-
-/* Subroutine of pushdecl.
-
- X is a TYPE_DECL for a typedef statement. Create a brand new
- ..._TYPE node (which will be just a variant of the existing
- ..._TYPE node with identical properties) and then install X
- as the TYPE_NAME of this brand new (duplicate) ..._TYPE node.
-
- The whole point here is to end up with a situation where each
- and every ..._TYPE node the compiler creates will be uniquely
- associated with AT MOST one node representing a typedef name.
- This way, even though the compiler substitutes corresponding
- ..._TYPE nodes for TYPE_DECL (i.e. "typedef name") nodes very
- early on, later parts of the compiler can always do the reverse
- translation and get back the corresponding typedef name. For
- example, given:
-
- typedef struct S MY_TYPE;
- MY_TYPE object;
-
- Later parts of the compiler might only know that `object' was of
- type `struct S' if it were not for code just below. With this
- code however, later parts of the compiler see something like:
-
- struct S' == struct S
- typedef struct S' MY_TYPE;
- struct S' object;
-
- And they can then deduce (from the node for type struct S') that
- the original object declaration was:
-
- MY_TYPE object;
-
- Being able to do this is important for proper support of protoize,
- and also for generating precise symbolic debugging information
- which takes full account of the programmer's (typedef) vocabulary.
-
- Obviously, we don't want to generate a duplicate ..._TYPE node if
- the TYPE_DECL node that we are now processing really represents a
- standard built-in type. */
-
-static void
-clone_underlying_type (tree x)
-{
- if (DECL_IS_BUILTIN (x))
- {
- if (TYPE_NAME (TREE_TYPE (x)) == 0)
- TYPE_NAME (TREE_TYPE (x)) = x;
- }
- else if (TREE_TYPE (x) != error_mark_node
- && DECL_ORIGINAL_TYPE (x) == NULL_TREE)
- {
- tree tt = TREE_TYPE (x);
- DECL_ORIGINAL_TYPE (x) = tt;
- tt = build_variant_type_copy (tt);
- TYPE_NAME (tt) = x;
- TREE_USED (tt) = TREE_USED (x);
- TREE_TYPE (x) = tt;
- }
-}
-