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1aece29d533f8f5749ac0700bc747dd4d8225cdc
ww/selfhost/cmd/w6a/main.combined.ww
Hojun-Cho 1aece29d53 lib/os: revert at enum to three top-level defs (post-#24) 
cf24af8 fixed the negative-literal def DATA-emit gap that forced
the `at` enum bundle. Revert to Hare's shape: three export def
AT_FDCWD / AT_SYMLINK_NOFOLLOW / AT_EMPTY_PATH at i32, mirroring
ref/hare/sys/+linux/types.ha:45-51. Values from <linux/fcntl.h>:
-100 / 256 / 4096.

Four call sites (stat / lstat / fstat / exists) updated.
2026-05-16 03:09:49 +09:00

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// MODULE: os
// os — process and filesystem facade. The body of each call lands
// either in libwwrt.a (rt_syscall trampoline) or libc bindings,
// depending on how the program was linked.
@symbol("rt_syscall") fn syscall0(num: nr) i64;
@symbol("rt_syscall") fn syscall1(num: nr, a: i64) i64;
@symbol("rt_syscall") fn syscall2(num: nr, a: i64, b: i64) i64;
@symbol("rt_syscall") fn syscall3(num: nr, a: i64, b: i64, c: i64) i64;
@symbol("rt_syscall") fn syscall4(num: nr, a: i64, b: i64, c: i64, d: i64) i64;
// alloc / free — runtime mmap-backed page allocator. Untyped:
// `alloc(n)` returns a `*void` and `free(p, n)` requires the byte
// count back because rt_free is munmap-based and doesn't track
// mapping sizes (the kernel needs the length to release the
// reservation).
//
// Diverges from Hare. Hare exposes `alloc` / `free` as typed
// language builtins (`alloc(value, cap)?` / `free(ptr)`) that the
// compiler lowers to rt::malloc/rt::free; ww has no such builtins,
// so the rt-symbol surface is exposed directly. Stdlib callers
// that need a typed allocation pattern wrap this with a cast plus
// a stored capacity (see [[strings.dup]], [[memio.dynamic]]).
//
// OOM: rt_alloc is a bare mmap(MAP_ANON|MAP_PRIVATE) wrapper with
// no error path. The raw Linux mmap syscall returns a negative
// errno cast to `*void` on failure (e.g. `(void*)-12` for ENOMEM);
// the `MAP_FAILED` (`(void*)-1`) value is a libc-wrapper convention
// that rt_alloc doesn't apply. Neither `== nil` nor `== (void*)-1`
// catches it; any deref of such a return faults. Today the stdlib
// does not check; OOM faults on first dereference. A typed
// fallible variant is a future task.
@symbol("rt_alloc") export fn alloc(n: u64) *void;
@symbol("rt_free") export fn free(p: *void, n: u64) void;
@symbol("rt_abort") fn abort(msg: str) void;
// Hare-style runtime check. Caller passes a message that's printed
// to stderr before exit(1).
export fn assert(cond: bool, msg: str) void = {
if (!cond) { abort(msg); };
};
// Linux amd64 syscall numbers. Internal to this module — passed as
// the first arg of syscall0..4 via libwwrt's rt_syscall trampoline.
// `nr` is the type so the call sites can't accidentally pass an
// arbitrary i64 (`syscall1(0i64, ...)` no longer typechecks).
type nr = enum i64 {
READ = 0,
WRITE = 1,
OPEN = 2,
CLOSE = 3,
LSEEK = 8,
ACCESS = 21,
DUP2 = 33,
GETPID = 39,
FORK = 57,
EXECVE = 59,
EXIT = 60,
WAIT4 = 61,
MKDIR = 83,
RMDIR = 84,
UNLINK = 87,
GETCWD = 79,
GETDENTS64 = 217,
NEWFSTATAT = 262,
};
// open(2) flags. Linux values, matching <fcntl.h>. Hare names them
// `fs::flag::RDONLY` etc; we use the same leaf names so callers say
// `os.flag.RDONLY` and `os.flag.WRONLY | os.flag.CREATE`.
export type flag = enum i32 {
RDONLY = 0,
WRONLY = 1,
RDWR = 2,
CREATE = 64, // 0x40
EXCL = 128, // 0x80 — pair with CREATE to fail on existing path
TRUNC = 512, // 0x200
};
// lseek(2) whence. Hare names it `io::whence`.
export type whence = enum i32 {
SET = 0,
CUR = 1,
END = 2,
};
export fn exit(code: i32) void = {
syscall1(nr.EXIT, code: i64);
};
// Raw, non-fallible primitives. These return Linux's int conventions
// (negative = -errno, non-negative = bytes/fd/etc). Callers wanting a
// Hare-style fallible API use the wrappers below.
export fn write(fd: i32, buf: *u8, n: u64) i64 = {
return syscall3(nr.WRITE, fd: i64, buf: i64, n: i64);
};
export fn read(fd: i32, buf: *u8, n: u64) i64 = {
return syscall3(nr.READ, fd: i64, buf: i64, n: i64);
};
export fn close(fd: i32) i32 = {
return syscall1(nr.CLOSE, fd: i64): i32;
};
// dup2(2): make `newfd` refer to the same description as `oldfd`,
// closing `newfd` first if open. Returns `newfd` on success or a
// negative errno. Used by w6c_ww to redirect stdout into an output
// file without changing the cgen emit path.
export fn dup2(oldfd: i32, newfd: i32) i32 = {
return syscall2(nr.DUP2, oldfd: i64, newfd: i64): i32;
};
// Fallible wrappers. The error variant is `oserror` (an i64 carrying
// -errno). The sum type makes success/failure explicit and lets
// callers `?` the result up the stack.
export fn tryread(fd: i32, buf: *u8, n: u64) (i64 | oserror) = {
let r: i64 = read(fd, buf, n);
if (r < 0) { return r: oserror; };
return r;
};
export fn trywrite(fd: i32, buf: *u8, n: u64) (i64 | oserror) = {
let r: i64 = write(fd, buf, n);
if (r < 0) { return r: oserror; };
return r;
};
// open — Linux open(2). Path must be NUL-terminated; callers using ww
// `str` must ensure the bytes are followed by a 0 byte (literals are,
// arena-copied paths usually are by construction). Returns -errno on
// failure, fd otherwise. Higher-level callers prefer `tryopen`.
export fn open(path: *u8, flags: flag, mode: i32) i32 = {
return syscall3(nr.OPEN, path: i64, (flags as i32): i64, mode: i64): i32;
};
export fn tryopen(path: *u8, flags: flag, mode: i32) (i32 | oserror) = {
let fd: i32 = open(path, flags, mode);
if (fd < 0) { return fd: i64: oserror; };
return fd;
};
// lseek — set/inspect the fd's position. Returns the new offset or
// a negative errno. We use this for fstat-free file-size discovery
// (open ⇒ lseek to end ⇒ lseek back).
export fn lseek(fd: i32, off: i64, w: whence) i64 = {
return syscall3(nr.LSEEK, fd: i64, off, (w as i32): i64);
};
// oserror — the underlying errno from a failed syscall, as a
// negative i64 (Linux's int convention; e.g. -2 = ENOENT). The
// `!`-flagged alias makes ?-propagation pick this variant as the
// error half of any (T | oserror) shape. Hare's analogue is
// errors::errno carried inside io::error.
export type oserror = !i64;
// filesize — byte length of an open fd via lseek-to-end-and-back.
export fn filesize(fd: i32) (i64 | oserror) = {
let end: i64 = lseek(fd, 0i64, whence.END);
if (end < 0) { return end: oserror; };
let r: i64 = lseek(fd, 0i64, whence.SET);
if (r < 0) { return r: oserror; };
return end;
};
// readall — keep reading until `n` bytes have arrived or the fd
// closes early. Hare name (io::readall); the buffer is caller-
// supplied, matching the Plan 9 subset convention.
export fn readall(fd: i32, buf: *u8, n: u64) (i64 | oserror) = {
let got: u64 = 0u64;
for (got < n) {
let r: i64 = read(fd, buf + got, n - got);
if (r < 0) { return r: oserror; };
if (r == 0) { return got: i64; }; // short read: caller decides
got += r: u64;
};
return got: i64;
};
// writeall — keep writing until `n` bytes have been accepted or the
// fd refuses progress. Hare name (io::writeall).
export fn writeall(fd: i32, buf: *u8, n: u64) (i64 | oserror) = {
let sent: u64 = 0u64;
for (sent < n) {
let r: i64 = write(fd, buf + sent, n - sent);
if (r < 0) { return r: oserror; };
if (r == 0) { return sent: i64; };
sent += r: u64;
};
return sent: i64;
};
// ---- process and filesystem helpers used by the `ww` driver ----------
// access(2): returns 0 if the file is reachable, negative errno
// otherwise. mode is the bitset described in <unistd.h> (F_OK=0).
export fn access(path: *u8, mode: i32) i32 = {
return syscall2(nr.ACCESS, path: i64, mode: i64): i32;
};
// remove — unlink(2). Hare name; the underlying syscall is unlink(2).
export fn remove(path: *u8) i32 = {
return syscall1(nr.UNLINK, path: i64): i32;
};
// mkdir — mkdir(2). Path must be NUL-terminated. Mode is the unix
// permission bitset (e.g. 0o700). Returns 0 on success, negative
// errno otherwise. Hare name (os::mkdir).
export fn mkdir(path: *u8, mode: i32) i32 = {
return syscall2(nr.MKDIR, path: i64, mode: i64): i32;
};
// rmdir — rmdir(2). Path must be NUL-terminated. Returns 0 on
// success, negative errno otherwise. Hare name (os::rmdir).
export fn rmdir(path: *u8) i32 = {
return syscall1(nr.RMDIR, path: i64): i32;
};
// mkdirs — recursive mkdir. Creates `path` and any non-existent
// parent directories with the given mode. EEXIST is silently
// accepted (matches Hare's `errors::exists` skip in os::mkdirs);
// any other syscall failure surfaces as `oserror`.
//
// `path` must be NUL-terminated AND its bytes must be writable —
// mkdirs temporarily replaces '/' separators with NUL while
// invoking [[mkdir]] on each prefix, then restores them. Pointing
// `path` at a string literal will segfault. Callers hold the bytes
// in a writable buffer (rt_alloc'd, a static `[N]u8`, etc.) — same
// precedent as [[temp.named]]'s pathbuf.
//
// Mirrors Hare's os::mkdirs (recursive variant of os::mkdir).
export fn mkdirs(path: *u8, mode: i32) (void | oserror) = {
// Find the path length (excluding trailing NUL).
let n: i32 = 0;
for (path[n] != 0u8) { n += 1; };
if (n == 0) { return; };
// Walk forward; at each '/' boundary, NUL-terminate the prefix,
// mkdir it, restore the slash, continue. Skip index 0 so a
// leading '/' on absolute paths doesn't trigger an empty mkdir.
let i: i32 = 1;
for (i < n) {
if (path[i] == 47u8) { // '/'
path[i] = 0u8;
let r: i32 = mkdir(path, mode);
path[i] = 47u8;
if (r < 0) {
if (r != -17) { return r: i64: oserror; };
};
};
i += 1;
};
// mkdir the full path.
let r: i32 = mkdir(path, mode);
if (r < 0) {
if (r != -17) { return r: i64: oserror; };
};
return;
};
// getpid(2). Used by the driver to mint unique scratch paths.
export fn getpid() i32 = {
return syscall0(nr.GETPID): i32;
};
// fork(2): 0 in the child, child pid in the parent, negative errno
// on failure.
export fn fork() i32 = {
return syscall0(nr.FORK): i32;
};
// execve(2): on success, does not return.
export fn execve(path: *u8, argv: **u8, envp: **u8) i32 = {
return syscall3(nr.EXECVE, path: i64, argv: i64, envp: i64): i32;
};
// wait4(2): wait for `pid` (or any child if -1), store status in
// `*status`, return the pid that ended (or negative errno).
export fn wait4(pid: i32, status: *i32, options: i32, rusage: *void) i32 = {
return syscall4(nr.WAIT4, pid: i64, status: i64,
options: i64, rusage: i64): i32;
};
// getcwd(2) — Linux flavour. Writes the NUL-terminated cwd into `buf`
// and returns the number of bytes written (including the NUL), or a
// negative errno. The driver uses it to expand `.` to the cwd's
// basename for `ww build` / `ww test`.
export fn getcwd(buf: *u8, n: u64) i64 = {
return syscall2(nr.GETCWD, buf: i64, n: i64);
};
// getdents64(2) — Linux directory enumeration. The fd must be opened
// with O_RDONLY on a directory. `buf` receives a packed sequence of
// linux_dirent64 records:
//
// struct linux_dirent64 {
// u64 d_ino; // 0..7
// i64 d_off; // 8..15
// u16 d_reclen; // 16..17 — total bytes for this record
// u8 d_type; // 18 — DT_REG/DT_DIR/...
// u8 d_name[]; // 19.. — NUL-terminated name + padding
// };
//
// Returns bytes written into `buf` (advance by d_reclen to walk),
// 0 at end-of-directory, or a negative errno.
export fn getdents64(fd: i32, buf: *u8, n: u64) i64 = {
return syscall3(nr.GETDENTS64, fd: i64, buf: i64, n: i64);
};
// ---- environment ------------------------------------------------------
// rt_envp — runtime-side getter. rt/start.s captures envp into a DATAW
// slot before calling main; this binding lifts the captured pointer
// into ww. Same FFI shape as rt_syscall / rt_alloc / rt_abort: a TEXT
// symbol the linker resolves. The returned `**u8` is a NUL-terminated
// table of `*u8` entries, each pointing at a NUL-terminated
// "NAME=VALUE" byte sequence.
//
// We don't expose `rtenvp` directly; [[getenv]] is the only consumer.
