[flang] implement sizeof lowering for polymorphic entities

[jeanPerier]

For non polymorphic entities, semantics knows the type size and rewrite sizeof to "cst element size" * size(x).

Lowering has to deal with the polymorphic case where the type size must be retrieved from the descriptor (note that the lowering implementation would work with any entity, polymorphic on not, it is just not used for the non polymorphic cases).

[llvmbot]

@llvm/pr-subscribers-flang-fir-hlfir

Author: None (jeanPerier)

Changes

For non polymorphic entities, semantics knows the type size and rewrite sizeof to "cst element size" * size(x).

Lowering has to deal with the polymorphic case where the type size must be retrieved from the descriptor (note that the lowering implementation would work with any entity, polymorphic on not, it is just not used for the non polymorphic cases).

---

Full diff: https://github.com/llvm/llvm-project/pull/84498.diff

3 Files Affected:

• (modified) flang/include/flang/Optimizer/Builder/IntrinsicCall.h (+1)
• (modified) flang/lib/Optimizer/Builder/IntrinsicCall.cpp (+18)
• (added) flang/test/Lower/Intrinsics/sizeof.f90 (+23)

diff --git a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
index 7cb99d61a686ed..ca15b4bc34b29e 100644
--- a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
+++ b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
@@ -338,6 +338,7 @@ struct IntrinsicLibrary {
   mlir::Value genSign(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genSind(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genSize(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
+  fir::ExtendedValue genSizeOf(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   mlir::Value genSpacing(mlir::Type resultType,
                          llvm::ArrayRef<mlir::Value> args);
   fir::ExtendedValue genSpread(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 2f7ace658e4752..ca5ab6fcea342a 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -567,6 +567,10 @@ static constexpr IntrinsicHandler handlers[]{
        {"dim", asAddr, handleDynamicOptional},
        {"kind", asValue}}},
      /*isElemental=*/false},
+    {"sizeof",
+     &I::genSizeOf,
+     {{{"a", asBox}}},
+     /*isElemental=*/false},
     {"sleep", &I::genSleep, {{{"seconds", asValue}}}, /*isElemental=*/false},
     {"spacing", &I::genSpacing},
     {"spread",
@@ -5946,6 +5950,20 @@ IntrinsicLibrary::genSize(mlir::Type resultType,
       .getResults()[0];
 }
 
+// SIZEOF
+fir::ExtendedValue
+IntrinsicLibrary::genSizeOf(mlir::Type resultType,
+                            llvm::ArrayRef<fir::ExtendedValue> args) {
+  assert(args.size() == 1);
+  mlir::Value box = fir::getBase(args[0]);
+  mlir::Value eleSize = builder.create<fir::BoxEleSizeOp>(loc, resultType, box);
+  if (!fir::isArray(args[0]))
+    return eleSize;
+  mlir::Value arraySize = builder.createConvert(
+      loc, resultType, fir::runtime::genSize(builder, loc, box));
+  return builder.create<mlir::arith::MulIOp>(loc, eleSize, arraySize);
+}
+
 // TAND
 mlir::Value IntrinsicLibrary::genTand(mlir::Type resultType,
                                       llvm::ArrayRef<mlir::Value> args) {
diff --git a/flang/test/Lower/Intrinsics/sizeof.f90 b/flang/test/Lower/Intrinsics/sizeof.f90
new file mode 100644
index 00000000000000..959ca1692b5144
--- /dev/null
+++ b/flang/test/Lower/Intrinsics/sizeof.f90
@@ -0,0 +1,23 @@
+! Test SIZEOF lowering for polymorphic entities.
+! RUN: bbc -emit-hlfir --polymorphic-type -o - %s | FileCheck %s
+
+integer(8) function test1(x)
+  class(*) :: x
+  test1 = sizeof(x)
+end function
+! CHECK-LABEL:   func.func @_QPtest1(
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %{{.*}} {uniq_name = "_QFtest1Ex"} : (!fir.class<none>) -> (!fir.class<none>, !fir.class<none>)
+! CHECK:           %[[VAL_4:.*]] = fir.box_elesize %[[VAL_3]]#1 : (!fir.class<none>) -> i64
+! CHECK:           hlfir.assign %[[VAL_4]] to %{{.*}} : i64, !fir.ref<i64>
+
+integer(8) function test2(x)
+  class(*) :: x(:, :)
+  test2 = sizeof(x)
+end function
+! CHECK-LABEL:   func.func @_QPtest2(
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %{{.*}} {uniq_name = "_QFtest2Ex"} : (!fir.class<!fir.array<?x?xnone>>) -> (!fir.class<!fir.array<?x?xnone>>, !fir.class<!fir.array<?x?xnone>>)
+! CHECK:           %[[VAL_4:.*]] = fir.box_elesize %[[VAL_3]]#1 : (!fir.class<!fir.array<?x?xnone>>) -> i64
+! CHECK:           %[[VAL_7:.*]] = fir.convert %[[VAL_3]]#1 : (!fir.class<!fir.array<?x?xnone>>) -> !fir.box<none>
+! CHECK:           %[[VAL_9:.*]] = fir.call @_FortranASize(%[[VAL_7]], %{{.*}}, %{{.*}}) fastmath<contract> : (!fir.box<none>, !fir.ref<i8>, i32) -> i64
+! CHECK:           %[[VAL_10:.*]] = arith.muli %[[VAL_4]], %[[VAL_9]] : i64
+! CHECK:           hlfir.assign %[[VAL_10]] to %{{.*}} : i64, !fir.ref<i64>

[tblah]

Looks good to me, thanks!

[vzakhari]

Thank you, Jean!