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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 <stdint.h>
15 #include <stdio.h>
16 #include <stdlib.h>
17 #include <unwind.h>
18 
19 #ifdef _WIN32
20   #include <windows.h>
21   #include <ntverp.h>
22 #endif
23 #ifdef __APPLE__
24   #include <mach-o/dyld.h>
25 #endif
26 
27 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
28 // Provide a definition for the DISPATCHER_CONTEXT struct for old (Win7 and
29 // earlier) SDKs.
30 // MinGW-w64 has always provided this struct.
31   #if defined(_WIN32) && defined(_LIBUNWIND_TARGET_X86_64) && \
32       !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
33 struct _DISPATCHER_CONTEXT {
34   ULONG64 ControlPc;
35   ULONG64 ImageBase;
36   PRUNTIME_FUNCTION FunctionEntry;
37   ULONG64 EstablisherFrame;
38   ULONG64 TargetIp;
39   PCONTEXT ContextRecord;
40   PEXCEPTION_ROUTINE LanguageHandler;
41   PVOID HandlerData;
42   PUNWIND_HISTORY_TABLE HistoryTable;
43   ULONG ScopeIndex;
44   ULONG Fill0;
45 };
46   #endif
47 
48 struct UNWIND_INFO {
49   uint8_t Version : 3;
50   uint8_t Flags : 5;
51   uint8_t SizeOfProlog;
52   uint8_t CountOfCodes;
53   uint8_t FrameRegister : 4;
54   uint8_t FrameOffset : 4;
55   uint16_t UnwindCodes[2];
56 };
57 
58 extern "C" _Unwind_Reason_Code __libunwind_seh_personality(
59     int, _Unwind_Action, uint64_t, _Unwind_Exception *,
60     struct _Unwind_Context *);
61 
62 #endif
63 
64 #include "config.h"
65 
66 #include "AddressSpace.hpp"
67 #include "CompactUnwinder.hpp"
68 #include "config.h"
69 #include "DwarfInstructions.hpp"
70 #include "EHHeaderParser.hpp"
71 #include "libunwind.h"
72 #include "Registers.hpp"
73 #include "RWMutex.hpp"
74 #include "Unwind-EHABI.h"
75 
76 namespace libunwind {
77 
78 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
79 /// Cache of recently found FDEs.
80 template <typename A>
81 class _LIBUNWIND_HIDDEN DwarfFDECache {
82   typedef typename A::pint_t pint_t;
83 public:
84   static constexpr pint_t kSearchAll = static_cast<pint_t>(-1);
85   static pint_t findFDE(pint_t mh, pint_t pc);
86   static void add(pint_t mh, pint_t ip_start, pint_t ip_end, pint_t fde);
87   static void removeAllIn(pint_t mh);
88   static void iterateCacheEntries(void (*func)(unw_word_t ip_start,
89                                                unw_word_t ip_end,
90                                                unw_word_t fde, unw_word_t mh));
91 
92 private:
93 
94   struct entry {
95     pint_t mh;
96     pint_t ip_start;
97     pint_t ip_end;
98     pint_t fde;
99   };
100 
101   // These fields are all static to avoid needing an initializer.
102   // There is only one instance of this class per process.
103   static RWMutex _lock;
104 #ifdef __APPLE__
105   static void dyldUnloadHook(const struct mach_header *mh, intptr_t slide);
106   static bool _registeredForDyldUnloads;
107 #endif
108   static entry *_buffer;
109   static entry *_bufferUsed;
110   static entry *_bufferEnd;
111   static entry _initialBuffer[64];
112 };
113 
114 template <typename A>
115 typename DwarfFDECache<A>::entry *
116 DwarfFDECache<A>::_buffer = _initialBuffer;
117 
118 template <typename A>
119 typename DwarfFDECache<A>::entry *
120 DwarfFDECache<A>::_bufferUsed = _initialBuffer;
121 
122 template <typename A>
123 typename DwarfFDECache<A>::entry *
124 DwarfFDECache<A>::_bufferEnd = &_initialBuffer[64];
125 
126 template <typename A>
127 typename DwarfFDECache<A>::entry DwarfFDECache<A>::_initialBuffer[64];
128 
129 template <typename A>
130 RWMutex DwarfFDECache<A>::_lock;
131 
132 #ifdef __APPLE__
133 template <typename A>
134 bool DwarfFDECache<A>::_registeredForDyldUnloads = false;
135 #endif
136 
137 template <typename A>
findFDE(pint_t mh,pint_t pc)138 typename A::pint_t DwarfFDECache<A>::findFDE(pint_t mh, pint_t pc) {
139   pint_t result = 0;
140   _LIBUNWIND_LOG_IF_FALSE(_lock.lock_shared());
141   for (entry *p = _buffer; p < _bufferUsed; ++p) {
142     if ((mh == p->mh) || (mh == kSearchAll)) {
143       if ((p->ip_start <= pc) && (pc < p->ip_end)) {
144         result = p->fde;
145         break;
146       }
147     }
148   }
149   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock_shared());
150   return result;
151 }
152 
153 template <typename A>
add(pint_t mh,pint_t ip_start,pint_t ip_end,pint_t fde)154 void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
155                            pint_t fde) {
156 #if !defined(_LIBUNWIND_NO_HEAP)
157   _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
158   if (_bufferUsed >= _bufferEnd) {
159     size_t oldSize = (size_t)(_bufferEnd - _buffer);
160     size_t newSize = oldSize * 4;
161     // Can't use operator new (we are below it).
162     entry *newBuffer = (entry *)malloc(newSize * sizeof(entry));
163     memcpy(newBuffer, _buffer, oldSize * sizeof(entry));
164     if (_buffer != _initialBuffer)
165       free(_buffer);
166     _buffer = newBuffer;
167     _bufferUsed = &newBuffer[oldSize];
168     _bufferEnd = &newBuffer[newSize];
169   }
170   _bufferUsed->mh = mh;
171   _bufferUsed->ip_start = ip_start;
172   _bufferUsed->ip_end = ip_end;
173   _bufferUsed->fde = fde;
174   ++_bufferUsed;
175 #ifdef __APPLE__
176   if (!_registeredForDyldUnloads) {
177     _dyld_register_func_for_remove_image(&dyldUnloadHook);
178     _registeredForDyldUnloads = true;
179   }
180 #endif
181   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
182 #endif
183 }
184 
185 template <typename A>
removeAllIn(pint_t mh)186 void DwarfFDECache<A>::removeAllIn(pint_t mh) {
187   _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
188   entry *d = _buffer;
189   for (const entry *s = _buffer; s < _bufferUsed; ++s) {
190     if (s->mh != mh) {
191       if (d != s)
192         *d = *s;
193       ++d;
194     }
195   }
196   _bufferUsed = d;
197   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
198 }
199 
200 #ifdef __APPLE__
201 template <typename A>
dyldUnloadHook(const struct mach_header * mh,intptr_t)202 void DwarfFDECache<A>::dyldUnloadHook(const struct mach_header *mh, intptr_t ) {
203   removeAllIn((pint_t) mh);
204 }
205 #endif
206 
207 template <typename A>
iterateCacheEntries(void (* func)(unw_word_t ip_start,unw_word_t ip_end,unw_word_t fde,unw_word_t mh))208 void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
209     unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
210   _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
211   for (entry *p = _buffer; p < _bufferUsed; ++p) {
212     (*func)(p->ip_start, p->ip_end, p->fde, p->mh);
213   }
214   _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
215 }
216 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
217 
218 
219 #define arrayoffsetof(type, index, field) ((size_t)(&((type *)0)[index].field))
220 
221 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
222 template <typename A> class UnwindSectionHeader {
223 public:
UnwindSectionHeader(A & addressSpace,typename A::pint_t addr)224   UnwindSectionHeader(A &addressSpace, typename A::pint_t addr)
225       : _addressSpace(addressSpace), _addr(addr) {}
226 
version() const227   uint32_t version() const {
228     return _addressSpace.get32(_addr +
229                                offsetof(unwind_info_section_header, version));
230   }
commonEncodingsArraySectionOffset() const231   uint32_t commonEncodingsArraySectionOffset() const {
232     return _addressSpace.get32(_addr +
233                                offsetof(unwind_info_section_header,
234                                         commonEncodingsArraySectionOffset));
235   }
commonEncodingsArrayCount() const236   uint32_t commonEncodingsArrayCount() const {
237     return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
238                                                 commonEncodingsArrayCount));
239   }
personalityArraySectionOffset() const240   uint32_t personalityArraySectionOffset() const {
241     return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
242                                                 personalityArraySectionOffset));
243   }
personalityArrayCount() const244   uint32_t personalityArrayCount() const {
245     return _addressSpace.get32(
246         _addr + offsetof(unwind_info_section_header, personalityArrayCount));
247   }
indexSectionOffset() const248   uint32_t indexSectionOffset() const {
249     return _addressSpace.get32(
250         _addr + offsetof(unwind_info_section_header, indexSectionOffset));
251   }
indexCount() const252   uint32_t indexCount() const {
253     return _addressSpace.get32(
254         _addr + offsetof(unwind_info_section_header, indexCount));
255   }
256 
257 private:
258   A                     &_addressSpace;
259   typename A::pint_t     _addr;
260 };
261 
262 template <typename A> class UnwindSectionIndexArray {
263 public:
UnwindSectionIndexArray(A & addressSpace,typename A::pint_t addr)264   UnwindSectionIndexArray(A &addressSpace, typename A::pint_t addr)
265       : _addressSpace(addressSpace), _addr(addr) {}
266 
functionOffset(uint32_t index) const267   uint32_t functionOffset(uint32_t index) const {
268     return _addressSpace.get32(
269         _addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
270                               functionOffset));
271   }
secondLevelPagesSectionOffset(uint32_t index) const272   uint32_t secondLevelPagesSectionOffset(uint32_t index) const {
273     return _addressSpace.get32(
274         _addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
275                               secondLevelPagesSectionOffset));
276   }
lsdaIndexArraySectionOffset(uint32_t index) const277   uint32_t lsdaIndexArraySectionOffset(uint32_t index) const {
278     return _addressSpace.get32(
279         _addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
280                               lsdaIndexArraySectionOffset));
281   }
282 
283 private:
284   A                   &_addressSpace;
285   typename A::pint_t   _addr;
286 };
287 
288 template <typename A> class UnwindSectionRegularPageHeader {
289 public:
UnwindSectionRegularPageHeader(A & addressSpace,typename A::pint_t addr)290   UnwindSectionRegularPageHeader(A &addressSpace, typename A::pint_t addr)
291       : _addressSpace(addressSpace), _addr(addr) {}
292 
kind() const293   uint32_t kind() const {
294     return _addressSpace.get32(
295         _addr + offsetof(unwind_info_regular_second_level_page_header, kind));
296   }
entryPageOffset() const297   uint16_t entryPageOffset() const {
298     return _addressSpace.get16(
299         _addr + offsetof(unwind_info_regular_second_level_page_header,
300                          entryPageOffset));
301   }
entryCount() const302   uint16_t entryCount() const {
303     return _addressSpace.get16(
304         _addr +
305         offsetof(unwind_info_regular_second_level_page_header, entryCount));
306   }
307 
308 private:
309   A &_addressSpace;
310   typename A::pint_t _addr;
311 };
312 
313 template <typename A> class UnwindSectionRegularArray {
314 public:
UnwindSectionRegularArray(A & addressSpace,typename A::pint_t addr)315   UnwindSectionRegularArray(A &addressSpace, typename A::pint_t addr)
316       : _addressSpace(addressSpace), _addr(addr) {}
317 
functionOffset(uint32_t index) const318   uint32_t functionOffset(uint32_t index) const {
319     return _addressSpace.get32(
320         _addr + arrayoffsetof(unwind_info_regular_second_level_entry, index,
321                               functionOffset));
322   }
encoding(uint32_t index) const323   uint32_t encoding(uint32_t index) const {
324     return _addressSpace.get32(
325         _addr +
326         arrayoffsetof(unwind_info_regular_second_level_entry, index, encoding));
327   }
328 
329 private:
330   A &_addressSpace;
331   typename A::pint_t _addr;
332 };
333 
334 template <typename A> class UnwindSectionCompressedPageHeader {
335 public:
UnwindSectionCompressedPageHeader(A & addressSpace,typename A::pint_t addr)336   UnwindSectionCompressedPageHeader(A &addressSpace, typename A::pint_t addr)
337       : _addressSpace(addressSpace), _addr(addr) {}
338 
kind() const339   uint32_t kind() const {
340     return _addressSpace.get32(
341         _addr +
342         offsetof(unwind_info_compressed_second_level_page_header, kind));
343   }
entryPageOffset() const344   uint16_t entryPageOffset() const {
345     return _addressSpace.get16(
346         _addr + offsetof(unwind_info_compressed_second_level_page_header,
347                          entryPageOffset));
348   }
entryCount() const349   uint16_t entryCount() const {
350     return _addressSpace.get16(
351         _addr +
352         offsetof(unwind_info_compressed_second_level_page_header, entryCount));
353   }
encodingsPageOffset() const354   uint16_t encodingsPageOffset() const {
355     return _addressSpace.get16(
356         _addr + offsetof(unwind_info_compressed_second_level_page_header,
357                          encodingsPageOffset));
358   }
encodingsCount() const359   uint16_t encodingsCount() const {
360     return _addressSpace.get16(
361         _addr + offsetof(unwind_info_compressed_second_level_page_header,
362                          encodingsCount));
363   }
364 
365 private:
366   A &_addressSpace;
367   typename A::pint_t _addr;
368 };
369 
370 template <typename A> class UnwindSectionCompressedArray {
371 public:
UnwindSectionCompressedArray(A & addressSpace,typename A::pint_t addr)372   UnwindSectionCompressedArray(A &addressSpace, typename A::pint_t addr)
373       : _addressSpace(addressSpace), _addr(addr) {}
374 
functionOffset(uint32_t index) const375   uint32_t functionOffset(uint32_t index) const {
376     return UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(
377         _addressSpace.get32(_addr + index * sizeof(uint32_t)));
378   }
encodingIndex(uint32_t index) const379   uint16_t encodingIndex(uint32_t index) const {
380     return UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(
381         _addressSpace.get32(_addr + index * sizeof(uint32_t)));
382   }
383 
384 private:
385   A &_addressSpace;
386   typename A::pint_t _addr;
387 };
388 
389 template <typename A> class UnwindSectionLsdaArray {
390 public:
UnwindSectionLsdaArray(A & addressSpace,typename A::pint_t addr)391   UnwindSectionLsdaArray(A &addressSpace, typename A::pint_t addr)
392       : _addressSpace(addressSpace), _addr(addr) {}
393 
functionOffset(uint32_t index) const394   uint32_t functionOffset(uint32_t index) const {
395     return _addressSpace.get32(
396         _addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
397                               index, functionOffset));
398   }
lsdaOffset(uint32_t index) const399   uint32_t lsdaOffset(uint32_t index) const {
400     return _addressSpace.get32(
401         _addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
402                               index, lsdaOffset));
403   }
404 
405 private:
406   A                   &_addressSpace;
407   typename A::pint_t   _addr;
408 };
409 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
410 
411 class _LIBUNWIND_HIDDEN AbstractUnwindCursor {
412 public:
413   // NOTE: provide a class specific placement deallocation function (S5.3.4 p20)
414   // This avoids an unnecessary dependency to libc++abi.
operator delete(void *,size_t)415   void operator delete(void *, size_t) {}
416 
~AbstractUnwindCursor()417   virtual ~AbstractUnwindCursor() {}
validReg(int)418   virtual bool validReg(int) { _LIBUNWIND_ABORT("validReg not implemented"); }
getReg(int)419   virtual unw_word_t getReg(int) { _LIBUNWIND_ABORT("getReg not implemented"); }
setReg(int,unw_word_t)420   virtual void setReg(int, unw_word_t) {
421     _LIBUNWIND_ABORT("setReg not implemented");
422   }
validFloatReg(int)423   virtual bool validFloatReg(int) {
424     _LIBUNWIND_ABORT("validFloatReg not implemented");
425   }
getFloatReg(int)426   virtual unw_fpreg_t getFloatReg(int) {
427     _LIBUNWIND_ABORT("getFloatReg not implemented");
428   }
setFloatReg(int,unw_fpreg_t)429   virtual void setFloatReg(int, unw_fpreg_t) {
430     _LIBUNWIND_ABORT("setFloatReg not implemented");
431   }
step()432   virtual int step() { _LIBUNWIND_ABORT("step not implemented"); }
getInfo(unw_proc_info_t *)433   virtual void getInfo(unw_proc_info_t *) {
434     _LIBUNWIND_ABORT("getInfo not implemented");
435   }
jumpto()436   virtual void jumpto() { _LIBUNWIND_ABORT("jumpto not implemented"); }
isSignalFrame()437   virtual bool isSignalFrame() {
438     _LIBUNWIND_ABORT("isSignalFrame not implemented");
439   }
getFunctionName(char *,size_t,unw_word_t *)440   virtual bool getFunctionName(char *, size_t, unw_word_t *) {
441     _LIBUNWIND_ABORT("getFunctionName not implemented");
442   }
setInfoBasedOnIPRegister(bool=false)443   virtual void setInfoBasedOnIPRegister(bool = false) {
444     _LIBUNWIND_ABORT("setInfoBasedOnIPRegister not implemented");
445   }
getRegisterName(int)446   virtual const char *getRegisterName(int) {
447     _LIBUNWIND_ABORT("getRegisterName not implemented");
448   }
449 #ifdef __arm__
saveVFPAsX()450   virtual void saveVFPAsX() { _LIBUNWIND_ABORT("saveVFPAsX not implemented"); }
451 #endif
452 };
453 
454 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)
455 
456 /// \c UnwindCursor contains all state (including all register values) during
457 /// an unwind.  This is normally stack-allocated inside a unw_cursor_t.
458 template <typename A, typename R>
459 class UnwindCursor : public AbstractUnwindCursor {
460   typedef typename A::pint_t pint_t;
461 public:
462                       UnwindCursor(unw_context_t *context, A &as);
463                       UnwindCursor(CONTEXT *context, A &as);
464                       UnwindCursor(A &as, void *threadArg);
~UnwindCursor()465   virtual             ~UnwindCursor() {}
466   virtual bool        validReg(int);
467   virtual unw_word_t  getReg(int);
468   virtual void        setReg(int, unw_word_t);
469   virtual bool        validFloatReg(int);
470   virtual unw_fpreg_t getFloatReg(int);
471   virtual void        setFloatReg(int, unw_fpreg_t);
472   virtual int         step();
473   virtual void        getInfo(unw_proc_info_t *);
474   virtual void        jumpto();
475   virtual bool        isSignalFrame();
476   virtual bool        getFunctionName(char *buf, size_t len, unw_word_t *off);
477   virtual void        setInfoBasedOnIPRegister(bool isReturnAddress = false);
478   virtual const char *getRegisterName(int num);
479 #ifdef __arm__
480   virtual void        saveVFPAsX();
481 #endif
482 
getDispatcherContext()483   DISPATCHER_CONTEXT *getDispatcherContext() { return &_dispContext; }
setDispatcherContext(DISPATCHER_CONTEXT * disp)484   void setDispatcherContext(DISPATCHER_CONTEXT *disp) { _dispContext = *disp; }
485 
486   // libunwind does not and should not depend on C++ library which means that we
487   // need our own defition of inline placement new.
operator new(size_t,UnwindCursor<A,R> * p)488   static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
489 
490 private:
491 
getLastPC() const492   pint_t getLastPC() const { return _dispContext.ControlPc; }
setLastPC(pint_t pc)493   void setLastPC(pint_t pc) { _dispContext.ControlPc = pc; }
lookUpSEHUnwindInfo(pint_t pc,pint_t * base)494   RUNTIME_FUNCTION *lookUpSEHUnwindInfo(pint_t pc, pint_t *base) {
495     _dispContext.FunctionEntry = RtlLookupFunctionEntry(pc,
496                                                         &_dispContext.ImageBase,
497                                                         _dispContext.HistoryTable);
498     *base = _dispContext.ImageBase;
499     return _dispContext.FunctionEntry;
500   }
501   bool getInfoFromSEH(pint_t pc);
stepWithSEHData()502   int stepWithSEHData() {
503     _dispContext.LanguageHandler = RtlVirtualUnwind(UNW_FLAG_UHANDLER,
504                                                     _dispContext.ImageBase,
505                                                     _dispContext.ControlPc,
506                                                     _dispContext.FunctionEntry,
507                                                     _dispContext.ContextRecord,
508                                                     &_dispContext.HandlerData,
509                                                     &_dispContext.EstablisherFrame,
510                                                     NULL);
511     // Update some fields of the unwind info now, since we have them.
512     _info.lsda = reinterpret_cast<unw_word_t>(_dispContext.HandlerData);
513     if (_dispContext.LanguageHandler) {
514       _info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
515     } else
516       _info.handler = 0;
517     return UNW_STEP_SUCCESS;
518   }
519 
520   A                   &_addressSpace;
521   unw_proc_info_t      _info;
522   DISPATCHER_CONTEXT   _dispContext;
523   CONTEXT              _msContext;
524   UNWIND_HISTORY_TABLE _histTable;
525   bool                 _unwindInfoMissing;
526 };
527 
528 
529 template <typename A, typename R>
UnwindCursor(unw_context_t * context,A & as)530 UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
531     : _addressSpace(as), _unwindInfoMissing(false) {
532   static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
533                 "UnwindCursor<> does not fit in unw_cursor_t");
534   static_assert((alignof(UnwindCursor<A, R>) <= alignof(unw_cursor_t)),
535                 "UnwindCursor<> requires more alignment than unw_cursor_t");
536   memset(&_info, 0, sizeof(_info));
537   memset(&_histTable, 0, sizeof(_histTable));
538   _dispContext.ContextRecord = &_msContext;
539   _dispContext.HistoryTable = &_histTable;
540   // Initialize MS context from ours.
541   R r(context);
542   _msContext.ContextFlags = CONTEXT_CONTROL|CONTEXT_INTEGER|CONTEXT_FLOATING_POINT;
543 #if defined(_LIBUNWIND_TARGET_X86_64)
544   _msContext.Rax = r.getRegister(UNW_X86_64_RAX);
545   _msContext.Rcx = r.getRegister(UNW_X86_64_RCX);
546   _msContext.Rdx = r.getRegister(UNW_X86_64_RDX);
547   _msContext.Rbx = r.getRegister(UNW_X86_64_RBX);
548   _msContext.Rsp = r.getRegister(UNW_X86_64_RSP);
549   _msContext.Rbp = r.getRegister(UNW_X86_64_RBP);
550   _msContext.Rsi = r.getRegister(UNW_X86_64_RSI);
551   _msContext.Rdi = r.getRegister(UNW_X86_64_RDI);
552   _msContext.R8 = r.getRegister(UNW_X86_64_R8);
553   _msContext.R9 = r.getRegister(UNW_X86_64_R9);
554   _msContext.R10 = r.getRegister(UNW_X86_64_R10);
555   _msContext.R11 = r.getRegister(UNW_X86_64_R11);
556   _msContext.R12 = r.getRegister(UNW_X86_64_R12);
557   _msContext.R13 = r.getRegister(UNW_X86_64_R13);
558   _msContext.R14 = r.getRegister(UNW_X86_64_R14);
559   _msContext.R15 = r.getRegister(UNW_X86_64_R15);
560   _msContext.Rip = r.getRegister(UNW_REG_IP);
561   union {
562     v128 v;
563     M128A m;
564   } t;
565   t.v = r.getVectorRegister(UNW_X86_64_XMM0);
566   _msContext.Xmm0 = t.m;
567   t.v = r.getVectorRegister(UNW_X86_64_XMM1);
568   _msContext.Xmm1 = t.m;
569   t.v = r.getVectorRegister(UNW_X86_64_XMM2);
570   _msContext.Xmm2 = t.m;
571   t.v = r.getVectorRegister(UNW_X86_64_XMM3);
572   _msContext.Xmm3 = t.m;
573   t.v = r.getVectorRegister(UNW_X86_64_XMM4);
574   _msContext.Xmm4 = t.m;
575   t.v = r.getVectorRegister(UNW_X86_64_XMM5);
576   _msContext.Xmm5 = t.m;
577   t.v = r.getVectorRegister(UNW_X86_64_XMM6);
578   _msContext.Xmm6 = t.m;
579   t.v = r.getVectorRegister(UNW_X86_64_XMM7);
580   _msContext.Xmm7 = t.m;
581   t.v = r.getVectorRegister(UNW_X86_64_XMM8);
582   _msContext.Xmm8 = t.m;
583   t.v = r.getVectorRegister(UNW_X86_64_XMM9);
584   _msContext.Xmm9 = t.m;
585   t.v = r.getVectorRegister(UNW_X86_64_XMM10);
586   _msContext.Xmm10 = t.m;
587   t.v = r.getVectorRegister(UNW_X86_64_XMM11);
588   _msContext.Xmm11 = t.m;
589   t.v = r.getVectorRegister(UNW_X86_64_XMM12);
590   _msContext.Xmm12 = t.m;
591   t.v = r.getVectorRegister(UNW_X86_64_XMM13);
592   _msContext.Xmm13 = t.m;
593   t.v = r.getVectorRegister(UNW_X86_64_XMM14);
594   _msContext.Xmm14 = t.m;
595   t.v = r.getVectorRegister(UNW_X86_64_XMM15);
596   _msContext.Xmm15 = t.m;
597 #elif defined(_LIBUNWIND_TARGET_ARM)
598   _msContext.R0 = r.getRegister(UNW_ARM_R0);
599   _msContext.R1 = r.getRegister(UNW_ARM_R1);
600   _msContext.R2 = r.getRegister(UNW_ARM_R2);
601   _msContext.R3 = r.getRegister(UNW_ARM_R3);
602   _msContext.R4 = r.getRegister(UNW_ARM_R4);
603   _msContext.R5 = r.getRegister(UNW_ARM_R5);
604   _msContext.R6 = r.getRegister(UNW_ARM_R6);
605   _msContext.R7 = r.getRegister(UNW_ARM_R7);
606   _msContext.R8 = r.getRegister(UNW_ARM_R8);
607   _msContext.R9 = r.getRegister(UNW_ARM_R9);
608   _msContext.R10 = r.getRegister(UNW_ARM_R10);
609   _msContext.R11 = r.getRegister(UNW_ARM_R11);
610   _msContext.R12 = r.getRegister(UNW_ARM_R12);
611   _msContext.Sp = r.getRegister(UNW_ARM_SP);
612   _msContext.Lr = r.getRegister(UNW_ARM_LR);
613   _msContext.Pc = r.getRegister(UNW_ARM_IP);
614   for (int i = UNW_ARM_D0; i <= UNW_ARM_D31; ++i) {
615     union {
616       uint64_t w;
617       double d;
618     } d;
619     d.d = r.getFloatRegister(i);
620     _msContext.D[i - UNW_ARM_D0] = d.w;
621   }
622 #elif defined(_LIBUNWIND_TARGET_AARCH64)
623   for (int i = UNW_ARM64_X0; i <= UNW_ARM64_X30; ++i)
624     _msContext.X[i - UNW_ARM64_X0] = r.getRegister(i);
625   _msContext.Sp = r.getRegister(UNW_REG_SP);
626   _msContext.Pc = r.getRegister(UNW_REG_IP);
627   for (int i = UNW_ARM64_D0; i <= UNW_ARM64_D31; ++i)
628     _msContext.V[i - UNW_ARM64_D0].D[0] = r.getFloatRegister(i);
629 #endif
630 }
631 
632 template <typename A, typename R>
UnwindCursor(CONTEXT * context,A & as)633 UnwindCursor<A, R>::UnwindCursor(CONTEXT *context, A &as)
634     : _addressSpace(as), _unwindInfoMissing(false) {
635   static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
636                 "UnwindCursor<> does not fit in unw_cursor_t");
637   memset(&_info, 0, sizeof(_info));
638   memset(&_histTable, 0, sizeof(_histTable));
639   _dispContext.ContextRecord = &_msContext;
640   _dispContext.HistoryTable = &_histTable;
641   _msContext = *context;
642 }
643 
644 
645 template <typename A, typename R>
validReg(int regNum)646 bool UnwindCursor<A, R>::validReg(int regNum) {
647   if (regNum == UNW_REG_IP || regNum == UNW_REG_SP) return true;
648 #if defined(_LIBUNWIND_TARGET_X86_64)
649   if (regNum >= UNW_X86_64_RAX && regNum <= UNW_X86_64_R15) return true;
650 #elif defined(_LIBUNWIND_TARGET_ARM)
651   if (regNum >= UNW_ARM_R0 && regNum <= UNW_ARM_R15) return true;
652 #elif defined(_LIBUNWIND_TARGET_AARCH64)
653   if (regNum >= UNW_ARM64_X0 && regNum <= UNW_ARM64_X30) return true;
654 #endif
655   return false;
656 }
657 
658 template <typename A, typename R>
getReg(int regNum)659 unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
660   switch (regNum) {
661 #if defined(_LIBUNWIND_TARGET_X86_64)
662   case UNW_REG_IP: return _msContext.Rip;
663   case UNW_X86_64_RAX: return _msContext.Rax;
664   case UNW_X86_64_RDX: return _msContext.Rdx;
665   case UNW_X86_64_RCX: return _msContext.Rcx;
666   case UNW_X86_64_RBX: return _msContext.Rbx;
667   case UNW_REG_SP:
668   case UNW_X86_64_RSP: return _msContext.Rsp;
669   case UNW_X86_64_RBP: return _msContext.Rbp;
670   case UNW_X86_64_RSI: return _msContext.Rsi;
671   case UNW_X86_64_RDI: return _msContext.Rdi;
672   case UNW_X86_64_R8: return _msContext.R8;
673   case UNW_X86_64_R9: return _msContext.R9;
674   case UNW_X86_64_R10: return _msContext.R10;
675   case UNW_X86_64_R11: return _msContext.R11;
676   case UNW_X86_64_R12: return _msContext.R12;
677   case UNW_X86_64_R13: return _msContext.R13;
678   case UNW_X86_64_R14: return _msContext.R14;
679   case UNW_X86_64_R15: return _msContext.R15;
680 #elif defined(_LIBUNWIND_TARGET_ARM)
681   case UNW_ARM_R0: return _msContext.R0;
682   case UNW_ARM_R1: return _msContext.R1;
683   case UNW_ARM_R2: return _msContext.R2;
684   case UNW_ARM_R3: return _msContext.R3;
685   case UNW_ARM_R4: return _msContext.R4;
686   case UNW_ARM_R5: return _msContext.R5;
687   case UNW_ARM_R6: return _msContext.R6;
688   case UNW_ARM_R7: return _msContext.R7;
689   case UNW_ARM_R8: return _msContext.R8;
690   case UNW_ARM_R9: return _msContext.R9;
691   case UNW_ARM_R10: return _msContext.R10;
692   case UNW_ARM_R11: return _msContext.R11;
693   case UNW_ARM_R12: return _msContext.R12;
694   case UNW_REG_SP:
695   case UNW_ARM_SP: return _msContext.Sp;
696   case UNW_ARM_LR: return _msContext.Lr;
697   case UNW_REG_IP:
698   case UNW_ARM_IP: return _msContext.Pc;
699 #elif defined(_LIBUNWIND_TARGET_AARCH64)
700   case UNW_REG_SP: return _msContext.Sp;
701   case UNW_REG_IP: return _msContext.Pc;
702   default: return _msContext.X[regNum - UNW_ARM64_X0];
703 #endif
704   }
705   _LIBUNWIND_ABORT("unsupported register");
706 }
707 
708 template <typename A, typename R>
setReg(int regNum,unw_word_t value)709 void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
710   switch (regNum) {
711 #if defined(_LIBUNWIND_TARGET_X86_64)
712   case UNW_REG_IP: _msContext.Rip = value; break;
713   case UNW_X86_64_RAX: _msContext.Rax = value; break;
714   case UNW_X86_64_RDX: _msContext.Rdx = value; break;
715   case UNW_X86_64_RCX: _msContext.Rcx = value; break;
716   case UNW_X86_64_RBX: _msContext.Rbx = value; break;
717   case UNW_REG_SP:
718   case UNW_X86_64_RSP: _msContext.Rsp = value; break;
719   case UNW_X86_64_RBP: _msContext.Rbp = value; break;
720   case UNW_X86_64_RSI: _msContext.Rsi = value; break;
721   case UNW_X86_64_RDI: _msContext.Rdi = value; break;
722   case UNW_X86_64_R8: _msContext.R8 = value; break;
723   case UNW_X86_64_R9: _msContext.R9 = value; break;
724   case UNW_X86_64_R10: _msContext.R10 = value; break;
725   case UNW_X86_64_R11: _msContext.R11 = value; break;
726   case UNW_X86_64_R12: _msContext.R12 = value; break;
727   case UNW_X86_64_R13: _msContext.R13 = value; break;
728   case UNW_X86_64_R14: _msContext.R14 = value; break;
729   case UNW_X86_64_R15: _msContext.R15 = value; break;
730 #elif defined(_LIBUNWIND_TARGET_ARM)
731   case UNW_ARM_R0: _msContext.R0 = value; break;
732   case UNW_ARM_R1: _msContext.R1 = value; break;
733   case UNW_ARM_R2: _msContext.R2 = value; break;
734   case UNW_ARM_R3: _msContext.R3 = value; break;
735   case UNW_ARM_R4: _msContext.R4 = value; break;
736   case UNW_ARM_R5: _msContext.R5 = value; break;
737   case UNW_ARM_R6: _msContext.R6 = value; break;
738   case UNW_ARM_R7: _msContext.R7 = value; break;
739   case UNW_ARM_R8: _msContext.R8 = value; break;
740   case UNW_ARM_R9: _msContext.R9 = value; break;
741   case UNW_ARM_R10: _msContext.R10 = value; break;
742   case UNW_ARM_R11: _msContext.R11 = value; break;
743   case UNW_ARM_R12: _msContext.R12 = value; break;
744   case UNW_REG_SP:
745   case UNW_ARM_SP: _msContext.Sp = value; break;
746   case UNW_ARM_LR: _msContext.Lr = value; break;
747   case UNW_REG_IP:
748   case UNW_ARM_IP: _msContext.Pc = value; break;
749 #elif defined(_LIBUNWIND_TARGET_AARCH64)
750   case UNW_REG_SP: _msContext.Sp = value; break;
751   case UNW_REG_IP: _msContext.Pc = value; break;
752   case UNW_ARM64_X0:
753   case UNW_ARM64_X1:
754   case UNW_ARM64_X2:
755   case UNW_ARM64_X3:
756   case UNW_ARM64_X4:
757   case UNW_ARM64_X5:
758   case UNW_ARM64_X6:
759   case UNW_ARM64_X7:
760   case UNW_ARM64_X8:
761   case UNW_ARM64_X9:
762   case UNW_ARM64_X10:
763   case UNW_ARM64_X11:
764   case UNW_ARM64_X12:
765   case UNW_ARM64_X13:
766   case UNW_ARM64_X14:
767   case UNW_ARM64_X15:
768   case UNW_ARM64_X16:
769   case UNW_ARM64_X17:
770   case UNW_ARM64_X18:
771   case UNW_ARM64_X19:
772   case UNW_ARM64_X20:
773   case UNW_ARM64_X21:
774   case UNW_ARM64_X22:
775   case UNW_ARM64_X23:
776   case UNW_ARM64_X24:
777   case UNW_ARM64_X25:
778   case UNW_ARM64_X26:
779   case UNW_ARM64_X27:
780   case UNW_ARM64_X28:
781   case UNW_ARM64_FP:
782   case UNW_ARM64_LR: _msContext.X[regNum - UNW_ARM64_X0] = value; break;
783 #endif
784   default:
785     _LIBUNWIND_ABORT("unsupported register");
786   }
787 }
788 
789 template <typename A, typename R>
validFloatReg(int regNum)790 bool UnwindCursor<A, R>::validFloatReg(int regNum) {
791 #if defined(_LIBUNWIND_TARGET_ARM)
792   if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) return true;
793   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) return true;
794 #elif defined(_LIBUNWIND_TARGET_AARCH64)
795   if (regNum >= UNW_ARM64_D0 && regNum <= UNW_ARM64_D31) return true;
796 #else
797   (void)regNum;
798 #endif
799   return false;
800 }
801 
802 template <typename A, typename R>
getFloatReg(int regNum)803 unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
804 #if defined(_LIBUNWIND_TARGET_ARM)
805   if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) {
806     union {
807       uint32_t w;
808       float f;
809     } d;
810     d.w = _msContext.S[regNum - UNW_ARM_S0];
811     return d.f;
812   }
813   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {
814     union {
815       uint64_t w;
816       double d;
817     } d;
818     d.w = _msContext.D[regNum - UNW_ARM_D0];
819     return d.d;
820   }
821   _LIBUNWIND_ABORT("unsupported float register");
822 #elif defined(_LIBUNWIND_TARGET_AARCH64)
823   return _msContext.V[regNum - UNW_ARM64_D0].D[0];
824 #else
825   (void)regNum;
826   _LIBUNWIND_ABORT("float registers unimplemented");
827 #endif
828 }
829 
830 template <typename A, typename R>
setFloatReg(int regNum,unw_fpreg_t value)831 void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
832 #if defined(_LIBUNWIND_TARGET_ARM)
833   if (regNum >= UNW_ARM_S0 && regNum <= UNW_ARM_S31) {
834     union {
835       uint32_t w;
836       float f;
837     } d;
838     d.f = value;
839     _msContext.S[regNum - UNW_ARM_S0] = d.w;
840   }
841   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {
842     union {
843       uint64_t w;
844       double d;
845     } d;
846     d.d = value;
847     _msContext.D[regNum - UNW_ARM_D0] = d.w;
848   }
849   _LIBUNWIND_ABORT("unsupported float register");
850 #elif defined(_LIBUNWIND_TARGET_AARCH64)
851   _msContext.V[regNum - UNW_ARM64_D0].D[0] = value;
852 #else
853   (void)regNum;
854   (void)value;
855   _LIBUNWIND_ABORT("float registers unimplemented");
856 #endif
857 }
858 
jumpto()859 template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
860   RtlRestoreContext(&_msContext, nullptr);
861 }
862 
863 #ifdef __arm__
saveVFPAsX()864 template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {}
865 #endif
866 
867 template <typename A, typename R>
getRegisterName(int regNum)868 const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
869   return R::getRegisterName(regNum);
870 }
871 
isSignalFrame()872 template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
873   return false;
874 }
875 
876 #else  // !defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) || !defined(_WIN32)
877 
878 /// UnwindCursor contains all state (including all register values) during
879 /// an unwind.  This is normally stack allocated inside a unw_cursor_t.
880 template <typename A, typename R>
881 class UnwindCursor : public AbstractUnwindCursor{
882   typedef typename A::pint_t pint_t;
883 public:
884                       UnwindCursor(unw_context_t *context, A &as);
885                       UnwindCursor(A &as, void *threadArg);
~UnwindCursor()886   virtual             ~UnwindCursor() {}
887   virtual bool        validReg(int);
888   virtual unw_word_t  getReg(int);
889   virtual void        setReg(int, unw_word_t);
890   virtual bool        validFloatReg(int);
891   virtual unw_fpreg_t getFloatReg(int);
892   virtual void        setFloatReg(int, unw_fpreg_t);
893   virtual int         step();
894   virtual void        getInfo(unw_proc_info_t *);
895   virtual void        jumpto();
896   virtual bool        isSignalFrame();
897   virtual bool        getFunctionName(char *buf, size_t len, unw_word_t *off);
898   virtual void        setInfoBasedOnIPRegister(bool isReturnAddress = false);
899   virtual const char *getRegisterName(int num);
900 #ifdef __arm__
901   virtual void        saveVFPAsX();
902 #endif
903 
904   // libunwind does not and should not depend on C++ library which means that we
905   // need our own defition of inline placement new.
operator new(size_t,UnwindCursor<A,R> * p)906   static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
907 
908 private:
909 
910 #if defined(_LIBUNWIND_ARM_EHABI)
911   bool getInfoFromEHABISection(pint_t pc, const UnwindInfoSections &sects);
912 
stepWithEHABI()913   int stepWithEHABI() {
914     size_t len = 0;
915     size_t off = 0;
916     // FIXME: Calling decode_eht_entry() here is violating the libunwind
917     // abstraction layer.
918     const uint32_t *ehtp =
919         decode_eht_entry(reinterpret_cast<const uint32_t *>(_info.unwind_info),
920                          &off, &len);
921     if (_Unwind_VRS_Interpret((_Unwind_Context *)this, ehtp, off, len) !=
922             _URC_CONTINUE_UNWIND)
923       return UNW_STEP_END;
924     return UNW_STEP_SUCCESS;
925   }
926 #endif
927 
928 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
929   bool getInfoFromFdeCie(const typename CFI_Parser<A>::FDE_Info &fdeInfo,
930                          const typename CFI_Parser<A>::CIE_Info &cieInfo,
931                          pint_t pc, uintptr_t dso_base);
932   bool getInfoFromDwarfSection(pint_t pc, const UnwindInfoSections &sects,
933                                             uint32_t fdeSectionOffsetHint=0);
stepWithDwarfFDE()934   int stepWithDwarfFDE() {
935     return DwarfInstructions<A, R>::stepWithDwarf(_addressSpace,
936                                               (pint_t)this->getReg(UNW_REG_IP),
937                                               (pint_t)_info.unwind_info,
938                                               _registers, _isSignalFrame);
939   }
940 #endif
941 
942 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
943   bool getInfoFromCompactEncodingSection(pint_t pc,
944                                             const UnwindInfoSections &sects);
stepWithCompactEncoding()945   int stepWithCompactEncoding() {
946   #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
947     if ( compactSaysUseDwarf() )
948       return stepWithDwarfFDE();
949   #endif
950     R dummy;
951     return stepWithCompactEncoding(dummy);
952   }
953 
954 #if defined(_LIBUNWIND_TARGET_X86_64)
stepWithCompactEncoding(Registers_x86_64 &)955   int stepWithCompactEncoding(Registers_x86_64 &) {
956     return CompactUnwinder_x86_64<A>::stepWithCompactEncoding(
957         _info.format, _info.start_ip, _addressSpace, _registers);
958   }
959 #endif
960 
961 #if defined(_LIBUNWIND_TARGET_I386)
stepWithCompactEncoding(Registers_x86 &)962   int stepWithCompactEncoding(Registers_x86 &) {
963     return CompactUnwinder_x86<A>::stepWithCompactEncoding(
964         _info.format, (uint32_t)_info.start_ip, _addressSpace, _registers);
965   }
966 #endif
967 
968 #if defined(_LIBUNWIND_TARGET_PPC)
stepWithCompactEncoding(Registers_ppc &)969   int stepWithCompactEncoding(Registers_ppc &) {
970     return UNW_EINVAL;
971   }
972 #endif
973 
974 #if defined(_LIBUNWIND_TARGET_PPC64)
stepWithCompactEncoding(Registers_ppc64 &)975   int stepWithCompactEncoding(Registers_ppc64 &) {
976     return UNW_EINVAL;
977   }
978 #endif
979 
980 
981 #if defined(_LIBUNWIND_TARGET_AARCH64)
stepWithCompactEncoding(Registers_arm64 &)982   int stepWithCompactEncoding(Registers_arm64 &) {
983     return CompactUnwinder_arm64<A>::stepWithCompactEncoding(
984         _info.format, _info.start_ip, _addressSpace, _registers);
985   }
986 #endif
987 
988 #if defined(_LIBUNWIND_TARGET_MIPS_O32)
stepWithCompactEncoding(Registers_mips_o32 &)989   int stepWithCompactEncoding(Registers_mips_o32 &) {
990     return UNW_EINVAL;
991   }
992 #endif
993 
994 #if defined(_LIBUNWIND_TARGET_MIPS_NEWABI)
stepWithCompactEncoding(Registers_mips_newabi &)995   int stepWithCompactEncoding(Registers_mips_newabi &) {
996     return UNW_EINVAL;
997   }
998 #endif
999 
1000 #if defined(_LIBUNWIND_TARGET_SPARC)
stepWithCompactEncoding(Registers_sparc &)1001   int stepWithCompactEncoding(Registers_sparc &) { return UNW_EINVAL; }
1002 #endif
1003 
1004 #if defined (_LIBUNWIND_TARGET_RISCV)
stepWithCompactEncoding(Registers_riscv &)1005   int stepWithCompactEncoding(Registers_riscv &) {
1006     return UNW_EINVAL;
1007   }
1008 #endif
1009 
compactSaysUseDwarf(uint32_t * offset=NULL) const1010   bool compactSaysUseDwarf(uint32_t *offset=NULL) const {
1011     R dummy;
1012     return compactSaysUseDwarf(dummy, offset);
1013   }
1014 
1015 #if defined(_LIBUNWIND_TARGET_X86_64)
compactSaysUseDwarf(Registers_x86_64 &,uint32_t * offset) const1016   bool compactSaysUseDwarf(Registers_x86_64 &, uint32_t *offset) const {
1017     if ((_info.format & UNWIND_X86_64_MODE_MASK) == UNWIND_X86_64_MODE_DWARF) {
1018       if (offset)
1019         *offset = (_info.format & UNWIND_X86_64_DWARF_SECTION_OFFSET);
1020       return true;
1021     }
1022     return false;
1023   }
1024 #endif
1025 
1026 #if defined(_LIBUNWIND_TARGET_I386)
compactSaysUseDwarf(Registers_x86 &,uint32_t * offset) const1027   bool compactSaysUseDwarf(Registers_x86 &, uint32_t *offset) const {
1028     if ((_info.format & UNWIND_X86_MODE_MASK) == UNWIND_X86_MODE_DWARF) {
1029       if (offset)
1030         *offset = (_info.format & UNWIND_X86_DWARF_SECTION_OFFSET);
1031       return true;
1032     }
1033     return false;
1034   }
1035 #endif
1036 
1037 #if defined(_LIBUNWIND_TARGET_PPC)
compactSaysUseDwarf(Registers_ppc &,uint32_t *) const1038   bool compactSaysUseDwarf(Registers_ppc &, uint32_t *) const {
1039     return true;
1040   }
1041 #endif
1042 
1043 #if defined(_LIBUNWIND_TARGET_PPC64)
compactSaysUseDwarf(Registers_ppc64 &,uint32_t *) const1044   bool compactSaysUseDwarf(Registers_ppc64 &, uint32_t *) const {
1045     return true;
1046   }
1047 #endif
1048 
1049 #if defined(_LIBUNWIND_TARGET_AARCH64)
compactSaysUseDwarf(Registers_arm64 &,uint32_t * offset) const1050   bool compactSaysUseDwarf(Registers_arm64 &, uint32_t *offset) const {
1051     if ((_info.format & UNWIND_ARM64_MODE_MASK) == UNWIND_ARM64_MODE_DWARF) {
1052       if (offset)
1053         *offset = (_info.format & UNWIND_ARM64_DWARF_SECTION_OFFSET);
1054       return true;
1055     }
1056     return false;
1057   }
1058 #endif
1059 
1060 #if defined(_LIBUNWIND_TARGET_MIPS_O32)
compactSaysUseDwarf(Registers_mips_o32 &,uint32_t *) const1061   bool compactSaysUseDwarf(Registers_mips_o32 &, uint32_t *) const {
1062     return true;
1063   }
1064 #endif
1065 
1066 #if defined(_LIBUNWIND_TARGET_MIPS_NEWABI)
compactSaysUseDwarf(Registers_mips_newabi &,uint32_t *) const1067   bool compactSaysUseDwarf(Registers_mips_newabi &, uint32_t *) const {
1068     return true;
1069   }
1070 #endif
1071 
1072 #if defined(_LIBUNWIND_TARGET_SPARC)
compactSaysUseDwarf(Registers_sparc &,uint32_t *) const1073   bool compactSaysUseDwarf(Registers_sparc &, uint32_t *) const { return true; }
1074 #endif
1075 
1076 #if defined (_LIBUNWIND_TARGET_RISCV)
compactSaysUseDwarf(Registers_riscv &,uint32_t *) const1077   bool compactSaysUseDwarf(Registers_riscv &, uint32_t *) const {
1078     return true;
1079   }
1080 #endif
1081 
1082 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1083 
1084 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
dwarfEncoding() const1085   compact_unwind_encoding_t dwarfEncoding() const {
1086     R dummy;
1087     return dwarfEncoding(dummy);
1088   }
1089 
1090 #if defined(_LIBUNWIND_TARGET_X86_64)
dwarfEncoding(Registers_x86_64 &) const1091   compact_unwind_encoding_t dwarfEncoding(Registers_x86_64 &) const {
1092     return UNWIND_X86_64_MODE_DWARF;
1093   }
1094 #endif
1095 
1096 #if defined(_LIBUNWIND_TARGET_I386)
dwarfEncoding(Registers_x86 &) const1097   compact_unwind_encoding_t dwarfEncoding(Registers_x86 &) const {
1098     return UNWIND_X86_MODE_DWARF;
1099   }
1100 #endif
1101 
1102 #if defined(_LIBUNWIND_TARGET_PPC)
dwarfEncoding(Registers_ppc &) const1103   compact_unwind_encoding_t dwarfEncoding(Registers_ppc &) const {
1104     return 0;
1105   }
1106 #endif
1107 
1108 #if defined(_LIBUNWIND_TARGET_PPC64)
dwarfEncoding(Registers_ppc64 &) const1109   compact_unwind_encoding_t dwarfEncoding(Registers_ppc64 &) const {
1110     return 0;
1111   }
1112 #endif
1113 
1114 #if defined(_LIBUNWIND_TARGET_AARCH64)
dwarfEncoding(Registers_arm64 &) const1115   compact_unwind_encoding_t dwarfEncoding(Registers_arm64 &) const {
1116     return UNWIND_ARM64_MODE_DWARF;
1117   }
1118 #endif
1119 
1120 #if defined(_LIBUNWIND_TARGET_ARM)
dwarfEncoding(Registers_arm &) const1121   compact_unwind_encoding_t dwarfEncoding(Registers_arm &) const {
1122     return 0;
1123   }
1124 #endif
1125 
1126 #if defined (_LIBUNWIND_TARGET_OR1K)
dwarfEncoding(Registers_or1k &) const1127   compact_unwind_encoding_t dwarfEncoding(Registers_or1k &) const {
1128     return 0;
1129   }
1130 #endif
1131 
1132 #if defined (_LIBUNWIND_TARGET_HEXAGON)
dwarfEncoding(Registers_hexagon &) const1133   compact_unwind_encoding_t dwarfEncoding(Registers_hexagon &) const {
1134     return 0;
1135   }
1136 #endif
1137 
1138 #if defined (_LIBUNWIND_TARGET_MIPS_O32)
dwarfEncoding(Registers_mips_o32 &) const1139   compact_unwind_encoding_t dwarfEncoding(Registers_mips_o32 &) const {
1140     return 0;
1141   }
1142 #endif
1143 
1144 #if defined (_LIBUNWIND_TARGET_MIPS_NEWABI)
dwarfEncoding(Registers_mips_newabi &) const1145   compact_unwind_encoding_t dwarfEncoding(Registers_mips_newabi &) const {
1146     return 0;
1147   }
1148 #endif
1149 
1150 #if defined(_LIBUNWIND_TARGET_SPARC)
dwarfEncoding(Registers_sparc &) const1151   compact_unwind_encoding_t dwarfEncoding(Registers_sparc &) const { return 0; }
1152 #endif
1153 
1154 #if defined (_LIBUNWIND_TARGET_RISCV)
dwarfEncoding(Registers_riscv &) const1155   compact_unwind_encoding_t dwarfEncoding(Registers_riscv &) const {
1156     return 0;
1157   }
1158 #endif
1159 
1160 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1161 
1162 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1163   // For runtime environments using SEH unwind data without Windows runtime
1164   // support.
getLastPC() const1165   pint_t getLastPC() const { /* FIXME: Implement */ return 0; }
setLastPC(pint_t pc)1166   void setLastPC(pint_t pc) { /* FIXME: Implement */ }
lookUpSEHUnwindInfo(pint_t pc,pint_t * base)1167   RUNTIME_FUNCTION *lookUpSEHUnwindInfo(pint_t pc, pint_t *base) {
1168     /* FIXME: Implement */
1169     *base = 0;
1170     return nullptr;
1171   }
1172   bool getInfoFromSEH(pint_t pc);
stepWithSEHData()1173   int stepWithSEHData() { /* FIXME: Implement */ return 0; }
1174 #endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1175 
1176 
1177   A               &_addressSpace;
1178   R                _registers;
1179   unw_proc_info_t  _info;
1180   bool             _unwindInfoMissing;
1181   bool             _isSignalFrame;
1182 };
1183 
1184 
1185 template <typename A, typename R>
UnwindCursor(unw_context_t * context,A & as)1186 UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
1187     : _addressSpace(as), _registers(context), _unwindInfoMissing(false),
1188       _isSignalFrame(false) {
1189   static_assert((check_fit<UnwindCursor<A, R>, unw_cursor_t>::does_fit),
1190                 "UnwindCursor<> does not fit in unw_cursor_t");
1191   static_assert((alignof(UnwindCursor<A, R>) <= alignof(unw_cursor_t)),
1192                 "UnwindCursor<> requires more alignment than unw_cursor_t");
1193   memset(&_info, 0, sizeof(_info));
1194 }
1195 
1196 template <typename A, typename R>
UnwindCursor(A & as,void *)1197 UnwindCursor<A, R>::UnwindCursor(A &as, void *)
1198     : _addressSpace(as), _unwindInfoMissing(false), _isSignalFrame(false) {
1199   memset(&_info, 0, sizeof(_info));
1200   // FIXME
1201   // fill in _registers from thread arg
1202 }
1203 
1204 
1205 template <typename A, typename R>
validReg(int regNum)1206 bool UnwindCursor<A, R>::validReg(int regNum) {
1207   return _registers.validRegister(regNum);
1208 }
1209 
1210 template <typename A, typename R>
getReg(int regNum)1211 unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
1212   return _registers.getRegister(regNum);
1213 }
1214 
1215 template <typename A, typename R>
setReg(int regNum,unw_word_t value)1216 void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
1217   _registers.setRegister(regNum, (typename A::pint_t)value);
1218 }
1219 
1220 template <typename A, typename R>
validFloatReg(int regNum)1221 bool UnwindCursor<A, R>::validFloatReg(int regNum) {
1222   return _registers.validFloatRegister(regNum);
1223 }
1224 
1225 template <typename A, typename R>
getFloatReg(int regNum)1226 unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
1227   return _registers.getFloatRegister(regNum);
1228 }
1229 
1230 template <typename A, typename R>
setFloatReg(int regNum,unw_fpreg_t value)1231 void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
1232   _registers.setFloatRegister(regNum, value);
1233 }
1234 
jumpto()1235 template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
1236   _registers.jumpto();
1237 }
1238 
1239 #ifdef __arm__
saveVFPAsX()1240 template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {
1241   _registers.saveVFPAsX();
1242 }
1243 #endif
1244 
1245 template <typename A, typename R>
getRegisterName(int regNum)1246 const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
1247   return _registers.getRegisterName(regNum);
1248 }
1249 
isSignalFrame()1250 template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
1251   return _isSignalFrame;
1252 }
1253 
1254 #endif // defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1255 
1256 #if defined(_LIBUNWIND_ARM_EHABI)
1257 template<typename A>
1258 struct EHABISectionIterator {
1259   typedef EHABISectionIterator _Self;
1260 
1261   typedef typename A::pint_t value_type;
1262   typedef typename A::pint_t* pointer;
1263   typedef typename A::pint_t& reference;
1264   typedef size_t size_type;
1265   typedef size_t difference_type;
1266 
beginlibunwind::EHABISectionIterator1267   static _Self begin(A& addressSpace, const UnwindInfoSections& sects) {
1268     return _Self(addressSpace, sects, 0);
1269   }
endlibunwind::EHABISectionIterator1270   static _Self end(A& addressSpace, const UnwindInfoSections& sects) {
1271     return _Self(addressSpace, sects,
1272                  sects.arm_section_length / sizeof(EHABIIndexEntry));
1273   }
1274 
EHABISectionIteratorlibunwind::EHABISectionIterator1275   EHABISectionIterator(A& addressSpace, const UnwindInfoSections& sects, size_t i)
