Mirror of 548547a in the wwstage cgen.
cgexpr learns N_SLICE: `base[lo:hi]` leaves (AX=ptr, BX=len, CX=cap)
so callers (return, arg push, reassignment, let init for fn-returning-
slice / slice-ident) share one triple ABI. Without this, the existing
let-init that just forwards (AX,BX,CX) to the slot was silently storing
junk on a base[lo:hi] rhs.
cgassign gains a slice branch parallel to str: for a local slice ident
lhs, store all three halves to off+0/+8/+16; for a slice global, stash
CX into DI before LEAQ-ing the symbol address into CX (CX is both the
incoming cap and the LEAQ scratch), then store AX/BX/DI at +0/+8/+16.
N_IDENT slice-local triple load was already in place from the earlier
selfhost port; only the cgexpr and cgassign halves needed adding.
Byte-identical to C w6c on the corpus — make test 26/26, 994_w6c_ww
passes on 10 inputs, 990_selfhost + 995_self_rebuild reach fixed point.
Lexer: `lexnum` now parses the digit/exponent tail into an f64 via a
new `parsef64` (decimal-only, integer-arith driver + pow-10 multiply,
no strtod). The IEEE bits are also stashed in tok.uval via pointer
reinterpret so cgen consumers stay integer-only.
Parser: TK_FLOAT → N_FLOATLIT, carrying both fval and uval. Parser
state grows curfval to plumb the lexer's f64 through refill.
cgen:
- cgfloatlit reads n.uval and materialises X0 via the standard
MOVQ-PUSHQ-MOVSD-ADDQ trampoline.
- cglet, cgident, cgassign learn float-typed branches: MOVSS/MOVSD
for locals; LEAQ-indirect MOVSS/MOVSD for globals.
- cgbin handles ADDSD/SUBSD/MULSD/DIVSD (+ SS variants) and
UCOMISD/UCOMISS-based comparisons. cgun handles float negate
via the `0 - X0` shape C cgen uses.
- cgcast routes int↔float and f32↔f64 through CVTSI2SD/CVTTSD2SI/
CVTSD2SS/CVTSS2SD and their SS twins.
- cgcall + pushargsrev push float args via SUBQ+MOVSD and pop into
the X0..X7 stream, tracked by a per-class counter alongside the
int DI..R9 stream. cgfnparams loads float params from the same
stream.
- emitletdataw bakes FLOATLIT init bits into DATAW (4B for f32,
8B for f64).
Tests: smoke programs (literal init, reassign, arithmetic, fn args/
returns, casts) produce byte-identical asm through `w6c` and
`wwdump_ww -c`, and the resulting binary exits with the same value
whether compiled by the C or wwstage toolchain. Full `make test` is
26/26 and `make bootstrap` still reaches its byte-identical
ww2==ww3==ww4 fixed point.
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.
Mirror the C cgen's N_IDENT load fallback. Reads of a top-level
scalar `let` now emit `MOVQ name(SB), AX` (RIP-relative) instead
of silently dropping. Truly undefined names still fall through to
the silent return, matching the pre-existing defensive behaviour;
the C side's broader unconditional fallback is intentionally not
mirrored here so typos surface as nothing-emitted rather than a
link-time stub.
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.
Cascades the four enum kinds through every signature and local that
holds one of their values, then removes the type_assignable /
unify_arith relaxation that previously let bare i32 mix with the
named enum types.
Signature updates:
- kwlookup() now returns `tkind` (not i32); tokname() takes `tkind`
- accepttok / expecttok / bprec / isassignop take `tkind`
- parsearglist's closekind is `tkind`
- newtype / prim take `tykind`; scopedefine takes `skind`
- newnode / nkname take `nkind`
Struct fields:
- tok.kind is `tkind`; parser.curkind is `tkind`
- node.kind is `nkind`; node.op is `tkind`
- tinfo.kind is `tykind`; sym.skind is `skind`
Locals holding kinds across lex/parse/check/cgen are now typed with
their enum, including sentinel patterns like `let lkind: nkind =
nkind.N_NONE; if (...) lkind = tn.kind;`.
The selfhost cgen had a load-width bug exposed by this: fieldsize()
fell back to 8 bytes for any TNAME that wasn't a struct or primitive.
For a tkind-typed field that gave `MOVQ (BX), AX` instead of `MOVL`,
diverging from the C cgen on tok.kind / parser.curkind / etc. Two
fixes:
- fieldsize now consults the enum registry and returns the storage
type's size (4 for `enum i32`)
- collectenums runs before collectstructs in cgfile so the registry
is populated when registerstruct asks for field sizes
All 22 tests stay green; 990/993/995 byte-identity probes pass with
the strict typing in place.
`type tkind = enum i32 { TK_NONE = 0, TK_EOF = 1, ... TK_LAST = 86 }`
replaces the 87-line `def TK_*: i32 = N` cluster in lib/ww/lex/tok.ww.
Numeric values explicit so 990_selfhost's byte-diff against the C-side
`Tkind` enum still passes.
All ~270 reference sites in lib/ww and selfhost/cmd/{wcc,wwdump}
sed-renamed `TK_X` → `tkind.TK_X`. Struct fields (`tok.kind`,
`parser.curkind`) intentionally kept as `i32` — making them `tkind`
shifted some byte-positions in the cgen output and broke 990/993/995
byte-identity probes without an obvious win.
To make the rename non-cascading on every signature, type_assignable
and unify_arith in cmd/wcc/check+type relax to allow enum ↔ int
mixing when storage matches (a `tkind` value flows into an `i32`
slot and vice versa, no explicit cast). This deviates from Hare's
strict enum semantics; doc'd as an explicit pragmatic relaxation
for the compiler's internal enum-shaped kinds. External user code
can still get the type-safety benefit if they declare their
parameters with the enum type.
combined.ww files regenerated by ww build.
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.
`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.
C-cgen-side nullable folding landed in f4efaac. This commit catches
the selfhost cgen up so a wwstage-compiled binary produces the same
ABI for `(*T | void)`.
- cgenutil: isnullabletype(), nullableptrtag() helpers shaped to
the selfhost cgen's AST-only world view (it doesn't carry a Type
with a .nullable flag — it walks N_TTAGGED node lists). slotsize
returns 8 for nullable.
- cgenexpr cgmatch: nullable arm uses pointer-vs-null discriminator
and binds only the *T case (void has size 0).
- cgenstmt cglet: nullable target spills only AX (no tag word, no
value-word DX/CX).
- cgenstmt cgreturn: nullable return passes AX through with no
shuffle; bare `return;` emits AX = 0 (void encoding).
Verified end-to-end: a fn returning `(*i32 | void)` compiled by the
wwstage cgen produces the same exit code as the C-cgen build. The
995 fixed-point gate stays green — no selfhost source uses nullable
yet, so the existing tagged paths are still byte-identical.
Selfhost parser (lib/ww/parse/expr.ww) recognises postfix `?` and
`!` at the same level as `as`/`is`/`:`. Selfhost cgen
(selfhost/cmd/wcc/cgenexpr.ww) emits matching code: cmp AX against
the success tag (0 in legacy mode), branch over the propagate /
abort path, then unwrap (DX → AX, CX → BX for str). Mirrors the C
cgen but without the tag-remap loop — none of the selfhost code
that uses `?` today needs cross-shape remapping.
lib/ww/lex/lex.ww \\x escape handling switched from 5-line match
blocks to one-liners: ascii.digitval(c: rune)!. Both digits are
already validated by isxdigit above; the void variant is
unreachable, so `!` collapses correctly. 995 fixed-point gate
verifies the selfhost cgen produces the same `!` codegen as C cgen.
`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.
`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).
