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	// C++ interface to lower levels of libunwind
9	//===----------------------------------------------------------------------===//
10
11	#ifndef __UNWINDCURSOR_HPP__
12	#define __UNWINDCURSOR_HPP__
13
14	#include "shadow_stack_unwind.h"
15	#include <stdint.h>
16	#include <stdio.h>
17	#include <stdlib.h>
18	#include <unwind.h>
19
20	#ifdef _WIN32
21	#include <windows.h>
22	#include <ntverp.h>
23	#endif
24	#ifdef __APPLE__
25	#include <mach-o/dyld.h>
26	#endif
27	#ifdef _AIX
28	#include <dlfcn.h>
29	#include <sys/debug.h>
30	#include <sys/pseg.h>
31	#endif
32
33	#if defined(_LIBUNWIND_TARGET_LINUX) && \
34	(defined(_LIBUNWIND_TARGET_AARCH64) || \
35	defined(_LIBUNWIND_TARGET_LOONGARCH) || \
36	defined(_LIBUNWIND_TARGET_RISCV) || defined(_LIBUNWIND_TARGET_S390X))
37	#include <errno.h>
38	#include <signal.h>
39	#include <sys/syscall.h>
40	#include <unistd.h>
41	#define _LIBUNWIND_CHECK_LINUX_SIGRETURN 1
42	#endif
43
44	#if defined(_LIBUNWIND_TARGET_HAIKU) && defined(_LIBUNWIND_TARGET_X86_64)
45	#include <OS.h>
46	#include <signal.h>
47	#define _LIBUNWIND_CHECK_HAIKU_SIGRETURN 1
48	#endif
49
50	#include "AddressSpace.hpp"
51	#include "CompactUnwinder.hpp"
52	#include "config.h"
53	#include "DwarfInstructions.hpp"
54	#include "EHHeaderParser.hpp"
55	#include "libunwind.h"
56	#include "libunwind_ext.h"
57	#include "Registers.hpp"
58	#include "RWMutex.hpp"
59	#include "Unwind-EHABI.h"
60
61	#if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
62	// Provide a definition for the DISPATCHER_CONTEXT struct for old (Win7 and
63	// earlier) SDKs.
64	// MinGW-w64 has always provided this struct.
65	#if defined(_WIN32) && defined(_LIBUNWIND_TARGET_X86_64) && \
66	!defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
67	struct _DISPATCHER_CONTEXT {
68	ULONG64 ControlPc;
69	ULONG64 ImageBase;
70	PRUNTIME_FUNCTION FunctionEntry;
71	ULONG64 EstablisherFrame;
72	ULONG64 TargetIp;
73	PCONTEXT ContextRecord;
74	PEXCEPTION_ROUTINE LanguageHandler;
75	PVOID HandlerData;
76	PUNWIND_HISTORY_TABLE HistoryTable;
77	ULONG ScopeIndex;
78	ULONG Fill0;
79	};
80	#endif
81
82	struct UNWIND_INFO {
83	uint8_t Version : 3;
84	uint8_t Flags : 5;
85	uint8_t SizeOfProlog;
86	uint8_t CountOfCodes;
87	uint8_t FrameRegister : 4;
88	uint8_t FrameOffset : 4;
89	uint16_t UnwindCodes[2];
90	};
91
92	#pragma clang diagnostic push
93	#pragma clang diagnostic ignored "-Wgnu-anonymous-struct"
94	union UNWIND_INFO_ARM {
95	DWORD HeaderData;
96	struct {
97	DWORD FunctionLength : 18;
98	DWORD Version : 2;
99	DWORD ExceptionDataPresent : 1;
100	DWORD EpilogInHeader : 1;
101	DWORD FunctionFragment : 1;
102	DWORD EpilogCount : 5;
103	DWORD CodeWords : 4;
104	};
105	};
106	#pragma clang diagnostic pop
107
108	extern "C" _Unwind_Reason_Code __libunwind_seh_personality(
109	int, _Unwind_Action, uint64_t, _Unwind_Exception *,
110	struct _Unwind_Context *);
111
112	#endif
113
114	namespace libunwind {
115
116	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
117	/// Cache of recently found FDEs.
118	template <typename A>
119	class _LIBUNWIND_HIDDEN DwarfFDECache {
120	typedef typename A::pint_t pint_t;
121	public:
122	static constexpr pint_t kSearchAll = static_cast<pint_t>(-1);
123	static pint_t findFDE(pint_t mh, pint_t pc);
124	static void add(pint_t mh, pint_t ip_start, pint_t ip_end, pint_t fde);
125	static void removeAllIn(pint_t mh);
126	static void iterateCacheEntries(void (*func)(unw_word_t ip_start,
127	unw_word_t ip_end,
128	unw_word_t fde, unw_word_t mh));
129
130	private:
131
132	struct entry {
133	pint_t mh;
134	pint_t ip_start;
135	pint_t ip_end;
136	pint_t fde;
137	};
138
139	// These fields are all static to avoid needing an initializer.
140	// There is only one instance of this class per process.
141	static RWMutex _lock;
142	#ifdef __APPLE__
143	static void dyldUnloadHook(const struct mach_header *mh, intptr_t slide);
144	static bool _registeredForDyldUnloads;
145	#endif
146	static entry *_buffer;
147	static entry *_bufferUsed;
148	static entry *_bufferEnd;
149	static entry _initialBuffer[64];
150	};
151
152	template <typename A>
153	typename DwarfFDECache<A>::entry *
154	DwarfFDECache<A>::_buffer = _initialBuffer;
155
156	template <typename A>
157	typename DwarfFDECache<A>::entry *
158	DwarfFDECache<A>::_bufferUsed = _initialBuffer;
159
160	template <typename A>
161	typename DwarfFDECache<A>::entry *
162	DwarfFDECache<A>::_bufferEnd = &_initialBuffer[64];
163
164	template <typename A>
165	typename DwarfFDECache<A>::entry DwarfFDECache<A>::_initialBuffer[64];
166
167	template <typename A>
168	RWMutex DwarfFDECache<A>::_lock;
169
170	#ifdef __APPLE__
171	template <typename A>
172	bool DwarfFDECache<A>::_registeredForDyldUnloads = false;
173	#endif
174
175	template <typename A>
176	typename DwarfFDECache<A>::pint_t DwarfFDECache<A>::findFDE(pint_t mh,
177	pint_t pc) {
178	pint_t result = 0;
179	_LIBUNWIND_LOG_IF_FALSE(_lock.lock_shared());
180	for (entry *p = _buffer; p < _bufferUsed; ++p) {
181	if ((mh == p->mh) || (mh == kSearchAll)) {
182	if ((p->ip_start <= pc) && (pc < p->ip_end)) {
183	result = p->fde;
184	break;
185	}
186	}
187	}
188	_LIBUNWIND_LOG_IF_FALSE(_lock.unlock_shared());
189	return result;
190	}
191
192	template <typename A>
193	void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
194	pint_t fde) {
195	#if !defined(_LIBUNWIND_NO_HEAP)
196	_LIBUNWIND_LOG_IF_FALSE(_lock.lock());
197	if (_bufferUsed >= _bufferEnd) {
198	size_t oldSize = (size_t)(_bufferEnd - _buffer);
199	size_t newSize = oldSize * 4;
200	// Can't use operator new (we are below it).
201	entry *newBuffer = (entry *)malloc(size: newSize * sizeof(entry));
202	memcpy(newBuffer, _buffer, oldSize * sizeof(entry));
203	if (_buffer != _initialBuffer)
204	free(_buffer);
205	_buffer = newBuffer;
206	_bufferUsed = &newBuffer[oldSize];
207	_bufferEnd = &newBuffer[newSize];
208	}
209	_bufferUsed->mh = mh;
210	_bufferUsed->ip_start = ip_start;
211	_bufferUsed->ip_end = ip_end;
212	_bufferUsed->fde = fde;
213	++_bufferUsed;
214	#ifdef __APPLE__
215	if (!_registeredForDyldUnloads) {
216	_dyld_register_func_for_remove_image(&dyldUnloadHook);
217	_registeredForDyldUnloads = true;
218	}
219	#endif
220	_LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
221	#endif
222	}
223
224	template <typename A>
225	void DwarfFDECache<A>::removeAllIn(pint_t mh) {
226	_LIBUNWIND_LOG_IF_FALSE(_lock.lock());
227	entry *d = _buffer;
228	for (const entry *s = _buffer; s < _bufferUsed; ++s) {
229	if (s->mh != mh) {
230	if (d != s)
231	*d = *s;
232	++d;
233	}
234	}
235	_bufferUsed = d;
236	_LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
237	}
238
239	#ifdef __APPLE__
240	template <typename A>
241	void DwarfFDECache<A>::dyldUnloadHook(const struct mach_header *mh, intptr_t ) {
242	removeAllIn((pint_t) mh);
243	}
244	#endif
245
246	template <typename A>
247	void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
248	unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
249	_LIBUNWIND_LOG_IF_FALSE(_lock.lock());
250	for (entry *p = _buffer; p < _bufferUsed; ++p) {
251	(*func)(p->ip_start, p->ip_end, p->fde, p->mh);
252	}
253	_LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
254	}
255	#endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
256
257	#define arrayoffsetof(type, index, field) \
258	(sizeof(type) * (index) + offsetof(type, field))
259
260	#if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
261	template <typename A> class UnwindSectionHeader {
262	public:
263	UnwindSectionHeader(A &addressSpace, typename A::pint_t addr)
264	: _addressSpace(addressSpace), _addr(addr) {}
265
266	uint32_t version() const {
267	return _addressSpace.get32(_addr +
268	offsetof(unwind_info_section_header, version));
269	}
270	uint32_t commonEncodingsArraySectionOffset() const {
271	return _addressSpace.get32(_addr +
272	offsetof(unwind_info_section_header,
273	commonEncodingsArraySectionOffset));
274	}
275	uint32_t commonEncodingsArrayCount() const {
276	return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
277	commonEncodingsArrayCount));
278	}
279	uint32_t personalityArraySectionOffset() const {
280	return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
281	personalityArraySectionOffset));
282	}
283	uint32_t personalityArrayCount() const {
284	return _addressSpace.get32(
285	_addr + offsetof(unwind_info_section_header, personalityArrayCount));
286	}
287	uint32_t indexSectionOffset() const {
288	return _addressSpace.get32(
289	_addr + offsetof(unwind_info_section_header, indexSectionOffset));
290	}
291	uint32_t indexCount() const {
292	return _addressSpace.get32(
293	_addr + offsetof(unwind_info_section_header, indexCount));
294	}
295
296	private:
297	A &_addressSpace;
298	typename A::pint_t _addr;
299	};
300
301	template <typename A> class UnwindSectionIndexArray {
302	public:
303	UnwindSectionIndexArray(A &addressSpace, typename A::pint_t addr)
304	: _addressSpace(addressSpace), _addr(addr) {}
305
306	uint32_t functionOffset(uint32_t index) const {
307	return _addressSpace.get32(
308	_addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
309	functionOffset));
310	}
311	uint32_t secondLevelPagesSectionOffset(uint32_t index) const {
312	return _addressSpace.get32(
313	_addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
314	secondLevelPagesSectionOffset));
315	}
316	uint32_t lsdaIndexArraySectionOffset(uint32_t index) const {
317	return _addressSpace.get32(
318	_addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
319	lsdaIndexArraySectionOffset));
320	}
321
322	private:
323	A &_addressSpace;
324	typename A::pint_t _addr;
325	};
326
327	template <typename A> class UnwindSectionRegularPageHeader {
328	public:
329	UnwindSectionRegularPageHeader(A &addressSpace, typename A::pint_t addr)
330	: _addressSpace(addressSpace), _addr(addr) {}
331
332	uint32_t kind() const {
333	return _addressSpace.get32(
334	_addr + offsetof(unwind_info_regular_second_level_page_header, kind));
335	}
336	uint16_t entryPageOffset() const {
337	return _addressSpace.get16(
338	_addr + offsetof(unwind_info_regular_second_level_page_header,
339	entryPageOffset));
340	}
341	uint16_t entryCount() const {
342	return _addressSpace.get16(
343	_addr +
344	offsetof(unwind_info_regular_second_level_page_header, entryCount));
345	}
346
347	private:
348	A &_addressSpace;
349	typename A::pint_t _addr;
350	};
351
352	template <typename A> class UnwindSectionRegularArray {
353	public:
354	UnwindSectionRegularArray(A &addressSpace, typename A::pint_t addr)
355	: _addressSpace(addressSpace), _addr(addr) {}
356
357	uint32_t functionOffset(uint32_t index) const {
358	return _addressSpace.get32(
359	_addr + arrayoffsetof(unwind_info_regular_second_level_entry, index,
360	functionOffset));
361	}
362	uint32_t encoding(uint32_t index) const {
363	return _addressSpace.get32(
364	_addr +
365	arrayoffsetof(unwind_info_regular_second_level_entry, index, encoding));
366	}
367
368	private:
369	A &_addressSpace;
370	typename A::pint_t _addr;
371	};
372
373	template <typename A> class UnwindSectionCompressedPageHeader {
374	public:
375	UnwindSectionCompressedPageHeader(A &addressSpace, typename A::pint_t addr)
376	: _addressSpace(addressSpace), _addr(addr) {}
377
378	uint32_t kind() const {
379	return _addressSpace.get32(
380	_addr +
381	offsetof(unwind_info_compressed_second_level_page_header, kind));
382	}
383	uint16_t entryPageOffset() const {
384	return _addressSpace.get16(
385	_addr + offsetof(unwind_info_compressed_second_level_page_header,
386	entryPageOffset));
387	}
388	uint16_t entryCount() const {
389	return _addressSpace.get16(
390	_addr +
391	offsetof(unwind_info_compressed_second_level_page_header, entryCount));
392	}
393	uint16_t encodingsPageOffset() const {
394	return _addressSpace.get16(
395	_addr + offsetof(unwind_info_compressed_second_level_page_header,
396	encodingsPageOffset));
397	}
398	uint16_t encodingsCount() const {
399	return _addressSpace.get16(
400	_addr + offsetof(unwind_info_compressed_second_level_page_header,
401	encodingsCount));
402	}
403
404	private:
405	A &_addressSpace;
406	typename A::pint_t _addr;
407	};
408
409	template <typename A> class UnwindSectionCompressedArray {
410	public:
411	UnwindSectionCompressedArray(A &addressSpace, typename A::pint_t addr)
412	: _addressSpace(addressSpace), _addr(addr) {}
413
414	uint32_t functionOffset(uint32_t index) const {
415	return UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(
416	_addressSpace.get32(_addr + index * sizeof(uint32_t)));
417	}
418	uint16_t encodingIndex(uint32_t index) const {
419	return UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(
420	_addressSpace.get32(_addr + index * sizeof(uint32_t)));
421	}
422
423	private:
424	A &_addressSpace;
425	typename A::pint_t _addr;
426	};
427
428	template <typename A> class UnwindSectionLsdaArray {
429	public:
430	UnwindSectionLsdaArray(A &addressSpace, typename A::pint_t addr)
431	: _addressSpace(addressSpace), _addr(addr) {}
432
433	uint32_t functionOffset(uint32_t index) const {
434	return _addressSpace.get32(
435	_addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
436	index, functionOffset));
437	}
438	uint32_t lsdaOffset(uint32_t index) const {
439	return _addressSpace.get32(
440	_addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
441	index, lsdaOffset));
442	}
443
444	private:
445	A &_addressSpace;
446	typename A::pint_t _addr;
447	};
448	#endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
449
450	class _LIBUNWIND_HIDDEN AbstractUnwindCursor {
451	public:
452	// NOTE: provide a class specific placement deallocation function (S5.3.4 p20)
453	// This avoids an unnecessary dependency to libc++abi.
454	void operator delete(void *, size_t) {}
455
456	virtual ~AbstractUnwindCursor() {}
457	virtual bool validReg(int) { _LIBUNWIND_ABORT("validReg not implemented"); }
458	virtual unw_word_t getReg(int) { _LIBUNWIND_ABORT("getReg not implemented"); }
459	virtual void setReg(int, unw_word_t) {
460	_LIBUNWIND_ABORT("setReg not implemented");
461	}
462	virtual bool validFloatReg(int) {
463	_LIBUNWIND_ABORT("validFloatReg not implemented");
464	}
465	virtual unw_fpreg_t getFloatReg(int) {
466	_LIBUNWIND_ABORT("getFloatReg not implemented");
467	}
468	virtual void setFloatReg(int, unw_fpreg_t) {
469	_LIBUNWIND_ABORT("setFloatReg not implemented");
470	}
471	virtual int step(bool = false) { _LIBUNWIND_ABORT("step not implemented"); }
472	virtual void getInfo(unw_proc_info_t *) {
473	_LIBUNWIND_ABORT("getInfo not implemented");
474	}
475	virtual void jumpto() { _LIBUNWIND_ABORT("jumpto not implemented"); }
476	virtual bool isSignalFrame() {
477	_LIBUNWIND_ABORT("isSignalFrame not implemented");
478	}
479	virtual bool getFunctionName(char *, size_t, unw_word_t *) {
480	_LIBUNWIND_ABORT("getFunctionName not implemented");
481	}
482	virtual void setInfoBasedOnIPRegister(bool = false) {
483	_LIBUNWIND_ABORT("setInfoBasedOnIPRegister not implemented");
484	}
485	virtual const char *getRegisterName(int) {
486	_LIBUNWIND_ABORT("getRegisterName not implemented");
487	}
488	#ifdef __arm__
489	virtual void saveVFPAsX() { _LIBUNWIND_ABORT("saveVFPAsX not implemented"); }
490	#endif
491
492	#ifdef _AIX
493	virtual uintptr_t getDataRelBase() {
494	_LIBUNWIND_ABORT("getDataRelBase not implemented");
495	}
496	#endif
497
498	#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
499	virtual void *get_registers() {
500	_LIBUNWIND_ABORT("get_registers not implemented");
501	}
502	#endif
503	};
504
505	#if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)
506
507	/// \c UnwindCursor contains all state (including all register values) during
508	/// an unwind. This is normally stack-allocated inside a unw_cursor_t.
