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gerrit-public.fairphone.software / platform / art / 66521058c80ee4058995d28f512dd6d173610e3a / . / compiler / elf_writer_debug.cc
blob: 2bc8c89f73693cde74250541c5b26ca917d21512 [file] [log] [blame]
/*
* 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.
*/
#include "elf_writer_debug.h"
#include <unordered_set>
#include <vector>
#include "base/casts.h"
#include "base/stl_util.h"
#include "compiled_method.h"
#include "driver/compiler_driver.h"
#include "dex_file-inl.h"
#include "dwarf/dedup_vector.h"
#include "dwarf/headers.h"
#include "dwarf/method_debug_info.h"
#include "dwarf/register.h"
#include "elf_builder.h"
#include "oat_writer.h"
#include "utils.h"
#include "stack_map.h"
namespace art {
namespace dwarf {
// The ARM specification defines three special mapping symbols
// $a, $t and $d which mark ARM, Thumb and data ranges respectively.
// These symbols can be used by tools, for example, to pretty
// print instructions correctly. Objdump will use them if they
// exist, but it will still work well without them.
// However, these extra symbols take space, so let's just generate
// one symbol which marks the whole .text section as code.
constexpr bool kGenerateSingleArmMappingSymbol = true;
static Reg GetDwarfCoreReg(InstructionSet isa, int machine_reg) {
switch (isa) {
case kArm:
case kThumb2:
return Reg::ArmCore(machine_reg);
case kArm64:
return Reg::Arm64Core(machine_reg);
case kX86:
return Reg::X86Core(machine_reg);
case kX86_64:
return Reg::X86_64Core(machine_reg);
case kMips:
return Reg::MipsCore(machine_reg);
case kMips64:
return Reg::Mips64Core(machine_reg);
default:
LOG(FATAL) << "Unknown instruction set: " << isa;
UNREACHABLE();
}
}
static Reg GetDwarfFpReg(InstructionSet isa, int machine_reg) {
switch (isa) {
case kArm:
case kThumb2:
return Reg::ArmFp(machine_reg);
case kArm64:
return Reg::Arm64Fp(machine_reg);
case kX86:
return Reg::X86Fp(machine_reg);
case kX86_64:
return Reg::X86_64Fp(machine_reg);
default:
LOG(FATAL) << "Unknown instruction set: " << isa;
UNREACHABLE();
}
}
static void WriteCIE(InstructionSet isa,
CFIFormat format,
std::vector<uint8_t>* buffer) {
// Scratch registers should be marked as undefined. This tells the
// debugger that its value in the previous frame is not recoverable.
bool is64bit = Is64BitInstructionSet(isa);
switch (isa) {
case kArm:
case kThumb2: {
DebugFrameOpCodeWriter<> opcodes;
opcodes.DefCFA(Reg::ArmCore(13), 0); // R13(SP).
// core registers.
for (int reg = 0; reg < 13; reg++) {
if (reg < 4 || reg == 12) {
opcodes.Undefined(Reg::ArmCore(reg));
} else {
opcodes.SameValue(Reg::ArmCore(reg));
}
}
// fp registers.
for (int reg = 0; reg < 32; reg++) {
if (reg < 16) {
opcodes.Undefined(Reg::ArmFp(reg));
} else {
opcodes.SameValue(Reg::ArmFp(reg));
}
}
auto return_reg = Reg::ArmCore(14); // R14(LR).
WriteCIE(is64bit, return_reg, opcodes, format, buffer);
return;
}
case kArm64: {
DebugFrameOpCodeWriter<> opcodes;
opcodes.DefCFA(Reg::Arm64Core(31), 0); // R31(SP).
// core registers.
for (int reg = 0; reg < 30; reg++) {
if (reg < 8 || reg == 16 || reg == 17) {
opcodes.Undefined(Reg::Arm64Core(reg));
} else {
opcodes.SameValue(Reg::Arm64Core(reg));
}
}
// fp registers.
for (int reg = 0; reg < 32; reg++) {
if (reg < 8 || reg >= 16) {
opcodes.Undefined(Reg::Arm64Fp(reg));
} else {
opcodes.SameValue(Reg::Arm64Fp(reg));
}
}
auto return_reg = Reg::Arm64Core(30); // R30(LR).
WriteCIE(is64bit, return_reg, opcodes, format, buffer);
return;
}
case kMips:
case kMips64: {
DebugFrameOpCodeWriter<> opcodes;
opcodes.DefCFA(Reg::MipsCore(29), 0); // R29(SP).
// core registers.
for (int reg = 1; reg < 26; reg++) {
if (reg < 16 || reg == 24 || reg == 25) { // AT, V*, A*, T*.
opcodes.Undefined(Reg::MipsCore(reg));
} else {
opcodes.SameValue(Reg::MipsCore(reg));
}
}
auto return_reg = Reg::MipsCore(31); // R31(RA).
WriteCIE(is64bit, return_reg, opcodes, format, buffer);
return;
}
case kX86: {
// FIXME: Add fp registers once libunwind adds support for them. Bug: 20491296
constexpr bool generate_opcodes_for_x86_fp = false;
DebugFrameOpCodeWriter<> opcodes;
opcodes.DefCFA(Reg::X86Core(4), 4); // R4(ESP).
opcodes.Offset(Reg::X86Core(8), -4); // R8(EIP).
// core registers.
for (int reg = 0; reg < 8; reg++) {
if (reg <= 3) {
opcodes.Undefined(Reg::X86Core(reg));
} else if (reg == 4) {
// Stack pointer.
} else {
opcodes.SameValue(Reg::X86Core(reg));
}
}
// fp registers.
if (generate_opcodes_for_x86_fp) {
for (int reg = 0; reg < 8; reg++) {
opcodes.Undefined(Reg::X86Fp(reg));
}
}
auto return_reg = Reg::X86Core(8); // R8(EIP).
