diff --git a/cmake/modules/AddSwift.cmake b/cmake/modules/AddSwift.cmake
index 5f191ce..e837cf6 100644
--- a/cmake/modules/AddSwift.cmake
+++ b/cmake/modules/AddSwift.cmake
@@ -183,12 +183,16 @@
   if(optimized OR CFLAGS_FORCE_BUILD_OPTIMIZED)
     list(APPEND result "-O2")
 
-    # Omit leaf frame pointers on x86.
-    if("${CFLAGS_ARCH}" STREQUAL "i386" OR "${CFLAGS_ARCH}" STREQUAL "i686")
-      if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
-        list(APPEND result "-momit-leaf-frame-pointer")
-      else()
-        list(APPEND result "/Oy")
+    # Omit leaf frame pointers on x86 production builds (optimized, no debug
+    # info, and no asserts).
+    is_build_type_with_debuginfo("${CFLAGS_BUILD_TYPE}" debug)
+    if(NOT debug AND NOT CFLAGS_ENABLE_ASSERTIONS)
+      if("${CFLAGS_ARCH}" STREQUAL "i386" OR "${CFLAGS_ARCH}" STREQUAL "i686")
+        if(NOT SWIFT_COMPILER_IS_MSVC_LIKE)
+          list(APPEND result "-momit-leaf-frame-pointer")
+        else()
+          list(APPEND result "/Oy")
+        endif()
       endif()
     endif()
   else()
diff --git a/include/swift/Parse/Parser.h b/include/swift/Parse/Parser.h
index 6e67e55..599aec4 100644
--- a/include/swift/Parse/Parser.h
+++ b/include/swift/Parse/Parser.h
@@ -1444,7 +1444,8 @@
                    const SourceManager &SM,
                    unsigned BufferID,
                    unsigned Offset = 0,
-                   unsigned EndOffset = 0);
+                   unsigned EndOffset = 0,
+                   DiagnosticEngine *Diags = nullptr);
 } // end namespace swift
 
 #endif
diff --git a/include/swift/Subsystems.h b/include/swift/Subsystems.h
index 36ade9a..caf4ca8 100644
--- a/include/swift/Subsystems.h
+++ b/include/swift/Subsystems.h
@@ -128,6 +128,7 @@
   std::vector<Token> tokenize(const LangOptions &LangOpts,
                               const SourceManager &SM, unsigned BufferID,
                               unsigned Offset = 0, unsigned EndOffset = 0,
+                              DiagnosticEngine *Diags = nullptr,
                               bool KeepComments = true,
                               bool TokenizeInterpolatedString = true,
                               ArrayRef<Token> SplitTokens = ArrayRef<Token>());
diff --git a/include/swift/SwiftRemoteMirror/CMakeLists.txt b/include/swift/SwiftRemoteMirror/CMakeLists.txt
index bbaba07..69d8450 100644
--- a/include/swift/SwiftRemoteMirror/CMakeLists.txt
+++ b/include/swift/SwiftRemoteMirror/CMakeLists.txt
@@ -1,9 +1,12 @@
 set(swift_remote_mirror_headers)
 list(APPEND swift_remote_mirror_headers
-  "MemoryReaderInterface.h"
-  "SwiftRemoteMirror.h"
-  "SwiftRemoteMirrorTypes.h")
+       MemoryReaderInterface.h
+       Platform.h
+       SwiftRemoteMirror.h
+       SwiftRemoteMirrorTypes.h)
 swift_install_in_component("swift-remote-mirror-headers"
-  FILES ${swift_remote_mirror_headers}
-  DESTINATION "include/swift/SwiftRemoteMirror")
+                           FILES
+                             ${swift_remote_mirror_headers}
+                           DESTINATION
+                             "include/swift/SwiftRemoteMirror")
 
diff --git a/include/swift/SwiftRemoteMirror/Platform.h b/include/swift/SwiftRemoteMirror/Platform.h
new file mode 100644
index 0000000..5353344
--- /dev/null
+++ b/include/swift/SwiftRemoteMirror/Platform.h
@@ -0,0 +1,45 @@
+//===-- SwiftRemoteMirror/Platform.h - Remote Mirror Platform --*-- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_REMOTE_MIRROR_PLATFORM_H
+#define SWIFT_REMOTE_MIRROR_PLATFORM_H
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+#if defined(swiftRemoteMirror_EXPORTS)
+# if defined(__ELF__)
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("protected")))
+# elif defined(__MACH__)
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
+# else
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllexport)
+# endif
+#else
+# if defined(__ELF__)
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
+# elif defined(__MACH__)
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __attribute__((__visibility__("default")))
+# else
+#   define SWIFT_REMOTE_MIRROR_LINKAGE __declspec(dllimport)
+# endif
+#endif
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+
+
+
diff --git a/include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h b/include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h
index 81e0a13..1909b94 100644
--- a/include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h
+++ b/include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h
@@ -20,6 +20,7 @@
 #ifndef SWIFT_REFLECTION_SWIFT_REFLECTION_H
 #define SWIFT_REFLECTION_SWIFT_REFLECTION_H
 
+#include "Platform.h"
 #include "MemoryReaderInterface.h"
 #include "SwiftRemoteMirrorTypes.h"
 
@@ -37,34 +38,34 @@
 #endif
 
 /// Get the metadata version supported by the Remote Mirror library.
-uint16_t
-swift_reflection_getSupportedMetadataVersion();
+SWIFT_REMOTE_MIRROR_LINKAGE
+uint16_t swift_reflection_getSupportedMetadataVersion();
 
 /// \returns An opaque reflection context.
+SWIFT_REMOTE_MIRROR_LINKAGE
 SwiftReflectionContextRef
-swift_reflection_createReflectionContext(
-    void *ReaderContext,
-    PointerSizeFunction getPointerSize,
-    SizeSizeFunction getSizeSize,
-    ReadBytesFunction readBytes,
-    GetStringLengthFunction getStringLength,
-    GetSymbolAddressFunction getSymbolAddress);
+swift_reflection_createReflectionContext(void *ReaderContext,
+                                         PointerSizeFunction getPointerSize,
+                                         SizeSizeFunction getSizeSize,
+                                         ReadBytesFunction readBytes,
+                                         GetStringLengthFunction getStringLength,
+                                         GetSymbolAddressFunction getSymbolAddress);
 
 /// Destroys an opaque reflection context.
+SWIFT_REMOTE_MIRROR_LINKAGE
 void
 swift_reflection_destroyReflectionContext(SwiftReflectionContextRef Context);
 
 /// Add reflection sections for a loaded Swift image.
-void
-swift_reflection_addReflectionInfo(SwiftReflectionContextRef ContextRef,
-                                   swift_reflection_info_t Info);
-
+SWIFT_REMOTE_MIRROR_LINKAGE
+void swift_reflection_addReflectionInfo(SwiftReflectionContextRef ContextRef,
+                                        swift_reflection_info_t Info);
 
 /// Returns a boolean indicating if the isa mask was successfully
 /// read, in which case it is stored in the isaMask out parameter.
-int
-swift_reflection_readIsaMask(SwiftReflectionContextRef ContextRef,
-                             uintptr_t *outIsaMask);
+SWIFT_REMOTE_MIRROR_LINKAGE
+int swift_reflection_readIsaMask(SwiftReflectionContextRef ContextRef,
+                                 uintptr_t *outIsaMask);
 
 /// Returns an opaque type reference for a metadata pointer, or
 /// NULL if one can't be constructed.
@@ -72,6 +73,7 @@
 /// This function loses information; in particular, passing the
 /// result to swift_reflection_infoForTypeRef() will not give
 /// the same result as calling swift_reflection_infoForMetadata().
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeref_t
 swift_reflection_typeRefForMetadata(SwiftReflectionContextRef ContextRef,
                                     uintptr_t Metadata);
@@ -82,11 +84,13 @@
 /// This function loses information; in particular, passing the
 /// result to swift_reflection_infoForTypeRef() will not give
 /// the same result as calling swift_reflection_infoForInstance().
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeref_t
 swift_reflection_typeRefForInstance(SwiftReflectionContextRef ContextRef,
                                     uintptr_t Object);
 
 /// Returns a typeref from a mangled type name string.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeref_t
 swift_reflection_typeRefForMangledTypeName(SwiftReflectionContextRef ContextRef,
                                            const char *MangledName,
@@ -94,47 +98,52 @@
 
 /// Returns a structure describing the layout of a value of a typeref.
 /// For classes, this returns the reference value itself.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeinfo_t
 swift_reflection_infoForTypeRef(SwiftReflectionContextRef ContextRef,
                                 swift_typeref_t OpaqueTypeRef);
 
 /// Returns the information about a child field of a value by index.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_childinfo_t
 swift_reflection_childOfTypeRef(SwiftReflectionContextRef ContextRef,
-                                swift_typeref_t OpaqueTypeRef,
-                                unsigned Index);
+                                swift_typeref_t OpaqueTypeRef, unsigned Index);
 
 /// Returns a structure describing the layout of a class instance
 /// from the isa pointer of a class.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeinfo_t
 swift_reflection_infoForMetadata(SwiftReflectionContextRef ContextRef,
                                  uintptr_t Metadata);
 
 /// Returns the information about a child field of a class instance
 /// by index.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_childinfo_t
 swift_reflection_childOfMetadata(SwiftReflectionContextRef ContextRef,
-                                 uintptr_t Metadata,
-                                 unsigned Index);
+                                 uintptr_t Metadata, unsigned Index);
 
 /// Returns a structure describing the layout of a class or closure
 /// context instance, from a pointer to the object itself.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeinfo_t
 swift_reflection_infoForInstance(SwiftReflectionContextRef ContextRef,
                                  uintptr_t Object);
 
 /// Returns the information about a child field of a class or closure
 /// context instance.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_childinfo_t
 swift_reflection_childOfInstance(SwiftReflectionContextRef ContextRef,
-                                 uintptr_t Object,
-                                 unsigned Index);
+                                 uintptr_t Object, unsigned Index);
 
 /// Returns the number of generic arguments of a typeref.
+SWIFT_REMOTE_MIRROR_LINKAGE
 unsigned
 swift_reflection_genericArgumentCountOfTypeRef(swift_typeref_t OpaqueTypeRef);
 
 /// Returns a fully instantiated typeref for a generic argument by index.
+SWIFT_REMOTE_MIRROR_LINKAGE
 swift_typeref_t
 swift_reflection_genericArgumentOfTypeRef(swift_typeref_t OpaqueTypeRef,
                                           unsigned Index);
@@ -158,6 +167,7 @@
 ///
 /// Returns true if InstanceTypeRef and StartOfInstanceData contain valid
 /// valid values.
+SWIFT_REMOTE_MIRROR_LINKAGE
 int swift_reflection_projectExistential(SwiftReflectionContextRef ContextRef,
                                         swift_addr_t ExistentialAddress,
                                         swift_typeref_t ExistentialTypeRef,
@@ -165,17 +175,21 @@
                                         swift_addr_t *OutStartOfInstanceData);
 
 /// Dump a brief description of the typeref as a tree to stderr.
+SWIFT_REMOTE_MIRROR_LINKAGE
 void swift_reflection_dumpTypeRef(swift_typeref_t OpaqueTypeRef);
 
 /// Dump information about the layout for a typeref.
+SWIFT_REMOTE_MIRROR_LINKAGE
 void swift_reflection_dumpInfoForTypeRef(SwiftReflectionContextRef ContextRef,
                                          swift_typeref_t OpaqueTypeRef);
 
 /// Dump information about the layout of a class instance from its isa pointer.
+SWIFT_REMOTE_MIRROR_LINKAGE
 void swift_reflection_dumpInfoForMetadata(SwiftReflectionContextRef ContextRef,
                                           uintptr_t Metadata);
 
 /// Dump information about the layout of a class or closure context instance.
+SWIFT_REMOTE_MIRROR_LINKAGE
 void swift_reflection_dumpInfoForInstance(SwiftReflectionContextRef ContextRef,
                                           uintptr_t Object);
 
@@ -186,10 +200,9 @@
 ///
 /// Returns the length of the demangled string this function tried to copy
 /// into `OutDemangledName`.
-size_t swift_reflection_demangle(const char *MangledName,
-                                 size_t Length,
-                                 char *OutDemangledName,
-                                 size_t MaxLength);
+SWIFT_REMOTE_MIRROR_LINKAGE
+size_t swift_reflection_demangle(const char *MangledName, size_t Length,
+                                 char *OutDemangledName, size_t MaxLength);
 
 #ifdef __cplusplus
 } // extern "C"
diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index 5044e91..f3c7858 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -45,6 +45,7 @@
 template <typename DF>
 void tokenize(const LangOptions &LangOpts, const SourceManager &SM,
               unsigned BufferID, unsigned Offset, unsigned EndOffset,
+              DiagnosticEngine * Diags,
               CommentRetentionMode RetainComments,
               TriviaRetentionMode TriviaRetention,
               bool TokenizeInterpolatedString, ArrayRef<Token> SplitTokens,
@@ -56,7 +57,7 @@
   if (Offset == 0 && EndOffset == 0)
     EndOffset = SM.getRangeForBuffer(BufferID).getByteLength();
 
-  Lexer L(LangOpts, SM, BufferID, /*Diags=*/nullptr, /*InSILMode=*/false,
+  Lexer L(LangOpts, SM, BufferID, Diags, /*InSILMode=*/false,
           RetainComments, TriviaRetention, Offset, EndOffset);
 
   auto TokComp = [&](const Token &A, const Token &B) {
@@ -260,6 +261,7 @@
 
       std::vector<Token> NewTokens = swift::tokenize(LangOpts, SM, BufID,
                                                      Offset, EndOffset,
+                                                     /*Diags=*/nullptr,
                                                      /*KeepComments=*/true);
       Toks.insert(Toks.end(), NewTokens.begin(), NewTokens.end());
 
@@ -278,12 +280,14 @@
 std::vector<Token> swift::tokenize(const LangOptions &LangOpts,
                                    const SourceManager &SM, unsigned BufferID,
                                    unsigned Offset, unsigned EndOffset,
+                                   DiagnosticEngine *Diags,
                                    bool KeepComments,
                                    bool TokenizeInterpolatedString,
                                    ArrayRef<Token> SplitTokens) {
   std::vector<Token> Tokens;
 
   tokenize(LangOpts, SM, BufferID, Offset, EndOffset,
+           Diags,
            KeepComments ? CommentRetentionMode::ReturnAsTokens
                         : CommentRetentionMode::AttachToNextToken,
            TriviaRetentionMode::WithoutTrivia, TokenizeInterpolatedString,
@@ -299,13 +303,15 @@
 std::vector<std::pair<RC<syntax::RawSyntax>, syntax::AbsolutePosition>>
 swift::tokenizeWithTrivia(const LangOptions &LangOpts, const SourceManager &SM,
                           unsigned BufferID, unsigned Offset,
-                          unsigned EndOffset) {
+                          unsigned EndOffset,
+                          DiagnosticEngine *Diags) {
   std::vector<std::pair<RC<syntax::RawSyntax>, syntax::AbsolutePosition>>
       Tokens;
   syntax::AbsolutePosition RunningPos;
 
   tokenize(
       LangOpts, SM, BufferID, Offset, EndOffset,
+      Diags,
       CommentRetentionMode::AttachToNextToken, TriviaRetentionMode::WithTrivia,
       /*TokenizeInterpolatedString=*/false,
       /*SplitTokens=*/ArrayRef<Token>(),
diff --git a/lib/SIL/SILPrinter.cpp b/lib/SIL/SILPrinter.cpp
index ab86919..357f728 100644
--- a/lib/SIL/SILPrinter.cpp
+++ b/lib/SIL/SILPrinter.cpp
@@ -2634,7 +2634,7 @@
   }
   
   OS << "\n\nimport Builtin\nimport " << STDLIB_NAME
-     << "\nimport SwiftShims" << "\n\n";
+     << "\nimport " << SWIFT_SHIMS_NAME << "\n\n";
 
   // Print the declarations and types from the associated context (origin module or
   // current file).
diff --git a/stdlib/public/SwiftRemoteMirror/CMakeLists.txt b/stdlib/public/SwiftRemoteMirror/CMakeLists.txt
index bacdf0d..93255e9 100644
--- a/stdlib/public/SwiftRemoteMirror/CMakeLists.txt
+++ b/stdlib/public/SwiftRemoteMirror/CMakeLists.txt
@@ -4,10 +4,15 @@
 # libswiftRemoteMirror.dylib should not have runtime dependencies; it's
 # always built as a shared library.
 if(SWIFT_BUILD_DYNAMIC_STDLIB OR SWIFT_BUILD_REMOTE_MIRROR)
-  add_swift_library(swiftRemoteMirror SHARED TARGET_LIBRARY DONT_EMBED_BITCODE NOSWIFTRT
-      SwiftRemoteMirror.cpp
-      LINK_LIBRARIES swiftReflection
-      C_COMPILE_FLAGS ${SWIFT_RUNTIME_CXX_FLAGS}
-      LINK_FLAGS ${SWIFT_RUNTIME_LINK_FLAGS}
-      INSTALL_IN_COMPONENT swift-remote-mirror)
+  add_swift_library(swiftRemoteMirror
+                    SHARED TARGET_LIBRARY DONT_EMBED_BITCODE NOSWIFTRT
+                    SwiftRemoteMirror.cpp
+                    LINK_LIBRARIES
+                      swiftReflection
+                    C_COMPILE_FLAGS
+                      ${SWIFT_RUNTIME_CXX_FLAGS} -DswiftRemoteMirror_EXPORTS
+                    LINK_FLAGS
+                      ${SWIFT_RUNTIME_LINK_FLAGS}
+                    INSTALL_IN_COMPONENT
+                      swift-remote-mirror)
 endif()
diff --git a/test/Driver/batch_mode_parseable_output.swift b/test/Driver/batch_mode_parseable_output.swift
index 7fc46d4..9930968 100644
--- a/test/Driver/batch_mode_parseable_output.swift
+++ b/test/Driver/batch_mode_parseable_output.swift
@@ -2,7 +2,7 @@
 // RUN: touch %t/file-01.swift %t/file-02.swift %t/file-03.swift
 // RUN: echo 'public func main() {}' >%t/main.swift
 //
-// RUN: %swiftc_driver -enable-batch-mode -Xfrontend -bypass-batch-mode-checks -parseable-output -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift 2>&1 | %FileCheck %s
+// RUN: %swiftc_driver -enable-batch-mode -parseable-output -c -emit-module -module-name main -j 2 %t/file-01.swift %t/file-02.swift %t/file-03.swift %t/main.swift 2>&1 | %FileCheck %s
 //
 //
 // CHECK: {{[1-9][0-9]*}}
diff --git a/test/Driver/sanitize_coverage.swift b/test/Driver/sanitize_coverage.swift
index 71f4a0b..d18574c 100644
--- a/test/Driver/sanitize_coverage.swift
+++ b/test/Driver/sanitize_coverage.swift
@@ -2,6 +2,7 @@
 // RUN: %swiftc_driver -driver-print-jobs -sanitize-coverage=func -sanitize=address %s | %FileCheck -check-prefix=SANCOV_FUNC %s
 // RUN: %swiftc_driver -driver-print-jobs -sanitize-coverage=bb -sanitize=address %s | %FileCheck -check-prefix=SANCOV_BB %s
 // RUN: %swiftc_driver -driver-print-jobs -sanitize-coverage=edge -sanitize=address %s | %FileCheck -check-prefix=SANCOV_EDGE %s
+// REQUIRES: asan_runtime
 
 // Try some options
 // RUN: %swiftc_driver -driver-print-jobs -sanitize-coverage=edge,indirect-calls,trace-bb,trace-cmp,8bit-counters  -sanitize=address %s | %FileCheck -check-prefix=SANCOV_EDGE_WITH_OPTIONS %s
diff --git a/test/Frontend/batch-mode.swift b/test/Frontend/batch-mode.swift
index 8706761f..d407dad 100644
--- a/test/Frontend/batch-mode.swift
+++ b/test/Frontend/batch-mode.swift
@@ -3,7 +3,7 @@
 // RUN: echo 'public func b() { }' >%t/b.swift
 // RUN: echo 'public func c() { }' >%t/c.swift
 // RUN: echo 'public func main() {a(); b(); c()}' >%t/main.swift
-// RUN: %target-swift-frontend -c -enable-batch-mode -bypass-batch-mode-checks -module-name foo -primary-file %t/a.swift -primary-file %t/b.swift -primary-file %t/c.swift -primary-file %t/main.swift -o %t/a.o -o %t/b.o -o %t/c.o -o %t/main.o
+// RUN: %target-swift-frontend -c -enable-batch-mode -module-name foo -primary-file %t/a.swift -primary-file %t/b.swift -primary-file %t/c.swift -primary-file %t/main.swift -o %t/a.o -o %t/b.o -o %t/c.o -o %t/main.o
 //
 // RUN: llvm-objdump -t %t/a.o | swift-demangle | %FileCheck -check-prefix=CHECK-A %s
 // RUN: llvm-objdump -t %t/b.o | swift-demangle | %FileCheck -check-prefix=CHECK-B %s
diff --git a/test/Frontend/dependencies-selective-supplementaries.swift b/test/Frontend/dependencies-selective-supplementaries.swift
index 016fc9c..c1cd4bc 100644
--- a/test/Frontend/dependencies-selective-supplementaries.swift
+++ b/test/Frontend/dependencies-selective-supplementaries.swift
@@ -5,7 +5,7 @@
 // RUN: %empty-directory(%t)
 // RUN: echo 'public func a() { }' >%t/a.swift
 // RUN: echo 'public func main() {a()}' >%t/main.swift
-// RUN: %target-swift-frontend -c -enable-batch-mode -bypass-batch-mode-checks -module-name foo -primary-file %t/a.swift -primary-file %t/main.swift -emit-dependencies-path %t/a.d -emit-dependencies-path %t/main.d  -o %t/a.o -o %t/main.o -emit-module-path %t/a.swiftmodule -emit-module-path %t/main.swiftmodule
+// RUN: %target-swift-frontend -c -enable-batch-mode -module-name foo -primary-file %t/a.swift -primary-file %t/main.swift -emit-dependencies-path %t/a.d -emit-dependencies-path %t/main.d  -o %t/a.o -o %t/main.o -emit-module-path %t/a.swiftmodule -emit-module-path %t/main.swiftmodule
 // RUN: %FileCheck -check-prefix=CHECK-MAIN %s <%t/main.d
 // RUN: %FileCheck -check-prefix=NEGATIVE-MAIN %s <%t/main.d
 //
diff --git a/test/Syntax/lexer_invalid_nul.swift b/test/Syntax/lexer_invalid_nul.swift
new file mode 100644
index 0000000..dfd1577
--- /dev/null
+++ b/test/Syntax/lexer_invalid_nul.swift
@@ -0,0 +1,5 @@
+// RUN: cat %s | tr '\132' '\0' > %t
+// RUN: %swift-syntax-test -input-source-filename %t -dump-full-tokens 2>&1 >/dev/null | %FileCheck %t
+
+// CHECK: 5:18: warning: nul character embedded in middle of file
+let a = 3 // nul(Z)
\ No newline at end of file
diff --git a/tools/swift-syntax-test/swift-syntax-test.cpp b/tools/swift-syntax-test/swift-syntax-test.cpp
index f4d00a9..3f4e8b0 100644
--- a/tools/swift-syntax-test/swift-syntax-test.cpp
+++ b/tools/swift-syntax-test/swift-syntax-test.cpp
@@ -112,11 +112,13 @@
 int getTokensFromFile(unsigned BufferID,
                       LangOptions &LangOpts,
                       SourceManager &SourceMgr,
-                      DiagnosticEngine &Diags,
+                      swift::DiagnosticEngine &Diags,
                       std::vector<std::pair<RC<syntax::RawSyntax>,
                       syntax::AbsolutePosition>> &Tokens) {
-  Tokens = tokenizeWithTrivia(LangOpts, SourceMgr, BufferID);
-  return Diags.hadAnyError() ? EXIT_FAILURE : EXIT_SUCCESS;
+  Tokens = tokenizeWithTrivia(LangOpts, SourceMgr, BufferID,
+                              /*Offset=*/0, /*EndOffset=*/0,
+                              &Diags);
+  return EXIT_SUCCESS;
 }
 
 
@@ -191,7 +193,7 @@
     TokAndPos.first->print(llvm::outs(), {});
   }
 
-  return Diags.hadAnyError() ? EXIT_FAILURE : EXIT_SUCCESS;
+  return EXIT_SUCCESS;
 }
 
 int doDumpRawTokenSyntax(const StringRef InputFilename) {
@@ -215,7 +217,7 @@
     llvm::outs() << "\n";
   }
 
-  return Diags.hadAnyError() ? EXIT_FAILURE : EXIT_SUCCESS;
+  return EXIT_SUCCESS;
 }
 
 int doFullParseRoundTrip(const char *MainExecutablePath,
diff --git a/unittests/Parse/LexerTests.cpp b/unittests/Parse/LexerTests.cpp
index 76172d8..c64aa40 100644
--- a/unittests/Parse/LexerTests.cpp
+++ b/unittests/Parse/LexerTests.cpp
@@ -35,7 +35,7 @@
     if (KeepEOF)
       Toks = tokenizeAndKeepEOF(BufID);
     else
-      Toks = tokenize(LangOpts, SourceMgr, BufID, 0, 0, KeepComments);
+      Toks = tokenize(LangOpts, SourceMgr, BufID, 0, 0, /*Diags=*/nullptr, KeepComments);
     EXPECT_EQ(ExpectedTokens.size(), Toks.size());
     for (unsigned i = 0, e = ExpectedTokens.size(); i != e; ++i) {
       EXPECT_EQ(ExpectedTokens[i], Toks[i].getKind()) << "i = " << i;
@@ -685,7 +685,7 @@
 TEST_F(LexerTest, NoPlaceholder) {
   auto checkTok = [&](StringRef Source) {
     unsigned BufID = SourceMgr.addMemBufferCopy(Source);
-    std::vector<Token> Toks = tokenize(LangOpts, SourceMgr, BufID, 0, 0, false);
+    std::vector<Token> Toks = tokenize(LangOpts, SourceMgr, BufID, 0, 0, /*Diags=*/nullptr, false);
     ASSERT_FALSE(Toks.empty());
     EXPECT_NE(tok::identifier, Toks[0].getKind());
   };
diff --git a/unittests/Parse/TokenizerTests.cpp b/unittests/Parse/TokenizerTests.cpp
index 42b8166..cb9a12f 100644
--- a/unittests/Parse/TokenizerTests.cpp
+++ b/unittests/Parse/TokenizerTests.cpp
@@ -98,6 +98,7 @@
                            BufID, 
                            /* Offset = */ 0,
                            /* EndOffset = */ 0,
+                           /* Diags = */nullptr,
                            /* KeepComments = */ true,
                            /* TokenizeInterpolatedString = */ true,
                            SplitTokens);