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llvm-project/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
Pavel Labath c9f07b06a1 DWARFVerifier: validate information in name index entries 
Summary:
This patch add checks to verify that the information in the name index
entries is consistent with the debug_info section. Specifically, we
check that entries point to valid DIEs, and their names, tags, and
compile units match the information in the debug_info sections.

These checks are only run if the previous checks did not find any errors
in the name index headers. Attempting to proceed with the checks anyway
would likely produce a lot of spurious errors and the verification code
would need to be very careful to avoid crashing.

I also add a couple of more checks to the abbreviation-validation code
to verify that some attributes are always present (an index without a
DW_IDX_die_offset attribute is fairly useless).

The entry verification works only on indexes without any type units - I
haven't attempted to extend it to type units, as we don't even have a
DWARF v5-compatible type unit generator at the moment.

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45323

llvm-svn: 329392
2018-04-06 13:34:12 +00:00

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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/ADT/SmallSet.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/DWARFExpression.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/Support/DJB.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
#include <set>
#include <vector>
using namespace llvm;
using namespace dwarf;
using namespace object;
DWARFVerifier::DieRangeInfo::address_range_iterator
DWARFVerifier::DieRangeInfo::insert(const DWARFAddressRange &R) {
auto Begin = Ranges.begin();
auto End = Ranges.end();
auto Pos = std::lower_bound(Begin, End, R);
if (Pos != End) {
if (Pos->intersects(R))
return Pos;
if (Pos != Begin) {
auto Iter = Pos - 1;
if (Iter->intersects(R))
return Iter;
}
}
Ranges.insert(Pos, R);
return Ranges.end();
}
DWARFVerifier::DieRangeInfo::die_range_info_iterator
DWARFVerifier::DieRangeInfo::insert(const DieRangeInfo &RI) {
auto End = Children.end();
auto Iter = Children.begin();
while (Iter != End) {
if (Iter->intersects(RI))
return Iter;
++Iter;
}
Children.insert(RI);
return Children.end();
}
bool DWARFVerifier::DieRangeInfo::contains(const DieRangeInfo &RHS) const {
// Both list of ranges are sorted so we can make this fast.
if (Ranges.empty() || RHS.Ranges.empty())
return false;
// Since the ranges are sorted we can advance where we start searching with
// this object's ranges as we traverse RHS.Ranges.
auto End = Ranges.end();
auto Iter = findRange(RHS.Ranges.front());
// Now linearly walk the ranges in this object and see if they contain each
// ranges from RHS.Ranges.
for (const auto &R : RHS.Ranges) {
while (Iter != End) {
if (Iter->contains(R))
break;
++Iter;
}
if (Iter == End)
return false;
}
return true;
}
bool DWARFVerifier::DieRangeInfo::intersects(const DieRangeInfo &RHS) const {
if (Ranges.empty() || RHS.Ranges.empty())
return false;
auto End = Ranges.end();
auto Iter = findRange(RHS.Ranges.front());
for (const auto &R : RHS.Ranges) {
if(Iter == End)
return false;
if (R.HighPC <= Iter->LowPC)
continue;
while (Iter != End) {
if (Iter->intersects(R))
return true;
++Iter;
}
}
return false;
}
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 = dwarf::isUnitType(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;
error() << format("Units[%d] - start offset: 0x%08x \n", UnitIndex,
