[Interpreter] Remove LdaConstant+ToName peephole optimization.

This optimization required access to the heap which we can't do off-thread.
There doesn't seem to be a regression without this optmization in anycase,
so just rip it out.

BUG=v8:5203

Review-Url: https://codereview.chromium.org/2238853002
Cr-Commit-Position: refs/heads/master@{#38585}

src/interpreter/bytecode-array-builder.cc

@@ -43,8 +43,7 @@ BytecodeArrayBuilder::BytecodeArrayBuilder(
   }
 
   if (FLAG_ignition_peephole) {
-    pipeline_ = new (zone)
-        BytecodePeepholeOptimizer(&constant_array_builder_, pipeline_);
+    pipeline_ = new (zone) BytecodePeepholeOptimizer(pipeline_);
   }
 
   if (FLAG_ignition_reo) {

src/interpreter/bytecode-peephole-optimizer.cc

@@ -4,7 +4,6 @@
 
 #include "src/interpreter/bytecode-peephole-optimizer.h"
 
-#include "src/interpreter/constant-array-builder.h"
 #include "src/objects-inl.h"
 #include "src/objects.h"
 
@@ -13,9 +12,8 @@ namespace internal {
 namespace interpreter {
 
 BytecodePeepholeOptimizer::BytecodePeepholeOptimizer(
-    ConstantArrayBuilder* constant_array_builder,
     BytecodePipelineStage* next_stage)
-    : constant_array_builder_(constant_array_builder), next_stage_(next_stage) {
+    : next_stage_(next_stage) {
   InvalidateLast();
 }
 
@@ -83,14 +81,6 @@ void BytecodePeepholeOptimizer::SetLast(const BytecodeNode* const node) {
   last_.Clone(node);
 }
 
-Handle<Object> BytecodePeepholeOptimizer::GetConstantForIndexOperand(
-    const BytecodeNode* const node, int index) const {
-  DCHECK_LE(index, node->operand_count());
-  DCHECK_EQ(Bytecodes::GetOperandType(node->bytecode(), 0), OperandType::kIdx);
-  uint32_t index_operand = node->operand(0);
-  return constant_array_builder_->At(index_operand);
-}
-
 bool BytecodePeepholeOptimizer::CanElideLastBasedOnSourcePosition(
     const BytecodeNode* const current) const {
   //
@@ -289,19 +279,6 @@ void BytecodePeepholeOptimizer::
   }
 }
 
-void BytecodePeepholeOptimizer::TransformToStarIfLoadingNameConstantAction(
-    BytecodeNode* const node, const PeepholeActionAndData* action_data) {
-  DCHECK_EQ(last()->bytecode(), Bytecode::kLdaConstant);
-  DCHECK(!Bytecodes::IsJump(node->bytecode()));
-
-  // TODO(5203): Remove this temporary exception.
-  AllowHandleDereference allow_deref;
-  if (GetConstantForIndexOperand(last(), 0)->IsName()) {
-    node->replace_bytecode(Bytecode::kStar);
-  }
-  DefaultAction(node);
-}
-
 void BytecodePeepholeOptimizer::DefaultJumpAction(
     BytecodeNode* const node, const PeepholeActionAndData* action_data) {
   DCHECK(LastIsValid());

src/interpreter/bytecode-peephole-optimizer.h

@@ -12,7 +12,6 @@ namespace v8 {
 namespace internal {
 namespace interpreter {
 
-class ConstantArrayBuilder;
 class BytecodePeepholeActionAndData;
 
 // An optimization stage for performing peephole optimizations on
@@ -21,8 +20,7 @@ class BytecodePeepholeActionAndData;
 class BytecodePeepholeOptimizer final : public BytecodePipelineStage,
                                         public ZoneObject {
  public:
-  BytecodePeepholeOptimizer(ConstantArrayBuilder* constant_array_builder,
-                            BytecodePipelineStage* next_stage);
+  explicit BytecodePeepholeOptimizer(BytecodePipelineStage* next_stage);
 
   // BytecodePipelineStage interface.
   void Write(BytecodeNode* node) override;
@@ -48,13 +46,9 @@ class BytecodePeepholeOptimizer final : public BytecodePipelineStage,
   bool LastIsValid() const;
   void SetLast(const BytecodeNode* const node);
 
-  Handle<Object> GetConstantForIndexOperand(const BytecodeNode* const node,
-                                            int index) const;
-
   BytecodePipelineStage* next_stage() const { return next_stage_; }
   BytecodeNode* last() { return &last_; }
 
-  ConstantArrayBuilder* constant_array_builder_;
   BytecodePipelineStage* next_stage_;
   BytecodeNode last_;
 

src/interpreter/bytecode-peephole-table.h

@@ -11,18 +11,17 @@ namespace v8 {
 namespace internal {
 namespace interpreter {
 
-#define PEEPHOLE_NON_JUMP_ACTION_LIST(V)              \
-  V(DefaultAction)                                    \
-  V(UpdateLastAction)                                 \
-  V(UpdateLastIfSourceInfoPresentAction)              \
-  V(ElideCurrentAction)                               \
-  V(ElideCurrentIfOperand0MatchesAction)              \
-  V(ElideLastAction)                                  \
-  V(ChangeBytecodeAction)                             \
-  V(TransformLdaStarToLdrLdarAction)                  \
-  V(TransformLdaSmiBinaryOpToBinaryOpWithSmiAction)   \
-  V(TransformLdaZeroBinaryOpToBinaryOpWithZeroAction) \
-  V(TransformToStarIfLoadingNameConstantAction)
+#define PEEPHOLE_NON_JUMP_ACTION_LIST(V)            \
+  V(DefaultAction)                                  \
+  V(UpdateLastAction)                               \
+  V(UpdateLastIfSourceInfoPresentAction)            \
+  V(ElideCurrentAction)                             \
+  V(ElideCurrentIfOperand0MatchesAction)            \
+  V(ElideLastAction)                                \
+  V(ChangeBytecodeAction)                           \
+  V(TransformLdaStarToLdrLdarAction)                \
+  V(TransformLdaSmiBinaryOpToBinaryOpWithSmiAction) \
+  V(TransformLdaZeroBinaryOpToBinaryOpWithZeroAction)
 
 #define PEEPHOLE_JUMP_ACTION_LIST(V) \
   V(DefaultJumpAction)               \

src/interpreter/mkpeephole.cc

@@ -108,13 +108,8 @@ PeepholeActionAndData PeepholeActionTableWriter::LookupActionAndData(
 
   // ToName bytecodes can be replaced by Star with the same output register if
   // the value in the accumulator is already a name.
-  if (current == Bytecode::kToName) {
-    if (last == Bytecode::kLdaConstant) {
-      return {PeepholeAction::kTransformToStarIfLoadingNameConstantAction,
-              Bytecode::kIllegal};
-    } else if (Bytecodes::PutsNameInAccumulator(last)) {
-      return {PeepholeAction::kChangeBytecodeAction, Bytecode::kStar};
-    }
+  if (current == Bytecode::kToName && Bytecodes::PutsNameInAccumulator(last)) {
+    return {PeepholeAction::kChangeBytecodeAction, Bytecode::kStar};
   }
 
   // Nop are placeholders for holding source position information and can be

test/cctest/interpreter/bytecode_expectations/ClassDeclarations.golden

@@ -35,7 +35,7 @@ bytecodes: [
                 B(Star), R(3),
                 B(LdrNamedProperty), R(3), U8(1), U8(1), R(4),
                 B(LdaConstant), U8(2),
-                B(Star), R(6),
+                B(ToName), R(6),
                 B(CreateClosure), U8(3), U8(2),
                 B(Star), R(7),
                 B(LdaSmi), U8(2),
@@ -88,7 +88,7 @@ bytecodes: [
                 B(Star), R(3),
                 B(LdrNamedProperty), R(3), U8(1), U8(1), R(4),
                 B(LdaConstant), U8(2),
-                B(Star), R(6),
+                B(ToName), R(6),
                 B(CreateClosure), U8(3), U8(2),
                 B(Star), R(7),
                 B(LdaSmi), U8(2),

