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llvm-mirror/lib/ObjectYAML/DWARFEmitter.cpp
Pavel Labath e992eb498a Recommit "[DWARF] Add an api to get "interpreted" location lists"
This recommits 089c0f581492cd6e2a3d2927be3fbf60ea2d7e62, which was
reverted due to failing tests on big endian machines. It includes a fix
which I believe (I don't have BE machine) should fix this issue. The fix
consists of correcting the invocation DWARFYAML::EmitDebugSections,
which was missing one (default) function arguments, and so didn't
actually force the little-endian mode.

The original commit message follows.

Summary:
This patch adds DWARFDie::getLocations, which returns the location
expressions for a given attribute (typically DW_AT_location). It handles
both "inline" locations and references to the external location list
sections (currently only of the DW_FORM_sec_offset type). It is
implemented on top of DWARFUnit::findLoclistFromOffset, which is also
added in this patch. I tried to make their signatures similar to the
equivalent range list functionality.

The actual location list interpretation logic is in
DWARFLocationTable::visitAbsoluteLocationList. This part is not
equivalent to the range list code, but this deviation is motivated by a
desire to reuse the same location list parsing code within lldb.

The functionality is tested via a c++ unit test of the DWARFDie API.

Reviewers: dblaikie, JDevlieghere, SouraVX

Subscribers: mgorny, hiraditya, cmtice, probinson, llvm-commits, aprantl

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70394
2019-11-20 16:24:11 +01:00

382 lines
13 KiB
C++

//===- DWARFEmitter - Convert YAML to DWARF binary data -------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// The DWARF component of yaml2obj. Provided as library code for tests.
///
//===----------------------------------------------------------------------===//
#include "llvm/ObjectYAML/DWARFEmitter.h"
#include "DWARFVisitor.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ObjectYAML/DWARFYAML.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SwapByteOrder.h"
#include "llvm/Support/YAMLTraits.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
#include <vector>
using namespace llvm;
template <typename T>
static void writeInteger(T Integer, raw_ostream &OS, bool IsLittleEndian) {
if (IsLittleEndian != sys::IsLittleEndianHost)
sys::swapByteOrder(Integer);
OS.write(reinterpret_cast<char *>(&Integer), sizeof(T));
}
static void writeVariableSizedInteger(uint64_t Integer, size_t Size,
raw_ostream &OS, bool IsLittleEndian) {
if (8 == Size)
writeInteger((uint64_t)Integer, OS, IsLittleEndian);
else if (4 == Size)
writeInteger((uint32_t)Integer, OS, IsLittleEndian);
else if (2 == Size)
writeInteger((uint16_t)Integer, OS, IsLittleEndian);
else if (1 == Size)
writeInteger((uint8_t)Integer, OS, IsLittleEndian);
else
assert(false && "Invalid integer write size.");
}
static void ZeroFillBytes(raw_ostream &OS, size_t Size) {
std::vector<uint8_t> FillData;
FillData.insert(FillData.begin(), Size, 0);
OS.write(reinterpret_cast<char *>(FillData.data()), Size);
}
static void writeInitialLength(const DWARFYAML::InitialLength &Length,
raw_ostream &OS, bool IsLittleEndian) {
writeInteger((uint32_t)Length.TotalLength, OS, IsLittleEndian);
if (Length.isDWARF64())
writeInteger((uint64_t)Length.TotalLength64, OS, IsLittleEndian);
}
void DWARFYAML::EmitDebugStr(raw_ostream &OS, const DWARFYAML::Data &DI) {
for (auto Str : DI.DebugStrings) {
OS.write(Str.data(), Str.size());
OS.write('\0');
}
}
void DWARFYAML::EmitDebugAbbrev(raw_ostream &OS, const DWARFYAML::Data &DI) {
for (auto AbbrevDecl : DI.AbbrevDecls) {
encodeULEB128(AbbrevDecl.Code, OS);
encodeULEB128(AbbrevDecl.Tag, OS);
OS.write(AbbrevDecl.Children);
for (auto Attr : AbbrevDecl.Attributes) {
encodeULEB128(Attr.Attribute, OS);
encodeULEB128(Attr.Form, OS);
if (Attr.Form == dwarf::DW_FORM_implicit_const)
encodeSLEB128(Attr.Value, OS);
}
encodeULEB128(0, OS);
encodeULEB128(0, OS);
}
}
void DWARFYAML::EmitDebugAranges(raw_ostream &OS, const DWARFYAML::Data &DI) {
for (auto Range : DI.ARanges) {
auto HeaderStart = OS.tell();
writeInitialLength(Range.Length, OS, DI.IsLittleEndian);
writeInteger((uint16_t)Range.Version, OS, DI.IsLittleEndian);
writeInteger((uint32_t)Range.CuOffset, OS, DI.IsLittleEndian);
writeInteger((uint8_t)Range.AddrSize, OS, DI.IsLittleEndian);
writeInteger((uint8_t)Range.SegSize, OS, DI.IsLittleEndian);
auto HeaderSize = OS.tell() - HeaderStart;
auto FirstDescriptor = alignTo(HeaderSize, Range.AddrSize * 2);
ZeroFillBytes(OS, FirstDescriptor - HeaderSize);
for (auto Descriptor : Range.Descriptors) {
writeVariableSizedInteger(Descriptor.Address, Range.AddrSize, OS,
DI.IsLittleEndian);
writeVariableSizedInteger(Descriptor.Length, Range.AddrSize, OS,
DI.IsLittleEndian);
}
ZeroFillBytes(OS, Range.AddrSize * 2);
}
}
void DWARFYAML::EmitPubSection(raw_ostream &OS,
const DWARFYAML::PubSection &Sect,
bool IsLittleEndian) {
writeInitialLength(Sect.Length, OS, IsLittleEndian);
writeInteger((uint16_t)Sect.Version, OS, IsLittleEndian);
writeInteger((uint32_t)Sect.UnitOffset, OS, IsLittleEndian);
writeInteger((uint32_t)Sect.UnitSize, OS, IsLittleEndian);
for (auto Entry : Sect.Entries) {