WriteCIE(is64bit, return_reg, opcodes, format, buffer);
return;
}
case kX86_64: {
DebugFrameOpCodeWriter<> opcodes;
opcodes.DefCFA(Reg::X86_64Core(4), 8); // R4(RSP).
opcodes.Offset(Reg::X86_64Core(16), -8); // R16(RIP).
// core registers.
for (int reg = 0; reg < 16; reg++) {
if (reg == 4) {
// Stack pointer.
} else if (reg < 12 && reg != 3 && reg != 5) { // except EBX and EBP.
opcodes.Undefined(Reg::X86_64Core(reg));
} else {
opcodes.SameValue(Reg::X86_64Core(reg));
}
}
// fp registers.
for (int reg = 0; reg < 16; reg++) {
if (reg < 12) {
opcodes.Undefined(Reg::X86_64Fp(reg));
} else {
opcodes.SameValue(Reg::X86_64Fp(reg));
}
}
auto return_reg = Reg::X86_64Core(16); // R16(RIP).
WriteCIE(is64bit, return_reg, opcodes, format, buffer);
return;
}
case kNone:
break;
}
LOG(FATAL) << "Can not write CIE frame for ISA " << isa;
UNREACHABLE();
}
template<typename ElfTypes>
void WriteCFISection(ElfBuilder<ElfTypes>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
CFIFormat format) {
CHECK(format == DW_DEBUG_FRAME_FORMAT || format == DW_EH_FRAME_FORMAT);
typedef typename ElfTypes::Addr Elf_Addr;
std::vector<uint32_t> binary_search_table;
std::vector<uintptr_t> patch_locations;
if (format == DW_EH_FRAME_FORMAT) {
binary_search_table.reserve(2 * method_infos.size());
} else {
patch_locations.reserve(method_infos.size());
}
// Write .eh_frame/.debug_frame section.
auto* cfi_section = (format == DW_DEBUG_FRAME_FORMAT
? builder->GetDebugFrame()
: builder->GetEhFrame());
{
cfi_section->Start();
const bool is64bit = Is64BitInstructionSet(builder->GetIsa());
const Elf_Addr text_address = builder->GetText()->GetAddress();
const Elf_Addr cfi_address = cfi_section->GetAddress();
const Elf_Addr cie_address = cfi_address;
Elf_Addr buffer_address = cfi_address;
std::vector<uint8_t> buffer; // Small temporary buffer.
WriteCIE(builder->GetIsa(), format, &buffer);
cfi_section->WriteFully(buffer.data(), buffer.size());
buffer_address += buffer.size();
buffer.clear();
for (const MethodDebugInfo& mi : method_infos) {
if (!mi.deduped_) { // Only one FDE per unique address.
ArrayRef<const uint8_t> opcodes = mi.compiled_method_->GetCFIInfo();
if (!opcodes.empty()) {
const Elf_Addr code_address = text_address + mi.low_pc_;
if (format == DW_EH_FRAME_FORMAT) {
binary_search_table.push_back(
dchecked_integral_cast<uint32_t>(code_address));
binary_search_table.push_back(
dchecked_integral_cast<uint32_t>(buffer_address));
}
WriteFDE(is64bit, cfi_address, cie_address,
code_address, mi.high_pc_ - mi.low_pc_,
opcodes, format, buffer_address, &buffer,
&patch_locations);
cfi_section->WriteFully(buffer.data(), buffer.size());
buffer_address += buffer.size();
buffer.clear();
}
}
}
cfi_section->End();
}
if (format == DW_EH_FRAME_FORMAT) {
auto* header_section = builder->GetEhFrameHdr();
header_section->Start();
uint32_t header_address = dchecked_integral_cast<int32_t>(header_section->GetAddress());
// Write .eh_frame_hdr section.
std::vector<uint8_t> buffer;
Writer<> header(&buffer);
header.PushUint8(1); // Version.
// Encoding of .eh_frame pointer - libunwind does not honor datarel here,
// so we have to use pcrel which means relative to the pointer's location.
header.PushUint8(DW_EH_PE_pcrel | DW_EH_PE_sdata4);
// Encoding of binary search table size.
header.PushUint8(DW_EH_PE_udata4);
// Encoding of binary search table addresses - libunwind supports only this
// specific combination, which means relative to the start of .eh_frame_hdr.
header.PushUint8(DW_EH_PE_datarel | DW_EH_PE_sdata4);
// .eh_frame pointer
header.PushInt32(cfi_section->GetAddress() - (header_address + 4u));
// Binary search table size (number of entries).
header.PushUint32(dchecked_integral_cast<uint32_t>(binary_search_table.size()/2));
header_section->WriteFully(buffer.data(), buffer.size());
// Binary search table.
for (size_t i = 0; i < binary_search_table.size(); i++) {
// Make addresses section-relative since we know the header address now.
binary_search_table[i] -= header_address;
}
header_section->WriteFully(binary_search_table.data(), binary_search_table.size());
header_section->End();
} else {
builder->WritePatches(".debug_frame.oat_patches",
ArrayRef<const uintptr_t>(patch_locations));
}
}
namespace {
struct CompilationUnit {
std::vector<const MethodDebugInfo*> methods_;
size_t debug_line_offset_ = 0;
uint32_t low_pc_ = 0xFFFFFFFFU;
uint32_t high_pc_ = 0;
};
typedef std::vector<DexFile::LocalInfo> LocalInfos;
void LocalInfoCallback(void* ctx, const DexFile::LocalInfo& entry) {
static_cast<LocalInfos*>(ctx)->push_back(entry);
}
typedef std::vector<DexFile::PositionInfo> PositionInfos;
bool PositionInfoCallback(void* ctx, const DexFile::PositionInfo& entry) {
static_cast<PositionInfos*>(ctx)->push_back(entry);
return false;
}
std::vector<const char*> GetParamNames(const MethodDebugInfo* mi) {
std::vector<const char*> names;
if (mi->code_item_ != nullptr) {
const uint8_t* stream = mi->dex_file_->GetDebugInfoStream(mi->code_item_);
if (stream != nullptr) {
DecodeUnsignedLeb128(&stream); // line.
