Index: lib/AsmParser/LLLexer.cpp
===================================================================
--- lib/AsmParser/LLLexer.cpp
+++ lib/AsmParser/LLLexer.cpp
@@ -170,19 +170,9 @@
 }
 
 int LLLexer::getNextChar() {
-  char CurChar = *CurPtr++;
-  switch (CurChar) {
-  default: return (unsigned char)CurChar;
-  case 0:
-    // A nul character in the stream is either the end of the current buffer or
-    // a random nul in the file.  Disambiguate that here.
-    if (CurPtr-1 != CurBuf.end())
-      return 0;  // Just whitespace.
-
-    // Otherwise, return end of file.
-    --CurPtr;  // Another call to lex will return EOF again.
+  if (CurPtr >= CurBuf.end())
     return EOF;
-  }
+  return (unsigned char)*CurPtr++;
 }
 
 
Index: unittests/AsmParser/AsmParserTest.cpp
===================================================================
--- /dev/null
+++ unittests/AsmParser/AsmParserTest.cpp
@@ -0,0 +1,32 @@
+//===- llvm/unittest/AsmParser/AsmParserTest.cpp - asm parser unittests ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(AsmParserTest, NonNullTerminatedInput) {
+  LLVMContext &Ctx = getGlobalContext();
+  StringRef Source = "; Empty module \n\1\2";
+  SMDiagnostic Error;
+  auto Mod =
+      parseAssemblyString(Source.substr(0, Source.size() - 2), Error, Ctx);
+
+  EXPECT_TRUE(Mod != nullptr);
+  EXPECT_TRUE(Error.getMessage().empty());
+}
+
+} // end anonymous namespace
Index: unittests/AsmParser/CMakeLists.txt
===================================================================
--- /dev/null
+++ unittests/AsmParser/CMakeLists.txt
@@ -0,0 +1,9 @@
+set(LLVM_LINK_COMPONENTS
+  AsmParser
+  Core
+  Support
+  )
+
+add_llvm_unittest(AsmParserTests
+  AsmParserTest.cpp
+  )
Index: unittests/AsmParser/Makefile
===================================================================
--- /dev/null
+++ unittests/AsmParser/Makefile
@@ -0,0 +1,15 @@
+##===- unittests/Assembler/Makefile ------------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../..
+TESTNAME = AsmParser
+LINK_COMPONENTS := AsmParser Core Support
+
+include $(LEVEL)/Makefile.config
+include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest
Index: unittests/CMakeLists.txt
===================================================================
--- unittests/CMakeLists.txt
+++ unittests/CMakeLists.txt
@@ -13,6 +13,7 @@
 
 add_subdirectory(ADT)
 add_subdirectory(Analysis)
+add_subdirectory(AsmParser)
 add_subdirectory(Bitcode)
 add_subdirectory(CodeGen)
 add_subdirectory(DebugInfo)
Index: unittests/Makefile
===================================================================
--- unittests/Makefile
+++ unittests/Makefile
@@ -9,8 +9,9 @@
 
 LEVEL = ..
 
-PARALLEL_DIRS = ADT Analysis Bitcode CodeGen DebugInfo ExecutionEngine IR \
-		LineEditor Linker MC Option ProfileData Support Transforms
+PARALLEL_DIRS = ADT Analysis AsmParser Bitcode CodeGen DebugInfo \
+                ExecutionEngine IR LineEditor Linker MC Option ProfileData \
+                Support Transforms
 
 include $(LEVEL)/Makefile.config
 include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest