Hojun-Cho
6fd0160c0f
Closes the remaining tagged-union gaps after the prior two commits:
1. Tagged element in an array/slice (cstage). N_INDEX load now reads
slot words into AX/DX/CX, matching the tagged-return ABI so match
/ call-arg / let-init paths consume `arr[i]` uniformly. N_INDEX
store routes through a scratch slot + cg_widen_tagged_store +
byte-copy to &arr[i], so the full widening machinery (scalar /
str / struct payload / tagged subset / nullable fold) lights up
for element writes too.
2. Selfhost mirror — the cgen widen helpers (struct payload,
tagged-subset, spread-flatten) C cgen has had for two commits
finally land in selfhost:
cgwidentaggedstore — single writer for nullable / tagged ident /
tagged via AX:DX:CX / struct (lit + ident) /
str / scalar source shapes.
cgwidentagremap — CMPQ-chain tag remap for variant-subset.
rhsstructpayload — struct-name predicate; filters `!void` /
`!i32` aliases that share N_STRUCTLIT shape
but aren't structs.
rhstaggedident,
rhstaggedabicall — source-shape predicates.
flatvariantidx — spread-aware variant index lookup. Walks
`(...inner | T)` entries by resolving the
alias and inlining the inner's variants so
wwstage's tag order matches the check.c
flattening cstage does at type resolution.
cglet tagged init, cgassign tagged-ident reassign, cgreturn struct
/ subset payload, pushargsrev struct payload, cgindex tagged
element load, cgassign N_INDEX tagged element store all delegate
to these. cgmatch picks up scrutt from N_INDEX bases (element
type) and uses flatvariantidx for case dispatch.
3. Selfhost frame accounting: scanlocals reserves a 24B @tagscr slot
when the body contains a tagged-arr store, a struct-payload
tagged return, or a struct-payload call arg — dedup'd via
scanseenmark so multiple sites share one slot. N_LET stubs now
carry tnode so walk-time type checks see the array element type.
slotsize TARRAY learned to size tagged / struct / ptr / aliased
elements (was 8B-default for anything not N_TNAME-primitive,
undersizing tagged-element arrays).
Scalar / str call-arg widening keeps its direct-push fast path
(no scratch), so wwstage's asm on selfhost source remains
byte-identical to cstage's — 993/995 still pass.
700_e2e: 9 new rows — scalar/str/struct/subset/nullable variants in
arrays and slices, plus pass-arg / let-init / return / match shapes.
1091 lines
30 KiB
Plaintext
1091 lines
30 KiB
Plaintext
// selfhost/cmd/wcc/cgenstmt.ww — split out of cgen.ww.
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//
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// cgstmt is a thin dispatcher over n.kind; each branch defers to a
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// per-kind helper: cgblock, cgreturn, cgexprstmt, cglet, cgif, cgfor,
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// cgmassign, cgbreak, cgcontinue.
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//
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// The expression generator (cgexpr) lives in cgenexpr.ww; the
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// foundation (types, emit primitives, collect* tables, FFI/module
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// maps) lives in cgen.ww.
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use os;
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use mem;
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use ast;
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use tok;
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use typ;
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use sym;
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use strconv;
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// ---- statement cgen --------------------------------------------------
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fn cgstmt(c: *cgen, n: *node) void = {
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if (n == nil) { return; };
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let k: nkind = n.kind;
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if (k == nkind.N_BLOCK) { cgblock(c, n); return; };
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if (k == nkind.N_RETURN) { cgreturn(c, n); return; };
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if (k == nkind.N_EXPRSTMT) { cgexprstmt(c, n); return; };
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if (k == nkind.N_LET) { cglet(c, n); return; };
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if (k == nkind.N_IF) { cgif(c, n); return; };
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if (k == nkind.N_FOR) { cgfor(c, n); return; };
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if (k == nkind.N_FORRANGE) { cgforrange(c, n); return; };
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if (k == nkind.N_SWITCH) { cgswitch(c, n); return; };
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if (k == nkind.N_MASSIGN) { cgmassign(c, n); return; };
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if (k == nkind.N_MLET) { cgmlet(c, n); return; };
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if (k == nkind.N_BREAK) { cgbreak(c, n); return; };
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if (k == nkind.N_CONTINUE) { cgcontinue(c, n); return; };
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if (k == nkind.N_YIELD) { cgyield(c, n); return; };
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if (k == nkind.N_DEFER) {
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if (c.defertop < DEFER_MAX) {
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c.deferbuf[c.defertop] = n.lhs;
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c.defertop += 1;
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};
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return;
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};
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c.lastwasreturn = 0;
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};
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fn cgyield(c: *cgen, n: *node) void = {
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// Evaluate the value into AX (and BX for str), then JMP to the
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// enclosing match's end label. Falls through silently if there
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// is no active match — should be a checker error eventually.
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if (n.lhs != nil) { cgexpr(c, n.lhs); };
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if (c.yieldtop > 0) {
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let tgt: str = c.yieldbuf[c.yieldtop - 1];
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emitline("\tJMP\t");
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emitline(tgt);
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emitline("\n");
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};
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c.lastwasreturn = 0;
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return;
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};
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fn cgblock(c: *cgen, n: *node) void = {
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let s: *node = n.list;
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for (s != nil) {
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cgstmt(c, s);
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s = s.next;
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};
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return;
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};
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// rundefers — emit cgexpr for every queued defer in LIFO order.
