[arm64] Add assertions to Claim and Drop.

src/arm64/macro-assembler-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/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 1651 matching lines @@
     STATIC_ASSERT(kSmiTag == 0);
     Tst(object, kSmiTagMask);
     Check(ne, kOperandIsASmiAndNotAString);
     Ldr(temp, FieldMemOperand(object, HeapObject::kMapOffset));
     CompareInstanceType(temp, temp, FIRST_NONSTRING_TYPE);
     Check(lo, kOperandIsNotAString);
   }
 }
 
 
+void MacroAssembler::AssertPositiveOrZero(Register value) {
+  if (emit_debug_code()) {
+    Label done;
+    int sign_bit = value.Is64Bits() ? kXSignBit : kWSignBit;
+    Tbz(value, sign_bit, &done);
+    Abort(kUnexpectedNegativeValue);
+    Bind(&done);
+  }
+}
+
+
 void MacroAssembler::CallStub(CodeStub* stub, TypeFeedbackId ast_id) {
   DCHECK(AllowThisStubCall(stub));  // Stub calls are not allowed in some stubs.
   Call(stub->GetCode(), RelocInfo::CODE_TARGET, ast_id);
 }
 
 
 void MacroAssembler::TailCallStub(CodeStub* stub) {
   Jump(stub->GetCode(), RelocInfo::CODE_TARGET);
 }
 
@@ skipping 3185 matching lines @@
 }
 
 
 #undef __
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64