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bd2df13ee0f972ac386fd2d8edf5a9205ace04bb
clang-p2996/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
Igor Kudrin bd2df13ee0 [DebugInfo] Fix printing CIE offsets in EH FDEs. 
While the value of the CIE pointer field in a DWARF FDE record is
an offset to the corresponding CIE record from the beginning of
the section, for EH FDE records it is relative to the current offset.
Previously, we did not make that distinction when dumped both kinds
of FDE records and just printed the same value for the CIE pointer
field and the CIE offset; that was acceptable for DWARF FDEs but was
wrong for EH FDEs.

This patch fixes the issue by explicitly printing the offset of the
linked CIE object.

Differential Revision: https://reviews.llvm.org/D74613
2020-02-25 17:10:29 +07:00

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//===- DWARFDebugFrame.h - Parsing of .debug_frame ------------------------===//
//
// 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/DWARFDebugFrame.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <cstdint>
#include <string>
#include <vector>
using namespace llvm;
using namespace dwarf;
// See DWARF standard v3, section 7.23
const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0;
const uint8_t DWARF_CFI_PRIMARY_OPERAND_MASK = 0x3f;
Error CFIProgram::parse(DWARFDataExtractor Data, uint64_t *Offset,
uint64_t EndOffset) {
while (*Offset < EndOffset) {
uint8_t Opcode = Data.getRelocatedValue(1, Offset);
// Some instructions have a primary opcode encoded in the top bits.
uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK;
if (Primary) {
// If it's a primary opcode, the first operand is encoded in the bottom
// bits of the opcode itself.
uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK;
switch (Primary) {
default:
return createStringError(errc::illegal_byte_sequence,
"Invalid primary CFI opcode 0x%" PRIx8,
Primary);
case DW_CFA_advance_loc:
case DW_CFA_restore:
addInstruction(Primary, Op1);
break;
case DW_CFA_offset:
addInstruction(Primary, Op1, Data.getULEB128(Offset));
break;
}
} else {
// Extended opcode - its value is Opcode itself.
switch (Opcode) {
default:
return createStringError(errc::illegal_byte_sequence,
"Invalid extended CFI opcode 0x%" PRIx8,
Opcode);
case DW_CFA_nop:
case DW_CFA_remember_state:
case DW_CFA_restore_state:
case DW_CFA_GNU_window_save:
// No operands
addInstruction(Opcode);
break;
case DW_CFA_set_loc:
// Operands: Address
addInstruction(Opcode, Data.getRelocatedAddress(Offset));
break;
case DW_CFA_advance_loc1:
// Operands: 1-byte delta
addInstruction(Opcode, Data.getRelocatedValue(1, Offset));
break;
case DW_CFA_advance_loc2:
// Operands: 2-byte delta
addInstruction(Opcode, Data.getRelocatedValue(2, Offset));
break;
case DW_CFA_advance_loc4:
// Operands: 4-byte delta
addInstruction(Opcode, Data.getRelocatedValue(4, Offset));
break;
case DW_CFA_restore_extended:
case DW_CFA_undefined:
case DW_CFA_same_value:
case DW_CFA_def_cfa_register:
case DW_CFA_def_cfa_offset:
case DW_CFA_GNU_args_size:
// Operands: ULEB128
addInstruction(Opcode, Data.getULEB128(Offset));
break;
case DW_CFA_def_cfa_offset_sf:
// Operands: SLEB128
addInstruction(Opcode, Data.getSLEB128(Offset));
break;
case DW_CFA_offset_extended:
case DW_CFA_register:
case DW_CFA_def_cfa:
case DW_CFA_val_offset: {
// Operands: ULEB128, ULEB128
// Note: We can not embed getULEB128 directly into function
// argument list. getULEB128 changes Offset and order of evaluation
// for arguments is unspecified.
auto op1 = Data.getULEB128(Offset);
auto op2 = Data.getULEB128(Offset);
addInstruction(Opcode, op1, op2);
break;
}
case DW_CFA_offset_extended_sf:
case DW_CFA_def_cfa_sf:
case DW_CFA_val_offset_sf: {
// Operands: ULEB128, SLEB128
// Note: see comment for the previous case
auto op1 = Data.getULEB128(Offset);
auto op2 = (uint64_t)Data.getSLEB128(Offset);
addInstruction(Opcode, op1, op2);
break;
}
case DW_CFA_def_cfa_expression: {
uint32_t ExprLength = Data.getULEB128(Offset);
addInstruction(Opcode, 0);
DataExtractor Extractor(
Data.getData().slice(*Offset, *Offset + ExprLength),
Data.isLittleEndian(), Data.getAddressSize());
Instructions.back().Expression =
DWARFExpression(Extractor, Data.getAddressSize());
*Offset += ExprLength;
break;
}
case DW_CFA_expression:
case DW_CFA_val_expression: {
auto RegNum = Data.getULEB128(Offset);
auto BlockLength = Data.getULEB128(Offset);
addInstruction(Opcode, RegNum, 0);
DataExtractor Extractor(
Data.getData().slice(*Offset, *Offset + BlockLength),
Data.isLittleEndian(), Data.getAddressSize());
Instructions.back().Expression =
DWARFExpression(Extractor, Data.getAddressSize());
*Offset += BlockLength;
break;
}
}
}
}
return Error::success();
}
namespace {
} // end anonymous namespace
ArrayRef<CFIProgram::OperandType[2]> CFIProgram::getOperandTypes() {
static OperandType OpTypes[DW_CFA_restore+1][2];
static bool Initialized = false;
if (Initialized) {
return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1);
}
Initialized = true;
#define DECLARE_OP2(OP, OPTYPE0, OPTYPE1) \
do { \
OpTypes[OP][0] = OPTYPE0; \
OpTypes[OP][1] = OPTYPE1; \
} while (false)
#define DECLARE_OP1(OP, OPTYPE0) DECLARE_OP2(OP, OPTYPE0, OT_None)
#define DECLARE_OP0(OP) DECLARE_OP1(OP, OT_None)
DECLARE_OP1(DW_CFA_set_loc, OT_Address);
DECLARE_OP1(DW_CFA_advance_loc, OT_FactoredCodeOffset);
DECLARE_OP1(DW_CFA_advance_loc1, OT_FactoredCodeOffset);
DECLARE_OP1(DW_CFA_advance_loc2, OT_FactoredCodeOffset);
DECLARE_OP1(DW_CFA_advance_loc4, OT_FactoredCodeOffset);
DECLARE_OP1(DW_CFA_MIPS_advance_loc8, OT_FactoredCodeOffset);
DECLARE_OP2(DW_CFA_def_cfa, OT_Register, OT_Offset);
DECLARE_OP2(DW_CFA_def_cfa_sf, OT_Register, OT_SignedFactDataOffset);
DECLARE_OP1(DW_CFA_def_cfa_register, OT_Register);
DECLARE_OP1(DW_CFA_def_cfa_offset, OT_Offset);
DECLARE_OP1(DW_CFA_def_cfa_offset_sf, OT_SignedFactDataOffset);
DECLARE_OP1(DW_CFA_def_cfa_expression, OT_Expression);
DECLARE_OP1(DW_CFA_undefined, OT_Register);
DECLARE_OP1(DW_CFA_same_value, OT_Register);
DECLARE_OP2(DW_CFA_offset, OT_Register, OT_UnsignedFactDataOffset);
DECLARE_OP2(DW_CFA_offset_extended, OT_Register, OT_UnsignedFactDataOffset);
DECLARE_OP2(DW_CFA_offset_extended_sf, OT_Register, OT_SignedFactDataOffset);
DECLARE_OP2(DW_CFA_val_offset, OT_Register, OT_UnsignedFactDataOffset);
DECLARE_OP2(DW_CFA_val_offset_sf, OT_Register, OT_SignedFactDataOffset);
DECLARE_OP2(DW_CFA_register, OT_Register, OT_Register);
DECLARE_OP2(DW_CFA_expression, OT_Register, OT_Expression);
DECLARE_OP2(DW_CFA_val_expression, OT_Register, OT_Expression);
DECLARE_OP1(DW_CFA_restore, OT_Register);
DECLARE_OP1(DW_CFA_restore_extended, OT_Register);
DECLARE_OP0(DW_CFA_remember_state);
DECLARE_OP0(DW_CFA_restore_state);
DECLARE_OP0(DW_CFA_GNU_window_save);
DECLARE_OP1(DW_CFA_GNU_args_size, OT_Offset);
DECLARE_OP0(DW_CFA_nop);
#undef DECLARE_OP0
#undef DECLARE_OP1
#undef DECLARE_OP2
return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1);
}
/// Print \p Opcode's operand number \p OperandIdx which has value \p Operand.
