MIPS64: Enable shorten-64-to-32 warning.

src/mips64/assembler-mips64.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 386 matching lines @@
 // On MIPS we have only one adressing mode with base_reg + offset.
 // Class MemOperand represents a memory operand in load and store instructions.
 class MemOperand : public Operand {
  public:
   // Immediate value attached to offset.
   enum OffsetAddend {
     offset_minus_one = -1,
     offset_zero = 0
   };
 
-  explicit MemOperand(Register rn, int64_t offset = 0);
-  explicit MemOperand(Register rn, int64_t unit, int64_t multiplier,
+  explicit MemOperand(Register rn, int32_t offset = 0);
+  explicit MemOperand(Register rn, int32_t unit, int32_t multiplier,
                       OffsetAddend offset_addend = offset_zero);
   int32_t offset() const { return offset_; }
 
   bool OffsetIsInt16Encodable() const {
     return is_int16(offset_);
   }
 
  private:
   int32_t offset_;
 
@@ skipping 712 matching lines @@
   // Postpone the generation of the trampoline pool for the specified number of
   // instructions.
   void BlockTrampolinePoolFor(int instructions);
 
   // Check if there is less than kGap bytes available in the buffer.
   // If this is the case, we need to grow the buffer before emitting
   // an instruction or relocation information.
   inline bool overflow() const { return pc_ >= reloc_info_writer.pos() - kGap; }
 
   // Get the number of bytes available in the buffer.
-  inline int available_space() const { return reloc_info_writer.pos() - pc_; }
+  inline intptr_t available_space() const {
+    return reloc_info_writer.pos() - pc_;
+  }
 
   // Read/patch instructions.
   static Instr instr_at(byte* pc) { return *reinterpret_cast<Instr*>(pc); }
   static void instr_at_put(byte* pc, Instr instr) {
     *reinterpret_cast<Instr*>(pc) = instr;
   }
   Instr instr_at(int pos) { return *reinterpret_cast<Instr*>(buffer_ + pos); }
   void instr_at_put(int pos, Instr instr) {
     *reinterpret_cast<Instr*>(buffer_ + pos) = instr;
   }
@@ skipping 331 matching lines @@
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBuffer();
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_ASSEMBLER_MIPS_H_