@symbol("rt_envp") fn rtenvp() **u8;
// getenv — POSIX getenv. Returns a borrowed `str` view over the value
// bytes of the named environment variable, or void if the name is not
// present. The view is valid for the process lifetime — the bytes
// live in the kernel-supplied envp table at process entry. A future
// `setenv` (separate task) that grows the table behind the scenes
// would invalidate prior views; v1 has no setenv, so callers can
// hold the view indefinitely.
//
// Mirrors Hare's os::tryenv shape (returns void rather than panicking
// on missing). Hare also ships os::getenv (`(str | void)`) and
// os::mustenv (panic-on-missing); ww collapses to the single
// `(str | void)` form for now — consumers wanting "must" semantics
// abort at the call site.
//
// Algorithm: walk the NUL-pointer-terminated `environ` table doing a
// "name=" prefix match against each entry, byte-wise. NUL inside
// `name` would never match a real env var (env var names cannot
// contain '\0'), so we don't filter — POSIX puts that responsibility
// on the caller.
export fn getenv(name: str) (str | void) = {
let envp: **u8 = rtenvp();
let i: i32 = 0;
for (true) {
let entry: *u8 = envp[i];
if (entry == nil: *u8) { return; };
let j: i32 = 0;
let matched: bool = true;
for (j < name.len) {
if (entry[j] == 0u8) { matched = false; break; };
if (entry[j] != name[j]) { matched = false; break; };
j += 1;
};
if (matched) {
if (entry[name.len] == 61u8) { // '='
let val: *u8 = entry + ((name.len + 1): u64);
let n: i32 = 0;
for (val[n] != 0u8) { n += 1; };
let r: str;
r.ptr = val;
r.len = n;
return r;
};
};
i += 1;
};
return;
};
// ---- stat / lstat / fstat / exists -----------------------------------
//
// Ports of Hare's stat family (ref/hare/fs/fs.ha:172,196 +
// ref/hare/sys/+linux/stat.ha:24-58). The Hare surface returns
// `filestat` by value; ww's cgreturn ABI tops out at 24B today (see
// STATUS task #21) and filestat is 80B, so [[stat]] / [[lstat]] /
// [[fstat]] take an out-parameter and return `(void | oserror)`.
// Re-evaluate the by-value shape when full sret lands.
//
// `filestat`, `mode`, and `stat_mask` live in lib/os because ww has
// no lib/fs yet; Hare puts them in `fs::`. These types graduate to
// lib/fs when that module ships — callers should expect a future
// re-export.
//
// Underlying syscall is SYS_newfstatat (262), which unifies
// stat/lstat/fstat through the `dirfd + flags` triple:
// stat = newfstatat(AT_FDCWD, path, 0)
// lstat = newfstatat(AT_FDCWD, path, AT_SYMLINK_NOFOLLOW)
// fstat = newfstatat(fd, "", AT_EMPTY_PATH)
// Avoiding SYS_statx — its 256B variable layout would buy btime,
// but Hare's filestat doesn't expose btime either, so we stay on
// the simpler 144B kernel struct.
// fstatat(2) flag values. Linux constants from <linux/fcntl.h>.
// Names mirror Hare's ref/hare/sys/+linux/types.ha:45-51 (capital-
// AT_ prefix, top-level `def`s).
export def AT_FDCWD: i32 = -100;
export def AT_SYMLINK_NOFOLLOW: i32 = 256; // 0x100
export def AT_EMPTY_PATH: i32 = 4096; // 0x1000
// mode — file-mode bits. Mirrors Hare's fs::mode (ref/hare/fs/
// types.ha:63). Permission bits are the standard Unix octal subset;
// type bits live in the S_IFMT = 0o170000 region. Type-bit test:
//
// let t: u32 = (fi.mode as u32) & 61440u32; // 0o170000 mask
// if (t == os.mode.DIR as u32) { /* directory */ };
//
// Numeric values are octal in Hare's source; ww has no octal
// literals so they're written as decimal with the octal in a
// trailing comment.
export type mode = enum u32 {
// permission bits
USER_RWX = 448u32, // 0o700
USER_RW = 384u32, // 0o600
USER_RX = 320u32, // 0o500
USER_R = 256u32, // 0o400
USER_W = 128u32, // 0o200
USER_X = 64u32, // 0o100
GROUP_RWX = 56u32, // 0o070
GROUP_RW = 48u32, // 0o060
GROUP_RX = 40u32, // 0o050
GROUP_R = 32u32, // 0o040
GROUP_W = 16u32, // 0o020
GROUP_X = 8u32, // 0o010
OTHER_RWX = 7u32, // 0o007
OTHER_RW = 6u32, // 0o006
OTHER_RX = 5u32, // 0o005
OTHER_R = 4u32, // 0o004
OTHER_W = 2u32, // 0o002
OTHER_X = 1u32, // 0o001
SETUID = 2048u32, // 0o4000
SETGID = 1024u32, // 0o2000
STICKY = 512u32, // 0o1000
// file-type bits (S_IFMT mask = 0o170000 = 61440)
UNKNOWN = 0u32,
FIFO = 4096u32, // 0o010000
CHR = 8192u32, // 0o020000
DIR = 16384u32, // 0o040000
BLK = 24576u32, // 0o060000
REG = 32768u32, // 0o100000
LINK = 40960u32, // 0o120000
SOCK = 49152u32, // 0o140000
};
// stat_mask — which filestat fields the call populated. Mirrors
// Hare's fs::stat_mask (ref/hare/fs/types.ha:129). newfstatat fills
// every field, so [[stat]] / [[lstat]] / [[fstat]] always set all
// seven bits OR-folded (see [[fillfilestat]]); per-bit testing is
// the documented sparse-backend pattern (cf. Hare's fs::fs network
// backends that only populate mtime+size).
export type stat_mask = enum u32 {
UID = 1u32,
GID = 2u32,
SIZE = 4u32,
INODE = 8u32,
ATIME = 16u32,
MTIME = 32u32,
CTIME = 64u32,
};
// timespec — {sec, nsec} pair, matching Hare's time::instant
// (ref/hare/time/types.ha). Local to lib/os; graduates to
// lib/time.instant when lib/time and lib/fs ship. Same byte layout
// (i64+i64 = 16B) so a future migration is field-rename only.
export type timespec = struct {
sec: i64,
nsec: i64,
};
// filestat — Hare's fs::filestat (ref/hare/fs/types.ha:141). 80
// bytes. See module-header note re: graduation to lib/fs.
export type filestat = struct {
mask: stat_mask, // 0 (4)
mode: mode, // 4 (4)
uid: u32, // 8 (4)
gid: u32, // 12 (4)
sz: u64, // 16 (8)
inode: u64, // 24 (8)
atime: timespec, // 32 (16)
mtime: timespec, // 48 (16)
ctime: timespec, // 64 (16) — ends at 80
};
// kstat — x86_64 kernel `struct stat` layout. Mirrors
// arch/x86/include/uapi/asm/stat.h (`__kernel_ulong_t`-keyed
// fields). 144 bytes. Module-internal; SYS_newfstatat writes into
// this buffer and the public stat fns then copy the bits into the
// Hare-shaped [[filestat]].
//
// Mode is typed as the public [[mode]] enum (rather than raw u32)
// so [[fillfilestat]]'s `out.mode = k.mode` needs no cast. Cstage
// emits a redundant `MOVL AX, AX` on u32 → enum-u32 casts that
// wwstage skips (task #25); the in-tree shape sidesteps it.
// Identical byte layout (both 4B at offset 24).
type kstat = struct {
dev: u64, // 0
ino: u64, // 8
nlink: u64, // 16
mode: mode, // 24
uid: u32, // 28
gid: u32, // 32
pad0: u32, // 36
rdev: u64, // 40
sz: i64, // 48
blksize: i64, // 56
blocks: i64, // 64
atime_sec: i64, // 72
atime_nsec: i64, // 80
mtime_sec: i64, // 88
mtime_nsec: i64, // 96
ctime_sec: i64, // 104
ctime_nsec: i64, // 112
unused0: i64, // 120
unused1: i64, // 128
unused2: i64, // 136 — ends at 144
};
// emptypath — single-NUL byte used as the `pathname` arg to
// newfstatat with AT_EMPTY_PATH. The kernel requires a non-NULL
// pointer to a zero-length C string, NOT a null pointer. Bytes are
// read-only from the kernel's view; ww has no module-level const so
// this is a writable `let`.
let emptypath: [1]u8 = [0u8];
// fillfilestat — copy a 144B kstat into the 80B Hare-shaped
// filestat. Internal helper used by all three public entry points.
// Mirrors Hare's st_to_filestat (ref/hare/os/+linux/dirfdfs.ha:259):
// newfstatat populates every field, so the mask is the OR-fold of
// all seven Hare stat_mask bits.
fn fillfilestat(out: *filestat, k: *kstat) void = {
out.mask = stat_mask.UID | stat_mask.GID | stat_mask.SIZE
| stat_mask.INODE | stat_mask.ATIME | stat_mask.MTIME
| stat_mask.CTIME;
out.mode = k.mode;
out.uid = k.uid;
out.gid = k.gid;
out.sz = k.sz: u64;
out.inode = k.ino;
out.atime.sec = k.atime_sec;
out.atime.nsec = k.atime_nsec;
out.mtime.sec = k.mtime_sec;
out.mtime.nsec = k.mtime_nsec;
out.ctime.sec = k.ctime_sec;
out.ctime.nsec = k.ctime_nsec;
};
// stat — fill *out with metadata for `path`. Follows symlinks.
// `path` must be NUL-terminated (lib/os convention; see task #23
// for a planned `path: str` migration).
//
// Mirrors Hare's sys::stat (ref/hare/sys/+linux/stat.ha:51) modulo
// the out-param shape forced by the cgreturn 24B cap. Note: Hare's
// higher-level fs::stat (ref/hare/fs/fs.ha:172) instead has lstat
// semantics — we follow sys::stat's POSIX-stat behavior here.
export fn stat(out: *filestat, path: *u8) (void | oserror) = {
let k: kstat;
let r: i64 = syscall4(nr.NEWFSTATAT,
AT_FDCWD: i64, path: i64, (&k): i64, 0i64);
if (r < 0) { return r: oserror; };
fillfilestat(out, &k);
};
// lstat — like [[stat]] but does NOT follow a terminal symlink.
// Mirrors Hare's sys::lstat (ref/hare/sys/+linux/stat.ha:57).
export fn lstat(out: *filestat, path: *u8) (void | oserror) = {
let k: kstat;
let r: i64 = syscall4(nr.NEWFSTATAT,
AT_FDCWD: i64, path: i64, (&k): i64,
AT_SYMLINK_NOFOLLOW: i64);
if (r < 0) { return r: oserror; };
fillfilestat(out, &k);
};
// fstat — like [[stat]] but addresses the file by fd. Uses
// newfstatat(fd, "", AT_EMPTY_PATH); the kernel resolves the fd
// directly. Mirrors Hare's sys::fstat (ref/hare/sys/+linux/stat.ha:54).
export fn fstat(out: *filestat, fd: i32) (void | oserror) = {
let k: kstat;
let r: i64 = syscall4(nr.NEWFSTATAT,
fd: i64, (&emptypath[0]): i64, (&k): i64,
AT_EMPTY_PATH: i64);
if (r < 0) { return r: oserror; };
fillfilestat(out, &k);
};
// exists — true if `path` resolves to anything (regular file,
// directory, symlink, ...). Stat-shaped (Hare's `fs::exists`,
// ref/hare/fs/fs.ha:196) — no separate syscall. Symlinks are
// followed; a dangling symlink is `false`.
//
// Race warning: prefer "open and handle the error" over "exists
// then open" in real code (Hare's docstring carries the same
// note). The race is unavoidable in this shape.
//
// Goes through SYS_newfstatat directly rather than match'ing on
// [[stat]]'s `(void | oserror)` return. Functionally identical;
// the direct shape sidesteps a cstage/wwstage cgen disagreement
// on the slot size of `(void | oserror)` (cstage 16B, wwstage 24B
// — same class as STATUS #22, surfaced first time a match on this
// shape combined with an 80B local-struct local frame). Use the
// match shape once #22 lands.
export fn exists(path: *u8) bool = {
let k: kstat;
let r: i64 = syscall4(nr.NEWFSTATAT,
AT_FDCWD: i64, path: i64, (&k): i64, 0i64);
return r >= 0i64;
};
// MODULE: wcc
// selfhost/cmd/wcc/mem.ww — port of cmd/wcc/mem.c.
//
// Bump arena allocator. Backed by the runtime page allocator
// (rt_alloc / rt_free), no libc. Each chunk is mmap'd; when the
// current chunk runs out we link a fresh one. Freeing the arena
// unmaps the chain.
