Adjust Registry interface to not require plugins to export a registry

john-brawn-arm · john-brawn-arm · commit 63aff61019e0 · 2016-07-27T11:18:38.000Z
Currently the Registry class contains the vestiges of a previous attempt to allow plugins to be used on Windows without using BUILD_SHARED_LIBS, where a plugin would have its own copy of a registry and export it to be imported by the tool that's loading the plugin. This only works if the plugin is entirely self-contained with the only interface between the plugin and tool being the registry, and in particular this conflicts with how IR pass plugins work. This patch changes things so that instead the add_node function of the registry is exported by the tool and then imported by the plugin, which solves this problem and also means that instead of every plugin having to export every registry they use instead LLVM only has to export the add_node functions. This allows plugins that use a registry to work on Windows if LLVM_EXPORT_SYMBOLS_FOR_PLUGINS is used. Differential Revision: http://reviews.llvm.org/D21385 llvm-svn: 276856
diff --git a/clang/examples/AnnotateFunctions/CMakeLists.txt b/clang/examples/AnnotateFunctions/CMakeLists.txt
@@ -1,4 +1,4 @@
-add_llvm_loadable_module(AnnotateFunctions AnnotateFunctions.cpp)
+add_llvm_loadable_module(AnnotateFunctions AnnotateFunctions.cpp PLUGIN_TOOL clang)
 
 if(LLVM_ENABLE_PLUGINS AND (WIN32 OR CYGWIN))
   target_link_libraries(AnnotateFunctions PRIVATE
diff --git a/clang/examples/PrintFunctionNames/CMakeLists.txt b/clang/examples/PrintFunctionNames/CMakeLists.txt
@@ -9,7 +9,7 @@ if( NOT MSVC ) # MSVC mangles symbols differently, and
   endif()
 endif()
 
-add_llvm_loadable_module(PrintFunctionNames PrintFunctionNames.cpp)
+add_llvm_loadable_module(PrintFunctionNames PrintFunctionNames.cpp PLUGIN_TOOL clang)
 
 if(LLVM_ENABLE_PLUGINS AND (WIN32 OR CYGWIN))
   target_link_libraries(PrintFunctionNames PRIVATE
diff --git a/clang/include/clang/Frontend/FrontendPluginRegistry.h b/clang/include/clang/Frontend/FrontendPluginRegistry.h
@@ -13,9 +13,6 @@
 #include "clang/Frontend/FrontendAction.h"
 #include "llvm/Support/Registry.h"
 
-// Instantiated in FrontendAction.cpp.
-extern template class llvm::Registry<clang::PluginASTAction>;
-
 namespace clang {
 
 /// The frontend plugin registry.
diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
@@ -1956,6 +1956,4 @@ typedef llvm::Registry<PragmaHandler> PragmaHandlerRegistry;
 
 }  // end namespace clang
 
-extern template class llvm::Registry<clang::PragmaHandler>;
-
 #endif
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
@@ -33,7 +33,7 @@
 #include <system_error>
 using namespace clang;
 
-template class llvm::Registry<clang::PluginASTAction>;
+LLVM_INSTANTIATE_REGISTRY(FrontendPluginRegistry)
 
 namespace {
 
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
@@ -54,7 +54,7 @@
 #include <utility>
 using namespace clang;
 
-template class llvm::Registry<clang::PragmaHandler>;
+LLVM_INSTANTIATE_REGISTRY(PragmaHandlerRegistry)
 
 //===----------------------------------------------------------------------===//
 ExternalPreprocessorSource::~ExternalPreprocessorSource() { }
diff --git a/clang/lib/Tooling/CompilationDatabase.cpp b/clang/lib/Tooling/CompilationDatabase.cpp
@@ -32,6 +32,8 @@
 using namespace clang;
 using namespace tooling;
 
+LLVM_INSTANTIATE_REGISTRY(CompilationDatabasePluginRegistry)
+
 CompilationDatabase::~CompilationDatabase() {}
 
 std::unique_ptr<CompilationDatabase>
diff --git a/llvm/include/llvm/Support/Registry.h b/llvm/include/llvm/Support/Registry.h
@@ -69,13 +69,14 @@ namespace llvm {
       node(const entry &V) : Next(nullptr), Val(V) {}
     };
 
