//===------------------------- UnwindCursor.hpp ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//
// C++ interface to lower levels of libuwind
//===----------------------------------------------------------------------===//
#ifndef __UNWINDCURSOR_HPP__
#define __UNWINDCURSOR_HPP__
#include <algorithm>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unwind.h>
#ifdef __APPLE__
#include <mach-o/dyld.h>
#endif
#include "config.h"
#include "AddressSpace.hpp"
#include "CompactUnwinder.hpp"
#include "config.h"
#include "DwarfInstructions.hpp"
#include "EHHeaderParser.hpp"
#include "libunwind.h"
#include "Registers.hpp"
#include "Unwind-EHABI.h"
namespace libunwind {
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
/// Cache of recently found FDEs.
template <typename A>
class _LIBUNWIND_HIDDEN DwarfFDECache {
typedef typename A::pint_t pint_t;
public:
static pint_t findFDE(pint_t mh, pint_t pc);
static void add(pint_t mh, pint_t ip_start, pint_t ip_end, pint_t fde);
static void removeAllIn(pint_t mh);
static void iterateCacheEntries(void (*func)(unw_word_t ip_start,
unw_word_t ip_end,
unw_word_t fde, unw_word_t mh));
private:
struct entry {
pint_t mh;
pint_t ip_start;
pint_t ip_end;
pint_t fde;
};
// These fields are all static to avoid needing an initializer.
// There is only one instance of this class per process.
static pthread_rwlock_t _lock;
#ifdef __APPLE__
static void dyldUnloadHook(const struct mach_header *mh, intptr_t slide);
static bool _registeredForDyldUnloads;
#endif
// Can't use std::vector<> here because this code is below libc++.
static entry *_buffer;
static entry *_bufferUsed;
static entry *_bufferEnd;
static entry _initialBuffer[64];
};
template <typename A>
typename DwarfFDECache<A>::entry *
DwarfFDECache<A>::_buffer = _initialBuffer;
template <typename A>
typename DwarfFDECache<A>::entry *
DwarfFDECache<A>::_bufferUsed = _initialBuffer;
template <typename A>
typename DwarfFDECache<A>::entry *
DwarfFDECache<A>::_bufferEnd = &_initialBuffer[64];
template <typename A>
typename DwarfFDECache<A>::entry DwarfFDECache<A>::_initialBuffer[64];
template <typename A>
pthread_rwlock_t DwarfFDECache<A>::_lock = PTHREAD_RWLOCK_INITIALIZER;
#ifdef __APPLE__
template <typename A>
bool DwarfFDECache<A>::_registeredForDyldUnloads = false;
#endif
template <typename A>
typename A::pint_t DwarfFDECache<A>::findFDE(pint_t mh, pint_t pc) {
pint_t result = 0;
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_rdlock(&_lock));
for (entry *p = _buffer; p < _bufferUsed; ++p) {
if ((mh == p->mh) || (mh == 0)) {
if ((p->ip_start <= pc) && (pc < p->ip_end)) {
result = p->fde;
break;
}
}
}
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
return result;
}
template <typename A>
void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
pint_t fde) {
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_wrlock(&_lock));
if (_bufferUsed >= _bufferEnd) {
size_t oldSize = (size_t)(_bufferEnd - _buffer);
size_t newSize = oldSize * 4;
// Can't use operator new (we are below it).
entry *newBuffer = (entry *)malloc(newSize * sizeof(entry));
memcpy(newBuffer, _buffer, oldSize * sizeof(entry));
if (_buffer != _initialBuffer)
free(_buffer);
_buffer = newBuffer;
_bufferUsed = &newBuffer[oldSize];
_bufferEnd = &newBuffer[newSize];
}
_bufferUsed->mh = mh;
_bufferUsed->ip_start = ip_start;
_bufferUsed->ip_end = ip_end;
_bufferUsed->fde = fde;
++_bufferUsed;
#ifdef __APPLE__
if (!_registeredForDyldUnloads) {
_dyld_register_func_for_remove_image(&dyldUnloadHook);
_registeredForDyldUnloads = true;
}
#endif
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
}
template <typename A>
void DwarfFDECache<A>::removeAllIn(pint_t mh) {
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_wrlock(&_lock));
entry *d = _buffer;
for (const entry *s = _buffer; s < _bufferUsed; ++s) {
if (s->mh != mh) {
if (d != s)
*d = *s;
++d;
}
}
_bufferUsed = d;
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
}
#ifdef __APPLE__
template <typename A>
void DwarfFDECache<A>::dyldUnloadHook(const struct mach_header *mh, intptr_t ) {
removeAllIn((pint_t) mh);
}
#endif
template <typename A>
void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_wrlock(&_lock));
for (entry *p = _buffer; p < _bufferUsed; ++p) {
(*func)(p->ip_start, p->ip_end, p->fde, p->mh);
}
_LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
}
#endif // _LIBUNWIND_SUPPORT_DWARF_UNWIND
#define arrayoffsetof(type, index, field) ((size_t)(&((type *)0)[index].field))
#if _LIBUNWIND_SUPPORT_COMPACT_UNWIND
template <typename A> class UnwindSectionHeader {
public:
UnwindSectionHeader(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t version() const {
return _addressSpace.get32(_addr +
offsetof(unwind_info_section_header, version));
}
uint32_t commonEncodingsArraySectionOffset() const {
return _addressSpace.get32(_addr +
offsetof(unwind_info_section_header,
commonEncodingsArraySectionOffset));
}
uint32_t commonEncodingsArrayCount() const {
return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
commonEncodingsArrayCount));
}
uint32_t personalityArraySectionOffset() const {
return _addressSpace.get32(_addr + offsetof(unwind_info_section_header,
personalityArraySectionOffset));
}
uint32_t personalityArrayCount() const {
return _addressSpace.get32(
_addr + offsetof(unwind_info_section_header, personalityArrayCount));
}
uint32_t indexSectionOffset() const {
return _addressSpace.get32(
_addr + offsetof(unwind_info_section_header, indexSectionOffset));
}
uint32_t indexCount() const {
return _addressSpace.get32(
