[flang-commits] [flang] [Flang] Implement LOWER argument for C_F_POINTER (PR #149870)
Michael Klemm via flang-commits
flang-commits at lists.llvm.org
Mon Jul 21 11:53:52 PDT 2025
https://github.com/mjklemm created https://github.com/llvm/llvm-project/pull/149870
This PR resolves issue #147819 and adds support for the F2023 extension of the `LOWER=` argument for `C_F_POINTER`.
>From aaa6fbb0429fd09b9fb250136bac832966bbcb08 Mon Sep 17 00:00:00 2001
From: Michael Klemm <michael.klemm at amd.com>
Date: Mon, 21 Jul 2025 15:59:17 +0200
Subject: [PATCH 1/3] [Flang] Implement LOWER argument for C_F_POINTER
This PR adds support for the optional LOWER argument for C_F_POINTER
(Fortran 2023, 18.2.3.3)
---
flang/docs/F202X.md | 1 -
flang/lib/Evaluate/intrinsics.cpp | 44 +++++++++++++++++--
flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 26 +++++++++--
3 files changed, 62 insertions(+), 9 deletions(-)
diff --git a/flang/docs/F202X.md b/flang/docs/F202X.md
index 67ea7fd97449a..7504561a64aa6 100644
--- a/flang/docs/F202X.md
+++ b/flang/docs/F202X.md
@@ -268,7 +268,6 @@ Addressing some issues and omissions in intrinsic modules:
* LOGICAL8/16/32/64 and REAL16
* IEEE module facilities upgraded to match latest IEEE FP standard
* C_F_STRPOINTER, F_C_STRING for NUL-terminated strings
- * C_F_POINTER(LOWER=)
#### Intrinsic Procedure Extensions
diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index 9957010684d48..c48dea4b54b3a 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -3073,10 +3073,11 @@ IntrinsicProcTable::Implementation::HandleC_F_Pointer(
ActualArguments &arguments, FoldingContext &context) const {
characteristics::Procedure::Attrs attrs;
attrs.set(characteristics::Procedure::Attr::Subroutine);
- static const char *const keywords[]{"cptr", "fptr", "shape", nullptr};
+ static const char *const keywords[]{
+ "cptr", "fptr", "shape", "lower", nullptr};
characteristics::DummyArguments dummies;
- if (CheckAndRearrangeArguments(arguments, context.messages(), keywords, 1)) {
- CHECK(arguments.size() == 3);
+ if (CheckAndRearrangeArguments(arguments, context.messages(), keywords, 2)) {
+ CHECK(arguments.size() == 4);
if (const auto *expr{arguments[0].value().UnwrapExpr()}) {
// General semantic checks will catch an actual argument that's not
// scalar.
@@ -3169,11 +3170,30 @@ IntrinsicProcTable::Implementation::HandleC_F_Pointer(
}
}
}
+ if (arguments[3] && fptrRank == 0) {
+ context.messages().Say(arguments[3]->sourceLocation(),
+ "LOWER= argument to C_F_POINTER() may not appear when FPTR= is scalar"_err_en_US);
+ } else if (arguments[3]) {
+ if (const auto *argExpr{arguments[3].value().UnwrapExpr()}) {
+ if (argExpr->Rank() > 1) {
+ context.messages().Say(arguments[3]->sourceLocation(),
+ "LOWER= argument to C_F_POINTER() must be a rank-one array."_err_en_US);
+ } else if (argExpr->Rank() == 1) {
+ if (auto constShape{GetConstantShape(context, *argExpr)}) {