-    static void add_node(node *N) {
-      if (Tail)
-        Tail->Next = N;
-      else
-        Head = N;
-      Tail = N;
-    }
+    /// 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.
     ///
@@ -120,61 +121,23 @@ namespace llvm {
         add_node(&Node);
       }
     };
-
-    /// A dynamic import facility.  This is used on Windows to
-    /// import the entries added in the plugin.
-    static void import(sys::DynamicLibrary &DL, const char *RegistryName) {
-      typedef void *(*GetRegistry)();
-      std::string Name("LLVMGetRegistry_");
-      Name.append(RegistryName);
-      GetRegistry Getter =
-          (GetRegistry)(intptr_t)DL.getAddressOfSymbol(Name.c_str());
-      if (Getter) {
-        // Call the getter function in order to get the full copy of the
-        // registry defined in the plugin DLL, and copy them over to the
-        // current Registry.
-        typedef std::pair<const node *, const node *> Info;
-        Info *I = static_cast<Info *>(Getter());
-        iterator begin(I->first);
-        iterator end(I->second);
-        for (++end; begin != end; ++begin) {
-          // This Node object needs to remain alive for the
-          // duration of the program.
-          add_node(new node(*begin));
-        }
-      }
-    }
-
-    /// Retrieve the data to be passed across DLL boundaries when
-    /// importing registries from another DLL on Windows.
-    static void *exportRegistry() {
-      static std::pair<const node *, const node *> Info(Head, Tail);
-      return &Info;
-    }
   };
-
-  
-  // Since these are defined in a header file, plugins must be sure to export
-  // these symbols.
-  template <typename T>
-  typename Registry<T>::node *Registry<T>::Head;
-
-  template <typename T>
-  typename Registry<T>::node *Registry<T>::Tail;
 } // end namespace llvm
 
-#ifdef LLVM_ON_WIN32
-#define LLVM_EXPORT_REGISTRY(REGISTRY_CLASS)                                   \
-  extern "C" {                                                                 \
-  __declspec(dllexport) void *__cdecl LLVMGetRegistry_##REGISTRY_CLASS() {     \
-    return REGISTRY_CLASS::exportRegistry();                                   \
-  }                                                                            \
+/// Instantiate a registry class.
+///
+/// This instantiates add_node and the Head and Tail pointers.
+#define LLVM_INSTANTIATE_REGISTRY(REGISTRY_CLASS) \
+  namespace llvm { \
+  template<> void REGISTRY_CLASS::add_node(REGISTRY_CLASS::node *N) { \
+    if (Tail) \
+     Tail->Next = N; \
+    else \
+      Head = N; \
+    Tail = N; \
+  } \
+  template<> typename REGISTRY_CLASS::node *REGISTRY_CLASS::Head = nullptr; \
+  template<> typename REGISTRY_CLASS::node *REGISTRY_CLASS::Tail = nullptr; \
   }
-#define LLVM_IMPORT_REGISTRY(REGISTRY_CLASS, DL)                               \
-  REGISTRY_CLASS::import(DL, #REGISTRY_CLASS)
-#else
-#define LLVM_EXPORT_REGISTRY(REGISTRY_CLASS)
-#define LLVM_IMPORT_REGISTRY(REGISTRY_CLASS, DL)
-#endif
 
 #endif // LLVM_SUPPORT_REGISTRY_H
diff --git a/llvm/lib/CodeGen/GCMetadataPrinter.cpp b/llvm/lib/CodeGen/GCMetadataPrinter.cpp
@@ -14,6 +14,8 @@
 #include "llvm/CodeGen/GCMetadataPrinter.h"
 using namespace llvm;
 
+LLVM_INSTANTIATE_REGISTRY(GCMetadataPrinterRegistry)
+
 GCMetadataPrinter::GCMetadataPrinter() {}
 
 GCMetadataPrinter::~GCMetadataPrinter() {}
diff --git a/llvm/lib/CodeGen/GCStrategy.cpp b/llvm/lib/CodeGen/GCStrategy.cpp
@@ -16,6 +16,8 @@
 
 using namespace llvm;
 
+LLVM_INSTANTIATE_REGISTRY(GCRegistry)
+
 GCStrategy::GCStrategy()
     : UseStatepoints(false), NeededSafePoints(0), CustomReadBarriers(false),
       CustomWriteBarriers(false), CustomRoots(false), InitRoots(true),

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-add_llvm_loadable_module(AnnotateFunctions AnnotateFunctions.cpp)`
	`1`	`+add_llvm_loadable_module(AnnotateFunctions AnnotateFunctions.cpp PLUGIN_TOOL clang)`
`2`	`2`
`3`	`3`	`if(LLVM_ENABLE_PLUGINS AND (WIN32 OR CYGWIN))`
`4`	`4`	`target_link_libraries(AnnotateFunctions PRIVATE`