/* * 757_letbind_void_bang_void — wwstage slotsize recognises `void` as * zero-sized so `(void | !void)` (or any aliased equivalent) sizes its * tagged slot at tag + 0 = 8B rather than tag + 8 = 16B. Surfaced by * task #7's `fromutf8` (lib/strings/strings.ww), which let-binds the * `(void | utf8.invalid)` result of `utf8.validate` before matching. * * Pre-fix (#48 part-A): wwstage's slotsize (selfhost/cmd/wcc/cgenutil.ww) * lacked a `void`-as-0B case — primsize("void")==0 failed the `> 0` * guard and fell through alias/struct lookup to the catch-all `return 8`. * Aliased `!void` recursed into the same TNAME("void") branch with the * same fallthrough. The N_TTAGGED branch then computed maxsz=8, slot = * tag + pad(8) = 16. cglet routes the let-init through cgwidentaggedstore * which sizes its AX→+0 / DX→+8 ABI receive by slot size — so wwstage * emitted a phantom `MOVQ DX, off+8` spill, picking up the callee's * stale DX (validate's bare `return;` doesn't zero it). Frame size * diverged by 16B; every downstream offset shifted; bootstrap byte- * identity broke as soon as any caller let-bound a `(void | !void)`. * * Cstage was already correct: cmd/wcc/type.c:46 sets `ty_void.size = 0`, * cmd/wcc/check.c:432 reads it via `maxsz = 0; vsz = 0; size = 8 + 0`. * * Fix (#48, wwstage-only per rule 10): two narrow additions to * `slotsize` in selfhost/cmd/wcc/cgenutil.ww — * 1. N_TBANG case at the top: recurse on .lhs, mirroring cstage * resolve_type N_TBANG which copies the inner type's size. * 2. N_TNAME branch: `streq(nm, "void") => 0` before primsize, so * the zero-size lands without the prim-pad-to-8 contract firing. * * What this test pins: * - Asm byte-identity between cstage and wwstage for `(void | invalid)` * let-bind through match, where invalid = !void (utf8.invalid shape). * - Runtime: both arms return their expected exit code. * - Frame size matches between stages (no $48 vs $32 drift in `foo`). */ #include #include #include #include #include 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. The canonical fromutf8 shape: let-bind `(void | invalid)`, * match on it, return through both arms. validate always returns * the void variant here. */ { "letbind_void_arm", "type invalid = !void;\n" "fn validate() (void | invalid) = { return; };\n" "fn main() i32 = {\n" " let v: (void | invalid) = validate();\n" " match (v) {\n" " case void => return 7;\n" " case let e: invalid => return 9;\n" " };\n" " return 0;\n" "};\n", 7 }, /* 2. invalid arm — validate returns the !void variant. Pre-fix * the phantom payload-spill picked up validate's stale DX; post- * fix only the tag word lands in the slot. */ { "letbind_invalid_arm", "type invalid = !void;\n" "fn validate() (void | invalid) = {\n" " let e: invalid; return e;\n" "};\n" "fn main() i32 = {\n" " let v: (void | invalid) = validate();\n" " match (v) {\n" " case void => return 7;\n" " case let e: invalid => return 9;\n" " };\n" " return 0;\n" "};\n", 9 }, /* 3. Natural fromutf8 form: success-arm lifts a plain str into * `(str | invalid)`. Pre-fix the let-bind's bogus 16B slot * pushed every downstream offset 8B further from BP; the lift * itself (str → tagged-return ABI) was already correct, but * frame-id drift broke byte-identity. */ { "fromutf8_natural_match", "type invalid = !void;\n" "fn validate(s: str) (void | invalid) = { return; };\n" "fn fromutf8(s: str) (str | invalid) = {\n" " let v: (void | invalid) = validate(s);\n" " match (v) {\n" " case void => return s;\n" " case let e: invalid => return e;\n" " };\n" " let e: invalid; return e;\n" "};\n" "fn main() i32 = {\n" " match (fromutf8(\"hi\")) {\n" " case let s: str => return s.len: i32;\n" " case invalid => return -1;\n" " };\n" " return 0;\n" "};\n", 2 }, }; static int run_driver(const char *driver, const struct row *r, int i) { char tmpdir[64], src[128], outbin[128], rmcmd[160], cmd[1024]; snprintf(tmpdir, sizeof tmpdir, "/tmp/wclbvv_%d_d_%d", getpid(), i); mkdir(tmpdir, 0755); snprintf(src, sizeof src, "%s/wclbvv_%d_%d.ww", tmpdir, getpid(), i); snprintf(outbin, sizeof outbin, "%s/wclbvv_%d_%d", tmpdir, getpid(), i); snprintf(rmcmd, sizeof rmcmd, "rm -rf %s", tmpdir); FILE *f = fopen(src, "wb"); if (!f) { runwait(rmcmd); return -1; } fputs(r->src, f); fclose(f); snprintf(cmd, sizeof cmd, "%s build -o %s %s", driver, outbin, src); if (runwait(cmd) != 0) { fprintf(stderr, "row[%s]: build via %s failed\n", r->label, driver); runwait(rmcmd); return -1; } int got = runwait(outbin); runwait(rmcmd); return got; } /* asm_byte_identical — pin frame size + spill layout by diffing the * w6c vs w6c_ww text output. #48 part-A's whole point is that * wwstage's slot stops bloating for the (void | !void) shape, so the * bytes must match. */ static int asm_byte_identical(const char *bin, const struct row *r, int i) { char src[64], cs[64], ws[64], cmd[1024]; snprintf(src, sizeof src, "/tmp/wclbvv_asm_%d_%d.ww", getpid(), i); snprintf(cs, sizeof cs, "/tmp/wclbvv_asm_%d_%d_c.s", getpid(), i); snprintf(ws, sizeof ws, "/tmp/wclbvv_asm_%d_%d_w.s", getpid(), i); FILE *f = fopen(src, "wb"); if (!f) return -1; fputs(r->src, f); fclose(f); snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src); if (runwait(cmd) != 0) { fprintf(stderr, "row[%s]: w6c errored\n", r->label); unlink(src); return -1; } snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null", bin, ws, src); if (runwait(cmd) != 0) { fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label); unlink(src); unlink(cs); return -1; } FILE *fc = fopen(cs, "rb"); FILE *fw = fopen(ws, "rb"); int rc = 0; if (!fc || !fw) { rc = -1; } else { for (;;) { int a = fgetc(fc); int b = fgetc(fw); if (a != b) { rc = -1; break; } if (a == EOF) break; } } if (fc) fclose(fc); if (fw) fclose(fw); if (rc != 0) fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n", r->label); unlink(src); unlink(cs); unlink(ws); return rc; } 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, "letbind_void_bang_void: 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, "letbind_void_bang_void[%s][%s]: exit=%d want=%d\n", drivers[d].name, rows[i].label, got, rows[i].want); fail++; } } } if (access(wdrv, X_OK) == 0) { for (int i = 0; i < n; i++) { total++; if (asm_byte_identical(bin, &rows[i], i) != 0) fail++; } } if (fail) { fprintf(stderr, "letbind_void_bang_void: %d/%d fixtures failed\n", fail, total); return 1; } printf("letbind_void_bang_void: %d/%d ok\n", total, total); return 0; }