[clang-tidy] Add library for clang-tidy main function

[DmitryPolukhin]

Summary

This library allows to create clang-tidy tools with custom checks outside of llvm repo
using prebuilt clang release tarball.

Test Plan:
Checked that clang-tidy works as before. New library exists in istall dir.

[Eugene.Zelenko]

clang-tools-extra/clang-tidy/tool/ClangTidyMain.h

6

License seems to be old.

clang-tools-extra/clang-tidy/tool/ClangTidyToolMain.cpp

6

License seems to be old.

[DmitryPolukhin]

Fix license text

[DmitryPolukhin]

@Eugene.Zelenko thank you for the catch

[gribozavr2]

clang-tools-extra/clang-tidy/tool/ClangTidyMain.h

9

"... declares the main function for the clang-tidy tool."

[DmitryPolukhin]

Updated comment per review suggestion.

[DmitryPolukhin]

Added #include "ClangTidyMain.h" in ClangTidyMain.cpp

[thakis]

clang-tools-extra/clang-tidy/tool/CMakeLists.txt

22

Normally we have a single cmake target per CMakeLists.txt. Maybe the library could be in clang-tidy/lib and clang-tidy/tool could use it? Then you wouldn't need the LLVM_OPTIONAL_SOURCES hack and it'd be all a bit nicer.

[DmitryPolukhin]

clang-tools-extra/clang-tidy/tool/CMakeLists.txt

22

I'll prepare patch with files move if you think it worths doing. I see multiple targets in several CMakeLists.txt:

llvm-project> grep LLVM_OPTIONAL_SOURCES ./ -r
./clang-tools-extra/clang-tidy/tool/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES ClangTidyMain.cpp ClangTidyToolMain.cpp)
./clang-tools-extra/clangd/xpc/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES Conversion.cpp XPCTransport.cpp)
./clang/tools/clang-fuzzer/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES
./clang/tools/clang-fuzzer/CMakeLists.txt:  set(LLVM_OPTIONAL_SOURCES ${LLVM_OPTIONAL_SOURCES} ${PROTO_SRCS})
./clang/tools/clang-fuzzer/proto-to-cxx/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES proto_to_cxx.cpp proto_to_cxx_main.cpp
./clang/tools/clang-fuzzer/proto-to-llvm/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES loop_proto_to_llvm.cpp loop_proto_to_llvm_main.cpp)
./lldb/source/Plugins/Platform/MacOSX/CMakeLists.txt:  list(APPEND LLVM_OPTIONAL_SOURCES
./lldb/source/Symbol/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES LocateSymbolFileMacOSX.cpp)
./lldb/tools/debugserver/source/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES ${lldbDebugserverCommonSources})
./llvm/cmake/modules/AddLLVM.cmake:    set(LLVM_OPTIONAL_SOURCES ${ARG_DUMMY_MAIN})
./llvm/cmake/modules/AddLLVM.cmake:    set(LLVM_OPTIONAL_SOURCES ${ARG_DUMMY_MAIN})
./llvm/cmake/modules/LLVMProcessSources.cmake:      list(FIND LLVM_OPTIONAL_SOURCES ${entry} idx)
./llvm/unittests/Passes/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES PluginsTest.cpp TestPlugin.cpp)
./llvm/unittests/Support/DynamicLibrary/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES ExportedFuncs.cpp PipSqueak.cpp)
./mlir/lib/EDSC/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES
./mlir/lib/Support/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES
./mlir/test/lib/TestDialect/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES
./mlir/test/mlir-cpu-runner/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES
./mlir/tools/mlir-cuda-runner/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES
./mlir/tools/mlir-opt/CMakeLists.txt:set(LLVM_OPTIONAL_SOURCES

[DmitryPolukhin]

@thakis I'm sorry sorry if it was not clear. Please let me know if you still prefer to have separate directory for clangTidyMain to have only one target per CMakeLists.txt.

clang-tools-extra/clang-tidy/tool/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   AllTargetsAsmParsers
   AllTargetsDescs
   AllTargetsInfos
   support
   )
 
-add_clang_tool(clang-tidy
+# Needed by LLVM's CMake checks because this file defines multiple targets.
+set(LLVM_OPTIONAL_SOURCES ClangTidyMain.cpp ClangTidyToolMain.cpp)
+
+add_clang_library(clangTidyMain
   ClangTidyMain.cpp
+
+  LINK_LIBS
+  clangAST
+  clangASTMatchers
+  clangBasic
+  clangTidy
+  ${ALL_CLANG_TIDY_CHECKS}
+  clangTooling
+  clangToolingCore
+  )
+
+add_clang_tool(clang-tidy
+  ClangTidyToolMain.cpp
   )
 add_dependencies(clang-tidy
   clang-resource-headers
   )
 clang_target_link_libraries(clang-tidy
   PRIVATE
   clangAST
   clangASTMatchers
   clangBasic
   clangTooling
   clangToolingCore
   )
 target_link_libraries(clang-tidy
   PRIVATE
   clangTidy
+  clangTidyMain
   ${ALL_CLANG_TIDY_CHECKS}
   )
 
 
 install(PROGRAMS clang-tidy-diff.py
   DESTINATION share/clang
   COMPONENT clang-tidy)
 install(PROGRAMS run-clang-tidy.py
   DESTINATION share/clang
   COMPONENT clang-tidy)

clang-tools-extra/clang-tidy/tool/ClangTidyMain.h

+//===--- tools/extra/clang-tidy/ClangTidyMain.h - Clang tidy tool -------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+///  \file This file declares clang-tidy tool main function.
+///
+///  This tool uses the Clang Tooling infrastructure, see
+///    http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
+///  for details on setting it up with LLVM source tree.
+///
+//===----------------------------------------------------------------------===//
+
+namespace clang {
+namespace tidy {
+
+int clangTidyMain(int argc, const char **argv);
+
+} // namespace tidy
+} // namespace clang

clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp

getVfsFromFile(const std::string &OverlayFile,
   if (!FS) {
     llvm::errs() << "Error: invalid virtual filesystem overlay file '"
                  << OverlayFile << "'.\n";
     return nullptr;
   }
   return FS;
 }
 
-static int clangTidyMain(int argc, const char **argv) {
+int clangTidyMain(int argc, const char **argv) {
   llvm::InitLLVM X(argc, argv);
   CommonOptionsParser OptionsParser(argc, argv, ClangTidyCategory,
                                     cl::ZeroOrMore);
   llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> BaseFS(
       new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
 
   if (!VfsOverlay.empty()) {
     IntrusiveRefCntPtr<vfs::FileSystem> VfsFromFile =
if (FoundErrors) {
     return 1;
   }
 
   return 0;
 }
 
 } // namespace tidy
 } // namespace clang
-
-int main(int argc, const char **argv) {
-  return clang::tidy::clangTidyMain(argc, argv);
-}

clang-tools-extra/clang-tidy/tool/ClangTidyToolMain.cpp

+//===--- tools/extra/clang-tidy/ClangTidyToolMain.cpp - Clang tidy tool ---===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+///  \file This file contains clang-tidy tool entry point main function.
+///
+///  This tool uses the Clang Tooling infrastructure, see
+///    http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
+///  for details on setting it up with LLVM source tree.
+///
+//===----------------------------------------------------------------------===//
+
+#include "ClangTidyMain.h"
+
+int main(int argc, const char **argv) {
+  return clang::tidy::clangTidyMain(argc, argv);
+}