[stubs] StringToNumberStub --> StringToNumber builtin.

src/arm64/builtins-arm64.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_ARM64
 
 #include "src/arm64/frames-arm64.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
@@ skipping 2764 matching lines @@
   //  -- x1 : requested object size (untagged)
   //  -- lr : return address
   // -----------------------------------
   __ SmiTag(x1);
   __ Move(x2, Smi::FromInt(AllocateTargetSpace::encode(OLD_SPACE)));
   __ Push(x1, x2);
   __ Move(cp, Smi::FromInt(0));
   __ TailCallRuntime(Runtime::kAllocateInTargetSpace);
 }
 
+void Builtins::Generate_StringToNumber(MacroAssembler* masm) {
+  // The StringToNumber stub takes one argument in x0.
+  __ AssertString(x0);
+
+  // Check if string has a cached array index.
+  Label runtime;
+  __ Ldr(x2, FieldMemOperand(x0, String::kHashFieldOffset));
+  __ Tst(x2, Operand(String::kContainsCachedArrayIndexMask));
+  __ B(ne, &runtime);
+  __ IndexFromHash(x2, x0);
+  __ Ret();
+
+  __ Bind(&runtime);
+  __ Push(x0);  // Push argument.
+  __ TailCallRuntime(Runtime::kStringToNumber);
+}
+
 void Builtins::Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm) {
   ASM_LOCATION("Builtins::Generate_ArgumentsAdaptorTrampoline");
   // ----------- S t a t e -------------
   //  -- x0 : actual number of arguments
   //  -- x1 : function (passed through to callee)
   //  -- x2 : expected number of arguments
   //  -- x3 : new target (passed through to callee)
   // -----------------------------------
 
   Register argc_actual = x0;  // Excluding the receiver.
@@ skipping 132 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM