1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Implements SEH-based Itanium C++ exceptions.
10//
11//===----------------------------------------------------------------------===//
12
13#include "config.h"
14
15#if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
16
17#include <unwind.h>
18
19#include <stdint.h>
20#include <stdbool.h>
21#include <stdlib.h>
22
23#include <windef.h>
24#include <excpt.h>
25#include <winnt.h>
26#include <ntstatus.h>
27
28#include "libunwind_ext.h"
29#include "UnwindCursor.hpp"
30
31using namespace libunwind;
32
33#define STATUS_USER_DEFINED (1u << 29)
34
35#define STATUS_GCC_MAGIC (('G' << 16) | ('C' << 8) | 'C')
36
37#define MAKE_CUSTOM_STATUS(s, c) \
38 ((NTSTATUS)(((s) << 30) | STATUS_USER_DEFINED | (c)))
39#define MAKE_GCC_EXCEPTION(c) \
40 MAKE_CUSTOM_STATUS(STATUS_SEVERITY_SUCCESS, STATUS_GCC_MAGIC | ((c) << 24))
41
42/// SEH exception raised by libunwind when the program calls
43/// \c _Unwind_RaiseException.
44#define STATUS_GCC_THROW MAKE_GCC_EXCEPTION(0) // 0x20474343
45/// SEH exception raised by libunwind to initiate phase 2 of exception
46/// handling.
47#define STATUS_GCC_UNWIND MAKE_GCC_EXCEPTION(1) // 0x21474343
48
49static int __unw_init_seh(unw_cursor_t *cursor, CONTEXT *ctx);
50static DISPATCHER_CONTEXT *__unw_seh_get_disp_ctx(unw_cursor_t *cursor);
51static void __unw_seh_set_disp_ctx(unw_cursor_t *cursor,
52 DISPATCHER_CONTEXT *disp);
53
54#pragma clang diagnostic push
55#pragma clang diagnostic ignored "-Wgnu-anonymous-struct"
56// Local redefinition of this type; mingw-w64 headers lack the
57// DISPATCHER_CONTEXT_NONVOLREG_ARM64 type as of May 2025, so locally redefine
58// it and use that definition, to avoid needing to test/guess whether the real
59// type is available of not.
60union LOCAL_DISPATCHER_CONTEXT_NONVOLREG_ARM64 {
61 BYTE Buffer[11 * sizeof(DWORD64) + 8 * sizeof(double)];
62
63 struct {
64 DWORD64 GpNvRegs[11];
65 double FpNvRegs[8];
66 };
67};
68
69// Custom data type definition; this type is not defined in WinSDK.
70union LOCAL_DISPATCHER_CONTEXT_NONVOLREG_ARM {
71 BYTE Buffer[8 * sizeof(DWORD) + 8 * sizeof(double)];
72
73 struct {
74 DWORD GpNvRegs[8];
75 double FpNvRegs[8];
76 };
77};
78#pragma clang diagnostic pop
79
80/// Common implementation of SEH-style handler functions used by Itanium-
81/// style frames. Depending on how and why it was called, it may do one of:
82/// a) Delegate to the given Itanium-style personality function; or
83/// b) Initiate a collided unwind to halt unwinding.
84_LIBUNWIND_EXPORT EXCEPTION_DISPOSITION
85_GCC_specific_handler(PEXCEPTION_RECORD ms_exc, PVOID frame, PCONTEXT ms_ctx,
86 DISPATCHER_CONTEXT *disp, _Unwind_Personality_Fn pers) {
87 unw_cursor_t cursor;
88 _Unwind_Exception *exc;
89 _Unwind_Action action;
90 struct _Unwind_Context *ctx = nullptr;
91 _Unwind_Reason_Code urc;
92 uintptr_t retval, target;
93 bool ours = false;
94
95 _LIBUNWIND_TRACE_UNWINDING("_GCC_specific_handler(%#010lx(%lx), %p)",
96 ms_exc->ExceptionCode, ms_exc->ExceptionFlags,
97 (void *)frame);
98 if (ms_exc->ExceptionCode == STATUS_GCC_UNWIND) {
99 if (IS_TARGET_UNWIND(ms_exc->ExceptionFlags)) {
100 // Set up the upper return value (the lower one and the target PC
101 // were set in the call to RtlUnwindEx()) for the landing pad.
