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In commit 149ce5c263 we introduced the concept of "movable" refs,
which are refs that can be moved in batches, to let us maintain valid ref
lists even when adding refs to blocks of memory that can be realloced (which
is any type containing a vlen which can expand, like names contained within
enum or struct members). Movable refs need a backpointer to the movable
refs dynhash for this dict; since non-movable refs are very common, we tried
to save memory by having a slightly bigger struct for moveable refs with a
backpointer in it, and casting appropriately, indicating which sort of ref
we were dealing with via a flag on the atom.
Unfortunately this doesn't work reliably, because you can perfectly well
have a string ("foo", say) which has both non-movable refs (say, an external
symbol and a variable name) and movable refs (say, a structure member name)
to the same atom. Indicate which struct we're dealing with with an atom
flag and suddenly you're casting a ctf_str_atom_ref to a
ctf_str_atom_ref_movable (which is bigger) and dereferencing random memory
off the end of it and interpreting it as a backpointer to the movable refs
dynhash. This is unlikely to work well.
So bite the bullet and split refs into two separate lists, one for movable
refs, one for immovable refs. It means some annoying code duplication, but
there's not very much of it, and it means we can keep the movable refs
hashtab (which in turn means we don't have to do linear searches to find all
relevant refs when moving refs, which in turn means that
structure/union/enum member additions remain amortized O(n) time, not
O(n^2).
Callers can now purge movable and non-movable refs independently of each
other. We don't use this yet, but a use is coming.
libctf/
* ctf-impl.h (CTF_STR_ATOM_MOVABLE): Delete.
(struct ctf_str_atom) [csa_movable_refs]: New.
(struct ctf_dict): Adjust comment.
(ctf_str_purge_refs): Add MOVABLE arg.
* ctf-string.c (ctf_str_purge_movable_atom_refs): Split out of...
(ctf_str_purge_atom_refs): ... this.
(ctf_str_free_atom): Call it.
(ctf_str_purge_one_atom_refs): Likewise.
(aref_create): Adjust accordingly.
(ctf_str_move_refs): Likewise.
(ctf_str_remove_ref): Remove movable refs too, including
deleting the ref from ctf_str_movable_refs.
(ctf_str_purge_refs): Add MOVABLE arg.
(ctf_str_update_refs): Update movable refs.
(ctf_str_write_strtab): Check, and purge, movable refs.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.