Commit c400cb429a

Andrew Kelley <superjoe30@gmail.com>
2017-04-03 10:58:19
zig build system: add setLinkerScript and setTarget
* See #204 - zig build system * allow builtin types Os, Environ, Arch to be used at runtime. they have zero_bits=false and debug info now. * Eradicate use of `@alloca` in std for syscalls. See #225 * add `std.io.writeFile` * `std.debug.panic` adds a newline to format
1 parent a1363b5
src/all_types.hpp
@@ -944,6 +944,7 @@ struct TypeTableEntryEnum {
     AstNode *decl_node;
     ContainerLayout layout;
     uint32_t src_field_count;
+    // number of fields in the union. 0 if enum with no payload
     uint32_t gen_field_count;
     TypeEnumField *fields;
     bool is_invalid; // true if any fields are invalid
src/codegen.cpp
@@ -3802,6 +3802,35 @@ static const GlobalLinkageValue global_linkage_values[] = {
     {GlobalLinkageIdLinkOnce, "LinkOnce"},
 };
 
+static void init_enum_debug_info(CodeGen *g, TypeTableEntry *enum_type) {
+    uint32_t field_count = enum_type->data.enumeration.src_field_count;
+
+    TypeTableEntry *tag_type_entry = get_smallest_unsigned_int_type(g, field_count);
+    enum_type->data.enumeration.tag_type = tag_type_entry;
+
+    ZigLLVMDIEnumerator **di_enumerators = allocate<ZigLLVMDIEnumerator*>(field_count);
+    for (uint32_t i = 0; i < field_count; i += 1) {
+        TypeEnumField *field = &enum_type->data.enumeration.fields[i];
+        di_enumerators[i] = ZigLLVMCreateDebugEnumerator(g->dbuilder, buf_ptr(field->name), i);
+    }
+
+    // create debug type for tag
+    uint64_t tag_debug_size_in_bits = 8*LLVMStoreSizeOfType(g->target_data_ref, tag_type_entry->type_ref);
+    uint64_t tag_debug_align_in_bits = 8*LLVMABISizeOfType(g->target_data_ref, tag_type_entry->type_ref);
+    enum_type->di_type = ZigLLVMCreateDebugEnumerationType(g->dbuilder,
+            nullptr, buf_ptr(&enum_type->name),
+            nullptr, 0,
+            tag_debug_size_in_bits,
+            tag_debug_align_in_bits,
+            di_enumerators, field_count,
+            tag_type_entry->di_type, "");
+
+    enum_type->type_ref = tag_type_entry->type_ref;
+
+    enum_type->data.enumeration.complete = true;
+    enum_type->data.enumeration.zero_bits_known = true;
+}
+
 static void define_builtin_types(CodeGen *g) {
     {
         // if this type is anywhere in the AST, we should never hit codegen.
@@ -4022,7 +4051,6 @@ static void define_builtin_types(CodeGen *g) {
 
     {
         TypeTableEntry *entry = new_type_table_entry(TypeTableEntryIdEnum);
-        entry->zero_bits = true; // only allowed at compile time
         buf_init_from_str(&entry->name, "Os");
         uint32_t field_count = target_os_count();
         entry->data.enumeration.src_field_count = field_count;
@@ -4038,11 +4066,8 @@ static void define_builtin_types(CodeGen *g) {
                 g->target_os_index = i;
             }
         }
-        entry->data.enumeration.complete = true;
-        entry->data.enumeration.zero_bits_known = true;
 
-        TypeTableEntry *tag_type_entry = get_smallest_unsigned_int_type(g, field_count);
-        entry->data.enumeration.tag_type = tag_type_entry;
+        init_enum_debug_info(g, entry);
 
         g->builtin_types.entry_os_enum = entry;
         g->primitive_type_table.put(&entry->name, entry);
@@ -4050,7 +4075,6 @@ static void define_builtin_types(CodeGen *g) {
 
     {
         TypeTableEntry *entry = new_type_table_entry(TypeTableEntryIdEnum);
-        entry->zero_bits = true; // only allowed at compile time
         buf_init_from_str(&entry->name, "Arch");
         uint32_t field_count = target_arch_count();
         entry->data.enumeration.src_field_count = field_count;
@@ -4072,11 +4096,8 @@ static void define_builtin_types(CodeGen *g) {
                 g->target_arch_index = i;
             }
         }
-        entry->data.enumeration.complete = true;
-        entry->data.enumeration.zero_bits_known = true;
 
