Inline %_ArgumentsLength.

This makes usage of cmov unnecessary.

Review URL: http://codereview.chromium.org/1533004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4323 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/codegen-arm.cc

@@ -3587,13 +3587,22 @@ void CodeGenerator::GenerateArgumentsLength(ZoneList<Expression*>* args) {
   VirtualFrame::SpilledScope spilled_scope;
   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.
+  Label exit;
+
+  // Get the number of formal parameters.
   __ mov(r0, Operand(Smi::FromInt(scope()->num_parameters())));
 
-  // Call the shared stub to get to the arguments.length.
-  ArgumentsAccessStub stub(ArgumentsAccessStub::READ_LENGTH);
-  frame_->CallStub(&stub, 0);
+  // Check if the calling frame is an arguments adaptor frame.
+  __ ldr(r2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  __ ldr(r3, MemOperand(r2, StandardFrameConstants::kContextOffset));
+  __ cmp(r3, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
+  __ b(ne, &exit);
+
+  // Arguments adaptor case: Read the arguments length from the
+  // adaptor frame.
+  __ ldr(r0, MemOperand(r2, ArgumentsAdaptorFrameConstants::kLengthOffset));
+
+  __ bind(&exit);
   frame_->EmitPush(r0);
 }
 
@@ -6791,26 +6800,6 @@ void InstanceofStub::Generate(MacroAssembler* masm) {
 }
 
 
-void ArgumentsAccessStub::GenerateReadLength(MacroAssembler* masm) {
-  // Check if the calling frame is an arguments adaptor frame.
-  Label adaptor;
-  __ ldr(r2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
-  __ ldr(r3, MemOperand(r2, StandardFrameConstants::kContextOffset));
-  __ cmp(r3, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
-  __ b(eq, &adaptor);
-
-  // Nothing to do: The formal number of parameters has already been
-  // passed in register r0 by calling function. Just return it.
-  __ Jump(lr);
-
-  // Arguments adaptor case: Read the arguments length from the
-  // adaptor frame and return it.
-  __ bind(&adaptor);
-  __ ldr(r0, MemOperand(r2, ArgumentsAdaptorFrameConstants::kLengthOffset));
-  __ Jump(lr);
-}
-
-
 void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
   // The displacement is the offset of the last parameter (if any)
   // relative to the frame pointer.

src/codegen.cc

@@ -454,7 +454,6 @@ const char* GenericUnaryOpStub::GetName() {
 
 void ArgumentsAccessStub::Generate(MacroAssembler* masm) {
   switch (type_) {
-    case READ_LENGTH: GenerateReadLength(masm); break;
     case READ_ELEMENT: GenerateReadElement(masm); break;
     case NEW_OBJECT: GenerateNewObject(masm); break;
   }

src/codegen.h

@@ -498,7 +498,6 @@ class JSConstructEntryStub : public JSEntryStub {
 class ArgumentsAccessStub: public CodeStub {
  public:
   enum Type {
-    READ_LENGTH,
     READ_ELEMENT,
     NEW_OBJECT
   };
@@ -512,7 +511,6 @@ class ArgumentsAccessStub: public CodeStub {
   int MinorKey() { return type_; }
 
   void Generate(MacroAssembler* masm);
-  void GenerateReadLength(MacroAssembler* masm);
   void GenerateReadElement(MacroAssembler* masm);
   void GenerateNewObject(MacroAssembler* masm);
 

src/ia32/codegen-ia32.cc

@@ -6228,12 +6228,30 @@ void CodeGenerator::GenerateIsConstructCall(ZoneList<Expression*>* args) {
 
 void CodeGenerator::GenerateArgumentsLength(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
-  // ArgumentsAccessStub takes the parameter count as an input argument
-  // in register eax.  Create a constant result for it.
-  Result count(Handle<Smi>(Smi::FromInt(scope()->num_parameters())));
-  // Call the shared stub to get to the arguments.length.
-  ArgumentsAccessStub stub(ArgumentsAccessStub::READ_LENGTH);
-  Result result = frame_->CallStub(&stub, &count);
+
+  Result fp = allocator_->Allocate();
+  Result result = allocator_->Allocate();
+  ASSERT(fp.is_valid() && result.is_valid());
+
+  Label exit;
+
+  // Get the number of formal parameters.
+  __ Set(result.reg(), Immediate(Smi::FromInt(scope()->num_parameters())));
+
+  // Check if the calling frame is an arguments adaptor frame.
+  __ mov(fp.reg(), Operand(ebp, StandardFrameConstants::kCallerFPOffset));
+  __ cmp(Operand(fp.reg(), StandardFrameConstants::kContextOffset),
+         Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
+  __ j(not_equal, &exit);
+
+  // Arguments adaptor case: Read the arguments length from the
+  // adaptor frame.
+  __ mov(result.reg(),
+         Operand(fp.reg(), ArgumentsAdaptorFrameConstants::kLengthOffset));
+
+  __ bind(&exit);
+  result.set_type_info(TypeInfo::Smi());
+  if (FLAG_debug_code) __ AbortIfNotSmi(result.reg());
   frame_->Push(&result);
 }
 
