X87: Leaving a generator via an exception causes it to close

port 24a7ee877e1fe2ba0a52d69061946aeda7c26c10 (r25297)

original commit message:

  Leaving a generator via an exception causes it to close

BUG=
R=weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/724643002

Patch from Chunyang Dai <chunyang.dai@intel.com>.

Cr-Commit-Position: refs/heads/master@{#25316}

src/x87/full-codegen-x87.cc

@@ -2112,15 +2112,6 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
   VisitForAccumulatorValue(value);
   __ pop(ebx);
 
-  // Check generator state.
-  Label wrong_state, closed_state, done;
-  STATIC_ASSERT(JSGeneratorObject::kGeneratorExecuting < 0);
-  STATIC_ASSERT(JSGeneratorObject::kGeneratorClosed == 0);
-  __ cmp(FieldOperand(ebx, JSGeneratorObject::kContinuationOffset),
-         Immediate(Smi::FromInt(0)));
-  __ j(equal, &closed_state);
-  __ j(less, &wrong_state);
-
   // Load suspended function and context.
   __ mov(esi, FieldOperand(ebx, JSGeneratorObject::kContextOffset));
   __ mov(edi, FieldOperand(ebx, JSGeneratorObject::kFunctionOffset));
@@ -2142,7 +2133,7 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
 
   // Enter a new JavaScript frame, and initialize its slots as they were when
   // the generator was suspended.
-  Label resume_frame;
+  Label resume_frame, done;
   __ bind(&push_frame);
   __ call(&resume_frame);
   __ jmp(&done);
@@ -2189,25 +2180,6 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
   // Not reached: the runtime call returns elsewhere.
   __ Abort(kGeneratorFailedToResume);
 
-  // Reach here when generator is closed.
-  __ bind(&closed_state);
-  if (resume_mode == JSGeneratorObject::NEXT) {
-    // Return completed iterator result when generator is closed.
-    __ push(Immediate(isolate()->factory()->undefined_value()));
-    // Pop value from top-of-stack slot; box result into result register.
-    EmitCreateIteratorResult(true);
-  } else {
-    // Throw the provided value.
-    __ push(eax);
-    __ CallRuntime(Runtime::kThrow, 1);
-  }
-  __ jmp(&done);
-
-  // Throw error if we attempt to operate on a running generator.
-  __ bind(&wrong_state);
-  __ push(ebx);
-  __ CallRuntime(Runtime::kThrowGeneratorStateError, 1);
-
   __ bind(&done);
   context()->Plug(result_register());
 }