-        TypeTableEntry *tag_type_entry = get_smallest_unsigned_int_type(g, field_count);
-        entry->data.enumeration.tag_type = tag_type_entry;
+        init_enum_debug_info(g, entry);
 
         g->builtin_types.entry_arch_enum = entry;
         g->primitive_type_table.put(&entry->name, entry);
@@ -4084,7 +4105,6 @@ static void define_builtin_types(CodeGen *g) {
 
     {
         TypeTableEntry *entry = new_type_table_entry(TypeTableEntryIdEnum);
-        entry->zero_bits = true; // only allowed at compile time
         buf_init_from_str(&entry->name, "Environ");
         uint32_t field_count = target_environ_count();
         entry->data.enumeration.src_field_count = field_count;
@@ -4100,11 +4120,8 @@ static void define_builtin_types(CodeGen *g) {
                 g->target_environ_index = i;
             }
         }
-        entry->data.enumeration.complete = true;
-        entry->data.enumeration.zero_bits_known = true;
 
-        TypeTableEntry *tag_type_entry = get_smallest_unsigned_int_type(g, field_count);
-        entry->data.enumeration.tag_type = tag_type_entry;
+        init_enum_debug_info(g, entry);
 
         g->builtin_types.entry_environ_enum = entry;
         g->primitive_type_table.put(&entry->name, entry);
@@ -4112,7 +4129,6 @@ static void define_builtin_types(CodeGen *g) {
 
     {
         TypeTableEntry *entry = new_type_table_entry(TypeTableEntryIdEnum);
-        entry->zero_bits = true; // only allowed at compile time
         buf_init_from_str(&entry->name, "ObjectFormat");
         uint32_t field_count = target_oformat_count();
         entry->data.enumeration.src_field_count = field_count;
@@ -4128,11 +4144,8 @@ static void define_builtin_types(CodeGen *g) {
                 g->target_oformat_index = i;
             }
         }
-        entry->data.enumeration.complete = true;
-        entry->data.enumeration.zero_bits_known = true;
 
-        TypeTableEntry *tag_type_entry = get_smallest_unsigned_int_type(g, field_count);
-        entry->data.enumeration.tag_type = tag_type_entry;
+        init_enum_debug_info(g, entry);
 
         g->builtin_types.entry_oformat_enum = entry;
         g->primitive_type_table.put(&entry->name, entry);
std/os/darwin.zig
@@ -71,17 +71,10 @@ pub fn close(fd: i32) -> usize {
     arch.syscall1(arch.SYS_close, usize(fd))
 }
 
-pub fn open_c(path: &const u8, flags: usize, perm: usize) -> usize {
+pub fn open(path: &const u8, flags: usize, perm: usize) -> usize {
     arch.syscall3(arch.SYS_open, usize(path), flags, perm)
 }
 
-pub fn open(path: []const u8, flags: usize, perm: usize) -> usize {
-    const buf = @alloca(u8, path.len + 1);
-    @memcpy(&buf[0], &path[0], path.len);
-    buf[path.len] = 0;
-    return open_c(buf.ptr, flags, perm);
-}
-
 pub fn read(fd: i32, buf: &u8, count: usize) -> usize {
     arch.syscall3(arch.SYS_read, usize(fd), usize(buf), count)
 }
std/os/index.zig
@@ -8,6 +8,8 @@ pub const posix = switch(@compileVar("os")) {
     else => @compileError("Unsupported OS"),
 };
 
+pub const max_noalloc_path_len = 1024;
+
 const debug = @import("../debug.zig");
 const assert = debug.assert;
 
@@ -105,11 +107,12 @@ fn makePipe() -> %[2]i32 {
 }
 
 fn destroyPipe(pipe: &const [2]i32) {
-    closeNoIntr((*pipe)[0]);
-    closeNoIntr((*pipe)[1]);
+    posixClose((*pipe)[0]);
+    posixClose((*pipe)[1]);
 }
 
-fn closeNoIntr(fd: i32) {
+/// Calls POSIX close, and keeps trying if it gets interrupted.
+pub fn posixClose(fd: i32) {
     while (true) {
         const err = posix.getErrno(posix.close(fd));
         if (err == errno.EINTR) {
@@ -120,9 +123,56 @@ fn closeNoIntr(fd: i32) {
     }
 }
 
-fn openNoIntr(path: []const u8, flags: usize, perm: usize) -> %i32 {
+/// Calls POSIX write, and keeps trying if it gets interrupted.
+pub fn posixWrite(fd: i32, bytes: []const u8) -> %void {
+    while (true) {
+        const write_ret = posix.write(fd, bytes.ptr, bytes.len);
+        const write_err = posix.getErrno(write_ret);
+        if (write_err > 0) {
+            return switch (write_err) {
+                errno.EINTR  => continue,
+                errno.EINVAL => unreachable,
+                errno.EDQUOT => error.DiskQuota,
+                errno.EFBIG  => error.FileTooBig,
+                errno.EIO    => error.Io,
+                errno.ENOSPC => error.NoSpaceLeft,
+                errno.EPERM  => error.BadPerm,
+                errno.EPIPE  => error.PipeFail,
+                else         => error.Unexpected,
+            }
+        }
+        return;
+    }
+}
+
+
+/// ::path may need to be copied in memory to add a null terminating byte. In this case
+/// a fixed size buffer of size ::max_noalloc_path_len is an attempted solution. If the fixed
+/// size buffer is too small, and the provided allocator is null, ::error.NameTooLong is returned.
+/// otherwise if the fixed size buffer is too small, allocator is used to obtain the needed memory.
+/// Calls POSIX open, keeps trying if it gets interrupted, and translates
+/// the return value into zig errors.
+pub fn posixOpen(path: []const u8, flags: usize, perm: usize, allocator: ?&Allocator) -> %i32 {
+    var stack_buf: [max_noalloc_path_len]u8 = undefined;
+    var path0: []u8 = undefined;
+    var need_free = false;
+
+    if (path.len < stack_buf.len) {
+        path0 = stack_buf[0...path.len + 1];
+    } else if (const a ?= allocator) {
+        path0 = %return a.alloc(u8, path.len + 1);
+        need_free = true;
+    } else {
+        return error.NameTooLong;
+    }
+    defer if (need_free) {
+        (??allocator).free(path0);
+    };
+    mem.copy(u8, path0, path);
+    path0[path.len] = 0;
+
     while (true) {
-        const result = posix.open(path, flags, perm);
+        const result = posix.open(path0.ptr, flags, perm);
         const err = posix.getErrno(result);
         if (err > 0) {
             return switch (err) {
@@ -247,8 +297,8 @@ pub const ChildProcess = struct {
 
     pub fn wait(self: &ChildProcess) -> %Term {
         defer {
-            closeNoIntr(self.err_pipe[0]);
-            closeNoIntr(self.err_pipe[1]);
+            posixClose(self.err_pipe[0]);
+            posixClose(self.err_pipe[1]);
         };
 
         var status: i32 = undefined;
@@ -328,13 +378,13 @@ pub const ChildProcess = struct {
         const any_ignore = (stdin == StdIo.Ignore or stdout == StdIo.Ignore or stderr == StdIo.Ignore);
         // TODO issue #295
         //const dev_null_fd = if (any_ignore) {
-        //    %return openNoIntr("/dev/null", posix.O_RDWR, 0)
+        //    %return posixOpen("/dev/null", posix.O_RDWR, 0, null)
         //} else {
         //    undefined
         //};
         var dev_null_fd: i32 = undefined;
         if (any_ignore)
-            dev_null_fd = %return openNoIntr("/dev/null", posix.O_RDWR, 0);
+            dev_null_fd = %return posixOpen("/dev/null", posix.O_RDWR, 0, null);
 
         // This pipe is used to communicate errors between the time of fork
         // and execve from the child process to the parent process.
@@ -374,10 +424,10 @@ pub const ChildProcess = struct {
         }
 
         // we are the parent
-        if (stdin == StdIo.Pipe) { closeNoIntr(stdin_pipe[0]); }
-        if (stdout == StdIo.Pipe) { closeNoIntr(stdout_pipe[1]); }
-        if (stderr == StdIo.Pipe) { closeNoIntr(stderr_pipe[1]); }
-        if (any_ignore) { closeNoIntr(dev_null_fd); }
+        if (stdin == StdIo.Pipe) { posixClose(stdin_pipe[0]); }
+        if (stdout == StdIo.Pipe) { posixClose(stdout_pipe[1]); }
+        if (stderr == StdIo.Pipe) { posixClose(stderr_pipe[1]); }
+        if (any_ignore) { posixClose(dev_null_fd); }
 
         return ChildProcess {
             .pid = i32(pid),
@@ -412,7 +462,7 @@ pub const ChildProcess = struct {
     fn setUpChildIo(stdio: StdIo, pipe_fd: i32, std_fileno: i32, dev_null_fd: i32) -> %void {
         switch (stdio) {
             StdIo.Pipe => %return dup2NoIntr(pipe_fd, std_fileno),
-            StdIo.Close => closeNoIntr(std_fileno),
+            StdIo.Close => posixClose(std_fileno),
             StdIo.Inherit => {},
             StdIo.Ignore => %return dup2NoIntr(dev_null_fd, std_fileno),
         }
std/os/linux.zig
@@ -303,39 +303,18 @@ pub fn pwrite(fd: i32, buf: &const u8, count: usize, offset: usize) -> usize {
     arch.syscall4(arch.SYS_pwrite, usize(fd), usize(buf), count, offset)
 }
 
