| //=== Registry.h - Linker-supported plugin registries -----------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Defines a registry template for discovering pluggable modules. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_SUPPORT_REGISTRY_H |
| #define LLVM_SUPPORT_REGISTRY_H |
| |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/iterator_range.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/DynamicLibrary.h" |
| #include <memory> |
| |
| namespace llvm { |
| /// A simple registry entry which provides only a name, description, and |
| /// no-argument constructor. |
| template <typename T> |
| class SimpleRegistryEntry { |
| StringRef Name, Desc; |
| std::unique_ptr<T> (*Ctor)(); |
| |
| public: |
| SimpleRegistryEntry(StringRef N, StringRef D, std::unique_ptr<T> (*C)()) |
| : Name(N), Desc(D), Ctor(C) {} |
| |
| StringRef getName() const { return Name; } |
| StringRef getDesc() const { return Desc; } |
| std::unique_ptr<T> instantiate() const { return Ctor(); } |
| }; |
| |
| /// A global registry used in conjunction with static constructors to make |
| /// pluggable components (like targets or garbage collectors) "just work" when |
| /// linked with an executable. |
| template <typename T> |
| class Registry { |
| public: |
| typedef T type; |
| typedef SimpleRegistryEntry<T> entry; |
| |
| class node; |
| class iterator; |
| |
| private: |
| Registry() = delete; |
| |
| friend class node; |
| static node *Head, *Tail; |
| |
| public: |
| /// Node in linked list of entries. |
| /// |
| class node { |
| friend class iterator; |
| friend Registry<T>; |
| |
| node *Next; |
| const entry& Val; |
| |
| public: |
| node(const entry &V) : Next(nullptr), Val(V) {} |
| }; |
| |
| /// Add a node to the Registry: this is the interface between the plugin and |
| /// the executable. |
| /// |
| /// This function is exported by the executable and called by the plugin to |
| /// add a node to the executable's registry. Therefore it's not defined here |
| /// to avoid it being instantiated in the plugin and is instead defined in |
| /// the executable (see LLVM_INSTANTIATE_REGISTRY below). |
| static void add_node(node *N); |
| |
| /// Iterators for registry entries. |
| /// |
| class iterator { |
| const node *Cur; |
| |
| public: |
| explicit iterator(const node *N) : Cur(N) {} |
| |
| bool operator==(const iterator &That) const { return Cur == That.Cur; } |
| bool operator!=(const iterator &That) const { return Cur != That.Cur; } |
| iterator &operator++() { Cur = Cur->Next; return *this; } |
| const entry &operator*() const { return Cur->Val; } |
| const entry *operator->() const { return &Cur->Val; } |
| }; |
| |
| // begin is not defined here in order to avoid usage of an undefined static |
| // data member, instead it's instantiated by LLVM_INSTANTIATE_REGISTRY. |
| static iterator begin(); |
| static iterator end() { return iterator(nullptr); } |
| |
| static iterator_range<iterator> entries() { |
| return make_range(begin(), end()); |
| } |
| |
| /// A static registration template. Use like such: |
| /// |
| /// Registry<Collector>::Add<FancyGC> |
| /// X("fancy-gc", "Newfangled garbage collector."); |
| /// |
| /// Use of this template requires that: |
| /// |
| /// 1. The registered subclass has a default constructor. |
| template <typename V> |
| class Add { |
| entry Entry; |
| node Node; |
| |
| static std::unique_ptr<T> CtorFn() { return make_unique<V>(); } |
| |
| public: |
| Add(StringRef Name, StringRef Desc) |
| : Entry(Name, Desc, CtorFn), Node(Entry) { |
| add_node(&Node); |
| } |
| }; |
| }; |
| } // end namespace llvm |
| |
| /// Instantiate a registry class. |
| /// |
| /// This provides template definitions of add_node, begin, and the Head and Tail |
| /// pointers, then explicitly instantiates them. We could explicitly specialize |
| /// them, instead of the two-step process of define then instantiate, but |
| /// strictly speaking that's not allowed by the C++ standard (we would need to |
| /// have explicit specialization declarations in all translation units where the |
| /// specialization is used) so we don't. |
| #define LLVM_INSTANTIATE_REGISTRY(REGISTRY_CLASS) \ |
| namespace llvm { \ |
| template<typename T> typename Registry<T>::node *Registry<T>::Head = nullptr;\ |
| template<typename T> typename Registry<T>::node *Registry<T>::Tail = nullptr;\ |
| template<typename T> \ |
| void Registry<T>::add_node(typename Registry<T>::node *N) { \ |
| if (Tail) \ |
| Tail->Next = N; \ |
| else \ |
| Head = N; \ |
| Tail = N; \ |
| } \ |
| template<typename T> typename Registry<T>::iterator Registry<T>::begin() { \ |
| return iterator(Head); \ |
| } \ |
| template REGISTRY_CLASS::node *Registry<REGISTRY_CLASS::type>::Head; \ |
| template REGISTRY_CLASS::node *Registry<REGISTRY_CLASS::type>::Tail; \ |
| template \ |
| void Registry<REGISTRY_CLASS::type>::add_node(REGISTRY_CLASS::node*); \ |
| template REGISTRY_CLASS::iterator Registry<REGISTRY_CLASS::type>::begin(); \ |
| } |
| |
| #endif // LLVM_SUPPORT_REGISTRY_H |