[PATCH] Initial support for __sptr and __uptr

[Aaron Ballman]

On Tue, May 14, 2013 at 8:42 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> On Tue, May 14, 2013 at 5:41 PM, Aaron Ballman <aaron at aaronballman.com>
> wrote:
>>
>> On Tue, May 14, 2013 at 8:34 PM, Richard Smith <richard at metafoo.co.uk>
>> wrote:
>> > On Tue, May 14, 2013 at 4:07 PM, Charles Davis <cdavis5x at gmail.com>
>> > wrote:
>> >>
>> >>
>> >> On May 14, 2013, at 4:26 PM, Aaron Ballman wrote:
>> >> >
>> >> >> Do __sptr and __uptr get different manglings?
>> >> >
>> >> > They do:
>> >> >
>> >> > void func( int * __ptr32 p ) {}
>> >> > void func2( int * __ptr64 p ) {}
>> >> >
>> >> > PUBLIC ?func@@YAXPAH at Z ; func
>> >> > PUBLIC ?func2@@YAXPEAH at Z ; func2
>> >> >
>> >> > Namely, the presence of E (rnk pointed this out previously).
>> >> He was asking about __sptr and __uptr :). They don't by the way:
>> >>
>> >> > cl /c test.cpp
>> >> [extraneous banner output omitted]
>> >> > dumpbin /symbols test.obj
>> >> [...]
>> >> 00F 00000010 SECT4  notype ()    External     | ?func@@YAXPAH at Z (void
>> >> __cdecl func(int *))
>> >> 010 00000020 SECT4  notype ()    External     | ?func2@@YAXPAH at Z (void
>> >> __cdecl func2(int *))
>> >
>> >
>> > Thanks. One more thing:
>> >
>> > template<typename T> void f(void **p, T *q) { *p = *q; }
>> >
>> > void *g(int *__ptr32 __sptr a) {
>> >   void *result;
>> >   f(&result, &a);
>> >   return result;
>> > }
>> > void *h(char *__ptr32 __uptr a) {
>> >   void *result;
>> >   f(&result, &a);
>> >   return result;
>> > }
>> >
>> > int main() {
>> >   printf("%p\n", g((int *__ptr32 __sptr)0xdeadbeef));
>> >   printf("%p\n", h((char *__ptr32 __uptr)0xdeadbeef));
>> > }
>> >
>> > Does one of these get sign-extended and the other one get zero-extended?
>>
>> The first is sign extended, and the second is zero extended in 64-bit.
>
>
> What happens if you change the two 'char's to 'int's?

Both sign extend.  Is that due to the template instantiation?

~Aaron