blob: 818f5d16a5f62ffc5d63f148978428e3785f34f6 [file] [log] [blame]
/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdint.h>
#include <deque>
#include <string>
#include <android-base/stringprintf.h>
#include <unwindstack/Log.h>
#include <unwindstack/MachineArm.h>
#include <unwindstack/Memory.h>
#include <unwindstack/RegsArm.h>
#include "ArmExidx.h"
#include "Check.h"
namespace unwindstack {
static constexpr uint8_t LOG_CFA_REG = 64;
void ArmExidx::LogRawData() {
std::string log_str("Raw Data:");
for (const uint8_t data : data_) {
log_str += android::base::StringPrintf(" 0x%02x", data);
}
log(log_indent_, log_str.c_str());
}
bool ArmExidx::ExtractEntryData(uint32_t entry_offset) {
data_.clear();
status_ = ARM_STATUS_NONE;
if (entry_offset & 1) {
// The offset needs to be at least two byte aligned.
status_ = ARM_STATUS_INVALID_ALIGNMENT;
return false;
}
// Each entry is a 32 bit prel31 offset followed by 32 bits
// of unwind information. If bit 31 of the unwind data is zero,
// then this is a prel31 offset to the start of the unwind data.
// If the unwind data is 1, then this is a cant unwind entry.
// Otherwise, this data is the compact form of the unwind information.
uint32_t data;
if (!elf_memory_->Read32(entry_offset + 4, &data)) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = entry_offset + 4;
return false;
}
if (data == 1) {
// This is a CANT UNWIND entry.
status_ = ARM_STATUS_NO_UNWIND;
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
log(log_indent_, "Raw Data: 0x00 0x00 0x00 0x01");
}
log(log_indent_, "[cantunwind]");
}
return false;
}
if (data & (1UL << 31)) {
// This is a compact table entry.
if ((data >> 24) & 0xf) {
// This is a non-zero index, this code doesn't support
// other formats.
status_ = ARM_STATUS_INVALID_PERSONALITY;
return false;
}
data_.push_back((data >> 16) & 0xff);
data_.push_back((data >> 8) & 0xff);
uint8_t last_op = data & 0xff;
data_.push_back(last_op);
if (last_op != ARM_OP_FINISH) {
// If this didn't end with a finish op, add one.
data_.push_back(ARM_OP_FINISH);
}
if (log_type_ == ARM_LOG_FULL) {
LogRawData();
}
return true;
}
// Get the address of the ops.
// Sign extend the data value if necessary.
int32_t signed_data = static_cast<int32_t>(data << 1) >> 1;
uint32_t addr = (entry_offset + 4) + signed_data;
if (!elf_memory_->Read32(addr, &data)) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = addr;
return false;
}
size_t num_table_words;
if (data & (1UL << 31)) {
// Compact model.
switch ((data >> 24) & 0xf) {
case 0:
num_table_words = 0;
data_.push_back((data >> 16) & 0xff);
break;
case 1:
case 2:
num_table_words = (data >> 16) & 0xff;
addr += 4;
break;
default:
// Only a personality of 0, 1, 2 is valid.
status_ = ARM_STATUS_INVALID_PERSONALITY;
return false;
}
data_.push_back((data >> 8) & 0xff);
data_.push_back(data & 0xff);
} else {
// Generic model.
// Skip the personality routine data, it doesn't contain any data
// needed to decode the unwind information.
addr += 4;
if (!elf_memory_->Read32(addr, &data)) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = addr;
return false;
}
num_table_words = (data >> 24) & 0xff;
data_.push_back((data >> 16) & 0xff);
data_.push_back((data >> 8) & 0xff);
data_.push_back(data & 0xff);
addr += 4;
}
if (num_table_words > 5) {
status_ = ARM_STATUS_MALFORMED;
return false;
}
for (size_t i = 0; i < num_table_words; i++) {
if (!elf_memory_->Read32(addr, &data)) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = addr;
return false;
}
data_.push_back((data >> 24) & 0xff);
data_.push_back((data >> 16) & 0xff);
data_.push_back((data >> 8) & 0xff);
data_.push_back(data & 0xff);
addr += 4;
}
if (data_.back() != ARM_OP_FINISH) {
// If this didn't end with a finish op, add one.
data_.push_back(ARM_OP_FINISH);
}
if (log_type_ == ARM_LOG_FULL) {
LogRawData();
}
return true;
}
inline bool ArmExidx::GetByte(uint8_t* byte) {
if (data_.empty()) {
status_ = ARM_STATUS_TRUNCATED;
return false;
}
*byte = data_.front();
data_.pop_front();
return true;
}
inline bool ArmExidx::DecodePrefix_10_00(uint8_t byte) {
CHECK((byte >> 4) == 0x8);
uint16_t registers = (byte & 0xf) << 8;
if (!GetByte(&byte)) {
return false;
}
registers |= byte;
if (registers == 0) {
// 10000000 00000000: Refuse to unwind
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Refuse to unwind");
}
status_ = ARM_STATUS_NO_UNWIND;
return false;
}
// 1000iiii iiiiiiii: Pop up to 12 integer registers under masks {r15-r12}, {r11-r4}
registers <<= 4;
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
bool add_comma = false;
std::string msg = "pop {";
for (size_t reg = 4; reg < 16; reg++) {
if (registers & (1 << reg)) {
if (add_comma) {
msg += ", ";
}
msg += android::base::StringPrintf("r%zu", reg);
add_comma = true;
}
}
log(log_indent_, "%s}", msg.c_str());
} else {
uint32_t cfa_offset = __builtin_popcount(registers) * 4;
log_cfa_offset_ += cfa_offset;
for (size_t reg = 4; reg < 16; reg++) {
if (registers & (1 << reg)) {
log_regs_[reg] = cfa_offset;
cfa_offset -= 4;
}
}
}
if (log_skip_execution_) {
return true;
}
}
for (size_t reg = 4; reg < 16; reg++) {
if (registers & (1 << reg)) {
if (!process_memory_->Read32(cfa_, &(*regs_)[reg])) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = cfa_;
return false;
}
cfa_ += 4;
}
}
// If the sp register is modified, change the cfa value.
if (registers & (1 << ARM_REG_SP)) {
cfa_ = (*regs_)[ARM_REG_SP];
}
// Indicate if the pc register was set.
if (registers & (1 << ARM_REG_PC)) {
pc_set_ = true;
}
return true;
}
inline bool ArmExidx::DecodePrefix_10_01(uint8_t byte) {
CHECK((byte >> 4) == 0x9);
uint8_t bits = byte & 0xf;
if (bits == 13 || bits == 15) {
// 10011101: Reserved as prefix for ARM register to register moves
// 10011111: Reserved as prefix for Intel Wireless MMX register to register moves
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "[Reserved]");
}
status_ = ARM_STATUS_RESERVED;
return false;
}
// 1001nnnn: Set vsp = r[nnnn] (nnnn != 13, 15)
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
log(log_indent_, "vsp = r%d", bits);
} else {
log_regs_[LOG_CFA_REG] = bits;
}
if (log_skip_execution_) {
return true;
}
}
// It is impossible for bits to be larger than the total number of
// arm registers, so don't bother checking if bits is a valid register.
cfa_ = (*regs_)[bits];
return true;
}
inline bool ArmExidx::DecodePrefix_10_10(uint8_t byte) {
CHECK((byte >> 4) == 0xa);
// 10100nnn: Pop r4-r[4+nnn]
// 10101nnn: Pop r4-r[4+nnn], r14
if (log_type_ != ARM_LOG_NONE) {
uint8_t end_reg = byte & 0x7;
if (log_type_ == ARM_LOG_FULL) {
std::string msg = "pop {r4";
if (end_reg) {
msg += android::base::StringPrintf("-r%d", 4 + end_reg);
}
if (byte & 0x8) {
log(log_indent_, "%s, r14}", msg.c_str());
} else {
log(log_indent_, "%s}", msg.c_str());
}
} else {
end_reg += 4;
uint32_t cfa_offset = (end_reg - 3) * 4;
if (byte & 0x8) {
cfa_offset += 4;
}
log_cfa_offset_ += cfa_offset;
for (uint8_t reg = 4; reg <= end_reg; reg++) {
log_regs_[reg] = cfa_offset;
cfa_offset -= 4;
}
if (byte & 0x8) {
log_regs_[14] = cfa_offset;
}
}
if (log_skip_execution_) {
return true;
}
}
for (size_t i = 4; i <= 4 + (byte & 0x7); i++) {
if (!process_memory_->Read32(cfa_, &(*regs_)[i])) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = cfa_;
return false;
}
cfa_ += 4;
}
if (byte & 0x8) {
if (!process_memory_->Read32(cfa_, &(*regs_)[ARM_REG_R14])) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = cfa_;
return false;
}
cfa_ += 4;
}
return true;
}
inline bool ArmExidx::DecodePrefix_10_11_0000() {
// 10110000: Finish
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
log(log_indent_, "finish");
}
if (log_skip_execution_) {
status_ = ARM_STATUS_FINISH;
return false;
}
}
status_ = ARM_STATUS_FINISH;
return false;
}
inline bool ArmExidx::DecodePrefix_10_11_0001() {
uint8_t byte;
if (!GetByte(&byte)) {
return false;
}
if (byte == 0) {
// 10110001 00000000: Spare
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
}
if (byte >> 4) {
// 10110001 xxxxyyyy: Spare (xxxx != 0000)
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
}
// 10110001 0000iiii: Pop integer registers under mask {r3, r2, r1, r0}
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
bool add_comma = false;
std::string msg = "pop {";
for (size_t i = 0; i < 4; i++) {
if (byte & (1 << i)) {
if (add_comma) {
msg += ", ";
}
msg += android::base::StringPrintf("r%zu", i);
add_comma = true;
}
}
log(log_indent_, "%s}", msg.c_str());
} else {
byte &= 0xf;
uint32_t cfa_offset = __builtin_popcount(byte) * 4;
log_cfa_offset_ += cfa_offset;
for (size_t reg = 0; reg < 4; reg++) {
if (byte & (1 << reg)) {
log_regs_[reg] = cfa_offset;
cfa_offset -= 4;
}
}
}
if (log_skip_execution_) {
return true;
}
}
for (size_t reg = 0; reg < 4; reg++) {
if (byte & (1 << reg)) {
if (!process_memory_->Read32(cfa_, &(*regs_)[reg])) {
status_ = ARM_STATUS_READ_FAILED;
status_address_ = cfa_;
return false;
}
cfa_ += 4;
}
}
return true;
}
inline void ArmExidx::AdjustRegisters(int32_t offset) {
for (auto& entry : log_regs_) {
if (entry.first >= LOG_CFA_REG) {
break;
}
entry.second += offset;
}
}
inline bool ArmExidx::DecodePrefix_10_11_0010() {
// 10110010 uleb128: vsp = vsp + 0x204 + (uleb128 << 2)
uint32_t result = 0;
uint32_t shift = 0;
uint8_t byte;
do {
if (!GetByte(&byte)) {
return false;
}
result |= (byte & 0x7f) << shift;
shift += 7;
} while (byte & 0x80);
result <<= 2;
if (log_type_ != ARM_LOG_NONE) {
int32_t cfa_offset = 0x204 + result;
if (log_type_ == ARM_LOG_FULL) {
log(log_indent_, "vsp = vsp + %d", cfa_offset);
} else {
log_cfa_offset_ += cfa_offset;
}
AdjustRegisters(cfa_offset);
if (log_skip_execution_) {
return true;
}
}
cfa_ += 0x204 + result;
return true;
}
inline bool ArmExidx::DecodePrefix_10_11_0011() {
// 10110011 sssscccc: Pop VFP double precision registers D[ssss]-D[ssss+cccc] by FSTMFDX
uint8_t byte;
if (!GetByte(&byte)) {
return false;
}
if (log_type_ != ARM_LOG_NONE) {
uint8_t start_reg = byte >> 4;
uint8_t end_reg = start_reg + (byte & 0xf);
if (log_type_ == ARM_LOG_FULL) {
std::string msg = android::base::StringPrintf("pop {d%d", start_reg);
if (end_reg) {
msg += android::base::StringPrintf("-d%d", end_reg);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported DX register display");
}
if (log_skip_execution_) {
return true;
}
}
cfa_ += (byte & 0xf) * 8 + 12;
return true;
}
inline bool ArmExidx::DecodePrefix_10_11_01nn() {
// 101101nn: Spare
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
}
inline bool ArmExidx::DecodePrefix_10_11_1nnn(uint8_t byte) {
CHECK((byte & ~0x07) == 0xb8);
// 10111nnn: Pop VFP double-precision registers D[8]-D[8+nnn] by FSTMFDX
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
uint8_t last_reg = (byte & 0x7);
std::string msg = "pop {d8";
if (last_reg) {
msg += android::base::StringPrintf("-d%d", last_reg + 8);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported DX register display");
}
if (log_skip_execution_) {
return true;
}
}
// Only update the cfa.
