As mentioned in: https://gcc.gnu.org/ml/gcc-patches/2018-11/msg01773.html
I had a few more changes planned for the reference-counting implementation for OpenACC in libgomp. These are embodied in this patch series. The highlights are: - reference counts in the linked memory-mapping splay tree structure can be self-checked for consistency using optional (i.e. development-only) code. This survives a libgomp test run (with offloading to nvptx), so I'm reasonably confident it's good. - the "data_environ" field in the device descriptor -- a linear linked list containing a target memory descriptor for each "acc enter data" mapping -- has been removed. This brings OpenACC closer to the OpenMP implementation for non-lexically-scoped data mapping (GOMP_target_enter_exit_data), and is potentially a performance win if lots of data is mapped in this way. - the semantics of the "dynamic_refcount" field in the splay_tree_key structure have shifted slightly, so I've renamed the field. It now represents references that are excess to those represented by actual pointers in the linked splay tree/target-memory descriptor structure. That might have been the intention before in fact, but the implementation was inconsistent. I will apply to the og8 branch shortly. Julian Brown (2): [og8] Further OpenACC reference-counting improvements [og8] OpenACC reference count consistency checking libgomp/libgomp.h | 55 +++-- libgomp/oacc-async.c | 64 +++++ libgomp/oacc-host.c | 2 - libgomp/oacc-init.c | 6 +- libgomp/oacc-int.h | 5 + libgomp/oacc-mem.c | 206 ++++------------ libgomp/oacc-parallel.c | 160 +++++++----- libgomp/target.c | 262 ++++++++++++++++++-- .../libgomp.oacc-c-c++-common/deep-copy-7.c | 11 +- .../libgomp.oacc-c-c++-common/deep-copy-8.c | 1 + 10 files changed, 499 insertions(+), 273 deletions(-)
