[maglev] Support TestUndetectable

Bug: v8:7700
Change-Id: Ibf21ca005754d9dba2669175a24a74f96ff871a5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3760459
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81718}

src/maglev/maglev-graph-builder.cc

@@ -641,7 +641,10 @@ void MaglevGraphBuilder::VisitTestReferenceEqual() {
   SetAccumulator(AddNewNode<TaggedEqual>({lhs, rhs}));
 }
 
-MAGLEV_UNIMPLEMENTED_BYTECODE(TestUndetectable)
+void MaglevGraphBuilder::VisitTestUndetectable() {
+  ValueNode* value = GetAccumulatorTagged();
+  SetAccumulator(AddNewNode<TestUndetectable>({value}));
+}
 
 void MaglevGraphBuilder::VisitTestNull() {
   ValueNode* value = GetAccumulatorTagged();

src/maglev/maglev-graph-verifier.h

@@ -105,6 +105,7 @@ class MaglevGraphVerifier {
       case Opcode::kCreateFunctionContext:
       case Opcode::kCreateClosure:
       case Opcode::kFastCreateClosure:
+      case Opcode::kTestUndetectable:
       case Opcode::kReturn:
         DCHECK_EQ(node->input_count(), 1);
         CheckValueInputIs(node, 0, ValueRepresentation::kTagged);

src/maglev/maglev-ir.cc

@@ -1725,6 +1725,30 @@ void TaggedEqual::GenerateCode(MaglevCodeGenState* code_gen_state,
   __ bind(&done);
 }
 
+void TestUndetectable::AllocateVreg(MaglevVregAllocationState* vreg_state) {
+  UseRegister(value());
+  set_temporaries_needed(1);
+  DefineAsRegister(vreg_state, this);
+}
+void TestUndetectable::GenerateCode(MaglevCodeGenState* code_gen_state,
+                                    const ProcessingState& state) {
+  Register object = ToRegister(value());
+  Register return_value = ToRegister(result());
+  RegList temps = temporaries();
+  Register tmp = temps.PopFirst();
+  Label done;
+  __ LoadRoot(return_value, RootIndex::kFalseValue);
+  // If the object is an Smi, return false.
+  __ JumpIfSmi(object, &done);
+  // If it is a HeapObject, load the map and check for the undetectable bit.
+  __ LoadMap(tmp, object);
+  __ movl(tmp, FieldOperand(tmp, Map::kBitFieldOffset));
+  __ testl(tmp, Immediate(Map::Bits1::IsUndetectableBit::kMask));
+  __ j(zero, &done);
+  __ LoadRoot(return_value, RootIndex::kTrueValue);
+  __ bind(&done);
+}
+
 void ChangeInt32ToFloat64::AllocateVreg(MaglevVregAllocationState* vreg_state) {
   UseRegister(input());
   DefineAsRegister(vreg_state, this);

src/maglev/maglev-ir.h

@@ -145,6 +145,7 @@ class CompactInterpreterFrameState;
   V(Float64Box)                   \
   V(CheckedFloat64Unbox)          \
   V(TaggedEqual)                  \
+  V(TestUndetectable)             \
   CONSTANT_VALUE_NODE_LIST(V)     \
   INT32_OPERATIONS_NODE_LIST(V)   \
   FLOAT64_OPERATIONS_NODE_LIST(V) \
@@ -1554,6 +1555,19 @@ class TaggedEqual : public FixedInputValueNodeT<2, TaggedEqual> {
   void PrintParams(std::ostream&, MaglevGraphLabeller*) const {}
 };
 
+class TestUndetectable : public FixedInputValueNodeT<1, TestUndetectable> {
+  using Base = FixedInputValueNodeT<1, TestUndetectable>;
+
+ public:
+  explicit TestUndetectable(uint64_t bitfield) : Base(bitfield) {}
+
+  Input& value() { return Node::input(0); }
+
+  void AllocateVreg(MaglevVregAllocationState*);
+  void GenerateCode(MaglevCodeGenState*, const ProcessingState&);
+  void PrintParams(std::ostream&, MaglevGraphLabeller*) const {}
+};
+
 class InitialValue : public FixedInputValueNodeT<0, InitialValue> {
   using Base = FixedInputValueNodeT<0, InitialValue>;