OffsetStart);
if (!ValidLength)
note() << "The length for this unit is too "
"large for the .debug_info provided.\n";
if (!ValidVersion)
note() << "The 16 bit unit header version is not valid.\n";
if (!ValidType)
note() << "The unit type encoding is not valid.\n";
if (!ValidAbbrevOffset)
note() << "The offset into the .debug_abbrev section is "
"not valid.\n";
if (!ValidAddrSize)
note() << "The address size is unsupported.\n";
}
*Offset = OffsetStart + Length + 4;
return Success;
}
bool DWARFVerifier::verifyUnitContents(DWARFUnit Unit, uint8_t UnitType) {
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;
for (auto AttrValue : Die.attributes()) {
NumUnitErrors += verifyDebugInfoAttribute(Die, AttrValue);
NumUnitErrors += verifyDebugInfoForm(Die, AttrValue);
}
}
DWARFDie Die = Unit.getUnitDIE(/* ExtractUnitDIEOnly = */ false);
if (!Die) {
error() << "Compilation unit without DIE.\n";
NumUnitErrors++;
return NumUnitErrors == 0;
}
if (!dwarf::isUnitType(Die.getTag())) {
error() << "Compilation unit root DIE is not a unit DIE: "
<< dwarf::TagString(Die.getTag()) << ".\n";
NumUnitErrors++;
}
if (UnitType != 0 &&
!DWARFUnit::isMatchingUnitTypeAndTag(UnitType, Die.getTag())) {
error() << "Compilation unit type (" << dwarf::UnitTypeString(UnitType)
<< ") and root DIE (" << dwarf::TagString(Die.getTag())
<< ") do not match.\n";
NumUnitErrors++;
}
DieRangeInfo RI;
NumUnitErrors += verifyDieRanges(Die, RI);
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) {
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);
DWARFUnitSection<DWARFTypeUnit> TUSection{};
DWARFUnitSection<DWARFCompileUnit> CUSection{};
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: {
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: {
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, UnitType))
++NumDebugInfoErrors;
}
hasDIE = DebugInfoData.isValidOffset(Offset);
++UnitIdx;
}
if (UnitIdx == 0 && !hasDIE) {
warn() << ".debug_info is empty.\n";
isHeaderChainValid = true;
}
NumDebugInfoErrors += verifyDebugInfoReferences();
return (isHeaderChainValid && NumDebugInfoErrors == 0);
}
unsigned DWARFVerifier::verifyDieRanges(const DWARFDie &Die,
DieRangeInfo &ParentRI) {
unsigned NumErrors = 0;
if (!Die.isValid())
return NumErrors;
DWARFAddressRangesVector Ranges = Die.getAddressRanges();
// Build RI for this DIE and check that ranges within this DIE do not
// overlap.
DieRangeInfo RI(Die);
for (auto Range : Ranges) {
if (!Range.valid()) {
++NumErrors;
error() << "Invalid address range " << Range << "\n";
continue;
}
// Verify that ranges don't intersect.
const auto IntersectingRange = RI.insert(Range);
if (IntersectingRange != RI.Ranges.end()) {
++NumErrors;
error() << "DIE has overlapping address ranges: " << Range << " and "
<< *IntersectingRange << "\n";
break;
}
}
// Verify that children don't intersect.
const auto IntersectingChild = ParentRI.insert(RI);
if (IntersectingChild != ParentRI.Children.end()) {
++NumErrors;
error() << "DIEs have overlapping address ranges:";
Die.dump(OS, 0);
IntersectingChild->Die.dump(OS, 0);
OS << "\n";
}
// Verify that ranges are contained within their parent.
bool ShouldBeContained = !Ranges.empty() && !ParentRI.Ranges.empty() &&
!(Die.getTag() == DW_TAG_subprogram &&
ParentRI.Die.getTag() == DW_TAG_subprogram);
if (ShouldBeContained && !ParentRI.contains(RI)) {
++NumErrors;
error() << "DIE address ranges are not "
"contained in its parent's ranges:";
Die.dump(OS, 0);
ParentRI.Die.dump(OS, 0);
OS << "\n";
}
// Recursively check children.
for (DWARFDie Child : Die)
NumErrors += verifyDieRanges(Child, RI);
return NumErrors;
}
unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
DWARFAttribute &AttrValue) {
unsigned NumErrors = 0;
auto ReportError = [&](const Twine &TitleMsg) {
++NumErrors;
error() << TitleMsg << '\n';
Die.dump(OS, 0, DumpOpts);
OS << "\n";
};
const DWARFObject &DObj = DCtx.getDWARFObj();
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())
ReportError("DW_AT_ranges offset is beyond .debug_ranges bounds:");
break;
}
ReportError("DIE has invalid DW_AT_ranges encoding:");
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())
ReportError("DW_AT_stmt_list offset is beyond .debug_line bounds: " +
llvm::formatv("{0:x8}", *SectionOffset));
break;
}
ReportError("DIE has invalid DW_AT_stmt_list encoding:");
break;
case DW_AT_location: {
auto VerifyLocation = [&](StringRef D) {
DWARFUnit *U = Die.getDwarfUnit();
DataExtractor Data(D, DCtx.isLittleEndian(), 0);
DWARFExpression Expression(Data, U->getVersion(),
U->getAddressByteSize());
bool Error = llvm::any_of(Expression, [](DWARFExpression::Operation &Op) {
return Op.isError();
});
if (Error)
ReportError("DIE contains invalid DWARF expression:");
};
if (Optional<ArrayRef<uint8_t>> Expr = AttrValue.Value.getAsBlock()) {
// Verify inlined location.
VerifyLocation(llvm::toStringRef(*Expr));
} else if (auto LocOffset = AttrValue.Value.getAsUnsignedConstant()) {
// Verify location list.
if (auto DebugLoc = DCtx.getDebugLoc())
if (auto LocList = DebugLoc->getLocationListAtOffset(*LocOffset))
for (const auto &Entry : LocList->Entries)
VerifyLocation({Entry.Loc.data(), Entry.Loc.size()});
}
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;
error() << FormEncodingString(Form) << " CU offset "
<< format("0x%08" PRIx64, CUOffset)
<< " is invalid (must be less than CU size of "
<< format("0x%08" PRIx32, CUSize) << "):\n";
Die.dump(OS, 0, DumpOpts);
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;
error() << "DW_FORM_ref_addr offset beyond .debug_info "
"bounds:\n";
Die.dump(OS, 0, DumpOpts);
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;
error() << "DW_FORM_strp offset beyond .debug_str bounds:\n";
Die.dump(OS, 0, DumpOpts);
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;
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, DumpOpts);
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;
error() << ".debug_line[" << format("0x%08" PRIx32, LineTableOffset)
<< "] was not able to be parsed for CU:\n";
Die.dump(OS, 0, DumpOpts);
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;
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, DumpOpts);
Die.dump(OS, 0, DumpOpts);
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;
// Verify prologue.
uint32_t MaxFileIndex = LineTable->Prologue.FileNames.size();
uint32_t MaxDirIndex = LineTable->Prologue.IncludeDirectories.size();
uint32_t FileIndex = 1;
StringMap<uint16_t> FullPathMap;
for (const auto &FileName : LineTable->Prologue.FileNames) {
// Verify directory index.
if (FileName.DirIdx > MaxDirIndex) {
++NumDebugLineErrors;
error() << ".debug_line["
<< format("0x%08" PRIx64,
*toSectionOffset(Die.find(DW_AT_stmt_list)))
<< "].prologue.file_names[" << FileIndex
<< "].dir_idx contains an invalid index: " << FileName.DirIdx
<< "\n";
}
// Check file paths for duplicates.
std::string FullPath;
const bool HasFullPath = LineTable->getFileNameByIndex(
FileIndex, CU->getCompilationDir(),
DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, FullPath);
assert(HasFullPath && "Invalid index?");
(void)HasFullPath;
auto It = FullPathMap.find(FullPath);
if (It == FullPathMap.end())
FullPathMap[FullPath] = FileIndex;
else if (It->second != FileIndex) {
warn() << ".debug_line["
<< format("0x%08" PRIx64,
*toSectionOffset(Die.find(DW_AT_stmt_list)))
<< "].prologue.file_names[" << FileIndex
<< "] is a duplicate of file_names[" << It->second << "]\n";
}
FileIndex++;
}
// Verify rows.
uint64_t PrevAddress = 0;
uint32_t RowIndex = 0;
for (const auto &Row : LineTable->Rows) {
// Verify row address.
if (Row.Address < PrevAddress) {
++NumDebugLineErrors;
error() << ".debug_line["
<< format("0x%08" PRIx64,
*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';
}
// Verify file index.