1276       : _i(i), _addressSpace(&addressSpace), _sects(&sects) {}
1277 
operator ++libunwind::EHABISectionIterator1278   _Self& operator++() { ++_i; return *this; }
operator +=libunwind::EHABISectionIterator1279   _Self& operator+=(size_t a) { _i += a; return *this; }
operator --libunwind::EHABISectionIterator1280   _Self& operator--() { assert(_i > 0); --_i; return *this; }
operator -=libunwind::EHABISectionIterator1281   _Self& operator-=(size_t a) { assert(_i >= a); _i -= a; return *this; }
1282 
operator +libunwind::EHABISectionIterator1283   _Self operator+(size_t a) { _Self out = *this; out._i += a; return out; }
operator -libunwind::EHABISectionIterator1284   _Self operator-(size_t a) { assert(_i >= a); _Self out = *this; out._i -= a; return out; }
1285 
operator -libunwind::EHABISectionIterator1286   size_t operator-(const _Self& other) const { return _i - other._i; }
1287 
operator ==libunwind::EHABISectionIterator1288   bool operator==(const _Self& other) const {
1289     assert(_addressSpace == other._addressSpace);
1290     assert(_sects == other._sects);
1291     return _i == other._i;
1292   }
1293 
operator !=libunwind::EHABISectionIterator1294   bool operator!=(const _Self& other) const {
1295     assert(_addressSpace == other._addressSpace);
1296     assert(_sects == other._sects);
1297     return _i != other._i;
1298   }
1299 
operator *libunwind::EHABISectionIterator1300   typename A::pint_t operator*() const { return functionAddress(); }
1301 
functionAddresslibunwind::EHABISectionIterator1302   typename A::pint_t functionAddress() const {
1303     typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
1304         EHABIIndexEntry, _i, functionOffset);
1305     return indexAddr + signExtendPrel31(_addressSpace->get32(indexAddr));
1306   }
1307 
dataAddresslibunwind::EHABISectionIterator1308   typename A::pint_t dataAddress() {
1309     typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
1310         EHABIIndexEntry, _i, data);
1311     return indexAddr;
1312   }
1313 
1314  private:
1315   size_t _i;
1316   A* _addressSpace;
1317   const UnwindInfoSections* _sects;
1318 };
1319 
1320 namespace {
1321 
1322 template <typename A>
EHABISectionUpperBound(EHABISectionIterator<A> first,EHABISectionIterator<A> last,typename A::pint_t value)1323 EHABISectionIterator<A> EHABISectionUpperBound(
1324     EHABISectionIterator<A> first,
1325     EHABISectionIterator<A> last,
1326     typename A::pint_t value) {
1327   size_t len = last - first;
1328   while (len > 0) {
1329     size_t l2 = len / 2;
1330     EHABISectionIterator<A> m = first + l2;
1331     if (value < *m) {
1332         len = l2;
1333     } else {
1334         first = ++m;
1335         len -= l2 + 1;
1336     }
1337   }
1338   return first;
1339 }
1340 
1341 }
1342 
1343 template <typename A, typename R>
getInfoFromEHABISection(pint_t pc,const UnwindInfoSections & sects)1344 bool UnwindCursor<A, R>::getInfoFromEHABISection(
1345     pint_t pc,
1346     const UnwindInfoSections &sects) {
1347   EHABISectionIterator<A> begin =
1348       EHABISectionIterator<A>::begin(_addressSpace, sects);
1349   EHABISectionIterator<A> end =
1350       EHABISectionIterator<A>::end(_addressSpace, sects);
1351   if (begin == end)
1352     return false;
1353 
1354   EHABISectionIterator<A> itNextPC = EHABISectionUpperBound(begin, end, pc);
1355   if (itNextPC == begin)
1356     return false;
1357   EHABISectionIterator<A> itThisPC = itNextPC - 1;
1358 
1359   pint_t thisPC = itThisPC.functionAddress();
1360   // If an exception is thrown from a function, corresponding to the last entry
1361   // in the table, we don't really know the function extent and have to choose a
1362   // value for nextPC. Choosing max() will allow the range check during trace to
1363   // succeed.
1364   pint_t nextPC = (itNextPC == end) ? UINTPTR_MAX : itNextPC.functionAddress();
1365   pint_t indexDataAddr = itThisPC.dataAddress();
1366 
1367   if (indexDataAddr == 0)
1368     return false;
1369 
1370   uint32_t indexData = _addressSpace.get32(indexDataAddr);
1371   if (indexData == UNW_EXIDX_CANTUNWIND)
1372     return false;
1373 
1374   // If the high bit is set, the exception handling table entry is inline inside
1375   // the index table entry on the second word (aka |indexDataAddr|). Otherwise,
1376   // the table points at an offset in the exception handling table (section 5
1377   // EHABI).
1378   pint_t exceptionTableAddr;
1379   uint32_t exceptionTableData;
1380   bool isSingleWordEHT;
1381   if (indexData & 0x80000000) {
1382     exceptionTableAddr = indexDataAddr;
1383     // TODO(ajwong): Should this data be 0?
1384     exceptionTableData = indexData;
1385     isSingleWordEHT = true;
1386   } else {
1387     exceptionTableAddr = indexDataAddr + signExtendPrel31(indexData);
1388     exceptionTableData = _addressSpace.get32(exceptionTableAddr);
1389     isSingleWordEHT = false;
1390   }
1391 
1392   // Now we know the 3 things:
1393   //   exceptionTableAddr -- exception handler table entry.
1394   //   exceptionTableData -- the data inside the first word of the eht entry.
1395   //   isSingleWordEHT -- whether the entry is in the index.
1396   unw_word_t personalityRoutine = 0xbadf00d;
1397   bool scope32 = false;
1398   uintptr_t lsda;
1399 
1400   // If the high bit in the exception handling table entry is set, the entry is
1401   // in compact form (section 6.3 EHABI).
1402   if (exceptionTableData & 0x80000000) {
1403     // Grab the index of the personality routine from the compact form.
1404     uint32_t choice = (exceptionTableData & 0x0f000000) >> 24;
1405     uint32_t extraWords = 0;
1406     switch (choice) {
1407       case 0:
1408         personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr0;
1409         extraWords = 0;
1410         scope32 = false;
1411         lsda = isSingleWordEHT ? 0 : (exceptionTableAddr + 4);
1412         break;
1413       case 1:
1414         personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr1;
1415         extraWords = (exceptionTableData & 0x00ff0000) >> 16;
1416         scope32 = false;
1417         lsda = exceptionTableAddr + (extraWords + 1) * 4;
1418         break;
1419       case 2:
1420         personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr2;
1421         extraWords = (exceptionTableData & 0x00ff0000) >> 16;
1422         scope32 = true;
1423         lsda = exceptionTableAddr + (extraWords + 1) * 4;
1424         break;
1425       default:
1426         _LIBUNWIND_ABORT("unknown personality routine");
1427         return false;
1428     }
1429 
1430     if (isSingleWordEHT) {
1431       if (extraWords != 0) {
1432         _LIBUNWIND_ABORT("index inlined table detected but pr function "
1433                          "requires extra words");
1434         return false;
1435       }
1436     }
1437   } else {
1438     pint_t personalityAddr =
1439         exceptionTableAddr + signExtendPrel31(exceptionTableData);
1440     personalityRoutine = personalityAddr;
1441 
1442     // ARM EHABI # 6.2, # 9.2
1443     //
1444     //  +---- ehtp
1445     //  v
1446     // +--------------------------------------+
1447     // | +--------+--------+--------+-------+ |
1448     // | |0| prel31 to personalityRoutine   | |
1449     // | +--------+--------+--------+-------+ |
1450     // | |      N |      unwind opcodes     | |  <-- UnwindData
1451     // | +--------+--------+--------+-------+ |
1452     // | | Word 2        unwind opcodes     | |
1453     // | +--------+--------+--------+-------+ |
1454     // | ...                                  |
1455     // | +--------+--------+--------+-------+ |
1456     // | | Word N        unwind opcodes     | |
1457     // | +--------+--------+--------+-------+ |
1458     // | | LSDA                             | |  <-- lsda
1459     // | | ...                              | |
1460     // | +--------+--------+--------+-------+ |
1461     // +--------------------------------------+
1462 
1463     uint32_t *UnwindData = reinterpret_cast<uint32_t*>(exceptionTableAddr) + 1;
1464     uint32_t FirstDataWord = *UnwindData;
1465     size_t N = ((FirstDataWord >> 24) & 0xff);
1466     size_t NDataWords = N + 1;
1467     lsda = reinterpret_cast<uintptr_t>(UnwindData + NDataWords);
1468   }
1469 
1470   _info.start_ip = thisPC;
1471   _info.end_ip = nextPC;
1472   _info.handler = personalityRoutine;
1473   _info.unwind_info = exceptionTableAddr;
1474   _info.lsda = lsda;
1475   // flags is pr_cache.additional. See EHABI #7.2 for definition of bit 0.
1476   _info.flags = (isSingleWordEHT ? 1 : 0) | (scope32 ? 0x2 : 0);  // Use enum?
1477 
1478   return true;
1479 }
1480 #endif
1481 
1482 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1483 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)1484 bool UnwindCursor<A, R>::getInfoFromFdeCie(
1485     const typename CFI_Parser<A>::FDE_Info &fdeInfo,
1486     const typename CFI_Parser<A>::CIE_Info &cieInfo, pint_t pc,
1487     uintptr_t dso_base) {
1488   typename CFI_Parser<A>::PrologInfo prolog;
1489   if (CFI_Parser<A>::parseFDEInstructions(_addressSpace, fdeInfo, cieInfo, pc,
1490                                           R::getArch(), &prolog)) {
1491     // Save off parsed FDE info
1492     _info.start_ip          = fdeInfo.pcStart;
1493     _info.end_ip            = fdeInfo.pcEnd;
1494     _info.lsda              = fdeInfo.lsda;
1495     _info.handler           = cieInfo.personality;
1496     // Some frameless functions need SP altered when resuming in function, so
1497     // propagate spExtraArgSize.
