1 //===------------------------- UnwindCursor.hpp ---------------------------===//
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 "cet_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 
28 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
29 // Provide a definition for the DISPATCHER_CONTEXT struct for old (Win7 and
30 // earlier) SDKs.
31 // MinGW-w64 has always provided this struct.
32   #if defined(_WIN32) && defined(_LIBUNWIND_TARGET_X86_64) && \
33       !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
34 struct _DISPATCHER_CONTEXT {
35   ULONG64 ControlPc;
36   ULONG64 ImageBase;
37   PRUNTIME_FUNCTION FunctionEntry;
38   ULONG64 EstablisherFrame;
39   ULONG64 TargetIp;
40   PCONTEXT ContextRecord;
41   PEXCEPTION_ROUTINE LanguageHandler;
42   PVOID HandlerData;
43   PUNWIND_HISTORY_TABLE HistoryTable;
44   ULONG ScopeIndex;
45   ULONG Fill0;
46 };
47   #endif
48 
49 struct UNWIND_INFO {
50   uint8_t Version : 3;
51   uint8_t Flags : 5;
52   uint8_t SizeOfProlog;
53   uint8_t CountOfCodes;
54   uint8_t FrameRegister : 4;
55   uint8_t FrameOffset : 4;
56   uint16_t UnwindCodes[2];
57 };
58 
59 extern "C" _Unwind_Reason_Code __libunwind_seh_personality(
60     int, _Unwind_Action, uint64_t, _Unwind_Exception *,
61     struct _Unwind_Context *);
62 
63 #endif
64 
65 #include "config.h"
66 
67 #include "AddressSpace.hpp"
68 #include "CompactUnwinder.hpp"
69 #include "config.h"
70 #include "DwarfInstructions.hpp"
71 #include "EHHeaderParser.hpp"
72 #include "libunwind.h"
73 #include "Registers.hpp"
74 #include "RWMutex.hpp"
75 #include "Unwind-EHABI.h"
76 
77 namespace libunwind {
78 
79 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
80 /// Cache of recently found FDEs.
81 template <typename A>
82 class _LIBUNWIND_HIDDEN DwarfFDECache {
83   typedef typename A::pint_t pint_t;
84 public:
85   static constexpr pint_t kSearchAll = static_cast<pint_t>(-1);
86   static pint_t findFDE(pint_t mh, pint_t pc);
87   static void add(pint_t mh, pint_t ip_start, pint_t ip_end, pint_t fde);
88   static void removeAllIn(pint_t mh);
89   static void iterateCacheEntries(void (*func)(unw_word_t ip_start,
90                                                unw_word_t ip_end,
91                                                unw_word_t fde, unw_word_t mh));
92 
93 private:
94 
95   struct entry {
96     pint_t mh;
97     pint_t ip_start;
98     pint_t ip_end;
99     pint_t fde;
100   };
101 
102   // These fields are all static to avoid needing an initializer.
103   // There is only one instance of this class per process.
104   static RWMutex _lock;
105 #ifdef __APPLE__
106   static void dyldUnloadHook(const struct mach_header *mh, intptr_t slide);
107   static bool _registeredForDyldUnloads;
108 #endif
109   static entry *_buffer;
110   static entry *_bufferUsed;
111   static entry *_bufferEnd;
112   static entry _initialBuffer[64];
113 };
114 
115 template <typename A>
116 typename DwarfFDECache<A>::entry *
117 DwarfFDECache<A>::_buffer = _initialBuffer;
118 
119 template <typename A>
120 typename DwarfFDECache<A>::entry *
121 DwarfFDECache<A>::_bufferUsed = _initialBuffer;
122 
123 template <typename A>
124 typename DwarfFDECache<A>::entry *
125 DwarfFDECache<A>::_bufferEnd = &_initialBuffer[64];
126 
127 template <typename A>
128 typename DwarfFDECache<A>::entry DwarfFDECache<A>::_initialBuffer[64];
129 
130 template <typename A>
131 RWMutex DwarfFDECache<A>::_lock;
132 
133 #ifdef __APPLE__
134 template <typename A>
135 bool DwarfFDECache<A>::_registeredForDyldUnloads = false;
136 #endif
137 
138 template <typename A>
findFDE(pint_t mh,pint_t pc)139 typename A::pint_t DwarfFDECache<A>::findFDE(pint_t mh, pint_t pc) {
140   pint_t result = 0;
141   _LIBUNWIND_LOG_IF_FALSE(_lock.lock_shared());
142   for (entry *p = _buffer; p < _bufferUsed; ++p) {
143     if ((mh == p->mh) || (mh == kSearchAll)) {
144       if ((p->ip_start <= pc) && (pc < p->ip_end)) {
145         result = p->fde;
146         break;
147       }
148     }
149   }
150   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock_shared());
151   return result;
152 }
153 
154 template <typename A>
add(pint_t mh,pint_t ip_start,pint_t ip_end,pint_t fde)155 void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
156                            pint_t fde) {
157 #if !defined(_LIBUNWIND_NO_HEAP)
158   _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
159   if (_bufferUsed >= _bufferEnd) {
160     size_t oldSize = (size_t)(_bufferEnd - _buffer);
161     size_t newSize = oldSize * 4;
162     // Can't use operator new (we are below it).
163     entry *newBuffer = (entry *)malloc(newSize * sizeof(entry));
164     memcpy(newBuffer, _buffer, oldSize * sizeof(entry));
165     if (_buffer != _initialBuffer)
166       free(_buffer);
167     _buffer = newBuffer;
168     _bufferUsed = &newBuffer[oldSize];
169     _bufferEnd = &newBuffer[newSize];
170   }
171   _bufferUsed->mh = mh;
172   _bufferUsed->ip_start = ip_start;
173   _bufferUsed->ip_end = ip_end;
174   _bufferUsed->fde = fde;
175   ++_bufferUsed;
176 #ifdef __APPLE__
177   if (!_registeredForDyldUnloads) {
178     _dyld_register_func_for_remove_image(&dyldUnloadHook);
179     _registeredForDyldUnloads = true;
180   }
181 #endif
182   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
183 #endif
184 }
185 
186 template <typename A>
removeAllIn(pint_t mh)187 void DwarfFDECache<A>::removeAllIn(pint_t mh) {
188   _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
189   entry *d = _buffer;
190   for (const entry *s = _buffer; s < _bufferUsed; ++s) {
191     if (s->mh != mh) {
192       if (d != s)
193         *d = *s;
194       ++d;
195     }
196   }
197   _bufferUsed = d;
198   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
199 }
200 
201 #ifdef __APPLE__
202 template <typename A>
dyldUnloadHook(const struct mach_header * mh,intptr_t)203 void DwarfFDECache<A>::dyldUnloadHook(const struct mach_header *mh, intptr_t ) {
204   removeAllIn((pint_t) mh);
205 }
206 #endif
207 
208 template <typename A>
iterateCacheEntries(void (* func)(unw_word_t ip_start,unw_word_t ip_end,unw_word_t fde,unw_word_t mh))209 void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
210     unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
211   _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
212   for (entry *p = _buffer; p < _bufferUsed; ++p) {
213     (*func)(p->ip_start, p->ip_end, p->fde, p->mh);
214   }
215   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
216 }
217 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
218 
219 
220 #define arrayoffsetof(type, index, field) ((size_t)(&((type *)0)[index].field))
221 
222 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
223 template <typename A> class UnwindSectionHeader {
224 public:
UnwindSectionHeader(A & addressSpace,typename A::pint_t addr)225   UnwindSectionHeader(A &addressSpace, typename A::pint_t addr)
226       : _addressSpace(addressSpace), _addr(addr) {}
227 
version() const228   uint32_t version() const {
229     return _addressSpace.get32(_addr +
230                                offsetof(unwind_info_section_header, version));
231   }
commonEncodingsArraySectionOffset() const232   uint32_t commonEncodingsArraySectionOffset() const {
233     return _addressSpace.get32(_addr +
234                                offsetof(unwind_info_section_header,
235                                         commonEncodingsArraySectionOffset));
236   }
commonEncodingsArrayCount() const237   uint32_t commonEncodingsArrayCount() const {
238     return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
239                                                 commonEncodingsArrayCount));
240   }
personalityArraySectionOffset() const241   uint32_t personalityArraySectionOffset() const {
242     return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
243                                                 personalityArraySectionOffset));
244   }
personalityArrayCount() const245   uint32_t personalityArrayCount() const {
246     return _addressSpace.get32(
247         _addr + offsetof(unwind_info_section_header, personalityArrayCount));
248   }
indexSectionOffset() const249   uint32_t indexSectionOffset() const {
250     return _addressSpace.get32(
251         _addr + offsetof(unwind_info_section_header, indexSectionOffset));
252   }
indexCount() const253   uint32_t indexCount() const {
254     return _addressSpace.get32(
255         _addr + offsetof(unwind_info_section_header, indexCount));
256   }
257 
258 private:
259   A                     &_addressSpace;
260   typename A::pint_t     _addr;
261 };
262 
263 template <typename A> class UnwindSectionIndexArray {
264 public:
UnwindSectionIndexArray(A & addressSpace,typename A::pint_t addr)265   UnwindSectionIndexArray(A &addressSpace, typename A::pint_t addr)
266       : _addressSpace(addressSpace), _addr(addr) {}
267 
functionOffset(uint32_t index) const268   uint32_t functionOffset(uint32_t index) const {
269     return _addressSpace.get32(
270         _addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
271                               functionOffset));
272   }
secondLevelPagesSectionOffset(uint32_t index) const273   uint32_t secondLevelPagesSectionOffset(uint32_t index) const {
274     return _addressSpace.get32(
275         _addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
276                               secondLevelPagesSectionOffset));
277   }
lsdaIndexArraySectionOffset(uint32_t index) const278   uint32_t lsdaIndexArraySectionOffset(uint32_t index) const {
279     return _addressSpace.get32(
280         _addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
281                               lsdaIndexArraySectionOffset));
282   }
283 
284 private:
285   A                   &_addressSpace;
286   typename A::pint_t   _addr;
287 };
288 
289 template <typename A> class UnwindSectionRegularPageHeader {
290 public:
UnwindSectionRegularPageHeader(A & addressSpace,typename A::pint_t addr)291   UnwindSectionRegularPageHeader(A &addressSpace, typename A::pint_t addr)
292       : _addressSpace(addressSpace), _addr(addr) {}
293 
kind() const294   uint32_t kind() const {
295     return _addressSpace.get32(
296         _addr + offsetof(unwind_info_regular_second_level_page_header, kind));
297   }
entryPageOffset() const298   uint16_t entryPageOffset() const {
299     return _addressSpace.get16(
300         _addr + offsetof(unwind_info_regular_second_level_page_header,
301                          entryPageOffset));
302   }
entryCount() const303   uint16_t entryCount() const {
304     return _addressSpace.get16(
305         _addr +
306         offsetof(unwind_info_regular_second_level_page_header, entryCount));
307   }
308 
309 private:
310   A &_addressSpace;
311   typename A::pint_t _addr;
312 };
313 
314 template <typename A> class UnwindSectionRegularArray {
315 public:
UnwindSectionRegularArray(A & addressSpace,typename A::pint_t addr)316   UnwindSectionRegularArray(A &addressSpace, typename A::pint_t addr)
317       : _addressSpace(addressSpace), _addr(addr) {}
318 
functionOffset(uint32_t index) const319   uint32_t functionOffset(uint32_t index) const {
320     return _addressSpace.get32(
321         _addr + arrayoffsetof(unwind_info_regular_second_level_entry, index,
322                               functionOffset));
323   }
encoding(uint32_t index) const324   uint32_t encoding(uint32_t index) const {
325     return _addressSpace.get32(
326         _addr +
327         arrayoffsetof(unwind_info_regular_second_level_entry, index, encoding));
328   }
329 
330 private:
331   A &_addressSpace;
332   typename A::pint_t _addr;
333 };
334 
335 template <typename A> class UnwindSectionCompressedPageHeader {
336 public:
UnwindSectionCompressedPageHeader(A & addressSpace,typename A::pint_t addr)337   UnwindSectionCompressedPageHeader(A &addressSpace, typename A::pint_t addr)
338       : _addressSpace(addressSpace), _addr(addr) {}
339 
kind() const340   uint32_t kind() const {
341     return _addressSpace.get32(
342         _addr +
343         offsetof(unwind_info_compressed_second_level_page_header, kind));
344   }
entryPageOffset() const345   uint16_t entryPageOffset() const {
346     return _addressSpace.get16(
347         _addr + offsetof(unwind_info_compressed_second_level_page_header,
348                          entryPageOffset));
349   }
entryCount() const350   uint16_t entryCount() const {
351     return _addressSpace.get16(
352         _addr +
353         offsetof(unwind_info_compressed_second_level_page_header, entryCount));
354   }
encodingsPageOffset() const355   uint16_t encodingsPageOffset() const {
356     return _addressSpace.get16(
357         _addr + offsetof(unwind_info_compressed_second_level_page_header,
358                          encodingsPageOffset));
359   }
encodingsCount() const360   uint16_t encodingsCount() const {
361     return _addressSpace.get16(
362         _addr + offsetof(unwind_info_compressed_second_level_page_header,
363                          encodingsCount));
364   }
365 
366 private:
367   A &_addressSpace;
368   typename A::pint_t _addr;
369 };
370 
371 template <typename A> class UnwindSectionCompressedArray {
372 public:
UnwindSectionCompressedArray(A & addressSpace,typename A::pint_t addr)373   UnwindSectionCompressedArray(A &addressSpace, typename A::pint_t addr)
374       : _addressSpace(addressSpace), _addr(addr) {}
375 
functionOffset(uint32_t index) const376   uint32_t functionOffset(uint32_t index) const {
377     return UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(
378         _addressSpace.get32(_addr + index * sizeof(uint32_t)));
379   }
encodingIndex(uint32_t index) const380   uint16_t encodingIndex(uint32_t index) const {
381     return UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(
382         _addressSpace.get32(_addr + index * sizeof(uint32_t)));
383   }
384 
385 private:
386   A &_addressSpace;
387   typename A::pint_t _addr;
388 };
389 
390 template <typename A> class UnwindSectionLsdaArray {
391 public:
UnwindSectionLsdaArray(A & addressSpace,typename A::pint_t addr)392   UnwindSectionLsdaArray(A &addressSpace, typename A::pint_t addr)
393       : _addressSpace(addressSpace), _addr(addr) {}
394 
functionOffset(uint32_t index) const395   uint32_t functionOffset(uint32_t index) const {
396     return _addressSpace.get32(
397         _addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
398                               index, functionOffset));
399   }
lsdaOffset(uint32_t index) const400   uint32_t lsdaOffset(uint32_t index) const {
401     return _addressSpace.get32(
402         _addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
403                               index, lsdaOffset));
404   }
405 
406 private:
407   A                   &_addressSpace;
408   typename A::pint_t   _addr;
409 };
410 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
411 
412 class _LIBUNWIND_HIDDEN AbstractUnwindCursor {
413 public:
414   // NOTE: provide a class specific placement deallocation function (S5.3.4 p20)
415   // This avoids an unnecessary dependency to libc++abi.
operator delete(void *,size_t)416   void operator delete(void *, size_t) {}
417 
~AbstractUnwindCursor()418   virtual ~AbstractUnwindCursor() {}
validReg(int)419   virtual bool validReg(int) { _LIBUNWIND_ABORT("validReg not implemented"); }
getReg(int)420   virtual unw_word_t getReg(int) { _LIBUNWIND_ABORT("getReg not implemented"); }
setReg(int,unw_word_t)421   virtual void setReg(int, unw_word_t) {
422     _LIBUNWIND_ABORT("setReg not implemented");
423   }
validFloatReg(int)424   virtual bool validFloatReg(int) {
425     _LIBUNWIND_ABORT("validFloatReg not implemented");
426   }
getFloatReg(int)427   virtual unw_fpreg_t getFloatReg(int) {
428     _LIBUNWIND_ABORT("getFloatReg not implemented");
429   }
setFloatReg(int,unw_fpreg_t)430   virtual void setFloatReg(int, unw_fpreg_t) {
431     _LIBUNWIND_ABORT("setFloatReg not implemented");
432   }
step()433   virtual int step() { _LIBUNWIND_ABORT("step not implemented"); }
getInfo(unw_proc_info_t *)434   virtual void getInfo(unw_proc_info_t *) {
435     _LIBUNWIND_ABORT("getInfo not implemented");
436   }
jumpto()437   virtual void jumpto() { _LIBUNWIND_ABORT("jumpto not implemented"); }
isSignalFrame()438   virtual bool isSignalFrame() {
439     _LIBUNWIND_ABORT("isSignalFrame not implemented");
440   }
getFunctionName(char *,size_t,unw_word_t *)441   virtual bool getFunctionName(char *, size_t, unw_word_t *) {
442     _LIBUNWIND_ABORT("getFunctionName not implemented");
443   }
setInfoBasedOnIPRegister(bool=false)444   virtual void setInfoBasedOnIPRegister(bool = false) {
445     _LIBUNWIND_ABORT("setInfoBasedOnIPRegister not implemented");
446   }
getRegisterName(int)447   virtual const char *getRegisterName(int) {
448     _LIBUNWIND_ABORT("getRegisterName not implemented");
449   }
450 #ifdef __arm__
saveVFPAsX()451   virtual void saveVFPAsX() { _LIBUNWIND_ABORT("saveVFPAsX not implemented"); }
452 #endif
453 
454 #if defined(_LIBUNWIND_USE_CET)
get_registers()455   virtual void *get_registers() {
456     _LIBUNWIND_ABORT("get_registers not implemented");
457   }
458 #endif
459 };
460 
461 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)
462 
463 /// \c UnwindCursor contains all state (including all register values) during
464 /// an unwind.  This is normally stack-allocated inside a unw_cursor_t.
465 template <typename A, typename R>
466 class UnwindCursor : public AbstractUnwindCursor {
467   typedef typename A::pint_t pint_t;
468 public:
469                       UnwindCursor(unw_context_t *context, A &as);
470                       UnwindCursor(CONTEXT *context, A &as);
471                       UnwindCursor(A &as, void *threadArg);
~UnwindCursor()472   virtual             ~UnwindCursor() {}
473   virtual bool        validReg(int);
474   virtual unw_word_t  getReg(int);
475   virtual void        setReg(int, unw_word_t);
476   virtual bool        validFloatReg(int);
477   virtual unw_fpreg_t getFloatReg(int);
478   virtual void        setFloatReg(int, unw_fpreg_t);
479   virtual int         step();
480   virtual void        getInfo(unw_proc_info_t *);
481   virtual void        jumpto();
482   virtual bool        isSignalFrame();
483   virtual bool        getFunctionName(char *buf, size_t len, unw_word_t *off);
484   virtual void        setInfoBasedOnIPRegister(bool isReturnAddress = false);
485   virtual const char *getRegisterName(int num);
486 #ifdef __arm__
487   virtual void        saveVFPAsX();
488 #endif
489 
getDispatcherContext()490   DISPATCHER_CONTEXT *getDispatcherContext() { return &_dispContext; }
setDispatcherContext(DISPATCHER_CONTEXT * disp)491   void setDispatcherContext(DISPATCHER_CONTEXT *disp) { _dispContext = *disp; }
492 
493   // libunwind does not and should not depend on C++ library which means that we
494   // need our own defition of inline placement new.
operator new(size_t,UnwindCursor<A,R> * p)495   static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
496 
497 private:
498 
getLastPC() const499   pint_t getLastPC() const { return _dispContext.ControlPc; }
setLastPC(pint_t pc)500   void setLastPC(pint_t pc) { _dispContext.ControlPc = pc; }
lookUpSEHUnwindInfo(pint_t pc,pint_t * base)501   RUNTIME_FUNCTION *lookUpSEHUnwindInfo(pint_t pc, pint_t *base) {
502     _dispContext.FunctionEntry = RtlLookupFunctionEntry(pc,
503                                                         &_dispContext.ImageBase,
504                                                         _dispContext.HistoryTable);
505     *base = _dispContext.ImageBase;
506     return _dispContext.FunctionEntry;
507   }
508   bool getInfoFromSEH(pint_t pc);
stepWithSEHData()509   int stepWithSEHData() {
510     _dispContext.LanguageHandler = RtlVirtualUnwind(UNW_FLAG_UHANDLER,
511                                                     _dispContext.ImageBase,
512                                                     _dispContext.ControlPc,
513                                                     _dispContext.FunctionEntry,
514                                                     _dispContext.ContextRecord,
515                                                     &_dispContext.HandlerData,
516                                                     &_dispContext.EstablisherFrame,
517                                                     NULL);
518     // Update some fields of the unwind info now, since we have them.
519     _info.lsda = reinterpret_cast<unw_word_t>(_dispContext.HandlerData);
520     if (_dispContext.LanguageHandler) {
521       _info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
522     } else
523       _info.handler = 0;
524     return UNW_STEP_SUCCESS;
525   }
526 
527   A                   &_addressSpace;
528   unw_proc_info_t      _info;
529   DISPATCHER_CONTEXT   _dispContext;
530   CONTEXT              _msContext;
531   UNWIND_HISTORY_TABLE _histTable;
532   bool                 _unwindInfoMissing;
533 };
534 
535 
536 template <typename A, typename R>
UnwindCursor(unw_context_t * context,A & as)537 UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
538     : _addressSpace(as), _unwindInfoMissing(false) {
539   static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
540                 "UnwindCursor<> does not fit in unw_cursor_t");
541   static_assert((alignof(UnwindCursor<A, R>) <= alignof(unw_cursor_t)),
542                 "UnwindCursor<> requires more alignment than unw_cursor_t");
543   memset(&_info, 0, sizeof(_info));
544   memset(&_histTable, 0, sizeof(_histTable));
545   _dispContext.ContextRecord = &_msContext;
546   _dispContext.HistoryTable = &_histTable;
547   // Initialize MS context from ours.
548   R r(context);
549   _msContext.ContextFlags = CONTEXT_CONTROL|CONTEXT_INTEGER|CONTEXT_FLOATING_POINT;
550 #if defined(_LIBUNWIND_TARGET_X86_64)
551   _msContext.Rax = r.getRegister(UNW_X86_64_RAX);
552   _msContext.Rcx = r.getRegister(UNW_X86_64_RCX);
553   _msContext.Rdx = r.getRegister(UNW_X86_64_RDX);
554   _msContext.Rbx = r.getRegister(UNW_X86_64_RBX);
555   _msContext.Rsp = r.getRegister(UNW_X86_64_RSP);
556   _msContext.Rbp = r.getRegister(UNW_X86_64_RBP);
557   _msContext.Rsi = r.getRegister(UNW_X86_64_RSI);
558   _msContext.Rdi = r.getRegister(UNW_X86_64_RDI);
559   _msContext.R8 = r.getRegister(UNW_X86_64_R8);
560   _msContext.R9 = r.getRegister(UNW_X86_64_R9);
561   _msContext.R10 = r.getRegister(UNW_X86_64_R10);
562   _msContext.R11 = r.getRegister(UNW_X86_64_R11);
563   _msContext.R12 = r.getRegister(UNW_X86_64_R12);
564   _msContext.R13 = r.getRegister(UNW_X86_64_R13);
565   _msContext.R14 = r.getRegister(UNW_X86_64_R14);
566   _msContext.R15 = r.getRegister(UNW_X86_64_R15);
567   _msContext.Rip = r.getRegister(UNW_REG_IP);
568   union {
569     v128 v;
570     M128A m;
571   } t;
572   t.v = r.getVectorRegister(UNW_X86_64_XMM0);
573   _msContext.Xmm0 = t.m;
574   t.v = r.getVectorRegister(UNW_X86_64_XMM1);
575   _msContext.Xmm1 = t.m;
576   t.v = r.getVectorRegister(UNW_X86_64_XMM2);
577   _msContext.Xmm2 = t.m;
578   t.v = r.getVectorRegister(UNW_X86_64_XMM3);
579   _msContext.Xmm3 = t.m;
580   t.v = r.getVectorRegister(UNW_X86_64_XMM4);
581   _msContext.Xmm4 = t.m;
582   t.v = r.getVectorRegister(UNW_X86_64_XMM5);
583   _msContext.Xmm5 = t.m;
584   t.v = r.getVectorRegister(UNW_X86_64_XMM6);
585   _msContext.Xmm6 = t.m;
586   t.v = r.getVectorRegister(UNW_X86_64_XMM7);
587   _msContext.Xmm7 = t.m;
588   t.v = r.getVectorRegister(UNW_X86_64_XMM8);
589   _msContext.Xmm8 = t.m;
590   t.v = r.getVectorRegister(UNW_X86_64_XMM9);
591   _msContext.Xmm9 = t.m;
592   t.v = r.getVectorRegister(UNW_X86_64_XMM10);
593   _msContext.Xmm10 = t.m;
594   t.v = r.getVectorRegister(UNW_X86_64_XMM11);
595   _msContext.Xmm11 = t.m;
596   t.v = r.getVectorRegister(UNW_X86_64_XMM12);
597   _msContext.Xmm12 = t.m;
598   t.v = r.getVectorRegister(UNW_X86_64_XMM13);
599   _msContext.Xmm13 = t.m;
600   t.v = r.getVectorRegister(UNW_X86_64_XMM14);
601   _msContext.Xmm14 = t.m;
602   t.v = r.getVectorRegister(UNW_X86_64_XMM15);
603   _msContext.Xmm15 = t.m;
604 #elif defined(_LIBUNWIND_TARGET_ARM)
605   _msContext.R0 = r.getRegister(UNW_ARM_R0);
606   _msContext.R1 = r.getRegister(UNW_ARM_R1);
607   _msContext.R2 = r.getRegister(UNW_ARM_R2);
608   _msContext.R3 = r.getRegister(UNW_ARM_R3);
609   _msContext.R4 = r.getRegister(UNW_ARM_R4);
610   _msContext.R5 = r.getRegister(UNW_ARM_R5);
611   _msContext.R6 = r.getRegister(UNW_ARM_R6);
612   _msContext.R7 = r.getRegister(UNW_ARM_R7);
613   _msContext.R8 = r.getRegister(UNW_ARM_R8);
614   _msContext.R9 = r.getRegister(UNW_ARM_R9);
615   _msContext.R10 = r.getRegister(UNW_ARM_R10);
616   _msContext.R11 = r.getRegister(UNW_ARM_R11);
617   _msContext.R12 = r.getRegister(UNW_ARM_R12);
618   _msContext.Sp = r.getRegister(UNW_ARM_SP);
619   _msContext.Lr = r.getRegister(UNW_ARM_LR);
620   _msContext.Pc = r.getRegister(UNW_ARM_IP);
621   for (int i = UNW_ARM_D0; i <= UNW_ARM_D31; ++i) {
622     union {
623       uint64_t w;
624       double d;
625     } d;
626     d.d = r.getFloatRegister(i);
627     _msContext.D[i - UNW_ARM_D0] = d.w;
628   }
629 #elif defined(_LIBUNWIND_TARGET_AARCH64)
630   for (int i = UNW_AARCH64_X0; i <= UNW_ARM64_X30; ++i)
631     _msContext.X[i - UNW_AARCH64_X0] = r.getRegister(i);
632   _msContext.Sp = r.getRegister(UNW_REG_SP);
633   _msContext.Pc = r.getRegister(UNW_REG_IP);
634   for (int i = UNW_AARCH64_V0; i <= UNW_ARM64_D31; ++i)
635     _msContext.V[i - UNW_AARCH64_V0].D[0] = r.getFloatRegister(i);
636 #endif
637 }
638 
639 template <typename A, typename R>
UnwindCursor(CONTEXT * context,A & as)640 UnwindCursor<A, R>::UnwindCursor(CONTEXT *context, A &as)
641     : _addressSpace(as), _unwindInfoMissing(false) {
642   static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
643                 "UnwindCursor<> does not fit in unw_cursor_t");
644   memset(&_info, 0, sizeof(_info));
645   memset(&_histTable, 0, sizeof(_histTable));
646   _dispContext.ContextRecord = &_msContext;
647   _dispContext.HistoryTable = &_histTable;
648   _msContext = *context;
649 }
650 
651 
652 template <typename A, typename R>
validReg(int regNum)653 bool UnwindCursor<A, R>::validReg(int regNum) {
654   if (regNum == UNW_REG_IP || regNum == UNW_REG_SP) return true;
655 #if defined(_LIBUNWIND_TARGET_X86_64)
656   if (regNum >= UNW_X86_64_RAX && regNum <= UNW_X86_64_R15) return true;
657 #elif defined(_LIBUNWIND_TARGET_ARM)
658   if (regNum >= UNW_ARM_R0 && regNum <= UNW_ARM_R15) return true;
659 #elif defined(_LIBUNWIND_TARGET_AARCH64)
660   if (regNum >= UNW_AARCH64_X0 && regNum <= UNW_ARM64_X30) return true;
661 #endif
662   return false;
663 }
664 
665 template <typename A, typename R>
getReg(int regNum)666 unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
667   switch (regNum) {
668 #if defined(_LIBUNWIND_TARGET_X86_64)
669   case UNW_REG_IP: return _msContext.Rip;
670   case UNW_X86_64_RAX: return _msContext.Rax;
671   case UNW_X86_64_RDX: return _msContext.Rdx;
672   case UNW_X86_64_RCX: return _msContext.Rcx;
673   case UNW_X86_64_RBX: return _msContext.Rbx;
674   case UNW_REG_SP:
675   case UNW_X86_64_RSP: return _msContext.Rsp;
676   case UNW_X86_64_RBP: return _msContext.Rbp;
677   case UNW_X86_64_RSI: return _msContext.Rsi;
678   case UNW_X86_64_RDI: return _msContext.Rdi;
679   case UNW_X86_64_R8: return _msContext.R8;
680   case UNW_X86_64_R9: return _msContext.R9;
681   case UNW_X86_64_R10: return _msContext.R10;
682   case UNW_X86_64_R11: return _msContext.R11;
683   case UNW_X86_64_R12: return _msContext.R12;
684   case UNW_X86_64_R13: return _msContext.R13;
685   case UNW_X86_64_R14: return _msContext.R14;
686   case UNW_X86_64_R15: return _msContext.R15;
687 #elif defined(_LIBUNWIND_TARGET_ARM)
688   case UNW_ARM_R0: return _msContext.R0;
689   case UNW_ARM_R1: return _msContext.R1;
690   case UNW_ARM_R2: return _msContext.R2;
691   case UNW_ARM_R3: return _msContext.R3;
692   case UNW_ARM_R4: return _msContext.R4;
693   case UNW_ARM_R5: return _msContext.R5;
694   case UNW_ARM_R6: return _msContext.R6;
695   case UNW_ARM_R7: return _msContext.R7;
696   case UNW_ARM_R8: return _msContext.R8;
697   case UNW_ARM_R9: return _msContext.R9;
698   case UNW_ARM_R10: return _msContext.R10;
699   case UNW_ARM_R11: return _msContext.R11;
700   case UNW_ARM_R12: return _msContext.R12;
701   case UNW_REG_SP:
702   case UNW_ARM_SP: return _msContext.Sp;
703   case UNW_ARM_LR: return _msContext.Lr;
704   case UNW_REG_IP:
705   case UNW_ARM_IP: return _msContext.Pc;
706 #elif defined(_LIBUNWIND_TARGET_AARCH64)
707   case UNW_REG_SP: return _msContext.Sp;
708   case UNW_REG_IP: return _msContext.Pc;
709   default: return _msContext.X[regNum - UNW_AARCH64_X0];
710 #endif
711   }
712   _LIBUNWIND_ABORT("unsupported register");
713 }
714 
715 template <typename A, typename R>
setReg(int regNum,unw_word_t value)716 void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
717   switch (regNum) {
718 #if defined(_LIBUNWIND_TARGET_X86_64)
719   case UNW_REG_IP: _msContext.Rip = value; break;
720   case UNW_X86_64_RAX: _msContext.Rax = value; break;
721   case UNW_X86_64_RDX: _msContext.Rdx = value; break;
722   case UNW_X86_64_RCX: _msContext.Rcx = value; break;
723   case UNW_X86_64_RBX: _msContext.Rbx = value; break;
724   case UNW_REG_SP:
725   case UNW_X86_64_RSP: _msContext.Rsp = value; break;
726   case UNW_X86_64_RBP: _msContext.Rbp = value; break;
727   case UNW_X86_64_RSI: _msContext.Rsi = value; break;
728   case UNW_X86_64_RDI: _msContext.Rdi = value; break;
729   case UNW_X86_64_R8: _msContext.R8 = value; break;
730   case UNW_X86_64_R9: _msContext.R9 = value; break;
731   case UNW_X86_64_R10: _msContext.R10 = value; break;
732   case UNW_X86_64_R11: _msContext.R11 = value; break;
733   case UNW_X86_64_R12: _msContext.R12 = value; break;
734   case UNW_X86_64_R13: _msContext.R13 = value; break;
735   case UNW_X86_64_R14: _msContext.R14 = value; break;
736   case UNW_X86_64_R15: _msContext.R15 = value; break;
737 #elif defined(_LIBUNWIND_TARGET_ARM)
738   case UNW_ARM_R0: _msContext.R0 = value; break;
739   case UNW_ARM_R1: _msContext.R1 = value; break;
740   case UNW_ARM_R2: _msContext.R2 = value; break;
741   case UNW_ARM_R3: _msContext.R3 = value; break;
742   case UNW_ARM_R4: _msContext.R4 = value; break;
743   case UNW_ARM_R5: _msContext.R5 = value; break;
744   case UNW_ARM_R6: _msContext.R6 = value; break;
745   case UNW_ARM_R7: _msContext.R7 = value; break;
746   case UNW_ARM_R8: _msContext.R8 = value; break;
747   case UNW_ARM_R9: _msContext.R9 = value; break;
748   case UNW_ARM_R10: _msContext.R10 = value; break;
749   case UNW_ARM_R11: _msContext.R11 = value; break;
750   case UNW_ARM_R12: _msContext.R12 = value; break;
751   case UNW_REG_SP:
752   case UNW_ARM_SP: _msContext.Sp = value; break;
753   case UNW_ARM_LR: _msContext.Lr = value; break;
754   case UNW_REG_IP:
755   case UNW_ARM_IP: _msContext.Pc = value; break;
756 #elif defined(_LIBUNWIND_TARGET_AARCH64)
757   case UNW_REG_SP: _msContext.Sp = value; break;
758   case UNW_REG_IP: _msContext.Pc = value; break;
759   case UNW_AARCH64_X0:
760   case UNW_AARCH64_X1:
761   case UNW_AARCH64_X2:
762   case UNW_AARCH64_X3:
763   case UNW_AARCH64_X4:
764   case UNW_AARCH64_X5:
765   case UNW_AARCH64_X6:
766   case UNW_AARCH64_X7:
767   case UNW_AARCH64_X8:
768   case UNW_AARCH64_X9:
769   case UNW_AARCH64_X10:
770   case UNW_AARCH64_X11:
771   case UNW_AARCH64_X12:
772   case UNW_AARCH64_X13:
773   case UNW_AARCH64_X14:
774   case UNW_AARCH64_X15:
775   case UNW_AARCH64_X16:
776   case UNW_AARCH64_X17:
777   case UNW_AARCH64_X18:
778   case UNW_AARCH64_X19:
779   case UNW_AARCH64_X20:
780   case UNW_AARCH64_X21:
781   case UNW_AARCH64_X22:
782   case UNW_AARCH64_X23:
783   case UNW_AARCH64_X24:
784   case UNW_AARCH64_X25:
785   case UNW_AARCH64_X26:
786   case UNW_AARCH64_X27:
787   case UNW_AARCH64_X28:
788   case UNW_AARCH64_FP:
789   case UNW_AARCH64_LR: _msContext.X[regNum - UNW_ARM64_X0] = value; break;
790 #endif
791   default:
792     _LIBUNWIND_ABORT("unsupported register");
793   }
794 }
795 
796 template <typename A, typename R>
validFloatReg(int regNum)797 bool UnwindCursor<A, R>::validFloatReg(int regNum) {
798 #if defined(_LIBUNWIND_TARGET_ARM)
799   if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) return true;
800   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) return true;
801 #elif defined(_LIBUNWIND_TARGET_AARCH64)
802   if (regNum >= UNW_AARCH64_V0 && regNum <= UNW_ARM64_D31) return true;
803 #else
804   (void)regNum;
805 #endif
806   return false;
807 }
808 
809 template <typename A, typename R>
getFloatReg(int regNum)810 unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
811 #if defined(_LIBUNWIND_TARGET_ARM)
812   if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) {
813     union {
814       uint32_t w;
815       float f;
816     } d;
817     d.w = _msContext.S[regNum - UNW_ARM_S0];
818     return d.f;
819   }
820   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {
821     union {
822       uint64_t w;
823       double d;
824     } d;
825     d.w = _msContext.D[regNum - UNW_ARM_D0];
826     return d.d;
827   }
828   _LIBUNWIND_ABORT("unsupported float register");
829 #elif defined(_LIBUNWIND_TARGET_AARCH64)
830   return _msContext.V[regNum - UNW_AARCH64_V0].D[0];
831 #else
832   (void)regNum;
833   _LIBUNWIND_ABORT("float registers unimplemented");
834 #endif
835 }
836 
837 template <typename A, typename R>
setFloatReg(int regNum,unw_fpreg_t value)838 void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
839 #if defined(_LIBUNWIND_TARGET_ARM)
840   if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) {
841     union {
842       uint32_t w;
843       float f;
844     } d;
845     d.f = value;
846     _msContext.S[regNum - UNW_ARM_S0] = d.w;
847   }
848   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {
849     union {
850       uint64_t w;
851       double d;
852     } d;
853     d.d = value;
854     _msContext.D[regNum - UNW_ARM_D0] = d.w;
855   }
856   _LIBUNWIND_ABORT("unsupported float register");
857 #elif defined(_LIBUNWIND_TARGET_AARCH64)
858   _msContext.V[regNum - UNW_AARCH64_V0].D[0] = value;
859 #else
860   (void)regNum;
861   (void)value;
862   _LIBUNWIND_ABORT("float registers unimplemented");
863 #endif
864 }
865 
jumpto()866 template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
867   RtlRestoreContext(&_msContext, nullptr);
868 }
869 
870 #ifdef __arm__
saveVFPAsX()871 template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {}
872 #endif
873 
874 template <typename A, typename R>
getRegisterName(int regNum)875 const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
876   return R::getRegisterName(regNum);
877 }
878 
isSignalFrame()879 template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
880   return false;
881 }
882 
883 #else  // !defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) || !defined(_WIN32)
884 
885 /// UnwindCursor contains all state (including all register values) during
886 /// an unwind.  This is normally stack allocated inside a unw_cursor_t.
