Demonstrator of a real plugin to clang-tidy

 * Adding a toy plugin clang-tidy module which is compiled
   into a shared lib
 * This plugin can be activated using LD_PRELOAD
 * This enables (in principle) a complete decoupling of our check developments
   to the clang-tidy binary

Author: sawenzel

CMakeLists.txt

@@ -46,6 +46,8 @@ add_subdirectory(aliceO2)
 # the specific reporting tools code
 add_subdirectory(reporting)
 
+# plugin
+add_subdirectory(plugin)
 
 # for testing
 add_subdirectory(test)

plugin/CMakeLists.txt

@@ -0,0 +1,17 @@
+set(LLVM_LINK_COMPONENTS support)
+
+add_clang_library(clangTidyPluginModule
+  SHARED
+
+  FooCheck.cpp
+  PluginTidyModule.cpp
+
+  LINK_LIBS
+  clangAST
+  clangASTMatchers
+  clangBasic
+  clangLex
+  clangTidy
+  clangTidyUtils
+  clangTooling
+  )

plugin/FooCheck.cpp

@@ -0,0 +1,34 @@
+//===--- FooCheck.cpp - clang-tidy-----------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "FooCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace plugin {
+
+void FooCheck::registerMatchers(MatchFinder *Finder) {
+  // FIXME: Add matchers.
+  Finder->addMatcher(functionDecl().bind("x"), this);
+}
+
+void FooCheck::check(const MatchFinder::MatchResult &Result) {
+  // FIXME: Add callback implementation.
+  const auto *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("x");
+  diag(MatchedDecl->getLocation(), "you should not use functions")
+      << MatchedDecl;
+}
+
+} // namespace plugin
+} // namespace tidy
+} // namespace clang

plugin/FooCheck.h

@@ -0,0 +1,35 @@
+//===--- FooCheck.h - clang-tidy---------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PLUGIN_FOO_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PLUGIN_FOO_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace plugin {
+
+/// FIXME: Write a short description.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/plugin-Foo.html
+class FooCheck : public ClangTidyCheck {
+public:
+  FooCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace plugin
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PLUGIN_FOO_H

plugin/PluginTidyModule.cpp

@@ -0,0 +1,48 @@
+//===--- AliceO2TidyModule.cpp - clang-tidy ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "../ClangTidy.h"
+#include "../ClangTidyModule.h"
+#include "../ClangTidyModuleRegistry.h"
+#include "FooCheck.h"
+#include <iostream>
+
+namespace clang {
+namespace tidy {
+namespace plugin {
+
+class PluginModule : public ClangTidyModule {
+public:
+  void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+    std::cerr << "side effect \n";
+    CheckFactories.registerCheck<FooCheck>(
+        "plugin-Foo");
+  }
+};
+
+} // namespace plugin
+
+// Register the AliceO2TidyModule using this statically initialized variable.
+static ClangTidyModuleRegistry::Add<plugin::PluginModule>
+X("aliceO2-module", "Adds AliceO2 specific checks");
+
+// This anchor is used to force the linker to link in the generated object file
+// and thus register the AliceO2Module.
+volatile int PluginModuleAnchorSource = 0;
+
+} // namespace tidy
+} // namespace clang
+
+
+// A function to execute upon load of shared library
+//__attribute__((constructor))
+static int huhuhuhuhu() {
+  static clang::tidy::plugin::PluginModule module;
+  return clang::tidy::PluginModuleAnchorSource;
+}