rt_malloc was a bare mmap-per-call wrapper: every allocation, even a
32-72B AST/symbol node, consumed a page-rounded 4KB region and was
never freed. w6a/w6c emit ~4 such nodes per .s line, so assembling a
145K-line file burned ~625K pages (~2.5GB); test 995's 5 concurrent
self-rebuilds then OOM'd. The defect is linear and str-independent --
the str->24B codegen merely enlarged .s files past the cliff.
Replace it with the no-free SUBSET of Hare's allocator
(ref/hare/rt/malloc.ha): 2MiB chunk-bump (CHUNKSZ malloc.ha:24, ALIGN
malloc.ha:14), oversized (>CHUNKSZ) requests direct-mmap'd. The
bin/freelist/META machinery exists only to support free, which ww does
not have, so it is omitted. Policy lives in rt/malloc.ww; the raw mmap
primitive stays in rt/alloc.s as rt_segmalloc -- Hare's malloc/segmalloc
split.
rt_free becomes a documented no-op (os.free re-exports it for the public
API, so the symbol must stay); rt/ensure.ww drops its now-impossible
reclaim. Zero-init is preserved: the bump never reuses memory, so every
byte is fresh MAP_ANONYMOUS-zeroed.
w6a_ww on a 145K-line .s: 2165MB -> 28MB (~glibc parity, C w6a 24MB).
.o output byte-identical; both stages emit identical asm. make test
134/134.
Hare's canonical runtime allocator is rt::malloc with linker symbol
rt.malloc (ref/hare/rt/malloc.ha:27,78). ww kept the dot→underscore
Plan 9 convention (CLAUDE.md rule 4) so the linker symbol becomes
rt_malloc; the lib/rt exported function name becomes malloc; ww
callers say rt.malloc(...).
The language builtin keyword stays `alloc(T)!` — unchanged from Hare
(ref/hare/hare/lex/token.ha:21 ltok::ALLOC, parse/expr.ha:398
builtin()). The rename only touches the lowered linker symbol and the
exported function name behind it; the user-facing syntax for
heap-allocation is identical to Hare.
Surface:
- rt/alloc.s: TEXT rt_alloc → TEXT rt_malloc, labels updated
- lib/rt/malloc.ww: @symbol("rt_malloc") fn malloc(...) (was rt_alloc/alloc)
- rt/ensure.ww: local FFI decl + call site updated to malloc; `!` dropped
on the direct FFI call (rt_malloc returns *void, not a tagged union)
- 18 .ww callers: rt.alloc(...) → rt.malloc(...)
- cstage cmd/wcc/check.c + wwstage selfhost/cmd/wcc/check.ww
alloc-builtin suppression gate routes through ffi_resolve("malloc")
for the lowering; the user-shadow check still keys on the BUILTIN
KEYWORD "alloc" since that is what `alloc(...)` parses as. Adding
"malloc" to the user-shadow check was unnecessary and was reverted
during pre-commit review.
- cstage cmd/w6c/cgen.c: 2× ffi_resolve("alloc") → ffi_resolve("malloc")
- wwstage cgenexpr/cgenstmt: 2× ffiresolve(c, "alloc") → ffiresolve(c, "malloc")
- Test fixtures (700_e2e, 758_cgalloc_str_field, 990_selfhost, 992_w6l_ww,
selfhost/test/tagged_ptr_ret.ww): updated inline ww sources to the new
decl + call form
This is commit 2 of 3 in the lib/rt extraction (#38). Commit 3 closes
the OOM contract — return type becomes nullable *void and the builtin
lowering null-checks + propagates nomem.
Verified 132/132 + 995_self_rebuild byte-identity (5 wwstage tools
round-trip identical) + make clean cold rebuild.
Per Hare convention, alloc is a typed builtin that returns a tagged
union carrying nomem as the OOM variant. Callers spell their policy:
`alloc(T)!` aborts on OOM (the old behavior), `alloc(T)?` propagates
when the enclosing fn already returns nomem.
cstage: check builds TY_TAGGED{*T | nomem} (or {[]T | nomem}); cgen
emits AX=tag, DX=ptr per the general tagged-return ABI (the (*T|!void)
nullable-ptr fold gated in ea76ee4 keeps this clean). wwstage cgalloc
mirrors. rt/alloc.s zeroes AX on syscall error so the builtin's null
check sees a clean 0 instead of mmap's -errno leaking through as a
poisoned pointer.
Migration: 3 `!` sites in test/wcc/700_e2e.c, 1 `!` site in
rt/ensure.ww (preserves the pre-existing sizeof bug tracked by #27),
1 `?` site in selfhost/test/tagged_ptr_ret.ww (allocbox exercises
real `?` propagation against a (*T | nomem) return).
130/130 tests green, 994_w6c_ww + 995_self_rebuild stage byte-identity
preserved. Follow-ups #31 (wwstage checkletassign leniency), #32
(wwstage slice-form gap), #33 (tagged_ptr_ret.ww make-test wiring).
