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DWARFVerifier.cpp
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//===- DWARFVerifier.cpp --------------------------------------------------===//
//
// 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/DWARFVerifier.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/BinaryFormat/Dwarf.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/DebugInfo/DWARF/DWARFUnitIndex.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;
Optional<DWARFAddressRange>
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) {
DWARFAddressRange Range(*Pos);
if (Pos->merge(R))
return Range;
}
if (Pos != Begin) {
auto Iter = Pos - 1;
DWARFAddressRange Range(*Iter);
if (Iter->merge(R))
return Range;
}
Ranges.insert(Pos, R);
return None;
}
DWARFVerifier::DieRangeInfo::die_range_info_iterator
DWARFVerifier::DieRangeInfo::insert(const DieRangeInfo &RI) {
if (RI.Ranges.empty())
return Children.end();
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 {
auto I1 = Ranges.begin(), E1 = Ranges.end();
auto I2 = RHS.Ranges.begin(), E2 = RHS.Ranges.end();
if (I2 == E2)
return true;
DWARFAddressRange R = *I2;
while (I1 != E1) {
bool Covered = I1->LowPC <= R.LowPC;
if (R.LowPC == R.HighPC || (Covered && R.HighPC <= I1->HighPC)) {
if (++I2 == E2)
return true;
R = *I2;
continue;
}
if (!Covered)
return false;
if (R.LowPC < I1->HighPC)
R.LowPC = I1->HighPC;
++I1;
}
return false;
}
bool DWARFVerifier::DieRangeInfo::intersects(const DieRangeInfo &RHS) const {
auto I1 = Ranges.begin(), E1 = Ranges.end();
auto I2 = RHS.Ranges.begin(), E2 = RHS.Ranges.end();
while (I1 != E1 && I2 != E2) {
if (I1->intersects(*I2))
return true;
if (I1->LowPC < I2->LowPC)
++I1;
else
++I2;
}
return false;
}
bool DWARFVerifier::verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
uint64_t *Offset, unsigned UnitIndex,
uint8_t &UnitType, bool &isUnitDWARF64) {
uint64_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;
uint64_t OffsetStart = *Offset;
DwarfFormat Format;
std::tie(Length, Format) = DebugInfoData.getInitialLength(Offset);
isUnitDWARF64 = Format == DWARF64;
Version = DebugInfoData.getU16(Offset);
if (Version >= 5) {
UnitType = DebugInfoData.getU8(Offset);
AddrSize = DebugInfoData.getU8(Offset);
AbbrOffset = isUnitDWARF64 ? DebugInfoData.getU64(Offset) : DebugInfoData.getU32(Offset);
ValidType = dwarf::isUnitType(UnitType);
} else {
UnitType = 0;
AbbrOffset = isUnitDWARF64 ? DebugInfoData.getU64(Offset) : 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 = DWARFContext::isAddressSizeSupported(AddrSize);
if (!ValidLength || !ValidVersion || !ValidAddrSize || !ValidAbbrevOffset ||
!ValidType) {
Success = false;
error() << format("Units[%d] - start offset: 0x%08" PRIx64 " \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 + (isUnitDWARF64 ? 12 : 4);
return Success;
}
bool DWARFVerifier::verifyName(const DWARFDie &Die) {
// FIXME Add some kind of record of which DIE names have already failed and
// don't bother checking a DIE that uses an already failed DIE.
