Harden writer of munged bitcode for fuzzing

include/llvm/Bitcode/NaCl/NaClBitcodeMunge.h

Index: include/llvm/Bitcode/NaCl/NaClBitcodeMunge.h
diff --git a/include/llvm/Bitcode/NaCl/NaClBitcodeMunge.h b/include/llvm/Bitcode/NaCl/NaClBitcodeMunge.h
index d9a46ab91a2c0a36225fa89fa97b9bd74a8fc0ec..15208ae50961646b6fd431cb7c77d00f29d8613c 100644
--- a/include/llvm/Bitcode/NaCl/NaClBitcodeMunge.h
+++ b/include/llvm/Bitcode/NaCl/NaClBitcodeMunge.h
@@ -73,13 +73,13 @@ public:
   }
 
   /// Creates MungedInput and DumpStream for running tests, based on
-  /// given Munges.
-  void setupTest(
+  /// given Munges. Returns true if able to set up test.
+  bool setupTest(
       const char *TestName, const uint64_t Munges[], size_t MungesSize,
       bool AddHeader);
 
-  /// Cleans up state after a test.
-  void cleanupTest();
+  /// Cleans up state after a test. Returns true if no errors found.
+  bool cleanupTest();
 
   /// Returns the resulting string generated by the corresponding test.
   const std::string &getTestResults() const {
@@ -110,6 +110,16 @@ public:
     WriteFlags.setWriteBadAbbrevIndex(NewValue);
   }
 
+  /// Get access to munged bitcodes.
+  NaClMungedBitcode &getMungedBitcode() {
+    return MungedBitcode;
+  }
+
+  /// Apply given munges to the munged bitcode.
+  void munge(const uint64_t Munges[], size_t MungesSize) {
+    MungedBitcode.munge(Munges, MungesSize, RecordTerminator);
+  }
+
 protected:
   // The bitcode records being munged.
   NaClMungedBitcode MungedBitcode;
@@ -151,6 +161,25 @@ protected:
   }
 };
 
+/// Class to run tests writing munged bitcode.
+class NaClWriteMunger : public NaClBitcodeMunger {
+public:
+  NaClWriteMunger(const uint64_t Records[], size_t RecordsSize,
+                  uint64_t RecordTerminator)
+      : NaClBitcodeMunger(Records, RecordsSize, RecordTerminator) {}
+
+  /// Writes munged bitcode and puts error messages into DumpResults.
+  /// Returns true if successful.
+  bool runTest(const char* TestName, const uint64_t Munges[],
+               size_t MungesSize);
+
+  // Same as above, but without any edits.
+  bool runTest(const char* TestName) {
+    uint64_t NoMunges[] = {0};
+    return runTest(TestName, NoMunges, 0);
+  }
+};
+
 /// Class to run tests for function llvm::NaClObjDump.
 class NaClObjDumpMunger : public NaClBitcodeMunger {
 public: