Mark destination buffer in zlib::compress and zlib::decompress as fully
initialized.
When building LLVM with system zlib and MemorySanitizer instrumentation,
MSan does not observe memory writes in zlib code and erroneously considers
zlib output buffers as uninitialized, resulting in false use-of-uninitialized
memory reports. This change helps MSan understand the state of that memory
and prevents such reports.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222763
91177308-0d34-0410-b5e6-
96231b3b80d8
Status Res = encodeZlibReturnValue(::compress2(
(Bytef *)CompressedBuffer.data(), &CompressedSize,
(const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
Status Res = encodeZlibReturnValue(::compress2(
(Bytef *)CompressedBuffer.data(), &CompressedSize,
(const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
+ // Tell MemorySanitizer that zlib output buffer is fully initialized.
+ // This avoids a false report when running LLVM with uninstrumented ZLib.
+ __msan_unpoison(CompressedBuffer.data(), CompressedSize);
CompressedBuffer.resize(CompressedSize);
return Res;
}
CompressedBuffer.resize(CompressedSize);
return Res;
}
Status Res = encodeZlibReturnValue(::uncompress(
(Bytef *)UncompressedBuffer.data(), (uLongf *)&UncompressedSize,
(const Bytef *)InputBuffer.data(), InputBuffer.size()));
Status Res = encodeZlibReturnValue(::uncompress(
(Bytef *)UncompressedBuffer.data(), (uLongf *)&UncompressedSize,
(const Bytef *)InputBuffer.data(), InputBuffer.size()));
+ // Tell MemorySanitizer that zlib output buffer is fully initialized.
+ // This avoids a false report when running LLVM with uninstrumented ZLib.
+ __msan_unpoison(UncompressedBuffer.data(), UncompressedSize);
UncompressedBuffer.resize(UncompressedSize);
return Res;
}
UncompressedBuffer.resize(UncompressedSize);
return Res;
}