Simplify some code related to x64 calling convention.

src/x64/full-codegen-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 2983 matching lines @@
   __ bind(&slow_allocate_heapnumber);
   // Allocate a heap number.
   __ CallRuntime(Runtime::kNumberAlloc, 0);
   __ movq(rbx, rax);
 
   __ bind(&heapnumber_allocated);
 
   // Return a random uint32 number in rax.
   // The fresh HeapNumber is in rbx, which is callee-save on both x64 ABIs.
   __ PrepareCallCFunction(1);
-#ifdef _WIN64
-  __ movq(rcx,
+  __ movq(arg_reg_1,
           ContextOperand(context_register(), Context::GLOBAL_OBJECT_INDEX));
-  __ movq(rcx, FieldOperand(rcx, GlobalObject::kNativeContextOffset));
-
-#else
-  __ movq(rdi,
-          ContextOperand(context_register(), Context::GLOBAL_OBJECT_INDEX));
-  __ movq(rdi, FieldOperand(rdi, GlobalObject::kNativeContextOffset));
-#endif
+  __ movq(arg_reg_1,
+          FieldOperand(arg_reg_1, GlobalObject::kNativeContextOffset));
   __ CallCFunction(ExternalReference::random_uint32_function(isolate()), 1);
 
   // Convert 32 random bits in rax to 0.(32 random bits) in a double
   // by computing:
   // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
   __ movl(rcx, Immediate(0x49800000));  // 1.0 x 2^20 as single.
   __ movd(xmm1, rcx);
   __ movd(xmm0, rax);
   __ cvtss2sd(xmm1, xmm1);
   __ xorps(xmm0, xmm1);
@@ skipping 77 matching lines @@
       Operand stamp_operand = __ ExternalOperand(stamp);
       __ movq(scratch, stamp_operand);
       __ cmpq(scratch, FieldOperand(object, JSDate::kCacheStampOffset));
       __ j(not_equal, &runtime, Label::kNear);
       __ movq(result, FieldOperand(object, JSDate::kValueOffset +
                                            kPointerSize * index->value()));
       __ jmp(&done);
     }
     __ bind(&runtime);
     __ PrepareCallCFunction(2);
-#ifdef _WIN64
-  __ movq(rcx, object);
-  __ movq(rdx, index, RelocInfo::NONE64);
-#else
-  __ movq(rdi, object);
-  __ movq(rsi, index, RelocInfo::NONE64);
-#endif
+  __ movq(arg_reg_1, object);
+  __ movq(arg_reg_2, index, RelocInfo::NONE64);
     __ CallCFunction(ExternalReference::get_date_field_function(isolate()), 2);
     __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
     __ jmp(&done);
   }
 
   __ bind(&not_date_object);
   __ CallRuntime(Runtime::kThrowNotDateError, 0);
   __ bind(&done);
   context()->Plug(rax);
 }
@@ skipping 1473 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64