*sigh*I wish we had std::bit_cast instead of using union based type punning, we do have __builtin_bit_cast but it is different enough that replacing it later on w/ std::bit_cast wouldn’t just be search/replace.
> On May 19, 2021, at 12:37 PM, Raphael Isemann via lldb-commits > <lldb-commits@lists.llvm.org> wrote: > > > Author: Raphael Isemann > Date: 2021-05-19T21:37:10+02:00 > New Revision: 4b074b49be206306330076b9fa40632ef1960823 > > URL: > https://github.com/llvm/llvm-project/commit/4b074b49be206306330076b9fa40632ef1960823 > DIFF: > https://github.com/llvm/llvm-project/commit/4b074b49be206306330076b9fa40632ef1960823.diff > > LOG: [lldb] Fix UB in half2float and add some more tests. > > The added DumpDataExtractorTest uncovered that this is lshifting a negative > integer which upsets ubsan and breaks the sanitizer bot. This patch just > changes the variable we shift to be unsigned and adds a bunch of tests to make > sure this function does what it promises. > > Added: > > > Modified: > lldb/source/Core/DumpDataExtractor.cpp > lldb/unittests/Core/DumpDataExtractorTest.cpp > > Removed: > > > > ################################################################################ > diff --git a/lldb/source/Core/DumpDataExtractor.cpp > b/lldb/source/Core/DumpDataExtractor.cpp > index ec44e3481c1e5..34c9353c9feaa 100644 > --- a/lldb/source/Core/DumpDataExtractor.cpp > +++ b/lldb/source/Core/DumpDataExtractor.cpp > @@ -52,7 +52,9 @@ static float half2float(uint16_t half) { > float f; > uint32_t u; > } u; > - int32_t v = (int16_t)half; > + // Sign extend to 4 byte. > + int32_t sign_extended = static_cast<int16_t>(half); > + uint32_t v = static_cast<uint32_t>(sign_extended); > > if (0 == (v & 0x7c00)) { > u.u = v & 0x80007FFFU; > > diff --git a/lldb/unittests/Core/DumpDataExtractorTest.cpp > b/lldb/unittests/Core/DumpDataExtractorTest.cpp > index c4ec5f2e9a35b..05cd13add1e99 100644 > --- a/lldb/unittests/Core/DumpDataExtractorTest.cpp > +++ b/lldb/unittests/Core/DumpDataExtractorTest.cpp > @@ -174,8 +174,30 @@ TEST(DumpDataExtractorTest, Formats) { > "{0x0000000000000000 0xaaaabbbbccccdddd}"); > > // See half2float for format details. > + // Test zeroes. > + TestDump(std::vector<uint16_t>{0x0000, 0x8000}, > + lldb::Format::eFormatVectorOfFloat16, "{0 -0}"); > + // Some subnormal numbers. > + TestDump(std::vector<uint16_t>{0x0001, 0x8001}, > + lldb::Format::eFormatVectorOfFloat16, "{5.96046e-08 > -5.96046e-08}"); > + // A full mantisse and empty expontent. > + TestDump(std::vector<uint16_t>{0x83ff, 0x03ff}, > + lldb::Format::eFormatVectorOfFloat16, "{-6.09756e-05 > 6.09756e-05}"); > + // Some normal numbers. > + TestDump(std::vector<uint16_t>{0b0100001001001000}, > + lldb::Format::eFormatVectorOfFloat16, "{3.14062}"); > TestDump(std::vector<uint16_t>{0xabcd, 0x1234}, > lldb::Format::eFormatVectorOfFloat16, "{-0.0609436 0.000757217}"); > + // Largest and smallest normal number. > + TestDump(std::vector<uint16_t>{0x0400, 0x7bff}, > + lldb::Format::eFormatVectorOfFloat16, "{6.10352e-05 65504}"); > + // quiet/signaling NaNs. > + TestDump(std::vector<uint16_t>{0xffff, 0xffc0, 0x7fff, 0x7fc0}, > + lldb::Format::eFormatVectorOfFloat16, "{nan nan nan nan}"); > + // +/-Inf. > + TestDump(std::vector<uint16_t>{0xfc00, 0x7c00}, > + lldb::Format::eFormatVectorOfFloat16, "{-inf inf}"); > + > TestDump(std::vector<float>{std::numeric_limits<float>::min(), > std::numeric_limits<float>::max()}, > lldb::Format::eFormatVectorOfFloat32, "{1.17549e-38 3.40282e+38}"); > > > > _______________________________________________ > lldb-commits mailing list > lldb-commits@lists.llvm.org > https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
