[PATCH] D152554: [OpenMP] Migrate deviice code privatization from Clang CodeGen to OMPIRBuilder

[Akash Banerjee via Phabricator via cfe-commits]

TIFitis added inline comments.


================
Comment at: clang/lib/CodeGen/CGStmtOpenMP.cpp:7170-7234
+    const llvm::Value *DevPtr = nullptr;
 
     // In order to identify the right initializer we need to match the
     // declaration used by the mapping logic. In some cases we may get
     // OMPCapturedExprDecl that refers to the original declaration.
-    const ValueDecl *MatchingVD = OrigVD;
-    if (const auto *OED = dyn_cast<OMPCapturedExprDecl>(MatchingVD)) {
+    if (const auto *OED = dyn_cast<OMPCapturedExprDecl>(OrigVD)) {
       // OMPCapturedExprDecl are used to privative fields of the current
----------------
Currently clang maintains a map between Clang::ValueDecl and corresponding address in Info.CaptureDeviceAddrMap.

Please see the EmitOMPUseDeviceAddrClause function just below this to see how it does so.

I would however like to get rid of this map as it allows us to then get rid of another map in the MapInfosTy and a clang specific callback for maintaining these maps..

This map is only used to retain the mapping between a ValueDecl inside a map clause to its corresponding llvm address.

The highlighted code here tries to retrieve this llvm address back from the ValueDecl without using the map, but as you can it is a very hacky way of doing so. But my intuition says that there must be a much simpler method of retrieving this address as Clang must be storing it in some way in order for it to generate code.

It would be great if someone with more experience in Clang codegen could help me achieve this. 

Also I am aware that I am probably doing a very poor job at explaining this. Please let me know if you have any questions or would like me to try and explain it with more clarity.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152554/new/

https://reviews.llvm.org/D152554