Module Name: src
Committed By: rillig
Date: Fri May 14 21:14:55 UTC 2021
Modified Files:
src/distrib/sets/lists/tests: mi
src/tests/usr.bin/xlint/lint1: Makefile t_integration.sh
Added Files:
src/tests/usr.bin/xlint/lint1: expr_range.c
Log Message:
tests/lint: test bitwise mismatch in switch statement
To generate a diff of this commit:
cvs rdiff -u -r1.1049 -r1.1050 src/distrib/sets/lists/tests/mi
cvs rdiff -u -r1.55 -r1.56 src/tests/usr.bin/xlint/lint1/Makefile
cvs rdiff -u -r0 -r1.1 src/tests/usr.bin/xlint/lint1/expr_range.c
cvs rdiff -u -r1.48 -r1.49 src/tests/usr.bin/xlint/lint1/t_integration.sh
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/distrib/sets/lists/tests/mi
diff -u src/distrib/sets/lists/tests/mi:1.1049 src/distrib/sets/lists/tests/mi:1.1050
--- src/distrib/sets/lists/tests/mi:1.1049 Sun May 2 21:22:09 2021
+++ src/distrib/sets/lists/tests/mi Fri May 14 21:14:55 2021
@@ -1,4 +1,4 @@
-# $NetBSD: mi,v 1.1049 2021/05/02 21:22:09 rillig Exp $
+# $NetBSD: mi,v 1.1050 2021/05/14 21:14:55 rillig Exp $
#
# Note: don't delete entries from here - mark them as "obsolete" instead.
#
@@ -6189,6 +6189,7 @@
./usr/tests/usr.bin/xlint/lint1/emit.c tests-usr.bin-tests compattestfile,atf
./usr/tests/usr.bin/xlint/lint1/emit.exp tests-usr.bin-tests compattestfile,atf
./usr/tests/usr.bin/xlint/lint1/emit.ln tests-usr.bin-tests compattestfile,atf
+./usr/tests/usr.bin/xlint/lint1/expr_range.c tests-usr.bin-tests compattestfile,atf
./usr/tests/usr.bin/xlint/lint1/feat_stacktrace.c tests-usr.bin-tests compattestfile,atf
./usr/tests/usr.bin/xlint/lint1/feat_stacktrace.exp tests-usr.bin-tests compattestfile,atf
./usr/tests/usr.bin/xlint/lint1/gcc_attribute.c tests-usr.bin-tests compattestfile,atf
Index: src/tests/usr.bin/xlint/lint1/Makefile
diff -u src/tests/usr.bin/xlint/lint1/Makefile:1.55 src/tests/usr.bin/xlint/lint1/Makefile:1.56
--- src/tests/usr.bin/xlint/lint1/Makefile:1.55 Sun May 2 21:22:09 2021
+++ src/tests/usr.bin/xlint/lint1/Makefile Fri May 14 21:14:55 2021
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.55 2021/05/02 21:22:09 rillig Exp $
+# $NetBSD: Makefile,v 1.56 2021/05/14 21:14:55 rillig Exp $
NOMAN= # defined
MAX_MESSAGE= 343 # see lint1/err.c
@@ -103,6 +103,7 @@ FILES+= d_zero_sized_arrays.c
FILES+= emit.c
FILES+= emit.exp
FILES+= emit.ln
+FILES+= expr_range.c
FILES+= feat_stacktrace.c
FILES+= feat_stacktrace.exp
FILES+= gcc_attribute.c
Index: src/tests/usr.bin/xlint/lint1/t_integration.sh
diff -u src/tests/usr.bin/xlint/lint1/t_integration.sh:1.48 src/tests/usr.bin/xlint/lint1/t_integration.sh:1.49
--- src/tests/usr.bin/xlint/lint1/t_integration.sh:1.48 Mon May 3 03:50:43 2021
+++ src/tests/usr.bin/xlint/lint1/t_integration.sh Fri May 14 21:14:55 2021
@@ -1,4 +1,4 @@
-# $NetBSD: t_integration.sh,v 1.48 2021/05/03 03:50:43 rillig Exp $
+# $NetBSD: t_integration.sh,v 1.49 2021/05/14 21:14:55 rillig Exp $
#
# Copyright (c) 2008, 2010 The NetBSD Foundation, Inc.
# All rights reserved.
@@ -175,6 +175,7 @@ test_case d_incorrect_array_size
test_case d_long_double_int
test_case emit
+test_case expr_range
test_case gcc_attribute
test_case gcc_attribute_aligned
Added files:
Index: src/tests/usr.bin/xlint/lint1/expr_range.c
diff -u /dev/null src/tests/usr.bin/xlint/lint1/expr_range.c:1.1
--- /dev/null Fri May 14 21:14:56 2021
+++ src/tests/usr.bin/xlint/lint1/expr_range.c Fri May 14 21:14:55 2021
@@ -0,0 +1,37 @@
+/* $NetBSD: expr_range.c,v 1.1 2021/05/14 21:14:55 rillig Exp $ */
+# 3 "expr_range.c"
+
+/*
+ * Test whether lint can detect switch branches that are impossible to reach.
+ * As of 2021-05-14, it cannot. To do this, it would need to keep track of
+ * the possible values of each variable or expression. To do this reliably,
+ * it would also need accurate control flow analysis, which as of 2021-05-14
+ * works only for functions without 'goto'.
+ *
+ * GCC 10 does not complain the unreachable branch. It knows that the branch
+ * is unreachable though since it doesn't generate any code for it. GCC once
+ * had the option -Wunreachable-code, but that option was made a no-op in
+ * 2011.
+ *
+ * Clang 10 does not complain about this either, and just like GCC it doesn't
+ * generate any code for this branch. The code for tracking an expression's
+ * possible values may be related to RangeConstraintManager, just guessing.
+ *
+ * There should be at least one static analysis tool that warns about this.
+ */
+
+/* lint1-extra-flags: -chap */
+
+void
+example(unsigned x)
+{
+ switch (x & 6) {
+ case 1:
+ /* This branch is unreachable. */
+ printf("one\n");
+ break;
+ case 2:
+ printf("two\n");
+ break;
+ }
+}
