[flang][debug] Support fir::ReferenceType.

[abidh]

No description provided.

[llvmbot]

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

Author: Abid Qadeer (abidh)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/113480.diff

2 Files Affected:

• (modified) flang/lib/Optimizer/Transforms/DebugTypeGenerator.cpp (+5)
• (added) flang/test/Transforms/debug-ref-type.fir (+10)

diff --git a/flang/lib/Optimizer/Transforms/DebugTypeGenerator.cpp b/flang/lib/Optimizer/Transforms/DebugTypeGenerator.cpp
index 71e534b4f2e2a3..84f7873a9fd009 100644
--- a/flang/lib/Optimizer/Transforms/DebugTypeGenerator.cpp
+++ b/flang/lib/Optimizer/Transforms/DebugTypeGenerator.cpp
@@ -511,6 +511,11 @@ DebugTypeGenerator::convertType(mlir::Type Ty, mlir::LLVM::DIFileAttr fileAttr,
                                 /*hasDescriptor=*/false);
   } else if (auto recTy = mlir::dyn_cast_or_null<fir::RecordType>(Ty)) {
     return convertRecordType(recTy, fileAttr, scope, declOp);
+  } else if (auto refTy = mlir::dyn_cast_if_present<fir::ReferenceType>(Ty)) {
+    auto elTy = refTy.getEleTy();
+    return convertPointerLikeType(elTy, fileAttr, scope, declOp,
+                                  /*genAllocated=*/false,
+                                  /*genAssociated=*/false);
   } else if (auto boxTy = mlir::dyn_cast_or_null<fir::BoxType>(Ty)) {
     auto elTy = boxTy.getElementType();
     if (auto seqTy = mlir::dyn_cast_or_null<fir::SequenceType>(elTy))
diff --git a/flang/test/Transforms/debug-ref-type.fir b/flang/test/Transforms/debug-ref-type.fir
new file mode 100644
index 00000000000000..2b3af485385d8a
--- /dev/null
+++ b/flang/test/Transforms/debug-ref-type.fir
@@ -0,0 +1,10 @@
+// RUN: fir-opt --add-debug-info --mlir-print-debuginfo %s | FileCheck %s
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<>} {
+  func.func private @_FortranAioBeginExternalListOutput(i8) -> !fir.ref<i8> loc(#loc1)
+}
+#loc1 = loc("test.f90":5:1)
+
+// CHECK: #[[INT8_TY:.*]] = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "integer", sizeInBits = 8, encoding = DW_ATE_signed>
+// CHECK: #[[REF_TY:.*]] = #llvm.di_derived_type<tag = DW_TAG_pointer_type, name = "", baseType = #[[INT8_TY]]{{.*}}>
+// CHECK: #llvm.di_subroutine_type<{{.*}}types = #[[REF_TY]], #[[INT8_TY]]>

[jeanPerier]

Could you also verify the handling of !fir.ref<none>?

This will for instance be generated for the signature of foo after the abtsract-result pass:

subroutine test() 
  use iso_c_binding, only : c_ptr
  interface
  function foo() bind(c) 
    import :: c_ptr
    type(c_ptr) foo
  end function
  end interface
  call bar(foo())
end subroutine

func.func private @foo() -> !fir.ref<none> attributes {fir.bindc_name = "foo", fir.proc_attrs = #fir.proc_attrs<bind_c>}

[abidh]

Thanks for your review. Currently mlir::NoneType is not handled and a place holder integer type gets generated for it. I have a small PR ready to add its support and I will add the !fir.ref<none> check in that.