On Mon, May 23, 2016 at 5:26 AM, Basile Starynkevitch
<bas...@starynkevitch.net> wrote:
> Hello All,
>
> As I explained in https://gcc.gnu.org/ml/jit/2016-q2/msg00042.html it is
> difficult (or tricky without using dirty tricks involving the GCC plugin
> headers) to use GCCJIT to emit code equivalent to the following C file:
>
> extern int a;
> int get_atomic_a (void) {
> return __atomic_load_n (&a, __ATOMIC_SEQ_CST);
> }
>
> The issue is that __ATOMIC_SEQ_CST is a magic preprocessor (but
> non-standard!) symbol which might not be available
> (or might have a different value) in the C code for GCCJIT building such an
> AST.
>
> So we need a function to retrieve some magic integral value from the GCCJIT
> compiler.
Huh? Why can't you just use the enum:
enum memmodel
{
MEMMODEL_RELAXED = 0,
MEMMODEL_CONSUME = 1,
MEMMODEL_ACQUIRE = 2,
MEMMODEL_RELEASE = 3,
MEMMODEL_ACQ_REL = 4,
MEMMODEL_SEQ_CST = 5,
MEMMODEL_LAST = 6,
MEMMODEL_SYNC_ACQUIRE = MEMMODEL_ACQUIRE | MEMMODEL_SYNC,
MEMMODEL_SYNC_RELEASE = MEMMODEL_RELEASE | MEMMODEL_SYNC,
MEMMODEL_SYNC_SEQ_CST = MEMMODEL_SEQ_CST | MEMMODEL_SYNC
};
For the values? I don't understand why you need to have a direct
relationship to preprocessed macros to these values here.
Have your own lookup table inside your own JIT rather than a generic
way of doing it.
Having a generic way seems more incorrect way of doing it and even
says that the JIT is supposed to JITting C code but it is not JITing C
code.
Thanks,
Andrew Pinski
>
> The attached patch (relative to trunk svn 236583) is a first attempt to
> solve that issue
> (and also give ability to query some other magic numbers).
>
> Proposed ChangeLog entry (in gcc/jit/)
>
> 2016-05-23 Basile Starynkevitch <bas...@starynkevitch.net>
> * libgccjit.h (LIBGCCJIT_HAVE_gcc_jit_magic_int): New macro.
> (gcc_jit_magic_int): New public function declaration.
>
> * libgccjit.c: Include "cppbuiltin.h", "options.h", "flag-types.h"
> (gcc_jit_magic_int): New function.
>
> * libgccjit.map: Add gcc_jit_magic_int to LIBGCCJIT_ABI_6.
>
> Comments (or an ok to commit) are welcome. (I am not sure that
> __SANITIZE_ADDRESS__ is correctly handled,
> because I would believe that optimization flags are not globals in GCCJIT)
>
> Regards.
>
> --
> Basile STARYNKEVITCH http://starynkevitch.net/Basile/
> email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
> 8, rue de la Faiencerie, 92340 Bourg La Reine, France
> *** opinions {are only mine, sont seulement les miennes} ***
>
