llvm.org GIT mirror llvm / 9ed0c7a include / llvm / Support / Registry.h
9ed0c7a

Tree @9ed0c7a (Download .tar.gz)

Registry.h @9ed0c7a

d9900c9
 
 
 
7ed47a1
 
d9900c9
 
 
 
5c1799b
d9900c9
 
 
 
 
9c94042
c5aa287
9159781
f00e9ae
9159781
9c94042
 
d9900c9
 
 
 
 
a8904db
9c94042
5c1799b
d9900c9
a8904db
 
5c1799b
a8904db
 
9c94042
d9900c9
5c1799b
d9900c9
 
 
103a361
d9900c9
 
eca7f45
103a361
5c1799b
d9900c9
 
5c1799b
d9900c9
66981fe
5c1799b
d9900c9
 
5c1799b
d9900c9
 
5c1799b
d9900c9
 
9159781
5c1799b
d9900c9
 
5c1799b
d9900c9
9159781
d9900c9
5c1799b
eca7f45
 
 
 
 
 
 
 
9159781
d9900c9
5c1799b
d9900c9
 
5c1799b
d9900c9
 
5c1799b
d9900c9
 
 
 
 
 
5c1799b
eca7f45
 
 
4ba8443
5c1799b
07fbc5c
e6bc7d1
07fbc5c
 
d9900c9
5c1799b
d9900c9
 
5c1799b
d9900c9
5c1799b
d9900c9
 
 
 
 
5c1799b
9c94042
5c1799b
d9900c9
a8904db
9159781
 
 
d9900c9
 
d16725c
d9900c9
eca7f45
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
14f1319
eca7f45
 
9159781
 
d16725c
//=== 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