/* * 841_match_global_field — match on a tagged-union struct-FIELD of a * GLOBAL (module-level) VALUE struct: `match (g.t)`, g a `let g: box`. * Task #29. * * GATE-BLIND both-wrong regression from M1 (#25). M1 added an in-place * N_DOT match arm that points the dispatch slot at base.off + * field.offset, computing base.off via localfind. For a LOCAL base that * is the field's true frame slot ($32 in-place, correct). For a GLOBAL * base localfind returns its 0/not-found sentinel, so 0 + field.offset * lands in the saved-BP / return-addr region (BP+0/BP+8): both stages * emit `MOVQ (BP),AX` and read garbage. Both stages were identical-wrong * (byte-id GREEN), so only the RUNTIME oracle catches it — pre-fix * match(g.t) returns 213 instead of 42. * * Fix (both stages, rule 10): gate the in-place arm on a confirmed-LOCAL * base. A base is GLOBAL iff localfind(base)==0 && let_islet(base) * (cstage) / isletvar(c, base) (wwstage) — the same idiom cstage uses at * cgen.c:2000 (also 4707/4730/5393). A global base falls THROUGH to the * existing spill `else`, which cgexprs the scrutinee and resolves g(SB) * correctly. M1's LOCAL in-place path is unchanged (row (d) pins it). * * Rows pin the RUNTIME exit code on BOTH driver stages (cstage + * wwstage) — the discriminator is the value, not byte-id, since both * stages were identical-wrong. A cstage-vs-wwstage asm byte-identity * check is kept per row so the symmetric (rule-10) property stays pinned * after the guard lands in both stages. * (a) global VALUE-struct int-variant field [spill, g(SB)] * (b) global field bool->int payload remap [1-word variant] * (c) global field str-payload (24B box) [3-word variant] * (d) local VALUE-struct field, in place [M1 regression guard] */ #include #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[] = { /* (a) GLOBAL value struct, field set to the int variant in main, * matched. Pre-fix the in-place arm read BP+0 (213); post-fix the * spill path resolves g(SB) and returns 42. */ { "global_field_int", "package main;\n" "type box = struct { t: (int | bool), n: int };\n" "let g: box = box { t = 0, n = 5 };\n" "fn main() i32 = {\n" " g.t = 42;\n" " match (g.t) {\n" " case let n: int => return n: i32;\n" " case bool => return 1;\n" " };\n" "};\n", 42 }, /* (b) GLOBAL field reassigned, then matched; the int arm also reads * the sibling field g.n to prove the surrounding global is * undisturbed. Returns 7 + 5 = 12. The static initializer uses the * ZERO payload (t = 0): a nonzero tagged-field payload in a static * struct initializer trips a SEPARATE, deferred static-init DATA * divergence (task #19/#30 — wwstage drops the payload word to 0, * cstage emits it) that is orthogonal to the #29 match-cgen path * exercised here; a zero payload is byte-identical across stages. */ { "global_field_reassign_remap", "package main;\n" "type box = struct { t: (int | bool), n: int };\n" "let g: box = box { t = 0, n = 5 };\n" "fn main() i32 = {\n" " g.t = 7;\n" " match (g.t) {\n" " case let n: int => return (n + g.n): i32;\n" " case bool => return 1;\n" " };\n" "};\n", 12 }, /* (c) GLOBAL field, 24B str-payload variant (tag@+0, .ptr@+8, * .len@+16). Returns len("hello") = 5. */ { "global_field_str_payload_24B", "package main;\n" "type box = struct { t: (str | int), n: int };\n" "let g: box = box { t = 0, n = 5 };\n" "fn main() i32 = {\n" " g.t = \"hello\";\n" " match (g.t) {\n" " case let s: str => return len(s): i32;\n" " case int => return 99;\n" " };\n" "};\n", 5 }, /* (d) regression guard: a LOCAL value-struct field still reads in * place (M1's $32 path stays). Returns 42. */ { "local_field_inplace_guard", "package main;\n" "type box = struct { t: (int | bool), n: int };\n" "fn main() i32 = {\n" " let b: box = box { t = 0, n = 5 };\n" " b.t = 42;\n" " match (b.t) {\n" " case let n: int => return n: i32;\n" " case bool => return 1;\n" " };\n" "};\n", 42 }, }; 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/wcmgf_%d_%d.ww", getpid(), i); snprintf(tmpdir, sizeof tmpdir, "/tmp/wcmgf_%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; } /* asm_byte_identical — the guard lands in BOTH stages, so cstage vs * wwstage text output must stay byte-for-byte identical on every row. */ 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/wcmgf_asm_%d_%d.ww", getpid(), i); snprintf(cs, sizeof cs, "/tmp/wcmgf_asm_%d_%d_c.s", getpid(), i); snprintf(ws, sizeof ws, "/tmp/wcmgf_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, "match_global_field: 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, "match_global_field[%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, "match_global_field: %d/%d fixtures failed\n", fail, total); return 1; } printf("match_global_field: %d/%d ok\n", total, total); return 0; }