[C++] Add a fast path for interning lhs of assignments

1 files changed, 9 insertions, 0 deletions

diff --git a/stmt.h b/stmt.h
index 4d4c5eb..3b6feeb 100644
--- a/stmt.h
+++ b/stmt.h
@@ -20,6 +20,7 @@
 
 #include "loc.h"
 #include "string_piece.h"
+#include "symtab.h"
 
 using namespace std;
 
@@ -85,11 +86,19 @@ struct AssignStmt : public Stmt {
   AssignOp op;
   AssignDirective directive;
 
+  AssignStmt()
+      : lhs_sym_cache_(Symbol::IsUninitialized{}) {
+  }
   virtual ~AssignStmt();
 
   virtual void Eval(Evaluator* ev) const;
 
   virtual string DebugString() const;
+
+  Symbol GetLhsSymbol(Evaluator* ev) const;
+
+ private:
+  mutable Symbol lhs_sym_cache_;
 };
 
 struct CommandStmt : public Stmt {