On 05/04/18 16:50, Jiong Wang wrote: > On 03/04/2018 02:08, Alexei Starovoitov wrote: >> Combining subprog pass with do_check is going into opposite direction >> of this long term work. Divide and conquer. Combining more things into >> do_check is the opposite of this programming principle. > > Agree. And for the redundant insn traversal issue in check_subprogs that > Edward trying to fix, I am thinking we could do it by utilizing the > existing DFS traversal in check_cfg. > > The current DFS probably could be improved into an generic instruction > information collection pass. <snip> > And if we want to build basic-block later, we could just call a new add_bb > (similar as add_subprog) for jump targets etc. (some of those places are > actually STATE_LIST_MARK_JMPTARGET if we separate STATE_LIST_MARK as > STATE_LIST_MARK_JMPTARGET and STATE_LIST_MARK_HEURISTIC). > > Regards, > Jiong > This is broadly similar to my medium-term plan, except that I would use the Kahn's-algorithm style tsort rather than the depth-first tsort algorithm used by current check_cfg. * chop up prog into functions and bbs, incidentally placing S_L_Ms * create control flow graph similar to my function call graph * tsort it to detect loops, similar to how my check_max_stack_depth() implementation detects recursion.
-Ed
