Harden writer of munged bitcode for fuzzing

unittests/Bitcode/NaClMungedIoTest.cpp

Index: unittests/Bitcode/NaClMungedIoTest.cpp
diff --git a/unittests/Bitcode/NaClMungedIoTest.cpp b/unittests/Bitcode/NaClMungedIoTest.cpp
index 950f09be1613eee377e55760ae1e32e162bb71d4..016860dc4b086d5355b2d7991fbfa9872ff98373 100644
--- a/unittests/Bitcode/NaClMungedIoTest.cpp
+++ b/unittests/Bitcode/NaClMungedIoTest.cpp
@@ -38,12 +38,19 @@ typedef SmallVector<char, 1024> TextBuffer;
 // the text buffer. Returns a corresponding memory buffer containing
 // the munged bitcode records.
 std::unique_ptr<MemoryBuffer> writeMungedBitcode(
-    NaClMungedBitcode &Bitcode, TextBuffer &Buffer) {
-  Bitcode.write(Buffer, /* AddHeader = */ true);
+    NaClMungedBitcode &Bitcode, TextBuffer &Buffer,
+    NaClMungedBitcode::WriteFlags &Flags) {
+  Bitcode.write(Buffer, /* AddHeader = */ true, Flags);
   StringRef Input(Buffer.data(), Buffer.size());
   return MemoryBuffer::getMemBuffer(Input, "Test", false);
 }
 
+std::unique_ptr<MemoryBuffer> writeMungedBitcode(
+    NaClMungedBitcode &Bitcode, TextBuffer &Buffer) {
+  NaClMungedBitcode::WriteFlags Flags;
+  return writeMungedBitcode(Bitcode, Buffer, Flags);
+}
+
 // Write out the bitcode, parse it back, and return the resulting
 // munged bitcode.
 std::string parseWrittenMungedBitcode(NaClMungedBitcode &OutBitcode) {
@@ -160,9 +167,15 @@ TEST(NaClMungedIoTest, TestTruncatedNonalignedBitcode) {
       stringify(Bitcode));
 
   // Show that we can't write the bitcode correctly.
-  TextBuffer Buffer;
-  EXPECT_DEATH(writeMungedBitcode(Bitcode, Buffer),
-               ".*Unflushed data remaining.*");
+  TextBuffer WriteBuffer;
+  std::string LogBuffer;
+  raw_string_ostream StrBuf(LogBuffer);
+  NaClMungedBitcode::WriteFlags Flags;
+  Flags.setErrStream(StrBuf);
+  writeMungedBitcode(Bitcode, WriteBuffer, Flags);
+  EXPECT_EQ(
+      "Error (Block 8): Missing close block.\n",
+      StrBuf.str());
 }
 
 } // end of anonymous namespace