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

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//===- DWARFVerifier.cpp --------------------------------------------------===//
//
// 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/DWARFVerifier.h"
#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
#include "llvm/DebugInfo/DWARF/DWARFDie.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
#include <set>
#include <vector>
using namespace llvm;
using namespace dwarf;
using namespace object;
bool DWARFVerifier::verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
uint32_t *Offset, unsigned UnitIndex,
bool &isUnitDWARF64) {
uint32_t AbbrOffset, Length;
uint8_t AddrSize = 0, UnitType = 0;
uint16_t Version;
bool Success = true;
bool ValidLength = false;
bool ValidVersion = false;
bool ValidAddrSize = false;
bool ValidType = true;
bool ValidAbbrevOffset = true;
uint32_t OffsetStart = *Offset;
Length = DebugInfoData.getU32(Offset);
if (Length == UINT32_MAX) {
isUnitDWARF64 = true;
OS << format(
"Unit[%d] is in 64-bit DWARF format; cannot verify from this point.\n",
UnitIndex);
return false;
}
Version = DebugInfoData.getU16(Offset);
if (Version >= 5) {
UnitType = DebugInfoData.getU8(Offset);
AddrSize = DebugInfoData.getU8(Offset);
AbbrOffset = DebugInfoData.getU32(Offset);
ValidType = DWARFUnit::isValidUnitType(UnitType);
} else {
AbbrOffset = DebugInfoData.getU32(Offset);
AddrSize = DebugInfoData.getU8(Offset);
}
if (!DCtx.getDebugAbbrev()->getAbbreviationDeclarationSet(AbbrOffset))
ValidAbbrevOffset = false;
ValidLength = DebugInfoData.isValidOffset(OffsetStart + Length + 3);
ValidVersion = DWARFContext::isSupportedVersion(Version);
ValidAddrSize = AddrSize == 4 || AddrSize == 8;
if (!ValidLength || !ValidVersion || !ValidAddrSize || !ValidAbbrevOffset ||
!ValidType) {
Success = false;
OS << format("Units[%d] - start offset: 0x%08x \n", UnitIndex, OffsetStart);
if (!ValidLength)
OS << "\tError: The length for this unit is too "
"large for the .debug_info provided.\n";
if (!ValidVersion)
OS << "\tError: The 16 bit unit header version is not valid.\n";
if (!ValidType)
OS << "\tError: The unit type encoding is not valid.\n";
if (!ValidAbbrevOffset)
OS << "\tError: The offset into the .debug_abbrev section is "
"not valid.\n";
if (!ValidAddrSize)
OS << "\tError: The address size is unsupported.\n";
}
*Offset = OffsetStart + Length + 4;
return Success;
}
bool DWARFVerifier::handleDebugInfoUnitHeaderChain() {
OS << "Verifying .debug_info Unit Header Chain...\n";
DWARFDataExtractor DebugInfoData(DCtx.getInfoSection(), DCtx.isLittleEndian(),
0);
uint32_t Offset = 0, UnitIdx = 0;
bool isUnitDWARF64 = false;
bool Success = true;
bool hasDIE = DebugInfoData.isValidOffset(Offset);
while (hasDIE) {
if (!verifyUnitHeader(DebugInfoData, &Offset, UnitIdx, isUnitDWARF64)) {
Success = false;
if (isUnitDWARF64)
break;
}
hasDIE = DebugInfoData.isValidOffset(Offset);
++UnitIdx;
}
if (UnitIdx == 0 && !hasDIE) {
OS << "Warning: .debug_info is empty.\n";
Success = true;
}
return Success;
}
void DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
DWARFAttribute &AttrValue) {
const auto Attr = AttrValue.Attr;
switch (Attr) {
case DW_AT_ranges:
// Make sure the offset in the DW_AT_ranges attribute is valid.
