On Thu, Oct 30, 2008 at 01:39:33PM +0000, Daniel P. Berrange wrote:
A while ago we introduced a libvirt_test.so which is identical to libvirt.so, but without the linker whitelist of symbols. This did impose a little overhead in the build process - it meant we compiled all source files twice.
A future patch will want to compile drivers into individual libraries to allow dlopening, and it occurred to me that if we built some more libtool convenience libraries we could avoid the double compilation.
The trick is that libvirt.la must not have any source files listed against it. It must only be used to link together other convenience libraries. So, I define a while set of libraries
- libvirt_util.la - generic code not related to drivers or libvirt API - libvirt_driver.la - the libvirt public API and driver support code - libvirt_driver_XXXX.la - one for each of qemu, xen, test, remote, openvz, lxc, storage, network
These are all convenience libraries, so libtool will just build a local non-installed, static .a archive.
Now, the actual things we care about
- libvirt.la - links to all of these convenience .la libraries together and adds the libvirt_sym.version script to filter symbols - libvirt_test.la - the same, but with the version script - libvirt_lxc - links to libvirt_util.la and libvirt_driver_lxc.la - virsh - links to libvirt.la
So the end result is that each source file is only ever compiled once, and each library/program just links to the .a files is actually needs.
In principle it's fine, it's equivalent, but it's a bit complex. Maybe this description should go somewhere in the HACKING file too i assume we can still compile with --disable-shared and everything will just build and link fine, just that the .la will be replaced with good old .a and the binaries will have them statically linked in. I we can just double check this, +1 Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/