From b4c1c28c6e1b8d9b7a1c6a9e62e46bb93bd3ef40 Mon Sep 17 00:00:00 2001 From: Derek Schuff Date: Mon, 3 Aug 2015 18:01:50 +0000 Subject: Fix testing for end of stream in bitstream reader. This fixes a bug found while working on the bitcode reader. In particular, the method BitstreamReader::AtEndOfStream doesn't always behave correctly when processing a data streamer. The method fillCurWord doesn't properly set CurWord/BitsInCurWord if the data streamer was already at eof, but GetBytes had not yet set the ObjectSize field of the streaming memory object. This patch fixes this problem, and provides a test to show that this problem has been fixed. Patch by Karl Schimpf. Differential Revision: http://reviews.llvm.org/D11391 llvm-svn: 243890 --- llvm/unittests/Bitcode/BitReaderTest.cpp | 35 ++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'llvm/unittests/Bitcode/BitReaderTest.cpp') diff --git a/llvm/unittests/Bitcode/BitReaderTest.cpp b/llvm/unittests/Bitcode/BitReaderTest.cpp index 3c56ea04c74..d9e207e9ba3 100644 --- a/llvm/unittests/Bitcode/BitReaderTest.cpp +++ b/llvm/unittests/Bitcode/BitReaderTest.cpp @@ -10,6 +10,7 @@ #include "llvm/ADT/SmallString.h" #include "llvm/ADT/STLExtras.h" #include "llvm/AsmParser/Parser.h" +#include "llvm/Bitcode/BitstreamReader.h" #include "llvm/Bitcode/BitstreamWriter.h" #include "llvm/Bitcode/ReaderWriter.h" #include "llvm/IR/Constants.h" @@ -21,6 +22,7 @@ #include "llvm/Support/Debug.h" #include "llvm/Support/MemoryBuffer.h" #include "llvm/Support/SourceMgr.h" +#include "llvm/Support/StreamingMemoryObject.h" #include "gtest/gtest.h" using namespace llvm; @@ -89,6 +91,39 @@ getStreamedModuleFromAssembly(LLVMContext &Context, SmallString<1024> &Mem, return std::move(ModuleOrErr.get()); } +// Checks if we correctly detect eof if we try to read N bits when there are not +// enough bits left on the input stream to read N bits, and we are using a data +// streamer. In particular, it checks if we properly set the object size when +// the eof is reached under such conditions. +TEST(BitReaderTest, TestForEofAfterReadFailureOnDataStreamer) { + // Note: Because StreamingMemoryObject does a call to method GetBytes in it's + // constructor, using internal constant kChunkSize, we must fill the input + // with more characters than that amount. + static size_t InputSize = StreamingMemoryObject::kChunkSize + 5; + char *Text = new char[InputSize]; + std::memset(Text, 'a', InputSize); + Text[InputSize - 1] = '\0'; + StringRef Input(Text); + + // Build bitsteam reader using data streamer. + auto MemoryBuf = MemoryBuffer::getMemBuffer(Input); + std::unique_ptr Streamer( + new BufferDataStreamer(std::move(MemoryBuf))); + auto OwnedBytes = + llvm::make_unique(std::move(Streamer)); + auto Reader = llvm::make_unique(std::move(OwnedBytes)); + BitstreamCursor Cursor; + Cursor.init(Reader.get()); + + // Jump to two bytes before end of stream. + Cursor.JumpToBit((InputSize - 4) * CHAR_BIT); + // Try to read 4 bytes when only 2 are present, resulting in error value 0. + constexpr size_t ReadErrorValue = 0; + EXPECT_EQ(ReadErrorValue, Cursor.Read(32)); + // Should be at eof now. + EXPECT_TRUE(Cursor.AtEndOfStream()); +} + TEST(BitReaderTest, MateralizeForwardRefWithStream) { SmallString<1024> Mem; -- cgit v1.2.3