set up the machinery for a MacroArgs cache hanging off Preprocessor.

We creating and free thousands of MacroArgs objects (and the related
std::vectors hanging off them) for the testcase in PR5610 even though
there are only ~20 live at a time.  This doesn't actually use the 
cache yet.

llvm-svn: 91391

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/Lex/MacroArgs.cpp b/clang/lib/Lex/MacroArgs.cpp
index a621854814f..376cce8eb32 100644
--- a/clang/lib/Lex/MacroArgs.cpp
+++ b/clang/lib/Lex/MacroArgs.cpp
@@ -48,6 +48,19 @@ void MacroArgs::destroy(Preprocessor &PP) {
   free(this);
 }
 
+/// deallocate - This should only be called by the Preprocessor when managing
+/// its freelist.
+MacroArgs *MacroArgs::deallocate() {
+  MacroArgs *Next = ArgCache;
+  
+  // Run the dtor to deallocate the vectors.
+  this->~MacroArgs();
+  // Release the memory for the object.
+  free(this);
+  
+  return Next;
+}
+
 
 /// getArgLength - Given a pointer to an expanded or unexpanded argument,
 /// return the number of tokens, not counting the EOF, that make up the