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llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp

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//===- DWARFDebugFrame.h - Parsing of .debug_frame ------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#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/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(DataExtractor Data, uint32_t *Offset,
uint32_t EndOffset) {
while (*Offset < EndOffset) {
uint8_t Opcode = Data.getU8(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 make_error<StringError>(
"Invalid primary CFI opcode",
std::make_error_code(std::errc::illegal_byte_sequence));
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 make_error<StringError>(
"Invalid extended CFI opcode",
std::make_error_code(std::errc::illegal_byte_sequence));
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.getAddress(Offset));
break;
case DW_CFA_advance_loc1:
// Operands: 1-byte delta
addInstruction(Opcode, Data.getU8(Offset));
break;
case DW_CFA_advance_loc2:
// Operands: 2-byte delta
addInstruction(Opcode, Data.getU16(Offset));
break;
case DW_CFA_advance_loc4:
// Operands: 4-byte delta
addInstruction(Opcode, Data.getU32(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(), dwarf::DWARF_VERSION);
*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(), dwarf::DWARF_VERSION);
*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);
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, 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) << ":";
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,
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: %08x\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 FDE ", (uint32_t)Offset, (uint32_t)Length,
(int32_t)LinkedCIEOffset);
OS << format("cie=%08x pc=%08x...%08x\n", (int32_t)LinkedCIEOffset,
(uint32_t)InitialLocation,
(uint32_t)InitialLocation + (uint32_t)AddressRange);
if (LSDAAddress)
OS << format(" LSDA Address: %08x\n", *LSDAAddress);
CFIs.dump(OS, MRI, IsEH);
OS << "\n";
}
DWARFDebugFrame::DWARFDebugFrame(bool IsEH, uint64_t EHFrameAddress)
: IsEH(IsEH), EHFrameAddress(EHFrameAddress) {}
DWARFDebugFrame::~DWARFDebugFrame() = default;
static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data,
uint32_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(uint32_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) {
uint32_t Offset = 0;
DenseMap<uint32_t, CIE *> CIEs;
while (Data.isValidOffset(Offset)) {
uint32_t StartOffset = Offset;
bool IsDWARF64 = false;
uint64_t Length = Data.getU32(&Offset);
uint64_t Id;
if (Length == UINT32_MAX) {
// 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.getU64(&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).
// TODO: For honest DWARF64 support, DataExtractor will have to treat
// offset_ptr as uint64_t*
uint32_t StartStructureOffset = Offset;
uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length);
// The Id field's size depends on the DWARF format
Id = Data.getUnsigned(&Offset, (IsDWARF64 && !IsEH) ? 8 : 4);
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 = Data.getULEB128(&Offset);
// Parse the augmentation data for EH CIEs
StringRef AugmentationData("");
uint32_t FDEPointerEncoding = DW_EH_PE_omit;
uint32_t LSDAPointerEncoding = DW_EH_PE_omit;
Optional<uint64_t> Personality;
Optional<uint32_t> PersonalityEncoding;
if (IsEH) {
Optional<uint64_t> AugmentationLength;
uint32_t StartAugmentationOffset;
uint32_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 %lx");
case 'L':
LSDAPointerEncoding = Data.getU8(&Offset);
break;
case 'P': {
if (Personality)
ReportError(StartOffset,
"Duplicate personality in entry at %lx");
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 %lx");
// Parse the augmentation length first. We only parse it if
// the string contains a 'z'.
AugmentationLength = Data.getULEB128(&Offset);
StartAugmentationOffset = Offset;
EndAugmentationOffset = Offset +
static_cast<uint32_t>(*AugmentationLength);
}
}
if (AugmentationLength.hasValue()) {
if (Offset != EndAugmentationOffset)
ReportError(StartOffset, "Parsing augmentation data at %lx failed");
AugmentationData = Data.getData().slice(StartAugmentationOffset,
EndAugmentationOffset);
}
}
auto Cie = llvm::make_unique<CIE>(
StartOffset, Length, Version, AugmentationString, AddressSize,
SegmentDescriptorSize, CodeAlignmentFactor, DataAlignmentFactor,
ReturnAddressRegister, AugmentationData, FDEPointerEncoding,
LSDAPointerEncoding, Personality, PersonalityEncoding);
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 %lx 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);
uint32_t EndAugmentationOffset =
Offset + static_cast<uint32_t>(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 %lx failed");
}
} else {
InitialLocation = Data.getAddress(&Offset);
AddressRange = Data.getAddress(&Offset);
}
Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer,
InitialLocation, AddressRange,
Cie, LSDAAddress));
}
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 %lx failed");
}
}
FrameEntry *DWARFDebugFrame::getEntryAtOffset(uint64_t Offset) const {
auto It =
std::lower_bound(Entries.begin(), Entries.end(), Offset,
[](const std::unique_ptr<FrameEntry> &E,
uint64_t Offset) { 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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