_addr + offsetof(unwind_info_section_header, indexCount));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
template <typename A> class UnwindSectionIndexArray {
public:
UnwindSectionIndexArray(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t functionOffset(uint32_t index) const {
return _addressSpace.get32(
_addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
functionOffset));
}
uint32_t secondLevelPagesSectionOffset(uint32_t index) const {
return _addressSpace.get32(
_addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
secondLevelPagesSectionOffset));
}
uint32_t lsdaIndexArraySectionOffset(uint32_t index) const {
return _addressSpace.get32(
_addr + arrayoffsetof(unwind_info_section_header_index_entry, index,
lsdaIndexArraySectionOffset));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
template <typename A> class UnwindSectionRegularPageHeader {
public:
UnwindSectionRegularPageHeader(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t kind() const {
return _addressSpace.get32(
_addr + offsetof(unwind_info_regular_second_level_page_header, kind));
}
uint16_t entryPageOffset() const {
return _addressSpace.get16(
_addr + offsetof(unwind_info_regular_second_level_page_header,
entryPageOffset));
}
uint16_t entryCount() const {
return _addressSpace.get16(
_addr +
offsetof(unwind_info_regular_second_level_page_header, entryCount));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
template <typename A> class UnwindSectionRegularArray {
public:
UnwindSectionRegularArray(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t functionOffset(uint32_t index) const {
return _addressSpace.get32(
_addr + arrayoffsetof(unwind_info_regular_second_level_entry, index,
functionOffset));
}
uint32_t encoding(uint32_t index) const {
return _addressSpace.get32(
_addr +
arrayoffsetof(unwind_info_regular_second_level_entry, index, encoding));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
template <typename A> class UnwindSectionCompressedPageHeader {
public:
UnwindSectionCompressedPageHeader(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t kind() const {
return _addressSpace.get32(
_addr +
offsetof(unwind_info_compressed_second_level_page_header, kind));
}
uint16_t entryPageOffset() const {
return _addressSpace.get16(
_addr + offsetof(unwind_info_compressed_second_level_page_header,
entryPageOffset));
}
uint16_t entryCount() const {
return _addressSpace.get16(
_addr +
offsetof(unwind_info_compressed_second_level_page_header, entryCount));
}
uint16_t encodingsPageOffset() const {
return _addressSpace.get16(
_addr + offsetof(unwind_info_compressed_second_level_page_header,
encodingsPageOffset));
}
uint16_t encodingsCount() const {
return _addressSpace.get16(
_addr + offsetof(unwind_info_compressed_second_level_page_header,
encodingsCount));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
template <typename A> class UnwindSectionCompressedArray {
public:
UnwindSectionCompressedArray(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t functionOffset(uint32_t index) const {
return UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(
_addressSpace.get32(_addr + index * sizeof(uint32_t)));
}
uint16_t encodingIndex(uint32_t index) const {
return UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(
_addressSpace.get32(_addr + index * sizeof(uint32_t)));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
template <typename A> class UnwindSectionLsdaArray {
public:
UnwindSectionLsdaArray(A &addressSpace, typename A::pint_t addr)
: _addressSpace(addressSpace), _addr(addr) {}
uint32_t functionOffset(uint32_t index) const {
return _addressSpace.get32(
_addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
index, functionOffset));
}
uint32_t lsdaOffset(uint32_t index) const {
return _addressSpace.get32(
_addr + arrayoffsetof(unwind_info_section_header_lsda_index_entry,
index, lsdaOffset));
}
private:
A &_addressSpace;
typename A::pint_t _addr;
};
#endif // _LIBUNWIND_SUPPORT_COMPACT_UNWIND
class _LIBUNWIND_HIDDEN AbstractUnwindCursor {
public:
// NOTE: provide a class specific placement deallocation function (S5.3.4 p20)
// This avoids an unnecessary dependency to libc++abi.
void operator delete(void *, size_t) {}
virtual ~AbstractUnwindCursor() {}
virtual bool validReg(int) { _LIBUNWIND_ABORT("validReg not implemented"); }
virtual unw_word_t getReg(int) { _LIBUNWIND_ABORT("getReg not implemented"); }
virtual void setReg(int, unw_word_t) {
_LIBUNWIND_ABORT("setReg not implemented");
}
virtual bool validFloatReg(int) {
_LIBUNWIND_ABORT("validFloatReg not implemented");
}
virtual unw_fpreg_t getFloatReg(int) {
_LIBUNWIND_ABORT("getFloatReg not implemented");
}
virtual void setFloatReg(int, unw_fpreg_t) {
_LIBUNWIND_ABORT("setFloatReg not implemented");
}
virtual int step() { _LIBUNWIND_ABORT("step not implemented"); }
virtual void getInfo(unw_proc_info_t *) {
_LIBUNWIND_ABORT("getInfo not implemented");
}
virtual void jumpto() { _LIBUNWIND_ABORT("jumpto not implemented"); }
virtual bool isSignalFrame() {
_LIBUNWIND_ABORT("isSignalFrame not implemented");
}
virtual bool getFunctionName(char *, size_t, unw_word_t *) {
_LIBUNWIND_ABORT("getFunctionName not implemented");
}
virtual void setInfoBasedOnIPRegister(bool = false) {
_LIBUNWIND_ABORT("setInfoBasedOnIPRegister not implemented");
}
virtual const char *getRegisterName(int) {
_LIBUNWIND_ABORT("getRegisterName not implemented");
}
#ifdef __arm__
virtual void saveVFPAsX() { _LIBUNWIND_ABORT("saveVFPAsX not implemented"); }
#endif
};
/// UnwindCursor contains all state (including all register values) during
/// an unwind. This is normally stack allocated inside a unw_cursor_t.
