/* * 734_struct_modshadow — sentinel for the trio leaf-name pattern's * 5th leaf: wwstage's structlookup. Pins bare-leaf `*S` field access * to a same-module-first walk so the load picks the caller's own * `S` (correct field offset / totsize) rather than another module's * same-leaf-name `S` sitting at the head of c.structs. * * Pre-fix wwstage's `structlookup` (selfhost/cmd/wcc/cgenutil.ww) * walked c.structs head-first by sname, returning the FIRST match. * The cgdot `*struct` field-load branch handed it `inner.str` (the * bare leaf from a parsed N_TPTR whose inner is N_TNAME) and the * head-pick silently emitted the wrong-module field offset — a * displacement against BX that loaded whatever the colliding-module * struct happened to align there. Silent miscompile, not byte-id: * cstage's resolve_typename uses scope_lookup_prefer(cur, cur_mod, * leaf) so check.c already binds the correct Type, and cgen.c reads * fi.foff off the typed Sym — cs vs ws asm diverged on every bare- * leaf collision but no in-tree corpus declares two same-leaf * structs, so 995 stayed green and the latent miscompile only * surfaces once a stdlib port introduces the collision (same shape * as #4a enumlookup surfacing post-strings). * * Trio's structural close per task #4 leaves: structlookup grows a * same-module-first walk before the head-walk fallback, mirroring * aliaslookup (#27), fnparamslookupmod (#28), fnretlookupmod (#31) * and enumlookup (#4a). NO structlookupmod variant: the consumer * surface for `pkg.S` is fully captured by the parser collapsing * dotted N_TNAME into a single str with embedded `.`, which routes * through structlookup's existing smod==pkg embedded-dot branch. * Cstage carries no sister bug — resolve_typename already routes * the bare-leaf TY_STRUCT name through scope_lookup_prefer per * c->cur_mod (cmd/wcc/check.c:60). * * Asserts the post-fix field-offset land inside the matching TEXT * sym on BOTH stages and that cs vs ws stay byte-identical on each * row. Row 1 sentinel-flips this commit's new same-module-first * walk (revert the structlookup change → row 1 fails on wwstage * + cs-vs-ws diff). Row 2 exercises the pre-existing embedded-dot * smod==pkg branch (unchanged here) — defensive coverage that * guards the second structlookup path against future regression; * does not sentinel-flip on this commit's change. */ #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; const char *textsym; /* TEXT sym containing the load */ const char *want_imm; /* the displacement that MUST appear */ const char *bad_imm; /* the displacement that MUST NOT appear */ }; /* Field layout (registerstruct: 8B alignment for >=8B, 4B for >=4). * Offsets chosen so neither digit-string is a substring of the * other (12 vs 32) — strstr-based needle matching would otherwise * spuriously hit "4(BX)," inside "24(BX),". * beta.S = { tag1, tag2, tag3, mark: i32 } → mark foff = 12, totsize = 16 * alpha.S = { p1, p2, p3, p4: i64, mark: i32 } * → mark foff = 32, totsize = 40 * * Source orderings pick which module's S sits at the head of * c.structs after collectstructs' head-prepend walk. The LAST `type * S = struct ...` in source order ends at the head — that's the * leaf-collision the same-module-first walk must beat. */ static const struct row rows[] = { { "bare_leaf_same_module", "package gamma;\n" "import alpha;\n" "import beta;\n" "export fn main() i32 = { return 0; };\n" "package beta;\n" "type S = struct { tag1: i32, tag2: i32, tag3: i32, mark: i32, };\n" "export fn readbetamark(s: *S) i32 = { return s.mark; };\n" "package alpha;\n" "type S = struct { p1: i64, p2: i64, p3: i64, p4: i64, mark: i32, };\n", "TEXT beta.readbetamark", "12(BX),", "32(BX)," }, /* `alpha.S` collapses into a single N_TNAME str at parse time * (lib/ww/parse/parse.ww joindotted), so structlookup is called * with "alpha.S" and falls through the new same-module-first * walk (no s.sname == "alpha.S") + head walk into the existing * embedded-dot branch (leaf="S", pkg="alpha", filter smod==pkg). * Pre/post-fix both pick alpha — row 2 sentinel-flips ONLY if * the smod==pkg filter regresses, pinning the second lookup * path independent of row 1's same-module-first walk. */ { "dot_qualified_explicit_module", "package gamma;\n" "import alpha;\n" "import beta;\n" "export fn main() i32 = { return 0; };\n" "package alpha;\n" "type S = struct { p1: i64, p2: i64, p3: i64, p4: i64, mark: i32, };\n" "export fn readalphamark(s: *alpha.S) i32 = { return s.mark; };\n" "package beta;\n" "type S = struct { tag1: i32, tag2: i32, tag3: i32, mark: i32, };\n", "TEXT alpha.readalphamark", "32(BX),", "12(BX)," }, }; static int slurp(const char *path, char *buf, size_t cap) { FILE *f = fopen(path, "rb"); if (!f) return -1; size_t n = fread(buf, 1, cap - 1, f); fclose(f); buf[n] = '\0'; return (int)n; } static int emit_s(const char *w6c, const struct row *r, int i, char *out_s, size_t cap) { char src[64], cmd[1024]; snprintf(src, sizeof src, "/tmp/sms_%d_%d.ww", getpid(), i); snprintf(out_s, cap, "/tmp/sms_%d_%d_%s.s", getpid(), i, w6c[strlen(w6c) - 1] == 'w' ? "ww" : "c"); FILE *f = fopen(src, "wb"); if (!f) return -1; fputs(r->src, f); fclose(f); snprintf(cmd, sizeof cmd, "%s -o %s %s 2>/dev/null", w6c, out_s, src); int rc = runwait(cmd); unlink(src); return rc; } /* Inside the named TEXT sym, before its first RET, the want_imm * MUST appear and the bad_imm MUST NOT. bad_imm flags pre-fix * head-walk picking the wrong-module S's field offset. */ static int check_imm(const char *spath, const struct row *r, const char *stage) { char buf[1 << 14]; if (slurp(spath, buf, sizeof buf) < 0) { fprintf(stderr, "row[%s][%s]: cannot read %s\n", r->label, stage, spath); return -1; } const char *fn = strstr(buf, r->textsym); if (!fn) { fprintf(stderr, "row[%s][%s]: no %s in %s\n", r->label, stage, r->textsym, spath); return -1; } const char *ret = strstr(fn, "\tRET"); if (!ret) { fprintf(stderr, "row[%s][%s]: no RET inside %s\n", r->label, stage, r->textsym); return -1; } const char *good = strstr(fn, r->want_imm); if (!good || good >= ret) { fprintf(stderr, "row[%s][%s]: want_imm %s missing inside %s\n", r->label, stage, r->want_imm, r->textsym); return -1; } const char *bad = strstr(fn, r->bad_imm); if (bad && bad < ret) { fprintf(stderr, "row[%s][%s]: bad_imm %s present inside %s — wrong-module S\n", r->label, stage, r->bad_imm, r->textsym); return -1; } return 0; } 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 w6c[640], w6c_ww[640]; snprintf(w6c, sizeof w6c, "%s/w6c", bin); snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin); int have_ww = (access(w6c_ww, X_OK) == 0); int n = (int)(sizeof rows / sizeof rows[0]); int total = 0, fail = 0; for (int i = 0; i < n; i++) { char cs_path[128], ws_path[128]; if (emit_s(w6c, &rows[i], i, cs_path, sizeof cs_path) != 0) { fprintf(stderr, "struct_modshadow[cstage][%s]: w6c failed\n", rows[i].label); fail++; total++; continue; } total++; if (check_imm(cs_path, &rows[i], "cstage") != 0) fail++; if (!have_ww) { unlink(cs_path); continue; } if (emit_s(w6c_ww, &rows[i], i, ws_path, sizeof ws_path) != 0) { fprintf(stderr, "struct_modshadow[wwstage][%s]: w6c_ww failed\n", rows[i].label); fail++; total++; unlink(cs_path); continue; } total++; if (check_imm(ws_path, &rows[i], "wwstage") != 0) fail++; total++; char cmd[512]; snprintf(cmd, sizeof cmd, "cmp -s %s %s", cs_path, ws_path); if (runwait(cmd) != 0) { fprintf(stderr, "struct_modshadow[%s]: cstage vs wwstage asm differs\n", rows[i].label); fail++; } unlink(cs_path); unlink(ws_path); } if (fail) { fprintf(stderr, "struct_modshadow: %d/%d fixtures failed\n", fail, total); return 1; } printf("struct_modshadow: %d/%d ok\n", total, total); return 0; }