[clangd] Respect clang-tidy suppression comments

This partially fixes https://bugs.llvm.org/show_bug.cgi?id=41218.

Reviewed By: sammccall

Patch by Nathan Ridge!

Differential Revision: https://reviews.llvm.org/D60953

llvm-svn: 361112

clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp

@@ -166,11 +166,13 @@ class ClangTidyContext::CachedGlobList {
 
   bool contains(StringRef S) {
     switch (auto &Result = Cache[S]) {
-      case Yes: return true;
-      case No: return false;
-      case None:
-        Result = Globs.contains(S) ? Yes : No;
-        return Result == Yes;
+    case Yes:
+      return true;
+    case No:
+      return false;
+    case None:
+      Result = Globs.contains(S) ? Yes : No;
+      return Result == Yes;
     }
     llvm_unreachable("invalid enum");
   }
@@ -387,16 +389,30 @@ static bool LineIsMarkedWithNOLINTinMacro(const SourceManager &SM,
   return false;
 }
 
+namespace clang {
+namespace tidy {
+
+bool ShouldSuppressDiagnostic(DiagnosticsEngine::Level DiagLevel,
+                              const Diagnostic &Info, ClangTidyContext &Context,
+                              bool CheckMacroExpansion) {
+  return Info.getLocation().isValid() &&
+         DiagLevel != DiagnosticsEngine::Error &&
+         DiagLevel != DiagnosticsEngine::Fatal &&
+         (CheckMacroExpansion ? LineIsMarkedWithNOLINTinMacro
+                              : LineIsMarkedWithNOLINT)(Info.getSourceManager(),
+                                                        Info.getLocation(),
+                                                        Info.getID(), Context);
+}
+
+} // namespace tidy
+} // namespace clang
+
 void ClangTidyDiagnosticConsumer::HandleDiagnostic(
     DiagnosticsEngine::Level DiagLevel, const Diagnostic &Info) {
   if (LastErrorWasIgnored && DiagLevel == DiagnosticsEngine::Note)
     return;
 
-  if (Info.getLocation().isValid() && DiagLevel != DiagnosticsEngine::Error &&
-      DiagLevel != DiagnosticsEngine::Fatal &&
-      LineIsMarkedWithNOLINTinMacro(Info.getSourceManager(),
-                                    Info.getLocation(), Info.getID(),
-                                    Context)) {
+  if (ShouldSuppressDiagnostic(DiagLevel, Info, Context)) {
     ++Context.Stats.ErrorsIgnoredNOLINT;
     // Ignored a warning, should ignore related notes as well
     LastErrorWasIgnored = true;

clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.h

@@ -217,6 +217,23 @@ class ClangTidyContext {
   bool AllowEnablingAnalyzerAlphaCheckers;
 };
 
+/// Check whether a given diagnostic should be suppressed due to the presence
+/// of a "NOLINT" suppression comment.
+/// This is exposed so that other tools that present clang-tidy diagnostics
+/// (such as clangd) can respect the same suppression rules as clang-tidy.
+/// This does not handle suppression of notes following a suppressed diagnostic;
+/// that is left to the caller is it requires maintaining state in between calls
+/// to this function.
+/// The `CheckMacroExpansion` parameter determines whether the function should
+/// handle the case where the diagnostic is inside a macro expansion. A degree
+/// of control over this is needed because handling this case can require
+/// examining source files other than the one in which the diagnostic is
+/// located, and in some use cases we cannot rely on such other files being
+/// mapped in the SourceMapper.
+bool ShouldSuppressDiagnostic(DiagnosticsEngine::Level DiagLevel,
+                              const Diagnostic &Info, ClangTidyContext &Context,
+                              bool CheckMacroExpansion = true);
+
 /// \brief A diagnostic consumer that turns each \c Diagnostic into a
 /// \c SourceManager-independent \c ClangTidyError.
 //
@@ -246,7 +263,7 @@ class ClangTidyDiagnosticConsumer : public DiagnosticConsumer {
 
   /// \brief Updates \c LastErrorRelatesToUserCode and LastErrorPassesLineFilter
   /// according to the diagnostic \p Location.
-  void checkFilters(SourceLocation Location, const SourceManager& Sources);
+  void checkFilters(SourceLocation Location, const SourceManager &Sources);
   bool passesLineFilter(StringRef FileName, unsigned LineNumber) const;
 
   ClangTidyContext &Context;

clang-tools-extra/clangd/ClangdUnit.cpp

@@ -113,12 +113,12 @@ class CollectMainFileMacros : public PPCallbacks {
   }
 
   void EndOfMainFile() {
-    for (const auto& Entry : MainFileMacros)
+    for (const auto &Entry : MainFileMacros)
       Out->push_back(Entry.getKey());
     llvm::sort(*Out);
   }
 