template <typename A, typename R>
class UnwindCursor : public AbstractUnwindCursor{
typedef typename A::pint_t pint_t;
public:
UnwindCursor(unw_context_t *context, A &as);
UnwindCursor(A &as, void *threadArg);
virtual ~UnwindCursor() {}
virtual bool validReg(int);
virtual unw_word_t getReg(int);
virtual void setReg(int, unw_word_t);
virtual bool validFloatReg(int);
virtual unw_fpreg_t getFloatReg(int);
virtual void setFloatReg(int, unw_fpreg_t);
virtual int step();
virtual void getInfo(unw_proc_info_t *);
virtual void jumpto();
virtual bool isSignalFrame();
virtual bool getFunctionName(char *buf, size_t len, unw_word_t *off);
virtual void setInfoBasedOnIPRegister(bool isReturnAddress = false);
virtual const char *getRegisterName(int num);
#ifdef __arm__
virtual void saveVFPAsX();
#endif
private:
#if _LIBUNWIND_ARM_EHABI
bool getInfoFromEHABISection(pint_t pc, const UnwindInfoSections §s);
int stepWithEHABI() {
size_t len = 0;
size_t off = 0;
// FIXME: Calling decode_eht_entry() here is violating the libunwind
// abstraction layer.
const uint32_t *ehtp =
decode_eht_entry(reinterpret_cast<const uint32_t *>(_info.unwind_info),
&off, &len);
if (_Unwind_VRS_Interpret((_Unwind_Context *)this, ehtp, off, len) !=
_URC_CONTINUE_UNWIND)
return UNW_STEP_END;
return UNW_STEP_SUCCESS;
}
#endif
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
bool getInfoFromDwarfSection(pint_t pc, const UnwindInfoSections §s,
uint32_t fdeSectionOffsetHint=0);
int stepWithDwarfFDE() {
return DwarfInstructions<A, R>::stepWithDwarf(_addressSpace,
(pint_t)this->getReg(UNW_REG_IP),
(pint_t)_info.unwind_info,
_registers);
}
#endif
#if _LIBUNWIND_SUPPORT_COMPACT_UNWIND
bool getInfoFromCompactEncodingSection(pint_t pc,
const UnwindInfoSections §s);
int stepWithCompactEncoding() {
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
if ( compactSaysUseDwarf() )
return stepWithDwarfFDE();
#endif
R dummy;
return stepWithCompactEncoding(dummy);
}
int stepWithCompactEncoding(Registers_x86_64 &) {
return CompactUnwinder_x86_64<A>::stepWithCompactEncoding(
_info.format, _info.start_ip, _addressSpace, _registers);
}
int stepWithCompactEncoding(Registers_x86 &) {
return CompactUnwinder_x86<A>::stepWithCompactEncoding(
_info.format, (uint32_t)_info.start_ip, _addressSpace, _registers);
}
int stepWithCompactEncoding(Registers_ppc &) {
return UNW_EINVAL;
}
int stepWithCompactEncoding(Registers_arm64 &) {
return CompactUnwinder_arm64<A>::stepWithCompactEncoding(
_info.format, _info.start_ip, _addressSpace, _registers);
}
bool compactSaysUseDwarf(uint32_t *offset=NULL) const {
R dummy;
return compactSaysUseDwarf(dummy, offset);
}
bool compactSaysUseDwarf(Registers_x86_64 &, uint32_t *offset) const {
if ((_info.format & UNWIND_X86_64_MODE_MASK) == UNWIND_X86_64_MODE_DWARF) {
if (offset)
*offset = (_info.format & UNWIND_X86_64_DWARF_SECTION_OFFSET);
return true;
}
return false;
}
bool compactSaysUseDwarf(Registers_x86 &, uint32_t *offset) const {
if ((_info.format & UNWIND_X86_MODE_MASK) == UNWIND_X86_MODE_DWARF) {
if (offset)
*offset = (_info.format & UNWIND_X86_DWARF_SECTION_OFFSET);
return true;
}
return false;
}
bool compactSaysUseDwarf(Registers_ppc &, uint32_t *) const {
return true;
}
bool compactSaysUseDwarf(Registers_arm64 &, uint32_t *offset) const {
if ((_info.format & UNWIND_ARM64_MODE_MASK) == UNWIND_ARM64_MODE_DWARF) {
if (offset)
*offset = (_info.format & UNWIND_ARM64_DWARF_SECTION_OFFSET);
return true;
}
return false;
}
#endif // _LIBUNWIND_SUPPORT_COMPACT_UNWIND
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
compact_unwind_encoding_t dwarfEncoding() const {
R dummy;
return dwarfEncoding(dummy);
}
compact_unwind_encoding_t dwarfEncoding(Registers_x86_64 &) const {
return UNWIND_X86_64_MODE_DWARF;
}
compact_unwind_encoding_t dwarfEncoding(Registers_x86 &) const {
return UNWIND_X86_MODE_DWARF;
}
compact_unwind_encoding_t dwarfEncoding(Registers_ppc &) const {
return 0;
}
compact_unwind_encoding_t dwarfEncoding(Registers_arm64 &) const {
return UNWIND_ARM64_MODE_DWARF;
}
#endif // _LIBUNWIND_SUPPORT_DWARF_UNWIND
A &_addressSpace;
R _registers;
unw_proc_info_t _info;
bool _unwindInfoMissing;
bool _isSignalFrame;
};
template <typename A, typename R>
UnwindCursor<A, R>::UnwindCursor(unw_context_t *context, A &as)
: _addressSpace(as), _registers(context), _unwindInfoMissing(false),
_isSignalFrame(false) {
static_assert(sizeof(UnwindCursor<A, R>) < sizeof(unw_cursor_t),
"UnwindCursor<> does not fit in unw_cursor_t");
memset(&_info, 0, sizeof(_info));
}
template <typename A, typename R>
UnwindCursor<A, R>::UnwindCursor(A &as, void *)
: _addressSpace(as), _unwindInfoMissing(false), _isSignalFrame(false) {
memset(&_info, 0, sizeof(_info));
// FIXME
// fill in _registers from thread arg
}
template <typename A, typename R>
bool UnwindCursor<A, R>::validReg(int regNum) {
return _registers.validRegister(regNum);
}
template <typename A, typename R>
unw_word_t UnwindCursor<A, R>::getReg(int regNum) {
return _registers.getRegister(regNum);
}
template <typename A, typename R>
void UnwindCursor<A, R>::setReg(int regNum, unw_word_t value) {
_registers.setRegister(regNum, (typename A::pint_t)value);
}
template <typename A, typename R>
bool UnwindCursor<A, R>::validFloatReg(int regNum) {
return _registers.validFloatRegister(regNum);
}
template <typename A, typename R>
unw_fpreg_t UnwindCursor<A, R>::getFloatReg(int regNum) {
return _registers.getFloatRegister(regNum);
}
template <typename A, typename R>
void UnwindCursor<A, R>::setFloatReg(int regNum, unw_fpreg_t value) {
_registers.setFloatRegister(regNum, value);
}
template <typename A, typename R> void UnwindCursor<A, R>::jumpto() {
_registers.jumpto();
}
#ifdef __arm__
template <typename A, typename R> void UnwindCursor<A, R>::saveVFPAsX() {
_registers.saveVFPAsX();
}
#endif
template <typename A, typename R>
const char *UnwindCursor<A, R>::getRegisterName(int regNum) {
return _registers.getRegisterName(regNum);
}
template <typename A, typename R> bool UnwindCursor<A, R>::isSignalFrame() {
return _isSignalFrame;
}
#if _LIBUNWIND_ARM_EHABI
struct EHABIIndexEntry {
uint32_t functionOffset;
uint32_t data;
};
template<typename A>
struct EHABISectionIterator {
typedef EHABISectionIterator _Self;
typedef std::random_access_iterator_tag iterator_category;
typedef typename A::pint_t value_type;
typedef typename A::pint_t* pointer;
typedef typename A::pint_t& reference;
typedef size_t size_type;
typedef size_t difference_type;
static _Self begin(A& addressSpace, const UnwindInfoSections& sects) {
return _Self(addressSpace, sects, 0);
}
static _Self end(A& addressSpace, const UnwindInfoSections& sects) {
return _Self(addressSpace, sects, sects.arm_section_length);
}
EHABISectionIterator(A& addressSpace, const UnwindInfoSections& sects, size_t i)
: _i(i), _addressSpace(&addressSpace), _sects(§s) {}
_Self& operator++() { ++_i; return *this; }
_Self& operator+=(size_t a) { _i += a; return *this; }
_Self& operator--() { assert(_i > 0); --_i; return *this; }
_Self& operator-=(size_t a) { assert(_i >= a); _i -= a; return *this; }
_Self operator+(size_t a) { _Self out = *this; out._i += a; return out; }
_Self operator-(size_t a) { assert(_i >= a); _Self out = *this; out._i -= a; return out; }
size_t operator-(const _Self& other) { return _i - other._i; }
bool operator==(const _Self& other) const {
assert(_addressSpace == other._addressSpace);
assert(_sects == other._sects);
return _i == other._i;
}
typename A::pint_t operator*() const { return functionAddress(); }
typename A::pint_t functionAddress() const {
typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
EHABIIndexEntry, _i, functionOffset);
return indexAddr + signExtendPrel31(_addressSpace->get32(indexAddr));
}
typename A::pint_t dataAddress() {
typename A::pint_t indexAddr = _sects->arm_section + arrayoffsetof(
EHABIIndexEntry, _i, data);
return indexAddr;
}
private:
size_t _i;
A* _addressSpace;
const UnwindInfoSections* _sects;
};
template <typename A, typename R>
bool UnwindCursor<A, R>::getInfoFromEHABISection(
pint_t pc,
const UnwindInfoSections §s) {
EHABISectionIterator<A> begin =
EHABISectionIterator<A>::begin(_addressSpace, sects);
EHABISectionIterator<A> end =
EHABISectionIterator<A>::end(_addressSpace, sects);
EHABISectionIterator<A> itNextPC = std::upper_bound(begin, end, pc);
if (itNextPC == begin || itNextPC == end)
return false;
EHABISectionIterator<A> itThisPC = itNextPC - 1;
pint_t thisPC = itThisPC.functionAddress();
pint_t nextPC = itNextPC.functionAddress();
pint_t indexDataAddr = itThisPC.dataAddress();
if (indexDataAddr == 0)
return false;
uint32_t indexData = _addressSpace.get32(indexDataAddr);
if (indexData == UNW_EXIDX_CANTUNWIND)
return false;
// If the high bit is set, the exception handling table entry is inline inside
// the index table entry on the second word (aka |indexDataAddr|). Otherwise,
// the table points at an offset in the exception handling table (section 5 EHABI).
pint_t exceptionTableAddr;
uint32_t exceptionTableData;
bool isSingleWordEHT;
if (indexData & 0x80000000) {
exceptionTableAddr = indexDataAddr;
// TODO(ajwong): Should this data be 0?
exceptionTableData = indexData;
isSingleWordEHT = true;
} else {
exceptionTableAddr = indexDataAddr + signExtendPrel31(indexData);
exceptionTableData = _addressSpace.get32(exceptionTableAddr);
isSingleWordEHT = false;
}
// Now we know the 3 things:
// exceptionTableAddr -- exception handler table entry.
// exceptionTableData -- the data inside the first word of the eht entry.
// isSingleWordEHT -- whether the entry is in the index.
unw_word_t personalityRoutine = 0xbadf00d;
bool scope32 = false;
uintptr_t lsda;
// If the high bit in the exception handling table entry is set, the entry is
// in compact form (section 6.3 EHABI).
if (exceptionTableData & 0x80000000) {
// Grab the index of the personality routine from the compact form.
uint32_t choice = (exceptionTableData & 0x0f000000) >> 24;
uint32_t extraWords = 0;
switch (choice) {
case 0:
personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr0;
extraWords = 0;
scope32 = false;
lsda = isSingleWordEHT ? 0 : (exceptionTableAddr + 4);
break;
case 1:
personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr1;
extraWords = (exceptionTableData & 0x00ff0000) >> 16;
scope32 = false;
lsda = exceptionTableAddr + (extraWords + 1) * 4;
break;
case 2:
personalityRoutine = (unw_word_t) &__aeabi_unwind_cpp_pr2;
extraWords = (exceptionTableData & 0x00ff0000) >> 16;
scope32 = true;
lsda = exceptionTableAddr + (extraWords + 1) * 4;
break;
default:
_LIBUNWIND_ABORT("unknown personality routine");
return false;
}
if (isSingleWordEHT) {
if (extraWords != 0) {
_LIBUNWIND_ABORT("index inlined table detected but pr function "
"requires extra words");
return false;
}
}
} else {
pint_t personalityAddr =
exceptionTableAddr + signExtendPrel31(exceptionTableData);
personalityRoutine = personalityAddr;
// ARM EHABI # 6.2, # 9.2
//
// +---- ehtp
// v
// +--------------------------------------+
// | +--------+--------+--------+-------+ |
// | |0| prel31 to personalityRoutine | |
// | +--------+--------+--------+-------+ |
// | | N | unwind opcodes | | <-- UnwindData
// | +--------+--------+--------+-------+ |
// | | Word 2 unwind opcodes | |
// | +--------+--------+--------+-------+ |
// | ... |
// | +--------+--------+--------+-------+ |
// | | Word N unwind opcodes | |
// | +--------+--------+--------+-------+ |
// | | LSDA | | <-- lsda
// | | ... | |
// | +--------+--------+--------+-------+ |
// +--------------------------------------+
uint32_t *UnwindData = reinterpret_cast<uint32_t*>(exceptionTableAddr) + 1;
uint32_t FirstDataWord = *UnwindData;
size_t N = ((FirstDataWord >> 24) & 0xff);
size_t NDataWords = N + 1;
lsda = reinterpret_cast<uintptr_t>(UnwindData + NDataWords);
}
_info.start_ip = thisPC;
_info.end_ip = nextPC;
_info.handler = personalityRoutine;
_info.unwind_info = exceptionTableAddr;
_info.lsda = lsda;
// flags is pr_cache.additional. See EHABI #7.2 for definition of bit 0.
_info.flags = isSingleWordEHT ? 1 : 0 | scope32 ? 0x2 : 0; // Use enum?
return true;
}
#endif
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
template <typename A, typename R>
bool UnwindCursor<A, R>::getInfoFromDwarfSection(pint_t pc,
const UnwindInfoSections §s,
uint32_t fdeSectionOffsetHint) {
typename CFI_Parser<A>::FDE_Info fdeInfo;
typename CFI_Parser<A>::CIE_Info cieInfo;
bool foundFDE = false;
bool foundInCache = false;
// If compact encoding table gave offset into dwarf section, go directly there
if (fdeSectionOffsetHint != 0) {
foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
(uint32_t)sects.dwarf_section_length,
sects.dwarf_section + fdeSectionOffsetHint,
&fdeInfo, &cieInfo);
}
#if _LIBUNWIND_SUPPORT_DWARF_INDEX
if (!foundFDE && (sects.dwarf_index_section != 0)) {
foundFDE = EHHeaderParser<A>::findFDE(
_addressSpace, pc, sects.dwarf_index_section,
(uint32_t)sects.dwarf_index_section_length, &fdeInfo, &cieInfo);
}
#endif
if (!foundFDE) {
// otherwise, search cache of previously found FDEs.
pint_t cachedFDE = DwarfFDECache<A>::findFDE(sects.dso_base, pc);
if (cachedFDE != 0) {
foundFDE =
CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
(uint32_t)sects.dwarf_section_length,
cachedFDE, &fdeInfo, &cieInfo);
foundInCache = foundFDE;
}
}
if (!foundFDE) {
// Still not found, do full scan of __eh_frame section.
foundFDE = CFI_Parser<A>::findFDE(_addressSpace, pc, sects.dwarf_section,
(uint32_t)sects.dwarf_section_length, 0,
&fdeInfo, &cieInfo);
}
if (foundFDE) {
typename CFI_Parser<A>::PrologInfo prolog;
if (CFI_Parser<A>::parseFDEInstructions(_addressSpace, fdeInfo, cieInfo, pc,
&prolog)) {
// Save off parsed FDE info
_info.start_ip = fdeInfo.pcStart;
_info.end_ip = fdeInfo.pcEnd;
_info.lsda = fdeInfo.lsda;
_info.handler = cieInfo.personality;
_info.gp = prolog.spExtraArgSize;
_info.flags = 0;
_info.format = dwarfEncoding();
_info.unwind_info = fdeInfo.fdeStart;
_info.unwind_info_size = (uint32_t)fdeInfo.fdeLength;
_info.extra = (unw_word_t) sects.dso_base;
// Add to cache (to make next lookup faster) if we had no hint
// and there was no index.
