[interpreter] Don't assume generator functions do an initial yield.

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index cb133c365eb053b713b31638e1c7d23ec6716668..12743039880ba0c894d81804041a71fb8c6d61b9 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -876,7 +876,10 @@ void BytecodeGenerator::VisitGeneratorPrologue() {
   BuildIndexedJump(generator_state_, 0, generator_resume_points_.size(),
                    generator_resume_points_);
 
-  builder()->Bind(&regular_call);
+  builder()
+      ->Bind(&regular_call)
+      .LoadLiteral(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting))
+      .StoreAccumulatorInRegister(generator_state_);

[Dan Ehrenberg, 2016/08/17 13:44:34]

Looks like you're doing this extra load/store for generators too, not just async
functions, is this right? Seems fine but very slightly suboptimal.

[rmcilroy, 2016/08/17 13:53:40]

+1

   // This is a regular call. Fall through to the ordinary function prologue,
   // after which we will run into the generator object creation and other extra
   // code inserted by the parser.