Improve performance of arguments object allocation by taking...

src/codegen-ia32.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 500 matching lines @@
       break_stack_height_(0) {
 }
 
 
 // Calling conventions:
 // ebp: frame pointer
 // esp: stack pointer
 // edi: caller's parameter pointer
 // esi: callee's context
 
-
 void Ia32CodeGenerator::GenCode(FunctionLiteral* fun) {
   // Record the position for debugging purposes.
   __ RecordPosition(fun->start_position());
 
   Scope* scope = fun->scope();
   ZoneList<Statement*>* body = fun->body();
 
   // Initialize state.
   { CodeGenState state(this);
     scope_ = scope;
@@ skipping 26 matching lines @@
     // when the push has happened.
     bool arguments_object_allocated = false;
     bool arguments_object_saved = false;
 
     // Allocate arguments object.
     // The arguments object pointer needs to be saved in ecx, since we need
     // to store arguments into the context.
     if (scope->arguments() != NULL) {
       ASSERT(scope->arguments_shadow() != NULL);
       Comment cmnt(masm_, "[ allocate arguments object");
+      ArgumentsAccessStub stub(ArgumentsAccessStub::NEW_OBJECT);
+      __ lea(eax, ReceiverOperand());
       __ push(FunctionOperand());
-      __ CallRuntime(Runtime::kNewArguments, 1);
+      __ push(eax);
+      __ push(Immediate(Smi::FromInt(scope->num_parameters())));
+      __ CallStub(&stub);
       __ mov(ecx, Operand(eax));
       arguments_object_allocated = true;
     }
 
     // Allocate space for locals and initialize them.
     if (scope->num_stack_slots() > 0) {
       Comment cmnt(masm_, "[ allocate space for locals");
       __ Set(eax, Immediate(Factory::undefined_value()));
       for (int i = scope->num_stack_slots(); i-- > 0; ) __ push(eax);
     }
@@ skipping 481 matching lines @@
   case Token::BIT_AND: return "GenericBinaryOpStub_BIT_AND";
   case Token::BIT_XOR: return "GenericBinaryOpStub_BIT_XOR";
   case Token::SAR: return "GenericBinaryOpStub_SAR";
   case Token::SHL: return "GenericBinaryOpStub_SHL";
   case Token::SHR: return "GenericBinaryOpStub_SHR";
   default:         return "GenericBinaryOpStub";
   }
 }
 
 
-class ArgumentsAccessStub: public CodeStub {
- public:
-  explicit ArgumentsAccessStub(bool is_length) : is_length_(is_length) { }
-
- private:
-  bool is_length_;
-
-  Major MajorKey() { return ArgumentsAccess; }
-  int MinorKey() { return is_length_ ? 1 : 0; }
-  void Generate(MacroAssembler* masm);
-
-  const char* GetName() { return "ArgumentsAccessStub"; }
-
-#ifdef DEBUG
-  void Print() {
-    PrintF("ArgumentsAccessStub (is_length %s)\n",
-           is_length_ ? "true" : "false");
-  }
-#endif
-};
-
-
 void Ia32CodeGenerator::GenericBinaryOperation(Token::Value op,
                                                OverwriteMode overwrite_mode) {
   Comment cmnt(masm_, "[ BinaryOperation");
   Comment cmnt_token(masm_, Token::String(op));
   switch (op) {
     case Token::ADD:
     case Token::SUB:
     case Token::MUL:
     case Token::DIV:
     case Token::MOD: {
@@ skipping 2203 matching lines @@
 
 void Ia32CodeGenerator::GenerateArgumentsLength(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
 
   // Seed the result with the formal parameters count, which will be
   // used in case no arguments adaptor frame is found below the
   // current frame.
   __ Set(eax, Immediate(Smi::FromInt(scope_->num_parameters())));
 
   // Call the shared stub to get to the arguments.length.
-  ArgumentsAccessStub stub(true);
+  ArgumentsAccessStub stub(ArgumentsAccessStub::READ_LENGTH);
   __ CallStub(&stub);
   __ push(eax);
 }
 
 
 void Ia32CodeGenerator::GenerateValueOf(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   Label leave;
   Load(args->at(0));  // Load the object.
   __ mov(eax, TOS);
@@ skipping 42 matching lines @@
 
 void Ia32CodeGenerator::GenerateArgumentsAccess(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
 
   // Load the key onto the stack and set register eax to the formal
   // parameters count for the currently executing function.
   Load(args->at(0));
   __ Set(eax, Immediate(Smi::FromInt(scope_->num_parameters())));
 
   // Call the shared stub to get to arguments[key].
-  ArgumentsAccessStub stub(false);
+  ArgumentsAccessStub stub(ArgumentsAccessStub::READ_ELEMENT);
   __ CallStub(&stub);
   __ mov(TOS, eax);
 }
 
 
 void Ia32CodeGenerator::GenerateObjectEquals(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 2);
 
   // Load the two objects into registers and perform the comparison.
   Load(args->at(0));
@@ skipping 1418 matching lines @@
   __ fchs();
   __ fstp_d(FieldOperand(eax, HeapNumber::kValueOffset));
 
   __ bind(&done);
 
   __ StubReturn(1);
 }
 
 
 void ArgumentsAccessStub::Generate(MacroAssembler* masm) {
-  // Check that the key is a smi for non-length access.
+  // If we're reading an element we need to check that the key is a smi.
   Label slow;
-  if (!is_length_) {
+  if (type_ == READ_ELEMENT) {
     __ mov(ebx, Operand(esp, 1 * kPointerSize));  // skip return address
     __ test(ebx, Immediate(kSmiTagMask));
     __ j(not_zero, &slow, not_taken);
   }
 
   // Check if the calling frame is an arguments adaptor frame.
   Label adaptor;
   __ mov(edx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
   __ mov(ecx, Operand(edx, StandardFrameConstants::kContextOffset));
   __ cmp(ecx, ArgumentsAdaptorFrame::SENTINEL);
-  __ j(equal, &adaptor);
+  if (type_ == NEW_OBJECT) {
+    __ j(not_equal, &slow);
+  } else {
+    __ j(equal, &adaptor);
+  }
 
   // The displacement is used for skipping the return address on the
   // stack. It is the offset of the last parameter (if any) relative
   // to the frame pointer.
   static const int kDisplacement = 1 * kPointerSize;
   ASSERT(kSmiTagSize == 1 && kSmiTag == 0);  // shifting code depends on this
 
-  if (is_length_) {
-    // Do nothing. The length is already in register eax.
-  } else {
+  if (type_ == READ_LENGTH) {
+    // Nothing to do: The formal number of parameters has already been
+    // passed in register eax by calling function. Just return it.
+    __ ret(0);
+  } else if (type_ == READ_ELEMENT) {
     // Check index against formal parameters count limit passed in
     // through register eax. Use unsigned comparison to get negative
     // check for free.
     __ cmp(ebx, Operand(eax));
     __ j(above_equal, &slow, not_taken);
 
-    // Read the argument from the stack.
+    // Read the argument from the stack and return it.
     __ lea(edx, Operand(ebp, eax, times_2, 0));
     __ neg(ebx);
     __ mov(eax, Operand(edx, ebx, times_2, kDisplacement));
+    __ ret(0);
+  } else {
+    ASSERT(type_ == NEW_OBJECT);
+    // Do nothing here.
   }
 
-  // Return the length or the argument.
-  __ ret(0);
-
   // Arguments adaptor case: Find the length or the actual argument in
   // the calling frame.
   __ bind(&adaptor);
-  if (is_length_) {
-    // Read the arguments length from the adaptor frame.
+  if (type_ == READ_LENGTH) {
+    // Read the arguments length from the adaptor frame and return it.
     __ mov(eax, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
-  } else {
+    __ ret(0);
+  } else if (type_ == READ_ELEMENT) {
     // Check index against actual arguments limit found in the
     // arguments adaptor frame. Use unsigned comparison to get
     // negative check for free.
     __ mov(ecx, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
     __ cmp(ebx, Operand(ecx));
     __ j(above_equal, &slow, not_taken);
 
-    // Read the argument from the stack.
+    // Read the argument from the stack and return it.
     __ lea(edx, Operand(edx, ecx, times_2, 0));
     __ neg(ebx);
     __ mov(eax, Operand(edx, ebx, times_2, kDisplacement));
+    __ ret(0);
+  } else {
+    ASSERT(type_ == NEW_OBJECT);
+    // Patch the arguments.length and the parameters pointer.
+    __ mov(ecx, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
+    __ mov(Operand(esp, 1 * kPointerSize), ecx);
+    __ lea(edx, Operand(edx, ecx, times_2, kDisplacement + 1 * kPointerSize));
+    __ mov(Operand(esp, 2 * kPointerSize), edx);
+    __ bind(&slow);
+    __ TailCallRuntime(ExternalReference(Runtime::kNewArgumentsFast), 3);
   }
 
-  // Return the length or the argument.
-  __ ret(0);
-
   // Slow-case: Handle non-smi or out-of-bounds access to arguments
   // by calling the runtime system.
-  if (!is_length_) {
+  if (type_ == READ_ELEMENT) {
     __ bind(&slow);
     __ TailCallRuntime(ExternalReference(Runtime::kGetArgumentsProperty), 1);
   }
 }
 
 
 void CompareStub::Generate(MacroAssembler* masm) {
   Label call_builtin, done;
   // Save the return address (and get it off the stack).
   __ pop(ecx);
@@ skipping 448 matching lines @@
                                      bool is_eval) {
   Handle<Code> code = Ia32CodeGenerator::MakeCode(fun, script, is_eval);
   if (!code.is_null()) {
     Counters::total_compiled_code_size.Increment(code->instruction_size());
   }
   return code;
 }
 
 
 } }  // namespace v8::internal