[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..c75a203d02d9ce2838afaa18dc4bf3671bcb5f0a 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, MachineRepresentation::kTagged),
       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() {
@@ -131,6 +134,13 @@ Node* InterpreterAssembler::StoreRegister(Node* value, Node* reg_index) {
                              RegisterFrameOffset(reg_index), value);
 }
 
+Node* InterpreterAssembler::StoreAccumulatorToRegister() {
+  DCHECK_EQ(bytecode_, Bytecode::kStar);
+  Node* reg_index = BytecodeOperandReg(0);
+  Node* accumulator = GetAccumulator();
+  return StoreRegister(accumulator, reg_index);
+}
+
 Node* InterpreterAssembler::NextRegister(Node* reg_index) {
   // Register indexes are negative, so the next index is minus one.
   return IntPtrAdd(reg_index, IntPtrConstant(-1));
@@ -506,8 +516,12 @@ 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) {
@@ -538,17 +552,65 @@ 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, MachineRepresentation::kTagged);
+  Variable var_bytecode(this, MachineRepresentation::kWord32);
+  var_offset.Bind(target_offset);
+  var_bytecode.Bind(target_bytecode);
+
+  if (Bytecodes::IsStarLookahead(bytecode_, operand_scale_)) {
+    InlineDispatchToStar(var_bytecode, var_offset);
+  }
+  return DispatchToLoaded(var_bytecode.value(), var_offset.value());
+}
+
+void InterpreterAssembler::InlineDispatchToStar(Variable& target_bytecode,
+                                                Variable& target_offset) {
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeExit);
+  }
+  DCHECK_EQ(accumulator_use_, Bytecodes::GetAccumulatorUse(bytecode_));
+  bytecode_ = Bytecode::kStar;
+  bytecode_offset_.Bind(target_offset.value());
+  accumulator_use_ = AccumulatorUse::kNone;
+  if (FLAG_trace_ignition) {
+    TraceBytecode(Runtime::kInterpreterTraceBytecodeEntry);
+  }
+
+  Variable* merged_vars[2] = {&target_offset, &target_bytecode};
+  Label store_register(this), dispatch(this, 2, merged_vars);

[oth, 2016/07/15 15:30:51]

Naming here might be better as store and store_done. Dispatch isn't being done
here.

[klaasb, 2016/07/15 18:01:24]

Done.

+
+  Node* star_bytecode = Int32Constant(static_cast<int>(Bytecode::kStar));
+  Node* is_star = WordEqual(target_bytecode.value(), star_bytecode);
+  BranchIf(is_star, &store_register, &dispatch);
+  Bind(&store_register);
+  {
+    StoreAccumulatorToRegister();
+    Node* next_bytecode_offset = Advance();
+    target_offset.Bind(next_bytecode_offset);
+    target_bytecode.Bind(LoadBytecode(next_bytecode_offset));
+    Goto(&dispatch);
+  }
+  Bind(&dispatch);
 }
 
 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 DispatchToLoaded(target_bytecode, new_bytecode_offset);
+}
+
+Node* InterpreterAssembler::DispatchToLoaded(Node* target_bytecode,
+                                             Node* new_bytecode_offset) {
   if (kPointerSize == 8) {
     target_bytecode = ChangeUint32ToUint64(target_bytecode);
   }
-
   if (FLAG_trace_ignition_dispatches) {
     TraceBytecodeDispatch(target_bytecode);
   }
@@ -588,8 +650,7 @@ 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);
   }