if (Row.File > MaxFileIndex) {
++NumDebugLineErrors;
error() << ".debug_line["
<< format("0x%08" PRIx64,
*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::verifyAppleAccelTable(const DWARFSection *AccelSection,
DataExtractor *StrData,
const char *SectionName) {
unsigned NumErrors = 0;
DWARFDataExtractor AccelSectionData(DCtx.getDWARFObj(), *AccelSection,
DCtx.isLittleEndian(), 0);
AppleAcceleratorTable AccelTable(AccelSectionData, *StrData);
OS << "Verifying " << SectionName << "...\n";
// Verify that the fixed part of the header is not too short.
if (!AccelSectionData.isValidOffset(AccelTable.getSizeHdr())) {
error() << "Section is too small to fit a section header.\n";
return 1;
}
// Verify that the section is not too short.
if (Error E = AccelTable.extract()) {
error() << toString(std::move(E)) << '\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) {
error() << format("Bucket[%d] has invalid hash index: %u.\n", BucketIdx,
HashIdx);
++NumErrors;
}
}
uint32_t NumAtoms = AccelTable.getAtomsDesc().size();
if (NumAtoms == 0) {
error() << "No atoms: failed to read HashData.\n";
return 1;
}
if (!AccelTable.validateForms()) {
error() << "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))) {
error() << format("Hash[%d] has invalid HashData offset: 0x%08x.\n",
HashIdx, HashDataOffset);
++NumErrors;
}
uint32_t StrpOffset;
uint32_t StringOffset;
uint32_t StringCount = 0;
unsigned Offset;
unsigned Tag;
while ((StrpOffset = AccelSectionData.getU32(&HashDataOffset)) != 0) {
const uint32_t NumHashDataObjects =
AccelSectionData.getU32(&HashDataOffset);
for (uint32_t HashDataIdx = 0; HashDataIdx < NumHashDataObjects;
++HashDataIdx) {
std::tie(Offset, Tag) = AccelTable.readAtoms(HashDataOffset);
auto Die = DCtx.getDIEForOffset(Offset);
if (!Die) {
const uint32_t BucketIdx =
NumBuckets ? (Hash % NumBuckets) : UINT32_MAX;
StringOffset = StrpOffset;
const char *Name = StrData->getCStr(&StringOffset);
if (!Name)
Name = "<NULL>";
error() << format(
"%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, Offset, Name);
++NumErrors;
continue;
}
if ((Tag != dwarf::DW_TAG_null) && (Die.getTag() != Tag)) {
error() << "Tag " << dwarf::TagString(Tag)
<< " in accelerator table does not match Tag "
<< dwarf::TagString(Die.getTag()) << " of DIE[" << HashDataIdx
<< "].\n";
++NumErrors;
}
}
++StringCount;
}
}
return NumErrors;
}
unsigned
DWARFVerifier::verifyDebugNamesCULists(const DWARFDebugNames &AccelTable) {
// A map from CU offset to the (first) Name Index offset which claims to index
// this CU.
