[compiler] Remove obsolete JSYield operator.

R=bmeurer@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/1981323002
Cr-Commit-Position: refs/heads/master@{#36312}

src/compiler/ast-graph-builder.cc

@@ -2251,7 +2251,7 @@ void AstGraphBuilder::VisitAssignment(Assignment* expr) {
 
 
 void AstGraphBuilder::VisitYield(Yield* expr) {
-  // TODO(turbofan): Implement yield here.
+  // Generator functions are supported only by going through Ignition first.
   SetStackOverflow();
   ast_context()->ProduceValue(jsgraph()->UndefinedConstant());
 }

src/compiler/js-generic-lowering.cc

@@ -680,9 +680,6 @@ void JSGenericLowering::LowerJSStoreMessage(Node* node) {
 }
 
 
-void JSGenericLowering::LowerJSYield(Node* node) { UNIMPLEMENTED(); }
-
-
 void JSGenericLowering::LowerJSStackCheck(Node* node) {
   Node* effect = NodeProperties::GetEffectInput(node);
   Node* control = NodeProperties::GetControlInput(node);

src/compiler/js-operator.cc

@@ -391,7 +391,6 @@ const CreateLiteralParameters& CreateLiteralParametersOf(const Operator* op) {
   V(ToNumber, Operator::kNoProperties, 1, 1)               \
   V(ToObject, Operator::kFoldable, 1, 1)                   \
   V(ToString, Operator::kNoProperties, 1, 1)               \
-  V(Yield, Operator::kNoProperties, 1, 1)                  \
   V(Create, Operator::kEliminatable, 2, 1)                 \
   V(CreateIterResultObject, Operator::kEliminatable, 2, 1) \
   V(HasProperty, Operator::kNoProperties, 2, 1)            \

src/compiler/js-operator.h

@@ -410,7 +410,6 @@ class JSOperatorBuilder final : public ZoneObject {
   const Operator* ToNumber();
   const Operator* ToObject();
   const Operator* ToString();
-  const Operator* Yield();
 
   const Operator* Create();
   const Operator* CreateArguments(CreateArgumentsType type);

src/compiler/opcodes.h

@@ -151,7 +151,6 @@
   V(JSForInStep)            \
   V(JSLoadMessage)          \
   V(JSStoreMessage)         \
-  V(JSYield)                \
   V(JSStackCheck)
 
 #define JS_OP_LIST(V)     \

src/compiler/typer.cc

@@ -1528,9 +1528,6 @@ Type* Typer::Visitor::TypeJSCreateScriptContext(Node* node) {
 // JS other operators.
 
 
-Type* Typer::Visitor::TypeJSYield(Node* node) { return Type::Any(); }
-
-
 Type* Typer::Visitor::TypeJSCallConstruct(Node* node) {
   return Type::Receiver();
 }

src/compiler/verifier.cc

@@ -605,7 +605,6 @@ void Verifier::Visitor::Check(Node* node) {
       break;
     case IrOpcode::kJSCallFunction:
     case IrOpcode::kJSCallRuntime:
-    case IrOpcode::kJSYield:
       // Type can be anything.
       CheckUpperIs(node, Type::Any());
       break;

test/unittests/compiler/js-operator-unittest.cc

@@ -52,7 +52,6 @@ const SharedOperator kSharedOperators[] = {
     SHARED(ToString, Operator::kNoProperties, 1, 1, 1, 1, 1, 1, 2),
     SHARED(ToName, Operator::kNoProperties, 1, 1, 1, 1, 1, 1, 2),
     SHARED(ToObject, Operator::kFoldable, 1, 1, 1, 1, 1, 1, 2),
-    SHARED(Yield, Operator::kNoProperties, 1, 0, 1, 1, 1, 1, 2),
     SHARED(Create, Operator::kEliminatable, 2, 1, 1, 0, 1, 1, 0),
     SHARED(HasProperty, Operator::kNoProperties, 2, 1, 1, 1, 1, 1, 2),
     SHARED(TypeOf, Operator::kPure, 1, 0, 0, 0, 1, 0, 0),