[Bug c++/17542] New: Visibility attribute ignored when it precedes class head

[austern at apple dot com]

Consider the following file:
__attribute__((visibility("default"))) struct foo { virtual ~foo(); };
struct bar { virtual ~bar(); } __attribute__((visibility("default")));
foo::~foo() { }
bar::~bar() { }

My expectation would be that classes foo and bar would both get default visibility.  That's not what 
happens:
[isolde:tmp]$ /work/root/bin/g++ -fvisibility=hidden -c v5.cc
[isolde:tmp]$ nm -m v5.o
00000208 (__TEXT,__text) external __ZN3barD0Ev
00000000 (absolute) external __ZN3barD0Ev.eh
000001a0 (__TEXT,__text) external __ZN3barD1Ev
00000000 (absolute) external __ZN3barD1Ev.eh
00000138 (__TEXT,__text) external __ZN3barD2Ev
00000000 (absolute) external __ZN3barD2Ev.eh
000000d0 (__TEXT,__text) private external __ZN3fooD0Ev
00000000 (absolute) private external __ZN3fooD0Ev.eh
00000068 (__TEXT,__text) private external __ZN3fooD1Ev
00000000 (absolute) private external __ZN3fooD1Ev.eh
00000000 (__TEXT,__text) private external __ZN3fooD2Ev
00000000 (absolute) private external __ZN3fooD2Ev.eh
00000270 (__DATA,__datacoal_nt) weak external __ZTI3bar
00000280 (__DATA,__datacoal_nt) weak private external __ZTI3foo
00000278 (__DATA,__datacoal_nt) weak external __ZTS3bar
00000288 (__DATA,__datacoal_nt) weak private external __ZTS3foo
000002a0 (__DATA,__const) external __ZTV3bar
00000290 (__DATA,__const) private external __ZTV3foo
         (undefined) external __ZTVN10__cxxabiv117__class_type_infoE
         (undefined [lazy bound]) external __ZdlPv
         (undefined) external dyld_stub_binding_helper
[isolde:tmp]$ 

This is certainly wrong.  If putting the visibility attribute at the beginning of the class definition is 
syntactly valid, then that visibility should be respected.  If this is a syntax error then it should be 
diagnosed as such.  Silently ignoring the attribute is wrong.

-- 
           Summary: Visibility attribute ignored when it precedes class head
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: austern at apple dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: powerpc-apple-darwin7.5.0
  GCC host triplet: powerpc-apple-darwin7.5.0
GCC target triplet: powerpc-apple-darwin7.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17542