writeInteger((uint32_t)Entry.DieOffset, OS, IsLittleEndian);
if (Sect.IsGNUStyle)
writeInteger((uint32_t)Entry.Descriptor, OS, IsLittleEndian);
OS.write(Entry.Name.data(), Entry.Name.size());
OS.write('\0');
}
}
namespace {
/// An extension of the DWARFYAML::ConstVisitor which writes compile
/// units and DIEs to a stream.
class DumpVisitor : public DWARFYAML::ConstVisitor {
raw_ostream &OS;
protected:
void onStartCompileUnit(const DWARFYAML::Unit &CU) override {
writeInitialLength(CU.Length, OS, DebugInfo.IsLittleEndian);
writeInteger((uint16_t)CU.Version, OS, DebugInfo.IsLittleEndian);
if(CU.Version >= 5) {
writeInteger((uint8_t)CU.Type, OS, DebugInfo.IsLittleEndian);
writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian);
writeInteger((uint32_t)CU.AbbrOffset, OS, DebugInfo.IsLittleEndian);
}else {
writeInteger((uint32_t)CU.AbbrOffset, OS, DebugInfo.IsLittleEndian);
writeInteger((uint8_t)CU.AddrSize, OS, DebugInfo.IsLittleEndian);
}
}
void onStartDIE(const DWARFYAML::Unit &CU,
const DWARFYAML::Entry &DIE) override {
encodeULEB128(DIE.AbbrCode, OS);
}
void onValue(const uint8_t U) override {
writeInteger(U, OS, DebugInfo.IsLittleEndian);
}
void onValue(const uint16_t U) override {
writeInteger(U, OS, DebugInfo.IsLittleEndian);
}
void onValue(const uint32_t U) override {
writeInteger(U, OS, DebugInfo.IsLittleEndian);
}
void onValue(const uint64_t U, const bool LEB = false) override {
if (LEB)
encodeULEB128(U, OS);
else
writeInteger(U, OS, DebugInfo.IsLittleEndian);
}
void onValue(const int64_t S, const bool LEB = false) override {
if (LEB)
encodeSLEB128(S, OS);
else
writeInteger(S, OS, DebugInfo.IsLittleEndian);
}
void onValue(const StringRef String) override {
OS.write(String.data(), String.size());
OS.write('\0');
}
void onValue(const MemoryBufferRef MBR) override {
OS.write(MBR.getBufferStart(), MBR.getBufferSize());
}
public:
DumpVisitor(const DWARFYAML::Data &DI, raw_ostream &Out)
: DWARFYAML::ConstVisitor(DI), OS(Out) {}
};
} // namespace
void DWARFYAML::EmitDebugInfo(raw_ostream &OS, const DWARFYAML::Data &DI) {
DumpVisitor Visitor(DI, OS);
Visitor.traverseDebugInfo();
}
static void EmitFileEntry(raw_ostream &OS, const DWARFYAML::File &File) {
OS.write(File.Name.data(), File.Name.size());
OS.write('\0');
encodeULEB128(File.DirIdx, OS);
encodeULEB128(File.ModTime, OS);
encodeULEB128(File.Length, OS);
}
void DWARFYAML::EmitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) {
for (const auto &LineTable : DI.DebugLines) {
writeInitialLength(LineTable.Length, OS, DI.IsLittleEndian);
uint64_t SizeOfPrologueLength = LineTable.Length.isDWARF64() ? 8 : 4;
writeInteger((uint16_t)LineTable.Version, OS, DI.IsLittleEndian);
writeVariableSizedInteger(LineTable.PrologueLength, SizeOfPrologueLength,
OS, DI.IsLittleEndian);
writeInteger((uint8_t)LineTable.MinInstLength, OS, DI.IsLittleEndian);
if (LineTable.Version >= 4)
writeInteger((uint8_t)LineTable.MaxOpsPerInst, OS, DI.IsLittleEndian);
writeInteger((uint8_t)LineTable.DefaultIsStmt, OS, DI.IsLittleEndian);
writeInteger((uint8_t)LineTable.LineBase, OS, DI.IsLittleEndian);
writeInteger((uint8_t)LineTable.LineRange, OS, DI.IsLittleEndian);
writeInteger((uint8_t)LineTable.OpcodeBase, OS, DI.IsLittleEndian);
for (auto OpcodeLength : LineTable.StandardOpcodeLengths)
writeInteger((uint8_t)OpcodeLength, OS, DI.IsLittleEndian);
for (auto IncludeDir : LineTable.IncludeDirs) {
OS.write(IncludeDir.data(), IncludeDir.size());
OS.write('\0');
}
OS.write('\0');
for (auto File : LineTable.Files)
EmitFileEntry(OS, File);
OS.write('\0');
for (auto Op : LineTable.Opcodes) {
writeInteger((uint8_t)Op.Opcode, OS, DI.IsLittleEndian);
if (Op.Opcode == 0) {
