On Sat, Jan 26, 2019 at 01:35:05PM +0100, Jakub Jelinek wrote:
> On Sat, Jan 26, 2019 at 01:25:04AM +0000, Joseph Myers wrote:
> > It's also broken the build of the glibc testsuite, e.g.:
> >
> > ../time/time.h:88:15: error: mismatch in argument 1 type of built-in
> > function 'strftime'; expected 'char *'
> > [-Werror=builtin-declaration-mismatch]
> > 88 | extern size_t strftime (char *__restrict __s, size_t __maxsize,
> >
> > (presence or absence of qualifiers on a parameter is not part of the
> > function type and should not be compared here).
>
> There are several further issues, even after fixing the toplevel qualifiers on
> arguments as well as return type + fixing up the testcases, there is another
> problem, the code has the magic handling only for fileptr_type_node, but we
> actually need handling for all builtin_structptr_types struct types,
> otherwise e.g. for strftime we warn that the last argument should not be
> const struct tm *, but const void *, when it actually should be const struct
> tm *.
It is actually worse than that, because unlike C++, in C fileptr_type_node
is a mere void * and const_tm_ptr_type_node a mere const_ptr_type_node.
So, on
/* PR c/86125 */
/* { dg-do compile } */
/* { dg-options "-Wbuiltin-declaration-mismatch -Wextra
-Wno-ignored-qualifiers" } */
typedef __SIZE_TYPE__ size_t;
struct FILE;
struct tm;
struct fenv_t;
struct fexcept_t;
typedef struct FILE FILE;
typedef struct fenv_t fenv_t;
typedef struct fexcept_t fexcept_t;
typedef const int cint;
size_t strftime (char *__restrict, const size_t, const char *__restrict,
/* { dg-bogus "mismatch in argument 1 type of built-in function" } */
const struct tm *__restrict) __attribute__((nothrow));
int fprintf (struct FILE *, const char *const, ...);
/* { dg-bogus "mismatch in argument 2 type of built-in function" } */
cint putc (int, struct FILE *);
/* { dg-bogus "mismatch in return type of built-in function" } */
cint fegetenv (fenv_t *);
/* { dg-bogus "mismatch in argument 1 type of built-in function" } */
cint fesetenv (const fenv_t *);
/* { dg-bogus "mismatch in return type of built-in function" } */
int fegetexceptflag (fexcept_t *, const int);
/* { dg-bogus "mismatch in argument 1 type of built-in function" } */
int fesetexceptflag (const fexcept_t *, const int);
/* { dg-bogus "mismatch in argument 1 type of built-in function" } */
we get among all the other bogus warnings
Wbuiltin-declaration-mismatch-11.c:21:5: warning: mismatch in argument 1 type
of built-in function ‘fegetexceptflag’; expected ‘struct FILE *’
[-Wbuiltin-declaration-mismatch]
21 | int fegetexceptflag (fexcept_t *, const int); /* { dg-bogus
"mismatch in argument 1 type of built-in function" } */
| ^~~~~~~~~~~~~~~
Suggesting one uses struct FILE * argument to fegetexceptflag is not a very
good suggestion.
Jakub
