openmp: Copy DECL_LANG_SPECIFIC and DECL_LANG_FLAG_? to tree-nested decl copy [PR114825]

tree-nested.cc creates in 2 spots artificial VAR_DECLs, one of them is used
both for debug info and OpenMP/OpenACC lowering purposes, the other solely for
OpenMP/OpenACC lowering purposes.
When the decls are used in OpenMP/OpenACC lowering, the OMP langhooks (mostly
Fortran, C just a little and C++ doesn't have nested functions) then inspect
the flags on the vars and based on that decide how to lower the corresponding
clauses.

Unfortunately we weren't copying DECL_LANG_SPECIFIC and DECL_LANG_FLAG_?, so
the langhooks made decisions on the default flags on those instead.
As the original decl isn't necessarily a VAR_DECL, could be e.g. PARM_DECL,
using copy_node wouldn't work properly, so this patch just copies those
flags in addition to other flags it was copying already.  And I've removed
code duplication by introducing a helper function which does copying common
to both uses.

2024-04-25  Jakub Jelinek  <jakub@redhat.com>

	PR fortran/114825
	* tree-nested.cc (get_debug_decl): New function.
	(get_nonlocal_debug_decl): Use it.
	(get_local_debug_decl): Likewise.

	* gfortran.dg/gomp/pr114825.f90: New test.

gcc/testsuite/gfortran.dg/gomp/pr114825.f90

@@ -0,0 +1,16 @@
+! PR fortran/114825
+
+subroutine pr114825(b)
+  type t
+    real, allocatable :: m(:)
+  end type t
+  type(t), allocatable, target :: b(:)
+  type(t), pointer :: d
+  !$omp parallel private(d)
+  d => b(1)
+  !$omp end parallel
+contains
+  subroutine sub
+    d => b(1)
+  end subroutine sub
+end subroutine pr114825

gcc/tree-nested.cc

@@ -1047,6 +1047,37 @@ get_frame_field (struct nesting_info *info, tree target_context,
 
 static void note_nonlocal_vla_type (struct nesting_info *info, tree type);
 
+/* Helper for get_nonlocal_debug_decl and get_local_debug_decl.  */
+
+static tree
+get_debug_decl (tree decl)
+{
+  tree new_decl
+    = build_decl (DECL_SOURCE_LOCATION (decl),
+		  VAR_DECL, DECL_NAME (decl), TREE_TYPE (decl));
+  DECL_ARTIFICIAL (new_decl) = DECL_ARTIFICIAL (decl);
+  DECL_IGNORED_P (new_decl) = DECL_IGNORED_P (decl);
+  TREE_THIS_VOLATILE (new_decl) = TREE_THIS_VOLATILE (decl);
+  TREE_SIDE_EFFECTS (new_decl) = TREE_SIDE_EFFECTS (decl);
+  TREE_READONLY (new_decl) = TREE_READONLY (decl);
+  TREE_ADDRESSABLE (new_decl) = TREE_ADDRESSABLE (decl);
+  DECL_SEEN_IN_BIND_EXPR_P (new_decl) = 1;
+  if ((TREE_CODE (decl) == PARM_DECL
+       || TREE_CODE (decl) == RESULT_DECL
+       || VAR_P (decl))
+      && DECL_BY_REFERENCE (decl))
+    DECL_BY_REFERENCE (new_decl) = 1;
+  /* Copy DECL_LANG_SPECIFIC and DECL_LANG_FLAG_* for OpenMP langhook
+     purposes.  */
+  DECL_LANG_SPECIFIC (new_decl) = DECL_LANG_SPECIFIC (decl);
+#define COPY_DLF(n) DECL_LANG_FLAG_##n (new_decl) = DECL_LANG_FLAG_##n (decl)
+  COPY_DLF (0); COPY_DLF (1); COPY_DLF (2); COPY_DLF (3);
+  COPY_DLF (4); COPY_DLF (5); COPY_DLF (6); COPY_DLF (7);
+  COPY_DLF (8);
+#undef COPY_DLF
+  return new_decl;
+}
+
 /* A subroutine of convert_nonlocal_reference_op.  Create a local variable
    in the nested function with DECL_VALUE_EXPR set to reference the true
    variable in the parent function.  This is used both for debug info
@@ -1094,21 +1125,8 @@ get_nonlocal_debug_decl (struct nesting_info *info, tree decl)
     x = build_simple_mem_ref_notrap (x);
 
   /* ??? We should be remapping types as well, surely.  */
-  new_decl = build_decl (DECL_SOURCE_LOCATION (decl),
+  new_decl = get_debug_decl (decl);
-			 VAR_DECL, DECL_NAME (decl), TREE_TYPE (decl));
   DECL_CONTEXT (new_decl) = info->context;
-  DECL_ARTIFICIAL (new_decl) = DECL_ARTIFICIAL (decl);
-  DECL_IGNORED_P (new_decl) = DECL_IGNORED_P (decl);
-  TREE_THIS_VOLATILE (new_decl) = TREE_THIS_VOLATILE (decl);
-  TREE_SIDE_EFFECTS (new_decl) = TREE_SIDE_EFFECTS (decl);
-  TREE_READONLY (new_decl) = TREE_READONLY (decl);
-  TREE_ADDRESSABLE (new_decl) = TREE_ADDRESSABLE (decl);
-  DECL_SEEN_IN_BIND_EXPR_P (new_decl) = 1;
-  if ((TREE_CODE (decl) == PARM_DECL
-       || TREE_CODE (decl) == RESULT_DECL
-       || VAR_P (decl))
-      && DECL_BY_REFERENCE (decl))
-    DECL_BY_REFERENCE (new_decl) = 1;
 
   SET_DECL_VALUE_EXPR (new_decl, x);
   DECL_HAS_VALUE_EXPR_P (new_decl) = 1;
@@ -1892,21 +1910,8 @@ get_local_debug_decl (struct nesting_info *info, tree decl, tree field)
   x = info->frame_decl;
   x = build3 (COMPONENT_REF, TREE_TYPE (field), x, field, NULL_TREE);
 
-  new_decl = build_decl (DECL_SOURCE_LOCATION (decl),
+  new_decl = get_debug_decl (decl);
-			 VAR_DECL, DECL_NAME (decl), TREE_TYPE (decl));
   DECL_CONTEXT (new_decl) = info->context;
-  DECL_ARTIFICIAL (new_decl) = DECL_ARTIFICIAL (decl);
-  DECL_IGNORED_P (new_decl) = DECL_IGNORED_P (decl);
-  TREE_THIS_VOLATILE (new_decl) = TREE_THIS_VOLATILE (decl);
-  TREE_SIDE_EFFECTS (new_decl) = TREE_SIDE_EFFECTS (decl);
-  TREE_READONLY (new_decl) = TREE_READONLY (decl);
-  TREE_ADDRESSABLE (new_decl) = TREE_ADDRESSABLE (decl);
-  DECL_SEEN_IN_BIND_EXPR_P (new_decl) = 1;
-  if ((TREE_CODE (decl) == PARM_DECL
-       || TREE_CODE (decl) == RESULT_DECL
-       || VAR_P (decl))
-      && DECL_BY_REFERENCE (decl))
-    DECL_BY_REFERENCE (new_decl) = 1;
 
   SET_DECL_VALUE_EXPR (new_decl, x);
   DECL_HAS_VALUE_EXPR_P (new_decl) = 1;