blob: 11806eacefeecb49456afd469dd3df6aa9fa31fa [file] [log] [blame]
/*
* Copyright (C) 2017 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 <assert.h>
#include <stdint.h>
#include <string>
#include "DwarfEncoding.h"
#include "DwarfMemory.h"
#include "Memory.h"
bool DwarfMemory::ReadBytes(void* dst, size_t num_bytes) {
if (!memory_->Read(cur_offset_, dst, num_bytes)) {
return false;
}
cur_offset_ += num_bytes;
return true;
}
template <typename SignedType>
bool DwarfMemory::ReadSigned(uint64_t* value) {
SignedType signed_value;
if (!ReadBytes(&signed_value, sizeof(SignedType))) {
return false;
}
*value = static_cast<int64_t>(signed_value);
return true;
}
bool DwarfMemory::ReadULEB128(uint64_t* value) {
uint64_t cur_value = 0;
uint64_t shift = 0;
uint8_t byte;
do {
if (!ReadBytes(&byte, 1)) {
return false;
}
cur_value += static_cast<uint64_t>(byte & 0x7f) << shift;
shift += 7;
} while (byte & 0x80);
*value = cur_value;
return true;
}
bool DwarfMemory::ReadSLEB128(int64_t* value) {
uint64_t cur_value = 0;
uint64_t shift = 0;
uint8_t byte;
do {
if (!ReadBytes(&byte, 1)) {
return false;
}
cur_value += static_cast<uint64_t>(byte & 0x7f) << shift;
shift += 7;
} while (byte & 0x80);
if (byte & 0x40) {
// Negative value, need to sign extend.
cur_value |= static_cast<uint64_t>(-1) << shift;
}
*value = static_cast<int64_t>(cur_value);
return true;
}
template <typename AddressType>
size_t DwarfMemory::GetEncodedSize(uint8_t encoding) {
switch (encoding & 0x0f) {
case DW_EH_PE_absptr:
return sizeof(AddressType);
case DW_EH_PE_udata1:
case DW_EH_PE_sdata1:
return 1;
case DW_EH_PE_udata2:
case DW_EH_PE_sdata2:
return 2;
case DW_EH_PE_udata4:
case DW_EH_PE_sdata4:
return 4;
case DW_EH_PE_udata8:
case DW_EH_PE_sdata8:
return 8;
case DW_EH_PE_uleb128:
case DW_EH_PE_sleb128:
default:
return 0;
}
}
bool DwarfMemory::AdjustEncodedValue(uint8_t encoding, uint64_t* value) {
assert((encoding & 0x0f) == 0);
assert(encoding != DW_EH_PE_aligned);
// Handle the encoding.
switch (encoding) {
case DW_EH_PE_absptr:
// Nothing to do.
break;
case DW_EH_PE_pcrel:
if (pc_offset_ == static_cast<uint64_t>(-1)) {
// Unsupported encoding.
return false;
}
*value += pc_offset_;
break;
case DW_EH_PE_textrel:
if (text_offset_ == static_cast<uint64_t>(-1)) {
// Unsupported encoding.
return false;
}
*value += text_offset_;
break;
case DW_EH_PE_datarel:
if (data_offset_ == static_cast<uint64_t>(-1)) {
// Unsupported encoding.
return false;
}
*value += data_offset_;
break;
case DW_EH_PE_funcrel:
if (func_offset_ == static_cast<uint64_t>(-1)) {
// Unsupported encoding.
return false;
}
*value += func_offset_;
break;
default:
return false;
}
return true;
}
template <typename AddressType>
bool DwarfMemory::ReadEncodedValue(uint8_t encoding, uint64_t* value) {
if (encoding == DW_EH_PE_omit) {
*value = 0;
return true;
} else if (encoding == DW_EH_PE_aligned) {
if (__builtin_add_overflow(cur_offset_, sizeof(AddressType) - 1, &cur_offset_)) {
return false;
}
cur_offset_ &= -sizeof(AddressType);
if (sizeof(AddressType) != sizeof(uint64_t)) {
*value = 0;
}
return ReadBytes(value, sizeof(AddressType));
}
// Get the data.
switch (encoding & 0x0f) {
case DW_EH_PE_absptr:
if (sizeof(AddressType) != sizeof(uint64_t)) {
*value = 0;
}
if (!ReadBytes(value, sizeof(AddressType))) {
return false;
}
break;
case DW_EH_PE_uleb128:
if (!ReadULEB128(value)) {
return false;
}
break;
case DW_EH_PE_sleb128:
int64_t signed_value;
if (!ReadSLEB128(&signed_value)) {
return false;
}
*value = static_cast<uint64_t>(signed_value);
break;
case DW_EH_PE_udata1: {
uint8_t value8;
if (!ReadBytes(&value8, 1)) {
return false;
}
*value = value8;
} break;
case DW_EH_PE_sdata1:
if (!ReadSigned<int8_t>(value)) {
return false;
}
break;
case DW_EH_PE_udata2: {
uint16_t value16;
if (!ReadBytes(&value16, 2)) {
return false;
}
*value = value16;
} break;
case DW_EH_PE_sdata2:
if (!ReadSigned<int16_t>(value)) {
return false;
}
break;
case DW_EH_PE_udata4: {
uint32_t value32;
if (!ReadBytes(&value32, 4)) {
return false;
}
*value = value32;
} break;
case DW_EH_PE_sdata4:
if (!ReadSigned<int32_t>(value)) {
return false;
}
break;
case DW_EH_PE_udata8:
if (!ReadBytes(value, sizeof(uint64_t))) {
return false;
}
break;
case DW_EH_PE_sdata8:
if (!ReadSigned<int64_t>(value)) {
return false;
}
break;
default:
return false;
}
return AdjustEncodedValue(encoding & 0xf0, value);
}
// Instantiate all of the needed template functions.
template bool DwarfMemory::ReadSigned<int8_t>(uint64_t*);
template bool DwarfMemory::ReadSigned<int16_t>(uint64_t*);
template bool DwarfMemory::ReadSigned<int32_t>(uint64_t*);
template bool DwarfMemory::ReadSigned<int64_t>(uint64_t*);
template size_t DwarfMemory::GetEncodedSize<uint32_t>(uint8_t);
template size_t DwarfMemory::GetEncodedSize<uint64_t>(uint8_t);
template bool DwarfMemory::ReadEncodedValue<uint32_t>(uint8_t, uint64_t*);
template bool DwarfMemory::ReadEncodedValue<uint64_t>(uint8_t, uint64_t*);