[cxx-abi-dev] Mangling of calling convention attributes

[Jason Merrill]

On 05/05/2015 05:00 PM, Jason Merrill wrote:
> ia32 targets support a variety of calling conventions, which correspond
> to various attributes (cdecl, stdcall, regparm, etc.).  Currently these
> are not represented in mangling, which leads to problems with template
> instantiation; I'm thinking about starting to treat them as vendor
> qualifiers, so given
>
> extern "C" void abort();
> template <typename F, typename T>
> void IndirectExternCall(F f, T t1, T t2) {
>    typedef F (*WrapF)(F);
>    f (t1, t2);
> }
>
> __attribute__((regparm(3), stdcall))
> void regparm_func (int i, int j)
> {
>    if (i != 24 || j != 42)
>      abort();
> }
>
> void normal_func (int i, int j)
> {
>    if (i != 24 || j != 42)
>      abort();
> }
>
> int main()
> {
>    IndirectExternCall (regparm_func, 24, 42);
>    IndirectExternCall (normal_func, 24, 42);
> }
>
> the two instantiations of IndirectExternCall would be mangled
> differently.  Currently my prototype mangles stdcall as U7stdcall and
> regparm(3) as U11regparmLi3E, i.e. mangling the attribute argument like
> a template argument.

So the first instantiation is

_Z18IndirectExternCallIPU7stdcallU11regparmLi3EFviiEiEvT_T0_S3_

Jason