forked from WebAssembly/binaryen
/
DWARFDebugLine.cpp
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/
DWARFDebugLine.cpp
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//===- DWARFDebugLine.cpp -------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <cstdint>
#include <cstdio>
#include <utility>
using namespace llvm;
using namespace dwarf;
using FileLineInfoKind = DILineInfoSpecifier::FileLineInfoKind;
namespace {
struct ContentDescriptor {
dwarf::LineNumberEntryFormat Type;
dwarf::Form Form;
};
using ContentDescriptors = SmallVector<ContentDescriptor, 4>;
} // end anonmyous namespace
void DWARFDebugLine::ContentTypeTracker::trackContentType(
dwarf::LineNumberEntryFormat ContentType) {
switch (ContentType) {
case dwarf::DW_LNCT_timestamp:
HasModTime = true;
break;
case dwarf::DW_LNCT_size:
HasLength = true;
break;
case dwarf::DW_LNCT_MD5:
HasMD5 = true;
break;
case dwarf::DW_LNCT_LLVM_source:
HasSource = true;
break;
default:
// We only care about values we consider optional, and new values may be
// added in the vendor extension range, so we do not match exhaustively.
break;
}
}
DWARFDebugLine::Prologue::Prologue() { clear(); }
bool DWARFDebugLine::Prologue::hasFileAtIndex(uint64_t FileIndex) const {
uint16_t DwarfVersion = getVersion();
assert(DwarfVersion != 0 &&
"line table prologue has no dwarf version information");
if (DwarfVersion >= 5)
return FileIndex < FileNames.size();
return FileIndex != 0 && FileIndex <= FileNames.size();
}
const llvm::DWARFDebugLine::FileNameEntry &
DWARFDebugLine::Prologue::getFileNameEntry(uint64_t Index) const {
uint16_t DwarfVersion = getVersion();
assert(DwarfVersion != 0 &&
"line table prologue has no dwarf version information");
// In DWARF v5 the file names are 0-indexed.
if (DwarfVersion >= 5)
return FileNames[Index];
return FileNames[Index - 1];
}
void DWARFDebugLine::Prologue::clear() {
TotalLength = PrologueLength = 0;
SegSelectorSize = 0;
MinInstLength = MaxOpsPerInst = DefaultIsStmt = LineBase = LineRange = 0;
OpcodeBase = 0;
FormParams = dwarf::FormParams({0, 0, DWARF32});
ContentTypes = ContentTypeTracker();
StandardOpcodeLengths.clear();
IncludeDirectories.clear();
FileNames.clear();
}
void DWARFDebugLine::Prologue::dump(raw_ostream &OS,
DIDumpOptions DumpOptions) const {
OS << "Line table prologue:\n"
<< format(" total_length: 0x%8.8" PRIx64 "\n", TotalLength)
<< format(" version: %u\n", getVersion());
if (getVersion() >= 5)
OS << format(" address_size: %u\n", getAddressSize())
<< format(" seg_select_size: %u\n", SegSelectorSize);
OS << format(" prologue_length: 0x%8.8" PRIx64 "\n", PrologueLength)
<< format(" min_inst_length: %u\n", MinInstLength)
<< format(getVersion() >= 4 ? "max_ops_per_inst: %u\n" : "", MaxOpsPerInst)
<< format(" default_is_stmt: %u\n", DefaultIsStmt)
<< format(" line_base: %i\n", LineBase)
<< format(" line_range: %u\n", LineRange)
<< format(" opcode_base: %u\n", OpcodeBase);
for (uint32_t I = 0; I != StandardOpcodeLengths.size(); ++I)
OS << format("standard_opcode_lengths[%s] = %u\n",
LNStandardString(I + 1).data(), StandardOpcodeLengths[I]);
if (!IncludeDirectories.empty()) {
// DWARF v5 starts directory indexes at 0.
uint32_t DirBase = getVersion() >= 5 ? 0 : 1;
for (uint32_t I = 0; I != IncludeDirectories.size(); ++I) {
OS << format("include_directories[%3u] = ", I + DirBase);
IncludeDirectories[I].dump(OS, DumpOptions);
OS << '\n';
}
}
if (!FileNames.empty()) {
// DWARF v5 starts file indexes at 0.
