ARM64: Use UntagSmi helpers and clean up assertions.

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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/codegen.h"
 #include "src/debug.h"
@@ skipping 1228 matching lines @@
     // We are not trying to catch interruptions (e.g. debug break and
     // preemption) here, so the "real stack limit" is checked.
     Label enough_stack_space;
     __ LoadRoot(x10, Heap::kRealStackLimitRootIndex);
     __ Ldr(function, MemOperand(fp, kFunctionOffset));
     // Make x10 the space we have left. The stack might already be overflowed
     // here which will cause x10 to become negative.
     // TODO(jbramley): Check that the stack usage here is safe.
     __ Sub(x10, jssp, x10);
     // Check if the arguments will overflow the stack.
-    __ Cmp(x10, Operand(argc, LSR, kSmiShift - kPointerSizeLog2));
+    __ Cmp(x10, Operand::UntagSmiAndScale(argc, kPointerSizeLog2));
     __ B(gt, &enough_stack_space);
     // There is not enough stack space, so use a builtin to throw an appropriate
     // error.
     __ Push(function, argc);
     __ InvokeBuiltin(Builtins::STACK_OVERFLOW, CALL_FUNCTION);
     // We should never return from the APPLY_OVERFLOW builtin.
     if (__ emit_debug_code()) {
       __ Unreachable();
     }
 
@@ skipping 296 matching lines @@
     __ Unreachable();
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM