tejohnson added a comment. In D36850#2990847 <https://reviews.llvm.org/D36850#2990847>, @modimo wrote:
> In D36850#2990771 <https://reviews.llvm.org/D36850#2990771>, @tejohnson wrote: > >> In D36850#2968536 <https://reviews.llvm.org/D36850#2968536>, @modimo wrote: >> >>> In D36850#2964293 <https://reviews.llvm.org/D36850#2964293>, @tejohnson >>> wrote: >>> >>>> Good point on indirect calls. Rather than add a bit to the summary, can >>>> the flags just be set conservatively in any function containing an >>>> indirect call when we build the summaries initially? I think that would >>>> get the same effect. >>> >>> That could have an issue where A calls {indirect, B} and A gets propagated >>> upon from B without knowledge that the indirect call exists. Right now I've >>> got a FunFlags `hasUnknownCall` which marks these as non-propagatable. >> >> Ah, because there isn't a conservative setting of the flag...which raises a >> larger issue (but maybe I am completely missing something) - how do we >> distinguish between the NoUnwind summary flag not being set because we don't >> know yet (in which case we want the propagation from callees), vs because it >> cannot be NoUnwind (because there is a throw in the function)? Do we need to >> have a second flag indicating that a function contains a mayThrow >> instruction (other than calls, which are being handled by the propagation)? > > Only call instructions can throw (what ultimately performs the throw > operation is an opaque call to __cxa_throw()) which simplifies the problem. > If all calls are known, we only need to examine the callees for accurate > propagation. What about the other instruction checks done in Instruction::mayThrow i.e. http://llvm-cs.pcc.me.uk/lib/IR/Instruction.cpp#592? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D36850/new/ https://reviews.llvm.org/D36850 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
