[interpreter] Inline Star on dispatch for some bytecodes

src/interpreter/interpreter-assembler.cc

 // Copyright 2015 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.
 
 #include "src/interpreter/interpreter-assembler.h"
 
 #include <limits>
 #include <ostream>
 
 #include "src/code-factory.h"
@@ skipping 12 matching lines @@
 using compiler::Node;
 
 InterpreterAssembler::InterpreterAssembler(Isolate* isolate, Zone* zone,
                                            Bytecode bytecode,
                                            OperandScale operand_scale)
     : CodeStubAssembler(isolate, zone, InterpreterDispatchDescriptor(isolate),
                         Code::ComputeFlags(Code::BYTECODE_HANDLER),
                         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),
       accumulator_use_(AccumulatorUse::kNone),
       made_call_(false),
       disable_stack_check_across_call_(false),
       stack_pointer_before_call_(nullptr) {
   accumulator_.Bind(
       Parameter(InterpreterDispatchDescriptor::kAccumulatorParameter));
+  bytecode_offset_.Bind(
+      Parameter(InterpreterDispatchDescriptor::kBytecodeOffsetParameter));
   if (FLAG_trace_ignition) {
     TraceBytecode(Runtime::kInterpreterTraceBytecodeEntry);
   }
 }
 
 InterpreterAssembler::~InterpreterAssembler() {
   // If the following check fails the handler does not use the
   // accumulator in the way described in the bytecode definitions in
   // bytecodes.h.
   DCHECK_EQ(accumulator_use_, Bytecodes::GetAccumulatorUse(bytecode_));
@@ skipping 24 matching lines @@
 
 Node* InterpreterAssembler::GetContext() {
   return LoadRegister(Register::current_context());
 }
 
 void InterpreterAssembler::SetContext(Node* value) {
   StoreRegister(value, Register::current_context());
 }
 
 Node* InterpreterAssembler::BytecodeOffset() {
-  return Parameter(InterpreterDispatchDescriptor::kBytecodeOffsetParameter);
+  return bytecode_offset_.value();
 }
 
 Node* InterpreterAssembler::BytecodeArrayTaggedPointer() {
   if (made_call_) {
     // If we have made a call, restore bytecode array from stack frame in case
     // the debugger has swapped us to the patched debugger bytecode array.
     return LoadRegister(Register::bytecode_array());
   } else {
     return Parameter(InterpreterDispatchDescriptor::kBytecodeArrayParameter);
   }
@@ skipping 27 matching lines @@
       MachineRepresentation::kTagged, GetInterpretedFramePointer(),
       IntPtrConstant(reg.ToOperand() << kPointerSizeLog2), value);
 }
 
 Node* InterpreterAssembler::StoreRegister(Node* value, Node* reg_index) {
   return StoreNoWriteBarrier(MachineRepresentation::kTagged,
                              GetInterpretedFramePointer(),
                              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));
 }
 
 Node* InterpreterAssembler::OperandOffset(int operand_index) {
   return IntPtrConstant(
       Bytecodes::GetOperandOffset(bytecode_, operand_index, operand_scale()));
 }
 
@@ skipping 355 matching lines @@
     Goto(&ok);
   }
 
   // Update budget.
   Bind(&ok);
   StoreNoWriteBarrier(MachineRepresentation::kWord32,
                       BytecodeArrayTaggedPointer(), budget_offset,
                       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) {
   return IntPtrAdd(BytecodeOffset(), delta);
 }
 
 Node* InterpreterAssembler::Jump(Node* delta) {
   UpdateInterruptBudget(delta);
   return DispatchTo(Advance(delta));
 }
@@ skipping 10 matching lines @@
 
 void InterpreterAssembler::JumpIfWordEqual(Node* lhs, Node* rhs, Node* delta) {
   JumpConditional(WordEqual(lhs, rhs), delta);
 }
 
 void InterpreterAssembler::JumpIfWordNotEqual(Node* lhs, Node* rhs,
                                               Node* delta) {
   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);
   }
 
   Node* target_code_entry =
       Load(MachineType::Pointer(), DispatchTableRawPointer(),
            WordShl(target_bytecode, IntPtrConstant(kPointerSizeLog2)));
 
   return DispatchToBytecodeHandlerEntry(target_code_entry, new_bytecode_offset);
 }
@@ skipping 19 matching lines @@
 
 void InterpreterAssembler::DispatchWide(OperandScale operand_scale) {
   // Dispatching a wide bytecode requires treating the prefix
   // bytecode a base pointer into the dispatch table and dispatching
   // the bytecode that follows relative to this base.
   //
   //   Indices 0-255 correspond to bytecodes with operand_scale == 0
   //   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);
   }
 
   if (FLAG_trace_ignition_dispatches) {
     TraceBytecodeDispatch(next_bytecode);
   }
 
   Node* base_index;
   switch (operand_scale) {
@@ skipping 176 matching lines @@
     Goto(&loop);
   }
   Bind(&done_loop);
 
   return array;
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8