-pub fn open_c(path: &const u8, flags: usize, perm: usize) -> usize {
+pub fn open(path: &const u8, flags: usize, perm: usize) -> usize {
     arch.syscall3(arch.SYS_open, usize(path), flags, perm)
 }
 
-pub fn open(path: []const u8, flags: usize, perm: usize) -> usize {
-    const buf = @alloca(u8, path.len + 1);
-    @memcpy(&buf[0], &path[0], path.len);
-    buf[path.len] = 0;
-    return open_c(buf.ptr, flags, perm);
-}
-
-pub fn create_c(path: &const u8, perm: usize) -> usize {
+pub fn create(path: &const u8, perm: usize) -> usize {
     arch.syscall2(arch.SYS_creat, usize(path), perm)
 }
 
-pub fn create(path: []const u8, perm: usize) -> usize {
-    const buf = @alloca(u8, path.len + 1);
-    @memcpy(&buf[0], &path[0], path.len);
-    buf[path.len] = 0;
-    return create_c(buf.ptr, perm);
-}
-
-pub fn openat_c(dirfd: i32, path: &const u8, flags: usize, mode: usize) -> usize {
+pub fn openat(dirfd: i32, path: &const u8, flags: usize, mode: usize) -> usize {
     arch.syscall4(arch.SYS_openat, usize(dirfd), usize(path), flags, mode)
 }
 
-pub fn openat(dirfd: i32, path: []const u8, flags: usize, mode: usize) -> usize {
-    const buf = @alloca(u8, path.len + 1);
-    @memcpy(&buf[0], &path[0], path.len);
-    buf[path.len] = 0;
-    return openat_c(dirfd, buf.ptr, flags, mode);
-}
-
 pub fn close(fd: i32) -> usize {
     arch.syscall1(arch.SYS_close, usize(fd))
 }
std/special/bootstrap.zig
@@ -33,6 +33,7 @@ export nakedcc fn _start() -> noreturn {
 }
 
 fn callMain(envp: &?&u8) -> %void {
+    // TODO issue #225
     const args = @alloca([]u8, argc);
     for (args) |_, i| {
         const ptr = argv[i];
@@ -41,6 +42,7 @@ fn callMain(envp: &?&u8) -> %void {
 
     var env_count: usize = 0;
     while (envp[env_count] != null; env_count += 1) {}
+    // TODO issue #225
     const environ = @alloca(std.os.EnvPair, env_count);
     for (environ) |_, env_i| {
         const ptr = ??envp[env_i];
std/special/zigrt.zig
@@ -11,6 +11,6 @@ export coldcc fn __zig_panic(message_ptr: &const u8, message_len: usize) -> nore
     } else if (@compileVar("os") == Os.freestanding) {
         while (true) {}
     } else {
-        @import("std").debug.panic("{}\n", message_ptr[0...message_len]);
+        @import("std").debug.panic("{}", message_ptr[0...message_len]);
     }
 }
std/build.zig
@@ -32,6 +32,8 @@ pub const Builder = struct {
         *exe = Exe {
             .root_src = root_src,
             .name = name,
+            .target = Target.Native,
+            .linker_script = LinkerScript.None,
         };
         %return self.exe_list.append(exe);
         return exe;
@@ -53,9 +55,43 @@ pub const Builder = struct {
 
             %return zig_args.append("build_exe"[0...]); // TODO issue #296
             %return zig_args.append(exe.root_src);
+
+            if (verbose) {
+                %return zig_args.append("--verbose"[0...]); // TODO issue #296
+            }
+
             %return zig_args.append("--name"[0...]); // TODO issue #296
             %return zig_args.append(exe.name);
 
