[Macros] Track loaded plugin paths in each ASTContext

PluginRegistry is now shared between multiple ASTContext. ASTContext
should track its loaded plugin library paths separately.

Author: rintaro

include/swift/AST/ASTContext.h

@@ -1503,6 +1503,8 @@ class ASTContext final {
   /// This should be called before any plugin is loaded.
   void setPluginRegistry(PluginRegistry *newValue);
 
+  const llvm::StringSet<> &getLoadedPluginLibraryPaths() const;
+
 private:
   friend Decl;
 

include/swift/AST/PluginRegistry.h

@@ -152,10 +152,6 @@ class PluginRegistry {
   /// If \p path plugin is already loaded, this returns the cached object.
   llvm::Expected<LoadedExecutablePlugin *>
   loadExecutablePlugin(llvm::StringRef path);
-
-  const llvm::StringMap<void *> &getLoadedLibraryPlugins() const {
-    return LoadedPluginLibraries;
-  }
 };
 
 } // namespace swift

lib/AST/ASTContext.cpp

@@ -534,6 +534,8 @@ struct ASTContext::Implementation {
   /// Map a module name to an executable plugin path that provides the module.
   llvm::DenseMap<Identifier, StringRef> ExecutablePluginPaths;
 
+  llvm::StringSet<> LoadedPluginLibraryPaths;
+
   /// The permanent arena.
   Arena Permanent;
 
@@ -6395,6 +6397,9 @@ LoadedExecutablePlugin *ASTContext::loadExecutablePlugin(StringRef path) {
 }
 
 void *ASTContext::loadLibraryPlugin(StringRef path) {
+  // Remember the path (even if it fails to load.)
+  getImpl().LoadedPluginLibraryPaths.insert(path);
+
   SmallString<128> resolvedPath;
   auto fs = this->SourceMgr.getFileSystem();
   if (auto err = fs->getRealPath(path, resolvedPath)) {
@@ -6413,6 +6418,10 @@ void *ASTContext::loadLibraryPlugin(StringRef path) {
   return plugin.get();
 }
 
+const llvm::StringSet<> &ASTContext::getLoadedPluginLibraryPaths() const {
+  return getImpl().LoadedPluginLibraryPaths;
+}
+
 bool ASTContext::supportsMoveOnlyTypes() const {
   // currently the only thing holding back whether the types can appear is this.
   return SILOpts.LexicalLifetimes != LexicalLifetimesOption::Off;

lib/FrontendTool/LoadedModuleTrace.cpp

@@ -760,8 +760,7 @@ bool swift::emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
   }
 
   // Add compiler plugin libraries as dependencies.
-  auto *pluginRegistry = ctxt.getPluginRegistry();
-  for (auto &pluginEntry : pluginRegistry->getLoadedLibraryPlugins())
+  for (auto &pluginEntry : ctxt.getLoadedPluginLibraryPaths())
     depTracker->addDependency(pluginEntry.getKey(), /*IsSystem*/ false);
 
   std::vector<SwiftModuleTraceInfo> swiftModules;