Implement [Generator].prototype.return.

src/full-codegen/arm/full-codegen-arm.cc

Index: src/full-codegen/arm/full-codegen-arm.cc
diff --git a/src/full-codegen/arm/full-codegen-arm.cc b/src/full-codegen/arm/full-codegen-arm.cc
index cac5e6e7c3c9057cb9c2be61cdfd28efbc10bb5e..3faab7bf19f3b3edc14e4ddbe6c7169310688923 100644
--- a/src/full-codegen/arm/full-codegen-arm.cc
+++ b/src/full-codegen/arm/full-codegen-arm.cc
@@ -1928,8 +1928,17 @@ 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(r1);
+      __ cmp(r1, Operand(Smi::FromInt(JSGeneratorObject::RETURN)));
+      __ b(ne, &resume);
+      __ push(result_register());
+      EmitCreateIteratorResult(true);
+      EmitUnwindBeforeReturn();
+      EmitReturnSequence();
 
       __ bind(&suspend);
       VisitForAccumulatorValue(expr->generator_object());
@@ -1957,9 +1966,6 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
 
     case Yield::kFinal: {
       VisitForAccumulatorValue(expr->generator_object());
-      __ mov(r1, Operand(Smi::FromInt(JSGeneratorObject::kGeneratorClosed)));
-      __ str(r1, FieldMemOperand(result_register(),
-                                 JSGeneratorObject::kContinuationOffset));
       // Pop value from top-of-stack slot, box result into result register.
       EmitCreateIteratorResult(true);
       EmitUnwindBeforeReturn();
@@ -2003,6 +2009,10 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
       __ jmp(&l_suspend);
       __ bind(&l_continuation);
       __ RecordGeneratorContinuation();
+      __ pop(r1);
+      // 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);
@@ -2148,6 +2158,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
       __ add(r3, r3, r2);
       __ mov(r2, Operand(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
       __ str(r2, FieldMemOperand(r1, JSGeneratorObject::kContinuationOffset));
+      __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
       __ Jump(r3);
     }
     __ bind(&slow_resume);
@@ -2162,6 +2173,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
   __ push(r2);
   __ b(&push_operand_holes);
   __ bind(&call_resume);
+  __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
   DCHECK(!result_register().is(r1));
   __ Push(r1, result_register());
   __ Push(Smi::FromInt(resume_mode));