[generators] 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 add71bc879454a9baad036d0a656f972b7f64dce..bf5aceec4dbb6f2e4e72212bb182b02aa8618841 100644
--- a/src/full-codegen/ia32/full-codegen-ia32.cc
+++ b/src/full-codegen/ia32/full-codegen-ia32.cc
@@ -1846,8 +1846,17 @@ 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());
@@ -2060,6 +2069,7 @@ 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);
   }
@@ -2073,6 +2083,7 @@ 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));