forked from OSchip/llvm-project
fe252f8ed6
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> |
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