Files
ww/selfhost/cmd/wcc/cgen.ww
Hojun-Cho 2c33228b7e ww: rename toolchain to w-prefix + hare-style build/run/test driver
Plan 9-style w-prefix on the per-arch tools, disambiguating from the
real Plan 9 6c/6a/6l in ref/plan9front/:

    cmd/wwc/      → cmd/wcc/        libwwc.a → libwcc.a
    cmd/6{c,a,l}  → cmd/w6{c,a,l}   binary names too
    test/wwc/     → test/wcc/       6 test files w/ w6 prefix
    selfhost/cmd  mirror in lockstep
    bootstrap/amd64/{w6c,w6a,w6l}   snapshot binaries (gitignored)
    WW_6{C,A,L}   → WW_W6{C,A,L}    env-var overrides

Plan 9 source-tree refs ("Plan 9 6c shape", ref/plan9front/, etc.)
preserved. Hare-style driver, both C and ww sides:

    ww test [path]   discover *_test.ww in a directory module, run
                     each; single-file mode for `ww test foo.ww`
    Module-by-name   `ww build foo` resolves to foo.ww or foo/foo.ww
                     via search path (cwd : -I dirs : $WW_LIB)
    Default-to-cwd   `ww build` / `ww test` build the cwd module
    Run pass-through `ww run path arg1 arg2` reaches the program

lib/os: getcwd (79) and getdents64 (217) syscalls power `.` resolution
and directory enumeration on the ww side.

Makefile: wwstage tool deps now include lib/os/os.ww (+ lib/strconv
for wwdump_ww) so lib/* edits force their rebuild instead of leaving
stale binaries — surfaced when test 995 first failed against a stale
w6c_ww built before the lib/os additions.

Test 993 byte-identical parity gate (C-side ww vs ww-side ww_ww on a
build corpus) stays green; all 19 tests pass.
2026-05-11 13:49:27 +09:00

3083 lines
89 KiB
Plaintext

// selfhost/cmd/wcc/cgen.ww — port of cmd/w6c/cgen.c.
//
// Status: GROWING. Each subsystem we add is verified by `wwdump_ww -c`
// producing byte-identical output to C-side `w6c` for the same source,
// then by assembling + linking + running the result.
//
// Current coverage:
// - decls: N_FILE, N_FNDECL (params, frame for locals, prologue
// + dual-epilogue suppression; FFI body-less fn skipped)
// - stmts: N_BLOCK, N_RETURN, N_EXPRSTMT, N_LET (no init),
// N_LET (int-literal / ident / call / N_BIN init),
// N_IF (with optional else), N_FOR (cond-only and full
// init/cond/post), N_BREAK, N_CONTINUE
// - exprs: N_INTLIT, N_IDENT (local/param), N_BIN with full op
// coverage (+/-/*/// %, &/|/^, <</>>, comparisons with
// signed-vs-unsigned dispatch, &&/||), N_UN (- ! ~ &amp; *),
// N_CALL (recursive R-to-L push, pop into argregs L-to-R),
// N_ASSIGN to local idents (plain and compound +=/-=)
//
// Type info is shallow — frame slots are 8 bytes per local, all loads
// /stores are MOVQ. Programs that mix i8/i32/i64 locals work but spill
// 8 bytes per local. Float, str, slice, struct, match, defer, alloc,
// tagged-union return — none of those are wired yet.
use os;
use mem;
use ast;
use tok;
use typ;
use sym;
use strconv;
// ---- typedef alias registry -----------------------------------------
//
// `type error = str;` makes `error` a struct-shape alias. We track
// alias→target so is_str_type / is_slice_type / struct_lookup can
// resolve through the chain. Only direct N_TNAME aliases are mapped;
// `type p = struct {...}` is handled by collect_structs.
type alias_ent = struct {
aname: str,
target: *node, // the rhs type expr
aanext: *alias_ent,
};
fn collect_aliases(c: *cgen, file: *node) void = {
c.aliases = nil;
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_TYPEDECL) {
let body: *node = d.lhs;
if (body != nil) {
if (body.kind != N_TSTRUCT) {
let a: *alias_ent = amalloc(c.a, 32u64): *alias_ent;
a.aname = d.str;
a.target = body;
a.aanext = c.aliases;
c.aliases = a;
};
};
};
d = d.next;
};
};
fn alias_lookup(c: *cgen, name: str) *node = {
let a: *alias_ent = c.aliases;
for (a != nil) {
let an: str = a.aname;
if (streq(an, name)) { return a.target; };
a = a.aanext;
};
return nil;
};
// resolve_type — follow typedef alias chains to a "canonical" type
// expr (str/slice/array/struct/...). Stops on cycles via depth limit.
fn resolve_type(c: *cgen, t: *node) *node = {
let cur: *node = t;
let depth: i32 = 0;
for (depth < 16) {
if (cur == nil) { return nil; };
if (cur.kind != N_TNAME) { return cur; };
let nm: str = cur.str;
let next: *node = alias_lookup(c, nm);
if (next == nil) { return cur; };
cur = next;
depth += 1;
};
return cur;
};
// ---- struct registry ------------------------------------------------
//
// Per-file map from struct name → list of fields with computed offsets
// and sizes. Built when cg_file walks N_TYPEDECL with N_TSTRUCT lhs.
// N_DOT and N_ASSIGN consult this to resolve `s.field` for struct or
// *struct bases.
type field_info = struct {
fname: str,
foff: i32,
fsz: i32,
tnode: *node, // the field type expr, for nested struct lookups
finext: *field_info,
};
type struct_info = struct {
sname: str,
fields: *field_info,
tot_size: i32,
sinext: *struct_info,
};
// ---- locals / frame --------------------------------------------------
type local = struct {
name: str,
off: i32,
tnode: *node, // declared type expr (N_TNAME / N_TPTR / ...) or nil
lnext: *local,
};
// strlit — interned string literal record. Emitted as a DATA directive
// after all functions; cgexpr N_STRLIT loads (LEAQ ptr, MOVQ len).
type strlit = struct {
label: str, // "_S_<seq>"
bytes: str,
slnext: *strlit,
};
// ffi — `@symbol("name")` mapping. Body-less fn `foo` with this attr
// gets its CALL target rewritten to `name`.
type ffi = struct {
ident: str,
symbol: str,
fnext: *ffi,
};
def LOOP_MAX: i32 = 16;
type cgen = struct {
a: *arena,
locals: *local,
frame: i32,
last_was_return: i32,
labelseq: i32,
strlit_seq: i32,
strlits: *strlit,
ffis: *ffi,
defs: *def_ent,
fnrets: *fnret,
aliases: *alias_ent,
structs: *struct_info,
fn_name: str,
fn_ret: *node, // declared return type of current fn (or nil)
loop_top: i32,
loop_end_buf: *str, // stack of end labels for break
loop_cont_buf: *str, // stack of cont labels for continue
};
fn cgen_init(c: *cgen, a: *arena) void = {
c.a = a;
c.locals = nil;
c.frame = 0;
c.last_was_return = 0;
c.labelseq = 0;
// Note: strlit_seq, strlits, ffis are *not* reset here; they
// persist across cgfn calls within one file. cg_file resets them
// at the start of each compilation unit.
c.loop_top = 0;
c.loop_end_buf = amalloc(a, (LOOP_MAX: u64) * 16u64): *str;
c.loop_cont_buf = amalloc(a, (LOOP_MAX: u64) * 16u64): *str;
};
// local_alloc — append a slot for `name` without dedup. Used for
// match-arm bindings, which C cgen allocates via cgexpr's by-value
// `locals` list — so two separate matches each get fresh slots even
// when their bind names collide. scan_locals follows the same rule
// for N_MCASE.
fn local_alloc(c: *cgen, name: str, sz: i32, tnode: *node) i32 = {
let asz: i32 = sz;
if (asz < 8) { asz = 8; };
if ((asz & 7) != 0) { asz = (asz + 7) & ~7; };
c.frame += asz;
let off: i32 = 0 - c.frame;
let l: *local = amalloc(c.a, 48u64): *local;
l.name = name;
l.off = off;
l.tnode = tnode;
l.lnext = c.locals;
c.locals = l;
return off;
};
fn local_add(c: *cgen, name: str, sz: i32, tnode: *node) i32 = {
// Name-based slot reuse for N_LETs and params: if `name` is
// already declared in this function, return its existing
// offset. Mirrors C cgen (cmd/w6c/cgen.c:localoff). Two
// disjoint scopes that declare the same name share one slot —
// so `escape` in wwdump (three `let cp: pos;` across separate
// branches) reserves one slot, not three. scan_locals does
// the matching dedup at prologue time so the SUBQ stays in
// sync.
//
// On a dedup hit we also overwrite the stored tnode to match
// the new declaration's type. C reads `n->lhs->type` (filled
// by the checker) at every N_DOT/N_CAST site; we read
// `lc.tnode`, so it must follow source order. Without this,
// a later `let m: *node` inside a branch keeps an earlier
// `let m: i32`'s tnode and `m.next` falls into the SB fallback.
let cur: *local = c.locals;
for (cur != nil) {
let cn: str = cur.name;
if (streq(cn, name)) {
cur.tnode = tnode;
return cur.off;
};
cur = cur.lnext;
};
return local_alloc(c, name, sz, tnode);
};
// scan_seen_mark — called by scan_locals on every let / match-bind
// site. Returns true if `name` is already tracked in c.locals (so
// the slot will be shared at emission time — no new frame bump).
// Otherwise appends a name-only stub and returns false. Stubs are
// thrown away when cgfn resets c.locals before emission.
fn scan_seen_mark(c: *cgen, name: str) bool = {
if (local_find_node(c, name) != nil) { return true; };
let l: *local = amalloc(c.a, 48u64): *local;
l.name = name;
l.off = 0;
l.tnode = nil;
l.lnext = c.locals;
c.locals = l;
return false;
};
fn local_find_node(c: *cgen, name: str) *local = {
let l: *local = c.locals;
for (l != nil) {
let ln: str = l.name;
if (streq(ln, name)) { return l; };
l = l.lnext;
};
return nil;
};
fn local_find(c: *cgen, name: str) i32 = {
let l: *local = c.locals;
for (l != nil) {
let ln: str = l.name;
if (ln.len == name.len) {
let i: i32 = 0;
let eq: bool = true;
for (i < name.len) {
if (ln[i] != name[i]) { eq = false; i = name.len; }
else { i += 1; };
};
if (eq) { return l.off; };
};
l = l.lnext;
};
return 0;
};
// ---- emit helpers ---------------------------------------------------
fn emit_line(s: str) void = { os.write(1, s.ptr, s.len: u64); };
fn emit_int(v: i64) void = {
let buf: [32]u8;
let n: i32 = strconv.i64toa(buf[0:32], v);
os.write(1, buf.ptr, n: u64);
};
fn emit_uint(v: u64) void = {
let buf: [32]u8;
let n: i32 = strconv.u64toa(buf[0:32], v);
os.write(1, buf.ptr, n: u64);
};
// emit_disp_reg — print "disp(reg)" or "(reg)" when disp == 0, the
// way Plan 9 6c/6a do.
fn emit_disp_reg(off: i64, reg: str) void = {
if (off != 0i64) { emit_int(off); };
emit_line("(");
emit_line(reg);
emit_line(")");
};
// emit_off — print an integer offset, suppressing it entirely when 0.
// Use before any emit_line("(BP)...") or emit_line("(SB)...") sequence.
// Plan 9 cc convention: "(BP)" not "0(BP)".
fn emit_off(v: i64) void = {
if (v != 0i64) { emit_int(v); };
};
// mklabel — fresh label "<fnname>_<base>_<seq>". Returns an
// arena-owned str. Mirrors C cgen's mklabel so diffs match.
fn mklabel(c: *cgen, base: str) str = {
let buf: [128]u8;
let i: i32 = 0;
let fname: str = c.fn_name;
let j: i32 = 0;
for (j < fname.len) {
buf[i] = fname[j];
i += 1; j += 1;
};
buf[i] = 95u8; i += 1; // '_'
j = 0;
for (j < base.len) {
buf[i] = base[j];
i += 1; j += 1;
};
buf[i] = 95u8; i += 1; // '_'
let n: i32 = strconv.i64toa(buf[i:128], c.labelseq: i64);
c.labelseq += 1;
let total: i32 = i + n;
let p: *u8 = amalloc(c.a, (total: u64) + 1u64): *u8;
let k: i32 = 0;
for (k < total) {
p[k] = buf[k];
k += 1;
};
p[total] = 0u8;
let r: str;
r.ptr = p;
r.len = total;
return r;
};
fn emit_label(s: str) void = {
os.write(1, s.ptr, s.len: u64);
emit_line(":\n");
};
// ---- string interning ------------------------------------------------
//
// streq is provided by sym.ww and reused here.
