Implement [Generator].prototype.return.

src/full-codegen/mips/full-codegen-mips.cc

Index: src/full-codegen/mips/full-codegen-mips.cc
diff --git a/src/full-codegen/mips/full-codegen-mips.cc b/src/full-codegen/mips/full-codegen-mips.cc
index c378f96838202cc4c0136c777370a8a5fd431cc7..1dafb091eb76cc591e10bad3f2cd5e8e0bbb8ce9 100644
--- a/src/full-codegen/mips/full-codegen-mips.cc
+++ b/src/full-codegen/mips/full-codegen-mips.cc
@@ -1926,8 +1926,17 @@ 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(a1);
+      __ Branch(&resume, ne, a1,
+                Operand(Smi::FromInt(JSGeneratorObject::RETURN)));
+      __ push(result_register());
+      EmitCreateIteratorResult(true);
+      EmitUnwindBeforeReturn();
+      EmitReturnSequence();
 
       __ bind(&suspend);
       VisitForAccumulatorValue(expr->generator_object());
@@ -1954,9 +1963,6 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
 
     case Yield::kFinal: {
       VisitForAccumulatorValue(expr->generator_object());
-      __ li(a1, Operand(Smi::FromInt(JSGeneratorObject::kGeneratorClosed)));
-      __ sw(a1, FieldMemOperand(result_register(),
-                                JSGeneratorObject::kContinuationOffset));
       // Pop value from top-of-stack slot, box result into result register.
       EmitCreateIteratorResult(true);
       EmitUnwindBeforeReturn();
@@ -2001,6 +2007,10 @@ void FullCodeGenerator::VisitYield(Yield* expr) {
       __ jmp(&l_suspend);
       __ bind(&l_continuation);
       __ RecordGeneratorContinuation();
+      __ pop(a1);
+      // 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.
       __ mov(a0, v0);
       __ jmp(&l_resume);
 
@@ -2140,6 +2150,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
     __ Addu(a3, a3, Operand(a2));
     __ li(a2, Operand(Smi::FromInt(JSGeneratorObject::kGeneratorExecuting)));
     __ sw(a2, FieldMemOperand(a1, JSGeneratorObject::kContinuationOffset));
+    __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
     __ Jump(a3);
     __ bind(&slow_resume);
   }
@@ -2153,6 +2164,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
   __ push(a2);
   __ Branch(&push_operand_holes);
   __ bind(&call_resume);
+  __ Push(Smi::FromInt(resume_mode));  // Consumed in continuation.
   DCHECK(!result_register().is(a1));
   __ Push(a1, result_register());
   __ Push(Smi::FromInt(resume_mode));