uint32_t FileBase = getVersion() >= 5 ? 0 : 1;
for (uint32_t I = 0; I != FileNames.size(); ++I) {
const FileNameEntry &FileEntry = FileNames[I];
OS << format("file_names[%3u]:\n", I + FileBase);
OS << " name: ";
FileEntry.Name.dump(OS, DumpOptions);
OS << '\n'
<< format(" dir_index: %" PRIu64 "\n", FileEntry.DirIdx);
if (ContentTypes.HasMD5)
OS << " md5_checksum: " << FileEntry.Checksum.digest() << '\n';
if (ContentTypes.HasModTime)
OS << format(" mod_time: 0x%8.8" PRIx64 "\n", FileEntry.ModTime);
if (ContentTypes.HasLength)
OS << format(" length: 0x%8.8" PRIx64 "\n", FileEntry.Length);
if (ContentTypes.HasSource) {
OS << " source: ";
FileEntry.Source.dump(OS, DumpOptions);
OS << '\n';
}
}
}
}
// Parse v2-v4 directory and file tables.
static void
parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
uint64_t *OffsetPtr, uint64_t EndPrologueOffset,
DWARFDebugLine::ContentTypeTracker &ContentTypes,
std::vector<DWARFFormValue> &IncludeDirectories,
std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
while (*OffsetPtr < EndPrologueOffset) {
StringRef S = DebugLineData.getCStrRef(OffsetPtr);
if (S.empty())
break;
DWARFFormValue Dir =
DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, S.data());
IncludeDirectories.push_back(Dir);
}
while (*OffsetPtr < EndPrologueOffset) {
StringRef Name = DebugLineData.getCStrRef(OffsetPtr);
if (Name.empty())
break;
DWARFDebugLine::FileNameEntry FileEntry;
FileEntry.Name =
DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name.data());
FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
FileNames.push_back(FileEntry);
}
ContentTypes.HasModTime = true;
ContentTypes.HasLength = true;
}
// Parse v5 directory/file entry content descriptions.
// Returns the descriptors, or an error if we did not find a path or ran off
// the end of the prologue.
static llvm::Expected<ContentDescriptors>
parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
uint64_t EndPrologueOffset,
DWARFDebugLine::ContentTypeTracker *ContentTypes) {
ContentDescriptors Descriptors;
int FormatCount = DebugLineData.getU8(OffsetPtr);
bool HasPath = false;
for (int I = 0; I != FormatCount; ++I) {
if (*OffsetPtr >= EndPrologueOffset)
return createStringError(
errc::invalid_argument,
"failed to parse entry content descriptions at offset "
"0x%8.8" PRIx64
" because offset extends beyond the prologue end at offset "
"0x%8.8" PRIx64,
*OffsetPtr, EndPrologueOffset);
ContentDescriptor Descriptor;
Descriptor.Type =
dwarf::LineNumberEntryFormat(DebugLineData.getULEB128(OffsetPtr));
Descriptor.Form = dwarf::Form(DebugLineData.getULEB128(OffsetPtr));
if (Descriptor.Type == dwarf::DW_LNCT_path)
HasPath = true;
if (ContentTypes)
ContentTypes->trackContentType(Descriptor.Type);
Descriptors.push_back(Descriptor);
}
if (!HasPath)
return createStringError(errc::invalid_argument,
"failed to parse entry content descriptions"
" because no path was found");
return Descriptors;
}
static Error
parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
uint64_t *OffsetPtr, uint64_t EndPrologueOffset,
const dwarf::FormParams &FormParams,
const DWARFContext &Ctx, const DWARFUnit *U,
DWARFDebugLine::ContentTypeTracker &ContentTypes,
std::vector<DWARFFormValue> &IncludeDirectories,
std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
// Get the directory entry description.
llvm::Expected<ContentDescriptors> DirDescriptors =
parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset, nullptr);
if (!DirDescriptors)
return DirDescriptors.takeError();
// Get the directory entries, according to the format described above.
int DirEntryCount = DebugLineData.getU8(OffsetPtr);
for (int I = 0; I != DirEntryCount; ++I) {
if (*OffsetPtr >= EndPrologueOffset)
return createStringError(
errc::invalid_argument,
"failed to parse directory entry at offset "
"0x%8.8" PRIx64
" because offset extends beyond the prologue end at offset "
"0x%8.8" PRIx64,
*OffsetPtr, EndPrologueOffset);
for (auto Descriptor : *DirDescriptors) {
DWARFFormValue Value(Descriptor.Form);
switch (Descriptor.Type) {
case DW_LNCT_path:
if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
return createStringError(errc::invalid_argument,
"failed to parse directory entry because "
"extracting the form value failed.");
IncludeDirectories.push_back(Value);
break;
default:
if (!Value.skipValue(DebugLineData, OffsetPtr, FormParams))
return createStringError(errc::invalid_argument,
"failed to parse directory entry because "
"skipping the form value failed.");
}
}
}
// Get the file entry description.