887 template <typename A, typename R>
888 class UnwindCursor : public AbstractUnwindCursor{
889   typedef typename A::pint_t pint_t;
890 public:
891                       UnwindCursor(unw_context_t *context, A &as);
892                       UnwindCursor(A &as, void *threadArg);
~UnwindCursor()893   virtual             ~UnwindCursor() {}
894   virtual bool        validReg(int);
895   virtual unw_word_t  getReg(int);
896   virtual void        setReg(int, unw_word_t);
897   virtual bool        validFloatReg(int);
898   virtual unw_fpreg_t getFloatReg(int);
899   virtual void        setFloatReg(int, unw_fpreg_t);
900   virtual int         step();
901   virtual void        getInfo(unw_proc_info_t *);
902   virtual void        jumpto();
903   virtual bool        isSignalFrame();
904   virtual bool        getFunctionName(char *buf, size_t len, unw_word_t *off);
905   virtual void        setInfoBasedOnIPRegister(bool isReturnAddress = false);
906   virtual const char *getRegisterName(int num);
907 #ifdef __arm__
908   virtual void        saveVFPAsX();
909 #endif
910 
911 #if defined(_LIBUNWIND_USE_CET)
get_registers()912   virtual void *get_registers() { return &_registers; }
913 #endif
914   // libunwind does not and should not depend on C++ library which means that we
915   // need our own defition of inline placement new.
operator new(size_t,UnwindCursor<A,R> * p)916   static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
917 
918 private:
919 
920 #if defined(_LIBUNWIND_ARM_EHABI)
921   bool getInfoFromEHABISection(pint_t pc, const UnwindInfoSections &sects);
922 
stepWithEHABI()923   int stepWithEHABI() {
924     size_t len = 0;
925     size_t off = 0;
926     // FIXME: Calling decode_eht_entry() here is violating the libunwind
927     // abstraction layer.
928     const uint32_t *ehtp =
929         decode_eht_entry(reinterpret_cast<const uint32_t *>(_info.unwind_info),
930                          &off, &len);
931     if (_Unwind_VRS_Interpret((_Unwind_Context *)this, ehtp, off, len) !=
932             _URC_CONTINUE_UNWIND)
933       return UNW_STEP_END;
934     return UNW_STEP_SUCCESS;
935   }
936 #endif
937 
938 #if defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
setInfoForSigReturn()939   bool setInfoForSigReturn() {
940     R dummy;
941     return setInfoForSigReturn(dummy);
942   }
stepThroughSigReturn()943   int stepThroughSigReturn() {
944     R dummy;
945     return stepThroughSigReturn(dummy);
946   }
947   bool setInfoForSigReturn(Registers_arm64 &);
948   int stepThroughSigReturn(Registers_arm64 &);
setInfoForSigReturn(Registers &)949   template <typename Registers> bool setInfoForSigReturn(Registers &) {
950     return false;
951   }
stepThroughSigReturn(Registers &)952   template <typename Registers> int stepThroughSigReturn(Registers &) {
953     return UNW_STEP_END;
954   }
955 #endif
956 
957 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
958   bool getInfoFromFdeCie(const typename CFI_Parser<A>::FDE_Info &fdeInfo,
959                          const typename CFI_Parser<A>::CIE_Info &cieInfo,
960                          pint_t pc, uintptr_t dso_base);
961   bool getInfoFromDwarfSection(pint_t pc, const UnwindInfoSections &sects,
962                                             uint32_t fdeSectionOffsetHint=0);
stepWithDwarfFDE()963   int stepWithDwarfFDE() {
964     return DwarfInstructions<A, R>::stepWithDwarf(_addressSpace,
965                                               (pint_t)this->getReg(UNW_REG_IP),
966                                               (pint_t)_info.unwind_info,
967                                               _registers, _isSignalFrame);
968   }
969 #endif
970 
971 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
972   bool getInfoFromCompactEncodingSection(pint_t pc,
973                                             const UnwindInfoSections &sects);
stepWithCompactEncoding()974   int stepWithCompactEncoding() {
975   #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
976     if ( compactSaysUseDwarf() )
977       return stepWithDwarfFDE();
978   #endif
979     R dummy;
980     return stepWithCompactEncoding(dummy);
981   }
982 
983 #if defined(_LIBUNWIND_TARGET_X86_64)
stepWithCompactEncoding(Registers_x86_64 &)984   int stepWithCompactEncoding(Registers_x86_64 &) {
985     return CompactUnwinder_x86_64<A>::stepWithCompactEncoding(
986         _info.format, _info.start_ip, _addressSpace, _registers);
987   }
988 #endif
989 
990 #if defined(_LIBUNWIND_TARGET_I386)
stepWithCompactEncoding(Registers_x86 &)991   int stepWithCompactEncoding(Registers_x86 &) {
992     return CompactUnwinder_x86<A>::stepWithCompactEncoding(
993         _info.format, (uint32_t)_info.start_ip, _addressSpace, _registers);
994   }
995 #endif
996 
997 #if defined(_LIBUNWIND_TARGET_PPC)
stepWithCompactEncoding(Registers_ppc &)998   int stepWithCompactEncoding(Registers_ppc &) {
999     return UNW_EINVAL;
1000   }
1001 #endif
1002 
1003 #if defined(_LIBUNWIND_TARGET_PPC64)
stepWithCompactEncoding(Registers_ppc64 &)1004   int stepWithCompactEncoding(Registers_ppc64 &) {
1005     return UNW_EINVAL;
1006   }
1007 #endif
1008 
1009 
1010 #if defined(_LIBUNWIND_TARGET_AARCH64)
stepWithCompactEncoding(Registers_arm64 &)1011   int stepWithCompactEncoding(Registers_arm64 &) {
1012     return CompactUnwinder_arm64<A>::stepWithCompactEncoding(
1013         _info.format, _info.start_ip, _addressSpace, _registers);
1014   }
1015 #endif
1016 
1017 #if defined(_LIBUNWIND_TARGET_MIPS_O32)
stepWithCompactEncoding(Registers_mips_o32 &)1018   int stepWithCompactEncoding(Registers_mips_o32 &) {
1019     return UNW_EINVAL;
1020   }
1021 #endif
1022 
1023 #if defined(_LIBUNWIND_TARGET_MIPS_NEWABI)
stepWithCompactEncoding(Registers_mips_newabi &)1024   int stepWithCompactEncoding(Registers_mips_newabi &) {
1025     return UNW_EINVAL;
1026   }
1027 #endif
1028 
1029 #if defined(_LIBUNWIND_TARGET_SPARC)
stepWithCompactEncoding(Registers_sparc &)1030   int stepWithCompactEncoding(Registers_sparc &) { return UNW_EINVAL; }
1031 #endif
1032 
1033 #if defined (_LIBUNWIND_TARGET_RISCV)
stepWithCompactEncoding(Registers_riscv &)1034   int stepWithCompactEncoding(Registers_riscv &) {
1035     return UNW_EINVAL;
1036   }
1037 #endif
1038 
compactSaysUseDwarf(uint32_t * offset=NULL) const1039   bool compactSaysUseDwarf(uint32_t *offset=NULL) const {
1040     R dummy;
1041     return compactSaysUseDwarf(dummy, offset);
1042   }
1043 
1044 #if defined(_LIBUNWIND_TARGET_X86_64)
compactSaysUseDwarf(Registers_x86_64 &,uint32_t * offset) const1045   bool compactSaysUseDwarf(Registers_x86_64 &, uint32_t *offset) const {
1046     if ((_info.format & UNWIND_X86_64_MODE_MASK) == UNWIND_X86_64_MODE_DWARF) {
1047       if (offset)
1048         *offset = (_info.format & UNWIND_X86_64_DWARF_SECTION_OFFSET);
1049       return true;
1050     }
1051     return false;
1052   }
1053 #endif
1054 
1055 #if defined(_LIBUNWIND_TARGET_I386)
compactSaysUseDwarf(Registers_x86 &,uint32_t * offset) const1056   bool compactSaysUseDwarf(Registers_x86 &, uint32_t *offset) const {
1057     if ((_info.format & UNWIND_X86_MODE_MASK) == UNWIND_X86_MODE_DWARF) {
1058       if (offset)
1059         *offset = (_info.format & UNWIND_X86_DWARF_SECTION_OFFSET);
1060       return true;
1061     }
1062     return false;
1063   }
1064 #endif
1065 
1066 #if defined(_LIBUNWIND_TARGET_PPC)
compactSaysUseDwarf(Registers_ppc &,uint32_t *) const1067   bool compactSaysUseDwarf(Registers_ppc &, uint32_t *) const {
1068     return true;
1069   }
1070 #endif
1071 
1072 #if defined(_LIBUNWIND_TARGET_PPC64)
compactSaysUseDwarf(Registers_ppc64 &,uint32_t *) const1073   bool compactSaysUseDwarf(Registers_ppc64 &, uint32_t *) const {
1074     return true;
1075   }
1076 #endif
1077 
1078 #if defined(_LIBUNWIND_TARGET_AARCH64)
compactSaysUseDwarf(Registers_arm64 &,uint32_t * offset) const1079   bool compactSaysUseDwarf(Registers_arm64 &, uint32_t *offset) const {
1080     if ((_info.format & UNWIND_ARM64_MODE_MASK) == UNWIND_ARM64_MODE_DWARF) {
1081       if (offset)
1082         *offset = (_info.format & UNWIND_ARM64_DWARF_SECTION_OFFSET);
1083       return true;
1084     }
1085     return false;
1086   }
1087 #endif
1088 
1089 #if defined(_LIBUNWIND_TARGET_MIPS_O32)
compactSaysUseDwarf(Registers_mips_o32 &,uint32_t *) const1090   bool compactSaysUseDwarf(Registers_mips_o32 &, uint32_t *) const {
1091     return true;
1092   }
1093 #endif
1094 
1095 #if defined(_LIBUNWIND_TARGET_MIPS_NEWABI)
compactSaysUseDwarf(Registers_mips_newabi &,uint32_t *) const1096   bool compactSaysUseDwarf(Registers_mips_newabi &, uint32_t *) const {
1097     return true;
1098   }
1099 #endif
1100 
1101 #if defined(_LIBUNWIND_TARGET_SPARC)
compactSaysUseDwarf(Registers_sparc &,uint32_t *) const1102   bool compactSaysUseDwarf(Registers_sparc &, uint32_t *) const { return true; }
1103 #endif
1104 
1105 #if defined (_LIBUNWIND_TARGET_RISCV)
compactSaysUseDwarf(Registers_riscv &,uint32_t *) const1106   bool compactSaysUseDwarf(Registers_riscv &, uint32_t *) const {
1107     return true;
1108   }
1109 #endif
1110 
1111 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1112 
1113 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
dwarfEncoding() const1114   compact_unwind_encoding_t dwarfEncoding() const {
1115     R dummy;
1116     return dwarfEncoding(dummy);
1117   }
1118 
1119 #if defined(_LIBUNWIND_TARGET_X86_64)
dwarfEncoding(Registers_x86_64 &) const1120   compact_unwind_encoding_t dwarfEncoding(Registers_x86_64 &) const {
1121     return UNWIND_X86_64_MODE_DWARF;
1122   }
1123 #endif
1124 
1125 #if defined(_LIBUNWIND_TARGET_I386)
dwarfEncoding(Registers_x86 &) const1126   compact_unwind_encoding_t dwarfEncoding(Registers_x86 &) const {
1127     return UNWIND_X86_MODE_DWARF;
1128   }
1129 #endif
1130 
1131 #if defined(_LIBUNWIND_TARGET_PPC)
dwarfEncoding(Registers_ppc &) const1132   compact_unwind_encoding_t dwarfEncoding(Registers_ppc &) const {
1133     return 0;
1134   }
1135 #endif
1136 
1137 #if defined(_LIBUNWIND_TARGET_PPC64)
dwarfEncoding(Registers_ppc64 &) const1138   compact_unwind_encoding_t dwarfEncoding(Registers_ppc64 &) const {
1139     return 0;
1140   }
1141 #endif
1142 
