My previous Registry.h header, as well as Collectors.h, which is the

registry for dynamically-loaded garbage collection compiler plugins.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42415 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/Collectors.h

@@ -0,0 +1,36 @@
+//===-- Collectors.h - Garbage collector registry -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Gordon Henriksen and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the CollectorRegistry class, which is used to discover
+// pluggable garbage collectors.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_COLLECTORS_H
+#define LLVM_CODEGEN_COLLECTORS_H
+
+#include "llvm/Support/Registry.h"
+
+namespace llvm {
+
+  class Collector;
+  
+  /// The collector registry uses all the defaults from Registry.
+  /// 
+  typedef Registry<Collector> CollectorRegistry;
+  
+  /// Creates an ocaml-compatible garbage collector.
+  Collector *createOcamlCollector();
+  
+  /// Creates a shadow stack garbage collector. This collector requires no code
+  /// generator support.
+  Collector *createShadowStackCollector();
+}
+
+#endif

include/llvm/Support/Registry.h

@@ -0,0 +1,243 @@
+//=== Registry.h - Linker-supported plugin registries -----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Gordon Henriksen and 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/Support/CommandLine.h"
+
+namespace llvm {
+  /// A simple registry entry which provides only a name, description, and
+  /// no-argument constructor.
+  template <typename T>
+  class SimpleRegistryEntry {
+    const char *Name, *Desc;
+    T *(*Ctor)();
+    
+  public:
+    SimpleRegistryEntry(const char *N, const char *D, T *(*C)())
+      : Name(N), Desc(D), Ctor(C)
+    {}
+    
+    const char *getName() const { return Name; }
+    const char *getDesc() const { return Desc; }
+    T *instantiate() const { return Ctor(); }
+  };
+  
+  
+  /// Traits for registry entries. If using other than SimpleRegistryEntry, it
+  /// is necessary to define an alternate traits class.
+  template <typename T>
+  class RegistryTraits {
+    RegistryTraits(); // Do not implement.
+    
+  public:
+    typedef SimpleRegistryEntry<T> entry;
+    
+    /// Accessors for .
+    /// 
+    static const char *nameof(const entry &Entry) { return Entry.getName(); }
+    static const char *descof(const entry &Entry) { return Entry.getDesc(); }
+  };
+  
+  
+  /// 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, typename U = RegistryTraits<T> >
+  class Registry {
+  public:
+    typedef U traits;
+    typedef typename U::entry entry;
+    
+    class node;
+    class listener;
+    class iterator;
+  
+  private:
+    Registry(); // Do not implement.
+    
+    static void Announce(node *);
+    
+    friend class node;
+    static node *Head, *Tail;
+    
+    friend class listener;
+    static listener *ListenerHead, *ListenerTail;
+    
+  public:
+    class iterator;
+    
+    
+    /// Node in linked list of entries.
+    /// 
+    class node {
+      friend class iterator;
+      
+      node *Next;
+      const entry& Val;
+      
+    public:
+      node(const entry& V) : Next(0), Val(V) {
+        if (Tail)
+          Tail->Next = this;
+        else
+          Head = this;
+        Tail = this;
+        
+        Announce(V);
+      }
+    };
+    
+    
+    /// 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; }
+    };
+    
+    static iterator begin() { return iterator(Head); }
+    static iterator end()   { return iterator(0); }
+    
+    
+    /// Abstract base class for registry listeners, which are informed when new
+    /// entries are added to the registry. Simply subclass and instantiate:
+    /// 
+    ///   class CollectorPrinter : public Registry<Collector>::listener {
+    ///   protected:
+    ///     void registered(const Registry<Collector>::entry &e) {
+    ///       cerr << "collector now available: " << e->getName() << "\n";
+    ///     }
+    ///   
+    ///   public:
+    ///     CollectorPrinter() { init(); }  // Print those already registered.
+    ///   };
+    /// 
+    ///   CollectorPrinter Printer;
+    /// 
+    class listener {
+      listener *Prev, *Next;
+      
+      friend void Registry::Announce(const entry &E);
+      
+    protected:
+      /// Called when an entry is added to the registry.
+      /// 
+      virtual void registered(const entry &) = 0;
+      
+      /// Calls 'registered' for each pre-existing entry.
+      /// 
+      void init() {
+        for (iterator I = begin(), E = end(); I != E; ++I)
+          registered(*I);
+      }
+      
+    public:
+      listener() : Prev(ListenerTail), Next(0) {
+        if (Prev)
+          Prev->Next = this;
+        else
+          ListenerHead = this;
+        ListenerTail = this;
+      }
+      
+      virtual ~listener() {
+        if (Next)
+          Next->Prev = Prev;
+        else
+          ListenerTail = Prev;
+        if (Prev)
+          Prev->Next = Next;
+        else
+          ListenerHead = Next;
+      }
+    };
+    
+    
+    /// 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.
+    // 
+    ///  2. The registry entry type has a constructor compatible with this
+    ///     signature:
+    /// 
+    ///       entry(const char *Name, const char *ShortDesc, T *(*Ctor)());
+    /// 
+    /// If you have more elaborate requirements, then copy and modify.
+    /// 
+    template <typename V>
+    class Add {
+      entry Entry;
+      node Node;
+      
+      static T *CtorFn() { return new V(); }
+      
+    public:
+      Add(const char *Name, const char *Desc)
+        : Entry(Name, Desc, CtorFn), Node(Entry) {}
+    };
+    
+    
+    /// A command-line parser for a registry. Use like such:
+    /// 
+    ///   static cl::opt<Registry<Collector>::entry, false,
+    ///                  Registry<Collector>::Parser>
+    ///   GCOpt("gc", cl::desc("Garbage collector to use."),
+    ///               cl::value_desc());
+    ///   
+    /// To make use of the value:
+    /// 
+    ///   Collector *TheCollector = GCOpt->instantiate();
+    /// 
+    class Parser : public cl::parser<const typename U::entry*>, public listener{
+      typedef U traits;
+      typedef typename U::entry entry;
+      
+    protected:
+      void registered(const entry &E) {
+        addLiteralOption(traits::nameof(E), &E, traits::descof(E));
+      }
+      
+    public:
+      void initialize(cl::Option &O) {
+        listener::init();
+        cl::parser<const typename U::entry*>::initialize(O);
+      }
+    };
+    
+    
+  private:
+    static void Announce(const entry &E) {
+      for (listener *Cur = ListenerHead; Cur; Cur = Cur->Next)
+        Cur->registered(E);
+    }
+    
+  };
+  
+}
+
+#endif

lib/CodeGen/Collectors.cpp

@@ -0,0 +1,21 @@
+//===-- Collectors.cpp - Garbage collector registry -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Gordon Henriksen and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the static data members of the CollectorRegistry class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/Collectors.h"
+
+using namespace llvm;
+
+template<> CollectorRegistry::node *CollectorRegistry::Head = 0;
+template<> CollectorRegistry::node *CollectorRegistry::Tail = 0;
+template<> CollectorRegistry::listener *CollectorRegistry::ListenerHead = 0;
+template<> CollectorRegistry::listener *CollectorRegistry::ListenerTail = 0;