DenseMap<uint32_t, uint32_t> CUMap;
const uint32_t NotIndexed = std::numeric_limits<uint32_t>::max();
CUMap.reserve(DCtx.getNumCompileUnits());
for (const auto &CU : DCtx.compile_units())
CUMap[CU->getOffset()] = NotIndexed;
unsigned NumErrors = 0;
for (const DWARFDebugNames::NameIndex &NI : AccelTable) {
if (NI.getCUCount() == 0) {
error() << formatv("Name Index @ {0:x} does not index any CU\n",
NI.getUnitOffset());
++NumErrors;
continue;
}
for (uint32_t CU = 0, End = NI.getCUCount(); CU < End; ++CU) {
uint32_t Offset = NI.getCUOffset(CU);
auto Iter = CUMap.find(Offset);
if (Iter == CUMap.end()) {
error() << formatv(
"Name Index @ {0:x} references a non-existing CU @ {1:x}\n",
NI.getUnitOffset(), Offset);
++NumErrors;
continue;
}
if (Iter->second != NotIndexed) {
error() << formatv("Name Index @ {0:x} references a CU @ {1:x}, but "
"this CU is already indexed by Name Index @ {2:x}\n",
NI.getUnitOffset(), Offset, Iter->second);
continue;
}
Iter->second = NI.getUnitOffset();
}
}
for (const auto &KV : CUMap) {
if (KV.second == NotIndexed)
warn() << formatv("CU @ {0:x} not covered by any Name Index\n", KV.first);
}
return NumErrors;
}
unsigned
DWARFVerifier::verifyNameIndexBuckets(const DWARFDebugNames::NameIndex &NI,
const DataExtractor &StrData) {
struct BucketInfo {
uint32_t Bucket;
uint32_t Index;
constexpr BucketInfo(uint32_t Bucket, uint32_t Index)
: Bucket(Bucket), Index(Index) {}
bool operator<(const BucketInfo &RHS) const { return Index < RHS.Index; };
};
uint32_t NumErrors = 0;
if (NI.getBucketCount() == 0) {
warn() << formatv("Name Index @ {0:x} does not contain a hash table.\n",
NI.getUnitOffset());
return NumErrors;
}
// Build up a list of (Bucket, Index) pairs. We use this later to verify that
// each Name is reachable from the appropriate bucket.
std::vector<BucketInfo> BucketStarts;
BucketStarts.reserve(NI.getBucketCount() + 1);
for (uint32_t Bucket = 0, End = NI.getBucketCount(); Bucket < End; ++Bucket) {
uint32_t Index = NI.getBucketArrayEntry(Bucket);
if (Index > NI.getNameCount()) {
error() << formatv("Bucket {0} of Name Index @ {1:x} contains invalid "
"value {2}. Valid range is [0, {3}].\n",
Bucket, NI.getUnitOffset(), Index, NI.getNameCount());
++NumErrors;
continue;
}
if (Index > 0)
BucketStarts.emplace_back(Bucket, Index);
}
// If there were any buckets with invalid values, skip further checks as they
// will likely produce many errors which will only confuse the actual root
// problem.
if (NumErrors > 0)
return NumErrors;
// Sort the list in the order of increasing "Index" entries.
array_pod_sort(BucketStarts.begin(), BucketStarts.end());
// Insert a sentinel entry at the end, so we can check that the end of the
// table is covered in the loop below.
BucketStarts.emplace_back(NI.getBucketCount(), NI.getNameCount() + 1);
// Loop invariant: NextUncovered is the (1-based) index of the first Name
// which is not reachable by any of the buckets we processed so far (and
// hasn't been reported as uncovered).
uint32_t NextUncovered = 1;
for (const BucketInfo &B : BucketStarts) {
// Under normal circumstances B.Index be equal to NextUncovered, but it can
// be less if a bucket points to names which are already known to be in some
// bucket we processed earlier. In that case, we won't trigger this error,
// but report the mismatched hash value error instead. (We know the hash
// will not match because we have already verified that the name's hash
// puts it into the previous bucket.)
if (B.Index > NextUncovered) {
error() << formatv("Name Index @ {0:x}: Name table entries [{1}, {2}] "
"are not covered by the hash table.\n",
NI.getUnitOffset(), NextUncovered, B.Index - 1);
++NumErrors;
}
uint32_t Idx = B.Index;
// The rest of the checks apply only to non-sentinel entries.
if (B.Bucket == NI.getBucketCount())
break;
// This triggers if a non-empty bucket points to a name with a mismatched
// hash. Clients are likely to interpret this as an empty bucket, because a
// mismatched hash signals the end of a bucket, but if this is indeed an
// empty bucket, the producer should have signalled this by marking the
// bucket as empty.
uint32_t FirstHash = NI.getHashArrayEntry(Idx);
if (FirstHash % NI.getBucketCount() != B.Bucket) {
error() << formatv(
"Name Index @ {0:x}: Bucket {1} is not empty but points to a "
"mismatched hash value {2:x} (belonging to bucket {3}).\n",
NI.getUnitOffset(), B.Bucket, FirstHash,
FirstHash % NI.getBucketCount());
++NumErrors;
}
// This find the end of this bucket and also verifies that all the hashes in
// this bucket are correct by comparing the stored hashes to the ones we
// compute ourselves.
while (Idx <= NI.getNameCount()) {
uint32_t Hash = NI.getHashArrayEntry(Idx);
if (Hash % NI.getBucketCount() != B.Bucket)
break;
auto NTE = NI.getNameTableEntry(Idx);
const char *Str = StrData.getCStr(&NTE.StringOffset);
if (caseFoldingDjbHash(Str) != Hash) {
error() << formatv("Name Index @ {0:x}: String ({1}) at index {2} "
"hashes to {3:x}, but "
"the Name Index hash is {4:x}\n",
NI.getUnitOffset(), Str, Idx,
caseFoldingDjbHash(Str), Hash);
++NumErrors;
}
++Idx;
}
NextUncovered = std::max(NextUncovered, Idx);
}
return NumErrors;
}
unsigned DWARFVerifier::verifyNameIndexAttribute(
const DWARFDebugNames::NameIndex &NI, const DWARFDebugNames::Abbrev &Abbr,
DWARFDebugNames::AttributeEncoding AttrEnc) {
StringRef FormName = dwarf::FormEncodingString(AttrEnc.Form);
if (FormName.empty()) {
error() << formatv("NameIndex @ {0:x}: Abbreviation {1:x}: {2} uses an "
"unknown form: {3}.\n",
NI.getUnitOffset(), Abbr.Code, AttrEnc.Index,
AttrEnc.Form);
return 1;
}
if (AttrEnc.Index == DW_IDX_type_hash) {
if (AttrEnc.Form != dwarf::DW_FORM_data8) {
error() << formatv(
"NameIndex @ {0:x}: Abbreviation {1:x}: DW_IDX_type_hash "
"uses an unexpected form {2} (should be {3}).\n",
NI.getUnitOffset(), Abbr.Code, AttrEnc.Form, dwarf::DW_FORM_data8);
return 1;
}
}
// A list of known index attributes and their expected form classes.
// DW_IDX_type_hash is handled specially in the check above, as it has a
// specific form (not just a form class) we should expect.
struct FormClassTable {
dwarf::Index Index;
DWARFFormValue::FormClass Class;
StringLiteral ClassName;
};
static constexpr FormClassTable Table[] = {
{dwarf::DW_IDX_compile_unit, DWARFFormValue::FC_Constant, {"constant"}},
{dwarf::DW_IDX_type_unit, DWARFFormValue::FC_Constant, {"constant"}},
{dwarf::DW_IDX_die_offset, DWARFFormValue::FC_Reference, {"reference"}},
{dwarf::DW_IDX_parent, DWARFFormValue::FC_Constant, {"constant"}},
};
ArrayRef<FormClassTable> TableRef(Table);
auto Iter = find_if(TableRef, [AttrEnc](const FormClassTable &T) {
return T.Index == AttrEnc.Index;
});
if (Iter == TableRef.end()) {
warn() << formatv("NameIndex @ {0:x}: Abbreviation {1:x} contains an "
"unknown index attribute: {2}.\n",
NI.getUnitOffset(), Abbr.Code, AttrEnc.Index);
return 0;
}
if (!DWARFFormValue(AttrEnc.Form).isFormClass(Iter->Class)) {
error() << formatv("NameIndex @ {0:x}: Abbreviation {1:x}: {2} uses an "
"unexpected form {3} (expected form class {4}).\n",
NI.getUnitOffset(), Abbr.Code, AttrEnc.Index,
AttrEnc.Form, Iter->ClassName);
return 1;
}
return 0;
}
unsigned
DWARFVerifier::verifyNameIndexAbbrevs(const DWARFDebugNames::NameIndex &NI) {
if (NI.getLocalTUCount() + NI.getForeignTUCount() > 0) {
warn() << formatv("Name Index @ {0:x}: Verifying indexes of type units is "
"not currently supported.\n",
NI.getUnitOffset());
return 0;
}
unsigned NumErrors = 0;
for (const auto &Abbrev : NI.getAbbrevs()) {
StringRef TagName = dwarf::TagString(Abbrev.Tag);
if (TagName.empty()) {
warn() << formatv("NameIndex @ {0:x}: Abbreviation {1:x} references an "
