[clangd] NFC: Use buildCompilerInvocation in CodeComplete

[ilya-biryukov]

clangd/CodeComplete.cpp

1030

remove this line, buildCompilerInvocation handles this for us

1032

remove this line, buildCompilerInvocation handles this for us

[ilya-biryukov]

Adding Sam as a reviewer, IIRC we used to have buildCompilerInvocation here and he was the one who inlined it.
I would personally LGTM this change (with the two comments fixed), but Sam might have a different opinion on whether this should be outlined again.

[sammccall]

In D56860#1365432, @ilya-biryukov wrote:

Adding Sam as a reviewer, IIRC we used to have buildCompilerInvocation here and he was the one who inlined it.
I would personally LGTM this change (with the two comments fixed), but Sam might have a different opinion on whether this should be outlined again.

I inlined it because buildCompilerInvocation was private, and I was moving CodeComplete out of ClangdUnit.cpp in rL319655.
The function was made public in rL333737 as part of a larger change.
I don't really object to the patch as it is, but if you're open to suggestions...

I'd prefer to have fewer dependencies between CodeComplete and ClangdUnit, as the latter has historically been a hairball.
Can we move buildCompilerInvocation and ParseInputs into Compiler.h, which is simplified APIs for invoking the compiler?
Both ClangdUnit and CodeComplete can certainly use Compiler, no question.

[kadircet]

• Moved ParseInputs and buildCompilerInvocation into Compiler.h

[sammccall]

Thank you!

clangd/CodeComplete.cpp

 
 // Invokes Sema code completion on a file.
 // If \p Includes is set, it will be updated based on the compiler invocation.
 bool semaCodeComplete(std::unique_ptr<CodeCompleteConsumer> Consumer,
                       const clang::CodeCompleteOptions &Options,
                       const SemaCompleteInput &Input,
                       IncludeStructure *Includes = nullptr) {
   trace::Span Tracer("Sema completion");
-  std::vector<const char *> ArgStrs;
-  for (const auto &S : Input.Command.CommandLine)
-    ArgStrs.push_back(S.c_str());
-
-  if (Input.VFS->setCurrentWorkingDirectory(Input.Command.Directory)) {
-    log("Couldn't set working directory");
-    // We run parsing anyway, our lit-tests rely on results for non-existing
-    // working dirs.
-  }
-
   llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS = Input.VFS;
   if (Input.Preamble && Input.Preamble->StatCache)
     VFS = Input.Preamble->StatCache->getConsumingFS(std::move(VFS));
-  IgnoreDiagnostics DummyDiagsConsumer;
-  auto CI = createInvocationFromCommandLine(
-      ArgStrs,
-      CompilerInstance::createDiagnostics(new DiagnosticOptions,
-                                          &DummyDiagsConsumer, false),
-      VFS);
+  auto CI =
+      buildCompilerInvocation(ParseInputs{Input.Command, VFS, Input.Contents});
   if (!CI) {
     elog("Couldn't create CompilerInvocation");
     return false;
   }
   auto &FrontendOpts = CI->getFrontendOpts();
   FrontendOpts.DisableFree = false;
   FrontendOpts.SkipFunctionBodies = true;
   CI->getLangOpts()->CommentOpts.ParseAllComments = true;
   // Disable typo correction in Sema.
   CI->getLangOpts()->SpellChecking = false;
   // Setup code completion.
   FrontendOpts.CodeCompleteOpts = Options;
   FrontendOpts.CodeCompletionAt.FileName = Input.FileName;
   auto Offset = positionToOffset(Input.Contents, Input.Pos);
   if (!Offset) {
     elog("Code completion position was invalid {0}", Offset.takeError());
bool semaCodeComplete(std::unique_ptr<CodeCompleteConsumer> Consumer,
   // However, if we're completing *inside* the preamble section of the draft,
   // overriding the preamble will break sema completion. Fortunately we can just
   // skip all includes in this case; these completions are really simple.
   bool CompletingInPreamble =
       ComputePreambleBounds(*CI->getLangOpts(), ContentsBuffer.get(), 0).Size >
       *Offset;
   // NOTE: we must call BeginSourceFile after prepareCompilerInstance. Otherwise
   // the remapped buffers do not get freed.
+  IgnoreDiagnostics DummyDiagsConsumer;
   auto Clang = prepareCompilerInstance(
       std::move(CI),
       (Input.Preamble && !CompletingInPreamble) ? &Input.Preamble->Preamble
                                                 : nullptr,
       std::move(ContentsBuffer), std::move(Input.PCHs), std::move(VFS),
       DummyDiagsConsumer);
   Clang->getPreprocessorOpts().SingleFileParseMode = CompletingInPreamble;
   Clang->setCodeCompletionConsumer(Consumer.release());