* common.opt (Wstring-literal-comparison): New command line option.
* c-opts.c (c_common_handle_option): Set it with -Wall.
* c-typeck.c (parser_build_binary_op): Issue warning if either
operand of a comparison operator is a string literal, except for
testing equality or inequality against NULL.
* doc/invoke.texi: Document new -Wstring-literal-comparison option.
* gcc.dg/Wstring-literal-comparison-1.c: New test case.
* gcc.dg/Wstring-literal-comparison-2.c: Likewise.
* gcc.dg/Wstring-literal-comparison-3.c: Likewise.
* gcc.dg/Wstring-literal-comparison-4.c: Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@108018
138bc75d-0d04-0410-961f-
82ee72b054a4
+2005-12-04 Roger Sayle <roger@eyesopen.com>
+
+ PR c/7776
+ * common.opt (Wstring-literal-comparison): New command line option.
+ * c-opts.c (c_common_handle_option): Set it with -Wall.
+ * c-typeck.c (parser_build_binary_op): Issue warning if either
+ operand of a comparison operator is a string literal, except for
+ testing equality or inequality against NULL.
+
+ * doc/invoke.texi: Document new -Wstring-literal-comparison option.
+
2005-12-03 Joseph S. Myers <joseph@codesourcery.com>
* c-common.c (c_sizeof_or_alignof_type): Use fold_convert instead
warn_sign_compare = value;
warn_switch = value;
warn_strict_aliasing = value;
+ warn_string_literal_comparison = value;
/* Only warn about unknown pragmas that are not in system
headers. */
}
+ /* Warn about comparisons against string literals, with the exception
+ of testing for equality or inequality of a string literal with NULL. */
+ if (code == EQ_EXPR || code == NE_EXPR)
+ {
+ if ((code1 == STRING_CST && !integer_zerop (arg2.value))
+ || (code2 == STRING_CST && !integer_zerop (arg1.value)))
+ warning (OPT_Wstring_literal_comparison,
+ "comparison with string literal");
+ }
+ else if (TREE_CODE_CLASS (code) == tcc_comparison
+ && (code1 == STRING_CST || code2 == STRING_CST))
+ warning (OPT_Wstring_literal_comparison,
+ "comparison with string literal");
+
unsigned_conversion_warning (result.value, arg1.value);
unsigned_conversion_warning (result.value, arg2.value);
overflow_warning (result.value);
Common Joined UInteger
Warn about code which might break strict aliasing rules
+Wstring-literal-comparison
+Common Var(warn_string_literal_comparison)
+Warn about comparisons to constant string literals
+
Wswitch
Common Var(warn_switch)
Warn about enumerated switches, with no default, missing a case
+2005-12-04 Roger Sayle <roger@eyesopen.com>
+
+ PR c/7776
+ * gcc.dg/Wstring-literal-comparison-1.c: New test case.
+ * gcc.dg/Wstring-literal-comparison-2.c: Likewise.
+ * gcc.dg/Wstring-literal-comparison-3.c: Likewise.
+ * gcc.dg/Wstring-literal-comparison-4.c: Likewise.
+
2005-12-03 Joseph S. Myers <joseph@codesourcery.com>
* gcc.dg/cast-pretty-print-1.c: New test.
--- /dev/null
+/* PR c/7776 */
+/* { dg-do compile } */
+/* { dg-options "-Wstring-literal-comparison" } */
+
+int test1(char *ptr)
+{
+ return ptr == "foo"; /* { dg-warning "comparison with string" } */
+}
+
+int test2()
+{
+ return "foo" != (const char*)0;
+}
+
+int test3()
+{
+ return "foo" == (const char*)0;
+}
+
+int test4()
+{
+ return (const char*)0 != "foo";
+}
+
+int test5()
+{
+ return (const char*)0 == "foo";
+}
+
--- /dev/null
+/* PR c/7776 */
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+
+int test1(char *ptr)
+{
+ return ptr == "foo"; /* { dg-warning "comparison with string" } */
+}
+
+int test2()
+{
+ return "foo" != (const char*)0;
+}
+
+int test3()
+{
+ return "foo" == (const char*)0;
+}
+
+int test4()
+{
+ return (const char*)0 != "foo";
+}
+
+int test5()
+{
+ return (const char*)0 == "foo";
+}
+
--- /dev/null
+/* PR c/7776 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int test1(char *ptr)
+{
+ return ptr == "foo";
+}
+
+int test2()
+{
+ return "foo" != (const char*)0;
+}
+
+int test3()
+{
+ return "foo" == (const char*)0;
+}
+
+int test4()
+{
+ return (const char*)0 != "foo";
+}
+
+int test5()
+{
+ return (const char*)0 == "foo";
+}
+
--- /dev/null
+/* PR c/7776 */
+/* { dg-do compile } */
+/* { dg-options "-Wall -Wno-string-literal-comparison" } */
+
+int test1(char *ptr)
+{
+ return ptr == "foo";
+}
+
+int test2()
+{
+ return "foo" != (const char*)0;
+}
+
+int test3()
+{
+ return "foo" == (const char*)0;
+}
+
+int test4()
+{
+ return (const char*)0 != "foo";
+}
+
+int test5()
+{
+ return (const char*)0 == "foo";
+}
+