[llvm] r237733 - [DWARF parser] Make DWARF parser more robust against missing compile/type units.
Alexey Samsonov
vonosmas at gmail.com
Tue May 26 12:42:14 PDT 2015
At this stage that would require producing a broken DWARF file, possibly by
manually flipping bits in the output of clang/gcc. Do we really want this
in the tree?
On Tue, May 26, 2015 at 7:06 AM, Rafael Espíndola <
rafael.espindola at gmail.com> wrote:
> testcase?
>
> On 19 May 2015 at 17:54, Alexey Samsonov <vonosmas at gmail.com> wrote:
> > Author: samsonov
> > Date: Tue May 19 16:54:32 2015
> > New Revision: 237733
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=237733&view=rev
> > Log:
> > [DWARF parser] Make DWARF parser more robust against missing
> compile/type units.
> >
> > DWARF standard claims that each compilation/type unit header in
> > .debug_info/.debug_types section must be followed by corresponding
> > compile/type unit DIE, possibly with its children. Two situations
> > are possible:
> >
> > * compile/type unit DIE is missing because DWARF producer failed to
> > emit it.
> > * DWARF parser failed to parse unit DIE correctly, for instance if it
> > contains some unsupported attributes (see r237721, for instance).
> >
> > In either of these cases, the library, and the tools that use it
> > (llvm-dwarfdump, llvm-symbolizer) should not crash. Insert appropriate
> > checks to protect against this.
> >
> > Modified:
> > llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnit.h
> > llvm/trunk/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp
> > llvm/trunk/lib/DebugInfo/DWARF/DWARFContext.cpp
> > llvm/trunk/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
> > llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp
> > llvm/trunk/tools/dsymutil/DwarfLinker.cpp
> >
> > Modified: llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnit.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnit.h?rev=237733&r1=237732&r2=237733&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnit.h (original)
> > +++ llvm/trunk/include/llvm/DebugInfo/DWARF/DWARFUnit.h Tue May 19
> 16:54:32 2015
> > @@ -195,9 +195,8 @@ public:
> > BaseAddr = base_addr;
> > }
> >
> > - const DWARFDebugInfoEntryMinimal *
> > - getCompileUnitDIE(bool extract_cu_die_only = true) {
> > - extractDIEsIfNeeded(extract_cu_die_only);
> > + const DWARFDebugInfoEntryMinimal *getUnitDIE(bool ExtractUnitDIEOnly
> = true) {
> > + extractDIEsIfNeeded(ExtractUnitDIEOnly);
> > return DieArray.empty() ? nullptr : &DieArray[0];
> > }
> >
> > @@ -226,8 +225,7 @@ public:
> > /// It is illegal to call this method with a DIE that hasn't be
> > /// created by this unit. In other word, it's illegal to call this
> > /// method on a DIE that isn't accessible by following
> > - /// children/sibling links starting from this unit's
> > - /// getCompileUnitDIE().
> > + /// children/sibling links starting from this unit's getUnitDIE().
> > uint32_t getDIEIndex(const DWARFDebugInfoEntryMinimal *DIE) {
> > assert(!DieArray.empty() && DIE >= &DieArray[0] &&
> > DIE < &DieArray[0] + DieArray.size());
> >
> > Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp?rev=237733&r1=237732&r2=237733&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp (original)
> > +++ llvm/trunk/lib/DebugInfo/DWARF/DWARFCompileUnit.cpp Tue May 19
> 16:54:32 2015
> > @@ -22,9 +22,10 @@ void DWARFCompileUnit::dump(raw_ostream
> > << " (next unit at " << format("0x%08x", getNextUnitOffset())
> > << ")\n";
> >
> > - const DWARFDebugInfoEntryMinimal *CU = getCompileUnitDIE(false);
> > - assert(CU && "Null Compile Unit?");
> > - CU->dump(OS, this, -1U);
> > + if (const DWARFDebugInfoEntryMinimal *CU = getUnitDIE(false))
> > + CU->dump(OS, this, -1U);
> > + else
> > + OS << "<compile unit can't be parsed!>\n\n";
> > }
> >
> > // VTable anchor.
