OpenMP/Fortran: Fix handling of 'declare target' with 'link' clause [PR115559]

Contrary to a normal 'declare target', the 'declare target link' attribute
also needs to set node->offloadable and push the offload_vars in the front end.

Linked variables require that the data is mapped. For module variables, this
can happen anywhere. For variables in an external subprograms or the main
programm, this can only happen in the either that program itself or in an
internal subprogram. - Whether a variable is just normally mapped or linked then
becomes relevant if a device routine exists that can access that variable,
i.e. an internal procedure has then to be marked as declare target.

	PR fortran/115559

gcc/fortran/ChangeLog:

	* trans-common.cc (build_common_decl): Add 'omp declare target' and
	'omp declare target link' variables to offload_vars.
	* trans-decl.cc (add_attributes_to_decl): Likewise; update args and
	call decl_attributes.
	(get_proc_pointer_decl, gfc_get_extern_function_decl,
	build_function_decl): Update calls.
	(gfc_get_symbol_decl): Likewise; move after 'DECL_STATIC (t)=1'
	to avoid errors with symtab_node::get_create.

libgomp/ChangeLog:

	* testsuite/libgomp.fortran/declare-target-link.f90: New test.

1 files changed, 55 insertions, 26 deletions

diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index 82fa2bb..0fdc41b 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -46,7 +46,9 @@ along with GCC; see the file COPYING3.  If not see
 #include "trans-stmt.h"
 #include "gomp-constants.h"
 #include "gimplify.h"
+#include "context.h"
 #include "omp-general.h"
+#include "omp-offload.h"
 #include "attr-fnspec.h"
 #include "tree-iterator.h"
 #include "dependency.h"
@@ -1472,19 +1474,18 @@ gfc_add_assign_aux_vars (gfc_symbol * sym)
 }
 
 
-static tree
-add_attributes_to_decl (symbol_attribute sym_attr, tree list)
+static void
+add_attributes_to_decl (tree *decl_p, const gfc_symbol *sym)
 {
   unsigned id;
-  tree attr;
+  tree list = NULL_TREE;
+  symbol_attribute sym_attr = sym->attr;
 
   for (id = 0; id < EXT_ATTR_NUM; id++)
     if (sym_attr.ext_attr & (1 << id) && ext_attr_list[id].middle_end_name)
       {
-	attr = build_tree_list (
-		 get_identifier (ext_attr_list[id].middle_end_name),
-				 NULL_TREE);
-	list = chainon (list, attr);
+	tree ident = get_identifier (ext_attr_list[id].middle_end_name);
+	list = tree_cons (ident, NULL_TREE, list);
       }
 
   tree clauses = NULL_TREE;
@@ -1547,6 +1548,7 @@ add_attributes_to_decl (symbol_attribute sym_attr, tree list)
       clauses = c;
     }
 
+  bool has_declare = true;
   if (sym_attr.omp_declare_target_link
       || sym_attr.oacc_declare_link)
     list = tree_cons (get_identifier ("omp declare target link"),
@@ -1558,12 +1560,45 @@ add_attributes_to_decl (symbol_attribute sym_attr, tree list)
 	   || sym_attr.oacc_declare_device_resident)
     list = tree_cons (get_identifier ("omp declare target"),
 		      clauses, list);
+  else
+    has_declare = false;
 
   if (sym_attr.omp_declare_target_indirect)
     list = tree_cons (get_identifier ("omp declare target indirect"),
 		      clauses, list);
 
-  return list;
+  decl_attributes (decl_p, list, 0);
+
+  if (has_declare
+      && VAR_P (*decl_p)
+      && sym->ns->proc_name->attr.flavor != FL_MODULE)
+    {
+      has_declare = false;
+      for (gfc_namespace* ns = sym->ns->contained; ns; ns = ns->sibling)
+	if (ns->proc_name->attr.omp_declare_target)
+	  {
+	    has_declare = true;
+	    break;
+	  }
+    }
+
+  if (has_declare && VAR_P (*decl_p) && has_declare)
+    {
+      /* Add to offload_vars; get_create does so for omp_declare_target,
+	 omp_declare_target_link requires manual work.  */
+      gcc_assert (symtab_node::get (*decl_p) == 0);
+      symtab_node *node = symtab_node::get_create (*decl_p);
+      if (node != NULL && sym_attr.omp_declare_target_link)
+	{
+	  node->offloadable = 1;
+	  if (ENABLE_OFFLOADING)
+	    {
+	      g->have_offload = true;
+	      if (is_a <varpool_node *> (node))
+		vec_safe_push (offload_vars, *decl_p);
+	    }
+	}
+    }
 }
 
