[clangd] Correct setting ignoreWarnings in CodeCompletion.

hokein · hokein · commit b603a5e0e376 · 2018-02-22T13:35:01.000Z
Summary: We should set the flag before creating ComplierInstance -- when CopmilerInstance gets initialized, it also initializes the DiagnosticsEngine using the DiagnosticOptions. This was hidden deeply -- as clang suppresses all diagnostics when we hit the code-completion (but internally it does do unnecessary analysis stuff). As a bonus point, this fix will optmize the completion speed -- clang won't do any analysis (e.g. -Wunreachable-code, -Wthread-safety-analysisi) at all internally. Reviewers: ilya-biryukov Reviewed By: ilya-biryukov Subscribers: klimek, jkorous-apple, ioeric, cfe-commits Differential Revision: https://reviews.llvm.org/D43569 llvm-svn: 325779
diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -696,11 +696,11 @@ bool semaCodeComplete(std::unique_ptr<CodeCompleteConsumer> Consumer,
     Input.Preamble->CanReuse(*CI, ContentsBuffer.get(), Bounds,
                              Input.VFS.get());
   }
+  // The diagnostic options must be set before creating a CompilerInstance.
+  CI->getDiagnosticOpts().IgnoreWarnings = true;
   auto Clang = prepareCompilerInstance(
       std::move(CI), Input.Preamble, std::move(ContentsBuffer),
       std::move(Input.PCHs), std::move(Input.VFS), DummyDiagsConsumer);
-  auto &DiagOpts = Clang->getDiagnosticOpts();
-  DiagOpts.IgnoreWarnings = true;
 
   // Disable typo correction in Sema.
   Clang->getLangOpts().SpellChecking = false;
diff --git a/clang-tools-extra/clangd/Headers.cpp b/clang-tools-extra/clangd/Headers.cpp
@@ -79,12 +79,12 @@ calculateIncludePath(llvm::StringRef File, llvm::StringRef Code,
   // added more than once.
   CI->getPreprocessorOpts().SingleFileParseMode = true;
 
+  // The diagnostic options must be set before creating a CompilerInstance.
+  CI->getDiagnosticOpts().IgnoreWarnings = true;
   auto Clang = prepareCompilerInstance(
       std::move(CI), /*Preamble=*/nullptr,
       llvm::MemoryBuffer::getMemBuffer(Code, File),
       std::make_shared<PCHContainerOperations>(), FS, IgnoreDiags);
-  auto &DiagOpts = Clang->getDiagnosticOpts();
-  DiagOpts.IgnoreWarnings = true;
 
   if (Clang->getFrontendOpts().Inputs.empty())
     return llvm::make_error<llvm::StringError>(
