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llvm-mirror/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,
uint8_t &UnitType, bool &isUnitDWARF64) {
uint32_t AbbrOffset, Length;
uint8_t AddrSize = 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 {
UnitType = 0;
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::verifyUnitContents(DWARFUnit Unit) {
uint32_t NumUnitErrors = 0;
unsigned NumDies = Unit.getNumDIEs();
for (unsigned I = 0; I < NumDies; ++I) {
auto Die = Unit.getDIEAtIndex(I);
if (Die.getTag() == DW_TAG_null)
continue;
NumUnitErrors += verifyDieRanges(Die);
for (auto AttrValue : Die.attributes()) {
NumUnitErrors += verifyDebugInfoAttribute(Die, AttrValue);
NumUnitErrors += verifyDebugInfoForm(Die, AttrValue);
}
}
return NumUnitErrors == 0;
}
unsigned DWARFVerifier::verifyAbbrevSection(const DWARFDebugAbbrev *Abbrev) {
unsigned NumErrors = 0;
if (Abbrev) {
const DWARFAbbreviationDeclarationSet *AbbrDecls =
Abbrev->getAbbreviationDeclarationSet(0);
for (auto AbbrDecl : *AbbrDecls) {
SmallDenseSet<uint16_t> AttributeSet;
for (auto Attribute : AbbrDecl.attributes()) {
auto Result = AttributeSet.insert(Attribute.Attr);
if (!Result.second) {
OS << "Error: Abbreviation declaration contains multiple "
<< AttributeString(Attribute.Attr) << " attributes.\n";
AbbrDecl.dump(OS);
++NumErrors;
}
}
}
}
return NumErrors;
}
bool DWARFVerifier::handleDebugAbbrev() {
OS << "Verifying .debug_abbrev...\n";
const DWARFObject &DObj = DCtx.getDWARFObj();
bool noDebugAbbrev = DObj.getAbbrevSection().empty();
bool noDebugAbbrevDWO = DObj.getAbbrevDWOSection().empty();
if (noDebugAbbrev && noDebugAbbrevDWO) {
return true;
}
unsigned NumErrors = 0;
if (!noDebugAbbrev)
NumErrors += verifyAbbrevSection(DCtx.getDebugAbbrev());
if (!noDebugAbbrevDWO)
NumErrors += verifyAbbrevSection(DCtx.getDebugAbbrevDWO());
return NumErrors == 0;
}
bool DWARFVerifier::handleDebugInfo() {
OS << "Verifying .debug_info Unit Header Chain...\n";
const DWARFObject &DObj = DCtx.getDWARFObj();
DWARFDataExtractor DebugInfoData(DObj, DObj.getInfoSection(),
DCtx.isLittleEndian(), 0);
uint32_t NumDebugInfoErrors = 0;
uint32_t OffsetStart = 0, Offset = 0, UnitIdx = 0;
uint8_t UnitType = 0;
bool isUnitDWARF64 = false;
bool isHeaderChainValid = true;
bool hasDIE = DebugInfoData.isValidOffset(Offset);
while (hasDIE) {
OffsetStart = Offset;
if (!verifyUnitHeader(DebugInfoData, &Offset, UnitIdx, UnitType,
isUnitDWARF64)) {
isHeaderChainValid = false;
if (isUnitDWARF64)
break;
} else {
std::unique_ptr<DWARFUnit> Unit;
switch (UnitType) {
case dwarf::DW_UT_type:
case dwarf::DW_UT_split_type: {
DWARFUnitSection<DWARFTypeUnit> TUSection{};
Unit.reset(new DWARFTypeUnit(
DCtx, DObj.getInfoSection(), DCtx.getDebugAbbrev(),
&DObj.getRangeSection(), DObj.getStringSection(),
DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
DObj.getLineSection(), DCtx.isLittleEndian(), false, TUSection,
nullptr));
break;
}
case dwarf::DW_UT_skeleton:
case dwarf::DW_UT_split_compile:
case dwarf::DW_UT_compile:
case dwarf::DW_UT_partial:
// UnitType = 0 means that we are
// verifying a compile unit in DWARF v4.
