From 075d300342afa72f5328c0ee4232151dd0968264 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carl=20=C3=85stholm?= Date: Fri, 5 Sep 2025 17:45:22 +0200 Subject: [PATCH 1/2] Remove `std.builtin.subsystem` The subsystem detection was flaky and often incorrect and was not actually needed by the compiler or standard library. The actual subsystem won't be known until at link time, so it doesn't make sense to try to determine it at compile time. --- lib/std/builtin.zig | 26 -------------------------- lib/std/start.zig | 21 +++++++++------------ 2 files changed, 9 insertions(+), 38 deletions(-) diff --git a/lib/std/builtin.zig b/lib/std/builtin.zig index a646e9ad80..7a0284220c 100644 --- a/lib/std/builtin.zig +++ b/lib/std/builtin.zig @@ -6,32 +6,6 @@ const root = @import("root"); pub const assembly = @import("builtin/assembly.zig"); -/// `explicit_subsystem` is missing when the subsystem is automatically detected, -/// so Zig standard library has the subsystem detection logic here. This should generally be -/// used rather than `explicit_subsystem`. -/// On non-Windows targets, this is `null`. -pub const subsystem: ?std.Target.SubSystem = blk: { - if (@hasDecl(builtin, "explicit_subsystem")) break :blk builtin.explicit_subsystem; - switch (builtin.os.tag) { - .windows => { - if (builtin.is_test) { - break :blk std.Target.SubSystem.Console; - } - if (@hasDecl(root, "main") or - @hasDecl(root, "WinMain") or - @hasDecl(root, "wWinMain") or - @hasDecl(root, "WinMainCRTStartup") or - @hasDecl(root, "wWinMainCRTStartup")) - { - break :blk std.Target.SubSystem.Windows; - } else { - break :blk std.Target.SubSystem.Console; - } - }, - else => break :blk null, - } -}; - /// This data structure is used by the Zig language code generation and /// therefore must be kept in sync with the compiler implementation. pub const StackTrace = struct { diff --git a/lib/std/start.zig b/lib/std/start.zig index 7f7cc2f083..c22a36f24f 100644 --- a/lib/std/start.zig +++ b/lib/std/start.zig @@ -734,24 +734,21 @@ pub fn call_wWinMain() std.os.windows.INT { // - u32 in PEB.ProcessParameters.dwShowWindow // Since STARTUPINFO is the bottleneck for the allowed values, we use `u16` as the // type which can coerce into i32/c_int/u32 depending on how the user defines their wWinMain - // (the Win32 docs show wWinMain with `int` as the type for nCmdShow). - const nCmdShow: u16 = nCmdShow: { - // This makes Zig match the nCmdShow behavior of a C program with a WinMain symbol: + // (the Win32 docs show wWinMain with `int` as the type for nShowCmd). + const nShowCmd: u16 = nShowCmd: { + // This makes Zig match the nShowCmd behavior of a C program with a WinMain symbol: // - With STARTF_USESHOWWINDOW set in STARTUPINFO.dwFlags of the CreateProcess call: - // - Compiled with subsystem:console -> nCmdShow is always SW_SHOWDEFAULT - // - Compiled with subsystem:windows -> nCmdShow is STARTUPINFO.wShowWindow from - // the parent CreateProcess call + // - nShowCmd is STARTUPINFO.wShowWindow from the parent CreateProcess call // - With STARTF_USESHOWWINDOW unset: - // - nCmdShow is always SW_SHOWDEFAULT + // - nShowCmd is always SW_SHOWDEFAULT const SW_SHOWDEFAULT = 10; const STARTF_USESHOWWINDOW = 1; - // root having a wWinMain means that std.builtin.subsystem will always have a non-null value. - if (std.builtin.subsystem.? == .Windows and peb.ProcessParameters.dwFlags & STARTF_USESHOWWINDOW != 0) { - break :nCmdShow @truncate(peb.ProcessParameters.dwShowWindow); + if (peb.ProcessParameters.dwFlags & STARTF_USESHOWWINDOW != 0) { + break :nShowCmd @truncate(peb.ProcessParameters.dwShowWindow); } - break :nCmdShow SW_SHOWDEFAULT; + break :nShowCmd SW_SHOWDEFAULT; }; // second parameter hPrevInstance, MSDN: "This parameter is always NULL" - return root.wWinMain(hInstance, null, lpCmdLine, nCmdShow); + return root.wWinMain(hInstance, null, lpCmdLine, nShowCmd); } From 54f2a7c833bf2ca0b370ebe2470bb0dd71206cba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carl=20=C3=85stholm?= Date: Fri, 5 Sep 2025 17:50:46 +0200 Subject: [PATCH 2/2] Move `std.Target.SubSystem` to `std.zig.Subsystem` Also updates the field names to conform with the rest of std. --- lib/std/Build/Step/Compile.zig | 13 +-- lib/std/Target.zig | 12 +-- lib/std/zig.zig | 28 +++++++ src/Compilation.zig | 2 +- src/link.zig | 2 +- src/link/Lld.zig | 81 +++++-------------- src/main.zig | 31 ++----- test/standalone/issue_5825/build.zig | 2 +- .../standalone/windows_entry_points/build.zig | 4 +- 9 files changed, 66 insertions(+), 109 deletions(-) diff --git a/lib/std/Build/Step/Compile.zig b/lib/std/Build/Step/Compile.zig index a5f2d696be..c82846a640 100644 --- a/lib/std/Build/Step/Compile.zig +++ b/lib/std/Build/Step/Compile.zig @@ -171,7 +171,7 @@ lto: ?std.zig.LtoMode = null, dll_export_fns: ?bool = null, -subsystem: ?std.Target.SubSystem = null, +subsystem: ?std.zig.Subsystem = null, /// (Windows) When targeting the MinGW ABI, use the unicode entry point (wmain/wWinMain) mingw_unicode_entry_point: bool = false, @@ -1764,16 +1764,7 @@ fn getZigArgs(compile: *Compile, fuzz: bool) ![][]const u8 { if (compile.subsystem) |subsystem| { try zig_args.append("--subsystem"); - try zig_args.append(switch (subsystem) { - .Console => "console", - .Windows => "windows", - .Posix => "posix", - .Native => "native", - .EfiApplication => "efi_application", - .EfiBootServiceDriver => "efi_boot_service_driver", - .EfiRom => "efi_rom", - .EfiRuntimeDriver => "efi_runtime_driver", - }); + try zig_args.append(@tagName(subsystem)); } if (compile.mingw_unicode_entry_point) { diff --git a/lib/std/Target.zig b/lib/std/Target.zig index cbbbc86398..a5af4c6511 100644 --- a/lib/std/Target.zig +++ b/lib/std/Target.zig @@ -1138,16 +1138,8 @@ pub fn toCoffMachine(target: *const Target) std.coff.IMAGE.FILE.MACHINE { }; } -pub const SubSystem = enum { - Console, - Windows, - Posix, - Native, - EfiApplication, - EfiBootServiceDriver, - EfiRom, - EfiRuntimeDriver, -}; +/// Deprecated; use 'std.zig.Subsystem' instead. To be removed after 0.16.0 is tagged. +pub const SubSystem = std.zig.Subsystem; pub const Cpu = struct { /// Architecture diff --git a/lib/std/zig.zig b/lib/std/zig.zig index dcdc727ae2..fa70ef7fc7 100644 --- a/lib/std/zig.zig +++ b/lib/std/zig.zig @@ -349,6 +349,34 @@ pub const BuildId = union(enum) { pub const LtoMode = enum { none, full, thin }; +pub const Subsystem = enum { + console, + windows, + posix, + native, + efi_application, + efi_boot_service_driver, + efi_rom, + efi_runtime_driver, + + /// Deprecated; use '.console' instead. To be removed after 0.16.0 is tagged. + pub const Console: Subsystem = .console; + /// Deprecated; use '.windows' instead. To be removed after 0.16.0 is tagged. + pub const Windows: Subsystem = .windows; + /// Deprecated; use '.posix' instead. To be removed after 0.16.0 is tagged. + pub const Posix: Subsystem = .posix; + /// Deprecated; use '.native' instead. To be removed after 0.16.0 is tagged. + pub const Native: Subsystem = .native; + /// Deprecated; use '.efi_application' instead. To be removed after 0.16.0 is tagged. + pub const EfiApplication: Subsystem = .efi_application; + /// Deprecated; use '.efi_boot_service_driver' instead. To be removed after 0.16.0 is tagged. + pub const EfiBootServiceDriver: Subsystem = .efi_boot_service_driver; + /// Deprecated; use '.efi_rom' instead. To be removed after 0.16.0 is tagged. + pub const EfiRom: Subsystem = .efi_rom; + /// Deprecated; use '.efi_runtime_driver' instead. To be removed after 0.16.0 is tagged. + pub const EfiRuntimeDriver: Subsystem = .efi_runtime_driver; +}; + /// Renders a `std.Target.Cpu` value into a textual representation that can be parsed /// via the `-mcpu` flag passed to the Zig compiler. /// Appends the result to `buffer`. diff --git a/src/Compilation.zig b/src/Compilation.zig index 9f0ab662a4..c6734aa3e7 100644 --- a/src/Compilation.zig +++ b/src/Compilation.zig @@ -1766,7 +1766,7 @@ pub const CreateOptions = struct { reference_trace: ?u32 = null, test_filters: []const []const u8 = &.{}, test_runner_path: ?[]const u8 = null, - subsystem: ?std.Target.SubSystem = null, + subsystem: ?std.zig.Subsystem = null, mingw_unicode_entry_point: bool = false, /// (Zig compiler development) Enable dumping linker's state as JSON. enable_link_snapshots: bool = false, diff --git a/src/link.zig b/src/link.zig index f324f23897..ce1d2a68f6 100644 --- a/src/link.zig +++ b/src/link.zig @@ -448,7 +448,7 @@ pub const File = struct { allow_shlib_undefined: ?bool, allow_undefined_version: bool, enable_new_dtags: ?bool, - subsystem: ?std.Target.SubSystem, + subsystem: ?std.zig.Subsystem, linker_script: ?[]const u8, version_script: ?[]const u8, soname: ?[]const u8, diff --git a/src/link/Lld.zig b/src/link/Lld.zig index 75aad965d9..d9c25f641d 100644 --- a/src/link/Lld.zig +++ b/src/link/Lld.zig @@ -19,7 +19,7 @@ const Coff = struct { minor_subsystem_version: u16, lib_directories: []const Cache.Directory, module_definition_file: ?[]const u8, - subsystem: ?std.Target.SubSystem, + subsystem: ?std.zig.Subsystem, /// These flags are populated by `codegen.llvm.updateExports` to allow us to guess the subsystem. lld_export_flags: struct { c_main: bool, @@ -554,7 +554,7 @@ fn coffLink(lld: *Lld, arena: Allocator) !void { try argv.append(try allocPrint(arena, "-DEF:{s}", .