[llvm] r258931 - [DebugInfo] Support zero-length CIE in the _eh_frame parser
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 2 11:51:29 PST 2016
Why do you need to check in a binary to test this? llvm-mc should be
sufficient, no?
Cheers,
Rafael
On 27 January 2016 at 09:05, Igor Laevsky via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: igor.laevsky
> Date: Wed Jan 27 08:05:35 2016
> New Revision: 258931
>
> URL: http://llvm.org/viewvc/llvm-project?rev=258931&view=rev
> Log:
> [DebugInfo] Support zero-length CIE in the _eh_frame parser
>
> MCJIT emits zero-length CIE at the end of the _eh_frame section. This change
> ensures that parser inside DebugInfo will not crash and correctly record such cases.
> We are now recording DW_EH_PE_omit as a default value for FDE and LSDA encodings.
> Also Offset != EndAugmentationOffset assertion check will only happen if augmentation
> string had 'z' letter in it.
>
> Differential Revision: http://reviews.llvm.org/D16588
>
>
> Added:
> llvm/trunk/test/tools/llvm-objdump/Inputs/eh_frame_zero_cie.o (with props)
> llvm/trunk/test/tools/llvm-objdump/eh_frame_zero_cie.test
> Modified:
> llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
>
> Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp?rev=258931&r1=258930&r2=258931&view=diff
> ==============================================================================
> --- llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp (original)
> +++ llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp Wed Jan 27 08:05:35 2016
> @@ -201,8 +201,8 @@ public:
> SmallString<8> Augmentation, uint8_t AddressSize,
> uint8_t SegmentDescriptorSize, uint64_t CodeAlignmentFactor,
> int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister,
> - SmallString<8> AugmentationData, Optional<uint32_t> FDEPointerEncoding,
> - Optional<uint32_t> LSDAPointerEncoding)
> + SmallString<8> AugmentationData, uint32_t FDEPointerEncoding,
> + uint32_t LSDAPointerEncoding)
> : FrameEntry(FK_CIE, Offset, Length), Version(Version),
> Augmentation(std::move(Augmentation)),
> AddressSize(AddressSize),
> @@ -219,10 +219,10 @@ public:
> StringRef getAugmentationString() const { return Augmentation; }
> uint64_t getCodeAlignmentFactor() const { return CodeAlignmentFactor; }
> int64_t getDataAlignmentFactor() const { return DataAlignmentFactor; }
> - Optional<uint32_t> getFDEPointerEncoding() const {
> + uint32_t getFDEPointerEncoding() const {
> return FDEPointerEncoding;
> }
> - Optional<uint32_t> getLSDAPointerEncoding() const {
> + uint32_t getLSDAPointerEncoding() const {
> return LSDAPointerEncoding;
> }
>
> @@ -265,8 +265,8 @@ private:
>
> // The following are used when the CIE represents an EH frame entry.
> SmallString<8> AugmentationData;
> - Optional<uint32_t> FDEPointerEncoding;
> - Optional<uint32_t> LSDAPointerEncoding;
> + uint32_t FDEPointerEncoding;
> + uint32_t LSDAPointerEncoding;
> };
>
>
> @@ -556,16 +556,16 @@ void DWARFDebugFrame::parse(DataExtracto
> uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);
>
> // Parse the augmentation data for EH CIEs
> - StringRef AugmentationData;
> - Optional<uint32_t> FDEPointerEncoding;
> - Optional<uint32_t> LSDAPointerEncoding;
> + StringRef AugmentationData("");
> + uint32_t FDEPointerEncoding = DW_EH_PE_omit;
> + uint32_t LSDAPointerEncoding = DW_EH_PE_omit;
> if (IsEH) {
> Optional<uint32_t> PersonalityEncoding;
> Optional<uint64_t> Personality;
>
> - uint64_t AugmentationLength = 0;
> - uint32_t StartAugmentationOffset = 0;
> - uint32_t EndAugmentationOffset = 0;
> + Optional<uint64_t> AugmentationLength;
> + uint32_t StartAugmentationOffset;
> + uint32_t EndAugmentationOffset;
>
> // Walk the augmentation string to get all the augmentation data.
> for (unsigned i = 0, e = AugmentationString.size(); i != e; ++i) {
> @@ -573,8 +573,6 @@ void DWARFDebugFrame::parse(DataExtracto
> default:
> ReportError("Unknown augmentation character in entry at %lx");
> case 'L':
> - if (LSDAPointerEncoding)
> - ReportError("Duplicate LSDA encoding in entry at %lx");
> LSDAPointerEncoding = Data.getU8(&Offset);
> break;
> case 'P': {
> @@ -585,8 +583,6 @@ void DWARFDebugFrame::parse(DataExtracto
> break;
> }
> case 'R':
> - if (FDEPointerEncoding)
> - ReportError("Duplicate FDE encoding in entry at %lx");
> FDEPointerEncoding = Data.getU8(&Offset);
> break;
> case 'z':
> @@ -596,20 +592,22 @@ void DWARFDebugFrame::parse(DataExtracto
> // the string contains a 'z'.
