以下是相关代码：

llvm::LLVMContext c;
clang::CompilerInstance CI;
llvm::Module m("",c);
clang::EmitLLVMOnlyAction emit(&c);
emit.setLinkModule(&m);

std::string errors;
llvm::raw_string_ostream error_stream(errors);
clang::DiagnosticOptions diagopts;
clang::TextDiagnosticPrinter printer(error_stream,&diagopts);
llvm::IntrusiveRefCntPtr<clang::DiagnosticIDs> diagids(new clang::DiagnosticIDs);
clang::DiagnosticsEngine engine(diagids,&diagopts,&printer,false);
CI.setDiagnostics(&engine);

clang::TargetOptions target;
target.Triple = llvm::sys::getDefaultTargetTriple();
CI.setTarget(clang::TargetInfo::CreateTargetInfo(engine,&target));

CI.getLangOpts().CPlusPlus0x = true;
CI.getLangOpts().CPlusPlus = true;

clang::FrontendInputFile f("main.cpp",clang::InputKind::IK_CXX,true);
emit.BeginSourceFile(CI,f);

emit.Execute();
auto sema = CI.takeSema();
auto ast = &CI.getASTContext();
CI.resetAndLeakASTContext();
emit.EndSourceFile();

emit.takeModule();
auto identinfo = CI.getPreprocessor().getIdentifierInfo("WriteConsoleW");

auto sloc = CI.getSourceManager().getLocForEndOfFile(CI.getSourceManager().translateFile(CI.getFileManager().getFile("main.cpp")));
clang::LookupResult lr(*sema,clang::DeclarationName(identinfo),sloc,clang::Sema::LookupNameKind::LookupOrdinaryName);
auto result = sema->LookupName(lr,sema->TUScope);

我已经验证了identinfo不为NULL,并且该sloc也不为零.

为什么不能找到我的名字？

编辑：我已经成功地在全局范围内执行限定名称查找.不幸的是,这与执行不合格的名称查找不同 – 例如,没有ADL. Clang仍然坚持认为不存在不合格的函数名称.

编辑：合格的代码是类似但重构的,以避免对Frontend库的依赖,因为它具有非常有问题的所有权语义,并且该操作不会做我所需要的.

clang::CompilerInstance ci;
clang::FileSystemOptions fso;
clang::FileManager fm(fso);

std::string errors;
llvm::raw_string_ostream error_stream(errors);
clang::DiagnosticOptions diagopts;

llvm::IntrusiveRefCntPtr<clang::DiagnosticIDs> diagids(new clang::DiagnosticIDs);
clang::DiagnosticsEngine engine(diagids,new clang::TextDiagnosticPrinter(error_stream,&diagopts),false);

clang::SourceManager sm(engine,fm);

clang::LangOptions langopts;
langopts.CPlusPlus = true;
langopts.CPlusPlus0x = true;

clang::TargetOptions target;
target.Triple = llvm::sys::getDefaultTargetTriple();
auto targetinfo = clang::TargetInfo::CreateTargetInfo(engine,&target);

auto headeropts = llvm::IntrusiveRefCntPtr<clang::HeaderSearchOptions>(new clang::HeaderSearchOptions());
clang::HeaderSearch hs(headeropts,fm,engine,langopts,targetinfo);

auto x = llvm::IntrusiveRefCntPtr<clang::PreprocessorOptions>(new clang::PreprocessorOptions());
clang::Preprocessor p(x,targetinfo,sm,hs,ci);

clang::ASTContext astcon(langopts,p.getIdentifierTable(),p.getSelectorTable(),p.getBuiltinInfo(),1000);
clang::CodeGenOptions codegenopts;
clang::CodeGen::CodeGenModule codegen(astcon,codegenopts,m,llvm::DataLayout(&m),engine);
CodeGenConsumer consumer(&codegen);
clang::Sema sema(p,astcon,consumer,clang::TranslationUnitKind::TU_Prefix);

sm.createMainFileID(fm.getFile(filepath));
engine.getClient()->BeginSourceFile(langopts,&p);
clang::ParseAST(sema);
codegen.Release();
engine.getClient()->EndSourceFile();
    /*
for (auto it = astcon.getTranslationUnitDecl()->decls_begin(); it != astcon.getTranslationUnitDecl()->decls_end(); ++it) {
    if (auto named = llvm::dyn_cast<clang::NamedDecl>(*it)) {
        std::cout << named->getNameAsString() << "\n";
    }
}*/
clang::LookupResult lr(sema,clang::DeclarationName(p.getIdentifierInfo("f")),sm.getLocForEndOfFile(sm.translateFile(fm.getFile(filepath))),clang::Sema::LookupNameKind::LookupOrdinaryName);
auto result = sema.LookupQualifiedName(lr,astcon.getTranslationUnitDecl());