If we are past tok::eof and in caching lex mode, avoid caching repeated tok::eofs.

llvm-svn: 108175

1 files changed, 12 insertions, 4 deletions

diff --git a/clang/lib/Lex/PPCaching.cpp b/clang/lib/Lex/PPCaching.cpp
index 20e3b3dd9d8..16fcaa365cb 100644
--- a/clang/lib/Lex/PPCaching.cpp
+++ b/clang/lib/Lex/PPCaching.cpp
@@ -45,13 +45,19 @@ void Preprocessor::Backtrack() {
 }
 
 void Preprocessor::CachingLex(Token &Result) {
+  if (!InCachingLexMode())
+    return;
+
   if (CachedLexPos < CachedTokens.size()) {
     Result = CachedTokens[CachedLexPos++];
     return;
   }
 
   ExitCachingLexMode();
-  Lex(Result);
+  // True if we consumed everything already.
+  bool PastEOF =  CurPPLexer == 0 && CurTokenLexer == 0;
+  if (!PastEOF)
+    Lex(Result);
 
   if (!isBacktrackEnabled()) {
     // All cached tokens were consumed.
@@ -60,10 +66,12 @@ void Preprocessor::CachingLex(Token &Result) {
     return;
   }
 
-  // Cache the lexed token.
+  // Cache the lexed token if it's not a repeated tok::eof.
   EnterCachingLexMode();
-  CachedTokens.push_back(Result);
-  ++CachedLexPos;
+  if (!PastEOF) {
+    CachedTokens.push_back(Result);
+    ++CachedLexPos;
+  }
 }
 
 void Preprocessor::EnterCachingLexMode() {