WIP: hello world

std/os.zig

@@ -23,6 +23,7 @@ test "std.os" {
     _ = @import("os/time.zig");
     _ = @import("os/windows.zig");
     _ = @import("os/uefi.zig");
+    _ = @import("os/wasi.zig");
     _ = @import("os/get_app_data_dir.zig");
 }
 
@@ -33,6 +34,7 @@ pub const freebsd = @import("os/freebsd.zig");
 pub const netbsd = @import("os/netbsd.zig");
 pub const zen = @import("os/zen.zig");
 pub const uefi = @import("os/uefi.zig");
+pub const wasi = @import("os/wasi.zig");
 
 pub const posix = switch (builtin.os) {
     Os.linux => linux,
@@ -40,6 +42,7 @@ pub const posix = switch (builtin.os) {
     Os.freebsd => freebsd,
     Os.netbsd => netbsd,
     Os.zen => zen,
+    Os.wasi => wasi,
     else => @compileError("Unsupported OS"),
 };
 
@@ -187,7 +190,7 @@ pub fn abort() noreturn {
         c.abort();
     }
     switch (builtin.os) {
-        Os.linux, Os.macosx, Os.ios, Os.freebsd, Os.netbsd => {
+        Os.linux, Os.macosx, Os.ios, Os.freebsd, Os.netbsd, Os.wasi => {
             _ = posix.raise(posix.SIGABRT);
             _ = posix.raise(posix.SIGKILL);
             while (true) {}

std/os/wasi.zig

@@ -0,0 +1,105 @@
+use @import("wasi/core.zig");
+
+pub const STDIN_FILENO = 0;
+pub const STDOUT_FILENO = 1;
+pub const STDERR_FILENO = 2;
+
+pub const ESUCCESS = 0;
+pub const E2BIG = 1;
+pub const EACCES = 2;
+pub const EADDRINUSE = 3;
+pub const EADDRNOTAVAIL = 4;
+pub const EAFNOSUPPORT = 5;
+pub const EAGAIN = 6;
+pub const EALREADY = 7;
+pub const EBADF = 8;
+pub const EBADMSG = 9;
+pub const EBUSY = 10;
+pub const ECANCELED = 11;
+pub const ECHILD = 12;
+pub const ECONNABORTED = 13;
+pub const ECONNREFUSED = 14;
+pub const ECONNRESET = 15;
+pub const EDEADLK = 16;
+pub const EDESTADDRREQ = 17;
+pub const EDOM = 18;
+pub const EDQUOT = 19;
+pub const EEXIST = 20;
+pub const EFAULT = 21;
+pub const EFBIG = 22;
+pub const EHOSTUNREACH = 23;
+pub const EIDRM = 24;
+pub const EILSEQ = 25;
+pub const EINPROGRESS = 26;
+pub const EINTR = 27;
+pub const EINVAL = 28;
+pub const EIO = 29;
+pub const EISCONN = 30;
+pub const EISDIR = 31;
+pub const ELOOP = 32;
+pub const EMFILE = 33;
+pub const EMLINK = 34;
+pub const EMSGSIZE = 35;
+pub const EMULTIHOP = 36;
+pub const ENAMETOOLONG = 37;
+pub const ENETDOWN = 38;
+pub const ENETRESET = 39;
+pub const ENETUNREACH = 40;
+pub const ENFILE = 41;
+pub const ENOBUFS = 42;
+pub const ENODEV = 43;
+pub const ENOENT = 44;
+pub const ENOEXEC = 45;
+pub const ENOLCK = 46;
+pub const ENOLINK = 47;
+pub const ENOMEM = 48;
+pub const ENOMSG = 49;
+pub const ENOPROTOOPT = 50;
+pub const ENOSPC = 51;
+pub const ENOSYS = 52;
+pub const ENOTCONN = 53;
+pub const ENOTDIR = 54;
+pub const ENOTEMPTY = 55;
+pub const ENOTRECOVERABLE = 56;
+pub const ENOTSOCK = 57;
+pub const ENOTSUP = 58;
+pub const ENOTTY = 59;
+pub const ENXIO = 60;
+pub const EOVERFLOW = 61;
+pub const EOWNERDEAD = 62;
+pub const EPERM = 63;
+pub const EPIPE = 64;
+pub const EPROTO = 65;
+pub const EPROTONOSUPPORT = 66;
+pub const EPROTOTYPE = 67;
+pub const ERANGE = 68;
+pub const EROFS = 69;
+pub const ESPIPE = 70;
+pub const ESRCH = 71;
+pub const ESTALE = 72;
+pub const ETIMEDOUT = 73;
+pub const ETXTBSY = 74;
+pub const EXDEV = 75;
+pub const ENOTCAPABLE = 76;
+
+// TODO: figure out what's going on here
+pub fn getErrno(r: usize) usize {
+    const signed_r = @bitCast(isize, r);
+    return if (signed_r > -4096 and signed_r < 0) @intCast(usize, -signed_r) else 0;
+}
+
+pub fn exit(status: i32) noreturn {
+    __wasi_proc_exit(@bitCast(__wasi_exitcode_t, isize(status)));
+}
+
+pub fn write(fd: i32, buf: [*]const u8, count: usize) usize {
+    var nwritten: usize = undefined;
+
+    const iovs = []__wasi_ciovec_t{__wasi_ciovec_t{
+        .buf = buf,
+        .buf_len = count,
+    }};
+
+    _ = __wasi_fd_write(@bitCast(__wasi_fd_t, isize(fd)), &iovs[0], iovs.len, &nwritten);
+    return nwritten;
+}

std/os/wasi/core.zig

@@ -0,0 +1,12 @@
+pub const __wasi_errno_t = u16;
+pub const __wasi_exitcode_t = u32;
+pub const __wasi_fd_t = u32;
+
+pub const __wasi_ciovec_t = extern struct {
+    buf: [*]const u8,
+    buf_len: usize,
+};
+
+pub extern fn __wasi_proc_exit(rval: __wasi_exitcode_t) noreturn;
+
+pub extern fn __wasi_fd_write(fd: __wasi_fd_t, iovs: *const __wasi_ciovec_t, iovs_len: usize, nwritten: *usize) __wasi_errno_t;

std/special/bootstrap.zig

@@ -14,6 +14,8 @@ comptime {
         @export("main", main, strong_linkage);
     } else if (builtin.os == builtin.Os.windows) {
         @export("WinMainCRTStartup", WinMainCRTStartup, strong_linkage);
+    } else if (builtin.os == builtin.Os.wasi) {
+        @export("_start", wasiStart, strong_linkage);
     } else {
         @export("_start", _start, strong_linkage);
     }
@@ -43,6 +45,16 @@ nakedcc fn _start() noreturn {
     @noInlineCall(posixCallMainAndExit);
 }
 
+nakedcc fn wasiStart() noreturn {
+    // TODO: Decide if alloc at init is acceptable for args and env
+    // @llvm.wasm.mem.grow.i32
+    // __wasi_args_get()
+    // __wasi_args_sizes_get()
+    // __wasi_environ_get()
+    // __wasi_environ_sizes_get()
+    std.os.posix.exit(callMain());
+}
+
 extern fn WinMainCRTStartup() noreturn {
     @setAlignStack(16);
     if (!builtin.single_threaded) {

std/special/panic.zig

@@ -9,8 +9,9 @@ const std = @import("std");
 pub fn panic(msg: []const u8, error_return_trace: ?*builtin.StackTrace) noreturn {
     @setCold(true);
     switch (builtin.os) {
-        // TODO: fix panic in zen.
-        builtin.Os.freestanding, builtin.Os.zen => {
+        // TODO: fix panic in zen
+        // TODO: fix panic in wasi
+        builtin.Os.freestanding, builtin.Os.zen, builtin.Os.wasi => {
             while (true) {}
         },
         builtin.Os.uefi => {