{def})); } - const resolved_subsystem: ?std.Target.SubSystem = blk: { + const resolved_subsystem: ?std.zig.Subsystem = blk: { if (coff.subsystem) |explicit| break :blk explicit; switch (target.os.tag) { .windows => { @@ -565,13 +565,13 @@ fn coffLink(lld: *Lld, arena: Allocator) !void { coff.lld_export_flags.winmain_crt_startup or coff.lld_export_flags.wwinmain_crt_startup) { - break :blk .Console; + break :blk .console; } if (coff.lld_export_flags.winmain or coff.lld_export_flags.wwinmain) - break :blk .Windows; + break :blk .windows; } }, - .uefi => break :blk .EfiApplication, + .uefi => break :blk .efi_application, else => {}, } break :blk null; @@ -580,60 +580,23 @@ fn coffLink(lld: *Lld, arena: Allocator) !void { const Mode = enum { uefi, win32 }; const mode: Mode = mode: { if (resolved_subsystem) |subsystem| { - const subsystem_suffix = try allocPrint(arena, ",{d}.{d}", .{ - coff.major_subsystem_version, coff.minor_subsystem_version, - }); - - switch (subsystem) { - .Console => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:console{s}", .{ - subsystem_suffix, - })); - break :mode .win32; - }, - .EfiApplication => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_application{s}", .{ - subsystem_suffix, - })); - break :mode .uefi; - }, - .EfiBootServiceDriver => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_boot_service_driver{s}", .{ - subsystem_suffix, - })); - break :mode .uefi; - }, - .EfiRom => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_rom{s}", .{ - subsystem_suffix, - })); - break :mode .uefi; - }, - .EfiRuntimeDriver => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:efi_runtime_driver{s}", .{ - subsystem_suffix, - })); - break :mode .uefi; - }, - .Native => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:native{s}", .{ - subsystem_suffix, - })); - break :mode .win32; - }, - .Posix => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:posix{s}", .{ - subsystem_suffix, - })); - break :mode .win32; - }, - .Windows => { - try argv.append(try allocPrint(arena, "-SUBSYSTEM:windows{s}", .{ - subsystem_suffix, - })); - break :mode .win32; - }, - } + try argv.append(try allocPrint(arena, "-SUBSYSTEM:{s},{d}.{d}", .{ + @tagName(subsystem), + coff.major_subsystem_version, + coff.minor_subsystem_version, + })); + break :mode switch (subsystem) { + .console, + .windows, + .posix, + .native, + => .win32, + .efi_application, + .efi_boot_service_driver, + .efi_rom, + .efi_runtime_driver, + => .uefi, + }; } else if (target.os.tag == .uefi) { break :mode .uefi; } else { diff --git a/src/main.zig b/src/main.zig index e6815bc424..ccb8935972 100644 --- a/src/main.zig +++ b/src/main.zig @@ -893,7 +893,7 @@ fn buildOutputType( var override_global_cache_dir: ?[]const u8 = try EnvVar.ZIG_GLOBAL_CACHE_DIR.get(arena); var override_lib_dir: ?[]const u8 = try EnvVar.ZIG_LIB_DIR.get(arena); var clang_preprocessor_mode: Compilation.ClangPreprocessorMode = .no; - var subsystem: ?std.Target.SubSystem = null; + var subsystem: ?std.zig.Subsystem = null; var major_subsystem_version: ?u16 = null; var minor_subsystem_version: ?u16 = null; var mingw_unicode_entry_point: bool = false; @@ -1135,7 +1135,7 @@ fn buildOutputType( } n_jobs = num; } else if (mem.eql(u8, arg, "--subsystem")) { - subsystem = try parseSubSystem(args_iter.nextOrFatal()); + subsystem = try parseSubsystem(args_iter.nextOrFatal()); } else if (mem.eql(u8, arg, "-O")) { mod_opts.optimize_mode = parseOptimizeMode(args_iter.nextOrFatal()); } else if (mem.cutPrefix(u8, arg, "-fentry=")) |rest| { @@ -2415,7 +2415,7 @@ fn buildOutputType( } else if (mem.eql(u8, arg, "-rpath") or mem.eql(u8, arg, "--rpath") or mem.eql(u8, arg, "-R")) { try