if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
if (*SectionOffset >= DCtx.getRangeSection().Data.size()) {
++NumDebugInfoErrors;
OS << "error: DW_AT_ranges offset is beyond .debug_ranges "
"bounds:\n";
Die.dump(OS, 0);
OS << "\n";
}
} else {
++NumDebugInfoErrors;
OS << "error: DIE has invalid DW_AT_ranges encoding:\n";
Die.dump(OS, 0);
OS << "\n";
}
break;
case DW_AT_stmt_list:
// Make sure the offset in the DW_AT_stmt_list attribute is valid.
if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
if (*SectionOffset >= DCtx.getLineSection().Data.size()) {
++NumDebugInfoErrors;
OS << "error: DW_AT_stmt_list offset is beyond .debug_line "
"bounds: "
<< format("0x%08" PRIx32, *SectionOffset) << "\n";
Die.dump(OS, 0);
OS << "\n";
}
} else {
++NumDebugInfoErrors;
OS << "error: DIE has invalid DW_AT_stmt_list encoding:\n";
Die.dump(OS, 0);
OS << "\n";
}
break;
default:
break;
}
}
void DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
DWARFAttribute &AttrValue) {
const auto Form = AttrValue.Value.getForm();
switch (Form) {
case DW_FORM_ref1:
case DW_FORM_ref2:
case DW_FORM_ref4:
case DW_FORM_ref8:
case DW_FORM_ref_udata: {
// Verify all CU relative references are valid CU offsets.
Optional<uint64_t> RefVal = AttrValue.Value.getAsReference();
assert(RefVal);
if (RefVal) {
auto DieCU = Die.getDwarfUnit();
auto CUSize = DieCU->getNextUnitOffset() - DieCU->getOffset();
auto CUOffset = AttrValue.Value.getRawUValue();
if (CUOffset >= CUSize) {
++NumDebugInfoErrors;
OS << "error: " << FormEncodingString(Form) << " CU offset "
<< format("0x%08" PRIx32, CUOffset)
<< " is invalid (must be less than CU size of "
<< format("0x%08" PRIx32, CUSize) << "):\n";
Die.dump(OS, 0);
OS << "\n";
} else {
// Valid reference, but we will verify it points to an actual
// DIE later.
ReferenceToDIEOffsets[*RefVal].insert(Die.getOffset());
}
}
break;
}
case DW_FORM_ref_addr: {
// Verify all absolute DIE references have valid offsets in the
// .debug_info section.
Optional<uint64_t> RefVal = AttrValue.Value.getAsReference();
assert(RefVal);
if (RefVal) {
if (*RefVal >= DCtx.getInfoSection().Data.size()) {
++NumDebugInfoErrors;
OS << "error: DW_FORM_ref_addr offset beyond .debug_info "
"bounds:\n";
Die.dump(OS, 0);
OS << "\n";
} else {
// Valid reference, but we will verify it points to an actual
// DIE later.
ReferenceToDIEOffsets[*RefVal].insert(Die.getOffset());
}
}
break;
}
case DW_FORM_strp: {
auto SecOffset = AttrValue.Value.getAsSectionOffset();
assert(SecOffset); // DW_FORM_strp is a section offset.
if (SecOffset && *SecOffset >= DCtx.getStringSection().size()) {
++NumDebugInfoErrors;
OS << "error: DW_FORM_strp offset beyond .debug_str bounds:\n";
Die.dump(OS, 0);
OS << "\n";
}
break;
}
default:
break;
}
}
void DWARFVerifier::verifyDebugInfoReferences() {
// Take all references and make sure they point to an actual DIE by
// getting the DIE by offset and emitting an error
OS << "Verifying .debug_info references...\n";
for (auto Pair : ReferenceToDIEOffsets) {
auto Die = DCtx.getDIEForOffset(Pair.first);
if (Die)
continue;
++NumDebugInfoErrors;
OS << "error: invalid DIE reference " << format("0x%08" PRIx64, Pair.first)
<< ". Offset is in between DIEs:\n";
for (auto Offset : Pair.second) {
auto ReferencingDie = DCtx.getDIEForOffset(Offset);
ReferencingDie.dump(OS, 0);
OS << "\n";
}
OS << "\n";
}
}
bool DWARFVerifier::handleDebugInfo() {
NumDebugInfoErrors = 0;
OS << "Verifying .debug_info...\n";
for (const auto &CU : DCtx.compile_units()) {
unsigned NumDies = CU->getNumDIEs();
for (unsigned I = 0; I < NumDies; ++I) {
auto Die = CU->getDIEAtIndex(I);
const auto Tag = Die.getTag();
if (Tag == DW_TAG_null)
continue;
for (auto AttrValue : Die.attributes()) {
verifyDebugInfoAttribute(Die, AttrValue);
verifyDebugInfoForm(Die, AttrValue);
}
}
}
verifyDebugInfoReferences();
return NumDebugInfoErrors == 0;
}
void DWARFVerifier::verifyDebugLineStmtOffsets() {
std::map<uint64_t, DWARFDie> StmtListToDie;
for (const auto &CU : DCtx.compile_units()) {
auto Die = CU->getUnitDIE();
// Get the attribute value as a section offset. No need to produce an
// error here if the encoding isn't correct because we validate this in
// the .debug_info verifier.
auto StmtSectionOffset = toSectionOffset(Die.find(DW_AT_stmt_list));
if (!StmtSectionOffset)
continue;
const uint32_t LineTableOffset = *StmtSectionOffset;
auto LineTable = DCtx.getLineTableForUnit(CU.get());
if (LineTableOffset < DCtx.getLineSection().Data.size()) {
if (!LineTable) {
++NumDebugLineErrors;
OS << "error: .debug_line[" << format("0x%08" PRIx32, LineTableOffset)
<< "] was not able to be parsed for CU:\n";
Die.dump(OS, 0);
OS << '\n';
continue;
}
} else {
// Make sure we don't get a valid line table back if the offset is wrong.
assert(LineTable == nullptr);
// Skip this line table as it isn't valid. No need to create an error
// here because we validate this in the .debug_info verifier.
continue;
}
auto Iter = StmtListToDie.find(LineTableOffset);
if (Iter != StmtListToDie.end()) {
++NumDebugLineErrors;
OS << "error: two compile unit DIEs, "
<< format("0x%08" PRIx32, Iter->second.getOffset()) << " and "
<< format("0x%08" PRIx32, Die.getOffset())
<< ", have the same DW_AT_stmt_list section offset:\n";
Iter->second.dump(OS, 0);
Die.dump(OS, 0);
OS << '\n';
// Already verified this line table before, no need to do it again.
continue;
}
StmtListToDie[LineTableOffset] = Die;
}
}
void DWARFVerifier::verifyDebugLineRows() {
for (const auto &CU : DCtx.compile_units()) {
auto Die = CU->getUnitDIE();
auto LineTable = DCtx.getLineTableForUnit(CU.get());
// If there is no line table we will have created an error in the
// .debug_info verifier or in verifyDebugLineStmtOffsets().
if (!LineTable)
continue;
uint32_t MaxFileIndex = LineTable->Prologue.FileNames.size();
uint64_t PrevAddress = 0;
uint32_t RowIndex = 0;
for (const auto &Row : LineTable->Rows) {
if (Row.Address < PrevAddress) {
++NumDebugLineErrors;
OS << "error: .debug_line["
<< format("0x%08" PRIx32,
*toSectionOffset(Die.find(DW_AT_stmt_list)))
<< "] row[" << RowIndex
<< "] decreases in address from previous row:\n";
DWARFDebugLine::Row::dumpTableHeader(OS);
if (RowIndex > 0)
LineTable->Rows[RowIndex - 1].dump(OS);
Row.dump(OS);
OS << '\n';
}
if (Row.File > MaxFileIndex) {
++NumDebugLineErrors;
OS << "error: .debug_line["
<< format("0x%08" PRIx32,
*toSectionOffset(Die.find(DW_AT_stmt_list)))
<< "][" << RowIndex << "] has invalid file index " << Row.File
<< " (valid values are [1," << MaxFileIndex << "]):\n";
DWARFDebugLine::Row::dumpTableHeader(OS);
Row.dump(OS);
OS << '\n';
}
if (Row.EndSequence)
PrevAddress = 0;
else
PrevAddress = Row.Address;
++RowIndex;
}
}
}
bool DWARFVerifier::handleDebugLine() {
NumDebugLineErrors = 0;
OS << "Verifying .debug_line...\n";
verifyDebugLineStmtOffsets();
verifyDebugLineRows();
return NumDebugLineErrors == 0;
}
bool DWARFVerifier::handleAppleNames() {
NumAppleNamesErrors = 0;
DWARFDataExtractor AppleNamesSection(DCtx.getAppleNamesSection(),
DCtx.isLittleEndian(), 0);
DataExtractor StrData(DCtx.getStringSection(), DCtx.isLittleEndian(), 0);
DWARFAcceleratorTable AppleNames(AppleNamesSection, StrData);
if (!AppleNames.extract()) {
return true;
}
OS << "Verifying .apple_names...\n";
// Verify that all buckets have a valid hash index or are empty.
uint32_t NumBuckets = AppleNames.getNumBuckets();
uint32_t NumHashes = AppleNames.getNumHashes();
uint32_t BucketsOffset =
AppleNames.getSizeHdr() + AppleNames.getHeaderDataLength();
uint32_t HashesBase = BucketsOffset + NumBuckets * 4;
uint32_t OffsetsBase = HashesBase + NumHashes * 4;
for (uint32_t BucketIdx = 0; BucketIdx < NumBuckets; ++BucketIdx) {
uint32_t HashIdx = AppleNamesSection.getU32(&BucketsOffset);
if (HashIdx >= NumHashes && HashIdx != UINT32_MAX) {
OS << format("error: Bucket[%d] has invalid hash index: %u\n", BucketIdx,
HashIdx);
++NumAppleNamesErrors;
}
}
uint32_t NumAtoms = AppleNames.getAtomsDesc().size();
if (NumAtoms == 0) {
OS << "error: no atoms; failed to read HashData\n";
++NumAppleNamesErrors;
return false;
}
if (!AppleNames.validateForms()) {
OS << "error: unsupported form; failed to read HashData\n";
++NumAppleNamesErrors;
return false;
}
for (uint32_t HashIdx = 0; HashIdx < NumHashes; ++HashIdx) {
uint32_t HashOffset = HashesBase + 4 * HashIdx;
uint32_t DataOffset = OffsetsBase + 4 * HashIdx;
uint32_t Hash = AppleNamesSection.getU32(&HashOffset);
uint32_t HashDataOffset = AppleNamesSection.getU32(&DataOffset);
if (!AppleNamesSection.isValidOffsetForDataOfSize(HashDataOffset,
sizeof(uint64_t))) {
OS << format("error: Hash[%d] has invalid HashData offset: 0x%08x\n",
HashIdx, HashDataOffset);
++NumAppleNamesErrors;
}
uint32_t StrpOffset;
uint32_t StringOffset;
uint32_t StringCount = 0;
uint32_t DieOffset = dwarf::DW_INVALID_OFFSET;
while ((StrpOffset = AppleNamesSection.getU32(&HashDataOffset)) != 0) {
const uint32_t NumHashDataObjects =
AppleNamesSection.getU32(&HashDataOffset);
for (uint32_t HashDataIdx = 0; HashDataIdx < NumHashDataObjects;
++HashDataIdx) {
DieOffset = AppleNames.readAtoms(HashDataOffset);
if (!DCtx.getDIEForOffset(DieOffset)) {
const uint32_t BucketIdx =
NumBuckets ? (Hash % NumBuckets) : UINT32_MAX;
StringOffset = StrpOffset;
const char *Name = StrData.getCStr(&StringOffset);
if (!Name)
Name = "<NULL>";
OS << format(
"error: .apple_names Bucket[%d] Hash[%d] = 0x%08x "
"Str[%u] = 0x%08x "
"DIE[%d] = 0x%08x is not a valid DIE offset for \"%s\".\n",
BucketIdx, HashIdx, Hash, StringCount, StrpOffset, HashDataIdx,
DieOffset, Name);
++NumAppleNamesErrors;
}
}
++StringCount;
}
}
return NumAppleNamesErrors == 0;
}
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