//
// Memory handed out is 16-byte aligned. The C version under
// cmd/wcc/ is retained until the three-stage bootstrap diffs clean.
use os;
def ALIGN: u64 = 16u64;
def INIT_CHUNK: u64 = 65536u64;
def MAX_CHUNK: u64 = 4194304u64;
def ARENA_SZ: u64 = 48u64; // sizeof(arena), kept in sync below
type arena = struct {
buf: *u8,
off: u64,
cap: u64,
next: *arena,
total: u64,
};
fn roundup(n: u64, a: u64) u64 = {
return (n + a - 1u64) & ~(a - 1u64);
};
export fn newarena() *arena = {
let a: *arena = os.alloc(ARENA_SZ): *arena;
a.buf = os.alloc(INIT_CHUNK): *u8;
a.off = 0u64;
a.cap = INIT_CHUNK;
a.next = nil;
a.total = 0u64;
return a;
};
// Grow: link a fresh chunk in front of the head. We push the old
// chunk into `next` so the head always describes the current bump
// region. Chunk size doubles up to MAX_CHUNK.
fn grow(a: *arena, need: u64) bool = {
let want: u64 = a.cap * 2u64;
if (want < need) { want = need; };
if (want > MAX_CHUNK) { want = MAX_CHUNK; };
if (want < need) { return false; }; // single allocation too big
let old: *arena = os.alloc(ARENA_SZ): *arena;
old.buf = a.buf;
old.off = a.off;
old.cap = a.cap;
old.next = a.next;
old.total = 0u64;
a.buf = os.alloc(want): *u8;
a.off = 0u64;
a.cap = want;
a.next = old;
return true;
};
export fn amalloc(a: *arena, n: u64) *void = {
let need: u64 = roundup(n, ALIGN);
if (need > a.cap - a.off) {
if (!grow(a, need)) { return nil; };
};
let p: *u8 = a.buf + a.off;
a.off += need;
a.total += need;
// Zero the region. Plan 9 amalloc zeroes; we mirror that here so
// the checker can assume freshly allocated nodes start at 0.
let i: u64 = 0u64;
for (i < need) {
p[i] = 0u8;
i += 1u64;
};
return p: *void;
};
// astrndup — copy `n` bytes into the arena and produce a NUL-terminated
// view. Returns a `str` whose ptr is arena-owned and whose len is `n`
// (the trailing NUL is past `len`, so callers reading exactly n bytes
// see no padding). Used by the lexer to capture token text.
export fn astrndup(a: *arena, src: *u8, n: u64) str = {
let p: *u8 = amalloc(a, n + 1u64): *u8;
let i: u64 = 0u64;
for (i < n) {
p[i] = src[i];
i += 1u64;
};
p[n] = 0u8;
let r: str;
r.ptr = p;
r.len = n: i32;
return r;
};
export fn freearena(a: *arena) void = {
for (a != nil) {
let next: *arena = a.next;
os.free(a.buf: *void, a.cap);
os.free(a: *void, ARENA_SZ);
a = next;
};
};
// MODULE: w6a
// selfhost/cmd/w6a/types.ww — types + constants shared across the
// w6a port. Mirrors cmd/w6a/a.h and cmd/w6c/6.out.h.
use mem;
// ---- registers + operand kinds (from 6.out.h) -------------------------
// These must stay numerically aligned with the C enum so that ww-cgen
// output (which reads them via `D_AX(SB)` etc.) lands on the same
// integers when read by ww-w6a.
def D_NONE: i32 = 0;
def D_AX: i32 = 1;
def D_CX: i32 = 2;
def D_DX: i32 = 3;
def D_BX: i32 = 4;
def D_SP: i32 = 5;
def D_BP: i32 = 6;
def D_SI: i32 = 7;
def D_DI: i32 = 8;
def D_R8: i32 = 9;
def D_R9: i32 = 10;
def D_R10: i32 = 11;
def D_R11: i32 = 12;
def D_R12: i32 = 13;
def D_R13: i32 = 14;
def D_R14: i32 = 15;
def D_R15: i32 = 16;
def D_X0: i32 = 17;
def D_X1: i32 = 18;
def D_X2: i32 = 19;
def D_X3: i32 = 20;
def D_X4: i32 = 21;
def D_X5: i32 = 22;
def D_X6: i32 = 23;
def D_X7: i32 = 24;
def D_X8: i32 = 25;
def D_X9: i32 = 26;
def D_X10: i32 = 27;
def D_X11: i32 = 28;
def D_X12: i32 = 29;
def D_X13: i32 = 30;
def D_X14: i32 = 31;
def D_X15: i32 = 32;
def D_PSP: i32 = 33;
def D_PFP: i32 = 34;
def D_PSB: i32 = 35;
def D_CONST: i32 = 36;
def D_BRANCH: i32 = 37;
def D_EXTERN: i32 = 38;
def D_INDIR: i32 = 39;
// ---- opcodes ----------------------------------------------------------
def A_NOP: i32 = 0;
def A_TEXT: i32 = 1;
def A_DATA: i32 = 2;
def A_GLOBL: i32 = 3;
def A_END: i32 = 4;
def A_MOVQ: i32 = 5;
def A_MOVL: i32 = 6;
def A_MOVB: i32 = 7;
def A_MOVZBQ: i32 = 8;
def A_MOVSXD: i32 = 9;
def A_MOVW: i32 = 62;
def A_MOVZWQ: i32 = 63;
def A_MOVSWQ: i32 = 64;
def A_MOVSBQ: i32 = 65;
def A_MOVSD: i32 = 10;
def A_ADDSD: i32 = 11;
def A_SUBSD: i32 = 12;
def A_MULSD: i32 = 13;
def A_DIVSD: i32 = 14;
def A_UCOMISD: i32 = 15;
def A_CVTTSD2SI: i32 = 16;
def A_CVTSI2SD: i32 = 17;
def A_MOVSS: i32 = 18;
def A_ADDSS: i32 = 19;
def A_SUBSS: i32 = 20;
def A_MULSS: i32 = 21;
def A_DIVSS: i32 = 22;
def A_UCOMISS: i32 = 23;
def A_CVTTSS2SI: i32 = 24;
def A_CVTSI2SS: i32 = 25;
def A_CVTSD2SS: i32 = 26;
def A_CVTSS2SD: i32 = 27;
def A_ADDQ: i32 = 28;
def A_SUBQ: i32 = 29;
def A_IMULQ: i32 = 30;
def A_IDIVQ: i32 = 31;
def A_DIVQ: i32 = 32;
def A_NEGQ: i32 = 33;
def A_NOTQ: i32 = 34;
def A_ANDQ: i32 = 35;
def A_ORQ: i32 = 36;
def A_XORQ: i32 = 37;
def A_SHLQ: i32 = 38;
def A_SHRQ: i32 = 39;
def A_CMPQ: i32 = 40;
def A_PUSHQ: i32 = 41;
def A_POPQ: i32 = 42;
def A_LEAQ: i32 = 43;
def A_CALL: i32 = 44;
def A_RET: i32 = 45;
def A_JMP: i32 = 46;
def A_JE: i32 = 47;
def A_JNE: i32 = 48;
def A_JL: i32 = 49;
def A_JLE: i32 = 50;
def A_JG: i32 = 51;
def A_JGE: i32 = 52;
def A_JB: i32 = 53;
def A_JBE: i32 = 54;
def A_JA: i32 = 55;
def A_JAE: i32 = 56;
def A_JZ: i32 = 57;
def A_JNZ: i32 = 58;
def A_SYSCALL: i32 = 59;
// Writable data + reloc-only data. Mirror cmd/w6c/6.out.h.
// A_DATAW: bytes land in .data (RW) instead of .text.
// A_DATAR: record an R_X86_64_64 reloc at a .data slot, patched
// to a target symbol's runtime VA at link time.
def A_DATAW: i32 = 60;
def A_DATAR: i32 = 61;
// ---- structs (mirror cmd/w6a/a.h) --------------------------------------
type aoperand = struct {
atype: i32, // D_NONE / D_AX..D_R15 / D_CONST / D_INDIR / D_EXTERN / D_BRANCH
reg: i32,
offset: i64,
asym: str,
};
// `from` and `to` are pointer-to-aoperand (rather than embedded).
// The C cgen doesn't support chained-dot through embedded value
// fields, so allocating each operand once per prog lets us write
// `p.to.atype` directly.
type aprog = struct {
as_: i32,
from: *aoperand,
to: *aoperand,
line: i32,
label: str,
link: *aprog,
bytes: *u8, // payload for A_DATA
nbytes: u64,
};
type asym = struct {
name: str,
defined: i32,
istext: i32,
isdata: i32, // mutually exclusive with istext; DATAW symbols
isglobal: i32,
addr: u64, // offset within its section (.text or .data)
idx: i32,
snext: *asym,
};
type areloc = struct {
off: u64,
section: i32, // 0 = .text, 1 = .data
kind: i32,
asy: *asym,
addend: i64,
rnext: *areloc,
};
type afixup = struct {
off: u64, // where the rel32 lands in .text
label: str,
fnext: *afixup,
};
type asm_ = struct {
a: *arena,
file: str,
src: *u8,
srclen: u64,
pos: u64,
line: i32,
head: *aprog,
tail: *aprog,
text: *u8,
textcap: u64,
textlen: u64,
// Writable .data. Empty unless any DATAW directive was seen;
// obj.ww emits the extra section conditionally so .o output
// stays byte-identical for inputs that don't use DATAW (test
// 991 byte-diff invariant).
data: *u8,
datacap: u64,
datalen: u64,
syms: *asym,
relocs: *areloc,
fixups: *afixup,
errs: i32,
};
// MODULE: w6a
// selfhost/cmd/w6a/lex.ww — port of cmd/w6a/lex.c.
//
// Character-level helpers for w6a's line-oriented parser. The parser
// itself is in parse.ww; here we keep tokenisers for identifiers and
// numbers so parse.ww stays focused on syntax.
export fn isidstart(c: i32) bool = {
if (c == 95) { return true; };
if (c >= 65) { if (c <= 90) { return true; }; }; // A-Z
if (c >= 97) { if (c <= 122) { return true; }; }; // a-z
return false;
};
export fn isidcont(c: i32) bool = {
if (isidstart(c)) { return true; };
if (c >= 48) { if (c <= 57) { return true; }; }; // 0-9
if (c == 46) { return true; }; // .
return false;
};
// parsenum — read a leading [+-]?[0x|0X|0]?digits from p[0..n-1].
// Returns (value, consumed). Stops at first non-digit.
// Plain Plan 9-style: $123 / $0x1f / $-7. Decimal default; 0x prefix
// for hex; 0 prefix for octal when followed by a digit (else just 0).
export fn parsenum(p: *u8, n: u64) (i64, u64) = {
let i: u64 = 0u64;
let neg: bool = false;
if (i < n) {
if (p[i] == 45u8) { neg = true; i += 1u64; }
else { if (p[i] == 43u8) { i += 1u64; }; };
};
let base: i64 = 10i64;
if (i + 1u64 < n) {
if (p[i] == 48u8) {
if (p[i + 1u64] == 120u8) { base = 16i64; i += 2u64; }
else { if (p[i + 1u64] == 88u8) { base = 16i64; i += 2u64; }
else { if (p[i + 1u64] >= 48u8) { if (p[i + 1u64] <= 55u8) {
base = 8i64; i += 1u64;
};};};};
};
};
let v: i64 = 0i64;
let scan: bool = true;
for (scan) {
if (i >= n) { scan = false; }
else {
let c: u8 = p[i];
let d: i64 = -1i64;
if (c >= 48u8) { if (c <= 57u8) { d = (c - 48u8): i64; }; };
if (d < 0i64) {
if (base == 16i64) {
if (c >= 97u8) { if (c <= 102u8) { d = (c - 97u8): i64 + 10i64; }; };
if (c >= 65u8) { if (c <= 70u8) { d = (c - 65u8): i64 + 10i64; }; };
};
};
if (d < 0i64) { scan = false; }
else { if (d >= base) { scan = false; }
else {
v = v * base + d;
i += 1u64;
}; };
};
};
if (neg) { v = -v; };
return v, i;
};
// MODULE: w6a
// selfhost/cmd/w6a/parse.ww — port of cmd/w6a/parse.c.
//
// Line-oriented parser for the asm subset emitted by w6c.
// Grammar:
// line := blank | comment | label | text | instr
// blank := /^\s*$/
// comment := /^\s*\/\/.*$/
// label := /^IDENT:$/
// text := TEXT name,$framesize
// instr := \tMNEM\t[OP1[, OP2]]
// OP := $NUM | REG | NUM(REG) | (REG) | name(SB) | label
use os;
use mem;
use lex;
use types;
fn streqlit(p: *u8, n: u64, lit: str) bool = {
if (n != lit.len: u64) { return false; };
let i: u64 = 0u64;
for (i < n) {
let li: i32 = i: i32;
if (p[i] != lit[li]) { return false; };
i += 1u64;
};
return true;
};
// opcodelookup — name (length-bounded *u8) → A_*. Returns 0 (A_NOP)
// if not found.