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// Called from cgreturn and the cgfn implicit-return path.
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fn rundefers(c: *cgen) void = {
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let i: i32 = c.defertop - 1;
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for (i >= 0) {
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cgexpr(c, c.deferbuf[i]);
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i -= 1;
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};
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return;
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};
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fn cgreturn(c: *cgen, n: *node) void = {
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rundefers(c);
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let rhs: *node = n.lhs;
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if (rhs != nil) {
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// Tuple return `return a, b;`:
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// (scalar, scalar) — AX = v0, DX = v1.
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// (scalar, str) / (str, scalar) — AX = scalar elem,
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// DX = str.ptr, CX = str.len.
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// 24B convention mirrors the tagged-union return below; receive
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// sites destructure off the same regs regardless of position.
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if (rhs.kind == nkind.N_TUPLE) {
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let v: *node = rhs.list;
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if (v != nil) {
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let v2: *node = v.next;
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if (v2 != nil) {
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let v0_is_str: bool = nodeisstr(c, v);
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let v1_is_str: bool = nodeisstr(c, v2);
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if ((v0_is_str || v1_is_str) && !(v0_is_str && v1_is_str)) {
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let strn: *node = v;
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let scaln: *node = v2;
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if (v1_is_str) { strn = v2; scaln = v; };
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cgexpr(c, scaln);
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emitline("\tPUSHQ\tAX\n");
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cgexpr(c, strn);
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emitline("\tMOVQ\tBX, CX\n");
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emitline("\tMOVQ\tAX, DX\n");
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emitline("\tPOPQ\tAX\n");
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} else {
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cgexpr(c, v2);
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emitline("\tPUSHQ\tAX\n");
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cgexpr(c, v);
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emitline("\tPOPQ\tDX\n");
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};
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} else {
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cgexpr(c, v);
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};
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};
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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// Tagged-union return: pack as (AX=tag, DX=value0, CX=value1).
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// For str variant, cgexpr leaves (AX=ptr, BX=len), so we
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// shuffle DX←AX (ptr) and CX←BX (len), then load tag.
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// For other variants, cgexpr leaves AX, shuffle DX←AX.
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// Nullable folded `(*T | void)`: just one word; AX is
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// already the pointer (or 0). No shuffle, no tag.
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if (istaggedtype(c, c.fnret)) {
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// Forwarding a fallible call: `return f();` where f
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// also returns a tagged union. The result is already
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// in (AX=tag, DX=v0, CX=v1) — no shuffle, no tag.
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// Mirrors the rhsreturnstagged path in cglet and the
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// !type_istagged guard in C cgen's N_RETURN.
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let forwardtagged: bool = false;
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if (rhs.kind == nkind.N_CALL) {
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let callee: *node = rhs.lhs;
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if (callee != nil) {
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let calleename: str;
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calleename.ptr = nil; calleename.len = 0;
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if (callee.kind == nkind.N_IDENT) { calleename = callee.str; };
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if (callee.kind == nkind.N_DOT) { calleename = callee.str; };
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if (calleename.len > 0) {
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let rt: *node = fnretlookup(c, calleename);
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if (istaggedtype(c, rt)) { forwardtagged = true; };
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};
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};
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};
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// Struct payload or tagged-subset return — materialise
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// the widened value in scratch via cgwidentaggedstore
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// (handles tag remap and zero pad), then load AX/DX/CX
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// from the slot.
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let needswiden: bool = false;
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if (!isnullabletype(c.fnret)) {
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if (!forwardtagged) {
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let sname: str = rhsstructpayload(c, rhs);
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if (sname.len > 0) { needswiden = true; };
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if (rhstaggedident(c, rhs) != nil) {
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needswiden = true;
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};
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};
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};
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if (needswiden) {
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let rsz: i32 = slotsize(c, c.fnret);
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let scroff: i32 = localadd(c, "@tagscr",
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24, nil);
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emitline("\tXORQ\tAX, AX\n");
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let zz: i32 = 0;
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for (zz < rsz) {
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emitline("\tMOVQ\tAX, ");
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emitoff((scroff + zz): i64);
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emitline("(BP)\n");
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zz += 8;
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};
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cgwidentaggedstore(c, c.fnret, rhs, scroff,
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rsz);
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emitline("\tMOVQ\t");
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emitoff(scroff: i64);
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emitline("(BP), AX\n");
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if (rsz > 8) {
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emitline("\tMOVQ\t");
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emitoff((scroff + 8): i64);
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emitline("(BP), DX\n");
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};
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if (rsz > 16) {
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emitline("\tMOVQ\t");
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emitoff((scroff + 16): i64);
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emitline("(BP), CX\n");
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};
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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cgexpr(c, rhs);
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if (isnullabletype(c.fnret)) {
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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if (forwardtagged) {
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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let idx: i32 = taggedvariantindex(c, c.fnret, rhs);
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if (nodeisstr(c, rhs)) {
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emitline("\tMOVQ\tBX, CX\n");
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emitline("\tMOVQ\tAX, DX\n");
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} else {
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emitline("\tMOVQ\tAX, DX\n");
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};
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emitline("\tMOVQ\t$");
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if (idx < 0) { idx = 0; };
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emitint(idx: i64);
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emitline(", AX\n");
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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cgexpr(c, rhs);
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} else {
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// Bare `return;` from a tagged-union-returning fn is
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// the void variant: emit its tag. Payload is undefined
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// (void has size 0). Otherwise zero AX for determinism.