102#ifdef __x86_64__
103 disp->ContextRecord->Rdx = ms_exc->ExceptionInformation[3];
104#elif defined(__arm__)
105 disp->ContextRecord->R1 = ms_exc->ExceptionInformation[3];
106#elif defined(__aarch64__)
107 disp->ContextRecord->X1 = ms_exc->ExceptionInformation[3];
108#endif
109 }
110 // This is the collided unwind to the landing pad. Nothing to do.
111 return ExceptionContinueSearch;
112 }
113
114 if (ms_exc->ExceptionCode == STATUS_GCC_THROW) {
115 // This is (probably) a libunwind-controlled exception/unwind. Recover the
116 // parameters which we set below, and pass them to the personality function.
117 ours = true;
118 exc = (_Unwind_Exception *)ms_exc->ExceptionInformation[0];
119 if (!IS_UNWINDING(ms_exc->ExceptionFlags) && ms_exc->NumberParameters > 1) {
120 ctx = (struct _Unwind_Context *)ms_exc->ExceptionInformation[1];
121 action = (_Unwind_Action)ms_exc->ExceptionInformation[2];
122 }
123 } else {
124 // Foreign exception.
125 // We can't interact with them (we don't know the original target frame
126 // that we should pass on to RtlUnwindEx in _Unwind_Resume), so just
127 // pass without calling our destructors here.
128 return ExceptionContinueSearch;
129 }
130 if (!ctx) {
131 __unw_init_seh(&cursor, disp->ContextRecord);
132 __unw_seh_set_disp_ctx(&cursor, disp);
133 __unw_set_reg(&cursor, UNW_REG_IP, disp->ControlPc);
134 ctx = (struct _Unwind_Context *)&cursor;
135
136 if (!IS_UNWINDING(ms_exc->ExceptionFlags)) {
137 if (ours && ms_exc->NumberParameters > 1)
138 action = (_Unwind_Action)(_UA_CLEANUP_PHASE | _UA_FORCE_UNWIND);
139 else
140 action = _UA_SEARCH_PHASE;
141 } else {
142 if (ours && ms_exc->ExceptionInformation[1] == (ULONG_PTR)frame)
143 action = (_Unwind_Action)(_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME);
144 else
145 action = _UA_CLEANUP_PHASE;
146 }
147 }
148
149 _LIBUNWIND_TRACE_UNWINDING("_GCC_specific_handler() calling personality "
150 "function %p(1, %d, %llx, %p, %p)",
151 (void *)pers, action, exc->exception_class,
152 (void *)exc, (void *)ctx);
153 urc = pers(1, action, exc->exception_class, exc, ctx);
154 _LIBUNWIND_TRACE_UNWINDING("_GCC_specific_handler() personality returned %d", urc);
155 switch (urc) {
156 case _URC_CONTINUE_UNWIND:
157 // If we're in phase 2, and the personality routine said to continue
158 // at the target frame, we're in real trouble.
159 if (action & _UA_HANDLER_FRAME)
160 _LIBUNWIND_ABORT("Personality continued unwind at the target frame!");
161 return ExceptionContinueSearch;
162 case _URC_HANDLER_FOUND:
163 // If we were called by __libunwind_seh_personality(), indicate that
164 // a handler was found; otherwise, initiate phase 2 by unwinding.
165 if (ours && ms_exc->NumberParameters > 1)
166 return 4 /* ExceptionExecuteHandler in mingw */;
167 // This should never happen in phase 2.