> >
> > Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFContext.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFContext.cpp?rev=237733&r1=237732&r2=237733&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/DebugInfo/DWARF/DWARFContext.cpp (original)
> > +++ llvm/trunk/lib/DebugInfo/DWARF/DWARFContext.cpp Tue May 19 16:54:32
> 2015
> > @@ -140,9 +140,11 @@ void DWARFContext::dump(raw_ostream &OS,
> > OS << "\n.debug_line contents:\n";
> > for (const auto &CU : compile_units()) {
> > savedAddressByteSize = CU->getAddressByteSize();
> > - unsigned stmtOffset =
> > - CU->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
> > - CU.get(), DW_AT_stmt_list, -1U);
> > + const auto *CUDIE = CU->getUnitDIE();
> > + if (CUDIE == nullptr)
> > + continue;
> > + unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
> > + CU.get(), DW_AT_stmt_list, -1U);
> > if (stmtOffset != -1U) {
> > DataExtractor lineData(getLineSection().Data, isLittleEndian(),
> > savedAddressByteSize);
> > @@ -321,13 +323,14 @@ const DWARFDebugFrame *DWARFContext::get
> > }
> >
> > const DWARFLineTable *
> > -DWARFContext::getLineTableForUnit(DWARFUnit *cu) {
> > +DWARFContext::getLineTableForUnit(DWARFUnit *U) {
> > if (!Line)
> > Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
> > -
> > + const auto *UnitDIE = U->getUnitDIE();
> > + if (UnitDIE == nullptr)
> > + return nullptr;
> > unsigned stmtOffset =
> > - cu->getCompileUnitDIE()->getAttributeValueAsSectionOffset(
> > - cu, DW_AT_stmt_list, -1U);
> > + UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list,
> -1U);
> > if (stmtOffset == -1U)
> > return nullptr; // No line table for this compile unit.
> >
> > @@ -337,7 +340,7 @@ DWARFContext::getLineTableForUnit(DWARFU
> >
> > // We have to parse it first.
> > DataExtractor lineData(getLineSection().Data, isLittleEndian(),
> > - cu->getAddressByteSize());
> > + U->getAddressByteSize());
> > return Line->getOrParseLineTable(lineData, stmtOffset);
> > }
> >
> >
> > Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp?rev=237733&r1=237732&r2=237733&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp (original)
> > +++ llvm/trunk/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp Tue May 19 16:54:32
> 2015
> > @@ -33,7 +33,8 @@ void DWARFTypeUnit::dump(raw_ostream &OS
> > << " (next unit at " << format("0x%08x", getNextUnitOffset())
> > << ")\n";
> >
> > - const DWARFDebugInfoEntryMinimal *CU = getCompileUnitDIE(false);
> > - assert(CU && "Null Compile Unit?");
> > - CU->dump(OS, this, -1U);
> > + if (const DWARFDebugInfoEntryMinimal *TU = getUnitDIE(false))
> > + TU->dump(OS, this, -1U);
> > + else
> > + OS << "<type unit can't be parsed!>\n\n";
> > }
> >
> > Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp?rev=237733&r1=237732&r2=237733&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp (original)
> > +++ llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp Tue May 19 16:54:32 2015
> > @@ -310,8 +310,11 @@ void DWARFUnit::clearDIEs(bool KeepCUDie
> > }
> >
> > void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector
> &CURanges) {
> > - // First, check if CU DIE describes address ranges for the unit.
> > - const auto &CUDIERanges = getCompileUnitDIE()->getAddressRanges(this);
> > + const auto *U = getUnitDIE();
> > + if (U == nullptr)
> > + return;
> > + // First, check if unit DIE describes address ranges for the whole
> unit.
