Unravel kHeapObjectTagSize from the stub cache.

src/arm64/stub-cache-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/ic-inl.h"
@@ skipping 159 matching lines @@
 
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(receiver, &miss);
 
   // Compute the hash for primary table.
   __ Ldr(scratch, FieldMemOperand(name, Name::kHashFieldOffset));
   __ Ldr(extra, FieldMemOperand(receiver, HeapObject::kMapOffset));
   __ Add(scratch, scratch, extra);
   __ Eor(scratch, scratch, flags);
   // We shift out the last two bits because they are not part of the hash.
-  __ Ubfx(scratch, scratch, kHeapObjectTagSize,
+  __ Ubfx(scratch, scratch, kCacheIndexShift,
           CountTrailingZeros(kPrimaryTableSize, 64));
 
   // Probe the primary table.
   ProbeTable(isolate, masm, flags, kPrimary, receiver, name,
       scratch, extra, extra2, extra3);
 
   // Primary miss: Compute hash for secondary table.
-  __ Sub(scratch, scratch, Operand(name, LSR, kHeapObjectTagSize));
-  __ Add(scratch, scratch, flags >> kHeapObjectTagSize);
+  __ Sub(scratch, scratch, Operand(name, LSR, kCacheIndexShift));
+  __ Add(scratch, scratch, flags >> kCacheIndexShift);
   __ And(scratch, scratch, kSecondaryTableSize - 1);
 
   // Probe the secondary table.
   ProbeTable(isolate, masm, flags, kSecondary, receiver, name,
       scratch, extra, extra2, extra3);
 
   // Cache miss: Fall-through and let caller handle the miss by
   // entering the runtime system.
   __ Bind(&miss);
   __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1,
@@ skipping 1277 matching lines @@
 
   // Miss case, call the runtime.
   __ Bind(&miss);
   TailCallBuiltin(masm, Builtins::kKeyedLoadIC_Miss);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64