@@ -10411,30 +10429,6 @@ void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
 }
 
 
-void ArgumentsAccessStub::GenerateReadLength(MacroAssembler* masm) {
-  // Check if the calling frame is an arguments adaptor frame.
-  __ mov(edx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
-  __ mov(ecx, Operand(edx, StandardFrameConstants::kContextOffset));
-  __ cmp(Operand(ecx), Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
-
-  // Arguments adaptor case: Read the arguments length from the
-  // adaptor frame and return it.
-  // Otherwise nothing to do: The number of formal parameters has already been
-  // passed in register eax by calling function. Just return it.
-  if (CpuFeatures::IsSupported(CMOV)) {
-    CpuFeatures::Scope use_cmov(CMOV);
-    __ cmov(equal, eax,
-            Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
-  } else {
-    Label exit;
-    __ j(not_equal, &exit);
-    __ mov(eax, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
-    __ bind(&exit);
-  }
-  __ ret(0);
-}
-
-
 void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
   // The key is in edx and the parameter count is in eax.
 

src/x64/codegen-x64.cc

@@ -3772,12 +3772,32 @@ void CodeGenerator::GenerateIsConstructCall(ZoneList<Expression*>* args) {
 
 void CodeGenerator::GenerateArgumentsLength(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
-  // ArgumentsAccessStub takes the parameter count as an input argument
-  // in register eax.  Create a constant result for it.
-  Result count(Handle<Smi>(Smi::FromInt(scope()->num_parameters())));
-  // Call the shared stub to get to the arguments.length.
-  ArgumentsAccessStub stub(ArgumentsAccessStub::READ_LENGTH);
-  Result result = frame_->CallStub(&stub, &count);
+
+  Result fp = allocator_->Allocate();
+  Result result = allocator_->Allocate();
+  ASSERT(fp.is_valid() && result.is_valid());
+
+  Label exit;
+
+  // Get the number of formal parameters.
+  __ Move(result.reg(), Smi::FromInt(scope()->num_parameters()));
+
+  // Check if the calling frame is an arguments adaptor frame.
+  __ movq(fp.reg(), Operand(rbp, StandardFrameConstants::kCallerFPOffset));
+  __ SmiCompare(Operand(fp.reg(), StandardFrameConstants::kContextOffset),
+                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+  __ j(not_equal, &exit);
+
+  // Arguments adaptor case: Read the arguments length from the
+  // adaptor frame.
+  __ movq(result.reg(),
+          Operand(fp.reg(), ArgumentsAdaptorFrameConstants::kLengthOffset));
+
+  __ bind(&exit);
+  result.set_type_info(TypeInfo::Smi());
+  if (FLAG_debug_code) {
+    __ AbortIfNotSmi(result.reg(), "Computed arguments.length is not a smi.");
+  }
   frame_->Push(&result);
 }
 
@@ -7787,23 +7807,6 @@ void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
 }
 
 
-void ArgumentsAccessStub::GenerateReadLength(MacroAssembler* masm) {
-  // Check if the calling frame is an arguments adaptor frame.
-  Label adaptor;
-  __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
-  __ SmiCompare(Operand(rdx, StandardFrameConstants::kContextOffset),
-                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-
-  // Arguments adaptor case: Read the arguments length from the
-  // adaptor frame and return it.
-  // Otherwise nothing to do: The number of formal parameters has already been
-  // passed in register eax by calling function. Just return it.
-  __ cmovq(equal, rax,
-           Operand(rdx, ArgumentsAdaptorFrameConstants::kLengthOffset));
-  __ ret(0);
-}
-
-
 void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
   // Check that stack should contain next handler, frame pointer, state and
   // return address in that order.

src/x64/macro-assembler-x64.cc

@@ -1660,6 +1660,15 @@ void MacroAssembler::AbortIfNotNumber(Register object, const char* msg) {
 }
 
 
+void MacroAssembler::AbortIfNotSmi(Register object, const char* msg) {
+  Label ok;
+  Condition is_smi = CheckSmi(object);
+  j(is_smi, &ok);
+  Assert(equal, msg);
+  bind(&ok);
+}
+
+
 Condition MacroAssembler::IsObjectStringType(Register heap_object,
                                              Register map,
                                              Register instance_type) {

src/x64/macro-assembler-x64.h

@@ -503,6 +503,9 @@ class MacroAssembler: public Assembler {
   // Abort execution if argument is not a number. Used in debug code.
   void AbortIfNotNumber(Register object, const char* msg);
 
+  // Abort execution if argument is not a smi. Used in debug code.
+  void AbortIfNotSmi(Register object, const char* msg);
+
   // ---------------------------------------------------------------------------
   // Exception handling