[Macros] Use 'LibraryPluginProvider' in swift-plugin-server

Move 'PluginProvider' logic to 'SwiftLibraryPluginProvider' module
so the compiler can reuse that logic for the actual in-process plugins.

(cherry picked from commit 26dbe2f)

Author: rintaro

test/Macros/macro_plugin_server.swift

@@ -87,7 +87,7 @@ func testStringify(a: Int, b: Int) {
   let s3: String = #stringify(b + a).1
   print(s3)
 
-  // expected-error @+1 {{macro implementation type 'MacroDefinition.TypeDoesNotExist' could not be found in library plugin '}}
+  // expected-error @+1 {{type 'MacroDefinition.TypeDoesNotExist' could not be found in library plugin '}}
   _ = #missing()
 
   // expected-error @+1 {{type 'MacroDefinition.NotMacroStruct' is not a valid macro implementation type in library plugin '}}

tools/swift-plugin-server/CMakeLists.txt

@@ -1,29 +1,10 @@
 if (SWIFT_BUILD_SWIFT_SYNTAX)
-  # _swiftCSwiftPluginServer is just a C support library for swift-plugin-server
-  # Don't bother to create '.a' for that.
-  add_swift_host_library(_swiftCSwiftPluginServer STATIC
-    Sources/CSwiftPluginServer/PluginServer.cpp
-    LLVM_LINK_COMPONENTS support
-  )
-  target_link_libraries(_swiftCSwiftPluginServer PRIVATE
-    swiftDemangling
-  )
-  target_include_directories(_swiftCSwiftPluginServer PUBLIC
-    Sources/CSwiftPluginServer/include
-  )
-
   add_pure_swift_host_tool(swift-plugin-server
     Sources/swift-plugin-server/swift-plugin-server.swift
-    DEPENDENCIES
-      _swiftCSwiftPluginServer
     SWIFT_COMPONENT
       compiler
     SWIFT_DEPENDENCIES
-      SwiftSyntaxMacros
-      SwiftSyntaxMacroExpansion
       SwiftCompilerPluginMessageHandling
-  )
-  target_include_directories(swift-plugin-server PRIVATE
-    Sources/CSwiftPluginServer/include
+      SwiftLibraryPluginProvider
   )
 endif()

tools/swift-plugin-server/Package.swift

@@ -11,25 +11,10 @@ let package = Package(
     .package(path: "../../../swift-syntax"),
   ],
   targets: [
-    .target(
-      name: "CSwiftPluginServer",
-      cxxSettings: [
-        .unsafeFlags([
-          "-I", "../../include",
-          "-I", "../../../llvm-project/llvm/include",
-        ])
-      ]
-    ),
     .executableTarget(
       name: "swift-plugin-server",
       dependencies: [
         .product(name: "SwiftCompilerPluginMessageHandling", package: "swift-syntax"),
-        .product(name: "SwiftDiagnostics", package: "swift-syntax"),
-        .product(name: "SwiftSyntax", package: "swift-syntax"),
-        .product(name: "SwiftOperators", package: "swift-syntax"),
-        .product(name: "SwiftParser", package: "swift-syntax"),
-        .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
-        "CSwiftPluginServer"
       ]
     ),
   ],

tools/swift-plugin-server/Sources/CSwiftPluginServer/PluginServer.cpp

@@ -11,96 +11,16 @@
 //===----------------------------------------------------------------------===//
 
 @_spi(PluginMessage) import SwiftCompilerPluginMessageHandling
-import SwiftSyntaxMacros
-import CSwiftPluginServer
+@_spi(PluginMessage) import SwiftLibraryPluginProvider
 
 @main
 final class SwiftPluginServer {
-  struct MacroRef: Hashable {
-    var moduleName: String
-    var typeName: String
-    init(_ moduleName: String, _ typeName: String) {
-      self.moduleName = moduleName
-      self.typeName = typeName
-    }
-  }
-
-  struct LoadedLibraryPlugin {
-    var libraryPath: String
-    var handle: UnsafeMutableRawPointer
-  }
-
-  /// Loaded dylib handles associated with the module name.
-  var loadedLibraryPlugins: [String: LoadedLibraryPlugin] = [:]
-
-  /// Resolved cached macros.
-  var resolvedMacros: [MacroRef: Macro.Type] = [:]
-
-  /// @main entry point.
   static func main() throws {
     let connection = try StandardIOMessageConnection()
     let listener = CompilerPluginMessageListener(
       connection: connection,
-      provider: self.init()
+      provider: LibraryPluginProvider.shared
     )
-    try listener.main()
-  }
-}
-
-extension SwiftPluginServer: PluginProvider {
-  /// Load a macro implementation from the dynamic link library.
-  func loadPluginLibrary(libraryPath: String, moduleName: String) throws {
-    var errorMessage: UnsafePointer<CChar>?
-    guard let dlHandle = PluginServer_load(libraryPath, &errorMessage) else {
-      throw PluginServerError(message: "loader error: " + String(cString: errorMessage!))
-    }
-    loadedLibraryPlugins[moduleName] = LoadedLibraryPlugin(
-      libraryPath: libraryPath,
-      handle: dlHandle
-    )
-  }
-
-  /// Lookup a loaded macro by a pair of module name and type name.
-  func resolveMacro(moduleName: String, typeName: String) throws -> Macro.Type {
-    if let resolved = resolvedMacros[.init(moduleName, typeName)] {
-      return resolved
-    }
-
-    // Find 'dlopen'ed library for the module name.
-    guard let plugin = loadedLibraryPlugins[moduleName] else {
-      // NOTE: This should be unreachable. Compiler should not use this server
-      // unless the plugin loading succeeded.
-      throw PluginServerError(message: "(plugin-server) plugin not loaded for module '\(moduleName)'")
-    }
-
-    // Lookup the type metadata.
-    var errorMessage: UnsafePointer<CChar>?
-    guard let macroTypePtr = PluginServer_lookupMacroTypeMetadataByExternalName(
-      moduleName, typeName, plugin.handle, &errorMessage
-    ) else {
-      throw PluginServerError(message: "macro implementation type '\(moduleName).\(typeName)' could not be found in library plugin '\(plugin.libraryPath)'")
-    }
-
-    // THe type must be a 'Macro' type.
-    let macroType = unsafeBitCast(macroTypePtr, to: Any.Type.self)
-    guard let macro = macroType as? Macro.Type else {
-      throw PluginServerError(message: "type '\(moduleName).\(typeName)' is not a valid macro implementation type in library plugin '\(plugin.libraryPath)'")
-    }
-
-    // Cache the resolved type.
-    resolvedMacros[.init(moduleName, typeName)] = macro
-    return macro
-  }
-
-  /// This 'PluginProvider' implements 'loadLibraryMacro()'.
-  var features: [SwiftCompilerPluginMessageHandling.PluginFeature] {
-    [.loadPluginLibrary]
-  }
-}
-
-struct PluginServerError: Error, CustomStringConvertible {
-  var description: String
-  init(message: String) {
-    self.description = message
+    listener.main()
   }
 }