[interpreter] Deprecate DeleteLookupSlot bytecode.

This replaces the bytecode in question with a runtime call within the
bytecode stream. The tradeoff is to safe one bytecode opcode for more
expensive encoding of lookup slot deletion.

R=rmcilroy@chromium.org

Review URL: https://codereview.chromium.org/1690913002

Cr-Commit-Position: refs/heads/master@{#33907}

src/compiler/bytecode-graph-builder.cc

@@ -1305,14 +1305,6 @@ void BytecodeGraphBuilder::VisitDeletePropertySloppy() {
   BuildDelete(LanguageMode::SLOPPY);
 }
 
-void BytecodeGraphBuilder::VisitDeleteLookupSlot() {
-  FrameStateBeforeAndAfter states(this);
-  Node* name = environment()->LookupAccumulator();
-  const Operator* op = javascript()->CallRuntime(Runtime::kDeleteLookupSlot);
-  Node* result = NewNode(op, name);
-  environment()->BindAccumulator(result, &states);
-}
-
 void BytecodeGraphBuilder::BuildCompareOp(const Operator* js_op) {
   FrameStateBeforeAndAfter states(this);
   Node* left =

src/interpreter/bytecode-array-builder.cc

@@ -1204,12 +1204,6 @@ BytecodeArrayBuilder& BytecodeArrayBuilder::Delete(Register object,
 }
 
 
-BytecodeArrayBuilder& BytecodeArrayBuilder::DeleteLookupSlot() {
-  Output(Bytecode::kDeleteLookupSlot);
-  return *this;
-}
-
-
 size_t BytecodeArrayBuilder::GetConstantPoolEntry(Handle<Object> object) {
   return constant_array_builder()->Insert(object);
 }

src/interpreter/bytecode-array-builder.h

@@ -207,7 +207,6 @@ class BytecodeArrayBuilder final : public ZoneObject, private RegisterMover {
   // Deletes property from an object. This expects that accumulator contains
   // the key to be deleted and the register contains a reference to the object.
   BytecodeArrayBuilder& Delete(Register object, LanguageMode language_mode);
-  BytecodeArrayBuilder& DeleteLookupSlot();
 
   // Tests.
   BytecodeArrayBuilder& CompareOperation(Token::Value op, Register reg,

src/interpreter/bytecode-generator.cc

@@ -2423,7 +2423,11 @@ void BytecodeGenerator::VisitDelete(UnaryOperation* expr) {
         break;
       }
       case VariableLocation::LOOKUP: {
-        builder()->LoadLiteral(variable->name()).DeleteLookupSlot();
+        Register name_reg = register_allocator()->NewRegister();
+        builder()
+            ->LoadLiteral(variable->name())
+            .StoreAccumulatorInRegister(name_reg)
+            .CallRuntime(Runtime::kDeleteLookupSlot, name_reg, 1);
         break;
       }
       default:

src/interpreter/bytecodes.h

@@ -162,7 +162,6 @@ namespace interpreter {
   V(TypeOf, OperandType::kNone)                                                \
   V(DeletePropertyStrict, OperandType::kReg8)                                  \
   V(DeletePropertySloppy, OperandType::kReg8)                                  \
-  V(DeleteLookupSlot, OperandType::kNone)                                      \
                                                                                \
   /* Call operations */                                                        \
   V(Call, OperandType::kReg8, OperandType::kReg8, OperandType::kRegCount8,     \

src/interpreter/interpreter.cc

@@ -1020,18 +1020,6 @@ void Interpreter::DoDeletePropertySloppy(InterpreterAssembler* assembler) {
 }
 
 
-// DeleteLookupSlot
-//
-// Delete the variable with the name specified in the accumulator by dynamically
-// looking it up.
-void Interpreter::DoDeleteLookupSlot(InterpreterAssembler* assembler) {
-  Node* name = __ GetAccumulator();
-  Node* context = __ GetContext();
-  Node* result = __ CallRuntime(Runtime::kDeleteLookupSlot, context, name);
-  __ SetAccumulator(result);
-  __ Dispatch();
-}
-
 void Interpreter::DoJSCall(InterpreterAssembler* assembler) {
   Node* function_reg = __ BytecodeOperandReg(0);
   Node* function = __ LoadRegister(function_reg);

test/cctest/interpreter/test-bytecode-generator.cc

@@ -8028,15 +8028,16 @@ TEST(DeleteLookupSlotInEval) {
   // clang-format off
   ExpectedSnippet<const char*> snippets[] = {
       {"delete x;",
-       0 * kPointerSize,
+       1 * kPointerSize,
        1,
-       6,
+       12,
        {
-           B(StackCheck),          //
-           B(LdaConstant), U8(0),  //
-           B(DeleteLookupSlot),    //
-           B(LdaUndefined),        //
-           B(Return)               //
+           B(StackCheck),                                                 //
+           B(LdaConstant), U8(0),                                         //
+           B(Star), R(0),                                                 //
+           B(CallRuntime), U16(Runtime::kDeleteLookupSlot), R(0), U8(1),  //
+           B(LdaUndefined),                                               //
+           B(Return)                                                      //
        },
        1,
        {"x"}},
@@ -8051,14 +8052,15 @@ TEST(DeleteLookupSlotInEval) {
        },
        0},
       {"return delete z;",
-       0 * kPointerSize,
+       1 * kPointerSize,
        1,
-       5,
+       11,
        {
-           B(StackCheck),          //
-           B(LdaConstant), U8(0),  //
-           B(DeleteLookupSlot),    //
-           B(Return)               //
+           B(StackCheck),                                                 //
+           B(LdaConstant), U8(0),                                         //
+           B(Star), R(0),                                                 //
+           B(CallRuntime), U16(Runtime::kDeleteLookupSlot), R(0), U8(1),  //
+           B(Return)                                                      //
        },
        1,
        {"z"}},

test/unittests/interpreter/bytecode-array-builder-unittest.cc

@@ -133,9 +133,7 @@ TEST_F(BytecodeArrayBuilderTest, AllBytecodesGenerated) {
   builder.LogicalNot().TypeOf();
 
   // Emit delete
-  builder.Delete(reg, LanguageMode::SLOPPY)
-      .Delete(reg, LanguageMode::STRICT)
-      .DeleteLookupSlot();
+  builder.Delete(reg, LanguageMode::SLOPPY).Delete(reg, LanguageMode::STRICT);
 
   // Emit new.
   builder.New(reg, reg, 0);

test/unittests/interpreter/bytecodes-unittest.cc

@@ -95,7 +95,6 @@ TEST(Bytecodes, HasAnyRegisterOperands) {
       2);
   CHECK_EQ(Bytecodes::NumberOfRegisterOperands(Bytecode::kDeletePropertyStrict),
            1);
-  CHECK_EQ(Bytecodes::NumberOfRegisterOperands(Bytecode::kDeleteLookupSlot), 0);
   CHECK_EQ(Bytecodes::NumberOfRegisterOperands(Bytecode::kForInPrepare), 1);
   CHECK_EQ(Bytecodes::NumberOfRegisterOperands(Bytecode::kForInPrepareWide), 1);
   CHECK_EQ(Bytecodes::NumberOfRegisterOperands(Bytecode::kInc), 0);