1498     _info.gp                = prolog.spExtraArgSize;
1499     _info.flags             = 0;
1500     _info.format            = dwarfEncoding();
1501     _info.unwind_info       = fdeInfo.fdeStart;
1502     _info.unwind_info_size  = static_cast<uint32_t>(fdeInfo.fdeLength);
1503     _info.extra             = static_cast<unw_word_t>(dso_base);
1504     return true;
1505   }
1506   return false;
1507 }
1508 
1509 template <typename A, typename R>
getInfoFromDwarfSection(pint_t pc,const UnwindInfoSections & sects,uint32_t fdeSectionOffsetHint)1510 bool UnwindCursor<A, R>::getInfoFromDwarfSection(pint_t pc,
1511                                                 const UnwindInfoSections &sects,
1512                                                 uint32_t fdeSectionOffsetHint) {
1513   typename CFI_Parser<A>::FDE_Info fdeInfo;
1514   typename CFI_Parser<A>::CIE_Info cieInfo;
1515   bool foundFDE = false;
1516   bool foundInCache = false;
1517   // If compact encoding table gave offset into dwarf section, go directly there
1518   if (fdeSectionOffsetHint != 0) {
1519     foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1520                                     sects.dwarf_section_length,
1521                                     sects.dwarf_section + fdeSectionOffsetHint,
1522                                     &fdeInfo, &cieInfo);
1523   }
1524 #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
1525   if (!foundFDE && (sects.dwarf_index_section != 0)) {
1526     foundFDE = EHHeaderParser<A>::findFDE(
1527         _addressSpace, pc, sects.dwarf_index_section,
1528         (uint32_t)sects.dwarf_index_section_length, &fdeInfo, &cieInfo);
1529   }
1530 #endif
1531   if (!foundFDE) {
1532     // otherwise, search cache of previously found FDEs.
1533     pint_t cachedFDE = DwarfFDECache<A>::findFDE(sects.dso_base, pc);
1534     if (cachedFDE != 0) {
1535       foundFDE =
1536           CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1537                                  sects.dwarf_section_length,
1538                                  cachedFDE, &fdeInfo, &cieInfo);
1539       foundInCache = foundFDE;
1540     }
1541   }
1542   if (!foundFDE) {
1543     // Still not found, do full scan of __eh_frame section.
1544     foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
1545                                       sects.dwarf_section_length, 0,
1546                                       &fdeInfo, &cieInfo);
1547   }
1548   if (foundFDE) {
1549     if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, sects.dso_base)) {
1550       // Add to cache (to make next lookup faster) if we had no hint
1551       // and there was no index.
1552       if (!foundInCache && (fdeSectionOffsetHint == 0)) {
1553   #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
1554         if (sects.dwarf_index_section == 0)
1555   #endif
1556         DwarfFDECache<A>::add(sects.dso_base, fdeInfo.pcStart, fdeInfo.pcEnd,
1557                               fdeInfo.fdeStart);
1558       }
1559       return true;
1560     }
1561   }
1562   //_LIBUNWIND_DEBUG_LOG("can't find/use FDE for pc=0x%llX", (uint64_t)pc);
1563   return false;
1564 }
1565 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1566 
1567 
1568 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1569 template <typename A, typename R>
getInfoFromCompactEncodingSection(pint_t pc,const UnwindInfoSections & sects)1570 bool UnwindCursor<A, R>::getInfoFromCompactEncodingSection(pint_t pc,
1571                                               const UnwindInfoSections &sects) {
1572   const bool log = false;
1573   if (log)
1574     fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX, mh=0x%llX)\n",
1575             (uint64_t)pc, (uint64_t)sects.dso_base);
1576 
1577   const UnwindSectionHeader<A> sectionHeader(_addressSpace,
1578                                                 sects.compact_unwind_section);
1579   if (sectionHeader.version() != UNWIND_SECTION_VERSION)
1580     return false;
1581 
1582   // do a binary search of top level index to find page with unwind info
1583   pint_t targetFunctionOffset = pc - sects.dso_base;
1584   const UnwindSectionIndexArray<A> topIndex(_addressSpace,
1585                                            sects.compact_unwind_section
1586                                          + sectionHeader.indexSectionOffset());
1587   uint32_t low = 0;
1588   uint32_t high = sectionHeader.indexCount();
1589   uint32_t last = high - 1;
1590   while (low < high) {
1591     uint32_t mid = (low + high) / 2;
1592     //if ( log ) fprintf(stderr, "\tmid=%d, low=%d, high=%d, *mid=0x%08X\n",
1593     //mid, low, high, topIndex.functionOffset(mid));
1594     if (topIndex.functionOffset(mid) <= targetFunctionOffset) {
1595       if ((mid == last) ||
1596           (topIndex.functionOffset(mid + 1) > targetFunctionOffset)) {
1597         low = mid;
1598         break;
1599       } else {
1600         low = mid + 1;
1601       }
1602     } else {
1603       high = mid;
1604     }
1605   }
1606   const uint32_t firstLevelFunctionOffset = topIndex.functionOffset(low);
1607   const uint32_t firstLevelNextPageFunctionOffset =
1608       topIndex.functionOffset(low + 1);
1609   const pint_t secondLevelAddr =
1610       sects.compact_unwind_section + topIndex.secondLevelPagesSectionOffset(low);
1611   const pint_t lsdaArrayStartAddr =
1612       sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low);
1613   const pint_t lsdaArrayEndAddr =
1614       sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low+1);
1615   if (log)
1616     fprintf(stderr, "\tfirst level search for result index=%d "
1617                     "to secondLevelAddr=0x%llX\n",
1618                     low, (uint64_t) secondLevelAddr);
1619   // do a binary search of second level page index
1620   uint32_t encoding = 0;
1621   pint_t funcStart = 0;
1622   pint_t funcEnd = 0;
1623   pint_t lsda = 0;
1624   pint_t personality = 0;
1625   uint32_t pageKind = _addressSpace.get32(secondLevelAddr);
1626   if (pageKind == UNWIND_SECOND_LEVEL_REGULAR) {
1627     // regular page
1628     UnwindSectionRegularPageHeader<A> pageHeader(_addressSpace,
1629                                                  secondLevelAddr);
1630     UnwindSectionRegularArray<A> pageIndex(
1631         _addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
1632     // binary search looks for entry with e where index[e].offset <= pc <
1633     // index[e+1].offset
1634     if (log)
1635       fprintf(stderr, "\tbinary search for targetFunctionOffset=0x%08llX in "
1636                       "regular page starting at secondLevelAddr=0x%llX\n",
1637               (uint64_t) targetFunctionOffset, (uint64_t) secondLevelAddr);
1638     low = 0;
1639     high = pageHeader.entryCount();
1640     while (low < high) {
1641       uint32_t mid = (low + high) / 2;
1642       if (pageIndex.functionOffset(mid) <= targetFunctionOffset) {
1643         if (mid == (uint32_t)(pageHeader.entryCount() - 1)) {
1644           // at end of table
1645           low = mid;
1646           funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
1647           break;
1648         } else if (pageIndex.functionOffset(mid + 1) > targetFunctionOffset) {
1649           // next is too big, so we found it
1650           low = mid;
1651           funcEnd = pageIndex.functionOffset(low + 1) + sects.dso_base;
1652           break;
1653         } else {
1654           low = mid + 1;
1655         }
1656       } else {
1657         high = mid;
1658       }
1659     }
1660     encoding = pageIndex.encoding(low);
1661     funcStart = pageIndex.functionOffset(low) + sects.dso_base;
1662     if (pc < funcStart) {
1663       if (log)
1664         fprintf(
1665             stderr,
1666             "\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
1667             (uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
1668       return false;
1669     }
1670     if (pc > funcEnd) {
1671       if (log)
1672         fprintf(
1673             stderr,
1674             "\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
1675             (uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
1676       return false;
1677     }
1678   } else if (pageKind == UNWIND_SECOND_LEVEL_COMPRESSED) {
1679     // compressed page
1680     UnwindSectionCompressedPageHeader<A> pageHeader(_addressSpace,
1681                                                     secondLevelAddr);
1682     UnwindSectionCompressedArray<A> pageIndex(
1683         _addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
1684     const uint32_t targetFunctionPageOffset =
1685         (uint32_t)(targetFunctionOffset - firstLevelFunctionOffset);
1686     // binary search looks for entry with e where index[e].offset <= pc <
1687     // index[e+1].offset
1688     if (log)
1689       fprintf(stderr, "\tbinary search of compressed page starting at "
1690                       "secondLevelAddr=0x%llX\n",
1691               (uint64_t) secondLevelAddr);
1692     low = 0;
1693     last = pageHeader.entryCount() - 1;
1694     high = pageHeader.entryCount();
1695     while (low < high) {
1696       uint32_t mid = (low + high) / 2;
1697       if (pageIndex.functionOffset(mid) <= targetFunctionPageOffset) {
1698         if ((mid == last) ||
1699             (pageIndex.functionOffset(mid + 1) > targetFunctionPageOffset)) {
1700           low = mid;
1701           break;
1702         } else {
1703           low = mid + 1;
1704         }
1705       } else {
1706         high = mid;
1707       }
1708     }
1709     funcStart = pageIndex.functionOffset(low) + firstLevelFunctionOffset
1710                                                               + sects.dso_base;
1711     if (low < last)
1712       funcEnd =
1713           pageIndex.functionOffset(low + 1) + firstLevelFunctionOffset
1714                                                               + sects.dso_base;
1715     else
1716       funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
1717     if (pc < funcStart) {
1718       _LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX not in second  "
1719                            "level compressed unwind table. funcStart=0x%llX",
1720                             (uint64_t) pc, (uint64_t) funcStart);
1721       return false;
1722     }
1723     if (pc > funcEnd) {
1724       _LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX not in second  "
1725                           "level compressed unwind table. funcEnd=0x%llX",
1726                            (uint64_t) pc, (uint64_t) funcEnd);
1727       return false;
1728     }
1729     uint16_t encodingIndex = pageIndex.encodingIndex(low);
1730     if (encodingIndex < sectionHeader.commonEncodingsArrayCount()) {
1731       // encoding is in common table in section header
1732       encoding = _addressSpace.get32(
1733           sects.compact_unwind_section +
1734           sectionHeader.commonEncodingsArraySectionOffset() +
1735           encodingIndex * sizeof(uint32_t));
1736     } else {
1737       // encoding is in page specific table
1738       uint16_t pageEncodingIndex =
1739           encodingIndex - (uint16_t)sectionHeader.commonEncodingsArrayCount();
1740       encoding = _addressSpace.get32(secondLevelAddr +
1741                                      pageHeader.encodingsPageOffset() +
1742                                      pageEncodingIndex * sizeof(uint32_t));
1743     }
1744   } else {
1745     _LIBUNWIND_DEBUG_LOG("malformed __unwind_info at 0x%0llX bad second "
1746                          "level page",
1747                           (uint64_t) sects.compact_unwind_section);
1748     return false;
1749   }
1750 
1751   // look up LSDA, if encoding says function has one
1752   if (encoding & UNWIND_HAS_LSDA) {
1753     UnwindSectionLsdaArray<A> lsdaIndex(_addressSpace, lsdaArrayStartAddr);
1754     uint32_t funcStartOffset = (uint32_t)(funcStart - sects.dso_base);
1755     low = 0;
1756     high = (uint32_t)(lsdaArrayEndAddr - lsdaArrayStartAddr) /
1757                     sizeof(unwind_info_section_header_lsda_index_entry);
1758     // binary search looks for entry with exact match for functionOffset
1759     if (log)
1760       fprintf(stderr,
1761               "\tbinary search of lsda table for targetFunctionOffset=0x%08X\n",
1762               funcStartOffset);
1763     while (low < high) {
1764       uint32_t mid = (low + high) / 2;
1765       if (lsdaIndex.functionOffset(mid) == funcStartOffset) {
1766         lsda = lsdaIndex.lsdaOffset(mid) + sects.dso_base;
1767         break;
1768       } else if (lsdaIndex.functionOffset(mid) < funcStartOffset) {
1769         low = mid + 1;
1770       } else {
1771         high = mid;
1772       }
1773     }
1774     if (lsda == 0) {
1775       _LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with HAS_LSDA bit set for "
1776                     "pc=0x%0llX, but lsda table has no entry",
1777                     encoding, (uint64_t) pc);
1778       return false;
1779     }
1780   }
1781 
1782   // extract personality routine, if encoding says function has one
1783   uint32_t personalityIndex = (encoding & UNWIND_PERSONALITY_MASK) >>
1784                               (__builtin_ctz(UNWIND_PERSONALITY_MASK));
1785   if (personalityIndex != 0) {
1786     --personalityIndex; // change 1-based to zero-based index
1787     if (personalityIndex >= sectionHeader.personalityArrayCount()) {
1788       _LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with personality index %d,  "
1789                             "but personality table has only %d entries",
1790                             encoding, personalityIndex,
1791                             sectionHeader.personalityArrayCount());
1792       return false;
1793     }
1794     int32_t personalityDelta = (int32_t)_addressSpace.get32(
1795         sects.compact_unwind_section +
1796         sectionHeader.personalityArraySectionOffset() +
1797         personalityIndex * sizeof(uint32_t));
1798     pint_t personalityPointer = sects.dso_base + (pint_t)personalityDelta;
1799     personality = _addressSpace.getP(personalityPointer);
1800     if (log)
1801       fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
1802                       "personalityDelta=0x%08X, personality=0x%08llX\n",
1803               (uint64_t) pc, personalityDelta, (uint64_t) personality);
1804   }
1805 
1806   if (log)
1807     fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
1808                     "encoding=0x%08X, lsda=0x%08llX for funcStart=0x%llX\n",
1809             (uint64_t) pc, encoding, (uint64_t) lsda, (uint64_t) funcStart);
1810   _info.start_ip = funcStart;
1811   _info.end_ip = funcEnd;
1812   _info.lsda = lsda;
1813   _info.handler = personality;
1814   _info.gp = 0;
1815   _info.flags = 0;
1816   _info.format = encoding;
1817   _info.unwind_info = 0;
1818   _info.unwind_info_size = 0;
1819   _info.extra = sects.dso_base;
1820   return true;
1821 }
1822 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1823 
1824 
1825 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1826 template <typename A, typename R>
getInfoFromSEH(pint_t pc)1827 bool UnwindCursor<A, R>::getInfoFromSEH(pint_t pc) {
1828   pint_t base;
1829   RUNTIME_FUNCTION *unwindEntry = lookUpSEHUnwindInfo(pc, &base);
1830   if (!unwindEntry) {
1831     _LIBUNWIND_DEBUG_LOG("\tpc not in table, pc=0x%llX", (uint64_t) pc);
1832     return false;
1833   }
1834   _info.gp = 0;
1835   _info.flags = 0;
1836   _info.format = 0;
1837   _info.unwind_info_size = sizeof(RUNTIME_FUNCTION);
1838   _info.unwind_info = reinterpret_cast<unw_word_t>(unwindEntry);
1839   _info.extra = base;
1840   _info.start_ip = base + unwindEntry->BeginAddress;
1841 #ifdef _LIBUNWIND_TARGET_X86_64
1842   _info.end_ip = base + unwindEntry->EndAddress;
1843   // Only fill in the handler and LSDA if they're stale.
1844   if (pc != getLastPC()) {
1845     UNWIND_INFO *xdata = reinterpret_cast<UNWIND_INFO *>(base + unwindEntry->UnwindData);
1846     if (xdata->Flags & (UNW_FLAG_EHANDLER|UNW_FLAG_UHANDLER)) {
1847       // The personality is given in the UNWIND_INFO itself. The LSDA immediately
1848       // follows the UNWIND_INFO. (This follows how both Clang and MSVC emit
1849       // these structures.)
1850       // N.B. UNWIND_INFO structs are DWORD-aligned.
1851       uint32_t lastcode = (xdata->CountOfCodes + 1) & ~1;
1852       const uint32_t *handler = reinterpret_cast<uint32_t *>(&xdata->UnwindCodes[lastcode]);
1853       _info.lsda = reinterpret_cast<unw_word_t>(handler+1);
1854       if (*handler) {
1855         _info.handler = reinterpret_cast<unw_word_t>(__libunwind_seh_personality);
1856       } else
1857         _info.handler = 0;
1858     } else {
1859       _info.lsda = 0;
1860       _info.handler = 0;
1861     }
1862   }
1863 #elif defined(_LIBUNWIND_TARGET_ARM)
1864   _info.end_ip = _info.start_ip + unwindEntry->FunctionLength;
1865   _info.lsda = 0; // FIXME
1866   _info.handler = 0; // FIXME
1867 #endif
1868   setLastPC(pc);
1869   return true;
1870 }
1871 #endif
1872 
1873 
1874 template <typename A, typename R>
setInfoBasedOnIPRegister(bool isReturnAddress)1875 void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
1876   pint_t pc = (pint_t)this->getReg(UNW_REG_IP);
1877 #if defined(_LIBUNWIND_ARM_EHABI)
1878   // Remove the thumb bit so the IP represents the actual instruction address.
1879   // This matches the behaviour of _Unwind_GetIP on arm.
1880   pc &= (pint_t)~0x1;
1881 #endif
1882 
1883   // Exit early if at the top of the stack.
1884   if (pc == 0) {
1885     _unwindInfoMissing = true;
1886     return;
1887   }
1888 
1889   // If the last line of a function is a "throw" the compiler sometimes
1890   // emits no instructions after the call to __cxa_throw.  This means
1891   // the return address is actually the start of the next function.
1892   // To disambiguate this, back up the pc when we know it is a return
1893   // address.
1894   if (isReturnAddress)
1895     --pc;
1896 
1897   // Ask address space object to find unwind sections for this pc.
1898   UnwindInfoSections sects;
1899   if (_addressSpace.findUnwindSections(pc, sects)) {
1900 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1901     // If there is a compact unwind encoding table, look there first.
1902     if (sects.compact_unwind_section != 0) {
1903       if (this->getInfoFromCompactEncodingSection(pc, sects)) {
1904   #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1905         // Found info in table, done unless encoding says to use dwarf.
1906         uint32_t dwarfOffset;
1907         if ((sects.dwarf_section != 0) && compactSaysUseDwarf(&dwarfOffset)) {
1908           if (this->getInfoFromDwarfSection(pc, sects, dwarfOffset)) {
1909             // found info in dwarf, done
1910             return;
1911           }
1912         }
1913   #endif
1914         // If unwind table has entry, but entry says there is no unwind info,
1915         // record that we have no unwind info.
1916         if (_info.format == 0)
1917           _unwindInfoMissing = true;
1918         return;
1919       }
1920     }
1921 #endif // defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1922 
1923 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1924     // If there is SEH unwind info, look there next.
1925     if (this->getInfoFromSEH(pc))
1926       return;
1927 #endif
1928 
1929 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1930     // If there is dwarf unwind info, look there next.
1931     if (sects.dwarf_section != 0) {
1932       if (this->getInfoFromDwarfSection(pc, sects)) {
1933         // found info in dwarf, done
1934         return;
1935       }
1936     }
1937 #endif
1938 
1939 #if defined(_LIBUNWIND_ARM_EHABI)
1940     // If there is ARM EHABI unwind info, look there next.
1941     if (sects.arm_section != 0 && this->getInfoFromEHABISection(pc, sects))
1942       return;
1943 #endif
1944   }
1945 
1946 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1947   // There is no static unwind info for this pc. Look to see if an FDE was
1948   // dynamically registered for it.
1949   pint_t cachedFDE = DwarfFDECache<A>::findFDE(DwarfFDECache<A>::kSearchAll,
1950                                                pc);
1951   if (cachedFDE != 0) {
1952     typename CFI_Parser<A>::FDE_Info fdeInfo;
1953     typename CFI_Parser<A>::CIE_Info cieInfo;
1954     if (!CFI_Parser<A>::decodeFDE(_addressSpace, cachedFDE, &fdeInfo, &cieInfo))
1955       if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, 0))
1956         return;
1957   }
1958 
1959   // Lastly, ask AddressSpace object about platform specific ways to locate
1960   // other FDEs.
1961   pint_t fde;
1962   if (_addressSpace.findOtherFDE(pc, fde)) {
1963     typename CFI_Parser<A>::FDE_Info fdeInfo;
1964     typename CFI_Parser<A>::CIE_Info cieInfo;
1965     if (!CFI_Parser<A>::decodeFDE(_addressSpace, fde, &fdeInfo, &cieInfo)) {
1966       // Double check this FDE is for a function that includes the pc.
1967       if ((fdeInfo.pcStart <= pc) && (pc < fdeInfo.pcEnd))
1968         if (getInfoFromFdeCie(fdeInfo, cieInfo, pc, 0))
1969           return;
1970     }
1971   }
1972 #endif // #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1973 
1974   // no unwind info, flag that we can't reliably unwind
1975   _unwindInfoMissing = true;
1976 }
1977 
1978 template <typename A, typename R>
step()1979 int UnwindCursor<A, R>::step() {
1980   // Bottom of stack is defined is when unwind info cannot be found.
1981   if (_unwindInfoMissing)
1982     return UNW_STEP_END;
1983 
1984   // Use unwinding info to modify register set as if function returned.
1985   int result;
1986 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
1987   result = this->stepWithCompactEncoding();
1988 #elif defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
1989   result = this->stepWithSEHData();
1990 #elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
1991   result = this->stepWithDwarfFDE();
1992 #elif defined(_LIBUNWIND_ARM_EHABI)
1993   result = this->stepWithEHABI();
1994 #else
1995   #error Need _LIBUNWIND_SUPPORT_COMPACT_UNWIND or \
1996               _LIBUNWIND_SUPPORT_SEH_UNWIND or \
1997               _LIBUNWIND_SUPPORT_DWARF_UNWIND or \
1998               _LIBUNWIND_ARM_EHABI
1999 #endif
2000 
2001   // update info based on new PC
2002   if (result == UNW_STEP_SUCCESS) {
2003     this->setInfoBasedOnIPRegister(true);
2004     if (_unwindInfoMissing)
2005       return UNW_STEP_END;
2006   }
2007 
2008   return result;
2009 }
2010 
2011 template <typename A, typename R>
getInfo(unw_proc_info_t * info)2012 void UnwindCursor<A, R>::getInfo(unw_proc_info_t *info) {
2013   if (_unwindInfoMissing)
2014     memset(info, 0, sizeof(*info));
2015   else
2016     *info = _info;
2017 }
2018 
2019 template <typename A, typename R>
getFunctionName(char * buf,size_t bufLen,unw_word_t * offset)2020 bool UnwindCursor<A, R>::getFunctionName(char *buf, size_t bufLen,
2021                                                            unw_word_t *offset) {
2022   return _addressSpace.findFunctionName((pint_t)this->getReg(UNW_REG_IP),
2023                                          buf, bufLen, offset);
2024 }
2025 
2026 } // namespace libunwind
2027 
2028 #endif // __UNWINDCURSOR_HPP__
2029