[llvm-branch-commits] [flang] [flang][OpenMP] Support tasks' implicit firstprivate DSA (PR #85989)

[Kiran Chandramohan via llvm-branch-commits]

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@@ -2012,34 +2012,87 @@ void OmpAttributeVisitor::Post(const parser::Name &name) {
         }
       }
     }
-    std::vector<Symbol *> defaultDSASymbols;
+
+    // Implicitly determined DSAs
+    // OMP 5.2 5.1.1 - Variables Referenced in a Construct
+    Symbol *lastDeclSymbol = nullptr;
+    std::optional<Symbol::Flag> prevDSA;
     for (int dirDepth{0}; dirDepth < (int)dirContext_.size(); ++dirDepth) {
       DirContext &dirContext = dirContext_[dirDepth];
-      bool hasDataSharingAttr{false};
+      std::optional<Symbol::Flag> dsa;
+
       for (auto symMap : dirContext.objectWithDSA) {
         // if the `symbol` already has a data-sharing attribute
         if (symMap.first->name() == name.symbol->name()) {
-          hasDataSharingAttr = true;
+          dsa = symMap.second;
           break;
         }
       }
-      if (hasDataSharingAttr) {
-        if (defaultDSASymbols.size())
-          symbol = &MakeAssocSymbol(symbol->name(), *defaultDSASymbols.back(),
+
+      // When handling each implicit rule, either a new private symbol is
+      // declared or the last declared symbol is used.
+      // In the latter case, it's necessary to insert a new symbol in the scope
+      // being processed, associated with the last declared symbol, to avoid
+      // "inheriting" the enclosing context's symbol and its flags.
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kiranchandramohan wrote:

Can you expand the `latter case`? On a first look it feels like we should be OK with just inheriting the enclosing context's symbol and its flags. Probably you have to say something like we have to create a new symbol to capture the fact that although we are using the last declared symbol its datasharing attribute could be different in this scope and give an example.

https://github.com/llvm/llvm-project/pull/85989