https://github.com/ashwinbanwari updated https://github.com/llvm/llvm-project/pull/146461
>From 845f99834c6c9a78c05396a0337051273b1ae138 Mon Sep 17 00:00:00 2001 From: Ashwin Banwari <ashwinkbanw...@gmail.com> Date: Mon, 30 Jun 2025 20:45:39 -0700 Subject: [PATCH 1/6] Implement P3618R0 --- clang/docs/ReleaseNotes.rst | 2 ++ clang/include/clang/Basic/DiagnosticSemaKinds.td | 2 +- clang/lib/Sema/SemaDecl.cpp | 9 +++------ clang/test/SemaCXX/modules.cppm | 2 ++ libcxx/utils/libcxx/test/features.py | 2 +- 5 files changed, 9 insertions(+), 8 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index e6c8f9df22170..33dd07179aeea 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -135,6 +135,8 @@ C++2c Feature Support - Implemented `P2719R4 Type-aware allocation and deallocation functions <https://wg21.link/P2719>`_. +- Implemented `P3618R0 Allow attaching main to the global module<https://wg21.link/P3618>`_. + C++23 Feature Support ^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 5062505cf3c01..d5d982d20eaa5 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -1086,7 +1086,7 @@ def ext_main_used : Extension< "referring to 'main' within an expression is a Clang extension">, InGroup<Main>; def ext_main_invalid_linkage_specification : ExtWarn< "'main' should not be " - "'extern \"%select{C|C++}0\"'">, InGroup<Main>; + "'extern \"C\"'">, InGroup<Main>; /// parser diagnostics def ext_no_declarators : ExtWarn<"declaration does not declare anything">, diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp index a34e2c9cbb003..61b82b8377e22 100644 --- a/clang/lib/Sema/SemaDecl.cpp +++ b/clang/lib/Sema/SemaDecl.cpp @@ -12400,12 +12400,9 @@ bool Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD, void Sema::CheckMain(FunctionDecl *FD, const DeclSpec &DS) { // [basic.start.main]p3 - // The main function shall not be declared with a linkage-specification. - if (FD->isExternCContext() || - (FD->isExternCXXContext() && - FD->getDeclContext()->getRedeclContext()->isTranslationUnit())) - Diag(FD->getLocation(), diag::ext_main_invalid_linkage_specification) - << FD->getLanguageLinkage(); + // The main function shall not be declared with C linkage-specification. + if (FD->isExternCContext()) + Diag(FD->getLocation(), diag::ext_main_invalid_linkage_specification); // C++11 [basic.start.main]p3: // A program that [...] declares main to be inline, static or diff --git a/clang/test/SemaCXX/modules.cppm b/clang/test/SemaCXX/modules.cppm index 5d0d6da44a2ed..ddbbc7cd86360 100644 --- a/clang/test/SemaCXX/modules.cppm +++ b/clang/test/SemaCXX/modules.cppm @@ -68,6 +68,8 @@ int n; //--- test3.cpp export module bar; +extern "C++" int main() {} + static int m; int n; diff --git a/libcxx/utils/libcxx/test/features.py b/libcxx/utils/libcxx/test/features.py index 74746e37d3bc4..a479ea48ac810 100644 --- a/libcxx/utils/libcxx/test/features.py +++ b/libcxx/utils/libcxx/test/features.py @@ -340,7 +340,7 @@ def _mingwSupportsModules(cfg): cfg, """ export module test; - int main(int, char**) { return 0; } + extern "C++" int main(int, char**) { return 0; } """, ), ), >From 70afaf39fb597d7d0ae50e7bf20bc3fa3d28e848 Mon Sep 17 00:00:00 2001 From: Ashwin Banwari <ashwinkbanw...@gmail.com> Date: Mon, 30 Jun 2025 20:48:19 -0700 Subject: [PATCH 2/6] typo --- clang/docs/ReleaseNotes.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 33dd07179aeea..9877b0e651596 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -135,7 +135,7 @@ C++2c Feature Support - Implemented `P2719R4 Type-aware allocation and deallocation functions <https://wg21.link/P2719>`_. -- Implemented `P3618R0 Allow attaching main to the global module<https://wg21.link/P3618>`_. +- Implemented `P3618R0 Allow attaching main to the global module <https://wg21.link/P3618>`_. C++23 Feature Support ^^^^^^^^^^^^^^^^^^^^^ >From 880f14b1773c3064151e695a526127b79dc22db0 Mon Sep 17 00:00:00 2001 From: Ashwin Banwari <ashwinkbanw...