[flang][DRAFT] Copy-in/Copy-out determination

[eugeneepshteyn]

Plumbing/API for copy-in/copy-out work

[eugeneepshteyn]

Here go through the actual args and dummy args and determine copy-in and copy-out needs.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff HEAD~1 HEAD --extensions h,cpp -- flang/include/flang/Evaluate/call.h flang/lib/Evaluate/call.cpp

View the diff from clang-format here.

diff --git a/flang/lib/Evaluate/call.cpp b/flang/lib/Evaluate/call.cpp
index c558335c1..5a94071d9 100644
--- a/flang/lib/Evaluate/call.cpp
+++ b/flang/lib/Evaluate/call.cpp
@@ -254,8 +254,8 @@ void ProcedureRef::DetermineCopyInOut() {
   }
   // Get folding context of the call site owner
   FoldingContext &fc{proc_.GetSymbol()->owner().context().foldingContext()};
-  auto procInfo{characteristics::Procedure::Characterize(
-      proc_, fc, /*emitError=*/true)};
+  auto procInfo{
+      characteristics::Procedure::Characterize(proc_, fc, /*emitError=*/true)};
   if (!procInfo) {
     return;
   }

[klausler]

It might be cleaner to do the analysis at the time that the ProcedureRef is created by expression semantics rather than patching the IR later in lowering. It could then be used in Semantics/check-call.cpp for all of the errors and warnings that depend on copy-in/copy-out instead of the ad-hoc analysis currently done that relies on contiguity &c.