[flang] lower c_f_procpointer (#76071)

This is equivalent to a procedure pointer assignment, except that the
target is a C_FUNPTR.

flang/include/flang/Optimizer/Builder/IntrinsicCall.h

@@ -202,6 +202,7 @@ struct IntrinsicLibrary {
   fir::ExtendedValue genCAssociatedCPtr(mlir::Type,
                                         llvm::ArrayRef<fir::ExtendedValue>);
   void genCFPointer(llvm::ArrayRef<fir::ExtendedValue>);
+  void genCFProcPointer(llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genCFunLoc(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genCLoc(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   void genDateAndTime(llvm::ArrayRef<fir::ExtendedValue>);

flang/lib/Optimizer/Builder/IntrinsicCall.cpp

@@ -165,6 +165,10 @@ static constexpr IntrinsicHandler handlers[]{
        {"fptr", asInquired},
        {"shape", asAddr, handleDynamicOptional}}},
      /*isElemental=*/false},
+    {"c_f_procpointer",
+     &I::genCFProcPointer,
+     {{{"cptr", asValue}, {"fptr", asInquired}}},
+     /*isElemental=*/false},
     {"c_funloc", &I::genCFunLoc, {{{"x", asBox}}}, /*isElemental=*/false},
     {"c_loc", &I::genCLoc, {{{"x", asBox}}}, /*isElemental=*/false},
     {"ceiling", &I::genCeiling},
@@ -2525,6 +2529,22 @@ void IntrinsicLibrary::genCFPointer(llvm::ArrayRef<fir::ExtendedValue> args) {
                                     /*lbounds=*/mlir::ValueRange{});
 }
 
+// C_F_PROCPOINTER
+void IntrinsicLibrary::genCFProcPointer(
+    llvm::ArrayRef<fir::ExtendedValue> args) {
+  assert(args.size() == 2);
+  mlir::Value cptr =
+      fir::factory::genCPtrOrCFunptrValue(builder, loc, fir::getBase(args[0]));
+  mlir::Value fptr = fir::getBase(args[1]);
+  auto boxProcType =
+      mlir::cast<fir::BoxProcType>(fir::unwrapRefType(fptr.getType()));
+  mlir::Value cptrCast =
+      builder.createConvert(loc, boxProcType.getEleTy(), cptr);
+  mlir::Value cptrBox =
+      builder.create<fir::EmboxProcOp>(loc, boxProcType, cptrCast);
+  builder.create<fir::StoreOp>(loc, cptrBox, fptr);
+}
+
 // C_FUNLOC
 fir::ExtendedValue
 IntrinsicLibrary::genCFunLoc(mlir::Type resultType,

flang/test/Lower/Intrinsics/c_f_procpointer.f90

@@ -0,0 +1,42 @@
+! Test C_F_PROCPOINTER() lowering.
+! RUN: bbc -emit-hlfir -o - %s | FileCheck %s
+
+subroutine test_c_funloc(fptr, cptr)
+  use iso_c_binding, only : c_f_procpointer, c_funptr
+  real, pointer, external :: fptr
+  type(c_funptr), cptr
+  call c_f_procpointer(cptr, fptr)
+end subroutine
+! CHECK-LABEL:   func.func @_QPtest_c_funloc(
+! CHECK-SAME:                                %[[VAL_0:.*]]: !fir.ref<!fir.boxproc<() -> ()>>,
+! CHECK-SAME:                                %[[VAL_1:.*]]: !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>> {fir.bindc_name = "cptr"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest_c_funlocEcptr"} : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>) -> (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>, !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_0]] {fortran_attrs = #fir.var_attrs<pointer>, uniq_name = "_QFtest_c_funlocEfptr"} : (!fir.ref<!fir.boxproc<() -> ()>>) -> (!fir.ref<!fir.boxproc<() -> ()>>, !fir.ref<!fir.boxproc<() -> ()>>)
+! CHECK:           %[[VAL_4:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>
+! CHECK:           %[[VAL_5:.*]] = fir.coordinate_of %[[VAL_2]]#1, %[[VAL_4]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+! CHECK:           %[[VAL_6:.*]] = fir.load %[[VAL_5]] : !fir.ref<i64>
+! CHECK:           %[[VAL_7:.*]] = fir.convert %[[VAL_6]] : (i64) -> (() -> ())
+! CHECK:           %[[VAL_8:.*]] = fir.emboxproc %[[VAL_7]] : (() -> ()) -> !fir.boxproc<() -> ()>
+! CHECK:           fir.store %[[VAL_8]] to %[[VAL_3]]#1 : !fir.ref<!fir.boxproc<() -> ()>>
+
+subroutine test_c_funloc_char(fptr, cptr)
+  use iso_c_binding, only : c_f_procpointer, c_funptr
+  interface
+    character(10) function char_func()
+    end function
+  end interface
+  procedure(char_func), pointer :: fptr
+  type(c_funptr), cptr
+  call c_f_procpointer(cptr, fptr)
+end subroutine
+! CHECK-LABEL:   func.func @_QPtest_c_funloc_char(
+! CHECK-SAME:                                     %[[VAL_0:.*]]: !fir.ref<!fir.boxproc<() -> ()>>,
+! CHECK-SAME:                                     %[[VAL_1:.*]]: !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>> {fir.bindc_name = "cptr"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest_c_funloc_charEcptr"} : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>) -> (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>, !fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_0]] {fortran_attrs = #fir.var_attrs<pointer>, uniq_name = "_QFtest_c_funloc_charEfptr"} : (!fir.ref<!fir.boxproc<() -> ()>>) -> (!fir.ref<!fir.boxproc<() -> ()>>, !fir.ref<!fir.boxproc<() -> ()>>)
+! CHECK:           %[[VAL_4:.*]] = fir.field_index __address, !fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>
+! CHECK:           %[[VAL_5:.*]] = fir.coordinate_of %[[VAL_2]]#1, %[[VAL_4]] : (!fir.ref<!fir.type<_QM__fortran_builtinsT__builtin_c_funptr{__address:i64}>>, !fir.field) -> !fir.ref<i64>
+! CHECK:           %[[VAL_6:.*]] = fir.load %[[VAL_5]] : !fir.ref<i64>
+! CHECK:           %[[VAL_7:.*]] = fir.convert %[[VAL_6]] : (i64) -> (() -> ())
+! CHECK:           %[[VAL_8:.*]] = fir.emboxproc %[[VAL_7]] : (() -> ()) -> !fir.boxproc<() -> ()>
+! CHECK:           fir.store %[[VAL_8]] to %[[VAL_3]]#1 : !fir.ref<!fir.boxproc<() -> ()>>