/*
* Copyright (C) 2015 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.
*/
#ifndef ART_COMPILER_DWARF_HEADERS_H_
#define ART_COMPILER_DWARF_HEADERS_H_
#include <cstdint>
#include "dwarf/debug_frame_opcode_writer.h"
#include "dwarf/debug_info_entry_writer.h"
#include "dwarf/debug_line_opcode_writer.h"
#include "dwarf/dwarf_constants.h"
#include "dwarf/register.h"
#include "dwarf/writer.h"
namespace art {
namespace dwarf {
// Note that all headers start with 32-bit length.
// DWARF also supports 64-bit lengths, but we never use that.
// It is intended to support very large debug sections (>4GB),
// and compilers are expected *not* to use it by default.
// In particular, it is not related to machine architecture.
// Write common information entry (CIE) to .debug_frame or .eh_frame section.
template<typename Allocator>
void WriteDebugFrameCIE(bool is64bit,
ExceptionHeaderValueApplication address_type,
Reg return_address_register,
const DebugFrameOpCodeWriter<Allocator>& opcodes,
CFIFormat format,
std::vector<uint8_t>* debug_frame) {
Writer<> writer(debug_frame);
size_t cie_header_start_ = writer.data()->size();
writer.PushUint32(0); // Length placeholder.
writer.PushUint32((format == DW_EH_FRAME_FORMAT) ? 0 : 0xFFFFFFFF); // CIE id.
writer.PushUint8(1); // Version.
writer.PushString("zR");
writer.PushUleb128(DebugFrameOpCodeWriter<Allocator>::kCodeAlignmentFactor);
writer.PushSleb128(DebugFrameOpCodeWriter<Allocator>::kDataAlignmentFactor);
writer.PushUleb128(return_address_register.num()); // ubyte in DWARF2.
writer.PushUleb128(1); // z: Augmentation data size.
if (is64bit) {
if (address_type == DW_EH_PE_pcrel) {
writer.PushUint8(DW_EH_PE_pcrel | DW_EH_PE_sdata8); // R: Pointer encoding.
} else {
DCHECK(address_type == DW_EH_PE_absptr);
writer.PushUint8(DW_EH_PE_absptr | DW_EH_PE_udata8); // R: Pointer encoding.
}
} else {
if (address_type == DW_EH_PE_pcrel) {
writer.PushUint8(DW_EH_PE_pcrel | DW_EH_PE_sdata4); // R: Pointer encoding.
} else {
DCHECK(address_type == DW_EH_PE_absptr);
writer.PushUint8(DW_EH_PE_absptr | DW_EH_PE_udata4); // R: Pointer encoding.
}
}
writer.PushData(opcodes.data());
writer.Pad(is64bit ? 8 : 4);
writer.UpdateUint32(cie_header_start_, writer.data()->size() - cie_header_start_ - 4);
}
// Write frame description entry (FDE) to .debug_frame or .eh_frame section.
template<typename Allocator>
void WriteDebugFrameFDE(bool is64bit, size_t cie_offset,
uint64_t initial_address, uint64_t address_range,
const std::vector<uint8_t, Allocator>* opcodes,
CFIFormat format,
std::vector<uint8_t>* debug_frame,
std::vector<uintptr_t>* debug_frame_patches) {
Writer<> writer(debug_frame);
size_t fde_header_start = writer.data()->size();
writer.PushUint32(0); // Length placeholder.
if (format == DW_EH_FRAME_FORMAT) {
uint32_t cie_pointer = writer.data()->size() - cie_offset;
writer.PushUint32(cie_pointer);
} else {
uint32_t cie_pointer = cie_offset;
writer.PushUint32(cie_pointer);
}
// Relocate initial_address, but not address_range (it is size).
debug_frame_patches->push_back(writer.data()->size());
if (is64bit) {
writer.PushUint64(initial_address);
writer.PushUint64(address_range);
} else {
writer.PushUint32(initial_address);
writer.PushUint32(address_range);
}
writer.PushUleb128(0); // Augmentation data size.
writer.PushData(opcodes);
writer.Pad(is64bit ? 8 : 4);
writer.UpdateUint32(fde_header_start, writer.data()->size() - fde_header_start - 4);
}
// Write compilation unit (CU) to .debug_info section.
template<typename Allocator>
void WriteDebugInfoCU(uint32_t debug_abbrev_offset,
const DebugInfoEntryWriter<Allocator>& entries,
std::vector<uint8_t>* debug_info,
std::vector<uintptr_t>* debug_info_patches) {
Writer<> writer(debug_info);
size_t start = writer.data()->size();
writer.PushUint32(0); // Length placeholder.
writer.PushUint16(3); // Version.
writer.PushUint32(debug_abbrev_offset);
writer.PushUint8(entries.Is64bit() ? 8 : 4);
size_t entries_offset = writer.data()->size();
writer.PushData(entries.data());
writer.UpdateUint32(start, writer.data()->size() - start - 4);
// Copy patch locations and make them relative to .debug_info section.
for (uintptr_t patch_location : entries.GetPatchLocations()) {
debug_info_patches->push_back(entries_offset + patch_location);
}
}
struct FileEntry {
std::string file_name;
int directory_index;
int modification_time;
int file_size;
};
// Write line table to .debug_line section.
template<typename Allocator>
void WriteDebugLineTable(const std::vector<std::string>& include_directories,
const std::vector<FileEntry>& files,
const DebugLineOpCodeWriter<Allocator>& opcodes,
std::vector<uint8_t>* debug_line,
std::vector<uintptr_t>* debug_line_patches) {
Writer<> writer(debug_line);
size_t header_start = writer.data()->size();
writer.PushUint32(0); // Section-length placeholder.
// Claim DWARF-2 version even though we use some DWARF-3 features.
// DWARF-2 consumers will ignore the unknown opcodes.
// This is what clang currently does.
writer.PushUint16(2); // .debug_line version.
size_t header_length_pos = writer.data()->size();
writer.PushUint32(0); // Header-length placeholder.
writer.PushUint8(1 << opcodes.GetCodeFactorBits());
writer.PushUint8(DebugLineOpCodeWriter<Allocator>::kDefaultIsStmt ? 1 : 0);
writer.PushInt8(DebugLineOpCodeWriter<Allocator>::kLineBase);
writer.PushUint8(DebugLineOpCodeWriter<Allocator>::kLineRange);
writer.PushUint8(DebugLineOpCodeWriter<Allocator>::kOpcodeBase);
static const int opcode_lengths[DebugLineOpCodeWriter<Allocator>::kOpcodeBase] = {
0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 };
for (int i = 1; i < DebugLineOpCodeWriter<Allocator>::kOpcodeBase; i++) {
writer.PushUint8(opcode_lengths[i]);
}
for (const std::string& directory : include_directories) {
writer.PushData(directory.data(), directory.size() + 1);
}
writer.PushUint8(0); // Terminate include_directories list.
for (const FileEntry& file : files) {
writer.PushData(file.file_name.data(), file.file_name.size() + 1);
writer.PushUleb128(file.directory_index);
writer.PushUleb128(file.modification_time);
writer.PushUleb128(file.file_size);
}
writer.PushUint8(0); // Terminate file list.
writer.UpdateUint32(header_length_pos, writer.data()->size() - header_length_pos - 4);
size_t opcodes_offset = writer.data()->size();
writer.PushData(opcodes.data());
writer.UpdateUint32(header_start, writer.data()->size() - header_start - 4);
// Copy patch locations and make them relative to .debug_line section.
for (uintptr_t patch_location : opcodes.GetPatchLocations()) {
debug_line_patches->push_back(opcodes_offset + patch_location);
}
}
} // namespace dwarf
} // namespace art
#endif // ART_COMPILER_DWARF_HEADERS_H_