[llvm] r218380 - Replace a hand-written suffix compare with std::lexicographical_compare.
Alexey Samsonov
vonosmas at gmail.com
Wed Sep 24 14:04:43 PDT 2014
MSan bootstrap also fails on this:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/4564/steps/check-llvm%20msan/logs/stdio
On Wed, Sep 24, 2014 at 1:48 PM, Akira Hatanaka <ahatanak at gmail.com> wrote:
> Hi Benjamin,
>
> I reverted this commit since it was breaking a few build bots. These two
> tests were failing:
>
> Failing Tests (2):
>
> LLVM :: MC/ELF/many-sections-2.s
>
> LLVM :: MC/ELF/many-sections.s
>
> This is the stack dump when many_sections.s was assembled with llvm-mc:
>
> FAIL: LLVM :: MC/ELF/many-sections-2.s (11630 of 11631)
>
>
> Exit Code: 139
>
>
> Command Output (stderr):
>
> --
>
> 0 llvm-mc 0x000000010994685e
> llvm::sys::PrintStackTrace(__sFILE*) + 46
>
> 1 llvm-mc 0x0000000109946b6b
> PrintStackTraceSignalHandler(void*) + 27
>
> 2 llvm-mc 0x0000000109946f95 SignalHandler(int) + 565
>
> 3 libsystem_platform.dylib 0x00007fff936bb5aa _sigtramp + 26
>
> 4 libsystem_platform.dylib 0x00007fd2c7bef91e _sigtramp + 877872014
>
> 5 llvm-mc 0x00000001098e71c0 void
> std::__1::__sort<llvm::StringTableBuilder::finalize()::$_0&,
> llvm::StringRef*>(llvm::StringRef*, llvm::StringRef*,
> llvm::StringTableBuilder::finalize()::$_0&) + 768
>
> 6 llvm-mc 0x00000001098e7dad void
> std::__1::__sort<llvm::StringTableBuilder::finalize()::$_0&,
> llvm::StringRef*>(llvm::StringRef*, llvm::StringRef*,
> llvm::StringTableBuilder::finalize()::$_0&) + 3821
>
> 7 llvm-mc 0x00000001098e7dad void
> std::__1::__sort<llvm::StringTableBuilder::finalize()::$_0&,
> llvm::StringRef*>(llvm::StringRef*, llvm::StringRef*,
> llvm::StringTableBuilder::finalize()::$_0&) + 3821
>
> 8 llvm-mc 0x00000001098e7dad void
> std::__1::__sort<llvm::StringTableBuilder::finalize()::$_0&,
> llvm::StringRef*>(llvm::StringRef*, llvm::StringRef*,
> llvm::StringTableBuilder::finalize()::$_0&) + 3821
>
> 9 llvm-mc 0x00000001098e7d69 void
> std::__1::__sort<llvm::StringTableBuilder::finalize()::$_0&,
> llvm::StringRef*>(llvm::StringRef*, llvm::StringRef*,
> llvm::StringTableBuilder::finalize()::$_0&) + 3753
>
> 10 llvm-mc 0x00000001098e6c45
> llvm::StringTableBuilder::finalize() + 309
>
> 11 llvm-mc 0x000000010985081d (anonymous
> namespace)::ELFObjectWriter::CreateMetadataSections(llvm::MCAssembler&,
> llvm::MCAsmLayout&, llvm::DenseMap<llvm::MCSectionELF const*, unsigned int,
> llvm::DenseMapInfo<llvm::MCSectionELF const*> >&,
> llvm::DenseMap<llvm::MCSectionELF const*, llvm::MCSectionELF const*,
> llvm::DenseMapInfo<llvm::MCSectionELF const*> > const&) + 1293
>
> 12 llvm-mc 0x000000010984cf7f (anonymous
> namespace)::ELFObjectWriter::WriteObject(llvm::MCAssembler&,
> llvm::MCAsmLayout const&) + 47915 llvm-mc
> 0x00000001098abc05 llvm::MCELFStreamer::FinishImpl() + 69
>
> 16 llvm-mc 0x00000001098ce1af llvm::MCStreamer::Finish()
> + 159
>
> 17 llvm-mc 0x00000001097e6cd1 (anonymous
> namespace)::AsmParser::Run(bool, bool) + 2689
>
> 18 llvm-mc 0x000000010944aacf AssembleInput(char const*,
> llvm::Target const*, llvm::SourceMgr&, llvm::MCContext&, llvm::MCStreamer&,
> llvm::MCAsmInfo&, llvm::MCSubtargetInfo&, llvm::MCInstrInfo&,
> llvm::MCTargetOptions&) + 959
>
> 19 llvm-mc 0x0000000109448d79 main + 9977
>
> 20 libdyld.dylib 0x00007fff8c0585fd start + 1
>
> Stack dump:
>
>
> I wonder if the tests are failing because the compare function doesn't
> satisfy strict weak ordering. My understanding is that if A == B, comp(A,
> B) should return false, but I believe the compare function used in this
> patch returns true.
>
> If I check A != B before calling std::lexicographical_compare, the tests
> pass.
>
> Let me know if you need more information.
>
>
> On Wed, Sep 24, 2014 at 6:19 AM, Benjamin Kramer <benny.kra at googlemail.com
> > wrote:
>
>> Author: d0k
>> Date: Wed Sep 24 08:19:28 2014
>> New Revision: 218380
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=218380&view=rev
>> Log:
>> Replace a hand-written suffix compare with std::lexicographical_compare.
>>
>> No functionality change.
>>
>> Modified:
>> llvm/trunk/lib/MC/StringTableBuilder.cpp
>>
>> Modified: llvm/trunk/lib/MC/StringTableBuilder.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/StringTableBuilder.cpp?rev=218380&r1=218379&r2=218380&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/MC/StringTableBuilder.cpp (original)
>> +++ llvm/trunk/lib/MC/StringTableBuilder.cpp Wed Sep 24 08:19:28 2014
>> @@ -12,25 +12,17 @@
>>
>> using namespace llvm;
>>
>> -static bool compareBySuffix(StringRef a, StringRef b) {
>> - size_t sizeA = a.size();
>> - size_t sizeB = b.size();
>> - size_t len = std::min(sizeA, sizeB);
>> - for (size_t i = 0; i < len; ++i) {
>> - char ca = a[sizeA - i - 1];
>> - char cb = b[sizeB - i - 1];
>> - if (ca != cb)
>> - return ca > cb;
>> - }
>> - return sizeA > sizeB;
>> -}
>> -
>> void StringTableBuilder::finalize() {
>> SmallVector<StringRef, 8> Strings;
>> for (auto i = StringIndexMap.begin(), e = StringIndexMap.end(); i !=
>> e; ++i)
>> Strings.push_back(i->getKey());
>>
>> - std::sort(Strings.begin(), Strings.end(), compareBySuffix);
>> + // Sort the vector so a string is sorted above its suffixes.
>> + std::sort(Strings.begin(), Strings.end(), [](StringRef A, StringRef B)
>> {
>> + typedef std::reverse_iterator<StringRef::iterator> Reverse;
>> + return !std::lexicographical_compare(Reverse(A.end()),
>> Reverse(A.begin()),
>> + Reverse(B.end()),
>> Reverse(B.begin()));
>> + });
>>
>> // FIXME: Starting with a null byte is ELF specific. Generalize this
>> so we
>> // can use the class with other object formats.
>>
>>
>> _______________________________________________
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>> llvm-commits at cs.uiuc.edu
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>>
>
>
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>
--
Alexey Samsonov
vonosmas at gmail.com
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