fn opcodelookup(p: *u8, n: u64) i32 = {
if (streqlit(p, n, "MOVQ")) { return A_MOVQ; };
if (streqlit(p, n, "MOVL")) { return A_MOVL; };
if (streqlit(p, n, "MOVW")) { return A_MOVW; };
if (streqlit(p, n, "MOVB")) { return A_MOVB; };
if (streqlit(p, n, "MOVZBQ")) { return A_MOVZBQ; };
if (streqlit(p, n, "MOVZWQ")) { return A_MOVZWQ; };
if (streqlit(p, n, "MOVSXD")) { return A_MOVSXD; };
if (streqlit(p, n, "MOVSWQ")) { return A_MOVSWQ; };
if (streqlit(p, n, "MOVSBQ")) { return A_MOVSBQ; };
if (streqlit(p, n, "MOVSD")) { return A_MOVSD; };
if (streqlit(p, n, "ADDSD")) { return A_ADDSD; };
if (streqlit(p, n, "SUBSD")) { return A_SUBSD; };
if (streqlit(p, n, "MULSD")) { return A_MULSD; };
if (streqlit(p, n, "DIVSD")) { return A_DIVSD; };
if (streqlit(p, n, "UCOMISD")) { return A_UCOMISD; };
if (streqlit(p, n, "CVTTSD2SI")) { return A_CVTTSD2SI; };
if (streqlit(p, n, "CVTSI2SD")) { return A_CVTSI2SD; };
if (streqlit(p, n, "MOVSS")) { return A_MOVSS; };
if (streqlit(p, n, "ADDSS")) { return A_ADDSS; };
if (streqlit(p, n, "SUBSS")) { return A_SUBSS; };
if (streqlit(p, n, "MULSS")) { return A_MULSS; };
if (streqlit(p, n, "DIVSS")) { return A_DIVSS; };
if (streqlit(p, n, "UCOMISS")) { return A_UCOMISS; };
if (streqlit(p, n, "CVTTSS2SI")) { return A_CVTTSS2SI; };
if (streqlit(p, n, "CVTSI2SS")) { return A_CVTSI2SS; };
if (streqlit(p, n, "CVTSD2SS")) { return A_CVTSD2SS; };
if (streqlit(p, n, "CVTSS2SD")) { return A_CVTSS2SD; };
if (streqlit(p, n, "ADDQ")) { return A_ADDQ; };
if (streqlit(p, n, "SUBQ")) { return A_SUBQ; };
if (streqlit(p, n, "IMULQ")) { return A_IMULQ; };
if (streqlit(p, n, "IDIVQ")) { return A_IDIVQ; };
if (streqlit(p, n, "DIVQ")) { return A_DIVQ; };
if (streqlit(p, n, "NEGQ")) { return A_NEGQ; };
if (streqlit(p, n, "NOTQ")) { return A_NOTQ; };
if (streqlit(p, n, "ANDQ")) { return A_ANDQ; };
if (streqlit(p, n, "ORQ")) { return A_ORQ; };
if (streqlit(p, n, "XORQ")) { return A_XORQ; };
if (streqlit(p, n, "SHLQ")) { return A_SHLQ; };
if (streqlit(p, n, "SHRQ")) { return A_SHRQ; };
if (streqlit(p, n, "CMPQ")) { return A_CMPQ; };
if (streqlit(p, n, "PUSHQ")) { return A_PUSHQ; };
if (streqlit(p, n, "POPQ")) { return A_POPQ; };
if (streqlit(p, n, "LEAQ")) { return A_LEAQ; };
if (streqlit(p, n, "CALL")) { return A_CALL; };
if (streqlit(p, n, "RET")) { return A_RET; };
if (streqlit(p, n, "JMP")) { return A_JMP; };
if (streqlit(p, n, "JE")) { return A_JE; };
if (streqlit(p, n, "JNE")) { return A_JNE; };
if (streqlit(p, n, "JL")) { return A_JL; };
if (streqlit(p, n, "JLE")) { return A_JLE; };
if (streqlit(p, n, "JG")) { return A_JG; };
if (streqlit(p, n, "JGE")) { return A_JGE; };
if (streqlit(p, n, "JB")) { return A_JB; };
if (streqlit(p, n, "JBE")) { return A_JBE; };
if (streqlit(p, n, "JA")) { return A_JA; };
if (streqlit(p, n, "JAE")) { return A_JAE; };
if (streqlit(p, n, "JZ")) { return A_JZ; };
if (streqlit(p, n, "JNZ")) { return A_JNZ; };
if (streqlit(p, n, "SYSCALL")) { return A_SYSCALL; };
if (streqlit(p, n, "TEXT")) { return A_TEXT; };
if (streqlit(p, n, "DATA")) { return A_DATA; };
if (streqlit(p, n, "DATAW")) { return A_DATAW; };
if (streqlit(p, n, "DATAR")) { return A_DATAR; };
return A_NOP;
};
// reglookup — name → D_*. Returns D_NONE if not found.
fn reglookup(p: *u8, n: u64) i32 = {
if (streqlit(p, n, "AX")) { return D_AX; };
if (streqlit(p, n, "BX")) { return D_BX; };
if (streqlit(p, n, "CX")) { return D_CX; };
if (streqlit(p, n, "DX")) { return D_DX; };
if (streqlit(p, n, "SP")) { return D_SP; };
if (streqlit(p, n, "BP")) { return D_BP; };
if (streqlit(p, n, "SI")) { return D_SI; };
if (streqlit(p, n, "DI")) { return D_DI; };
if (streqlit(p, n, "R8")) { return D_R8; };
if (streqlit(p, n, "R9")) { return D_R9; };
if (streqlit(p, n, "R10")) { return D_R10; };
if (streqlit(p, n, "R11")) { return D_R11; };
if (streqlit(p, n, "R12")) { return D_R12; };
if (streqlit(p, n, "R13")) { return D_R13; };
if (streqlit(p, n, "R14")) { return D_R14; };
if (streqlit(p, n, "R15")) { return D_R15; };
if (streqlit(p, n, "X0")) { return D_X0; };
if (streqlit(p, n, "X1")) { return D_X1; };
if (streqlit(p, n, "X2")) { return D_X2; };
if (streqlit(p, n, "X3")) { return D_X3; };
if (streqlit(p, n, "X4")) { return D_X4; };
if (streqlit(p, n, "X5")) { return D_X5; };
if (streqlit(p, n, "X6")) { return D_X6; };
if (streqlit(p, n, "X7")) { return D_X7; };
if (streqlit(p, n, "X8")) { return D_X8; };
if (streqlit(p, n, "X9")) { return D_X9; };
if (streqlit(p, n, "X10")) { return D_X10; };
if (streqlit(p, n, "X11")) { return D_X11; };
if (streqlit(p, n, "X12")) { return D_X12; };
if (streqlit(p, n, "X13")) { return D_X13; };
if (streqlit(p, n, "X14")) { return D_X14; };
if (streqlit(p, n, "X15")) { return D_X15; };
if (streqlit(p, n, "SB")) { return D_PSB; };
if (streqlit(p, n, "FP")) { return D_PFP; };
return D_NONE;
};
export fn init(a: *asm_, ar: *arena, file: str, src: *u8, len: u64) void = {
a.a = ar;
a.file = file;
a.src = src;
a.srclen = len;
a.pos = 0u64;
a.line = 1;
a.head = nil;
a.tail = nil;
a.text = nil;
a.textcap = 0u64;
a.textlen = 0u64;
a.syms = nil;
a.relocs = nil;
a.fixups = nil;
a.errs = 0;
};
// `streq(str,str)` lives in asm.ww — same bundle, single definition.
export fn intern(a: *asm_, name: str) *asym = {
let s: *asym = a.syms;
for (s != nil) {
if (streq(s.name, name)) { return s; };
s = s.snext;
};
let n: *asym = amalloc(a.a, 64u64): *asym;
n.name = name;
n.snext = a.syms;
a.syms = n;
return n;
};
fn perr(a: *asm_, msg: str) void = {
os.write(2, "w6a: ".ptr, 4u64);
let f: str = a.file;
os.write(2, f.ptr, f.len: u64);
os.write(2, ": ".ptr, 2u64);
os.write(2, msg.ptr, msg.len: u64);
os.write(2, "\n".ptr, 1u64);
a.errs += 1;
};
// dupstr — copy n bytes from p into a fresh heap str.
fn dupstr(a: *arena, p: *u8, n: u64) str = {
return astrndup(a, p, n);
};
// ---- line iteration & whitespace --------------------------------------
// Read next line into a fresh heap buffer; returns (ptr, len) or (nil,0)
// at EOF. Advances a.pos past the newline.
fn nextline(a: *asm_) (*u8, u64) = {
if (a.pos >= a.srclen) { return nil, 0u64; };
let start: u64 = a.pos;
for (a.pos < a.srclen) {
if (a.src[a.pos] == 10u8) { a.pos = a.pos; a.pos += 0u64; } // no-op; explicit break via condition
else { a.pos += 1u64; continue; };
// hit newline
let n: u64 = a.pos - start;
let buf: *u8 = amalloc(a.a, n + 1u64): *u8;
let i: u64 = 0u64;
for (i < n) { buf[i] = a.src[start + i]; i += 1u64; };
buf[n] = 0u8;
a.pos += 1u64; // skip newline
return buf, n;
};
// EOF without trailing newline
let n: u64 = a.pos - start;
if (n == 0u64) { return nil, 0u64; };
let buf: *u8 = amalloc(a.a, n + 1u64): *u8;
let i: u64 = 0u64;
for (i < n) { buf[i] = a.src[start + i]; i += 1u64; };
buf[n] = 0u8;
return buf, n;
};
fn skipws(p: *u8, off: u64, n: u64) u64 = {
let i: u64 = off;
for (i < n) {
if (p[i] != 32u8) { if (p[i] != 9u8) { return i; }; };
i += 1u64;
};
return i;
};
// parseoperand — parse one operand from p[off..n), populate out.
// Returns new offset (clamped to n on error).
fn parseoperand(a: *asm_, p: *u8, offin: u64, n: u64, out: *aoperand) u64 = {
let off: u64 = skipws(p, offin, n);
out.atype = D_NONE;
out.reg = 0;
out.offset = 0i64;
let empty: str;
empty.ptr = nil; empty.len = 0;
out.asym = empty;
if (off >= n) { return off; };
let c0: u8 = p[off];
// $NUM
if (c0 == 36u8) { // '$'
off += 1u64;
let v: i64;
let used: u64;
v, used = parsenum(p + off, n - off);
out.atype = D_CONST;
out.offset = v;
return off + used;
};
// (REG)
if (c0 == 40u8) { // '('
off += 1u64;
let rstart: u64 = off;
for (off < n) {
if (p[off] == 41u8) { off = off; off += 0u64; } // no-op marker
else { off += 1u64; continue; };
let rn: u64 = off - rstart;
let r: i32 = reglookup(p + rstart, rn);
if (r == 0) { perr(a, "bad register in indirect"); return n; };
out.atype = D_INDIR;
out.reg = r;
out.offset = 0i64;
return off + 1u64; // past ')'
};
perr(a, "missing ')' in indirect");
return n;
};
// number(REG) — possibly signed — or bare $NUM-less constant
let cur: u64 = off;
let isnum: bool = false;
if (cur < n) {
if (p[cur] == 45u8) { isnum = true; }
else { if (p[cur] >= 48u8) { if (p[cur] <= 57u8) { isnum = true; }; }; };
};
if (isnum) {
let v: i64;
let used: u64;
v, used = parsenum(p + off, n - off);
let after: u64 = off + used;
if (after < n) { if (p[after] == 40u8) { // '('
let rstart: u64 = after + 1u64;
let cur2: u64 = rstart;
for (cur2 < n) {
if (p[cur2] == 41u8) { cur2 = cur2; cur2 += 0u64; }
else { cur2 += 1u64; continue; };
let rn: u64 = cur2 - rstart;
let r: i32 = reglookup(p + rstart, rn);
if (r == 0) { perr(a, "bad register"); return n; };
out.atype = D_INDIR;
out.reg = r;
out.offset = v;
return cur2 + 1u64;
};
perr(a, "missing ')'");
return n;
};};
out.atype = D_CONST;
out.offset = v;
return after;
};
// IDENT — register, symbol(SB), symbol+disp(SB), or branch label
if (isidstart(c0: i32)) {
let istart: u64 = off;
for (off < n) {
if (isidcont(p[off]: i32)) { off += 1u64; continue; };
off = off; off += 0u64; // loop break
let in_: u64 = off - istart;
// Optional `+disp` between the ident and `(SB)`. Used
// by DATAR to address bytes within a previously-defined
// .data slot (e.g. `DATAR s+8(SB),...`).
let symdisp: i64 = 0i64;
if (off < n) { if (p[off] == 43u8) { // '+'
off += 1u64;
let v: i64;
let used: u64;
v, used = parsenum(p + off, n - off);
symdisp = v;
off += used;
};};
// IDENT(SB) — external
if (off < n) { if (p[off] == 40u8) { // '('
let rstart: u64 = off + 1u64;
let cur2: u64 = rstart;
for (cur2 < n) {
if (p[cur2] == 41u8) { cur2 = cur2; cur2 += 0u64; }
else { cur2 += 1u64; continue; };
let rn: u64 = cur2 - rstart;
let r: i32 = reglookup(p + rstart, rn);
if (r == D_PSB) {
out.atype = D_EXTERN;
out.asym = dupstr(a.a, p + istart, in_);
out.offset = symdisp;
} else {
out.atype = D_INDIR;
out.reg = r;
out.offset = 0i64;
};
return cur2 + 1u64;
};
perr(a, "missing ')'");
return n;
};};
let r: i32 = reglookup(p + istart, in_);
if (r != D_NONE) {
out.atype = r;
return off;
};
out.atype = D_BRANCH;
out.asym = dupstr(a.a, p + istart, in_);
return off;
};
// EOF inside ident
let in_: u64 = off - istart;
let r: i32 = reglookup(p + istart, in_);
if (r != D_NONE) { out.atype = r; return off; };
out.atype = D_BRANCH;
out.asym = dupstr(a.a, p + istart, in_);
return off;
};
perr(a, "unrecognised operand");
return n;
};
// Append a fresh aprog to the list with given opcode and label.
fn addprog(a: *asm_, opc: i32, lbl: str) *aprog = {
let pr: *aprog = amalloc(a.a, 96u64): *aprog;
pr.as_ = opc;
pr.line = a.line;
pr.label = lbl;
pr.link = nil;
pr.bytes = nil;
pr.nbytes = 0u64;
pr.from = amalloc(a.a, 48u64): *aoperand;
pr.to = amalloc(a.a, 48u64): *aoperand;
if (a.head == nil) { a.head = pr; }
else { a.tail.link = pr; };
a.tail = pr;
return pr;
};
export fn parse(a: *asm_) i32 = {
let pending: str;
pending.ptr = nil; pending.len = 0;
for (true) {
let line: *u8;
let n: u64;
line, n = nextline(a);
if (line == nil) { return a.errs; };
// skip leading ws
let i: u64 = skipws(line, 0u64, n);
// blank or //-comment
if (i >= n) { a.line += 1; continue; };
if (i + 1u64 < n) {
if (line[i] == 47u8) { if (line[i + 1u64] == 47u8) {
a.line += 1; continue;
};};
};
// Label? IDENT: starting at column 0 (no leading tab).
// Only if the identifier is followed by ':'. Otherwise, fall
// through to mnemonic parsing so e.g. `TEXT foo,$0` (which
// also starts with an idchar in column 0) gets parsed.
if (line[0u64] != 9u8) {
if (isidstart(line[i]: i32)) {
let q: u64 = i;
let scanid: bool = true;
for (scanid) {
if (q >= n) { scanid = false; }
else { if (isidcont(line[q]: i32)) { q += 1u64; }
else { scanid = false; }; };
};
if (q < n) { if (line[q] == 58u8) { // ':'
let nm: str = dupstr(a.a, line + i, q - i);
// Pending label gets a NOP prog so addresses pin.
if (pending.len > 0) {
let np: *aprog = addprog(a, A_NOP, pending);
};
pending = nm;
a.line += 1;
continue;
};};
// not a label — fall through to mnemonic parse
};
};
// MNEMONIC at the start of the rest. Scan to first ws/EOL.
let mstart: u64 = i;
let m: u64 = mstart;
let scan: bool = true;
for (scan) {
if (m >= n) { scan = false; }
else { if (line[m] == 32u8) { scan = false; }
else { if (line[m] == 9u8) { scan = false; }
else { m += 1u64; }; }; };
};
let mlen: u64 = m - mstart;
let opc: i32 = opcodelookup(line + mstart, mlen);
if (opc == 0) {
if (mlen > 0u64) {
perr(a, "unknown opcode");
};
pending.ptr = nil; pending.len = 0;
a.line += 1; continue;
};
let pr: *aprog = addprog(a, opc, pending);
pending.ptr = nil; pending.len = 0;
// Skip ws after mnemonic
let r0: u64 = skipws(line, m, n);
if (opc == A_TEXT) {
// TEXT name,$framesize — find first ',' as the end of name.
let q: u64 = r0;
let commapos: u64 = n;
let scant: bool = true;
for (scant) {
if (q >= n) { scant = false; }
else { if (line[q] == 44u8) { commapos = q; scant = false; }
else { q += 1u64; }; };
};
let toop: *aoperand = pr.to;
toop.atype = D_EXTERN;
toop.asym = dupstr(a.a, line + r0, commapos - r0);
if (commapos < n) {
let p2: u64 = commapos + 1u64;
p2 = skipws(line, p2, n);
if (p2 < n) { if (line[p2] == 36u8) { p2 += 1u64; }; };
let v: i64;
let used: u64;
v, used = parsenum(line + p2, n - p2);
let fromop: *aoperand = pr.from;
fromop.atype = D_CONST;
fromop.offset = v;
};
a.line += 1; continue;
};
if (opc == A_DATA || opc == A_DATAW) {
// DATA / DATAW name(SB),"escaped bytes" — same syntax,
// different destination section (.text vs .data).
let q: u64 = r0;
let lparen: u64 = n;
let scand: bool = true;
for (scand) {
if (q >= n) { scand = false; }
else { if (line[q] == 40u8) { lparen = q; scand = false; }
else { q += 1u64; }; };
};
let toop: *aoperand = pr.to;
toop.atype = D_EXTERN;
toop.asym = dupstr(a.a, line + r0, lparen - r0);
// Skip past `(SB)` to land just after ')'.
let p2: u64 = lparen;
let scand2: bool = true;
for (scand2) {
if (p2 >= n) { scand2 = false; }
else { if (line[p2] == 41u8) { p2 += 1u64; scand2 = false; }
else { p2 += 1u64; }; };
};
// Skip ws / ',' / tab between `)` and the `"`.
let scand3: bool = true;
for (scand3) {
if (p2 >= n) { scand3 = false; }
else { if (line[p2] == 32u8) { p2 += 1u64; }
else { if (line[p2] == 44u8) { p2 += 1u64; }
else { if (line[p2] == 9u8) { p2 += 1u64; }
else { scand3 = false; }; }; }; };
};
if (p2 >= n) { perr(a, "DATA missing payload"); a.line += 1; continue; };
if (line[p2] != 34u8) { perr(a, "DATA expects \"...\""); a.line += 1; continue; };
p2 += 1u64; // past opening "
// Parse escape sequence into a fresh growable buffer.
let cap: u64 = 32u64;
let blen: u64 = 0u64;
let dbuf: *u8 = amalloc(a.a, cap): *u8;
for (p2 < n) {
if (line[p2] == 34u8) { p2 = p2; p2 += 0u64; p2 = n + 1u64; }
else {
let ch: u8 = line[p2];
p2 += 1u64;
if (ch == 92u8) { // '\'
if (p2 < n) {
let e: u8 = line[p2];
p2 += 1u64;
if (e == 110u8) { ch = 10u8; } // 'n'
else { if (e == 116u8) { ch = 9u8; }
else { if (e == 114u8) { ch = 13u8; }
else { if (e == 92u8) { ch = 92u8; }
else { if (e == 34u8) { ch = 34u8; }
else { if (e == 48u8) { ch = 0u8; }
else { if (e == 120u8) { // 'x'
if (p2 + 1u64 < n) {
let hi: u8 = line[p2];
let lo: u8 = line[p2 + 1u64];
p2 += 2u64;
let h: u8 = 0u8;
let l: u8 = 0u8;
if (hi <= 57u8) { h = hi - 48u8; }
else { h = (hi | 32u8) - 97u8 + 10u8; };
if (lo <= 57u8) { l = lo - 48u8; }
else { l = (lo | 32u8) - 97u8 + 10u8; };
ch = (h << 4u8) | l;
};
}
else { ch = e; };};};};};};};
};
};
if (blen + 1u64 > cap) {
let ncap: u64 = cap * 2u64;
let nb: *u8 = amalloc(a.a, ncap): *u8;
let bi: u64 = 0u64;
for (bi < blen) { nb[bi] = dbuf[bi]; bi += 1u64; };
dbuf = nb;
cap = ncap;
};
dbuf[blen] = ch;
blen += 1u64;
};
};
pr.bytes = dbuf;
pr.nbytes = blen;
a.line += 1; continue;
};
// Generic instruction: 0/1/2 operands separated by ','.
// Find top-level comma.
let comma: i64 = -1i64;
let q: u64 = r0;
for (q < n) {
if (line[q] == 44u8) {
if (comma < 0i64) { comma = q: i64; };
};
q += 1u64;
};
if (comma >= 0i64) {
let cu: u64 = comma: u64;
parseoperand(a, line, r0, cu, pr.from);
parseoperand(a, line + (cu + 1u64), 0u64, n - (cu + 1u64), pr.to);
} else { if (r0 < n) {
parseoperand(a, line, r0, n, pr.to);
};};
a.line += 1;
};
return a.errs;
};
// MODULE: w6a
// selfhost/cmd/w6a/asm.ww — port of cmd/w6a/asm.c.
//
// Encode the parsed aprog list into amd64 machine bytes, appending to
// asm_.text. Relocations for CALL/branch targets that resolve to
// externals are queued in asm_.relocs.
//
// Encoding subset matches what w6c emits — see cmd/w6a/asm.c for the
// authoritative list. Helpers (rcode/rhi/modrm/emitrex etc.) are
// fully ported; encode itself is still a stub pending the full
// switch over A_*.
use os;
use mem;
use types;
// ---- text buffer growth ------------------------------------------------
export fn emitbyte(a: *asm_, b: u8) void = {
if (a.textlen + 1u64 > a.textcap) {
let nc: u64 = a.textcap;
if (nc == 0u64) { nc = 4096u64; };
nc = nc * 2u64;
let nb: *u8 = os.alloc(nc): *u8;
let i: u64 = 0u64;
for (i < a.textlen) { nb[i] = a.text[i]; i += 1u64; };
a.text = nb;
a.textcap = nc;
};
a.text[a.textlen] = b;
a.textlen += 1u64;
};
export fn emitu32(a: *asm_, v: u32) void = {
emitbyte(a, (v & 255u32): u8);
emitbyte(a, ((v >> 8u32) & 255u32): u8);
emitbyte(a, ((v >> 16u32) & 255u32): u8);
emitbyte(a, ((v >> 24u32) & 255u32): u8);
};
export fn addreloc(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
let r: *areloc = amalloc(a.a, 64u64): *areloc;
r.off = off;
r.section = 0; // .text
r.kind = kind;
r.asy = s;
r.addend = add;
r.rnext = a.relocs;
a.relocs = r;
};
// Record a relocation that lives in the .data section. Used by
// DATAR to patch a 64-bit slot with a symbol's runtime VA. obj.ww
// separates these into .rela.data when emitting the .o.
export fn addrelocdata(a: *asm_, off: u64, kind: i32, s: *asym, add: i64) void = {
let r: *areloc = amalloc(a.a, 64u64): *areloc;
r.off = off;
r.section = 1; // .data
r.kind = kind;
r.asy = s;
r.addend = add;
r.rnext = a.relocs;
a.relocs = r;
};
// Append one byte to the writable .data buffer. Mirrors emitbyte
// but targets a.data instead of a.text.
export fn emitdatabyte(a: *asm_, b: u8) void = {
if (a.datalen + 1u64 > a.datacap) {
let nc: u64 = a.datacap;
if (nc == 0u64) { nc = 256u64; };
nc = nc * 2u64;
let nb: *u8 = os.alloc(nc): *u8;
let i: u64 = 0u64;
for (i < a.datalen) { nb[i] = a.data[i]; i += 1u64; };
a.data = nb;
a.datacap = nc;
};
a.data[a.datalen] = b;
a.datalen += 1u64;
};
// ---- register codes ----------------------------------------------------
// Low 3 bits of register encoding.
fn rcode(r: i32) i32 = {
if (r == D_AX) { return 0; }; if (r == D_CX) { return 1; };
if (r == D_DX) { return 2; }; if (r == D_BX) { return 3; };
if (r == D_SP) { return 4; }; if (r == D_BP) { return 5; };
if (r == D_SI) { return 6; }; if (r == D_DI) { return 7; };
if (r == D_R8) { return 0; }; if (r == D_R9) { return 1; };
if (r == D_R10) { return 2; }; if (r == D_R11) { return 3; };
if (r == D_R12) { return 4; }; if (r == D_R13) { return 5; };
if (r == D_R14) { return 6; }; if (r == D_R15) { return 7; };
if (r == D_X0) { return 0; }; if (r == D_X1) { return 1; };
if (r == D_X2) { return 2; }; if (r == D_X3) { return 3; };
if (r == D_X4) { return 4; }; if (r == D_X5) { return 5; };
if (r == D_X6) { return 6; }; if (r == D_X7) { return 7; };
if (r == D_X8) { return 0; }; if (r == D_X9) { return 1; };
if (r == D_X10) { return 2; }; if (r == D_X11) { return 3; };
if (r == D_X12) { return 4; }; if (r == D_X13) { return 5; };
if (r == D_X14) { return 6; }; if (r == D_X15) { return 7; };
return 0;
};
// 1 if r needs the REX high bit (R8..R15 or X8..X15).
fn rhi(r: i32) i32 = {
if (r >= D_R8) { if (r <= D_R15) { return 1; }; };
if (r >= D_X8) { if (r <= D_X15) { return 1; }; };
return 0;
};
fn isxmm(r: i32) bool = {
if (r >= D_X0) { if (r <= D_X15) { return true; }; };
return false;
};
// ModR/M byte builder.
fn modrmbyte(mod: i32, reg: i32, rm: i32) u8 = {
return (((mod & 3) << 6) | ((reg & 7) << 3) | (rm & 7)): u8;
};
// REX prefix; W=1 for 64-bit operand size.
fn emitrex(a: *asm_, regbit: i32, rmbit: i32, w: i32) void = {
let b: u8 = 64u8; // 0x40
if (w != 0) { b = b | 8u8; };
if (regbit != 0) { b = b | 4u8; };
if (rmbit != 0) { b = b | 1u8; };
if (b != 64u8) { emitbyte(a, b); }
else { if (w != 0) { emitbyte(a, b); }; };
};
// ModR/M + (optional) SIB + displacement for [base+disp].
// Special-cases SP (needs SIB) and BP (forces explicit disp).
fn emitmodrmmem(a: *asm_, regfield: i32, base: i32, disp: i64) void = {
let rm: i32 = rcode(base);
let needsib: bool = (rm == 4);
let forceddisp: bool = false;
if (rm == 5) { if (disp == 0i64) { forceddisp = true; }; };
let mod: i32 = 2;
if (disp == 0i64) {
if (!forceddisp) { mod = 0; }
else { mod = 1; };
} else {
if (disp >= -128i64) { if (disp <= 127i64) { mod = 1; }; };
};
emitbyte(a, modrmbyte(mod, regfield, rm));
if (needsib) {
emitbyte(a, 36u8); // 0x24: scale=0 idx=4(none) base=4
};
if (mod == 1) {
emitbyte(a, (disp: u64 & 255u64): u8);
} else { if (mod == 2) {
emitu32(a, disp: u32);
};};
};
// reg→reg "src, dst" generic encoding (89 /r, 01 /r, etc.).
fn encoderr(a: *asm_, opcode: u8, src: i32, dst: i32) void = {
emitrex(a, rhi(src), rhi(dst), 1);
emitbyte(a, opcode);
emitbyte(a, modrmbyte(3, rcode(src), rcode(dst)));
};
// reg→mem(base, disp) (e.g. MOVQ src reg into mem; opcode = 0x89).
fn encoderm(a: *asm_, opcode: u8, srcreg: i32, base: i32, disp: i64) void = {
emitrex(a, rhi(srcreg), rhi(base), 1);
emitbyte(a, opcode);
emitmodrmmem(a, rcode(srcreg), base, disp);
};
// mem(base, disp) → reg (e.g. MOVQ mem into reg; opcode = 0x8B).
fn encodemr(a: *asm_, opcode: u8, dstreg: i32, base: i32, disp: i64) void = {
emitrex(a, rhi(dstreg), rhi(base), 1);
emitbyte(a, opcode);
emitmodrmmem(a, rcode(dstreg), base, disp);
};
// OPCODE /n imm32 reg form (e.g. ADDQ $imm, reg).
fn encoderiimm32(a: *asm_, opcode: u8, subop: i32, dst: i32, imm: i32) void = {
emitrex(a, 0, rhi(dst), 1);
emitbyte(a, opcode);
emitbyte(a, modrmbyte(3, subop, rcode(dst)));
emitu32(a, imm: u32);
};
// Unary on reg: F7 /n reg, etc.
fn encodeunary(a: *asm_, opcode: u8, subop: i32, dst: i32) void = {
emitrex(a, 0, rhi(dst), 1);
emitbyte(a, opcode);
emitbyte(a, modrmbyte(3, subop, rcode(dst)));
};
// SSE2 helpers. Plan 9 syntax: source first, destination second.
