Use register allocator for context on x64.

src/x64/macro-assembler-x64.cc

 // 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 291 matching lines @@
 
 
 void MacroAssembler::RecordWriteField(
     Register object,
     int offset,
     Register value,
     Register dst,
     SaveFPRegsMode save_fp,
     RememberedSetAction remembered_set_action,
     SmiCheck smi_check) {
-  // The compiled code assumes that record write doesn't change the
-  // context register, so we check that none of the clobbered
-  // registers are rsi.
-  ASSERT(!value.is(rsi) && !dst.is(rsi));
-
   // First, check if a write barrier is even needed. The tests below
   // catch stores of Smis.
   Label done;
 
   // Skip barrier if writing a smi.
   if (smi_check == INLINE_SMI_CHECK) {
     JumpIfSmi(value, &done);
   }
 
   // Although the object register is tagged, the offset is relative to the start
@@ skipping 56 matching lines @@
   }
 }
 
 
 void MacroAssembler::RecordWrite(Register object,
                                  Register address,
                                  Register value,
                                  SaveFPRegsMode fp_mode,
                                  RememberedSetAction remembered_set_action,
                                  SmiCheck smi_check) {
-  // The compiled code assumes that record write doesn't change the
-  // context register, so we check that none of the clobbered
-  // registers are rsi.
-  ASSERT(!value.is(rsi) && !address.is(rsi));
-
   ASSERT(!object.is(value));
   ASSERT(!object.is(address));
   ASSERT(!value.is(address));
   AssertNotSmi(object);
 
   if (remembered_set_action == OMIT_REMEMBERED_SET &&
       !FLAG_incremental_marking) {
     return;
   }
 
@@ skipping 4556 matching lines @@
   movq(arg_reg_1, isolate, RelocInfo::EXTERNAL_REFERENCE);
   CallCFunction(
       ExternalReference::record_object_allocation_function(isolate), 3);
   PopSafepointRegisters();
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64