 functionName = ".anonymous.";
266 _LIBUNWIND_TRACE_UNWINDING(
267 "unwind_phase2_forced(ex_ojb=%p): start_ip=0x%" PRIxPTR
268 ", func=%s, lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR,
269 (void *)exception_object, frameInfo.start_ip, functionName,
270 frameInfo.lsda, frameInfo.handler);
273 // Call stop function at each frame.
274 _Unwind_Action action =
275 (_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE);
276 _Unwind_Reason_Code stopResult =
277 (*stop)(1, action, exception_object->exception_class, exception_object,
278 (struct _Unwind_Context *)(cursor), stop_parameter);
279 _LIBUNWIND_TRACE_UNWINDING(
280 "unwind_phase2_forced(ex_ojb=%p): stop function returned %d",
281 (void *)exception_object, stopResult);
282 if (stopResult != _URC_NO_REASON) {
283 _LIBUNWIND_TRACE_UNWINDING(
284 "unwind_phase2_forced(ex_ojb=%p): stopped by stop function",
285 (void *)exception_object);
286 return _URC_FATAL_PHASE2_ERROR;
289 // If there is a personality routine, tell it we are unwinding.
290 if (frameInfo.handler != 0) {
291 __personality_routine p =
292 (__personality_routine)(intptr_t)(frameInfo.handler);
293 _LIBUNWIND_TRACE_UNWINDING(
294 "unwind_phase2_forced(ex_ojb=%p): calling personality function %p",
295 (void *)exception_object, (void *)(uintptr_t)p);
296 _Unwind_Reason_Code personalityResult =
297 (*p)(1, action, exception_object->exception_class, exception_object,
298 (struct _Unwind_Context *)(cursor));
299 switch (personalityResult) {
300 case _URC_CONTINUE_UNWIND:
301 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
302 "personality returned "
303 "_URC_CONTINUE_UNWIND",
304 (void *)exception_object);
305 // Destructors called, continue unwinding
307 case _URC_INSTALL_CONTEXT:
308 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
309 "personality returned "
310 "_URC_INSTALL_CONTEXT",
311 (void *)exception_object);
312 // We may get control back if landing pad calls _Unwind_Resume().
316 // Personality routine returned an unknown result code.
317 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
318 "personality returned %d, "
319 "_URC_FATAL_PHASE2_ERROR",
320 (void *)exception_object, personalityResult);
321 return _URC_FATAL_PHASE2_ERROR;
326 // Call stop function one last time and tell it we've reached the end
328 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): calling stop "
329 "function with _UA_END_OF_STACK",
330 (void *)exception_object);
331 _Unwind_Action lastAction =
332 (_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE | _UA_END_OF_STACK);
333 (*stop)(1, lastAction, exception_object->exception_class, exception_object,
334 (struct _Unwind_Context *)(cursor), stop_parameter);
336 // Clean up phase did not resume at the frame that the search phase said it
338 return _URC_FATAL_PHASE2_ERROR;
342 /// Called by __cxa_throw. Only returns if there is a fatal error.
343 _LIBUNWIND_EXPORT _Unwind_Reason_Code
344 _Unwind_RaiseException(_Unwind_Exception *exception_object) {
345 _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)",
346 (void *)exception_object);
351 // Mark that this is a non-forced unwind, so _Unwind_Resume()
352 // can do the right thing.
353 exception_object->private_1 = 0;
354 exception_object->private_2 = 0;
356 // phase 1: the search phase
357 _Unwind_Reason_Code phase1 = unwind_phase1(&uc, &cursor, exception_object);
358 if (phase1 != _URC_NO_REASON)
361 // phase 2: the clean up phase
362 return unwind_phase2(&uc, &cursor, exception_object);
367 /// When _Unwind_RaiseException() is in phase2, it hands control
368 /// to the personality function at each frame. The personality
369 /// may force a jump to a landing pad in that function, the landing
370 /// pad code may then call _Unwind_Resume() to continue with the
371 /// unwinding. Note: the call to _Unwind_Resume() is from compiler
372 /// geneated user code. All other _Unwind_* routines are called
373 /// by the C++ runtime __cxa_* routines.
375 /// Note: re-throwing an exception (as opposed to continuing the unwind)
376 /// is implemented by having the code call __cxa_rethrow() which
377 /// in turn calls _Unwind_Resume_or_Rethrow().
378 _LIBUNWIND_EXPORT void
379 _Unwind_Resume(_Unwind_Exception *exception_object) {
380 _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)", (void *)exception_object);
385 if (exception_object->private_1 != 0)
386 unwind_phase2_forced(&uc, &cursor, exception_object,
387 (_Unwind_Stop_Fn) exception_object->private_1,
388 (void *)exception_object->private_2);
390 unwind_phase2(&uc, &cursor, exception_object);
392 // Clients assume _Unwind_Resume() does not return, so all we can do is abort.
