[interpreter] Inline Star on dispatch for some bytecodes

src/interpreter/interpreter-assembler.cc

Index: src/interpreter/interpreter-assembler.cc
diff --git a/src/interpreter/interpreter-assembler.cc b/src/interpreter/interpreter-assembler.cc
index ee5f8be27981f19b63ddf8eb3029729cb147a7fa..9829bec3eef710cd6432aff34889a7fb0f61273e 100644
--- a/src/interpreter/interpreter-assembler.cc
+++ b/src/interpreter/interpreter-assembler.cc
@@ -30,6 +30,7 @@ InterpreterAssembler::InterpreterAssembler(Isolate* isolate, Zone* zone,
                         Bytecodes::ToString(bytecode),
                         Bytecodes::ReturnCount(bytecode)),
       bytecode_(bytecode),
+      bytecode_offset_(this, MachineType::PointerRepresentation()),
       operand_scale_(operand_scale),
       interpreted_frame_pointer_(this, MachineType::PointerRepresentation()),
       accumulator_(this, MachineRepresentation::kTagged),
@@ -39,6 +40,8 @@ InterpreterAssembler::InterpreterAssembler(Isolate* isolate, Zone* zone,
       stack_pointer_before_call_(nullptr) {
   accumulator_.Bind(
       Parameter(InterpreterDispatchDescriptor::kAccumulatorParameter));
+  bytecode_offset_.Bind(
+      Parameter(InterpreterDispatchDescriptor::kBytecodeOffsetParameter));
   if (FLAG_trace_ignition) {
     TraceBytecode(Runtime::kInterpreterTraceBytecodeEntry);
   }
@@ -83,7 +86,7 @@ void InterpreterAssembler::SetContext(Node* value) {
 }
 
 Node* InterpreterAssembler::BytecodeOffset() {
-  return Parameter(InterpreterDispatchDescriptor::kBytecodeOffsetParameter);
+  return bytecode_offset_.value();
 }
 
 Node* InterpreterAssembler::BytecodeArrayTaggedPointer() {
@@ -506,8 +509,12 @@ void InterpreterAssembler::UpdateInterruptBudget(Node* weight) {
                       new_budget.value());
 }
 
+Node* InterpreterAssembler::Advance() {
+  return Advance(Bytecodes::Size(bytecode_, operand_scale_));
+}
+
 Node* InterpreterAssembler::Advance(int delta) {
-  return IntPtrAdd(BytecodeOffset(), IntPtrConstant(delta));
+  return Advance(IntPtrConstant(delta));
 }
 
 Node* InterpreterAssembler::Advance(Node* delta) {
@@ -516,6 +523,9 @@ Node* InterpreterAssembler::Advance(Node* delta) {
 
 Node* InterpreterAssembler::Jump(Node* delta) {
   UpdateInterruptBudget(delta);
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
+  }
   return DispatchTo(Advance(delta));
 }
 
@@ -538,17 +548,80 @@ void InterpreterAssembler::JumpIfWordNotEqual(Node* lhs, Node* rhs,
   JumpConditional(WordNotEqual(lhs, rhs), delta);
 }
 
