https://github.com/mjklemm created https://github.com/llvm/llvm-project/pull/74139
This is related to PR #74120 and (merged) PR #73124. This PR adds the `-fno-fortran-main` command line option to remove `Fortran_main.a` from the link and to allow for linking Fortran code w/o program unit with C/C++ translation units that provide the `main()` entrypoint. >From 2e41335a7de3d2efa88eacee659172a3b9525e45 Mon Sep 17 00:00:00 2001 From: Michael Klemm <michael.kl...@amd.com> Date: Fri, 1 Dec 2023 21:41:44 +0100 Subject: [PATCH 1/2] Add -fno-fortran-main driver option --- clang/include/clang/Driver/Options.td | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 19d04e82aed4d68..aa26344f67b3132 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -6345,6 +6345,10 @@ def J : JoinedOrSeparate<["-"], "J">, Group<gfortran_Group>, Alias<module_dir>; +def no_fortran_main : Flag<["-"], "fno-fortran-main">, + Visibility<[FlangOption]>, Group<f_Group>, + HelpText<"Don't link in Fortran main">; + //===----------------------------------------------------------------------===// // FC1 Options //===----------------------------------------------------------------------===// >From 44b684ae43a6da37bb56c5b699628c6807257ad9 Mon Sep 17 00:00:00 2001 From: Michael Klemm <michael.kl...@amd.com> Date: Fri, 1 Dec 2023 21:42:09 +0100 Subject: [PATCH 2/2] Skip linking Fortran_main.a if -fno-fortran-main is present --- clang/lib/Driver/ToolChains/CommonArgs.cpp | 46 ++++++++++++---------- 1 file changed, 25 insertions(+), 21 deletions(-) diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp index 0ae8e2dce32e94a..2899f07cb7490ca 100644 --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp @@ -1116,33 +1116,37 @@ bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC, return true; } +// TODO: add -fno-fortran-main option and check it in this function. void tools::addFortranRuntimeLibs(const ToolChain &TC, const ArgList &Args, llvm::opt::ArgStringList &CmdArgs) { // These are handled earlier on Windows by telling the frontend driver to add // the correct libraries to link against as dependents in the object file. if (!TC.getTriple().isKnownWindowsMSVCEnvironment()) { - // The --whole-archive option needs to be part of the link line to - // make sure that the main() function from Fortran_main.a is pulled - // in by the linker. Determine if --whole-archive is active when - // flang will try to link Fortran_main.a. If it is, don't add the - // --whole-archive flag to the link line. If it's not, add a proper - // --whole-archive/--no-whole-archive bracket to the link line. - bool WholeArchiveActive = false; - for (auto *Arg : Args.filtered(options::OPT_Wl_COMMA)) - if (Arg) - for (StringRef ArgValue : Arg->getValues()) { - if (ArgValue == "--whole-archive") - WholeArchiveActive = true; - if (ArgValue == "--no-whole-archive") - WholeArchiveActive = false; - } - - if (!WholeArchiveActive) - CmdArgs.push_back("--whole-archive"); - CmdArgs.push_back("-lFortran_main"); - if (!WholeArchiveActive) - CmdArgs.push_back("--no-whole-archive"); + // if -fno-fortran-main has been passed, skip linking Fortran_main.a + bool DontLinkFortranMain = Args.getLastArg(options::OPT_no_fortran_main) != nullptr; + if (!DontLinkFortranMain) { + // The --whole-archive option needs to be part of the link line to + // make sure that the main() function from Fortran_main.a is pulled + // in by the linker. Determine if --whole-archive is active when + // flang will try to link Fortran_main.a. If it is, don't add the + // --whole-archive flag to the link line. If it's not, add a proper + // --whole-archive/--no-whole-archive bracket to the link line. + bool WholeArchiveActive = false; + for (auto *Arg : Args.filtered(options::OPT_Wl_COMMA)) + if (Arg) + for (StringRef ArgValue : Arg->getValues()) { + if (ArgValue == "--whole-archive") + WholeArchiveActive = true; + if (ArgValue == "--no-whole-archive") + WholeArchiveActive = false; + } + if (!WholeArchiveActive) + CmdArgs.push_back("--whole-archive"); + CmdArgs.push_back("-lFortran_main"); + if (!WholeArchiveActive) + CmdArgs.push_back("--no-whole-archive"); + } // Perform regular linkage of the remaining runtime libraries. CmdArgs.push_back("-lFortranRuntime"); CmdArgs.push_back("-lFortranDecimal"); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits