Implement [Generator].prototype.return.

src/full-codegen/ia32/full-codegen-ia32.cc

Index: src/full-codegen/ia32/full-codegen-ia32.cc
diff --git a/src/full-codegen/ia32/full-codegen-ia32.cc b/src/full-codegen/ia32/full-codegen-ia32.cc
index 997a3539a2827903b01ab5f7c1aa56a95d21a0e0..642aceb14384d81bb03f6132d42863b4ed2bdc28 100644
--- a/src/full-codegen/ia32/full-codegen-ia32.cc
+++ b/src/full-codegen/ia32/full-codegen-ia32.cc
@@ -1838,8 +1838,17 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
 
       __ jmp(&suspend);
       __ bind(&continuation);
+      // When we arrive here, the stack top is the resume mode and
+      // result_register() holds the input value (the argument given to the
+      // respective resume operation).
       __ RecordGeneratorContinuation();
-      __ jmp(&resume);
+      __ pop(ebx);
+      __ cmp(ebx, Immediate(Smi::FromInt(JSGeneratorObject::RETURN)));
+      __ j(not_equal, &resume);
+      __ push(result_register());
+      EmitCreateIteratorResult(true);
+      EmitUnwindBeforeReturn();
+      EmitReturnSequence();
 
       __ bind(&suspend);
       VisitForAccumulatorValue(expr->generator_object());
@@ -1868,9 +1877,6 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
 
     case Yield::kFinal: {
       VisitForAccumulatorValue(expr->generator_object());
-      __ mov(FieldOperand(result_register(),
-                          JSGeneratorObject::kContinuationOffset),
-             Immediate(Smi::FromInt(JSGeneratorObject::kGeneratorClosed)));
       // Pop value from top-of-stack slot, box result into result register.
       EmitCreateIteratorResult(true);
       EmitUnwindBeforeReturn();
@@ -1915,6 +1921,10 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
       __ jmp(&l_suspend);
       __ bind(&l_continuation);
       __ RecordGeneratorContinuation();
+      __ pop(ebx);
+      // TODO(neis): Ignoring the resume mode here is clearly wrong.  Currently,
+      // return is not supported for yield*.  The planned desugaring of yield*
+      // using do-expressions will naturally solve this.
       __ jmp(&l_resume);
 
       __ bind(&l_suspend);
@@ -2050,6 +2060,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
     __ add(edx, ecx);
     __ mov(FieldOperand(ebx, JSGeneratorObject::kContinuationOffset),
            Immediate(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
+    __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
     __ jmp(edx);
     __ bind(&slow_resume);
   }
@@ -2063,6 +2074,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
   __ push(ecx);
   __ jmp(&push_operand_holes);
   __ bind(&call_resume);
+  __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
   __ push(ebx);
   __ push(result_register());
   __ Push(Smi::FromInt(resume_mode));