1143 #if defined(_LIBUNWIND_TARGET_AARCH64)
dwarfEncoding(Registers_arm64 &) const1144   compact_unwind_encoding_t dwarfEncoding(Registers_arm64 &) const {
1145     return UNWIND_ARM64_MODE_DWARF;
1146   }
1147 #endif
1148 
1149 #if defined(_LIBUNWIND_TARGET_ARM)
dwarfEncoding(Registers_arm &) const1150   compact_unwind_encoding_t dwarfEncoding(Registers_arm &) const {
1151     return 0;
1152   }
1153 #endif
1154 
1155 #if defined (_LIBUNWIND_TARGET_OR1K)
dwarfEncoding(Registers_or1k &) const1156   compact_unwind_encoding_t dwarfEncoding(Registers_or1k &) const {
1157     return 0;
1158   }
1159 #endif
1160 
1161 #if defined (_LIBUNWIND_TARGET_HEXAGON)
dwarfEncoding(Registers_hexagon &) const1162   compact_unwind_encoding_t dwarfEncoding(Registers_hexagon &) const {
1163     return 0;
1164   }
1165 #endif
1166 
1167 #if defined (_LIBUNWIND_TARGET_MIPS_O32)
dwarfEncoding(Registers_mips_o32 &) const1168   compact_unwind_encoding_t dwarfEncoding(Registers_mips_o32 &) const {
1169     return 0;
1170   }
1171 #endif
1172 
1173 #if defined (_LIBUNWIND_TARGET_MIPS_NEWABI)
dwarfEncoding(Registers_mips_newabi &) const1174   compact_unwind_encoding_t dwarfEncoding(Registers_mips_newabi &) const {
1175     return 0;
1176   }
1177 #endif
1178 
1179 #if defined(_LIBUNWIND_TARGET_SPARC)
dwarfEncoding(Registers_sparc &) const1180   compact_unwind_encoding_t dwarfEncoding(Registers_sparc &) const { return 0; }
1181 #endif
1182 
1183 #if defined (_LIBUNWIND_TARGET_RISCV)
dwarfEncoding(Registers_riscv &) const1184   compact_unwind_encoding_t dwarfEncoding(Registers_riscv &) const {
1185     return 0;
1186   }
1187 #endif
1188 
1189 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1190 
1191 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1192   // For runtime environments using SEH unwind data without Windows runtime
1193   // support.
getLastPC() const1194   pint_t getLastPC() const { /* FIXME: Implement */ return 0; }
setLastPC(pint_t pc)1195   void setLastPC(pint_t pc) { /* FIXME: Implement */ }
lookUpSEHUnwindInfo(pint_t pc,pint_t * base)1196   RUNTIME_FUNCTION *lookUpSEHUnwindInfo(pint_t pc, pint_t *base) {
1197     /* FIXME: Implement */
1198     *base = 0;
1199     return nullptr;
1200   }
1201   bool getInfoFromSEH(pint_t pc);
stepWithSEHData()1202   int stepWithSEHData() { /* FIXME: Implement */ return 0; }
1203 #endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1204 
1205 
1206   A               &_addressSpace;
1207   R                _registers;
1208   unw_proc_info_t  _info;
1209   bool             _unwindInfoMissing;
1210   bool             _isSignalFrame;
1211 #if defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
1212   bool             _isSigReturn = false;
1213 #endif
1214 };
1215 
1216 
1217 template <typename A, typename R>
UnwindCursor(unw_context_t * context,A & as)1218 UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
1219     : _addressSpace(as), _registers(context), _unwindInfoMissing(false),
1220       _isSignalFrame(false) {
1221   static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
1222                 "UnwindCursor<> does not fit in unw_cursor_t");
1223   static_assert((alignof(UnwindCursor<A, R>) <= alignof(unw_cursor_t)),
1224                 "UnwindCursor<> requires more alignment than unw_cursor_t");
1225   memset(&_info, 0, sizeof(_info));
1226 }
1227 
1228 template <typename A, typename R>
UnwindCursor(A & as,void *)1229 UnwindCursor<A, R>::UnwindCursor(A &as, void *)
1230     : _addressSpace(as), _unwindInfoMissing(false), _isSignalFrame(false) {
1231   memset(&_info, 0, sizeof(_info));
1232   // FIXME
1233   // fill in _registers from thread arg
1234 }
1235 
1236 
1237 template <typename A, typename R>
validReg(int regNum)1238 bool UnwindCursor<A, R>::validReg(int regNum) {
1239   return _registers.validRegister(regNum);
1240 }
1241 
1242 template <typename A, typename R>
getReg(int regNum)1243 unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
1244   return _registers.getRegister(regNum);
1245 }
1246 
1247 template <typename A, typename R>
setReg(int regNum,unw_word_t value)1248 void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
1249   _registers.setRegister(regNum, (typename A::pint_t)value);
1250 }
1251 
1252 template <typename A, typename R>
validFloatReg(int regNum)1253 bool UnwindCursor<A, R>::validFloatReg(int regNum) {
1254   return _registers.validFloatRegister(regNum);
1255 }
1256 
1257 template <typename A, typename R>
getFloatReg(int regNum)1258 unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
1259   return _registers.getFloatRegister(regNum);
1260 }
1261 
1262 template <typename A, typename R>
setFloatReg(int regNum,unw_fpreg_t value)1263 void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
1264   _registers.setFloatRegister(regNum, value);
1265 }
1266 
jumpto()1267 template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
1268   _registers.jumpto();
1269 }
1270 
1271 #ifdef __arm__
saveVFPAsX()1272 template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {
1273   _registers.saveVFPAsX();
1274 }
1275 #endif
1276 
1277 template <typename A, typename R>
getRegisterName(int regNum)1278 const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
1279   return _registers.getRegisterName(regNum);
1280 }
1281 
isSignalFrame()1282 template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
1283   return _isSignalFrame;
1284 }
1285 
1286 #endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1287 
1288 #if defined(_LIBUNWIND_ARM_EHABI)
1289 template<typename A>
1290 struct EHABISectionIterator {
1291   typedef EHABISectionIterator _Self;
1292 
1293   typedef typename A::pint_t value_type;
1294   typedef typename A::pint_t* pointer;
1295   typedef typename A::pint_t& reference;
1296   typedef size_t size_type;
1297   typedef size_t difference_type;
1298 
beginlibunwind::EHABISectionIterator1299   static _Self begin(A& addressSpace, const UnwindInfoSections& sects) {
1300     return _Self(addressSpace, sects, 0);
1301   }
endlibunwind::EHABISectionIterator1302   static _Self end(A& addressSpace, const UnwindInfoSections& sects) {
1303     return _Self(addressSpace, sects,
1304                  sects.arm_section_length / sizeof(EHABIIndexEntry));
1305   }
1306 
EHABISectionIteratorlibunwind::EHABISectionIterator1307   EHABISectionIterator(A& addressSpace, const UnwindInfoSections& sects, size_t i)
1308       : _i(i), _addressSpace(&addressSpace), _sects(&sects) {}
1309 
operator ++libunwind::EHABISectionIterator1310   _Self& operator++() { ++_i; return *this; }
operator +=libunwind::EHABISectionIterator1311   _Self& operator+=(size_t a) { _i += a; return *this; }
operator --libunwind::EHABISectionIterator1312   _Self& operator--() { assert(_i > 0); --_i; return *this; }
operator -=libunwind::EHABISectionIterator1313   _Self& operator-=(size_t a) { assert(_i >= a); _i -= a; return *this; }
1314 
operator +libunwind::EHABISectionIterator1315   _Self operator+(size_t a) { _Self out = *this; out._i += a; return out; }
operator -libunwind::EHABISectionIterator1316   _Self operator-(size_t a) { assert(_i >= a); _Self out = *this; out._i -= a; return out; }
1317 
operator -libunwind::EHABISectionIterator1318   size_t operator-(const _Self& other) const { return _i - other._i; }
1319 
operator ==libunwind::EHABISectionIterator1320   bool operator==(const _Self& other) const {
1321     assert(_addressSpace == other._addressSpace);
1322     assert(_sects == other._sects);
1323     return _i == other._i;
1324   }
1325 
operator !=libunwind::EHABISectionIterator1326   bool operator!=(const _Self& other) const {
1327     assert(_addressSpace == other._addressSpace);
1328     assert(_sects == other._sects);
1329     return _i != other._i;
1330   }
1331 
operator *libunwind::EHABISectionIterator1332   typename A::pint_t operator*() const { return functionAddress(); }
1333 
functionAddresslibunwind::EHABISectionIterator1334   typename A::pint_t functionAddress() const {
1335     typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
1336         EHABIIndexEntry, _i, functionOffset);
1337     return indexAddr + signExtendPrel31(_addressSpace->get32(indexAddr));
1338   }
1339 
dataAddresslibunwind::EHABISectionIterator1340   typename A::pint_t dataAddress() {
1341     typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
1342         EHABIIndexEntry, _i, data);
1343     return indexAddr;
1344   }
1345 
1346  private:
1347   size_t _i;
1348   A* _addressSpace;
1349   const UnwindInfoSections* _sects;
1350 };
1351 
1352 namespace {
1353 
1354 template <typename A>
EHABISectionUpperBound(EHABISectionIterator<A> first,EHABISectionIterator<A> last,typename A::pint_t value)1355 EHABISectionIterator<A> EHABISectionUpperBound(
1356     EHABISectionIterator<A> first,
1357     EHABISectionIterator<A> last,
1358     typename A::pint_t value) {
1359   size_t len = last - first;
1360   while (len > 0) {
1361     size_t l2 = len / 2;
1362     EHABISectionIterator<A> m = first + l2;
1363     if (value < *m) {
1364         len = l2;
1365     } else {
1366         first = ++m;
1367         len -= l2 + 1;
1368     }
1369   }
1370   return first;
1371 }
1372 
1373 }
1374 
1375 template <typename A, typename R>
getInfoFromEHABISection(pint_t pc,const UnwindInfoSections & sects)1376 bool UnwindCursor<A, R>::getInfoFromEHABISection(
1377     pint_t pc,
1378     const UnwindInfoSections &sects) {
1379   EHABISectionIterator<A> begin =
1380       EHABISectionIterator<A>::begin(_addressSpace, sects);
1381   EHABISectionIterator<A> end =
1382       EHABISectionIterator<A>::end(_addressSpace, sects);
1383   if (begin == end)
1384     return false;
1385 
1386   EHABISectionIterator<A> itNextPC = EHABISectionUpperBound(begin, end, pc);
1387   if (itNextPC == begin)
1388     return false;
1389   EHABISectionIterator<A> itThisPC = itNextPC - 1;
1390 
1391   pint_t thisPC = itThisPC.functionAddress();
1392   // If an exception is thrown from a function, corresponding to the last entry
1393   // in the table, we don't really know the function extent and have to choose a
1394   // value for nextPC. Choosing max() will allow the range check during trace to
1395   // succeed.
1396   pint_t nextPC = (itNextPC == end) ? UINTPTR_MAX : itNextPC.functionAddress();
1397   pint_t indexDataAddr = itThisPC.dataAddress();
1398 
1399   if (indexDataAddr == 0)
1400     return false;
1401 
1402   uint32_t indexData = _addressSpace.get32(indexDataAddr);
1403   if (indexData == UNW_EXIDX_CANTUNWIND)
1404     return false;
1405 
1406   // If the high bit is set, the exception handling table entry is inline inside
1407   // the index table entry on the second word (aka |indexDataAddr|). Otherwise,
1408   // the table points at an offset in the exception handling table (section 5
1409   // EHABI).
1410   pint_t exceptionTableAddr;
1411   uint32_t exceptionTableData;
1412   bool isSingleWordEHT;
1413   if (indexData & 0x80000000) {
1414     exceptionTableAddr = indexDataAddr;
1415     // TODO(ajwong): Should this data be 0?
1416     exceptionTableData = indexData;
1417     isSingleWordEHT = true;
1418   } else {
1419     exceptionTableAddr = indexDataAddr + signExtendPrel31(indexData);
1420     exceptionTableData = _addressSpace.get32(exceptionTableAddr);
1421     isSingleWordEHT = false;
1422   }
1423 
1424   // Now we know the 3 things:
1425   //   exceptionTableAddr -- exception handler table entry.
1426   //   exceptionTableData -- the data inside the first word of the eht entry.
1427   //   isSingleWordEHT -- whether the entry is in the index.
1428   unw_word_t personalityRoutine = 0xbadf00d;
1429   bool scope32 = false;
1430   uintptr_t lsda;
1431 
1432   // If the high bit in the exception handling table entry is set, the entry is
1433   // in compact form (section 6.3 EHABI).
1434   if (exceptionTableData & 0x80000000) {
1435     // Grab the index of the personality routine from the compact form.
1436     uint32_t choice = (exceptionTableData & 0x0f000000) >> 24;
1437     uint32_t extraWords = 0;
1438     switch (choice) {
1439       case 0:
1440         personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr0;
1441         extraWords = 0;
1442         scope32 = false;
1443         lsda = isSingleWordEHT ? 0 : (exceptionTableAddr + 4);
1444         break;
1445       case 1:
1446         personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr1;
1447         extraWords = (exceptionTableData & 0x00ff0000) >> 16;
1448         scope32 = false;
1449         lsda = exceptionTableAddr + (extraWords + 1) * 4;
1450         break;
1451       case 2:
1452         personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr2;
1453         extraWords = (exceptionTableData & 0x00ff0000) >> 16;
1454         scope32 = true;
1455         lsda = exceptionTableAddr + (extraWords + 1) * 4;
1456         break;
1457       default:
1458         _LIBUNWIND_ABORT("unknown personality routine");
1459         return false;
1460     }
1461 
1462     if (isSingleWordEHT) {
1463       if (extraWords != 0) {
1464         _LIBUNWIND_ABORT("index inlined table detected but pr function "
1465                          "requires extra words");
1466         return false;
1467       }
1468     }
1469   } else {
1470     pint_t personalityAddr =
1471         exceptionTableAddr + signExtendPrel31(exceptionTableData);
1472     personalityRoutine = personalityAddr;
1473 
1474     // ARM EHABI # 6.2, # 9.2
1475     //
1476     //  +---- ehtp
1477     //  v
1478     // +--------------------------------------+
1479     // | +--------+--------+--------+-------+ |
1480     // | |0| prel31 to personalityRoutine   | |
1481     // | +--------+--------+--------+-------+ |
1482     // | |      N |      unwind opcodes     | |  <-- UnwindData
1483     // | +--------+--------+--------+-------+ |
1484     // | | Word 2        unwind opcodes     | |
1485     // | +--------+--------+--------+-------+ |
1486     // | ...                                  |
1487     // | +--------+--------+--------+-------+ |
1488     // | | Word N        unwind opcodes     | |
1489     // | +--------+--------+--------+-------+ |
1490     // | | LSDA                             | |  <-- lsda
1491     // | | ...                              | |
1492     // | +--------+--------+--------+-------+ |
1493     // +--------------------------------------+
1494 
1495     uint32_t *UnwindData = reinterpret_cast<uint32_t*>(exceptionTableAddr) + 1;
1496     uint32_t FirstDataWord = *UnwindData;
1497     size_t N = ((FirstDataWord >> 24) & 0xff);
1498     size_t NDataWords = N + 1;
1499     lsda = reinterpret_cast<uintptr_t>(UnwindData + NDataWords);
1500   }
1501 
1502   _info.start_ip = thisPC;
1503   _info.end_ip = nextPC;
1504   _info.handler = personalityRoutine;
1505   _info.unwind_info = exceptionTableAddr;
1506   _info.lsda = lsda;
1507   // flags is pr_cache.additional. See EHABI #7.2 for definition of bit 0.
1508   _info.flags = (isSingleWordEHT ? 1 : 0) | (scope32 ? 0x2 : 0);  // Use enum?
1509 
1510   return true;
1511 }
1512 #endif
1513 
1514 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1515 template <typename A, typename R>
getInfoFromFdeCie(const typename CFI_Parser<A>::FDE_Info & fdeInfo,const typename CFI_Parser<A>::CIE_Info & cieInfo,pint_t pc,uintptr_t dso_base)1516 bool UnwindCursor<A, R>::getInfoFromFdeCie(
1517     const typename CFI_Parser<A>::FDE_Info &fdeInfo,
1518     const typename CFI_Parser<A>::CIE_Info &cieInfo, pint_t pc,
1519     uintptr_t dso_base) {
1520   typename CFI_Parser<A>::PrologInfo prolog;
1521   if (CFI_Parser<A>::parseFDEInstructions(_addressSpace, fdeInfo, cieInfo, pc,
1522                                           R::getArch(), &prolog)) {
1523     // Save off parsed FDE info
1524     _info.start_ip          = fdeInfo.pcStart;
1525     _info.end_ip            = fdeInfo.pcEnd;
1526     _info.lsda              = fdeInfo.lsda;
1527     _info.handler           = cieInfo.personality;
1528     // Some frameless functions need SP altered when resuming in function, so
1529     // propagate spExtraArgSize.
1530     _info.gp                = prolog.spExtraArgSize;
1531     _info.flags             = 0;
1532     _info.format            = dwarfEncoding();
1533     _info.unwind_info       = fdeInfo.fdeStart;
1534     _info.unwind_info_size  = static_cast<uint32_t>(fdeInfo.fdeLength);
1535     _info.extra             = static_cast<unw_word_t>(dso_base);
1536     return true;
1537   }
1538   return false;
1539 }
1540 
1541 template <typename A, typename R>
getInfoFromDwarfSection(pint_t pc,const UnwindInfoSections & sects,uint32_t fdeSectionOffsetHint)1542 bool UnwindCursor<A, R>::getInfoFromDwarfSection(pint_t pc,
1543                                                 const UnwindInfoSections &sects,
1544                                                 uint32_t fdeSectionOffsetHint) {
1545   typename CFI_Parser<A>::FDE_Info fdeInfo;
1546   typename CFI_Parser<A>::CIE_Info cieInfo;
1547   bool foundFDE = false;
1548   bool foundInCache = false;
1549   // If compact encoding table gave offset into dwarf section, go directly there
1550   if (fdeSectionOffsetHint != 0) {
1551     foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1552                                     sects.dwarf_section_length,
1553                                     sects.dwarf_section + fdeSectionOffsetHint,
1554                                     &fdeInfo, &cieInfo);
1555   }
1556 #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
1557   if (!foundFDE && (sects.dwarf_index_section != 0)) {
1558     foundFDE = EHHeaderParser<A>::findFDE(
1559         _addressSpace, pc, sects.dwarf_index_section,
1560         (uint32_t)sects.dwarf_index_section_length, &fdeInfo, &cieInfo);
1561   }
1562 #endif
1563   if (!foundFDE) {
1564     // otherwise, search cache of previously found FDEs.
1565     pint_t cachedFDE = DwarfFDECache<A>::findFDE(sects.dso_base, pc);
1566     if (cachedFDE != 0) {
1567       foundFDE =
1568           CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1569                                  sects.dwarf_section_length,
1570                                  cachedFDE, &fdeInfo, &cieInfo);
1571       foundInCache = foundFDE;
1572     }
1573   }
1574   if (!foundFDE) {
1575     // Still not found, do full scan of __eh_frame section.
1576     foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1577                                       sects.dwarf_section_length, 0,
1578                                       &fdeInfo, &cieInfo);
1579   }
1580   if (foundFDE) {
1581     if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, sects.dso_base)) {
1582       // Add to cache (to make next lookup faster) if we had no hint
1583       // and there was no index.
1584       if (!foundInCache && (fdeSectionOffsetHint == 0)) {
1585   #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
1586         if (sects.dwarf_index_section == 0)
1587   #endif
1588         DwarfFDECache<A>::add(sects.dso_base, fdeInfo.pcStart, fdeInfo.pcEnd,
1589                               fdeInfo.fdeStart);
1590       }
1591       return true;
1592     }
1593   }
1594   //_LIBUNWIND_DEBUG_LOG("can't find/use FDE for pc=0x%llX", (uint64_t)pc);
1595   return false;
1596 }
1597 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1598 
1599 
1600 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1601 template <typename A, typename R>
getInfoFromCompactEncodingSection(pint_t pc,const UnwindInfoSections & sects)1602 bool UnwindCursor<A, R>::getInfoFromCompactEncodingSection(pint_t pc,
1603                                               const UnwindInfoSections &sects) {
1604   const bool log = false;
1605   if (log)
1606     fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX, mh=0x%llX)\n",
1607             (uint64_t)pc, (uint64_t)sects.dso_base);
1608 
1609   const UnwindSectionHeader<A> sectionHeader(_addressSpace,
1610                                                 sects.compact_unwind_section);
1611   if (sectionHeader.version() != UNWIND_SECTION_VERSION)
1612     return false;
1613 
1614   // do a binary search of top level index to find page with unwind info
1615   pint_t targetFunctionOffset = pc - sects.dso_base;
1616   const UnwindSectionIndexArray<A> topIndex(_addressSpace,
1617                                            sects.compact_unwind_section
1618                                          + sectionHeader.indexSectionOffset());
1619   uint32_t low = 0;
1620   uint32_t high = sectionHeader.indexCount();
1621   uint32_t last = high - 1;
1622   while (low < high) {
1623     uint32_t mid = (low + high) / 2;
1624     //if ( log ) fprintf(stderr, "\tmid=%d, low=%d, high=%d, *mid=0x%08X\n",
1625     //mid, low, high, topIndex.functionOffset(mid));
1626     if (topIndex.functionOffset(mid) <= targetFunctionOffset) {
1627       if ((mid == last) ||
1628           (topIndex.functionOffset(mid + 1) > targetFunctionOffset)) {
1629         low = mid;
1630         break;
1631       } else {
1632         low = mid + 1;
1633       }
1634     } else {
1635       high = mid;
1636     }
1637   }
1638   const uint32_t firstLevelFunctionOffset = topIndex.functionOffset(low);
1639   const uint32_t firstLevelNextPageFunctionOffset =
1640       topIndex.functionOffset(low + 1);
1641   const pint_t secondLevelAddr =
1642       sects.compact_unwind_section + topIndex.secondLevelPagesSectionOffset(low);
1643   const pint_t lsdaArrayStartAddr =
1644       sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low);
1645   const pint_t lsdaArrayEndAddr =
1646       sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low+1);
1647   if (log)
1648     fprintf(stderr, "\tfirst level search for result index=%d "
1649                     "to secondLevelAddr=0x%llX\n",
1650                     low, (uint64_t) secondLevelAddr);
1651   // do a binary search of second level page index
1652   uint32_t encoding = 0;
1653   pint_t funcStart = 0;
1654   pint_t funcEnd = 0;
1655   pint_t lsda = 0;
1656   pint_t personality = 0;
1657   uint32_t pageKind = _addressSpace.get32(secondLevelAddr);
1658   if (pageKind == UNWIND_SECOND_LEVEL_REGULAR) {
1659     // regular page
1660     UnwindSectionRegularPageHeader<A> pageHeader(_addressSpace,
1661                                                  secondLevelAddr);
1662     UnwindSectionRegularArray<A> pageIndex(
1663         _addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
1664     // binary search looks for entry with e where index[e].offset <= pc <
1665     // index[e+1].offset
1666     if (log)
1667       fprintf(stderr, "\tbinary search for targetFunctionOffset=0x%08llX in "
1668                       "regular page starting at secondLevelAddr=0x%llX\n",
1669               (uint64_t) targetFunctionOffset, (uint64_t) secondLevelAddr);
1670     low = 0;
1671     high = pageHeader.entryCount();
1672     while (low < high) {
1673       uint32_t mid = (low + high) / 2;
1674       if (pageIndex.functionOffset(mid) <= targetFunctionOffset) {
1675         if (mid == (uint32_t)(pageHeader.entryCount() - 1)) {
1676           // at end of table
1677           low = mid;
1678           funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
1679           break;
1680         } else if (pageIndex.functionOffset(mid + 1) > targetFunctionOffset) {
1681           // next is too big, so we found it
1682           low = mid;
1683           funcEnd = pageIndex.functionOffset(low + 1) + sects.dso_base;
1684           break;
1685         } else {
1686           low = mid + 1;
1687         }
1688       } else {
1689         high = mid;
1690       }
1691     }
1692     encoding = pageIndex.encoding(low);
1693     funcStart = pageIndex.functionOffset(low) + sects.dso_base;
1694     if (pc < funcStart) {
1695       if (log)
1696         fprintf(
1697             stderr,
1698             "\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
1699             (uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
1700       return false;
1701     }
1702     if (pc > funcEnd) {
1703       if (log)
1704         fprintf(
1705             stderr,
1706             "\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
1707             (uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
1708       return false;
1709     }
1710   } else if (pageKind == UNWIND_SECOND_LEVEL_COMPRESSED) {
1711     // compressed page
1712     UnwindSectionCompressedPageHeader<A> pageHeader(_addressSpace,
1713                                                     secondLevelAddr);
1714     UnwindSectionCompressedArray<A> pageIndex(
1715         _addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
1716     const uint32_t targetFunctionPageOffset =
1717         (uint32_t)(targetFunctionOffset - firstLevelFunctionOffset);
1718     // binary search looks for entry with e where index[e].offset <= pc <
1719     // index[e+1].offset
1720     if (log)
1721       fprintf(stderr, "\tbinary search of compressed page starting at "
1722                       "secondLevelAddr=0x%llX\n",
1723               (uint64_t) secondLevelAddr);
1724     low = 0;
1725     last = pageHeader.entryCount() - 1;
1726     high = pageHeader.entryCount();
1727     while (low < high) {
1728       uint32_t mid = (low + high) / 2;
1729       if (pageIndex.functionOffset(mid) <= targetFunctionPageOffset) {
1730         if ((mid == last) ||
1731             (pageIndex.functionOffset(mid + 1) > targetFunctionPageOffset)) {
1732           low = mid;
1733           break;
1734         } else {
1735           low = mid + 1;
1736         }
1737       } else {
1738         high = mid;
1739       }
1740     }
1741     funcStart = pageIndex.functionOffset(low) + firstLevelFunctionOffset
1742                                                               + sects.dso_base;
1743     if (low < last)
1744       funcEnd =
1745           pageIndex.functionOffset(low + 1) + firstLevelFunctionOffset
1746                                                               + sects.dso_base;
1747     else
1748       funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
1749     if (pc < funcStart) {
1750       _LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX "
1751                            "not in second level compressed unwind table. "
1752                            "funcStart=0x%llX",
1753                             (uint64_t) pc, (uint64_t) funcStart);
1754       return false;
1755     }
1756     if (pc > funcEnd) {
1757       _LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX "
1758                            "not in second level compressed unwind table. "
1759                            "funcEnd=0x%llX",
1760                            (uint64_t) pc, (uint64_t) funcEnd);
1761       return false;
1762     }
1763     uint16_t encodingIndex = pageIndex.encodingIndex(low);
1764     if (encodingIndex < sectionHeader.commonEncodingsArrayCount()) {
1765       // encoding is in common table in section header
1766       encoding = _addressSpace.get32(
1767           sects.compact_unwind_section +
1768           sectionHeader.commonEncodingsArraySectionOffset() +
1769           encodingIndex * sizeof(uint32_t));
1770     } else {
1771       // encoding is in page specific table
1772       uint16_t pageEncodingIndex =
1773           encodingIndex - (uint16_t)sectionHeader.commonEncodingsArrayCount();
1774       encoding = _addressSpace.get32(secondLevelAddr +
1775                                      pageHeader.encodingsPageOffset() +
1776                                      pageEncodingIndex * sizeof(uint32_t));
1777     }
1778   } else {
1779     _LIBUNWIND_DEBUG_LOG(
1780         "malformed __unwind_info at 0x%0llX bad second level page",
1781         (uint64_t)sects.compact_unwind_section);
1782     return false;
1783   }
1784 
1785   // look up LSDA, if encoding says function has one
1786   if (encoding & UNWIND_HAS_LSDA) {
1787     UnwindSectionLsdaArray<A> lsdaIndex(_addressSpace, lsdaArrayStartAddr);
1788     uint32_t funcStartOffset = (uint32_t)(funcStart - sects.dso_base);
1789     low = 0;
1790     high = (uint32_t)(lsdaArrayEndAddr - lsdaArrayStartAddr) /
1791                     sizeof(unwind_info_section_header_lsda_index_entry);
1792     // binary search looks for entry with exact match for functionOffset
1793     if (log)
1794       fprintf(stderr,
1795               "\tbinary search of lsda table for targetFunctionOffset=0x%08X\n",
1796               funcStartOffset);
1797     while (low < high) {
1798       uint32_t mid = (low + high) / 2;
1799       if (lsdaIndex.functionOffset(mid) == funcStartOffset) {
1800         lsda = lsdaIndex.lsdaOffset(mid) + sects.dso_base;
1801         break;
1802       } else if (lsdaIndex.functionOffset(mid) < funcStartOffset) {
1803         low = mid + 1;
1804       } else {
1805         high = mid;
1806       }
1807     }
1808     if (lsda == 0) {
1809       _LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with HAS_LSDA bit set for "
1810                     "pc=0x%0llX, but lsda table has no entry",
1811                     encoding, (uint64_t) pc);
1812       return false;
1813     }
1814   }
1815 
1816   // extract personality routine, if encoding says function has one
1817   uint32_t personalityIndex = (encoding & UNWIND_PERSONALITY_MASK) >>
1818                               (__builtin_ctz(UNWIND_PERSONALITY_MASK));
1819   if (personalityIndex != 0) {
1820     --personalityIndex; // change 1-based to zero-based index
1821     if (personalityIndex >= sectionHeader.personalityArrayCount()) {
1822       _LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with personality index %d,  "
1823                             "but personality table has only %d entries",
1824                             encoding, personalityIndex,
1825                             sectionHeader.personalityArrayCount());
1826       return false;
1827     }
1828     int32_t personalityDelta = (int32_t)_addressSpace.get32(
1829         sects.compact_unwind_section +
1830         sectionHeader.personalityArraySectionOffset() +
1831         personalityIndex * sizeof(uint32_t));
1832     pint_t personalityPointer = sects.dso_base + (pint_t)personalityDelta;
1833     personality = _addressSpace.getP(personalityPointer);
1834     if (log)
1835       fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
1836                       "personalityDelta=0x%08X, personality=0x%08llX\n",
1837               (uint64_t) pc, personalityDelta, (uint64_t) personality);
1838   }
1839 
1840   if (log)
1841     fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
1842                     "encoding=0x%08X, lsda=0x%08llX for funcStart=0x%llX\n",
1843             (uint64_t) pc, encoding, (uint64_t) lsda, (uint64_t) funcStart);
1844   _info.start_ip = funcStart;
1845   _info.end_ip = funcEnd;
1846   _info.lsda = lsda;
1847   _info.handler = personality;
1848   _info.gp = 0;
1849   _info.flags = 0;
1850   _info.format = encoding;
1851   _info.unwind_info = 0;
1852   _info.unwind_info_size = 0;
1853   _info.extra = sects.dso_base;
1854   return true;
1855 }
1856 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1857 
1858 
1859 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1860 template <typename A, typename R>
getInfoFromSEH(pint_t pc)1861 bool UnwindCursor<A, R>::getInfoFromSEH(pint_t pc) {
1862   pint_t base;
1863   RUNTIME_FUNCTION *unwindEntry = lookUpSEHUnwindInfo(pc, &base);
1864   if (!unwindEntry) {
1865     _LIBUNWIND_DEBUG_LOG("\tpc not in table, pc=0x%llX", (uint64_t) pc);
1866     return false;
1867   }
1868   _info.gp = 0;
1869   _info.flags = 0;
1870   _info.format = 0;
1871   _info.unwind_info_size = sizeof(RUNTIME_FUNCTION);
1872   _info.unwind_info = reinterpret_cast<unw_word_t>(unwindEntry);
1873   _info.extra = base;
1874   _info.start_ip = base + unwindEntry->BeginAddress;
1875 #ifdef _LIBUNWIND_TARGET_X86_64
1876   _info.end_ip = base + unwindEntry->EndAddress;
1877   // Only fill in the handler and LSDA if they're stale.
1878   if (pc != getLastPC()) {
1879     UNWIND_INFO *xdata = reinterpret_cast<UNWIND_INFO *>(base + unwindEntry->UnwindData);
1880     if (xdata->Flags & (UNW_FLAG_EHANDLER|UNW_FLAG_UHANDLER)) {
1881       // The personality is given in the UNWIND_INFO itself. The LSDA immediately
1882       // follows the UNWIND_INFO. (This follows how both Clang and MSVC emit
1883       // these structures.)
1884       // N.B. UNWIND_INFO structs are DWORD-aligned.
1885       uint32_t lastcode = (xdata->CountOfCodes + 1) & ~1;
1886       const uint32_t *handler = reinterpret_cast<uint32_t *>(&xdata->UnwindCodes[lastcode]);
1887       _info.lsda = reinterpret_cast<unw_word_t>(handler+1);
1888       if (*handler) {
1889         _info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
1890       } else
1891         _info.handler = 0;
1892     } else {
1893       _info.lsda = 0;
1894       _info.handler = 0;
1895     }
1896   }
1897 #elif defined(_LIBUNWIND_TARGET_ARM)
1898   _info.end_ip = _info.start_ip + unwindEntry->FunctionLength;
1899   _info.lsda = 0; // FIXME
1900   _info.handler = 0; // FIXME
1901 #endif
1902   setLastPC(pc);
1903   return true;
1904 }
1905 #endif
1906 
1907 
1908 template <typename A, typename R>
setInfoBasedOnIPRegister(bool isReturnAddress)1909 void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
1910 #if defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
1911   _isSigReturn = false;
1912 #endif
1913 
1914   pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
1915 #if defined(_LIBUNWIND_ARM_EHABI)
1916   // Remove the thumb bit so the IP represents the actual instruction address.
1917   // This matches the behaviour of _Unwind_GetIP on arm.
1918   pc &= (pint_t)~0x1;
1919 #endif
1920 
1921   // Exit early if at the top of the stack.
1922   if (pc == 0) {
1923     _unwindInfoMissing = true;
1924     return;
1925   }
1926 
1927   // If the last line of a function is a "throw" the compiler sometimes
1928   // emits no instructions after the call to __cxa_throw.  This means
1929   // the return address is actually the start of the next function.
1930   // To disambiguate this, back up the pc when we know it is a return
1931   // address.
1932   if (isReturnAddress)
1933     --pc;
1934 
1935   // Ask address space object to find unwind sections for this pc.
1936   UnwindInfoSections sects;
1937   if (_addressSpace.findUnwindSections(pc, sects)) {
1938 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1939     // If there is a compact unwind encoding table, look there first.
1940     if (sects.compact_unwind_section != 0) {
1941       if (this->getInfoFromCompactEncodingSection(pc, sects)) {
1942   #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1943         // Found info in table, done unless encoding says to use dwarf.
1944         uint32_t dwarfOffset;
1945         if ((sects.dwarf_section != 0) && compactSaysUseDwarf(&dwarfOffset)) {
1946           if (this->getInfoFromDwarfSection(pc, sects, dwarfOffset)) {
1947             // found info in dwarf, done
1948             return;
1949           }
1950         }
1951   #endif
1952         // If unwind table has entry, but entry says there is no unwind info,
1953         // record that we have no unwind info.
1954         if (_info.format == 0)
1955           _unwindInfoMissing = true;
1956         return;
1957       }
1958     }
1959 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1960 
1961 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1962     // If there is SEH unwind info, look there next.
1963     if (this->getInfoFromSEH(pc))
1964       return;
1965 #endif
1966 
1967 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1968     // If there is dwarf unwind info, look there next.
1969     if (sects.dwarf_section != 0) {
1970       if (this->getInfoFromDwarfSection(pc, sects)) {
1971         // found info in dwarf, done
1972         return;
1973       }
1974     }
1975 #endif
1976 
1977 #if defined(_LIBUNWIND_ARM_EHABI)
1978     // If there is ARM EHABI unwind info, look there next.
1979     if (sects.arm_section != 0 && this->getInfoFromEHABISection(pc, sects))
1980       return;
1981 #endif
1982   }
1983 
1984 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1985   // There is no static unwind info for this pc. Look to see if an FDE was
1986   // dynamically registered for it.
1987   pint_t cachedFDE = DwarfFDECache<A>::findFDE(DwarfFDECache<A>::kSearchAll,
1988                                                pc);
1989   if (cachedFDE != 0) {
1990     typename CFI_Parser<A>::FDE_Info fdeInfo;
1991     typename CFI_Parser<A>::CIE_Info cieInfo;
1992     if (!CFI_Parser<A>::decodeFDE(_addressSpace, cachedFDE, &fdeInfo, &cieInfo))
1993       if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, 0))
1994         return;
1995   }
1996 
1997   // Lastly, ask AddressSpace object about platform specific ways to locate
1998   // other FDEs.
1999   pint_t fde;
2000   if (_addressSpace.findOtherFDE(pc, fde)) {
2001     typename CFI_Parser<A>::FDE_Info fdeInfo;
2002     typename CFI_Parser<A>::CIE_Info cieInfo;
2003     if (!CFI_Parser<A>::decodeFDE(_addressSpace, fde, &fdeInfo, &cieInfo)) {
2004       // Double check this FDE is for a function that includes the pc.
2005       if ((fdeInfo.pcStart <= pc) && (pc < fdeInfo.pcEnd))
2006         if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, 0))
2007           return;
2008     }
2009   }
2010 #endif // #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
2011 
2012 #if defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
2013   if (setInfoForSigReturn())
2014     return;
2015 #endif
2016 
2017   // no unwind info, flag that we can't reliably unwind
2018   _unwindInfoMissing = true;
2019 }
2020 
2021 #if defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
2022 template <typename A, typename R>
setInfoForSigReturn(Registers_arm64 &)2023 bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_arm64 &) {
2024   // Look for the sigreturn trampoline. The trampoline's body is two
2025   // specific instructions (see below). Typically the trampoline comes from the
2026   // vDSO[1] (i.e. the __kernel_rt_sigreturn function). A libc might provide its
2027   // own restorer function, though, or user-mode QEMU might write a trampoline
2028   // onto the stack.
2029   //
2030   // This special code path is a fallback that is only used if the trampoline
2031   // lacks proper (e.g. DWARF) unwind info. On AArch64, a new DWARF register
2032   // constant for the PC needs to be defined before DWARF can handle a signal
2033   // trampoline. This code may segfault if the target PC is unreadable, e.g.:
2034   //  - The PC points at a function compiled without unwind info, and which is
2035   //    part of an execute-only mapping (e.g. using -Wl,--execute-only).
2036   //  - The PC is invalid and happens to point to unreadable or unmapped memory.
2037   //
2038   // [1] https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/vdso/sigreturn.S
2039   const pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
2040   // Look for instructions: mov x8, #0x8b; svc #0x0
2041   if (_addressSpace.get32(pc) == 0xd2801168 &&
2042       _addressSpace.get32(pc + 4) == 0xd4000001) {
2043     _info = {};
2044     _isSigReturn = true;
2045     return true;
2046   }
2047   return false;
2048 }
2049 
2050 template <typename A, typename R>
stepThroughSigReturn(Registers_arm64 &)2051 int UnwindCursor<A, R>::stepThroughSigReturn(Registers_arm64 &) {
2052   // In the signal trampoline frame, sp points to an rt_sigframe[1], which is:
2053   //  - 128-byte siginfo struct
2054   //  - ucontext struct:
2055   //     - 8-byte long (uc_flags)
2056   //     - 8-byte pointer (uc_link)
2057   //     - 24-byte stack_t
2058   //     - 128-byte signal set
2059   //     - 8 bytes of padding because sigcontext has 16-byte alignment
2060   //     - sigcontext/mcontext_t
2061   // [1] https://github.com/torvalds/linux/blob/master/arch/arm64/kernel/signal.c
2062   const pint_t kOffsetSpToSigcontext = (128 + 8 + 8 + 24 + 128 + 8); // 304
2063 
2064   // Offsets from sigcontext to each register.
2065   const pint_t kOffsetGprs = 8; // offset to "__u64 regs[31]" field
2066   const pint_t kOffsetSp = 256; // offset to "__u64 sp" field
2067   const pint_t kOffsetPc = 264; // offset to "__u64 pc" field
2068 
2069   pint_t sigctx = _registers.getSP() + kOffsetSpToSigcontext;
2070 
2071   for (int i = 0; i <= 30; ++i) {
2072     uint64_t value = _addressSpace.get64(sigctx + kOffsetGprs +
2073                                          static_cast<pint_t>(i * 8));
2074     _registers.setRegister(UNW_AARCH64_X0 + i, value);
2075   }
2076   _registers.setSP(_addressSpace.get64(sigctx + kOffsetSp));
2077   _registers.setIP(_addressSpace.get64(sigctx + kOffsetPc));
2078   _isSignalFrame = true;
2079   return UNW_STEP_SUCCESS;
2080 }
2081 #endif // defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
2082 
2083 template <typename A, typename R>
step()2084 int UnwindCursor<A, R>::step() {
2085   // Bottom of stack is defined is when unwind info cannot be found.
2086   if (_unwindInfoMissing)
2087     return UNW_STEP_END;
2088 
2089   // Use unwinding info to modify register set as if function returned.
2090   int result;
2091 #if defined(_LIBUNWIND_TARGET_LINUX) && defined(_LIBUNWIND_TARGET_AARCH64)
2092   if (_isSigReturn) {
2093     result = this->stepThroughSigReturn();
2094   } else
2095 #endif
2096   {
2097 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
2098     result = this->stepWithCompactEncoding();
2099 #elif defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
2100     result = this->stepWithSEHData();
2101 #elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
2102     result = this->stepWithDwarfFDE();
2103 #elif defined(_LIBUNWIND_ARM_EHABI)
2104     result = this->stepWithEHABI();
2105 #else
2106   #error Need _LIBUNWIND_SUPPORT_COMPACT_UNWIND or \
2107               _LIBUNWIND_SUPPORT_SEH_UNWIND or \
2108               _LIBUNWIND_SUPPORT_DWARF_UNWIND or \
2109               _LIBUNWIND_ARM_EHABI
2110 #endif
2111   }
2112 
2113   // update info based on new PC
2114   if (result == UNW_STEP_SUCCESS) {
2115     this->setInfoBasedOnIPRegister(true);
2116     if (_unwindInfoMissing)
2117       return UNW_STEP_END;
2118   }
2119 
2120   return result;
2121 }
2122 
2123 template <typename A, typename R>
getInfo(unw_proc_info_t * info)2124 void UnwindCursor<A, R>::getInfo(unw_proc_info_t *info) {
2125   if (_unwindInfoMissing)
2126     memset(info, 0, sizeof(*info));
2127   else
2128     *info = _info;
2129 }
2130 
2131 template <typename A, typename R>
getFunctionName(char * buf,size_t bufLen,unw_word_t * offset)2132 bool UnwindCursor<A, R>::getFunctionName(char *buf, size_t bufLen,
2133                                                            unw_word_t *offset) {
2134   return _addressSpace.findFunctionName((pint_t)this->getReg(UNW_REG_IP),
2135                                          buf, bufLen, offset);
2136 }
2137 
2138 #if defined(_LIBUNWIND_USE_CET)
__libunwind_cet_get_registers(unw_cursor_t * cursor)2139 extern "C" void *__libunwind_cet_get_registers(unw_cursor_t *cursor) {
2140   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
2141   return co->get_registers();
2142 }
2143 #endif
2144 } // namespace libunwind
2145 
2146 #endif // __UNWINDCURSOR_HPP__
2147