[SourceKit] Add mechanism to load plugins for request handling into SourceKit

This allows us to load plugins into the sourcekitd service to handle requests (currently only used for code completion). This allows us to implement parts of sourcekitd in Swift and outside of the compiler repository, making it easier to iterated on them because the compiler doesn’t need to be rebuilt.

Author: ahoppen

tools/SourceKit/include/SourceKit/Core/Context.h

@@ -31,6 +31,7 @@ namespace llvm {
 namespace SourceKit {
   class LangSupport;
   class NotificationCenter;
+  class PluginSupport;
 
 class GlobalConfig {
 public:
@@ -169,13 +170,16 @@ class Context {
   std::shared_ptr<NotificationCenter> NotificationCtr;
   std::shared_ptr<GlobalConfig> Config;
   std::shared_ptr<RequestTracker> ReqTracker;
+  std::shared_ptr<PluginSupport> Plugins;
   std::shared_ptr<SlowRequestSimulator> SlowRequestSim;
 
 public:
   Context(StringRef SwiftExecutablePath, StringRef RuntimeLibPath,
           StringRef DiagnosticDocumentationPath,
           llvm::function_ref<std::unique_ptr<LangSupport>(Context &)>
               LangSupportFactoryFn,
+          llvm::function_ref<std::shared_ptr<PluginSupport>(Context &)>
+              PluginSupportFactoryFn,
           bool shouldDispatchNotificationsOnMain = true);
   ~Context();
 
@@ -192,6 +196,8 @@ class Context {
 
   std::shared_ptr<GlobalConfig> getGlobalConfiguration() { return Config; }
 
+  std::shared_ptr<PluginSupport> getPlugins() { return Plugins; }
+
   std::shared_ptr<SlowRequestSimulator> getSlowRequestSimulator() {
     return SlowRequestSim;
   }

tools/SourceKit/include/SourceKit/Core/LangSupport.h

@@ -1024,6 +1024,8 @@ class LangSupport {
 
   virtual ~LangSupport() { }
 
+  virtual void *getOpaqueSwiftIDEInspectionInstance() { return nullptr; }
+
   virtual void globalConfigurationUpdated(std::shared_ptr<GlobalConfig> Config) {};
 
   virtual void dependencyUpdated() {}

tools/SourceKit/lib/Core/Context.cpp

@@ -40,6 +40,8 @@ SourceKit::Context::Context(
     StringRef DiagnosticDocumentationPath,
     llvm::function_ref<std::unique_ptr<LangSupport>(Context &)>
         LangSupportFactoryFn,
+    llvm::function_ref<std::shared_ptr<PluginSupport>(Context &)>
+        PluginSupportFactoryFn,
     bool shouldDispatchNotificationsOnMain)
     : SwiftExecutablePath(SwiftExecutablePath), RuntimeLibPath(RuntimeLibPath),
       DiagnosticDocumentationPath(DiagnosticDocumentationPath),
@@ -49,6 +51,7 @@ SourceKit::Context::Context(
       SlowRequestSim(new SlowRequestSimulator(ReqTracker)) {
   // Should be called last after everything is initialized.
   SwiftLang = LangSupportFactoryFn(*this);
+  Plugins = PluginSupportFactoryFn(*this);
 }
 
 SourceKit::Context::~Context() {

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h

@@ -534,6 +534,10 @@ class SwiftLangSupport : public LangSupport {
   // LangSupport Interface
   //==========================================================================//
 
+  void *getOpaqueSwiftIDEInspectionInstance() override {
+    return IDEInspectionInst.get();
+  }
+
   void globalConfigurationUpdated(std::shared_ptr<GlobalConfig> Config) override;
 
   void dependencyUpdated() override;

tools/SourceKit/tools/sourcekitd/bin/InProc/CMakeLists.txt

@@ -11,13 +11,16 @@ swift_is_installing_component(sourcekit-inproc SOURCEKIT_INSTALLING_INPROC)
 
 set(sourcekitdInProc_args
   sourcekitdInProc.cpp
+  CodeCompletionSwiftInterop.cpp
   LLVM_LINK_COMPONENTS support coverage
 )
 
 if (SOURCEKIT_INSTALLING_INPROC)
   if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
     add_sourcekit_framework(sourcekitdInProc
       ${SOURCEKITD_SOURCE_DIR}/include/sourcekitd/sourcekitd.h
+      ${SOURCEKITD_SOURCE_DIR}/include/sourcekitd/plugin.h
+      ${CMAKE_CURRENT_SOURCE_DIR}/CodeCompletionSwiftInterop.h
       ${sourcekitdInProc_args}
       MODULEMAP module.modulemap
       INSTALL_IN_COMPONENT sourcekit-inproc