llvm::Expected<ContentDescriptors> FileDescriptors = parseV5EntryFormat(
DebugLineData, OffsetPtr, EndPrologueOffset, &ContentTypes);
if (!FileDescriptors)
return FileDescriptors.takeError();
// Get the file entries, according to the format described above.
int FileEntryCount = DebugLineData.getU8(OffsetPtr);
for (int I = 0; I != FileEntryCount; ++I) {
if (*OffsetPtr >= EndPrologueOffset)
return createStringError(
errc::invalid_argument,
"failed to parse file entry at offset "
"0x%8.8" PRIx64
" because offset extends beyond the prologue end at offset "
"0x%8.8" PRIx64,
*OffsetPtr, EndPrologueOffset);
DWARFDebugLine::FileNameEntry FileEntry;
for (auto Descriptor : *FileDescriptors) {
DWARFFormValue Value(Descriptor.Form);
if (!Value.extractValue(DebugLineData, OffsetPtr, FormParams, &Ctx, U))
return createStringError(errc::invalid_argument,
"failed to parse file entry because "
"extracting the form value failed.");
switch (Descriptor.Type) {
case DW_LNCT_path:
FileEntry.Name = Value;
break;
case DW_LNCT_LLVM_source:
FileEntry.Source = Value;
break;
case DW_LNCT_directory_index:
FileEntry.DirIdx = Value.getAsUnsignedConstant().getValue();
break;
case DW_LNCT_timestamp:
FileEntry.ModTime = Value.getAsUnsignedConstant().getValue();
break;
case DW_LNCT_size:
FileEntry.Length = Value.getAsUnsignedConstant().getValue();
break;
case DW_LNCT_MD5:
if (!Value.getAsBlock() || Value.getAsBlock().getValue().size() != 16)
return createStringError(
errc::invalid_argument,
"failed to parse file entry because the MD5 hash is invalid");
std::uninitialized_copy_n(Value.getAsBlock().getValue().begin(), 16,
FileEntry.Checksum.Bytes.begin());
break;
default:
break;
}
}
FileNames.push_back(FileEntry);
}
return Error::success();
}
Error DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
uint64_t *OffsetPtr,
const DWARFContext &Ctx,
const DWARFUnit *U) {
const uint64_t PrologueOffset = *OffsetPtr;
clear();
TotalLength = DebugLineData.getRelocatedValue(4, OffsetPtr);
if (TotalLength == dwarf::DW_LENGTH_DWARF64) {
FormParams.Format = dwarf::DWARF64;
TotalLength = DebugLineData.getU64(OffsetPtr);
} else if (TotalLength >= dwarf::DW_LENGTH_lo_reserved) {
return createStringError(errc::invalid_argument,
"parsing line table prologue at offset 0x%8.8" PRIx64
" unsupported reserved unit length found of value 0x%8.8" PRIx64,
PrologueOffset, TotalLength);
}
FormParams.Version = DebugLineData.getU16(OffsetPtr);
if (getVersion() < 2)
return createStringError(errc::not_supported,
"parsing line table prologue at offset 0x%8.8" PRIx64
" found unsupported version 0x%2.2" PRIx16,
PrologueOffset, getVersion());
if (getVersion() >= 5) {
FormParams.AddrSize = DebugLineData.getU8(OffsetPtr);
assert((DebugLineData.getAddressSize() == 0 ||
DebugLineData.getAddressSize() == getAddressSize()) &&
"Line table header and data extractor disagree");
SegSelectorSize = DebugLineData.getU8(OffsetPtr);
}
PrologueLength =
DebugLineData.getRelocatedValue(sizeofPrologueLength(), OffsetPtr);
const uint64_t EndPrologueOffset = PrologueLength + *OffsetPtr;
MinInstLength = DebugLineData.getU8(OffsetPtr);
if (getVersion() >= 4)
MaxOpsPerInst = DebugLineData.getU8(OffsetPtr);
DefaultIsStmt = DebugLineData.getU8(OffsetPtr);
LineBase = DebugLineData.getU8(OffsetPtr);
LineRange = DebugLineData.getU8(OffsetPtr);
OpcodeBase = DebugLineData.getU8(OffsetPtr);
StandardOpcodeLengths.reserve(OpcodeBase - 1);
for (uint32_t I = 1; I < OpcodeBase; ++I) {
uint8_t OpLen = DebugLineData.getU8(OffsetPtr);
StandardOpcodeLengths.push_back(OpLen);
}
if (getVersion() >= 5) {
if (Error e = parseV5DirFileTables(
DebugLineData, OffsetPtr, EndPrologueOffset, FormParams, Ctx, U,
ContentTypes, IncludeDirectories, FileNames)) {
return joinErrors(
createStringError(
errc::invalid_argument,
"parsing line table prologue at 0x%8.8" PRIx64
" found an invalid directory or file table description at"
" 0x%8.8" PRIx64,
PrologueOffset, *OffsetPtr),
std::move(e));
}
} else
parseV2DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
ContentTypes, IncludeDirectories, FileNames);
if (*OffsetPtr != EndPrologueOffset)
return createStringError(errc::invalid_argument,
"parsing line table prologue at 0x%8.8" PRIx64
" should have ended at 0x%8.8" PRIx64
" but it ended at 0x%8.8" PRIx64,
PrologueOffset, EndPrologueOffset, *OffsetPtr);
return Error::success();
}
DWARFDebugLine::Row::Row(bool DefaultIsStmt) { reset(DefaultIsStmt); }
void DWARFDebugLine::Row::postAppend() {
Discriminator = 0;
BasicBlock = false;
PrologueEnd = false;
EpilogueBegin = false;
}
void DWARFDebugLine::Row::reset(bool DefaultIsStmt) {
Address.Address = 0;
Address.SectionIndex = object::SectionedAddress::UndefSection;
Line = 1;
Column = 0;
File = 1;
Isa = 0;
Discriminator = 0;
IsStmt = DefaultIsStmt;
BasicBlock = false;
EndSequence = false;
PrologueEnd = false;
EpilogueBegin = false;
}
void DWARFDebugLine::Row::dumpTableHeader(raw_ostream &OS) {
OS << "Address Line Column File ISA Discriminator Flags\n"
<< "------------------ ------ ------ ------ --- ------------- "
"-------------\n";
}
void DWARFDebugLine::Row::dump(raw_ostream &OS) const {
OS << format("0x%16.16" PRIx64 " %6u %6u", Address.Address, Line, Column)
<< format(" %6u %3u %13u ", File, Isa, Discriminator)
<< (IsStmt ? " is_stmt" : "") << (BasicBlock ? " basic_block" : "")
<< (PrologueEnd ? " prologue_end" : "")
<< (EpilogueBegin ? " epilogue_begin" : "")
<< (EndSequence ? " end_sequence" : "") << '\n';
}
DWARFDebugLine::Sequence::Sequence() { reset(); }
void DWARFDebugLine::Sequence::reset() {
LowPC = 0;
HighPC = 0;
SectionIndex = object::SectionedAddress::UndefSection;
FirstRowIndex = 0;
LastRowIndex = 0;
Empty = true;
}
DWARFDebugLine::LineTable::LineTable() { clear(); }
void DWARFDebugLine::LineTable::dump(raw_ostream &OS,
DIDumpOptions DumpOptions) const {
Prologue.dump(OS, DumpOptions);
OS << '\n';
if (!Rows.empty()) {
Row::dumpTableHeader(OS);
for (const Row &R : Rows) {
R.dump(OS);
}
}
}
void DWARFDebugLine::LineTable::clear() {
Prologue.clear();
Rows.clear();
Sequences.clear();
}
DWARFDebugLine::ParsingState::ParsingState(struct LineTable *LT)
: LineTable(LT) {
resetRowAndSequence();
}
void DWARFDebugLine::ParsingState::resetRowAndSequence() {
Row.reset(LineTable->Prologue.DefaultIsStmt);
Sequence.reset();
}
void DWARFDebugLine::ParsingState::appendRowToMatrix() {
unsigned RowNumber = LineTable->Rows.size();
if (Sequence.Empty) {
// Record the beginning of instruction sequence.
Sequence.Empty = false;
Sequence.LowPC = Row.Address.Address;
Sequence.FirstRowIndex = RowNumber;
}
LineTable->appendRow(Row);
if (Row.EndSequence) {
// Record the end of instruction sequence.
Sequence.HighPC = Row.Address.Address;
Sequence.LastRowIndex = RowNumber + 1;
Sequence.SectionIndex = Row.Address.SectionIndex;
if (Sequence.isValid())
LineTable->appendSequence(Sequence);
Sequence.reset();
}
Row.postAppend();
}
const DWARFDebugLine::LineTable *
DWARFDebugLine::getLineTable(uint64_t Offset) const {
LineTableConstIter Pos = LineTableMap.find(Offset);
if (Pos != LineTableMap.end())
return &Pos->second;
return nullptr;
}
Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
DWARFDataExtractor &DebugLineData, uint64_t Offset, const DWARFContext &Ctx,
const DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
if (!DebugLineData.isValidOffset(Offset))
return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx64
" is not a valid debug line section offset",
Offset);
std::pair<LineTableIter, bool> Pos =
LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
LineTable *LT = &Pos.first->second;
if (Pos.second) {
if (Error Err =
LT->parse(DebugLineData, &Offset, Ctx, U, RecoverableErrorCallback))
return std::move(Err);
return LT;
}
return LT;
}
Error DWARFDebugLine::LineTable::parse(
DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
const DWARFContext &Ctx, const DWARFUnit *U,
std::function<void(Error)> RecoverableErrorCallback, raw_ostream *OS) {
const uint64_t DebugLineOffset = *OffsetPtr;
clear();
Error PrologueErr = Prologue.parse(DebugLineData, OffsetPtr, Ctx, U);
if (OS) {
// The presence of OS signals verbose dumping.
DIDumpOptions DumpOptions;
DumpOptions.Verbose = true;
Prologue.dump(*OS, DumpOptions);
}
if (PrologueErr)
return PrologueErr;
const uint64_t EndOffset =
DebugLineOffset + Prologue.TotalLength + Prologue.sizeofTotalLength();
// See if we should tell the data extractor the address size.
if (DebugLineData.getAddressSize() == 0)
DebugLineData.setAddressSize(Prologue.getAddressSize());
else
assert(Prologue.getAddressSize() == 0 ||
Prologue.getAddressSize() == DebugLineData.getAddressSize());
ParsingState State(this);
while (*OffsetPtr < EndOffset) {
if (OS)
*OS << format("0x%08.08" PRIx64 ": ", *OffsetPtr);
uint8_t Opcode = DebugLineData.getU8(OffsetPtr);
if (OS)
*OS << format("%02.02" PRIx8 " ", Opcode);
if (Opcode == 0) {
// Extended Opcodes always start with a zero opcode followed by
// a uleb128 length so you can skip ones you don't know about
uint64_t Len = DebugLineData.getULEB128(OffsetPtr);
uint64_t ExtOffset = *OffsetPtr;
// Tolerate zero-length; assume length is correct and soldier on.
if (Len == 0) {
if (OS)
*OS << "Badly formed extended line op (length 0)\n";
continue;
}
uint8_t SubOpcode = DebugLineData.getU8(OffsetPtr);
if (OS)
*OS << LNExtendedString(SubOpcode);
switch (SubOpcode) {
case DW_LNE_end_sequence:
// Set the end_sequence register of the state machine to true and
// append a row to the matrix using the current values of the
// state-machine registers. Then reset the registers to the initial
// values specified above. Every statement program sequence must end
// with a DW_LNE_end_sequence instruction which creates a row whose
// address is that of the byte after the last target machine instruction
// of the sequence.
State.Row.EndSequence = true;
State.appendRowToMatrix();
if (OS) {
*OS << "\n";
OS->indent(12);
State.Row.dump(*OS);
}
State.resetRowAndSequence();
break;
case DW_LNE_set_address:
// Takes a single relocatable address as an operand. The size of the
// operand is the size appropriate to hold an address on the target
// machine. Set the address register to the value given by the
// relocatable address. All of the other statement program opcodes
// that affect the address register add a delta to it. This instruction
// stores a relocatable value into it instead.
//
// Make sure the extractor knows the address size. If not, infer it
// from the size of the operand.
if (DebugLineData.getAddressSize() == 0)
DebugLineData.setAddressSize(Len - 1);
else if (DebugLineData.getAddressSize() != Len - 1) {
return createStringError(errc::invalid_argument,
"mismatching address size at offset 0x%8.8" PRIx64
" expected 0x%2.2" PRIx8 " found 0x%2.2" PRIx64,
ExtOffset, DebugLineData.getAddressSize(),
Len - 1);
}
State.Row.Address.Address = DebugLineData.getRelocatedAddress(
OffsetPtr, &State.Row.Address.SectionIndex);
if (OS)
*OS << format(" (0x%16.16" PRIx64 ")", State.Row.Address.Address);
break;
case DW_LNE_define_file:
// Takes 4 arguments. The first is a null terminated string containing
// a source file name. The second is an unsigned LEB128 number
// representing the directory index of the directory in which the file
// was found. The third is an unsigned LEB128 number representing the
// time of last modification of the file. The fourth is an unsigned
// LEB128 number representing the length in bytes of the file. The time
// and length fields may contain LEB128(0) if the information is not
// available.