393 _LIBUNWIND_ABORT("_Unwind_Resume() can't return");
399 /// Unwinds stack, calling "stop" function at each frame.
400 /// Could be used to implement longjmp().
401 _LIBUNWIND_EXPORT _Unwind_Reason_Code
402 _Unwind_ForcedUnwind(_Unwind_Exception *exception_object,
403 _Unwind_Stop_Fn stop, void *stop_parameter) {
404 _LIBUNWIND_TRACE_API("_Unwind_ForcedUnwind(ex_obj=%p, stop=%p)",
405 (void *)exception_object, (void *)(uintptr_t)stop);
410 // Mark that this is a forced unwind, so _Unwind_Resume() can do
412 exception_object->private_1 = (uintptr_t) stop;
413 exception_object->private_2 = (uintptr_t) stop_parameter;
416 return unwind_phase2_forced(&uc, &cursor, exception_object, stop, stop_parameter);
420 /// Called by personality handler during phase 2 to get LSDA for current frame.
421 _LIBUNWIND_EXPORT uintptr_t
422 _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) {
423 unw_cursor_t *cursor = (unw_cursor_t *)context;
424 unw_proc_info_t frameInfo;
425 uintptr_t result = 0;
426 if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS)
427 result = (uintptr_t)frameInfo.lsda;
428 _LIBUNWIND_TRACE_API(
429 "_Unwind_GetLanguageSpecificData(context=%p) => 0x%" PRIxPTR,
430 (void *)context, result);
432 if (*((uint8_t *)result) != 0xFF)
433 _LIBUNWIND_DEBUG_LOG("lsda at 0x%" PRIxPTR " does not start with 0xFF",
440 /// Called by personality handler during phase 2 to find the start of the
442 _LIBUNWIND_EXPORT uintptr_t
443 _Unwind_GetRegionStart(struct _Unwind_Context *context) {
444 unw_cursor_t *cursor = (unw_cursor_t *)context;
445 unw_proc_info_t frameInfo;
446 uintptr_t result = 0;
447 if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS)
448 result = (uintptr_t)frameInfo.start_ip;
449 _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%" PRIxPTR,
450 (void *)context, result);
454 #endif // !_LIBUNWIND_SUPPORT_SEH_UNWIND
456 /// Called by personality handler during phase 2 if a foreign exception
458 _LIBUNWIND_EXPORT void
459 _Unwind_DeleteException(_Unwind_Exception *exception_object) {
460 _LIBUNWIND_TRACE_API("_Unwind_DeleteException(ex_obj=%p)",
461 (void *)exception_object);
462 if (exception_object->exception_cleanup != NULL)
463 (*exception_object->exception_cleanup)(_URC_FOREIGN_EXCEPTION_CAUGHT,
467 /// Called by personality handler during phase 2 to get register values.
468 _LIBUNWIND_EXPORT uintptr_t
469 _Unwind_GetGR(struct _Unwind_Context *context, int index) {
470 unw_cursor_t *cursor = (unw_cursor_t *)context;
472 unw_get_reg(cursor, index, &result);
473 _LIBUNWIND_TRACE_API("_Unwind_GetGR(context=%p, reg=%d) => 0x%" PRIxPTR,
474 (void *)context, index, result);
475 return (uintptr_t)result;
478 /// Called by personality handler during phase 2 to alter register values.
479 _LIBUNWIND_EXPORT void _Unwind_SetGR(struct _Unwind_Context *context, int index,
481 _LIBUNWIND_TRACE_API("_Unwind_SetGR(context=%p, reg=%d, value=0x%0" PRIxPTR
483 (void *)context, index, value);
484 unw_cursor_t *cursor = (unw_cursor_t *)context;
485 unw_set_reg(cursor, index, value);
488 /// Called by personality handler during phase 2 to get instruction pointer.
489 _LIBUNWIND_EXPORT uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
490 unw_cursor_t *cursor = (unw_cursor_t *)context;
492 unw_get_reg(cursor, UNW_REG_IP, &result);
493 _LIBUNWIND_TRACE_API("_Unwind_GetIP(context=%p) => 0x%" PRIxPTR,
494 (void *)context, result);
495 return (uintptr_t)result;
498 /// Called by personality handler during phase 2 to alter instruction pointer,
499 /// such as setting where the landing pad is, so _Unwind_Resume() will
500 /// start executing in the landing pad.
501 _LIBUNWIND_EXPORT void _Unwind_SetIP(struct _Unwind_Context *context,
503 _LIBUNWIND_TRACE_API("_Unwind_SetIP(context=%p, value=0x%0" PRIxPTR ")",
504 (void *)context, value);
505 unw_cursor_t *cursor = (unw_cursor_t *)context;
506 unw_set_reg(cursor, UNW_REG_IP, value);
509 #endif // !defined(_LIBUNWIND_ARM_EHABI) && !defined(__USING_SJLJ_EXCEPTIONS__)