@gmail.com> Date: Mon, 30 Jun 2025 20:48:50 -0700 Subject: [PATCH 3/6] clang-format --- clang/include/clang/Basic/DiagnosticSemaKinds.td | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index d5d982d20eaa5..6e48f3bc88bab 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -1084,9 +1084,9 @@ def warn_main_redefined : Warning<"variable named 'main' with external linkage " "has undefined behavior">, InGroup<Main>; def ext_main_used : Extension< "referring to 'main' within an expression is a Clang extension">, InGroup<Main>; -def ext_main_invalid_linkage_specification : ExtWarn< - "'main' should not be " - "'extern \"C\"'">, InGroup<Main>; +def ext_main_invalid_linkage_specification : ExtWarn<"'main' should not be " + "'extern \"C\"'">, + InGroup<Main>; /// parser diagnostics def ext_no_declarators : ExtWarn<"declaration does not declare anything">, >From fd91a7279ac8bf2109e7a6fc3f0e7fa745176289 Mon Sep 17 00:00:00 2001 From: Ashwin Banwari <ashwinkbanw...@gmail.com> Date: Mon, 30 Jun 2025 21:24:22 -0700 Subject: [PATCH 4/6] fix libcxx test --- libcxx/utils/libcxx/test/features.py | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/libcxx/utils/libcxx/test/features.py b/libcxx/utils/libcxx/test/features.py index a479ea48ac810..7e16a9b69fda8 100644 --- a/libcxx/utils/libcxx/test/features.py +++ b/libcxx/utils/libcxx/test/features.py @@ -336,13 +336,20 @@ def _mingwSupportsModules(cfg): or platform.system().lower().startswith("aix") # Avoid building on platforms that don't support modules properly. or not hasCompileFlag(cfg, "-Wno-reserved-module-identifier") - or not sourceBuilds( + # older versions don't support extern "C++", newer versions don't support main in named module. + or not (sourceBuilds( cfg, """ export module test; extern "C++" int main(int, char**) { return 0; } """, - ), + ) or sourceBuilds( + cfg, + """ + export module test; + int main(int, char**) { return 0; } + """, + )), ), # The time zone validation tests compare the output of zdump against the # output generated by <chrono>'s time zone support. >From 035592a9ba9098f0153b38af191d3beb2ac14605 Mon Sep 17 00:00:00 2001 From: Ashwin Banwari <ashwinkbanw...@gmail.com> Date: Mon, 30 Jun 2025 21:46:42 -0700 Subject: [PATCH 5/6] darker format --- libcxx/utils/libcxx/test/features.py | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/libcxx/utils/libcxx/test/features.py b/libcxx/utils/libcxx/test/features.py index 7e16a9b69fda8..c478d99fbed00 100644 --- a/libcxx/utils/libcxx/test/features.py +++ b/libcxx/utils/libcxx/test/features.py @@ -337,19 +337,22 @@ def _mingwSupportsModules(cfg): # Avoid building on platforms that don't support modules properly. or not hasCompileFlag(cfg, "-Wno-reserved-module-identifier") # older versions don't support extern "C++", newer versions don't support main in named module. - or not (sourceBuilds( - cfg, - """ + or not ( + sourceBuilds( + cfg, + """ export module test; extern "C++" int main(int, char**) { return 0; } """, - ) or sourceBuilds( - cfg, - """ + ) + or sourceBuilds( + cfg, + """ export module test; int main(int, char**) { return 0; } """, - )), + ) + ), ), # The time zone validation tests compare the output of zdump against the # output generated by <chrono>'s time zone support. >From bf5dd7036bf6c369a4a3c26b2d8679280e780204 Mon Sep 17 00:00:00 2001 From: Ashwin Banwari <ashwinkbanw...@gmail.com> Date: Mon, 30 Jun 2025 21:52:50 -0700 Subject: [PATCH 6/6] fix p3 test --- clang/test/CXX/basic/basic.start/basic.start.main/p3.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/clang/test/CXX/basic/basic.start/basic.start.main/p3.cpp b/clang/test/CXX/basic/basic.start/basic.start.main/p3.cpp index 497a9328c1156..a8cd523b0837f 100644 --- a/clang/test/CXX/basic/basic.start/basic.start.main/p3.cpp +++ b/clang/test/CXX/basic/basic.start/basic.start.main/p3.cpp @@ -102,11 +102,12 @@ namespace ns { } #elif TEST13 +// expected-no-diagnostics extern "C++" { - int main(); // expected-warning {{'main' should not be 'extern "C++"'}} + int main(); } -extern "C++" int main(); // expected-warning {{'main' should not be 'extern "C++"'}} +extern "C++" int main(); namespace ns1 { extern "C++" int main(); // ok _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