//
// The directory index represents an entry in the include_directories
// section of the statement program prologue. The index is LEB128(0)
// if the file was found in the current directory of the compilation,
// LEB128(1) if it was found in the first directory in the
// include_directories section, and so on. The directory index is
// ignored for file names that represent full path names.
//
// The files are numbered, starting at 1, in the order in which they
// appear; the names in the prologue come before names defined by
// the DW_LNE_define_file instruction. These numbers are used in the
// the file register of the state machine.
{
FileNameEntry FileEntry;
const char *Name = DebugLineData.getCStr(OffsetPtr);
FileEntry.Name =
DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name);
FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
Prologue.FileNames.push_back(FileEntry);
if (OS)
*OS << " (" << Name << ", dir=" << FileEntry.DirIdx << ", mod_time="
<< format("(0x%16.16" PRIx64 ")", FileEntry.ModTime)
<< ", length=" << FileEntry.Length << ")";
}
break;
case DW_LNE_set_discriminator:
State.Row.Discriminator = DebugLineData.getULEB128(OffsetPtr);
if (OS)
*OS << " (" << State.Row.Discriminator << ")";
break;
default:
if (OS)
*OS << format("Unrecognized extended op 0x%02.02" PRIx8, SubOpcode)
<< format(" length %" PRIx64, Len);
// Len doesn't include the zero opcode byte or the length itself, but
// it does include the sub_opcode, so we have to adjust for that.
(*OffsetPtr) += Len - 1;
break;
}
// Make sure the stated and parsed lengths are the same.
// Otherwise we have an unparseable line-number program.
if (*OffsetPtr - ExtOffset != Len)
return createStringError(errc::illegal_byte_sequence,
"unexpected line op length at offset 0x%8.8" PRIx64
" expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx64,
ExtOffset, Len, *OffsetPtr - ExtOffset);
} else if (Opcode < Prologue.OpcodeBase) {
if (OS)
*OS << LNStandardString(Opcode);
switch (Opcode) {
// Standard Opcodes
case DW_LNS_copy:
// Takes no arguments. Append a row to the matrix using the
// current values of the state-machine registers.
if (OS) {
*OS << "\n";
OS->indent(12);
State.Row.dump(*OS);
*OS << "\n";
}
State.appendRowToMatrix();
break;
case DW_LNS_advance_pc:
// Takes a single unsigned LEB128 operand, multiplies it by the
// min_inst_length field of the prologue, and adds the
// result to the address register of the state machine.
{
uint64_t AddrOffset =
DebugLineData.getULEB128(OffsetPtr) * Prologue.MinInstLength;
State.Row.Address.Address += AddrOffset;
if (OS)
*OS << " (" << AddrOffset << ")";
}
break;
case DW_LNS_advance_line:
// Takes a single signed LEB128 operand and adds that value to
// the line register of the state machine.
State.Row.Line += DebugLineData.getSLEB128(OffsetPtr);
if (OS)
*OS << " (" << State.Row.Line << ")";
break;
case DW_LNS_set_file:
// Takes a single unsigned LEB128 operand and stores it in the file
// register of the state machine.
State.Row.File = DebugLineData.getULEB128(OffsetPtr);
if (OS)
*OS << " (" << State.Row.File << ")";
break;
case DW_LNS_set_column:
// Takes a single unsigned LEB128 operand and stores it in the
// column register of the state machine.
State.Row.Column = DebugLineData.getULEB128(OffsetPtr);
if (OS)
*OS << " (" << State.Row.Column << ")";
break;
case DW_LNS_negate_stmt:
// Takes no arguments. Set the is_stmt register of the state
// machine to the logical negation of its current value.
State.Row.IsStmt = !State.Row.IsStmt;
break;
case DW_LNS_set_basic_block:
// Takes no arguments. Set the basic_block register of the
// state machine to true
State.Row.BasicBlock = true;
break;
case DW_LNS_const_add_pc:
// Takes no arguments. Add to the address register of the state
// machine the address increment value corresponding to special
// opcode 255. The motivation for DW_LNS_const_add_pc is this:
// when the statement program needs to advance the address by a
// small amount, it can use a single special opcode, which occupies
// a single byte. When it needs to advance the address by up to
// twice the range of the last special opcode, it can use
// DW_LNS_const_add_pc followed by a special opcode, for a total
// of two bytes. Only if it needs to advance the address by more
// than twice that range will it need to use both DW_LNS_advance_pc
// and a special opcode, requiring three or more bytes.
