Reland parts of 'Use weak cells in map checks in polymorphic ICs'

src/arm64/macro-assembler-arm64.h

 // 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.
 
 #ifndef V8_ARM64_MACRO_ASSEMBLER_ARM64_H_
 #define V8_ARM64_MACRO_ASSEMBLER_ARM64_H_
 
 #include <vector>
 
 #include "src/bailout-reason.h"
@@ skipping 1469 matching lines @@
 
   // Check if the map of an object is equal to a specified map and branch to a
   // specified target if equal. Skip the smi check if not required (object is
   // known to be a heap object)
   void DispatchMap(Register obj,
                    Register scratch,
                    Handle<Map> map,
                    Handle<Code> success,
                    SmiCheckType smi_check_type);
 
+  // Compare the given value and the value of weak cell.
+  void CmpWeakValue(Register value, Handle<WeakCell> cell, Register scratch);
+
+  // Load the value of the weak cell in the value register. Branch to the given
+  // miss label if the weak cell was cleared.
+  void LoadWeakValue(Register value, Handle<WeakCell> cell, Label* miss);
+
   // Test the bitfield of the heap object map with mask and set the condition
   // flags. The object register is preserved.
   void TestMapBitfield(Register object, uint64_t mask);
 
   // Load the elements kind field from a map, and return it in the result
   // register.
   void LoadElementsKindFromMap(Register result, Register map);
 
   // Compare the object in a register to a value from the root list.
   void CompareRoot(const Register& obj, Heap::RootListIndex index);
@@ skipping 830 matching lines @@
 #error "Unsupported option"
 #define CODE_COVERAGE_STRINGIFY(x) #x
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 #endif  // V8_ARM64_MACRO_ASSEMBLER_ARM64_H_