Hi Jakub,
this is a new version of the structure element mapping patch for OpenMP 5.0
requirement
changes.
This one uses the approach you've outlined in your concept patch [1], basically
to
use more special REFCOUNT_* values to mark them, and link following structure
element
splay_tree_keys back to the first key's refcount.
[1] https://gcc.gnu.org/pipermail/gcc-patches/2020-October/557622.html
Implementation notes of the attached patch:
(1) This patch solves the 5.0 requirements of "not already
incremented/decremented
because of the effect of a map clause on the construct" by pulling in
libgomp/hashtab.h
and using htab_t as a pointer set. A "htab_t *refcount_set" is added in
map/unmap
routines to track the processing status of the uintptr_t* addresses of refcount
fields in splay_tree_keys.
* Currently this patch is using the same htab_create/htab_free routines
like in task.c.
I toyed with creating a 'htab_alloca' macro (allocating a fixed size
htab) to speed
things further, but decided to play it safer for the current patch.
(2) Because of the use of pointer-to-refcounts as the basis, and structure
element
siblings all share a same refcount, uniform increment/decrement without
repeating is
also naturally achieved.
(3) Because of the need to remove whole structure element sibling sequences out
of
context, it appears we need to mark the first/last of such a sequence. You'll
see that
the special REFCOUNT_* values have been expanded a bit more than your concept
patch
(at some point we should think about stop abusing it and add a proper flags
word)
(4) The new increment/decrement routines combine most of the new refcount_set
lookup
code with the refcount adjusting. For the decrement routine, "copy" and
"removal" are
now separate return values, since for structure element sequences, even when
signalling
"removal" you may still need to finish the "copy" work of following
target_var_descs.
(5) There are some re-organizing changes to oacc-parallel.c and oacc-mem.c, but
most
of the code that matters is in target.c.
(6) New testcases have been added to reflect the cases discussed on omp-lang
list.
This patch has been tested for libgomp with no regressions on x86_64-linux with
nvptx offloading. Since I submitted the first "v1" patch long ago, is this okay
to be
considered as committable now after approval?
Thanks,
Chung-Lin
2020-12-04 Chung-Lin Tang <clt...@codesourcery.com>
libgomp/
* hashtab.h (htab_clear): New function with initialization code
factored out from...
(htab_create): ...here, adjust to use htab_clear function.
* libgomp.h (REFCOUNT_SPECIAL): New symbol to denote range of
special refcount values, add comments.
(REFCOUNT_INFINITY): Adjust definition to use REFCOUNT_SPECIAL.
(REFCOUNT_LINK): Likewise.
(REFCOUNT_STRUCTELEM): New special refcount range for structure
element siblings.
(REFCOUNT_STRUCTELEM_P): Macro for testing for structure element
sibling maps.
(REFCOUNT_STRUCTELEM_FLAG_FIRST): Flag to indicate first sibling.
(REFCOUNT_STRUCTELEM_FLAG_LAST): Flag to indicate last sibling.
(REFCOUNT_STRUCTELEM_FIRST_P): Macro to test _FIRST flag.
(REFCOUNT_STRUCTELEM_LAST_P): Macro to test _LAST flag.
(struct splay_tree_key_s): Add structelem_refcount and
structelem_refcount_ptr fields into a union with dynamic_refcount.
Add comments.
(gomp_map_vars): Delete declaration.
(gomp_map_vars_async): Likewise.
(gomp_unmap_vars): Likewise.
(gomp_unmap_vars_async): Likewise.
(goacc_map_vars): New declaration.
(goacc_unmap_vars): Likewise.
* oacc-mem.c (acc_map_data): Adjust to use goacc_map_vars.
(goacc_enter_datum): Likewise.
(goacc_enter_data_internal): Likewise.
* oacc-parallel.c (GOACC_parallel_keyed): Adjust to use goacc_map_vars
and goacc_unmap_vars.
(GOACC_data_start): Adjust to use goacc_map_vars.
(GOACC_data_end): Adjust to use goacc_unmap_vars.
* target.c (hash_entry_type): New typedef.
(htab_alloc): New function hook for hashtab.h.
(htab_free): Likewise.
(htab_hash): Likewise.
(htab_eq): Likewise.
(hashtab.h): Add file include.
(gomp_increment_refcount): New function.
(gomp_decrement_refcount): Likewise.
(gomp_map_vars_existing): Add refcount_set parameter, adjust to use
gomp_increment_refcount.
(gomp_map_fields_existing): Add refcount_set parameter, adjust calls
to gomp_map_vars_existing.
(gomp_map_vars_internal): Add refcount_set parameter, add local openmp_p
variable to guard OpenMP specific paths, adjust calls to
gomp_map_vars_existing, add structure element sibling splay_tree_key
sequence creation code, adjust Fortran map case to avoid increment
under OpenMP.
(gomp_map_vars): Adjust to static, add refcount_set parameter, manage
local refcount_set if caller passed in NULL, adjust call to
gomp_map_vars_internal.
(gomp_map_vars_async): Adjust and rename into...
(goacc_map_vars): ...this new function, adjust call to
gomp_map_vars_internal.
(gomp_remove_splay_tree_key): New function with code factored out from
gomp_remove_var_internal.
(gomp_remove_var_internal): Add code to handle removing multiple
splay_tree_key sequence for structure elements, adjust code to use
gomp_remove_splay_tree_key for splay-tree key removal.
(gomp_unmap_vars_internal): Add refcount_set parameter, adjust to use
gomp_decrement_refcount.
(gomp_unmap_vars): Adjust to static, add refcount_set parameter, manage
local refcount_set if caller passed in NULL, adjust call to
gomp_unmap_vars_internal.
(gomp_unmap_vars_async): Adjust and rename into...
(goacc_unmap_vars): ...this new function, adjust call to
gomp_unmap_vars_internal.
(GOMP_target): Manage refcount_set and adjust calls to gomp_map_vars and
gomp_unmap_vars.
(GOMP_target_ext): Likewise.
(gomp_target_data_fallback): Adjust call to gomp_map_vars.
(GOMP_target_data): Likewise.
(GOMP_target_data_ext): Likewise.
(GOMP_target_end_data): Adjust call to gomp_unmap_vars.
(gomp_exit_data): Add refcount_set parameter, adjust to use
gomp_decrement_refcount, adjust to queue splay-tree keys for removal
after main loop.
(GOMP_target_enter_exit_data): Manage refcount_set and adjust calls to
gomp_map_vars and gomp_exit_data.
(gomp_target_task_fn): Likewise.
* testsuite/libgomp.c-c++-common/refcount-1.c: New testcase.
* testsuite/libgomp.c-c++-common/struct-elem-1.c: New testcase.
* testsuite/libgomp.c-c++-common/struct-elem-2.c: New testcase.
* testsuite/libgomp.c-c++-common/struct-elem-3.c: New testcase.
* testsuite/libgomp.c-c++-common/struct-elem-4.c: New testcase.
* testsuite/libgomp.c-c++-common/struct-elem-5.c: New testcase.