> > + const auto &CUDIERanges = U->getAddressRanges(this);
> > if (!CUDIERanges.empty()) {
> > CURanges.insert(CURanges.end(), CUDIERanges.begin(),
> CUDIERanges.end());
> > return;
> >
> > Modified: llvm/trunk/tools/dsymutil/DwarfLinker.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/dsymutil/DwarfLinker.cpp?rev=237733&r1=237732&r2=237733&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/tools/dsymutil/DwarfLinker.cpp (original)
> > +++ llvm/trunk/tools/dsymutil/DwarfLinker.cpp Tue May 19 16:54:32 2015
> > @@ -729,7 +729,7 @@ void DwarfStreamer::emitLocationsForUnit
> > const DWARFSection &InputSec = Dwarf.getLocSection();
> > DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(),
> AddressSize);
> > DWARFUnit &OrigUnit = Unit.getOrigUnit();
> > - const auto *OrigUnitDie = OrigUnit.getCompileUnitDIE(false);
> > + const auto *OrigUnitDie = OrigUnit.getUnitDIE(false);
> > int64_t UnitPcOffset = 0;
> > uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress(
> > &OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
> > @@ -2203,7 +2203,7 @@ void DwarfLinker::patchRangesForUnit(con
> > OrigDwarf.isLittleEndian(), AddressSize);
> > auto InvalidRange = FunctionRanges.end(), CurrRange = InvalidRange;
> > DWARFUnit &OrigUnit = Unit.getOrigUnit();
> > - const auto *OrigUnitDie = OrigUnit.getCompileUnitDIE(false);
> > + const auto *OrigUnitDie = OrigUnit.getUnitDIE(false);
> > uint64_t OrigLowPc = OrigUnitDie->getAttributeValueAsAddress(
> > &OrigUnit, dwarf::DW_AT_low_pc, -1ULL);
> > // Ranges addresses are based on the unit's low_pc. Compute the
> > @@ -2287,7 +2287,7 @@ static void insertLineSequence(std::vect
> > void DwarfLinker::patchLineTableForUnit(CompileUnit &Unit,
> > DWARFContext &OrigDwarf) {
> > const DWARFDebugInfoEntryMinimal *CUDie =
> > - Unit.getOrigUnit().getCompileUnitDIE();
> > + Unit.getOrigUnit().getUnitDIE();
> > uint64_t StmtList = CUDie->getAttributeValueAsSectionOffset(
> > &Unit.getOrigUnit(), dwarf::DW_AT_stmt_list, -1ULL);
> > if (StmtList == -1ULL)
> > @@ -2461,7 +2461,7 @@ bool DwarfLinker::link(const DebugMap &M
> > // In a first phase, just read in the debug info and store the DIE
> > // parent links that we will use during the next phase.
> > for (const auto &CU : DwarfContext.compile_units()) {
> > - auto *CUDie = CU->getCompileUnitDIE(false);
> > + auto *CUDie = CU->getUnitDIE(false);
> > if (Options.Verbose) {
> > outs() << "Input compilation unit:";
> > CUDie->dump(outs(), CU.get(), 0);
> > @@ -2476,7 +2476,7 @@ bool DwarfLinker::link(const DebugMap &M
> > // references require the ParentIdx to be setup for every CU in
> > // the object file before calling this.
> > for (auto &CurrentUnit : Units)
> > - lookForDIEsToKeep(*CurrentUnit.getOrigUnit().getCompileUnitDIE(),
> *Obj,
> > + lookForDIEsToKeep(*CurrentUnit.getOrigUnit().getUnitDIE(), *Obj,
> > CurrentUnit, 0);
> >
> > // The calls to applyValidRelocs inside cloneDIE will walk the
> > @@ -2489,7 +2489,7 @@ bool DwarfLinker::link(const DebugMap &M
> > // to clone/emit.
> > if (!ValidRelocs.empty())
> > for (auto &CurrentUnit : Units) {
> > - const auto *InputDIE =
> CurrentUnit.getOrigUnit().getCompileUnitDIE();
> > + const auto *InputDIE = CurrentUnit.getOrigUnit().getUnitDIE();
> > CurrentUnit.setStartOffset(OutputDebugInfoSize);
> > DIE *OutputDIE = cloneDIE(*InputDIE, CurrentUnit, 0 /* PCOffset
> */,
> > 11 /* Unit Header size */);
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
--
Alexey Samsonov
vonosmas at gmail.com
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