+            switch (exe.target) {
+                Target.Native => {},
+                Target.Cross => |cross_target| {
+                    %return zig_args.append("--target-arch"[0...]); // TODO issue #296
+                    %return zig_args.append(targetArchName(cross_target.arch));
+
+                    %return zig_args.append("--target-os"[0...]); // TODO issue #296
+                    %return zig_args.append(targetOsName(cross_target.os));
+
+                    %return zig_args.append("--target-environ"[0...]); // TODO issue #296
+                    %return zig_args.append(targetEnvironName(cross_target.environ));
+                },
+            }
+
+            switch (exe.linker_script) {
+                LinkerScript.None => {},
+                LinkerScript.Embed => |script| {
+                    const tmp_file_name = "linker.ld.tmp"; // TODO issue #298
+                    io.writeFile(tmp_file_name, script, self.allocator)
+                        %% |err| debug.panic("unable to write linker script: {}\n", @errorName(err));
+                    %return zig_args.append("--linker-script"[0...]); // TODO issue #296
+                    %return zig_args.append(tmp_file_name[0...]); // TODO issue #296
+                },
+                LinkerScript.Path => |path| {
+                    %return zig_args.append("--linker-script"[0...]); // TODO issue #296
+                    %return zig_args.append(path);
+                },
+            }
+
             printInvocation(self.zig_exe, zig_args);
             var child = %return os.ChildProcess.spawn(self.zig_exe, zig_args.toSliceConst(), os.environ,
                 StdIo.Ignore, StdIo.Inherit, StdIo.Inherit, self.allocator);
@@ -72,9 +108,48 @@ pub const Builder = struct {
     }
 };
 
+const CrossTarget = struct {
+    arch: Arch,
+    os: Os,
+    environ: Environ,
+};
+
+const Target = enum {
+    Native,
+    Cross: CrossTarget,
+};
+
+const LinkerScript = enum {
+    None,
+    Embed: []const u8,
+    Path: []const u8,
+};
+
 const Exe = struct {
     root_src: []const u8,
     name: []const u8,
+    target: Target,
+    linker_script: LinkerScript,
+
+    fn setTarget(self: &Exe, target_arch: Arch, target_os: Os, target_environ: Environ) {
+        self.target = Target.Cross {
+            CrossTarget {
+                .arch = target_arch,
+                .os = target_os,
+                .environ = target_environ,
+            }
+        };
+    }
+
+    /// Exe keeps a reference to script for its lifetime or until this function
+    /// is called again.
+    fn setLinkerScriptContents(self: &Exe, script: []const u8) {
+        self.linker_script = LinkerScript.Embed { script };
+    }
+
+    fn setLinkerScriptPath(self: &Exe, path: []const u8) {
+        self.linker_script = LinkerScript.Path { path };
+    }
 };
 
