[PATCH] D16761: clang-cl: Support loading plugins on Windows

[Ehsan Akhgari via cfe-commits]

ehsan created this revision.
ehsan added a reviewer: rnk.
ehsan added a subscriber: cfe-commits.

This builds on the support being added to LLVM to import and export
registries from DLLs.  This will allow us to pick up the registry
entries added in the DLL's copy of FrontendPluginRegistry.

This will allow us to use plugins on Windows using:
$ clang-cl -Xclang -load -Xclang plugin.dll \
           -Xclang -add-plugin -Xclang foo

clang-cl: Enable plugins on Windows

http://reviews.llvm.org/D16761

Files:
  docs/ClangPlugins.rst
  examples/PrintFunctionNames/PrintFunctionNames.cpp
  lib/FrontendTool/ExecuteCompilerInvocation.cpp
  test/Frontend/plugins.c
  test/lit.cfg

Index: test/lit.cfg
===================================================================
--- test/lit.cfg
+++ test/lit.cfg
@@ -196,7 +196,7 @@
 
 # Plugins (loadable modules)
 # TODO: This should be supplied by Makefile or autoconf.
-if sys.platform in ['win32', 'cygwin']:
+if sys.platform in ['cygwin']:
     has_plugins = (config.enable_shared == 1)
 else:
     has_plugins = True
Index: test/Frontend/plugins.c
===================================================================
--- test/Frontend/plugins.c
+++ test/Frontend/plugins.c
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -load %llvmshlibdir/PrintFunctionNames%pluginext -plugin print-fns %s 2>&1 | FileCheck %s
+// RUN: %clang_cl -Xclang -load -Xclang %llvmshlibdir/PrintFunctionNames%pluginext -Xclang -plugin -Xclang print-fns %s 2>&1 | FileCheck %s
 // REQUIRES: plugins, examples
 
 // CHECK: top-level-decl: "x"
Index: lib/FrontendTool/ExecuteCompilerInvocation.cpp
===================================================================
--- lib/FrontendTool/ExecuteCompilerInvocation.cpp
+++ lib/FrontendTool/ExecuteCompilerInvocation.cpp
@@ -184,9 +184,18 @@
          e = Clang->getFrontendOpts().Plugins.size(); i != e; ++i) {
     const std::string &Path = Clang->getFrontendOpts().Plugins[i];
     std::string Error;
-    if (llvm::sys::DynamicLibrary::LoadLibraryPermanently(Path.c_str(), &Error))
+    llvm::sys::DynamicLibrary DL(
+        llvm::sys::DynamicLibrary::getPermanentLibrary(Path.c_str(), &Error));
+    if (DL.isValid()) {
+#ifdef _MSC_VER
+      // On Windows, we need to import the plugin front-end action
+      // dynamically.
+      LLVM_IMPORT_REGISTRY(FrontendPluginRegistry, DL);
+#endif
+    } else {
       Clang->getDiagnostics().Report(diag::err_fe_unable_to_load_plugin)
         << Path << Error;
+    }
   }
 
   // Honor -mllvm.
Index: examples/PrintFunctionNames/PrintFunctionNames.cpp
===================================================================
--- examples/PrintFunctionNames/PrintFunctionNames.cpp
+++ examples/PrintFunctionNames/PrintFunctionNames.cpp
@@ -121,3 +121,6 @@
 
 static FrontendPluginRegistry::Add<PrintFunctionNamesAction>
 X("print-fns", "print function names");
+#ifdef _MSC_VER
+LLVM_EXPORT_REGISTRY(FrontendPluginRegistry)
+#endif
Index: docs/ClangPlugins.rst
===================================================================
--- docs/ClangPlugins.rst
+++ docs/ClangPlugins.rst
@@ -37,11 +37,16 @@
 ====================
 
 A plugin is loaded from a dynamic library at runtime by the compiler. To
-register a plugin in a library, use ``FrontendPluginRegistry::Add<>``:
+register a plugin in a library, use ``FrontendPluginRegistry::Add<>``.
+Note that on Windows, you also need to export your plugin registry using
+``LLVM_EXPORT_REGISTRY``.  Here is an example:
 
 .. code-block:: c++
 
   static FrontendPluginRegistry::Add<MyPlugin> X("my-plugin-name", "my plugin description");
+  #ifdef _MSC_VER
+  LLVM_EXPORT_REGISTRY(FrontendPluginRegistry)
+  #endif
 
 Putting it all together
 =======================


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