create_module.rpath_list.append(arena, linker_args_it.nextOrFatal()); } else if (mem.eql(u8, arg, "--subsystem")) { - subsystem = try parseSubSystem(linker_args_it.nextOrFatal()); + subsystem = try parseSubsystem(linker_args_it.nextOrFatal()); } else if (mem.eql(u8, arg, "-I") or mem.eql(u8, arg, "--dynamic-linker") or mem.eql(u8, arg, "-dynamic-linker")) @@ -2743,7 +2743,7 @@ fn buildOutputType( try symbol_wrap_set.put(arena, next_arg, {}); } else if (mem.startsWith(u8, arg, "/subsystem:")) { var split_it = mem.splitBackwardsScalar(u8, arg, ':'); - subsystem = try parseSubSystem(split_it.first()); + subsystem = try parseSubsystem(split_it.first()); } else if (mem.startsWith(u8, arg, "/implib:")) { var split_it = mem.splitBackwardsScalar(u8, arg, ':'); emit_implib = .{ .yes = split_it.first() }; @@ -6657,26 +6657,10 @@ fn warnAboutForeignBinaries( } } -fn parseSubSystem(next_arg: []const u8) !std.Target.SubSystem { - if (mem.eql(u8, next_arg, "console")) { - return .Console; - } else if (mem.eql(u8, next_arg, "windows")) { - return .Windows; - } else if (mem.eql(u8, next_arg, "posix")) { - return .Posix; - } else if (mem.eql(u8, next_arg, "native")) { - return .Native; - } else if (mem.eql(u8, next_arg, "efi_application")) { - return .EfiApplication; - } else if (mem.eql(u8, next_arg, "efi_boot_service_driver")) { - return .EfiBootServiceDriver; - } else if (mem.eql(u8, next_arg, "efi_rom")) { - return .EfiRom; - } else if (mem.eql(u8, next_arg, "efi_runtime_driver")) { - return .EfiRuntimeDriver; - } else { +fn parseSubsystem(arg: []const u8) !std.zig.Subsystem { + return std.meta.stringToEnum(std.zig.Subsystem, arg) orelse fatal("invalid: --subsystem: '{s}'. Options are:\n{s}", .{ - next_arg, + arg, \\ console \\ windows \\ posix @@ -6687,7 +6671,6 @@ fn parseSubSystem(next_arg: []const u8) !std.Target.SubSystem { \\ efi_runtime_driver \\ }); - } } /// Model a header searchlist as a group. diff --git a/test/standalone/issue_5825/build.zig b/test/standalone/issue_5825/build.zig index 3b4bb33def..e102febe2d 100644 --- a/test/standalone/issue_5825/build.zig +++ b/test/standalone/issue_5825/build.zig @@ -31,7 +31,7 @@ pub fn build(b: *std.Build) void { .target = target, }), }); - exe.subsystem = .Console; + exe.subsystem = .console; exe.root_module.linkSystemLibrary("kernel32", .{}); exe.root_module.linkSystemLibrary("ntdll", .{}); exe.root_module.addObject(obj); diff --git a/test/standalone/windows_entry_points/build.zig b/test/standalone/windows_entry_points/build.zig index 1889b0c843..c77a48ecd8 100644 --- a/test/standalone/windows_entry_points/build.zig +++ b/test/standalone/windows_entry_points/build.zig @@ -53,7 +53,7 @@ pub fn build(b: *std.Build) void { .link_libc = true, }), }); - // Note: `exe.subsystem = .Windows;` is not necessary + // Note: `exe.subsystem = .windows;` is not necessary exe.root_module.addCSourceFile(.{ .file = b.path("winmain.c") }); _ = exe.getEmittedBin(); @@ -71,7 +71,7 @@ pub fn build(b: *std.Build) void { }), }); exe.mingw_unicode_entry_point = true; - // Note: `exe.subsystem = .Windows;` is not necessary + // Note: `exe.subsystem = .windows;` is not necessary exe.root_module.addCSourceFile(.{ .file = b.path("wwinmain.c") }); _ = exe.getEmittedBin();