std::string ReconstructedName;
raw_string_ostream OS(ReconstructedName);
std::string OriginalFullName;
Die.getFullName(OS, &OriginalFullName);
OS.flush();
if (OriginalFullName.empty() || OriginalFullName == ReconstructedName)
return false;
error() << "Simplified template DW_AT_name could not be reconstituted:\n"
<< formatv(" original: {0}\n"
" reconstituted: {1}\n",
OriginalFullName, ReconstructedName);
dump(Die) << '\n';
dump(Die.getDwarfUnit()->getUnitDIE()) << '\n';
return true;
}
unsigned DWARFVerifier::verifyUnitContents(DWARFUnit &Unit,
ReferenceMap &UnitLocalReferences,
ReferenceMap &CrossUnitReferences) {
unsigned 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, UnitLocalReferences,
CrossUnitReferences);
}
NumUnitErrors += verifyName(Die);
if (Die.hasChildren()) {
if (Die.getFirstChild().isValid() &&
Die.getFirstChild().getTag() == DW_TAG_null) {
warn() << dwarf::TagString(Die.getTag())
<< " has DW_CHILDREN_yes but DIE has no children: ";
Die.dump(OS);
}
}
NumUnitErrors += verifyDebugInfoCallSite(Die);
}
DWARFDie Die = Unit.getUnitDIE(/* ExtractUnitDIEOnly = */ false);
if (!Die) {
error() << "Compilation unit without DIE.\n";
NumUnitErrors++;
return NumUnitErrors;
}
if (!dwarf::isUnitType(Die.getTag())) {
error() << "Compilation unit root DIE is not a unit DIE: "
<< dwarf::TagString(Die.getTag()) << ".\n";
NumUnitErrors++;
}
uint8_t UnitType = Unit.getUnitType();
if (!DWARFUnit::isMatchingUnitTypeAndTag(UnitType, Die.getTag())) {
error() << "Compilation unit type (" << dwarf::UnitTypeString(UnitType)
<< ") and root DIE (" << dwarf::TagString(Die.getTag())
<< ") do not match.\n";
NumUnitErrors++;
}
// According to DWARF Debugging Information Format Version 5,
// 3.1.2 Skeleton Compilation Unit Entries:
// "A skeleton compilation unit has no children."
if (Die.getTag() == dwarf::DW_TAG_skeleton_unit && Die.hasChildren()) {
error() << "Skeleton compilation unit has children.\n";
NumUnitErrors++;
}
DieRangeInfo RI;
NumUnitErrors += verifyDieRanges(Die, RI);
return NumUnitErrors;
}
unsigned DWARFVerifier::verifyDebugInfoCallSite(const DWARFDie &Die) {
if (Die.getTag() != DW_TAG_call_site && Die.getTag() != DW_TAG_GNU_call_site)
return 0;
DWARFDie Curr = Die.getParent();
for (; Curr.isValid() && !Curr.isSubprogramDIE(); Curr = Die.getParent()) {
if (Curr.getTag() == DW_TAG_inlined_subroutine) {
error() << "Call site entry nested within inlined subroutine:";
Curr.dump(OS);
return 1;
}
}
if (!Curr.isValid()) {
error() << "Call site entry not nested within a valid subprogram:";
Die.dump(OS);
return 1;
}
Optional<DWARFFormValue> CallAttr =
Curr.find({DW_AT_call_all_calls, DW_AT_call_all_source_calls,
DW_AT_call_all_tail_calls, DW_AT_GNU_all_call_sites,
DW_AT_GNU_all_source_call_sites,
DW_AT_GNU_all_tail_call_sites});
if (!CallAttr) {
error() << "Subprogram with call site entry has no DW_AT_call attribute:";
Curr.dump(OS);
Die.dump(OS, /*indent*/ 1);
return 1;
}
return 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();
unsigned NumErrors = 0;
if (!DObj.getAbbrevSection().empty())
NumErrors += verifyAbbrevSection(DCtx.getDebugAbbrev());
if (!DObj.getAbbrevDWOSection().empty())
NumErrors += verifyAbbrevSection(DCtx.getDebugAbbrevDWO());
return NumErrors == 0;
}
unsigned DWARFVerifier::verifyUnits(const DWARFUnitVector &Units) {
unsigned NumDebugInfoErrors = 0;
ReferenceMap CrossUnitReferences;
unsigned Index = 1;
for (const auto &Unit : Units) {
OS << "Verifying unit: " << Index << " / " << Units.getNumUnits();
if (const char* Name = Unit->getUnitDIE(true).getShortName())
OS << ", \"" << Name << '\"';
OS << '\n';
OS.flush();
ReferenceMap UnitLocalReferences;
NumDebugInfoErrors +=
verifyUnitContents(*Unit, UnitLocalReferences, CrossUnitReferences);
NumDebugInfoErrors += verifyDebugInfoReferences(
UnitLocalReferences, [&](uint64_t Offset) { return Unit.get(); });
++Index;
}
NumDebugInfoErrors += verifyDebugInfoReferences(
CrossUnitReferences, [&](uint64_t Offset) -> DWARFUnit * {
if (DWARFUnit *U = Units.getUnitForOffset(Offset))
return U;
return nullptr;
});
return NumDebugInfoErrors;
}
unsigned DWARFVerifier::verifyUnitSection(const DWARFSection &S) {
const DWARFObject &DObj = DCtx.getDWARFObj();
DWARFDataExtractor DebugInfoData(DObj, S, DCtx.isLittleEndian(), 0);
unsigned NumDebugInfoErrors = 0;
uint64_t Offset = 0, UnitIdx = 0;
uint8_t UnitType = 0;
bool isUnitDWARF64 = false;
bool isHeaderChainValid = true;
bool hasDIE = DebugInfoData.isValidOffset(Offset);
DWARFUnitVector TypeUnitVector;
DWARFUnitVector CompileUnitVector;
/// A map that tracks all references (converted absolute references) so we
/// can verify each reference points to a valid DIE and not an offset that
/// lies between to valid DIEs.
ReferenceMap CrossUnitReferences;
while (hasDIE) {
if (!verifyUnitHeader(DebugInfoData, &Offset, UnitIdx, UnitType,
isUnitDWARF64)) {
isHeaderChainValid = false;
if (isUnitDWARF64)
break;
}
hasDIE = DebugInfoData.isValidOffset(Offset);
++UnitIdx;
}
if (UnitIdx == 0 && !hasDIE) {
warn() << "Section is empty.\n";
isHeaderChainValid = true;
}
if (!isHeaderChainValid)
++NumDebugInfoErrors;
return NumDebugInfoErrors;
}
bool DWARFVerifier::handleDebugInfo() {
const DWARFObject &DObj = DCtx.getDWARFObj();
unsigned NumErrors = 0;
OS << "Verifying .debug_info Unit Header Chain...\n";
DObj.forEachInfoSections([&](const DWARFSection &S) {
NumErrors += verifyUnitSection(S);
});
OS << "Verifying .debug_types Unit Header Chain...\n";
DObj.forEachTypesSections([&](const DWARFSection &S) {
NumErrors += verifyUnitSection(S);
});
OS << "Verifying non-dwo Units...\n";
NumErrors += verifyUnits(DCtx.getNormalUnitsVector());
OS << "Verifying dwo Units...\n";
NumErrors += verifyUnits(DCtx.getDWOUnitsVector());
return NumErrors == 0;
}
unsigned DWARFVerifier::verifyDieRanges(const DWARFDie &Die,
DieRangeInfo &ParentRI) {
unsigned NumErrors = 0;
if (!Die.isValid())
return NumErrors;
DWARFUnit *Unit = Die.getDwarfUnit();
auto RangesOrError = Die.getAddressRanges();
if (!RangesOrError) {
// FIXME: Report the error.
if (!Unit->isDWOUnit())
++NumErrors;
llvm::consumeError(RangesOrError.takeError());
return NumErrors;
}
const DWARFAddressRangesVector &Ranges = RangesOrError.get();
// Build RI for this DIE and check that ranges within this DIE do not
// overlap.
