Index: clang/lib/Basic/SourceManager.cpp
===================================================================
--- clang/lib/Basic/SourceManager.cpp
+++ clang/lib/Basic/SourceManager.cpp
@@ -1258,23 +1258,6 @@
 #include <emmintrin.h>
 #endif
 
-static LLVM_ATTRIBUTE_NOINLINE void
-ComputeLineNumbers(DiagnosticsEngine &Diag, const ContentCache &FI,
-                   llvm::BumpPtrAllocator &Alloc,
-                   const SourceManager &SM, bool &Invalid);
-static void ComputeLineNumbers(DiagnosticsEngine &Diag, const ContentCache &FI,
-                               llvm::BumpPtrAllocator &Alloc,
-                               const SourceManager &SM, bool &Invalid) {
-  // Note that calling 'getBuffer()' may lazily page in the file.
-  llvm::Optional<llvm::MemoryBufferRef> Buffer =
-      FI.getBufferOrNone(Diag, SM.getFileManager(), SourceLocation());
-  Invalid = !Buffer;
-  if (Invalid)
-    return;
-
-  FI.SourceLineCache = LineOffsetMapping::get(*Buffer, Alloc);
-}
-
 LineOffsetMapping LineOffsetMapping::get(llvm::MemoryBufferRef Buffer,
                                          llvm::BumpPtrAllocator &Alloc) {
   // Find the file offsets of all of the *physical* source lines.  This does
@@ -1340,12 +1323,15 @@
   // If this is the first use of line information for this buffer, compute the
   /// SourceLineCache for it on demand.
   if (!Content->SourceLineCache) {
-    bool MyInvalid = false;
-    ComputeLineNumbers(Diag, *Content, ContentCacheAlloc, *this, MyInvalid);
+    llvm::Optional<llvm::MemoryBufferRef> Buffer =
+        Content->getBufferOrNone(Diag, getFileManager(), SourceLocation());
     if (Invalid)
-      *Invalid = MyInvalid;
-    if (MyInvalid)
+      *Invalid = !Buffer;
+    if (!Buffer)
       return 1;
+
+    Content->SourceLineCache =
+        LineOffsetMapping::get(*Buffer, ContentCacheAlloc);
   } else if (Invalid)
     *Invalid = false;
 
@@ -1692,9 +1678,11 @@
   // If this is the first use of line information for this buffer, compute the
   // SourceLineCache for it on demand.
   if (!Content->SourceLineCache) {
-    bool MyInvalid = false;
-    ComputeLineNumbers(Diag, *Content, ContentCacheAlloc, *this, MyInvalid);
-    if (MyInvalid)
+    if (llvm::Optional<llvm::MemoryBufferRef> Buffer =
+            Content->getBufferOrNone(Diag, getFileManager(), SourceLocation()))
+      Content->SourceLineCache =
+          LineOffsetMapping::get(*Buffer, ContentCacheAlloc);
+    else
       return SourceLocation();
   }