[PATCH] New lang hook

[PATCH] New lang hook

https://gcc.gnu.org/ml/gcc-patches/2017-11/msg01340.html
	PR c++/82836
	PR c++/82737
	* tree.h (COPY_DECL_RTL): Rename parms for clarity.
	(SET_DECL_ASSEMBLER_NAME): Forward to
	overwrite_decl_assembler_name.
	(COPY_DECL_ASSEMBLER_NAME): Rename parms for clarity.
	(overwrite_decl_assembler_name): Declare.
	* tree.c (overwrite_decl_assembler_name): New.
	* langhooks-def.h (lhd_overwrite_decl_assembler_name): Declare.
	(LANG_HOOKS_OVERWRITE_DECL_ASSEMBLER_NAME): Provide default.
	(LANG_HOOKS_INITIALIZER): Add it.
	* langhooks.h (struct lang_hooks): Add overwrite_decl_assembler_name.
	* langhooks.c (lhd_set_decl_assembler_name): Use
	SET_DECL_ASSEMBLER_NAME.
	(lhd_overwrite_decl_assembler_name): Default implementation.

	PR c++/82836
	PR c++/82737
	* cp-objcp-common.h (LANG_HOOKS_OVERWRITE_DECL_ASSEMBLER_NAME):
	Override.
	* cp-tree.h (overwrite_mangling): Declare.
	* decl2.c (struct mangled_decl_hash): Entries are deletable.
	(overwrite_mangling): New.

	PR c++/82836
	PR c++/82737
	* g++.dg/pr82836.C: New.

From-SVN: r254823