[flang-commits] [flang] [mlir] [flang][OpenMP] Lower allocator-backed storage for allocate clauses (PR #211621)

[Tom Eccles via flang-commits]

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@@ -3498,6 +3285,59 @@ genParallelOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
   assert((!enableDelayedPrivatization || dsp) &&
          "expected valid DataSharingProcessor");
 
+  if (!clauseOps.allocateVars.empty()) {
+    llvm::DenseMap<const semantics::Symbol *, int64_t> privateSlots;
+    for (auto [index, object] : llvm::enumerate(args.priv.objects)) {
+      const semantics::Symbol *symbol = object.sym();
+      if (!symbol)
+        TODO(loc, "ALLOCATE clause private item without a semantic symbol");
+      const semantics::Symbol *ultimate = &symbol->GetUltimate();
+      if (!privateSlots.try_emplace(ultimate, index).second)
+        TODO(loc, "ALLOCATE clause item has multiple private storage slots");
+    }
+
+    llvm::DenseSet<const semantics::Symbol *> allocateSymbols;
+    for (const Clause &clause : item->clauses) {
+      if (clause.id != llvm::omp::Clause::OMPC_allocate)
+        continue;
+      const auto &allocate = std::get<clause::Allocate>(clause.u);
+      const auto &objects = std::get<ObjectList>(allocate.t);
+      for (const Object &object : objects) {
+        const semantics::Symbol *symbol = object.sym();
+        if (!symbol)
+          TODO(loc, "ALLOCATE clause item without a semantic symbol");
+        const semantics::Symbol *ultimate = &symbol->GetUltimate();
+        if (!allocateSymbols.insert(ultimate).second)
+          TODO(loc, "ALLOCATE clause item appears more than once");
+
+        auto privateSlot = privateSlots.find(ultimate);
+        if (privateSlot == privateSlots.end())
+          TODO(loc, "ALLOCATE clause item has no private storage slot");
+
+        auto type = evaluate::DynamicType::From(*ultimate);
+        bool supportedDataSharing =
+            symbol->test(semantics::Symbol::Flag::OmpPrivate) ||
+            symbol->test(semantics::Symbol::Flag::OmpFirstPrivate);
+        bool supportedType =
+            ultimate->Rank() == 0 &&
+            !semantics::IsAllocatableOrPointer(*ultimate) && type &&
+            type->category() != common::TypeCategory::Derived &&
+            !type->RequiresDescriptor() &&
+            !type->HasDeferredOrAssumedTypeParameter();
+        if (!supportedDataSharing || !supportedType)
+          TODO(loc,
+               "ALLOCATE clause currently supports only fixed-size intrinsic "
+               "scalar PRIVATE or FIRSTPRIVATE items");
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tblah wrote:

This looks like a correct usage of TODO

https://github.com/llvm/llvm-project/pull/211621