uint32_t parameters_size = DecodeUnsignedLeb128(&stream);
for (uint32_t i = 0; i < parameters_size; ++i) {
uint32_t id = DecodeUnsignedLeb128P1(&stream);
names.push_back(mi->dex_file_->StringDataByIdx(id));
}
}
}
return names;
}
struct VariableLocation {
uint32_t low_pc;
uint32_t high_pc;
DexRegisterLocation reg_lo; // May be None if the location is unknown.
DexRegisterLocation reg_hi; // Most significant bits of 64-bit value.
};
// Get the location of given dex register (e.g. stack or machine register).
// Note that the location might be different based on the current pc.
// The result will cover all ranges where the variable is in scope.
std::vector<VariableLocation> GetVariableLocations(const MethodDebugInfo* method_info,
uint16_t vreg,
bool is64bitValue,
uint32_t dex_pc_low,
uint32_t dex_pc_high) {
std::vector<VariableLocation> variable_locations;
// Get stack maps sorted by pc (they might not be sorted internally).
const CodeInfo code_info(method_info->compiled_method_->GetVmapTable().data());
const StackMapEncoding encoding = code_info.ExtractEncoding();
std::map<uint32_t, StackMap> stack_maps;
for (uint32_t s = 0; s < code_info.GetNumberOfStackMaps(); s++) {
StackMap stack_map = code_info.GetStackMapAt(s, encoding);
DCHECK(stack_map.IsValid());
const uint32_t low_pc = method_info->low_pc_ + stack_map.GetNativePcOffset(encoding);
DCHECK_LE(low_pc, method_info->high_pc_);
stack_maps.emplace(low_pc, stack_map);
}
// Create entries for the requested register based on stack map data.
for (auto it = stack_maps.begin(); it != stack_maps.end(); it++) {
const StackMap& stack_map = it->second;
const uint32_t low_pc = it->first;
auto next_it = it;
next_it++;
const uint32_t high_pc = next_it != stack_maps.end() ? next_it->first
: method_info->high_pc_;
DCHECK_LE(low_pc, high_pc);
if (low_pc == high_pc) {
continue; // Ignore if the address range is empty.
}
// Check that the stack map is in the requested range.
uint32_t dex_pc = stack_map.GetDexPc(encoding);
if (!(dex_pc_low <= dex_pc && dex_pc < dex_pc_high)) {
continue;
}
// Find the location of the dex register.
DexRegisterLocation reg_lo = DexRegisterLocation::None();
DexRegisterLocation reg_hi = DexRegisterLocation::None();
if (stack_map.HasDexRegisterMap(encoding)) {
DexRegisterMap dex_register_map = code_info.GetDexRegisterMapOf(
stack_map, encoding, method_info->code_item_->registers_size_);
reg_lo = dex_register_map.GetDexRegisterLocation(
vreg, method_info->code_item_->registers_size_, code_info, encoding);
if (is64bitValue) {
reg_hi = dex_register_map.GetDexRegisterLocation(
vreg + 1, method_info->code_item_->registers_size_, code_info, encoding);
}
}
// Add location entry for this address range.
if (!variable_locations.empty() &&
variable_locations.back().reg_lo == reg_lo &&
variable_locations.back().reg_hi == reg_hi &&
variable_locations.back().high_pc == low_pc) {
// Merge with the previous entry (extend its range).
variable_locations.back().high_pc = high_pc;
} else {
variable_locations.push_back({low_pc, high_pc, reg_lo, reg_hi});
}
}
return variable_locations;
}
bool IsFromOptimizingCompiler(const MethodDebugInfo* method_info) {
return method_info->compiled_method_->GetQuickCode().size() > 0 &&
method_info->compiled_method_->GetVmapTable().size() > 0 &&
method_info->compiled_method_->GetGcMap().size() == 0 &&
method_info->code_item_ != nullptr;
}
} // namespace
// Helper class to write .debug_info and its supporting sections.
template<typename ElfTypes>
class DebugInfoWriter {
typedef typename ElfTypes::Addr Elf_Addr;
// Helper class to write one compilation unit.
// It holds helper methods and temporary state.
class CompilationUnitWriter {
public:
explicit CompilationUnitWriter(DebugInfoWriter* owner)
: owner_(owner),
info_(Is64BitInstructionSet(owner_->builder_->GetIsa()), &debug_abbrev_) {
}
void Write(const CompilationUnit& compilation_unit) {
CHECK(!compilation_unit.methods_.empty());
const Elf_Addr text_address = owner_->builder_->GetText()->GetAddress();
info_.StartTag(DW_TAG_compile_unit);
info_.WriteStrp(DW_AT_producer, owner_->WriteString("Android dex2oat"));
info_.WriteData1(DW_AT_language, DW_LANG_Java);
info_.WriteStrp(DW_AT_comp_dir, owner_->WriteString("$JAVA_SRC_ROOT"));
info_.WriteAddr(DW_AT_low_pc, text_address + compilation_unit.low_pc_);
info_.WriteUdata(DW_AT_high_pc, compilation_unit.high_pc_ - compilation_unit.low_pc_);
info_.WriteSecOffset(DW_AT_stmt_list, compilation_unit.debug_line_offset_);
const char* last_dex_class_desc = nullptr;
for (auto mi : compilation_unit.methods_) {
const DexFile* dex = mi->dex_file_;
const DexFile::CodeItem* dex_code = mi->code_item_;
const DexFile::MethodId& dex_method = dex->GetMethodId(mi->dex_method_index_);
const DexFile::ProtoId& dex_proto = dex->GetMethodPrototype(dex_method);
const DexFile::TypeList* dex_params = dex->GetProtoParameters(dex_proto);
const char* dex_class_desc = dex->GetMethodDeclaringClassDescriptor(dex_method);
const bool is_static = (mi->access_flags_ & kAccStatic) != 0;
// Enclose the method in correct class definition.
if (last_dex_class_desc != dex_class_desc) {
if (last_dex_class_desc != nullptr) {
EndClassTag(last_dex_class_desc);
}
size_t offset = StartClassTag(dex_class_desc);
type_cache_.emplace(dex_class_desc, offset);
// Check that each class is defined only once.
bool unique = owner_->defined_dex_classes_.insert(dex_class_desc).second;
CHECK(unique) << "Redefinition of " << dex_class_desc;
last_dex_class_desc = dex_class_desc;
}
int start_depth = info_.Depth();
info_.StartTag(DW_TAG_subprogram);
WriteName(dex->GetMethodName(dex_method));
info_.WriteAddr(DW_AT_low_pc, text_address + mi->low_pc_);
info_.WriteUdata(DW_AT_high_pc, mi->high_pc_ - mi->low_pc_);
uint8_t frame_base[] = { DW_OP_call_frame_cfa };
info_.WriteExprLoc(DW_AT_frame_base, &frame_base, sizeof(frame_base));
WriteLazyType(dex->GetReturnTypeDescriptor(dex_proto));
// Write parameters. DecodeDebugLocalInfo returns them as well, but it does not
// guarantee order or uniqueness so it is safer to iterate over them manually.
// DecodeDebugLocalInfo might not also be available if there is no debug info.
std::vector<const char*> param_names = GetParamNames(mi);
uint32_t arg_reg = 0;
if (!is_static) {
info_.StartTag(DW_TAG_formal_parameter);
WriteName("this");
info_.WriteFlag(DW_AT_artificial, true);
WriteLazyType(dex_class_desc);
if (dex_code != nullptr) {
// Write the stack location of the parameter.
const uint32_t vreg = dex_code->registers_size_ - dex_code->ins_size_ + arg_reg;
const bool is64bitValue = false;
WriteRegLocation(mi, vreg, is64bitValue, compilation_unit.low_pc_);
}
arg_reg++;
info_.EndTag();
}
if (dex_params != nullptr) {
for (uint32_t i = 0; i < dex_params->Size(); ++i) {
info_.StartTag(DW_TAG_formal_parameter);
// Parameter names may not be always available.
if (i < param_names.size()) {
WriteName(param_names[i]);
}
// Write the type.
const char* type_desc = dex->StringByTypeIdx(dex_params->GetTypeItem(i).type_idx_);
WriteLazyType(type_desc);
const bool is64bitValue = type_desc[0] == 'D' || type_desc[0] == 'J';
if (dex_code != nullptr) {
// Write the stack location of the parameter.
const uint32_t vreg = dex_code->registers_size_ - dex_code->ins_size_ + arg_reg;
WriteRegLocation(mi, vreg, is64bitValue, compilation_unit.low_pc_);
}
arg_reg += is64bitValue ? 2 : 1;
info_.EndTag();
}
if (dex_code != nullptr) {
DCHECK_EQ(arg_reg, dex_code->ins_size_);
}
}
// Write local variables.
LocalInfos local_infos;
if (dex->DecodeDebugLocalInfo(dex_code,
is_static,
mi->dex_method_index_,
LocalInfoCallback,
&local_infos)) {
for (const DexFile::LocalInfo& var : local_infos) {
if (var.reg_ < dex_code->registers_size_ - dex_code->ins_size_) {
info_.StartTag(DW_TAG_variable);
WriteName(var.name_);
WriteLazyType(var.descriptor_);
bool is64bitValue = var.descriptor_[0] == 'D' || var.descriptor_[0] == 'J';
WriteRegLocation(mi, var.reg_, is64bitValue, compilation_unit.low_pc_,
var.start_address_, var.end_address_);
info_.EndTag();
}
}
}
info_.EndTag();
CHECK_EQ(info_.Depth(), start_depth); // Balanced start/end.
}
if (last_dex_class_desc != nullptr) {
EndClassTag(last_dex_class_desc);
}
CHECK_EQ(info_.Depth(), 1);
FinishLazyTypes();
info_.EndTag(); // DW_TAG_compile_unit
std::vector<uint8_t> buffer;
buffer.reserve(info_.data()->size() + KB);
const size_t offset = owner_->builder_->GetDebugInfo()->GetSize();
const size_t debug_abbrev_offset =
owner_->debug_abbrev_.Insert(debug_abbrev_.data(), debug_abbrev_.size());
WriteDebugInfoCU(debug_abbrev_offset, info_, offset, &buffer, &owner_->debug_info_patches_);
owner_->builder_->GetDebugInfo()->WriteFully(buffer.data(), buffer.size());
}
// Write table into .debug_loc which describes location of dex register.
// The dex register might be valid only at some points and it might
// move between machine registers and stack.
void WriteRegLocation(const MethodDebugInfo* method_info,
uint16_t vreg,
bool is64bitValue,
uint32_t compilation_unit_low_pc,
uint32_t dex_pc_low = 0,
uint32_t dex_pc_high = 0xFFFFFFFF) {
using Kind = DexRegisterLocation::Kind;
if (!IsFromOptimizingCompiler(method_info)) {
return;
}
Writer<> debug_loc(&owner_->debug_loc_);
Writer<> debug_ranges(&owner_->debug_ranges_);
info_.WriteSecOffset(DW_AT_location, debug_loc.size());
info_.WriteSecOffset(DW_AT_start_scope, debug_ranges.size());
std::vector<VariableLocation> variable_locations = GetVariableLocations(
method_info,
vreg,
is64bitValue,
dex_pc_low,
dex_pc_high);
// Write .debug_loc entries.
const InstructionSet isa = owner_->builder_->GetIsa();
const bool is64bit = Is64BitInstructionSet(isa);
for (const VariableLocation& variable_location : variable_locations) {
// Translate dex register location to DWARF expression.
// Note that 64-bit value might be split to two distinct locations.
// (for example, two 32-bit machine registers, or even stack and register)
uint8_t buffer[64];
uint8_t* pos = buffer;
DexRegisterLocation reg_lo = variable_location.reg_lo;
DexRegisterLocation reg_hi = variable_location.reg_hi;
for (int piece = 0; piece < (is64bitValue ? 2 : 1); piece++) {
DexRegisterLocation reg_loc = (piece == 0 ? reg_lo : reg_hi);
const Kind kind = reg_loc.GetKind();
const int32_t value = reg_loc.GetValue();
if (kind == Kind::kInStack) {
const size_t frame_size = method_info->compiled_method_->GetFrameSizeInBytes();
*(pos++) = DW_OP_fbreg;
// The stack offset is relative to SP. Make it relative to CFA.
pos = EncodeSignedLeb128(pos, value - frame_size);
if (piece == 0 && reg_hi.GetKind() == Kind::kInStack &&
reg_hi.GetValue() == value + 4) {
break; // the high word is correctly implied by the low word.
}
} else if (kind == Kind::kInRegister) {
pos = WriteOpReg(pos, GetDwarfCoreReg(isa, value).num());
if (piece == 0 && reg_hi.GetKind() == Kind::kInRegisterHigh &&
reg_hi.GetValue() == value) {
break; // the high word is correctly implied by the low word.
}
} else if (kind == Kind::kInFpuRegister) {
if ((isa == kArm || isa == kThumb2) &&
piece == 0 && reg_hi.GetKind() == Kind::kInFpuRegister &&
reg_hi.GetValue() == value + 1 && value % 2 == 0) {
// Translate S register pair to D register (e.g. S4+S5 to D2).
pos = WriteOpReg(pos, Reg::ArmDp(value / 2).num());
break;
}
if (isa == kMips || isa == kMips64) {
// TODO: Find what the DWARF floating point register numbers are on MIPS.
break;
}
pos = WriteOpReg(pos, GetDwarfFpReg(isa, value).num());
if (piece == 0 && reg_hi.GetKind() == Kind::kInFpuRegisterHigh &&
reg_hi.GetValue() == reg_lo.GetValue()) {
break; // the high word is correctly implied by the low word.
}
} else if (kind == Kind::kConstant) {
*(pos++) = DW_OP_consts;
pos = EncodeSignedLeb128(pos, value);
*(pos++) = DW_OP_stack_value;
} else if (kind == Kind::kNone) {
break;
} else {
// kInStackLargeOffset and kConstantLargeValue are hidden by GetKind().
// kInRegisterHigh and kInFpuRegisterHigh should be handled by
// the special cases above and they should not occur alone.
LOG(ERROR) << "Unexpected register location kind: "
<< DexRegisterLocation::PrettyDescriptor(kind);
break;
}
if (is64bitValue) {
// Write the marker which is needed by split 64-bit values.
// This code is skipped by the special cases.
*(pos++) = DW_OP_piece;
pos = EncodeUnsignedLeb128(pos, 4);
}
}
// Check that the buffer is large enough; keep half of it empty for safety.
DCHECK_LE(static_cast<size_t>(pos - buffer), sizeof(buffer) / 2);
if (pos > buffer) {
if (is64bit) {
debug_loc.PushUint64(variable_location.low_pc - compilation_unit_low_pc);
debug_loc.PushUint64(variable_location.high_pc - compilation_unit_low_pc);
} else {
debug_loc.PushUint32(variable_location.low_pc - compilation_unit_low_pc);
debug_loc.PushUint32(variable_location.high_pc - compilation_unit_low_pc);
}
// Write the expression.
debug_loc.PushUint16(pos - buffer);
debug_loc.PushData(buffer, pos - buffer);
} else {
// Do not generate .debug_loc if the location is not known.
}
}
// Write end-of-list entry.
if (is64bit) {
debug_loc.PushUint64(0);
debug_loc.PushUint64(0);
} else {
debug_loc.PushUint32(0);
debug_loc.PushUint32(0);
}
// Write .debug_ranges entries.
// This includes ranges where the variable is in scope but the location is not known.
for (size_t i = 0; i < variable_locations.size(); i++) {
uint32_t low_pc = variable_locations[i].low_pc;
uint32_t high_pc = variable_locations[i].high_pc;
while (i + 1 < variable_locations.size() && variable_locations[i+1].low_pc == high_pc) {
// Merge address range with the next entry.
high_pc = variable_locations[++i].high_pc;
}
if (is64bit) {
debug_ranges.PushUint64(low_pc - compilation_unit_low_pc);
debug_ranges.PushUint64(high_pc - compilation_unit_low_pc);
} else {
debug_ranges.PushUint32(low_pc - compilation_unit_low_pc);
debug_ranges.PushUint32(high_pc - compilation_unit_low_pc);
}
}
// Write end-of-list entry.
if (is64bit) {
debug_ranges.PushUint64(0);
debug_ranges.PushUint64(0);
} else {
debug_ranges.PushUint32(0);
debug_ranges.PushUint32(0);
}
}
// Some types are difficult to define as we go since they need
// to be enclosed in the right set of namespaces. Therefore we
// just define all types lazily at the end of compilation unit.
