Add a SourceKit plugin to handle code completion requests

Documentation/Environment Variables.md

@@ -18,3 +18,4 @@ The following environment variables can be used to control some behavior in Sour
 - `SOURCEKIT_LSP_KEEP_TEST_SCRATCH_DIR`: Does not delete the temporary files created during test execution. Allows inspection of the test projects after the test finishes.
 - `SOURCEKIT_LSP_TEST_MODULE_CACHE`: Specifies where tests should store their shared module cache. Defaults to writing the module cache to a temporary directory. Intended so that CI systems can clean the module cache directory after running.
 - `SOURCEKIT_LSP_TEST_TIMEOUT`: Override the timeout duration for tests, in seconds.
+- `SOURCEKIT_LSP_TEST_PLUGIN_PATHS`: Load the SourceKit plugins from this path instead of relative to the package's build folder.

Package.swift

@@ -13,6 +13,8 @@ var products: [Product] = [
   .executable(name: "sourcekit-lsp", targets: ["sourcekit-lsp"]),
   .library(name: "_SourceKitLSP", targets: ["SourceKitLSP"]),
   .library(name: "LSPBindings", targets: ["LanguageServerProtocol", "LanguageServerProtocolJSONRPC"]),
+  .library(name: "SwiftSourceKitPlugin", type: .dynamic, targets: ["SwiftSourceKitPlugin"]),
+  .library(name: "SwiftSourceKitClientPlugin", type: .dynamic, targets: ["SwiftSourceKitClientPlugin"]),
 ]
 
 var targets: [Target] = [
@@ -109,6 +111,45 @@ var targets: [Target] = [
     dependencies: []
   ),
 
+  .target(
+    name: "CCompletionScoring",
+    dependencies: []
+  ),
+
+  // MARK: CompletionScoring
+
+  .target(
+    name: "CompletionScoring",
+    dependencies: ["CCompletionScoring"],
+    swiftSettings: globalSwiftSettings
+  ),
+
+  .target(
+    name: "CompletionScoringForPlugin",
+    dependencies: ["CCompletionScoring"],
+    swiftSettings: globalSwiftSettings
+  ),
+
+  .testTarget(
+    name: "CompletionScoringTests",
+    dependencies: ["CompletionScoring", "CompletionScoringTestSupport", "SwiftExtensions"],
+    swiftSettings: globalSwiftSettings
+  ),
+
+  .testTarget(
+    name: "CompletionScoringPerfTests",
+    dependencies: ["CompletionScoring", "CompletionScoringTestSupport", "SwiftExtensions"],
+    swiftSettings: globalSwiftSettings
+  ),
+
+  // MARK: CompletionScoringTestSupport
+
+  .target(
+    name: "CompletionScoringTestSupport",
+    dependencies: ["CompletionScoring", "SwiftExtensions"],
+    swiftSettings: globalSwiftSettings
+  ),
+
   // MARK: CSKTestSupport
 
   .target(
@@ -273,6 +314,21 @@ var targets: [Target] = [
     swiftSettings: globalSwiftSettings + lspLoggingSwiftSettings
   ),
 
+  .target(
+    name: "SKLoggingForPlugin",
+    dependencies: [
+      "SwiftExtensionsForPlugin"
+    ],
+    exclude: ["CMakeLists.txt"],
+    swiftSettings: globalSwiftSettings + lspLoggingSwiftSettings + [
+      // We can't depend on swift-crypto in the plugin because we can't module-alias it due to https://github.com/swiftlang/swift-package-manager/issues/8119
+      .define("NO_CRYPTO_DEPENDENCY"),
+      .unsafeFlags([
+        "-module-alias", "SwiftExtensions=SwiftExtensionsForPlugin",
+      ]),
+    ]
+  ),
+
   .testTarget(
     name: "SKLoggingTests",
     dependencies: [
@@ -308,6 +364,21 @@ var targets: [Target] = [
     swiftSettings: globalSwiftSettings
   ),
 
+  .target(
+    name: "SKUtilitiesForPlugin",
+    dependencies: [
+      "SKLoggingForPlugin",
+      "SwiftExtensionsForPlugin",
+    ],
+    exclude: ["CMakeLists.txt"],
+    swiftSettings: globalSwiftSettings + [
+      .unsafeFlags([
+        "-module-alias", "SKLogging=SKLoggingForPlugin",
+        "-module-alias", "SwiftExtensions=SwiftExtensionsForPlugin",
+      ])
+    ]
+  ),
+
   .testTarget(
     name: "SKUtilitiesTests",
     dependencies: [
@@ -354,6 +425,22 @@ var targets: [Target] = [
     swiftSettings: globalSwiftSettings
   ),
 
+  .target(
+    name: "SourceKitDForPlugin",
+    dependencies: [
+      "Csourcekitd",
+      "SKLoggingForPlugin",
+      "SwiftExtensionsForPlugin",
+    ],
+    exclude: ["CMakeLists.txt", "sourcekitd_uids.swift.gyb"],
+    swiftSettings: globalSwiftSettings + [
+      .unsafeFlags([
+        "-module-alias", "SKLogging=SKLoggingForPlugin",
+        "-module-alias", "SwiftExtensions=SwiftExtensionsForPlugin",
+      ])
+    ]
+  ),
+
   .testTarget(
     name: "SourceKitDTests",
     dependencies: [
@@ -429,6 +516,13 @@ var targets: [Target] = [
     swiftSettings: globalSwiftSettings
   ),
 
+  .target(
+    name: "SwiftExtensionsForPlugin",
+    dependencies: ["CAtomics"],
+    exclude: ["CMakeLists.txt"],
+    swiftSettings: globalSwiftSettings
+  ),
+
   .testTarget(
     name: "SwiftExtensionsTests",
     dependencies: [
@@ -439,6 +533,84 @@ var targets: [Target] = [
     swiftSettings: globalSwiftSettings
   ),
 
+  // MARK: SwiftSourceKitClientPlugin
+
+  .target(
+    name: "SwiftSourceKitClientPlugin",
+    dependencies: [
+      "Csourcekitd",
+      "SourceKitDForPlugin",
+      "SwiftExtensionsForPlugin",
+      "SwiftSourceKitPluginCommon",
+    ],
+    swiftSettings: globalSwiftSettings + [
+      .unsafeFlags([
+        "-module-alias", "SourceKitD=SourceKitDForPlugin",
+        "-module-alias", "SwiftExtensions=SwiftExtensionsForPlugin",
+      ])
+    ],
+    linkerSettings: sourcekitLSPLinkSettings
+  ),
+
+  // MARK: SwiftSourceKitPluginCommon
+
+  .target(
+    name: "SwiftSourceKitPluginCommon",
+    dependencies: [
+      "Csourcekitd",
+      "SourceKitDForPlugin",
+      "SwiftExtensionsForPlugin",
+      "SKLoggingForPlugin",
+    ],
+    swiftSettings: globalSwiftSettings + [
+      .unsafeFlags([
+        "-module-alias", "SourceKitD=SourceKitDForPlugin",
+        "-module-alias", "SwiftExtensions=SwiftExtensionsForPlugin",
+        "-module-alias", "SKLogging=SKLoggingForPlugin",
+      ])
+    ]
+  ),
+
+  // MARK: SwiftSourceKitPlugin
+
+  .target(
+    name: "SwiftSourceKitPlugin",
+    dependencies: [
+      "Csourcekitd",
+      "CompletionScoringForPlugin",
+      "SKUtilitiesForPlugin",
+      "SKLoggingForPlugin",
+      "SourceKitDForPlugin",
+      "SwiftSourceKitPluginCommon",
+      "SwiftExtensionsForPlugin",
+    ],
+    swiftSettings: globalSwiftSettings + [
+      .unsafeFlags([
+        "-module-alias", "CompletionScoring=CompletionScoringForPlugin",
+        "-module-alias", "SKUtilities=SKUtilitiesForPlugin",
+        "-module-alias", "SourceKitD=SourceKitDForPlugin",
+        "-module-alias", "SKLogging=SKLoggingForPlugin",
+        "-module-alias", "SwiftExtensions=SwiftExtensionsForPlugin",
+      ])
+    ],
+    linkerSettings: sourcekitLSPLinkSettings
+  ),
+
+  .testTarget(
+    name: "SwiftSourceKitPluginTests",
+    dependencies: [
+      "BuildSystemIntegration",
+      "CompletionScoring",
+      "Csourcekitd",
+      "LanguageServerProtocol",
+      "SKTestSupport",
+      "SourceKitD",
+      "SwiftExtensions",
+      "ToolchainRegistry",
+    ],
+    swiftSettings: globalSwiftSettings
+  ),
+
   // MARK: ToolchainRegistry
 
   .target(
@@ -494,11 +666,11 @@ var targets: [Target] = [
 if buildOnlyTests {
   products = []
   targets = targets.compactMap { target in
-    guard target.isTest || target.name == "SKTestSupport" else {
+    guard target.isTest || target.name.contains("TestSupport") else {
       return nil
     }
     target.dependencies = target.dependencies.filter { dependency in
-      if case .byNameItem(name: "SKTestSupport", _) = dependency {
+      if case .byNameItem(name: let name, _) = dependency, name.contains("TestSupport") {
         return true
       }
       return false

Sources/CCompletionScoring/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_library(CCompletionScoring INTERFACE)
+target_include_directories(CCompletionScoring INTERFACE "include")

Sources/CCompletionScoring/include/CCompletionScoring.h

@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SOURCEKITLSP_CCOMPLETIONSCORING_H
+#define SOURCEKITLSP_CCOMPLETIONSCORING_H
+
+#define _GNU_SOURCE
+#include <string.h>
+
+static inline void *sourcekitlsp_memmem(const void *haystack, size_t haystack_len, const void *needle, size_t needle_len) {
+  #if defined(_WIN32) && !defined(__CYGWIN__)
+  // memmem is not available on Windows
+  if (!haystack || haystack_len == 0) {
+    return NULL;
+  }
+  if (!needle || needle_len == 0) {
+    return NULL;
+  }
+  if (needle_len > haystack_len) {
+    return NULL;
+  }
+
+  for (size_t offset = 0; offset <= haystack_len - needle_len; ++offset) {
+    if (memcmp(haystack + offset, needle, needle_len) == 0) {
+      return (void *)haystack + offset;
+    }
+  }
+  return NULL;
+  #else
+  return memmem(haystack, haystack_len, needle, needle_len);
+  #endif
+}
+
+#endif // SOURCEKITLSP_CCOMPLETIONSCORING_H

Sources/CCompletionScoring/include/module.modulemap

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

Sources/CMakeLists.txt

@@ -4,6 +4,8 @@ add_compile_options("$<$<COMPILE_LANGUAGE:Swift>:SHELL:-swift-version 6>")
 add_subdirectory(BuildServerProtocol)
 add_subdirectory(BuildSystemIntegration)
 add_subdirectory(CAtomics)
+add_subdirectory(CCompletionScoring)
+add_subdirectory(CompletionScoring)
 add_subdirectory(Csourcekitd)
 add_subdirectory(Diagnose)
 add_subdirectory(InProcessClient)
@@ -18,5 +20,8 @@ add_subdirectory(SourceKitLSP)
 add_subdirectory(SourceKitD)
 add_subdirectory(sourcekit-lsp)
 add_subdirectory(SwiftExtensions)
+add_subdirectory(SwiftSourceKitClientPlugin)
+add_subdirectory(SwiftSourceKitPlugin)
+add_subdirectory(SwiftSourceKitPluginCommon)
 add_subdirectory(ToolchainRegistry)
 add_subdirectory(TSCExtensions)

Sources/CompletionScoring/CMakeLists.txt

@@ -0,0 +1,51 @@
+set(sources 
+  Semantics/SemanticClassification.swift
+  Semantics/CompletionScore.swift
+  Semantics/Components
+  Semantics/Components/TypeCompatibility.swift
+  Semantics/Components/StructuralProximity.swift
+  Semantics/Components/Flair.swift
+  Semantics/Components/CompletionKind.swift
+  Semantics/Components/Popularity.swift
+  Semantics/Components/ScopeProximity.swift
+  Semantics/Components/Availability.swift
+  Semantics/Components/SynchronicityCompatibility.swift
+  Semantics/Components/PopularityIndex.swift
+  Semantics/Components/ModuleProximity.swift
+  Semantics/Components/PopularityTable.swift
+  Utilities/UnsafeStackAllocator.swift
+  Utilities/Serialization
+  Utilities/Serialization/BinaryCodable.swift
+  Utilities/Serialization/BinaryEncoder.swift
+  Utilities/Serialization/BinaryDecoder.swift
+  Utilities/Serialization/Conformances
+  Utilities/Serialization/Conformances/Dictionary+BinaryCodable.swift
+  Utilities/Serialization/Conformances/OptionSet+BinaryCodable.swift
+  Utilities/Serialization/Conformances/Optional+BinaryCodable.swift
+  Utilities/Serialization/Conformances/Scalars+BinaryCodable.swift
+  Utilities/Serialization/Conformances/String+BinaryCodable.swift
+  Utilities/Serialization/Conformances/Array+BinaryCodable.swift
+  Utilities/SwiftExtensions.swift
+  Utilities/SelectTopK.swift
+  Utilities/UnsafeArray.swift
+  Text/CandidateBatch.swift
+  Text/MatchCollator.Match.swift
+  Text/UTF8Byte.swift
+  Text/MatchCollator.swift
+  Text/InfluencingIdentifiers.swift
+  Text/MatchCollator.Selection.swift
+  Text/ScoredMatchSelector.swift
+  Text/RejectionFilter.swift
+  Text/Pattern.swift)
+
+add_library(CompletionScoring STATIC ${sources})
+set_target_properties(CompletionScoring PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY})
+target_link_libraries(CompletionScoring PUBLIC
+  CCompletionScoring)
+
+add_library(CompletionScoringForPlugin STATIC ${sources})
+set_target_properties(CompletionScoringForPlugin PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY})
+target_link_libraries(CompletionScoringForPlugin PUBLIC
+  CCompletionScoring)