Param-decl `name: T...` (Tparam.variadic=1, type []T), call-site
gather of N args into a fresh `[N]T`, forward via `xs...`, full
selfhost mirror, and lib/fmt graduated to the Hare shape.
Frontend:
- parse: `T...` after a param's type stamps Node.op=TK_ELLIPSIS
and breaks out (variadic must be last).
- check: resolve_type N_TFN / build_fn_type wrap the param type
as []T and set tp->variadic. N_CALL accepts either a tail of
args assignable to T (gather) or a single `xs...` spread of
[]T (forward); both bypass the "too many args" check on the
variadic slot.
- type: type_eq compares Tparam.variadic.
Cgen (cstage):
- call site: when the callee has a variadic last param,
materialise the tail args into a frame-resident `[N]T` via
localoff, write a 24B slice descriptor (ptr,len,cap), and
splice a synthesised N_IDENT into args[] so the downstream
widen/eval/pop loops see one slice slot. Tagged-element types
route each store through cg_widen_tagged_store. Forwarding
skips gather: the N_SPREAD wrapper is replaced with its inner
slice expression. Empty form writes {nil,0,0}. args[] / widen[]
bump from 16 to 64 to accommodate Hare's mixed-arg printers.
Selfhost mirror:
- lib/ww/parse: `T...` mark on N_PARAM.op.
- cgen: varargseq counter on Cg; scanlocals reserves
@vararg_d_N + @vararg_sl_N per variadic call (seq recorded on
N_CALL.uval so cgcall picks the same names). cgcall does the
same gather/forward and N_IDENT splice. cgfnparams treats
variadic params as 24B slice slots via a synthesised TSLICE
tnode. pushargsrev skips the tagged-widen detection for
variadic params (effective type is []T, not tagged).
- rhstargetname now recognises N_TRUE/N_FALSE/N_RUNELIT and
typed N_INTLIT so the variant-tag lookup finds bool/rune/iN
variants instead of falling through to "first non-str" (which
misassigned tag 0 to bool in tagged unions like formattable).
lib/fmt graduated: print/println/fprint/fprintln/errorln/fatal
take `args: formattable...`. Bare `error` (no -ln) is skipped —
the leaf name collides with strconv's `type error = !(invalid |
overflow)` under the driver's flat namespace.
Tests: 5 new e2e rows (plain gather, zero-arg, tagged element,
forwarding, fmt.println end-to-end). lib/CLAUDE.md workaround
paragraph replaced with the Hare-shape description.
Six fixes across the toolchain, surfaced by lib/lisp porting work.
1. f64 compound assigns (`acc += d`, `-=`, `*=`, `/=`). Both stages
load slot → X1, OP X0 into X1, store back (ADDSD/SUBSD/MULSD/
DIVSD are reg-reg only). Previous MOVSD-overwrite dropped the
OP. Locals and top-level lets.
2. Top-level `[N]u8` arrays + `&arr[i]`. let_emit_size grows a
TY_ARRAY branch so zero-init DATAW lands; cgindex / N_INDEX
store / `&base[i]` all detect a global array base and use
LEAQ name(SB) instead of LEAQ (BP). TK_AMP no longer pre-
evaluates the operand as a value-load — `&base[i]` computes
base + i*esz directly. Unblocks Hare's static-buffer pattern:
strconv.{u64,i64,f64}tos graduate to module-level `*_buf`
arrays and return owned views.
3. Cross-module `pkg.Enum.MEMBER`. Nested N_DOT chains that
don't fold to a known shape now emit `MOVQ <leaf>(SB), AX`
(mirrors the bare-IDENT unresolved fallback), so isolation
probes — and the test 990 cgen-match floor — stay consistent
across stages. strconv exposes `base` as a real `enum i32`;
callers updated. The `main` exemption (linker entry-point
keeps bare name even when not exported) mirrors C-side
collectmods into selfhost cgendecl.
4. Sum-typed parameter ABI. lib/bytes.{index,rindex} take
`(u8 | []u8)` needle; lib/strings.byteindex / rbyteindex take
`(str | rune)` needle (Hare-shaped; the byte-wise misnomer
`index` is dropped). tagged_arg_size cap bumps to 48 (6 int
regs), with a new partial-fit branch on the callee: when an
N-word tagged arg overflows remaining regs, fill what fits and
stitch the rest from positive BP offsets. scanlocals MCASE
handles slice binds (24B) and walks each arm with a saved /
restored seenmark set so two arms naming the same local each
get their own slot — matches cstage's per-arm scope reset.
5. 4-reg tagged-return ABI (AX=tag, DX=word0, CX=word1, R8=word2),
up from 3 regs. Slice-payload variants (`([]T | E)`, slot 32B)
round-trip ptr/len/cap end-to-end. Every receive site updates:
let-init via cgwidentaggedstore, match scrutinee spill, cgindex
tagged-element load (both N_IDENT and fallback bases),
pushargsrev tagged-ident arg (reads word count from slot size),
cgreturn slice variant in the shuffle path.
6. `expr: TaggedAlias` is a widening, not a re-interpret. C cgen +
selfhost cgwidentaggedstore peel an N_CAST whose destination IS
the union — so cgexpr's natural shape (str: AX=ptr, BX=len;
slice: AX=ptr, BX=len, CX=cap) is consumed by the matching
concrete-variant branch instead of being misread as a tagged
AX/DX/CX triple. Inner casts to a concrete variant (`7: i32`)
keep their type for proper tag lookup. `[N]Alias` arrays
resolve element size via slotsize + aliaslookup, and aliaslookup
strips a `pkg.` prefix so cross-module references work.
lib/fmt grows `formattable = (i64 | str | bool | rune)` plus
`printv` / `printlnv` taking an explicit `[]formattable` slice (the
receive side of Hare's `args: formattable...`). Call-site variadic
gather isn't wired — callers either hand-build the slice or compose
strconv.i64tos + strings.concat.
700_e2e: 114 → 123 rows (f64 compound, top-level u8 arrays + `&buf[i]`,
pkg.Enum.MEMBER, sum-typed (str|rune) and (u8|[]u8) params, 4-reg
slice-return ABI, formattable array). 26/26 tests, bootstrap stable
through ww4.
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.
Three tagged-union gaps:
1. Struct-payload widening was broken at every site (call, let,
assign, return, struct-field init). cg_widen_tagged_store now
materialises str / scalar / struct-lit / struct-ident / tagged
payloads at slot+8+field_off and writes the tag last. Call sites
route through cg_widen_tagged_push (scratch slot + push high→low).
2. Tagged → wider tagged widening forwarded the source tag verbatim.
cg_widen_tag_remap emits a CMPQ-chain switch that translates each
source variant index to the destination's, then zero-pads to the
wider slot. type_eq grew a TY_TAGGED arm (was returning 1 for any
two unions); type_assignable now accepts variant-subset and
rejects the rest.
3. `(...inner | T)` spread parses (cmd/wcc/parse.c, lib/ww/parse).
Marks Node.op = TK_ELLIPSIS; resolve_type unwraps NAMED + flattens
when the spread bit is set so aliases inline like Hare's
tagged_type unwrap flag.
Selfhost mirror: spread parser ported. Cgen widen helpers not yet
mirrored — wwstage stays byte-identical to cstage on the existing
test corpus, but will emit wrong asm if user code uses the new
patterns (probe sp2 shows the divergence).
700_e2e: 9 new rows covering call/let/assign/return × struct +
tagged subset, plus the spread-flatten case.
`type error = !(invalid | overflow)` miscompiled — istaggedtype
only matched N_TTAGGED directly, so an `e: error` param spilled
as 8B scalar and the match's slot+8 read trailed into saved BP.
Mirror isstrtype's alias+bang unwrap; add resolvetagged() for
is/as/match sites that need the inner N_TTAGGED. Frame scan
counts via slotsize so wwstage stays byte-identical to cstage.
Unblocks lib/strconv.strerror.
i64tos / u64tos / f64tos return a fresh owned str (caller frees via
os.free) instead of writing into a caller-supplied [N]u8. Adds typed
variants (i32tos / i16tos / i8tos and u32 / u16 / u8) and the missing
base parameter on stoi64 / stou64 + typed parse wrappers.
Base values are exported as plain-i32 `def`s (strconv.DEC,
strconv.HEX_UPPER, ...) rather than a `base` enum: cross-module
`strconv.base.DEC` chains miscompile in the cstage cgen — it emits a
memory load through `base(SB)` rather than inlining the constant.
The Sdef path resolves correctly, so callers say `strconv.DEC` and
both cgens lower to an immediate.
Also renames strings.byteindex / rbyteindex to strings.indexbyte /
rindexbyte, matching bytes.indexbyte and reserving the Hare name
`byteindex` for the future `(str | rune)`-needle shape.
fmt drops printint / printlnint / fprintint — those were stand-ins
for variadic `fmt::println(42)`; with the owned-str graduation the
substitute is one call: `fmt.println(strconv.i64tos(42, strconv.DEC))`.
strerror is sketched in a comment but not shipped — match arms over
the wider `error = !(invalid | overflow)` union still expose a
cstage-vs-wwstage spill divergence.
.data now lives at the end of the dyn-path R+W PT_LOAD, just after
.dynamic. The single segment covers .got.plt + .dynamic + .data; its
filesz drops trailing zeros (BSS) while memsz spans the full extent.
Relocation moves from main.c into each emit function so the static
and dynamic paths use their own data_va — text→data refs land on the
right VA regardless of path. Removes the early-error in dynout.c
that previously refused any .data with -l/-L.
Tests: 810_dyn gains two new dyn+.data fixtures (mutable read+write
of an i32, plus a zero-init i64 verifying the BSS scan still produces
a valid p_filesz<p_memsz under the shared segment).
Scan the consolidated .data buffer (post-relocation) for trailing zero
bytes; set the R+W PT_LOAD's p_filesz to exclude them while p_memsz
covers the full region. The loader zero-fills the gap, so behaviour is
unchanged. Saves up to a page per binary on programs whose globals are
zero-init.
Mirrored in selfhost/cmd/w6l/out.ww so test 992's byte-identity diff
still holds. Dynamic-link path is untouched — it still errors on any
mutable global; that's the next feature.
N_IDENT for a slice local now loads (AX=ptr, BX=len, CX=cap), matching
the existing global-slice load.
cgexpr learns N_SLICE: `base[lo:hi]` leaves the same triple in
registers, so callers (return, arg push, reassignment) all share
one shape. The let-init's pre-existing N_SLICE direct-store path
stays as a specialisation; the new generic slice let-init catches
fn-returning-slice and slice-ident initialisers.
N_ASSIGN gains a TY_SLICE branch parallel to TY_STR: store all
three halves to the local slot or, for globals, stash CX into DI
before LEAQ-ing the address (CX is both the new cap and the
address scratch).
Field write extends the existing TY_TAGGED branch with an is_global
arm: LEAQ name(SB),CX after cgexpr (no AX/BX clobber), then MOVQ
into slot+foff+0 (tag) and slot+foff+8 (value, plus +16 for str-
typed variants).
Field read now treats tagged fields specially — load AX=tag,
DX=val0, CX=val1 (when union >16B), mirroring the tagged-return
ABI that let-init and match dispatch already expect. Previously
the scalar-load path read 8B into AX and left DX/CX with junk,
which silently broke local tagged-field reads too.
f32 → 4B slot, f64 → 8B. C cgen bakes the FLOATLIT bit pattern into
DATAW directly; selfhost emits zero-init only (its parser doesn't
lex N_FLOATLIT yet). Read/write goes LEAQ name(SB),CX + MOVSS/MOVSD
since w6a has no D_EXTERN operand form for SSE moves.
Use the new DATAR mechanism so str-literal init on a top-level
mutable `let` lands in .data and links cleanly.
emit_lets, when it sees `let s: str = "lit"` (non-empty strlit),
emits:
DATAW s(SB),"<8 zero placeholder><8 LE bytes of len>"
DATAR s+0(SB),<strlit_label>(SB)
The linker patches the placeholder with the strlit's runtime VA at
program load time, so `s.ptr` reads as the real pointer and `s.len`
as the literal length. A new let_pre_intern pass scans top-level
lets ahead of emit_data so the strlit gets a DATA row in the same
.s file; running emit_lets after emit_data instead would have
flipped the (DATA strlits, DATAW lets) section order in the .s and
broken byte-identity with the wwstage cgen.
The wwstage cgen still emits the zero-init shape for str lets,
which only matters if the wwstage is asked to compile source that
uses str-literal init. None of the selfhost combined sources do
that today, so test 994 / 990 stay green. The selfhost mirror for
DATAR + DATAW + this w6c branch is a follow-up.
630_let_global gains two fixtures: a length-readback and a first-
byte readback through the patched ptr.
Unblock literal initialisers for str/slice/struct globals by wiring
an R_X86_64_64 relocation kind through both assembler and static
linker.
w6a:
- new A_DATAR directive, syntax `DATAR slot+off(SB),target(SB)`,
records an R_X86_64_64 reloc at slot+off in .data pointing at
target. The slot must be pre-defined by a prior DATAW;
- parse_operand learned the `name+disp(SB)` shape so the slot's
byte offset can be addressed explicitly;
- Areloc carries a `section` flag (0=.text / 1=.data) and obj.c
splits the reloc list into .rela.text and .rela.data, emitting
the latter conditionally with sh_info pointing at .data.
w6l:
- Lrel grows the same `section` flag; obj.c loads `.rela.data`
sections into the global reloc list with offsets shifted by
each input's data_off;
- pass.c handles R_X86_64_64: target VA is data_va+sym.val for
in_data symbols (else text_va+sym.val), addend is added, and
the 8-byte slot is patched in l->data (or l->text).
Inputs without DATAR are unaffected — bootstrap, 991 (selfhost .o
diff) and 992 (selfhost exe diff) keep their byte-identical
output. 520_datar covers the new path: asm a DATAW+DATAR pair,
verify .rela.data has exactly one R_X86_64_64 entry, link, run,
confirm the relocated pointer feeds a 5-byte write that prints
"hello".
Selfhost mirror + w6c emission for str/slice/struct literal init
land in follow-ups.
Extend top-level mutable `let` to cover structs. Same approach as
str / slice: take the field-access base through &name(SB) instead
of off(BP).
- emit_lets / emitletdataw: emit `sizeof(T)` zero bytes for any
struct global without a baked-in initialiser. Struct-literal
init is skipped → undefined symbol at link if used;
- cgdot read path: when the IDENT base's local lookup misses and
the name is a struct let, LEAQ name(SB), CX and load the field
at fi.foff(CX) with the width-aware op (MOVQ / MOVL /
MOVZBQ / MOVSXD; MOVQ pair for str fields);
- cgassign write path: parallel handling for plain `=` (incl. str
fields) and the compound ops (+=, -=) via load → push → eval
rhs → combine → store with a re-LEAQ between cgexpr clobbers.
Tagged-union fields on struct globals are unsupported in v1 — the
local path's tagged branch isn't generalised yet. Whole-struct
by-value flow through expressions remains NYI (matches the local
status). 630_let_global gains 3 fixtures (read/write, compound +=,
narrow u8 field); selfhost mirror keeps test 990 / 994 / 995 byte
identical; bootstrap fixed point holds.
Extend top-level mutable `let` to cover slices. Same shape as the
str work, with one more 8-byte field and the address holder CX
overwritten by the cap as the last load step:
- emit_lets / emitletdataw: 24-byte zero DATAW for `let v: []u8;`
(and the trivial `nil` init); no slice-literal syntax exists
so the no-init path is the only supported shape;
- cgident: LEAQ name(SB), CX → MOVQ (CX), AX → MOVQ 8(CX), BX →
MOVQ 16(CX), CX, so the slice ABI triple lands in (AX, BX, CX);
- cgdot: .cap delta 16 wired alongside .ptr / .len through the
same &name(SB) base.
Slice reassignment (`v = some_slice;`) is still unsupported — slice
values don't yet flow as a full (AX, BX, CX) triple through general
expressions even for locals — so reads/`&` are the supported surface
today. Manual fill through `(&v): *u64` continues to work.
Tests 630 (10/10), 990, 994, 995 stay green; bootstrap fixed point
holds.
Extend top-level mutable `let` to cover str. The cgen now:
- emits a 16-byte zero DATAW for `let s: str;` (and the trivial
`nil` / `""` inits); a non-empty strlit init is skipped because
a compile-time .data → .text reloc isn't supported yet, so the
user gets a clean undefined-symbol error at link;
- loads `s` as `(LEAQ s(SB), CX; MOVQ (CX), AX; MOVQ 8(CX), BX)`
so the (AX=ptr, BX=len) pair convention is preserved;
- stores via the same `&s` indirection for `s = expr;` and routes
the `.ptr` / `.len` pseudo-field N_DOT branch through it; and
- tracks the declared type on each LetVar so cgident / cgdot /
cgassign pick the right load/store shape.
Selfhost cgen mirrors all four paths byte-for-byte; test 990
(cgen-match on err.ww) and tests 994/995 (self-rebuild) stay
green. 630_let_global gains two new fixtures (`let msg: str;` +
runtime assign, plus reassign from a helper).
Slice and struct globals still NYI — same scope deferred.
Third step toward writable globals. The C cgen and its selfhost
mirror now:
- emit DATAW <name>(SB),"<8 LE bytes>" for every top-level `let`
whose type lands in the scalar set (i8..i64/u8..u64/bool/rune/
int/uint/uintptr/ptr; floats and multi-word types deferred);
- drop the "no writable .data" silent-drop guard at the N_IDENT
store path, replacing it with a RIP-relative MOVQ for `=` and
a load→combine→store sequence for the compound ops; and
- route `&name` through LEAQ name(SB) instead of dropping it.
Type aliases resolve via aliaslookup so `type counter = i32; let c:
counter = 0;` still emits a DATAW slot. Non-literal initialisers
silently skip, which surfaces as a clean undefined-symbol error if
the binding is ever referenced.
The selfhost mirror lands in the same commit because test 990
diffs the C cgen against wwdump_ww -c on err.ww (which has
top-level `let nerrors: i32 = 0; ... nerrors += 1;`). Any drift
between the two cgens makes 990 fail. Bootstrap stays at a fixed
point: ww2 == ww3 == ww4 byte-identical.
Second step toward top-level mutable `let`. The static path now loads
.data PROGBITS sections from input .o files, page-aligns them after
.text, and emits a second PT_LOAD (R+W) covering them. Relocations
targeting data symbols compute against the data VA; text→text
displacements still cancel the absolute VAs and stay correct.
Inputs without any .data keep the original single-PT_LOAD layout
byte-for-byte — 992 (selfhost w6l .o diff) and 995 (self-rebuild)
depend on that invariant.
Dynamic-link path (-l/-L) rejects .data for now with a clear error;
folding writable globals into the existing R+W segment alongside
.got.plt/.dynamic is a follow-up.
First step toward top-level mutable `let`. Adds a sibling directive to
DATA whose bytes land in a separate writable .data PROGBITS section
(SHF_ALLOC|SHF_WRITE, STT_OBJECT) instead of .text. The section is
emitted only when DATAW was used, so inputs without it produce a
byte-identical .o — tests 991 (selfhost .o diff) and 995 (self-rebuild)
keep passing unchanged.
w6l still treats data-resident syms as undefined; that's the next step.
Mirrors Hare's `fs::flag` and `io::whence`:
export type flag = enum i32 {
RDONLY = 0,
WRONLY = 1,
RDWR = 2,
CREATE = 64, // 0o100
TRUNC = 512, // 0o1000
};
export type whence = enum i32 { SET = 0, CUR = 1, END = 2 };
open/tryopen/lseek signatures take the enum types (`flags: flag`,
`w: whence`) so callers get type-checked: `os.open(p, os.flag.RDONLY,
0)` is the correct shape, and `os.flag.WRONLY | os.flag.CREATE |
os.flag.TRUNC` typechecks as a `flag` via the same-named-type rule.
Callers in selfhost/cmd/{ww,w6c,w6a,w6l,wwdump} updated from
`os.O_RDONLY` etc. to `os.flag.RDONLY`. SYS_* syscall numbers kept
as `def` for now (internal-only, ABI surface, no Hare analogue in
this scope).
selfhost/test/smoke.ww keeps its standalone-compile property by
using a numeric literal (`0`, RDONLY's value) for the open flags
arg — probe 6 in 990_selfhost compiles smoke.ww with no `use`
expansion, so cross-module type refs like `os.flag.RDONLY` can't
resolve there. Untyped 0 → flag via type_isnum.
Driver-side concatenation flattens module names, but enum member
lookup keyed off the exact lhs ident — so `whence.CUR` worked while
`os.whence.CUR` fell through to w6l with `undefined main.whence`.
C side: fold TY_ENUM members in the post-cexpr cascade too, not
just the early SK_TYPE shortcut. The recursive cexpr lands the
inner N_DOT(os, whence) on the named enum type; the outer access
then folds normally.
Selfhost: cgdot now treats `N_IDENT.MEMBER` and `N_DOT.MEMBER` the
same way, keying off the leaf name. enumlookup strips a trailing
`.`-prefix from the lookup key.
Adds e2e test 700: `use os; os.whence.CUR as i32 == 1`.
w6c_ww now compiles enum end-to-end and emits byte-identical
asm to the C w6c on the new 994 corpus case (`type mode = enum u8
{ R, W, RW = R | W }; main() { return (mode.RW): i32 }`). Mechanism
mirrors the C side:
- collectenums walks every `type X = enum {...}` at file scope and
pre-resolves each member's u64 value (auto-increment from prior,
sibling-ref folding for `RDWR = READ | WRITE`).
- cgdot recognises `EnumName.MEMBER` before the local lookup and
emits MOVQ $value, AX directly.
- cgtypeassert short-circuits when either side is enum: cgexpr on
the LHS lands the value in AX with the right integer width; no
tag/unwrap.
main.combined.ww (wwdump/ + w6c/) regenerated by ww build.
`type Foo = enum [intT] { NAME [= expr], ... };`. Storage defaults
to i32; members auto-increment from 0 (or last+1) when `= expr` is
omitted, and value expressions can reference earlier siblings —
enough surface for io::mode-style flag enums (`RDWR = READ | WRITE`).
`Foo.MEMBER` folds to an N_INTLIT in the checker, typed as the
named enum. Binops on enum values yield the same enum (type_eq on
the named pointer), so `mode.R | mode.W` is a `mode`. Enum ↔ int
is a reinterpret-only `as` cast — same register, no tag wrap — so
`mode.RDWR as i32` and `1 as mode` both work without runtime ops.
`is`/`?`/`!` are still tagged-union-only. CSP runtime (chan/proc)
is unchanged; only the type-system slot is touched here.
@test parsing already works under ww_ww (parseattrs lives in the
shared lib/ww/parse/decl.ww, picked up by both Cstage and wwstage),
so this is the test-side parity: 997 is 910 with `ww run` swapped
for `ww_ww run`, exercising the selfhost driver+compiler+assembler+
linker end-to-end on the same attest_pass.ww fixture. Suite is now
22 tests.
Three more structural checks from C check.c ported to selfhost,
at the AST level (no resolved tinfo).
is/as validity: e is T / e as T require e's declared type to be a
tagged union and T to name a variant. Mirrors the case-variant
check that just landed.
let init-type and return-type assignability: a new exprtype helper
infers an AST type-node for literal/ident/call/cast/?/as/is
expressions; isassignable approximates C type_assignable on the
shapes we can resolve — exact match, untyped numeric → typed
numeric, untyped nil → ptr/slice/chan/fn, variant inclusion, and
two-primitive-mismatch.
isassignable returns (ok, confident). When confident=false the
check emits no error — better to miss a real bug than fire a
false positive on a binary-op expression we can't infer. This
keeps existing selfhost code clean while still catching the
common typo cases (let x: bool = 42; return "hi" from i32 fn).
Naming: all new helpers follow Plan 9 run-together convention per
CLAUDE.md (`typeeqast`, `isassignable`, `exprtype`, ...). Earlier
work that used snake_case helpers (`case_variant_in`,
`check_match_exhaustive`, ...) got the same treatment — bulk
renamed in this commit.
Five new rows in 950_selfcheck exercise the new checks
(is-not-a-variant, two let mismatches, return mismatch, plus the
case-variant row already there).
`match (u) { case T => ... }` where T isn't a variant of u was
silently accepted by both checkers. The cgen would emit a tag
comparison against an index that never appears, leaving the arm
unreachable — wasted code that's almost always a bug or typo.
C check.c now mirrors the existing is/as rule for match arms:
each `case T` and each alt of multi-pattern `case T1 | T2` is
checked against the scrutinee's variant list via variant_present.
selfhost check.ww gets the same shape with AST-level type_eq_ast
comparison. Both checks land in the same scope-aware pass that
already runs exhaustiveness and ? subset.
New test rows in 300_check (C side) and 950_selfcheck (selfhost
side) exercise both single-pattern and multi-pattern alt typos.
The 950 driver's err_present detector picks up the new
"case: not a variant" prefix.
The selfhost checker did name resolution only — anything tagged-
union-shaped sailed through silently. The C check.c implements
three structural checks; this commit mirrors them at the AST level
in selfhost/cmd/wcc/check.ww:
1. Match exhaustiveness: every variant of the scrutinee's tagged
union must be covered by a case arm (incl. multi-pattern alts)
or a default arm. Operates on the scrutinee's declared type
(N_TTAGGED via N_IDENT's sym.decl.lhs).
2. ? subset propagation: each error variant of the operand's type
must be a variant of the enclosing fn's return type. Enclosing
return must itself be a tagged union when the operand has any
errors.
3. !-flag semantics: in flag-aware mode (any variant marked `!T`),
error subset = flagged variants. Legacy mode (no flags) =
everything-but-first. is_error_variant unifies both rules.
No tinfo / type-inference work: the checks read declared AST type
nodes directly. `resolvealias` chases N_TNAME → typedecl body to
handle aliased tagged unions. `type_eq_ast` does structural
comparison on the subset of type-expression shapes the checks
encounter (TNAME by string, TPTR/TSLICE/TCHAN recursive).
Folded into resolvewalk rather than a separate second pass, so the
checks see the same per-statement scope state as resolve. fnret is
threaded through resolvefnbody so ? can find the enclosing return.
New test/wcc/950_selfcheck.c — five rows exercising each error path
(missing variant, non-tagged enclosing, missing error subset
member, the flag-aware happy path, the flag-aware missing-error
case). Test suite now reports 21 ok.
Hare-style `@test fn check_foo() void = { ... }` now parses. The
attribute is recognised by making the args list optional in
parseattrs: `@symbol("rt_syscall")` still requires the parens;
`@test` doesn't. Same change mirrored in lib/ww/parse/decl.ww.
The runner (test/wcc/910_at_test.c) scans a fixture for
`@test fn IDENT(`, synthesises a wrapper `main()` that calls each
test fn, builds it via `ww run`, and asserts exit 0. A failing
@test would either explicitly call abort or trip a runtime trap
(div-by-zero, etc.) and the whole driver exits non-zero.
The 910_at_test target sits alongside the existing C-side test
binaries; `make test` now runs 20 tests instead of 19.
Fixture: test/wcc/data/attest_pass.ww exercises two passing tests
(simple arithmetic and a match-with-yield).
C cgen has carried defer for a while (defers[] global + reverse
walk on every return). Selfhost cgen now mirrors:
- cgen struct: deferbuf (**node, LIFO stack) + defertop counter.
- cgstmt N_DEFER: push n.lhs.
- cgreturn: rundefers() at entry — same as the C cgen pattern.
- cgfn fall-through return: rundefers() before zero-AX+RET.
DEFER_MAX = 16 matches C cgen.
Two new e2e rows: defer with an explicit `return acc;` (321 mod 256
= 65), and defer firing on an implicit void-fn fall-through (87).