DieRangeInfo RI(Die);
// TODO support object files better
//
// Some object file formats (i.e. non-MachO) support COMDAT. ELF in
// particular does so by placing each function into a section. The DWARF data
// for the function at that point uses a section relative DW_FORM_addrp for
// the DW_AT_low_pc and a DW_FORM_data4 for the offset as the DW_AT_high_pc.
// In such a case, when the Die is the CU, the ranges will overlap, and we
// will flag valid conflicting ranges as invalid.
//
// For such targets, we should read the ranges from the CU and partition them
// by the section id. The ranges within a particular section should be
// disjoint, although the ranges across sections may overlap. We would map
// the child die to the entity that it references and the section with which
// it is associated. The child would then be checked against the range
// information for the associated section.
//
// For now, simply elide the range verification for the CU DIEs if we are
// processing an object file.
if (!IsObjectFile || IsMachOObject || Die.getTag() != DW_TAG_compile_unit) {
bool DumpDieAfterError = false;
for (const auto &Range : Ranges) {
if (!Range.valid()) {
++NumErrors;
error() << "Invalid address range " << Range << "\n";
DumpDieAfterError = true;
continue;
}
// Verify that ranges don't intersect and also build up the DieRangeInfo
// address ranges. Don't break out of the loop below early, or we will
// think this DIE doesn't have all of the address ranges it is supposed
// to have. Compile units often have DW_AT_ranges that can contain one or
// more dead stripped address ranges which tend to all be at the same
// address: 0 or -1.
if (auto PrevRange = RI.insert(Range)) {
++NumErrors;
error() << "DIE has overlapping ranges in DW_AT_ranges attribute: "
<< *PrevRange << " and " << Range << '\n';
DumpDieAfterError = true;
}
}
if (DumpDieAfterError)
dump(Die, 2) << '\n';
}
// Verify that children don't intersect.
const auto IntersectingChild = ParentRI.insert(RI);
if (IntersectingChild != ParentRI.Children.end()) {
++NumErrors;
error() << "DIEs have overlapping address ranges:";
dump(Die);
dump(IntersectingChild->Die) << '\n';
}
// Verify that ranges are contained within their parent.
bool ShouldBeContained = !RI.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:";
dump(ParentRI.Die);
dump(Die, 2) << '\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';
dump(Die) << '\n';
};
const DWARFObject &DObj = DCtx.getDWARFObj();
DWARFUnit *U = Die.getDwarfUnit();
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()) {
unsigned DwarfVersion = U->getVersion();
const DWARFSection &RangeSection = DwarfVersion < 5
? DObj.getRangesSection()
: DObj.getRnglistsSection();
if (U->isDWOUnit() && RangeSection.Data.empty())
break;
if (*SectionOffset >= RangeSection.Data.size())
ReportError(
"DW_AT_ranges offset is beyond " +
StringRef(DwarfVersion < 5 ? ".debug_ranges" : ".debug_rnglists") +
" bounds: " + llvm::formatv("{0:x8}", *SectionOffset));
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 >= U->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: {
// FIXME: It might be nice if there's a way to walk location expressions
// without trying to resolve the address ranges - it'd be a more efficient
// API (since the API is currently unnecessarily resolving addresses for
// this use case which only wants to validate the expressions themselves) &
// then the expressions could be validated even if the addresses can't be
// resolved.
// That sort of API would probably look like a callback "for each
// expression" with some way to lazily resolve the address ranges when
// needed (& then the existing API used here could be built on top of that -
// using the callback API to build the data structure and return it).
