[flang-commits] [flang] [flang][OpenMP][MLIR] Basic support for delayed privatization code-gen (PR #81833)

[Leandro Lupori via flang-commits]

================
@@ -338,11 +335,95 @@ void DataSharingProcessor::defaultPrivatize() {
         !sym->GetUltimate().has<Fortran::semantics::NamelistDetails>() &&
         !symbolsInNestedRegions.contains(sym) &&
         !symbolsInParentRegions.contains(sym) &&
-        !privatizedSymbols.contains(sym)) {
+        !privatizedSymbols.contains(sym))
+      doPrivatize(sym);
+  }
+}
+
+void DataSharingProcessor::doPrivatize(const Fortran::semantics::Symbol *sym) {
+  if (!useDelayedPrivatization) {
+    cloneSymbol(sym);
+    copyFirstPrivateSymbol(sym);
+    return;
+  }
+
+  Fortran::lower::SymbolBox hsb = converter.lookupOneLevelUpSymbol(*sym);
+  assert(hsb && "Host symbol box not found");
+
+  mlir::Type symType = hsb.getAddr().getType();
+  mlir::Location symLoc = hsb.getAddr().getLoc();
+  std::string privatizerName = sym->name().ToString() + ".privatizer";
+  bool isFirstPrivate =
+      sym->test(Fortran::semantics::Symbol::Flag::OmpFirstPrivate);
+
+  mlir::omp::PrivateClauseOp privatizerOp = [&]() {
+    auto moduleOp = firOpBuilder.getModule();
+    auto uniquePrivatizerName = fir::getTypeAsString(
+        symType, converter.getKindMap(),
+        converter.mangleName(*sym) +
+            (isFirstPrivate ? "_firstprivate" : "_private"));
+
+    if (auto existingPrivatizer =
+            moduleOp.lookupSymbol<mlir::omp::PrivateClauseOp>(
+                uniquePrivatizerName))
+      return existingPrivatizer;
+
+    auto ip = firOpBuilder.saveInsertionPoint();
+    firOpBuilder.setInsertionPoint(&moduleOp.getBodyRegion().front(),
+                                   moduleOp.getBodyRegion().front().begin());
+    auto result = firOpBuilder.create<mlir::omp::PrivateClauseOp>(
+        symLoc, uniquePrivatizerName, symType,
+        isFirstPrivate ? mlir::omp::DataSharingClauseType ::FirstPrivate
+                       : mlir::omp::DataSharingClauseType::Private);
+
+    symTable->pushScope();
+
+    // Populate the `alloc` region.
+    {
+      mlir::Region &allocRegion = result.getAllocRegion();
+      mlir::Block *allocEntryBlock = firOpBuilder.createBlock(
+          &allocRegion, /*insertPt=*/{}, symType, symLoc);
+
+      firOpBuilder.setInsertionPointToEnd(allocEntryBlock);
+      symTable->addSymbol(*sym, allocRegion.getArgument(0));
+      symTable->pushScope();
       cloneSymbol(sym);
-      copyFirstPrivateSymbol(sym);
+      firOpBuilder.create<mlir::omp::YieldOp>(
+          hsb.getAddr().getLoc(),
+          symTable->shallowLookupSymbol(*sym).getAddr());
+      symTable->popScope();
     }
-  }
+
+    // Poplate the `copy` region if this is a `firstprivate`.
----------------
luporl wrote:

```suggestion
    // Populate the `copy` region if this is a `firstprivate`.
```

https://github.com/llvm/llvm-project/pull/81833