diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 61dfe35..305dcd4 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -94,11 +94,9 @@
     return Buffer.getPointer();
   }    
 
-  std::string ErrorStr;
   bool isVolatile = SM.userFilesAreVolatile() && !IsSystemFile;
-  Buffer.setPointer(SM.getFileManager().getBufferForFile(ContentsEntry,
-                                                         &ErrorStr,
-                                                         isVolatile));
+  auto BufferOrError =
+      SM.getFileManager().getBufferForFile(ContentsEntry, isVolatile);
 
   // If we were unable to open the file, then we are in an inconsistent
   // situation where the content cache referenced a file which no longer
@@ -110,27 +108,30 @@
   // currently handle returning a null entry here. Ideally we should detect
   // that we are in an inconsistent situation and error out as quickly as
   // possible.
-  if (!Buffer.getPointer()) {
-    const StringRef FillStr("<<<MISSING SOURCE FILE>>>\n");
-    Buffer.setPointer(MemoryBuffer::getNewMemBuffer(ContentsEntry->getSize(), 
-                                                    "<invalid>"));
+  if (!BufferOrError) {
+    StringRef FillStr("<<<MISSING SOURCE FILE>>>\n");
+    Buffer.setPointer(MemoryBuffer::getNewMemBuffer(ContentsEntry->getSize(),
+                                                    "<invalid>").release());
     char *Ptr = const_cast<char*>(Buffer.getPointer()->getBufferStart());
     for (unsigned i = 0, e = ContentsEntry->getSize(); i != e; ++i)
       Ptr[i] = FillStr[i % FillStr.size()];
 
     if (Diag.isDiagnosticInFlight())
-      Diag.SetDelayedDiagnostic(diag::err_cannot_open_file, 
-                                ContentsEntry->getName(), ErrorStr);
-    else 
+      Diag.SetDelayedDiagnostic(diag::err_cannot_open_file,
+                                ContentsEntry->getName(),
+                                BufferOrError.getError().message());
+    else
       Diag.Report(Loc, diag::err_cannot_open_file)
-        << ContentsEntry->getName() << ErrorStr;
+          << ContentsEntry->getName() << BufferOrError.getError().message();
 
     Buffer.setInt(Buffer.getInt() | InvalidFlag);
     
     if (Invalid) *Invalid = true;
     return Buffer.getPointer();
   }
-  
+
+  Buffer.setPointer(BufferOrError->release());
+
   // Check that the file's size is the same as in the file entry (which may
   // have come from a stat cache).
   if (getRawBuffer()->getBufferSize() != (size_t)ContentsEntry->getSize()) {
@@ -176,17 +177,11 @@
 }
 
 unsigned LineTableInfo::getLineTableFilenameID(StringRef Name) {
-  // Look up the filename in the string table, returning the pre-existing value
-  // if it exists.
-  llvm::StringMapEntry<unsigned> &Entry =
-    FilenameIDs.GetOrCreateValue(Name, ~0U);
-  if (Entry.getValue() != ~0U)
-    return Entry.getValue();
-
-  // Otherwise, assign this the next available ID.
-  Entry.setValue(FilenamesByID.size());
-  FilenamesByID.push_back(&Entry);
-  return FilenamesByID.size()-1;
+  auto IterBool =
+      FilenameIDs.insert(std::make_pair(Name, FilenamesByID.size()));
+  if (IterBool.second)
+    FilenamesByID.push_back(&*IterBool.first);
+  return IterBool.first->second;
 }
 
 /// AddLineNote - Add a line note to the line table that indicates that there
@@ -373,8 +368,7 @@
   : Diag(Diag), FileMgr(FileMgr), OverridenFilesKeepOriginalName(true),
     UserFilesAreVolatile(UserFilesAreVolatile),
     ExternalSLocEntries(nullptr), LineTable(nullptr), NumLinearScans(0),
-    NumBinaryProbes(0), FakeBufferForRecovery(nullptr),
-    FakeContentCacheForRecovery(nullptr) {
+    NumBinaryProbes(0) {
   clearIDTables();
   Diag.setSourceManager(this);
 }
@@ -398,9 +392,6 @@
       ContentCacheAlloc.Deallocate(I->second);
     }
   }
-  
-  delete FakeBufferForRecovery;
-  delete FakeContentCacheForRecovery;
 
   llvm::DeleteContainerSeconds(MacroArgsCacheMap);
 }
@@ -460,13 +451,13 @@
 
 /// createMemBufferContentCache - Create a new ContentCache for the specified
 ///  memory buffer.  This does no caching.
-const ContentCache *
-SourceManager::createMemBufferContentCache(llvm::MemoryBuffer *Buffer) {
+const ContentCache *SourceManager::createMemBufferContentCache(
+    std::unique_ptr<llvm::MemoryBuffer> Buffer) {
   // Add a new ContentCache to the MemBufferInfos list and return it.
   ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>();
   new (Entry) ContentCache();
   MemBufferInfos.push_back(Entry);
-  Entry->setBuffer(Buffer);
+  Entry->setBuffer(std::move(Buffer));
   return Entry;
 }
 
@@ -505,10 +496,10 @@
 /// fake, non-empty buffer.
 llvm::MemoryBuffer *SourceManager::getFakeBufferForRecovery() const {
   if (!FakeBufferForRecovery)
-    FakeBufferForRecovery
-      = llvm::MemoryBuffer::getMemBuffer("<<<INVALID BUFFER>>");
-  
-  return FakeBufferForRecovery;
+    FakeBufferForRecovery =
+        llvm::MemoryBuffer::getMemBuffer("<<<INVALID BUFFER>>");
+
+  return FakeBufferForRecovery.get();
 }
 
 /// \brief As part of recovering from missing or changed content, produce a
@@ -516,11 +507,11 @@
 const SrcMgr::ContentCache *
 SourceManager::getFakeContentCacheForRecovery() const {
   if (!FakeContentCacheForRecovery) {
-    FakeContentCacheForRecovery = new ContentCache();
+    FakeContentCacheForRecovery = llvm::make_unique<SrcMgr::ContentCache>();
     FakeContentCacheForRecovery->replaceBuffer(getFakeBufferForRecovery(),
                                                /*DoNotFree=*/true);
   }
-  return FakeContentCacheForRecovery;
+  return FakeContentCacheForRecovery.get();
 }
 
 /// \brief Returns the previous in-order FileID or an invalid FileID if there