cstage+selfhost+test: full-element store for [N]str array literals (#21)

[N]str array literals wrote only the .ptr half of each element.
cstage used esz=16 from `lu->sub->size` and a single per-element
MOVQ → .len trailed uninitialized stack residue. Wwstage was worse:
primsize("str")=0 fell through to esz=8, so element i+1's ptr-MOVQ
clobbered element i's .len slot, scrambling everything.

Worker-18 sidestepped during #18 by rewriting array primer rows to
[N]i64.

cstage cgen.c N_ARRLIT TY_STR branch: emit AX → base+i*16 then
BX → base+i*16+8. Repeat-`...` path mirrored. type_isstr handles
TY_UNTYPED_STR + TY_NAMED-aliased-str.

Wwstage cgenstmt.ww: isstrel flag conditionally drives the two-MOVQ
store in both the per-element walk and the repeat fill. The dispatch
loop was refactored to unify FIELD/ellipsis branches via isellip,
cleaning up the duplicated arms.

Wwstage cgenutil.ww slotsize/letslotsize: TNAME-"str" element gets
esz=16, replacing the primsize=0 → 8B fallback. Without this the
frame collapsed to 24B for [3]str.

Slice (24B), struct, tuple, tagged element arrays have the same root
cause but distinct width/layout concerns — deferred to #35 per rob.

Test 711 (arrlit_str_full): 7 rows × 2 stages = 14 fixtures —
str_lens_3el, str_ptrs_3el, str_repeat_5el (TK_ELLIPSIS), bool_3el,
rune_3el, i32_3el, i64_3el. Rune relies on the pre-existing esz==4
→ MOVL path (incidental correctness); sibling slot types pinned as
regression nets.

Followups filed: #34 (wwstage cgindex truncate on [N]str bare-let
read side, surfaced by this fix), #35 (composite element types),
#36 (primsize-returns-0-default-to-8 cleanup).
This commit is contained in:
2026-05-16 10:38:23 +09:00
parent f906081c8c
commit cbb9fbbb65
7 changed files with 483 additions and 85 deletions

View File

@@ -0,0 +1,229 @@
/*
* 711_arrlit_str_full — `let xs: [N]str = [...]` writes BOTH halves
* of every element (task #21).
*
* Pre-fix: cgen's N_LET / N_ARRLIT branch dispatched its per-element
* store off a single esz / mop pair derived from `lu->sub->size`
* (cstage) or `primsize(elem.str)` (wwstage). Both fell through to a
* single MOVQ AX, off+i*esz(BP) for a str element — leaving the .len
* half (off+i*esz+8) as whatever stack residue the prologue's SUBQ
* happened to land on. Wwstage was worse: primsize("str") returns 0,
* so esz collapsed to 8, and the per-element stride was wrong too —
* element i+1's MOVQ overwrote what should have been element i's
* .len half.
*
* Fix: detect str-element arrays at letslotsize / slotsize / cgen
* dispatch and emit both halves per element — MOVQ AX, off+i*16(BP)
* for .ptr, MOVQ BX, off+i*16+8(BP) for .len. Symmetric across cstage
* cgen.c (N_LET / N_ARRLIT, type_isstr dispatch) and wwstage
* cgenstmt.ww + cgenutil.ww (slotsize / letslotsize TNAME-"str"
* special-case, cgenstmt isstrel branch). bool / rune / iN element
* arrays were never broken — their primitive store widths covered
* the full element — but they're pinned here as regressions so a
* future esz refactor can't quietly redo the slot-rounding gap.
*
* What this test pins (runtime only):
* - [3]str literal: every element's .len reads back correctly
* (pre-fix: zero or stack residue).
* - [3]str literal: every element's .ptr → first byte reads back
* correctly (the ptr half was always right; sanity).
* - [3]bool literal: regression-pin true / false / true.
* - [3]rune literal: regression-pin primitive size 4 element.
* - [3]i32 / [3]i64 literal: regression-pin primitive widths.
* - [5]str = ["x", ...] repeat marker: all 5 slots get full 16B
* stores (pre-fix: trailing slots' .len = zero).
*
* Slice / struct / tuple / tagged element arrays are NOT covered:
* the read side (cgindex of an [N]slice) has its own truncating-to-
* ptr bug, so an end-to-end repro surfaces sub-issues. Tracked as a
* follow-up.
*
* Asm byte-identity across stages is NOT diffed here: 995_self_rebuild
* covers the broader cross-stage drift surface, and the str / repeat
* rows produce identical MOVQ pairs across stages by construction.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>
static int
runwait(const char *cmd)
{
int rc = system(cmd);
if (rc == -1) return -1;
if (WIFEXITED(rc)) return WEXITSTATUS(rc);
return -1;
}
struct row { const char *label; const char *src; int want; };
static const struct row rows[] = {
/* 1. [3]str — every .len reads back correctly. Exit code is
* 100*a[0].len + 10*a[1].len + a[2].len = 100*2 + 10*6 + 1 = 261
* mod 256 = 5. Pre-fix: zero (all .len halves uninit). */
{ "str_lens_3el",
"fn main() i32 = {\n"
" let a: [3]str = [\"hi\", \"byebye\", \"x\"];\n"
" let p: i32 = a[0].len: i32;\n"
" let q: i32 = a[1].len: i32;\n"
" let r: i32 = a[2].len: i32;\n"
" return p * 100i32 + q * 10i32 + r;\n"
"};\n",
5 },
/* 2. [3]str — every .ptr is reachable. Reads element 0's first
* byte through `.ptr` to confirm the ptr half wasn't broken by
* the .len-half fix. 'h' (104) - 100 = 4. */
{ "str_ptrs_3el",
"fn main() i32 = {\n"
" let a: [3]str = [\"hi\", \"by\", \"x\"];\n"
" let p: *u8 = a[0].ptr;\n"
" let c: u8 = *p;\n"
" return (c: i32) - 100i32;\n"
"};\n",
4 },
/* 3. [5]str = ["x", ...] — repeat marker fills all 5 slots with
* a full 16B store, not just .ptr. Sum each .len: 5*1 = 5.
* Pre-fix: a[0].len = 1 from explicit init, a[1..4].len = stack
* residue (often 0, but unspecified). */
{ "str_repeat_5el",
"fn main() i32 = {\n"
" let a: [5]str = [\"x\"...];\n"
" let s: i32 = 0i32;\n"
" let i: i32 = 0;\n"
" for (i < 5) {\n"
" s += a[i].len: i32;\n"
" i += 1;\n"
" };\n"
" return s;\n"
"};\n",
5 },
/* 4. [3]bool — regression-pin. Pre-fix and post-fix: true/false/
* true with element width 1. Exit = 4*b[0] + 2*b[1] + b[2] =
* 4 + 0 + 1 = 5. */
{ "bool_3el_regression",
"fn main() i32 = {\n"
" let b: [3]bool = [true, false, true];\n"
" let s: i32 = 0i32;\n"
" if (b[0]) { s += 4i32; };\n"
" if (b[1]) { s += 2i32; };\n"
" if (b[2]) { s += 1i32; };\n"
" return s;\n"
"};\n",
5 },
/* 5. [3]rune — regression-pin primitive size 4. 'b' - 'a' = 1. */
{ "rune_3el_regression",
"fn main() i32 = {\n"
" let r: [3]rune = ['a', 'b', 'c'];\n"
" let v: rune = r[1];\n"
" return (v: i32) - 97i32;\n"
"};\n",
1 },
/* 6. [3]i32 — regression-pin primitive size 4. */
{ "i32_3el_regression",
"fn main() i32 = {\n"
" let a: [3]i32 = [10i32, 20i32, 30i32];\n"
" return a[0] + a[1] - a[2];\n"
"};\n",
0 },
/* 7. [3]i64 — regression-pin primitive size 8. Sum 1+2+3 = 6. */
{ "i64_3el_regression",
"fn main() i32 = {\n"
" let a: [3]i64 = [1i64, 2i64, 3i64];\n"
" return (a[0] + a[1] + a[2]): i32;\n"
"};\n",
6 },
};
static int
run_driver(const char *driver, const struct row *r, int i)
{
char src[64], tmpdir[64], cmd[1024];
snprintf(src, sizeof src, "/tmp/wcrarrs_%d_%d.ww", getpid(), i);
snprintf(tmpdir, sizeof tmpdir, "/tmp/wcrarrs_%d_d_%d", getpid(), i);
FILE *f = fopen(src, "wb");
if (!f) return -1;
fputs(r->src, f);
fclose(f);
mkdir(tmpdir, 0755);
snprintf(cmd, sizeof cmd, "cd %s && %s build %s",
tmpdir, driver, src);
if (runwait(cmd) != 0) {
fprintf(stderr, "row[%s]: build via %s failed\n",
r->label, driver);
unlink(src); rmdir(tmpdir);
return -1;
}
const char *base = strrchr(src, '/');
base = base ? base + 1 : src;
char outbin[128];
snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
char *dot = strrchr(outbin, '.');
if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
int got = runwait(outbin);
unlink(src); unlink(outbin); rmdir(tmpdir);
return got;
}
int
main(void)
{
const char *bin = getenv("BIN");
if (!bin) bin = "out/bin";
char absbin[512];
if (bin[0] != '/') {
char cwd[256];
if (getcwd(cwd, sizeof cwd) == NULL) return 1;
snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
bin = absbin;
}
char cdrv[640];
snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
char wdrv[640];
snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
struct { const char *name; const char *path; int gated_on_existence; }
drivers[] = {
{ "cstage", cdrv, 0 },
{ "wwstage", wdrv, 1 },
{ NULL, NULL, 0 },
};
int n = (int)(sizeof rows / sizeof rows[0]);
int total = 0, fail = 0;
for (int d = 0; drivers[d].name; d++) {
if (drivers[d].gated_on_existence
&& access(drivers[d].path, X_OK) != 0) {
fprintf(stderr, "arrlit_str_full: skip %s (no %s)\n",
drivers[d].name, drivers[d].path);
continue;
}
for (int i = 0; i < n; i++) {
int got = run_driver(drivers[d].path, &rows[i], i);
total++;
if (got != rows[i].want) {
fprintf(stderr,
"arrlit_str_full[%s][%s]: exit=%d want=%d\n",
drivers[d].name, rows[i].label,
got, rows[i].want);
fail++;
}
}
}
if (fail) {
fprintf(stderr,
"arrlit_str_full: %d/%d fixtures failed\n", fail, total);
return 1;
}
printf("arrlit_str_full: %d/%d ok\n", total, total);
return 0;
}