[turbofan] Lower %_DebugIsActive intrinsic.

src/compiler/js-intrinsic-lowering.cc

Index: src/compiler/js-intrinsic-lowering.cc
diff --git a/src/compiler/js-intrinsic-lowering.cc b/src/compiler/js-intrinsic-lowering.cc
index 52903232d7183a37e3aa9015e4a48748af9f293c..857c0f50dba0fcef4b915ddf4d00a037024fc8b8 100644
--- a/src/compiler/js-intrinsic-lowering.cc
+++ b/src/compiler/js-intrinsic-lowering.cc
@@ -32,6 +32,8 @@ Reduction JSIntrinsicLowering::Reduce(Node* node) {
   switch (f->function_id) {
     case Runtime::kInlineCreateIterResultObject:
       return ReduceCreateIterResultObject(node);
+    case Runtime::kInlineDebugIsActive:
+      return ReduceDebugIsActive(node);
     case Runtime::kInlineDeoptimizeNow:
       return ReduceDeoptimizeNow(node);
     case Runtime::kInlineGeneratorClose:
@@ -90,6 +92,15 @@ Reduction JSIntrinsicLowering::ReduceCreateIterResultObject(Node* node) {
                 context, effect);
 }
 
+Reduction JSIntrinsicLowering::ReduceDebugIsActive(Node* node) {
+  Node* const value = jsgraph()->ExternalConstant(
+      ExternalReference::debug_is_active_address(isolate()));
+  Node* const effect = NodeProperties::GetEffectInput(node);
+  Node* const control = NodeProperties::GetControlInput(node);
+  Operator const* const op =
+      simplified()->LoadField(AccessBuilder::ForExternalUint8Value());
+  return Change(node, op, value, effect, control);
+}
 
 Reduction JSIntrinsicLowering::ReduceDeoptimizeNow(Node* node) {
   if (mode() != kDeoptimizationEnabled) return NoChange();