Continue filling out DetermineCopyInOutArgument(). Implemented IsExplicitShape(const Shape&)

Author: eugeneepshteyn

flang/include/flang/Evaluate/shape.h

@@ -35,6 +35,7 @@ using Shape = std::vector<MaybeExtentExpr>;
 
 bool IsImpliedShape(const Symbol &);
 bool IsExplicitShape(const Symbol &);
+bool IsExplicitShape(const Shape &);
 
 // Conversions between various representations of shapes.
 std::optional<ExtentExpr> AsExtentArrayExpr(const Shape &);

flang/lib/Evaluate/call.cpp

@@ -281,17 +281,43 @@ static void DetermineCopyInOutArgument(
   if (actual.isAlternateReturn()) {
     return;
   }
-  const auto *dummyObj =
-      std::get_if<characteristics::DummyDataObject>(&dummy.u);
+  const auto *dummyObj{
+      std::get_if<characteristics::DummyDataObject>(&dummy.u)};
   if (!dummyObj) {
     // Only DummyDataObject has the information we need
     return;
   }
+
+  bool dummyIsValue{
+      dummyObj->attrs.test(characteristics::DummyDataObject::Attr::Value)};
+  if (dummyIsValue) {
+    actual.SetMayNeedCopyIn();
+    return;
+  }
+
   // Check actual contiguity, unless dummy doesn't care
-  bool actualContiguous =
+  bool actualTreatAsContiguous{
       dummyObj->ignoreTKR.test(common::IgnoreTKR::Contiguous) ||
-      IsSimplyContiguous(actual, sc.foldingContext());
-  bool actualVectorSubscript = HasVectorSubscript(actual);
+      IsSimplyContiguous(actual, sc.foldingContext())};
+
+  bool actualHasVectorSubscript{HasVectorSubscript(actual)};
+  bool actualIsArray{actual.Rank() > 0};
+
+  bool dummyIsArray{dummyObj->type.Rank() > 0};
+  bool dummyIsExplicitShape{
+      dummyIsArray ? IsExplicitShape(*dummyObj->type.shape()) : false};
+  bool dummyIsAssumedSize{dummyObj->type.attrs().test(
+      characteristics::TypeAndShape::Attr::AssumedSize)};
+  bool dummyNeedsContiguity{dummyIsArray &&
+      (dummyIsExplicitShape || dummyIsAssumedSize ||
+      dummyObj->attrs.test(characteristics::DummyDataObject::Attr::Contiguous))};
+  if (!actualTreatAsContiguous && dummyNeedsContiguity) {
+    actual.SetMayNeedCopyIn();
+    if (!actualHasVectorSubscript) {
+      actual.SetMayNeedCopyOut();
+    }
+  }
+
 
   // TODO
 }

flang/lib/Evaluate/shape.cpp

@@ -47,6 +47,17 @@ bool IsExplicitShape(const Symbol &original) {
   }
 }
 
+bool IsExplicitShape(const Shape &shape) {
+  // If extent expression is present for all dimensions, then assume
+  // explicit shape.
+  for (const auto &dim : shape) {
+    if (!dim) {
+      return false;
+    }
+  }
+  return true;
+}
+
 Shape GetShapeHelper::ConstantShape(const Constant<ExtentType> &arrayConstant) {
   CHECK(arrayConstant.Rank() == 1);
   Shape result;