Both rows verified via the wwstage cgen too.
Defer's semantics: queued exprs fire LIFO before the return expr
is evaluated, so a return that reads memory mutated by a deferred
call sees the post-defer state. Matches C cgen and Hare.
`match (e) { ... }` can now sit in expression position, with each
arm using `yield expr;` to produce the match's value:
let v = match (r) {
case let n: i32 => yield n + 1;
case let s: str => yield s.len: i32 + 100;
};
TK_YIELD keyword + N_YIELD AST node, both appended at the tail of
their enums to keep prior numeric values byte-stable for the
wwdump-diff gates.
Checker: cexpr for N_MATCH walks each arm's body looking for the
first N_YIELD; the match's type is the unified yield type (or
ty_void if no yield, preserving the statement-form semantics).
Mismatched arm yields are flagged.
Cgen: a yield-target stack (separate from the loop break stack)
holds each enclosing match's end label. N_YIELD evaluates its
expression into AX (and BX for str) and JMPs to the topmost entry.
cgmatch pushes its end label on entry and pops on exit.
Selfhost mirror: lib/ww/lex/tok.ww kwtab+name, lib/ww/ast.ww
N_YIELD def+print, lib/ww/parse/stmt.ww yield-stmt; selfhost cgen
adds a yieldbuf to the cgen struct and a cgyield helper. Verified
end-to-end: a yield-using program compiled via the wwstage cgen
matches the C-cgen build's exit code.
A tagged union with exactly one `*T` variant and one `void` variant
collapses to a single 8-byte pointer slot, where the null bit
pattern is the void variant and any non-null is the *T variant.
Mirrors Hare's `(*T | null)` ABI optimisation.
Detected in resolve_type when the post-flatten variant list has
exactly two entries of the right shape; Type.nullable = 1 and
size = 8. Codegen branches every tagged-handling site on the flag:
- match: discriminator = pointer-vs-zero, not slot+0 tag word.
Binding for the *T case copies the same word (the pointer itself)
rather than slot+8.
- is/as: same ptr-vs-zero discriminator.
- ?: null = error (propagate AX=0 to caller's matching null
encoding); non-null = success (AX is already the pointer).
- !: null aborts; non-null falls through with AX = pointer.
- let-init / return: spill or set just AX (no tag/value pair).
- call-arg push: push only AX, not the now-unused DX/CX.
Prologue spill already pulled size/8 = 1 arg register via the
existing tagged-arg loop, so no change needed there.
Two existing helpers in cgen.c get nullable-aware spelling:
type_isnullable() and nullable_ptr_tag() (which variant index is
the *T side; the void side is the other one).
The Hare-style `(*T | null)` spelling isn't supported — `null` is
not a type keyword in ww. Callers use `void` instead, which is
already a real type. The result is the same bit-level layout.
Final piece of the os module graduation: the three try* wrappers
move off the (T | str) placeholder shape. `oserror` becomes a real
Hare-style error type (`!i64` instead of plain `i64`), so it's
picked up by ?-propagation as the error half without callers having
to name it.
tryread: (i64 | oserror) was (i64 | str)
trywrite: (i64 | oserror) was (i64 | str)
tryopen: (i32 | oserror) was (i32 | str)
Callsites updated: wwdump uses tryopen; the e2e trywrite probe
matches on os.oserror and validates -EBADF for a bad fd (-9 instead
of the old "write failed" string length).
selfhost/test/smoke.ww switched to raw os.open(2) instead of
os.tryopen for probe 7 — same reason as the os.readall switch in
the prior commit: probe 6 in 990_selfhost compiles smoke.ww
standalone, and cross-module type refs like `os.oserror` don't
resolve in that mode.
A type prefixed with `!` is flagged as an error variant. When any
variant in a tagged union carries the flag, `?` propagation uses
those (and only those) as the error subset; the unflagged variant
is the success type. The legacy "first variant = success" rule still
applies when no `!`-flag is present, so existing code keeps working.
- TK_NOT in parsetype → N_TBANG wrapper (lhs = inner type expr).
Appended to Nkind tail for wwdump-diff byte stability.
- resolve_type N_TBANG: wraps primitives in a fresh Type copy so the
iserror bit doesn't taint shared globals like ty_str/ty_i32; flips
the bit in place on NAMED (already unique per alias decl).
- Type.iserror; type_named and typedecl inherit it from under.
- New check.c helpers: tagged_has_errflag, tagged_is_error_variant,
tagged_success_type. N_TRYPROP uses them to find the error subset
and verify each error variant is propagatable to the enclosing
return.
- cgen mirrors with cg_tagged_success_tag + cg_variant_is_error.
`?` compares AX against the success tag (no longer always 0) and
remaps each error variant's tag for the enclosing fn. `!` aborts
on any non-success tag.
strconv.invalid and strconv.overflow now use `!`-flagged shape
(`!i32` and `!void`) — visible signal in the API surface that they
are error types, matching Hare. The (i64 | invalid | overflow)
return shape and behavior are unchanged for callers; their match
arms still bind the same way.
Selfhost: lib/ww/parse/parse.ww recognises `!T` and emits N_TBANG.
The selfhost typechecker and cgen ignore the flag — none of the
selfhost sources use `!`, so byte-identity gates are unaffected.
The selfhost mirror catches up when there's a source using it.
`type invalid = i32` (payload: byte index of first bad rune; mirrors
Hare's strconv::invalid = !size) and `type overflow = void` (Hare's
overflow = !void). stoi64/stou64 now return these instead of the
str-error placeholder. atoi64 dropped — lib/CLAUDE.md says graduate
in one go, don't keep both shapes around.
To produce the void variant payload, `void` is now a real
expression literal (TK_VOID kw, N_VOIDLIT). It evaluates to ty_void;
codegen emits MOVQ $0, AX. Both kinds are appended at the tail of
their enums to keep prior numeric values byte-stable for the
wwdump-diff fixtures.
check_file reorder: USE declarations are now installed in pass 1
alongside the type-decl placeholders so dotted type references
(`strconv.invalid` from a typedecl body) resolve. DEF/FN/LET silently
overwrite a USE-occupied slot — matches the old behavior where USE
silently no-op'd when a same-name fn/def existed (the conflict
manifested in selfhost main.combined.ww at `use parse;` colliding
with `export fn parse(a)`).
selfhost mirror: lib/ww/lex/tok.ww kwtab+name; lib/ww/ast.ww
N_VOIDLIT def+print; lib/ww/parse/{expr,parse}.ww TK_VOID handling;
selfhost/cmd/wcc/cgenexpr.ww N_VOIDLIT codegen.
Replaces the -1 sentinel return on indexbyte/byteindex/rbyteindex/
index with Hare's optional-shaped tagged union. Callers `match` on
the result and bind the index from the i32 variant.
Two cgen fixes were needed first:
1. resolve_type for N_TTAGGED rounded value payload up to an 8-byte
multiple. (i32 | void) was sized 12 — tag (8) + payload (4) —
which made the reg-passing ABI compute size/8 = 1 word and drop
the value word.
2. The call-arg push path special-cased struct and slice args but
not tagged-return calls. A nested `f(g())` where g returns a
tagged union pushed only AX (tag); the matching pop loaded a
stale DX/SI for the value. Now pushes AX/DX[/CX] in order so
the pop side drains tag → arg-reg[0], value(s) → arg-reg[1..].
strings.contains rewritten to match on the new tagged result. No
other callers existed in lib/ — bufio/io still use their own
shapes.
`expr?` previously did a brain-dead RET through whatever AX/DX/CX
held — only safe when operand and enclosing fn had identical variant
ordering. Tests relied on that alignment by construction.
Now:
- Typecheck: each non-first variant of operand must appear as a
variant of the enclosing fn's return tagged union. Enclosing must
itself be tagged (a non-tagged return has no slot for errors to
land in).
- Cgen: on tag != 0, walk operand's error variants and emit a
conditional tag remap (cmp/jne/mov/jmp) for any whose index in
enclosing differs from operand's. Identity cases emit nothing,
so same-shape operands cost zero extra instructions.
Selfhost cgen doesn't implement N_TRYPROP at all (no selfhost source
uses `?`); byte-identity tests still pass.
One existing e2e row used `?` with main returning i32 — relied on
the old loose semantics. Switched to `!` (abort-on-error); it was
exercising success-unwrap, not propagation.
Struct members can be `struct { ... }` (anonymous nested) or a bare
named type, in addition to `name: type`. The inner struct's fields
are promoted to the outer scope with offsets shifted by the embed
base; codegen already keys off Tfield.offset so cgen needs no change.
Errors on non-struct embed or name collision.
`e is T` returns bool (variant tag == T's index); `e as T` unwraps
to T or exit(1) on mismatch. Postfix, same precedence as `:` cast.
TK_IS / N_TYPETEST / N_TYPEASSERT appended at the tail of their
enums so every prior numeric value stays unchanged — the
990_selfhost wwdump-diff stays byte-clean.
Cgen mirrors the match-case slot-based load (tag at +0, value at
+8/+16), so an N_IDENT tagged-union local works just like a
match scrutinee. Selfhost cgen inlines the slot resolution
because the wwstage cgen drops sign bits on `*i32` output
parameters in this position.
Renames `errors.is` -> `errors.equal` (the only naming collision;
the existing comment already noted it shared shape with
strings.equal/bytes.equal).