// intern_strlit — return a stable label for `bytes`. Dedups by content
// so identical literals share storage.
fn intern_strlit(c: *cgen, bytes: str) str = {
let s: *strlit = c.strlits;
for (s != nil) {
let bs: str = s.bytes;
if (streq(bs, bytes)) {
return s.label;
};
s = s.slnext;
};
// New label "_S_<seq>".
let buf: [32]u8;
buf[0] = 95u8; buf[1] = 83u8; buf[2] = 95u8; // "_S_"
let n: i32 = strconv.i64toa(buf[3:32], c.strlit_seq: i64);
c.strlit_seq += 1;
let total: i32 = 3 + n;
let p: *u8 = amalloc(c.a, (total: u64) + 1u64): *u8;
let i: i32 = 0;
for (i < total) { p[i] = buf[i]; i += 1; };
p[total] = 0u8;
let lab: str;
lab.ptr = p;
lab.len = total;
let nw: *strlit = amalloc(c.a, 48u64): *strlit;
nw.label = lab;
nw.bytes = bytes;
nw.slnext = c.strlits;
c.strlits = nw;
return lab;
};
// emit_def_constants — DATA directive per top-level int-literal `def`.
// 8 bytes little-endian to match what the C cgen emits.
fn emit_def_constants(c: *cgen, file: *node) void = {
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_DEF) {
let r: *node = d.rhs;
let v: u64 = 0u64;
let ok: bool = false;
if (r != nil) {
if (r.kind == N_INTLIT) { v = r.uval; ok = true; };
if (r.kind == N_RUNELIT) { v = r.uval; ok = true; };
if (r.kind == N_TRUE) { v = 1u64; ok = true; };
if (r.kind == N_FALSE) { v = 0u64; ok = true; };
if (r.kind == N_NIL) { v = 0u64; ok = true; };
};
if (ok) {
emit_line("DATA ");
let nm: str = d.str;
os.write(1, nm.ptr, nm.len: u64);
emit_line("(SB),\"");
let i: i32 = 0;
let n: u64 = v;
for (i < 8) {
let b: u8 = (n & 255u64): u8;
n = n >> 8u64;
// C emit_defs only special-cases " and \;
// every other non-printable goes as \xHH.
if (b == 34u8) { emit_line("\\\""); }
else { if (b == 92u8) { emit_line("\\\\"); }
else {
if (b < 32u8) {
emit_line("\\x");
let hi: u8 = b >> 4u8;
let lo: u8 = b & 15u8;
let bb: [2]u8;
if (hi < 10u8) { bb[0] = hi + 48u8; }
else { bb[0] = (hi - 10u8) + 97u8; };
if (lo < 10u8) { bb[1] = lo + 48u8; }
else { bb[1] = (lo - 10u8) + 97u8; };
os.write(1, bb.ptr, 2u64);
} else {
if (b >= 127u8) {
emit_line("\\x");
let hi: u8 = b >> 4u8;
let lo: u8 = b & 15u8;
let bb: [2]u8;
if (hi < 10u8) { bb[0] = hi + 48u8; }
else { bb[0] = (hi - 10u8) + 97u8; };
if (lo < 10u8) { bb[1] = lo + 48u8; }
else { bb[1] = (lo - 10u8) + 97u8; };
os.write(1, bb.ptr, 2u64);
} else {
let bb: [1]u8;
bb[0] = b;
os.write(1, bb.ptr, 1u64);
};
};
};};
i += 1;
};
emit_line("\"\n");
};
};
d = d.next;
};
};
// emit_data_section — DATA directives for every interned strlit.
// Trailing NUL appended so .ptr can be used as a C string by syscalls.
fn emit_data_section(c: *cgen) void = {
let s: *strlit = c.strlits;
for (s != nil) {
emit_line("DATA ");
let lab: str = s.label;
os.write(1, lab.ptr, lab.len: u64);
emit_line("(SB),\"");
let bs: str = s.bytes;
let i: i32 = 0;
for (i < bs.len) {
let b: u8 = bs[i];
if (b == 34u8) { emit_line("\\\""); } // "
else { if (b == 92u8) { emit_line("\\\\"); } // \
else { if (b == 10u8) { emit_line("\\n"); }
else { if (b == 9u8) { emit_line("\\t"); }
else { if (b == 13u8) { emit_line("\\r"); }
else {
if (b < 32u8) {
emit_line("\\x");
let hi: u8 = b >> 4u8;
let lo: u8 = b & 15u8;
let bb: [2]u8;
if (hi < 10u8) { bb[0] = hi + 48u8; }
else { bb[0] = (hi - 10u8) + 97u8; };
if (lo < 10u8) { bb[1] = lo + 48u8; }
else { bb[1] = (lo - 10u8) + 97u8; };
os.write(1, bb.ptr, 2u64);
} else {
if (b >= 127u8) {
emit_line("\\x");
let hi: u8 = b >> 4u8;
let lo: u8 = b & 15u8;
let bb: [2]u8;
if (hi < 10u8) { bb[0] = hi + 48u8; }
else { bb[0] = (hi - 10u8) + 97u8; };
if (lo < 10u8) { bb[1] = lo + 48u8; }
else { bb[1] = (lo - 10u8) + 97u8; };
os.write(1, bb.ptr, 2u64);
} else {
let bb: [1]u8;
bb[0] = b;
os.write(1, bb.ptr, 1u64);
};
};
};};};};};
i += 1;
};
emit_line("\\x00\"\n");
s = s.slnext;
};
};
// ---- fn return-type map ---------------------------------------------
//
// Per-file: ident → ret-type-node. Used to decide whether to shuffle
// (AX, DX) → (AX, BX) after a CALL — needed for str-returning fns so
// the value flows through cgen as the canonical (AX, BX) str pair.
type fnret = struct {
fname: str,
rtype: *node,
frnext: *fnret,
};
fn collect_fnrets(c: *cgen, file: *node) void = {
c.fnrets = nil;
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_FNDECL) {
let f: *fnret = amalloc(c.a, 32u64): *fnret;
f.fname = d.str;
f.rtype = d.lhs;
f.frnext = c.fnrets;
c.fnrets = f;
};
d = d.next;
};
};
fn fnret_lookup(c: *cgen, name: str) *node = {
let f: *fnret = c.fnrets;
for (f != nil) {
let fn_: str = f.fname;
if (streq(fn_, name)) { return f.rtype; };
f = f.frnext;
};
return nil;
};
// ---- def-constant registry ------------------------------------------
//
// `def NAME: T = LIT;` becomes a DATA symbol the C-side w6c emits; an
// ident reference loads it via `MOVQ NAME(SB), AX`. We collect them at
// file load and consult on N_IDENT lookup.
type def_ent = struct {
dname: str,
dnext: *def_ent,
};
fn collect_defs(c: *cgen, file: *node) void = {
c.defs = nil;
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_DEF) {
let e: *def_ent = amalloc(c.a, 32u64): *def_ent;
e.dname = d.str;
e.dnext = c.defs;
c.defs = e;
};
d = d.next;
};
};
fn def_lookup(c: *cgen, name: str) bool = {
let e: *def_ent = c.defs;
for (e != nil) {
let dn: str = e.dname;
if (streq(dn, name)) { return true; };
e = e.dnext;
};
return false;
};
// ---- FFI map ---------------------------------------------------------
fn ffi_collect(c: *cgen, file: *node) void = {
c.ffis = nil;
if (file == nil) { return; };
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_FNDECL) {
let a: *node = d.attr;
for (a != nil) {
if (a.kind == N_ATTR) {
let aname: str = a.str;
if (streq(aname, "symbol")) {
let sym_node: *node = a.list;
if (sym_node != nil) {
if (sym_node.kind == N_STRLIT) {
let f: *ffi = amalloc(c.a, 48u64): *ffi;
f.ident = d.str;
f.symbol = sym_node.str;
f.fnext = c.ffis;
c.ffis = f;
};
};
};
};
a = a.next;
};
};
d = d.next;
};
};
fn ffi_resolve(c: *cgen, ident: str) str = {
let f: *ffi = c.ffis;
for (f != nil) {
let id: str = f.ident;
if (streq(id, ident)) { return f.symbol; };
f = f.fnext;
};
return ident;
};
// ---- ABI argreg helpers ---------------------------------------------
fn argreg_name(i: i32) str = {
if (i == 0) { return "DI"; };
if (i == 1) { return "SI"; };
if (i == 2) { return "DX"; };
if (i == 3) { return "CX"; };
if (i == 4) { return "R8"; };
if (i == 5) { return "R9"; };
return "?";
};
// ---- expression cgen -------------------------------------------------
// push_args_rev — recursively walks the arg list, evaluates rightmost
// first, and pushes. str args take two slots (ptr in AX, len in BX);
// the order on the stack so a left-to-right pop into argregs lands
// (ptr, len) correctly is: PUSHQ BX (top), PUSHQ AX (above) — the
// pop sequence then yields AX, then BX.
fn push_args_rev(c: *cgen, arg: *node) i32 = {
if (arg == nil) { return 0; };
let rest: i32 = push_args_rev(c, arg.next);
// N_SLICE expression as arg: `buf[lo:hi]` builds a slice header
// on the stack matching C cgen's sequence — push base, push hi,
// compute lo, pop into BX/CX, derive len/ptr, push (cap, len, ptr).
if (arg.kind == N_SLICE) {
let base: *node = arg.lhs;
let lo: *node = arg.rhs;
let hi: *node = arg.cond;
let base_local: *local = nil;
if (base != nil) {
if (base.kind == N_IDENT) {
let bn: str = base.str;
base_local = local_find_node(c, bn);
};
};
// base address → push
if (base_local != nil) {
let tn: *node = base_local.tnode;
if (tn != nil) {
if (tn.kind == N_TARRAY) {
emit_line("\tLEAQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), AX\n");
} else {
emit_line("\tMOVQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), AX\n");
};
} else {
emit_line("\tMOVQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), AX\n");
};
} else {
cgexpr(c, base);
};
emit_line("\tPUSHQ\tAX\n");
// hi (default base length) → push
if (hi != nil) {
cgexpr(c, hi);
} else { if (base_local != nil) {
let tn: *node = base_local.tnode;
if (tn != nil) {
if (tn.kind == N_TARRAY) {
let len_n: *node = tn.rhs;
if (len_n != nil) {
if (len_n.kind == N_INTLIT) {
emit_line("\tMOVQ\t$");
emit_uint(len_n.uval);
emit_line(", AX\n");
};
};
} else { if (tn.kind == N_TSLICE) {
emit_line("\tMOVQ\t");
emit_off((base_local.off + 8): i64);
emit_line("(BP), AX\n");
} else { if (tn.kind == N_TNAME) {
if (streq(tn.str, "str")) {
emit_line("\tMOVQ\t");
emit_off((base_local.off + 8): i64);
emit_line("(BP), AX\n");
};
};};};
};
} else {
emit_line("\tMOVQ\t$0, AX\n");
};};
emit_line("\tPUSHQ\tAX\n");
// lo (default 0) → AX
if (lo != nil) { cgexpr(c, lo); }
else { emit_line("\tMOVQ\t$0, AX\n"); };
emit_line("\tPOPQ\tBX\n"); // hi
emit_line("\tPOPQ\tCX\n"); // base
emit_line("\tMOVQ\tBX, DX\n"); // DX = hi
emit_line("\tSUBQ\tAX, DX\n"); // DX = hi - lo = len
emit_line("\tADDQ\tAX, CX\n"); // CX = base + lo = ptr
emit_line("\tPUSHQ\tDX\n"); // cap
emit_line("\tPUSHQ\tDX\n"); // len
emit_line("\tPUSHQ\tCX\n"); // ptr (top)
return rest + 3;
};
// Slice/tagged ident args: emit per-register MOVQ+PUSHQ pairs in
// reverse order (cap/v1, len/v0, ptr/tag) so a left-to-right pop
// into argregs lands the canonical (ptr/tag, len/v0, cap/v1).