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if (istaggedtype(c, c.fnret)) {
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if (isnullabletype(c.fnret)) {
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// null = void variant; AX = 0.
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emitline("\tMOVQ\t$0, AX\n");
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} else {
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let idx: i32 = voidvariantindex(c.fnret);
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if (idx < 0) { idx = 0; };
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emitline("\tMOVQ\t$");
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emitint(idx: i64);
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emitline(", AX\n");
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};
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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emitline("\tMOVQ\t$0, AX\n");
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};
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// SysV: 16-byte aggregates (str, 2-tuple) return in (AX, DX).
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// cgexpr leaves str in (AX, BX); shuffle BX→DX.
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if (isstrtype(c, c.fnret)) {
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emitline("\tMOVQ\tBX, DX\n");
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};
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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c.lastwasreturn = 1;
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return;
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};
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fn cgexprstmt(c: *cgen, n: *node) void = {
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if (n.lhs != nil) { cgexpr(c, n.lhs); };
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c.lastwasreturn = 0;
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return;
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};
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fn cglet(c: *cgen, n: *node) void = {
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let nm: str = n.str;
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let sz: i32 = letslotsize(c, n);
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// `let x = f()?` has no annotation but the cgen's struct-field
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// paths need a tnode to dispatch off. Infer from f's tagged
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// success variant — see inferletcalltype.
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let tn: *node = n.lhs;
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if (tn == nil) { tn = inferletcalltype(c, n.rhs); };
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let off: i32 = localadd(c, nm, sz, tn);
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if (n.rhs != nil) {
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let rhs: *node = n.rhs;
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// Tagged-union init: delegate to cgwidentaggedstore, which
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// handles nullable fold, tagged source (ident or AX/DX/CX
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// ABI call), struct payload (literal/ident), str payload,
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// scalar payload — with tag remap for tagged-subset widening.
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if (istaggedtype(c, tn)) {
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cgwidentaggedstore(c, tn, rhs, off, sz);
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c.lastwasreturn = 0;
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return;
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};
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// 24B tuple init for `let t: (scalar, str) = call()` /
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// `let t: (str, scalar) = call()`. Per the AX:DX:CX return
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// convention: AX = scalar elem, DX = str.ptr, CX = str.len.
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// Layout is positional, so we route each register to the
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// slot dictated by element type, not by AX/DX position.
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if (n.lhs != nil) {
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if (n.lhs.kind == nkind.N_TTUPLE) {
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let p0: *node = n.lhs.list;
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let p1: *node = nil;
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if (p0 != nil) { p1 = p0.next; };
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let s0_is_str: bool = isstrtyperaw(p0);
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let s1_is_str: bool = isstrtyperaw(p1);
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if (p0 != nil) {
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if (p1 != nil) {
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if (s0_is_str != s1_is_str) {
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cgexpr(c, rhs);
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if (s0_is_str) {
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emitline("\tMOVQ\tDX, ");
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emitoff(off: i64);
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emitline("(BP)\n");
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emitline("\tMOVQ\tCX, ");
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emitoff((off + 8): i64);
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emitline("(BP)\n");
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emitline("\tMOVQ\tAX, ");
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emitoff((off + 16): i64);
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emitline("(BP)\n");
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} else {
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emitline("\tMOVQ\tAX, ");
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emitoff(off: i64);
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emitline("(BP)\n");
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emitline("\tMOVQ\tDX, ");
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emitoff((off + 8): i64);
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emitline("(BP)\n");
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emitline("\tMOVQ\tCX, ");
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emitoff((off + 16): i64);
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emitline("(BP)\n");
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};
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c.lastwasreturn = 0;
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return;
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};
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};
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};
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};
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};
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// Array literal init: `let xs: [N]T = [a, b, c];` (or [_]T).
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// Walk elements in declaration order, store each at off + i*esz
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// using the right width for the element type. Trailing `...`
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// after the last value (an nkind.N_FIELD with str=="...") fills the
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// remaining slots up to the declared length with that value.
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if (rhs.kind == nkind.N_ARRLIT) {
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let elemn: *node = n.lhs.lhs;
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let esz: i32 = 8;
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if (elemn != nil) {
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if (elemn.kind == nkind.N_TNAME) {
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let ps: i32 = primsize(elemn.str);
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if (ps > 0) { esz = ps; };
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};
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};
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let mop: str = "MOVQ";
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if (esz == 1) { mop = "MOVB"; }
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else { if (esz == 4) { mop = "MOVL"; }; };
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let idx: i32 = 0;
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let repeat: bool = false;
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let e: *node = rhs.list;
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for (e != nil) {
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if (e.kind == nkind.N_FIELD) {
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if (streq(e.str, "...")) {
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repeat = true;
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e = nil;
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} else {
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cgexpr(c, e);
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emitline("\t");
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emitline(mop);
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emitline("\tAX, ");
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emitoff((off + idx * esz): i64);
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emitline("(BP)\n");
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idx += 1;
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e = e.next;
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};
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} else {
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cgexpr(c, e);
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emitline("\t");
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emitline(mop);
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emitline("\tAX, ");
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emitoff((off + idx * esz): i64);
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emitline("(BP)\n");
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idx += 1;
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e = e.next;
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};
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};
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// AX still holds the last stored value; fill remaining
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// slots up to the declared length with it.