encodeULEB128(Op.ExtLen, OS);
writeInteger((uint8_t)Op.SubOpcode, OS, DI.IsLittleEndian);
switch (Op.SubOpcode) {
case dwarf::DW_LNE_set_address:
case dwarf::DW_LNE_set_discriminator:
writeVariableSizedInteger(Op.Data, DI.CompileUnits[0].AddrSize, OS,
DI.IsLittleEndian);
break;
case dwarf::DW_LNE_define_file:
EmitFileEntry(OS, Op.FileEntry);
break;
case dwarf::DW_LNE_end_sequence:
break;
default:
for (auto OpByte : Op.UnknownOpcodeData)
writeInteger((uint8_t)OpByte, OS, DI.IsLittleEndian);
}
} else if (Op.Opcode < LineTable.OpcodeBase) {
switch (Op.Opcode) {
case dwarf::DW_LNS_copy:
case dwarf::DW_LNS_negate_stmt:
case dwarf::DW_LNS_set_basic_block:
case dwarf::DW_LNS_const_add_pc:
case dwarf::DW_LNS_set_prologue_end:
case dwarf::DW_LNS_set_epilogue_begin:
break;
case dwarf::DW_LNS_advance_pc:
case dwarf::DW_LNS_set_file:
case dwarf::DW_LNS_set_column:
case dwarf::DW_LNS_set_isa:
encodeULEB128(Op.Data, OS);
break;
case dwarf::DW_LNS_advance_line:
encodeSLEB128(Op.SData, OS);
break;
case dwarf::DW_LNS_fixed_advance_pc:
writeInteger((uint16_t)Op.Data, OS, DI.IsLittleEndian);
break;
default:
for (auto OpData : Op.StandardOpcodeData) {
encodeULEB128(OpData, OS);
}
}
}
}
}
}
using EmitFuncType = void (*)(raw_ostream &, const DWARFYAML::Data &);
static void
EmitDebugSectionImpl(const DWARFYAML::Data &DI, EmitFuncType EmitFunc,
StringRef Sec,
StringMap<std::unique_ptr<MemoryBuffer>> &OutputBuffers) {
std::string Data;
raw_string_ostream DebugInfoStream(Data);
EmitFunc(DebugInfoStream, DI);
DebugInfoStream.flush();
if (!Data.empty())
OutputBuffers[Sec] = MemoryBuffer::getMemBufferCopy(Data);
}
namespace {
class DIEFixupVisitor : public DWARFYAML::Visitor {
uint64_t Length;
public:
DIEFixupVisitor(DWARFYAML::Data &DI) : DWARFYAML::Visitor(DI){};
private:
virtual void onStartCompileUnit(DWARFYAML::Unit &CU) {
// Size of the unit header, excluding the length field itself.
Length = CU.Version >= 5 ? 8 : 7;
}
virtual void onEndCompileUnit(DWARFYAML::Unit &CU) {
CU.Length.setLength(Length);
}
virtual void onStartDIE(DWARFYAML::Unit &CU, DWARFYAML::Entry &DIE) {
Length += getULEB128Size(DIE.AbbrCode);
}
virtual void onValue(const uint8_t U) { Length += 1; }
virtual void onValue(const uint16_t U) { Length += 2; }
virtual void onValue(const uint32_t U) { Length += 4; }
virtual void onValue(const uint64_t U, const bool LEB = false) {
if (LEB)
Length += getULEB128Size(U);
else
Length += 8;
}
virtual void onValue(const int64_t S, const bool LEB = false) {
if (LEB)
Length += getSLEB128Size(S);
else
Length += 8;
}
virtual void onValue(const StringRef String) { Length += String.size() + 1; }
virtual void onValue(const MemoryBufferRef MBR) {
Length += MBR.getBufferSize();
}
};
} // namespace
Expected<StringMap<std::unique_ptr<MemoryBuffer>>>
DWARFYAML::EmitDebugSections(StringRef YAMLString, bool ApplyFixups,
bool IsLittleEndian) {
yaml::Input YIn(YAMLString);
DWARFYAML::Data DI;
DI.IsLittleEndian = IsLittleEndian;
YIn >> DI;
if (YIn.error())
return errorCodeToError(YIn.error());
if (ApplyFixups) {
DIEFixupVisitor DIFixer(DI);
DIFixer.traverseDebugInfo();
}
StringMap<std::unique_ptr<MemoryBuffer>> DebugSections;
EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugInfo, "debug_info",
DebugSections);
EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugLine, "debug_line",
DebugSections);
EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugStr, "debug_str",
DebugSections);
EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAbbrev, "debug_abbrev",
DebugSections);
EmitDebugSectionImpl(DI, &DWARFYAML::EmitDebugAranges, "debug_aranges",
DebugSections);
return std::move(DebugSections);
}