Hi,
in my tree I run the type chekcer from dwarf2out and tree streamer and it
reports non-NULL TREE_PURPOSE in TYPE_ARG_TYPES during bootstrap.
This is because C++ FE uses it to store the initial value.
This patch updates verifier to permit this case and free_lang_data_in_type to
clear it. I am going to commit this as obvious (The checks will trigger often
on LTO builds even in mainline)
I also added documentation. I think dwarf2out may be interested to output this
so one don't need to specify the value from debugger.
Bootstrapped/regtested x86_64-linux
Honza
* tree.c (free_lang_data_in_type): Free TREE_PURPOSE of
TYPE_ARG_TYPES list.
(verify_type): Permit non-NULL TREE_PURPOSE in non-LTO builds.
* tree.def (FUNCTION_TYPE): Document TREE_PURPOSE in TYPE_ARG_TYPES
Index: tree.c
===================================================================
--- tree.c (revision 222981)
+++ tree.c (working copy)
@@ -5041,6 +5041,8 @@ free_lang_data_in_type (tree type)
TREE_VALUE (p) = build_qualified_type (arg_type, quals);
free_lang_data_in_type (TREE_VALUE (p));
}
+ /* C++ FE uses TREE_PURPOSE to store initial values. */
+ TREE_PURPOSE (p) = NULL;
}
}
@@ -12817,7 +12831,8 @@ verify_type (const_tree t)
else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE)
for (tree l = TYPE_ARG_TYPES (t); l; l = TREE_CHAIN (l))
{
- if (TREE_PURPOSE (l))
+ /* C++ FE uses TREE_PURPOSE to store initial values. */
+ if (TREE_PURPOSE (l) && in_lto_p)
{
error ("TREE_PURPOSE is non-NULL in TYPE_ARG_TYPES list");
debug_tree (l);
Index: tree.def
===================================================================
--- tree.def (revision 222981)
+++ tree.def (working copy)
@@ -245,6 +245,8 @@ DEFTREECODE (POINTER_BOUNDS_TYPE, "point
TREE_TYPE type of value returned.
TYPE_ARG_TYPES list of types of arguments expected.
this list is made of TREE_LIST nodes.
+ In this list TREE_PURPOSE can be used to indicate the default
+ value of parameter (used by C++ frontend).
Types of "Procedures" in languages where they are different from functions
have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
DEFTREECODE (FUNCTION_TYPE, "function_type", tcc_type, 0)
