pub const CrtBasenames = struct {
    crt0: ?[]const u8 = null,
    crti: ?[]const u8 = null,
    crtbegin: ?[]const u8 = null,
    crtend: ?[]const u8 = null,
    crtn: ?[]const u8 = null,

    pub const GetArgs = struct {
        target: std.Target,
        link_libc: bool,
        output_mode: std.builtin.OutputMode,
        link_mode: std.builtin.LinkMode,
        pie: bool,
    };

    /// Determine file system path names of C runtime startup objects for supported
    /// link modes.
    pub fn get(args: GetArgs) CrtBasenames {
        // crt objects are only required for libc.
        if (!args.link_libc) return .{};

        // Flatten crt cases.
        const mode: enum {
            dynamic_lib,
            dynamic_exe,
            dynamic_pie,
            static_exe,
            static_pie,
        } = switch (args.output_mode) {
            .Obj => return .{},
            .Lib => switch (args.link_mode) {
                .dynamic => .dynamic_lib,
                .static => return .{},
            },
            .Exe => switch (args.link_mode) {
                .dynamic => if (args.pie) .dynamic_pie else .dynamic_exe,
                .static => if (args.pie) .static_pie else .static_exe,
            },
        };

        const target = args.target;

        if (target.abi.isAndroid()) return switch (mode) {
            .dynamic_lib => .{
                .crtbegin = "crtbegin_so.o",
                .crtend = "crtend_so.o",
            },
            .dynamic_exe, .dynamic_pie => .{
                .crtbegin = "crtbegin_dynamic.o",
                .crtend = "crtend_android.o",
            },
            .static_exe, .static_pie => .{
                .crtbegin = "crtbegin_static.o",
                .crtend = "crtend_android.o",
            },
        };

        return switch (target.os.tag) {
            .linux => switch (mode) {
                .dynamic_lib => .{
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
                .dynamic_exe => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
                .dynamic_pie => .{
                    .crt0 = "Scrt1.o",
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
                .static_exe => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
                .static_pie => .{
                    .crt0 = "rcrt1.o",
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
            },
            .dragonfly => switch (mode) {
                .dynamic_lib => .{
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .dynamic_exe => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .dynamic_pie => .{
                    .crt0 = "Scrt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .static_exe => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .static_pie => .{
                    .crt0 = "Scrt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
            },
            .freebsd => switch (mode) {
                .dynamic_lib => .{
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .dynamic_exe => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .dynamic_pie => .{
                    .crt0 = "Scrt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .static_exe => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginT.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .static_pie => .{
                    .crt0 = "Scrt1.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
            },
            .netbsd => switch (mode) {
                .dynamic_lib => .{
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .dynamic_exe => .{
                    .crt0 = "crt0.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .dynamic_pie => .{
                    .crt0 = "crt0.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .static_exe => .{
                    .crt0 = "crt0.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginT.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .static_pie => .{
                    .crt0 = "crt0.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginT.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
            },
            .openbsd => switch (mode) {
                .dynamic_lib => .{
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                },
                .dynamic_exe, .dynamic_pie => .{
                    .crt0 = "crt0.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                },
                .static_exe, .static_pie => .{
                    .crt0 = "rcrt0.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                },
            },
            .haiku => switch (mode) {
                .dynamic_lib => .{
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .dynamic_exe => .{
                    .crt0 = "start_dyn.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .dynamic_pie => .{
                    .crt0 = "start_dyn.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
                .static_exe => .{
                    .crt0 = "start_dyn.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbegin.o",
                    .crtend = "crtend.o",
                    .crtn = "crtn.o",
                },
                .static_pie => .{
                    .crt0 = "start_dyn.o",
                    .crti = "crti.o",
                    .crtbegin = "crtbeginS.o",
                    .crtend = "crtendS.o",
                    .crtn = "crtn.o",
                },
            },
            .solaris, .illumos => switch (mode) {
                .dynamic_lib => .{
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
                .dynamic_exe, .dynamic_pie => .{
                    .crt0 = "crt1.o",
                    .crti = "crti.o",
                    .crtn = "crtn.o",
                },
                .static_exe, .static_pie => .{},
            },
            else => .{},
        };
    }
}