+ if (constShape->At(ConstantSubscripts{1}).ToInt64() != fptrRank) {
+ context.messages().Say(arguments[3]->sourceLocation(),
+ "LOWER= argument to C_F_POINTER() must have size equal to the rank of FPTR="_err_en_US);
+ }
+ }
+ }
+ }
+ }
}
}
if (dummies.size() == 2) {
+ // Handle SHAPE
DynamicType shapeType{TypeCategory::Integer, defaults_.sizeIntegerKind()};
- if (arguments[2]) {
+ if (arguments.size() >=3 && arguments[2]) {
if (auto type{arguments[2]->GetType()}) {
if (type->category() == TypeCategory::Integer) {
shapeType = *type;
@@ -3185,6 +3205,22 @@ IntrinsicProcTable::Implementation::HandleC_F_Pointer(
shape.intent = common::Intent::In;
shape.attrs.set(characteristics::DummyDataObject::Attr::Optional);
dummies.emplace_back("shape"s, std::move(shape));
+
+ // Handle LOWER
+ DynamicType lowerType{TypeCategory::Integer, defaults_.sizeIntegerKind()};
+ if (arguments.size() >= 4 && arguments[3]) {
+ if (auto type{arguments[3]->GetType()}) {
+ if (type->category() == TypeCategory::Integer) {
+ lowerType = *type;
+ }
+ }
+ }
+ characteristics::DummyDataObject lower{
+ characteristics::TypeAndShape{lowerType, 1}};
+ lower.intent = common::Intent::In;
+ lower.attrs.set(characteristics::DummyDataObject::Attr::Optional);
+ dummies.emplace_back("lower"s, std::move(lower));
+
return SpecificCall{
SpecificIntrinsic{"__builtin_c_f_pointer"s,
characteristics::Procedure{std::move(dummies), attrs}},
diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index d77a656158a37..a99c4cb112c21 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -369,7 +369,8 @@ static constexpr IntrinsicHandler handlers[]{
&I::genCFPointer,
{{{"cptr", asValue},
{"fptr", asInquired},
- {"shape", asAddr, handleDynamicOptional}}},
+ {"shape", asAddr, handleDynamicOptional},
+ {"lower", asAddr, handleDynamicOptional}}},
/*isElemental=*/false},
{"c_f_procpointer",
&I::genCFProcPointer,
@@ -3403,7 +3404,7 @@ IntrinsicLibrary::genCDevLoc(mlir::Type resultType,
// C_F_POINTER
void IntrinsicLibrary::genCFPointer(llvm::ArrayRef<fir::ExtendedValue> args) {
- assert(args.size() == 3);
+ assert(args.size() == 4);
// Handle CPTR argument
// Get the value of the C address or the result of a reference to C_LOC.
mlir::Value cPtr = fir::getBase(args[0]);
@@ -3418,9 +3419,12 @@ void IntrinsicLibrary::genCFPointer(llvm::ArrayRef<fir::ExtendedValue> args) {
mlir::Value addr =
builder.createConvert(loc, fPtr->getMemTy(), cPtrAddrVal);
mlir::SmallVector<mlir::Value> extents;
+ mlir::SmallVector<mlir::Value> lbounds;
if (box.hasRank()) {
assert(isStaticallyPresent(args[2]) &&
"FPTR argument must be an array if SHAPE argument exists");
+
+ // Handle and unpack SHAPE argument
mlir::Value shape = fir::getBase(args[2]);
int arrayRank = box.rank();
mlir::Type shapeElementType =
@@ -3433,17 +3437,31 @@ void IntrinsicLibrary::genCFPointer(llvm::ArrayRef<fir::ExtendedValue> args) {
mlir::Value load = builder.create<fir::LoadOp>(loc, var);
extents.push_back(builder.createConvert(loc, idxType, load));
}
+
+ // Handle and unpack LOWER argument if present
+ if (isStaticallyPresent(args[3])) {
+ mlir::Value lower = fir::getBase(args[3]);
+ mlir::Type lowerElementType =
+ fir::unwrapSequenceType(fir::unwrapPassByRefType(lower.getType()));
+ for (int i = 0; i < arrayRank; ++i) {
+ mlir::Value index = builder.createIntegerConstant(loc, idxType, i);
+ mlir::Value var = builder.create<fir::CoordinateOp>(
+ loc, builder.getRefType(lowerElementType), lower, index);
+ mlir::Value load = builder.create<fir::LoadOp>(loc, var);
+ lbounds.push_back(builder.createConvert(loc, idxType, load));
+ }
+ }
}
if (box.isCharacter()) {
mlir::Value len = box.nonDeferredLenParams()[0];
if (box.hasRank())
- return fir::CharArrayBoxValue{addr, len, extents};
+ return fir::CharArrayBoxValue{addr, len, extents, lbounds};
return fir::CharBoxValue{addr, len};
}
if (box.isDerivedWithLenParameters())
TODO(loc, "get length parameters of derived type");
if (box.hasRank())
- return fir::ArrayBoxValue{addr, extents};
+ return fir::ArrayBoxValue{addr, extents, lbounds};
return addr;
};
>From 3e5f80c749997a49583c6fd40cd0d46fb3313b67 Mon Sep 17 00:00:00 2001
From: Michael Klemm <michael.klemm at amd.com>
Date: Mon, 21 Jul 2025 19:01:17 +0200
Subject: [PATCH 2/3] Add LOWER= to semantics test
---
flang/test/Semantics/c_f_pointer.f90 | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/flang/test/Semantics/c_f_pointer.f90 b/flang/test/Semantics/c_f_pointer.f90
index e2d00536cdacb..8a22175ffe19e 100644
--- a/flang/test/Semantics/c_f_pointer.f90
+++ b/flang/test/Semantics/c_f_pointer.f90
@@ -54,4 +54,12 @@ program test
call c_f_pointer(scalarC, c2ptr)
!WARNING: FPTR= argument to C_F_POINTER() should not have the non-interoperable intrinsic type or kind CHARACTER(KIND=4,LEN=1_8) [-Winteroperability]
call c_f_pointer(scalarC, unicodePtr)
+
+ !ERROR: SHAPE= argument to C_F_POINTER() may not appear when FPTR= is scalar
+ !ERROR: LOWER= argument to C_F_POINTER() may not appear when FPTR= is scalar
+ call c_f_pointer(scalarC, scalarIntF, [1_8], [0_8])
+ !ERROR: LOWER= argument to C_F_POINTER() must be a rank-one array.
+ call c_f_pointer(scalarC, arrayIntF, shape=[1_8], lower=rankTwoArray)
+ !ERROR: SHAPE= argument to C_F_POINTER() must appear when FPTR= is an array
+ call c_f_pointer(scalarC, arrayIntF, lower=[0])
end program
>From 117fe8e9e113e625d36f3fb6deca588e4ed23105 Mon Sep 17 00:00:00 2001
From: Michael Klemm <michael.klemm at amd.com>
Date: Mon, 21 Jul 2025 20:30:49 +0200
Subject: [PATCH 3/3] Add LOWER= to lowering test
---
flang/test/Lower/Intrinsics/c_f_pointer.f90 | 75 +++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/flang/test/Lower/Intrinsics/c_f_pointer.f90 b/flang/test/Lower/Intrinsics/c_f_pointer.f90
