PR tree-optimization/82945 - add warning for passing non-strings to functions that expect string arguments

gcc/ChangeLog:

	PR tree-optimization/82945
	* builtins.c (expand_builtin_strlen): Call maybe_warn_nonstring_arg.
	* calls.h (maybe_warn_nonstring_arg): Declare new function.
	* calls.c (get_attr_nonstring_decl, maybe_warn_nonstring_arg): New
	functions.
	(initialize_argument_information): Call maybe_warn_nonstring_arg.
	* calls.h (get_attr_nonstring_decl): Declare new function.
	* doc/extend.texi (attribute nonstring): Update.
	* gimple-fold.c (gimple_fold_builtin_strncpy): Call
	get_attr_nonstring_decl and handle it.
	* tree-ssa-strlen.c (maybe_diag_stxncpy_trunc): Same.  Improve
	detection of nul-termination.
	(strlen_to_stridx): Change to a pointer.
	(handle_builtin_strlen, handle_builtin_stxncpy): Adjust.
	(pass_strlen::execute): Same.

gcc/testsuite/ChangeLog:

	PR tree-optimization/82945
	* c-c++-common/Wstringop-truncation-2.c: New test.
	* c-c++-common/Wstringop-truncation.c: Adjust.
	* c-c++-common/attr-nonstring-2.c: Adjust.
	* c-c++-common/attr-nonstring-3.c: New test.

From-SVN: r255031

1 files changed, 105 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/Wstringop-truncation-2.c b/gcc/testsuite/c-c++-common/Wstringop-truncation-2.c
new file mode 100644
index 0000000..7b3c182
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wstringop-truncation-2.c
@@ -0,0 +1,105 @@
+/* Verify that 
+   { dg-do compile }
+   { dg-options "-O2 -Wstringop-truncation -Wno-stringop-overflow -ftrack-macro-expansion=0" } */
+
+typedef __SIZE_TYPE__ size_t;
+
+#define stpncpy(d, s, n) __builtin_stpncpy ((d), (s), (n))
+#define strncpy(d, s, n) __builtin_stpncpy ((d), (s), (n))
+
+void sink (void*);
+
+struct A {
+  char arr[3] __attribute__ ((nonstring));
+  char str[3];
+};
+
+struct B { struct A a[3]; int i; };
+struct C { struct B b[3]; int i; };
+
+void stpncpy_arr_1 (struct C *pc, const char *s)
+{
+  stpncpy (pc->b[0].a[0].arr, s, sizeof pc->b[0].a[0].arr);
+  sink (pc->b[0].a[0].arr);
+
+  stpncpy (pc->b[0].a[1].arr, s, sizeof pc->b[0].a[1].arr);
+  sink (pc->b[0].a[1].arr);
+
+  stpncpy (pc->b[0].a[2].arr, s, sizeof pc->b[0].a[2].arr);
+  sink (pc->b[0].a[2].arr);
+
+  stpncpy (pc->b[1].a[0].arr, s, sizeof pc->b[1].a[0].arr);
+  sink (pc->b[1].a[0].arr);
+
+  stpncpy (pc->b[1].a[1].arr, s, sizeof pc->b[1].a[1].arr);
+  sink (pc->b[1].a[1].arr);
+
+  stpncpy (pc->b[1].a[2].arr, s, sizeof pc->b[1].a[2].arr);
+  sink (pc->b[1].a[2].arr);
+
+  stpncpy (pc->b[2].a[0].arr, s, sizeof pc->b[2].a[0].arr);
+  sink (pc->b[2].a[0].arr);
+
+  stpncpy (pc->b[2].a[1].arr, s, sizeof pc->b[2].a[1].arr);
+  sink (pc->b[2].a[1].arr);
+
+  stpncpy (pc->b[2].a[2].arr, s, sizeof pc->b[2].a[2].arr);
+  sink (pc->b[2].a[2].arr);
+}
+
+void stpncpy_str_nowarn_1 (struct C *pc, const char *s)
+{
+  stpncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str)[-1] = 0;   /* { dg-bogus "\\\[-Wstringop-truncation" } */
+}
+
+void stpncpy_str_nowarn_2 (struct C *pc, const char *s)
+{
+  *stpncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str - 1) = 0;   /* { dg-bogus "\\\[-Wstringop-truncation" } */
+}
+
+void stpncpy_str_nowarn_3 (struct C *pc, const char *s)
+{
+  char *d = stpncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str);   /* { dg-bogus "\\\[-Wstringop-truncation" } */
+
+  d[-1] = 0;
+}
+
+void stpncpy_str_nowarn_4 (struct C *pc, const char *s)
+{
+  char *d = stpncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str - 1);   /* { dg-bogus "\\\[-Wstringop-truncation" } */
+
+  *d = 0;
+}
+
+void strncpy_arr_1 (struct C *pc, const char *s)
+{
+  strncpy (pc->b[0].a[0].arr, s, sizeof pc->b[0].a[0].arr);
+  sink (pc->b[0].a[0].arr);
+
+  strncpy (pc->b[0].a[1].arr, s, sizeof pc->b[0].a[1].arr);
+  sink (pc->b[0].a[1].arr);
+
+  strncpy (pc->b[0].a[2].arr, s, sizeof pc->b[0].a[2].arr);
+  sink (pc->b[0].a[2].arr);
+}
+
+void strncpy_str_nowarn_1 (struct C *pc, const char *s)
+{
+  strncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str);   /* { dg-bogus "\\\[-Wstringop-truncation" } */
+
+  pc->b[0].a[0].str[sizeof pc->b[0].a[0].str - 1] = 0;
+}
+
+void strncpy_str_warn_1 (struct C *pc, const char *s)
+{
+  strncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str);   /* { dg-warning "specified bound 3 equals destination size" } */
+
+  pc->b[1].a[0].str[sizeof pc->b[0].a[0].str - 1] = 0;
+}
+
+void strncpy_str_warn_2 (struct C *pc, const char *s)
+{
+  strncpy (pc->b[0].a[0].str, s, sizeof pc->b[0].a[0].str);   /* { dg-warning "specified bound 3 equals destination size" } */
+
+  pc->b[0].a[1].str[sizeof pc->b[0].a[0].str - 1] = 0;
+}