Building the following testcase fails with G++ 4.5 and later.
G++ 4.4 works fine.
struct JSString
{
unsigned char mLength;
static JSString unitStringTable[];
};
JSString JSString::unitStringTable[] __attribute__ ((aligned (8))) = { 1 };
int bug [__alignof__ (JSString::unitStringTable) >= 8 ? 1 : -1];
The test case is reduced from Mozilla, where the bug sometimes causes the
JavaScript interpreter to crash. See also:
https://bugzilla.mozilla.org/show_bug.cgi?id=582593
The problem appears to be that cp-decl.c:duplicate_decls fails to merge
the DECL_USER_ALIGN flag from the definition into the declaration.
This bug was introduced by the following patch:
http://gcc.gnu.org/ml/gcc-patches/2009-06/msg00763.html
Before that patch, the DECL_USER_ALIGN flag was part of a block copied in whole
via memcpy by duplicate_decls. The patch moved that flag to another location
outside that block, so it is no longer copied ...
--
Summary: [4.5/4.6 regression] Aligned attribute on static class
member definition ignored
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: uweigand at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45112