if (!foundInCache && (fdeSectionOffsetHint == 0)) {
#if _LIBUNWIND_SUPPORT_DWARF_INDEX
if (sects.dwarf_index_section == 0)
#endif
DwarfFDECache<A>::add(sects.dso_base, fdeInfo.pcStart, fdeInfo.pcEnd,
fdeInfo.fdeStart);
}
return true;
}
}
//_LIBUNWIND_DEBUG_LOG("can't find/use FDE for pc=0x%llX\n", (uint64_t)pc);
return false;
}
#endif // _LIBUNWIND_SUPPORT_DWARF_UNWIND
#if _LIBUNWIND_SUPPORT_COMPACT_UNWIND
template <typename A, typename R>
bool UnwindCursor<A, R>::getInfoFromCompactEncodingSection(pint_t pc,
const UnwindInfoSections §s) {
const bool log = false;
if (log)
fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX, mh=0x%llX)\n",
(uint64_t)pc, (uint64_t)sects.dso_base);
const UnwindSectionHeader<A> sectionHeader(_addressSpace,
sects.compact_unwind_section);
if (sectionHeader.version() != UNWIND_SECTION_VERSION)
return false;
// do a binary search of top level index to find page with unwind info
pint_t targetFunctionOffset = pc - sects.dso_base;
const UnwindSectionIndexArray<A> topIndex(_addressSpace,
sects.compact_unwind_section
+ sectionHeader.indexSectionOffset());
uint32_t low = 0;
uint32_t high = sectionHeader.indexCount();
uint32_t last = high - 1;
while (low < high) {
uint32_t mid = (low + high) / 2;
//if ( log ) fprintf(stderr, "\tmid=%d, low=%d, high=%d, *mid=0x%08X\n",
//mid, low, high, topIndex.functionOffset(mid));
if (topIndex.functionOffset(mid) <= targetFunctionOffset) {
if ((mid == last) ||
(topIndex.functionOffset(mid + 1) > targetFunctionOffset)) {
low = mid;
break;
} else {
low = mid + 1;
}
} else {
high = mid;
}
}
const uint32_t firstLevelFunctionOffset = topIndex.functionOffset(low);
const uint32_t firstLevelNextPageFunctionOffset =
topIndex.functionOffset(low + 1);
const pint_t secondLevelAddr =
sects.compact_unwind_section + topIndex.secondLevelPagesSectionOffset(low);
const pint_t lsdaArrayStartAddr =
sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low);
const pint_t lsdaArrayEndAddr =
sects.compact_unwind_section + topIndex.lsdaIndexArraySectionOffset(low+1);
if (log)
fprintf(stderr, "\tfirst level search for result index=%d "
"to secondLevelAddr=0x%llX\n",
low, (uint64_t) secondLevelAddr);
// do a binary search of second level page index
uint32_t encoding = 0;
pint_t funcStart = 0;
pint_t funcEnd = 0;
pint_t lsda = 0;
pint_t personality = 0;
uint32_t pageKind = _addressSpace.get32(secondLevelAddr);
if (pageKind == UNWIND_SECOND_LEVEL_REGULAR) {
// regular page
UnwindSectionRegularPageHeader<A> pageHeader(_addressSpace,
secondLevelAddr);
UnwindSectionRegularArray<A> pageIndex(
_addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
// binary search looks for entry with e where index[e].offset <= pc <
// index[e+1].offset
if (log)
fprintf(stderr, "\tbinary search for targetFunctionOffset=0x%08llX in "
"regular page starting at secondLevelAddr=0x%llX\n",
(uint64_t) targetFunctionOffset, (uint64_t) secondLevelAddr);
low = 0;
high = pageHeader.entryCount();
while (low < high) {
uint32_t mid = (low + high) / 2;
if (pageIndex.functionOffset(mid) <= targetFunctionOffset) {
if (mid == (uint32_t)(pageHeader.entryCount() - 1)) {
// at end of table
low = mid;
funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
break;
} else if (pageIndex.functionOffset(mid + 1) > targetFunctionOffset) {
// next is too big, so we found it
low = mid;
funcEnd = pageIndex.functionOffset(low + 1) + sects.dso_base;
break;
} else {
low = mid + 1;
}
} else {
high = mid;
}
}
encoding = pageIndex.encoding(low);
funcStart = pageIndex.functionOffset(low) + sects.dso_base;
if (pc < funcStart) {
if (log)
fprintf(
stderr,
"\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
(uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
return false;
}
if (pc > funcEnd) {
if (log)
fprintf(
stderr,
"\tpc not in table, pc=0x%llX, funcStart=0x%llX, funcEnd=0x%llX\n",
(uint64_t) pc, (uint64_t) funcStart, (uint64_t) funcEnd);
return false;
}
} else if (pageKind == UNWIND_SECOND_LEVEL_COMPRESSED) {
// compressed page
UnwindSectionCompressedPageHeader<A> pageHeader(_addressSpace,
secondLevelAddr);
UnwindSectionCompressedArray<A> pageIndex(
_addressSpace, secondLevelAddr + pageHeader.entryPageOffset());
const uint32_t targetFunctionPageOffset =
(uint32_t)(targetFunctionOffset - firstLevelFunctionOffset);
// binary search looks for entry with e where index[e].offset <= pc <
// index[e+1].offset
if (log)
fprintf(stderr, "\tbinary search of compressed page starting at "
"secondLevelAddr=0x%llX\n",
(uint64_t) secondLevelAddr);
low = 0;
last = pageHeader.entryCount() - 1;
high = pageHeader.entryCount();
while (low < high) {
uint32_t mid = (low + high) / 2;