{
uint8_t AdjustOpcode = 255 - Prologue.OpcodeBase;
uint64_t AddrOffset =
(AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
State.Row.Address.Address += AddrOffset;
if (OS)
*OS
<< format(" (0x%16.16" PRIx64 ")", AddrOffset);
}
break;
case DW_LNS_fixed_advance_pc:
// Takes a single uhalf operand. Add to the address register of
// the state machine the value of the (unencoded) operand. This
// is the only extended opcode that takes an argument that is not
// a variable length number. The motivation for DW_LNS_fixed_advance_pc
// is this: existing assemblers cannot emit DW_LNS_advance_pc or
// special opcodes because they cannot encode LEB128 numbers or
// judge when the computation of a special opcode overflows and
// requires the use of DW_LNS_advance_pc. Such assemblers, however,
// can use DW_LNS_fixed_advance_pc instead, sacrificing compression.
{
uint16_t PCOffset = DebugLineData.getRelocatedValue(2, OffsetPtr);
State.Row.Address.Address += PCOffset;
if (OS)
*OS
<< format(" (0x%4.4" PRIx16 ")", PCOffset);
}
break;
case DW_LNS_set_prologue_end:
// Takes no arguments. Set the prologue_end register of the
// state machine to true
State.Row.PrologueEnd = true;
break;
case DW_LNS_set_epilogue_begin:
// Takes no arguments. Set the basic_block register of the
// state machine to true
State.Row.EpilogueBegin = true;
break;
case DW_LNS_set_isa:
// Takes a single unsigned LEB128 operand and stores it in the
// column register of the state machine.
State.Row.Isa = DebugLineData.getULEB128(OffsetPtr);
if (OS)
*OS << " (" << State.Row.Isa << ")";
break;
default:
// Handle any unknown standard opcodes here. We know the lengths
// of such opcodes because they are specified in the prologue
// as a multiple of LEB128 operands for each opcode.
{
assert(Opcode - 1U < Prologue.StandardOpcodeLengths.size());
uint8_t OpcodeLength = Prologue.StandardOpcodeLengths[Opcode - 1];
for (uint8_t I = 0; I < OpcodeLength; ++I) {
uint64_t Value = DebugLineData.getULEB128(OffsetPtr);
if (OS)
*OS << format("Skipping ULEB128 value: 0x%16.16" PRIx64 ")\n",
Value);
}
}
break;
}
} else {
// Special Opcodes
// A special opcode value is chosen based on the amount that needs
// to be added to the line and address registers. The maximum line
// increment for a special opcode is the value of the line_base
// field in the header, plus the value of the line_range field,
// minus 1 (line base + line range - 1). If the desired line
// increment is greater than the maximum line increment, a standard
// opcode must be used instead of a special opcode. The "address
// advance" is calculated by dividing the desired address increment
// by the minimum_instruction_length field from the header. The
// special opcode is then calculated using the following formula:
//
// opcode = (desired line increment - line_base) +
// (line_range * address advance) + opcode_base
//
// If the resulting opcode is greater than 255, a standard opcode
// must be used instead.
//
// To decode a special opcode, subtract the opcode_base from the
// opcode itself to give the adjusted opcode. The amount to
// increment the address register is the result of the adjusted
// opcode divided by the line_range multiplied by the
// minimum_instruction_length field from the header. That is:
//
// address increment = (adjusted opcode / line_range) *
// minimum_instruction_length
//
// The amount to increment the line register is the line_base plus
// the result of the adjusted opcode modulo the line_range. That is:
//
// line increment = line_base + (adjusted opcode % line_range)
uint8_t AdjustOpcode = Opcode - Prologue.OpcodeBase;
uint64_t AddrOffset =
(AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
int32_t LineOffset =
Prologue.LineBase + (AdjustOpcode % Prologue.LineRange);
State.Row.Line += LineOffset;
State.Row.Address.Address += AddrOffset;
if (OS) {
*OS << "address += " << AddrOffset << ", line += " << LineOffset
<< "\n";
OS->indent(12);
State.Row.dump(*OS);
}
State.appendRowToMatrix();
}
if(OS)
*OS << "\n";
}
if (!State.Sequence.Empty)
RecoverableErrorCallback(
createStringError(errc::illegal_byte_sequence,
"last sequence in debug line table is not terminated!"));
// Sort all sequences so that address lookup will work faster.
if (!Sequences.empty()) {
llvm::sort(Sequences, Sequence::orderByHighPC);
// Note: actually, instruction address ranges of sequences should not
// overlap (in shared objects and executables). If they do, the address
// lookup would still work, though, but result would be ambiguous.