168 if (IS_UNWINDING(ms_exc->ExceptionFlags))
169 _LIBUNWIND_ABORT("Personality indicated exception handler in phase 2!");
170 exc->private_[1] = (ULONG_PTR)frame;
171 if (ours) {
172 ms_exc->NumberParameters = 4;
173 ms_exc->ExceptionInformation[1] = (ULONG_PTR)frame;
174 }
175 // FIXME: Indicate target frame in foreign case!
176 // phase 2: the clean up phase
177 RtlUnwindEx(frame, (PVOID)disp->ControlPc, ms_exc, exc, ms_ctx, disp->HistoryTable);
178 _LIBUNWIND_ABORT("RtlUnwindEx() failed");
179 case _URC_INSTALL_CONTEXT: {
180 // If we were called by __libunwind_seh_personality(), indicate that
181 // a handler was found; otherwise, it's time to initiate a collided
182 // unwind to the target.
183 if (ours && !IS_UNWINDING(ms_exc->ExceptionFlags) && ms_exc->NumberParameters > 1)
184 return 4 /* ExceptionExecuteHandler in mingw */;
185 // This should never happen in phase 1.
186 if (!IS_UNWINDING(ms_exc->ExceptionFlags))
187 _LIBUNWIND_ABORT("Personality installed context during phase 1!");
188#ifdef __x86_64__
189 exc->private_[2] = disp->TargetIp;
190 __unw_get_reg(&cursor, UNW_X86_64_RAX, &retval);
191 __unw_get_reg(&cursor, UNW_X86_64_RDX, &exc->private_[3]);
192#elif defined(__arm__)
193 exc->private_[2] = disp->TargetPc;
194 __unw_get_reg(&cursor, UNW_ARM_R0, &retval);
195 __unw_get_reg(&cursor, UNW_ARM_R1, &exc->private_[3]);
196#elif defined(__aarch64__)
197 exc->private_[2] = disp->TargetPc;
198 __unw_get_reg(&cursor, UNW_AARCH64_X0, &retval);
199 __unw_get_reg(&cursor, UNW_AARCH64_X1, &exc->private_[3]);
200#endif
201 __unw_get_reg(&cursor, UNW_REG_IP, &target);
202 ms_exc->ExceptionCode = STATUS_GCC_UNWIND;
203#ifdef __x86_64__
204 ms_exc->ExceptionInformation[2] = disp->TargetIp;
205#elif defined(__arm__) || defined(__aarch64__)
206 ms_exc->ExceptionInformation[2] = disp->TargetPc;
207#endif
208 ms_exc->ExceptionInformation[3] = exc->private_[3];
209 // Give NTRTL some scratch space to keep track of the collided unwind.
210 // Don't use the one that was passed in; we don't want to overwrite the
211 // context in the DISPATCHER_CONTEXT.
212 CONTEXT new_ctx;
213 RtlUnwindEx(frame, (PVOID)target, ms_exc, (PVOID)retval, &new_ctx, disp->HistoryTable);
214 _LIBUNWIND_ABORT("RtlUnwindEx() failed");
215 }
216 // Anything else indicates a serious problem.
217 default: return ExceptionContinueExecution;
218 }
219}
220
221/// Personality function returned by \c __unw_get_proc_info() in SEH contexts.
222/// This is a wrapper that calls the real SEH handler function, which in
223/// turn (at least, for Itanium-style frames) calls the real Itanium
224/// personality function (see \c _GCC_specific_handler()).
225extern "C" _Unwind_Reason_Code
226__libunwind_seh_personality(int version, _Unwind_Action state,
227 uint64_t klass, _Unwind_Exception *exc,
228 struct _Unwind_Context *context) {
229 (void)version;
230 (void)klass;
231 EXCEPTION_RECORD ms_exc;
232 bool phase2 = (state & (_UA_SEARCH_PHASE|_UA_CLEANUP_PHASE)) == _UA_CLEANUP_PHASE;
233 ms_exc.ExceptionCode = STATUS_GCC_THROW;
234 ms_exc.ExceptionFlags = 0;
235 ms_exc.NumberParameters = 3;
236 ms_exc.ExceptionInformation[0] = (ULONG_PTR)exc;
237 ms_exc.ExceptionInformation[1] = (ULONG_PTR)context;
238 ms_exc.ExceptionInformation[2] = state;
239 DISPATCHER_CONTEXT *disp_ctx =
240 __unw_seh_get_disp_ctx((unw_cursor_t *)context);
241#if defined(__aarch64__)
242 LOCAL_DISPATCHER_CONTEXT_NONVOLREG_ARM64 nonvol;
243 memcpy(&nonvol.GpNvRegs, &disp_ctx->ContextRecord->X19,
244 sizeof(nonvol.GpNvRegs));
245 for (int i = 0; i < 8; i++)
246 nonvol.FpNvRegs[i] = disp_ctx->ContextRecord->V[i + 8].D[0];
247 disp_ctx->NonVolatileRegisters = nonvol.Buffer;
248#elif defined(__arm__)
249 LOCAL_DISPATCHER_CONTEXT_NONVOLREG_ARM nonvol;
250 memcpy(&nonvol.GpNvRegs, &disp_ctx->ContextRecord->R4,
251 sizeof(nonvol.GpNvRegs));
252 memcpy(&nonvol.FpNvRegs, &disp_ctx->ContextRecord->D[8],
253 sizeof(nonvol.FpNvRegs));
254 disp_ctx->NonVolatileRegisters = nonvol.Buffer;
255#endif
256 _LIBUNWIND_TRACE_UNWINDING("__libunwind_seh_personality() calling "
257 "LanguageHandler %p(%p, %p, %p, %p)",
258 (void *)disp_ctx->LanguageHandler, (void *)&ms_exc,
259 (void *)disp_ctx->EstablisherFrame,
260 (void *)disp_ctx->ContextRecord, (void *)disp_ctx);
261 EXCEPTION_DISPOSITION ms_act = disp_ctx->LanguageHandler(&ms_exc,
262 (PVOID)disp_ctx->EstablisherFrame,
263 disp_ctx->ContextRecord,
264 disp_ctx);
265 _LIBUNWIND_TRACE_UNWINDING("__libunwind_seh_personality() LanguageHandler "
266 "returned %d",
267 (int)ms_act);
268 switch (ms_act) {
269 case ExceptionContinueExecution: return _URC_END_OF_STACK;
270 case ExceptionContinueSearch: return _URC_CONTINUE_UNWIND;
271 case 4 /*ExceptionExecuteHandler*/:
272 return phase2 ? _URC_INSTALL_CONTEXT : _URC_HANDLER_FOUND;
273 default:
274 return phase2 ? _URC_FATAL_PHASE2_ERROR : _URC_FATAL_PHASE1_ERROR;
275 }
276}
277
278static _Unwind_Reason_Code
279unwind_phase2_forced(unw_context_t *uc,
280 _Unwind_Exception *exception_object,
281 _Unwind_Stop_Fn stop, void *stop_parameter) {
282 unw_cursor_t cursor2;
283 __unw_init_local(&cursor2, uc);
284
285 // Walk each frame until we reach where search phase said to stop
286 while (__unw_step(&cursor2) > 0) {
287
288 // Update info about this frame.
289 unw_proc_info_t frameInfo;
290 if (__unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) {
291 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): __unw_get_proc_info "
292 "failed => _URC_END_OF_STACK",
293 (void *)exception_object);
294 return _URC_FATAL_PHASE2_ERROR;
295 }
296
297#ifndef NDEBUG
298 // When tracing, print state information.