if (pageIndex.functionOffset(mid) <= targetFunctionPageOffset) {
if ((mid == last) ||
(pageIndex.functionOffset(mid + 1) > targetFunctionPageOffset)) {
low = mid;
break;
} else {
low = mid + 1;
}
} else {
high = mid;
}
}
funcStart = pageIndex.functionOffset(low) + firstLevelFunctionOffset
+ sects.dso_base;
if (low < last)
funcEnd =
pageIndex.functionOffset(low + 1) + firstLevelFunctionOffset
+ sects.dso_base;
else
funcEnd = firstLevelNextPageFunctionOffset + sects.dso_base;
if (pc < funcStart) {
_LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX not in second "
"level compressed unwind table. funcStart=0x%llX\n",
(uint64_t) pc, (uint64_t) funcStart);
return false;
}
if (pc > funcEnd) {
_LIBUNWIND_DEBUG_LOG("malformed __unwind_info, pc=0x%llX not in second "
"level compressed unwind table. funcEnd=0x%llX\n",
(uint64_t) pc, (uint64_t) funcEnd);
return false;
}
uint16_t encodingIndex = pageIndex.encodingIndex(low);
if (encodingIndex < sectionHeader.commonEncodingsArrayCount()) {
// encoding is in common table in section header
encoding = _addressSpace.get32(
sects.compact_unwind_section +
sectionHeader.commonEncodingsArraySectionOffset() +
encodingIndex * sizeof(uint32_t));
} else {
// encoding is in page specific table
uint16_t pageEncodingIndex =
encodingIndex - (uint16_t)sectionHeader.commonEncodingsArrayCount();
encoding = _addressSpace.get32(secondLevelAddr +
pageHeader.encodingsPageOffset() +
pageEncodingIndex * sizeof(uint32_t));
}
} else {
_LIBUNWIND_DEBUG_LOG("malformed __unwind_info at 0x%0llX bad second "
"level page\n",
(uint64_t) sects.compact_unwind_section);
return false;
}
// look up LSDA, if encoding says function has one
if (encoding & UNWIND_HAS_LSDA) {
UnwindSectionLsdaArray<A> lsdaIndex(_addressSpace, lsdaArrayStartAddr);
uint32_t funcStartOffset = (uint32_t)(funcStart - sects.dso_base);
low = 0;
high = (uint32_t)(lsdaArrayEndAddr - lsdaArrayStartAddr) /
sizeof(unwind_info_section_header_lsda_index_entry);
// binary search looks for entry with exact match for functionOffset
if (log)
fprintf(stderr,
"\tbinary search of lsda table for targetFunctionOffset=0x%08X\n",
funcStartOffset);
while (low < high) {
uint32_t mid = (low + high) / 2;
if (lsdaIndex.functionOffset(mid) == funcStartOffset) {
lsda = lsdaIndex.lsdaOffset(mid) + sects.dso_base;
break;
} else if (lsdaIndex.functionOffset(mid) < funcStartOffset) {
low = mid + 1;
} else {
high = mid;
}
}
if (lsda == 0) {
_LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with HAS_LSDA bit set for "
"pc=0x%0llX, but lsda table has no entry\n",
encoding, (uint64_t) pc);
return false;
}
}
// extact personality routine, if encoding says function has one
uint32_t personalityIndex = (encoding & UNWIND_PERSONALITY_MASK) >>
(__builtin_ctz(UNWIND_PERSONALITY_MASK));
if (personalityIndex != 0) {
--personalityIndex; // change 1-based to zero-based index
if (personalityIndex > sectionHeader.personalityArrayCount()) {
_LIBUNWIND_DEBUG_LOG("found encoding 0x%08X with personality index %d, "
"but personality table has only %d entires\n",
encoding, personalityIndex,
sectionHeader.personalityArrayCount());
return false;
}
int32_t personalityDelta = (int32_t)_addressSpace.get32(
sects.compact_unwind_section +
sectionHeader.personalityArraySectionOffset() +
personalityIndex * sizeof(uint32_t));
pint_t personalityPointer = sects.dso_base + (pint_t)personalityDelta;
personality = _addressSpace.getP(personalityPointer);
if (log)
fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
"personalityDelta=0x%08X, personality=0x%08llX\n",
(uint64_t) pc, personalityDelta, (uint64_t) personality);
}
if (log)
fprintf(stderr, "getInfoFromCompactEncodingSection(pc=0x%llX), "
"encoding=0x%08X, lsda=0x%08llX for funcStart=0x%llX\n",
(uint64_t) pc, encoding, (uint64_t) lsda, (uint64_t) funcStart);
_info.start_ip = funcStart;
_info.end_ip = funcEnd;
_info.lsda = lsda;
_info.handler = personality;
_info.gp = 0;
_info.flags = 0;
_info.format = encoding;
_info.unwind_info = 0;
_info.unwind_info_size = 0;
_info.extra = sects.dso_base;
return true;
}
#endif // _LIBUNWIND_SUPPORT_COMPACT_UNWIND
template <typename A, typename R>
void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
pint_t pc = (pint_t)this->getReg(UNW_REG_IP);
#if _LIBUNWIND_ARM_EHABI
// Remove the thumb bit so the IP represents the actual instruction address.
// This matches the behaviour of _Unwind_GetIP on arm.
pc &= (pint_t)~0x1;
#endif
// If the last line of a function is a "throw" the compiler sometimes
// emits no instructions after the call to __cxa_throw. This means
// the return address is actually the start of the next function.