if (arg.kind == N_IDENT) {
let nm: str = arg.str;
let lc: *local = local_find_node(c, nm);
if (lc != nil) {
let off: i32 = lc.off;
if (is_slice_type(c, lc.tnode) || is_tagged_type(lc.tnode)) {
emit_line("\tMOVQ\t");
emit_off((off + 16): i64);
emit_line("(BP), AX\n");
emit_line("\tPUSHQ\tAX\n");
emit_line("\tMOVQ\t");
emit_off((off + 8): i64);
emit_line("(BP), AX\n");
emit_line("\tPUSHQ\tAX\n");
emit_line("\tMOVQ\t");
emit_off(off: i64);
emit_line("(BP), AX\n");
emit_line("\tPUSHQ\tAX\n");
return rest + 3;
};
};
};
cgexpr(c, arg);
if (node_isslice(c, arg)) {
emit_line("\tPUSHQ\tCX\n");
emit_line("\tPUSHQ\tBX\n");
emit_line("\tPUSHQ\tAX\n");
return rest + 3;
};
if (node_isstr(c, arg)) {
emit_line("\tPUSHQ\tBX\n");
emit_line("\tPUSHQ\tAX\n");
return rest + 2;
};
emit_line("\tPUSHQ\tAX\n");
return rest + 1;
};
fn node_isslice(c: *cgen, n: *node) bool = {
if (n == nil) { return false; };
let k: i32 = n.kind;
if (k == N_IDENT) {
let nm: str = n.str;
let lc: *local = local_find_node(c, nm);
if (lc != nil) { return is_slice_type(c, lc.tnode); };
return false;
};
if (k == N_SLICE) { return true; };
return false;
};
// node_isstr — best-effort surface check: does this expression
// evaluate to a str value? Used to drive the call-arg push convention
// (str args take two slots: ptr + len).
fn node_isstr(c: *cgen, n: *node) bool = {
if (n == nil) { return false; };
let k: i32 = n.kind;
if (k == N_STRLIT) { return true; };
if (k == N_IDENT) {
let nm: str = n.str;
let lc: *local = local_find_node(c, nm);
if (lc != nil) {
let tn: *node = lc.tnode;
if (tn != nil) {
if (tn.kind == N_TNAME) {
let tnm: str = tn.str;
if (streq(tnm, "str")) { return true; };
};
};
};
return false;
};
if (k == N_CALL) {
let callee: *node = n.lhs;
if (callee != nil) {
if (callee.kind == N_IDENT) {
let cnm: str = callee.str;
let rt: *node = fnret_lookup(c, cnm);
return is_str_type(c, rt);
};
};
return false;
};
if (k == N_DOT) {
let base: *node = n.lhs;
let fld: str = n.str;
// `<expr>.ptr` is *u8 not str; `<expr>.len` is i32 not str.
if (streq(fld, "ptr")) { return false; };
if (streq(fld, "len")) { return false; };
if (streq(fld, "cap")) { return false; };
if (base != nil) {
let sname: str;
sname.ptr = nil; sname.len = 0;
if (base.kind == N_IDENT) {
let lc: *local = local_find_node(c, base.str);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: i32 = -1;
if (tn != nil) { lkind = tn.kind; };
if (lkind == N_TNAME) { sname = tn.str; };
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
if (inner != nil) {
if (inner.kind == N_TNAME) { sname = inner.str; };
};
};
};
};
// Chained dot (`p.foo.bar`): use dot_inner_struct_ptr
// to resolve the inner chain to the *struct it lands
// on, then look up `fld` in that struct.
if (base.kind == N_DOT) {
let inner_t: *node = dot_inner_struct_ptr(c, base);
if (inner_t != nil) {
if (inner_t.kind == N_TNAME) { sname = inner_t.str; };
};
};
if (sname.len > 0) {
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
return is_str_type(c, fi.tnode);
};
fi = fi.finext;
};
};
};
};
return false;
};
if (k == N_CAST) {
return is_str_type(c, n.rhs);
};
return false;
};
// type_name_isunsigned — true for u8/u16/u32/u64/uint/uintptr.
fn type_name_isunsigned(nm: str) bool = {
if (streq(nm, "u8")) { return true; };
if (streq(nm, "u16")) { return true; };
if (streq(nm, "u32")) { return true; };
if (streq(nm, "u64")) { return true; };
if (streq(nm, "uint")) { return true; };
if (streq(nm, "uintptr")) { return true; };
return false;
};
// type_node_isunsigned — recurse through TNAME / TPTR / TSLICE etc.
fn type_node_isunsigned(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind == N_TNAME) { return type_name_isunsigned(t.str); };
return false;
};
// type_is_8byte_primitive — does this type take exactly one 8-byte
// slot (pointer / fn-ptr / 64-bit int / chan / scalar primitive
// padded up to 8) rather than a wider aggregate? Used by N_LET
// zero-init to mirror C cgen's "only zero if sz == 8 at the type
// level" rule. Strings (16), slices (24), tagged unions (>=16),
// tuples (16), structs (varies), arrays — all fall through to
// false here even when their *slot* rounds up to 8.
fn type_is_8byte_primitive(c: *cgen, t: *node) bool = {
if (t == nil) { return false; };
let k: i32 = t.kind;
if (k == N_TPTR) { return true; };
if (k == N_TFN) { return true; };
if (k == N_TCHAN) { return true; };
if (k == N_TSLICE) { return false; };
if (k == N_TARRAY) { return false; };
if (k == N_TTUPLE) { return false; };
if (k == N_TTAGGED){ return false; };
if (k == N_TNAME) {
let nm: str = t.str;
if (streq(nm, "str")) { return false; };
// Struct alias: not a primitive even if the slot is 8B.
if (struct_lookup(c, nm) != nil) { return false; };
// Primitive (i8/u8/.../i64/u64/bool/rune/f32/f64/int/...).
// All of these get slot-padded to 8 and zero-init in C.
if (prim_size(nm) > 0) { return true; };
return false;
};
return false;
};
// type_name_issigned — true for i8/i16/i32/i64/int/rune.
fn type_name_issigned(nm: str) bool = {
if (streq(nm, "i8")) { return true; };
if (streq(nm, "i16")) { return true; };
if (streq(nm, "i32")) { return true; };
if (streq(nm, "i64")) { return true; };
if (streq(nm, "int")) { return true; };
if (streq(nm, "rune")) { return true; };
return false;
};
// field_load_op — pick the load instruction for a non-str struct
// field by its declared size + signedness. Mirrors the C cgen op
// dispatch (MOVZBQ for u8/bool/i8, MOVSXD for i32, MOVL for u32, MOVQ
// for 8-byte). f might be nil for fields outside our struct registry.
fn field_load_op(f: *field_info) str = {
if (f == nil) { return "MOVQ"; };
let sz: i32 = f.fsz;
if (sz == 1) { return "MOVZBQ"; };
if (sz == 4) {
let t: *node = f.tnode;
if (t != nil) {
if (t.kind == N_TNAME) {
if (type_name_issigned(t.str)) { return "MOVSXD"; };
};
};
return "MOVL";
};
return "MOVQ";
};
// field_store_op — pick the store instruction for a non-str struct
// field by its declared size. MOVB for 1, MOVL for 4, MOVQ for 8.
fn field_store_op(f: *field_info) str = {
if (f == nil) { return "MOVQ"; };
let sz: i32 = f.fsz;
if (sz == 1) { return "MOVB"; };
if (sz == 4) { return "MOVL"; };
return "MOVQ";
};
// index_base_esz — element size for `arr[i]` where the base is a
// chained-dot pseudo-field `s.ptr` (s being str/*str/slice/*slice).
// For str the element is one byte; for `[]T` / `*[]T` we drill into
// the slice element type.
fn index_base_esz(c: *cgen, base: *node) i32 = {
if (base == nil) { return 8; };
if (base.kind != N_DOT) { return 8; };
let fld: str = base.str;
let inner: *node = base.lhs;
if (inner == nil) { return 8; };
if (inner.kind != N_IDENT) { return 8; };
let nm: str = inner.str;
let lc: *local = local_find_node(c, nm);
if (lc == nil) { return 8; };
let tn: *node = lc.tnode;
if (tn == nil) { return 8; };
// `.ptr` pseudo-field on str/slice → element of the str/slice.
if (streq(fld, "ptr")) {
let inner_t: *node = tn;
if (tn.kind == N_TPTR) { inner_t = tn.lhs; };
if (inner_t == nil) { return 8; };
if (inner_t.kind == N_TNAME) {
if (streq(inner_t.str, "str")) { return 1; };
};
if (inner_t.kind == N_TSLICE) { return elem_size_of(inner_t); };
return 8;
};
// Generic struct field: if it's *T, element size is T's size.
let lkind: i32 = tn.kind;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (lkind == N_TNAME) { sname = tn.str; };
if (lkind == N_TPTR) {
let pinner: *node = tn.lhs;
if (pinner != nil) {
if (pinner.kind == N_TNAME) { sname = pinner.str; };
};
};
if (sname.len == 0) { return 8; };
let si: *struct_info = struct_lookup(c, sname);
if (si == nil) { return 8; };
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
let ft: *node = fi.tnode;
if (ft == nil) { return 8; };
if (ft.kind == N_TPTR) {
let elem: *node = ft.lhs;
if (elem != nil) {
if (elem.kind == N_TNAME) {
if (streq(elem.str, "str")) { return 16; };
let ps: i32 = prim_size(elem.str);
if (ps > 0) { return ps; };
};
};
return 8;
};
if (ft.kind == N_TSLICE) { return elem_size_of(ft); };
// str-typed field: indexing yields one byte
// (`n.s[i]` where .s is str — matches C cgen's
// MOVZBQ for byte indexing).
if (ft.kind == N_TNAME) {
if (streq(ft.str, "str")) { return 1; };
};
return 8;
};
fi = fi.finext;
};
return 8;
};
// dot_inner_struct_ptr — for an N_DOT whose lhs is a chain of dots
// or an N_IDENT, walk the chain and return the N_TNAME tnode of the
// struct that the chain dereferences to (i.e., for `r.sym` where
// .sym is *lsym, return N_TNAME("lsym")). Returns nil if the chain
// doesn't resolve to a *struct.
//
// Used by the chained-DOT cgen path so `r.sym.val` knows the outer
// is a field of `lsym`.
fn dot_inner_struct_ptr(c: *cgen, n: *node) *node = {
if (n == nil) { return nil; };
if (n.kind != N_DOT) { return nil; };
let base: *node = n.lhs;
let fld: str = n.str;
if (base == nil) { return nil; };
// Resolve base's struct tnode.
let base_t: *node = nil;
if (base.kind == N_IDENT) {
let lc: *local = local_find_node(c, base.str);
if (lc == nil) { return nil; };
let tn: *node = lc.tnode;
if (tn == nil) { return nil; };
// base could be either struct-by-value (N_TNAME) or *struct (N_TPTR).
if (tn.kind == N_TNAME) { base_t = tn; };
if (tn.kind == N_TPTR) { base_t = tn.lhs; };
} else { if (base.kind == N_DOT) {
base_t = dot_inner_struct_ptr(c, base);
};};
if (base_t == nil) { return nil; };
if (base_t.kind != N_TNAME) { return nil; };
// Look up the struct, find the field, return the field's *struct.
let si: *struct_info = struct_lookup(c, base_t.str);
if (si == nil) { return nil; };
let fi: *field_info = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
let ft: *node = fi.tnode;
if (ft == nil) { return nil; };
if (ft.kind != N_TPTR) { return nil; };
let inner: *node = ft.lhs;
if (inner == nil) { return nil; };
if (inner.kind != N_TNAME) { return nil; };
return inner;
};
fi = fi.finext;
};
return nil;
};
// elem_size_of — given the type node of an indexable (`*T`, `[]T`,
// `[N]T`, `str`), return the byte size of one element (1 for u8/i8/
// bool/str-byte, 8 otherwise — same shape as C cgen's esz fallback).
fn elem_size_of(t: *node) i32 = {
if (t == nil) { return 1; };
let k: i32 = t.kind;
let elem: *node = nil;
if (k == N_TPTR) { elem = t.lhs; };
if (k == N_TSLICE) { elem = t.lhs; };
if (k == N_TARRAY) { elem = t.lhs; };
if (k == N_TNAME) {
let nm: str = t.str;
if (streq(nm, "str")) { return 1; };
// Indexing a primitive name (rare): element size = the prim.
let ps: i32 = prim_size(nm);
if (ps > 0) { return ps; };
return 1;
};
if (elem == nil) { return 1; };
if (elem.kind == N_TNAME) {
let nm: str = elem.str;
// str element is 16B (ptr+len). prim_size returns 0 for it.
if (streq(nm, "str")) { return 16; };
let ps: i32 = prim_size(nm);
if (ps > 0) { return ps; };
};
return 8;
};
// node_isunsigned — best-effort cgen-time inference from the AST. We
// don't have a typed AST yet, so we walk surface nodes:
// N_INTLIT — never marked unsigned (no tsuffix plumbing yet)
// N_IDENT — look up the local's declared type
// N_DOT — look up the field's declared type via struct reg
// N_BIN / N_UN — recurse: unsigned if either operand is unsigned
// N_CAST — use the cast target type
//
// Conservative: if we can't tell, return false (signed). The cost of
// being wrong here is byte-different asm vs C, not bad runtime.
fn node_isunsigned(c: *cgen, n: *node) bool = {
if (n == nil) { return false; };
let k: i32 = n.kind;
if (k == N_IDENT) {
let nm: str = n.str;
let lc: *local = local_find_node(c, nm);
if (lc != nil) { return type_node_isunsigned(lc.tnode); };
return false;
};
if (k == N_DOT) {
let base: *node = n.lhs;
let fld: str = n.str;
if (base != nil) {
if (base.kind == N_IDENT) {
let bn: str = base.str;
let lc: *local = local_find_node(c, bn);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: i32 = -1;
if (tn != nil) { lkind = tn.kind; };
let sname: str;
sname.ptr = nil; sname.len = 0;
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
if (inner != nil) {
if (inner.kind == N_TNAME) { sname = inner.str; };
};
};
if (lkind == N_TNAME) { sname = tn.str; };
if (sname.len > 0) {
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
return type_node_isunsigned(fi.tnode);
};
fi = fi.finext;
};
};
};
};
};
};
return false;
};
if (k == N_CAST) { return type_node_isunsigned(n.rhs); };
if (k == N_BIN) {
if (node_isunsigned(c, n.lhs)) { return true; };
return node_isunsigned(c, n.rhs);
};
if (k == N_UN) { return node_isunsigned(c, n.lhs); };
// N_INDEX: `p[i]` is unsigned iff p's element type is unsigned.