// We don't report warning in this case. For example,
// sometimes .so compiled from multiple object files contains a few
// rudimentary sequences for address ranges [0x0, 0xsomething).
}
return Error::success();
}
uint32_t DWARFDebugLine::LineTable::findRowInSeq(
const DWARFDebugLine::Sequence &Seq,
object::SectionedAddress Address) const {
if (!Seq.containsPC(Address))
return UnknownRowIndex;
assert(Seq.SectionIndex == Address.SectionIndex);
// In some cases, e.g. first instruction in a function, the compiler generates
// two entries, both with the same address. We want the last one.
//
// In general we want a non-empty range: the last row whose address is less
// than or equal to Address. This can be computed as upper_bound - 1.
DWARFDebugLine::Row Row;
Row.Address = Address;
RowIter FirstRow = Rows.begin() + Seq.FirstRowIndex;
RowIter LastRow = Rows.begin() + Seq.LastRowIndex;
assert(FirstRow->Address.Address <= Row.Address.Address &&
Row.Address.Address < LastRow[-1].Address.Address);
RowIter RowPos = std::upper_bound(FirstRow + 1, LastRow - 1, Row,
DWARFDebugLine::Row::orderByAddress) -
1;
assert(Seq.SectionIndex == RowPos->Address.SectionIndex);
return RowPos - Rows.begin();
}
uint32_t DWARFDebugLine::LineTable::lookupAddress(
object::SectionedAddress Address) const {
// Search for relocatable addresses
uint32_t Result = lookupAddressImpl(Address);
if (Result != UnknownRowIndex ||
Address.SectionIndex == object::SectionedAddress::UndefSection)
return Result;
// Search for absolute addresses
Address.SectionIndex = object::SectionedAddress::UndefSection;
return lookupAddressImpl(Address);
}
uint32_t DWARFDebugLine::LineTable::lookupAddressImpl(
object::SectionedAddress Address) const {
// First, find an instruction sequence containing the given address.
DWARFDebugLine::Sequence Sequence;
Sequence.SectionIndex = Address.SectionIndex;
Sequence.HighPC = Address.Address;
SequenceIter It = llvm::upper_bound(Sequences, Sequence,
DWARFDebugLine::Sequence::orderByHighPC);
if (It == Sequences.end() || It->SectionIndex != Address.SectionIndex)
return UnknownRowIndex;
return findRowInSeq(*It, Address);
}
bool DWARFDebugLine::LineTable::lookupAddressRange(
object::SectionedAddress Address, uint64_t Size,
std::vector<uint32_t> &Result) const {
// Search for relocatable addresses
if (lookupAddressRangeImpl(Address, Size, Result))
return true;
if (Address.SectionIndex == object::SectionedAddress::UndefSection)
return false;
// Search for absolute addresses
Address.SectionIndex = object::SectionedAddress::UndefSection;
return lookupAddressRangeImpl(Address, Size, Result);
}
bool DWARFDebugLine::LineTable::lookupAddressRangeImpl(
object::SectionedAddress Address, uint64_t Size,
std::vector<uint32_t> &Result) const {
if (Sequences.empty())
return false;
uint64_t EndAddr = Address.Address + Size;
// First, find an instruction sequence containing the given address.
DWARFDebugLine::Sequence Sequence;
Sequence.SectionIndex = Address.SectionIndex;
Sequence.HighPC = Address.Address;
SequenceIter LastSeq = Sequences.end();
SequenceIter SeqPos = llvm::upper_bound(
Sequences, Sequence, DWARFDebugLine::Sequence::orderByHighPC);
if (SeqPos == LastSeq || !SeqPos->containsPC(Address))
return false;
SequenceIter StartPos = SeqPos;
// Add the rows from the first sequence to the vector, starting with the
// index we just calculated
while (SeqPos != LastSeq && SeqPos->LowPC < EndAddr) {
const DWARFDebugLine::Sequence &CurSeq = *SeqPos;
// For the first sequence, we need to find which row in the sequence is the