// For ADDSD-style ops we put dst in the reg field, src in r/m.
fn sserr(a: *asm_, prefix: u8, op2: u8, regop: i32, rmop: i32) void = {
if (prefix != 0u8) { emitbyte(a, prefix); };
emitrex(a, rhi(regop), rhi(rmop), 0);
emitbyte(a, 15u8); // 0x0F
emitbyte(a, op2);
emitbyte(a, modrmbyte(3, rcode(regop), rcode(rmop)));
};
fn ssemrload(a: *asm_, prefix: u8, op2: u8, regop: i32, base: i32, disp: i64) void = {
if (prefix != 0u8) { emitbyte(a, prefix); };
emitrex(a, rhi(regop), rhi(base), 0);
emitbyte(a, 15u8);
emitbyte(a, op2);
emitmodrmmem(a, rcode(regop), base, disp);
};
// REX.W variant of sse_rr (CVTTSD2SI / CVTSI2SD).
fn sserrw(a: *asm_, prefix: u8, op2: u8, regop: i32, rmop: i32) void = {
if (prefix != 0u8) { emitbyte(a, prefix); };
emitrex(a, rhi(regop), rhi(rmop), 1);
emitbyte(a, 15u8);
emitbyte(a, op2);
emitbyte(a, modrmbyte(3, rcode(regop), rcode(rmop)));
};
// ---- label resolution / fixups ----------------------------------------
fn streq(a: str, b: str) bool = {
if (a.len != b.len) { return false; };
let i: i32 = 0;
for (i < a.len) {
if (a[i] != b[i]) { return false; };
i += 1;
};
return true;
};
fn resolvelabel(a: *asm_, name: str) u64 = {
let s: *asym = a.syms;
for (s != nil) {
if (s.defined != 0) { if (streq(s.name, name)) { return s.addr; }; };
s = s.snext;
};
return 0u64;
};
fn labeldefined(a: *asm_, name: str) bool = {
let s: *asym = a.syms;
for (s != nil) {
if (s.defined != 0) { if (streq(s.name, name)) { return true; }; };
s = s.snext;
};
return false;
};
// ---- fixup helper -----------------------------------------------------
fn addfixup(a: *asm_, off: u64, label: str) void = {
let f: *afixup = amalloc(a.a, 48u64): *afixup;
f.off = off;
f.label = label;
f.fnext = a.fixups;
a.fixups = f;
};
fn isgpr(t: i32) bool = {
if (t >= D_AX) { if (t <= D_R15) { return true; }; };
return false;
};
// `intern` lives in parse.ww — flat-scope concat lets us call it
// directly without an @symbol declaration here.
// ---- encode ----------------------------------------------------------
export fn encode(a: *asm_) i32 = {
let p: *aprog = a.head;
for (p != nil) {
// Define any pending label at the current PC.
if (p.label.len > 0) {
let s: *asym = intern(a, p.label);
s.defined = 1;
s.istext = 1;
s.addr = a.textlen;
};
let op: i32 = p.as_;
if (op == A_NOP) {
p = p.link; continue;
};
if (op == A_TEXT) {
let s: *asym = intern(a, p.to.asym);
s.defined = 1;
s.istext = 1;
s.isglobal = 1;
s.addr = a.textlen;
p = p.link; continue;
};
if (op == A_DATA) {
let s: *asym = intern(a, p.to.asym);
s.defined = 1;
s.istext = 1;
s.isglobal = 1;
s.addr = a.textlen;
let i: u64 = 0u64;
for (i < p.nbytes) { emitbyte(a, p.bytes[i]); i += 1u64; };
p = p.link; continue;
};
if (op == A_DATAW) {
// Writable variant: bytes go into .data instead of
// .text. obj.ww emits the extra section conditionally
// on datalen > 0 so .o output stays byte-identical
// for inputs that don't use DATAW.
let s: *asym = intern(a, p.to.asym);
s.defined = 1;
s.isdata = 1;
s.isglobal = 1;
s.addr = a.datalen;
let i: u64 = 0u64;
for (i < p.nbytes) { emitdatabyte(a, p.bytes[i]); i += 1u64; };
p = p.link; continue;
};
if (op == A_DATAR) {
// DATAR slot+off(SB), target(SB) — record an
// R_X86_64_64 relocation at slot+off in .data
// pointing at target. Slot must already be defined
// by a prior DATAW.
let holder: *asym = intern(a, p.from.asym);
if (holder.defined == 0) {
p = p.link; continue;
};
if (holder.isdata == 0) {
p = p.link; continue;
};
let target: *asym = intern(a, p.to.asym);
let reloff: u64 = holder.addr + p.from.offset: u64;
addrelocdata(a, reloff, 1 /* R_X86_64_64 */,
target, 0i64);
p = p.link; continue;
};
if (op == A_RET) {
emitbyte(a, 195u8); // 0xC3
p = p.link; continue;
};
if (op == A_SYSCALL) {
emitbyte(a, 15u8);
emitbyte(a, 5u8);
p = p.link; continue;
};
if (op == A_PUSHQ) {
if (rhi(p.to.atype) != 0) { emitbyte(a, 65u8); }; // 0x41
emitbyte(a, (80 + rcode(p.to.atype)): u8); // 0x50
p = p.link; continue;
};
if (op == A_POPQ) {
if (rhi(p.to.atype) != 0) { emitbyte(a, 65u8); };
emitbyte(a, (88 + rcode(p.to.atype)): u8); // 0x58
p = p.link; continue;
};
if (op == A_NEGQ) { encodeunary(a, 247u8, 3, p.to.atype); p = p.link; continue; };
if (op == A_NOTQ) { encodeunary(a, 247u8, 2, p.to.atype); p = p.link; continue; };
if (op == A_IDIVQ) { encodeunary(a, 247u8, 7, p.to.atype); p = p.link; continue; };
if (op == A_DIVQ) { encodeunary(a, 247u8, 6, p.to.atype); p = p.link; continue; };
if (op == A_MOVQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
let v: i64 = p.from.offset;
if (v >= -2147483648i64) { if (v <= 2147483647i64) {
encoderiimm32(a, 199u8, 0, tt, v: i32);
p = p.link; continue;
};};
// movabs r64, imm64: REX.W B8+rd imm64
emitrex(a, 0, rhi(tt), 1);
emitbyte(a, (184 + rcode(tt)): u8);
let k: i32 = 0;
for (k < 8) {
emitbyte(a, ((v: u64 >> (k: u64 * 8u64)) & 255u64): u8);
k += 1;
};
p = p.link; continue;
};};
if (isgpr(ft)) { if (isgpr(tt)) {
encoderr(a, 137u8, ft, tt); // 0x89
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isgpr(tt)) {
encodemr(a, 139u8, tt, p.from.reg, p.from.offset); // 0x8B
p = p.link; continue;
};};
if (isgpr(ft)) { if (tt == D_INDIR) {
encoderm(a, 137u8, ft, p.to.reg, p.to.offset);
p = p.link; continue;
};};
if (ft == D_CONST) { if (tt == D_INDIR) {
emitrex(a, 0, rhi(p.to.reg), 1);
emitbyte(a, 199u8);
emitmodrmmem(a, 0, p.to.reg, p.to.offset);
emitu32(a, p.from.offset: u32);
p = p.link; continue;
};};
if (ft == D_EXTERN) { if (isgpr(tt)) {
// RIP-relative load: 48 8B /r mod=00 rm=5 disp32
emitrex(a, rhi(tt), 0, 1);
emitbyte(a, 139u8);
emitbyte(a, modrmbyte(0, rcode(tt), 5));
let reloff: u64 = a.textlen;
emitu32(a, 0u32);
let s: *asym = intern(a, p.from.asym);
addreloc(a, reloff, 2, s, -4i64);
p = p.link; continue;
};};
if (isgpr(ft)) { if (tt == D_EXTERN) {
// RIP-relative store: 48 89 /r mod=00 rm=5 disp32
emitrex(a, rhi(ft), 0, 1);
emitbyte(a, 137u8);
emitbyte(a, modrmbyte(0, rcode(ft), 5));
let reloff: u64 = a.textlen;
emitu32(a, 0u32);
let s: *asym = intern(a, p.to.asym);
addreloc(a, reloff, 2, s, -4i64);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVQ shape\n".ptr, 27u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVB) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (isgpr(ft)) { if (tt == D_INDIR) {
emitrex(a, rhi(ft), rhi(p.to.reg), 0);
emitbyte(a, 136u8); // 0x88
emitmodrmmem(a, rcode(ft), p.to.reg, p.to.offset);
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 0);
emitbyte(a, 138u8); // 0x8A
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVB shape\n".ptr, 27u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVW) {
// 16-bit MOV: 0x66 operand-size prefix + the 32-bit
// MOV opcodes 0x89 / 0x8B. No REX.W.
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (isgpr(ft)) { if (tt == D_INDIR) {
emitbyte(a, 102u8); // 0x66
emitrex(a, rhi(ft), rhi(p.to.reg), 0);
emitbyte(a, 137u8); // 0x89
emitmodrmmem(a, rcode(ft), p.to.reg, p.to.offset);
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isgpr(tt)) {
emitbyte(a, 102u8); // 0x66
emitrex(a, rhi(tt), rhi(p.from.reg), 0);
emitbyte(a, 139u8); // 0x8B
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVW shape\n".ptr, 27u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVZWQ) {
// MOVZX r64, r/m16 — 0F B7 /r with REX.W.
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 1);
emitbyte(a, 15u8);
emitbyte(a, 183u8); // 0xB7
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVZWQ shape\n".ptr, 29u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVSWQ) {
// MOVSX r64, r/m16 — 0F BF /r with REX.W.
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 1);
emitbyte(a, 15u8);
emitbyte(a, 191u8); // 0xBF
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
if (isgpr(ft)) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(ft), 1);
emitbyte(a, 15u8);
emitbyte(a, 191u8); // 0xBF
emitbyte(a, modrmbyte(3, rcode(tt), rcode(ft)));
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVSWQ shape\n".ptr, 29u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVSBQ) {
// MOVSX r64, r/m8 — 0F BE /r with REX.W.
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 1);
emitbyte(a, 15u8);
emitbyte(a, 190u8); // 0xBE
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
if (isgpr(ft)) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(ft), 1);
emitbyte(a, 15u8);
emitbyte(a, 190u8); // 0xBE
emitbyte(a, modrmbyte(3, rcode(tt), rcode(ft)));
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVSBQ shape\n".ptr, 29u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVZBQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 1);
emitbyte(a, 15u8);
emitbyte(a, 182u8); // 0xB6
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVZBQ shape\n".ptr, 29u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVL) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (isgpr(ft)) { if (tt == D_INDIR) {
emitrex(a, rhi(ft), rhi(p.to.reg), 0);
emitbyte(a, 137u8);
emitmodrmmem(a, rcode(ft), p.to.reg, p.to.offset);
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 0);
emitbyte(a, 139u8);
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
if (isgpr(ft)) { if (isgpr(tt)) {
emitrex(a, rhi(ft), rhi(tt), 0);
emitbyte(a, 137u8);
emitbyte(a, modrmbyte(3, rcode(ft), rcode(tt)));
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVL shape\n".ptr, 27u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVSXD) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_INDIR) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(p.from.reg), 1);
emitbyte(a, 99u8); // 0x63
emitmodrmmem(a, rcode(tt), p.from.reg, p.from.offset);
p = p.link; continue;
};};
if (isgpr(ft)) { if (isgpr(tt)) {
emitrex(a, rhi(tt), rhi(ft), 1);
emitbyte(a, 99u8); // 0x63
emitbyte(a, modrmbyte(3, rcode(tt), rcode(ft)));
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVSXD shape\n".ptr, 29u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_MOVSD) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (isxmm(ft)) { if (isxmm(tt)) {
sserr(a, 242u8, 16u8, tt, ft);
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isxmm(tt)) {
ssemrload(a, 242u8, 16u8, tt, p.from.reg, p.from.offset);
p = p.link; continue;
};};
if (isxmm(ft)) { if (tt == D_INDIR) {
ssemrload(a, 242u8, 17u8, ft, p.to.reg, p.to.offset);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVSD shape\n".ptr, 28u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_ADDSD) { sserr(a, 242u8, 88u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_SUBSD) { sserr(a, 242u8, 92u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_MULSD) { sserr(a, 242u8, 89u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_DIVSD) { sserr(a, 242u8, 94u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_UCOMISD) { sserr(a, 102u8, 46u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_CVTTSD2SI) { sserrw(a, 242u8, 44u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_CVTSI2SD) { sserrw(a, 242u8, 42u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_MOVSS) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (isxmm(ft)) { if (isxmm(tt)) {
sserr(a, 243u8, 16u8, tt, ft); p = p.link; continue;
};};
if (ft == D_INDIR) { if (isxmm(tt)) {
ssemrload(a, 243u8, 16u8, tt, p.from.reg, p.from.offset);
p = p.link; continue;
};};
if (isxmm(ft)) { if (tt == D_INDIR) {
ssemrload(a, 243u8, 17u8, ft, p.to.reg, p.to.offset);
p = p.link; continue;
};};
os.write(2, "w6a: unsupported MOVSS shape\n".ptr, 28u64);
a.errs += 1;
p = p.link; continue;
};
if (op == A_ADDSS) { sserr(a, 243u8, 88u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_SUBSS) { sserr(a, 243u8, 92u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_MULSS) { sserr(a, 243u8, 89u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_DIVSS) { sserr(a, 243u8, 94u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_UCOMISS) { sserr(a, 0u8, 46u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_CVTTSS2SI) { sserrw(a, 243u8, 44u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_CVTSI2SS) { sserrw(a, 243u8, 42u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_CVTSD2SS) { sserr(a, 242u8, 90u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_CVTSS2SD) { sserr(a, 243u8, 90u8, p.to.atype, p.from.atype); p = p.link; continue; };
if (op == A_ADDQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
encoderiimm32(a, 129u8, 0, tt, p.from.offset: i32); // 0x81
p = p.link; continue;
};};
if (ft == D_CONST) { if (tt == D_INDIR) {
emitrex(a, 0, rhi(p.to.reg), 1);
emitbyte(a, 129u8);
emitmodrmmem(a, 0, p.to.reg, p.to.offset);
emitu32(a, p.from.offset: u32);
p = p.link; continue;
};};
if (isgpr(ft)) { if (tt == D_INDIR) {
encoderm(a, 1u8, ft, p.to.reg, p.to.offset);
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isgpr(tt)) {
encodemr(a, 3u8, tt, p.from.reg, p.from.offset);
p = p.link; continue;
};};
encoderr(a, 1u8, ft, tt);
p = p.link; continue;
};
if (op == A_SUBQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
encoderiimm32(a, 129u8, 5, tt, p.from.offset: i32);
p = p.link; continue;
};};
if (ft == D_CONST) { if (tt == D_INDIR) {
emitrex(a, 0, rhi(p.to.reg), 1);
emitbyte(a, 129u8);
emitmodrmmem(a, 5, p.to.reg, p.to.offset);
emitu32(a, p.from.offset: u32);
p = p.link; continue;
};};
if (isgpr(ft)) { if (tt == D_INDIR) {
encoderm(a, 41u8, ft, p.to.reg, p.to.offset); // 0x29
p = p.link; continue;
};};
if (ft == D_INDIR) { if (isgpr(tt)) {
encodemr(a, 43u8, tt, p.from.reg, p.from.offset); // 0x2B
p = p.link; continue;
};};
encoderr(a, 41u8, ft, tt);
p = p.link; continue;
};
if (op == A_ANDQ) {
// AND r/m64, imm32 — 0x81 /4 (REX.W). Without the
// D_CONST path encoderr would silently emit 0x21
// with garbage reg fields.