509	template <typename A, typename R>
510	class UnwindCursor : public AbstractUnwindCursor {
511	typedef typename A::pint_t pint_t;
512	public:
513	UnwindCursor(unw_context_t *context, A &as);
514	UnwindCursor(CONTEXT *context, A &as);
515	UnwindCursor(A &as, void *threadArg);
516	virtual ~UnwindCursor() {}
517	virtual bool validReg(int);
518	virtual unw_word_t getReg(int);
519	virtual void setReg(int, unw_word_t);
520	virtual bool validFloatReg(int);
521	virtual unw_fpreg_t getFloatReg(int);
522	virtual void setFloatReg(int, unw_fpreg_t);
523	virtual int step(bool = false);
524	virtual void getInfo(unw_proc_info_t *);
525	virtual void jumpto();
526	virtual bool isSignalFrame();
527	virtual bool getFunctionName(char *buf, size_t len, unw_word_t *off);
528	virtual void setInfoBasedOnIPRegister(bool isReturnAddress = false);
529	virtual const char *getRegisterName(int num);
530	#ifdef __arm__
531	virtual void saveVFPAsX();
532	#endif
533
534	DISPATCHER_CONTEXT *getDispatcherContext() { return &_dispContext; }
535	void setDispatcherContext(DISPATCHER_CONTEXT *disp) {
536	_dispContext = *disp;
537	_info.lsda = reinterpret_cast<unw_word_t>(_dispContext.HandlerData);
538	if (_dispContext.LanguageHandler) {
539	_info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
540	} else
541	_info.handler = 0;
542	}
543
544	// libunwind does not and should not depend on C++ library which means that we
545	// need our own definition of inline placement new.
546	static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
547
548	private:
549
550	pint_t getLastPC() const { return _dispContext.ControlPc; }
551	void setLastPC(pint_t pc) { _dispContext.ControlPc = pc; }
552	RUNTIME_FUNCTION *lookUpSEHUnwindInfo(pint_t pc, pint_t *base) {
553	#ifdef __arm__
554	// Remove the thumb bit; FunctionEntry ranges don't include the thumb bit.
555	pc &= ~1U;
556	#endif
557	// If pc points exactly at the end of the range, we might resolve the
558	// next function instead. Decrement pc by 1 to fit inside the current
559	// function.
560	pc -= 1;
561	_dispContext.FunctionEntry = RtlLookupFunctionEntry(pc,
562	&_dispContext.ImageBase,
563	_dispContext.HistoryTable);
564	*base = _dispContext.ImageBase;
565	return _dispContext.FunctionEntry;
566	}
567	bool getInfoFromSEH(pint_t pc);
568	int stepWithSEHData() {
569	_dispContext.LanguageHandler = RtlVirtualUnwind(UNW_FLAG_UHANDLER,
570	_dispContext.ImageBase,
571	_dispContext.ControlPc,
572	_dispContext.FunctionEntry,
573	_dispContext.ContextRecord,
574	&_dispContext.HandlerData,
575	&_dispContext.EstablisherFrame,
576	NULL);
577	// Update some fields of the unwind info now, since we have them.
578	_info.lsda = reinterpret_cast<unw_word_t>(_dispContext.HandlerData);
579	if (_dispContext.LanguageHandler) {
580	_info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
581	} else
582	_info.handler = 0;
583	return UNW_STEP_SUCCESS;
584	}
585
586	A &_addressSpace;
587	unw_proc_info_t _info;
588	DISPATCHER_CONTEXT _dispContext;
589	CONTEXT _msContext;
590	UNWIND_HISTORY_TABLE _histTable;
591	bool _unwindInfoMissing;
592	};
593
594
595	template <typename A, typename R>
596	UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
597	: _addressSpace(as), _unwindInfoMissing(false) {
598	static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
599	"UnwindCursor<> does not fit in unw_cursor_t");
600	static_assert((alignof(UnwindCursor<A, R>) <= alignof(unw_cursor_t)),
601	"UnwindCursor<> requires more alignment than unw_cursor_t");
602	memset(&_info, 0, sizeof(_info));
603	memset(&_histTable, 0, sizeof(_histTable));
604	memset(&_dispContext, 0, sizeof(_dispContext));
605	_dispContext.ContextRecord = &_msContext;
606	_dispContext.HistoryTable = &_histTable;
607	// Initialize MS context from ours.
608	R r(context);
609	RtlCaptureContext(&_msContext);
610	_msContext.ContextFlags = CONTEXT_CONTROL|CONTEXT_INTEGER|CONTEXT_FLOATING_POINT;
611	#if defined(_LIBUNWIND_TARGET_X86_64)
612	_msContext.Rax = r.getRegister(UNW_X86_64_RAX);
613	_msContext.Rcx = r.getRegister(UNW_X86_64_RCX);
614	_msContext.Rdx = r.getRegister(UNW_X86_64_RDX);
615	_msContext.Rbx = r.getRegister(UNW_X86_64_RBX);
616	_msContext.Rsp = r.getRegister(UNW_X86_64_RSP);
617	_msContext.Rbp = r.getRegister(UNW_X86_64_RBP);
618	_msContext.Rsi = r.getRegister(UNW_X86_64_RSI);
619	_msContext.Rdi = r.getRegister(UNW_X86_64_RDI);
620	_msContext.R8 = r.getRegister(UNW_X86_64_R8);
621	_msContext.R9 = r.getRegister(UNW_X86_64_R9);
622	_msContext.R10 = r.getRegister(UNW_X86_64_R10);
623	_msContext.R11 = r.getRegister(UNW_X86_64_R11);
624	_msContext.R12 = r.getRegister(UNW_X86_64_R12);
625	_msContext.R13 = r.getRegister(UNW_X86_64_R13);
626	_msContext.R14 = r.getRegister(UNW_X86_64_R14);
627	_msContext.R15 = r.getRegister(UNW_X86_64_R15);
628	_msContext.Rip = r.getRegister(UNW_REG_IP);
629	union {
630	v128 v;
631	M128A m;
632	} t;
633	t.v = r.getVectorRegister(UNW_X86_64_XMM0);
634	_msContext.Xmm0 = t.m;
635	t.v = r.getVectorRegister(UNW_X86_64_XMM1);
636	_msContext.Xmm1 = t.m;
637	t.v = r.getVectorRegister(UNW_X86_64_XMM2);
638	_msContext.Xmm2 = t.m;
639	t.v = r.getVectorRegister(UNW_X86_64_XMM3);
640	_msContext.Xmm3 = t.m;
641	t.v = r.getVectorRegister(UNW_X86_64_XMM4);
642	_msContext.Xmm4 = t.m;
643	t.v = r.getVectorRegister(UNW_X86_64_XMM5);
644	_msContext.Xmm5 = t.m;
645	t.v = r.getVectorRegister(UNW_X86_64_XMM6);
646	_msContext.Xmm6 = t.m;
647	t.v = r.getVectorRegister(UNW_X86_64_XMM7);
648	_msContext.Xmm7 = t.m;
649	t.v = r.getVectorRegister(UNW_X86_64_XMM8);
650	_msContext.Xmm8 = t.m;
651	t.v = r.getVectorRegister(UNW_X86_64_XMM9);
652	_msContext.Xmm9 = t.m;
653	t.v = r.getVectorRegister(UNW_X86_64_XMM10);
654	_msContext.Xmm10 = t.m;
655	t.v = r.getVectorRegister(UNW_X86_64_XMM11);
656	_msContext.Xmm11 = t.m;
657	t.v = r.getVectorRegister(UNW_X86_64_XMM12);
658	_msContext.Xmm12 = t.m;
659	t.v = r.getVectorRegister(UNW_X86_64_XMM13);
660	_msContext.Xmm13 = t.m;
661	t.v = r.getVectorRegister(UNW_X86_64_XMM14);
662	_msContext.Xmm14 = t.m;
663	t.v = r.getVectorRegister(UNW_X86_64_XMM15);
664	_msContext.Xmm15 = t.m;
665	#elif defined(_LIBUNWIND_TARGET_ARM)
666	_msContext.R0 = r.getRegister(UNW_ARM_R0);
667	_msContext.R1 = r.getRegister(UNW_ARM_R1);
668	_msContext.R2 = r.getRegister(UNW_ARM_R2);
669	_msContext.R3 = r.getRegister(UNW_ARM_R3);
670	_msContext.R4 = r.getRegister(UNW_ARM_R4);
671	_msContext.R5 = r.getRegister(UNW_ARM_R5);
672	_msContext.R6 = r.getRegister(UNW_ARM_R6);
673	_msContext.R7 = r.getRegister(UNW_ARM_R7);
674	_msContext.R8 = r.getRegister(UNW_ARM_R8);
675	_msContext.R9 = r.getRegister(UNW_ARM_R9);
676	_msContext.R10 = r.getRegister(UNW_ARM_R10);
677	_msContext.R11 = r.getRegister(UNW_ARM_R11);
678	_msContext.R12 = r.getRegister(UNW_ARM_R12);
679	_msContext.Sp = r.getRegister(UNW_ARM_SP);
680	_msContext.Lr = r.getRegister(UNW_ARM_LR);
681	_msContext.Pc = r.getRegister(UNW_ARM_IP);
682	for (int i = UNW_ARM_D0; i <= UNW_ARM_D31; ++i) {
683	union {
684	uint64_t w;
685	double d;
686	} d;
687	d.d = r.getFloatRegister(i);
688	_msContext.D[i - UNW_ARM_D0] = d.w;
689	}
690	#elif defined(_LIBUNWIND_TARGET_AARCH64)
691	for (int i = UNW_AARCH64_X0; i <= UNW_ARM64_X30; ++i)
692	_msContext.X[i - UNW_AARCH64_X0] = r.getRegister(i);
693	_msContext.Sp = r.getRegister(UNW_REG_SP);
694	_msContext.Pc = r.getRegister(UNW_REG_IP);
695	for (int i = UNW_AARCH64_V0; i <= UNW_ARM64_D31; ++i)
696	_msContext.V[i - UNW_AARCH64_V0].D[0] = r.getFloatRegister(i);
697	#endif
698	}
699
700	template <typename A, typename R>
701	UnwindCursor<A, R>::UnwindCursor(CONTEXT *context, A &as)
702	: _addressSpace(as), _unwindInfoMissing(false) {
703	static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
704	"UnwindCursor<> does not fit in unw_cursor_t");
705	memset(&_info, 0, sizeof(_info));
706	memset(&_histTable, 0, sizeof(_histTable));
707	memset(&_dispContext, 0, sizeof(_dispContext));
708	_dispContext.ContextRecord = &_msContext;
709	_dispContext.HistoryTable = &_histTable;
710	_msContext = *context;
711	}
712
713
714	template <typename A, typename R>
715	bool UnwindCursor<A, R>::validReg(int regNum) {
716	if (regNum == UNW_REG_IP || regNum == UNW_REG_SP) return true;
717	#if defined(_LIBUNWIND_TARGET_X86_64)
718	if (regNum >= UNW_X86_64_RAX && regNum <= UNW_X86_64_RIP) return true;
719	#elif defined(_LIBUNWIND_TARGET_ARM)
720	if ((regNum >= UNW_ARM_R0 && regNum <= UNW_ARM_R15) ||
721	regNum == UNW_ARM_RA_AUTH_CODE)
722	return true;
723	#elif defined(_LIBUNWIND_TARGET_AARCH64)
724	if (regNum >= UNW_AARCH64_X0 && regNum <= UNW_ARM64_X30) return true;
725	#endif
726	return false;
727	}
728
729	template <typename A, typename R>
730	unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
731	switch (regNum) {
732	#if defined(_LIBUNWIND_TARGET_X86_64)
733	case UNW_X86_64_RIP:
734	case UNW_REG_IP: return _msContext.Rip;
735	case UNW_X86_64_RAX: return _msContext.Rax;
736	case UNW_X86_64_RDX: return _msContext.Rdx;
737	case UNW_X86_64_RCX: return _msContext.Rcx;
738	case UNW_X86_64_RBX: return _msContext.Rbx;
739	case UNW_REG_SP:
740	case UNW_X86_64_RSP: return _msContext.Rsp;
741	case UNW_X86_64_RBP: return _msContext.Rbp;
742	case UNW_X86_64_RSI: return _msContext.Rsi;
743	case UNW_X86_64_RDI: return _msContext.Rdi;
744	case UNW_X86_64_R8: return _msContext.R8;
745	case UNW_X86_64_R9: return _msContext.R9;
746	case UNW_X86_64_R10: return _msContext.R10;
747	case UNW_X86_64_R11: return _msContext.R11;
748	case UNW_X86_64_R12: return _msContext.R12;
749	case UNW_X86_64_R13: return _msContext.R13;
750	case UNW_X86_64_R14: return _msContext.R14;
751	case UNW_X86_64_R15: return _msContext.R15;
752	#elif defined(_LIBUNWIND_TARGET_ARM)
753	case UNW_ARM_R0: return _msContext.R0;
754	case UNW_ARM_R1: return _msContext.R1;
755	case UNW_ARM_R2: return _msContext.R2;
756	case UNW_ARM_R3: return _msContext.R3;
757	case UNW_ARM_R4: return _msContext.R4;
758	case UNW_ARM_R5: return _msContext.R5;
759	case UNW_ARM_R6: return _msContext.R6;
760	case UNW_ARM_R7: return _msContext.R7;
761	case UNW_ARM_R8: return _msContext.R8;
762	case UNW_ARM_R9: return _msContext.R9;
763	case UNW_ARM_R10: return _msContext.R10;
764	case UNW_ARM_R11: return _msContext.R11;
765	case UNW_ARM_R12: return _msContext.R12;
766	case UNW_REG_SP:
767	case UNW_ARM_SP: return _msContext.Sp;
768	case UNW_ARM_LR: return _msContext.Lr;
769	case UNW_REG_IP:
770	case UNW_ARM_IP: return _msContext.Pc;
771	#elif defined(_LIBUNWIND_TARGET_AARCH64)
772	case UNW_REG_SP: return _msContext.Sp;
773	case UNW_REG_IP: return _msContext.Pc;
774	default: return _msContext.X[regNum - UNW_AARCH64_X0];
775	#endif
776	}
777	_LIBUNWIND_ABORT("unsupported register");
778	}
779
780	template <typename A, typename R>
781	void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
782	switch (regNum) {
783	#if defined(_LIBUNWIND_TARGET_X86_64)
784	case UNW_X86_64_RIP:
785	case UNW_REG_IP: _msContext.Rip = value; break;
786	case UNW_X86_64_RAX: _msContext.Rax = value; break;
787	case UNW_X86_64_RDX: _msContext.Rdx = value; break;
788	case UNW_X86_64_RCX: _msContext.Rcx = value; break;
789	case UNW_X86_64_RBX: _msContext.Rbx = value; break;
790	case UNW_REG_SP:
791	case UNW_X86_64_RSP: _msContext.Rsp = value; break;
792	case UNW_X86_64_RBP: _msContext.Rbp = value; break;
793	case UNW_X86_64_RSI: _msContext.Rsi = value; break;
794	case UNW_X86_64_RDI: _msContext.Rdi = value; break;
795	case UNW_X86_64_R8: _msContext.R8 = value; break;
796	case UNW_X86_64_R9: _msContext.R9 = value; break;
797	case UNW_X86_64_R10: _msContext.R10 = value; break;
798	case UNW_X86_64_R11: _msContext.R11 = value; break;
799	case UNW_X86_64_R12: _msContext.R12 = value; break;
800	case UNW_X86_64_R13: _msContext.R13 = value; break;
801	case UNW_X86_64_R14: _msContext.R14 = value; break;
802	case UNW_X86_64_R15: _msContext.R15 = value; break;
803	#elif defined(_LIBUNWIND_TARGET_ARM)
804	case UNW_ARM_R0: _msContext.R0 = value; break;
805	case UNW_ARM_R1: _msContext.R1 = value; break;
806	case UNW_ARM_R2: _msContext.R2 = value; break;
807	case UNW_ARM_R3: _msContext.R3 = value; break;
808	case UNW_ARM_R4: _msContext.R4 = value; break;
809	case UNW_ARM_R5: _msContext.R5 = value; break;
810	case UNW_ARM_R6: _msContext.R6 = value; break;
811	case UNW_ARM_R7: _msContext.R7 = value; break;
812	case UNW_ARM_R8: _msContext.R8 = value; break;
813	case UNW_ARM_R9: _msContext.R9 = value; break;
814	case UNW_ARM_R10: _msContext.R10 = value; break;
815	case UNW_ARM_R11: _msContext.R11 = value; break;
816	case UNW_ARM_R12: _msContext.R12 = value; break;
817	case UNW_REG_SP:
818	case UNW_ARM_SP: _msContext.Sp = value; break;
819	case UNW_ARM_LR: _msContext.Lr = value; break;
820	case UNW_REG_IP:
821	case UNW_ARM_IP: _msContext.Pc = value; break;
822	#elif defined(_LIBUNWIND_TARGET_AARCH64)
823	case UNW_REG_SP: _msContext.Sp = value; break;
824	case UNW_REG_IP: _msContext.Pc = value; break;
825	case UNW_AARCH64_X0:
826	case UNW_AARCH64_X1:
827	case UNW_AARCH64_X2:
828	case UNW_AARCH64_X3:
829	case UNW_AARCH64_X4:
830	case UNW_AARCH64_X5:
831	case UNW_AARCH64_X6:
832	case UNW_AARCH64_X7:
833	case UNW_AARCH64_X8:
834	case UNW_AARCH64_X9:
835	case UNW_AARCH64_X10:
836	case UNW_AARCH64_X11:
837	case UNW_AARCH64_X12:
838	case UNW_AARCH64_X13:
839	case UNW_AARCH64_X14:
840	case UNW_AARCH64_X15:
841	case UNW_AARCH64_X16:
842	case UNW_AARCH64_X17:
843	case UNW_AARCH64_X18:
844	case UNW_AARCH64_X19:
845	case UNW_AARCH64_X20:
846	case UNW_AARCH64_X21:
847	case UNW_AARCH64_X22:
848	case UNW_AARCH64_X23:
849	case UNW_AARCH64_X24:
850	case UNW_AARCH64_X25:
851	case UNW_AARCH64_X26:
852	case UNW_AARCH64_X27:
853	case UNW_AARCH64_X28:
854	case UNW_AARCH64_FP:
855	case UNW_AARCH64_LR: _msContext.X[regNum - UNW_ARM64_X0] = value; break;
856	#endif
857	default:
858	_LIBUNWIND_ABORT("unsupported register");
859	}
860	}
861
862	template <typename A, typename R>
863	bool UnwindCursor<A, R>::validFloatReg(int regNum) {
864	#if defined(_LIBUNWIND_TARGET_ARM)
865	if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) return true;
866	if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) return true;
867	#elif defined(_LIBUNWIND_TARGET_AARCH64)
868	if (regNum >= UNW_AARCH64_V0 && regNum <= UNW_ARM64_D31) return true;
869	#else
870	(void)regNum;
871	#endif
872	return false;
873	}
874
875	template <typename A, typename R>
876	unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
877	#if defined(_LIBUNWIND_TARGET_ARM)
878	if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) {
879	union {
880	uint32_t w;
881	float f;
882	} d;
883	d.w = _msContext.S[regNum - UNW_ARM_S0];
884	return d.f;
885	}
886	if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {
887	union {
888	uint64_t w;
889	double d;
890	} d;
891	d.w = _msContext.D[regNum - UNW_ARM_D0];
892	return d.d;
893	}
894	_LIBUNWIND_ABORT("unsupported float register");
895	#elif defined(_LIBUNWIND_TARGET_AARCH64)
896	return _msContext.V[regNum - UNW_AARCH64_V0].D[0];
897	#else
898	(void)regNum;
899	_LIBUNWIND_ABORT("float registers unimplemented");
900	#endif
901	}
902
903	template <typename A, typename R>
904	void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
905	#if defined(_LIBUNWIND_TARGET_ARM)
906	if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) {
907	union {
908	uint32_t w;
909	float f;
910	} d;
911	d.f = (float)value;
912	_msContext.S[regNum - UNW_ARM_S0] = d.w;
913	}
914	if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {
915	union {
916	uint64_t w;
917	double d;
918	} d;
919	d.d = value;
920	_msContext.D[regNum - UNW_ARM_D0] = d.w;
921	}
922	_LIBUNWIND_ABORT("unsupported float register");
923	#elif defined(_LIBUNWIND_TARGET_AARCH64)
924	_msContext.V[regNum - UNW_AARCH64_V0].D[0] = value;
925	#else
926	(void)regNum;
927	(void)value;
928	_LIBUNWIND_ABORT("float registers unimplemented");
929	#endif
930	}
931
932	template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
933	RtlRestoreContext(&_msContext, nullptr);
934	}
935
936	#ifdef __arm__
937	template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {}
938	#endif
939
940	template <typename A, typename R>
941	const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
942	return R::getRegisterName(regNum);
943	}
944
945	template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
946	return false;
947	}
948
949	#else // !defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) || !defined(_WIN32)
950
951	/// UnwindCursor contains all state (including all register values) during
952	/// an unwind. This is normally stack allocated inside a unw_cursor_t.