void WriteLazyType(const char* type_descriptor) {
if (type_descriptor != nullptr && type_descriptor[0] != 'V') {
lazy_types_.emplace(type_descriptor, info_.size());
info_.WriteRef4(DW_AT_type, 0);
}
}
void FinishLazyTypes() {
for (const auto& lazy_type : lazy_types_) {
info_.UpdateUint32(lazy_type.second, WriteType(lazy_type.first));
}
lazy_types_.clear();
}
private:
void WriteName(const char* name) {
if (name != nullptr) {
info_.WriteStrp(DW_AT_name, owner_->WriteString(name));
}
}
// Helper which writes DWARF expression referencing a register.
static uint8_t* WriteOpReg(uint8_t* buffer, uint32_t dwarf_reg_num) {
if (dwarf_reg_num < 32) {
*(buffer++) = DW_OP_reg0 + dwarf_reg_num;
} else {
*(buffer++) = DW_OP_regx;
buffer = EncodeUnsignedLeb128(buffer, dwarf_reg_num);
}
return buffer;
}
// Convert dex type descriptor to DWARF.
// Returns offset in the compilation unit.
size_t WriteType(const char* desc) {
const auto& it = type_cache_.find(desc);
if (it != type_cache_.end()) {
return it->second;
}
size_t offset;
if (*desc == 'L') {
// Class type. For example: Lpackage/name;
offset = StartClassTag(desc);
info_.WriteFlag(DW_AT_declaration, true);
EndClassTag(desc);
} else if (*desc == '[') {
// Array type.
size_t element_type = WriteType(desc + 1);
offset = info_.StartTag(DW_TAG_array_type);
info_.WriteRef(DW_AT_type, element_type);
info_.EndTag();
} else {
// Primitive types.
const char* name;
uint32_t encoding;
uint32_t byte_size;
switch (*desc) {
case 'B':
name = "byte";
encoding = DW_ATE_signed;
byte_size = 1;
break;
case 'C':
name = "char";
encoding = DW_ATE_UTF;
byte_size = 2;
break;
case 'D':
name = "double";
encoding = DW_ATE_float;
byte_size = 8;
break;
case 'F':
name = "float";
encoding = DW_ATE_float;
byte_size = 4;
break;
case 'I':
name = "int";
encoding = DW_ATE_signed;
byte_size = 4;
break;
case 'J':
name = "long";
encoding = DW_ATE_signed;
byte_size = 8;
break;
case 'S':
name = "short";
encoding = DW_ATE_signed;
byte_size = 2;
break;
case 'Z':
name = "boolean";
encoding = DW_ATE_boolean;
byte_size = 1;
break;
case 'V':
LOG(FATAL) << "Void type should not be encoded";
UNREACHABLE();
default:
LOG(FATAL) << "Unknown dex type descriptor: " << desc;
UNREACHABLE();
}
offset = info_.StartTag(DW_TAG_base_type);
WriteName(name);
info_.WriteData1(DW_AT_encoding, encoding);
info_.WriteData1(DW_AT_byte_size, byte_size);
info_.EndTag();
}
type_cache_.emplace(desc, offset);
return offset;
}
// Start DW_TAG_class_type tag nested in DW_TAG_namespace tags.
// Returns offset of the class tag in the compilation unit.
size_t StartClassTag(const char* desc) {
DCHECK(desc != nullptr && desc[0] == 'L');
// Enclose the type in namespace tags.
const char* end;
for (desc = desc + 1; (end = strchr(desc, '/')) != nullptr; desc = end + 1) {
info_.StartTag(DW_TAG_namespace);
WriteName(std::string(desc, end - desc).c_str());
}
// Start the class tag.
size_t offset = info_.StartTag(DW_TAG_class_type);
end = strchr(desc, ';');
CHECK(end != nullptr);
WriteName(std::string(desc, end - desc).c_str());
return offset;
}
void EndClassTag(const char* desc) {
DCHECK(desc != nullptr && desc[0] == 'L');
// End the class tag.
info_.EndTag();
// Close namespace tags.
const char* end;
for (desc = desc + 1; (end = strchr(desc, '/')) != nullptr; desc = end + 1) {
info_.EndTag();
}
}
// For access to the ELF sections.
DebugInfoWriter<ElfTypes>* owner_;
// Debug abbrevs for this compilation unit only.
std::vector<uint8_t> debug_abbrev_;
// Temporary buffer to create and store the entries.
DebugInfoEntryWriter<> info_;
// Cache of already translated type descriptors.
std::map<const char*, size_t, CStringLess> type_cache_; // type_desc -> definition_offset.
// 32-bit references which need to be resolved to a type later.
std::multimap<const char*, size_t, CStringLess> lazy_types_; // type_desc -> patch_offset.
};
public:
explicit DebugInfoWriter(ElfBuilder<ElfTypes>* builder) : builder_(builder) {
}
void Start() {
builder_->GetDebugInfo()->Start();
}
void WriteCompilationUnit(const CompilationUnit& compilation_unit) {
CompilationUnitWriter writer(this);
writer.Write(compilation_unit);
}
void End() {
builder_->GetDebugInfo()->End();
builder_->WritePatches(".debug_info.oat_patches",
ArrayRef<const uintptr_t>(debug_info_patches_));
builder_->WriteSection(".debug_abbrev", &debug_abbrev_.Data());
builder_->WriteSection(".debug_str", &debug_str_.Data());
builder_->WriteSection(".debug_loc", &debug_loc_);
builder_->WriteSection(".debug_ranges", &debug_ranges_);
}
private:
size_t WriteString(const char* str) {
return debug_str_.Insert(reinterpret_cast<const uint8_t*>(str), strlen(str) + 1);
}
ElfBuilder<ElfTypes>* builder_;
std::vector<uintptr_t> debug_info_patches_;
DedupVector debug_abbrev_;
DedupVector debug_str_;
std::vector<uint8_t> debug_loc_;
std::vector<uint8_t> debug_ranges_;
std::unordered_set<const char*> defined_dex_classes_; // For CHECKs only.
