PR middle-end/93646 - confusing -Wstringop-truncation on strncat where -Wstringop-overflow is expected
gcc/ChangeLog:
PR middle-end/93646
* tree-ssa-strlen.c (handle_builtin_stxncpy): Rename...
(handle_builtin_stxncpy_strncat): ...to this. Change first argument.
Issue only -Wstringop-overflow strncat, never -Wstringop-truncation.
(strlen_check_and_optimize_call): Adjust callee name.
gcc/testsuite/ChangeLog:
PR middle-end/93646
* gcc.dg/Wstringop-overflow-31.c: New test.
new file mode 100644
@@ -0,0 +1,40 @@
+/* PR middle-end/93646 - confusing -Wstringop-truncation on strncat where
+ -Wstringop-overflow is expected
+ { dg-do compile }
+ { dg-options "-O2 -Wall" } */
+
+extern __SIZE_TYPE__ strlen (const char*);
+extern char* strncat (char*, const char*, __SIZE_TYPE__);
+
+
+char a[4];
+
+
+void f0 (char *d, const char *s)
+{
+ strncat (d, s, strlen (s)); // { dg-warning "specified bound depends on the length of the source argument" }
+ /* { dg-message "function 'f0'.*inlined from 'f1'" "inlining stack" { target *-*-* } 0 } */
+
+ // Prevent f0 from being replaced by g0.
+ *d = 'f';
+}
+
+void f1 (const char *s)
+{
+ f0 (a, s);
+}
+
+
+static void g0 (char *d, const char *s)
+{
+ strncat (d, s, strlen (s)); // { dg-warning "specified bound 3 equals source length" }
+ /* { dg-message "function 'g0'.*inlined from 'g1'" "inlining stack" { target *-*-* } 0 } */
+
+ // Prevent g0 from being replaced by f0.
+ *d = 'g';
+}
+
+void g1 (void)
+{
+ g0 (a, "123");
+}
@@ -192,7 +192,7 @@ struct laststmt_struct
} laststmt;
static int get_stridx_plus_constant (strinfo *, unsigned HOST_WIDE_INT, tree);
-static void handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *);
+static void handle_builtin_stxncpy_strncat (bool, gimple_stmt_iterator *);
/* Sets MINMAX to either the constant value or the range VAL is in
and returns either the constant value or VAL on success or null
@@ -2876,10 +2876,10 @@ handle_builtin_strcpy (enum built_in_function bcode, gimple_stmt_iterator *gsi,
and if so, issue an appropriate warning. */
static void
-handle_builtin_strncat (built_in_function bcode, gimple_stmt_iterator *gsi)
+handle_builtin_strncat (built_in_function, gimple_stmt_iterator *gsi)
{
/* Same as stxncpy(). */
- handle_builtin_stxncpy (bcode, gsi);
+ handle_builtin_stxncpy_strncat (true, gsi);
}
/* Return true if LEN depends on a call to strlen(SRC) in an interesting
@@ -2974,8 +2974,8 @@ is_strlen_related_p (tree src, tree len)
return false;
}
-/* Called by handle_builtin_stxncpy and by gimple_fold_builtin_strncpy
- in gimple-fold.c.
+/* Called by handle_builtin_stxncpy_strncat and by
+ gimple_fold_builtin_strncpy in gimple-fold.c.
Check to see if the specified bound is a) equal to the size of
the destination DST and if so, b) if it's immediately followed by
DST[CNT - 1] = '\0'. If a) holds and b) does not, warn. Otherwise,
@@ -3283,13 +3283,14 @@ maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt)
return false;
}
-/* Check the arguments to the built-in forms of stpncpy and strncpy for
- out-of-bounds offsets or overlapping access, and to see if the size
- is derived from calling strlen() on the source argument, and if so,
- issue the appropriate warning. */
+/* Check the arguments to the built-in forms of stpncpy, strncpy, and
+ strncat, for out-of-bounds offsets or overlapping access, and to see
+ if the size is derived from calling strlen() on the source argument,
+ and if so, issue the appropriate warning.
+ APPEND_P is true for strncat. */
static void
-handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi)
+handle_builtin_stxncpy_strncat (bool append_p, gimple_stmt_iterator *gsi)
{
if (!strlen_to_stridx)
return;
@@ -3385,7 +3386,8 @@ handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi)
whether its value is known. Otherwise, issue the more generic
-Wstringop-overflow which triggers for LEN arguments that in
any meaningful way depend on strlen(SRC). */
- if (sisrc == silen
+ if (!append_p
+ && sisrc == silen
&& is_strlen_related_p (src, len)
&& warning_at (callloc, OPT_Wstringop_truncation,
"%G%qD output truncated before terminating nul "
@@ -5352,7 +5354,7 @@ strlen_check_and_optimize_call (gimple_stmt_iterator *gsi, bool *zero_write,
case BUILT_IN_STPNCPY_CHK:
case BUILT_IN_STRNCPY:
case BUILT_IN_STRNCPY_CHK:
- handle_builtin_stxncpy (DECL_FUNCTION_CODE (callee), gsi);
+ handle_builtin_stxncpy_strncat (false, gsi);
break;
case BUILT_IN_MEMCPY: