1 files changed, 59 insertions, 0 deletions
diff --git a/gcc/tree.c b/gcc/tree.c
index 53f46f3..a70b1b2 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -4151,6 +4151,65 @@ int_fits_type_p (c, type)
     }
 }
 
+/* Returns true if T is, contains, or refers to a type with variable
+   size.  This concept is more general than that of C99 'variably
+   modified types': in C99, a struct type is never variably modified
+   because a VLA may not appear as a structure member.  However, in
+   GNU C code like:
+    
+     struct S { int i[f()]; };
+
+   is valid, and other languages may define similar constructs.  */
+
+bool
+variably_modified_type_p (type)
+     tree type;
+{
+  /* If TYPE itself has variable size, it is variably modified.  
+
+     We do not yet have a representation of the C99 '[*]' syntax.
+     When a representation is chosen, this function should be modified
+     to test for that case as well.  */
+  if (TYPE_SIZE (type) 
+      && TYPE_SIZE (type) != error_mark_node
+      && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
+    return true;
+
+  /* If TYPE is a pointer or reference, it is variably modified if 
+     the type pointed to is variably modified.  */
+  if ((TREE_CODE (type) == POINTER_TYPE
+       || TREE_CODE (type) == REFERENCE_TYPE)
+      && variably_modified_type_p (TREE_TYPE (type)))
+    return true;
+  
+  /* If TYPE is an array, it is variably modified if the array
+     elements are.  (Note that the VLA case has already been checked
+     above.)  */
+  if (TREE_CODE (type) == ARRAY_TYPE
+      && variably_modified_type_p (TREE_TYPE (type)))
+    return true;
+
+  /* If TYPE is a function type, it is variably modified if any of the
+     parameters or the return type are variably modified.  */
+  if (TREE_CODE (type) == FUNCTION_TYPE
+      || TREE_CODE (type) == METHOD_TYPE)
+    {
+      tree parm;
+
+      if (variably_modified_type_p (TREE_TYPE (type)))
+	return true;
+      for (parm = TYPE_ARG_TYPES (type); 
+	   parm && parm != void_list_node; 
+	   parm = TREE_CHAIN (parm))
+	if (variably_modified_type_p (TREE_VALUE (parm)))
+	  return true;
+    }
+
+  /* The current language may have other cases to check, but in general,
+     all other types are not variably modified.  */
+  return (*lang_hooks.tree_inlining.var_mod_type_p) (type);
+}
+
 /* Given a DECL or TYPE, return the scope in which it was declared, or
    NULL_TREE if there is no containing scope.  */