cfa_ += (byte & 0x7) * 8 + 12;
return true;
}
inline bool ArmExidx::DecodePrefix_10(uint8_t byte) {
CHECK((byte >> 6) == 0x2);
switch ((byte >> 4) & 0x3) {
case 0:
return DecodePrefix_10_00(byte);
case 1:
return DecodePrefix_10_01(byte);
case 2:
return DecodePrefix_10_10(byte);
default:
switch (byte & 0xf) {
case 0:
return DecodePrefix_10_11_0000();
case 1:
return DecodePrefix_10_11_0001();
case 2:
return DecodePrefix_10_11_0010();
case 3:
return DecodePrefix_10_11_0011();
default:
if (byte & 0x8) {
return DecodePrefix_10_11_1nnn(byte);
} else {
return DecodePrefix_10_11_01nn();
}
}
}
}
inline bool ArmExidx::DecodePrefix_11_000(uint8_t byte) {
CHECK((byte & ~0x07) == 0xc0);
uint8_t bits = byte & 0x7;
if (bits == 6) {
if (!GetByte(&byte)) {
return false;
}
// 11000110 sssscccc: Intel Wireless MMX pop wR[ssss]-wR[ssss+cccc]
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
uint8_t start_reg = byte >> 4;
std::string msg = android::base::StringPrintf("pop {wR%d", start_reg);
uint8_t end_reg = byte & 0xf;
if (end_reg) {
msg += android::base::StringPrintf("-wR%d", start_reg + end_reg);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported wRX register display");
}
if (log_skip_execution_) {
return true;
}
}
// Only update the cfa.
cfa_ += (byte & 0xf) * 8 + 8;
} else if (bits == 7) {
if (!GetByte(&byte)) {
return false;
}
if (byte == 0) {
// 11000111 00000000: Spare
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
} else if ((byte >> 4) == 0) {
// 11000111 0000iiii: Intel Wireless MMX pop wCGR registers {wCGR0,1,2,3}
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
bool add_comma = false;
std::string msg = "pop {";
for (size_t i = 0; i < 4; i++) {
if (byte & (1 << i)) {
if (add_comma) {
msg += ", ";
}
msg += android::base::StringPrintf("wCGR%zu", i);
add_comma = true;
}
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported wCGR register display");
}
if (log_skip_execution_) {
return true;
}
}
// Only update the cfa.
cfa_ += __builtin_popcount(byte) * 4;
} else {
// 11000111 xxxxyyyy: Spare (xxxx != 0000)
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
}
} else {
// 11000nnn: Intel Wireless MMX pop wR[10]-wR[10+nnn] (nnn != 6, 7)
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
std::string msg = "pop {wR10";
uint8_t nnn = byte & 0x7;
if (nnn) {
msg += android::base::StringPrintf("-wR%d", 10 + nnn);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported wRX register display");
}
if (log_skip_execution_) {
return true;
}
}
// Only update the cfa.
cfa_ += (byte & 0x7) * 8 + 8;
}
return true;
}
inline bool ArmExidx::DecodePrefix_11_001(uint8_t byte) {
CHECK((byte & ~0x07) == 0xc8);
uint8_t bits = byte & 0x7;
if (bits == 0) {
// 11001000 sssscccc: Pop VFP double precision registers D[16+ssss]-D[16+ssss+cccc] by VPUSH
if (!GetByte(&byte)) {
return false;
}
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
uint8_t start_reg = byte >> 4;
std::string msg = android::base::StringPrintf("pop {d%d", 16 + start_reg);
uint8_t end_reg = byte & 0xf;
if (end_reg) {
msg += android::base::StringPrintf("-d%d", 16 + start_reg + end_reg);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported DX register display");
}
if (log_skip_execution_) {
return true;
}
}
// Only update the cfa.
cfa_ += (byte & 0xf) * 8 + 8;
} else if (bits == 1) {
// 11001001 sssscccc: Pop VFP double precision registers D[ssss]-D[ssss+cccc] by VPUSH
if (!GetByte(&byte)) {
return false;
}
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
uint8_t start_reg = byte >> 4;
std::string msg = android::base::StringPrintf("pop {d%d", start_reg);
uint8_t end_reg = byte & 0xf;
if (end_reg) {
msg += android::base::StringPrintf("-d%d", start_reg + end_reg);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported DX register display");
}
if (log_skip_execution_) {
return true;
}
}
// Only update the cfa.
cfa_ += (byte & 0xf) * 8 + 8;
} else {
// 11001yyy: Spare (yyy != 000, 001)
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
}
return true;
}
inline bool ArmExidx::DecodePrefix_11_010(uint8_t byte) {
CHECK((byte & ~0x07) == 0xd0);
// 11010nnn: Pop VFP double precision registers D[8]-D[8+nnn] by VPUSH
if (log_type_ != ARM_LOG_NONE) {
if (log_type_ == ARM_LOG_FULL) {
std::string msg = "pop {d8";
uint8_t end_reg = byte & 0x7;
if (end_reg) {
msg += android::base::StringPrintf("-d%d", 8 + end_reg);
}
log(log_indent_, "%s}", msg.c_str());
} else {
log(log_indent_, "Unsupported DX register display");
}
if (log_skip_execution_) {
return true;
}
}
cfa_ += (byte & 0x7) * 8 + 8;
return true;
}
inline bool ArmExidx::DecodePrefix_11(uint8_t byte) {
CHECK((byte >> 6) == 0x3);
switch ((byte >> 3) & 0x7) {
case 0:
return DecodePrefix_11_000(byte);
case 1:
return DecodePrefix_11_001(byte);
case 2:
return DecodePrefix_11_010(byte);
default:
// 11xxxyyy: Spare (xxx != 000, 001, 010)
if (log_type_ != ARM_LOG_NONE) {
log(log_indent_, "Spare");
}
status_ = ARM_STATUS_SPARE;
return false;
}
}
bool ArmExidx::Decode() {
status_ = ARM_STATUS_NONE;
uint8_t byte;
if (!GetByte(&byte)) {
return false;
}
switch (byte >> 6) {
case 0:
// 00xxxxxx: vsp = vsp + (xxxxxxx << 2) + 4
if (log_type_ != ARM_LOG_NONE) {
int32_t cfa_offset = ((byte & 0x3f) << 2) + 4;
if (log_type_ == ARM_LOG_FULL) {
log(log_indent_, "vsp = vsp + %d", cfa_offset);
} else {
log_cfa_offset_ += cfa_offset;
}
AdjustRegisters(cfa_offset);
if (log_skip_execution_) {
break;
}
}
cfa_ += ((byte & 0x3f) << 2) + 4;
break;
case 1:
// 01xxxxxx: vsp = vsp - (xxxxxxx << 2) + 4
if (log_type_ != ARM_LOG_NONE) {
uint32_t cfa_offset = ((byte & 0x3f) << 2) + 4;
if (log_type_ == ARM_LOG_FULL) {
log(log_indent_, "vsp = vsp - %d", cfa_offset);
} else {
log_cfa_offset_ -= cfa_offset;
}
AdjustRegisters(-cfa_offset);
if (log_skip_execution_) {
break;
}
}
cfa_ -= ((byte & 0x3f) << 2) + 4;
break;
case 2:
return DecodePrefix_10(byte);
default:
return DecodePrefix_11(byte);
}
return true;
}
bool ArmExidx::Eval() {
pc_set_ = false;
while (Decode());
return status_ == ARM_STATUS_FINISH;
}
void ArmExidx::LogByReg() {
if (log_type_ != ARM_LOG_BY_REG) {
return;
}
uint8_t cfa_reg;
if (log_regs_.count(LOG_CFA_REG) == 0) {
cfa_reg = 13;
} else {
cfa_reg = log_regs_[LOG_CFA_REG];
}
if (log_cfa_offset_ != 0) {
char sign = (log_cfa_offset_ > 0) ? '+' : '-';
log(log_indent_, "cfa = r%zu %c %d", cfa_reg, sign, abs(log_cfa_offset_));
} else {
log(log_indent_, "cfa = r%zu", cfa_reg);
}
for (const auto& entry : log_regs_) {
if (entry.first >= LOG_CFA_REG) {
break;
}
if (entry.second == 0) {
log(log_indent_, "r%zu = [cfa]", entry.first);
} else {
char sign = (entry.second > 0) ? '-' : '+';
log(log_indent_, "r%zu = [cfa %c %d]", entry.first, sign, abs(entry.second));
}
}
}
} // namespace unwindstack