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
encoderiimm32(a, 129u8, 4, tt, p.from.offset: i32);
p = p.link; continue;
};};
encoderr(a, 33u8, ft, tt); // 0x21
p = p.link; continue;
};
if (op == A_ORQ) {
// OR r/m64, imm32 — 0x81 /1 (REX.W). Mirrors ANDQ.
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
encoderiimm32(a, 129u8, 1, tt, p.from.offset: i32);
p = p.link; continue;
};};
encoderr(a, 9u8, ft, tt); // 0x09
p = p.link; continue;
};
if (op == A_XORQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
encoderiimm32(a, 129u8, 6, tt, p.from.offset: i32);
p = p.link; continue;
};};
encoderr(a, 49u8, ft, tt); // 0x31
p = p.link; continue;
};
if (op == A_IMULQ) {
emitrex(a, rhi(p.to.atype), rhi(p.from.atype), 1);
emitbyte(a, 15u8);
emitbyte(a, 175u8); // 0xAF
emitbyte(a, modrmbyte(3, rcode(p.to.atype), rcode(p.from.atype)));
p = p.link; continue;
};
if (op == A_SHLQ) { encodeunary(a, 211u8, 4, p.to.atype); p = p.link; continue; }; // 0xD3
if (op == A_SHRQ) { encodeunary(a, 211u8, 5, p.to.atype); p = p.link; continue; };
if (op == A_CMPQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_CONST) { if (isgpr(tt)) {
encoderiimm32(a, 129u8, 7, tt, p.from.offset: i32);
p = p.link; continue;
};};
encoderr(a, 57u8, ft, tt); // 0x39
p = p.link; continue;
};
if (op == A_LEAQ) {
let ft: i32 = p.from.atype;
let tt: i32 = p.to.atype;
if (ft == D_INDIR) { if (isgpr(tt)) {
encodemr(a, 141u8, tt, p.from.reg, p.from.offset); // 0x8D
p = p.link; continue;
};};
if (ft == D_EXTERN) { if (isgpr(tt)) {
emitrex(a, rhi(tt), 0, 1);
emitbyte(a, 141u8);
emitbyte(a, modrmbyte(0, rcode(tt), 5));
let reloff: u64 = a.textlen;
emitu32(a, 0u32);
let s: *asym = intern(a, p.from.asym);
addreloc(a, reloff, 2, s, -4i64);
p = p.link; continue;
};};
p = p.link; continue;
};
if (op == A_CALL) {
let tt: i32 = p.to.atype;
if (tt == D_EXTERN) {
emitbyte(a, 232u8); // 0xE8
let reloff: u64 = a.textlen;
emitu32(a, 0u32);
let s: *asym = intern(a, p.to.asym);
addreloc(a, reloff, 4, s, -4i64);
p = p.link; continue;
};
if (tt == D_BRANCH) {
emitbyte(a, 232u8);
addfixup(a, a.textlen, p.to.asym);
emitu32(a, 0u32);
p = p.link; continue;
};
if (isgpr(tt)) {
if (rhi(tt) != 0) { emitbyte(a, 65u8); };
emitbyte(a, 255u8); // 0xFF
emitbyte(a, modrmbyte(3, 2, rcode(tt)));
p = p.link; continue;
};
p = p.link; continue;
};
if (op == A_JMP) {
emitbyte(a, 233u8); // 0xE9
addfixup(a, a.textlen, p.to.asym);
emitu32(a, 0u32);
p = p.link; continue;
};
// Conditional jumps. 0x0F + cc + rel32.
let cc: u8 = 0u8;
let isjcc: bool = true;
if (op == A_JE) { cc = 132u8; } // 0x84
else { if (op == A_JZ) { cc = 132u8; }
else { if (op == A_JNE) { cc = 133u8; }
else { if (op == A_JNZ) { cc = 133u8; }
else { if (op == A_JL) { cc = 140u8; }
else { if (op == A_JLE) { cc = 142u8; }
else { if (op == A_JG) { cc = 143u8; }
else { if (op == A_JGE) { cc = 141u8; }
else { if (op == A_JB) { cc = 130u8; }
else { if (op == A_JBE) { cc = 134u8; }
else { if (op == A_JA) { cc = 135u8; }
else { if (op == A_JAE) { cc = 131u8; }
else { isjcc = false; };};};};};};};};};};};};
if (isjcc) {
emitbyte(a, 15u8);
emitbyte(a, cc);
addfixup(a, a.textlen, p.to.asym);
emitu32(a, 0u32);
p = p.link; continue;
};
os.write(2, "w6a: unsupported opcode\n".ptr, 23u64);
a.errs += 1;
p = p.link;
};
// Second pass: patch fixups (forward label refs).
let f: *afixup = a.fixups;
for (f != nil) {
if (!labeldefined(a, f.label)) {
os.write(2, "w6a: undefined label '".ptr, 21u64);
let lbl: str = f.label;
os.write(2, lbl.ptr, lbl.len: u64);
os.write(2, "'\n".ptr, 2u64);
a.errs += 1;
f = f.fnext;
continue;
};
let target: u64 = resolvelabel(a, f.label);
let rel: i64 = target: i64 - (f.off: i64 + 4i64);
let rel32: u32 = rel: u32;
a.text[f.off] = (rel32 & 255u32): u8;
a.text[f.off + 1u64] = ((rel32 >> 8u32) & 255u32): u8;
a.text[f.off + 2u64] = ((rel32 >> 16u32) & 255u32): u8;
a.text[f.off + 3u64] = ((rel32 >> 24u32) & 255u32): u8;
f = f.fnext;
};
return a.errs;
};
// MODULE: w6a
// selfhost/cmd/w6a/obj.ww — port of cmd/w6a/obj.c.
//
// Emit a tiny ELF64 relocatable object. Layout (in file order):
// [0] ELF header
// [1] Section .text (program bytes)
// [2] Section .rela.text (relocations)
// [3] Section .symtab
// [4] Section .strtab
// [5] Section .shstrtab
// [6] Section header table
//
// Symtab indices: 0 = STN_UNDEF, 1.. = our syms. Only GLOBAL symbols.
use os;
use mem;
use types;
// Local wrappers around os.writeall's tagged return — collapse the
// (i64 | oserror) back to a boolean / int sentinel for the
// length-checked / fire-and-forget write patterns below.
fn wrn(fd: i32, p: *u8, n: u64, want: i64) bool = {
let r: (i64 | os.oserror) = os.writeall(fd, p, n);
match (r) {
case let v: i64 => return v == want;
case let e: os.oserror => return false;
};
return false;
};
fn wrdrop(fd: i32, p: *u8, n: u64) void = {
let r: (i64 | os.oserror) = os.writeall(fd, p, n);
match (r) {
case let v: i64 => { };
case let e: os.oserror => { };
};
};
// ---- ELF constants ----------------------------------------------------
def ELFCLASS64: u8 = 2u8;
def ELFDATA2LSB: u8 = 1u8;
def EV_CURRENT_W: u32 = 1u32;
def ET_REL_W: u16 = 1u16;
def EM_X86_64_W: u16 = 62u16;
def SHT_NULL_C: u32 = 0u32;
def SHT_PROGBITS_C: u32 = 1u32;
def SHT_SYMTAB_C: u32 = 2u32;
def SHT_STRTAB_C: u32 = 3u32;
def SHT_RELA_C: u32 = 4u32;
def SHF_WRITE: u64 = 1u64;
def SHF_ALLOC: u64 = 2u64;
def SHF_EXECINSTR: u64 = 4u64;
def SHF_INFO_LINK: u64 = 64u64; // 0x40
def STB_GLOBAL: u8 = 1u8;
def STT_NOTYPE: u8 = 0u8;
def STT_OBJECT: u8 = 1u8;
def STT_FUNC: u8 = 2u8;
// Sizes of fixed structures.
def EHDR_SZ: u64 = 64u64;
def SHDR_SZ: u64 = 64u64;
def SYM_SZ: u64 = 24u64;
def RELA_SZ: u64 = 24u64;
// ---- LE byte writers (own the bytes — write into a *u8 + offset) ----
fn wru8(p: *u8, off: u64, v: u8) void = { p[off] = v; };
fn wru16(p: *u8, off: u64, v: u16) void = {
p[off] = (v & 255u16): u8;
p[off + 1u64] = ((v >> 8u16) & 255u16): u8;
};
fn wru32(p: *u8, off: u64, v: u32) void = {
p[off] = (v & 255u32): u8;
p[off + 1u64] = ((v >> 8u32) & 255u32): u8;
p[off + 2u64] = ((v >> 16u32) & 255u32): u8;
p[off + 3u64] = ((v >> 24u32) & 255u32): u8;
};
fn wru64(p: *u8, off: u64, v: u64) void = {
wru32(p, off, (v & 4294967295u64): u32);
wru32(p, off + 4u64, ((v >> 32u64) & 4294967295u64): u32);
};
// ---- growable byte buffer ---------------------------------------------
type buf = struct {
a: *arena,
p: *u8,
n: u64,
cap: u64,
};
fn bufinit(b: *buf, a: *arena) void = {
b.a = a;
b.cap = 256u64;
b.n = 0u64;
b.p = amalloc(a, b.cap): *u8;
};
fn bufgrow(b: *buf, need: u64) void = {
if (b.n + need <= b.cap) { return; };
let nc: u64 = b.cap;
for (nc < b.n + need) { nc = nc * 2u64; };
let np: *u8 = amalloc(b.a, nc): *u8;
let i: u64 = 0u64;
for (i < b.n) { np[i] = b.p[i]; i += 1u64; };
b.p = np;
b.cap = nc;
};
fn bufputb(b: *buf, src: *u8, n: u64) void = {
bufgrow(b, n);
let i: u64 = 0u64;
for (i < n) { b.p[b.n + i] = src[i]; i += 1u64; };
b.n += n;
};
// Write a NUL-terminated C-string copy of `s` into b. Returns offset
// where it started (suitable for st_name / sh_name fields).
fn bufputcstr(b: *buf, s: str) u32 = {
let off: u32 = b.n: u32;
bufgrow(b, s.len: u64 + 1u64);
let i: i32 = 0;
for (i < s.len) { b.p[b.n] = s[i]; b.n += 1u64; i += 1; };
b.p[b.n] = 0u8;
b.n += 1u64;
return off;
};
// ---- emitelf ---------------------------------------------------------
export fn emitelf(a: *asm_, fd: i32) i32 = {
let shstr: buf; bufinit(&shstr, a.a);
let str_: buf; bufinit(&str_, a.a);
let sym: buf; bufinit(&sym, a.a);
let rela: buf; bufinit(&rela, a.a);
let relad: buf; bufinit(&relad, a.a);
// Index 0 = empty.
let zero: u8 = 0u8;
bufputb(&shstr, &zero, 1u64);
bufputb(&str_, &zero, 1u64);
let hasdata: bool = a.datalen > 0u64;
let hasdatarelocs: bool = false;
let rscan: *areloc = a.relocs;
for (rscan != nil) {
if (rscan.section == 1) { hasdatarelocs = true; };
rscan = rscan.rnext;
};
// Section indices (mirror cmd/w6a/obj.c):
// without data, without data-relocs:
// 1=.text 2=.rela.text 3=.symtab 4=.strtab 5=.shstrtab
// with data, no data-relocs:
// 1=.text 2=.rela.text 3=.data 4=.symtab 5=.strtab 6=.shstrtab
// with data + data-relocs:
// 1=.text 2=.rela.text 3=.data 4=.rela.data 5=.symtab
// 6=.strtab 7=.shstrtab
let SH_TEXT: u16 = 1u16;
let SH_DATA: u16 = 0u16;
let SH_RELAD: u16 = 0u16;
let SH_SYMTAB: u16 = 3u16;
if (hasdata) {
SH_DATA = 3u16;
if (hasdatarelocs) {
SH_RELAD = 4u16;
SH_SYMTAB = 5u16;
} else {
SH_SYMTAB = 4u16;
};
};
let SH_STRTAB: u16 = SH_SYMTAB + 1u16;
let SH_SHSTR: u16 = SH_STRTAB + 1u16;
// Section name offsets. Append .data / .rela.data only when
// used so the .shstrtab buffer stays byte-identical for the
// no-DATAW case (test 991 byte-diff invariant).