299 if (_LIBUNWIND_TRACING_UNWINDING) {
300 char functionBuf[512];
301 const char *functionName = functionBuf;
302 unw_word_t offset;
303 if ((__unw_get_proc_name(&cursor2, functionBuf, sizeof(functionBuf),
304 &offset) != UNW_ESUCCESS) ||
305 (frameInfo.start_ip + offset > frameInfo.end_ip))
306 functionName = ".anonymous.";
307 _LIBUNWIND_TRACE_UNWINDING(
308 "unwind_phase2_forced(ex_ojb=%p): start_ip=0x%" PRIxPTR
309 ", func=%s, lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR,
310 (void *)exception_object, frameInfo.start_ip, functionName,
311 frameInfo.lsda, frameInfo.handler);
312 }
313#endif
314
315 // Call stop function at each frame.
316 _Unwind_Action action =
317 (_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE);
318 _Unwind_Reason_Code stopResult =
319 (*stop)(1, action, exception_object->exception_class, exception_object,
320 (struct _Unwind_Context *)(&cursor2), stop_parameter);
321 _LIBUNWIND_TRACE_UNWINDING(
322 "unwind_phase2_forced(ex_ojb=%p): stop function returned %d",
323 (void *)exception_object, stopResult);
324 if (stopResult != _URC_NO_REASON) {
325 _LIBUNWIND_TRACE_UNWINDING(
326 "unwind_phase2_forced(ex_ojb=%p): stopped by stop function",
327 (void *)exception_object);
328 return _URC_FATAL_PHASE2_ERROR;
329 }
330
331 // If there is a personality routine, tell it we are unwinding.
332 if (frameInfo.handler != 0) {
333 _Unwind_Personality_Fn p =
334 (_Unwind_Personality_Fn)(intptr_t)(frameInfo.handler);
335 _LIBUNWIND_TRACE_UNWINDING(
336 "unwind_phase2_forced(ex_ojb=%p): calling personality function %p",
337 (void *)exception_object, (void *)(uintptr_t)p);
338 _Unwind_Reason_Code personalityResult =
339 (*p)(1, action, exception_object->exception_class, exception_object,
340 (struct _Unwind_Context *)(&cursor2));
341 switch (personalityResult) {
342 case _URC_CONTINUE_UNWIND:
343 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
344 "personality returned "
345 "_URC_CONTINUE_UNWIND",
346 (void *)exception_object);
347 // Destructors called, continue unwinding
348 break;
349 case _URC_INSTALL_CONTEXT:
350 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
351 "personality returned "
352 "_URC_INSTALL_CONTEXT",
353 (void *)exception_object);
354 // We may get control back if landing pad calls _Unwind_Resume().
355 __unw_resume(&cursor2);
356 break;
357 case _URC_END_OF_STACK:
358 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
359 "personality returned "
360 "_URC_END_OF_STACK",
361 (void *)exception_object);
362 break;
363 default:
364 // Personality routine returned an unknown result code.
365 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
366 "personality returned %d, "
367 "_URC_FATAL_PHASE2_ERROR",
368 (void *)exception_object, personalityResult);
369 return _URC_FATAL_PHASE2_ERROR;
370 }
371 if (personalityResult == _URC_END_OF_STACK)
372 break;
373 }
374 }
375
376 // Call stop function one last time and tell it we've reached the end
377 // of the stack.
378 _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): calling stop "
379 "function with _UA_END_OF_STACK",
380 (void *)exception_object);
381 _Unwind_Action lastAction =
382 (_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE | _UA_END_OF_STACK);
383 (*stop)(1, lastAction, exception_object->exception_class, exception_object,
384 (struct _Unwind_Context *)(&cursor2), stop_parameter);
385
386 // Clean up phase did not resume at the frame that the search phase said it
387 // would.
388 return _URC_FATAL_PHASE2_ERROR;
389}
390
391/// Called by \c __cxa_throw(). Only returns if there is a fatal error.