// Walks the base local's declared type and pulls the element
// out — *u8 → u8, [N]u32 → u32, []u64 → u64. Without this the
// compare-codegen for `p[i] >= 48u8` falls back to signed JGE
// instead of JAE, diverging from C w6c on byte indexing.
if (k == N_INDEX) {
let base: *node = n.lhs;
if (base != nil) {
if (base.kind == N_IDENT) {
let lc: *local = local_find_node(c, base.str);
if (lc != nil) {
let tn: *node = lc.tnode;
if (tn != nil) {
let elem: *node = nil;
if (tn.kind == N_TPTR) { elem = tn.lhs; };
if (tn.kind == N_TARRAY) { elem = tn.lhs; };
if (tn.kind == N_TSLICE) { elem = tn.lhs; };
if (elem != nil) {
return type_node_isunsigned(elem);
};
};
};
};
};
return false;
};
return false;
};
fn cgexpr(c: *cgen, n: *node) void = {
if (n == nil) { return; };
let k: i32 = n.kind;
if (k == N_INTLIT) {
// Print signed (i64), not unsigned (u64). C cgen uses
// `$%lld` so 64-bit constants with bit 63 set show up as
// negative — e.g. FNV-1a's offset basis prints as
// $-3750763034362895579, not $14695981039346656037.
emit_line("\tMOVQ\t$");
emit_int(n.uval: i64);
emit_line(", AX\n");
return;
};
if (k == N_RUNELIT) {
emit_line("\tMOVQ\t$");
emit_int(n.uval: i64);
emit_line(", AX\n");
return;
};
if (k == N_STRLIT) {
// Result is the (ptr, len) pair: ptr in AX, len in BX. Call
// sites that expect a str arg pick these up directly.
let nstr: str = n.str;
let lab: str = intern_strlit(c, nstr);
emit_line("\tLEAQ\t");
os.write(1, lab.ptr, lab.len: u64);
emit_line("(SB), AX\n");
emit_line("\tMOVQ\t$");
emit_int(nstr.len: i64);
emit_line(", BX\n");
return;
};
if (k == N_TRUE) {
emit_line("\tMOVQ\t$1, AX\n");
return;
};
if (k == N_FALSE) {
emit_line("\tMOVQ\t$0, AX\n");
return;
};
if (k == N_NIL) {
emit_line("\tMOVQ\t$0, AX\n");
return;
};
if (k == N_IDENT) {
let nm: str = n.str;
let lc: *local = local_find_node(c, nm);
if (lc != nil) {
let off: i32 = lc.off;
emit_line("\tMOVQ\t");
emit_off(off: i64);
emit_line("(BP), AX\n");
// str local: also load the len half into BX.
if (is_str_type(c, lc.tnode)) {
emit_line("\tMOVQ\t");
emit_off((off + 8): i64);
emit_line("(BP), BX\n");
};
// slice local: load (ptr, len, cap) into (AX, BX, CX).
if (is_slice_type(c, lc.tnode)) {
emit_line("\tMOVQ\t");
emit_off((off + 8): i64);
emit_line("(BP), BX\n");
emit_line("\tMOVQ\t");
emit_off((off + 16): i64);
emit_line("(BP), CX\n");
};
return;
};
// Top-level `def` constant — load from its DATA symbol.
if (def_lookup(c, nm)) {
emit_line("\tMOVQ\t");
os.write(1, nm.ptr, nm.len: u64);
emit_line("(SB), AX\n");
return;
};
// Fn-name used as a value (e.g. `let f = some_fn;` or
// `... = some_fn;`). LEAQ the symbol address into AX —
// resolved through ffi_resolve so a body-less FFI binding
// emits the C symbol it was declared with via @symbol(),
// not the ww-side ident.
let rt: *node = fnret_lookup(c, nm);
if (rt != nil) {
let resolved: str = ffi_resolve(c, nm);
emit_line("\tLEAQ\t");
os.write(1, resolved.ptr, resolved.len: u64);
emit_line("(SB), AX\n");
return;
};
return;
};
if (k == N_INDEX) {
// Element-size-aware load: u8-element bases use MOVZBQ,
// everything else MOVQ. Fast path when the base is a bare
// ident (mem.ww shape).
let base: *node = n.lhs;
let idx: *node = n.rhs;
let esz: i32 = 8;
let base_local: *local = nil;
if (base != nil) {
if (base.kind == N_IDENT) {
let bn: str = base.str;
base_local = local_find_node(c, bn);
if (base_local != nil) { esz = elem_size_of(base_local.tnode); };
} else { if (base.kind == N_DOT) {
esz = index_base_esz(c, base);
};};
};
cgexpr(c, idx);
if (esz > 1) {
emit_line("\tMOVQ\t$");
emit_int(esz: i64);
emit_line(", CX\n");
emit_line("\tIMULQ\tCX, AX\n");
};
if (base_local != nil) {
let tn: *node = base_local.tnode;
let is_array: bool = false;
if (tn != nil) { if (tn.kind == N_TARRAY) { is_array = true; }; };
if (is_array) {
emit_line("\tLEAQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), BX\n");
} else {
emit_line("\tMOVQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), BX\n");
};
emit_line("\tADDQ\tAX, BX\n");
// str element (16B): load (ptr, len) into (AX, BX) so
// the value flows through the str-rhs convention.
if (esz == 16) {
emit_line("\tMOVQ\t8(BX), CX\n");
emit_line("\tMOVQ\t(BX), AX\n");
emit_line("\tMOVQ\tCX, BX\n");
return;
};
if (esz == 1) { emit_line("\tMOVZBQ\t(BX), AX\n"); }
else { emit_line("\tMOVQ\t(BX), AX\n"); };
return;
};
// Generic fallback when base isn't a plain ident.
emit_line("\tPUSHQ\tAX\n");
cgexpr(c, base);
emit_line("\tPOPQ\tBX\n");
emit_line("\tADDQ\tBX, AX\n");
if (esz == 16) {
emit_line("\tMOVQ\t8(AX), BX\n");
emit_line("\tMOVQ\t(AX), AX\n");
return;
};
if (esz == 1) { emit_line("\tMOVZBQ\t(AX), AX\n"); }
else { emit_line("\tMOVQ\t(AX), AX\n"); };
return;
};
if (k == N_MATCH) {
// match (e) { case let v: T => stmt; ... }
//
// Read the tagged-union slot and dispatch by tag. Slot
// layout: [+0]=tag, [+8]=value0, [+16]=value1. Bindings
// (`case let v: T =>`) get a fresh local slot loaded from
// slot+8 (and slot+16 for str-typed payload).
let scrut: *node = n.lhs;
let scrut_off: i32 = 0;
let scrut_t: *node = nil;
if (scrut != nil) {
if (scrut.kind == N_IDENT) {
let lc: *local = local_find_node(c, scrut.str);
if (lc != nil) {
scrut_off = lc.off;
scrut_t = resolve_type(c, lc.tnode);
};
};
};
let endl: str = mklabel(c, "match_end");
let cs: *node = n.list;
for (cs != nil) {
let nxt: str = mklabel(c, "match_next");
let pat: *node = cs.lhs;
// Compute the variant tag for this arm. Default arm
// (no pattern) skips the tag check.
if (pat != nil) {
let want: i32 = 0;
if (scrut_t != nil) {
if (scrut_t.kind == N_TTAGGED) {
let pat_name: str;
pat_name.ptr = nil; pat_name.len = 0;
if (pat.kind == N_TNAME) { pat_name = pat.str; };
let v: *node = scrut_t.list;
let idx: i32 = 0;
let found: bool = false;
for (v != nil) {
if (v.kind == N_TNAME) {
if (streq(v.str, pat_name)) {
want = idx;
found = true;
v = nil;
};
};
if (v != nil) {
v = v.next;
idx += 1;
};
};
if (!found) { want = 0; };
};
};
emit_line("\tMOVQ\t");
emit_off(scrut_off: i64);
emit_line("(BP), AX\n");
emit_line("\tCMPQ\t$");
emit_int(want: i64);
emit_line(", AX\n");
emit_line("\tJNE\t");
emit_line(nxt);
emit_line("\n");
};
// Bind `let v: T` from the slot, if requested.
let bn: str = cs.str;
if (bn.len > 0) {
if (pat != nil) {
let bsz: i32 = 8;
if (is_str_type(c, pat)) { bsz = 16; };
// local_alloc (not local_add): match-arm
// binds don't dedup with same-named binds
// in *other* matches, since C's cgexpr
// allocates a fresh slot per match expr.
let voff: i32 = local_alloc(c, bn, bsz, pat);
emit_line("\tMOVQ\t");
emit_off((scrut_off + 8): i64);
emit_line("(BP), AX\n");
emit_line("\tMOVQ\tAX, ");
emit_off(voff: i64);
emit_line("(BP)\n");
if (bsz == 16) {
emit_line("\tMOVQ\t");
emit_off((scrut_off + 16): i64);
emit_line("(BP), AX\n");
emit_line("\tMOVQ\tAX, ");
emit_off((voff + 8): i64);
emit_line("(BP)\n");
};
};
};
// Body. Match arms are statements; we cgstmt them.
if (cs.body != nil) { cgstmt(c, cs.body); };
emit_line("\tJMP\t");
emit_line(endl);
emit_line("\n");
emit_label(nxt);
cs = cs.next;
};
emit_label(endl);
return;
};
if (k == N_CAST) {
// Type casts are mostly no-ops at the asm level for our
// integer-shaped operands. Evaluate the source; AX holds
// the bits unchanged. (Sign- or zero-extending narrow loads
// to wider types is the loader's job, not cast's, in this
// minimal cgen.)
cgexpr(c, n.lhs);
return;
};
if (k == N_DOT) {
let lhs: *node = n.lhs;
let fld: str = n.str;
if (lhs != nil) {
if (lhs.kind == N_IDENT) {
let nm: str = lhs.str;
let lc: *local = local_find_node(c, nm);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: i32 = -1;
if (tn != nil) { lkind = tn.kind; };
// Pointer-to-struct: deref then field load.
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (inner != nil) {
if (inner.kind == N_TNAME) {
sname = inner.str;
};
};
if (sname.len > 0) {
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
// str field via *struct: load len into a
// scratch first (so loading ptr into AX
// last leaves (AX=ptr, BX=len)).
