llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-modules Author: Chuanqi Xu (ChuanqiXu9) <details> <summary>Changes</summary> Recently, there are multiple false positive issue reports about the reachability of implementation partition units: - https://github.com/llvm/llvm-project/issues/105882 - https://github.com/llvm/llvm-project/issues/101348 - https://lists.isocpp.org/core/2024/08/16232.php And according to our use experience for modules, we find it is a pretty good practice to not import implementation partition units in the interface units. It can help developers to have a pretty good mental model for when to use an implementation partition unit: that any unit in the module but not in the module interfaces can be in the implementation partition unit. So I think it is good to add the diagnostics. --- Full diff: https://github.com/llvm/llvm-project/pull/108493.diff 4 Files Affected: - (modified) clang/include/clang/Basic/DiagnosticSemaKinds.td (+3) - (modified) clang/lib/Sema/SemaModule.cpp (+5) - (modified) clang/test/CXX/module/module.import/p2.cpp (+1-2) - (modified) clang/test/Modules/cxx20-10-3-ex1.cpp (+1) ``````````diff diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index efdc058edca56d..7545a06123789d 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -439,6 +439,9 @@ def warn_deprecated_literal_operator_id: Warning< "is deprecated">, InGroup<DeprecatedLiteralOperator>, DefaultIgnore; def warn_reserved_module_name : Warning< "%0 is a reserved name for a module">, InGroup<ReservedModuleIdentifier>; +def warn_import_implementation_partition_unit_in_interface_unit : Warning< + "it is not suggested to import implementation partition unit in interface unit">, + InGroup<DiagGroup<"import-implementation-partition-unit-in-interface-unit">>; def warn_parameter_size: Warning< "%0 is a large (%1 bytes) pass-by-value argument; " diff --git a/clang/lib/Sema/SemaModule.cpp b/clang/lib/Sema/SemaModule.cpp index 3b84e7bd4277fd..5748906748a44e 100644 --- a/clang/lib/Sema/SemaModule.cpp +++ b/clang/lib/Sema/SemaModule.cpp @@ -650,6 +650,11 @@ DeclResult Sema::ActOnModuleImport(SourceLocation StartLoc, else VisibleModules.setVisible(Mod, ImportLoc); + assert((!Mod->isModulePartitionImplementation() || getCurrentModule()) && + "We can only import a partition unit in a named module."); + if (Mod->isModulePartitionImplementation() && getCurrentModule()->isModuleInterfaceUnit()) + Diag(ImportLoc, diag::warn_import_implementation_partition_unit_in_interface_unit); + checkModuleImportContext(*this, Mod, ImportLoc, CurContext); // FIXME: we should support importing a submodule within a different submodule diff --git a/clang/test/CXX/module/module.import/p2.cpp b/clang/test/CXX/module/module.import/p2.cpp index ef6006811e7763..3ac76856c7cfc3 100644 --- a/clang/test/CXX/module/module.import/p2.cpp +++ b/clang/test/CXX/module/module.import/p2.cpp @@ -30,9 +30,8 @@ void test() { } //--- UseInPartA.cppm -// expected-no-diagnostics export module M:partA; -import :impl; +import :impl; // expected-warning {{it is not suggested to import implementation partition unit in interface unit}} void test() { A a; } diff --git a/clang/test/Modules/cxx20-10-3-ex1.cpp b/clang/test/Modules/cxx20-10-3-ex1.cpp index 99b88c7e442ffd..dcdc92340366ae 100644 --- a/clang/test/Modules/cxx20-10-3-ex1.cpp +++ b/clang/test/Modules/cxx20-10-3-ex1.cpp @@ -37,6 +37,7 @@ module M:PartImpl; export module M; // error: exported partition :Part is an implementation unit export import :PartImpl; // expected-error {{module partition implementations cannot be exported}} + // expected-warning@-1 {{it is not suggested to import implementation partition unit in interface unit}} //--- std10-3-ex1-tu3.cpp export module M:Part; `````````` </details> https://github.com/llvm/llvm-project/pull/108493 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
