Re: some question about gc

[Ian Lance Taylor <ian at airs dot com>]

"zouq" <zouqiong@ict.ac.cn> writes:

> in the gt-c-decl.h,
> three functions about lang_decl,
> gt_pch_nx_lang_decl(),gt_ggc_mx_lang_decl, gt_pch_g_9lang_decl(),
> what are the differences between the three functions?

The _nx_ functions fill in the pchw field of ggc_root_tab.  This is used
when saving the data out to a PCH file.  The _mx_ functions fill in
the cb field of gcc_root_tab.  This is used when marking from a root
during garbage collection.  The 9lang functions appear in language
specific header files.

> 2.
> i can find the prefixes in the gengtype.c,
> 
> what are they setting for?
> 
> static const struct write_types_data ggc_wtd =
> {
>   "ggc_m", NULL, "ggc_mark", "ggc_test_and_set_mark", NULL,
>   "GC marker procedures.  "
> };
>                                                                                                                            static
> const
> struct
> write_types_data
> pch_wtd
> =
> {
>   "pch_n", "pch_p", "gt_pch_note_object", "gt_pch_note_object",
>   "gt_pch_note_reorder",
>   "PCH type-walking procedures.  "
> };

PCH means Precompiled Header.  See the docs.

Ian