libcilkrts/runtime/reducer_impl.h

   1 /* reducer_impl.h                  -*-C++-*-
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   3  *************************************************************************
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  48  **************************************************************************/
  49
  50 /**
  51  * @file reducer_impl.h
  52  *
  53  * @brief Functions to implement reducers in the runtime.
  54  */
  55
  56 #ifndef INCLUDED_REDUCER_IMPL_DOT_H
  57 #define INCLUDED_REDUCER_IMPL_DOT_H
  58
  59 #include <cilk/common.h>
  60 #include <internal/abi.h>
  61 #include "rts-common.h"
  62
  63 __CILKRTS_BEGIN_EXTERN_C
  64
  65 /**
  66  * Construct an empty reducer map from the memory pool associated with the
  67  * given worker.  This reducer map must be destroyed before the worker's
  68  * associated global context is destroyed.
  69  *
  70  * @param w __cilkrts_worker the cilkred_map is being created for.
  71  *
  72  * @return Pointer to the initialized cilkred_map.
  73  */
  74 COMMON_SYSDEP
  75 cilkred_map *__cilkrts_make_reducer_map(__cilkrts_worker *w);
  76
  77 /**
  78  * Destroy a reducer map.  The map must have been allocated from the worker's
  79  * global context and should have been allocated from the same worker.
  80  *
  81  * @param w __cilkrts_worker the cilkred_map was created for.
  82  * @param h The cilkred_map to be deallocated.
  83  */
  84 COMMON_SYSDEP
  85 void __cilkrts_destroy_reducer_map(__cilkrts_worker *w,
  86                                    cilkred_map *h);
  87
  88 /**
  89  * Set the specified reducer map as the leftmost map if is_leftmost is true,
  90  * otherwise, set it to not be the leftmost map.
  91  *
  92  * @param h The cilkred_map to be modified.
  93  * @param is_leftmost true if the reducer map is leftmost.
  94  */
  95 COMMON_SYSDEP
  96 void __cilkrts_set_leftmost_reducer_map(cilkred_map *h,
  97                                         int is_leftmost);
  98
  99 /**
 100  * Merge reducer map RIGHT_MAP into LEFT_MAP and return the result of the
 101  * merge.  Both maps must be allocated from the global context associated
 102  * with the specified worker.  The returned reducer map must be destroyed
 103  * before the worker's associated global context is destroyed.
 104  *
 105  * If two cilkred_maps are specified, one will be destroyed and the other
 106  * one will be returned as the merged cilkred_map.
 107  *
 108  * When reducers can contain nested parallelism, execution can return
 109  * on a different worker than when it started (but still using the
 110  * same stack).
 111  *
 112  * Upon return, *w_ptr stores the pointer to the worker that execution
 113  * returns on.
 114  *
 115  * @param w_ptr      Pointer to the currently executing worker.
 116  * @param left_map   The left cilkred_map.
 117  * @param right_map  The right cilkred_map.
 118  *
 119  * @return pointer to merged cilkred_map.
 120  */
 121 extern
 122 cilkred_map *merge_reducer_maps(__cilkrts_worker **w_ptr,
 123                                 cilkred_map *left_map,
 124                                 cilkred_map *right_map);
 125
 126 /**
 127  * Similar to merge_reducer_maps(), except that after merging
 128  * RIGHT_MAP into LEFT_MAP, it repeatedly merges (*w_ptr)->reducer_map
 129  * into LEFT_MAP.  This procedure ensures that any new reducers
 130  * created by the reductions themselves also get merged into LEFT_MAP.
 131  */
 132 extern
 133 cilkred_map *repeated_merge_reducer_maps(__cilkrts_worker **w_ptr,
 134                                          cilkred_map *left_map,
 135                                          cilkred_map *right_map);
 136
 137 __CILKRTS_END_EXTERN_C
 138
 139 #endif // ! defined(INCLUDED_REDUCER_IMPL_DOT_H)