wcc/ww: global-str default-hi slice arg loads its len word

Slicing a module-global str with default hi emitted nothing for the
bound; load the len word from g(SB)+8 (mirror the cstage twin).
Review item #47; dual-stage rows red-proven.

Makefile

@@ -256,6 +256,7 @@ TESTS	= $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
 	  $(BIN)/test_fnptrcollide_run \
 	  $(BIN)/test_tagnorm_run \
 	  $(BIN)/test_globslicefield_run \
+	  $(BIN)/test_globstrslice_run \
 	  $(BIN)/test_arr_ptr_global \
 	  $(BIN)/test_def_arr_infer_len \
 	  $(BIN)/test_def_arr_len \
@@ -723,6 +724,17 @@ $(BIN)/test_globslicefield_run: test/wcc/989_globslicefield_run.c \
 		$(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<
 
+# 989_globstrslice_run (F8-c2, #47): a module-global str sliced with a
+# default high bound and passed as a call arg (`take(g[1:])`) must load its
+# length word for the hi. Builds+runs on BOTH driver twins (rule-10);
+# align-UP — see the test header.
+$(BIN)/test_globstrslice_run: test/wcc/989_globstrslice_run.c \
+		$(BIN)/ww $(BIN)/ww_ww \
+		$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
+		$(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
+		$(LIB)/libwwrt.a | $(BIN)
+	$(CC) $(CFLAGS) -o $@ $<
+
 $(BIN)/test_let_global: test/wcc/630_let_global.c $(BIN)/ww $(BIN)/w6c \
 		$(BIN)/w6a $(BIN)/w6l $(LIB)/libwwrt.a | $(BIN)
 	$(CC) $(CFLAGS) -o $@ $<

selfhost/cmd/w6c/main.combined.ww

@@ -18040,7 +18040,14 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 				emitsymname(c, globalname);
 				emitline("(SB), CX\n");
 				emitline("\tMOVQ\t8(CX), AX\n");
-			};};
+			} else { if (globaltn.kind == nkind.N_TNAME) {
+				if (streq(globaltn.str, "str")) {
+					emitline("\tLEAQ\t");
+					emitsymname(c, globalname);
+					emitline("(SB), CX\n");
+					emitline("\tMOVQ\t8(CX), AX\n");
+				};
+			};};};
 			// #60: alias-NAMED global base default-hi — chased
 			// kind; runtime-unreachable until #77/#78 global DATA.
 			if (bu60 != nil) {

selfhost/cmd/wcc/cgenutil.ww

@@ -620,7 +620,14 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 				emitsymname(c, globalname);
 				emitline("(SB), CX\n");
 				emitline("\tMOVQ\t8(CX), AX\n");
-			};};
+			} else { if (globaltn.kind == nkind.N_TNAME) {
+				if (streq(globaltn.str, "str")) {
+					emitline("\tLEAQ\t");
+					emitsymname(c, globalname);
+					emitline("(SB), CX\n");
+					emitline("\tMOVQ\t8(CX), AX\n");
+				};
+			};};};
 			// #60: alias-NAMED global base default-hi — chased
 			// kind; runtime-unreachable until #77/#78 global DATA.
 			if (bu60 != nil) {

selfhost/cmd/wwdump/main.combined.ww

@@ -18040,7 +18040,14 @@ fn pushargsrev(c: *cgen, arg: *node, param: *node, memphase: bool) i32 = {
 				emitsymname(c, globalname);
 				emitline("(SB), CX\n");
 				emitline("\tMOVQ\t8(CX), AX\n");
-			};};
+			} else { if (globaltn.kind == nkind.N_TNAME) {
+				if (streq(globaltn.str, "str")) {
+					emitline("\tLEAQ\t");
+					emitsymname(c, globalname);
+					emitline("(SB), CX\n");
+					emitline("\tMOVQ\t8(CX), AX\n");
+				};
+			};};};
 			// #60: alias-NAMED global base default-hi — chased
 			// kind; runtime-unreachable until #77/#78 global DATA.
 			if (bu60 != nil) {

test/wcc/989_globstrslice_run.c

@@ -0,0 +1,166 @@
+/*
+ * 989_globstrslice_run — F8-c2 (report-item #47): a module-GLOBAL str
+ * sliced with a DEFAULT high bound and passed as a call arg (`take(g[1:])`)
+ * must load its length word for the hi — both stages, byte-identical.
+ *
+ * THE BUG (cat-A silent miscompile, align-UP): in cgenutil.ww the N_SLICE
+ * call-arg pusharg builds {cap,len,ptr} on the stack. For a DEFAULT hi
+ * (`g[lo:]`) it picks the base length per base kind. The global-base branch
+ * handled N_TARRAY and N_TSLICE but had NO arm for a global str (N_TNAME
+ * "str"), so AX kept the base pointer (loaded for the base push) and got
+ * PUSHQ'd as the hi → len = ptr - lo, garbage. The LOCAL-str arm and the
+ * alias-NAMED (bu60) arm already loaded the +8 length word; only the plain
+ * global-str arm was missing. cstage pushargs reads the base type via
+ * type_chase_named uniformly (cmd/w6c/cgen.c N_SLICE), so it loaded the len
+ * and ran correct — the cat-A divergence (990-997 never slice a global str
+ * arg with a default hi, so they stayed green).
+ *
+ * THE FIX: the global default-hi branch grows an N_TNAME "str" arm emitting
+ * the same `LEAQ g(SB),CX; MOVQ 8(CX),AX` as the global N_TSLICE arm (str IS
+ * []u8 — the len word sits at +8). align ww UP; the .s is byte-identical.
+ *
+ * Rows (build+run on cstage `ww` and wwstage `ww_ww`; rule-10 — agree+hit):
+ *   row             | shape                         | want
+ *   ----------------+-------------------------------+-----
+ *   gstr_defhi      | slen(g[1:])  g="hello"        | 4 [#47 bug — len ptr-lo]
+ *   gstr_defhi_full | slen(g[0:])  lo=0 default hi  | 5 [#47 bug]
+ *   gstr_defhi_ptr  | sfirst(g[1:])  s[0]=='e'      | 101 [ptr word still ok]
+ *   gstr_explicit   | slen(g[1:3])  hi explicit     | 2 (control: hi!=nil path
+ *                   |                                | must not regress)
+ */
+#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_exit;
+};
+
+#define PRELUDE \
+	"package main;\n" \
+	"let g: str = \"hello\";\n" \
+	"fn slen(s: str) int = { return len(s): int; };\n" \
+	"fn sfirst(s: str) int = { return s[0]: int; };\n"
+
+static const struct row rows[] = {
+	{ "gstr_defhi",
+	  PRELUDE
+	  "export fn main() int = { return slen(g[1:]); };\n",
+	  4 },
+
+	{ "gstr_defhi_full",
+	  PRELUDE
+	  "export fn main() int = { return slen(g[0:]); };\n",
+	  5 },
+
+	{ "gstr_defhi_ptr",
+	  PRELUDE
+	  "export fn main() int = { return sfirst(g[1:]); };\n",
+	  101 },
+
+	{ "gstr_explicit",
+	  PRELUDE
+	  "export fn main() int = { return slen(g[1:3]); };\n",
+	  2 },
+};
+
+/* run_build — build+run `src` via `driver`; returns the binary's exit
+ * code, or -1 on a build failure. */
+static int
+run_build(const char *driver, const struct row *r, int i)
+{
+	char src[64], tmpdir[64], cmd[1024];
+	snprintf(src, sizeof src, "/tmp/gss_%d_%d.ww", getpid(), i);
+	snprintf(tmpdir, sizeof tmpdir, "/tmp/gss_%d_d_%d", getpid(), i);
+
+	FILE *f = fopen(src, "wb");
+	if (!f) return -2;
+	fputs(r->src, f);
+	fclose(f);
+
+	mkdir(tmpdir, 0755);
+	snprintf(cmd, sizeof cmd, "cd %s && %s build %s 2>/dev/null",
+	    tmpdir, driver, src);
+	int brc = runwait(cmd);
+
+	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 = -1;
+	if (brc == 0) got = runwait(outbin);
+
+	unlink(src); unlink(outbin); rmdir(tmpdir);
+	return brc == 0 ? got : -1;
+}
+
+int
+main(void)
+{
+	const char *bin = getenv("BIN");
+	if (!bin) bin = "out/bin";
+	char absbin[1024];
+	if (bin[0] != '/') {
+		char cwd[1024];
+		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
+		bin = absbin;
+	}
+
+	char cdrv[1024], wdrv[1024];
+	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
+	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
+
+	struct { const char *name; const char *drv; int gated; }
+	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 && access(drivers[d].drv, X_OK) != 0) {
+			fprintf(stderr, "globstrslice_run: skip %s (no %s)\n",
+			    drivers[d].name, drivers[d].drv);
+			continue;
+		}
+		for (int i = 0; i < n; i++) {
+			total++;
+			int got = run_build(drivers[d].drv, &rows[i], i);
+			if (got != rows[i].want_exit) {
+				fprintf(stderr, "globstrslice_run[%s][%s]: exit=%d "
+				    "want=%d\n", drivers[d].name, rows[i].label,
+				    got, rows[i].want_exit);
+				fail++;
+			}
+		}
+	}
+
+	if (fail) {
+		fprintf(stderr, "globstrslice_run: %d/%d fixtures failed\n",
+		    fail, total);
+		return 1;
+	}
+	printf("globstrslice_run: %d/%d ok\n", total, total);
+	return 0;
+}