/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#ifndef MPIR_REFCOUNT_POBJ_H_INCLUDED

#define MPIR_REFCOUNT_POBJ_H_INCLUDED

/* define a type for the completion counter */

#include "opa_primitives.h"

typedef OPA_int_t MPIR_cc_t;

/* implies no barrier, since this routine should only be used for request

 * initialization */

static inline void MPIR_cc_set(MPIR_cc_t * cc_ptr, int val)

{

    if (val == 0) {

        /* values other than 0 do not enforce any ordering, and therefore do not

         * start a HB arc */

        /* MT FIXME using cc_set in this way is sloppy.  Sometimes the caller

         * really does know that the cc value may cleared, but more likely this

         * is just a hack to avoid the work of figuring out what the cc value

         * currently is and decrementing it instead. */

        /* barrier ensures that any state written before indicating completion is

         * seen by the thread polling on the cc.  If OPA adds store-release

         * semantics, we can convert to that instead. */

        OPA_write_barrier();

        MPL_VG_ANNOTATE_HAPPENS_BEFORE(cc_ptr);

    }

#if defined(MPL_VG_AVAILABLE)

    /* MT subtle: store_int is actually safe to use, but Helgrind/DRD/TSan all

     * view the store/load pair as a race.  Using an atomic operation for the

     * store side makes all three happy.  DRD & TSan also support

     * ANNOTATE_BENIGN_RACE, but Helgrind does not. */

    OPA_swap_int(cc_ptr, val);

#else

    OPA_store_int(cc_ptr, val);

#endif

}

ATTRIBUTE((unused))

static inline int MPIR_cc_is_complete(MPIR_cc_t * cc_ptr)

{

    int complete;

    complete = (0 == OPA_load_int(cc_ptr));

    if (complete) {

        MPL_VG_ANNOTATE_HAPPENS_AFTER(cc_ptr);

        OPA_read_barrier();

    }

    return complete;

}

/* incomplete_==TRUE iff the cc > 0 after the decr */

#define MPIR_cc_decr(cc_ptr_, incomplete_)                      \

    do {                                                        \

        int ctr_;                                               \

        OPA_write_barrier();                                    \

        MPL_VG_ANNOTATE_HAPPENS_BEFORE(cc_ptr_);                \

        ctr_ = OPA_fetch_and_decr_int(cc_ptr_);                 \

        MPIR_Assert(ctr_ >= 1);                                 \

        *(incomplete_) = (ctr_ != 1);                           \

        /* TODO check if this HA is actually necessary */       \

        if (!*(incomplete_)) {                                  \

            MPL_VG_ANNOTATE_HAPPENS_AFTER(cc_ptr_);             \

        }                                                       \

    } while (0)

/* MT FIXME does this need a HB/HA annotation?  This macro is only used for

 * cancel_send right now. */

/* was_incomplete_==TRUE iff the cc==0 before the decr */

#define MPIR_cc_incr(cc_ptr_, was_incomplete_)                  \

    do {                                                        \

        *(was_incomplete_) = OPA_fetch_and_incr_int(cc_ptr_);   \

    } while (0)

#define MPIR_cc_get(cc_) OPA_load_int(&(cc_))

/* "publishes" the obj with handle value (handle_) via the handle pointer

 * (hnd_lval_).  That is, it is a version of the following statement that fixes

 * memory consistency issues:

 *     (hnd_lval_) = (handle_);

 *

 * assumes that the following is always true: typeof(*hnd_lval_ptr_)==int

 */

/* This could potentially be generalized beyond MPI-handle objects, but we

 * should only take that step after seeing good evidence of its use.  A general

 * macro (that is portable to non-gcc compilers) will need type information to

 * make the appropriate volatile cast. */

/* Ideally _GLOBAL would use this too, but we don't want to count on OPA

 * availability in _GLOBAL mode.  Instead the GLOBAL critical section should be

 * used. */

#define MPIR_OBJ_PUBLISH_HANDLE(hnd_lval_, handle_)                     \

    do {                                                                \

        if (MPIR_ThreadInfo.isThreaded) {                               \

            /* wmb ensures all read-only object field values are seen before the */ \

            /* handle value is seen at the application level */         \

            OPA_write_barrier();                                        \

            /* volatile ensures lval is not speculatively read or written */ \

            *(volatile int *)&(hnd_lval_) = (handle_);                  \

        }                                                               \

        else {                                                          \

            (hnd_lval_) = (handle_);                                    \

        }                                                               \

    } while (0)

#endif /* MPIR_REFCOUNT_POBJ_H_INCLUDED */