ARM64: Change some incorect uses of ptrdiff_t to int64_t.

src/arm64/instructions-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_INSTRUCTIONS_ARM64_H_
 #define V8_ARM64_INSTRUCTIONS_ARM64_H_
 
 #include "src/arm64/constants-arm64.h"
 #include "src/arm64/utils-arm64.h"
 #include "src/globals.h"
@@ skipping 320 matching lines @@
     // which is encoded as
     //   orr r<n>, xzr, r<n>
     return (Mask(LogicalShiftedMask) == ORR_x) &&
            (Rd() == Rm()) &&
            (Rd() == n);
   }
 
   // Find the PC offset encoded in this instruction. 'this' may be a branch or
   // a PC-relative addressing instruction.
   // The offset returned is unscaled.
-  ptrdiff_t ImmPCOffset();
+  int64_t ImmPCOffset();
 
   // Find the target of this instruction. 'this' may be a branch or a
   // PC-relative addressing instruction.
   Instruction* ImmPCOffsetTarget();
 
   static bool IsValidImmPCOffset(ImmBranchType branch_type, int32_t offset);
   bool IsTargetInImmPCOffsetRange(Instruction* target);
   // Patch a PC-relative offset to refer to 'target'. 'this' may be a branch or
   // a PC-relative addressing instruction.
   void SetImmPCOffsetTarget(Instruction* target);
@@ skipping 148 matching lines @@
   TRACE_ENABLE   = 1 << 6,
   TRACE_DISABLE  = 2 << 6,
   TRACE_OVERRIDE = 3 << 6
 };
 
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_ARM64_INSTRUCTIONS_ARM64_H_