test/cctest/interpreter/bytecode_expectations/ObjectLiterals.golden

@@ -404,7 +404,7 @@ bytecodes: [
                 B(Mov), R(1), R(2),
                 B(CallRuntime), U16(Runtime::kDefineDataPropertyInLiteral), R(2), U8(5),
                 B(LdaConstant), U8(3),
-                B(Star), R(3),
+                B(ToName), R(3),
                 B(CreateClosure), U8(4), U8(2),
                 B(Star), R(4),
                 B(LdaZero),
@@ -412,7 +412,7 @@ bytecodes: [
                 B(Mov), R(1), R(2),
                 B(CallRuntime), U16(Runtime::kDefineGetterPropertyUnchecked), R(2), U8(4),
                 B(LdaConstant), U8(3),
-                B(Star), R(3),
+                B(ToName), R(3),
                 B(CreateClosure), U8(5), U8(2),
                 B(Star), R(4),
                 B(LdaZero),

test/unittests/interpreter/bytecode-peephole-optimizer-unittest.cc

@@ -7,7 +7,6 @@
 #include "src/factory.h"
 #include "src/interpreter/bytecode-label.h"
 #include "src/interpreter/bytecode-peephole-optimizer.h"
-#include "src/interpreter/constant-array-builder.h"
 #include "src/objects-inl.h"
 #include "src/objects.h"
 #include "test/unittests/test-utils.h"
@@ -19,9 +18,7 @@ namespace interpreter {
 class BytecodePeepholeOptimizerTest : public BytecodePipelineStage,
                                       public TestWithIsolateAndZone {
  public:
-  BytecodePeepholeOptimizerTest()
-      : constant_array_builder_(isolate(), zone()),
-        peephole_optimizer_(&constant_array_builder_, this) {}
+  BytecodePeepholeOptimizerTest() : peephole_optimizer_(this) {}
   ~BytecodePeepholeOptimizerTest() override {}
 
   void Reset() {
@@ -52,13 +49,11 @@ class BytecodePeepholeOptimizerTest : public BytecodePipelineStage,
   }
 
   BytecodePeepholeOptimizer* optimizer() { return &peephole_optimizer_; }
-  ConstantArrayBuilder* constant_array() { return &constant_array_builder_; }
 
   int write_count() const { return write_count_; }
   const BytecodeNode& last_written() const { return last_written_; }
 
  private:
-  ConstantArrayBuilder constant_array_builder_;
   BytecodePeepholeOptimizer peephole_optimizer_;
 
   int write_count_ = 0;
@@ -266,38 +261,6 @@ TEST_F(BytecodePeepholeOptimizerTest, TypeOfToName) {
   CHECK_EQ(last_written().bytecode(), Bytecode::kStar);
 }
 
-TEST_F(BytecodePeepholeOptimizerTest, LdaConstantStringToName) {
-  Handle<Object> word =
-      isolate()->factory()->NewStringFromStaticChars("optimizing");
-  size_t index = constant_array()->Insert(word);
-  BytecodeNode first(Bytecode::kLdaConstant, static_cast<uint32_t>(index));
-  BytecodeNode second(Bytecode::kToName, Register(0).ToOperand());
-  optimizer()->Write(&first);
-  CHECK_EQ(write_count(), 0);
-  optimizer()->Write(&second);
-  CHECK_EQ(write_count(), 1);
-  CHECK_EQ(last_written(), first);
-  Flush();
-  CHECK_EQ(write_count(), 2);
-  CHECK_EQ(last_written(), second);
-  CHECK_EQ(last_written().bytecode(), Bytecode::kStar);
-}
-
-TEST_F(BytecodePeepholeOptimizerTest, LdaConstantNumberToName) {
-  Handle<Object> word = isolate()->factory()->NewNumber(0.380);
-  size_t index = constant_array()->Insert(word);
-  BytecodeNode first(Bytecode::kLdaConstant, static_cast<uint32_t>(index));
-  BytecodeNode second(Bytecode::kToName, Register(0).ToOperand());
-  optimizer()->Write(&first);
-  CHECK_EQ(write_count(), 0);
-  optimizer()->Write(&second);
-  CHECK_EQ(write_count(), 1);
-  CHECK_EQ(last_written(), first);
-  Flush();
-  CHECK_EQ(write_count(), 2);
-  CHECK_EQ(last_written(), second);
-}
-
 // Tests covering BytecodePeepholeOptimizer::CanElideLast().
 
 TEST_F(BytecodePeepholeOptimizerTest, LdaTrueLdaFalse) {