Enable snapshots on MIPS. This is based on

src/mips/macro-assembler-mips.h

 // Copyright 2012 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 63 matching lines @@
   // Don't load NaNs or infinities, branch to the non number case instead.
   AVOID_NANS_AND_INFINITIES = 1 << 1
 };
 
 // Allow programmer to use Branch Delay Slot of Branches, Jumps, Calls.
 enum BranchDelaySlot {
   USE_DELAY_SLOT,
   PROTECT
 };
 
+// Flags used for the li macro-assembler function.
+enum LiFlags {
+  // If the constant value can be represented in just 16 bits, then
+  // optimize the li to use a single instruction, rather than lui/ori pair.
+  OPTIMIZE_SIZE = 0,
+  // Always use 2 instructions (lui/ori pair), even if the constant could
+  // be loaded with just one, so that this value is patchable later.
+  CONSTANT_SIZE = 1
+};
+
 
 enum RememberedSetAction { EMIT_REMEMBERED_SET, OMIT_REMEMBERED_SET };
 enum SmiCheck { INLINE_SMI_CHECK, OMIT_SMI_CHECK };
 enum RAStatus { kRAHasNotBeenSaved, kRAHasBeenSaved };
 
 bool AreAliased(Register r1, Register r2, Register r3, Register r4);
 
 
 // -----------------------------------------------------------------------------
 // Static helper functions.
@@ skipping 83 matching lines @@
   void Call(Handle<Code> code,
             RelocInfo::Mode rmode = RelocInfo::CODE_TARGET,
             unsigned ast_id = kNoASTId,
             COND_ARGS);
   void Ret(COND_ARGS);
   inline void Ret(BranchDelaySlot bd, Condition cond = al,
     Register rs = zero_reg, const Operand& rt = Operand(zero_reg)) {
     Ret(cond, rs, rt, bd);
   }
 
+  void Branch(Label* L,
+              Condition cond,
+              Register rs,
+              Heap::RootListIndex index,
+              BranchDelaySlot bdslot = PROTECT);
+
 #undef COND_ARGS
 
   // Emit code to discard a non-negative number of pointer-sized elements
   // from the stack, clobbering only the sp register.
   void Drop(int count,
             Condition cond = cc_always,
             Register reg = no_reg,
             const Operand& op = Operand(no_reg));
 
   void DropAndRet(int drop = 0,
@@ skipping 40 matching lines @@
 
   // Jump unconditionally to given label.
   // We NEED a nop in the branch delay slot, as it used by v8, for example in
   // CodeGenerator::ProcessDeferred().
   // Currently the branch delay slot is filled by the MacroAssembler.
   // Use rather b(Label) for code generation.
   void jmp(Label* L) {
     Branch(L);
   }
 
-
   // Load an object from the root table.
   void LoadRoot(Register destination,
                 Heap::RootListIndex index);
   void LoadRoot(Register destination,
                 Heap::RootListIndex index,
                 Condition cond, Register src1, const Operand& src2);
 
   // Store an object to the root table.
   void StoreRoot(Register source,
                  Heap::RootListIndex index);
@@ skipping 310 matching lines @@
 #undef DEFINE_INSTRUCTION
 #undef DEFINE_INSTRUCTION2
 
 
   // ---------------------------------------------------------------------------
   // Pseudo-instructions.
 
   void mov(Register rd, Register rt) { or_(rd, rt, zero_reg); }
 
   // Load int32 in the rd register.
-  void li(Register rd, Operand j, bool gen2instr = false);
-  inline void li(Register rd, int32_t j, bool gen2instr = false) {
-    li(rd, Operand(j), gen2instr);
+  void li(Register rd, Operand j, LiFlags mode = OPTIMIZE_SIZE);
+  inline void li(Register rd, int32_t j, LiFlags mode = OPTIMIZE_SIZE) {
+    li(rd, Operand(j), mode);
   }
-  inline void li(Register dst, Handle<Object> value, bool gen2instr = false) {
-    li(dst, Operand(value), gen2instr);
+  inline void li(Register dst, Handle<Object> value,
+                 LiFlags mode = OPTIMIZE_SIZE) {
+    li(dst, Operand(value), mode);
   }
 
   // Push multiple registers on the stack.
   // Registers are saved in numerical order, with higher numbered registers
   // saved in higher memory addresses.
   void MultiPush(RegList regs);
   void MultiPushReversed(RegList regs);
 
   void MultiPushFPU(RegList regs);
   void MultiPushReversedFPU(RegList regs);
@@ skipping 892 matching lines @@
 #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
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_