Author: Nathan Sidwell Date: 2021-12-21T10:29:01-05:00 New Revision: d4de2a4d5905beb0602a615593daf003378ddb64
URL: https://github.com/llvm/llvm-project/commit/d4de2a4d5905beb0602a615593daf003378ddb64 DIFF: https://github.com/llvm/llvm-project/commit/d4de2a4d5905beb0602a615593daf003378ddb64.diff LOG: [clang][NFC] Refactor coroutine_traits lookup To allow transition from the TS-specified std::experimental::coroutine_traits to the C++20-specified std::coroutine_traits, we lookup in both places and provide helpful diagnostics. This refactors the code to avoid separate paths to std::experimental lookups. Reviewed By: ChuanqiXu Differential Revision: https://reviews.llvm.org/D116029 Added: Modified: clang/lib/Sema/SemaCoroutine.cpp Removed: ################################################################################ diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp index d4a919e8c1656..27ba49fb001c0 100644 --- a/clang/lib/Sema/SemaCoroutine.cpp +++ b/clang/lib/Sema/SemaCoroutine.cpp @@ -1661,45 +1661,53 @@ ClassTemplateDecl *Sema::lookupCoroutineTraits(SourceLocation KwLoc, SourceLocation FuncLoc, NamespaceDecl *&Namespace) { if (!StdCoroutineTraitsCache) { - NamespaceDecl *CoroNamespace = getStdNamespace(); - LookupResult Result(*this, &PP.getIdentifierTable().get("coroutine_traits"), - FuncLoc, LookupOrdinaryName); - - if (!CoroNamespace || !LookupQualifiedName(Result, CoroNamespace)) { - /// Look up in namespace std::experimental, for compatibility. - /// TODO: Remove this extra lookup when <experimental/coroutine> is - /// removed. - CoroNamespace = lookupStdExperimentalNamespace(); - if (!CoroNamespace || !LookupQualifiedName(Result, CoroNamespace)) { - Diag(KwLoc, diag::err_implied_coroutine_type_not_found) - << "std::coroutine_traits"; - return nullptr; - } + // Because coroutines moved from std::experimental in the TS to std in + // C++20, we look in both places to give users time to transition their + // TS-specific code to C++20. Diagnostics are given when the TS usage is + // discovered. + // TODO: Become stricter when <experimental/coroutine> is removed. + + auto const &TraitIdent = PP.getIdentifierTable().get("coroutine_traits"); + + NamespaceDecl *StdSpace = getStdNamespace(); + LookupResult ResStd(*this, &TraitIdent, FuncLoc, LookupOrdinaryName); + bool InStd = StdSpace && LookupQualifiedName(ResStd, StdSpace); + + NamespaceDecl *ExpSpace = lookupStdExperimentalNamespace(); + LookupResult ResExp(*this, &TraitIdent, FuncLoc, LookupOrdinaryName); + bool InExp = ExpSpace && LookupQualifiedName(ResExp, ExpSpace); + + if (!InStd && !InExp) { + // The goggles, they found nothing! + Diag(KwLoc, diag::err_implied_coroutine_type_not_found) + << "std::coroutine_traits"; + return nullptr; + } + + if (!InStd) { + // Found only in std::experimental. Diag(KwLoc, diag::warn_deprecated_coroutine_namespace) << "coroutine_traits"; - } else { - /// When we found coroutine_traits in std namespace. Make sure there is no - /// misleading definition in std::experimental namespace. - NamespaceDecl *ExpNamespace = lookupStdExperimentalNamespace(); - LookupResult ExpResult(*this, - &PP.getIdentifierTable().get("coroutine_traits"), - FuncLoc, LookupOrdinaryName); - if (ExpNamespace && LookupQualifiedName(ExpResult, ExpNamespace)) { - Diag(KwLoc, - diag::err_mixed_use_std_and_experimental_namespace_for_coroutine); - Diag(KwLoc, diag::warn_deprecated_coroutine_namespace) - << "coroutine_traits"; - return nullptr; - } + } else if (InExp) { + // Found in std and std::experimental. + Diag(KwLoc, + diag::err_mixed_use_std_and_experimental_namespace_for_coroutine); + Diag(KwLoc, diag::warn_deprecated_coroutine_namespace) + << "coroutine_traits"; + return nullptr; } + // Prefer ::std to std::experimental. + auto &Result = InStd ? ResStd : ResExp; + CoroTraitsNamespaceCache = InStd ? StdSpace : ExpSpace; + + // coroutine_traits is required to be a class template. if (!(StdCoroutineTraitsCache = Result.getAsSingle<ClassTemplateDecl>())) { Result.suppressDiagnostics(); NamedDecl *Found = *Result.begin(); Diag(Found->getLocation(), diag::err_malformed_std_coroutine_traits); return nullptr; } - CoroTraitsNamespaceCache = CoroNamespace; } Namespace = CoroTraitsNamespaceCache; return StdCoroutineTraitsCache; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