// To disambiguate this, back up the pc when we know it is a return
// address.
if (isReturnAddress)
--pc;
// Ask address space object to find unwind sections for this pc.
UnwindInfoSections sects;
if (_addressSpace.findUnwindSections(pc, sects)) {
#if _LIBUNWIND_SUPPORT_COMPACT_UNWIND
// If there is a compact unwind encoding table, look there first.
if (sects.compact_unwind_section != 0) {
if (this->getInfoFromCompactEncodingSection(pc, sects)) {
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
// Found info in table, done unless encoding says to use dwarf.
uint32_t dwarfOffset;
if ((sects.dwarf_section != 0) && compactSaysUseDwarf(&dwarfOffset)) {
if (this->getInfoFromDwarfSection(pc, sects, dwarfOffset)) {
// found info in dwarf, done
return;
}
}
#endif
// If unwind table has entry, but entry says there is no unwind info,
// record that we have no unwind info.
if (_info.format == 0)
_unwindInfoMissing = true;
return;
}
}
#endif // _LIBUNWIND_SUPPORT_COMPACT_UNWIND
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
// If there is dwarf unwind info, look there next.
if (sects.dwarf_section != 0) {
if (this->getInfoFromDwarfSection(pc, sects)) {
// found info in dwarf, done
return;
}
}
#endif
#if _LIBUNWIND_ARM_EHABI
// If there is ARM EHABI unwind info, look there next.
if (sects.arm_section != 0 && this->getInfoFromEHABISection(pc, sects))
return;
#endif
}
#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
// There is no static unwind info for this pc. Look to see if an FDE was
// dynamically registered for it.
pint_t cachedFDE = DwarfFDECache<A>::findFDE(0, pc);
if (cachedFDE != 0) {
CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
const char *msg = CFI_Parser<A>::decodeFDE(_addressSpace,
cachedFDE, &fdeInfo, &cieInfo);
if (msg == NULL) {
typename CFI_Parser<A>::PrologInfo prolog;
if (CFI_Parser<A>::parseFDEInstructions(_addressSpace, fdeInfo, cieInfo,
pc, &prolog)) {
// save off parsed FDE info
_info.start_ip = fdeInfo.pcStart;
_info.end_ip = fdeInfo.pcEnd;
_info.lsda = fdeInfo.lsda;
_info.handler = cieInfo.personality;
_info.gp = prolog.spExtraArgSize;
// Some frameless functions need SP
// altered when resuming in function.
_info.flags = 0;
_info.format = dwarfEncoding();
_info.unwind_info = fdeInfo.fdeStart;
_info.unwind_info_size = (uint32_t)fdeInfo.fdeLength;
_info.extra = 0;
return;
}
}
}
// Lastly, ask AddressSpace object about platform specific ways to locate
// other FDEs.
pint_t fde;
if (_addressSpace.findOtherFDE(pc, fde)) {
CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
if (!CFI_Parser<A>::decodeFDE(_addressSpace, fde, &fdeInfo, &cieInfo)) {
// Double check this FDE is for a function that includes the pc.
if ((fdeInfo.pcStart <= pc) && (pc < fdeInfo.pcEnd)) {
typename CFI_Parser<A>::PrologInfo prolog;
if (CFI_Parser<A>::parseFDEInstructions(_addressSpace, fdeInfo,
cieInfo, pc, &prolog)) {
// save off parsed FDE info
_info.start_ip = fdeInfo.pcStart;
_info.end_ip = fdeInfo.pcEnd;
_info.lsda = fdeInfo.lsda;
_info.handler = cieInfo.personality;
_info.gp = prolog.spExtraArgSize;
_info.flags = 0;
_info.format = dwarfEncoding();
_info.unwind_info = fdeInfo.fdeStart;
_info.unwind_info_size = (uint32_t)fdeInfo.fdeLength;
_info.extra = 0;
return;
}
}
}
}
#endif // #if _LIBUNWIND_SUPPORT_DWARF_UNWIND
// no unwind info, flag that we can't reliably unwind
_unwindInfoMissing = true;
}
template <typename A, typename R>
int UnwindCursor<A, R>::step() {
// Bottom of stack is defined is when unwind info cannot be found.
if (_unwindInfoMissing)
return UNW_STEP_END;
// Use unwinding info to modify register set as if function returned.
int result;
#if _LIBUNWIND_SUPPORT_COMPACT_UNWIND
result = this->stepWithCompactEncoding();
#elif _LIBUNWIND_SUPPORT_DWARF_UNWIND
result = this->stepWithDwarfFDE();
#elif _LIBUNWIND_ARM_EHABI
result = this->stepWithEHABI();
#else
#error Need _LIBUNWIND_SUPPORT_COMPACT_UNWIND or \
_LIBUNWIND_SUPPORT_DWARF_UNWIND or \
_LIBUNWIND_ARM_EHABI
#endif
// update info based on new PC
if (result == UNW_STEP_SUCCESS) {
this->setInfoBasedOnIPRegister(true);
if (_unwindInfoMissing)
return UNW_STEP_END;
if (_info.gp)
setReg(UNW_REG_SP, getReg(UNW_REG_SP) + _info.gp);
}
return result;
}
template <typename A, typename R>
void UnwindCursor<A, R>::getInfo(unw_proc_info_t *info) {
*info = _info;
}
template <typename A, typename R>
bool UnwindCursor<A, R>::getFunctionName(char *buf, size_t bufLen,
unw_word_t *offset) {
return _addressSpace.findFunctionName((pint_t)this->getReg(UNW_REG_IP),
buf, bufLen, offset);
}
} // namespace libunwind
#endif // __UNWINDCURSOR_HPP__