 fn handleErr(err: error) -> noreturn {
@@ -88,3 +163,130 @@ fn printInvocation(exe_name: []const u8, args: &const List([]const u8)) {
     }
     %%io.stderr.printf("\n");
 }
+
+// TODO issue #299
+fn targetOsName(target_os: Os) -> []const u8 {
+    return switch (target_os) {
+        Os.freestanding => ([]const u8)("freestanding"),
+        Os.cloudabi => ([]const u8)("cloudabi"),
+        Os.darwin => ([]const u8)("darwin"),
+        Os.dragonfly => ([]const u8)("dragonfly"),
+        Os.freebsd => ([]const u8)("freebsd"),
+        Os.ios => ([]const u8)("ios"),
+        Os.kfreebsd => ([]const u8)("kfreebsd"),
+        Os.linux => ([]const u8)("linux"),
+        Os.lv2 => ([]const u8)("lv2"),
+        Os.macosx => ([]const u8)("macosx"),
+        Os.netbsd => ([]const u8)("netbsd"),
+        Os.openbsd => ([]const u8)("openbsd"),
+        Os.solaris => ([]const u8)("solaris"),
+        Os.windows => ([]const u8)("windows"),
+        Os.haiku => ([]const u8)("haiku"),
+        Os.minix => ([]const u8)("minix"),
+        Os.rtems => ([]const u8)("rtems"),
+        Os.nacl => ([]const u8)("nacl"),
+        Os.cnk => ([]const u8)("cnk"),
+        Os.bitrig => ([]const u8)("bitrig"),
+        Os.aix => ([]const u8)("aix"),
+        Os.cuda => ([]const u8)("cuda"),
+        Os.nvcl => ([]const u8)("nvcl"),
+        Os.amdhsa => ([]const u8)("amdhsa"),
+        Os.ps4 => ([]const u8)("ps4"),
+        Os.elfiamcu => ([]const u8)("elfiamcu"),
+        Os.tvos => ([]const u8)("tvos"),
+        Os.watchos => ([]const u8)("watchos"),
+        Os.mesa3d => ([]const u8)("mesa3d"),
+    };
+}
+
+// TODO issue #299
+fn targetArchName(target_arch: Arch) -> []const u8 {
+    return switch (target_arch) {
+        Arch.armv8_2a => ([]const u8)("armv8_2a"),
+        Arch.armv8_1a => ([]const u8)("armv8_1a"),
+        Arch.armv8 => ([]const u8)("armv8"),
+        Arch.armv8m_baseline => ([]const u8)("armv8m_baseline"),
+        Arch.armv8m_mainline => ([]const u8)("armv8m_mainline"),
+        Arch.armv7 => ([]const u8)("armv7"),
+        Arch.armv7em => ([]const u8)("armv7em"),
+        Arch.armv7m => ([]const u8)("armv7m"),
+        Arch.armv7s => ([]const u8)("armv7s"),
+        Arch.armv7k => ([]const u8)("armv7k"),
+        Arch.armv6 => ([]const u8)("armv6"),
+        Arch.armv6m => ([]const u8)("armv6m"),
+        Arch.armv6k => ([]const u8)("armv6k"),
+        Arch.armv6t2 => ([]const u8)("armv6t2"),
+        Arch.armv5 => ([]const u8)("armv5"),
+        Arch.armv5te => ([]const u8)("armv5te"),
+        Arch.armv4t => ([]const u8)("armv4t"),
+        Arch.armeb => ([]const u8)("armeb"),
+        Arch.aarch64 => ([]const u8)("aarch64"),
+        Arch.aarch64_be => ([]const u8)("aarch64_be"),
+        Arch.avr => ([]const u8)("avr"),
+        Arch.bpfel => ([]const u8)("bpfel"),
+        Arch.bpfeb => ([]const u8)("bpfeb"),
+        Arch.hexagon => ([]const u8)("hexagon"),
+        Arch.mips => ([]const u8)("mips"),
+        Arch.mipsel => ([]const u8)("mipsel"),
+        Arch.mips64 => ([]const u8)("mips64"),
+        Arch.mips64el => ([]const u8)("mips64el"),
+        Arch.msp430 => ([]const u8)("msp430"),
+        Arch.powerpc => ([]const u8)("powerpc"),
+        Arch.powerpc64 => ([]const u8)("powerpc64"),
+        Arch.powerpc64le => ([]const u8)("powerpc64le"),
+        Arch.r600 => ([]const u8)("r600"),
+        Arch.amdgcn => ([]const u8)("amdgcn"),
+        Arch.sparc => ([]const u8)("sparc"),
+        Arch.sparcv9 => ([]const u8)("sparcv9"),
+        Arch.sparcel => ([]const u8)("sparcel"),
+        Arch.s390x => ([]const u8)("s390x"),
+        Arch.tce => ([]const u8)("tce"),
+        Arch.thumb => ([]const u8)("thumb"),
+        Arch.thumbeb => ([]const u8)("thumbeb"),
+        Arch.i386 => ([]const u8)("i386"),
+        Arch.x86_64 => ([]const u8)("x86_64"),
+        Arch.xcore => ([]const u8)("xcore"),
+        Arch.nvptx => ([]const u8)("nvptx"),
+        Arch.nvptx64 => ([]const u8)("nvptx64"),
+        Arch.le32 => ([]const u8)("le32"),
+        Arch.le64 => ([]const u8)("le64"),
+        Arch.amdil => ([]const u8)("amdil"),
+        Arch.amdil64 => ([]const u8)("amdil64"),
+        Arch.hsail => ([]const u8)("hsail"),
+        Arch.hsail64 => ([]const u8)("hsail64"),
+        Arch.spir => ([]const u8)("spir"),
+        Arch.spir64 => ([]const u8)("spir64"),
+        Arch.kalimbav3 => ([]const u8)("kalimbav3"),
+        Arch.kalimbav4 => ([]const u8)("kalimbav4"),
+        Arch.kalimbav5 => ([]const u8)("kalimbav5"),
+        Arch.shave => ([]const u8)("shave"),
+        Arch.lanai => ([]const u8)("lanai"),
+        Arch.wasm32 => ([]const u8)("wasm32"),
+        Arch.wasm64 => ([]const u8)("wasm64"),
+        Arch.renderscript32 => ([]const u8)("renderscript32"),
+        Arch.renderscript64 => ([]const u8)("renderscript64"),
+    };
+}
+
+// TODO issue #299
+fn targetEnvironName(target_environ: Environ) -> []const u8 {
+    return switch (target_environ) {
+        Environ.gnu => ([]const u8)("gnu"),
+        Environ.gnuabi64 => ([]const u8)("gnuabi64"),
+        Environ.gnueabi => ([]const u8)("gnueabi"),
+        Environ.gnueabihf => ([]const u8)("gnueabihf"),
+        Environ.gnux32 => ([]const u8)("gnux32"),
+        Environ.code16 => ([]const u8)("code16"),
+        Environ.eabi => ([]const u8)("eabi"),
+        Environ.eabihf => ([]const u8)("eabihf"),
+        Environ.android => ([]const u8)("android"),
+        Environ.musl => ([]const u8)("musl"),
+        Environ.musleabi => ([]const u8)("musleabi"),
+        Environ.musleabihf => ([]const u8)("musleabihf"),
+        Environ.msvc => ([]const u8)("msvc"),
+        Environ.itanium => ([]const u8)("itanium"),
+        Environ.cygnus => ([]const u8)("cygnus"),
+        Environ.amdopencl => ([]const u8)("amdopencl"),
+        Environ.coreclr => ([]const u8)("coreclr"),
+    };
+}
std/debug.zig
@@ -28,7 +28,7 @@ pub coldcc fn panic(comptime format: []const u8, args: ...) -> noreturn {
         panicking = true;
     }
 
-    %%io.stderr.printf(format, args);
+    %%io.stderr.printf(format ++ "\n", args);
     %%printStackTrace();
 
     os.abort();
@@ -52,8 +52,8 @@ pub fn writeStackTrace(out_stream: &io.OutStream) -> %void {
                 .compile_unit_list = List(CompileUnit).init(&global_allocator),
             };
             const st = &stack_trace;
-            %return io.openSelfExe(&st.self_exe_stream);
-            defer st.self_exe_stream.close() %% {};
+            st.self_exe_stream = %return io.openSelfExe();
+            defer st.self_exe_stream.close();
 
             %return st.elf.openStream(&global_allocator, &st.self_exe_stream);
             defer st.elf.close();
std/io.zig
@@ -69,6 +69,27 @@ pub const OutStream = struct {
     buffer: [buffer_size]u8,
     index: usize,
 
+    /// `path` may need to be copied in memory to add a null terminating byte. In this case
+    /// a fixed size buffer of size std.os.max_noalloc_path_len is an attempted solution. If the fixed
+    /// size buffer is too small, and the provided allocator is null, error.NameTooLong is returned.
+    /// otherwise if the fixed size buffer is too small, allocator is used to obtain the needed memory.
+    /// Call close to clean up.
+    pub fn open(path: []const u8, allocator: ?&mem.Allocator) -> %OutStream {
+        switch (@compileVar("os")) {
+            Os.linux, Os.darwin, Os.macosx, Os.ios => {
+                const flags = system.O_LARGEFILE|system.O_WRONLY|system.O_CREAT|system.O_CLOEXEC|system.O_TRUNC;
+                const fd = %return os.posixOpen(path, flags, 0o666, allocator);
+                return OutStream {
+                    .fd = fd,
+                    .index = 0,
+                    .buffer = undefined,
+                };
+            },
+            else => @compileError("Unsupported OS"),
+        }
+
+    }
+
     pub fn writeByte(self: &OutStream, b: u8) -> %void {
         if (self.buffer.len == self.index) %return self.flush();
         self.buffer[self.index] = b;
@@ -76,6 +97,11 @@ pub const OutStream = struct {
     }
 
     pub fn write(self: &OutStream, bytes: []const u8) -> %void {
+        if (bytes.len >= buffer_size) {
+            %return self.flush();
+            return os.posixWrite(self.fd, bytes);
+        }
+
         var src_index: usize = 0;
 
         while (src_index < bytes.len) {
@@ -119,35 +145,15 @@ pub const OutStream = struct {
     }
 
     pub fn flush(self: &OutStream) -> %void {
-        while (true) {
-            const write_ret = system.write(self.fd, &self.buffer[0], self.index);
-            const write_err = system.getErrno(write_ret);
-            if (write_err > 0) {
-                return switch (write_err) {
-                    errno.EINTR  => continue,
-                    errno.EINVAL => unreachable,
-                    errno.EDQUOT => error.DiskQuota,
-                    errno.EFBIG  => error.FileTooBig,
-                    errno.EIO    => error.Io,
-                    errno.ENOSPC => error.NoSpaceLeft,
-                    errno.EPERM  => error.BadPerm,
-                    errno.EPIPE  => error.PipeFail,
-                    else         => error.Unexpected,
-                }
-            }
+        if (self.index != 0) {
+            %return os.posixWrite(self.fd, self.buffer[0...self.index]);
             self.index = 0;
-            return;
         }
     }
 
     pub fn close(self: &OutStream) {
-        while (true) {
-            const close_ret = system.close(self.fd);
-            const close_err = system.getErrno(close_ret);
-            if (close_err > 0 and close_err == errno.EINTR)
-                continue;
-            return;
-        }
+        assert(self.index == 0);
+        os.posixClose(self.fd);
     }
 };
 
@@ -156,65 +162,32 @@ pub const OutStream = struct {
 pub const InStream = struct {
     fd: i32,
 
