Support GTY((cache)) on hash_map.

gcc/
	* hash-traits.h (ggc_remove): Add ggc_maybe_mx member function.
	(ggc_cache_remove): Override it instead of ggc_mx.
	* hash-table.h (gt_ggc_mx): Call it instead of ggc_mx.
	(gt_cleare_cache): Call ggc_mx instead of gt_ggc_mx.
	* hash-map-traits.h (simple_hashmap_traits): Add maybe_mx member.
	(simple_cache_map_traits): Override maybe_mx.
	* hash-map.h (hash_entry): Add ggc_maybe_mx and keep_cache_entry.
	(hash_map): Friend gt_cleare_cache.
	(gt_cleare_cache): New.
	* tree.h (tree_cache_traits): New hash_map traits class.
	(tree_cache_map): New typedef.
gcc/cp/
	* decl.c (decomp_type_table): Use tree_cache_map.
	* init.c (nsdmi_inst): Likewise.
	* pt.c (defarg_ints): Likewise.
	* cp-objcp-common.c (cp_get_debug_type): Likewise.

From-SVN: r254731

1 files changed, 7 insertions, 0 deletions

diff --git a/gcc/tree.h b/gcc/tree.h
index 277aa91..39acffe 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -4858,6 +4858,13 @@ struct tree_decl_map_cache_hasher : ggc_cache_ptr_hash<tree_decl_map>
 #define tree_vec_map_hash tree_decl_map_hash
 #define tree_vec_map_marked_p tree_map_base_marked_p
 
+/* A hash_map of two trees for use with GTY((cache)).  Garbage collection for
+   such a map will not mark keys, and will mark values if the key is already
+   marked.  */
+struct tree_cache_traits
+  : simple_cache_map_traits<default_hash_traits<tree>, tree> { };
+typedef hash_map<tree,tree,tree_cache_traits> tree_cache_map;
+
 /* Initialize the abstract argument list iterator object ITER with the
    arguments from CALL_EXPR node EXP.  */
 static inline void