"unknown tag: {2}.\n",
NI.getUnitOffset(), Abbrev.Code, Abbrev.Tag);
}
SmallSet<unsigned, 5> Attributes;
for (const auto &AttrEnc : Abbrev.Attributes) {
if (!Attributes.insert(AttrEnc.Index).second) {
error() << formatv("NameIndex @ {0:x}: Abbreviation {1:x} contains "
"multiple {2} attributes.\n",
NI.getUnitOffset(), Abbrev.Code, AttrEnc.Index);
++NumErrors;
continue;
}
NumErrors += verifyNameIndexAttribute(NI, Abbrev, AttrEnc);
}
if (NI.getCUCount() > 1 && !Attributes.count(dwarf::DW_IDX_compile_unit)) {
error() << formatv("NameIndex @ {0:x}: Indexing multiple compile units "
"and abbreviation {1:x} has no {2} attribute.\n",
NI.getUnitOffset(), Abbrev.Code,
dwarf::DW_IDX_compile_unit);
++NumErrors;
}
if (!Attributes.count(dwarf::DW_IDX_die_offset)) {
error() << formatv(
"NameIndex @ {0:x}: Abbreviation {1:x} has no {2} attribute.\n",
NI.getUnitOffset(), Abbrev.Code, dwarf::DW_IDX_die_offset);
++NumErrors;
}
}
return NumErrors;
}
static SmallVector<StringRef, 2> getNames(const DWARFDie &DIE) {
SmallVector<StringRef, 2> Result;
if (const char *Str = DIE.getName(DINameKind::ShortName))
Result.emplace_back(Str);
else if (DIE.getTag() == dwarf::DW_TAG_namespace)
Result.emplace_back("(anonymous namespace)");
if (const char *Str = DIE.getName(DINameKind::LinkageName)) {
if (Result.empty() || Result[0] != Str)
Result.emplace_back(Str);
}
return Result;
}
unsigned
DWARFVerifier::verifyNameIndexEntries(const DWARFDebugNames::NameIndex &NI,
uint32_t Name,
const DataExtractor &StrData) {
// Verifying type unit indexes not supported.
if (NI.getLocalTUCount() + NI.getForeignTUCount() > 0)
return 0;
DWARFDebugNames::NameTableEntry NTE = NI.getNameTableEntry(Name);
const char *CStr = StrData.getCStr(&NTE.StringOffset);
if (!CStr) {
error() << formatv(
"Name Index @ {0:x}: Unable to get string associated with name {1}.\n",
NI.getUnitOffset(), Name);
return 1;
}
StringRef Str(CStr);
unsigned NumErrors = 0;
unsigned NumEntries = 0;
uint32_t EntryID = NTE.EntryOffset;
Expected<DWARFDebugNames::Entry> EntryOr = NI.getEntry(&NTE.EntryOffset);
for (; EntryOr; ++NumEntries, EntryID = NTE.EntryOffset,
EntryOr = NI.getEntry(&NTE.EntryOffset)) {
uint32_t CUIndex = *EntryOr->getCUIndex();
if (CUIndex > NI.getCUCount()) {
error() << formatv("Name Index @ {0:x}: Entry @ {1:x} contains an "
"invalid CU index ({2}).\n",
NI.getUnitOffset(), EntryID, CUIndex);
++NumErrors;
continue;
}
uint32_t CUOffset = NI.getCUOffset(CUIndex);
uint64_t DIEOffset = *EntryOr->getDIESectionOffset();
DWARFDie DIE = DCtx.getDIEForOffset(DIEOffset);
if (!DIE) {
error() << formatv("Name Index @ {0:x}: Entry @ {1:x} references a "
"non-existing DIE @ {2:x}.\n",
NI.getUnitOffset(), EntryID, DIEOffset);
++NumErrors;
continue;
}
if (DIE.getDwarfUnit()->getOffset() != CUOffset) {
error() << formatv("Name Index @ {0:x}: Entry @ {1:x}: mismatched CU of "
"DIE @ {2:x}: index - {3:x}; debug_info - {4:x}.\n",
NI.getUnitOffset(), EntryID, DIEOffset, CUOffset,
DIE.getDwarfUnit()->getOffset());
++NumErrors;
}
