strcmp() by performing path name length comparison first. In the test
with Mozilla, the number was reduced to 1068 from 7182 (yes, we saved
6114 strcmp()!).
There are several optimizations here:
1) Objects on _rtld_list_main do not participate in the DAG structures
at all. This is okay because all symbols must be resolvable at
link/load time, and _rtld_list_main is always searched first, so
any references from those objects must necessarily be resolved to
other objects on _rtld_list_main.
(Making this work completely required setting obj->main a bit
earlier; hence the RTLD_MAIN hack.)
2) Objects on _rtld_list_main are not put on _rtld_list_global,
preventing an extra search.
3) A bit is used to keep track of whether an object is on
_rtld_list_global, so we don't have to do a silly linear search.
4) A small attempt is made to prevent objects being put on the DAG
lists multiple times (using a silly linear search).
The sum of this appears to be a ~10% (.3s) reduction in Mozilla's
startup time on my 800MHz box.
Also, make sure _rtld_objmain->path is always set, just to make the
debug output nicer.
* Rename _rtld_find_library() to _rtld_load_library(). It now calls
_rtld_load_object() if necessary to actually load the object, rather
than having the caller do it. To do this, it also takes the `mode'
argument that gets passed to _rtld_load_object().
* On a related note, remove _rtld_check_library(), and instead call
_rtld_load_object() to instead try actually loading the object. We
save two extra namei's and a bunch of redundant work (almost
literally the same code) this way.
* In _rtld_map_object(), mmap(2) the first page read-only, rather than
read(2)ing it.
* In _rtld_symlook_obj(), compare the *second* character of the symbol
name before calling strcmp(). (This first character is too
frequently `_', and turns out to not be helpful, in libc.)
* Also in _rtld_symlook_obj(), remove the bogus STT_FUNC special case
-- this also allows removing the `in_plt' argument to
_rtld_symlook_list() and _rtld_symlook_obj().
Also:
* In _rtld_obj_from_addr(), rather than trying to look up `_end' in
the each object, instead use obj->mapsize as the upper bound.
executable that uses the library on that line has the rather cryptic
"sysctl" printed when it starts executing.
Switch to (_PATH_LD_HINTS": unknown sysctl for %s", name);
Discovered after someone copied /etc from an i386 to a sparc64 box.
- implement SIMPLEQ_REMOVE(head, elm, type, field). whilst it's O(n),
this mirrors the functionality of SLIST_REMOVE() (the other
singly-linked list type) and FreeBSD's STAILQ_REMOVE()
- remove the unnecessary elm arg from SIMPLEQ_REMOVE_HEAD().
this mirrors the functionality of SLIST_REMOVE_HEAD() (the other
singly-linked list type) and FreeBSD's STAILQ_REMOVE_HEAD()
- remove notes about SIMPLEQ not supporting arbitrary element removal
- use SIMPLEQ_FOREACH() instead of home-grown for loops
- use SIMPLEQ_EMPTY() appropriately
- use SIMPLEQ_*() instead of accessing sqh_first,sqh_last,sqe_next directly
- reorder manual page; be consistent about how the types are listed
- other minor cleanups
kit, then hacked on by Matt Thomas <matt@3am-software.com>, then by me (to
make it work with new versions of the toolchain, etc.). This runs, but it's
in serious need of cleaning and/or a fair bit of reworking. See the README
file for more information, and a list of things to do.
christos