};
template<typename ElfTypes>
class DebugLineWriter {
typedef typename ElfTypes::Addr Elf_Addr;
public:
explicit DebugLineWriter(ElfBuilder<ElfTypes>* builder) : builder_(builder) {
}
void Start() {
builder_->GetDebugLine()->Start();
}
// Write line table for given set of methods.
// Returns the number of bytes written.
size_t WriteCompilationUnit(CompilationUnit& compilation_unit) {
const bool is64bit = Is64BitInstructionSet(builder_->GetIsa());
const Elf_Addr text_address = builder_->GetText()->GetAddress();
compilation_unit.debug_line_offset_ = builder_->GetDebugLine()->GetSize();
std::vector<FileEntry> files;
std::unordered_map<std::string, size_t> files_map;
std::vector<std::string> directories;
std::unordered_map<std::string, size_t> directories_map;
int code_factor_bits_ = 0;
int dwarf_isa = -1;
switch (builder_->GetIsa()) {
case kArm: // arm actually means thumb2.
case kThumb2:
code_factor_bits_ = 1; // 16-bit instuctions
dwarf_isa = 1; // DW_ISA_ARM_thumb.
break;
case kArm64:
case kMips:
case kMips64:
code_factor_bits_ = 2; // 32-bit instructions
break;
case kNone:
case kX86:
case kX86_64:
break;
}
DebugLineOpCodeWriter<> opcodes(is64bit, code_factor_bits_);
for (const MethodDebugInfo* mi : compilation_unit.methods_) {
// Ignore function if we have already generated line table for the same address.
// It would confuse the debugger and the DWARF specification forbids it.
if (mi->deduped_) {
continue;
}
ArrayRef<const SrcMapElem> src_mapping_table;
std::vector<SrcMapElem> src_mapping_table_from_stack_maps;
if (IsFromOptimizingCompiler(mi)) {
// Use stack maps to create mapping table from pc to dex.
const CodeInfo code_info(mi->compiled_method_->GetVmapTable().data());
const StackMapEncoding encoding = code_info.ExtractEncoding();
for (uint32_t s = 0; s < code_info.GetNumberOfStackMaps(); s++) {
StackMap stack_map = code_info.GetStackMapAt(s, encoding);
DCHECK(stack_map.IsValid());
const uint32_t pc = stack_map.GetNativePcOffset(encoding);
const int32_t dex = stack_map.GetDexPc(encoding);
src_mapping_table_from_stack_maps.push_back({pc, dex});
}
std::sort(src_mapping_table_from_stack_maps.begin(),
src_mapping_table_from_stack_maps.end());
src_mapping_table = ArrayRef<const SrcMapElem>(src_mapping_table_from_stack_maps);
} else {
// Use the mapping table provided by the quick compiler.
src_mapping_table = mi->compiled_method_->GetSrcMappingTable();
}
if (src_mapping_table.empty()) {
continue;
}
Elf_Addr method_address = text_address + mi->low_pc_;
PositionInfos position_infos;
const DexFile* dex = mi->dex_file_;
if (!dex->DecodeDebugPositionInfo(mi->code_item_, PositionInfoCallback, &position_infos)) {
continue;
}
if (position_infos.empty()) {
continue;
}
opcodes.SetAddress(method_address);
if (dwarf_isa != -1) {
opcodes.SetISA(dwarf_isa);
}
// Get and deduplicate directory and filename.
int file_index = 0; // 0 - primary source file of the compilation.
auto& dex_class_def = dex->GetClassDef(mi->class_def_index_);
const char* source_file = dex->GetSourceFile(dex_class_def);
if (source_file != nullptr) {
std::string file_name(source_file);
size_t file_name_slash = file_name.find_last_of('/');
std::string class_name(dex->GetClassDescriptor(dex_class_def));
size_t class_name_slash = class_name.find_last_of('/');
std::string full_path(file_name);
// Guess directory from package name.
int directory_index = 0; // 0 - current directory of the compilation.
if (file_name_slash == std::string::npos && // Just filename.
class_name.front() == 'L' && // Type descriptor for a class.
class_name_slash != std::string::npos) { // Has package name.
std::string package_name = class_name.substr(1, class_name_slash - 1);
auto it = directories_map.find(package_name);
if (it == directories_map.end()) {
directory_index = 1 + directories.size();
directories_map.emplace(package_name, directory_index);
directories.push_back(package_name);
} else {
directory_index = it->second;
}
full_path = package_name + "/" + file_name;
}
// Add file entry.
auto it2 = files_map.find(full_path);
if (it2 == files_map.end()) {
file_index = 1 + files.size();
files_map.emplace(full_path, file_index);
files.push_back(FileEntry {
file_name,
directory_index,
0, // Modification time - NA.
0, // File size - NA.
