diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 92654dbe8a10a2..9a806d7c9af8d1 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -450,7 +450,7 @@ static bool loadModuleMapForModuleBuild(CompilerInstance &CI, bool IsSystem,
                            PresumedModuleMapFile))
     return true;
 
-  if (SrcMgr.getBuffer(ModuleMapID)->getBufferSize() == Offset)
+  if (SrcMgr.getBufferOrFake(ModuleMapID).getBufferSize() == Offset)
     Offset = 0;
 
   return false;
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index 77a88f696abcdd..ec5caceba20790 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -805,11 +805,9 @@ void PrintPreprocessedAction::ExecuteAction() {
   // concern, so if we scan for too long, we'll just assume the file should
   // be opened in binary mode.
   bool BinaryMode = true;
-  bool InvalidFile = false;
   const SourceManager& SM = CI.getSourceManager();
-  const llvm::MemoryBuffer *Buffer = SM.getBuffer(SM.getMainFileID(),
-                                                     &InvalidFile);
-  if (!InvalidFile) {
+  if (llvm::Optional<llvm::MemoryBufferRef> Buffer =
+          SM.getBufferOrNone(SM.getMainFileID())) {
     const char *cur = Buffer->getBufferStart();
     const char *end = Buffer->getBufferEnd();
     const char *next = (cur != end) ? cur + 1 : end;
@@ -937,12 +935,12 @@ void DumpCompilerOptionsAction::ExecuteAction() {
 void PrintDependencyDirectivesSourceMinimizerAction::ExecuteAction() {
   CompilerInstance &CI = getCompilerInstance();
   SourceManager &SM = CI.getPreprocessor().getSourceManager();
-  const llvm::MemoryBuffer *FromFile = SM.getBuffer(SM.getMainFileID());
+  llvm::MemoryBufferRef FromFile = SM.getBufferOrFake(SM.getMainFileID());
 
   llvm::SmallString<1024> Output;
   llvm::SmallVector<minimize_source_to_dependency_directives::Token, 32> Toks;
   if (minimizeSourceToDependencyDirectives(
-          FromFile->getBuffer(), Output, Toks, &CI.getDiagnostics(),
+          FromFile.getBuffer(), Output, Toks, &CI.getDiagnostics(),
           SM.getLocForStartOfFile(SM.getMainFileID()))) {
     assert(CI.getDiagnostics().hasErrorOccurred() &&
            "no errors reported for failure");
diff --git a/clang/lib/Frontend/Rewrite/HTMLPrint.cpp b/clang/lib/Frontend/Rewrite/HTMLPrint.cpp
index 982e56cebbca06..1388c2e1faab2b 100644
--- a/clang/lib/Frontend/Rewrite/HTMLPrint.cpp
+++ b/clang/lib/Frontend/Rewrite/HTMLPrint.cpp
@@ -70,7 +70,7 @@ void HTMLPrinter::HandleTranslationUnit(ASTContext &Ctx) {
   if (Entry)
     Name = Entry->getName();
   else
-    Name = R.getSourceMgr().getBuffer(FID)->getBufferIdentifier();
+    Name = R.getSourceMgr().getBufferOrFake(FID).getBufferIdentifier();
 
   html::AddLineNumbers(R, FID);
   html::AddHeaderFooterInternalBuiltinCSS(R, FID, Name);
diff --git a/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp b/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
index c0c81221b23444..9d5366bb161e54 100644
--- a/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
+++ b/clang/lib/Frontend/Rewrite/RewriteModernObjC.cpp
@@ -702,9 +702,9 @@ void RewriteModernObjC::InitializeCommon(ASTContext &context) {
 
   // Get the ID and start/end of the main file.
   MainFileID = SM->getMainFileID();
-  const llvm::MemoryBuffer *MainBuf = SM->getBuffer(MainFileID);
-  MainFileStart = MainBuf->getBufferStart();
-  MainFileEnd = MainBuf->getBufferEnd();
+  llvm::MemoryBufferRef MainBuf = SM->getBufferOrFake(MainFileID);
+  MainFileStart = MainBuf.getBufferStart();
+  MainFileEnd = MainBuf.getBufferEnd();
 
   Rewrite.setSourceMgr(Context->getSourceManager(), Context->getLangOpts());
 }
diff --git a/clang/lib/Frontend/Rewrite/RewriteObjC.cpp b/clang/lib/Frontend/Rewrite/RewriteObjC.cpp
index 990509a84b06cf..3caf9a6720626a 100644
--- a/clang/lib/Frontend/Rewrite/RewriteObjC.cpp
+++ b/clang/lib/Frontend/Rewrite/RewriteObjC.cpp
@@ -631,9 +631,9 @@ void RewriteObjC::InitializeCommon(ASTContext &context) {
 
   // Get the ID and start/end of the main file.
   MainFileID = SM->getMainFileID();
-  const llvm::MemoryBuffer *MainBuf = SM->getBuffer(MainFileID);
-  MainFileStart = MainBuf->getBufferStart();
-  MainFileEnd = MainBuf->getBufferEnd();
+  llvm::MemoryBufferRef MainBuf = SM->getBufferOrFake(MainFileID);
+  MainFileStart = MainBuf.getBufferStart();
+  MainFileEnd = MainBuf.getBufferEnd();
 
   Rewrite.setSourceMgr(Context->getSourceManager(), Context->getLangOpts());
 }