On Wed, Nov 12, 2014 at 1:28 AM, Marek Polacek <pola...@redhat.com> wrote:
> On Tue, Nov 11, 2014 at 11:27:21PM +0530, Prathamesh Kulkarni wrote:
>> I tried the following:
>> struct A { struct B {}; int x; } /* { dg-warning "empty struct has
>> size 0 in C" } */
>> /* { dg-bogus "delcaration
>> does not declare anything" } */
>> but it fails in excess errors.
>> How do I resolve this ?
>
> Try something like
> /* { dg-warning "empty struct has size 0 in C|declaration does not declare
> anything" } */
Thanks, that worked.
>
>> Index: gcc/c/c-decl.c
>> ===================================================================
>> --- gcc/c/c-decl.c (revision 217287)
>> +++ gcc/c/c-decl.c (working copy)
>> @@ -7506,12 +7506,28 @@
>> /* Finish up struct info used by -Wc++-compat. */
>>
>> static void
>> -warn_cxx_compat_finish_struct (tree fieldlist)
>> +warn_cxx_compat_finish_struct (tree fieldlist, enum tree_code code,
>> location_t record_loc)
>
> This line is too long, please indent the last argument properly on
> next line.
>
>> unsigned int ix;
>> tree x;
>> struct c_binding *b;
>>
>> + if (fieldlist == NULL_TREE)
>> + {
>> + if (code == RECORD_TYPE)
>> + {
>> + warning_at (record_loc, OPT_Wc___compat,
>> + "empty struct has size 0 in C, size 1 in C++");
>> + }
>> + else if (code == UNION_TYPE)
>> + {
>> + warning_at (record_loc, OPT_Wc___compat,
>> + "empty union has size 0 in C, size 1 in C++");
>> + }
>
> Drop the { } around warning_at's.
Done.
>
>> + else
>> + gcc_unreachable ();
>> + }
>> +
>
> I don't think this is needed.
Removed.
Is this version okay ?
[gcc/c]
* c-decl.c (warn_cxx_compat_finish_struct): New parameters code, record_loc.
Warn for empty struct.
(finish_struct): Pass TREE_CODE (t) and loc to
warn_cxx_compat_finish_struct.
[gcc/testsuite/gcc.dg]
* Wcxx-compat-22.c: New test-case.
Thank you,
Prathamesh
>
> Thanks,
>
> Marek
Index: gcc/c/c-decl.c
===================================================================
--- gcc/c/c-decl.c (revision 217287)
+++ gcc/c/c-decl.c (working copy)
@@ -7506,12 +7506,23 @@
/* Finish up struct info used by -Wc++-compat. */
static void
-warn_cxx_compat_finish_struct (tree fieldlist)
+warn_cxx_compat_finish_struct (tree fieldlist, enum tree_code code,
+ location_t record_loc)
{
unsigned int ix;
tree x;
struct c_binding *b;
+ if (fieldlist == NULL_TREE)
+ {
+ if (code == RECORD_TYPE)
+ warning_at (record_loc, OPT_Wc___compat,
+ "empty struct has size 0 in C, size 1 in C++");
+ else
+ warning_at (record_loc, OPT_Wc___compat,
+ "empty union has size 0 in C, size 1 in C++");
+ }
+
/* Set the C_TYPE_DEFINED_IN_STRUCT flag for each type defined in
the current struct. We do this now at the end of the struct
because the flag is used to issue visibility warnings, and we
@@ -7844,7 +7855,7 @@
DECL_EXPR, build_decl (loc, TYPE_DECL, NULL, t)));
if (warn_cxx_compat)
- warn_cxx_compat_finish_struct (fieldlist);
+ warn_cxx_compat_finish_struct (fieldlist, TREE_CODE (t), loc);
struct_parse_info->struct_types.release ();
struct_parse_info->fields.release ();
Index: gcc/testsuite/gcc.dg/Wcxx-compat-22.c
===================================================================
--- gcc/testsuite/gcc.dg/Wcxx-compat-22.c (revision 0)
+++ gcc/testsuite/gcc.dg/Wcxx-compat-22.c (working copy)
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-Wc++-compat" } */
+struct A {}; /* { dg-warning "empty struct has size 0 in C" } */
+union B {}; /* { dg-warning "empty union has size 0 in C" } */
+struct C { struct D {}; int x; }; /* { dg-warning "empty struct has size 0 in C|declaration does not declare anything" } */
+struct E { union F {}; int x; }; /* { dg-warning "empty union has size 0 in C|declaration does not declare anything" } */
+union G { union H {}; int x; }; /* { dg-warning "empty union has size 0 in C|declaration does not declare anything" } */
+union I { struct J {}; int x; }; /* { dg-warning "empty struct has size 0 in C|declaration does not declare anything" } */
