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

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 {{type 'MacroDefinition.TypeDoesNotExist' could not be found in library plugin '}}
+  // expected-error @+1 {{macro implementation 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

@@ -1,10 +1,29 @@
 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
-      SwiftLibraryPluginProvider
+  )
+  target_include_directories(swift-plugin-server PRIVATE
+    Sources/CSwiftPluginServer/include
   )
 endif()

tools/swift-plugin-server/Package.swift

@@ -11,10 +11,25 @@ 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

@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "PluginServer.h"
+#include "swift/ABI/MetadataValues.h"
+#include "swift/Demangling/Demangle.h"
+#include "llvm/Support/DynamicLibrary.h"
+
+#if defined(_WIN32)
+#include <io.h>
+#elif defined(__unix__) || defined(__APPLE__)
+#include <dlfcn.h>
+#include <unistd.h>
+#endif
+
+#include <string>
+#include <errno.h>
+#include <string.h>
+
+using namespace swift;
+
+void *PluginServer_load(const char *plugin, const char **errorMessage) {
+  // Use a static allocation for the error as the client will not release the
+  // string.  POSIX 2008 (IEEE-1003.1-2008) specifies that it is implementation
+  // defined if `dlerror` is re-entrant.  Take advantage of that and make it
+  // thread-unsafe.  This ensures that the string outlives the call permitting
+  // the client to duplicate it.
+  static std::string error;
+  auto library = llvm::sys::DynamicLibrary::getLibrary(plugin, &error);
+  if (library.isValid())
+    return library.getOSSpecificHandle();
+  *errorMessage = error.c_str();
+  return nullptr;
+}
+
+const void *PluginServer_lookupMacroTypeMetadataByExternalName(
+    const char *moduleName, const char *typeName, void *libraryHint,
+    const char **errorMessage) {
+  // Look up the type metadata accessor as a struct, enum, or class.
+  const Demangle::Node::Kind typeKinds[] = {
+      Demangle::Node::Kind::Structure,
+      Demangle::Node::Kind::Enum,
+      Demangle::Node::Kind::Class,
+  };
+
+  void *accessorAddr = nullptr;
+  for (auto typeKind : typeKinds) {
+    auto symbolName =
+        mangledNameForTypeMetadataAccessor(moduleName, typeName, typeKind);
+
+#if !defined(_WIN32)
+    if (libraryHint == nullptr)
+      libraryHint = RTLD_DEFAULT;
+#endif
+    accessorAddr = llvm::sys::DynamicLibrary{libraryHint}
+                      .getAddressOfSymbol(symbolName.c_str());
+    if (accessorAddr)
+      break;
+  }
+
+  if (!accessorAddr)
+    return nullptr;
+
+  // Call the accessor to form type metadata.
+  using MetadataAccessFunc = const void *(MetadataRequest);
+  auto accessor = reinterpret_cast<MetadataAccessFunc*>(accessorAddr);
+  return accessor(MetadataRequest(MetadataState::Complete));
+}

tools/swift-plugin-server/Sources/CSwiftPluginServer/include/PluginServer.h

@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_PLUGINSERVER_PLUGINSERVER_H
+#define SWIFT_PLUGINSERVER_PLUGINSERVER_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//===----------------------------------------------------------------------===//
+// Dynamic link
+//===----------------------------------------------------------------------===//
+
+/// Load a dynamic link library, and return the handle.
+void *PluginServer_load(const char *filename, const char **errorMessage);
+
+/// Resolve a type metadata by a pair of the module name and the type name.
+/// 'libraryHint' is a
+const void *PluginServer_lookupMacroTypeMetadataByExternalName(
+    const char *moduleName, const char *typeName, void *libraryHint,
+    const char **errorMessage);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SWIFT_PLUGINSERVER_PLUGINSERVER_H */

tools/swift-plugin-server/Sources/CSwiftPluginServer/include/module.modulemap

@@ -0,0 +1,4 @@
+module CSwiftPluginServer {
+  header "PluginServer.h"
+  export *
+}

tools/swift-plugin-server/Sources/swift-plugin-server/swift-plugin-server.swift

@@ -11,16 +11,96 @@
 //===----------------------------------------------------------------------===//
 
 @_spi(PluginMessage) import SwiftCompilerPluginMessageHandling
-@_spi(PluginMessage) import SwiftLibraryPluginProvider
+import SwiftSyntaxMacros
+import CSwiftPluginServer
 
 @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: LibraryPluginProvider.shared
+      provider: self.init()
     )
-    listener.main()
+    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
   }
 }