- private:
+private:
   const SourceManager &SM;
   bool InMainFile = true;
   llvm::StringSet<> MainFileMacros;
@@ -332,6 +332,30 @@ ParsedAST::build(std::unique_ptr<CompilerInvocation> CI,
     CTContext->setASTContext(&Clang->getASTContext());
     CTContext->setCurrentFile(MainInput.getFile());
     CTFactories.createChecks(CTContext.getPointer(), CTChecks);
+    ASTDiags.suppressDiagnostics([&CTContext](
+                                     DiagnosticsEngine::Level DiagLevel,
+                                     const clang::Diagnostic &Info) {
+      if (CTContext) {
+        bool IsClangTidyDiag = !CTContext->getCheckName(Info.getID()).empty();
+        if (IsClangTidyDiag) {
+          // Skip the ShouldSuppressDiagnostic check for diagnostics not in
+          // the main file, because we don't want that function to query the
+          // source buffer for preamble files. For the same reason, we ask
+          // ShouldSuppressDiagnostic not to follow macro expansions, since
+          // those might take us into a preamble file as well.
+          bool IsInsideMainFile =
+              Info.hasSourceManager() &&
+              Info.getSourceManager().isWrittenInMainFile(
+                  Info.getSourceManager().getFileLoc(Info.getLocation()));
+          if (IsInsideMainFile && tidy::ShouldSuppressDiagnostic(
+                                      DiagLevel, Info, *CTContext,
+                                      /* CheckMacroExpansion = */ false)) {
+            return true;
+          }
+        }
+      }
+      return false;
+    });
     Preprocessor *PP = &Clang->getPreprocessor();
     for (const auto &Check : CTChecks) {
       // FIXME: the PP callbacks skip the entire preamble.

clang-tools-extra/clangd/Diagnostics.cpp

@@ -514,6 +514,12 @@ void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
     // Handle the new main diagnostic.
     flushLastDiag();
 
+    if (SuppressionFilter && SuppressionFilter(DiagLevel, Info)) {
+      LastPrimaryDiagnosticWasSuppressed = true;
+      return;
+    }
+    LastPrimaryDiagnosticWasSuppressed = false;
+
     LastDiag = Diag();
     LastDiag->ID = Info.getID();
     FillDiagBase(*LastDiag);
@@ -528,6 +534,13 @@ void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
     }
   } else {
     // Handle a note to an existing diagnostic.
+
+    // If a diagnostic was suppressed due to the suppression filter,
+    // also suppress notes associated with it.
+    if (LastPrimaryDiagnosticWasSuppressed) {
+      return;
+    }
+
     if (!LastDiag) {
       assert(false && "Adding a note without main diagnostic");
       IgnoreDiagnostics::log(DiagLevel, Info);

clang-tools-extra/clangd/Diagnostics.h

@@ -128,17 +128,25 @@ class StoreDiags : public DiagnosticConsumer {
 
   using DiagFixer = std::function<std::vector<Fix>(DiagnosticsEngine::Level,
                                                    const clang::Diagnostic &)>;
+  using DiagFilter =
+      std::function<bool(DiagnosticsEngine::Level, const clang::Diagnostic &)>;
   /// If set, possibly adds fixes for diagnostics using \p Fixer.
   void contributeFixes(DiagFixer Fixer) { this->Fixer = Fixer; }
+  /// If set, ignore diagnostics for which \p SuppressionFilter returns true.
+  void suppressDiagnostics(DiagFilter SuppressionFilter) {
+    this->SuppressionFilter = SuppressionFilter;
+  }
 
 private:
   void flushLastDiag();
 
   DiagFixer Fixer = nullptr;
+  DiagFilter SuppressionFilter = nullptr;
   std::vector<Diag> Output;
   llvm::Optional<LangOptions> LangOpts;
   llvm::Optional<Diag> LastDiag;
   llvm::DenseSet<int> IncludeLinesWithErrors;
+  bool LastPrimaryDiagnosticWasSuppressed = false;
 };
 
 } // namespace clangd

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

@@ -207,6 +207,26 @@ TEST(DiagnosticsTest, ClangTidy) {
                "multiple unsequenced modifications to 'y'")));
 }
 
+TEST(DiagnosticTest, ClangTidySuppressionComment) {
+  Annotations Main(R"cpp(
+    int main() {
+      int i = 3;
+      double d = 8 / i;  // NOLINT
+      // NOLINTNEXTLINE
+      double e = 8 / i;
+      double f = [[8]] / i;
+    }
+  )cpp");
+  TestTU TU = TestTU::withCode(Main.code());
+  TU.ClangTidyChecks = "bugprone-integer-division";
+  EXPECT_THAT(
+      TU.build().getDiagnostics(),
+      UnorderedElementsAre(::testing::AllOf(
+          Diag(Main.range(), "result of integer division used in a floating "
+                             "point context; possible loss of precision"),
+          DiagSource(Diag::ClangTidy), DiagName("bugprone-integer-division"))));
+}
+
 TEST(DiagnosticsTest, Preprocessor) {
   // This looks like a preamble, but there's an #else in the middle!
   // Check that:
@@ -767,6 +787,7 @@ TEST(DiagsInHeaders, OnlyErrorOrFatal) {
                                      "a type specifier for all declarations"),
                   WithNote(Diag(Header.range(), "error occurred here")))));
 }
+
 } // namespace
 
 } // namespace clangd