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if (repeat) {
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let total: i32 = idx;
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if (n.lhs != nil) {
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if (n.lhs.kind == nkind.N_TARRAY) {
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if (n.lhs.rhs != nil) {
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if (n.lhs.rhs.kind == nkind.N_INTLIT) {
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total = n.lhs.rhs.uval: i32;
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};
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};
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};
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};
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for (idx < total) {
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emitline("\t");
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emitline(mop);
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emitline("\tAX, ");
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emitoff((off + idx * esz): i64);
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emitline("(BP)\n");
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idx += 1;
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};
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};
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c.lastwasreturn = 0;
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return;
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};
|
|
// 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. When the literal carries
|
|
// op == tkind.TK_ELLIPSIS (autofill marker from the parser), the
|
|
// entire slot is zero-filled first so unmentioned fields
|
|
// read as 0.
|
|
if (rhs.kind == nkind.N_STRUCTLIT) {
|
|
let trefn: *node = rhs.lhs;
|
|
let sname: str;
|
|
sname.ptr = nil; sname.len = 0;
|
|
if (trefn != nil) {
|
|
if (trefn.kind == nkind.N_IDENT) { sname = trefn.str; }
|
|
else { if (trefn.kind == nkind.N_TNAME) { sname = trefn.str; }; };
|
|
};
|
|
let si: *structinfo = structlookup(c, sname);
|
|
if (si != nil) {
|
|
if (rhs.op == tkind.TK_ELLIPSIS) {
|
|
let total: i32 = si.totsize;
|
|
emitline("\tXORQ\tAX, AX\n");
|
|
let zi: i32 = 0;
|
|
for (zi + 8 <= total) {
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff((off + zi): i64);
|
|
emitline("(BP)\n");
|
|
zi += 8;
|
|
};
|
|
for (zi + 4 <= total) {
|
|
emitline("\tMOVL\tAX, ");
|
|
emitoff((off + zi): i64);
|
|
emitline("(BP)\n");
|
|
zi += 4;
|
|
};
|
|
for (zi < total) {
|
|
emitline("\tMOVB\tAX, ");
|
|
emitoff((off + zi): i64);
|
|
emitline("(BP)\n");
|
|
zi += 1;
|
|
};
|
|
};
|
|
let fieldnode: *node = rhs.list;
|
|
for (fieldnode != nil) {
|
|
if (fieldnode.kind == nkind.N_FIELD) {
|
|
let fname: str = fieldnode.str;
|
|
let fi: *fieldinfo = si.fields;
|
|
for (fi != nil) {
|
|
let fn_: str = fi.fname;
|
|
if (streq(fn_, fname)) {
|
|
cgexpr(c, fieldnode.lhs);
|
|
// f64/f32 struct-literal field init: cgexpr left
|
|
// the value in X0, store via MOVSD/MOVSS.
|
|
if (isfloattype(c, fi.tnode)) {
|
|
let mov: str = "MOVSD";
|
|
if (isf32type(c, fi.tnode)) { mov = "MOVSS"; };
|
|
emitline("\t");
|
|
emitline(mov);
|
|
emitline("\tX0, ");
|
|
emitoff((off + fi.foff): i64);
|
|
emitline("(BP)\n");
|
|
fi = nil;
|
|
} else {
|
|
let sop: str = fieldstoreop(fi);
|
|
emitline("\t");
|
|
emitline(sop);
|
|
emitline("\tAX, ");
|
|
emitoff((off + fi.foff): i64);
|
|
emitline("(BP)\n");
|
|
fi = nil;
|
|
};
|
|
} else {
|
|
fi = fi.finext;
|
|
};
|
|
};
|
|
};
|
|
fieldnode = fieldnode.next;
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
};
|
|
cgexpr(c, rhs);
|
|
// Float local: cgexpr leaves the value in X0. Spill via
|
|
// MOVSS (f32, 4B) or MOVSD (f64, 8B).
|
|
if (isfloattype(c, n.lhs)) {
|
|
let mov: str = "MOVSD";
|
|
if (isf32type(c, n.lhs)) { mov = "MOVSS"; };
|
|
emitline("\t");
|
|
emitline(mov);
|
|
emitline("\tX0, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
// str init: cgexpr also leaves len in BX; store both.
|
|
if (sz == 16) {
|
|
emitline("\tMOVQ\tBX, ");
|
|
emitoff((off + 8): i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
// slice init: ptr/len/cap in AX/BX/CX.
|
|
if (sz == 24) {
|
|
emitline("\tMOVQ\tBX, ");
|
|
emitoff((off + 8): i64);
|
|
emitline("(BP)\n");
|
|
emitline("\tMOVQ\tCX, ");
|
|
emitoff((off + 16): i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
} else {
|
|
// Bare `let x: T;` with no initializer. C cgen
|
|
// (cmd/w6c/cgen.c:3317) zero-inits whenever the raw type size
|
|
// is 8: scalar primitives, pointers, fn/chan handles, plus 8B
|
|
// composites like `[8]bool`, `[2]i32`, `[4]i16`, `[1]i64`.
|
|
// Larger composites and `[N]T` with size != 8 are left for
|
|
// per-field writes.
|
|
if (typeis8byteprimitive(c, n.lhs)) {
|
|
emitline("\tMOVQ\t$0, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
fn cgif(c: *cgen, n: *node) void = {
|
|
let els: str = mklabel(c, "else");
|
|
let endl: str = mklabel(c, "end");
|
|
cgexpr(c, n.cond);
|
|
emitline("\tCMPQ\t$0, AX\n");
|
|
emitline("\tJE\t");
|
|
if (n.els != nil) { emitline(els); }
|
|
else { emitline(endl); };
|
|
emitline("\n");
|
|
if (n.body != nil) { cgstmt(c, n.body); };
|
|
if (n.els != nil) {
|
|
emitline("\tJMP\t"); emitline(endl); emitline("\n");
|
|
emitlabel(els);
|
|
cgstmt(c, n.els);
|
|
};
|
|
emitlabel(endl);
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
fn cgfor(c: *cgen, n: *node) void = {
|
|
// 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");
|
|
// `else` runs at natural cond-false exit; break skips it. When
|
|
// present, branch the cond-fail edge to a separate natural_exit
|
|
// label so the else body sits between it and the break target.
|
|
let naturall: str = endl;
|
|
if (n.els != nil) { naturall = mklabel(c, "elseloop"); };
|
|
|
|
if (n.lhs != nil) { cgstmt(c, n.lhs); };
|
|
|
|
emitlabel(topl);
|
|
if (n.cond != nil) {
|
|
cgexpr(c, n.cond);
|
|
emitline("\tCMPQ\t$0, AX\n");
|
|
emitline("\tJE\t"); emitline(naturall); emitline("\n");
|
|
};
|
|
|
|
c.loopendbuf[c.looptop] = endl;
|
|
c.loopcontbuf[c.looptop] = topl;
|
|
c.looptop += 1;
|
|
|
|
if (n.body != nil) { cgstmt(c, n.body); };
|
|
|
|
c.looptop -= 1;
|
|
|
|
if (n.rhs != nil) { cgexpr(c, n.rhs); };
|
|
emitline("\tJMP\t"); emitline(topl); emitline("\n");
|
|
if (n.els != nil) {
|
|
emitlabel(naturall);
|
|
cgstmt(c, n.els);
|
|
};
|
|
emitlabel(endl);
|
|
c.lastwasreturn = 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).
|
|
fn cgmassign(c: *cgen, n: *node) void = {
|
|
if (n.rhs != nil) { cgexpr(c, n.rhs); };
|
|
emitline("\tPUSHQ\tDX\n");
|
|
let l0: *node = n.list;
|
|
let l1: *node = nil;
|
|
if (l0 != nil) { l1 = l0.next; };
|
|
if (l0 != nil) {
|
|
if (l0.kind == nkind.N_IDENT) {
|
|
let off: i32 = localfind(c, l0.str);
|
|
if (off != 0) {
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
};
|
|
};
|
|
emitline("\tPOPQ\tDX\n");
|
|
if (l1 != nil) {
|
|
if (l1.kind == nkind.N_IDENT) {
|
|
let off: i32 = localfind(c, l1.str);
|
|
if (off != 0) {
|
|
emitline("\tMOVQ\tDX, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
};
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
// Multi-let from a tuple-returning call: `let n, s = call();` or
|
|
// `let (n, s) = call();`. wwstage has no checker, so each binding's
|
|
// type is taken from its explicit annotation (l.lhs) when present
|
|
// or inferred from the called fn's return-type tuple element.
|
|
//
|
|
// Per the AX:DX:CX return convention (mirrors C cgen nkind.N_MLET):
|
|
// (scalar, scalar) — AX → l0, DX → l1.
|
|
// (scalar, str) — AX → scalar slot, (DX, CX) → str slot
|
|
// as (.ptr, .len). Position-agnostic — the
|
|
// regs are routed by element type, not by AX/DX.
|
|
fn cgmlet(c: *cgen, n: *node) void = {
|
|
let rhs: *node = n.rhs;
|
|
if (rhs == nil) { return; };
|
|
|
|
let p0t: *node = nil;
|
|
let p1t: *node = nil;
|
|
if (rhs.kind == nkind.N_CALL) {
|
|
let callee: *node = rhs.lhs;
|
|
if (callee != nil) {
|
|
let cnm: str;
|
|
cnm.ptr = nil; cnm.len = 0;
|
|
if (callee.kind == nkind.N_IDENT) { cnm = callee.str; };
|
|
if (callee.kind == nkind.N_DOT) { cnm = callee.str; };
|
|
if (cnm.len > 0) {
|
|
let rt: *node = fnretlookup(c, cnm);
|
|
if (rt != nil) {
|
|
if (rt.kind == nkind.N_TTUPLE) {
|
|
p0t = rt.list;
|
|
if (p0t != nil) { p1t = p0t.next; };
|
|
};
|
|
};
|
|
};
|
|
};
|
|
};
|
|
|
|
let l0: *node = n.list;
|
|
let l1: *node = nil;
|
|
if (l0 != nil) { l1 = l0.next; };
|
|
|
|
let t0: *node = nil;
|
|
let t1: *node = nil;
|
|
if (l0 != nil) { t0 = l0.lhs; };
|
|
if (l1 != nil) { t1 = l1.lhs; };
|
|
if (t0 == nil) { t0 = p0t; };
|
|
if (t1 == nil) { t1 = p1t; };
|
|
|
|
let s0_is_str: bool = isstrtyperaw(t0);
|
|
let s1_is_str: bool = isstrtyperaw(t1);
|
|
|
|
cgexpr(c, rhs);