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
if (is_str_type(c, fi.tnode)) {
emit_line("\tMOVQ\t");
emit_disp_reg((fi.foff + 8): i64, "BX");
emit_line(", CX\n");
emit_line("\tMOVQ\t");
emit_disp_reg(fi.foff: i64, "BX");
emit_line(", AX\n");
emit_line("\tMOVQ\tCX, BX\n");
} else {
let op: str = field_load_op(fi);
emit_line("\t");
emit_line(op);
emit_line("\t");
emit_disp_reg(fi.foff: i64, "BX");
emit_line(", AX\n");
};
return;
};
fi = fi.finext;
};
};
};
};
// Direct struct local: field load at off+foff.
if (lkind == N_TNAME) {
let sname: str = tn.str;
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
// str field: load both halves so chained
// `.ptr` / `.len` see (AX=ptr, BX=len).
if (is_str_type(c, fi.tnode)) {
emit_line("\tMOVQ\t");
emit_off((lc.off + fi.foff): i64);
emit_line("(BP), AX\n");
emit_line("\tMOVQ\t");
emit_off((lc.off + fi.foff + 8): i64);
emit_line("(BP), BX\n");
} else {
let op: str = field_load_op(fi);
emit_line("\t");
emit_line(op);
emit_line("\t");
emit_off((lc.off + fi.foff): i64);
emit_line("(BP), AX\n");
};
return;
};
fi = fi.finext;
};
};
};
// Array pseudo-fields: `.ptr` is the array's
// address (LEAQ); `.len` is the static element
// count (immediate).
if (lkind == N_TARRAY) {
if (streq(fld, "ptr")) {
emit_line("\tLEAQ\t");
emit_off(lc.off: i64);
emit_line("(BP), AX\n");
return;
};
if (streq(fld, "len")) {
let len_n: *node = tn.rhs;
let alen: i64 = 0i64;
if (len_n != nil) {
if (len_n.kind == N_INTLIT) { alen = len_n.uval: i64; };
};
emit_line("\tMOVQ\t$");
emit_int(alen);
emit_line(", AX\n");
return;
};
};
// str/slice pseudo-fields .ptr/.len/.cap on a
// direct local: load at slot+delta.
let delta: i32 = -1;
if (streq(fld, "ptr")) { delta = 0; };
if (streq(fld, "len")) { delta = 8; };
if (streq(fld, "cap")) { delta = 16; };
if (delta >= 0) {
// Pointer to str/slice (`*[]u8`, `*str`):
// deref, then load at delta within the
// pointed-to header. C cgen does the same.
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
let inner_kind: i32 = -1;
if (inner != nil) { inner_kind = inner.kind; };
let inner_str: bool = false;
if (inner_kind == N_TNAME) {
if (streq(inner.str, "str")) { inner_str = true; };
};
if (inner_kind == N_TSLICE) { inner_str = true; };
if (inner_str) {
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
emit_line("\tMOVQ\t");
emit_disp_reg(delta: i64, "BX");
emit_line(", AX\n");
return;
};
};
emit_line("\tMOVQ\t");
emit_off((lc.off + delta): i64);
emit_line("(BP), AX\n");
return;
};
};
};
};
// Module-qualified value reference: `mod.name` where `mod`
// is N_IDENT bound as SK_USE and the leaf isn't a local.
// Treat as a SB symbol — `MOVQ leaf(SB), AX`. Same fallback
// the C cgen takes when bt is NULL/ty_err.
if (lhs != nil) {
if (lhs.kind == N_IDENT) {
emit_line("\tMOVQ\t");
emit_line(fld);
emit_line("(SB), AX\n");
return;
};
};
// Non-ident base pseudo-field: e.g. `"abc".ptr` / `"abc".len`.
// Evaluate the str-producing expression — that leaves
// (AX=ptr, BX=len). Then `.ptr` returns AX as is; `.len`
// shuffles BX→AX. Mirrors what C cgen does (it just evaluates
// the literal and picks the half it wants).
if (streq(fld, "ptr")) { cgexpr(c, lhs); return; };
if (streq(fld, "len")) {
cgexpr(c, lhs);
emit_line("\tMOVQ\tBX, AX\n");
return;
};
// Chained struct-field-via-ptr-via-ptr access:
// r.sym.val where r: *lrel, .sym: *lsym, .val: u64
// Inner DOT (`r.sym`) returns a *struct (a pointer-to-struct
// field). Outer DOT dereferences and reads `val`. Without this
// path the cgen falls through and AX retains whatever the
// inner expression left there — typically the *struct pointer
// itself, so reads silently get the pointer value instead of
// the field. (Showed up porting w6l/pass.ww.)
if (lhs != nil) {
if (lhs.kind == N_DOT) {
let inner_t: *node = dot_inner_struct_ptr(c, lhs);
if (inner_t != nil) {
let sname: str = inner_t.str;
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
if (streq(fi.fname, fld)) {
cgexpr(c, lhs); // AX = ptr to inner struct
let lop: str = field_load_op(fi);
// str field: load both halves.
if (is_str_type(c, fi.tnode)) {
emit_line("\tMOVQ\t");
emit_disp_reg((fi.foff + 8): i64, "AX");
emit_line(", BX\n");
emit_line("\tMOVQ\t");
emit_disp_reg(fi.foff: i64, "AX");
emit_line(", AX\n");
return;
};
emit_line("\t");
emit_line(lop);
emit_line("\t");
emit_disp_reg(fi.foff: i64, "AX");
emit_line(", AX\n");
return;
};
fi = fi.finext;
};
};
};
};
};
return;
};
if (k == N_UN) {
// Match C cgen ordering: evaluate operand first (load into AX),
// then apply the unary op. AMP / STAR override AX with the
// address / deref. The wasted load before AMP keeps our asm
// byte-identical to the C version.
cgexpr(c, n.lhs);
if (n.op == TK_MINUS) { emit_line("\tNEGQ\tAX\n"); return; };
if (n.op == TK_TILDE) { emit_line("\tNOTQ\tAX\n"); return; };
if (n.op == TK_STAR) { emit_line("\tMOVQ\t(AX), AX\n"); return; };
if (n.op == TK_AMP) {
let opnd: *node = n.lhs;
if (opnd != nil) {
if (opnd.kind == N_IDENT) {
let nm: str = opnd.str;
let off: i32 = local_find(c, nm);
if (off != 0) {
emit_line("\tLEAQ\t");
emit_off(off: i64);
emit_line("(BP), AX\n");
return;
};
};
};
return;
};
if (n.op == TK_NOT) {
let t: str = mklabel(c, "tt");
let e: str = mklabel(c, "te");
emit_line("\tCMPQ\t$0, AX\n");
emit_line("\tJE\t"); emit_line(t); emit_line("\n");
emit_line("\tMOVQ\t$0, AX\n");
emit_line("\tJMP\t"); emit_line(e); emit_line("\n");
emit_label(t);
emit_line("\tMOVQ\t$1, AX\n");
emit_label(e);
return;
};
return;
};
if (k == N_BIN) {
let unsignd: bool = node_isunsigned(c, n.lhs);
if (!unsignd) { unsignd = node_isunsigned(c, n.rhs); };
cgexpr(c, n.rhs);
emit_line("\tPUSHQ\tAX\n");
cgexpr(c, n.lhs);
emit_line("\tPOPQ\tBX\n");
if (n.op == TK_PLUS) { emit_line("\tADDQ\tBX, AX\n"); return; };
if (n.op == TK_MINUS) { emit_line("\tSUBQ\tBX, AX\n"); return; };
if (n.op == TK_STAR) { emit_line("\tIMULQ\tBX, AX\n"); return; };
if (n.op == TK_SLASH) {
emit_line("\tMOVQ\t$0, DX\n");
if (unsignd) { emit_line("\tDIVQ\tBX\n"); }
else { emit_line("\tIDIVQ\tBX\n"); };
return;
};
if (n.op == TK_PERCENT) {
emit_line("\tMOVQ\t$0, DX\n");
if (unsignd) { emit_line("\tDIVQ\tBX\n"); }
else { emit_line("\tIDIVQ\tBX\n"); };
emit_line("\tMOVQ\tDX, AX\n");
return;
};
if (n.op == TK_AMP) { emit_line("\tANDQ\tBX, AX\n"); return; };
if (n.op == TK_PIPE) { emit_line("\tORQ\tBX, AX\n"); return; };
if (n.op == TK_CARET) { emit_line("\tXORQ\tBX, AX\n"); return; };
if (n.op == TK_LSHIFT) {
emit_line("\tMOVQ\tBX, CX\n");
emit_line("\tSHLQ\tCX, AX\n");
return;
};
if (n.op == TK_RSHIFT) {
emit_line("\tMOVQ\tBX, CX\n");
emit_line("\tSHRQ\tCX, AX\n");
return;
};
if (n.op == TK_AND) { emit_line("\tANDQ\tBX, AX\n"); return; };
if (n.op == TK_OR) { emit_line("\tORQ\tBX, AX\n"); return; };
// Comparison: emit CMPQ, jump on signed/unsigned variant,
// materialise 0/1 in AX. Same shape as the C cgen.
let is_cmp: bool = false;
let jcc: str = "";
if (n.op == TK_EQ) { is_cmp = true; jcc = "JE"; };
if (n.op == TK_NEQ) { is_cmp = true; jcc = "JNE"; };
if (n.op == TK_LT) { is_cmp = true; if (unsignd) { jcc = "JB"; } else { jcc = "JL"; }; };
if (n.op == TK_LE) { is_cmp = true; if (unsignd) { jcc = "JBE"; } else { jcc = "JLE"; }; };
if (n.op == TK_GT) { is_cmp = true; if (unsignd) { jcc = "JA"; } else { jcc = "JG"; }; };
if (n.op == TK_GE) { is_cmp = true; if (unsignd) { jcc = "JAE"; } else { jcc = "JGE"; }; };
if (is_cmp) {
let t: str = mklabel(c, "ct");
let e: str = mklabel(c, "ce");
emit_line("\tCMPQ\tBX, AX\n");
emit_line("\t"); emit_line(jcc); emit_line("\t"); emit_line(t); emit_line("\n");
emit_line("\tMOVQ\t$0, AX\n");
emit_line("\tJMP\t"); emit_line(e); emit_line("\n");
emit_label(t);
emit_line("\tMOVQ\t$1, AX\n");
emit_label(e);
return;
};
return;
};
if (k == N_CALL) {
let nargs: i32 = push_args_rev(c, n.list);
let i: i32 = 0;
for (i < nargs) {
emit_line("\tPOPQ\t");
emit_line(argreg_name(i));
emit_line("\n");
i += 1;
};
let callee: *node = n.lhs;
let callee_name: str;
callee_name.ptr = nil; callee_name.len = 0;
// Detect fn-pointer field call: `w.emit(args)` where `w` is
// a struct local and `emit` is an N_TFN field. Load the
// field value into AX and CALL through it. Also detect a
// bare `fp(args)` where `fp` is a local holding a function
// pointer — mirror C cgen's localfind dispatch (commit
// 635818e). Without this the call emits `CALL fp(SB)` and
// the linker rightly fails.
let is_fnptr_call: bool = false;
if (callee != nil) {
if (callee.kind == N_IDENT) {
let cn: str = callee.str;
if (local_find_node(c, cn) != nil) {
is_fnptr_call = true;
};
};
if (callee.kind == N_DOT) {
let base: *node = callee.lhs;
let fld: str = callee.str;
if (base != nil) {
if (base.kind == N_IDENT) {
let bn: str = base.str;
let lc: *local = local_find_node(c, bn);
if (lc != nil) {
let tn: *node = lc.tnode;
if (tn != nil) {
let lkind: i32 = tn.kind;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (lkind == N_TNAME) { sname = tn.str; };
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
if (inner != nil) {
if (inner.kind == N_TNAME) { sname = inner.str; };
};
};
if (sname.len > 0) {
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
let ft: *node = fi.tnode;
if (ft != nil) {
if (ft.kind == N_TFN) {
is_fnptr_call = true;
};
};
fi = nil;
} else {
fi = fi.finext;
};
};
};
};
};
};
};
};
};
};
if (is_fnptr_call) {
// Load fn-ptr field value into AX; CALL AX. We emit the
// load AFTER the args have been popped (so AX/BX/etc
// don't get clobbered by the field load before the pops).
// `popped args` left DI/SI/etc set; AX is free.
cgexpr(c, callee);
emit_line("\tCALL\tAX\n");
} else {
emit_line("\tCALL\t");
if (callee != nil) {
if (callee.kind == N_IDENT) {
callee_name = callee.str;
let resolved: str = ffi_resolve(c, callee_name);
os.write(1, resolved.ptr, resolved.len: u64);
} else { if (callee.kind == N_DOT) {
callee_name = callee.str;
let resolved: str = ffi_resolve(c, callee_name);
os.write(1, resolved.ptr, resolved.len: u64);
};};
};
emit_line("(SB)\n");
};
// SysV returns 16-byte aggregates in (AX, DX). Our str
// convention is (AX, BX), so shuffle for str-returning calls.
if (callee_name.len > 0) {
let rt: *node = fnret_lookup(c, callee_name);
if (is_str_type(c, rt)) {
emit_line("\tMOVQ\tDX, BX\n");
};
};
return;
};
if (k == N_ASSIGN) {
let lhs: *node = n.lhs;
// `*p = v` — deref-assign. Element width comes from the
// pointer's declared type. Mirrors C cgen: eval rhs (AX,
// and BX if str), push, eval pointer, pop value, store.
// We default to MOVQ (8B) since most fixtures use it; for
// `*bool` / `*u8` / `*i32` we narrow via the local's tnode.
if (lhs != nil) {
if (lhs.kind == N_UN) {
if (lhs.op == TK_STAR) {
if (n.op == TK_ASSIGN) {
let inner: *node = lhs.lhs;
let elem_str: bool = false;
let store_op: str = "MOVQ";
if (inner != nil) {
if (inner.kind == N_IDENT) {
let lc: *local = local_find_node(c, inner.str);
if (lc != nil) {
let tn: *node = lc.tnode;
if (tn != nil) {
if (tn.kind == N_TPTR) {
let pe: *node = tn.lhs;
if (pe != nil) {
if (pe.kind == N_TNAME) {
if (streq(pe.str, "str")) { elem_str = true; }
else {
let ps: i32 = prim_size(pe.str);
if (ps == 1) { store_op = "MOVB"; }
else { if (ps == 4) { store_op = "MOVL"; }; };
};
};
};
};
};
};
};
};
cgexpr(c, n.rhs);
// Push order matches C cgen
// (cmd/w6c/cgen.c:1033-1041): PUSHQ AX
// (ptr) first, then PUSHQ BX (len) if
// str, so the pop sequence is POP CX
// (len) → POP AX (ptr) → MOVQ AX,
// (BX) → MOVQ CX, 8(BX).
emit_line("\tPUSHQ\tAX\n");
if (elem_str) { emit_line("\tPUSHQ\tBX\n"); };
cgexpr(c, inner);
emit_line("\tMOVQ\tAX, BX\n");
if (elem_str) {
emit_line("\tPOPQ\tCX\n");
emit_line("\tPOPQ\tAX\n");
emit_line("\tMOVQ\tAX, (BX)\n");
emit_line("\tMOVQ\tCX, 8(BX)\n");
return;
};
emit_line("\tPOPQ\tAX\n");
emit_line("\t");
emit_line(store_op);
emit_line("\tAX, (BX)\n");
return;
};
};
};
};
// Array/slice/ptr index store: `arr[i] = v;`. Element size
// from base.tnode picks MOVB vs MOVQ.
if (lhs != nil) {
if (lhs.kind == N_INDEX) {
if (n.op == TK_ASSIGN) {
let base: *node = lhs.lhs;
let idx: *node = lhs.rhs;
let esz: i32 = 8;
let base_local: *local = nil;
if (base != nil) {
if (base.kind == N_IDENT) {
let bn: str = base.str;
base_local = local_find_node(c, bn);
if (base_local != nil) {
esz = elem_size_of(base_local.tnode);
};
} else { if (base.kind == N_DOT) {
esz = index_base_esz(c, base);
};};
};
cgexpr(c, n.rhs); // value → AX
if (esz == 16) { emit_line("\tPUSHQ\tBX\n"); };
emit_line("\tPUSHQ\tAX\n");
cgexpr(c, idx); // idx → AX
if (esz > 1) {
emit_line("\tMOVQ\t$");
emit_int(esz: i64);
emit_line(", CX\n");
emit_line("\tIMULQ\tCX, AX\n");
};
emit_line("\tPUSHQ\tAX\n"); // scaled idx
if (base_local != nil) {
let tn: *node = base_local.tnode;
let is_array: bool = false;
if (tn != nil) { if (tn.kind == N_TARRAY) { is_array = true; }; };
if (is_array) {
emit_line("\tLEAQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), BX\n");
} else {
emit_line("\tMOVQ\t");
emit_off(base_local.off: i64);
emit_line("(BP), BX\n");
};
} else {
cgexpr(c, base);
emit_line("\tMOVQ\tAX, BX\n");
};
emit_line("\tPOPQ\tAX\n"); // scaled idx
emit_line("\tADDQ\tAX, BX\n");
emit_line("\tPOPQ\tAX\n"); // value
if (esz == 16) {
emit_line("\tMOVQ\tAX, (BX)\n");
emit_line("\tPOPQ\tCX\n");
emit_line("\tMOVQ\tCX, 8(BX)\n");
return;
};
if (esz == 1) { emit_line("\tMOVB\tAX, (BX)\n"); }
else { emit_line("\tMOVQ\tAX, (BX)\n"); };
return;
};
};
};
// Struct/ptr-to-struct field assignment: `s.f = expr;` or
// `p.f = expr;`. Only plain `=` is wired (compound on field
// is rare and not yet needed by our fixtures).
if (lhs != nil) {
if (lhs.kind == N_DOT) {
let base: *node = lhs.lhs;
let fld: str = lhs.str;
if (base != nil) {
if (base.kind == N_IDENT) {
let bn: str = base.str;
let lc: *local = local_find_node(c, bn);
if (lc != nil) {
let tn: *node = lc.tnode;
let lkind: i32 = -1;
if (tn != nil) { lkind = tn.kind; };
// Pointer-to-struct: deref then store.
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (inner != nil) {
if (inner.kind == N_TNAME) { sname = inner.str; };
};
if (sname.len > 0) {
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
if (n.op != TK_ASSIGN) {
// compound: load current value
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
let lop: str = field_load_op(fi);
emit_line("\t");
emit_line(lop);
emit_line("\t");
emit_disp_reg(fi.foff: i64, "BX");
emit_line(", BX\n");
emit_line("\tPUSHQ\tBX\n");
};
cgexpr(c, n.rhs);
if (n.op != TK_ASSIGN) {
emit_line("\tPOPQ\tBX\n");
// PLUSEQ is commutative; MINUSEQ
// needs lhs - rhs (BX is old lhs,
// AX is rhs).
if (n.op == TK_PLUSEQ) { emit_line("\tADDQ\tBX, AX\n"); };
if (n.op == TK_MINUSEQ) {
emit_line("\tSUBQ\tAX, BX\n");
emit_line("\tMOVQ\tBX, AX\n");
};
};
// str field via *struct: rhs left
// (AX=ptr, BX=len). Use CX as the
// address scratch so we don't clobber
// the len half before storing it.
if (n.op == TK_ASSIGN) {
if (is_str_type(c, fi.tnode)) {
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), CX\n");
emit_line("\tMOVQ\tAX, ");
emit_disp_reg(fi.foff: i64, "CX");
emit_line("\n");
emit_line("\tMOVQ\tBX, ");
emit_disp_reg((fi.foff + 8): i64, "CX");
emit_line("\n");
return;
};
};
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
let sop: str = field_store_op(fi);
emit_line("\t");
emit_line(sop);
emit_line("\tAX, ");
emit_disp_reg(fi.foff: i64, "BX");
emit_line("\n");
return;
};
fi = fi.finext;
};
};
};
};
// Direct struct local: store at off+foff.
if (lkind == N_TNAME) {
let sname: str = tn.str;
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fld)) {
cgexpr(c, n.rhs);
let sop: str = field_store_op(fi);
emit_line("\t");
emit_line(sop);
emit_line("\tAX, ");
emit_off((lc.off + fi.foff): i64);
emit_line("(BP)\n");
return;
};
fi = fi.finext;
};
};
};
// str/slice pseudo-field assignment.
let delta: i32 = -1;
if (streq(fld, "ptr")) { delta = 0; };
if (streq(fld, "len")) { delta = 8; };
if (streq(fld, "cap")) { delta = 16; };
if (delta >= 0) {
if (lkind == N_TPTR) {
let inner: *node = tn.lhs;
let inner_kind: i32 = -1;
if (inner != nil) { inner_kind = inner.kind; };
let inner_str: bool = false;
if (inner_kind == N_TNAME) {
if (streq(inner.str, "str")) { inner_str = true; };
};
if (inner_kind == N_TSLICE) { inner_str = true; };
if (inner_str) {
if (n.op != TK_ASSIGN) {
// Compound on `(*str|*slice).field`: load
// current → push → eval rhs → combine → store.
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
emit_line("\tMOVQ\t");
emit_disp_reg(delta: i64, "BX");
emit_line(", BX\n");
emit_line("\tPUSHQ\tBX\n");
cgexpr(c, n.rhs);
emit_line("\tPOPQ\tBX\n");
// PLUSEQ is commutative; MINUSEQ
// needs lhs - rhs.
if (n.op == TK_PLUSEQ) { emit_line("\tADDQ\tBX, AX\n"); };
if (n.op == TK_MINUSEQ) {
emit_line("\tSUBQ\tAX, BX\n");
emit_line("\tMOVQ\tBX, AX\n");
};
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
emit_line("\tMOVQ\tAX, ");
emit_disp_reg(delta: i64, "BX");
emit_line("\n");
return;
};
cgexpr(c, n.rhs);
emit_line("\tMOVQ\t");
emit_off(lc.off: i64);
emit_line("(BP), BX\n");
emit_line("\tMOVQ\tAX, ");
emit_disp_reg(delta: i64, "BX");
emit_line("\n");
return;
};
};
cgexpr(c, n.rhs);
emit_line("\tMOVQ\tAX, ");
emit_off((lc.off + delta): i64);
emit_line("(BP)\n");
return;
};
};
};
};
};
};
// Local-ident target — plain `=` and the simple compound
// forms (+= -= *= /=); other compounds fall back to
// "evaluate rhs, replace". Mirrors C cgen's IDENT-assign path.
if (lhs != nil) {
if (lhs.kind == N_IDENT) {
let nm: str = lhs.str;
let off: i32 = local_find(c, nm);
if (off == 0) { return; };
// Detect str-typed local — assignment must store both
// halves (AX=ptr at +0, BX=len at +8).
let lc_str: bool = false;
let lcn: *local = local_find_node(c, nm);
if (lcn != nil) { lc_str = is_str_type(c, lcn.tnode); };
cgexpr(c, n.rhs);
if (n.op == TK_ASSIGN) {
emit_line("\tMOVQ\tAX, ");
emit_off(off: i64);
emit_line("(BP)\n");
if (lc_str) {
emit_line("\tMOVQ\tBX, ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
};
return;
};
if (n.op == TK_PLUSEQ) {
emit_line("\tADDQ\tAX, ");
emit_off(off: i64);
emit_line("(BP)\n");
return;
};
if (n.op == TK_MINUSEQ) {
emit_line("\tSUBQ\tAX, ");
emit_off(off: i64);
emit_line("(BP)\n");
return;
};
// Generic compound: load → combine in BX → store.
emit_line("\tMOVQ\t");
emit_off(off: i64);
emit_line("(BP), BX\n");
if (n.op == TK_STAREQ) { emit_line("\tIMULQ\tAX, BX\n"); };
if (n.op == TK_AMPEQ) { emit_line("\tANDQ\tAX, BX\n"); };
if (n.op == TK_PIPEEQ) { emit_line("\tORQ\tAX, BX\n"); };
if (n.op == TK_CARETEQ) { emit_line("\tXORQ\tAX, BX\n"); };
if (n.op == TK_LSHIFTEQ) {
emit_line("\tMOVQ\tAX, CX\n");
emit_line("\tSHLQ\tCX, BX\n");
};
if (n.op == TK_RSHIFTEQ) {
emit_line("\tMOVQ\tAX, CX\n");
emit_line("\tSHRQ\tCX, BX\n");
};
emit_line("\tMOVQ\tBX, ");
emit_off(off: i64);
emit_line("(BP)\n");
return;
};
};
return;
};
};
// ---- type-driven slot sizing ----------------------------------------
fn struct_lookup(c: *cgen, name: str) *struct_info = {
let s: *struct_info = c.structs;
for (s != nil) {
let sn: str = s.sname;
if (streq(sn, name)) { return s; };
s = s.sinext;
};
return nil;
};
// prim_size — size in bytes of a primitive type name (or 0 if not
// recognised as a primitive — the caller falls back to other paths).
