w6c+wwstage: source sub-8 value-struct ABI-size from tinfo.size at zero-init+DATAW (#254)
wwstage conflated SLOT-size (round-to-8, for frame) with ABI-size (true)
for a nested value-struct. A nested value-struct field is sized via
fieldsize() (TY_STRUCT -> ti.slotsize = 8), poisoning structabisize and
registerstruct si.totsize to 8 for a struct whose true ABI size is 4.
Two emission sites then over-sized, both SILENT cs!=ww divergences:
D1 (local, cgenstmt.ww cglet): zsz = structabisize = 8 hit the
`zsz == 8` zero arm (#213) -> a stray `MOVQ $0, off(BP)` cstage
never emits (ABI 4 is sub-8 -> left uninit per the shared no-rhs
zero-init policy).
D2 (global, cgen.ww emitletdataw): the struct zero arm wrote
letemitsize/si.totsize = 8 DATAW bytes; cstage cg_let_emit_size
returns u->size = 4.
Fix sources the zero-init extent from the type table's tinfo.size
(peeling TY_NAMED) at both sites — the same value cstage reads
(cgen.c:8397 / :978). fieldsize / registerstruct / frame slot-padding
stay UNTOUCHED: moving the fix into the size helpers would shift
nested-struct field offsets and re-diverge other byte-id. Pure
wwstage-align-down; cstage cmd/w6c/cgen.c unchanged.
Test 949_valstruct_subsize_run: D1 local + D2 global over ABI sizes
1/2/4 (the whole sub-8 / non-8-multiple class), each cstage-run +
cs==ww .s byte-id; plus a >8 (16B) local+global NEGATIVE control
proving the fix didn't disable legitimate multi-word zero-init.
Regen w6c + wwdump main.combined.ww (cgen is compiler-imported, #110).
This commit is contained in:
255
test/wcc/949_valstruct_subsize_run.c
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255
test/wcc/949_valstruct_subsize_run.c
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@@ -0,0 +1,255 @@
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/*
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* 949_valstruct_subsize_run — runtime + byte-id net for #254: a sub-8
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* (non-8-multiple) nested value-struct must size its zero-init extent
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* from the type table's natural ABI size (cstage lu->size), NOT the
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* slot-padded register-struct width.
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*
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* Root: wwstage conflated SLOT-size (round-to-8, for frame layout) with
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* ABI-size (true). A nested value-struct field was sized via fieldsize()
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* (cgenutil.ww TY_STRUCT -> ti.slotsize = 8), poisoning structabisize +
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* registerstruct si.totsize to 8 for a struct whose true ABI size is 4.
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* Two emission sites then over-sized:
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* D1 (local): cglet zsz = structabisize = 8 hit the `zsz == 8` zero
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* arm (cgenstmt.ww #213) -> a stray `MOVQ $0, off(BP)` that cstage
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* (ABI 4 is sub-8 -> left uninit per the shared no-rhs policy)
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* never emits.
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* D2 (global): emitletdataw struct arm wrote si.totsize = 8 zero bytes
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* of DATAW; cstage cg_let_emit_size returns u->size = 4.
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* Both were SILENT cs!=ww divergences (gate-blind: a standalone wwstage
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* is self-consistent; only the cs==ww .s cmp catches it).
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*
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* Fix (rule-13 SSoT): both sites source the extent from tinfo.size
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* (peeling TY_NAMED), the same value cstage reads. fieldsize /
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* registerstruct / frame slot-padding stay UNTOUCHED — moving the fix
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* into the size helpers would shift nested-struct field offsets and
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* re-diverge other byte-id.
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*
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* Rows cover the whole sub-8 class (ABI size 1/2/4) in both the local
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* (D1) and global (D2) emission contexts, plus a >8 NEGATIVE control
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* proving the fix didn't disable legitimate multi-word zero-init. Each
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* row: cstage `ww build` + run for the exit code (correctness) AND
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* w6c vs w6c_ww `.s` cmp for rule-10 byte-id (the silent-divergence net).
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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static int
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runwait(const char *cmd)
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{
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int rc = system(cmd);
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if (rc == -1) return -1;
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if (WIFEXITED(rc)) return WEXITSTATUS(rc);
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return -1;
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}
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struct row { const char *label; const char *src; int want_exit; };
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static const struct row rows[] = {
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/* D1 local, ABI size 4 (inner {[4]u8}). Pre-fix wwstage emitted a
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* stray MOVQ $0 cstage didn't -> .s differ. Write+read a byte so
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* the exit is deterministic (sub-8 is left uninit by BOTH stages,
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* matching cstage's no-rhs policy). */
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{ "d1_local_4",
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"package main;\n"
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"type inner = struct { m: [4]u8 };\n"
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"type outv = struct { i: inner };\n"
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"export fn main() i32 = {\n"
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" let o: outv;\n"
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" o.i.m[0] = 66u8;\n"
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" return o.i.m[0]: i32;\n"
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"};\n", 66 },
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/* D1 local, ABI size 2 ([2]u8). */
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{ "d1_local_2",
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"package main;\n"
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"type inner = struct { m: [2]u8 };\n"
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"type outv = struct { i: inner };\n"
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"export fn main() i32 = {\n"
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" let o: outv;\n"
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" o.i.m[1] = 55u8;\n"
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" return o.i.m[1]: i32;\n"
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"};\n", 55 },
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/* D1 local, ABI size 1 ([1]u8) — the tightest sub-8 case. */
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{ "d1_local_1",
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"package main;\n"
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"type inner = struct { m: [1]u8 };\n"
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"type outv = struct { i: inner };\n"
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"export fn main() i32 = {\n"
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" let o: outv;\n"
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" o.i.m[0] = 44u8;\n"
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" return o.i.m[0]: i32;\n"
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"};\n", 44 },
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/* D2 global, ABI size 4. Pre-fix wwstage emitted DATAW of 8 zero
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* bytes vs cstage's 4 -> .s differ. */
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{ "d2_global_4",
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"package main;\n"
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"type inner = struct { m: [4]u8 };\n"
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"type outv = struct { i: inner };\n"
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"let g: outv;\n"
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"export fn main() i32 = {\n"
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" g.i.m[0] = 66u8;\n"
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" return g.i.m[0]: i32;\n"
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"};\n", 66 },
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/* D2 global, ABI size 2. */
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{ "d2_global_2",
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"package main;\n"
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"type inner = struct { m: [2]u8 };\n"
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"type outv = struct { i: inner };\n"
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"let g: outv;\n"
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"export fn main() i32 = {\n"
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" g.i.m[1] = 55u8;\n"
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" return g.i.m[1]: i32;\n"
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"};\n", 55 },
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/* D2 global, ABI size 1. */
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{ "d2_global_1",
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"package main;\n"
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"type inner = struct { m: [1]u8 };\n"
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"type outv = struct { i: inner };\n"
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"let g: outv;\n"
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"export fn main() i32 = {\n"
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" g.i.m[0] = 44u8;\n"
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" return g.i.m[0]: i32;\n"
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"};\n", 44 },
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/* NEGATIVE control — a >8 (multi-word) value-struct still zero-
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* inits. Read an UNWRITTEN byte: a working multi-word zero-init
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* fill makes it 0. If the fix had wrongly suppressed the >8 zero
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* arm, this would read stack garbage (and byte-id would diff
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* against the still-zeroing cstage). Local + global both proven. */
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{ "ctl_local_16",
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"package main;\n"
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"type inner = struct { m: [16]u8 };\n"
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"type outv = struct { i: inner };\n"
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"export fn main() i32 = {\n"
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" let o: outv;\n"
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" return o.i.m[7]: i32;\n"
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"};\n", 0 },
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{ "ctl_global_16",
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"package main;\n"
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"type inner = struct { m: [16]u8 };\n"
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"type outv = struct { i: inner };\n"
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"let g: outv;\n"
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"export fn main() i32 = {\n"
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" return g.i.m[7]: i32;\n"
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"};\n", 0 },
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{ NULL, NULL, 0 }
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};
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static int
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slurp_eq(const char *a, const char *b)
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{
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FILE *fa = fopen(a, "rb");
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FILE *fb = fopen(b, "rb");
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if (!fa || !fb) { if (fa) fclose(fa); if (fb) fclose(fb); return -1; }
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int rc = 0;
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for (;;) {
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int ca = fgetc(fa);
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int cb = fgetc(fb);
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if (ca != cb) { rc = -1; break; }
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if (ca == EOF) break;
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}
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fclose(fa); fclose(fb);
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return rc;
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}
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int
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main(void)
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{
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const char *bin = getenv("BIN");
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if (!bin) bin = "out/bin";
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char absbin[1024];
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if (bin[0] != '/') {
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char cwd[1024];
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if (getcwd(cwd, sizeof cwd) == NULL) return 1;
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snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
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bin = absbin;
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}
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char w6c[1100], w6c_ww[1100];
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snprintf(w6c, sizeof w6c, "%s/w6c", bin);
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snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
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if (access(w6c_ww, X_OK) != 0) {
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fprintf(stderr, "valstruct_subsize: w6c_ww missing — cannot run "
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"the cs==ww byte-id gate (the whole point of this test)\n");
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return 1;
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}
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int n = 0, fail = 0;
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for (int i = 0; rows[i].src; i++, n++) {
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char src[64];
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snprintf(src, sizeof src, "/tmp/wwvss_%d_%d.ww", getpid(), i);
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FILE *f = fopen(src, "wb");
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if (f == NULL) { fail++; continue; }
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fputs(rows[i].src, f);
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fclose(f);
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char tmpdir[64];
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snprintf(tmpdir, sizeof tmpdir, "/tmp/wwvss_%d_d_%d",
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getpid(), i);
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mkdir(tmpdir, 0755);
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char cmd[2048];
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snprintf(cmd, sizeof cmd, "cd %s && %s/ww build %s",
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tmpdir, bin, src);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "row[%s]: cstage build failed\n",
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rows[i].label);
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fail++;
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unlink(src); rmdir(tmpdir);
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continue;
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}
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char outbin[128];
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const char *base = strrchr(src, '/');
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base = base ? base + 1 : src;
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snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
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char *dot = strrchr(outbin, '.');
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if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
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int got = runwait(outbin);
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if (got != rows[i].want_exit) {
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fprintf(stderr, "row[%s]: cstage exit %d, want %d\n",
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rows[i].label, got, rows[i].want_exit);
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fail++;
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}
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unlink(outbin); rmdir(tmpdir);
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char cs_s[64], ws_s[64];
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snprintf(cs_s, sizeof cs_s, "/tmp/wwvss_%d_%d_cs.s",
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getpid(), i);
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snprintf(ws_s, sizeof ws_s, "/tmp/wwvss_%d_%d_ww.s",
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getpid(), i);
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snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
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w6c, cs_s, src);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "row[%s]: w6c failed\n", rows[i].label);
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fail++; unlink(src); continue;
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}
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snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null",
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w6c_ww, ws_s, src);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "row[%s]: w6c_ww failed\n",
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rows[i].label);
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fail++; unlink(src); unlink(cs_s); continue;
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}
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if (slurp_eq(cs_s, ws_s) != 0) {
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fprintf(stderr,
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"row[%s]: cstage/wwstage .s DIFFER (rule-10 "
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"byte-id violation)\n", rows[i].label);
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fail++;
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}
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unlink(src); unlink(cs_s); unlink(ws_s);
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}
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if (fail) {
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fprintf(stderr, "%d/%d valstruct-subsize tests failed\n",
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fail, n);
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return 1;
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}
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printf("valstruct_subsize: %d/%d ok (cstage run + cs==ww byte-id)\n",
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n, n);
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return 0;
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}
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