[PATCH] D133539: [OpenMP] Replace OpenMP register requires constructor with a global array

[Joseph Huber via Phabricator via llvm-commits]

jhuber6 created this revision.
jhuber6 added reviewers: jdoerfert, JonChesterfield, tianshilei1992, ABataev, ronlieb, doru1004, RaviNarayanaswamy.
Herald added subscribers: guansong, yaxunl.
Herald added a project: All.
jhuber6 requested review of this revision.
Herald added subscribers: llvm-commits, cfe-commits, sstefan1.
Herald added projects: clang, LLVM.

Currently, every module containing OpenMP offloading code uses a global
constructor to register its flags from the `omp requires` clause. This
is not ideal as it creates several entry points into `libomptarget` that
requires the runtime to be initialized first. This makes it difficult
for us to transition to a scheme where the lifetime of `libomptarget` is
explicitly manages by the uses of the `__tgt_[un]register_lib` calls.

Instead, this patch changes the method to create global values similar
to how offloading entries are registered. The linker will create a
`__start/__stop` pointer for these values which we can then iterate
through in the runtime. This requires widening the `__tgt_bin_desc`
struct which is an ABI break as old programs  will attempt to read
invalid memory and the old interface will be removed. This will be
acceptable if we go through with the plans in D133277 <https://reviews.llvm.org/D133277> and remove the
backwards compatibility in `libomptarget`.

If we do not wish to add a new field to `__tgt_bin_desc` we could
instead add it to the exiting `__tgt_offload_entry` and filter it out.
But this would require using the `Size` field or something similar to
hold the value and updating all the plugins.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133539

Files:
  clang/lib/CodeGen/CGOpenMPRuntime.cpp
  clang/lib/CodeGen/CGOpenMPRuntime.h
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/test/Driver/linker-wrapper-image.c
  clang/test/OpenMP/distribute_codegen.cpp
  clang/test/OpenMP/distribute_firstprivate_codegen.cpp
  clang/test/OpenMP/distribute_lastprivate_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_firstprivate_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_if_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_lastprivate_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_num_threads_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_private_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_proc_bind_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_firstprivate_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_if_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_lastprivate_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_num_threads_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_private_codegen.cpp
  clang/test/OpenMP/distribute_parallel_for_simd_proc_bind_codegen.cpp
  clang/test/OpenMP/distribute_private_codegen.cpp
  clang/test/OpenMP/distribute_simd_codegen.cpp
  clang/test/OpenMP/distribute_simd_firstprivate_codegen.cpp
  clang/test/OpenMP/distribute_simd_lastprivate_codegen.cpp
  clang/test/OpenMP/distribute_simd_private_codegen.cpp
  clang/test/OpenMP/distribute_simd_reduction_codegen.cpp
  clang/test/OpenMP/openmp_offload_registration.cpp
  clang/test/OpenMP/reduction_implicit_map.cpp
  clang/test/OpenMP/target_codegen.cpp
  clang/test/OpenMP/target_codegen_global_capture.cpp
  clang/test/OpenMP/target_codegen_registration.cpp
  clang/test/OpenMP/target_depend_codegen.cpp
  clang/test/OpenMP/target_map_codegen_03.cpp
  clang/test/OpenMP/target_offload_mandatory_codegen.cpp
  clang/test/OpenMP/target_parallel_codegen.cpp
  clang/test/OpenMP/target_parallel_codegen_registration.cpp
  clang/test/OpenMP/target_parallel_depend_codegen.cpp
  clang/test/OpenMP/target_parallel_for_codegen.cpp
  clang/test/OpenMP/target_parallel_for_codegen_registration.cpp
  clang/test/OpenMP/target_parallel_for_depend_codegen.cpp
  clang/test/OpenMP/target_parallel_for_simd_codegen.cpp
  clang/test/OpenMP/target_parallel_for_simd_codegen_registration.cpp
  clang/test/OpenMP/target_parallel_for_simd_depend_codegen.cpp
  clang/test/OpenMP/target_parallel_if_codegen.cpp
  clang/test/OpenMP/target_parallel_num_threads_codegen.cpp
  clang/test/OpenMP/target_simd_codegen.cpp
  clang/test/OpenMP/target_simd_codegen_registration.cpp
  clang/test/OpenMP/target_simd_depend_codegen.cpp
  clang/test/OpenMP/target_teams_codegen.cpp
  clang/test/OpenMP/target_teams_codegen_registration.cpp
  clang/test/OpenMP/target_teams_depend_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_codegen_registration.cpp
  clang/test/OpenMP/target_teams_distribute_collapse_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_depend_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_dist_schedule_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_firstprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_lastprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_collapse_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_depend_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_dist_schedule_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_firstprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_if_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_lastprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_private_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_proc_bind_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_reduction_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_schedule_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_codegen_registration.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_collapse_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_depend_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_dist_schedule_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_firstprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_if_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_lastprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_private_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_proc_bind_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_reduction_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_parallel_for_simd_schedule_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_private_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_reduction_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_codegen_registration.cpp
  clang/test/OpenMP/target_teams_distribute_simd_collapse_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_depend_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_dist_schedule_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_firstprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_lastprivate_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_private_codegen.cpp
  clang/test/OpenMP/target_teams_distribute_simd_reduction_codegen.cpp
  clang/test/OpenMP/target_teams_map_codegen.cpp
  clang/test/OpenMP/target_teams_num_teams_codegen.cpp
  clang/test/OpenMP/target_teams_thread_limit_codegen.cpp
  clang/test/OpenMP/teams_codegen.cpp
  clang/test/OpenMP/teams_distribute_codegen.cpp
  clang/test/OpenMP/teams_distribute_collapse_codegen.cpp
  clang/test/OpenMP/teams_distribute_dist_schedule_codegen.cpp
  clang/test/OpenMP/teams_distribute_firstprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_lastprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_collapse_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_copyin_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_dist_schedule_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_firstprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_if_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_lastprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_num_threads_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_private_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_proc_bind_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_reduction_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_schedule_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_collapse_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_dist_schedule_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_firstprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_if_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_lastprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_num_threads_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_private_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_proc_bind_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_reduction_codegen.cpp
  clang/test/OpenMP/teams_distribute_parallel_for_simd_schedule_codegen.cpp
  clang/test/OpenMP/teams_distribute_private_codegen.cpp
  clang/test/OpenMP/teams_distribute_reduction_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_collapse_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_dist_schedule_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_firstprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_lastprivate_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_private_codegen.cpp
  clang/test/OpenMP/teams_distribute_simd_reduction_codegen.cpp
  clang/test/OpenMP/teams_firstprivate_codegen.cpp
  clang/test/OpenMP/teams_private_codegen.cpp
  clang/tools/clang-linker-wrapper/OffloadWrapper.cpp
  llvm/include/llvm/Frontend/OpenMP/OMPKinds.def