improve self tests, include zero sign test (tcc)

src/duk_selftest.c

@@ -8,26 +8,43 @@
 #if defined(DUK_USE_SELF_TESTS)
 
 /*
- *  Self test for union aliasing, see misc/clang_aliasing.c.
+ *  Test union for double-related self tests
  */
 
 typedef union {
 	double d;
 	unsigned char c[8];
-} duk_alias_test_union;
+} duk_test_union;
 
-#define DUK_UNION_CMP()  do { \
-		if (DUK_MEMCMP((void *) &a, (void *) &b, sizeof(a)) != 0) { \
-			DUK_PANIC(DUK_ERR_INTERNAL_ERROR, "union aliasing self test failed: compare failed"); \
+#define DUK_UNION_CMP_TRUE(a,b)  do { \
+		if (DUK_MEMCMP((void *) (a), (void *) (b), sizeof(duk_test_union)) != 0) { \
+			DUK_PANIC(DUK_ERR_INTERNAL_ERROR, "self test failed: double union compares false (expected true)"); \
 		} \
 	} while (0)
 
-static void duk_selftest_tval_aliasing(void) {
-	duk_alias_test_union a, b;
+#define DUK_UNION_CMP_FALSE(a,b)  do { \
+		if (DUK_MEMCMP((void *) (a), (void *) (b), sizeof(duk_test_union)) == 0) { \
+			DUK_PANIC(DUK_ERR_INTERNAL_ERROR, "self test failed: double union compares true (expected false)"); \
+		} \
+	} while (0)
+
+
+/*
+ *  Self test for basic double / byte union memory layout
 
-	if (sizeof(duk_alias_test_union) != 8) {
-		DUK_PANIC(DUK_ERR_INTERNAL_ERROR, "union aliasing self test failed: invalid union size");
+ */
+static void duk_selftest_union_size(void) {
+	if (sizeof(duk_test_union) != 8) {
+		DUK_PANIC(DUK_ERR_INTERNAL_ERROR, "self test failed: invalid union size");
 	}
+}
+
+/*
+ *  Self test for union aliasing, see misc/clang_aliasing.c.
+ */
+
+static void duk_selftest_double_aliasing(void) {
+	duk_test_union a, b;
 
 	/* Test signaling NaN and alias assignment in all
 	 * endianness combinations.
@@ -37,28 +54,39 @@ static void duk_selftest_tval_aliasing(void) {
 	a.c[0] = 0x11; a.c[1] = 0x22; a.c[2] = 0x33; a.c[3] = 0x44;
 	a.c[4] = 0x00; a.c[5] = 0x00; a.c[6] = 0xf1; a.c[7] = 0xff;
 	b = a;
-	DUK_UNION_CMP();
+	DUK_UNION_CMP_TRUE(&a, &b);
 
 	/* big endian */
 	a.c[0] = 0xff; a.c[1] = 0xf1; a.c[2] = 0x00; a.c[3] = 0x00;
 	a.c[4] = 0x44; a.c[5] = 0x33; a.c[6] = 0x22; a.c[7] = 0x11;
 	b = a;
-	DUK_UNION_CMP();
+	DUK_UNION_CMP_TRUE(&a, &b);
 
 	/* middle endian */
 	a.c[0] = 0x00; a.c[1] = 0x00; a.c[2] = 0xf1; a.c[3] = 0xff;
 	a.c[4] = 0x11; a.c[5] = 0x22; a.c[6] = 0x33; a.c[7] = 0x44;
 	b = a;
-	DUK_UNION_CMP();
+	DUK_UNION_CMP_TRUE(&a, &b);
+}
+
+static void duk_selftest_double_zero_sign(void) {
+	volatile duk_test_union a, b;
+
+	a.d = 0.0;
+	b.d = -a.d;
+	DUK_UNION_CMP_FALSE(&a, &b);
 }
-#undef DUK_UNION_CMP
 
 /*
  *  Self test main
  */
 
 void duk_selftest_run_tests(void) {
-	duk_selftest_tval_aliasing();
+	duk_selftest_union_size();
+	duk_selftest_double_aliasing();
+	duk_selftest_double_zero_sign();
 }
 
+#undef DUK_UNION_CMP
+
 #endif  /* DUK_USE_SELF_TESTS */