Fix object initialization when slack tracking for it's map is still enabled.

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/arm64/assembler-arm64.h"
@@ skipping 1020 matching lines @@
   // The 'temps' list is a list of X registers which can be used for scratch
   // values. The temps list must include at least one register.
   //
   // Currently, CopyFields cannot make use of more than three registers from
   // the 'temps' list.
   //
   // CopyFields expects to be able to take at least two registers from
   // MacroAssembler::TmpList().
   void CopyFields(Register dst, Register src, CPURegList temps, unsigned count);
 
-  // Starting at address in dst, initialize field_count 64-bit fields with
-  // 64-bit value in register filler. Register dst is corrupted.
-  void FillFields(Register dst,
-                  Register field_count,
-                  Register filler);
+  // Initialize fields with filler values.  Fields starting at |current_address|
+  // not including |end_address| are overwritten with the value in |filler|.  At
+  // the end the loop, |current_address| takes the value of |end_address|.
+  void InitializeFieldsWithFiller(Register current_address,
+                                  Register end_address, Register filler);
 
   // Copies a number of bytes from src to dst. All passed registers are
   // clobbered. On exit src and dst will point to the place just after where the
   // last byte was read or written and length will be zero. Hint may be used to
   // determine which is the most efficient algorithm to use for copying.
   void CopyBytes(Register dst,
                  Register src,
                  Register length,
                  Register scratch,
                  CopyHint hint = kCopyUnknown);
@@ skipping 234 matching lines @@
   // ---------------------------------------------------------------------------
   // Allocation support
 
   // Allocate an object in new space or old space. The object_size is
   // specified either in bytes or in words if the allocation flag SIZE_IN_WORDS
   // is passed. The allocated object is returned in result.
   //
   // If the new space is exhausted control continues at the gc_required label.
   // In this case, the result and scratch registers may still be clobbered.
   // If flags includes TAG_OBJECT, the result is tagged as as a heap object.
-  void Allocate(Register object_size,
-                Register result,
-                Register scratch1,
-                Register scratch2,
-                Label* gc_required,
-                AllocationFlags flags);
+  void Allocate(Register object_size, Register result, Register result_end,
+                Register scratch, Label* gc_required, AllocationFlags flags);
 
   void Allocate(int object_size,
                 Register result,
                 Register scratch1,
                 Register scratch2,
                 Label* gc_required,
                 AllocationFlags flags);
 
   void AllocateTwoByteString(Register result,
                              Register length,
@@ skipping 973 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_