SourceManager: Simplify by inlining what remains of ComputeLineNumbers, NFC

[dexonsmith]

Summary

Use LineOffsetMapping:get directly and remove/inline the helper
ComputeLineNumbers, simplifying the callers.

[dexonsmith]

Found a further simplification, removing a redundant call to ContentCache::getBufferOrNone.

clang/lib/Basic/SourceManager.cpp

unsigned SourceManager::getPresumedColumnNumber(SourceLocation Loc,
   if (isInvalid(PLoc, Invalid)) return 0;
   return PLoc.getColumn();
 }
 
 #ifdef __SSE2__
 #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
   // not look at trigraphs, escaped newlines, or anything else tricky.
   SmallVector<unsigned, 256> LineOffsets;
 
   // Line #1 starts at char 0.
   LineOffsets.push_back(0);
else {
     }
 
     Content = Entry.getFile().getContentCache();
   }
 
   // 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;
 
   // Okay, we know we have a line number table.  Do a binary search to find the
   // line number that this character position lands on.
   const unsigned *SourceLineCache = Content->SourceLineCache.begin();
   const unsigned *SourceLineCacheStart = SourceLineCache;
   const unsigned *SourceLineCacheEnd = Content->SourceLineCache.end();
SourceLocation SourceManager::translateLineCol(FileID FID,
 
   const ContentCache *Content = Entry.getFile().getContentCache();
   if (!Content)
     return SourceLocation();
 
   // 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();
   }
 
   llvm::Optional<llvm::MemoryBufferRef> Buffer =
       Content->getBufferOrNone(Diag, getFileManager());
   if (!Buffer)
     return SourceLocation();