[flang] Lower volatile class types (llvm#138607)

So far, only boxes and references have had their volatile attribute set
during lowering. This patch enables the volatility of classes to be
properly represented in the ir, same as box and ref.

For simple cases, not much needs to change in the codegen or conversion
patterns because the prior work on volatile refs/boxes propagates
volatility already. I am running further testing with the strict
verification enabled to find remaining cases of incorrect/missing
volatile propagation.

Author: ashermancinelli

flang/lib/Lower/ConvertExprToHLFIR.cpp

@@ -205,17 +205,8 @@ class HlfirDesignatorBuilder {
       partInfo.resultShape =
           hlfir::genShape(getLoc(), getBuilder(), *partInfo.base);
 
-    // Dynamic type of polymorphic base must be kept if the designator is
-    // polymorphic.
-    if (isPolymorphic(designatorNode))
-      return fir::ClassType::get(resultValueType);
-    // Character scalar with dynamic length needs a fir.boxchar to hold the
-    // designator length.
-    auto charType = mlir::dyn_cast<fir::CharacterType>(resultValueType);
-    if (charType && charType.hasDynamicLen())
-      return fir::BoxCharType::get(charType.getContext(), charType.getFKind());
-
-    // When volatile is enabled, enable volatility on the designatory type.
+    // Enable volatility on the designatory type if it has the VOLATILE
+    // attribute or if the base is volatile.
     bool isVolatile = false;
 
     // Check if this should be a volatile reference
@@ -236,6 +227,17 @@ class HlfirDesignatorBuilder {
         isVolatile = true;
     }
 
+    // Dynamic type of polymorphic base must be kept if the designator is
+    // polymorphic.
+    if (isPolymorphic(designatorNode))
+      return fir::ClassType::get(resultValueType, isVolatile);
+
+    // Character scalar with dynamic length needs a fir.boxchar to hold the
+    // designator length.
+    auto charType = mlir::dyn_cast<fir::CharacterType>(resultValueType);
+    if (charType && charType.hasDynamicLen())
+      return fir::BoxCharType::get(charType.getContext(), charType.getFKind());
+
     // Check if the base type is volatile
     if (partInfo.base.has_value()) {
       mlir::Type baseType = partInfo.base.value().getType();

flang/test/Lower/volatile-derived-type-pointer.f90

@@ -0,0 +1,43 @@
+! RUN: bbc %s -o - --strict-fir-volatile-verifier | FileCheck %s
+
+! Ensure that assignments between volatile classes/derived type pointer/targets
+! lower to the correct hlfir declare/designate operations.
+
+module m
+  type :: dt
+    character :: c0="!"
+    integer   :: i=0
+    character :: c1="!"
+  end type
+  end module
+  program dataptrvolatile
+  use m
+  implicit none
+  type(dt),  volatile , target  :: arr(100, 100), arr1(10000), t(100,100)
+  class(dt), volatile , pointer :: ptr(:, :)
+  integer             :: i, j
+  do i =1, 100
+  do j =i, 100
+    arr(i:, j:) = dt(i=-i)
+    ptr(i:, j:) => arr(i:, j:)
+    t(i:, j:) = ptr(i:, j:)
+  end do
+  end do
+end
+
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}}(%{{.+}}) {fortran_attrs = #fir.var_attrs<target, volatile>, uniq_name = "_QFEarr"} : (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, !fir.shape<2>) -> (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, !fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>)
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}}(%{{.+}}) {fortran_attrs = #fir.var_attrs<target, volatile>, uniq_name = "_QFEarr1"} : (!fir.ref<!fir.array<10000x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, !fir.shape<1>) -> (!fir.ref<!fir.array<10000x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, !fir.ref<!fir.array<10000x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>)
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}} {uniq_name = "_QFEi"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}} {uniq_name = "_QFEj"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}} {fortran_attrs = #fir.var_attrs<pointer, volatile>, uniq_name = "_QFEptr"} : (!fir.ref<!fir.class<!fir.ptr<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>>, volatile>, volatile>) -> (!fir.ref<!fir.class<!fir.ptr<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>>, volatile>, volatile>, !fir.ref<!fir.class<!fir.ptr<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>>, volatile>, volatile>)
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}}(%{{.+}}) {fortran_attrs = #fir.var_attrs<target, volatile>, uniq_name = "_QFEt"} : (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, !fir.shape<2>) -> (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, !fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>)
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}} {uniq_name = "ctor.temp"} : (!fir.ref<!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>) -> (!fir.ref<!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, !fir.ref<!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>)
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}}#0{"c0"}   typeparams %{{.+}} : (!fir.ref<!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, index) -> !fir.ref<!fir.char<1>>
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}} typeparams %{{.+}} {fortran_attrs = #fir.var_attrs<parameter>, uniq_name = "_QQclX21"} : (!fir.ref<!fir.char<1>>, index) -> (!fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>)
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}}#0{"i"}   : (!fir.ref<!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>) -> !fir.ref<i32>
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}}#0{"c1"}   typeparams %{{.+}} : (!fir.ref<!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, index) -> !fir.ref<!fir.char<1>>
+! CHECK:           %{{.+}}:2 = hlfir.declare %{{.+}} typeparams %{{.+}} {fortran_attrs = #fir.var_attrs<parameter>, uniq_name = "_QQclX21"} : (!fir.ref<!fir.char<1>>, index) -> (!fir.ref<!fir.char<1>>, !fir.ref<!fir.char<1>>)
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}}#0 (%{{.+}}:%{{.+}}:%{{.+}}, %{{.+}}:%{{.+}}:%{{.+}})  shape %{{.+}} : (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, index, index, index, index, index, index, !fir.shape<2>) -> !fir.box<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}}#0 (%{{.+}}:%{{.+}}:%{{.+}}, %{{.+}}:%{{.+}}:%{{.+}})  shape %{{.+}} : (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, index, index, index, index, index, index, !fir.shape<2>) -> !fir.box<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}} (%{{.+}}:%{{.+}}:%{{.+}}, %{{.+}}:%{{.+}}:%{{.+}})  shape %{{.+}} : (!fir.class<!fir.ptr<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>>, volatile>, index, index, index, index, index, index, !fir.shape<2>) -> !fir.class<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>
+! CHECK:           %{{.+}} = hlfir.designate %{{.+}}#0 (%{{.+}}:%{{.+}}:%{{.+}}, %{{.+}}:%{{.+}}:%{{.+}})  shape %{{.+}} : (!fir.ref<!fir.array<100x100x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>, index, index, index, index, index, index, !fir.shape<2>) -> !fir.box<!fir.array<?x?x!fir.type<_QMmTdt{c0:!fir.char<1>,i:i32,c1:!fir.char<1>}>>, volatile>