+Node* InterpreterAssembler::LoadBytecode(compiler::Node* bytecode_offset) {
+  return Load(MachineType::Uint8(), BytecodeArrayTaggedPointer(),
+              bytecode_offset);
+}
+
 Node* InterpreterAssembler::Dispatch() {
-  return DispatchTo(Advance(Bytecodes::Size(bytecode_, operand_scale_)));
+  Node* target_offset = Advance();
+  Node* target_bytecode = LoadBytecode(target_offset);
+  Variable var_offset(this, MachineType::PointerRepresentation());
+  Variable var_bytecode(this, MachineRepresentation::kWord8);
+  var_offset.Bind(target_offset);
+  var_bytecode.Bind(target_bytecode);
+
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
+  }
+
+  if (Bytecodes::IsStarLookahead(bytecode_, operand_scale_)) {
+    StarDispatchLookahead(var_bytecode, var_offset);
+  }
+  return DispatchToBytecode(var_bytecode.value(), var_offset.value());
+}
+
+void InterpreterAssembler::StarDispatchLookahead(Variable& target_bytecode,
+                                                 Variable& target_offset) {
+  Label store(this), done(this);
+
+  Node* star_bytecode = Int32Constant(static_cast<int>(Bytecode::kStar));
+  Node* is_star = WordEqual(target_bytecode.value(), star_bytecode);
+  BranchIf(is_star, &store, &done);
+  Bind(&store);
+  {
+    InlineStar(target_offset);
+    target_bytecode.Bind(LoadBytecode(target_offset.value()));
+    Goto(&done);
+  }
+  Bind(&done);
+}
+
+void InterpreterAssembler::InlineStar(Variable& target_offset) {
+  Bytecode previous_bytecode = bytecode_;
+  Variable previous_offset = bytecode_offset_;
+  AccumulatorUse previous_acc_use = accumulator_use_;
+  bytecode_ = Bytecode::kStar;
+  bytecode_offset_ = target_offset;
+  accumulator_use_ = AccumulatorUse::kNone;
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeEntry);
+  }
+
+  StoreRegister(GetAccumulator(), BytecodeOperandReg(0));
+
+  DCHECK_EQ(accumulator_use_, Bytecodes::GetAccumulatorUse(bytecode_));
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
+  }
+  Node* next_bytecode_offset = Advance();
+  target_offset.Bind(next_bytecode_offset);
+
+  bytecode_ = previous_bytecode;
+  bytecode_offset_ = previous_offset;
+  accumulator_use_ = previous_acc_use;
 }
 
 Node* InterpreterAssembler::DispatchTo(Node* new_bytecode_offset) {
-  Node* target_bytecode = Load(
-      MachineType::Uint8(), BytecodeArrayTaggedPointer(), new_bytecode_offset);
+  Node* target_bytecode = LoadBytecode(new_bytecode_offset);
+  return DispatchToBytecode(target_bytecode, new_bytecode_offset);
+}
+
+Node* InterpreterAssembler::DispatchToBytecode(Node* target_bytecode,
+                                               Node* new_bytecode_offset) {
   if (kPointerSize == 8) {
     target_bytecode = ChangeUint32ToUint64(target_bytecode);
   }
-
   if (FLAG_trace_ignition_dispatches) {
     TraceBytecodeDispatch(target_bytecode);
   }
@@ -564,15 +637,14 @@ Node* InterpreterAssembler::DispatchToBytecodeHandler(Node* handler,
                                                       Node* bytecode_offset) {
   Node* handler_entry =
       IntPtrAdd(handler, IntPtrConstant(Code::kHeaderSize - kHeapObjectTag));
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
+  }
   return DispatchToBytecodeHandlerEntry(handler_entry, bytecode_offset);
 }
 
 Node* InterpreterAssembler::DispatchToBytecodeHandlerEntry(
     Node* handler_entry, Node* bytecode_offset) {
-  if (FLAG_trace_ignition) {
-    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
-  }
-
   InterpreterDispatchDescriptor descriptor(isolate());
   Node* args[] = {GetAccumulatorUnchecked(), bytecode_offset,
                   BytecodeArrayTaggedPointer(), DispatchTableRawPointer()};
@@ -588,8 +660,7 @@ void InterpreterAssembler::DispatchWide(OperandScale operand_scale) {
   //   Indices 256-511 correspond to bytecodes with operand_scale == 1
   //   Indices 512-767 correspond to bytecodes with operand_scale == 2
   Node* next_bytecode_offset = Advance(1);
-  Node* next_bytecode = Load(MachineType::Uint8(), BytecodeArrayTaggedPointer(),
-                             next_bytecode_offset);
+  Node* next_bytecode = LoadBytecode(next_bytecode_offset);
   if (kPointerSize == 8) {
     next_bytecode = ChangeUint32ToUint64(next_bytecode);
   }