drivers: construct driver list at runtime #233
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Relying on linker politeness could fail when compiled with -flto : https://sigrok.org/bugzilla/show_bug.cgi?id=1433 Instead of using a special section that holds a pointer to each of the driver descriptors, use "__attribute__((constructor))" to run a certain function at runtime just before main() entry. That is also before glib init and possibly (unclear) before heap is usable, so it may not be possible to directly build a GArray or GSList. A simple linked-list provides the intermediarey step, and sr_drivers_init() still builds the final driver list via a GArray. This compiler attribute is well-supported by gcc and clang. The SR_REGISTER_DEV_DRIVER_LIST() implementation is also not very elegant, but is a drop-in replacement.
if no drivers were compiled, the for() loop can safely remain.
Each struct sr_dev_driver is writable, but the array of pointers to those structs can be const.
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Relying on linker politeness could fail when compiled with -flto : https://sigrok.org/bugzilla/show_bug.cgi?id=1433
Instead of using a special section that holds a pointer to each of the driver descriptors, use
__attribute__((constructor))to run a certain function at runtime just before main() entry.That is also before glib init and possibly (unclear) before heap is usable, so it may not be possible to directly build a GArray or GSList. A simple linked-list provides the intermediate step, and
sr_drivers_init()still builds the final driver list via a GArray.This compiler attribute is well-supported by gcc and clang.
It would possible to simplify this if struct sr_dev_driver had a 'next' member.
The SR_REGISTER_DEV_DRIVER_LIST() implementation is also not very elegant, but is a drop-in replacement.