> AugmentationLength = Data.getULEB128(&Offset);
> StartAugmentationOffset = Offset;
> - EndAugmentationOffset =
> - Offset + static_cast<uint32_t>(AugmentationLength);
> + EndAugmentationOffset = Offset +
> + static_cast<uint32_t>(*AugmentationLength);
> }
> }
>
> - if (Offset != EndAugmentationOffset)
> - ReportError("Parsing augmentation data at %lx failed");
> + if (AugmentationLength.hasValue()) {
> + if (Offset != EndAugmentationOffset)
> + ReportError("Parsing augmentation data at %lx failed");
>
> - AugmentationData = Data.getData().slice(StartAugmentationOffset,
> - EndAugmentationOffset);
> + AugmentationData = Data.getData().slice(StartAugmentationOffset,
> + EndAugmentationOffset);
> + }
> }
>
> auto Cie = make_unique<CIE>(StartOffset, Length, Version,
> - StringRef(Augmentation), AddressSize,
> + AugmentationString, AddressSize,
> SegmentDescriptorSize, CodeAlignmentFactor,
> DataAlignmentFactor, ReturnAddressRegister,
> AugmentationData, FDEPointerEncoding,
> @@ -628,12 +626,11 @@ void DWARFDebugFrame::parse(DataExtracto
> if (!Cie)
> ReportError("Parsing FDE data at %lx failed due to missing CIE");
>
> - Optional<uint32_t> FDEPointerEncoding = Cie->getFDEPointerEncoding();
> - if (!FDEPointerEncoding)
> - ReportError("Parsing at %lx failed due to missing pointer encoding");
> + InitialLocation = readPointer(Data, Offset,
> + Cie->getFDEPointerEncoding());
> + AddressRange = readPointer(Data, Offset,
> + Cie->getFDEPointerEncoding());
>
> - InitialLocation = readPointer(Data, Offset, *FDEPointerEncoding);
> - AddressRange = readPointer(Data, Offset, *FDEPointerEncoding);
> StringRef AugmentationString = Cie->getAugmentationString();
> if (!AugmentationString.empty()) {
> // Parse the augmentation length and data for this FDE.
> @@ -644,8 +641,8 @@ void DWARFDebugFrame::parse(DataExtracto
>
> // Decode the LSDA if the CIE augmentation string said we should.
> uint64_t LSDA = 0;
> - if (Optional<uint32_t> Encoding = Cie->getLSDAPointerEncoding())
> - LSDA = readPointer(Data, Offset, *Encoding);
> + if (Cie->getLSDAPointerEncoding() != DW_EH_PE_omit)
> + LSDA = readPointer(Data, Offset, Cie->getLSDAPointerEncoding());
>
> if (Offset != EndAugmentationOffset)
> ReportError("Parsing augmentation data at %lx failed");
>
> Added: llvm/trunk/test/tools/llvm-objdump/Inputs/eh_frame_zero_cie.o
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objdump/Inputs/eh_frame_zero_cie.o?rev=258931&view=auto
> ==============================================================================
> Binary file - no diff available.
>
> Propchange: llvm/trunk/test/tools/llvm-objdump/Inputs/eh_frame_zero_cie.o
> ------------------------------------------------------------------------------
> svn:mime-type = application/octet-stream
>
> Added: llvm/trunk/test/tools/llvm-objdump/eh_frame_zero_cie.test
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objdump/eh_frame_zero_cie.test?rev=258931&view=auto
> ==============================================================================
> --- llvm/trunk/test/tools/llvm-objdump/eh_frame_zero_cie.test (added)
> +++ llvm/trunk/test/tools/llvm-objdump/eh_frame_zero_cie.test Wed Jan 27 08:05:35 2016
> @@ -0,0 +1,10 @@
> +# RUN: llvm-objdump -dwarf=frames %p/Inputs/eh_frame_zero_cie.o 2>/dev/null | FileCheck %s
> +
> +# CHECK: .eh_frame contents:
> +
> +# CHECK: 00000000 00000000 ffffffff CIE
> +# CHECK: Version: 0
> +# CHECK: Augmentation: ""
> +# CHECK: Code alignment factor: 0
> +# CHECK: Data alignment factor: 0
> +# CHECK: Return address column: 0
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
More information about the llvm-commits
mailing list