392_LIBUNWIND_EXPORT _Unwind_Reason_Code
393_Unwind_RaiseException(_Unwind_Exception *exception_object) {
394 _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)",
395 (void *)exception_object);
396
397 // Mark that this is a non-forced unwind, so _Unwind_Resume()
398 // can do the right thing.
399 memset(exception_object->private_, 0, sizeof(exception_object->private_));
400
401 // phase 1: the search phase
402 // We'll let the system do that for us.
403 RaiseException(STATUS_GCC_THROW, 0, 1, (ULONG_PTR *)&exception_object);
404
405 // If we get here, either something went horribly wrong or we reached the
406 // top of the stack. Either way, let libc++abi call std::terminate().
407 return _URC_END_OF_STACK;
408}
409
410/// When \c _Unwind_RaiseException() is in phase2, it hands control
411/// to the personality function at each frame. The personality
412/// may force a jump to a landing pad in that function; the landing
413/// pad code may then call \c _Unwind_Resume() to continue with the
414/// unwinding. Note: the call to \c _Unwind_Resume() is from compiler
415/// generated user code. All other \c _Unwind_* routines are called
416/// by the C++ runtime \c __cxa_* routines.
417///
418/// Note: re-throwing an exception (as opposed to continuing the unwind)
419/// is implemented by having the code call \c __cxa_rethrow() which
420/// in turn calls \c _Unwind_Resume_or_Rethrow().
421_LIBUNWIND_EXPORT void
422_Unwind_Resume(_Unwind_Exception *exception_object) {
423 _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)", (void *)exception_object);
424
425 if (exception_object->private_[0] != 0) {
426 unw_context_t uc;
427
428 __unw_getcontext(&uc);
429 unwind_phase2_forced(&uc, exception_object,
430 (_Unwind_Stop_Fn) exception_object->private_[0],
431 (void *)exception_object->private_[4]);
432 } else {
433 // Recover the parameters for the unwind from the exception object
434 // so we can start unwinding again.
435 EXCEPTION_RECORD ms_exc;
436 CONTEXT ms_ctx;
437 UNWIND_HISTORY_TABLE hist;
438
439 memset(&ms_exc, 0, sizeof(ms_exc));
440 memset(&hist, 0, sizeof(hist));
441 ms_exc.ExceptionCode = STATUS_GCC_THROW;
442 ms_exc.ExceptionFlags = EXCEPTION_NONCONTINUABLE;
443 ms_exc.NumberParameters = 4;
444 ms_exc.ExceptionInformation[0] = (ULONG_PTR)exception_object;
445 ms_exc.ExceptionInformation[1] = exception_object->private_[1];
446 ms_exc.ExceptionInformation[2] = exception_object->private_[2];
447 ms_exc.ExceptionInformation[3] = exception_object->private_[3];
448 RtlUnwindEx((PVOID)exception_object->private_[1],
449 (PVOID)exception_object->private_[2], &ms_exc,
450 exception_object, &ms_ctx, &hist);
451 }
452
453 // Clients assume _Unwind_Resume() does not return, so all we can do is abort.
454 _LIBUNWIND_ABORT("_Unwind_Resume() can't return");
455}
456
457/// Not used by C++.
458/// Unwinds stack, calling "stop" function at each frame.
459/// Could be used to implement \c longjmp().
460_LIBUNWIND_EXPORT _Unwind_Reason_Code
461_Unwind_ForcedUnwind(_Unwind_Exception *exception_object,
462 _Unwind_Stop_Fn stop, void *stop_parameter) {
463 _LIBUNWIND_TRACE_API("_Unwind_ForcedUnwind(ex_obj=%p, stop=%p)",
464 (void *)exception_object, (void *)(uintptr_t)stop);
465 unw_context_t uc;
466 __unw_getcontext(&uc);
467
468 // Mark that this is a forced unwind, so _Unwind_Resume() can do
469 // the right thing.
470 exception_object->private_[0] = (uintptr_t) stop;
471 exception_object->private_[4] = (uintptr_t) stop_parameter;
472
473 // do it
474 return unwind_phase2_forced(&uc, exception_object, stop, stop_parameter);
475}
476
477/// Called by personality handler during phase 2 to get LSDA for current frame.
478_LIBUNWIND_EXPORT uintptr_t
479_Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) {
480 uintptr_t result =
481 (uintptr_t)__unw_seh_get_disp_ctx((unw_cursor_t *)context)->HandlerData;
482 _LIBUNWIND_TRACE_API(
483 "_Unwind_GetLanguageSpecificData(context=%p) => 0x%" PRIxPTR,
484 (void *)context, result);
485 return result;
486}
487
488/// Called by personality handler during phase 2 to find the start of the
489/// function.
490_LIBUNWIND_EXPORT uintptr_t
491_Unwind_GetRegionStart(struct _Unwind_Context *context) {
492 DISPATCHER_CONTEXT *disp = __unw_seh_get_disp_ctx((unw_cursor_t *)context);
493 uintptr_t result = (uintptr_t)disp->FunctionEntry->BeginAddress + disp->ImageBase;
494 _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%" PRIxPTR,
495 (void *)context, result);
496 return result;
497}
498
499static int __unw_init_seh(unw_cursor_t *cursor, CONTEXT *context) {
500#ifdef _LIBUNWIND_TARGET_X86_64
501 new (reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_x86_64> *>(cursor))
502 UnwindCursor<LocalAddressSpace, Registers_x86_64>(
503 context, LocalAddressSpace::sThisAddressSpace);
504 auto *co = reinterpret_cast<AbstractUnwindCursor *>(cursor);
505 co->setInfoBasedOnIPRegister();
506 return UNW_ESUCCESS;
507#elif defined(_LIBUNWIND_TARGET_ARM)
508 new (reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_arm> *>(cursor))
509 UnwindCursor<LocalAddressSpace, Registers_arm>(
510 context, LocalAddressSpace::sThisAddressSpace);
511 auto *co = reinterpret_cast<AbstractUnwindCursor *>(cursor);
512 co->setInfoBasedOnIPRegister();
513 return UNW_ESUCCESS;
514#elif defined(_LIBUNWIND_TARGET_AARCH64)
515 new (reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_arm64> *>(cursor))
516 UnwindCursor<LocalAddressSpace, Registers_arm64>(
517 context, LocalAddressSpace::sThisAddressSpace);
518 auto *co = reinterpret_cast<AbstractUnwindCursor *>(cursor);
519 co->setInfoBasedOnIPRegister();
520 return UNW_ESUCCESS;
521#else
522 return UNW_EINVAL;
523#endif
524}
525
526static DISPATCHER_CONTEXT *__unw_seh_get_disp_ctx(unw_cursor_t *cursor) {
527#ifdef _LIBUNWIND_TARGET_X86_64
528 return reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_x86_64> *>(cursor)->getDispatcherContext();
529#elif defined(_LIBUNWIND_TARGET_ARM)
530 return reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_arm> *>(cursor)->getDispatcherContext();
531#elif defined(_LIBUNWIND_TARGET_AARCH64)
532 return reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_arm64> *>(cursor)->getDispatcherContext();
533#else
534 return nullptr;
535#endif
536}
537
538static void __unw_seh_set_disp_ctx(unw_cursor_t *cursor,
539 DISPATCHER_CONTEXT *disp) {
540#ifdef _LIBUNWIND_TARGET_X86_64
541 reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_x86_64> *>(cursor)->setDispatcherContext(disp);
542#elif defined(_LIBUNWIND_TARGET_ARM)
543 reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_arm> *>(cursor)->setDispatcherContext(disp);
544#elif defined(_LIBUNWIND_TARGET_AARCH64)
545 reinterpret_cast<UnwindCursor<LocalAddressSpace, Registers_arm64> *>(cursor)->setDispatcherContext(disp);
546#endif
547}
548
549#endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
550