Fix -finit-derived for c_ptr and c_funptr in programs which use

    iso_c_binding.

    gcc/fortran/ChangeLog:

    2018-06-25  Fritz Reese  <fritzoreese@gmail.com>

	PR fortran/82972
        PR fortran/83088
        PR fortran/85851
	* expr.c (component_initializer): Assign init expr to c->initializer.
	(generate_isocbinding_initializer): New.
	(gfc_generate_initializer): Call generate_isocbinding_initializer to
	generate initializers for c_ptr and c_funptr with -finit-derived.

    gcc/testsuite/ChangeLog:

    2018-06-25  Fritz Reese  <fritzoreese@gmail.com>

	PR fortran/82972
        PR fortran/83088
        PR fortran/85851
	* gfortran.dg/init_flag_17.f90: New testcase.

From-SVN: r262104

1 files changed, 31 insertions, 1 deletions

diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index a1336d2..a799a49 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -4493,7 +4493,7 @@ component_initializer (gfc_typespec *ts, gfc_component *c, bool generate)
       gfc_apply_init (&c->ts, &c->attr, init);
     }
 
-  return init;
+  return (c->initializer = init);
 }
 
 
@@ -4505,6 +4505,32 @@ gfc_default_initializer (gfc_typespec *ts)
   return gfc_generate_initializer (ts, false);
 }
 
+/* Generate an initializer expression for an iso_c_binding type
+   such as c_[fun]ptr. The appropriate initializer is c_null_[fun]ptr.  */
+
+static gfc_expr *
+generate_isocbinding_initializer (gfc_symbol *derived)
+{
+  /* The initializers have already been built into the c_null_[fun]ptr symbols
+     from gen_special_c_interop_ptr.  */
+  gfc_symtree *npsym = NULL;
+  if (0 == strcmp (derived->name, "c_ptr"))
+    gfc_find_sym_tree ("c_null_ptr", gfc_current_ns, true, &npsym);
+  else if (0 == strcmp (derived->name, "c_funptr"))
+    gfc_find_sym_tree ("c_null_funptr", gfc_current_ns, true, &npsym);
+  else
+    gfc_internal_error ("generate_isocbinding_initializer(): bad iso_c_binding"
+			" type, expected %<c_ptr%> or %<c_funptr%>");
+  if (npsym)
+    {
+      gfc_expr *init = gfc_copy_expr (npsym->n.sym->value);
+      init->symtree = npsym;
+      init->ts.is_iso_c = true;
+      return init;
+    }
+
+  return NULL;
+}
 
 /* Get or generate an expression for a default initializer of a derived type.
    If -finit-derived is specified, generate default initialization expressions
@@ -4515,8 +4541,12 @@ gfc_generate_initializer (gfc_typespec *ts, bool generate)
 {
   gfc_expr *init, *tmp;
   gfc_component *comp;
+
   generate = flag_init_derived && generate;
 
+  if (ts->u.derived->ts.is_iso_c && generate)
+    return generate_isocbinding_initializer (ts->u.derived);
+
   /* See if we have a default initializer in this, but not in nested
      types (otherwise we could use gfc_has_default_initializer()).
      We don't need to check if we are going to generate them.  */