https://github.com/ChuanqiXu9 created https://github.com/llvm/llvm-project/pull/102423
Close https://github.com/llvm/llvm-project/issues/102360 Close https://github.com/llvm/llvm-project/issues/102349 http://eel.is/c++draft/basic.def.odr#15.3 makes it clear that the duplicated deinition are not allowed to be attached to named modules. But we need to filter the implicit declarations as user can do nothing about it and the diagnostic message is annoying. >From 7ad4017be6b6053784311aff06a14e228830f209 Mon Sep 17 00:00:00 2001 From: Chuanqi Xu <yedeng...@linux.alibaba.com> Date: Thu, 8 Aug 2024 12:47:32 +0800 Subject: [PATCH] [C++20] [Modules] Don't diagnose duplicated implicit decl in multiple named modules Close https://github.com/llvm/llvm-project/issues/102360 Close https://github.com/llvm/llvm-project/issues/102349 http://eel.is/c++draft/basic.def.odr#15.3 makes it clear that the duplicated deinition are not allowed to be attached to named modules. But we need to filter the implicit declarations as user can do nothing about it and the diagnostic message is annoying. --- clang/lib/Serialization/ASTReaderDecl.cpp | 65 +++++++++++++++++------ clang/test/Modules/pr102349.cppm | 52 ++++++++++++++++++ clang/test/Modules/pr102360.cppm | 53 ++++++++++++++++++ 3 files changed, 154 insertions(+), 16 deletions(-) create mode 100644 clang/test/Modules/pr102349.cppm create mode 100644 clang/test/Modules/pr102360.cppm diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp index 0ced5f9290408..10599849b69bc 100644 --- a/clang/lib/Serialization/ASTReaderDecl.cpp +++ b/clang/lib/Serialization/ASTReaderDecl.cpp @@ -3684,6 +3684,54 @@ static void inheritDefaultTemplateArguments(ASTContext &Context, } } +// [basic.link]/p10: +// If two declarations of an entity are attached to different modules, +// the program is ill-formed; +static void checkMultipleDefinitionInNamedModules(ASTReader &Reader, Decl *D, + Decl *Previous) { + Module *M = Previous->getOwningModule(); + + // We only care about the case in named modules. + if (!M || !M->isNamedModule()) + return; + + // If it is previous implcitly introduced, it is not meaningful to + // diagnose it. + if (Previous->isImplicit()) + return; + + // FIXME: Get rid of the enumeration of decl types once we have an appropriate + // abstract for decls of an entity. e.g., the namespace decl and using decl + // doesn't introduce an entity. + if (!isa<VarDecl, FunctionDecl, TagDecl, RedeclarableTemplateDecl>(Previous)) + return; + + // Skip implicit instantiations since it may give false positive diagnostic + // messages. + // FIXME: Maybe this shows the implicit instantiations may have incorrect + // module owner ships. But given we've finished the compilation of a module, + // how can we add new entities to that module? + if (auto *VTSD = dyn_cast<VarTemplateSpecializationDecl>(Previous); + VTSD && !VTSD->isExplicitSpecialization()) + return; + if (auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(Previous); + CTSD && !CTSD->isExplicitSpecialization()) + return; + if (auto *Func = dyn_cast<FunctionDecl>(Previous)) + if (auto *FTSI = Func->getTemplateSpecializationInfo(); + FTSI && !FTSI->isExplicitSpecialization()) + return; + + // It is fine if they are in the same module. + if (Reader.getContext().isInSameModule(M, D->getOwningModule())) + return; + + Reader.Diag(Previous->getLocation(), + diag::err_multiple_decl_in_different_modules) + << cast<NamedDecl>(Previous) << M->Name; + Reader.Diag(D->getLocation(), diag::note_also_found); +} + void ASTDeclReader::attachPreviousDecl(ASTReader &Reader, Decl *D, Decl *Previous, Decl *Canon) { assert(D && Previous); @@ -3697,22 +3745,7 @@ void ASTDeclReader::attachPreviousDecl(ASTReader &Reader, Decl *D, #include "clang/AST/DeclNodes.inc" } - // [basic.link]/p10: - // If two declarations of an entity are attached to different modules, - // the program is ill-formed; - // - // FIXME: Get rid of the enumeration of decl types once we have an appropriate - // abstract for decls of an entity. e.g., the namespace decl and using decl - // doesn't introduce an entity. - if (Module *M = Previous->getOwningModule(); - M && M->isNamedModule() && - isa<VarDecl, FunctionDecl, TagDecl, RedeclarableTemplateDecl>(Previous) && - !Reader.getContext().isInSameModule(M, D->getOwningModule())) { - Reader.Diag(Previous->getLocation(), - diag::err_multiple_decl_in_different_modules) - << cast<NamedDecl>(Previous) << M->Name; - Reader.Diag(D->getLocation(), diag::note_also_found); - } + checkMultipleDefinitionInNamedModules(Reader, D, Previous); // If the declaration was visible in one module, a redeclaration of it in // another module remains visible even if it wouldn't be visible by itself. diff --git a/clang/test/Modules/pr102349.cppm b/clang/test/Modules/pr102349.cppm new file mode 100644 index 0000000000000..2d166c9e93fcf --- /dev/null +++ b/clang/test/Modules/pr102349.cppm @@ -0,0 +1,52 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t +// RUN: split-file %s %t +// +// RUN: %clang_cc1 -std=c++20 %t/a.cppm -emit-module-interface -o %t/a.pcm +// RUN: %clang_cc1 -std=c++20 %t/b.cppm -emit-module-interface -o %t/b.pcm \ +// RUN: -fprebuilt-module-path=%t +// RUN: %clang_cc1 -std=c++20 %t/c.cppm -emit-module-interface -o %t/c.pcm \ +// RUN: -fprebuilt-module-path=%t +// RUN: %clang_cc1 -std=c++20 %t/d.cpp -fsyntax-only -verify \ +// RUN: -fprebuilt-module-path=%t + +//--- a.cppm +export module a; + +export template<typename> +struct a; + +template<typename> +struct a { +}; + +export template<typename T> +constexpr auto aa = a<T>(); + +//--- b.cppm +export module b; + +import a; + +static void b() { + static_cast<void>(a<void>()); +} + +//--- c.cppm +export module c; + +import a; + +static void c() { + static_cast<void>(aa<void>); +} + +//--- d.cpp +// expected-no-diagnostics +import a; +import b; +import c; + +static void d() { + static_cast<void>(a<void>()); +} diff --git a/clang/test/Modules/pr102360.cppm b/clang/test/Modules/pr102360.cppm new file mode 100644 index 0000000000000..e0dab1a031801 --- /dev/null +++ b/clang/test/Modules/pr102360.cppm @@ -0,0 +1,53 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t +// RUN: split-file %s %t +// +// RUN: %clang_cc1 -std=c++20 %t/a.cppm -emit-module-interface -o %t/a.pcm +// RUN: %clang_cc1 -std=c++20 %t/b.cppm -emit-module-interface -o %t/b.pcm \ +// RUN: -fprebuilt-module-path=%t +// RUN: %clang_cc1 -std=c++20 %t/c.cppm -emit-module-interface -o %t/c.pcm \ +// RUN: -fprebuilt-module-path=%t +// RUN: %clang_cc1 -std=c++20 %t/d.cpp -fsyntax-only -verify \ +// RUN: -fprebuilt-module-path=%t + +//--- a.cppm +export module a; + +template<typename> +constexpr auto impl = true; + +export template<typename T> +void a() { +} + +export template<typename T> requires impl<T> +void a() { +} + +//--- b.cppm +export module b; + +import a; + +static void b() { + a<void>(); +} + +//--- c.cppm +export module c; + +import a; + +static void c() { + a<void>(); +} + +//--- d.cpp +// expected-no-diagnostics +import a; +import b; +import c; + +static void d() { + a<void>(); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