});
} else {
file_index = it2->second;
}
}
opcodes.SetFile(file_index);
// Generate mapping opcodes from PC to Java lines.
if (file_index != 0) {
bool first = true;
for (SrcMapElem pc2dex : src_mapping_table) {
uint32_t pc = pc2dex.from_;
int dex_pc = pc2dex.to_;
// Find mapping with address with is greater than our dex pc; then go back one step.
auto ub = std::upper_bound(position_infos.begin(), position_infos.end(), dex_pc,
[](uint32_t address, const DexFile::PositionInfo& entry) {
return address < entry.address_;
});
if (ub != position_infos.begin()) {
int line = (--ub)->line_;
if (first) {
first = false;
if (pc > 0) {
// Assume that any preceding code is prologue.
int first_line = position_infos.front().line_;
// Prologue is not a sensible place for a breakpoint.
opcodes.NegateStmt();
opcodes.AddRow(method_address, first_line);
opcodes.NegateStmt();
opcodes.SetPrologueEnd();
}
opcodes.AddRow(method_address + pc, line);
} else if (line != opcodes.CurrentLine()) {
opcodes.AddRow(method_address + pc, line);
}
}
}
} else {
// line 0 - instruction cannot be attributed to any source line.
opcodes.AddRow(method_address, 0);
}
opcodes.AdvancePC(text_address + mi->high_pc_);
opcodes.EndSequence();
}
std::vector<uint8_t> buffer;
buffer.reserve(opcodes.data()->size() + KB);
size_t offset = builder_->GetDebugLine()->GetSize();
WriteDebugLineTable(directories, files, opcodes, offset, &buffer, &debug_line_patches);
builder_->GetDebugLine()->WriteFully(buffer.data(), buffer.size());
return buffer.size();
}
void End() {
builder_->GetDebugLine()->End();
builder_->WritePatches(".debug_line.oat_patches",
ArrayRef<const uintptr_t>(debug_line_patches));
}
private:
ElfBuilder<ElfTypes>* builder_;
std::vector<uintptr_t> debug_line_patches;
};
template<typename ElfTypes>
void WriteDebugSections(ElfBuilder<ElfTypes>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos) {
// Group the methods into compilation units based on source file.
std::vector<CompilationUnit> compilation_units;
const char* last_source_file = nullptr;
for (const MethodDebugInfo& mi : method_infos) {
auto& dex_class_def = mi.dex_file_->GetClassDef(mi.class_def_index_);
const char* source_file = mi.dex_file_->GetSourceFile(dex_class_def);
if (compilation_units.empty() || source_file != last_source_file) {
compilation_units.push_back(CompilationUnit());
}
CompilationUnit& cu = compilation_units.back();
cu.methods_.push_back(&mi);
cu.low_pc_ = std::min(cu.low_pc_, mi.low_pc_);
cu.high_pc_ = std::max(cu.high_pc_, mi.high_pc_);
last_source_file = source_file;
}
// Write .debug_line section.
{
DebugLineWriter<ElfTypes> line_writer(builder);
line_writer.Start();
for (auto& compilation_unit : compilation_units) {
line_writer.WriteCompilationUnit(compilation_unit);
}
line_writer.End();
}
// Write .debug_info section.
{
DebugInfoWriter<ElfTypes> info_writer(builder);
info_writer.Start();
for (const auto& compilation_unit : compilation_units) {
info_writer.WriteCompilationUnit(compilation_unit);
}
info_writer.End();
}
}
template <typename ElfTypes>
void WriteDebugSymbols(ElfBuilder<ElfTypes>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos) {
bool generated_mapping_symbol = false;
auto* strtab = builder->GetStrTab();
auto* symtab = builder->GetSymTab();
if (method_infos.empty()) {
return;
}
// Find all addresses (low_pc) which contain deduped methods.
// The first instance of method is not marked deduped_, but the rest is.
std::unordered_set<uint32_t> deduped_addresses;
for (const MethodDebugInfo& info : method_infos) {
if (info.deduped_) {
deduped_addresses.insert(info.low_pc_);
}
}
strtab->Start();
strtab->Write(""); // strtab should start with empty string.
for (const MethodDebugInfo& info : method_infos) {
if (info.deduped_) {
continue; // Add symbol only for the first instance.
}
std::string name = PrettyMethod(info.dex_method_index_, *info.dex_file_, true);
if (deduped_addresses.find(info.low_pc_) != deduped_addresses.end()) {
name += " [DEDUPED]";
}
uint32_t low_pc = info.low_pc_;
// Add in code delta, e.g., thumb bit 0 for Thumb2 code.
low_pc += info.compiled_method_->CodeDelta();
symtab->Add(strtab->Write(name), builder->GetText(), low_pc,
true, info.high_pc_ - info.low_pc_, STB_GLOBAL, STT_FUNC);
// Conforming to aaelf, add $t mapping symbol to indicate start of a sequence of thumb2
// instructions, so that disassembler tools can correctly disassemble.
// Note that even if we generate just a single mapping symbol, ARM's Streamline
// requires it to match function symbol. Just address 0 does not work.
if (info.compiled_method_->GetInstructionSet() == kThumb2) {
if (!generated_mapping_symbol || !kGenerateSingleArmMappingSymbol) {
symtab->Add(strtab->Write("$t"), builder->GetText(), info.low_pc_ & ~1,
true, 0, STB_LOCAL, STT_NOTYPE);
generated_mapping_symbol = true;
}
}
}
strtab->End();
// Symbols are buffered and written after names (because they are smaller).
// We could also do two passes in this function to avoid the buffering.
symtab->Start();
symtab->Write();
symtab->End();
}
template <typename ElfTypes>
void WriteDebugInfo(ElfBuilder<ElfTypes>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
CFIFormat cfi_format) {
if (!method_infos.empty()) {
// Add methods to .symtab.
WriteDebugSymbols(builder, method_infos);
// Generate CFI (stack unwinding information).
WriteCFISection(builder, method_infos, cfi_format);
// Write DWARF .debug_* sections.
WriteDebugSections(builder, method_infos);
}
}
// Explicit instantiations
template void WriteDebugInfo<ElfTypes32>(
ElfBuilder<ElfTypes32>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
CFIFormat cfi_format);
template void WriteDebugInfo<ElfTypes64>(
ElfBuilder<ElfTypes64>* builder,
const ArrayRef<const MethodDebugInfo>& method_infos,
CFIFormat cfi_format);
} // namespace dwarf
} // namespace art