|
|
|
|
if (l0 != nil) {
|
|
if (l1 != nil) {
|
|
if (s0_is_str != s1_is_str) {
|
|
let sz0: i32 = 8;
|
|
let sz1: i32 = 8;
|
|
if (s0_is_str) { sz0 = 16; };
|
|
if (s1_is_str) { sz1 = 16; };
|
|
let off0: i32 = localadd(c, l0.str, sz0, t0);
|
|
let off1: i32 = localadd(c, l1.str, sz1, t1);
|
|
if (s0_is_str) {
|
|
emitline("\tMOVQ\tDX, ");
|
|
emitoff(off0: i64);
|
|
emitline("(BP)\n");
|
|
emitline("\tMOVQ\tCX, ");
|
|
emitoff((off0 + 8): i64);
|
|
emitline("(BP)\n");
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(off1: i64);
|
|
emitline("(BP)\n");
|
|
} else {
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(off0: i64);
|
|
emitline("(BP)\n");
|
|
emitline("\tMOVQ\tDX, ");
|
|
emitoff(off1: i64);
|
|
emitline("(BP)\n");
|
|
emitline("\tMOVQ\tCX, ");
|
|
emitoff((off1 + 8): i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
};
|
|
};
|
|
|
|
if (l0 != nil) {
|
|
let off: i32 = localadd(c, l0.str, 8, t0);
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
if (l1 != nil) {
|
|
let off: i32 = localadd(c, l1.str, 8, t1);
|
|
emitline("\tMOVQ\tDX, ");
|
|
emitoff(off: i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
// paramfieldsize — raw byte size of a tuple-field type. Mirrors the
|
|
// `tp->type->size` read in C cgen N_FORRANGE: 1 for i8/u8/bool, 4 for
|
|
// i32/u32, 8 for i64/u64/*T/fn/slice-elt, 16 for str, default 8.
|
|
fn paramfieldsize(t: *node) i32 = {
|
|
if (t == nil) { return 8; };
|
|
let k: nkind = t.kind;
|
|
if (k == nkind.N_TPTR) { return 8; };
|
|
if (k == nkind.N_TFN) { return 8; };
|
|
if (k == nkind.N_TCHAN) { return 8; };
|
|
if (k == nkind.N_TNAME) {
|
|
let nm: str = t.str;
|
|
if (streq(nm, "str")) { return 16; };
|
|
let ps: i32 = primsize(nm);
|
|
if (ps > 0) { return ps; };
|
|
};
|
|
return 8;
|
|
};
|
|
|
|
// paramissigned — does this primitive type need sign-extending on a
|
|
// narrow (4B) load? Mirrors C cgen's `binds[b].signed_field` flag.
|
|
fn paramissigned(t: *node) bool = {
|
|
if (t == nil) { return false; };
|
|
if (t.kind != nkind.N_TNAME) { return false; };
|
|
let nm: str = t.str;
|
|
if (streq(nm, "i8")) { return true; };
|
|
if (streq(nm, "i16")) { return true; };
|
|
if (streq(nm, "i32")) { return true; };
|
|
return false;
|
|
};
|
|
|
|
// cgforrange — lower `for (let x .. slice) body` (and the tuple-
|
|
// destructure cousin `for (let (a, b) .. slice) body`). The body is
|
|
// wrapped in a counted loop driven by stack-spilled `.rgi`/`.rgl`.
|
|
// Each iteration computes the element address `s.ptr + i*esz` and
|
|
// either loads the whole element into the named local or pulls each
|
|
// tuple field into its own local. Mirrors cmd/w6c/cgen.c N_FORRANGE
|
|
// byte-for-byte (label names + labelseq consumption order).
|
|
fn cgforrange(c: *cgen, n: *node) void = {
|
|
let slc: *node = n.lhs;
|
|
let slclocal: *local = nil;
|
|
let slctn: *node = nil;
|
|
if (slc != nil) {
|
|
if (slc.kind == nkind.N_IDENT) {
|
|
slclocal = localfindnode(c, slc.str);
|
|
if (slclocal != nil) { slctn = slclocal.tnode; };
|
|
};
|
|
};
|
|
// Element type — peek through TSLICE/TARRAY for the tuple param walk.
|
|
let elemt: *node = nil;
|
|
if (slctn != nil) {
|
|
let sk: nkind = slctn.kind;
|
|
if (sk == nkind.N_TSLICE) { elemt = slctn.lhs; };
|
|
if (sk == nkind.N_TARRAY) { elemt = slctn.lhs; };
|
|
};
|
|
// esz: raw elem byte size. For tuple-element slices `[](T0, T1)`,
|
|
// C cgen reads the resolved tuple's size (sum of raw param sizes,
|
|
// no slot-padding) so e.g. `(i64, i64)` is 16, `(i32, i32)` is 8.
|
|
// elemsizeof returns 8 for non-primitive elem, which would be
|
|
// wrong here — compute from the tuple param walk instead.
|
|
let esz: i32 = elemsizeof(slctn);
|
|
if (elemt != nil) {
|
|
if (elemt.kind == nkind.N_TTUPLE) {
|
|
let total: i32 = 0;
|
|
let p: *node = elemt.list;
|
|
for (p != nil) {
|
|
total += paramfieldsize(p);
|
|
p = p.next;
|
|
};
|
|
esz = total;
|
|
};
|
|
};
|
|
let destruct: bool = (n.list != nil);
|
|
|
|
// .rgi (counter) + .rgl (length) scratch slots.
|
|
let iname: str = mkscratchname(c, "rgi");
|
|
let lname: str = mkscratchname(c, "rgl");
|
|
let ioff: i32 = localalloc(c, iname, 8, nil);
|
|
let loff: i32 = localalloc(c, lname, 8, nil);
|
|
|
|
// Per-binding (up to 8 — matches the C array). Parallel arrays so
|
|
// we don't depend on local-struct cgen.
|
|
let bind_off: [8]i32;
|
|
let bind_sz: [8]i32;
|
|
let bind_foff: [8]i32;
|
|
let bind_signed: [8]bool;
|
|
let nbinds: i32 = 0;
|
|
|
|
if (destruct) {
|
|
let tp: *node = nil;
|
|
if (elemt != nil) {
|
|
if (elemt.kind == nkind.N_TTUPLE) { tp = elemt.list; };
|
|
};
|
|
let field_off: i32 = 0;
|
|
let m: *node = n.list;
|
|
for (m != nil) {
|
|
if (nbinds >= 8) { m = nil; }
|
|
else {
|
|
let fsz: i32 = 8;
|
|
let signf: bool = false;
|
|
if (tp != nil) {
|
|
fsz = paramfieldsize(tp);
|
|
signf = paramissigned(tp);
|
|
};
|
|
let slot_sz: i32 = fsz;
|
|
if (slot_sz < 8) { slot_sz = 8; };
|
|
bind_sz[nbinds] = fsz;
|
|
bind_foff[nbinds] = field_off;
|
|
bind_signed[nbinds] = signf;
|
|
let bnm: str = m.str;
|
|
if (bnm.len > 0) {
|
|
bind_off[nbinds] = localadd(c, bnm, slot_sz, tp);
|
|
} else {
|
|
bind_off[nbinds] = localalloc(c, mkscratchname(c, "fr"), slot_sz, tp);
|
|
};
|
|
field_off += fsz;
|
|
nbinds += 1;
|
|
if (tp != nil) { tp = tp.next; };
|
|
m = m.next;
|
|
};
|
|
};
|
|
} else {
|
|
let slot_sz: i32 = esz;
|
|
if (slot_sz < 8) { slot_sz = 8; };
|
|
bind_sz[0] = esz;
|
|
bind_foff[0] = 0;
|
|
// Single-binding signed-narrow detection: mirror C which
|
|
// reads `u->sub->kind` for the elem type.
|
|
bind_signed[0] = false;
|
|
if (elemt != nil) {
|
|
bind_signed[0] = paramissigned(elemt);
|
|
};
|
|
if (n.str.len > 0) {
|
|
// Register with elem tnode so x.field on a loop
|
|
// var resolves through the standard local-typed
|
|
// path instead of falling into the SB fallback.
|
|
bind_off[0] = localadd(c, n.str, slot_sz, elemt);
|
|
} else {
|
|
bind_off[0] = localalloc(c, mkscratchname(c, "fr"), slot_sz, elemt);
|
|
};
|
|
nbinds = 1;
|
|
};
|
|
|
|
// init: ioff(BP) = 0
|
|
emitline("\tMOVQ\t$0, ");
|
|
emitoff(ioff: i64);
|
|
emitline("(BP)\n");
|
|
|
|
// loff(BP) = len
|
|
let isarr: bool = false;
|
|
let isslicestr: bool = false;
|
|
if (slctn != nil) {
|
|
let tk: nkind = slctn.kind;
|
|
if (tk == nkind.N_TSLICE) { isslicestr = true; };
|
|
if (tk == nkind.N_TARRAY) { isarr = true; };
|
|
if (tk == nkind.N_TNAME) {
|
|
if (streq(slctn.str, "str")) { isslicestr = true; };
|
|
};
|
|
};
|
|
if (isslicestr) {
|
|
if (slc.kind == nkind.N_IDENT) {
|
|
if (slclocal != nil) {
|
|
emitline("\tMOVQ\t");
|
|
emitoff((slclocal.off + 8): i64);
|
|
emitline("(BP), AX\n");
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(loff: i64);
|
|
emitline("(BP)\n");
|
|
};
|
|
};
|
|
} else { if (isarr) {
|
|
let alen: i64 = 0i64;
|
|
if (slctn.rhs != nil) {
|
|
if (slctn.rhs.kind == nkind.N_INTLIT) { alen = slctn.rhs.uval: i64; };
|
|
};
|
|
emitline("\tMOVQ\t$");
|
|
emitint(alen);
|
|
emitline(", ");
|
|
emitoff(loff: i64);
|
|
emitline("(BP)\n");
|
|
} else {
|
|
cgexpr(c, slc);
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(loff: i64);
|
|
emitline("(BP)\n");
|
|
};};
|
|
|
|
let loopl: str = mklabel(c, "rloop");
|
|
let endl: str = mklabel(c, "rend");
|
|
let naturall: str = endl;
|
|
if (n.els != nil) { naturall = mklabel(c, "relseloop"); };
|
|
|
|
c.loopcontbuf[c.looptop] = loopl;
|
|
c.loopendbuf[c.looptop] = endl;
|
|
c.looptop += 1;
|
|
|
|
emitlabel(loopl);
|
|
emitline("\tMOVQ\t");
|
|
emitoff(ioff: i64);
|
|
emitline("(BP), AX\n");
|
|
emitline("\tMOVQ\t");
|
|
emitoff(loff: i64);
|
|
emitline("(BP), BX\n");
|
|
emitline("\tCMPQ\tBX, AX\n");
|
|
emitline("\tJGE\t"); emitline(naturall); emitline("\n");
|
|
|
|
// BX = base + i*esz
|
|
if (esz > 1) {
|
|
emitline("\tMOVQ\t$");
|
|
emitint(esz: i64);
|
|
emitline(", CX\n");
|
|
emitline("\tIMULQ\tCX, AX\n");
|
|
};
|
|
if (slc.kind == nkind.N_IDENT) {
|
|
if (slclocal != nil) {
|
|
if (isarr) {
|
|
emitline("\tLEAQ\t");
|
|
emitoff(slclocal.off: i64);
|
|
emitline("(BP), BX\n");
|
|
} else {
|
|
emitline("\tMOVQ\t");
|
|
emitoff(slclocal.off: i64);
|
|
emitline("(BP), BX\n");
|
|
};
|
|
};
|
|
};
|
|
emitline("\tADDQ\tAX, BX\n");
|
|
|
|
// Per-binding load from BX+foff.
