ARM64: Introduce a version of ADR handling distant targets.

src/arm64/assembler-arm64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1483 matching lines @@
   void isb();
 
   // Alias for system instructions.
   void nop() { hint(NOP); }
 
   // Different nop operations are used by the code generator to detect certain
   // states of the generated code.
   enum NopMarkerTypes {
     DEBUG_BREAK_NOP,
     INTERRUPT_CODE_NOP,
+    ADR_FAR_NOP,
     FIRST_NOP_MARKER = DEBUG_BREAK_NOP,
-    LAST_NOP_MARKER = INTERRUPT_CODE_NOP
+    LAST_NOP_MARKER = ADR_FAR_NOP
   };
 
   void nop(NopMarkerTypes n) {
     ASSERT((FIRST_NOP_MARKER <= n) && (n <= LAST_NOP_MARKER));
     mov(Register::XRegFromCode(n), Register::XRegFromCode(n));
   }
 
   // FP instructions.
   // Move immediate to FP register.
   void fmov(FPRegister fd, double imm);
@@ skipping 697 matching lines @@
     ASSERT(is_const_pool_blocked());
     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(num_pending_reloc_info() == 0);
     // Flush the Instruction cache.
     size_t length = buffer_size_ - kGap;
     CPU::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);
 };
 
 
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBuffer();
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_H_