if (DIE.getTag() != EntryOr->tag()) {
error() << formatv("Name Index @ {0:x}: Entry @ {1:x}: mismatched Tag of "
"DIE @ {2:x}: index - {3}; debug_info - {4}.\n",
NI.getUnitOffset(), EntryID, DIEOffset, EntryOr->tag(),
DIE.getTag());
++NumErrors;
}
auto EntryNames = getNames(DIE);
if (!is_contained(EntryNames, Str)) {
error() << formatv("Name Index @ {0:x}: Entry @ {1:x}: mismatched Name "
"of DIE @ {2:x}: index - {3}; debug_info - {4}.\n",
NI.getUnitOffset(), EntryID, DIEOffset, Str,
make_range(EntryNames.begin(), EntryNames.end()));
}
}
handleAllErrors(EntryOr.takeError(),
[&](const DWARFDebugNames::SentinelError &) {
if (NumEntries > 0)
return;
error() << formatv("Name Index @ {0:x}: Name {1} ({2}) is "
"not associated with any entries.\n",
NI.getUnitOffset(), Name, Str);
++NumErrors;
},
[&](const ErrorInfoBase &Info) {
error() << formatv(
"Name Index @ {0:x}: Name {1} ({2}): {3}\n",
NI.getUnitOffset(), Name, Str, Info.message());
++NumErrors;
});
return NumErrors;
}
unsigned DWARFVerifier::verifyDebugNames(const DWARFSection &AccelSection,
const DataExtractor &StrData) {
unsigned NumErrors = 0;
DWARFDataExtractor AccelSectionData(DCtx.getDWARFObj(), AccelSection,
DCtx.isLittleEndian(), 0);
DWARFDebugNames AccelTable(AccelSectionData, StrData);
OS << "Verifying .debug_names...\n";
// This verifies that we can read individual name indices and their
// abbreviation tables.
if (Error E = AccelTable.extract()) {
error() << toString(std::move(E)) << '\n';
return 1;
}
NumErrors += verifyDebugNamesCULists(AccelTable);
for (const auto &NI : AccelTable)
NumErrors += verifyNameIndexBuckets(NI, StrData);
for (const auto &NI : AccelTable)
NumErrors += verifyNameIndexAbbrevs(NI);
// Don't attempt Entry validation if any of the previous checks found errors
if (NumErrors > 0)
return NumErrors;
for (const auto &NI : AccelTable)
for (uint64_t Name = 1; Name <= NI.getNameCount(); ++Name)
NumErrors += verifyNameIndexEntries(NI, Name, StrData);
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 +=
verifyAppleAccelTable(&D.getAppleNamesSection(), &StrData, ".apple_names");
if (!D.getAppleTypesSection().Data.empty())
NumErrors +=
verifyAppleAccelTable(&D.getAppleTypesSection(), &StrData, ".apple_types");
if (!D.getAppleNamespacesSection().Data.empty())
NumErrors += verifyAppleAccelTable(&D.getAppleNamespacesSection(), &StrData,
".apple_namespaces");
if (!D.getAppleObjCSection().Data.empty())
NumErrors +=
verifyAppleAccelTable(&D.getAppleObjCSection(), &StrData, ".apple_objc");
if (!D.getDebugNamesSection().Data.empty())
NumErrors += verifyDebugNames(D.getDebugNamesSection(), StrData);
return NumErrors == 0;
}
raw_ostream &DWARFVerifier::error() const {
return WithColor(OS, HighlightColor::Error).get() << "error: ";
}
raw_ostream &DWARFVerifier::warn() const {
return WithColor(OS, HighlightColor::Warning).get() << "warning: ";
}
raw_ostream &DWARFVerifier::note() const {
return WithColor(OS, HighlightColor::Note).get() << "note: ";
}
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