Module Name: src
Committed By: rillig
Date: Sun Jan 31 13:11:08 UTC 2021
Modified Files:
src/tests/usr.bin/xlint/lint1: msg_166.c msg_166.exp
Log Message:
lint: add test for lossy assignments to bit-fields (164, 166)
To generate a diff of this commit:
cvs rdiff -u -r1.1 -r1.2 src/tests/usr.bin/xlint/lint1/msg_166.c \
src/tests/usr.bin/xlint/lint1/msg_166.exp
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/usr.bin/xlint/lint1/msg_166.c
diff -u src/tests/usr.bin/xlint/lint1/msg_166.c:1.1 src/tests/usr.bin/xlint/lint1/msg_166.c:1.2
--- src/tests/usr.bin/xlint/lint1/msg_166.c:1.1 Sat Jan 2 10:22:43 2021
+++ src/tests/usr.bin/xlint/lint1/msg_166.c Sun Jan 31 13:11:08 2021
@@ -1,7 +1,59 @@
-/* $NetBSD: msg_166.c,v 1.1 2021/01/02 10:22:43 rillig Exp $ */
+/* $NetBSD: msg_166.c,v 1.2 2021/01/31 13:11:08 rillig Exp $ */
# 3 "msg_166.c"
// Test for message: precision lost in bit-field assignment [166]
-TODO: "Add example code that triggers the above message."
-TODO: "Add example code that almost triggers the above message."
+/* lint1-extra-flags: -hp */
+
+struct bit_set {
+
+ /*
+ * C99 6.7.2p5 and 6.7.2.1p9 footnote 104 say that for bit-fields of
+ * underlying type 'int', "it is implementation-defined whether the
+ * specifier 'int' designates the same type as 'signed int' or the
+ * same type as 'unsigned int'".
+ *
+ * https://gcc.gnu.org/onlinedocs/gcc/Structures-unions-enumerations
+ * -and-bit-fields-implementation.html says: "By default it is treated
+ * as 'signed int' but this may be changed by the
+ * '-funsigned-bitfields' option".
+ *
+ * Clang doesn't document implementation-defined behavior, see
+ * https://bugs.llvm.org/show_bug.cgi?id=11272.
+ */
+
+ int minus_1_to_0: 1; /* expect: 34 */
+ int minus_8_to_7: 4; /* expect: 34 */
+ unsigned zero_to_1: 1;
+ unsigned zero_to_15: 4;
+};
+
+void example(void) {
+ struct bit_set bits;
+
+ /* Clang doesn't warn about the 1. */
+ bits.minus_1_to_0 = -2; /* expect: 166 */
+ bits.minus_1_to_0 = -1;
+ bits.minus_1_to_0 = 0;
+ bits.minus_1_to_0 = 1; /* expect: 166 */
+ bits.minus_1_to_0 = 2; /* expect: 166 */
+
+ bits.minus_8_to_7 = -9; /* expect: 166 */
+ bits.minus_8_to_7 = -8;
+ bits.minus_8_to_7 = 7;
+ bits.minus_8_to_7 = 8; /* expect: 166 */
+
+ /* Clang doesn't warn about the -1. */
+ bits.zero_to_1 = -2; /* expect: 164 */
+ bits.zero_to_1 = -1; /* expect: 164 */
+ bits.zero_to_1 = 0;
+ bits.zero_to_1 = 1;
+ bits.zero_to_1 = 2; /* expect: 166 */
+
+ /* Clang doesn't warn about the -8. */
+ bits.zero_to_15 = -9; /* expect: 164 */
+ bits.zero_to_15 = -8; /* expect: 164 */
+ bits.zero_to_15 = 0;
+ bits.zero_to_15 = 15;
+ bits.zero_to_15 = 16; /* expect: 166 */
+}
Index: src/tests/usr.bin/xlint/lint1/msg_166.exp
diff -u src/tests/usr.bin/xlint/lint1/msg_166.exp:1.1 src/tests/usr.bin/xlint/lint1/msg_166.exp:1.2
--- src/tests/usr.bin/xlint/lint1/msg_166.exp:1.1 Sat Jan 2 10:22:43 2021
+++ src/tests/usr.bin/xlint/lint1/msg_166.exp Sun Jan 31 13:11:08 2021
@@ -1 +1,13 @@
-msg_166.c(6): syntax error ':' [249]
+msg_166.c(25): warning: nonportable bit-field type [34]
+msg_166.c(26): warning: nonportable bit-field type [34]
+msg_166.c(35): warning: precision lost in bit-field assignment [166]
+msg_166.c(38): warning: precision lost in bit-field assignment [166]
+msg_166.c(39): warning: precision lost in bit-field assignment [166]
+msg_166.c(41): warning: precision lost in bit-field assignment [166]
+msg_166.c(44): warning: precision lost in bit-field assignment [166]
+msg_166.c(47): warning: assignment of negative constant to unsigned type [164]
+msg_166.c(48): warning: assignment of negative constant to unsigned type [164]
+msg_166.c(51): warning: precision lost in bit-field assignment [166]
+msg_166.c(54): warning: assignment of negative constant to unsigned type [164]
+msg_166.c(55): warning: assignment of negative constant to unsigned type [164]
+msg_166.c(58): warning: precision lost in bit-field assignment [166]