+    /// `path` may need to be copied in memory to add a null terminating byte. In this case
+    /// a fixed size buffer of size std.os.max_noalloc_path_len is an attempted solution. If the fixed
+    /// size buffer is too small, and the provided allocator is null, error.NameTooLong is returned.
+    /// otherwise if the fixed size buffer is too small, allocator is used to obtain the needed memory.
     /// Call close to clean up.
-    pub fn open(is: &InStream, path: []const u8) -> %void {
+    pub fn open(path: []const u8, allocator: ?&mem.Allocator) -> %InStream {
         switch (@compileVar("os")) {
-            Os.linux, Os.darwin => {
-                while (true) {
-                    const result = system.open(path, system.O_LARGEFILE|system.O_RDONLY, 0);
-                    const err = system.getErrno(result);
-                    if (err > 0) {
-                        return switch (err) {
-                            errno.EINTR => continue,
-
-                            errno.EFAULT => unreachable,
-                            errno.EINVAL => unreachable,
-                            errno.EACCES => error.BadPerm,
-                            errno.EFBIG, errno.EOVERFLOW => error.FileTooBig,
-                            errno.EISDIR => error.IsDir,
-                            errno.ELOOP => error.SymLinkLoop,
-                            errno.EMFILE => error.ProcessFdQuotaExceeded,
-                            errno.ENAMETOOLONG => error.NameTooLong,
-                            errno.ENFILE => error.SystemFdQuotaExceeded,
-                            errno.ENODEV => error.NoDevice,
-                            errno.ENOENT => error.PathNotFound,
-                            errno.ENOMEM => error.NoMem,
-                            errno.ENOSPC => error.NoSpaceLeft,
-                            errno.ENOTDIR => error.NotDir,
-                            errno.EPERM => error.BadPerm,
-                            else => error.Unexpected,
-                        }
-                    }
-                    is.fd = i32(result);
-                    return;
-                }
+            Os.linux, Os.darwin, Os.macosx, Os.ios => {
+                const flags = system.O_LARGEFILE|system.O_RDONLY;
+                const fd = %return os.posixOpen(path, flags, 0, allocator);
+                return InStream {
+                    .fd = fd,
+                };
             },
-            else => @compileError("unsupported OS"),
+            else => @compileError("Unsupported OS"),
         }
-
     }
 
     /// Upon success, the stream is in an uninitialized state. To continue using it,
     /// you must use the open() function.
-    pub fn close(is: &InStream) -> %void {
+    pub fn close(self: &InStream) {
         switch (@compileVar("os")) {
-            Os.linux, Os.darwin => {
-                while (true) {
-                    const close_ret = system.close(is.fd);
-                    const close_err = system.getErrno(close_ret);
-                    if (close_err > 0) {
-                        return switch (close_err) {
-                            errno.EINTR => continue,
-
-                            errno.EIO => error.Io,
-                            errno.EBADF => error.BadFd,
-                            else => error.Unexpected,
-                        }
-                    }
-                    return;
-                }
+            Os.linux, Os.darwin, Os.macosx, Os.ios => {
+                os.posixClose(self.fd);
             },
-            else => @compileError("unsupported OS"),
+            else => @compileError("Unsupported OS"),
         }
     }
 
@@ -373,15 +346,28 @@ pub const InStream = struct {
     }
 };
 
-pub fn openSelfExe(stream: &InStream) -> %void {
+pub fn openSelfExe() -> %InStream {
     switch (@compileVar("os")) {
         Os.linux => {
-            %return stream.open("/proc/self/exe");
+            return InStream.open("/proc/self/exe", null);
         },
         Os.darwin => {
-            %%stderr.printf("TODO: openSelfExe on Darwin\n");
-            os.abort();
+            debug.panic("TODO: openSelfExe on Darwin");
         },
-        else => @compileError("unsupported os"),
+        else => @compileError("Unsupported OS"),
     }
 }
+
+/// `path` may need to be copied in memory to add a null terminating byte. In this case
+/// a fixed size buffer of size std.os.max_noalloc_path_len is an attempted solution. If the fixed
+/// size buffer is too small, and the provided allocator is null, error.NameTooLong is returned.
+/// otherwise if the fixed size buffer is too small, allocator is used to obtain the needed memory.
+pub fn writeFile(path: []const u8, data: []const u8, allocator: ?&mem.Allocator) -> %void {
+    // TODO have an unbuffered File abstraction and use that here.
+    // Then a buffered out stream abstraction can go on top of that for
+    // use cases like stdout and stderr.
+    var out_stream = %return OutStream.open(path, allocator);
+    defer out_stream.close();
+    %return out_stream.write(data);
+    %return out_stream.flush();
+}