953	template <typename A, typename R>
954	class UnwindCursor : public AbstractUnwindCursor{
955	typedef typename A::pint_t pint_t;
956	public:
957	UnwindCursor(unw_context_t *context, A &as);
958	UnwindCursor(A &as, void *threadArg);
959	virtual ~UnwindCursor() {}
960	virtual bool validReg(int);
961	virtual unw_word_t getReg(int);
962	virtual void setReg(int, unw_word_t);
963	virtual bool validFloatReg(int);
964	virtual unw_fpreg_t getFloatReg(int);
965	virtual void setFloatReg(int, unw_fpreg_t);
966	virtual int step(bool stage2 = false);
967	virtual void getInfo(unw_proc_info_t *);
968	virtual void jumpto();
969	virtual bool isSignalFrame();
970	virtual bool getFunctionName(char *buf, size_t len, unw_word_t *off);
971	virtual void setInfoBasedOnIPRegister(bool isReturnAddress = false);
972	virtual const char *getRegisterName(int num);
973	#ifdef __arm__
974	virtual void saveVFPAsX();
975	#endif
976
977	#ifdef _AIX
978	virtual uintptr_t getDataRelBase();
979	#endif
980
981	#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
982	virtual void *get_registers() { return &_registers; }
983	#endif
984
985	// libunwind does not and should not depend on C++ library which means that we
986	// need our own definition of inline placement new.
987	static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
988
989	private:
990
991	#if defined(_LIBUNWIND_ARM_EHABI)
992	bool getInfoFromEHABISection(pint_t pc, const UnwindInfoSections &sects);
993
994	int stepWithEHABI() {
995	size_t len = 0;
996	size_t off = 0;
997	// FIXME: Calling decode_eht_entry() here is violating the libunwind
998	// abstraction layer.
999	const uint32_t *ehtp =
1000	decode_eht_entry(reinterpret_cast<const uint32_t *>(_info.unwind_info),
1001	&off, &len);
1002	if (_Unwind_VRS_Interpret((_Unwind_Context *)this, ehtp, off, len) !=
1003	_URC_CONTINUE_UNWIND)
1004	return UNW_STEP_END;
1005	return UNW_STEP_SUCCESS;
1006	}
1007	#endif
1008
1009	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
1010	bool setInfoForSigReturn() {
1011	R dummy;
1012	return setInfoForSigReturn(dummy);
1013	}
1014	int stepThroughSigReturn() {
1015	R dummy;
1016	return stepThroughSigReturn(dummy);
1017	}
1018	bool isReadableAddr(const pint_t addr) const;
1019	#if defined(_LIBUNWIND_TARGET_AARCH64)
1020	bool setInfoForSigReturn(Registers_arm64 &);
1021	int stepThroughSigReturn(Registers_arm64 &);
1022	#endif
1023	#if defined(_LIBUNWIND_TARGET_LOONGARCH)
1024	bool setInfoForSigReturn(Registers_loongarch &);
1025	int stepThroughSigReturn(Registers_loongarch &);
1026	#endif
1027	#if defined(_LIBUNWIND_TARGET_RISCV)
1028	bool setInfoForSigReturn(Registers_riscv &);
1029	int stepThroughSigReturn(Registers_riscv &);
1030	#endif
1031	#if defined(_LIBUNWIND_TARGET_S390X)
1032	bool setInfoForSigReturn(Registers_s390x &);
1033	int stepThroughSigReturn(Registers_s390x &);
1034	#endif
1035	template <typename Registers> bool setInfoForSigReturn(Registers &) {
1036	return false;
1037	}
1038	template <typename Registers> int stepThroughSigReturn(Registers &) {
1039	return UNW_STEP_END;
1040	}
1041	#elif defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
1042	bool setInfoForSigReturn();
1043	int stepThroughSigReturn();
1044	#endif
1045
1046	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1047	bool getInfoFromFdeCie(const typename CFI_Parser<A>::FDE_Info &fdeInfo,
1048	const typename CFI_Parser<A>::CIE_Info &cieInfo,
1049	pint_t pc, uintptr_t dso_base);
1050	bool getInfoFromDwarfSection(pint_t pc, const UnwindInfoSections &sects,
1051	uint32_t fdeSectionOffsetHint=0);
1052	int stepWithDwarfFDE(bool stage2) {
1053	return DwarfInstructions<A, R>::stepWithDwarf(
1054	_addressSpace, (pint_t)this->getReg(UNW_REG_IP),
1055	(pint_t)_info.unwind_info, _registers, _isSignalFrame, stage2);
1056	}
1057	#endif
1058
1059	#if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1060	bool getInfoFromCompactEncodingSection(pint_t pc,
1061	const UnwindInfoSections &sects);
1062	int stepWithCompactEncoding(bool stage2 = false) {
1063	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1064	if ( compactSaysUseDwarf() )
1065	return stepWithDwarfFDE(stage2);
1066	#endif
1067	R dummy;
1068	return stepWithCompactEncoding(dummy);
1069	}
1070
1071	#if defined(_LIBUNWIND_TARGET_X86_64)
1072	int stepWithCompactEncoding(Registers_x86_64 &) {
1073	return CompactUnwinder_x86_64<A>::stepWithCompactEncoding(
1074	_info.format, _info.start_ip, _addressSpace, _registers);
1075	}
1076	#endif
1077
1078	#if defined(_LIBUNWIND_TARGET_I386)
1079	int stepWithCompactEncoding(Registers_x86 &) {
1080	return CompactUnwinder_x86<A>::stepWithCompactEncoding(
1081	_info.format, (uint32_t)_info.start_ip, _addressSpace, _registers);
1082	}
1083	#endif
1084
1085	#if defined(_LIBUNWIND_TARGET_PPC)
1086	int stepWithCompactEncoding(Registers_ppc &) {
1087	return UNW_EINVAL;
1088	}
1089	#endif
1090
1091	#if defined(_LIBUNWIND_TARGET_PPC64)
1092	int stepWithCompactEncoding(Registers_ppc64 &) {
1093	return UNW_EINVAL;
1094	}
1095	#endif
1096
1097
1098	#if defined(_LIBUNWIND_TARGET_AARCH64)
1099	int stepWithCompactEncoding(Registers_arm64 &) {
1100	return CompactUnwinder_arm64<A>::stepWithCompactEncoding(
1101	_info.format, _info.start_ip, _addressSpace, _registers);
1102	}
1103	#endif
1104
1105	#if defined(_LIBUNWIND_TARGET_MIPS_O32)
1106	int stepWithCompactEncoding(Registers_mips_o32 &) {
1107	return UNW_EINVAL;
1108	}
1109	#endif
1110
1111	#if defined(_LIBUNWIND_TARGET_MIPS_NEWABI)
1112	int stepWithCompactEncoding(Registers_mips_newabi &) {
1113	return UNW_EINVAL;
1114	}
1115	#endif
1116
1117	#if defined(_LIBUNWIND_TARGET_LOONGARCH)
1118	int stepWithCompactEncoding(Registers_loongarch &) { return UNW_EINVAL; }
1119	#endif
1120
1121	#if defined(_LIBUNWIND_TARGET_SPARC)
1122	int stepWithCompactEncoding(Registers_sparc &) { return UNW_EINVAL; }
1123	#endif
1124
1125	#if defined(_LIBUNWIND_TARGET_SPARC64)
1126	int stepWithCompactEncoding(Registers_sparc64 &) { return UNW_EINVAL; }
1127	#endif
1128
1129	#if defined (_LIBUNWIND_TARGET_RISCV)
1130	int stepWithCompactEncoding(Registers_riscv &) {
1131	return UNW_EINVAL;
1132	}
1133	#endif
1134
1135	bool compactSaysUseDwarf(uint32_t *offset=NULL) const {
1136	R dummy;
1137	return compactSaysUseDwarf(dummy, offset);
1138	}
1139
1140	#if defined(_LIBUNWIND_TARGET_X86_64)
1141	bool compactSaysUseDwarf(Registers_x86_64 &, uint32_t *offset) const {
1142	if ((_info.format & UNWIND_X86_64_MODE_MASK) == UNWIND_X86_64_MODE_DWARF) {
1143	if (offset)
1144	*offset = (_info.format & UNWIND_X86_64_DWARF_SECTION_OFFSET);
1145	return true;
1146	}
1147	return false;
1148	}
1149	#endif
1150
1151	#if defined(_LIBUNWIND_TARGET_I386)
1152	bool compactSaysUseDwarf(Registers_x86 &, uint32_t *offset) const {
1153	if ((_info.format & UNWIND_X86_MODE_MASK) == UNWIND_X86_MODE_DWARF) {
1154	if (offset)
1155	*offset = (_info.format & UNWIND_X86_DWARF_SECTION_OFFSET);
1156	return true;
1157	}
1158	return false;
1159	}
1160	#endif
1161
1162	#if defined(_LIBUNWIND_TARGET_PPC)
1163	bool compactSaysUseDwarf(Registers_ppc &, uint32_t *) const {
1164	return true;
1165	}
1166	#endif
1167
1168	#if defined(_LIBUNWIND_TARGET_PPC64)
1169	bool compactSaysUseDwarf(Registers_ppc64 &, uint32_t *) const {
1170	return true;
1171	}
1172	#endif
1173
1174	#if defined(_LIBUNWIND_TARGET_AARCH64)
1175	bool compactSaysUseDwarf(Registers_arm64 &, uint32_t *offset) const {
1176	if ((_info.format & UNWIND_ARM64_MODE_MASK) == UNWIND_ARM64_MODE_DWARF) {
1177	if (offset)
1178	*offset = (_info.format & UNWIND_ARM64_DWARF_SECTION_OFFSET);
1179	return true;
1180	}
1181	return false;
1182	}
1183	#endif
1184
1185	#if defined(_LIBUNWIND_TARGET_MIPS_O32)
1186	bool compactSaysUseDwarf(Registers_mips_o32 &, uint32_t *) const {
1187	return true;
1188	}
1189	#endif
1190
1191	#if defined(_LIBUNWIND_TARGET_MIPS_NEWABI)
1192	bool compactSaysUseDwarf(Registers_mips_newabi &, uint32_t *) const {
1193	return true;
1194	}
1195	#endif
1196
1197	#if defined(_LIBUNWIND_TARGET_LOONGARCH)
1198	bool compactSaysUseDwarf(Registers_loongarch &, uint32_t *) const {
1199	return true;
1200	}
1201	#endif
1202
1203	#if defined(_LIBUNWIND_TARGET_SPARC)
1204	bool compactSaysUseDwarf(Registers_sparc &, uint32_t *) const { return true; }
1205	#endif
1206
1207	#if defined(_LIBUNWIND_TARGET_SPARC64)
1208	bool compactSaysUseDwarf(Registers_sparc64 &, uint32_t *) const {
1209	return true;
1210	}
1211	#endif
1212
1213	#if defined (_LIBUNWIND_TARGET_RISCV)
1214	bool compactSaysUseDwarf(Registers_riscv &, uint32_t *) const {
1215	return true;
1216	}
1217	#endif
1218
1219	#endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1220
1221	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1222	compact_unwind_encoding_t dwarfEncoding() const {
1223	R dummy;
1224	return dwarfEncoding(dummy);
1225	}
1226
1227	#if defined(_LIBUNWIND_TARGET_X86_64)
1228	compact_unwind_encoding_t dwarfEncoding(Registers_x86_64 &) const {
1229	return UNWIND_X86_64_MODE_DWARF;
1230	}
1231	#endif
1232
1233	#if defined(_LIBUNWIND_TARGET_I386)
1234	compact_unwind_encoding_t dwarfEncoding(Registers_x86 &) const {
1235	return UNWIND_X86_MODE_DWARF;
1236	}
1237	#endif
1238
1239	#if defined(_LIBUNWIND_TARGET_PPC)
1240	compact_unwind_encoding_t dwarfEncoding(Registers_ppc &) const {
1241	return 0;
1242	}
1243	#endif
1244
1245	#if defined(_LIBUNWIND_TARGET_PPC64)
1246	compact_unwind_encoding_t dwarfEncoding(Registers_ppc64 &) const {
1247	return 0;
1248	}
1249	#endif
1250
1251	#if defined(_LIBUNWIND_TARGET_AARCH64)
1252	compact_unwind_encoding_t dwarfEncoding(Registers_arm64 &) const {
1253	return UNWIND_ARM64_MODE_DWARF;
1254	}
1255	#endif
1256
1257	#if defined(_LIBUNWIND_TARGET_ARM)
1258	compact_unwind_encoding_t dwarfEncoding(Registers_arm &) const {
1259	return 0;
1260	}
1261	#endif
1262
1263	#if defined (_LIBUNWIND_TARGET_OR1K)
1264	compact_unwind_encoding_t dwarfEncoding(Registers_or1k &) const {
1265	return 0;
1266	}
1267	#endif
1268
1269	#if defined (_LIBUNWIND_TARGET_HEXAGON)
1270	compact_unwind_encoding_t dwarfEncoding(Registers_hexagon &) const {
1271	return 0;
1272	}
1273	#endif
1274
1275	#if defined (_LIBUNWIND_TARGET_MIPS_O32)
1276	compact_unwind_encoding_t dwarfEncoding(Registers_mips_o32 &) const {
1277	return 0;
1278	}
1279	#endif
1280
1281	#if defined (_LIBUNWIND_TARGET_MIPS_NEWABI)
1282	compact_unwind_encoding_t dwarfEncoding(Registers_mips_newabi &) const {
1283	return 0;
1284	}
1285	#endif
1286
1287	#if defined(_LIBUNWIND_TARGET_LOONGARCH)
1288	compact_unwind_encoding_t dwarfEncoding(Registers_loongarch &) const {
1289	return 0;
1290	}
1291	#endif
1292
1293	#if defined(_LIBUNWIND_TARGET_SPARC)
1294	compact_unwind_encoding_t dwarfEncoding(Registers_sparc &) const { return 0; }
1295	#endif
1296
1297	#if defined(_LIBUNWIND_TARGET_SPARC64)
1298	compact_unwind_encoding_t dwarfEncoding(Registers_sparc64 &) const {
1299	return 0;
1300	}
1301	#endif
1302
1303	#if defined (_LIBUNWIND_TARGET_RISCV)
1304	compact_unwind_encoding_t dwarfEncoding(Registers_riscv &) const {
1305	return 0;
1306	}
1307	#endif
1308
1309	#if defined (_LIBUNWIND_TARGET_S390X)
1310	compact_unwind_encoding_t dwarfEncoding(Registers_s390x &) const {
1311	return 0;
1312	}
1313	#endif
1314
1315	#endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1316
1317	#if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1318	// For runtime environments using SEH unwind data without Windows runtime
1319	// support.
1320	pint_t getLastPC() const { /* FIXME: Implement */ return 0; }
1321	void setLastPC(pint_t pc) { /* FIXME: Implement */ }
1322	RUNTIME_FUNCTION *lookUpSEHUnwindInfo(pint_t pc, pint_t *base) {
1323	/* FIXME: Implement */
1324	*base = 0;
1325	return nullptr;
1326	}
1327	bool getInfoFromSEH(pint_t pc);
1328	int stepWithSEHData() { /* FIXME: Implement */ return 0; }
1329	#endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1330
1331	#if defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
1332	bool getInfoFromTBTable(pint_t pc, R &registers);
1333	int stepWithTBTable(pint_t pc, tbtable *TBTable, R &registers,
1334	bool &isSignalFrame);
1335	int stepWithTBTableData() {
1336	return stepWithTBTable(reinterpret_cast<pint_t>(this->getReg(UNW_REG_IP)),
1337	reinterpret_cast<tbtable *>(_info.unwind_info),
1338	_registers, _isSignalFrame);
1339	}
1340	#endif // defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
1341
1342	A &_addressSpace;
1343	R _registers;
1344	unw_proc_info_t _info;
1345	bool _unwindInfoMissing;
1346	bool _isSignalFrame;
1347	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) || \
1348	defined(_LIBUNWIND_TARGET_HAIKU)
1349	bool _isSigReturn = false;
1350	#endif
1351	};
1352
1353
1354	template <typename A, typename R>
1355	UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
1356	: _addressSpace(as), _registers(context), _unwindInfoMissing(false),
1357	_isSignalFrame(false) {
1358	static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
1359	"UnwindCursor<> does not fit in unw_cursor_t");
1360	static_assert((alignof(UnwindCursor<A, R>) <= alignof(unw_cursor_t)),
1361	"UnwindCursor<> requires more alignment than unw_cursor_t");
1362	memset(s: &_info, c: 0, n: sizeof(_info));
1363	}
1364
1365	template <typename A, typename R>
1366	UnwindCursor<A, R>::UnwindCursor(A &as, void *)
1367	: _addressSpace(as), _unwindInfoMissing(false), _isSignalFrame(false) {
1368	memset(s: &_info, c: 0, n: sizeof(_info));
1369	// FIXME
1370	// fill in _registers from thread arg
1371	}
1372
1373
1374	template <typename A, typename R>
1375	bool UnwindCursor<A, R>::validReg(int regNum) {
1376	return _registers.validRegister(regNum);
1377	}
1378
1379	template <typename A, typename R>
1380	unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
1381	return _registers.getRegister(regNum);
1382	}
1383
1384	template <typename A, typename R>
1385	void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
1386	_registers.setRegister(regNum, (typename A::pint_t)value);
1387	}
1388
1389	template <typename A, typename R>
1390	bool UnwindCursor<A, R>::validFloatReg(int regNum) {
1391	return _registers.validFloatRegister(regNum);
1392	}
1393
1394	template <typename A, typename R>
1395	unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
1396	return _registers.getFloatRegister(regNum);
1397	}
1398
1399	template <typename A, typename R>
1400	void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
1401	_registers.setFloatRegister(regNum, value);
1402	}
1403
1404	template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
1405	_registers.jumpto();
1406	}
1407
1408	#ifdef __arm__
1409	template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {
1410	_registers.saveVFPAsX();
1411	}
1412	#endif
1413
1414	#ifdef _AIX
1415	template <typename A, typename R>
1416	uintptr_t UnwindCursor<A, R>::getDataRelBase() {
1417	return reinterpret_cast<uintptr_t>(_info.extra);
1418	}
1419	#endif
1420
1421	template <typename A, typename R>
1422	const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
1423	return _registers.getRegisterName(regNum);
1424	}
1425
1426	template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
1427	return _isSignalFrame;
1428	}
1429
1430	#endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1431
1432	#if defined(_LIBUNWIND_ARM_EHABI)
1433	template<typename A>
1434	struct EHABISectionIterator {
1435	typedef EHABISectionIterator _Self;
1436
1437	typedef typename A::pint_t value_type;
1438	typedef typename A::pint_t* pointer;
1439	typedef typename A::pint_t& reference;
1440	typedef size_t size_type;
1441	typedef size_t difference_type;
1442
1443	static _Self begin(A& addressSpace, const UnwindInfoSections& sects) {
1444	return _Self(addressSpace, sects, 0);
1445	}
1446	static _Self end(A& addressSpace, const UnwindInfoSections& sects) {
1447	return _Self(addressSpace, sects,
1448	sects.arm_section_length / sizeof(EHABIIndexEntry));
1449	}
1450
1451	EHABISectionIterator(A& addressSpace, const UnwindInfoSections& sects, size_t i)
1452	: _i(i), _addressSpace(&addressSpace), _sects(&sects) {}
1453
1454	_Self& operator++() { ++_i; return *this; }
1455	_Self& operator+=(size_t a) { _i += a; return *this; }
1456	_Self& operator--() { assert(_i > 0); --_i; return *this; }
1457	_Self& operator-=(size_t a) { assert(_i >= a); _i -= a; return *this; }
1458
1459	_Self operator+(size_t a) { _Self out = *this; out._i += a; return out; }
1460	_Self operator-(size_t a) { assert(_i >= a); _Self out = *this; out._i -= a; return out; }
1461
1462	size_t operator-(const _Self& other) const { return _i - other._i; }
1463
1464	bool operator==(const _Self& other) const {
1465	assert(_addressSpace == other._addressSpace);
1466	assert(_sects == other._sects);
1467	return _i == other._i;
1468	}
1469
1470	bool operator!=(const _Self& other) const {
1471	assert(_addressSpace == other._addressSpace);
1472	assert(_sects == other._sects);
1473	return _i != other._i;
1474	}
1475
1476	typename A::pint_t operator*() const { return functionAddress(); }
1477
1478	typename A::pint_t functionAddress() const {
1479	typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
1480	EHABIIndexEntry, _i, functionOffset);
1481	return indexAddr + signExtendPrel31(_addressSpace->get32(indexAddr));
1482	}
1483
1484	typename A::pint_t dataAddress() {
1485	typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
1486	EHABIIndexEntry, _i, data);
1487	return indexAddr;
1488	}
1489
1490	private:
1491	size_t _i;
1492	A* _addressSpace;
1493	const UnwindInfoSections* _sects;
1494	};
1495
1496	namespace {
1497
1498	template <typename A>
1499	EHABISectionIterator<A> EHABISectionUpperBound(
1500	EHABISectionIterator<A> first,
1501	EHABISectionIterator<A> last,
1502	typename A::pint_t value) {
1503	size_t len = last - first;
1504	while (len > 0) {
1505	size_t l2 = len / 2;
1506	EHABISectionIterator<A> m = first + l2;
1507	if (value < *m) {
1508	len = l2;
1509	} else {
1510	first = ++m;
1511	len -= l2 + 1;
1512	}
1513	}
1514	return first;
1515	}
1516
1517	}
1518
1519	template <typename A, typename R>
1520	bool UnwindCursor<A, R>::getInfoFromEHABISection(
1521	pint_t pc,
1522	const UnwindInfoSections &sects) {
1523	EHABISectionIterator<A> begin =
1524	EHABISectionIterator<A>::begin(_addressSpace, sects);
1525	EHABISectionIterator<A> end =
1526	EHABISectionIterator<A>::end(_addressSpace, sects);
1527	if (begin == end)
1528	return false;
1529
1530	EHABISectionIterator<A> itNextPC = EHABISectionUpperBound(begin, end, pc);
1531	if (itNextPC == begin)
1532	return false;
1533	EHABISectionIterator<A> itThisPC = itNextPC - 1;
1534
1535	pint_t thisPC = itThisPC.functionAddress();
1536	// If an exception is thrown from a function, corresponding to the last entry
1537	// in the table, we don't really know the function extent and have to choose a
1538	// value for nextPC. Choosing max() will allow the range check during trace to
1539	// succeed.
1540	pint_t nextPC = (itNextPC == end) ? UINTPTR_MAX : itNextPC.functionAddress();
1541	pint_t indexDataAddr = itThisPC.dataAddress();
1542
1543	if (indexDataAddr == 0)
1544	return false;
1545
1546	uint32_t indexData = _addressSpace.get32(indexDataAddr);
1547	if (indexData == UNW_EXIDX_CANTUNWIND)
1548	return false;
1549
1550	// If the high bit is set, the exception handling table entry is inline inside
1551	// the index table entry on the second word (aka |indexDataAddr|). Otherwise,
1552	// the table points at an offset in the exception handling table (section 5
1553	// EHABI).
1554	pint_t exceptionTableAddr;
1555	uint32_t exceptionTableData;
1556	bool isSingleWordEHT;
1557	if (indexData & 0x80000000) {
1558	exceptionTableAddr = indexDataAddr;
1559	// TODO(ajwong): Should this data be 0?
1560	exceptionTableData = indexData;
1561	isSingleWordEHT = true;
1562	} else {
1563	exceptionTableAddr = indexDataAddr + signExtendPrel31(indexData);
1564	exceptionTableData = _addressSpace.get32(exceptionTableAddr);
1565	isSingleWordEHT = false;
1566	}
1567
1568	// Now we know the 3 things:
1569	// exceptionTableAddr -- exception handler table entry.
1570	// exceptionTableData -- the data inside the first word of the eht entry.
1571	// isSingleWordEHT -- whether the entry is in the index.
1572	unw_word_t personalityRoutine = 0xbadf00d;
1573	bool scope32 = false;
1574	uintptr_t lsda;
1575
1576	// If the high bit in the exception handling table entry is set, the entry is
1577	// in compact form (section 6.3 EHABI).
1578	if (exceptionTableData & 0x80000000) {
1579	// Grab the index of the personality routine from the compact form.
1580	uint32_t choice = (exceptionTableData & 0x0f000000) >> 24;
1581	uint32_t extraWords = 0;
1582	switch (choice) {
1583	case 0:
1584	personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr0;
1585	extraWords = 0;
1586	scope32 = false;
1587	lsda = isSingleWordEHT ? 0 : (exceptionTableAddr + 4);
1588	break;
1589	case 1:
1590	personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr1;
1591	extraWords = (exceptionTableData & 0x00ff0000) >> 16;
1592	scope32 = false;
1593	lsda = exceptionTableAddr + (extraWords + 1) * 4;
1594	break;
1595	case 2:
1596	personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr2;
1597	extraWords = (exceptionTableData & 0x00ff0000) >> 16;
1598	scope32 = true;
1599	lsda = exceptionTableAddr + (extraWords + 1) * 4;
1600	break;
1601	default:
1602	_LIBUNWIND_ABORT("unknown personality routine");
1603	return false;
1604	}
1605
1606	if (isSingleWordEHT) {
1607	if (extraWords != 0) {
1608	_LIBUNWIND_ABORT("index inlined table detected but pr function "
1609	"requires extra words");
1610	return false;
1611	}
1612	}
1613	} else {
1614	pint_t personalityAddr =
1615	exceptionTableAddr + signExtendPrel31(exceptionTableData);
1616	personalityRoutine = personalityAddr;
1617
1618	// ARM EHABI # 6.2, # 9.2
1619	//
1620	// +---- ehtp
1621	// v
1622	// +--------------------------------------+
1623	// | +--------+--------+--------+-------+ |
1624	// | |0| prel31 to personalityRoutine | |
1625	// | +--------+--------+--------+-------+ |
1626	// | | N | unwind opcodes | | <-- UnwindData
1627	// | +--------+--------+--------+-------+ |
1628	// | | Word 2 unwind opcodes | |
1629	// | +--------+--------+--------+-------+ |
1630	// | ... |
1631	// | +--------+--------+--------+-------+ |
1632	// | | Word N unwind opcodes | |
1633	// | +--------+--------+--------+-------+ |
1634	// | | LSDA | | <-- lsda
1635	// | | ... | |
1636	// | +--------+--------+--------+-------+ |
1637	// +--------------------------------------+
1638
1639	uint32_t *UnwindData = reinterpret_cast<uint32_t*>(exceptionTableAddr) + 1;
1640	uint32_t FirstDataWord = *UnwindData;
1641	size_t N = ((FirstDataWord >> 24) & 0xff);
1642	size_t NDataWords = N + 1;
1643	lsda = reinterpret_cast<uintptr_t>(UnwindData + NDataWords);
1644	}
1645
1646	_info.start_ip = thisPC;
1647	_info.end_ip = nextPC;
1648	_info.handler = personalityRoutine;
1649	_info.unwind_info = exceptionTableAddr;
1650	_info.lsda = lsda;
1651	// flags is pr_cache.additional. See EHABI #7.2 for definition of bit 0.
1652	_info.flags = (isSingleWordEHT ? 1 : 0) | (scope32 ? 0x2 : 0); // Use enum?
1653
1654	return true;
1655	}
1656	#endif
1657
1658	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1659	template <typename A, typename R>
1660	bool UnwindCursor<A, R>::getInfoFromFdeCie(
1661	const typename CFI_Parser<A>::FDE_Info &fdeInfo,
1662	const typename CFI_Parser<A>::CIE_Info &cieInfo, pint_t pc,
1663	uintptr_t dso_base) {
1664	typename CFI_Parser<A>::PrologInfo prolog;
1665	if (CFI_Parser<A>::parseFDEInstructions(_addressSpace, fdeInfo, cieInfo, pc,
1666	R::getArch(), &prolog)) {
1667	// Save off parsed FDE info
1668	_info.start_ip = fdeInfo.pcStart;
1669	_info.end_ip = fdeInfo.pcEnd;
1670	_info.lsda = fdeInfo.lsda;
1671	_info.handler = cieInfo.personality;
1672	// Some frameless functions need SP altered when resuming in function, so
1673	// propagate spExtraArgSize.
1674	_info.gp = prolog.spExtraArgSize;
1675	_info.flags = 0;
1676	_info.format = dwarfEncoding();
1677	_info.unwind_info = fdeInfo.fdeStart;
1678	_info.unwind_info_size = static_cast<uint32_t>(fdeInfo.fdeLength);
1679	_info.extra = static_cast<unw_word_t>(dso_base);
1680	return true;
1681	}
1682	return false;
1683	}
1684
1685	template <typename A, typename R>
1686	bool UnwindCursor<A, R>::getInfoFromDwarfSection(pint_t pc,
1687	const UnwindInfoSections &sects,
1688	uint32_t fdeSectionOffsetHint) {
1689	typename CFI_Parser<A>::FDE_Info fdeInfo;
1690	typename CFI_Parser<A>::CIE_Info cieInfo;
1691	bool foundFDE = false;
1692	bool foundInCache = false;
1693	// If compact encoding table gave offset into dwarf section, go directly there
1694	if (fdeSectionOffsetHint != 0) {
1695	foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1696	sects.dwarf_section_length,
1697	sects.dwarf_section + fdeSectionOffsetHint,
1698	&fdeInfo, &cieInfo);
1699	}
1700	#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
1701	if (!foundFDE && (sects.dwarf_index_section != 0)) {
1702	foundFDE = EHHeaderParser<A>::findFDE(
1703	_addressSpace, pc, sects.dwarf_index_section,
1704	(uint32_t)sects.dwarf_index_section_length, &fdeInfo, &cieInfo);
1705	}
1706	#endif
1707	if (!foundFDE) {
1708	// otherwise, search cache of previously found FDEs.
1709	pint_t cachedFDE = DwarfFDECache<A>::findFDE(sects.dso_base, pc);
1710	if (cachedFDE != 0) {
1711	foundFDE =
1712	CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1713	sects.dwarf_section_length,
1714	cachedFDE, &fdeInfo, &cieInfo);
1715	foundInCache = foundFDE;
1716	}
1717	}
1718	if (!foundFDE) {
1719	// Still not found, do full scan of __eh_frame section.