void CFIProgram::printOperand(raw_ostream &OS, const MCRegisterInfo *MRI,
bool IsEH, const Instruction &Instr,
unsigned OperandIdx, uint64_t Operand) const {
assert(OperandIdx < 2);
uint8_t Opcode = Instr.Opcode;
OperandType Type = getOperandTypes()[Opcode][OperandIdx];
switch (Type) {
case OT_Unset: {
OS << " Unsupported " << (OperandIdx ? "second" : "first") << " operand to";
auto OpcodeName = CallFrameString(Opcode, Arch);
if (!OpcodeName.empty())
OS << " " << OpcodeName;
else
OS << format(" Opcode %x", Opcode);
break;
}
case OT_None:
break;
case OT_Address:
OS << format(" %" PRIx64, Operand);
break;
case OT_Offset:
// The offsets are all encoded in a unsigned form, but in practice
// consumers use them signed. It's most certainly legacy due to
// the lack of signed variants in the first Dwarf standards.
OS << format(" %+" PRId64, int64_t(Operand));
break;
case OT_FactoredCodeOffset: // Always Unsigned
if (CodeAlignmentFactor)
OS << format(" %" PRId64, Operand * CodeAlignmentFactor);
else
OS << format(" %" PRId64 "*code_alignment_factor" , Operand);
break;
case OT_SignedFactDataOffset:
if (DataAlignmentFactor)
OS << format(" %" PRId64, int64_t(Operand) * DataAlignmentFactor);
else
OS << format(" %" PRId64 "*data_alignment_factor" , int64_t(Operand));
break;
case OT_UnsignedFactDataOffset:
if (DataAlignmentFactor)
OS << format(" %" PRId64, Operand * DataAlignmentFactor);
else
OS << format(" %" PRId64 "*data_alignment_factor" , Operand);
break;
case OT_Register:
OS << format(" reg%" PRId64, Operand);
break;
case OT_Expression:
assert(Instr.Expression && "missing DWARFExpression object");
OS << " ";
Instr.Expression->print(OS, MRI, nullptr, IsEH);
break;
}
}
void CFIProgram::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH,
unsigned IndentLevel) const {
for (const auto &Instr : Instructions) {
uint8_t Opcode = Instr.Opcode;
if (Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK)
Opcode &= DWARF_CFI_PRIMARY_OPCODE_MASK;
OS.indent(2 * IndentLevel);
OS << CallFrameString(Opcode, Arch) << ":";
for (unsigned i = 0; i < Instr.Ops.size(); ++i)
printOperand(OS, MRI, IsEH, Instr, i, Instr.Ops[i]);
OS << '\n';
}
}
void CIE::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH) const {
OS << format("%08x %08x %08x CIE", (uint32_t)Offset, (uint32_t)Length,
IsEH ? 0 : DW_CIE_ID)
<< "\n";
OS << format(" Version: %d\n", Version);
OS << " Augmentation: \"" << Augmentation << "\"\n";
if (Version >= 4) {
OS << format(" Address size: %u\n", (uint32_t)AddressSize);
OS << format(" Segment desc size: %u\n",
(uint32_t)SegmentDescriptorSize);
}
OS << format(" Code alignment factor: %u\n", (uint32_t)CodeAlignmentFactor);
OS << format(" Data alignment factor: %d\n", (int32_t)DataAlignmentFactor);
OS << format(" Return address column: %d\n", (int32_t)ReturnAddressRegister);
if (Personality)
OS << format(" Personality Address: %016" PRIx64 "\n", *Personality);
if (!AugmentationData.empty()) {
OS << " Augmentation data: ";
for (uint8_t Byte : AugmentationData)
OS << ' ' << hexdigit(Byte >> 4) << hexdigit(Byte & 0xf);
OS << "\n";
}
OS << "\n";
CFIs.dump(OS, MRI, IsEH);
OS << "\n";
}
void FDE::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH) const {
OS << format("%08x %08x %08x", (uint32_t)Offset, (uint32_t)Length,
(uint32_t)CIEPointer)
<< " FDE cie=";
if (LinkedCIE)
OS << format("%08x", (uint32_t)(LinkedCIE->getOffset()));
else
OS << "<invalid offset>";
OS << format(" pc=%08x...%08x\n", (uint32_t)InitialLocation,
(uint32_t)InitialLocation + (uint32_t)AddressRange);
if (LSDAAddress)
OS << format(" LSDA Address: %016" PRIx64 "\n", *LSDAAddress);
CFIs.dump(OS, MRI, IsEH);
OS << "\n";
}
DWARFDebugFrame::DWARFDebugFrame(Triple::ArchType Arch,
bool IsEH, uint64_t EHFrameAddress)
: Arch(Arch), IsEH(IsEH), EHFrameAddress(EHFrameAddress) {}
DWARFDebugFrame::~DWARFDebugFrame() = default;
static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data,
uint64_t Offset, int Length) {
errs() << "DUMP: ";
for (int i = 0; i < Length; ++i) {
uint8_t c = Data.getU8(&Offset);
errs().write_hex(c); errs() << " ";
}
errs() << "\n";
}
// This is a workaround for old compilers which do not allow
// noreturn attribute usage in lambdas. Once the support for those
// compilers are phased out, we can remove this and return back to
// a ReportError lambda: [StartOffset](const char *ErrorMsg).
