[stubs] Simplify the ArrayConstructorStub.

src/x64/code-stubs-x64.cc

 // Copyright 2013 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 1306 matching lines @@
 
 void CallICStub::HandleArrayCase(MacroAssembler* masm, Label* miss) {
   // rdi - function
   // rdx - slot id
   // rbx - vector
   // rcx - allocation site (loaded from vector[slot]).
   __ LoadNativeContextSlot(Context::ARRAY_FUNCTION_INDEX, r8);
   __ cmpp(rdi, r8);
   __ j(not_equal, miss);
 
-  __ movp(rax, Immediate(arg_count()));
-
   // Increment the call count for monomorphic function calls.
   IncrementCallCount(masm, rbx, rdx);
 
   __ movp(rbx, rcx);
   __ movp(rdx, rdi);
-  ArrayConstructorStub stub(masm->isolate(), arg_count());
+  __ Set(rax, arg_count());
+  ArrayConstructorStub stub(masm->isolate());
   __ TailCallStub(&stub);
 }
 
 
 void CallICStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   // -- rdi - function
   // -- rdx - slot id
   // -- rbx - vector
   // -----------------------------------
@@ skipping 2187 matching lines @@
   ElementsKind kinds[2] = { FAST_ELEMENTS, FAST_HOLEY_ELEMENTS };
   for (int i = 0; i < 2; i++) {
     // For internal arrays we only need a few things
     InternalArrayNoArgumentConstructorStub stubh1(isolate, kinds[i]);
     stubh1.GetCode();
     InternalArraySingleArgumentConstructorStub stubh2(isolate, kinds[i]);
     stubh2.GetCode();
   }
 }
 
+void ArrayConstructorStub::GenerateDispatchToArrayStub(
+    MacroAssembler* masm, AllocationSiteOverrideMode mode) {
+  Label not_zero_case, not_one_case;
+  __ testp(rax, rax);
+  __ j(not_zero, &not_zero_case);
+  CreateArrayDispatch<ArrayNoArgumentConstructorStub>(masm, mode);
 
-void ArrayConstructorStub::GenerateDispatchToArrayStub(
-    MacroAssembler* masm,
-    AllocationSiteOverrideMode mode) {
-  if (argument_count() == ANY) {
-    Label not_zero_case, not_one_case;
-    __ testp(rax, rax);
-    __ j(not_zero, &not_zero_case);
-    CreateArrayDispatch<ArrayNoArgumentConstructorStub>(masm, mode);
+  __ bind(&not_zero_case);
+  __ cmpl(rax, Immediate(1));
+  __ j(greater, &not_one_case);
+  CreateArrayDispatchOneArgument(masm, mode);
 
-    __ bind(&not_zero_case);
-    __ cmpl(rax, Immediate(1));
-    __ j(greater, &not_one_case);
-    CreateArrayDispatchOneArgument(masm, mode);
-
-    __ bind(&not_one_case);
-    ArrayNArgumentsConstructorStub stub(masm->isolate());
-    __ TailCallStub(&stub);
-  } else if (argument_count() == NONE) {
-    CreateArrayDispatch<ArrayNoArgumentConstructorStub>(masm, mode);
-  } else if (argument_count() == ONE) {
-    CreateArrayDispatchOneArgument(masm, mode);
-  } else if (argument_count() == MORE_THAN_ONE) {
-    ArrayNArgumentsConstructorStub stub(masm->isolate());
-    __ TailCallStub(&stub);
-  } else {
-    UNREACHABLE();
-  }
+  __ bind(&not_one_case);
+  ArrayNArgumentsConstructorStub stub(masm->isolate());
+  __ TailCallStub(&stub);
 }
 
-
 void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax    : argc
   //  -- rbx    : AllocationSite or undefined
   //  -- rdi    : constructor
   //  -- rdx    : new target
   //  -- rsp[0] : return address
   //  -- rsp[8] : last argument
   // -----------------------------------
   if (FLAG_debug_code) {
@@ skipping 31 matching lines @@
   __ SmiToInteger32(rdx, rdx);
   STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
   __ andp(rdx, Immediate(AllocationSite::ElementsKindBits::kMask));
   GenerateDispatchToArrayStub(masm, DONT_OVERRIDE);
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
 
   // Subclassing
   __ bind(&subclassing);
-  switch (argument_count()) {
-    case ANY:
-    case MORE_THAN_ONE: {
-      StackArgumentsAccessor args(rsp, rax);
-      __ movp(args.GetReceiverOperand(), rdi);
-      __ addp(rax, Immediate(3));
-      break;
-    }
-    case NONE: {
-      StackArgumentsAccessor args(rsp, 0);
-      __ movp(args.GetReceiverOperand(), rdi);
-      __ Set(rax, 3);
-      break;
-    }
-    case ONE: {
-      StackArgumentsAccessor args(rsp, 1);
-      __ movp(args.GetReceiverOperand(), rdi);
-      __ Set(rax, 4);
-      break;
-    }
-  }
+  StackArgumentsAccessor args(rsp, rax);
+  __ movp(args.GetReceiverOperand(), rdi);
+  __ addp(rax, Immediate(3));
   __ PopReturnAddressTo(rcx);
   __ Push(rdx);
   __ Push(rbx);
   __ PushReturnAddressFrom(rcx);
   __ JumpToExternalReference(ExternalReference(Runtime::kNewArray, isolate()));
 }
 
 
 void InternalArrayConstructorStub::GenerateCase(
     MacroAssembler* masm, ElementsKind kind) {
@@ skipping 1240 matching lines @@
                            kStackUnwindSpace, nullptr, return_value_operand,
                            NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64