[clang-tidy] Define __clang_analyzer__ macro for clang-tidy for compatibility with clang static analyzer. 2nd try.

[zinovy.nis]

Summary

This macro is widely used in many well-known projects, ex. Chromium.

But it's not set for clang-tidy, so for ex. DCHECK in Chromium is not considered as [[no-return]], and a lot of false-positive warnings about nullptr dereferenced are emitted.

This patch fixes the issue.
This revision is the second version of https://reviews.llvm.org/D44906.

[alexfh]

clang-tidy/ClangTidy.cpp

536 ↗

(On Diff #144757)

I would add a comment that we only do this to define the analyzer-specific macro, not to actually use the analyzer frontend action.

[zinovy.nis]

• Added comments on why setting ProgramAction explicitly.

[alexfh]

LG. Thank you!

[zinovy.nis]

Thanks Alexander for your feedback!

clang-tools-extra/trunk/clang-tidy/ClangTidy.cpp

void runClangTidy(clang::tidy::ClangTidyContext &Context,
 
   Tool.setDiagnosticConsumer(&DiagConsumer);
 
   class ActionFactory : public FrontendActionFactory {
   public:
     ActionFactory(ClangTidyContext &Context) : ConsumerFactory(Context) {}
     FrontendAction *create() override { return new Action(&ConsumerFactory); }
 
+    bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
+                       FileManager *Files,
+                       std::shared_ptr<PCHContainerOperations> PCHContainerOps,
+                       DiagnosticConsumer *DiagConsumer) override {
+      // Explicitly set ProgramAction to RunAnalysis to make the preprocessor
+      // define __clang_analyzer__ macro. The frontend analyzer action will not
+      // be called here.
+      Invocation->getFrontendOpts().ProgramAction = frontend::RunAnalysis;
+      return FrontendActionFactory::runInvocation(
+          Invocation, Files, PCHContainerOps, DiagConsumer);
+    }
+
   private:
     class Action : public ASTFrontendAction {
     public:
       Action(ClangTidyASTConsumerFactory *Factory) : Factory(Factory) {}
       std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &Compiler,
                                                      StringRef File) override {
         return Factory->CreateASTConsumer(Compiler, File);
       }

clang-tools-extra/trunk/test/clang-tidy/clang-tidy-__clang_analyzer__macro.cpp

+// RUN: clang-tidy %s -checks=-*,modernize-use-nullptr -- | count 0
+
+#if !defined(__clang_analyzer__)
+#error __clang_analyzer__ is not defined
+#endif
+// RUN: clang-tidy %s -checks=-*,modernize-use-nullptr -- | count 0
+
+#if !defined(__clang_analyzer__)
+#error __clang_analyzer__ is not defined
+#endif