let shntext: u32 = bufputcstr(&shstr, ".text");
let shnrela: u32 = bufputcstr(&shstr, ".rela.text");
let shndata: u32 = 0u32;
let shnrelad: u32 = 0u32;
if (hasdata) { shndata = bufputcstr(&shstr, ".data"); };
if (hasdata) { if (hasdatarelocs) {
shnrelad = bufputcstr(&shstr, ".rela.data");
};};
let shnsymtab: u32 = bufputcstr(&shstr, ".symtab");
let shnstrtab: u32 = bufputcstr(&shstr, ".strtab");
let shnshstrtab: u32 = bufputcstr(&shstr, ".shstrtab");
// Symbol 0 — STN_UNDEF (24 zero bytes).
let zsym: [24]u8;
let zi: i32 = 0;
for (zi < 24) { zsym[zi] = 0u8; zi += 1; };
bufputb(&sym, zsym.ptr, 24u64);
// Build symbols.
let idx: i32 = 1;
let s: *asym = a.syms;
for (s != nil) {
let entry: [24]u8;
let ei: i32 = 0;
for (ei < 24) { entry[ei] = 0u8; ei += 1; };
let stname: u32 = bufputcstr(&str_, s.name);
wru32(entry.ptr, 0u64, stname);
if (s.defined != 0) {
if (s.isdata != 0) {
wru8(entry.ptr, 4u64, ((STB_GLOBAL << 4u8) | STT_OBJECT));
wru16(entry.ptr, 6u64, SH_DATA);
} else {
wru8(entry.ptr, 4u64, ((STB_GLOBAL << 4u8) | STT_FUNC));
wru16(entry.ptr, 6u64, SH_TEXT);
};
wru64(entry.ptr, 8u64, s.addr);
} else {
wru8(entry.ptr, 4u64, ((STB_GLOBAL << 4u8) | STT_NOTYPE));
wru16(entry.ptr, 6u64, 0u16);
};
bufputb(&sym, entry.ptr, 24u64);
s.idx = idx;
idx += 1;
s = s.snext;
};
// Build relocations — split into text vs data buffers.
let r: *areloc = a.relocs;
for (r != nil) {
let entry: [24]u8;
wru64(entry.ptr, 0u64, r.off);
let rinfo: u64 = (r.asy.idx: u64 << 32u64) | (r.kind: u64 & 4294967295u64);
wru64(entry.ptr, 8u64, rinfo);
wru64(entry.ptr, 16u64, r.addend: u64);
if (r.section == 1) {
bufputb(&relad, entry.ptr, 24u64);
} else {
bufputb(&rela, entry.ptr, 24u64);
};
r = r.rnext;
};
// File offsets.
let off: u64 = EHDR_SZ;
let offtext: u64 = off; off = off + a.textlen;
let offrela: u64 = off; off = off + rela.n;
let offdata: u64 = off; if (hasdata) { off = off + a.datalen; };
let offrelad: u64 = off; if (hasdata) { if (hasdatarelocs) {
off = off + relad.n;
};};
let offsym: u64 = off; off = off + sym.n;
let offstr: u64 = off; off = off + str_.n;
let offshstr: u64 = off; off = off + shstr.n;
for ((off & 7u64) != 0u64) { off += 1u64; };
let offshdr: u64 = off;
let NSECT: u16 = 6u16;
if (hasdata) {
if (hasdatarelocs) { NSECT = 8u16; }
else { NSECT = 7u16; };
};
// ---- Ehdr ----
let eh: [64]u8;
let i: i32 = 0;
for (i < 64) { eh[i] = 0u8; i += 1; };
eh[0] = 127u8; // 0x7f
eh[1] = 69u8; // 'E'
eh[2] = 76u8; // 'L'
eh[3] = 70u8; // 'F'
eh[4] = ELFCLASS64;
eh[5] = ELFDATA2LSB;
eh[6] = EV_CURRENT_W: u8;
wru16(eh.ptr, 16u64, ET_REL_W);
wru16(eh.ptr, 18u64, EM_X86_64_W);
wru32(eh.ptr, 20u64, EV_CURRENT_W);
wru64(eh.ptr, 24u64, 0u64); // e_entry
wru64(eh.ptr, 32u64, 0u64); // e_phoff
wru64(eh.ptr, 40u64, offshdr); // e_shoff
wru32(eh.ptr, 48u64, 0u32); // e_flags
wru16(eh.ptr, 52u64, 64u16); // e_ehsize
wru16(eh.ptr, 54u64, 0u16); // e_phentsize
wru16(eh.ptr, 56u64, 0u16); // e_phnum
wru16(eh.ptr, 58u64, 64u16); // e_shentsize
wru16(eh.ptr, 60u64, NSECT); // e_shnum
wru16(eh.ptr, 62u64, SH_SHSTR); // e_shstrndx
if (!wrn(fd, eh.ptr, 64u64, 64i64)) { return -1; };
if (a.textlen > 0u64) {
if (!wrn(fd, a.text, a.textlen, a.textlen: i64)) { return -1; };
};
if (rela.n > 0u64) {
if (!wrn(fd, rela.p, rela.n, rela.n: i64)) { return -1; };
};
if (hasdata) {
if (a.datalen > 0u64) {
if (!wrn(fd, a.data, a.datalen, a.datalen: i64)) { return -1; };
};
if (hasdatarelocs) {
if (relad.n > 0u64) {
if (!wrn(fd, relad.p, relad.n, relad.n: i64)) { return -1; };
};
};
};
if (sym.n > 0u64) {
if (!wrn(fd, sym.p, sym.n, sym.n: i64)) { return -1; };
};
if (str_.n > 0u64) {
if (!wrn(fd, str_.p, str_.n, str_.n: i64)) { return -1; };
};
if (shstr.n > 0u64) {
if (!wrn(fd, shstr.p, shstr.n, shstr.n: i64)) { return -1; };
};
// Pad to 8 before shdrs.
let written: u64 = EHDR_SZ + a.textlen + rela.n + sym.n + str_.n + shstr.n;
if (hasdata) {
written += a.datalen;
if (hasdatarelocs) { written += relad.n; };
};
for ((written & 7u64) != 0u64) {
wrdrop(fd, &zero, 1u64);
written += 1u64;
};
// Section header table — 6 headers of 64 bytes each = 384 bytes.
let shbuf: [64]u8;
// SHT_NULL
let sn: i32 = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wrdrop(fd, shbuf.ptr, 64u64);
// .text
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shntext);
wru32(shbuf.ptr, 4u64, SHT_PROGBITS_C);
wru64(shbuf.ptr, 8u64, SHF_ALLOC | SHF_EXECINSTR);
wru64(shbuf.ptr, 24u64, offtext);
wru64(shbuf.ptr, 32u64, a.textlen);
wru64(shbuf.ptr, 48u64, 1u64); // sh_addralign
wrdrop(fd, shbuf.ptr, 64u64);
// .rela.text
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shnrela);
wru32(shbuf.ptr, 4u64, SHT_RELA_C);
wru64(shbuf.ptr, 8u64, SHF_INFO_LINK);
wru64(shbuf.ptr, 24u64, offrela);
wru64(shbuf.ptr, 32u64, rela.n);
wru32(shbuf.ptr, 40u64, SH_SYMTAB: u32); // sh_link
wru32(shbuf.ptr, 44u64, 1u32); // sh_info = .text idx
wru64(shbuf.ptr, 48u64, 8u64);
wru64(shbuf.ptr, 56u64, RELA_SZ);
wrdrop(fd, shbuf.ptr, 64u64);
if (hasdata) {
// .data
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shndata);
wru32(shbuf.ptr, 4u64, SHT_PROGBITS_C);
wru64(shbuf.ptr, 8u64, SHF_ALLOC | SHF_WRITE);
wru64(shbuf.ptr, 24u64, offdata);
wru64(shbuf.ptr, 32u64, a.datalen);
wru64(shbuf.ptr, 48u64, 8u64); // sh_addralign
wrdrop(fd, shbuf.ptr, 64u64);
if (hasdatarelocs) {
// .rela.data
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shnrelad);
wru32(shbuf.ptr, 4u64, SHT_RELA_C);
wru64(shbuf.ptr, 8u64, SHF_INFO_LINK);
wru64(shbuf.ptr, 24u64, offrelad);
wru64(shbuf.ptr, 32u64, relad.n);
wru32(shbuf.ptr, 40u64, SH_SYMTAB: u32);
wru32(shbuf.ptr, 44u64, SH_DATA: u32); // applies to .data
wru64(shbuf.ptr, 48u64, 8u64);
wru64(shbuf.ptr, 56u64, RELA_SZ);
wrdrop(fd, shbuf.ptr, 64u64);
};
};
// .symtab
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shnsymtab);
wru32(shbuf.ptr, 4u64, SHT_SYMTAB_C);
wru64(shbuf.ptr, 24u64, offsym);
wru64(shbuf.ptr, 32u64, sym.n);
wru32(shbuf.ptr, 40u64, SH_STRTAB: u32); // sh_link
wru32(shbuf.ptr, 44u64, 1u32); // sh_info = one local (STN_UNDEF)
wru64(shbuf.ptr, 48u64, 8u64);
wru64(shbuf.ptr, 56u64, SYM_SZ);
wrdrop(fd, shbuf.ptr, 64u64);
// .strtab
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shnstrtab);
wru32(shbuf.ptr, 4u64, SHT_STRTAB_C);
wru64(shbuf.ptr, 24u64, offstr);
wru64(shbuf.ptr, 32u64, str_.n);
wru64(shbuf.ptr, 48u64, 1u64);
wrdrop(fd, shbuf.ptr, 64u64);
// .shstrtab
sn = 0;
for (sn < 64) { shbuf[sn] = 0u8; sn += 1; };
wru32(shbuf.ptr, 0u64, shnshstrtab);
wru32(shbuf.ptr, 4u64, SHT_STRTAB_C);
wru64(shbuf.ptr, 24u64, offshstr);
wru64(shbuf.ptr, 32u64, shstr.n);
wru64(shbuf.ptr, 48u64, 1u64);
wrdrop(fd, shbuf.ptr, 64u64);
return 0;
};
// MODULE: w6a
// selfhost/cmd/w6a/main.ww — port of cmd/w6a/main.c.
//
// w6a = amd64 assembler. Read .s, parse, encode, emit ELF .o.
//
// w6a_ww -o file.o file.s
use os;
use mem;
use types;
use lex;
use parse;
use asm;
use obj;
fn cstreq(a: *u8, lit: str) bool = {
let n: u64 = lit.len: u64;
let i: u64 = 0u64;
for (i < n) {
let li: i32 = i: i32;
if (a[i] != lit[li]) { return false; };
i += 1u64;
};
if (a[i] != 0u8) { return false; };
return true;
};
fn cstrlen(p: *u8) u64 = {
let n: u64 = 0u64;
for (p[n] != 0u8) { n += 1u64; };
return n;
};
// Slurp the whole file into a fresh buffer.
fn slurp(path: *u8) (*u8, u64) = {
let fd: i32 = os.open(path, os.flag.RDONLY, 0i32);
if (fd < 0) { return nil, 0u64; };
let szr: (i64 | os.oserror) = os.filesize(fd);
let n: i64 = 0i64;
match (szr) {
case let v: i64 => n = v;
case let e: os.oserror => { os.close(fd); return nil, 0u64; };
};
let nz: u64 = n: u64;
let buf: *u8 = os.alloc(nz + 1u64): *u8;
let rr: (i64 | os.oserror) = os.readall(fd, buf, nz);
os.close(fd);
let got: i64 = 0i64;
match (rr) {
case let v: i64 => got = v;
case let e: os.oserror => return nil, 0u64;
};
if (got != n) { return nil, 0u64; };
buf[nz] = 0u8;
return buf, nz;
};
export fn main(argc: i32, argv: **u8) i32 = {
let src: *u8 = nil;
let out: *u8 = nil;
let i: i32 = 1;
for (i < argc) {
let a: *u8 = argv[i];
if (cstreq(a, "-o")) {
i += 1;
if (i >= argc) {
os.write(2, "w6a: -o requires arg\n".ptr, 20u64);
return 2;
};
out = argv[i];
} else { if (a[0u64] == 45u8) {
os.write(2, "w6a: unknown flag\n".ptr, 17u64);
return 2;
} else {
if (src != nil) {
os.write(2, "w6a: only one input\n".ptr, 19u64);
return 2;
};
src = a;
}; };
i += 1;
};
if (src == nil) {
os.write(2, "usage: w6a_ww -o file.o file.s\n".ptr, 30u64);
return 2;
};
if (out == nil) {
os.write(2, "w6a: missing -o\n".ptr, 15u64);
return 2;
};
let buf: *u8;
let blen: u64;
buf, blen = slurp(src);
if (buf == nil) {
os.write(2, "w6a: cannot read input\n".ptr, 22u64);
return 1;
};
let ar: *arena = newarena();
let asm: asm_;
let nlen: u64 = cstrlen(src);
let fname: str = astrndup(ar, src, nlen);
init(&asm, ar, fname, buf, blen);
if (parse(&asm) != 0) { return 1; };
if (encode(&asm) != 0) { return 1; };
// Open output for write.
let fd: i32 = os.open(out, os.flag.WRONLY | os.flag.CREATE | os.flag.TRUNC, 420i32); // 0o644
if (fd < 0) {
os.write(2, "w6a: cannot open output\n".ptr, 23u64);
return 1;
};
let rc: i32 = emitelf(&asm, fd);
os.close(fd);
return rc;
};
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