Cache macro expander objects to avoid thrashing malloc in heavy expansion situations.

This doesn't significantly improve carbon.h, but it does speed up
INPUTS/macro_pounder_obj.c by 48%



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@39864 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index e3aff76012..4b6ea1f436 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -114,6 +114,11 @@ class Preprocessor {
   unsigned NumMacroExpanded, NumFnMacroExpanded, NumBuiltinMacroExpanded;
   unsigned NumFastMacroExpanded, NumTokenPaste, NumFastTokenPaste;
   unsigned NumSkipped;
+  
+  /// MacroExpanderCache - Cache macro expanders to reduce malloc traffic.
+  enum { MacroExpanderCacheSize = 8 };
+  unsigned NumCachedMacroExpanders;
+  MacroExpander *MacroExpanderCache[MacroExpanderCacheSize];
 public:
   Preprocessor(Diagnostic &diags, const LangOptions &opts, TargetInfo &target,
                SourceManager &SM, HeaderSearch &Headers);