First version of the new generators implementation.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 43759571fabe93f0ef1db338c1b8f0329024b773..78021d5681b1f8f19d0d7dbcad3a6ee3d54b93cc 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -506,8 +506,7 @@ bool UseIgnition(CompilationInfo* info) {
     return false;
   }
 
-  // TODO(4681): Generator functions are not yet supported.
-  if (info->shared_info()->is_generator()) {
+  if (info->shared_info()->is_generator() && !FLAG_ignition_generators) {
     return false;
   }
 
@@ -840,6 +839,13 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
     return MaybeHandle<Code>();
   }
 
+  // Do not use Crankshaft/TurboFan on a generator function.
+  // TODO(neis): Eventually enable for Turbofan.
+  if (IsGeneratorFunction(info->shared_info()->kind())) {
+    info->AbortOptimization(kGenerator);
+    return MaybeHandle<Code>();
+  }
+
   // Limit the number of times we try to optimize functions.
   const int kMaxOptCount =
       FLAG_deopt_every_n_times == 0 ? FLAG_max_opt_count : 1000;