Subzero. Performance tweaks.

src/IceMemory.cpp

+//===- subzero/src/IceMemory.cpp - Memory management definitions -*- C++ -*-==//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Implements memory management related routines for subzero.
+/////
+//===----------------------------------------------------------------------===//
+
+#include "IceMemory.h"
+
+#include "IceCfg.h"
+#include "IceTLS.h"
+
+#include <cassert>
+#include <utility>
+
+namespace Ice {
+ICE_TLS_DEFINE_FIELD(ArenaAllocator *, CfgAllocatorTraits, CfgAllocator);
+
+CfgAllocatorTraits::allocator_type CfgAllocatorTraits::current() {
+  return ICE_TLS_GET_FIELD(CfgAllocator);
+}
+
+void CfgAllocatorTraits::set_current(const manager_type *Manager) {
+  ArenaAllocator *Allocator =
+      Manager == nullptr ? nullptr : Manager->Allocator.get();
+  ICE_TLS_SET_FIELD(CfgAllocator, Allocator);
+}
+
+} // end of namespace Ice