1720	foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1721	sects.dwarf_section_length, 0,
1722	&fdeInfo, &cieInfo);
1723	}
1724	if (foundFDE) {
1725	if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, dso_base: sects.dso_base)) {
1726	// Add to cache (to make next lookup faster) if we had no hint
1727	// and there was no index.
1728	if (!foundInCache && (fdeSectionOffsetHint == 0)) {
1729	#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
1730	if (sects.dwarf_index_section == 0)
1731	#endif
1732	DwarfFDECache<A>::add(sects.dso_base, fdeInfo.pcStart, fdeInfo.pcEnd,
1733	fdeInfo.fdeStart);
1734	}
1735	return true;
1736	}
1737	}
1738	//_LIBUNWIND_DEBUG_LOG("can't find/use FDE for pc=0x%llX", (uint64_t)pc);
1739	return false;
1740	}
1741	#endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1742
1743
1744	#if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1745	template <typename A, typename R>
1746	bool UnwindCursor<A, R>::getInfoFromCompactEncodingSection(pint_t pc,
1747	const UnwindInfoSections &sects) {
1748	const bool log = false;
1749	if (log)
1750	fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX, mh=0x%llX)\n",
1751	(uint64_t)pc, (uint64_t)sects.dso_base);
1752
1753	const UnwindSectionHeader<A> sectionHeader(_addressSpace,
1754	sects.compact_unwind_section);
1755	if (sectionHeader.version() != UNWIND_SECTION_VERSION)
1756	return false;
1757
1758	// do a binary search of top level index to find page with unwind info
1759	pint_t targetFunctionOffset = pc - sects.dso_base;
1760	const UnwindSectionIndexArray<A> topIndex(_addressSpace,
1761	sects.compact_unwind_section
1762	+ sectionHeader.indexSectionOffset());
1763	uint32_t low = 0;
1764	uint32_t high = sectionHeader.indexCount();
1765	uint32_t last = high - 1;
1766	while (low < high) {
1767	uint32_t mid = (low + high) / 2;
1768	//if ( log ) fprintf(stderr, "\tmid=%d, low=%d, high=%d, *mid=0x%08X\n",
1769	//mid, low, high, topIndex.functionOffset(mid));
1770	if (topIndex.functionOffset(mid) <= targetFunctionOffset) {
1771	if ((mid == last) ||
1772	(topIndex.functionOffset(mid + 1) > targetFunctionOffset)) {
1773	low = mid;
1774	break;
1775	} else {
1776	low = mid + 1;
1777	}
1778	} else {
1779	high = mid;
1780	}
1781	}
1782	const uint32_t firstLevelFunctionOffset = topIndex.functionOffset(low);
1783	const uint32_t firstLevelNextPageFunctionOffset =
1784	topIndex.functionOffset(low + 1);
1785	const pint_t secondLevelAddr =
1786	sects.compact_unwind_section + topIndex.secondLevelPagesSectionOffset(low);
1787	const pint_t lsdaArrayStartAddr =
1788	sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low);
1789	const pint_t lsdaArrayEndAddr =
1790	sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low+1);
1791	if (log)
1792	fprintf(stderr, "\tfirst level search for result index=%d "
1793	"to secondLevelAddr=0x%llX\n",
1794	low, (uint64_t) secondLevelAddr);
1795	// do a binary search of second level page index
1796	uint32_t encoding = 0;
1797	pint_t funcStart = 0;
1798	pint_t funcEnd = 0;
1799	pint_t lsda = 0;
1800	pint_t personality = 0;
1801	uint32_t pageKind = _addressSpace.get32(secondLevelAddr);
1802	if (pageKind == UNWIND_SECOND_LEVEL_REGULAR) {
1803	// regular page
1804	UnwindSectionRegularPageHeader<A> pageHeader(_addressSpace,
1805	secondLevelAddr);
1806	UnwindSectionRegularArray<A> pageIndex(
1807	_addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
1808	// binary search looks for entry with e where index[e].offset <= pc <
1809	// index[e+1].offset
1810	if (log)
1811	fprintf(stderr, "\tbinary search for targetFunctionOffset=0x%08llX in "
1812	"regular page starting at secondLevelAddr=0x%llX\n",
1813	(uint64_t) targetFunctionOffset, (uint64_t) secondLevelAddr);
1814	low = 0;
1815	high = pageHeader.entryCount();
1816	while (low < high) {
1817	uint32_t mid = (low + high) / 2;
1818	if (pageIndex.functionOffset(mid) <= targetFunctionOffset) {
1819	if (mid == (uint32_t)(pageHeader.entryCount() - 1)) {
1820	// at end of table
1821	low = mid;
1822	funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
1823	break;
1824	} else if (pageIndex.functionOffset(mid + 1) > targetFunctionOffset) {
1825	// next is too big, so we found it
1826	low = mid;
1827	funcEnd = pageIndex.functionOffset(low + 1) + sects.dso_base;
1828	break;
1829	} else {
1830	low = mid + 1;
1831	}
1832	} else {
1833	high = mid;
1834	}
1835	}
1836	encoding = pageIndex.encoding(low);
1837	funcStart = pageIndex.functionOffset(low) + sects.dso_base;
1838	if (pc < funcStart) {
1839	if (log)
1840	fprintf(
1841	stderr,
1842	"\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
1843	(uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
1844	return false;
1845	}
1846	if (pc > funcEnd) {
1847	if (log)
1848	fprintf(
1849	stderr,
1850	"\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
1851	(uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
1852	return false;
1853	}
1854	} else if (pageKind == UNWIND_SECOND_LEVEL_COMPRESSED) {
1855	// compressed page
1856	UnwindSectionCompressedPageHeader<A> pageHeader(_addressSpace,
1857	secondLevelAddr);
1858	UnwindSectionCompressedArray<A> pageIndex(
1859	_addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
1860	const uint32_t targetFunctionPageOffset =
1861	(uint32_t)(targetFunctionOffset - firstLevelFunctionOffset);
1862	// binary search looks for entry with e where index[e].offset <= pc <
1863	// index[e+1].offset
1864	if (log)
1865	fprintf(stderr, "\tbinary search of compressed page starting at "
1866	"secondLevelAddr=0x%llX\n",
1867	(uint64_t) secondLevelAddr);
1868	low = 0;
1869	last = pageHeader.entryCount() - 1;
1870	high = pageHeader.entryCount();
1871	while (low < high) {
1872	uint32_t mid = (low + high) / 2;
1873	if (pageIndex.functionOffset(mid) <= targetFunctionPageOffset) {
1874	if ((mid == last) ||
1875	(pageIndex.functionOffset(mid + 1) > targetFunctionPageOffset)) {
1876	low = mid;
1877	break;
1878	} else {
1879	low = mid + 1;
1880	}
1881	} else {
1882	high = mid;
1883	}
1884	}
1885	funcStart = pageIndex.functionOffset(low) + firstLevelFunctionOffset
1886	+ sects.dso_base;
1887	if (low < last)
1888	funcEnd =
1889	pageIndex.functionOffset(low + 1) + firstLevelFunctionOffset
1890	+ sects.dso_base;
1891	else
1892	funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
1893	if (pc < funcStart) {
1894	_LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX "
1895	"not in second level compressed unwind table. "
1896	"funcStart=0x%llX",
1897	(uint64_t) pc, (uint64_t) funcStart);
1898	return false;
1899	}
1900	if (pc > funcEnd) {
1901	_LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX "
1902	"not in second level compressed unwind table. "
1903	"funcEnd=0x%llX",
1904	(uint64_t) pc, (uint64_t) funcEnd);
1905	return false;
1906	}
1907	uint16_t encodingIndex = pageIndex.encodingIndex(low);
1908	if (encodingIndex < sectionHeader.commonEncodingsArrayCount()) {
1909	// encoding is in common table in section header
1910	encoding = _addressSpace.get32(
1911	sects.compact_unwind_section +
1912	sectionHeader.commonEncodingsArraySectionOffset() +
1913	encodingIndex * sizeof(uint32_t));
1914	} else {
1915	// encoding is in page specific table
1916	uint16_t pageEncodingIndex =
1917	encodingIndex - (uint16_t)sectionHeader.commonEncodingsArrayCount();
1918	encoding = _addressSpace.get32(secondLevelAddr +
1919	pageHeader.encodingsPageOffset() +
1920	pageEncodingIndex * sizeof(uint32_t));
1921	}
1922	} else {
1923	_LIBUNWIND_DEBUG_LOG(
1924	"malformed __unwind_info at 0x%0llX bad second level page",
1925	(uint64_t)sects.compact_unwind_section);
1926	return false;
1927	}
1928
1929	// look up LSDA, if encoding says function has one
1930	if (encoding & UNWIND_HAS_LSDA) {
1931	UnwindSectionLsdaArray<A> lsdaIndex(_addressSpace, lsdaArrayStartAddr);
1932	uint32_t funcStartOffset = (uint32_t)(funcStart - sects.dso_base);
1933	low = 0;
1934	high = (uint32_t)(lsdaArrayEndAddr - lsdaArrayStartAddr) /
1935	sizeof(unwind_info_section_header_lsda_index_entry);
1936	// binary search looks for entry with exact match for functionOffset
1937	if (log)
1938	fprintf(stderr,
1939	"\tbinary search of lsda table for targetFunctionOffset=0x%08X\n",
1940	funcStartOffset);
1941	while (low < high) {
1942	uint32_t mid = (low + high) / 2;
1943	if (lsdaIndex.functionOffset(mid) == funcStartOffset) {
1944	lsda = lsdaIndex.lsdaOffset(mid) + sects.dso_base;
1945	break;
1946	} else if (lsdaIndex.functionOffset(mid) < funcStartOffset) {
1947	low = mid + 1;
1948	} else {
1949	high = mid;
1950	}
1951	}
1952	if (lsda == 0) {
1953	_LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with HAS_LSDA bit set for "
1954	"pc=0x%0llX, but lsda table has no entry",
1955	encoding, (uint64_t) pc);
1956	return false;
1957	}
1958	}
1959
1960	// extract personality routine, if encoding says function has one
1961	uint32_t personalityIndex = (encoding & UNWIND_PERSONALITY_MASK) >>
1962	(__builtin_ctz(UNWIND_PERSONALITY_MASK));
1963	if (personalityIndex != 0) {
1964	--personalityIndex; // change 1-based to zero-based index
1965	if (personalityIndex >= sectionHeader.personalityArrayCount()) {
1966	_LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with personality index %d, "
1967	"but personality table has only %d entries",
1968	encoding, personalityIndex,
1969	sectionHeader.personalityArrayCount());
1970	return false;
1971	}
1972	int32_t personalityDelta = (int32_t)_addressSpace.get32(
1973	sects.compact_unwind_section +
1974	sectionHeader.personalityArraySectionOffset() +
1975	personalityIndex * sizeof(uint32_t));
1976	pint_t personalityPointer = sects.dso_base + (pint_t)personalityDelta;
1977	personality = _addressSpace.getP(personalityPointer);
1978	if (log)
1979	fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
1980	"personalityDelta=0x%08X, personality=0x%08llX\n",
1981	(uint64_t) pc, personalityDelta, (uint64_t) personality);
1982	}
1983
1984	if (log)
1985	fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
1986	"encoding=0x%08X, lsda=0x%08llX for funcStart=0x%llX\n",
1987	(uint64_t) pc, encoding, (uint64_t) lsda, (uint64_t) funcStart);
1988	_info.start_ip = funcStart;
1989	_info.end_ip = funcEnd;
1990	_info.lsda = lsda;
1991	_info.handler = personality;
1992	_info.gp = 0;
1993	_info.flags = 0;
1994	_info.format = encoding;
1995	_info.unwind_info = 0;
1996	_info.unwind_info_size = 0;
1997	_info.extra = sects.dso_base;
1998	return true;
1999	}
2000	#endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
2001
2002
2003	#if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
2004	template <typename A, typename R>
2005	bool UnwindCursor<A, R>::getInfoFromSEH(pint_t pc) {
2006	pint_t base;
2007	RUNTIME_FUNCTION *unwindEntry = lookUpSEHUnwindInfo(pc, &base);
2008	if (!unwindEntry) {
2009	_LIBUNWIND_DEBUG_LOG("\tpc not in table, pc=0x%llX", (uint64_t) pc);
2010	return false;
2011	}
2012	_info.gp = 0;
2013	_info.flags = 0;
2014	_info.format = 0;
2015	_info.unwind_info_size = sizeof(RUNTIME_FUNCTION);
2016	_info.unwind_info = reinterpret_cast<unw_word_t>(unwindEntry);
2017	_info.extra = base;
2018	_info.start_ip = base + unwindEntry->BeginAddress;
2019	#ifdef _LIBUNWIND_TARGET_X86_64
2020	_info.end_ip = base + unwindEntry->EndAddress;
2021	// Only fill in the handler and LSDA if they're stale.
2022	if (pc != getLastPC()) {
2023	UNWIND_INFO *xdata = reinterpret_cast<UNWIND_INFO *>(base + unwindEntry->UnwindData);
2024	if (xdata->Flags & (UNW_FLAG_EHANDLER|UNW_FLAG_UHANDLER)) {
2025	// The personality is given in the UNWIND_INFO itself. The LSDA immediately
2026	// follows the UNWIND_INFO. (This follows how both Clang and MSVC emit
2027	// these structures.)
2028	// N.B. UNWIND_INFO structs are DWORD-aligned.
2029	uint32_t lastcode = (xdata->CountOfCodes + 1) & ~1;
2030	const uint32_t *handler = reinterpret_cast<uint32_t *>(&xdata->UnwindCodes[lastcode]);
2031	_info.lsda = reinterpret_cast<unw_word_t>(handler+1);
2032	_dispContext.HandlerData = reinterpret_cast<void *>(_info.lsda);
2033	_dispContext.LanguageHandler =
2034	reinterpret_cast<EXCEPTION_ROUTINE *>(base + *handler);
2035	if (*handler) {
2036	_info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
2037	} else
2038	_info.handler = 0;
2039	} else {
2040	_info.lsda = 0;
2041	_info.handler = 0;
2042	}
2043	}
2044	#elif defined(_LIBUNWIND_TARGET_AARCH64) || defined(_LIBUNWIND_TARGET_ARM)
2045
2046	#if defined(_LIBUNWIND_TARGET_AARCH64)
2047	#define FUNC_LENGTH_UNIT 4
2048	#define XDATA_TYPE IMAGE_ARM64_RUNTIME_FUNCTION_ENTRY_XDATA
2049	#else
2050	#define FUNC_LENGTH_UNIT 2
2051	#define XDATA_TYPE UNWIND_INFO_ARM
2052	#endif
2053	if (unwindEntry->Flag != 0) { // Packed unwind info
2054	_info.end_ip =
2055	_info.start_ip + unwindEntry->FunctionLength * FUNC_LENGTH_UNIT;
2056	// Only fill in the handler and LSDA if they're stale.
2057	if (pc != getLastPC()) {
2058	// Packed unwind info doesn't have an exception handler.
2059	_info.lsda = 0;
2060	_info.handler = 0;
2061	}
2062	} else {
2063	XDATA_TYPE *xdata =
2064	reinterpret_cast<XDATA_TYPE *>(base + unwindEntry->UnwindData);
2065	_info.end_ip = _info.start_ip + xdata->FunctionLength * FUNC_LENGTH_UNIT;
2066	// Only fill in the handler and LSDA if they're stale.
2067	if (pc != getLastPC()) {
2068	if (xdata->ExceptionDataPresent) {
2069	uint32_t offset = 1; // The main xdata
2070	uint32_t codeWords = xdata->CodeWords;
2071	uint32_t epilogScopes = xdata->EpilogCount;
2072	if (xdata->EpilogCount == 0 && xdata->CodeWords == 0) {
2073	// The extension word has got the same layout for both ARM and ARM64
2074	uint32_t extensionWord = reinterpret_cast<uint32_t *>(xdata)[1];
2075	codeWords = (extensionWord >> 16) & 0xff;
2076	epilogScopes = extensionWord & 0xffff;
2077	offset++;
2078	}
2079	if (!xdata->EpilogInHeader)
2080	offset += epilogScopes;
2081	offset += codeWords;
2082	uint32_t *exceptionHandlerInfo =
2083	reinterpret_cast<uint32_t *>(xdata) + offset;
2084	_dispContext.HandlerData = &exceptionHandlerInfo[1];
2085	_dispContext.LanguageHandler = reinterpret_cast<EXCEPTION_ROUTINE *>(
2086	base + exceptionHandlerInfo[0]);
2087	_info.lsda = reinterpret_cast<unw_word_t>(_dispContext.HandlerData);
2088	if (exceptionHandlerInfo[0])
2089	_info.handler =
2090	reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
2091	else
2092	_info.handler = 0;
2093	} else {
2094	_info.lsda = 0;
2095	_info.handler = 0;
2096	}
2097	}
2098	}
2099	#endif
2100	setLastPC(pc);
2101	return true;
2102	}
2103	#endif
2104
2105	#if defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
2106	// Masks for traceback table field xtbtable.
2107	enum xTBTableMask : uint8_t {
2108	reservedBit = 0x02, // The traceback table was incorrectly generated if set
2109	// (see comments in function getInfoFromTBTable().
2110	ehInfoBit = 0x08 // Exception handling info is present if set
2111	};
2112
2113	enum frameType : unw_word_t {
2114	frameWithXLEHStateTable = 0,
2115	frameWithEHInfo = 1
2116	};
2117
2118	extern "C" {
2119	typedef _Unwind_Reason_Code __xlcxx_personality_v0_t(int, _Unwind_Action,
2120	uint64_t,
2121	_Unwind_Exception *,
2122	struct _Unwind_Context *);
2123	}
2124
2125	static __xlcxx_personality_v0_t *xlcPersonalityV0;
2126	static RWMutex xlcPersonalityV0InitLock;
2127
2128	template <typename A, typename R>
2129	bool UnwindCursor<A, R>::getInfoFromTBTable(pint_t pc, R &registers) {
2130	uint32_t *p = reinterpret_cast<uint32_t *>(pc);
2131
2132	// Keep looking forward until a word of 0 is found. The traceback
2133	// table starts at the following word.
2134	while (*p)
2135	++p;
2136	tbtable *TBTable = reinterpret_cast<tbtable *>(p + 1);
2137
2138	if (_LIBUNWIND_TRACING_UNWINDING) {
2139	char functionBuf[512];
2140	const char *functionName = functionBuf;
2141	unw_word_t offset;
2142	if (!getFunctionName(functionBuf, sizeof(functionBuf), &offset)) {
2143	functionName = ".anonymous.";
2144	}
2145	_LIBUNWIND_TRACE_UNWINDING("%s: Look up traceback table of func=%s at %p",
2146	__func__, functionName,
2147	reinterpret_cast<void *>(TBTable));
2148	}
2149
2150	// If the traceback table does not contain necessary info, bypass this frame.
2151	if (!TBTable->tb.has_tboff)
2152	return false;
2153
2154	// Structure tbtable_ext contains important data we are looking for.
2155	p = reinterpret_cast<uint32_t *>(&TBTable->tb_ext);
2156
2157	// Skip field parminfo if it exists.
2158	if (TBTable->tb.fixedparms || TBTable->tb.floatparms)
2159	++p;
2160
2161	// p now points to tb_offset, the offset from start of function to TB table.
2162	unw_word_t start_ip =
2163	reinterpret_cast<unw_word_t>(TBTable) - *p - sizeof(uint32_t);
2164	unw_word_t end_ip = reinterpret_cast<unw_word_t>(TBTable);
2165	++p;
2166
2167	_LIBUNWIND_TRACE_UNWINDING("start_ip=%p, end_ip=%p\n",
2168	reinterpret_cast<void *>(start_ip),
2169	reinterpret_cast<void *>(end_ip));
2170
2171	// Skip field hand_mask if it exists.
2172	if (TBTable->tb.int_hndl)
2173	++p;
2174
2175	unw_word_t lsda = 0;
2176	unw_word_t handler = 0;
2177	unw_word_t flags = frameType::frameWithXLEHStateTable;
2178
2179	if (TBTable->tb.lang == TB_CPLUSPLUS && TBTable->tb.has_ctl) {
2180	// State table info is available. The ctl_info field indicates the
2181	// number of CTL anchors. There should be only one entry for the C++
2182	// state table.
2183	assert(*p == 1 && "libunwind: there must be only one ctl_info entry");
2184	++p;
2185	// p points to the offset of the state table into the stack.
2186	pint_t stateTableOffset = *p++;
2187
2188	int framePointerReg;
2189
2190	// Skip fields name_len and name if exist.
2191	if (TBTable->tb.name_present) {
2192	const uint16_t name_len = *(reinterpret_cast<uint16_t *>(p));
2193	p = reinterpret_cast<uint32_t *>(reinterpret_cast<char *>(p) + name_len +
2194	sizeof(uint16_t));
2195	}
2196
2197	if (TBTable->tb.uses_alloca)
2198	framePointerReg = *(reinterpret_cast<char *>(p));
2199	else
2200	framePointerReg = 1; // default frame pointer == SP
2201
2202	_LIBUNWIND_TRACE_UNWINDING(
2203	"framePointerReg=%d, framePointer=%p, "
2204	"stateTableOffset=%#lx\n",
2205	framePointerReg,
2206	reinterpret_cast<void *>(_registers.getRegister(framePointerReg)),
2207	stateTableOffset);
2208	lsda = _registers.getRegister(framePointerReg) + stateTableOffset;
2209
2210	// Since the traceback table generated by the legacy XLC++ does not
2211	// provide the location of the personality for the state table,
2212	// function __xlcxx_personality_v0(), which is the personality for the state
2213	// table and is exported from libc++abi, is directly assigned as the
2214	// handler here. When a legacy XLC++ frame is encountered, the symbol
2215	// is resolved dynamically using dlopen() to avoid a hard dependency of
2216	// libunwind on libc++abi in cases such as non-C++ applications.
2217
2218	// Resolve the function pointer to the state table personality if it has
2219	// not already been done.
2220	if (xlcPersonalityV0 == NULL) {
2221	xlcPersonalityV0InitLock.lock();
2222	if (xlcPersonalityV0 == NULL) {
2223	// Resolve __xlcxx_personality_v0 using dlopen().
2224	const char *libcxxabi = "libc++abi.a(libc++abi.so.1)";
2225	void *libHandle;
2226	// The AIX dlopen() sets errno to 0 when it is successful, which
2227	// clobbers the value of errno from the user code. This is an AIX
2228	// bug because according to POSIX it should not set errno to 0. To
2229	// workaround before AIX fixes the bug, errno is saved and restored.
2230	int saveErrno = errno;
2231	libHandle = dlopen(libcxxabi, RTLD_MEMBER | RTLD_NOW);
2232	if (libHandle == NULL) {
2233	_LIBUNWIND_TRACE_UNWINDING("dlopen() failed with errno=%d\n", errno);
2234	assert(0 && "dlopen() failed");
2235	}
2236	xlcPersonalityV0 = reinterpret_cast<__xlcxx_personality_v0_t *>(
2237	dlsym(libHandle, "__xlcxx_personality_v0"));
2238	if (xlcPersonalityV0 == NULL) {
2239	_LIBUNWIND_TRACE_UNWINDING("dlsym() failed with errno=%d\n", errno);
2240	dlclose(libHandle);
2241	assert(0 && "dlsym() failed");
2242	}
2243	errno = saveErrno;
2244	}
2245	xlcPersonalityV0InitLock.unlock();
2246	}
2247	handler = reinterpret_cast<unw_word_t>(xlcPersonalityV0);
2248	_LIBUNWIND_TRACE_UNWINDING("State table: LSDA=%p, Personality=%p\n",
2249	reinterpret_cast<void *>(lsda),
2250	reinterpret_cast<void *>(handler));
2251	} else if (TBTable->tb.longtbtable) {
2252	// This frame has the traceback table extension. Possible cases are
2253	// 1) a C++ frame that has the 'eh_info' structure; 2) a C++ frame that
2254	// is not EH aware; or, 3) a frame of other languages. We need to figure out
2255	// if the traceback table extension contains the 'eh_info' structure.
2256	//
2257	// We also need to deal with the complexity arising from some XL compiler
2258	// versions use the wrong ordering of 'longtbtable' and 'has_vec' bits
2259	// where the 'longtbtable' bit is meant to be the 'has_vec' bit and vice
2260	// versa. For frames of code generated by those compilers, the 'longtbtable'
2261	// bit may be set but there isn't really a traceback table extension.
2262	//
2263	// In </usr/include/sys/debug.h>, there is the following definition of
2264	// 'struct tbtable_ext'. It is not really a structure but a dummy to
2265	// collect the description of optional parts of the traceback table.
2266	//
2267	// struct tbtable_ext {
2268	// ...
2269	// char alloca_reg; /* Register for alloca automatic storage */
2270	// struct vec_ext vec_ext; /* Vector extension (if has_vec is set) */
2271	// unsigned char xtbtable; /* More tbtable fields, if longtbtable is set*/
2272	// };
2273	//
2274	// Depending on how the 'has_vec'/'longtbtable' bit is interpreted, the data
2275	// following 'alloca_reg' can be treated either as 'struct vec_ext' or
2276	// 'unsigned char xtbtable'. 'xtbtable' bits are defined in
2277	// </usr/include/sys/debug.h> as flags. The 7th bit '0x02' is currently
2278	// unused and should not be set. 'struct vec_ext' is defined in
2279	// </usr/include/sys/debug.h> as follows:
2280	//
2281	// struct vec_ext {
2282	// unsigned vr_saved:6; /* Number of non-volatile vector regs saved
2283	// */
2284	// /* first register saved is assumed to be */
2285	// /* 32 - vr_saved */
2286	// unsigned saves_vrsave:1; /* Set if vrsave is saved on the stack */
2287	// unsigned has_varargs:1;
2288	// ...
2289	// };
2290	//
2291	// Here, the 7th bit is used as 'saves_vrsave'. To determine whether it
2292	// is 'struct vec_ext' or 'xtbtable' that follows 'alloca_reg',
2293	// we checks if the 7th bit is set or not because 'xtbtable' should
2294	// never have the 7th bit set. The 7th bit of 'xtbtable' will be reserved
2295	// in the future to make sure the mitigation works. This mitigation
2296	// is not 100% bullet proof because 'struct vec_ext' may not always have
2297	// 'saves_vrsave' bit set.
2298	//
2299	// 'reservedBit' is defined in enum 'xTBTableMask' above as the mask for
2300	// checking the 7th bit.
2301
2302	// p points to field name len.
2303	uint8_t *charPtr = reinterpret_cast<uint8_t *>(p);
2304
2305	// Skip fields name_len and name if they exist.
2306	if (TBTable->tb.name_present) {
2307	const uint16_t name_len = *(reinterpret_cast<uint16_t *>(charPtr));
2308	charPtr = charPtr + name_len + sizeof(uint16_t);
2309	}
2310
2311	// Skip field alloc_reg if it exists.
2312	if (TBTable->tb.uses_alloca)
2313	++charPtr;
2314
2315	// Check traceback table bit has_vec. Skip struct vec_ext if it exists.
2316	if (TBTable->tb.has_vec)
2317	// Note struct vec_ext does exist at this point because whether the
2318	// ordering of longtbtable and has_vec bits is correct or not, both
2319	// are set.
2320	charPtr += sizeof(struct vec_ext);
2321
2322	// charPtr points to field 'xtbtable'. Check if the EH info is available.
2323	// Also check if the reserved bit of the extended traceback table field
2324	// 'xtbtable' is set. If it is, the traceback table was incorrectly
2325	// generated by an XL compiler that uses the wrong ordering of 'longtbtable'
2326	// and 'has_vec' bits and this is in fact 'struct vec_ext'. So skip the
2327	// frame.
2328	if ((*charPtr & xTBTableMask::ehInfoBit) &&
2329	!(*charPtr & xTBTableMask::reservedBit)) {
2330	// Mark this frame has the new EH info.
2331	flags = frameType::frameWithEHInfo;
2332
2333	// eh_info is available.
2334	charPtr++;
2335	// The pointer is 4-byte aligned.
2336	if (reinterpret_cast<uintptr_t>(charPtr) % 4)
2337	charPtr += 4 - reinterpret_cast<uintptr_t>(charPtr) % 4;
2338	uintptr_t *ehInfo =
2339	reinterpret_cast<uintptr_t *>(*(reinterpret_cast<uintptr_t *>(
2340	registers.getRegister(2) +
2341	*(reinterpret_cast<uintptr_t *>(charPtr)))));
2342
2343	// ehInfo points to structure en_info. The first member is version.
2344	// Only version 0 is currently supported.
2345	assert(*(reinterpret_cast<uint32_t *>(ehInfo)) == 0 &&
2346	"libunwind: ehInfo version other than 0 is not supported");
2347
2348	// Increment ehInfo to point to member lsda.
2349	++ehInfo;
2350	lsda = *ehInfo++;
2351
2352	// enInfo now points to member personality.
2353	handler = *ehInfo;
2354
2355	_LIBUNWIND_TRACE_UNWINDING("Range table: LSDA=%#lx, Personality=%#lx\n",
2356	lsda, handler);
2357	}
2358	}
2359
2360	_info.start_ip = start_ip;
2361	_info.end_ip = end_ip;
2362	_info.lsda = lsda;
2363	_info.handler = handler;
2364	_info.gp = 0;
2365	_info.flags = flags;
2366	_info.format = 0;
2367	_info.unwind_info = reinterpret_cast<unw_word_t>(TBTable);
2368	_info.unwind_info_size = 0;
2369	_info.extra = registers.getRegister(2);
2370
2371	return true;
2372	}
2373
2374	// Step back up the stack following the frame back link.
2375	template <typename A, typename R>
2376	int UnwindCursor<A, R>::stepWithTBTable(pint_t pc, tbtable *TBTable,
2377	R &registers, bool &isSignalFrame) {
2378	if (_LIBUNWIND_TRACING_UNWINDING) {
2379	char functionBuf[512];
2380	const char *functionName = functionBuf;
2381	unw_word_t offset;
2382	if (!getFunctionName(functionBuf, sizeof(functionBuf), &offset)) {
2383	functionName = ".anonymous.";
2384	}
2385	_LIBUNWIND_TRACE_UNWINDING(
2386	"%s: Look up traceback table of func=%s at %p, pc=%p, "
2387	"SP=%p, saves_lr=%d, stores_bc=%d",
2388	__func__, functionName, reinterpret_cast<void *>(TBTable),
2389	reinterpret_cast<void *>(pc),
2390	reinterpret_cast<void *>(registers.getSP()), TBTable->tb.saves_lr,
2391	TBTable->tb.stores_bc);
2392	}
2393
2394	#if defined(__powerpc64__)
2395	// Instruction to reload TOC register "ld r2,40(r1)"
2396	const uint32_t loadTOCRegInst = 0xe8410028;
2397	const int32_t unwPPCF0Index = UNW_PPC64_F0;
2398	const int32_t unwPPCV0Index = UNW_PPC64_V0;
2399	#else
2400	// Instruction to reload TOC register "lwz r2,20(r1)"
2401	const uint32_t loadTOCRegInst = 0x80410014;
2402	const int32_t unwPPCF0Index = UNW_PPC_F0;
2403	const int32_t unwPPCV0Index = UNW_PPC_V0;
2404	#endif
2405
2406	// lastStack points to the stack frame of the next routine up.
2407	pint_t curStack = static_cast<pint_t>(registers.getSP());
2408	pint_t lastStack = *reinterpret_cast<pint_t *>(curStack);
2409
2410	if (lastStack == 0)
2411	return UNW_STEP_END;
2412
2413	R newRegisters = registers;
2414
2415	// If backchain is not stored, use the current stack frame.
2416	if (!TBTable->tb.stores_bc)
2417	lastStack = curStack;
2418
2419	// Return address is the address after call site instruction.
2420	pint_t returnAddress;
2421
2422	if (isSignalFrame) {
2423	_LIBUNWIND_TRACE_UNWINDING("Possible signal handler frame: lastStack=%p",
2424	reinterpret_cast<void *>(lastStack));
2425
2426	sigcontext *sigContext = reinterpret_cast<sigcontext *>(
2427	reinterpret_cast<char *>(lastStack) + STKMINALIGN);
2428	returnAddress = sigContext->sc_jmpbuf.jmp_context.iar;
2429
2430	bool useSTKMIN = false;
2431	if (returnAddress < 0x10000000) {
2432	// Try again using STKMIN.
2433	sigContext = reinterpret_cast<sigcontext *>(
2434	reinterpret_cast<char *>(lastStack) + STKMIN);
2435	returnAddress = sigContext->sc_jmpbuf.jmp_context.iar;
2436	if (returnAddress < 0x10000000) {
2437	_LIBUNWIND_TRACE_UNWINDING("Bad returnAddress=%p from sigcontext=%p",
2438	reinterpret_cast<void *>(returnAddress),
2439	reinterpret_cast<void *>(sigContext));
2440	return UNW_EBADFRAME;
2441	}
2442	useSTKMIN = true;
2443	}
2444	_LIBUNWIND_TRACE_UNWINDING("Returning from a signal handler %s: "
2445	"sigContext=%p, returnAddress=%p. "
2446	"Seems to be a valid address",
2447	useSTKMIN ? "STKMIN" : "STKMINALIGN",
2448	reinterpret_cast<void *>(sigContext),
2449	reinterpret_cast<void *>(returnAddress));
2450
2451	// Restore the condition register from sigcontext.
2452	newRegisters.setCR(sigContext->sc_jmpbuf.jmp_context.cr);
2453
2454	// Save the LR in sigcontext for stepping up when the function that
2455	// raised the signal is a leaf function. This LR has the return address
2456	// to the caller of the leaf function.
2457	newRegisters.setLR(sigContext->sc_jmpbuf.jmp_context.lr);
2458	_LIBUNWIND_TRACE_UNWINDING(
2459	"Save LR=%p from sigcontext",
2460	reinterpret_cast<void *>(sigContext->sc_jmpbuf.jmp_context.lr));
2461
2462	// Restore GPRs from sigcontext.
2463	for (int i = 0; i < 32; ++i)
2464	newRegisters.setRegister(i, sigContext->sc_jmpbuf.jmp_context.gpr[i]);
2465
2466	// Restore FPRs from sigcontext.
2467	for (int i = 0; i < 32; ++i)
2468	newRegisters.setFloatRegister(i + unwPPCF0Index,
2469	sigContext->sc_jmpbuf.jmp_context.fpr[i]);
2470
2471	// Restore vector registers if there is an associated extended context
2472	// structure.
2473	if (sigContext->sc_jmpbuf.jmp_context.msr & __EXTCTX) {
2474	ucontext_t *uContext = reinterpret_cast<ucontext_t *>(sigContext);
2475	if (uContext->__extctx->__extctx_magic == __EXTCTX_MAGIC) {
2476	for (int i = 0; i < 32; ++i)
2477	newRegisters.setVectorRegister(
2478	i + unwPPCV0Index, *(reinterpret_cast<v128 *>(
2479	&(uContext->__extctx->__vmx.__vr[i]))));
2480	}
2481	}
2482	} else {
2483	// Step up a normal frame.
2484
2485	if (!TBTable->tb.saves_lr && registers.getLR()) {
2486	// This case should only occur if we were called from a signal handler
2487	// and the signal occurred in a function that doesn't save the LR.
2488	returnAddress = static_cast<pint_t>(registers.getLR());
2489	_LIBUNWIND_TRACE_UNWINDING("Use saved LR=%p",
2490	reinterpret_cast<void *>(returnAddress));
2491	} else {
2492	// Otherwise, use the LR value in the stack link area.
2493	returnAddress = reinterpret_cast<pint_t *>(lastStack)[2];
2494	}
2495
2496	// Reset LR in the current context.
2497	newRegisters.setLR(static_cast<uintptr_t>(NULL));
2498
2499	_LIBUNWIND_TRACE_UNWINDING(
2500	"Extract info from lastStack=%p, returnAddress=%p",
2501	reinterpret_cast<void *>(lastStack),
2502	reinterpret_cast<void *>(returnAddress));
2503	_LIBUNWIND_TRACE_UNWINDING("fpr_regs=%d, gpr_regs=%d, saves_cr=%d",
2504	TBTable->tb.fpr_saved, TBTable->tb.gpr_saved,
2505	TBTable->tb.saves_cr);
2506
2507	// Restore FP registers.
2508	char *ptrToRegs = reinterpret_cast<char *>(lastStack);
2509	double *FPRegs = reinterpret_cast<double *>(
2510	ptrToRegs - (TBTable->tb.fpr_saved * sizeof(double)));
2511	for (int i = 0; i < TBTable->tb.fpr_saved; ++i)
2512	newRegisters.setFloatRegister(
2513	32 - TBTable->tb.fpr_saved + i + unwPPCF0Index, FPRegs[i]);
2514
2515	// Restore GP registers.
2516	ptrToRegs = reinterpret_cast<char *>(FPRegs);
2517	uintptr_t *GPRegs = reinterpret_cast<uintptr_t *>(
2518	ptrToRegs - (TBTable->tb.gpr_saved * sizeof(uintptr_t)));
2519	for (int i = 0; i < TBTable->tb.gpr_saved; ++i)
2520	newRegisters.setRegister(32 - TBTable->tb.gpr_saved + i, GPRegs[i]);
2521
2522	// Restore Vector registers.
2523	ptrToRegs = reinterpret_cast<char *>(GPRegs);
2524
2525	// Restore vector registers only if this is a Clang frame. Also
2526	// check if traceback table bit has_vec is set. If it is, structure
2527	// vec_ext is available.
2528	if (_info.flags == frameType::frameWithEHInfo && TBTable->tb.has_vec) {
2529
2530	// Get to the vec_ext structure to check if vector registers are saved.
2531	uint32_t *p = reinterpret_cast<uint32_t *>(&TBTable->tb_ext);
2532
2533	// Skip field parminfo if exists.
2534	if (TBTable->tb.fixedparms || TBTable->tb.floatparms)
2535	++p;
2536
2537	// Skip field tb_offset if exists.
2538	if (TBTable->tb.has_tboff)
2539	++p;
2540
2541	// Skip field hand_mask if exists.
2542	if (TBTable->tb.int_hndl)
2543	++p;
2544
2545	// Skip fields ctl_info and ctl_info_disp if exist.
2546	if (TBTable->tb.has_ctl) {
2547	// Skip field ctl_info.
2548	++p;
2549	// Skip field ctl_info_disp.
2550	++p;
2551	}
2552
2553	// Skip fields name_len and name if exist.
2554	// p is supposed to point to field name_len now.
2555	uint8_t *charPtr = reinterpret_cast<uint8_t *>(p);
2556	if (TBTable->tb.name_present) {
2557	const uint16_t name_len = *(reinterpret_cast<uint16_t *>(charPtr));
2558	charPtr = charPtr + name_len + sizeof(uint16_t);
2559	}
2560
2561	// Skip field alloc_reg if it exists.
2562	if (TBTable->tb.uses_alloca)
2563	++charPtr;
2564
2565	struct vec_ext *vec_ext = reinterpret_cast<struct vec_ext *>(charPtr);
2566
2567	_LIBUNWIND_TRACE_UNWINDING("vr_saved=%d", vec_ext->vr_saved);
2568
2569	// Restore vector register(s) if saved on the stack.
2570	if (vec_ext->vr_saved) {
2571	// Saved vector registers are 16-byte aligned.
2572	if (reinterpret_cast<uintptr_t>(ptrToRegs) % 16)
2573	ptrToRegs -= reinterpret_cast<uintptr_t>(ptrToRegs) % 16;
2574	v128 *VecRegs = reinterpret_cast<v128 *>(ptrToRegs - vec_ext->vr_saved *
2575	sizeof(v128));
2576	for (int i = 0; i < vec_ext->vr_saved; ++i) {
2577	newRegisters.setVectorRegister(
2578	32 - vec_ext->vr_saved + i + unwPPCV0Index, VecRegs[i]);
2579	}
2580	}
2581	}
2582	if (TBTable->tb.saves_cr) {
2583	// Get the saved condition register. The condition register is only
2584	// a single word.
2585	newRegisters.setCR(
2586	*(reinterpret_cast<uint32_t *>(lastStack + sizeof(uintptr_t))));
2587	}
2588
2589	// Restore the SP.
2590	newRegisters.setSP(lastStack);
2591
2592	// The first instruction after return.
2593	uint32_t firstInstruction = *(reinterpret_cast<uint32_t *>(returnAddress));
2594
2595	// Do we need to set the TOC register?
2596	_LIBUNWIND_TRACE_UNWINDING(
2597	"Current gpr2=%p",
2598	reinterpret_cast<void *>(newRegisters.getRegister(2)));
2599	if (firstInstruction == loadTOCRegInst) {
2600	_LIBUNWIND_TRACE_UNWINDING(
2601	"Set gpr2=%p from frame",
2602	reinterpret_cast<void *>(reinterpret_cast<pint_t *>(lastStack)[5]));
2603	newRegisters.setRegister(2, reinterpret_cast<pint_t *>(lastStack)[5]);
2604	}
2605	}
2606	_LIBUNWIND_TRACE_UNWINDING("lastStack=%p, returnAddress=%p, pc=%p\n",
2607	reinterpret_cast<void *>(lastStack),
2608	reinterpret_cast<void *>(returnAddress),
2609	reinterpret_cast<void *>(pc));
2610
2611	// The return address is the address after call site instruction, so
2612	// setting IP to that simulates a return.
2613	newRegisters.setIP(reinterpret_cast<uintptr_t>(returnAddress));
2614
2615	// Simulate the step by replacing the register set with the new ones.
2616	registers = newRegisters;
2617
2618	// Check if the next frame is a signal frame.
2619	pint_t nextStack = *(reinterpret_cast<pint_t *>(registers.getSP()));
2620
2621	// Return address is the address after call site instruction.
2622	pint_t nextReturnAddress = reinterpret_cast<pint_t *>(nextStack)[2];
2623
2624	if (nextReturnAddress > 0x01 && nextReturnAddress < 0x10000) {
2625	_LIBUNWIND_TRACE_UNWINDING("The next is a signal handler frame: "
2626	"nextStack=%p, next return address=%p\n",
2627	reinterpret_cast<void *>(nextStack),
2628	reinterpret_cast<void *>(nextReturnAddress));
2629	isSignalFrame = true;
2630	} else {
2631	isSignalFrame = false;
2632	}
2633	return UNW_STEP_SUCCESS;
2634	}
2635	#endif // defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
2636
2637	template <typename A, typename R>
2638	void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
2639	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) || \
2640	defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
2641	_isSigReturn = false;
2642	#endif
2643
2644	pint_t pc = static_cast<pint_t>(this->getReg(regNum: UNW_REG_IP));
2645	#if defined(_LIBUNWIND_ARM_EHABI)
2646	// Remove the thumb bit so the IP represents the actual instruction address.
2647	// This matches the behaviour of _Unwind_GetIP on arm.
2648	pc &= (pint_t)~0x1;
2649	#endif
2650
2651	// Exit early if at the top of the stack.
2652	if (pc == 0) {
2653	_unwindInfoMissing = true;
2654	return;
2655	}
2656
2657	// If the last line of a function is a "throw" the compiler sometimes
2658	// emits no instructions after the call to __cxa_throw. This means
2659	// the return address is actually the start of the next function.
2660	// To disambiguate this, back up the pc when we know it is a return
2661	// address.
2662	if (isReturnAddress)
2663	#if defined(_AIX)
2664	// PC needs to be a 4-byte aligned address to be able to look for a
2665	// word of 0 that indicates the start of the traceback table at the end
2666	// of a function on AIX.
2667	pc -= 4;
2668	#else
2669	--pc;
2670	#endif
2671
2672	#if !(defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)) && \
2673	!defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
2674	// In case of this is frame of signal handler, the IP saved in the signal
2675	// handler points to first non-executed instruction, while FDE/CIE expects IP
2676	// to be after the first non-executed instruction.
2677	if (_isSignalFrame)
2678	++pc;
2679	#endif
2680
2681	// Ask address space object to find unwind sections for this pc.
2682	UnwindInfoSections sects;
2683	if (_addressSpace.findUnwindSections(pc, sects)) {
2684	#if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
2685	// If there is a compact unwind encoding table, look there first.
2686	if (sects.compact_unwind_section != 0) {
2687	if (this->getInfoFromCompactEncodingSection(pc, sects)) {
2688	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
2689	// Found info in table, done unless encoding says to use dwarf.
2690	uint32_t dwarfOffset;
2691	if ((sects.dwarf_section != 0) && compactSaysUseDwarf(&dwarfOffset)) {
2692	if (this->getInfoFromDwarfSection(pc, sects, dwarfOffset)) {
2693	// found info in dwarf, done
2694	return;
2695	}
2696	}
2697	#endif
2698	// If unwind table has entry, but entry says there is no unwind info,
2699	// record that we have no unwind info.
2700	if (_info.format == 0)
2701	_unwindInfoMissing = true;
2702	return;
2703	}
2704	}
2705	#endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
2706
2707	#if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
2708	// If there is SEH unwind info, look there next.
2709	if (this->getInfoFromSEH(pc))
2710	return;
2711	#endif
2712
2713	#if defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
2714	// If there is unwind info in the traceback table, look there next.
2715	if (this->getInfoFromTBTable(pc, _registers))
2716	return;
2717	#endif
2718
2719	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
2720	// If there is dwarf unwind info, look there next.
2721	if (sects.dwarf_section != 0) {
2722	if (this->getInfoFromDwarfSection(pc, sects)) {
2723	// found info in dwarf, done
2724	return;
2725	}
2726	}
2727	#endif
2728
2729	#if defined(_LIBUNWIND_ARM_EHABI)
2730	// If there is ARM EHABI unwind info, look there next.
2731	if (sects.arm_section != 0 && this->getInfoFromEHABISection(pc, sects))
2732	return;
2733	#endif
2734	}
2735
2736	#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
2737	// There is no static unwind info for this pc. Look to see if an FDE was
2738	// dynamically registered for it.
2739	pint_t cachedFDE = DwarfFDECache<A>::findFDE(DwarfFDECache<A>::kSearchAll,
2740	pc);
2741	if (cachedFDE != 0) {
2742	typename CFI_Parser<A>::FDE_Info fdeInfo;
2743	typename CFI_Parser<A>::CIE_Info cieInfo;
2744	if (!CFI_Parser<A>::decodeFDE(_addressSpace, cachedFDE, &fdeInfo, &cieInfo))
2745	if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, dso_base: 0))
2746	return;
2747	}
2748
2749	// Lastly, ask AddressSpace object about platform specific ways to locate
2750	// other FDEs.
2751	pint_t fde;
2752	if (_addressSpace.findOtherFDE(pc, fde)) {
2753	typename CFI_Parser<A>::FDE_Info fdeInfo;
2754	typename CFI_Parser<A>::CIE_Info cieInfo;
2755	if (!CFI_Parser<A>::decodeFDE(_addressSpace, fde, &fdeInfo, &cieInfo)) {
2756	// Double check this FDE is for a function that includes the pc.
2757	if ((fdeInfo.pcStart <= pc) && (pc < fdeInfo.pcEnd))
2758	if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, dso_base: 0))
2759	return;
2760	}
2761	}
2762	#endif // #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
2763
2764	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) || \
2765	defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
2766	if (setInfoForSigReturn())
2767	return;
2768	#endif
2769
2770	// no unwind info, flag that we can't reliably unwind
2771	_unwindInfoMissing = true;
2772	}
2773
2774	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) && \
2775	defined(_LIBUNWIND_TARGET_AARCH64)
2776	template <typename A, typename R>
2777	bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_arm64 &) {
2778	// Look for the sigreturn trampoline. The trampoline's body is two
2779	// specific instructions (see below). Typically the trampoline comes from the
2780	// vDSO[1] (i.e. the __kernel_rt_sigreturn function). A libc might provide its
2781	// own restorer function, though, or user-mode QEMU might write a trampoline
2782	// onto the stack.
2783	//
2784	// This special code path is a fallback that is only used if the trampoline
2785	// lacks proper (e.g. DWARF) unwind info. On AArch64, a new DWARF register
2786	// constant for the PC needs to be defined before DWARF can handle a signal
2787	// trampoline. This code may segfault if the target PC is unreadable, e.g.:
2788	// - The PC points at a function compiled without unwind info, and which is
2789	// part of an execute-only mapping (e.g. using -Wl,--execute-only).
2790	// - The PC is invalid and happens to point to unreadable or unmapped memory.
2791	//
2792	// [1] https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/vdso/sigreturn.S
2793	const pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
2794	// The PC might contain an invalid address if the unwind info is bad, so
2795	// directly accessing it could cause a SIGSEGV.
2796	if (!isReadableAddr(pc))
2797	return false;
2798	auto *instructions = reinterpret_cast<const uint32_t *>(pc);
2799	// Look for instructions: mov x8, #0x8b; svc #0x0
2800	if (instructions[0] != 0xd2801168 || instructions[1] != 0xd4000001)
2801	return false;
2802
2803	_info = {};
2804	_info.start_ip = pc;
2805	_info.end_ip = pc + 4;
2806	_isSigReturn = true;
2807	return true;
2808	}
2809
2810	template <typename A, typename R>
2811	int UnwindCursor<A, R>::stepThroughSigReturn(Registers_arm64 &) {
2812	// In the signal trampoline frame, sp points to an rt_sigframe[1], which is:
2813	// - 128-byte siginfo struct
2814	// - ucontext struct:
2815	// - 8-byte long (uc_flags)
2816	// - 8-byte pointer (uc_link)
2817	// - 24-byte stack_t
2818	// - 128-byte signal set
2819	// - 8 bytes of padding because sigcontext has 16-byte alignment
2820	// - sigcontext/mcontext_t
2821	// [1] https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/signal.c
2822	const pint_t kOffsetSpToSigcontext = (128 + 8 + 8 + 24 + 128 + 8); // 304
2823
2824	// Offsets from sigcontext to each register.
2825	const pint_t kOffsetGprs = 8; // offset to "__u64 regs[31]" field
2826	const pint_t kOffsetSp = 256; // offset to "__u64 sp" field
2827	const pint_t kOffsetPc = 264; // offset to "__u64 pc" field
2828
2829	pint_t sigctx = _registers.getSP() + kOffsetSpToSigcontext;
2830
2831	for (int i = 0; i <= 30; ++i) {
2832	uint64_t value = _addressSpace.get64(sigctx + kOffsetGprs +
2833	static_cast<pint_t>(i * 8));
2834	_registers.setRegister(UNW_AARCH64_X0 + i, value);
2835	}
2836	_registers.setSP(_addressSpace.get64(sigctx + kOffsetSp));
2837	_registers.setIP(_addressSpace.get64(sigctx + kOffsetPc));
2838	_isSignalFrame = true;
2839	return UNW_STEP_SUCCESS;
2840	}
2841	#endif // defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) &&
2842	// defined(_LIBUNWIND_TARGET_AARCH64)
2843
2844	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) && \
2845	defined(_LIBUNWIND_TARGET_LOONGARCH)
2846	template <typename A, typename R>
2847	bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_loongarch &) {
2848	const pint_t pc = static_cast<pint_t>(getReg(UNW_REG_IP));
2849	// The PC might contain an invalid address if the unwind info is bad, so
2850	// directly accessing it could cause a SIGSEGV.
2851	if (!isReadableAddr(pc))
2852	return false;
2853	const auto *instructions = reinterpret_cast<const uint32_t *>(pc);
2854	// Look for the two instructions used in the sigreturn trampoline
2855	// __vdso_rt_sigreturn:
2856	//
2857	// 0x03822c0b li a7,0x8b
2858	// 0x002b0000 syscall 0
2859	if (instructions[0] != 0x03822c0b || instructions[1] != 0x002b0000)
2860	return false;
2861
2862	_info = {};
2863	_info.start_ip = pc;
2864	_info.end_ip = pc + 4;
2865	_isSigReturn = true;
2866	return true;
2867	}
2868
2869	template <typename A, typename R>
2870	int UnwindCursor<A, R>::stepThroughSigReturn(Registers_loongarch &) {
2871	// In the signal trampoline frame, sp points to an rt_sigframe[1], which is:
2872	// - 128-byte siginfo struct
2873	// - ucontext_t struct:
2874	// - 8-byte long (__uc_flags)
2875	// - 8-byte pointer (*uc_link)
2876	// - 24-byte uc_stack
2877	// - 8-byte uc_sigmask
2878	// - 120-byte of padding to allow sigset_t to be expanded in the future
2879	// - 8 bytes of padding because sigcontext has 16-byte alignment
2880	// - struct sigcontext uc_mcontext
2881	// [1]
2882	// https://github.com/torvalds/linux/blob/master/arch/loongarch/kernel/signal.c
2883	const pint_t kOffsetSpToSigcontext = 128 + 8 + 8 + 24 + 8 + 128;
2884
2885	const pint_t sigctx = _registers.getSP() + kOffsetSpToSigcontext;
2886	_registers.setIP(_addressSpace.get64(sigctx));
2887	for (int i = UNW_LOONGARCH_R1; i <= UNW_LOONGARCH_R31; ++i) {
2888	// skip R0
2889	uint64_t value =
2890	_addressSpace.get64(sigctx + static_cast<pint_t>((i + 1) * 8));
2891	_registers.setRegister(i, value);
2892	}
2893	_isSignalFrame = true;
2894	return UNW_STEP_SUCCESS;
2895	}
2896	#endif // defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) &&
2897	// defined(_LIBUNWIND_TARGET_LOONGARCH)
2898
2899	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) && \
2900	defined(_LIBUNWIND_TARGET_RISCV)
2901	template <typename A, typename R>
2902	bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_riscv &) {
2903	const pint_t pc = static_cast<pint_t>(getReg(UNW_REG_IP));
2904	// The PC might contain an invalid address if the unwind info is bad, so
2905	// directly accessing it could cause a SIGSEGV.
2906	if (!isReadableAddr(pc))
2907	return false;
2908	const auto *instructions = reinterpret_cast<const uint32_t *>(pc);
2909	// Look for the two instructions used in the sigreturn trampoline
2910	// __vdso_rt_sigreturn:
2911	//
2912	// 0x08b00893 li a7,0x8b
2913	// 0x00000073 ecall
2914	if (instructions[0] != 0x08b00893 || instructions[1] != 0x00000073)
2915	return false;
2916
2917	_info = {};
2918	_info.start_ip = pc;
2919	_info.end_ip = pc + 4;
2920	_isSigReturn = true;
2921	return true;
2922	}
2923
2924	template <typename A, typename R>
2925	int UnwindCursor<A, R>::stepThroughSigReturn(Registers_riscv &) {
2926	// In the signal trampoline frame, sp points to an rt_sigframe[1], which is:
2927	// - 128-byte siginfo struct
2928	// - ucontext_t struct:
2929	// - 8-byte long (__uc_flags)
2930	// - 8-byte pointer (*uc_link)
2931	// - 24-byte uc_stack
2932	// - 8-byte uc_sigmask
2933	// - 120-byte of padding to allow sigset_t to be expanded in the future
2934	// - 8 bytes of padding because sigcontext has 16-byte alignment
2935	// - struct sigcontext uc_mcontext
2936	// [1]
2937	// https://github.com/torvalds/linux/blob/master/arch/riscv/kernel/signal.c
2938	const pint_t kOffsetSpToSigcontext = 128 + 8 + 8 + 24 + 8 + 128;
2939
2940	const pint_t sigctx = _registers.getSP() + kOffsetSpToSigcontext;
2941	_registers.setIP(_addressSpace.get64(sigctx));
2942	for (int i = UNW_RISCV_X1; i <= UNW_RISCV_X31; ++i) {
2943	uint64_t value = _addressSpace.get64(sigctx + static_cast<pint_t>(i * 8));
2944	_registers.setRegister(i, value);
2945	}
2946	_isSignalFrame = true;
2947	return UNW_STEP_SUCCESS;
2948	}
2949	#endif // defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) &&
2950	// defined(_LIBUNWIND_TARGET_RISCV)
2951
2952	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) && \
2953	defined(_LIBUNWIND_TARGET_S390X)
2954	template <typename A, typename R>
2955	bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_s390x &) {
2956	// Look for the sigreturn trampoline. The trampoline's body is a
2957	// specific instruction (see below). Typically the trampoline comes from the
2958	// vDSO (i.e. the __kernel_[rt_]sigreturn function). A libc might provide its
2959	// own restorer function, though, or user-mode QEMU might write a trampoline
2960	// onto the stack.
2961	const pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
2962	// The PC might contain an invalid address if the unwind info is bad, so
2963	// directly accessing it could cause a SIGSEGV.
2964	if (!isReadableAddr(pc))
2965	return false;
2966	const auto inst = *reinterpret_cast<const uint16_t *>(pc);
2967	if (inst == 0x0a77 || inst == 0x0aad) {
2968	_info = {};
2969	_info.start_ip = pc;
2970	_info.end_ip = pc + 2;
2971	_isSigReturn = true;
2972	return true;
2973	}
2974	return false;
2975	}
2976
2977	template <typename A, typename R>
2978	int UnwindCursor<A, R>::stepThroughSigReturn(Registers_s390x &) {
2979	// Determine current SP.
2980	const pint_t sp = static_cast<pint_t>(this->getReg(UNW_REG_SP));
2981	// According to the s390x ABI, the CFA is at (incoming) SP + 160.
2982	const pint_t cfa = sp + 160;
2983
2984	// Determine current PC and instruction there (this must be either
2985	// a "svc __NR_sigreturn" or "svc __NR_rt_sigreturn").
2986	const pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
2987	const uint16_t inst = _addressSpace.get16(pc);
2988
2989	// Find the addresses of the signo and sigcontext in the frame.
2990	pint_t pSigctx = 0;
2991	pint_t pSigno = 0;
2992
2993	// "svc __NR_sigreturn" uses a non-RT signal trampoline frame.
2994	if (inst == 0x0a77) {
2995	// Layout of a non-RT signal trampoline frame, starting at the CFA:
2996	// - 8-byte signal mask
2997	// - 8-byte pointer to sigcontext, followed by signo
2998	// - 4-byte signo
2999	pSigctx = _addressSpace.get64(cfa + 8);
3000	pSigno = pSigctx + 344;
3001	}
3002
3003	// "svc __NR_rt_sigreturn" uses a RT signal trampoline frame.
3004	if (inst == 0x0aad) {
3005	// Layout of a RT signal trampoline frame, starting at the CFA:
3006	// - 8-byte retcode (+ alignment)
3007	// - 128-byte siginfo struct (starts with signo)
3008	// - ucontext struct:
3009	// - 8-byte long (uc_flags)
3010	// - 8-byte pointer (uc_link)
3011	// - 24-byte stack_t
3012	// - 8 bytes of padding because sigcontext has 16-byte alignment
3013	// - sigcontext/mcontext_t
3014	pSigctx = cfa + 8 + 128 + 8 + 8 + 24 + 8;
3015	pSigno = cfa + 8;
3016	}
3017
3018	assert(pSigctx != 0);
3019	assert(pSigno != 0);
3020
3021	// Offsets from sigcontext to each register.
3022	const pint_t kOffsetPc = 8;
3023	const pint_t kOffsetGprs = 16;
3024	const pint_t kOffsetFprs = 216;
3025
3026	// Restore all registers.
3027	for (int i = 0; i < 16; ++i) {
3028	uint64_t value = _addressSpace.get64(pSigctx + kOffsetGprs +
3029	static_cast<pint_t>(i * 8));
3030	_registers.setRegister(UNW_S390X_R0 + i, value);
3031	}
3032	for (int i = 0; i < 16; ++i) {
3033	static const int fpr[16] = {
3034	UNW_S390X_F0, UNW_S390X_F1, UNW_S390X_F2, UNW_S390X_F3,
3035	UNW_S390X_F4, UNW_S390X_F5, UNW_S390X_F6, UNW_S390X_F7,
3036	UNW_S390X_F8, UNW_S390X_F9, UNW_S390X_F10, UNW_S390X_F11,
3037	UNW_S390X_F12, UNW_S390X_F13, UNW_S390X_F14, UNW_S390X_F15
3038	};
3039	double value = _addressSpace.getDouble(pSigctx + kOffsetFprs +
3040	static_cast<pint_t>(i * 8));
3041	_registers.setFloatRegister(fpr[i], value);
3042	}
3043	_registers.setIP(_addressSpace.get64(pSigctx + kOffsetPc));
3044
3045	// SIGILL, SIGFPE and SIGTRAP are delivered with psw_addr
3046	// after the faulting instruction rather than before it.
3047	// Do not set _isSignalFrame in that case.
3048	uint32_t signo = _addressSpace.get32(pSigno);
3049	_isSignalFrame = (signo != 4 && signo != 5 && signo != 8);
3050
3051	return UNW_STEP_SUCCESS;
3052	}
3053	#endif // defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) &&
3054	// defined(_LIBUNWIND_TARGET_S390X)
3055
3056	#if defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
3057	template <typename A, typename R>
3058	bool UnwindCursor<A, R>::setInfoForSigReturn() {
3059	Dl_info dlinfo;
3060	const auto isSignalHandler = [&](pint_t addr) {
3061	if (!dladdr(reinterpret_cast<void *>(addr), &dlinfo))
3062	return false;
3063	if (strcmp(dlinfo.dli_fname, "commpage"))
3064	return false;
3065	if (dlinfo.dli_sname == NULL ||
3066	strcmp(dlinfo.dli_sname, "commpage_signal_handler"))
3067	return false;
3068	return true;
3069	};
3070
3071	pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
3072	if (!isSignalHandler(pc))
3073	return false;
3074
3075	pint_t start = reinterpret_cast<pint_t>(dlinfo.dli_saddr);
3076
3077	static size_t signalHandlerSize = 0;
3078	if (signalHandlerSize == 0) {
3079	size_t boundLow = 0;
3080	size_t boundHigh = static_cast<size_t>(-1);
3081
3082	area_info areaInfo;
3083	if (get_area_info(area_for(dlinfo.dli_saddr), &areaInfo) == B_OK)
3084	boundHigh = areaInfo.size;
3085
3086	while (boundLow < boundHigh) {
3087	size_t boundMid = boundLow + ((boundHigh - boundLow) / 2);
3088	pint_t test = start + boundMid;
3089	if (test >= start && isSignalHandler(test))
3090	boundLow = boundMid + 1;
3091	else
3092	boundHigh = boundMid;
3093	}
3094
3095	signalHandlerSize = boundHigh;
3096	}
3097
3098	_info = {};
3099	_info.start_ip = start;
3100	_info.end_ip = start + signalHandlerSize;
3101	_isSigReturn = true;
3102
3103	return true;
3104	}
3105
3106	template <typename A, typename R>
3107	int UnwindCursor<A, R>::stepThroughSigReturn() {
3108	_isSignalFrame = true;
3109
3110	#if defined(_LIBUNWIND_TARGET_X86_64)
3111	// Layout of the stack before function call:
3112	// - signal_frame_data
3113	// + siginfo_t (public struct, fairly stable)
3114	// + ucontext_t (public struct, fairly stable)
3115	// - mcontext_t -> Offset 0x70, this is what we want.
3116	// - frame->ip (8 bytes)
3117	// - frame->bp (8 bytes). Not written by the kernel,
3118	// but the signal handler has a "push %rbp" instruction.
3119	pint_t bp = this->getReg(UNW_X86_64_RBP);
3120	vregs *regs = (vregs *)(bp + 0x70);
3121
3122	_registers.setRegister(UNW_REG_IP, regs->rip);
3123	_registers.setRegister(UNW_REG_SP, regs->rsp);
3124	_registers.setRegister(UNW_X86_64_RAX, regs->rax);
3125	_registers.setRegister(UNW_X86_64_RDX, regs->rdx);
3126	_registers.setRegister(UNW_X86_64_RCX, regs->rcx);
3127	_registers.setRegister(UNW_X86_64_RBX, regs->rbx);
3128	_registers.setRegister(UNW_X86_64_RSI, regs->rsi);
3129	_registers.setRegister(UNW_X86_64_RDI, regs->rdi);
3130	_registers.setRegister(UNW_X86_64_RBP, regs->rbp);
3131	_registers.setRegister(UNW_X86_64_R8, regs->r8);
3132	_registers.setRegister(UNW_X86_64_R9, regs->r9);
3133	_registers.setRegister(UNW_X86_64_R10, regs->r10);
3134	_registers.setRegister(UNW_X86_64_R11, regs->r11);
3135	_registers.setRegister(UNW_X86_64_R12, regs->r12);
3136	_registers.setRegister(UNW_X86_64_R13, regs->r13);
3137	_registers.setRegister(UNW_X86_64_R14, regs->r14);
3138	_registers.setRegister(UNW_X86_64_R15, regs->r15);
3139	// TODO: XMM
3140	#endif // defined(_LIBUNWIND_TARGET_X86_64)
3141
3142	return UNW_STEP_SUCCESS;
3143	}
3144	#endif // defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
3145
3146	template <typename A, typename R> int UnwindCursor<A, R>::step(bool stage2) {
3147	(void)stage2;
3148	// Bottom of stack is defined is when unwind info cannot be found.
3149	if (_unwindInfoMissing)
3150	return UNW_STEP_END;
3151
3152	// Use unwinding info to modify register set as if function returned.
3153	int result;
3154	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) || \
3155	defined(_LIBUNWIND_CHECK_HAIKU_SIGRETURN)
3156	if (_isSigReturn) {
3157	result = this->stepThroughSigReturn();
3158	} else
3159	#endif
3160	{
3161	#if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
3162	result = this->stepWithCompactEncoding(stage2);
3163	#elif defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
3164	result = this->stepWithSEHData();
3165	#elif defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
3166	result = this->stepWithTBTableData();
3167	#elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
3168	result = this->stepWithDwarfFDE(stage2);
3169	#elif defined(_LIBUNWIND_ARM_EHABI)
3170	result = this->stepWithEHABI();
3171	#else
3172	#error Need _LIBUNWIND_SUPPORT_COMPACT_UNWIND or \
3173	_LIBUNWIND_SUPPORT_SEH_UNWIND or \
3174	_LIBUNWIND_SUPPORT_DWARF_UNWIND or \
3175	_LIBUNWIND_ARM_EHABI
3176	#endif
3177	}
3178
3179	// update info based on new PC
3180	if (result == UNW_STEP_SUCCESS) {
3181	this->setInfoBasedOnIPRegister(true);
3182	if (_unwindInfoMissing)
3183	return UNW_STEP_END;
3184	}
3185
3186	return result;
3187	}
3188
3189	template <typename A, typename R>
3190	void UnwindCursor<A, R>::getInfo(unw_proc_info_t *info) {
3191	if (_unwindInfoMissing)
3192	memset(s: info, c: 0, n: sizeof(*info));
3193	else
3194	*info = _info;
3195	}
3196
3197	template <typename A, typename R>
3198	bool UnwindCursor<A, R>::getFunctionName(char *buf, size_t bufLen,
3199	unw_word_t *offset) {
3200	return _addressSpace.findFunctionName((pint_t)this->getReg(regNum: UNW_REG_IP),
3201	buf, bufLen, offset);
3202	}
3203
3204	#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
3205	template <typename A, typename R>
3206	bool UnwindCursor<A, R>::isReadableAddr(const pint_t addr) const {
3207	// We use SYS_rt_sigprocmask, inspired by Abseil's AddressIsReadable.
3208
3209	const auto sigsetAddr = reinterpret_cast<sigset_t *>(addr);
3210	// We have to check that addr is nullptr because sigprocmask allows that
3211	// as an argument without failure.
3212	if (!sigsetAddr)
3213	return false;
3214	const auto saveErrno = errno;
3215	// We MUST use a raw syscall here, as wrappers may try to access
3216	// sigsetAddr which may cause a SIGSEGV. A raw syscall however is
3217	// safe. Additionally, we need to pass the kernel_sigset_size, which is
3218	// different from libc sizeof(sigset_t). For the majority of architectures,
3219	// it's 64 bits (_NSIG), and libc NSIG is _NSIG + 1.
3220	const auto kernelSigsetSize = NSIG / 8;
3221	[[maybe_unused]] const int Result = syscall(
3222	SYS_rt_sigprocmask, /*how=*/~0, sigsetAddr, nullptr, kernelSigsetSize);
3223	// Because our "how" is invalid, this syscall should always fail, and our
3224	// errno should always be EINVAL or an EFAULT. This relies on the Linux
3225	// kernel to check copy_from_user before checking if the "how" argument is
3226	// invalid.
3227	assert(Result == -1);
3228	assert(errno == EFAULT || errno == EINVAL);
3229	const auto readable = errno != EFAULT;
3230	errno = saveErrno;
3231	return readable;
3232	}
3233	#endif
3234
3235	#if defined(_LIBUNWIND_USE_CET) || defined(_LIBUNWIND_USE_GCS)
3236	extern "C" void *__libunwind_shstk_get_registers(unw_cursor_t *cursor) {
3237	AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
3238	return co->get_registers();
3239	}
3240	#endif
3241	} // namespace libunwind
3242
3243	#endif // __UNWINDCURSOR_HPP__
3244