index 67817e39d5c2b..f41d5e471f540 100644
--- a/flang/test/Lower/Intrinsics/c_f_pointer.f90
+++ b/flang/test/Lower/Intrinsics/c_f_pointer.f90
@@ -140,3 +140,78 @@ subroutine dynamic_shape_size_2(cptr, fptr, shape, n)
! CHECK: %[[VAL_16:.*]] = fir.shape %[[VAL_11]], %[[VAL_15]] : (index, index) -> !fir.shape<2>
call c_f_pointer(cptr, fptr, shape)
end subroutine
+
+! CHECK-LABEL: func.func @_QPdynamic_shape_lower(
+subroutine dynamic_shape_lower(cptr, fpr, shape, lower)
+ use iso_c_binding
+ type(c_ptr) :: cptr
+ real, pointer :: fptr(:, :)
+ integer :: n
+ integer :: shape(:)
+ integer :: lower(:)
+! CHECK: %[[C_0:.*]] = arith.constant 0 : index
+! CHECK: %[[VAL_2:.*]] = fir.shape %[[C_0]], %[[C_0]] : (index, index) -> !fir.shape<2>
+! CHECK: %[[VAL_3:.*]] = fir.embox %[[VAL_1:.*]](%[[VAL_2]]) : (!fir.ptr<!fir.array<?x?xf32>>, !fir.shape<2>) -> !fir.box<!fir.ptr<!fir.array<?x?xf32>>>
+! CHECK: fir.store %[[VAL_3]] to %[[VAL_0:.*]] : !fir.ref<!fir.box<!fir.ptr<!fir.array<?x?xf32>>>>
+! CHECK: %[[VAL_4:.*]] = fir.alloca i32 {bindc_name = "n", uniq_name = "_QFdynamic_shape_lowerEn"}
+! CHECK: %[[VAL_5:.*]] = fir.coordinate_of %[[ARG_0:.*]], __address : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>) -> !fir.ref<i64>
+! CHECK: %[[VAL_6:.*]] = fir.load %[[VAL_5]] : !fir.ref<i64>
+! CHECK: %[[VAL_7:.*]] = fir.convert %[[VAL_6]] : (i64) -> !fir.ptr<!fir.array<?x?xf32>>
+! CHECK: %[[C_0:.*]]_0 = arith.constant 0 : index
+! CHECK: %[[VAL_8:.*]] = fir.coordinate_of %[[ARG_2:.*]], %[[C_0]]_0 : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+! CHECK: %[[VAL_9:.*]] = fir.load %[[VAL_8]] : !fir.ref<i32>
+! CHECK: %[[VAL_10:.*]] = fir.convert %[[VAL_9]] : (i32) -> index
+! CHECK: %[[C_1:.*]] = arith.constant 1 : index
+! CHECK: %[[VAL_11:.*]] = fir.coordinate_of %[[ARG_2:.*]], %[[C_1]] : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+! CHECK: %[[VAL_12:.*]] = fir.load %[[VAL_11]] : !fir.ref<i32>
+! CHECK: %[[VAL_13:.*]] = fir.convert %[[VAL_12]] : (i32) -> index
+! CHECK: %[[C_0:.*]]_1 = arith.constant 0 : index
+! CHECK: %[[VAL_14:.*]] = fir.coordinate_of %[[ARG_3:.*]], %[[C_0]]_1 : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+! CHECK: %[[VAL_15:.*]] = fir.load %[[VAL_14]] : !fir.ref<i32>
+! CHECK: %[[VAL_16:.*]] = fir.convert %[[VAL_15]] : (i32) -> index
+! CHECK: %[[C_1:.*]]_2 = arith.constant 1 : index
+! CHECK: %[[VAL_17:.*]] = fir.coordinate_of %[[ARG_3:.*]], %[[C_1]]_2 : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+! CHECK: %[[VAL_18:.*]] = fir.load %[[VAL_17]] : !fir.ref<i32>
+! CHECK: %[[VAL_19:.*]] = fir.convert %[[VAL_18]] : (i32) -> index
+! CHECK: %[[VAL_20:.*]] = fir.shape_shift %[[VAL_16]], %[[VAL_10]], %[[VAL_19]], %[[VAL_13]] : (index, index, index, index) -> !fir.shapeshift<2>
+! CHECK: %[[VAL_21:.*]] = fir.embox %[[VAL_7]](%[[VAL_20]]) : (!fir.ptr<!fir.array<?x?xf32>>, !fir.shapeshift<2>) -> !fir.box<!fir.ptr<!fir.array<?x?xf32>>>
+! CHECK: fir.store %[[VAL_21:.*]] to %[[VAL_0]] : !fir.ref<!fir.box<!fir.ptr<!fir.array<?x?xf32>>>>
+ call c_f_pointer(cptr, fptr, shape, lower)
+end subroutine dynamic_shape_lower
+
+! CHECK-LABEL: func.func @_QPdynamic_shape_lower_2(
+subroutine dynamic_shape_lower_2(cptr, fpr, shape, lower, n)
+ use iso_c_binding
+ type(c_ptr) :: cptr
+ real, pointer :: fptr(:, :)
+ integer :: n
+ integer :: shape(n)
+ integer :: lower(n)
+!CHECK: %[[C_0:.*]] = arith.constant 0 : index
+!CHECK: %[[VAL_2:.*]] = fir.shape %[[C_0]], %[[C_0]] : (index, index) -> !fir.shape<2>
+!CHECK: %[[VAL_3:.*]] = fir.embox %[[ARG1:.*]](%[[VAL_2]]) : (!fir.ptr<!fir.array<?x?xf32>>, !fir.shape<2>) -> !fir.box<!fir.ptr<!fir.array<?x?xf32>>>
+!CHECK: fir.store %[[VAL_3]] to %[[VAL_0:.*]] : !fir.ref<!fir.box<!fir.ptr<!fir.array<?x?xf32>>>>
+!CHECK: %[[VAL_4:.*]] = fir.coordinate_of %[[ARG_0:.*]], __address : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_ptr{__address:i64}>>) -> !fir.ref<i64>
+!CHECK: %[[VAL_5:.*]] = fir.load %[[VAL_4]] : !fir.ref<i64>
+!CHECK: %[[VAL_6:.*]] = fir.convert %[[VAL_5]] : (i64) -> !fir.ptr<!fir.array<?x?xf32>>
+!CHECK: %[[C_0:.*]]_0 = arith.constant 0 : index
+!CHECK: %[[VAL_7:.*]] = fir.coordinate_of %[[ARG_2:.*]], %[[C_0]]_0 : (!fir.ref<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+!CHECK: %[[VAL_8:.*]] = fir.load %[[VAL_7]] : !fir.ref<i32>
+!CHECK: %[[VAL_9:.*]] = fir.convert %[[VAL_8]] : (i32) -> index
+!CHECK: %[[C_1:.*]] = arith.constant 1 : index
+!CHECK: %[[VAL_10:.*]] = fir.coordinate_of %[[ARG_2]], %[[C_1]] : (!fir.ref<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+!CHECK: %[[VAL_11:.*]] = fir.load %[[VAL_10]] : !fir.ref<i32>
+!CHECK: %[[VAL_12:.*]] = fir.convert %[[VAL_11]] : (i32) -> index
+!CHECK: %[[C_0:.*]]_1 = arith.constant 0 : index
+!CHECK: %[[VAL_13:.*]] = fir.coordinate_of %[[ARG_3:.*]], %[[C_0]]_1 : (!fir.ref<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+!CHECK: %[[VAL_14:.*]] = fir.load %[[VAL_13]] : !fir.ref<i32>
+!CHECK: %[[VAL_15:.*]] = fir.convert %[[VAL_14]] : (i32) -> index
+!CHECK: %[[C_1:.*]]_2 = arith.constant 1 : index
+!CHECK: %[[VAL_16:.*]] = fir.coordinate_of %[[ARG_3]], %[[C_1]]_2 : (!fir.ref<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+!CHECK: %[[VAL_17:.*]] = fir.load %[[VAL_16]] : !fir.ref<i32>
+!CHECK: %[[VAL_18:.*]] = fir.convert %[[VAL_17]] : (i32) -> index
+!CHECK: %[[VAL_19:.*]] = fir.shape_shift %[[VAL_15]], %[[VAL_9]], %[[VAL_18]], %[[VAL_12]] : (index, index, index, index) -> !fir.shapeshift<2>
+!CHECK: %[[VAL_20:.*]] = fir.embox %[[VAL_6]](%[[VAL_19]]) : (!fir.ptr<!fir.array<?x?xf32>>, !fir.shapeshift<2>
+!CHECK: fir.store %[[VAL_20]] to %[[VAL_0]] : !fir.ref<!fir.box<!fir.ptr<!fir.array<?x?xf32>>>>
+ call c_f_pointer(cptr, fptr, shape, lower)
+end subroutine dynamic_shape_lower_2
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