* Florian Weimer:
> It turns out that permerror_opt is not directly usable for
> -fpermissive in the C front end. The front end uses pedwarn
> extensively, and pedwarns are not overridable by -Wno-* options,
> yet permerrors are. Add new pedpermerror helpers that turn into
> pedwarns if -pedantic-errors is active.
>
> Due to the dependency on flag_pedantic_errors, the new helpers
> are specific to the C-family front ends. For implementing the
> rich location variant, export emit_diagnostic_valist from
> gcc/diagnostic.cc in parallel to its location_t variant.
>
> gcc/
>
> * diagnostic-core.h (emit_diagnostic_valist): Declare function.
> * diagnostic.cc (emit_diagnostic_valist): Define it.
>
> gcc/c-family/
>
> * c-common.h (pedpermerror): Declare functions.
> * c-warn.cc (pedpermerror): Define them.
Jason suggested off-list that this shouldn't be necessary, and the
description of -pedantic-errors is wrong (it is possible to undo
-pedantic-errors effects with -Wno-error=…). The permerror_opt
interface should already do what I need.
It turns out that I was very unlucky and picked -Wreturn-type for my
tests.
This:
long i = "abc";
volatile j;
int f (void) { return; }
Gives, with GCC 13:
$ gcc -pedantic-errors -Wno-error=implicit-int -Wno-error=int-conversion -Wno-error=return-type test.c
test.c:1:10: warning: initialization of ‘long int’ from ‘char *’ makes integer from pointer without a cast [-Wint-conversion]
1 | long i = "abc";
| ^~~~~
test.c:2:10: warning: type defaults to ‘int’ in declaration of ‘j’ [-Wimplicit-int]
2 | volatile j;
| ^
test.c: In function ‘f’:
test.c:3:16: error: ‘return’ with no value, in function returning non-void
3 | int f (void) { return; }
| ^~~~~~
test.c:3:5: note: declared here
3 | int f (void) { return; }
| ^
This happens because we drop the OPT_Wreturn_type in some cases:
if (flag_isoc99)
warned_here = pedwarn
(loc, warn_return_type >= 0 ? OPT_Wreturn_type : 0,
"%<return%> with no value, in function returning non-void");
else
warned_here = warning_at
(loc, OPT_Wreturn_type,
"%<return%> with no value, in function returning non-void");
And for the other direction:
if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
warned_here = pedwarn
(xloc, warn_return_type >= 0 ? OPT_Wreturn_type : 0,
"%<return%> with a value, in function returning void");
I think with the -Wreturn-mismatch split, we can drop the
warn_return_type >= 0 condition, and then permerror_opt should indeed
do the right thing.
I'll write the kitchen sink test now, use that to verify this theory,
and repost as appropriate.
Thanks,
Florian
@@ -1486,6 +1486,10 @@ extern void warn_for_address_or_pointer_of_packed_member (tree, tree);
extern void warn_parm_array_mismatch (location_t, tree, tree);
extern void maybe_warn_sizeof_array_div (location_t, tree, tree, tree, tree);
extern void do_warn_array_compare (location_t, tree_code, tree, tree);
+extern bool pedpermerror (location_t, int, const char *,
+ ...) ATTRIBUTE_GCC_DIAG(3,4);
+extern bool pedpermerror (rich_location *, int, const char *,
+ ...) ATTRIBUTE_GCC_DIAG(3,4);
/* Places where an lvalue, or modifiable lvalue, may be required.
Used to select diagnostic messages in lvalue_error and
@@ -3932,3 +3932,37 @@ check_for_xor_used_as_pow (location_t lhs_loc, tree lhs_val,
lhs_uhwi, lhs_uhwi);
}
}
+
+/* If !flag_pedantic_errors, equivalent to permerror_opt, otherwise to
+ pedwarn. */
+
+bool
+pedpermerror (location_t location, int opt, const char *gmsgid, ...)
+{
+ auto_diagnostic_group d;
+ va_list ap;
+ va_start (ap, gmsgid);
+ rich_location richloc (line_table, location);
+ bool ret = emit_diagnostic_valist (flag_pedantic_errors
+ ? DK_PEDWARN : DK_PERMERROR,
+ location, opt, gmsgid, &ap);
+ va_end (ap);
+ return ret;
+}
+
+/* Same as "pedpermerror" above, but at RICHLOC. */
+
+bool
+pedpermerror (rich_location *richloc, int opt, const char *gmsgid, ...)
+{
+ gcc_assert (richloc);
+
+ auto_diagnostic_group d;
+ va_list ap;
+ va_start (ap, gmsgid);
+ bool ret = emit_diagnostic_valist (flag_pedantic_errors
+ ? DK_PEDWARN : DK_PERMERROR,
+ richloc, opt, gmsgid, &ap);
+ va_end (ap);
+ return ret;
+}
@@ -121,6 +121,9 @@ extern bool emit_diagnostic (diagnostic_t, location_t, int,
const char *, ...) ATTRIBUTE_GCC_DIAG(4,5);
extern bool emit_diagnostic (diagnostic_t, rich_location *, int,
const char *, ...) ATTRIBUTE_GCC_DIAG(4,5);
+extern bool emit_diagnostic_valist (diagnostic_t, rich_location *, int,
+ const char *,
+ va_list *) ATTRIBUTE_GCC_DIAG (4,0);
extern bool emit_diagnostic_valist (diagnostic_t, location_t, int, const char *,
va_list *) ATTRIBUTE_GCC_DIAG (4,0);
extern bool seen_error (void);
@@ -1829,6 +1829,13 @@ emit_diagnostic_valist (diagnostic_t kind, location_t location, int opt,
return diagnostic_impl (&richloc, NULL, opt, gmsgid, ap, kind);
}
+bool
+emit_diagnostic_valist (diagnostic_t kind, rich_location *richloc, int opt,
+ const char *gmsgid, va_list *ap)
+{
+ return diagnostic_impl (richloc, NULL, opt, gmsgid, ap, kind);
+}
+
/* An informative note at LOCATION. Use this for additional details on an error
message. */
void