[Openmp-commits] [PATCH] D97883: [libomptarget] Add allocator support for target memory

[George Rokos via Phabricator via Openmp-commits]

grokos created this revision.
grokos added reviewers: hbae, RaviNarayanaswamy, jdoerfert, JonChesterfield.
grokos added a project: OpenMP.
grokos requested review of this revision.
Herald added a subscriber: sstefan1.

This patch adds the infrastructure for allocator support for target memory. Three allocators are introduced for device, host and shared memory. The corresponding API functions have the `llvm_` prefix temporarily, until they become part of the OpenMP standard:

`llvm_omp_target_alloc_device(size_t size, int device_num);`

- Returns memory owned by device.
- Memory is only accessible by device.

`llvm_omp_target_alloc_host(size_t size, int device_num);`

- Returns non-migratable memory owned by host.
- Memory is accessible by host and device(s).

`llvm_omp_target_alloc_shared(size_t size, int device_num);`

- Returns migratable memory owned by host and device.
- Memory is accessible by host and device.

The corresponding host OpenMP runtime patch is D96669 <https://reviews.llvm.org/D96669>.

Ultimately, libomptarget needs support from each plugin to allocate memory using the desired method. A new plugin function `__tgt_rtl_data_alloc_explicit` (optional) is introduced which is called by the base library to allocate memory appropriately. The patch provides a trivial sample implementation using the `generic-elf-64` plugin.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D97883

Files:
  openmp/libomptarget/include/omptarget.h
  openmp/libomptarget/include/omptargetplugin.h
  openmp/libomptarget/plugins/exports
  openmp/libomptarget/plugins/generic-elf-64bit/src/rtl.cpp
  openmp/libomptarget/src/api.cpp
  openmp/libomptarget/src/device.cpp
  openmp/libomptarget/src/device.h
  openmp/libomptarget/src/exports
  openmp/libomptarget/src/rtl.cpp
  openmp/libomptarget/src/rtl.h

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