[turbofan] Lower %_DebugIsActive intrinsic.

Add support to lower the %_DebugIsActive intrinsic during
JSIntrinsicLowering instead of always going to the runtime
for this.

This addresses part of the Bluebird regression caused by
sending let and const to TurboFan and Ignition.

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2550043002
Cr-Commit-Position: refs/heads/master@{#41468}

src/compiler/access-builder.cc

@@ -22,6 +22,14 @@ FieldAccess AccessBuilder::ForExternalDoubleValue() {
   return access;
 }
 
+// static
+FieldAccess AccessBuilder::ForExternalUint8Value() {
+  FieldAccess access = {kUntaggedBase,        0,
+                        MaybeHandle<Name>(),  TypeCache::Get().kUint8,
+                        MachineType::Uint8(), kNoWriteBarrier};
+  return access;
+}
+
 // static
 FieldAccess AccessBuilder::ForMap() {
   FieldAccess access = {

src/compiler/access-builder.h

@@ -26,6 +26,9 @@ class V8_EXPORT_PRIVATE AccessBuilder final
   // Provides access to a double field identified by an external reference.
   static FieldAccess ForExternalDoubleValue();
 
+  // Provides access to an uint8 field identified by an external reference.
+  static FieldAccess ForExternalUint8Value();
+
   // ===========================================================================
   // Access to heap object fields and elements (based on tagged pointer).
 

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();

src/compiler/js-intrinsic-lowering.h

@@ -40,6 +40,7 @@ class V8_EXPORT_PRIVATE JSIntrinsicLowering final
 
  private:
   Reduction ReduceCreateIterResultObject(Node* node);
+  Reduction ReduceDebugIsActive(Node* node);
   Reduction ReduceDeoptimizeNow(Node* node);
   Reduction ReduceGeneratorClose(Node* node);
   Reduction ReduceGeneratorGetInputOrDebugPos(Node* node);