how to create a virtual file in clang for codecompletion
Im trying to create virtual files for codecompletion in clang. Unfortunately, my application segfaults. I have the following setup:
auto createVirtualFile = [](
clang::CompilerInstance& ci,
std::string name,
llvm::StringRef input
) {
std::unique_ptr<llvm::MemoryBuffer>
MB(llvm::MemoryBuffer::getMemBuffer(input, name));
return std::move(MB);
};
Once the file is created i setup a CodeCompletConsumer:
auto setupCodeComplete = [](
clang::CompilerInstance& ci,
std::string File,
int Line,
int Column
) {
auto& F = ci.getFrontendOpts();
F.CodeCompletionAt.FileName = File;
F.CodeCompletionAt.Line = Line;
F.CodeCompletionAt.Column = Column;
clang::FrontendInputFile FrontFile(File, clang::IK_CXX);
//F.Inputs.push_back(FrontFile);
ci.createCodeCompletionConsumer();
return FrontFile;
};
I invoke those two functions the following way and execute a syntax only action:
auto runCodeCompleteAt = [] (
clang::CompilerInstance& ci,
std::string Filename,
std::string Code,
int Line,
int Column
) {
auto fid = createVirtualFile(ci, Filename, Code);
auto File = setupCodeComplete(ci, Filename, Line, Column);
clang::SyntaxOnlyAction Act;
if (Act.BeginSourceFile(ci, File )) {
Act.Execute(); // segfault
Act.EndSourceFile();
}
};
auto runExample = [](auto& ci){
runCodeCompleterAt(ci, "test.cpp", "std::cou", 1, 7);
}
I appreciate any hints.
The problem is although you can add llvm::MemoryBuffer into clang::FrontendInputFile , clang::SyntaxOnlyAction doesn't accept such input, it will cause assertion failure. As I said in previous answer, you may want to look into ASTUnit::CodeComplete in lib/Frontend/ASTUnit.cpp .
Actually you can use remappedFiles to link a filename with a buffer:
int main()
{
unsigned Line = 2;
unsigned Column = 13;
clang::CompilerInstance ci;
llvm::StringRef codeStr("void MyFoo() {}nint main() {My return 0}");
// Just a dummy filename, the file even doesnt' exist.
std::string Filename("virtualFile.cpp");
std::unique_ptr<llvm::MemoryBuffer> MB(llvm::MemoryBuffer::getMemBuffer(codeStr, Filename));
// Create diagnostics and target
ci.createDiagnostics();
std::shared_ptr<clang::TargetOptions> to = std::make_shared<clang::TargetOptions>();
// clang -v
//to->Triple = "x86_64-pc-win32";
//to->Triple = "x86_64-apple-darwin";
to->Triple = "x86_64-apple-darwin15";
ci.setTarget(clang::TargetInfo::CreateTargetInfo(ci.getDiagnostics(), to));
// Create language options
clang::LangOptions &lo = ci.getLangOpts();
lo.CPlusPlus = true;
lo.CPlusPlus11 = true;
// Create code complete options
clang::CodeCompleteOptions cco;
cco.IncludeMacros = 0;
cco.IncludeCodePatterns = 1;
cco.IncludeGlobals = 1;
cco.IncludeBriefComments = 1;
// Set up the callback, I will go back to this callback class later
auto pCustomCodeCompleteConsumer = new CustomCodeCompleteConsumer(cco);
ci.setCodeCompletionConsumer(pCustomCodeCompleteConsumer);
// Set up code complete postions & file
// Until now I didn't find a way to pass in a string rather than a file name
clang::FrontendOptions& frontendOpts = ci.getFrontendOpts();
frontendOpts.CodeCompletionAt.FileName = Filename;
frontendOpts.CodeCompletionAt.Line = Line;
frontendOpts.CodeCompletionAt.Column = Column;
frontendOpts.Inputs.push_back(clang::FrontendInputFile(Filename, clang::InputKind::IK_CXX));
clang::PreprocessorOptions& preprocessorOpts = ci.getPreprocessorOpts();
preprocessorOpts.clearRemappedFiles();
preprocessorOpts.addRemappedFile(Filename, MB.release());
// Execute
clang::SyntaxOnlyAction Act;
if (Act.BeginSourceFile(ci, ci.getFrontendOpts().Inputs[0])) {
Act.Execute();
Act.EndSourceFile();
}
}
The output contains COMPLETION: 50 Decl : MyFoo : [#void#]MyFoo() .
I get this answer from code segment
PreprocessorOpts.clearRemappedFiles();
PreprocessorOpts.RetainRemappedFileBuffers = true;
for (const auto &RemappedFile : RemappedFiles) {
PreprocessorOpts.addRemappedFile(RemappedFile.first, RemappedFile.second);
OwnedBuffers.push_back(RemappedFile.second);
}
in ASTUnit::CodeComplete .
I believe you may want to read AugmentedCodeCompleteConsumer to make use of those completion hints.