ARM64: improve Adr patching

src/arm64/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_ASSEMBLER_ARM64_H_
 #define V8_ARM64_ASSEMBLER_ARM64_H_
 
 #include <list>
 #include <map>
 #include <vector>
@@ skipping 2268 matching lines @@
     EndBlockPools();
     // Verify we have generated the number of instruction we expected.
     ASSERT((pc_offset() + kGap) == buffer_size_);
     // Verify no relocation information has been emitted.
     ASSERT(IsConstPoolEmpty());
     // Flush the Instruction cache.
     size_t length = buffer_size_ - kGap;
     CpuFeatures::FlushICache(buffer_, length);
   }
 
-  static const int kMovInt64NInstrs = 4;
-  void MovInt64(const Register& rd, int64_t imm);
-
   // See definition of PatchAdrFar() for details.
-  static const int kAdrFarPatchableNNops = kMovInt64NInstrs - 1;
-  static const int kAdrFarPatchableNInstrs = kAdrFarPatchableNNops + 3;
-  void PatchAdrFar(Instruction* target);
+  static const int kAdrFarPatchableNNops = 2;
+  static const int kAdrFarPatchableNInstrs = kAdrFarPatchableNNops + 2;
+  void PatchAdrFar(ptrdiff_t target_offset);
 };
 
 
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBufferSpace();
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_H_