Subzero. Performance tweaks.

src/IceMemory.h

+//===- subzero/src/IceMemory.h - Memory management declarations -*- C++ -*-===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Declares some useful data structures and routines dealing with
+/// memory management in Subzero (mostly, allocator types.)
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SUBZERO_SRC_ICEMEMORY_H
+#define SUBZERO_SRC_ICEMEMORY_H
+
+#include "IceTLS.h"
+
+#include "llvm/Support/Allocator.h"
+
+#include <cstddef>
+#include <mutex>
+
+namespace Ice {
+
+class Cfg;
+class GlobalContext;
+
+using ArenaAllocator =
+    llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, /*SlabSize=*/1024 * 1024>;
+
+class LockedArenaAllocator {
+  LockedArenaAllocator() = delete;
+  LockedArenaAllocator(const LockedArenaAllocator &) = delete;
+  LockedArenaAllocator &operator=(const LockedArenaAllocator &) = delete;
+
+public:
+  LockedArenaAllocator(ArenaAllocator *Alloc, std::mutex *Mutex)
+      : Alloc(Alloc), AutoLock(*Mutex) {}
+  LockedArenaAllocator(LockedArenaAllocator &&) = default;
+  LockedArenaAllocator &operator=(LockedArenaAllocator &&) = default;
+  ~LockedArenaAllocator() = default;
+
+  ArenaAllocator *operator->() { return Alloc; }
+
+private:
+  ArenaAllocator *Alloc;
+  std::unique_lock<std::mutex> AutoLock;
+};
+
+template <typename T, typename Traits> struct sz_allocator {
+  /// std::allocator interface implementation.
+  /// @{
+  using value_type = T;
+  using pointer = T *;
+  using const_pointer = const T *;
+  using reference = T &;
+  using const_reference = const T &;
+  using size_type = std::size_t;
+  using difference_type = std::ptrdiff_t;
+
+  sz_allocator() = default;
+  template <class U> sz_allocator(const sz_allocator<U, Traits> &) {}
+
+  pointer address(reference x) const {
+    return reinterpret_cast<pointer>(&reinterpret_cast<char &>(x));
+  }
+  const_pointer address(const_reference x) const {
+    return reinterpret_cast<const_pointer>(&reinterpret_cast<const char &>(x));
+  }
+
+  pointer allocate(size_type num) {
+    return current()->template Allocate<T>(num);
+  }
+
+  template <typename... A> void construct(pointer P, A &&... Args) {
+    new (static_cast<void *>(P)) T(std::forward<A>(Args)...);
+  }
+
+  void deallocate(pointer, size_type) {}
+
+  template <class U> struct rebind { typedef sz_allocator<U, Traits> other; };
+
+  void destroy(pointer P) { P->~T(); }
+  /// @}
+
+  /// Manages the current underlying allocator.
+  /// @{
+  static typename Traits::allocator_type current() { return Traits::current(); }
+  static void init() { Traits::init(); }
+  /// @}
+};
+
+template <class Traits> struct sz_allocator_scope {
+  explicit sz_allocator_scope(typename Traits::manager_type *Manager) {
+    Traits::set_current(Manager);
+  }
+
+  ~sz_allocator_scope() { Traits::set_current(nullptr); }
+};
+
+template <typename T, typename U, typename Traits>
+inline bool operator==(const sz_allocator<T, Traits> &,
+                       const sz_allocator<U, Traits> &) {
+  return true;
+}
+
+template <typename T, typename U, typename Traits>
+inline bool operator!=(const sz_allocator<T, Traits> &,
+                       const sz_allocator<U, Traits> &) {
+  return false;
+}
+
+class CfgAllocatorTraits {
+  CfgAllocatorTraits() = delete;
+  CfgAllocatorTraits(const CfgAllocatorTraits &) = delete;
+  CfgAllocatorTraits &operator=(const CfgAllocatorTraits &) = delete;
+  ~CfgAllocatorTraits() = delete;
+
+public:
+  using allocator_type = ArenaAllocator *;
+  using manager_type = Cfg;
+
+  static void init() { ICE_TLS_INIT_FIELD(CfgAllocator); };
+
+  static allocator_type current();
+  static void set_current(const manager_type *Manager);
+
+private:
+  ICE_TLS_DECLARE_FIELD(ArenaAllocator *, CfgAllocator);
+};
+
+template <typename T>
+using CfgLocalAllocator = sz_allocator<T, CfgAllocatorTraits>;
+
+using CfgLocalAllocatorScope = sz_allocator_scope<CfgAllocatorTraits>;
+
+} // end of namespace Ice
+
+#endif // SUBZERO_SRC_ICEMEMORY_H