fn prim_size(name: str) i32 = {
if (streq(name, "u8")) { return 1; };
if (streq(name, "i8")) { return 1; };
if (streq(name, "bool")) { return 1; };
if (streq(name, "u16")) { return 2; };
if (streq(name, "i16")) { return 2; };
if (streq(name, "u32")) { return 4; };
if (streq(name, "i32")) { return 4; };
if (streq(name, "f32")) { return 4; };
if (streq(name, "u64")) { return 8; };
if (streq(name, "i64")) { return 8; };
if (streq(name, "uint")) { return 8; };
if (streq(name, "int")) { return 8; };
if (streq(name, "uintptr")) { return 8; };
if (streq(name, "f64")) { return 8; };
if (streq(name, "rune")) { return 4; };
if (streq(name, "void")) { return 0; };
return 0;
};
fn slot_size(c: *cgen, typ_n: *node) i32 = {
if (typ_n == nil) { return 8; };
let k: i32 = typ_n.kind;
if (k == N_TPTR) { return 8; };
if (k == N_TFN) { return 8; };
if (k == N_TCHAN) { return 8; };
if (k == N_TSLICE) { return 24; };
if (k == N_TTUPLE) { return 16; };
if (k == N_TTAGGED){ return 24; };
if (k == N_TNAME) {
let nm: str = typ_n.str;
if (streq(nm, "str")) { return 16; };
let ps: i32 = prim_size(nm);
if (ps > 0) {
// Pad to 8 for stack slots — matches C cgen which spills
// every primitive into an 8-byte slot.
return 8;
};
// Named struct lookup.
let si: *struct_info = struct_lookup(c, nm);
if (si != nil) { return si.tot_size; };
return 8;
};
if (k == N_TARRAY) {
let len_n: *node = typ_n.rhs;
let elem_n: *node = typ_n.lhs;
let elen: i64 = 1i64;
if (len_n != nil) {
if (len_n.kind == N_INTLIT) { elen = len_n.uval: i64; };
};
let esz: i32 = 8;
if (elem_n != nil) {
if (elem_n.kind == N_TNAME) {
let en: str = elem_n.str;
let ps: i32 = prim_size(en);
if (ps > 0) { esz = ps; };
};
};
return (esz: i64 * elen): i32;
};
if (k == N_TSTRUCT) {
// Inline anonymous struct — sum of field sizes.
let f: *node = typ_n.list;
let total: i32 = 0;
for (f != nil) {
if (f.kind == N_TFIELD) {
total += slot_size(c, f.lhs);
};
f = f.next;
};
return total;
};
return 8;
};
// register_struct — compute field offsets + total size for a struct
// type-decl, store in c.structs. Field type sizes use the same
// slot_size logic (with primitives kept at their natural width — we
// only round to 8 for stack slots, not struct interiors).
fn field_size(c: *cgen, tnode: *node) i32 = {
if (tnode == nil) { return 8; };
let k: i32 = tnode.kind;
if (k == N_TNAME) {
let nm: str = tnode.str;
if (streq(nm, "str")) { return 16; };
let ps: i32 = prim_size(nm);
if (ps > 0) { return ps; };
let si: *struct_info = struct_lookup(c, nm);
if (si != nil) { return si.tot_size; };
return 8;
};
if (k == N_TPTR) { return 8; };
if (k == N_TSLICE) { return 24; };
if (k == N_TARRAY) {
// Same shape as slot_size's TARRAY branch.
let len_n: *node = tnode.rhs;
let elem_n: *node = tnode.lhs;
let elen: i64 = 1i64;
if (len_n != nil) {
if (len_n.kind == N_INTLIT) { elen = len_n.uval: i64; };
};
let esz: i32 = field_size(c, elem_n);
return (esz: i64 * elen): i32;
};
return 8;
};
fn register_struct(c: *cgen, name: str, tstruct: *node) void = {
let si: *struct_info = amalloc(c.a, 64u64): *struct_info;
si.sname = name;
si.fields = nil;
si.tot_size = 0;
let head: *field_info = nil;
let tail: *field_info = nil;
let off: i32 = 0;
let f: *node = tstruct.list;
for (f != nil) {
if (f.kind == N_TFIELD) {
let sz: i32 = field_size(c, f.lhs);
// Align to 8 for any field >= 4 bytes (matches our other
// cgen choices). i8/u8/bool may sit on odd byte offsets;
// the C cgen does similar best-effort packing.
let aln: i32 = 1;
if (sz >= 8) { aln = 8; }
else { if (sz >= 4) { aln = 4; }
else { if (sz >= 2) { aln = 2; }; }; };
if ((off & (aln - 1)) != 0) {
off = (off + aln - 1) & ~(aln - 1);
};
let fi: *field_info = amalloc(c.a, 48u64): *field_info;
fi.fname = f.str;
fi.foff = off;
fi.fsz = sz;
fi.tnode = f.lhs;
if (head == nil) { head = fi; tail = fi; }
else { tail.finext = fi; tail = fi; };
off += sz;
};
f = f.next;
};
// Round total to 8 for stack-slot use.
if ((off & 7) != 0) { off = (off + 7) & ~7; };
si.fields = head;
si.tot_size = off;
si.sinext = c.structs;
c.structs = si;
};
fn collect_structs(c: *cgen, file: *node) void = {
c.structs = nil;
if (file == nil) { return; };
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_TYPEDECL) {
let body: *node = d.lhs;
if (body != nil) {
if (body.kind == N_TSTRUCT) {
register_struct(c, d.str, body);
};
};
};
d = d.next;
};
};
// ---- frame pre-scan --------------------------------------------------
//
// Recursively walks the body to count every local `let`. Each gets a
// slot sized by slot_size(typ); 8-byte default. Match-bindings + for-
// init lets count too. Params are added by the cgfn driver.
fn scan_locals(c: *cgen, n: *node) i32 = {
if (n == nil) { return 0; };
let total: i32 = 0;
if (n.kind == N_LET) {
// Match local_add's rounding: < 8 bumps to 8, then 8-align.
// scan_locals must agree with local_add or the prologue
// SUBQ undersizes the frame and lets overflow into the
// caller's stack — corrupting whatever's at -frameSize..-1
// of the caller. Same-name re-declarations share the first
// slot (see scan_seen_mark / local_add).
if (!scan_seen_mark(c, n.str)) {
let sz: i32 = slot_size(c, n.lhs);
if (sz < 8) { sz = 8; };
if ((sz & 7) != 0) { sz = (sz + 7) & ~7; };
total += sz;
};
};
// Match-arm binding (`case let v: T => ...`) gets a slot too.
// Crucially we do NOT dedup these against c.locals: C cgen
// handles a match as an expression with a by-value locals copy,
// so two separate matches in the same function each allocate
// their `v`/`e` slots fresh. Treating these as deduped would
// shrink the frame below what local_add then bumps it to.
if (n.kind == N_MCASE) {
let bn: str = n.str;
if (bn.len > 0) {
let pat: *node = n.lhs;
if (pat != nil) {
if (is_str_type(c, pat)) { total += 16; }
else { total += 8; };
};
};
};
if (n.lhs != nil) { total += scan_locals(c, n.lhs); };
if (n.rhs != nil) { total += scan_locals(c, n.rhs); };
if (n.cond != nil) { total += scan_locals(c, n.cond); };
if (n.body != nil) { total += scan_locals(c, n.body); };
if (n.els != nil) { total += scan_locals(c, n.els); };
if (n.list != nil) {
let m: *node = n.list;
for (m != nil) {
total += scan_locals(c, m);
m = m.next;
};
};
return total;
};
// ---- statement cgen --------------------------------------------------
fn cgstmt(c: *cgen, n: *node) void = {
if (n == nil) { return; };
let k: i32 = n.kind;
if (k == N_BLOCK) {
let s: *node = n.list;
for (s != nil) {
cgstmt(c, s);
s = s.next;
};
return;
};
if (k == N_RETURN) {
let rhs: *node = n.lhs;
if (rhs != nil) {
// Tuple return `return a, b;` — pack as (AX=v0, DX=v1).
// Matches C cgen: evaluate v1 first (PUSHQ), then v0
// into AX, then POPQ DX. End state: AX = v0, DX = v1.
if (rhs.kind == N_TUPLE) {
let v: *node = rhs.list;
if (v != nil) {
let v2: *node = v.next;
if (v2 != nil) {
cgexpr(c, v2);
emit_line("\tPUSHQ\tAX\n");
cgexpr(c, v);
emit_line("\tPOPQ\tDX\n");
} else {
cgexpr(c, v);
};
};
emit_line("\tMOVQ\tBP, SP\n");
emit_line("\tPOPQ\tBP\n");
emit_line("\tRET\n");
c.last_was_return = 1;
return;
};
// Tagged-union return: pack as (AX=tag, DX=value0, CX=value1).
// For str variant, cgexpr leaves (AX=ptr, BX=len), so we
// shuffle DX←AX (ptr) and CX←BX (len), then load tag.
// For other variants, cgexpr leaves AX, shuffle DX←AX.
if (is_tagged_type(c.fn_ret)) {
cgexpr(c, rhs);
let idx: i32 = tagged_variant_index(c, c.fn_ret, rhs);
if (node_isstr(c, rhs)) {
emit_line("\tMOVQ\tBX, CX\n");
emit_line("\tMOVQ\tAX, DX\n");
} else {
emit_line("\tMOVQ\tAX, DX\n");
};
emit_line("\tMOVQ\t$");
if (idx < 0) { idx = 0; };
emit_int(idx: i64);
emit_line(", AX\n");
emit_line("\tMOVQ\tBP, SP\n");
emit_line("\tPOPQ\tBP\n");
emit_line("\tRET\n");
c.last_was_return = 1;
return;
};
cgexpr(c, rhs);
} else {
// Bare `return;` in a void fn — zero AX so the caller
// sees a deterministic value (matches C cgen, which
// always falls through to `cgexpr_int(c, 0)`).
emit_line("\tMOVQ\t$0, AX\n");
};
// SysV: 16-byte aggregates (str, 2-tuple) return in (AX, DX).
// cgexpr leaves str in (AX, BX); shuffle BX→DX.
if (is_str_type(c, c.fn_ret)) {
emit_line("\tMOVQ\tBX, DX\n");
};
emit_line("\tMOVQ\tBP, SP\n");
emit_line("\tPOPQ\tBP\n");
emit_line("\tRET\n");
c.last_was_return = 1;
return;
};
if (k == N_EXPRSTMT) {
if (n.lhs != nil) { cgexpr(c, n.lhs); };
c.last_was_return = 0;
return;
};
if (k == N_LET) {
let nm: str = n.str;
let sz: i32 = slot_size(c, n.lhs);
let off: i32 = local_add(c, nm, sz, n.lhs);
if (n.rhs != nil) {
let rhs: *node = n.rhs;
// Tagged-union init: `let r: (T | E) = expr;`.
// - If rhs is a CALL to a fn returning tagged-union,
// the result is already in (AX=tag, DX=v0, CX=v1);
// just spill all three.
// - Otherwise rhs is a bare variant value: pack tag +
// value(s).
if (is_tagged_type(n.lhs)) {
let rhs_returns_tagged: bool = false;
if (rhs.kind == N_CALL) {
let callee: *node = rhs.lhs;
if (callee != nil) {
let callee_name: str;
callee_name.ptr = nil; callee_name.len = 0;
if (callee.kind == N_IDENT) { callee_name = callee.str; };
if (callee.kind == N_DOT) { callee_name = callee.str; };
if (callee_name.len > 0) {
let rt: *node = fnret_lookup(c, callee_name);
if (is_tagged_type(rt)) { rhs_returns_tagged = true; };
};
};
};
cgexpr(c, rhs);
if (rhs_returns_tagged) {
emit_line("\tMOVQ\tAX, ");
emit_off(off: i64);
emit_line("(BP)\n");
emit_line("\tMOVQ\tDX, ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
emit_line("\tMOVQ\tCX, ");
emit_off((off + 16): i64);
emit_line("(BP)\n");
c.last_was_return = 0;
return;
};
let tag_idx: i32 = tagged_variant_index(c, n.lhs, rhs);
if (tag_idx < 0) { tag_idx = 0; };
if (node_isstr(c, rhs)) {
emit_line("\tMOVQ\tAX, ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
emit_line("\tMOVQ\tBX, ");
emit_off((off + 16): i64);
emit_line("(BP)\n");
} else {
emit_line("\tMOVQ\tAX, ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
};
emit_line("\tMOVQ\t$");
emit_int(tag_idx: i64);
emit_line(", ");
emit_off(off: i64);
emit_line("(BP)\n");
c.last_was_return = 0;
return;
};
// Struct literal init: `let p: point = point{x=..., y=...};`.