|
|
let b: i32 = 0;
|
|
for (b < nbinds) {
|
|
let op: str = "MOVQ";
|
|
if (bind_sz[b] == 1) { op = "MOVZBQ"; }
|
|
else { if (bind_sz[b] == 4) {
|
|
if (bind_signed[b]) { op = "MOVSXD"; }
|
|
else { op = "MOVL"; };
|
|
};};
|
|
emitline("\t");
|
|
emitline(op);
|
|
emitline("\t");
|
|
emitoff(bind_foff[b]: i64);
|
|
emitline("(BX), AX\n");
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(bind_off[b]: i64);
|
|
emitline("(BP)\n");
|
|
b += 1;
|
|
};
|
|
|
|
if (n.body != nil) { cgstmt(c, n.body); };
|
|
|
|
c.looptop -= 1;
|
|
|
|
emitline("\tADDQ\t$1, ");
|
|
emitoff(ioff: i64);
|
|
emitline("(BP)\n");
|
|
emitline("\tJMP\t"); emitline(loopl); emitline("\n");
|
|
if (n.els != nil) {
|
|
emitlabel(naturall);
|
|
cgstmt(c, n.els);
|
|
};
|
|
emitlabel(endl);
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
// cgswitch — lower `switch (e) { case 1, 2: ...; case: default; }` to
|
|
// a chain of compares against the scrutinee. Scrutinee lands in a
|
|
// fresh 8B local slot so case bodies can spill SP without losing it.
|
|
// Cases are tried top-to-bottom; the `case:` arm with no exprs is the
|
|
// default and runs after all named arms fail. Mirrors cmd/w6c/cgen.c
|
|
// N_SWITCH: same labelseq consumption order so labels match byte-for-
|
|
// byte.
|
|
fn cgswitch(c: *cgen, n: *node) void = {
|
|
let swname: str = mkscratchname(c, "sw");
|
|
let sloff: i32 = localalloc(c, swname, 8, nil);
|
|
|
|
if (n.lhs != nil) { cgexpr(c, n.lhs); };
|
|
emitline("\tMOVQ\tAX, ");
|
|
emitoff(sloff: i64);
|
|
emitline("(BP)\n");
|
|
|
|
let endl: str = mklabel(c, "swend");
|
|
let defcase: *node = nil;
|
|
|
|
let cs: *node = n.list;
|
|
for (cs != nil) {
|
|
if (cs.list == nil) {
|
|
defcase = cs;
|
|
cs = cs.next;
|
|
continue;
|
|
};
|
|
let body: str = mklabel(c, "swcase");
|
|
let nxt: str = mklabel(c, "swnext");
|
|
let e: *node = cs.list;
|
|
for (e != nil) {
|
|
cgexpr(c, e);
|
|
emitline("\tMOVQ\t");
|
|
emitoff(sloff: i64);
|
|
emitline("(BP), BX\n");
|
|
emitline("\tCMPQ\tBX, AX\n");
|
|
emitline("\tJE\t");
|
|
emitline(body);
|
|
emitline("\n");
|
|
e = e.next;
|
|
};
|
|
emitline("\tJMP\t");
|
|
emitline(nxt);
|
|
emitline("\n");
|
|
emitlabel(body);
|
|
if (cs.body != nil) { cgstmt(c, cs.body); };
|
|
emitline("\tJMP\t");
|
|
emitline(endl);
|
|
emitline("\n");
|
|
emitlabel(nxt);
|
|
cs = cs.next;
|
|
};
|
|
if (defcase != nil) {
|
|
if (defcase.body != nil) { cgstmt(c, defcase.body); };
|
|
};
|
|
emitlabel(endl);
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
fn cgbreak(c: *cgen, n: *node) void = {
|
|
if (c.looptop > 0) {
|
|
let lbl: str = c.loopendbuf[c.looptop - 1];
|
|
emitline("\tJMP\t"); emitline(lbl); emitline("\n");
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
fn cgcontinue(c: *cgen, n: *node) void = {
|
|
if (c.looptop > 0) {
|
|
let lbl: str = c.loopcontbuf[c.looptop - 1];
|
|
emitline("\tJMP\t"); emitline(lbl); emitline("\n");
|
|
};
|
|
c.lastwasreturn = 0;
|
|
return;
|
|
};
|
|
|
|
|