compiler/dwarf/headers.h - platform/art - Git at Google

 /*
  * 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_
	/*
	* 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_