In FIR, we want to wrap function pointers in a special box known as a
boxproc value. Fortran has a limited form of dynamic scoping
[https://tinyurl.com/2p8v2hw7] between "host procedures" and "internal
procedures". There are a number of implementations possible.
Boxproc typed values abstract away the implementation details of when a
function pointer can be passed directly (as a raw address) and when a
function pointer has to account for the presence of a dynamic scope.
When lowering Fortran syntax to FIR, all function pointers are emboxed
as boxproc values.
When creating LLVM IR, we must strip away the abstraction and produce
low-level LLVM "assembly" code. This patch implements that
transformation as converting the boxproc values to either raw function
pointers or executable trampolines on the stack as needed. The
trampoline then captures the dynamic scope context within an executable
thunk that can be passed instead of the function's raw address.
Some extra handling is required for Fortran functions that return a
character value to deal with LEN values here.
Some of the code in Bridge.cpp and ConvertExpr.cpp and be re-arranged to
faciliate the upstreaming effort.
This patch is part of the upstreaming effort from fir-dev branch.
Reviewed By: jeanPerier, PeteSteinfeld
Differential Revision: https://reviews.llvm.org/D122223
Co-authored-by: mleair <leairmark@gmail.com>
Co-authored-by: Jean Perier <jperier@nvidia.com>
Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: V Donaldson <vdonaldson@nvidia.com>
Co-authored-by: Kiran Chandramohan <kiran.chandramohan@arm.com>
This patch adds couple of tests for allocatable
on the callee side. Lowering for some missing underlying features
is added as well.
This patch is part of the upstreaming effort from fir-dev branch.
Depends on D120744
Reviewed By: PeteSteinfeld, schweitz
Differential Revision: https://reviews.llvm.org/D120746
Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: Jean Perier <jperier@nvidia.com>
Co-authored-by: V Donaldson <vdonaldson@nvidia.com>
Valentin Clement