 
@@ -1578,7 +1613,6 @@ gfc_get_symbol_decl (gfc_symbol * sym)
 {
   tree decl;
   tree length = NULL_TREE;
-  tree attributes;
   int byref;
   bool intrinsic_array_parameter = false;
   bool fun_or_res;
@@ -1864,12 +1898,6 @@ gfc_get_symbol_decl (gfc_symbol * sym)
   decl = build_decl (gfc_get_location (&sym->declared_at),
 		     VAR_DECL, gfc_sym_identifier (sym), gfc_sym_type (sym));
 
-  /* Add attributes to variables.  Functions are handled elsewhere.  */
-  attributes = add_attributes_to_decl (sym->attr, NULL_TREE);
-  decl_attributes (&decl, attributes, 0);
-  if (sym->ts.deferred && VAR_P (length))
-    decl_attributes (&length, attributes, 0);
-
   /* Symbols from modules should have their assembler names mangled.
      This is done here rather than in gfc_finish_var_decl because it
      is different for string length variables.  */
@@ -2035,6 +2063,12 @@ gfc_get_symbol_decl (gfc_symbol * sym)
 	TREE_READONLY (decl) = 1;
     }
 
+  /* Add attributes to variables.  Functions are handled elsewhere.  */
+  add_attributes_to_decl (&decl, sym);
+
+  if (sym->ts.deferred && VAR_P (length))
+    decl_attributes (&length, DECL_ATTRIBUTES (decl), 0);
+
   return decl;
 }
 
@@ -2071,7 +2105,6 @@ static tree
 get_proc_pointer_decl (gfc_symbol *sym)
 {
   tree decl;
-  tree attributes;
 
   if (sym->module || sym->fn_result_spec)
     {
@@ -2151,8 +2184,7 @@ get_proc_pointer_decl (gfc_symbol *sym)
       && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)))
     set_decl_tls_model (decl, decl_default_tls_model (decl));
 
-  attributes = add_attributes_to_decl (sym->attr, NULL_TREE);
-  decl_attributes (&decl, attributes, 0);
+  add_attributes_to_decl (&decl, sym);
 
   return decl;
 }
@@ -2166,7 +2198,6 @@ gfc_get_extern_function_decl (gfc_symbol * sym, gfc_actual_arglist *actual_args,
 {
   tree type;
   tree fndecl;
-  tree attributes;
   gfc_expr e;
   gfc_intrinsic_sym *isym;
   gfc_expr argexpr;
@@ -2364,8 +2395,7 @@ module_sym:
   DECL_EXTERNAL (fndecl) = 1;
   TREE_PUBLIC (fndecl) = 1;
 
-  attributes = add_attributes_to_decl (sym->attr, NULL_TREE);
-  decl_attributes (&fndecl, attributes, 0);
+  add_attributes_to_decl (&fndecl, sym);
 
   gfc_set_decl_assembler_name (fndecl, mangled_name);
 
@@ -2424,7 +2454,7 @@ module_sym:
 static void
 build_function_decl (gfc_symbol * sym, bool global)
 {
-  tree fndecl, type, attributes;
+  tree fndecl, type;
   symbol_attribute attr;
   tree result_decl;
   gfc_formal_arglist *f;
@@ -2475,15 +2505,14 @@ build_function_decl (gfc_symbol * sym, bool global)
   if (sym->attr.referenced || sym->attr.entry_master)
     TREE_USED (fndecl) = 1;
 
-  attributes = add_attributes_to_decl (attr, NULL_TREE);
-  decl_attributes (&fndecl, attributes, 0);
+  add_attributes_to_decl (&fndecl, sym);
 
   /* Figure out the return type of the declared function, and build a
      RESULT_DECL for it.  If this is a subroutine with alternate
      returns, build a RESULT_DECL for it.  */
   result_decl = NULL_TREE;
   /* TODO: Shouldn't this just be TREE_TYPE (TREE_TYPE (fndecl)).  */
-  if (attr.function)
+  if (sym->attr.function)
     {
       if (gfc_return_by_reference (sym))
 	type = void_type_node;
@@ -2530,7 +2559,7 @@ build_function_decl (gfc_symbol * sym, bool global)
   /* Set attributes for PURE functions. A call to a PURE function in the
      Fortran 95 sense is both pure and without side effects in the C
      sense.  */
-  if (attr.pure || attr.implicit_pure)
+  if (sym->attr.pure || sym->attr.implicit_pure)
     {
       /* TODO: check if a pure SUBROUTINE has no INTENT(OUT) arguments
 	 including an alternate return. In that case it can also be