Optimize loads from root-array in X64.

src/x64/macro-assembler-x64.cc

 // Copyright 2011 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 31 matching lines @@
 
 MacroAssembler::MacroAssembler(void* buffer, int size)
     : Assembler(buffer, size),
       generating_stub_(false),
       allow_stub_calls_(true),
       code_object_(Heap::undefined_value()) {
 }
 
 
 void MacroAssembler::LoadRoot(Register destination, Heap::RootListIndex index) {
-  movq(destination, Operand(kRootRegister, index << kPointerSizeLog2));
+  movq(destination, Operand(kRootRegister,
+                            (index << kPointerSizeLog2) - kRootRegisterBias));
+}
+
+
+void MacroAssembler::LoadRootIndexed(Register destination,
+                                     Register variable_offset,
+                                     int fixed_offset) {
+  movq(destination,
+       Operand(kRootRegister,
+               variable_offset, times_pointer_size,
+               (fixed_offset << kPointerSizeLog2) - kRootRegisterBias));
 }
 
 
 void MacroAssembler::StoreRoot(Register source, Heap::RootListIndex index) {
-  movq(Operand(kRootRegister, index << kPointerSizeLog2), source);
+  movq(Operand(kRootRegister, (index << kPointerSizeLog2) - kRootRegisterBias),
+       source);
 }
 
 
 void MacroAssembler::PushRoot(Heap::RootListIndex index) {
-  push(Operand(kRootRegister, index << kPointerSizeLog2));
+  push(Operand(kRootRegister, (index << kPointerSizeLog2) - kRootRegisterBias));
 }
 
 
 void MacroAssembler::CompareRoot(Register with, Heap::RootListIndex index) {
-  cmpq(with, Operand(kRootRegister, index << kPointerSizeLog2));
+  cmpq(with, Operand(kRootRegister,
+                     (index << kPointerSizeLog2) - kRootRegisterBias));
 }
 
 
 void MacroAssembler::CompareRoot(const Operand& with,
                                  Heap::RootListIndex index) {
   ASSERT(!with.AddressUsesRegister(kScratchRegister));
   LoadRoot(kScratchRegister, index);
   cmpq(with, kScratchRegister);
 }
 
@@ skipping 2573 matching lines @@
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64