WiP: New OpenACC features for GPUFORT runtime

[domcharrier]

FEATURES:

• Initial support for acc declare

• OpenACC (gpufort runtime)

  • offloaded loops:
    • add default clause handling
    • default strategy is present_or_copy if neither default(none) nor default(present) s specified.
  • Initial support for acc declare (module/subroutine/function/program variables, fixed-size, allocatable, pointer)

• Add interoperable GPUFORT array datatype (up to 7 dimensions; autogenerated):

  • Manage host and device pointer pair (can be null)
    • Either wrap exisiting pointers or
    • Allocate (pinned) host memory requested
    • Allocate device memory if requested
  • Provide H2D, D2H copy operations
  • Encode bounds and sizes of an Fortran array
  • Can be configured to perform H2D, D2H copy operations at init/destruction
  • In C++, equipped with operator()(int i1, int i2, ...) to support Fortran style array indexing in C++ code. No index macros.

• Will be used by GPUFORT to construct interoperable derived types from non-interoperable device types. This will allow AoS syntax such as: domains(5).cells(i).coord_x in GPUFORT C++ code, which is analogous to the Fortran equivalent: domain(5)%cells(i)%coord_x.

BUGFIXES:

• Fix crash when encountering top-level subroutines/functions.