[maglev] Implement LoadNamedGeneric IR

Bug: v8:7700
Change-Id: I117f0ed7df60eff145b0ecd509ffa7debc137038
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3494239Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79315}

src/maglev/maglev-graph-builder.cc

@@ -127,8 +127,9 @@ void MaglevGraphBuilder::VisitLdaNamedProperty() {
     }
   }
 
+  ValueNode* context = GetContext();
   compiler::NameRef name = GetRefOperand<Name>(1);
-  SetAccumulator(AddNewNode<LoadNamedGeneric>({object}, name));
+  SetAccumulator(AddNewNode<LoadNamedGeneric>({context, object}, name));
   MarkPossibleSideEffect();
 }
 void MaglevGraphBuilder::VisitLdaNamedPropertyFromSuper() { UNREACHABLE(); }

src/maglev/maglev-ir.cc

@@ -590,12 +590,21 @@ void LoadField::PrintParams(std::ostream& os,
 
 void LoadNamedGeneric::AllocateVreg(MaglevVregAllocationState* vreg_state,
                                     const ProcessingState& state) {
-  UseRegister(object_input());
-  DefineAsRegister(vreg_state, this);
+  using D = LoadNoFeedbackDescriptor;
+  UseFixed(context(), kContextRegister);
+  UseFixed(object_input(), D::GetRegisterParameter(D::kReceiver));
+  DefineAsFixed(vreg_state, this, kReturnRegister0);
 }
 void LoadNamedGeneric::GenerateCode(MaglevCodeGenState* code_gen_state,
                                     const ProcessingState& state) {
-  UNREACHABLE();
+  using D = LoadNoFeedbackDescriptor;
+  const int ic_kind = static_cast<int>(FeedbackSlotKind::kLoadProperty);
+  DCHECK_EQ(ToRegister(context()), kContextRegister);
+  DCHECK_EQ(ToRegister(object_input()), D::GetRegisterParameter(D::kReceiver));
+  __ Move(D::GetRegisterParameter(D::kName), name().object());
+  __ Move(D::GetRegisterParameter(D::kICKind),
+          Immediate(Smi::FromInt(ic_kind)));
+  __ CallBuiltin(Builtin::kLoadIC_NoFeedback);
 }
 void LoadNamedGeneric::PrintParams(std::ostream& os,
                                    MaglevGraphLabeller* graph_labeller) const {

src/maglev/maglev-ir.h

@@ -881,8 +881,8 @@ class LoadGlobal : public FixedInputValueNodeT<1, LoadGlobal> {
   const compiler::NameRef name_;
 };
 
-class LoadNamedGeneric : public FixedInputValueNodeT<1, LoadNamedGeneric> {
-  using Base = FixedInputValueNodeT<1, LoadNamedGeneric>;
+class LoadNamedGeneric : public FixedInputValueNodeT<2, LoadNamedGeneric> {
+  using Base = FixedInputValueNodeT<2, LoadNamedGeneric>;
 
  public:
   explicit LoadNamedGeneric(size_t input_count, const compiler::NameRef& name)
@@ -893,7 +893,9 @@ class LoadNamedGeneric : public FixedInputValueNodeT<1, LoadNamedGeneric> {
 
   compiler::NameRef name() const { return name_; }
 
-  static constexpr int kObjectIndex = 0;
+  static constexpr int kContextIndex = 0;
+  static constexpr int kObjectIndex = 1;
+  Input& context() { return input(kContextIndex); }
   Input& object_input() { return input(kObjectIndex); }
 
   void AllocateVreg(MaglevVregAllocationState*, const ProcessingState&);

test/mjsunit/maglev/16.js

+// Copyright 2022 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Flags: --allow-natives-syntax
+
+function f(x) {
+  return x.a;
+}
+
+function Foo(a) {
+  this.a = a;
+}
+
+function Goo(a) {
+  this.a = a;
+}
+
+%PrepareFunctionForOptimization(f);
+
+var o1 = new Foo(42);
+var o2 = new Goo(4.2);
+
+assertEquals(f(o1), 42);
+assertEquals(f(o2), 4.2);
+
+%OptimizeMaglevOnNextCall(f);
+
+assertEquals(f(o1), 42);
+assertEquals(f(o2), 4.2);