// For each field in the lit, evaluate its value and store at
// the field's offset within the slot. Field-name → offset
// from the struct registry.
if (rhs.kind == N_STRUCTLIT) {
let trefn: *node = rhs.lhs;
let sname: str;
sname.ptr = nil; sname.len = 0;
if (trefn != nil) {
if (trefn.kind == N_IDENT) { sname = trefn.str; }
else { if (trefn.kind == N_TNAME) { sname = trefn.str; }; };
};
let si: *struct_info = struct_lookup(c, sname);
if (si != nil) {
let field_node: *node = rhs.list;
for (field_node != nil) {
if (field_node.kind == N_FIELD) {
let fname: str = field_node.str;
let fi: *field_info = si.fields;
for (fi != nil) {
let fn_: str = fi.fname;
if (streq(fn_, fname)) {
cgexpr(c, field_node.lhs);
let sop: str = field_store_op(fi);
emit_line("\t");
emit_line(sop);
emit_line("\tAX, ");
emit_off((off + fi.foff): i64);
emit_line("(BP)\n");
fi = nil;
} else {
fi = fi.finext;
};
};
};
field_node = field_node.next;
};
c.last_was_return = 0;
return;
};
};
cgexpr(c, rhs);
emit_line("\tMOVQ\tAX, ");
emit_off(off: i64);
emit_line("(BP)\n");
// str init: cgexpr also leaves len in BX; store both.
if (sz == 16) {
emit_line("\tMOVQ\tBX, ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
};
// slice init: ptr/len/cap in AX/BX/CX.
if (sz == 24) {
emit_line("\tMOVQ\tBX, ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
emit_line("\tMOVQ\tCX, ");
emit_off((off + 16): i64);
emit_line("(BP)\n");
};
} else {
// Bare `let x: T;` with no initializer. C cgen
// (cmd/w6c/cgen.c:2181-2183) zero-inits only when
// the underlying type's natural size is 8 — pointers,
// i64/u64, function pointers, ints. Structs/arrays/
// slices/strings/tagged/tuples are left for per-field
// writes. ww's slot_size pads struct slots up to 8,
// so we can't just check sz == 8: walk the type AST
// directly to make the same call.
if (type_is_8byte_primitive(c, n.lhs)) {
emit_line("\tMOVQ\t$0, ");
emit_off(off: i64);
emit_line("(BP)\n");
};
};
c.last_was_return = 0;
return;
};
if (k == N_IF) {
let els: str = mklabel(c, "else");
let endl: str = mklabel(c, "end");
cgexpr(c, n.cond);
emit_line("\tCMPQ\t$0, AX\n");
emit_line("\tJE\t");
if (n.els != nil) { emit_line(els); }
else { emit_line(endl); };
emit_line("\n");
if (n.body != nil) { cgstmt(c, n.body); };
if (n.els != nil) {
emit_line("\tJMP\t"); emit_line(endl); emit_line("\n");
emit_label(els);
cgstmt(c, n.els);
};
emit_label(endl);
c.last_was_return = 0;
return;
};
if (k == N_FOR) {
// Match C cgen's label scheme: <fn>_loop_N for the top,
// <fn>_endloop_N for the post-body merge. No separate cont
// label when there's no post-expression.
let topl: str = mklabel(c, "loop");
let endl: str = mklabel(c, "endloop");
if (n.lhs != nil) { cgstmt(c, n.lhs); };
emit_label(topl);
if (n.cond != nil) {
cgexpr(c, n.cond);
emit_line("\tCMPQ\t$0, AX\n");
emit_line("\tJE\t"); emit_line(endl); emit_line("\n");
};
c.loop_end_buf[c.loop_top] = endl;
c.loop_cont_buf[c.loop_top] = topl;
c.loop_top += 1;
if (n.body != nil) { cgstmt(c, n.body); };
c.loop_top -= 1;
if (n.rhs != nil) { cgexpr(c, n.rhs); };
emit_line("\tJMP\t"); emit_line(topl); emit_line("\n");
emit_label(endl);
c.last_was_return = 0;
return;
};
// Tuple-destructure assign: `a, b = call();`. The call's tuple
// return lands in (AX, DX); push DX to free it, store AX into
// the first lvalue, then pop DX into the second. Mirrors
// cmd/w6c/cgen.c:2424-2440. Lvalues beyond two are dropped (same
// as C — no fixture uses >2 today).
if (k == N_MASSIGN) {
if (n.rhs != nil) { cgexpr(c, n.rhs); };
emit_line("\tPUSHQ\tDX\n");
let l0: *node = n.list;
let l1: *node = nil;
if (l0 != nil) { l1 = l0.next; };
if (l0 != nil) {
if (l0.kind == N_IDENT) {
let off: i32 = local_find(c, l0.str);
if (off != 0) {
emit_line("\tMOVQ\tAX, ");
emit_off(off: i64);
emit_line("(BP)\n");
};
};
};
emit_line("\tPOPQ\tDX\n");
if (l1 != nil) {
if (l1.kind == N_IDENT) {
let off: i32 = local_find(c, l1.str);
if (off != 0) {
emit_line("\tMOVQ\tDX, ");
emit_off(off: i64);
emit_line("(BP)\n");
};
};
};
c.last_was_return = 0;
return;
};
if (k == N_BREAK) {
if (c.loop_top > 0) {
let lbl: str = c.loop_end_buf[c.loop_top - 1];
emit_line("\tJMP\t"); emit_line(lbl); emit_line("\n");
};
c.last_was_return = 0;
return;
};
if (k == N_CONTINUE) {
if (c.loop_top > 0) {
let lbl: str = c.loop_cont_buf[c.loop_top - 1];
emit_line("\tJMP\t"); emit_line(lbl); emit_line("\n");
};
c.last_was_return = 0;
return;
};
c.last_was_return = 0;
};
// ---- function-level cgen ---------------------------------------------
// is_str_type — true when the type expr resolves (through any
// `type X = str;` aliases) to `str`. Takes *cgen so it can walk the
// alias chain registered at file load.
fn is_str_type_raw(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind == N_TNAME) {
let nm: str = t.str;
if (streq(nm, "str")) { return true; };
};
return false;
};
fn is_str_type(c: *cgen, t: *node) bool = {
if (is_str_type_raw(t)) { return true; };
if (c == nil) { return false; };
let r: *node = resolve_type(c, t);
return is_str_type_raw(r);
};
fn is_slice_type_raw(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind == N_TSLICE) { return true; };
return false;
};
fn is_slice_type(c: *cgen, t: *node) bool = {
if (is_slice_type_raw(t)) { return true; };
if (c == nil) { return false; };
let r: *node = resolve_type(c, t);
return is_slice_type_raw(r);
};
fn is_tagged_type(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind == N_TTAGGED) { return true; };
return false;
};
// rhs_target_name — for a returned value, what's its declared (or
// surface-inferred) type name? `expr: T` casts dictate T directly;
// bare strlit/intlit fall back to a primitive name.
fn rhs_target_name(c: *cgen, rhs: *node) str = {
let nm: str;
nm.ptr = nil; nm.len = 0;
if (rhs == nil) { return nm; };
if (rhs.kind == N_CAST) {
let t: *node = rhs.rhs;
if (t != nil) {
if (t.kind == N_TNAME) { return t.str; };
};
return nm;
};
if (rhs.kind == N_STRLIT) { return "str"; };
if (rhs.kind == N_IDENT) {
let lc: *local = local_find_node(c, rhs.str);
if (lc != nil) {
let tn: *node = lc.tnode;
if (tn != nil) {
if (tn.kind == N_TNAME) { return tn.str; };
};
};
};
return nm;
};
// tagged_variant_index — given the tagged-union type expr and the
// returned value's surface type, find the matching variant's 0-based
// index. Compare by exact type name first; if no match, fall back to
// "any str-shape variant matches an str-typed value".
fn tagged_variant_index(c: *cgen, tagged: *node, rhs: *node) i32 = {
if (tagged == nil) { return -1; };
if (rhs == nil) { return -1; };
let want_name: str = rhs_target_name(c, rhs);
if (want_name.len > 0) {
let v: *node = tagged.list;
let idx: i32 = 0;
for (v != nil) {
if (v.kind == N_TNAME) {
if (streq(v.str, want_name)) { return idx; };
};
v = v.next;
idx += 1;
};
};
// Fallback: by str-shape (resolves aliases).
let want_str: bool = node_isstr(c, rhs);
let v: *node = tagged.list;
let idx: i32 = 0;
for (v != nil) {
let v_is_str: bool = false;
if (v.kind == N_TNAME) {
if (is_str_type(c, v)) { v_is_str = true; };
};
if (v_is_str == want_str) { return idx; };
v = v.next;
idx += 1;
};
return -1;
};
fn cgfn_params(c: *cgen, params: *node) void = {
let p: *node = params;
let idx: i32 = 0;
for (p != nil) {
if (p.kind == N_PARAM) {
let nm: str = p.str;
if (is_tagged_type(p.lhs)) {
// tagged-union param: passed in 3 regs (tag, v0, v1),
// 24-byte slot.
let off: i32 = local_add(c, nm, 24, p.lhs);
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off(off: i64);
emit_line("(BP)\n");
idx += 1;
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
idx += 1;
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off((off + 16): i64);
emit_line("(BP)\n");
idx += 1;
} else { if (is_slice_type(c, p.lhs)) {
// slice param: 3 regs (ptr, len, cap), 24-byte slot.
let off: i32 = local_add(c, nm, 24, p.lhs);
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off(off: i64);
emit_line("(BP)\n");
idx += 1;
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
idx += 1;
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off((off + 16): i64);
emit_line("(BP)\n");
idx += 1;
} else { if (is_str_type(c, p.lhs)) {
// str param: passed in two regs (ptr, len).
// Slot is 16 bytes; ptr at off+0, len at off+8.
let off: i32 = local_add(c, nm, 16, p.lhs);
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off(off: i64);
emit_line("(BP)\n");
idx += 1;
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off((off + 8): i64);
emit_line("(BP)\n");
idx += 1;
} else {
let off: i32 = local_add(c, nm, 8, p.lhs);
emit_line("\tMOVQ\t");
emit_line(argreg_name(idx));
emit_line(", ");
emit_off(off: i64);
emit_line("(BP)\n");
idx += 1;
};};};
};
p = p.next;
};
};
fn cgfn(c: *cgen, fn_: *node) void = {
cgen_init(c, c.a);
c.fn_name = fn_.str;
c.fn_ret = fn_.lhs;
emit_line("TEXT ");
let nm: str = fn_.str;
os.write(1, nm.ptr, nm.len: u64);
emit_line(",$");
// Pre-scan total frame: 24 bytes per slice param, 16 per str
// param, 8 per other param, plus per-let from scan_locals.
// Seed c.locals with param-name stubs so scan_locals dedups a
// re-declared `let <name>` in the body against the param's
// slot (matches C cgen). Stubs get cleared before emission.
let scan_p: *node = fn_.list;
let frame: i32 = 0;
for (scan_p != nil) {
if (scan_p.kind == N_PARAM) {
if (is_tagged_type(scan_p.lhs)) { frame += 24; }
else { if (is_slice_type(c, scan_p.lhs)) { frame += 24; }
else { if (is_str_type(c, scan_p.lhs)) { frame += 16; }
else { frame += 8; }; }; };
scan_seen_mark(c, scan_p.str);
};
scan_p = scan_p.next;
};
if (fn_.body != nil) { frame += scan_locals(c, fn_.body); };
// Drop the stubs so emission rebuilds c.locals with real offsets.
c.locals = nil;
if ((frame & 15) != 0) {
frame = (frame + 15) & ~15;
};
emit_int(frame: i64);
emit_line("\n");
emit_line("\tPUSHQ\tBP\n");
emit_line("\tMOVQ\tSP, BP\n");
emit_line("\tSUBQ\t$");
emit_int(frame: i64);
emit_line(", SP\n");
cgfn_params(c, fn_.list);
c.last_was_return = 0;
if (fn_.body != nil) { cgstmt(c, fn_.body); };
if (c.last_was_return == 0) {
// Zero AX before the fall-through return — matches C cgen,
// which always emits this so void-returning fns don't leak
// a stale callee value to their caller.
emit_line("\tMOVQ\t$0, AX\n");
emit_line("\tMOVQ\tBP, SP\n");
emit_line("\tPOPQ\tBP\n");
emit_line("\tRET\n");
};
};
// ---- file-level entry ------------------------------------------------
export fn cg_file(c: *cgen, file: *node) void = {
if (file == nil) { return; };
c.strlits = nil;
c.strlit_seq = 0;
collect_aliases(c, file);
collect_structs(c, file);
collect_defs(c, file);
collect_fnrets(c, file);
ffi_collect(c, file);
let d: *node = file.list;
for (d != nil) {
if (d.kind == N_FNDECL) {
if (d.body != nil) {
cgfn(c, d);
};
};
d = d.next;
};
emit_data_section(c);
emit_def_constants(c, file);
};