case 0: {
DWARFUnitSection<DWARFCompileUnit> CUSection{};
Unit.reset(new DWARFCompileUnit(
DCtx, DObj.getInfoSection(), DCtx.getDebugAbbrev(),
&DObj.getRangeSection(), DObj.getStringSection(),
DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
DObj.getLineSection(), DCtx.isLittleEndian(), false, CUSection,
nullptr));
break;
}
default: { llvm_unreachable("Invalid UnitType."); }
}
Unit->extract(DebugInfoData, &OffsetStart);
if (!verifyUnitContents(*Unit))
++NumDebugInfoErrors;
}
hasDIE = DebugInfoData.isValidOffset(Offset);
++UnitIdx;
}
if (UnitIdx == 0 && !hasDIE) {
OS << "Warning: .debug_info is empty.\n";
isHeaderChainValid = true;
}
NumDebugInfoErrors += verifyDebugInfoReferences();
return (isHeaderChainValid && NumDebugInfoErrors == 0);
}
unsigned DWARFVerifier::verifyDieRanges(const DWARFDie &Die) {
unsigned NumErrors = 0;
for (auto Range : Die.getAddressRanges()) {
if (Range.LowPC >= Range.HighPC) {
++NumErrors;
OS << format("error: Invalid address range [0x%08" PRIx64
" - 0x%08" PRIx64 "].\n",
Range.LowPC, Range.HighPC);
}
}
return NumErrors;
}
unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
DWARFAttribute &AttrValue) {
const DWARFObject &DObj = DCtx.getDWARFObj();
unsigned NumErrors = 0;
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 >= DObj.getRangeSection().Data.size()) {
++NumErrors;
OS << "error: DW_AT_ranges offset is beyond .debug_ranges "
"bounds:\n";
Die.dump(OS, 0);
OS << "\n";
}
} else {
++NumErrors;
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 >= DObj.getLineSection().Data.size()) {
++NumErrors;
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 {
++NumErrors;
OS << "error: DIE has invalid DW_AT_stmt_list encoding:\n";
Die.dump(OS, 0);
OS << "\n";
}
break;
default:
break;
}
return NumErrors;
}
unsigned DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
DWARFAttribute &AttrValue) {
const DWARFObject &DObj = DCtx.getDWARFObj();
unsigned NumErrors = 0;
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) {
++NumErrors;
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 >= DObj.getInfoSection().Data.size()) {
++NumErrors;
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 >= DObj.getStringSection().size()) {
++NumErrors;
OS << "error: DW_FORM_strp offset beyond .debug_str bounds:\n";
Die.dump(OS, 0);
OS << "\n";
}
break;
}
default:
break;
}
return NumErrors;
}
unsigned 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";
unsigned NumErrors = 0;
for (auto Pair : ReferenceToDIEOffsets) {
auto Die = DCtx.getDIEForOffset(Pair.first);
if (Die)
continue;
++NumErrors;
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";
}
return NumErrors;
}
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.getDWARFObj().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;
}
unsigned DWARFVerifier::verifyAccelTable(const DWARFSection *AccelSection,
DataExtractor *StrData,
const char *SectionName) {
unsigned NumErrors = 0;
DWARFDataExtractor AccelSectionData(DCtx.getDWARFObj(), *AccelSection,
DCtx.isLittleEndian(), 0);
DWARFAcceleratorTable AccelTable(AccelSectionData, *StrData);
OS << "Verifying " << SectionName << "...\n";
// Verify that the fixed part of the header is not too short.
if (!AccelSectionData.isValidOffset(AccelTable.getSizeHdr())) {
OS << "\terror: Section is too small to fit a section header.\n";
return 1;
}
// Verify that the section is not too short.
if (!AccelTable.extract()) {
OS << "\terror: Section is smaller than size described in section header.\n";
return 1;
}
// Verify that all buckets have a valid hash index or are empty.
uint32_t NumBuckets = AccelTable.getNumBuckets();
uint32_t NumHashes = AccelTable.getNumHashes();
uint32_t BucketsOffset =
AccelTable.getSizeHdr() + AccelTable.getHeaderDataLength();
uint32_t HashesBase = BucketsOffset + NumBuckets * 4;
uint32_t OffsetsBase = HashesBase + NumHashes * 4;
for (uint32_t BucketIdx = 0; BucketIdx < NumBuckets; ++BucketIdx) {
uint32_t HashIdx = AccelSectionData.getU32(&BucketsOffset);
if (HashIdx >= NumHashes && HashIdx != UINT32_MAX) {
OS << format("\terror: Bucket[%d] has invalid hash index: %u.\n", BucketIdx,
HashIdx);
++NumErrors;
}
}
uint32_t NumAtoms = AccelTable.getAtomsDesc().size();
if (NumAtoms == 0) {
OS << "\terror: no atoms; failed to read HashData.\n";
return 1;
}
if (!AccelTable.validateForms()) {
OS << "\terror: unsupported form; failed to read HashData.\n";
return 1;
}
for (uint32_t HashIdx = 0; HashIdx < NumHashes; ++HashIdx) {
uint32_t HashOffset = HashesBase + 4 * HashIdx;
uint32_t DataOffset = OffsetsBase + 4 * HashIdx;
uint32_t Hash = AccelSectionData.getU32(&HashOffset);
uint32_t HashDataOffset = AccelSectionData.getU32(&DataOffset);
if (!AccelSectionData.isValidOffsetForDataOfSize(HashDataOffset,
sizeof(uint64_t))) {
OS << format("\terror: Hash[%d] has invalid HashData offset: 0x%08x.\n",
HashIdx, HashDataOffset);
++NumErrors;
}
uint32_t StrpOffset;
uint32_t StringOffset;
uint32_t StringCount = 0;
uint32_t DieOffset = dwarf::DW_INVALID_OFFSET;
while ((StrpOffset = AccelSectionData.getU32(&HashDataOffset)) != 0) {
const uint32_t NumHashDataObjects =
AccelSectionData.getU32(&HashDataOffset);
for (uint32_t HashDataIdx = 0; HashDataIdx < NumHashDataObjects;
++HashDataIdx) {
DieOffset = AccelTable.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(
"\terror: %s Bucket[%d] Hash[%d] = 0x%08x "
"Str[%u] = 0x%08x "
"DIE[%d] = 0x%08x is not a valid DIE offset for \"%s\".\n",
SectionName, BucketIdx, HashIdx, Hash, StringCount, StrpOffset,
HashDataIdx, DieOffset, Name);
++NumErrors;
}
}
++StringCount;
}
}
return NumErrors;
}
bool DWARFVerifier::handleAccelTables() {
const DWARFObject &D = DCtx.getDWARFObj();
DataExtractor StrData(D.getStringSection(), DCtx.isLittleEndian(), 0);
unsigned NumErrors = 0;
if (!D.getAppleNamesSection().Data.empty())
NumErrors +=
verifyAccelTable(&D.getAppleNamesSection(), &StrData, ".apple_names");
if (!D.getAppleTypesSection().Data.empty())
NumErrors +=
verifyAccelTable(&D.getAppleTypesSection(), &StrData, ".apple_types");
if (!D.getAppleNamespacesSection().Data.empty())
NumErrors += verifyAccelTable(&D.getAppleNamespacesSection(), &StrData,
".apple_namespaces");
if (!D.getAppleObjCSection().Data.empty())
NumErrors +=
verifyAccelTable(&D.getAppleObjCSection(), &StrData, ".apple_objc");
return NumErrors == 0;
}
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