compiler: support package test runtime aliases

selfhost/cmd/w6c/main.ww

@@ -66,6 +66,7 @@ export fn main(argc: i32, argv: **u8) i32 = {
 	let src: *u8 = nil;
 	let out: *u8 = nil;
 	let wwiout: *u8 = nil;		// -I <out.wwi>: M2 export-data producer
+	let testsupport: *u8 = nil;
 	let testmode: i32 = 0i32;	// #15: `-T` test-mode
 	let sepmode: i32 = 0i32;	// -c: #22 M3 separate-compile / primary-
 					// only codegen (emit imported==0 decls
@@ -92,6 +93,14 @@ export fn main(argc: i32, argv: **u8) i32 = {
 			wwiout = argv[i];
 		} else { if (cstreq(a, "-T")) {
 			testmode = 1i32;
+		} else { if (cstreq(a, "--test-support-module")) {
+			i += 1;
+			if (i >= argc) {
+				let m: str = "w6c: --test-support-module requires arg\n";
+				os.write(2, m.ptr, m.len: u64);
+				return 2;
+			};
+			testsupport = argv[i];
 		} else { if (cstreq(a, "-c")) {
 			sepmode = 1i32;
 		} else { if (a[0u64] == 45u8) {
@@ -105,7 +114,7 @@ export fn main(argc: i32, argv: **u8) i32 = {
 				return 2;
 			};
 			src = a;
-		}; }; }; }; };
+		}; }; }; }; }; };
 		i += 1;
 	};
 
@@ -114,6 +123,13 @@ export fn main(argc: i32, argv: **u8) i32 = {
 		os.write(2, m.ptr, m.len: u64);
 		return 2;
 	};
+	if (testsupport != nil && (sepmode == 0
+		|| (!cstreq(testsupport, "test")
+			&& !cstreq(testsupport, "__wwtest")))) {
+		let m: str = "w6c: invalid --test-support-module\n";
+		os.write(2, m.ptr, m.len: u64);
+		return 2;
+	};
 
 	let buf: *u8;
 	let blen: u64;
@@ -155,6 +171,7 @@ export fn main(argc: i32, argv: **u8) i32 = {
 
 	let ps: parser;
 	parserinit(&ps, &l);
+	if (testsupport != nil) { ps.testmodule = pathstr(testsupport); };
 	let f: *node = parsefile(&ps);
 	// Gate cgen on parse-stage errors. Mirrors cmd/w6c/main.c's
 	// `if (l.errs || p.errs) return 1;` — broken AST otherwise reaches
@@ -172,6 +189,7 @@ export fn main(argc: i32, argv: **u8) i32 = {
 	let ck: checker;
 	checkinit(&ck, &tc);
 	ck.istest = testmode;
+	if (testsupport != nil) { ck.testmodule = pathstr(testsupport); };
 	ck.sepmode = sepmode;
 	checkfile(&ck, f);
 	if (ck.errs > 0) { return 1; };