[flang-commits] [flang] [flang] implement sizeof lowering for polymorphic entities (PR #84498)

[via flang-commits]

https://github.com/jeanPerier created https://github.com/llvm/llvm-project/pull/84498

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).

>From d0858c0c5429620fb79a27c0763807ae4153fca5 Mon Sep 17 00:00:00 2001
From: Jean Perier <jperier at nvidia.com>
Date: Fri, 8 Mar 2024 03:02:47 -0800
Subject: [PATCH] [flang] implement sizeof lowering for polymorphic entities

---
 .../flang/Optimizer/Builder/IntrinsicCall.h   |  1 +
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 18 +++++++++++++++
 flang/test/Lower/Intrinsics/sizeof.f90        | 23 +++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 flang/test/Lower/Intrinsics/sizeof.f90

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>