Doug Gregor wrote:
PR c++/34935 illustrates a problem with the way attributes interact
with type identity. The example in question looks something like this:
typedef int X __attribute((may_alias));
void foo(X);
void foo(int);
Note that this is pretty tied up with Mark Mitchell's discussion of
semantic and non-semantic attributes, here:
http://gcc.gnu.org/ml/gcc/2006-10/msg00318.html
The may_alias attribute is a semantic attribute as it is specifically
designed to affect code-generation.
Using the message you mention, this means that "X" is distinct from
"int" -- which is what Richard and Jakub indicate as well, based on what
the middle-end does.
Also, that message says:
It is invalid to do anything that would require either type_info or a mangled name for "Q",
including using it as an argument to typeid, thowing an exception of a type involving "Q", or
declaring a template to take a parameter of a type involving "Q".
So, that means that you can't have any C++ functions with external
linkage involving "X". Of course, as that message says:
We could relax some of these restrictions in future, if we add mangling support
for attributes.
But, yes, if we need to mangle these types, we need to have a mangling
for attributes.
--
Mark Mitchell
CodeSourcery
[EMAIL PROTECTED]
(650) 331-3385 x713
