A64: Use a scope utility to allocate scratch registers.

src/a64/deoptimizer-a64.cc

 // 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 320 matching lines @@
   __ Br(continuation);
 }
 
 
 // Size of an entry of the second level deopt table.
 // This is the code size generated by GeneratePrologue for one entry.
 const int Deoptimizer::table_entry_size_ = 2 * kInstructionSize;
 
 
 void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
+  UseScratchRegisterScope temps(masm());
+  Register entry_id = temps.AcquireX();
+
   // Create a sequence of deoptimization entries.
   // Note that registers are still live when jumping to an entry.
   Label done;
   {
     InstructionAccurateScope scope(masm());
 
     // The number of entry will never exceed kMaxNumberOfEntries.
     // As long as kMaxNumberOfEntries is a valid 16 bits immediate you can use
     // a movz instruction to load the entry id.
     ASSERT(is_uint16(Deoptimizer::kMaxNumberOfEntries));
 
     for (int i = 0; i < count(); i++) {
       int start = masm()->pc_offset();
       USE(start);
-      __ movz(masm()->Tmp0(), i);
+      __ movz(entry_id, i);
       __ b(&done);
       ASSERT(masm()->pc_offset() - start == table_entry_size_);
     }
   }
   __ Bind(&done);
-  // TODO(all): We need to add some kind of assertion to verify that Tmp0()
-  // is not clobbered by Push.
-  __ Push(masm()->Tmp0());
+  __ Push(entry_id);
 }
 
 
 void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
   SetFrameSlot(offset, value);
 }
 
 
 void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
   SetFrameSlot(offset, value);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal