Reland "[clangd] Add feature modules registry"

clang-tools-extra/clangd/FeatureModule.h

@@ -198,4 +198,9 @@ using FeatureModuleRegistry = llvm::Registry<FeatureModule>;
 
 } // namespace clangd
 } // namespace clang
+
+namespace llvm {
+extern template class Registry<clang::clangd::FeatureModule>;
+} // namespace llvm
+
 #endif

clang-tools-extra/clangd/unittests/CMakeLists.txt

@@ -54,6 +54,7 @@ add_unittest(ClangdUnitTests ClangdTests
   DumpASTTests.cpp
   ExpectedTypeTest.cpp
   FeatureModulesTests.cpp
+  FeatureModulesRegistryTests.cpp
   FileDistanceTests.cpp
   FileIndexTests.cpp
   FindSymbolsTests.cpp
@@ -154,6 +155,8 @@ target_include_directories(ClangdTests PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
 )
 
+add_subdirectory(feature-modules)
+
 clang_target_link_libraries(ClangdTests
   PRIVATE
   clangAST
@@ -183,6 +186,8 @@ target_link_libraries(ClangdTests
   clangTidy
   clangTidyUtils
   clangdSupport
+
+  ${FEATURE_MODULES}
   )
 
 if (CLANGD_ENABLE_REMOTE)

clang-tools-extra/clangd/unittests/FeatureModulesRegistryTests.cpp

@@ -0,0 +1,66 @@
+//===--- FeatureModulesRegistryTests.cpp  ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "FeatureModule.h"
+#include "feature-modules/ForceLinker.h" // IWYU pragma: keep
+#include "refactor/Tweak.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+using testing::ElementsAre;
+
+namespace llvm {
+raw_ostream &operator<<(raw_ostream &OS,
+                        const clang::clangd::FeatureModuleRegistry::entry &E) {
+  OS << "(name = " << E.getName() << ", description = '" << E.getDesc() << "')";
+  return OS;
+}
+
+raw_ostream &operator<<(
+    raw_ostream &OS,
+    const iterator_range<Registry<clang::clangd::FeatureModule>::iterator>
+        &Rng) {
+  OS << "{ ";
+  bool First = true;
+  for (clang::clangd::FeatureModuleRegistry::entry E : Rng) {
+    if (First)
+      First = false;
+    else
+      OS << ", ";
+    OS << E;
+  }
+  OS << " }";
+  return OS;
+}
+
+raw_ostream &operator<<(raw_ostream &OS, const clang::clangd::Tweak &T) {
+  OS << "(id = " << T.id() << ", "
+     << "title = " << T.title() << ")";
+  return OS;
+}
+} // namespace llvm
+
+namespace clang::clangd {
+namespace {
+
+MATCHER_P(moduleName, Name, "") { return arg.getName() == Name; }
+MATCHER_P(tweakID, ID, "") { return arg->id() == ID; }
+
+TEST(FeatureModulesRegistryTest, DummyModule) {
+  EXPECT_THAT(FeatureModuleRegistry::entries(),
+              ElementsAre(moduleName("dummy")));
+  FeatureModuleSet Set = FeatureModuleSet::fromRegistry();
+  ASSERT_EQ(Set.end() - Set.begin(), 1u);
+  std::vector<std::unique_ptr<Tweak>> Tweaks;
+  Set.begin()->contributeTweaks(Tweaks);
+  EXPECT_THAT(Tweaks, ElementsAre(tweakID("DummyTweak")));
+}
+
+} // namespace
+} // namespace clang::clangd

clang-tools-extra/clangd/unittests/feature-modules/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_subdirectory(dummy)
+set(FEATURE_MODULES ${FEATURE_MODULES} PARENT_SCOPE)

clang-tools-extra/clangd/unittests/feature-modules/ForceLinker.h

@@ -0,0 +1,20 @@
+//===- ForceLinker.h ----------------------------------------------*-C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_UNITTEST_FEATURE_MODULES_FORCE_LINKER_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_UNITTEST_FEATURE_MODULES_FORCE_LINKER_H
+
+#include "llvm/Support/Compiler.h"
+
+namespace clang::clangd {
+extern volatile int DummyFeatureModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED DummyFeatureModuleAnchorDestination =
+    DummyFeatureModuleAnchorSource;
+} // namespace clang::clangd
+
+#endif

clang-tools-extra/clangd/unittests/feature-modules/dummy/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_llvm_library(dummyFeatureModule DummyFeatureModule.cpp)
+set(FEATURE_MODULES ${FEATURE_MODULES} dummyFeatureModule PARENT_SCOPE)

clang-tools-extra/clangd/unittests/feature-modules/dummy/DummyFeatureModule.cpp

@@ -0,0 +1,41 @@
+//===--- DummyFeatureModule.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "FeatureModule.h"
+#include "refactor/Tweak.h"
+#include "support/Logger.h"
+
+namespace clang::clangd {
+
+class Dummy final : public FeatureModule {
+  static constexpr const char *TweakID = "DummyTweak";
+  struct DummyTweak final : public Tweak {
+    const char *id() const override { return TweakID; }
+    bool prepare(const Selection &) override { return true; }
+    Expected<Effect> apply(const Selection &) override {
+      return error("not implemented");
+    }
+    std::string title() const override { return id(); }
+    llvm::StringLiteral kind() const override {
+      return llvm::StringLiteral("");
+    };
+  };
+
+  void contributeTweaks(std::vector<std::unique_ptr<Tweak>> &Out) override {
+    Out.emplace_back(new DummyTweak);
+  }
+};
+
+static FeatureModuleRegistry::Add<Dummy>
+    X("dummy", "Dummy feature module with dummy tweak");
+
+// This anchor is used to force the linker to link in the generated object file
+// and thus register the Dummy feature module.
+volatile int DummyFeatureModuleAnchorSource = 0;
+
+} // namespace clang::clangd