zig/lib/std/target.zig

const std = @import("std.zig");
const mem = std.mem;
const builtin = std.builtin;
const Version = std.builtin.Version;

/// TODO Nearly all the functions in this namespace would be
/// better off if https://github.com/ziglang/zig/issues/425
/// was solved.
pub const Target = struct {
    cpu: Cpu,
    os: Os,
    abi: Abi,

    pub const Os = struct {
        tag: Tag,
        version_range: VersionRange,

        pub const Tag = enum {
            freestanding,
            ananas,
            cloudabi,
            dragonfly,
            freebsd,
            fuchsia,
            ios,
            kfreebsd,
            linux,
            lv2,
            macosx,
            netbsd,
            openbsd,
            solaris,
            windows,
            haiku,
            minix,
            rtems,
            nacl,
            cnk,
            aix,
            cuda,
            nvcl,
            amdhsa,
            ps4,
            elfiamcu,
            tvos,
            watchos,
            mesa3d,
            contiki,
            amdpal,
            hermit,
            hurd,
            wasi,
            emscripten,
            uefi,
            other,

            pub fn isDarwin(tag: Tag) bool {
                return switch (tag) {
                    .ios, .macosx, .watchos, .tvos => true,
                    else => false,
                };
            }

            pub fn dynamicLibSuffix(tag: Tag) [:0]const u8 {
                if (tag.isDarwin()) {
                    return ".dylib";
                }
                switch (tag) {
                    .windows => return ".dll",
                    else => return ".so",
                }
            }
        };

        /// Based on NTDDI version constants from
        /// https://docs.microsoft.com/en-us/cpp/porting/modifying-winver-and-win32-winnt
        pub const WindowsVersion = enum(u32) {
            nt4 = 0x04000000,
            win2k = 0x05000000,
            xp = 0x05010000,
            ws2003 = 0x05020000,
            vista = 0x06000000,
            win7 = 0x06010000,
            win8 = 0x06020000,
            win8_1 = 0x06030000,
            win10 = 0x0A000000,
            win10_th2 = 0x0A000001,
            win10_rs1 = 0x0A000002,
            win10_rs2 = 0x0A000003,
            win10_rs3 = 0x0A000004,
            win10_rs4 = 0x0A000005,
            win10_rs5 = 0x0A000006,
            win10_19h1 = 0x0A000007,

            pub const Range = struct {
                min: WindowsVersion,
                max: WindowsVersion,

                pub fn includesVersion(self: Range, ver: WindowsVersion) bool {
                    return @enumToInt(ver) >= @enumToInt(self.min) and @enumToInt(ver) <= @enumToInt(self.max);
                }
            };
        };

        pub const LinuxVersionRange = struct {
            range: Version.Range,
            glibc: Version,

            pub fn includesVersion(self: LinuxVersionRange, ver: Version) bool {
                return self.range.includesVersion(ver);
            }
        };

        /// The version ranges here represent the minimum OS version to be supported
        /// and the maximum OS version to be supported. The default values represent
        /// the range that the Zig Standard Library bases its abstractions on.
        ///
        /// The minimum version of the range is the main setting to tweak for a target.
        /// Usually, the maximum target OS version will remain the default, which is
        /// the latest released version of the OS.
        ///
        /// To test at compile time if the target is guaranteed to support a given OS feature,
        /// one should check that the minimum version of the range is greater than or equal to
        /// the version the feature was introduced in.
        ///
        /// To test at compile time if the target certainly will not support a given OS feature,
        /// one should check that the maximum version of the range is less than the version the
        /// feature was introduced in.
        ///
        /// If neither of these cases apply, a runtime check should be used to determine if the
        /// target supports a given OS feature.
        ///
        /// Binaries built with a given maximum version will continue to function on newer operating system
        /// versions. However, such a binary may not take full advantage of the newer operating system APIs.
        pub const VersionRange = union {
            none: void,
            semver: Version.Range,
            linux: LinuxVersionRange,
            windows: WindowsVersion.Range,

            /// The default `VersionRange` represents the range that the Zig Standard Library
            /// bases its abstractions on.
            pub fn default(tag: Tag) VersionRange {
                switch (tag) {
                    .freestanding,
                    .ananas,
                    .cloudabi,
                    .dragonfly,
                    .fuchsia,
                    .ios,
                    .kfreebsd,
                    .lv2,
                    .solaris,
                    .haiku,
                    .minix,
                    .rtems,
                    .nacl,
                    .cnk,
                    .aix,
                    .cuda,
                    .nvcl,
                    .amdhsa,
                    .ps4,
                    .elfiamcu,
                    .tvos,
                    .watchos,
                    .mesa3d,
                    .contiki,
                    .amdpal,
                    .hermit,
                    .hurd,
                    .wasi,
                    .emscripten,
                    .uefi,
                    .other,
                    => return .{ .none = {} },

                    .freebsd => return .{
                        .semver = Version.Range{
                            .min = .{ .major = 12, .minor = 0 },
                            .max = .{ .major = 12, .minor = 1 },
                        },
                    },
                    .macosx => return .{
                        .semver = .{
                            .min = .{ .major = 10, .minor = 13 },
                            .max = .{ .major = 10, .minor = 15, .patch = 3 },
                        },
                    },
                    .netbsd => return .{
                        .semver = .{
                            .min = .{ .major = 8, .minor = 0 },
                            .max = .{ .major = 9, .minor = 0 },
                        },
                    },
                    .openbsd => return .{
                        .semver = .{
                            .min = .{ .major = 6, .minor = 6 },
                            .max = .{ .major = 6, .minor = 6 },
                        },
                    },

                    .linux => return .{
                        .linux = .{
                            .range = .{
                                .min = .{ .major = 3, .minor = 16 },
                                .max = .{ .major = 5, .minor = 5, .patch = 5 },
                            },
                            .glibc = .{ .major = 2, .minor = 17 },
                        },
                    },

                    .windows => return .{
                        .windows = .{
                            .min = .win8_1,
                            .max = .win10_19h1,
                        },
                    },
                }
            }
        };

        pub fn defaultVersionRange(tag: Tag) Os {
            return .{
                .tag = tag,
                .version_range = VersionRange.default(tag),
            };
        }

        pub fn requiresLibC(os: Os) bool {
            return switch (os.tag) {
                .freebsd,
                .netbsd,
                .macosx,
                .ios,
                .tvos,
                .watchos,
                .dragonfly,
                .openbsd,
                => true,

                .linux,
                .windows,
                .freestanding,
                .ananas,
                .cloudabi,
                .fuchsia,
                .kfreebsd,
                .lv2,
                .solaris,
                .haiku,
                .minix,
                .rtems,
                .nacl,
                .cnk,
                .aix,
                .cuda,
                .nvcl,
                .amdhsa,
                .ps4,
                .elfiamcu,
                .mesa3d,
                .contiki,
                .amdpal,
                .hermit,
                .hurd,
                .wasi,
                .emscripten,
                .uefi,
                .other,
                => false,
            };
        }
    };

    pub const aarch64 = @import("target/aarch64.zig");
    pub const amdgpu = @import("target/amdgpu.zig");
    pub const arm = @import("target/arm.zig");
    pub const avr = @import("target/avr.zig");
    pub const bpf = @import("target/bpf.zig");
    pub const hexagon = @import("target/hexagon.zig");
    pub const mips = @import("target/mips.zig");
    pub const msp430 = @import("target/msp430.zig");
    pub const nvptx = @import("target/nvptx.zig");
    pub const powerpc = @import("target/powerpc.zig");
    pub const riscv = @import("target/riscv.zig");
    pub const sparc = @import("target/sparc.zig");
    pub const systemz = @import("target/systemz.zig");
    pub const wasm = @import("target/wasm.zig");
    pub const x86 = @import("target/x86.zig");

    pub const Abi = enum {
        none,
        gnu,
        gnuabin32,
        gnuabi64,
        gnueabi,
        gnueabihf,
        gnux32,
        code16,
        eabi,
        eabihf,
        elfv1,
        elfv2,
        android,
        musl,
        musleabi,
        musleabihf,
        msvc,
        itanium,
        cygnus,
        coreclr,
        simulator,
        macabi,

        pub fn default(arch: Cpu.Arch, target_os: Os) Abi {
            if (arch.isWasm()) {
                return .musl;
            }
            switch (target_os.tag) {
                .freestanding,
                .ananas,
                .cloudabi,
                .dragonfly,
                .lv2,
                .solaris,
                .haiku,
                .minix,
                .rtems,
                .nacl,
                .cnk,
                .aix,
                .cuda,
                .nvcl,
                .amdhsa,
                .ps4,
                .elfiamcu,
                .mesa3d,
                .contiki,
                .amdpal,
                .hermit,
                .other,
                => return .eabi,
                .openbsd,
                .macosx,
                .freebsd,
                .ios,
                .tvos,
                .watchos,
                .fuchsia,
                .kfreebsd,
                .netbsd,
                .hurd,
                => return .gnu,
                .windows,
                .uefi,
                => return .msvc,
                .linux,
                .wasi,
                .emscripten,
                => return .musl,
            }
        }

        pub fn isGnu(abi: Abi) bool {
            return switch (abi) {
                .gnu, .gnuabin32, .gnuabi64, .gnueabi, .gnueabihf, .gnux32 => true,
                else => false,
            };
        }

        pub fn isMusl(abi: Abi) bool {
            return switch (abi) {
                .musl, .musleabi, .musleabihf => true,
                else => false,
            };
        }

        pub fn oFileExt(abi: Abi) [:0]const u8 {
            return switch (abi) {
                .msvc => ".obj",
                else => ".o",
            };
        }
    };

    pub const ObjectFormat = enum {
        unknown,
        coff,
        elf,
        macho,
        wasm,
    };

    pub const SubSystem = enum {
        Console,
        Windows,
        Posix,
        Native,
        EfiApplication,
        EfiBootServiceDriver,
        EfiRom,
        EfiRuntimeDriver,
    };

    pub const Cpu = struct {
        /// Architecture
        arch: Arch,

        /// The CPU model to target. It has a set of features
        /// which are overridden with the `features` field.
        model: *const Model,

        /// An explicit list of the entire CPU feature set. It may differ from the specific CPU model's features.
        features: Feature.Set,

        pub const Feature = struct {
            /// The bit index into `Set`. Has a default value of `undefined` because the canonical
            /// structures are populated via comptime logic.
            index: Set.Index = undefined,

            /// Has a default value of `undefined` because the canonical
            /// structures are populated via comptime logic.
            name: []const u8 = undefined,

            /// If this corresponds to an LLVM-recognized feature, this will be populated;
            /// otherwise null.
            llvm_name: ?[:0]const u8,

            /// Human-friendly UTF-8 text.
            description: []const u8,

            /// Sparse `Set` of features this depends on.
            dependencies: Set,

            /// A bit set of all the features.
            pub const Set = struct {
                ints: [usize_count]usize,

                pub const needed_bit_count = 154;
                pub const byte_count = (needed_bit_count + 7) / 8;
                pub const usize_count = (byte_count + (@sizeOf(usize) - 1)) / @sizeOf(usize);
                pub const Index = std.math.Log2Int(std.meta.IntType(false, usize_count * @bitSizeOf(usize)));
                pub const ShiftInt = std.math.Log2Int(usize);

                pub const empty = Set{ .ints = [1]usize{0} ** usize_count };
                pub fn empty_workaround() Set {
                    return Set{ .ints = [1]usize{0} ** usize_count };
                }

                pub fn isEmpty(set: Set) bool {
                    return for (set.ints) |x| {
                        if (x != 0) break false;
                    } else true;
                }

                pub fn isEnabled(set: Set, arch_feature_index: Index) bool {
                    const usize_index = arch_feature_index / @bitSizeOf(usize);
                    const bit_index = @intCast(ShiftInt, arch_feature_index % @bitSizeOf(usize));
                    return (set.ints[usize_index] & (@as(usize, 1) << bit_index)) != 0;
                }

                /// Adds the specified feature but not its dependencies.
                pub fn addFeature(set: *Set, arch_feature_index: Index) void {
                    const usize_index = arch_feature_index / @bitSizeOf(usize);
                    const bit_index = @intCast(ShiftInt, arch_feature_index % @bitSizeOf(usize));
                    set.ints[usize_index] |= @as(usize, 1) << bit_index;
                }

                /// Adds the specified feature set but not its dependencies.
                pub fn addFeatureSet(set: *Set, other_set: Set) void {
                    set.ints = @as(@Vector(usize_count, usize), set.ints) |
                        @as(@Vector(usize_count, usize), other_set.ints);
                }

                /// Removes the specified feature but not its dependents.
                pub fn removeFeature(set: *Set, arch_feature_index: Index) void {
                    const usize_index = arch_feature_index / @bitSizeOf(usize);
                    const bit_index = @intCast(ShiftInt, arch_feature_index % @bitSizeOf(usize));
                    set.ints[usize_index] &= ~(@as(usize, 1) << bit_index);
                }

                /// Removes the specified feature but not its dependents.
                pub fn removeFeatureSet(set: *Set, other_set: Set) void {
                    // TODO should be able to use binary not on @Vector type.
                    // https://github.com/ziglang/zig/issues/903
                    for (set.ints) |*int, i| {
                        int.* &= ~other_set.ints[i];
                    }
                }

                pub fn populateDependencies(set: *Set, all_features_list: []const Cpu.Feature) void {
                    @setEvalBranchQuota(1000000);

                    var old = set.ints;
                    while (true) {
                        for (all_features_list) |feature, index_usize| {
                            const index = @intCast(Index, index_usize);
                            if (set.isEnabled(index)) {
                                set.addFeatureSet(feature.dependencies);
                            }
                        }
                        const nothing_changed = mem.eql(usize, &old, &set.ints);
                        if (nothing_changed) return;
                        old = set.ints;
                    }
                }

                pub fn asBytes(set: *const Set) *const [byte_count]u8 {
                    return @ptrCast(*const [byte_count]u8, &set.ints);
                }

                pub fn eql(set: Set, other: Set) bool {
                    return mem.eql(usize, &set.ints, &other.ints);
                }
            };

            pub fn feature_set_fns(comptime F: type) type {
                return struct {
                    /// Populates only the feature bits specified.
                    pub fn featureSet(features: []const F) Set {
                        var x = Set.empty_workaround(); // TODO remove empty_workaround
                        for (features) |feature| {
                            x.addFeature(@enumToInt(feature));
                        }
                        return x;
                    }

                    pub fn featureSetHas(set: Set, feature: F) bool {
                        return set.isEnabled(@enumToInt(feature));
                    }
                };
            }
        };

        pub const Arch = enum {
            arm,
            armeb,
            aarch64,
            aarch64_be,
            aarch64_32,
            arc,
            avr,
            bpfel,
            bpfeb,
            hexagon,
            mips,
            mipsel,
            mips64,
            mips64el,
            msp430,
            powerpc,
            powerpc64,
            powerpc64le,
            r600,
            amdgcn,
            riscv32,
            riscv64,
            sparc,
            sparcv9,
            sparcel,
            s390x,
            tce,
            tcele,
            thumb,
            thumbeb,
            i386,
            x86_64,
            xcore,
            nvptx,
            nvptx64,
            le32,
            le64,
            amdil,
            amdil64,
            hsail,
            hsail64,
            spir,
            spir64,
            kalimba,
            shave,
            lanai,
            wasm32,
            wasm64,
            renderscript32,
            renderscript64,

            pub fn isARM(arch: Arch) bool {
                return switch (arch) {
                    .arm, .armeb => true,
                    else => false,
                };
            }

            pub fn isThumb(arch: Arch) bool {
                return switch (arch) {
                    .thumb, .thumbeb => true,
                    else => false,
                };
            }

            pub fn isWasm(arch: Arch) bool {
                return switch (arch) {
                    .wasm32, .wasm64 => true,
                    else => false,
                };
            }

            pub fn isRISCV(arch: Arch) bool {
                return switch (arch) {
                    .riscv32, .riscv64 => true,
                    else => false,
                };
            }

            pub fn isMIPS(arch: Arch) bool {
                return switch (arch) {
                    .mips, .mipsel, .mips64, .mips64el => true,
                    else => false,
                };
            }

            pub fn parseCpuModel(arch: Arch, cpu_name: []const u8) !*const Cpu.Model {
                for (arch.allCpuModels()) |cpu| {
                    if (mem.eql(u8, cpu_name, cpu.name)) {
                        return cpu;
                    }
                }
                return error.UnknownCpuModel;
            }

            pub fn toElfMachine(arch: Arch) std.elf.EM {
                return switch (arch) {
                    .avr => ._AVR,
                    .msp430 => ._MSP430,
                    .arc => ._ARC,
                    .arm => ._ARM,
                    .armeb => ._ARM,
                    .hexagon => ._HEXAGON,
                    .le32 => ._NONE,
                    .mips => ._MIPS,
                    .mipsel => ._MIPS_RS3_LE,
                    .powerpc => ._PPC,
                    .r600 => ._NONE,
                    .riscv32 => ._RISCV,
                    .sparc => ._SPARC,
                    .sparcel => ._SPARC,
                    .tce => ._NONE,
                    .tcele => ._NONE,
                    .thumb => ._ARM,
                    .thumbeb => ._ARM,
                    .i386 => ._386,
                    .xcore => ._XCORE,
                    .nvptx => ._NONE,
                    .amdil => ._NONE,
                    .hsail => ._NONE,
                    .spir => ._NONE,
                    .kalimba => ._CSR_KALIMBA,
                    .shave => ._NONE,
                    .lanai => ._LANAI,
                    .wasm32 => ._NONE,
                    .renderscript32 => ._NONE,
                    .aarch64_32 => ._AARCH64,
                    .aarch64 => ._AARCH64,
                    .aarch64_be => ._AARCH64,
                    .mips64 => ._MIPS,
                    .mips64el => ._MIPS_RS3_LE,
                    .powerpc64 => ._PPC64,
                    .powerpc64le => ._PPC64,
                    .riscv64 => ._RISCV,
                    .x86_64 => ._X86_64,
                    .nvptx64 => ._NONE,
                    .le64 => ._NONE,
                    .amdil64 => ._NONE,
                    .hsail64 => ._NONE,
                    .spir64 => ._NONE,
                    .wasm64 => ._NONE,
                    .renderscript64 => ._NONE,
                    .amdgcn => ._NONE,
                    .bpfel => ._BPF,
                    .bpfeb => ._BPF,
                    .sparcv9 => ._SPARCV9,
                    .s390x => ._S390,
                };
            }

            pub fn endian(arch: Arch) builtin.Endian {
                return switch (arch) {
                    .avr,
                    .arm,
                    .aarch64_32,
                    .aarch64,
                    .amdgcn,
                    .amdil,
                    .amdil64,
                    .bpfel,
                    .hexagon,
                    .hsail,
                    .hsail64,
                    .kalimba,
                    .le32,
                    .le64,
                    .mipsel,
                    .mips64el,
                    .msp430,
                    .nvptx,
                    .nvptx64,
                    .sparcel,
                    .tcele,
                    .powerpc64le,
                    .r600,
                    .riscv32,
                    .riscv64,
                    .i386,
                    .x86_64,
                    .wasm32,
                    .wasm64,
                    .xcore,
                    .thumb,
                    .spir,
                    .spir64,
                    .renderscript32,
                    .renderscript64,
                    .shave,
                    => .Little,

                    .arc,
                    .armeb,
                    .aarch64_be,
                    .bpfeb,
                    .mips,
                    .mips64,
                    .powerpc,
                    .powerpc64,
                    .thumbeb,
                    .sparc,
                    .sparcv9,
                    .tce,
                    .lanai,
                    .s390x,
                    => .Big,
                };
            }

            pub fn ptrBitWidth(arch: Arch) u32 {
                switch (arch) {
                    .avr,
                    .msp430,
                    => return 16,

                    .arc,
                    .arm,
                    .armeb,
                    .hexagon,
                    .le32,
                    .mips,
                    .mipsel,
                    .powerpc,
                    .r600,
                    .riscv32,
                    .sparc,
                    .sparcel,
                    .tce,
                    .tcele,
                    .thumb,
                    .thumbeb,
                    .i386,
                    .xcore,
                    .nvptx,
                    .amdil,
                    .hsail,
                    .spir,
                    .kalimba,
                    .shave,
                    .lanai,
                    .wasm32,
                    .renderscript32,
                    .aarch64_32,
                    => return 32,

                    .aarch64,
                    .aarch64_be,
                    .mips64,
                    .mips64el,
                    .powerpc64,
                    .powerpc64le,
                    .riscv64,
                    .x86_64,
                    .nvptx64,
                    .le64,
                    .amdil64,
                    .hsail64,
                    .spir64,
                    .wasm64,
                    .renderscript64,
                    .amdgcn,
                    .bpfel,
                    .bpfeb,
                    .sparcv9,
                    .s390x,
                    => return 64,
                }
            }

            /// Returns a name that matches the lib/std/target/* directory name.
            pub fn genericName(arch: Arch) []const u8 {
                return switch (arch) {
                    .arm, .armeb, .thumb, .thumbeb => "arm",
                    .aarch64, .aarch64_be, .aarch64_32 => "aarch64",
                    .avr => "avr",
                    .bpfel, .bpfeb => "bpf",
                    .hexagon => "hexagon",
                    .mips, .mipsel, .mips64, .mips64el => "mips",
                    .msp430 => "msp430",
                    .powerpc, .powerpc64, .powerpc64le => "powerpc",
                    .amdgcn => "amdgpu",
                    .riscv32, .riscv64 => "riscv",
                    .sparc, .sparcv9, .sparcel => "sparc",
                    .s390x => "systemz",
                    .i386, .x86_64 => "x86",
                    .nvptx, .nvptx64 => "nvptx",
                    .wasm32, .wasm64 => "wasm",
                    else => @tagName(arch),
                };
            }

            /// All CPU features Zig is aware of, sorted lexicographically by name.
            pub fn allFeaturesList(arch: Arch) []const Cpu.Feature {
                return switch (arch) {
                    .arm, .armeb, .thumb, .thumbeb => &arm.all_features,
                    .aarch64, .aarch64_be, .aarch64_32 => &aarch64.all_features,
                    .avr => &avr.all_features,
                    .bpfel, .bpfeb => &bpf.all_features,
                    .hexagon => &hexagon.all_features,
                    .mips, .mipsel, .mips64, .mips64el => &mips.all_features,
                    .msp430 => &msp430.all_features,
                    .powerpc, .powerpc64, .powerpc64le => &powerpc.all_features,
                    .amdgcn => &amdgpu.all_features,
                    .riscv32, .riscv64 => &riscv.all_features,
                    .sparc, .sparcv9, .sparcel => &sparc.all_features,
                    .s390x => &systemz.all_features,
                    .i386, .x86_64 => &x86.all_features,
                    .nvptx, .nvptx64 => &nvptx.all_features,
                    .wasm32, .wasm64 => &wasm.all_features,

                    else => &[0]Cpu.Feature{},
                };
            }

            /// All processors Zig is aware of, sorted lexicographically by name.
            pub fn allCpuModels(arch: Arch) []const *const Cpu.Model {
                return switch (arch) {
                    .arm, .armeb, .thumb, .thumbeb => arm.all_cpus,
                    .aarch64, .aarch64_be, .aarch64_32 => aarch64.all_cpus,
                    .avr => avr.all_cpus,
                    .bpfel, .bpfeb => bpf.all_cpus,
                    .hexagon => hexagon.all_cpus,
                    .mips, .mipsel, .mips64, .mips64el => mips.all_cpus,
                    .msp430 => msp430.all_cpus,
                    .powerpc, .powerpc64, .powerpc64le => powerpc.all_cpus,
                    .amdgcn => amdgpu.all_cpus,
                    .riscv32, .riscv64 => riscv.all_cpus,
                    .sparc, .sparcv9, .sparcel => sparc.all_cpus,
                    .s390x => systemz.all_cpus,
                    .i386, .x86_64 => x86.all_cpus,
                    .nvptx, .nvptx64 => nvptx.all_cpus,
                    .wasm32, .wasm64 => wasm.all_cpus,

                    else => &[0]*const Model{},
                };
            }
        };

        pub const Model = struct {
            name: []const u8,
            llvm_name: ?[:0]const u8,
            features: Feature.Set,

            pub fn toCpu(model: *const Model, arch: Arch) Cpu {
                var features = model.features;
                features.populateDependencies(arch.allFeaturesList());
                return .{
                    .arch = arch,
                    .model = model,
                    .features = features,
                };
            }

            pub fn baseline(arch: Arch) *const Model {
                const S = struct {
                    const generic_model = Model{
                        .name = "generic",
                        .llvm_name = null,
                        .features = Cpu.Feature.Set.empty,
                    };
                };
                return switch (arch) {
                    .arm, .armeb, .thumb, .thumbeb => &arm.cpu.baseline,
                    .aarch64, .aarch64_be, .aarch64_32 => &aarch64.cpu.generic,
                    .avr => &avr.cpu.avr1,
                    .bpfel, .bpfeb => &bpf.cpu.generic,
                    .hexagon => &hexagon.cpu.generic,
                    .mips, .mipsel => &mips.cpu.mips32,
                    .mips64, .mips64el => &mips.cpu.mips64,
                    .msp430 => &msp430.cpu.generic,
                    .powerpc, .powerpc64, .powerpc64le => &powerpc.cpu.generic,
                    .amdgcn => &amdgpu.cpu.generic,
                    .riscv32 => &riscv.cpu.baseline_rv32,
                    .riscv64 => &riscv.cpu.baseline_rv64,
                    .sparc, .sparcv9, .sparcel => &sparc.cpu.generic,
                    .s390x => &systemz.cpu.generic,
                    .i386 => &x86.cpu.pentium4,
                    .x86_64 => &x86.cpu.x86_64,
                    .nvptx, .nvptx64 => &nvptx.cpu.sm_20,
                    .wasm32, .wasm64 => &wasm.cpu.generic,

                    else => &S.generic_model,
                };
            }
        };

        /// The "default" set of CPU features for cross-compiling. A conservative set
        /// of features that is expected to be supported on most available hardware.
        pub fn baseline(arch: Arch) Cpu {
            return Model.baseline(arch).toCpu(arch);
        }
    };

    pub const current = Target{
        .cpu = builtin.cpu,
        .os = builtin.os,
        .abi = builtin.abi,
    };

    pub const stack_align = 16;

    pub fn zigTriple(self: Target, allocator: *mem.Allocator) ![:0]u8 {
        return std.zig.CrossTarget.fromTarget(self).zigTriple(allocator);
    }

    pub fn linuxTripleSimple(allocator: *mem.Allocator, cpu_arch: Cpu.Arch, os_tag: Os.Tag, abi: Abi) ![:0]u8 {
        return std.fmt.allocPrint0(allocator, "{}-{}-{}", .{ @tagName(cpu_arch), @tagName(os_tag), @tagName(abi) });
    }

    pub fn linuxTriple(self: Target, allocator: *mem.Allocator) ![:0]u8 {
        return linuxTripleSimple(allocator, self.cpu.arch, self.os.tag, self.abi);
    }

    pub fn oFileExt(self: Target) [:0]const u8 {
        return self.abi.oFileExt();
    }

    pub fn exeFileExtSimple(cpu_arch: Cpu.Arch, os_tag: Os.Tag) [:0]const u8 {
        switch (os_tag) {
            .windows => return ".exe",
            .uefi => return ".efi",
            else => if (cpu_arch.isWasm()) {
                return ".wasm";
            } else {
                return "";
            },
        }
    }

    pub fn exeFileExt(self: Target) [:0]const u8 {
        return exeFileExtSimple(self.cpu.arch, self.os.tag);
    }

    pub fn staticLibSuffix_cpu_arch_abi(cpu_arch: Cpu.Arch, abi: Abi) [:0]const u8 {
        if (cpu_arch.isWasm()) {
            return ".wasm";
        }
        switch (abi) {
            .msvc => return ".lib",
            else => return ".a",
        }
    }

    pub fn staticLibSuffix(self: Target) [:0]const u8 {
        return staticLibSuffix_cpu_arch_abi(self.cpu.arch, self.abi);
    }

    pub fn dynamicLibSuffix(self: Target) [:0]const u8 {
        return self.os.tag.dynamicLibSuffix();
    }

    pub fn libPrefix_cpu_arch_abi(cpu_arch: Cpu.Arch, abi: Abi) [:0]const u8 {
        if (cpu_arch.isWasm()) {
            return "";
        }
        switch (abi) {
            .msvc => return "",
            else => return "lib",
        }
    }

    pub fn libPrefix(self: Target) [:0]const u8 {
        return libPrefix_cpu_arch_abi(self.cpu.arch, self.abi);
    }

    pub fn getObjectFormat(self: Target) ObjectFormat {
        if (self.os.tag == .windows or self.os.tag == .uefi) {
            return .coff;
        } else if (self.isDarwin()) {
            return .macho;
        }
        if (self.cpu.arch.isWasm()) {
            return .wasm;
        }
        return .elf;
    }

    pub fn isMinGW(self: Target) bool {
        return self.os.tag == .windows and self.isGnu();
    }

    pub fn isGnu(self: Target) bool {
        return self.abi.isGnu();
    }

    pub fn isMusl(self: Target) bool {
        return self.abi.isMusl();
    }

    pub fn isAndroid(self: Target) bool {
        return switch (self.abi) {
            .android => true,
            else => false,
        };
    }

    pub fn isWasm(self: Target) bool {
        return self.cpu.arch.isWasm();
    }

    pub fn isDarwin(self: Target) bool {
        return self.os.tag.isDarwin();
    }

    pub fn isGnuLibC_os_tag_abi(os_tag: Os.Tag, abi: Abi) bool {
        return os_tag == .linux and abi.isGnu();
    }

    pub fn isGnuLibC(self: Target) bool {
        return isGnuLibC_os_tag_abi(self.os.tag, self.abi);
    }

    pub fn supportsNewStackCall(self: Target) bool {
        return !self.cpu.arch.isWasm();
    }

    pub const FloatAbi = enum {
        hard,
        soft,
        soft_fp,
    };

    pub fn getFloatAbi(self: Target) FloatAbi {
        return switch (self.abi) {
            .gnueabihf,
            .eabihf,
            .musleabihf,
            => .hard,
            else => .soft,
        };
    }

    pub fn hasDynamicLinker(self: Target) bool {
        if (self.cpu.arch.isWasm()) {
            return false;
        }
        switch (self.os.tag) {
            .freestanding,
            .ios,
            .tvos,
            .watchos,
            .macosx,
            .uefi,
            .windows,
            .emscripten,
            .other,
            => return false,
            else => return true,
        }
    }

    /// Caller owns returned memory.
    pub fn getStandardDynamicLinkerPath(
        self: Target,
        allocator: *mem.Allocator,
    ) error{
        OutOfMemory,
        UnknownDynamicLinkerPath,
        TargetHasNoDynamicLinker,
    }![:0]u8 {
        const a = allocator;
        if (self.isAndroid()) {
            return mem.dupeZ(a, u8, if (self.cpu.arch.ptrBitWidth() == 64)
                "/system/bin/linker64"
            else
                "/system/bin/linker");
        }

        if (self.isMusl()) {
            var result = try std.Buffer.init(allocator, "/lib/ld-musl-");
            defer result.deinit();

            var is_arm = false;
            switch (self.cpu.arch) {
                .arm, .thumb => {
                    try result.append("arm");
                    is_arm = true;
                },
                .armeb, .thumbeb => {
                    try result.append("armeb");
                    is_arm = true;
                },
                else => |arch| try result.append(@tagName(arch)),
            }
            if (is_arm and self.getFloatAbi() == .hard) {
                try result.append("hf");
            }
            try result.append(".so.1");
            return result.toOwnedSlice();
        }

        switch (self.os.tag) {
            .freebsd => return mem.dupeZ(a, u8, "/libexec/ld-elf.so.1"),
            .netbsd => return mem.dupeZ(a, u8, "/libexec/ld.elf_so"),
            .dragonfly => return mem.dupeZ(a, u8, "/libexec/ld-elf.so.2"),
            .linux => switch (self.cpu.arch) {
                .i386,
                .sparc,
                .sparcel,
                => return mem.dupeZ(a, u8, "/lib/ld-linux.so.2"),

                .aarch64 => return mem.dupeZ(a, u8, "/lib/ld-linux-aarch64.so.1"),
                .aarch64_be => return mem.dupeZ(a, u8, "/lib/ld-linux-aarch64_be.so.1"),
                .aarch64_32 => return mem.dupeZ(a, u8, "/lib/ld-linux-aarch64_32.so.1"),

                .arm,
                .armeb,
                .thumb,
                .thumbeb,
                => return mem.dupeZ(a, u8, switch (self.getFloatAbi()) {
                    .hard => "/lib/ld-linux-armhf.so.3",
                    else => "/lib/ld-linux.so.3",
                }),

                .mips,
                .mipsel,
                .mips64,
                .mips64el,
                => return error.UnknownDynamicLinkerPath,

                .powerpc => return mem.dupeZ(a, u8, "/lib/ld.so.1"),
                .powerpc64, .powerpc64le => return mem.dupeZ(a, u8, "/lib64/ld64.so.2"),
                .s390x => return mem.dupeZ(a, u8, "/lib64/ld64.so.1"),
                .sparcv9 => return mem.dupeZ(a, u8, "/lib64/ld-linux.so.2"),
                .x86_64 => return mem.dupeZ(a, u8, switch (self.abi) {
                    .gnux32 => "/libx32/ld-linux-x32.so.2",
                    else => "/lib64/ld-linux-x86-64.so.2",
                }),

                .riscv32 => return mem.dupeZ(a, u8, "/lib/ld-linux-riscv32-ilp32.so.1"),
                .riscv64 => return mem.dupeZ(a, u8, "/lib/ld-linux-riscv64-lp64.so.1"),

                .wasm32,
                .wasm64,
                => return error.TargetHasNoDynamicLinker,

                .arc,
                .avr,
                .bpfel,
                .bpfeb,
                .hexagon,
                .msp430,
                .r600,
                .amdgcn,
                .tce,
                .tcele,
                .xcore,
                .nvptx,
                .nvptx64,
                .le32,
                .le64,
                .amdil,
                .amdil64,
                .hsail,
                .hsail64,
                .spir,
                .spir64,
                .kalimba,
                .shave,
                .lanai,
                .renderscript32,
                .renderscript64,
                => return error.UnknownDynamicLinkerPath,
            },

            .freestanding,
            .ios,
            .tvos,
            .watchos,
            .macosx,
            .uefi,
            .windows,
            .emscripten,
            .other,
            => return error.TargetHasNoDynamicLinker,

            else => return error.UnknownDynamicLinkerPath,
        }
    }
};