if (Expected<std::vector<DWARFLocationExpression>> Loc =
Die.getLocations(DW_AT_location)) {
for (const auto &Entry : *Loc) {
DataExtractor Data(toStringRef(Entry.Expr), DCtx.isLittleEndian(), 0);
DWARFExpression Expression(Data, U->getAddressByteSize(),
U->getFormParams().Format);
bool Error =
any_of(Expression, [](const DWARFExpression::Operation &Op) {
return Op.isError();
});
if (Error || !Expression.verify(U))
ReportError("DIE contains invalid DWARF expression:");
}
} else if (Error Err = handleErrors(
Loc.takeError(), [&](std::unique_ptr<ResolverError> E) {
return U->isDWOUnit() ? Error::success()
: Error(std::move(E));
}))
ReportError(toString(std::move(Err)));
break;
}
case DW_AT_specification:
case DW_AT_abstract_origin: {
if (auto ReferencedDie = Die.getAttributeValueAsReferencedDie(Attr)) {
auto DieTag = Die.getTag();
auto RefTag = ReferencedDie.getTag();
if (DieTag == RefTag)
break;
if (DieTag == DW_TAG_inlined_subroutine && RefTag == DW_TAG_subprogram)
break;
if (DieTag == DW_TAG_variable && RefTag == DW_TAG_member)
break;
// This might be reference to a function declaration.
if (DieTag == DW_TAG_GNU_call_site && RefTag == DW_TAG_subprogram)
break;
ReportError("DIE with tag " + TagString(DieTag) + " has " +
AttributeString(Attr) +
" that points to DIE with "
"incompatible tag " +
TagString(RefTag));
}
break;
}
case DW_AT_type: {
DWARFDie TypeDie = Die.getAttributeValueAsReferencedDie(DW_AT_type);
if (TypeDie && !isType(TypeDie.getTag())) {
ReportError("DIE has " + AttributeString(Attr) +
" with incompatible tag " + TagString(TypeDie.getTag()));
}
break;
}
case DW_AT_call_file:
case DW_AT_decl_file: {
if (auto FileIdx = AttrValue.Value.getAsUnsignedConstant()) {
if (U->isDWOUnit() && !U->isTypeUnit())
break;
const auto *LT = U->getContext().getLineTableForUnit(U);
if (LT) {
if (!LT->hasFileAtIndex(*FileIdx)) {
bool IsZeroIndexed = LT->Prologue.getVersion() >= 5;
if (Optional<uint64_t> LastFileIdx = LT->getLastValidFileIndex()) {
ReportError("DIE has " + AttributeString(Attr) +
" with an invalid file index " +
llvm::formatv("{0}", *FileIdx) +
" (valid values are [" + (IsZeroIndexed ? "0-" : "1-") +
llvm::formatv("{0}", *LastFileIdx) + "])");
} else {
ReportError("DIE has " + AttributeString(Attr) +
" with an invalid file index " +
llvm::formatv("{0}", *FileIdx) +
" (the file table in the prologue is empty)");
}
}
} else {
ReportError("DIE has " + AttributeString(Attr) +
" that references a file with index " +
llvm::formatv("{0}", *FileIdx) +
" and the compile unit has no line table");
}
} else {
ReportError("DIE has " + AttributeString(Attr) +
" with invalid encoding");
}
break;
}
default:
break;
}
return NumErrors;
}
unsigned DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
DWARFAttribute &AttrValue,
ReferenceMap &LocalReferences,
ReferenceMap &CrossUnitReferences) {
auto DieCU = Die.getDwarfUnit();
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 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" PRIx64, CUSize) << "):\n";
Die.dump(OS, 0, DumpOpts);
dump(Die) << '\n';
} else {
// Valid reference, but we will verify it points to an actual
// DIE later.
LocalReferences[*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 >= DieCU->getInfoSection().Data.size()) {
++NumErrors;
error() << "DW_FORM_ref_addr offset beyond .debug_info "
"bounds:\n";
dump(Die) << '\n';
} else {
// Valid reference, but we will verify it points to an actual
// DIE later.
CrossUnitReferences[*RefVal].insert(Die.getOffset());
}
}
break;
}
case DW_FORM_strp:
case DW_FORM_strx:
case DW_FORM_strx1:
case DW_FORM_strx2:
case DW_FORM_strx3:
case DW_FORM_strx4: {
if (Error E = AttrValue.Value.getAsCString().takeError()) {
++NumErrors;
error() << toString(std::move(E)) << ":\n";
dump(Die) << '\n';
}
break;
}
default:
break;
}
return NumErrors;
}
unsigned DWARFVerifier::verifyDebugInfoReferences(
const ReferenceMap &References,
llvm::function_ref<DWARFUnit *(uint64_t)> GetUnitForOffset) {
auto GetDIEForOffset = [&](uint64_t Offset) {
if (DWARFUnit *U = GetUnitForOffset(Offset))
return U->getDIEForOffset(Offset);
return DWARFDie();
};
unsigned NumErrors = 0;
for (const std::pair<const uint64_t, std::set<uint64_t>> &Pair :
References) {
if (GetDIEForOffset(Pair.first))
continue;
++NumErrors;
error() << "invalid DIE reference " << format("0x%08" PRIx64, Pair.first)
<< ". Offset is in between DIEs:\n";
for (auto Offset : Pair.second)
dump(GetDIEForOffset(Offset)) << '\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 uint64_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" PRIx64, LineTableOffset)
<< "] was not able to be parsed for CU:\n";
dump(Die) << '\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" PRIx64, Iter->second.getOffset()) << " and "
<< format("0x%08" PRIx64, Die.getOffset())
<< ", have the same DW_AT_stmt_list section offset:\n";
dump(Iter->second);
dump(Die) << '\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 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.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, 0);
if (RowIndex > 0)
LineTable->Rows[RowIndex - 1].dump(OS);
Row.dump(OS);
OS << '\n';
}
// Verify file index.
if (!LineTable->hasFileAtIndex(Row.File)) {
++NumDebugLineErrors;
bool isDWARF5 = LineTable->Prologue.getVersion() >= 5;
error() << ".debug_line["
<< format("0x%08" PRIx64,
*toSectionOffset(Die.find(DW_AT_stmt_list)))
<< "][" << RowIndex << "] has invalid file index " << Row.File
<< " (valid values are [" << (isDWARF5 ? "0," : "1,")
<< LineTable->Prologue.FileNames.size()
<< (isDWARF5 ? ")" : "]") << "):\n";
DWARFDebugLine::Row::dumpTableHeader(OS, 0);
Row.dump(OS);
OS << '\n';
}
if (Row.EndSequence)
PrevAddress = 0;
else
PrevAddress = Row.Address.Address;
++RowIndex;
}
}
}
DWARFVerifier::DWARFVerifier(raw_ostream &S, DWARFContext &D,
DIDumpOptions DumpOpts)
: OS(S), DCtx(D), DumpOpts(std::move(DumpOpts)), IsObjectFile(false),
IsMachOObject(false) {
if (const auto *F = DCtx.getDWARFObj().getFile()) {
IsObjectFile = F->isRelocatableObject();
IsMachOObject = F->isMachO();
}
}
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();
uint64_t BucketsOffset =
AccelTable.getSizeHdr() + AccelTable.getHeaderDataLength();
uint64_t HashesBase = BucketsOffset + NumBuckets * 4;
uint64_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) {
uint64_t HashOffset = HashesBase + 4 * HashIdx;
uint64_t DataOffset = OffsetsBase + 4 * HashIdx;
uint32_t Hash = AccelSectionData.getU32(&HashOffset);
uint64_t HashDataOffset = AccelSectionData.getU32(&DataOffset);
if (!AccelSectionData.isValidOffsetForDataOfSize(HashDataOffset,
sizeof(uint64_t))) {
error() << format("Hash[%d] has invalid HashData offset: "
"0x%08" PRIx64 ".\n",
HashIdx, HashDataOffset);
++NumErrors;
}
uint64_t StrpOffset;
uint64_t StringOffset;
uint32_t StringCount = 0;
uint64_t 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%08" PRIx64 " DIE[%d] = 0x%08" PRIx64 " "
"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.