static void LLVM_ATTRIBUTE_NORETURN ReportError(uint64_t StartOffset,
const char *ErrorMsg) {
std::string Str;
raw_string_ostream OS(Str);
OS << format(ErrorMsg, StartOffset);
OS.flush();
report_fatal_error(Str);
}
void DWARFDebugFrame::parse(DWARFDataExtractor Data) {
uint64_t Offset = 0;
DenseMap<uint64_t, CIE *> CIEs;
while (Data.isValidOffset(Offset)) {
uint64_t StartOffset = Offset;
bool IsDWARF64 = false;
uint64_t Length = Data.getRelocatedValue(4, &Offset);
uint64_t Id;
if (Length == dwarf::DW_LENGTH_DWARF64) {
// DWARF-64 is distinguished by the first 32 bits of the initial length
// field being 0xffffffff. Then, the next 64 bits are the actual entry
// length.
IsDWARF64 = true;
Length = Data.getRelocatedValue(8, &Offset);
}
// At this point, Offset points to the next field after Length.
// Length is the structure size excluding itself. Compute an offset one
// past the end of the structure (needed to know how many instructions to
// read).
uint64_t StartStructureOffset = Offset;
uint64_t EndStructureOffset = Offset + Length;
// The Id field's size depends on the DWARF format
Id = Data.getRelocatedValue((IsDWARF64 && !IsEH) ? 8 : 4, &Offset);
bool IsCIE =
((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID || (IsEH && !Id));
if (IsCIE) {
uint8_t Version = Data.getU8(&Offset);
const char *Augmentation = Data.getCStr(&Offset);
StringRef AugmentationString(Augmentation ? Augmentation : "");
uint8_t AddressSize = Version < 4 ? Data.getAddressSize() :
Data.getU8(&Offset);
Data.setAddressSize(AddressSize);
uint8_t SegmentDescriptorSize = Version < 4 ? 0 : Data.getU8(&Offset);
uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
uint64_t ReturnAddressRegister =
Version == 1 ? Data.getU8(&Offset) : Data.getULEB128(&Offset);
// Parse the augmentation data for EH CIEs
StringRef AugmentationData("");
uint32_t FDEPointerEncoding = DW_EH_PE_absptr;
uint32_t LSDAPointerEncoding = DW_EH_PE_omit;
Optional<uint64_t> Personality;
Optional<uint32_t> PersonalityEncoding;
if (IsEH) {
Optional<uint64_t> AugmentationLength;
uint64_t StartAugmentationOffset;
uint64_t EndAugmentationOffset;
// Walk the augmentation string to get all the augmentation data.
for (unsigned i = 0, e = AugmentationString.size(); i != e; ++i) {
switch (AugmentationString[i]) {
default:
ReportError(
StartOffset,
"Unknown augmentation character in entry at %" PRIx64);
case 'L':
LSDAPointerEncoding = Data.getU8(&Offset);
break;
case 'P': {
if (Personality)
ReportError(StartOffset,
"Duplicate personality in entry at %" PRIx64);
PersonalityEncoding = Data.getU8(&Offset);
Personality = Data.getEncodedPointer(
&Offset, *PersonalityEncoding,
EHFrameAddress ? EHFrameAddress + Offset : 0);
break;
}
case 'R':
FDEPointerEncoding = Data.getU8(&Offset);
break;
case 'S':
// Current frame is a signal trampoline.
break;
case 'z':
if (i)
ReportError(StartOffset,
"'z' must be the first character at %" PRIx64);
// Parse the augmentation length first. We only parse it if
// the string contains a 'z'.
AugmentationLength = Data.getULEB128(&Offset);
StartAugmentationOffset = Offset;
EndAugmentationOffset = Offset + *AugmentationLength;
break;
case 'B':
// B-Key is used for signing functions associated with this
// augmentation string
break;
}
}
if (AugmentationLength.hasValue()) {
if (Offset != EndAugmentationOffset)
ReportError(StartOffset,
"Parsing augmentation data at %" PRIx64 " failed");
AugmentationData = Data.getData().slice(StartAugmentationOffset,
EndAugmentationOffset);
}
}
auto Cie = std::make_unique<CIE>(
StartOffset, Length, Version, AugmentationString, AddressSize,
SegmentDescriptorSize, CodeAlignmentFactor, DataAlignmentFactor,
ReturnAddressRegister, AugmentationData, FDEPointerEncoding,
LSDAPointerEncoding, Personality, PersonalityEncoding, Arch);
CIEs[StartOffset] = Cie.get();
Entries.emplace_back(std::move(Cie));
} else {
// FDE
uint64_t CIEPointer = Id;
uint64_t InitialLocation = 0;
uint64_t AddressRange = 0;
Optional<uint64_t> LSDAAddress;
CIE *Cie = CIEs[IsEH ? (StartStructureOffset - CIEPointer) : CIEPointer];
if (IsEH) {
// The address size is encoded in the CIE we reference.
if (!Cie)
ReportError(StartOffset, "Parsing FDE data at %" PRIx64
" failed due to missing CIE");
if (auto Val = Data.getEncodedPointer(
&Offset, Cie->getFDEPointerEncoding(),
EHFrameAddress ? EHFrameAddress + Offset : 0)) {
InitialLocation = *Val;
}
if (auto Val = Data.getEncodedPointer(
&Offset, Cie->getFDEPointerEncoding(), 0)) {
AddressRange = *Val;
}
StringRef AugmentationString = Cie->getAugmentationString();
if (!AugmentationString.empty()) {
// Parse the augmentation length and data for this FDE.
uint64_t AugmentationLength = Data.getULEB128(&Offset);
uint64_t EndAugmentationOffset = Offset + AugmentationLength;
// Decode the LSDA if the CIE augmentation string said we should.
if (Cie->getLSDAPointerEncoding() != DW_EH_PE_omit) {
LSDAAddress = Data.getEncodedPointer(
&Offset, Cie->getLSDAPointerEncoding(),
EHFrameAddress ? Offset + EHFrameAddress : 0);
}
if (Offset != EndAugmentationOffset)
ReportError(StartOffset,
"Parsing augmentation data at %" PRIx64 " failed");
}
} else {
InitialLocation = Data.getRelocatedAddress(&Offset);
AddressRange = Data.getRelocatedAddress(&Offset);
}
Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer,
InitialLocation, AddressRange,
Cie, LSDAAddress, Arch));
}
if (Error E =
Entries.back()->cfis().parse(Data, &Offset, EndStructureOffset)) {
report_fatal_error(toString(std::move(E)));
}
if (Offset != EndStructureOffset)
ReportError(StartOffset,
"Parsing entry instructions at %" PRIx64 " failed");
}
}
FrameEntry *DWARFDebugFrame::getEntryAtOffset(uint64_t Offset) const {
auto It = partition_point(Entries, [=](const std::unique_ptr<FrameEntry> &E) {
return E->getOffset() < Offset;
});
if (It != Entries.end() && (*It)->getOffset() == Offset)
return It->get();
return nullptr;
}
void DWARFDebugFrame::dump(raw_ostream &OS, const MCRegisterInfo *MRI,
Optional<uint64_t> Offset) const {
if (Offset) {
if (auto *Entry = getEntryAtOffset(*Offset))
Entry->dump(OS, MRI, IsEH);
return;
}
OS << "\n";
for (const auto &Entry : Entries)
Entry->dump(OS, MRI, IsEH);
}
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