[Mlir-commits] [mlir] [Flang][OpenMP][MLIR] Initial array section mapping MLIR -> LLVM-IR lowering utilising omp.bounds (PR #68689)

[Kiran Chandramohan]

================
@@ -2001,61 +2111,204 @@ static bool targetOpSupported(Operation &opInst) {
 }
 
 static void
-handleDeclareTargetMapVar(llvm::ArrayRef<Value> mapOperands,
+handleDeclareTargetMapVar(MapInfoData &mapData,
                           LLVM::ModuleTranslation &moduleTranslation,
                           llvm::IRBuilderBase &builder) {
-  for (const mlir::Value &mapOp : mapOperands) {
-    auto mapInfoOp =
-        mlir::dyn_cast<mlir::omp::MapInfoOp>(mapOp.getDefiningOp());
-    llvm::Value *mapOpValue =
-        moduleTranslation.lookupValue(mapInfoOp.getVarPtr());
-    if (auto *declareTarget = getRefPtrIfDeclareTarget(mapInfoOp.getVarPtr(),
-                                                       moduleTranslation)) {
-      // The user's iterator will get invalidated if we modify an element,
+  for (size_t i = 0; i < mapData.MapClause.size(); ++i) {
+    // In the case of declare target mapped variables, the basePointer is
+    // the reference pointer generated by the convertDeclareTargetAttr
+    // method. Whereas the kernelValue is the original variable, so for
+    // the device we must replace all uses of this original global variable
+    // (stored in kernelValue) with the reference pointer (stored in
+    // basePointer for declare target mapped variables), as for device the
+    // data is mapped into this reference pointer and should be loaded
+    // from it, the original variable is discarded. On host both exist and
+    // metadata is generated (elsewhere in the convertDeclareTargetAttr)
+    // function to link the two variables in the runtime and then both the
+    // reference pointer and the pointer are assigned in the kernel argument
+    // structure for the host.
+    if (mapData.IsDeclareTarget[i]) {
+      // The users iterator will get invalidated if we modify an element,
       // so we populate this vector of uses to alter each user on an individual
       // basis to emit its own load (rather than one load for all).
       llvm::SmallVector<llvm::User *> userVec;
-      for (llvm::User *user : mapOpValue->users())
+      for (llvm::User *user : mapData.OriginalValue[i]->users())
         userVec.push_back(user);
 
-      for (llvm::User *user : userVec) {
+      for (auto *user : userVec) {
----------------
kiranchandramohan wrote:

Nit: Was there a need for the type change here?

https://github.com/llvm/llvm-project/pull/68689