Add a fast-path in getSpelling for identifiers.

llvm-svn: 38672

1 files changed, 7 insertions, 5 deletions

diff --git a/clang/Basic/SourceManager.cpp b/clang/Basic/SourceManager.cpp
index 762848f9f9c..ce5e5f776d0 100644
--- a/clang/Basic/SourceManager.cpp
+++ b/clang/Basic/SourceManager.cpp
@@ -128,12 +128,14 @@ SourceLocation SourceManager::getInstantiationLoc(SourceLocation PhysLoc,
 
 
 /// getCharacterData - Return a pointer to the start of the specified location
-/// in the appropriate SourceBuffer.  This returns null if it cannot be
-/// computed (e.g. invalid SourceLocation).
+/// in the appropriate SourceBuffer.
 const char *SourceManager::getCharacterData(SourceLocation SL) const {
-  if (unsigned FileID = SL.getFileID())
-    return getFileInfo(FileID)->Buffer->getBufferStart() + getFilePos(SL);
-  return 0;
+  // Note that this is a hot function in the getSpelling() path, which is
+  // heavily used by -E mode.
+  unsigned FileID = SL.getFileID();
+  assert(FileID && "Invalid source location!");
+  
+  return getFileInfo(FileID)->Buffer->getBufferStart() + getFilePos(SL);
 }
 
 /// getIncludeLoc - Return the location of the #include for the specified