239290 2022-04-13 11:50:18 -0700 Misc compiler warnings, April 2022 edition 2022-04-19 10:20:20 -0700 1 1 1 Unclassified WebKit WebKit Misc. WebKit Nightly Build PC Linux RESOLVED FIXED InRadar P2 Normal --- 1 mcatanzaro webkit-unassigned mcatanzaro webkit-bug-importer ysuzuki oldest_to_newest 1861190 0 mcatanzaro 2022-04-13 11:50:18 -0700 Misc compiler warnings, April 2022 edition I'm starting to get tired of -Wreturn-type.... 1861214 1 mcatanzaro 2022-04-13 12:21:03 -0700 https://github.com/WebKit/WebKit/pull/282 1861301 2 ews-feeder 2022-04-13 15:56:15 -0700 Committed r292840 (249613@main): <https://commits.webkit.org/249613@main> Reviewed commits have been landed. Closing PR #282 and removing active labels. 1861302 3 webkit-bug-importer 2022-04-13 15:57:15 -0700 <rdar://problem/91720326> 1862590 4 ysuzuki 2022-04-19 09:39:59 -0700 Please do not attach RELEASE_ASSERT_NOT_REACHED here. Some of them are super hot critical function, and it hurts our performance. Use 269IGNORE_RETURN_TYPE_WARNINGS_BEGIN 1862593 5 ysuzuki 2022-04-19 09:45:31 -0700 Committed r293018 (249757@trunk): <https://commits.webkit.org/249757@trunk> 1862601 6 mcatanzaro 2022-04-19 09:59:52 -0700 ack, thanks for catching it! How scary. :( It will happen again in the future, though, because I can't know where these areas may be, and we keep introducing more and more return type warnings. These make up probably >50% of the GCC warnings that I deal with. One option is to give up and build with -Wno-return-type, because fixing up switch statements is getting pretty old. But sadly, it does seem like a useful warning except for this pattern with switch statements, so I'm a bit hesitant to do that. 1862605 7 ysuzuki 2022-04-19 10:02:59 -0700 (In reply to Michael Catanzaro from comment #6) > ack, thanks for catching it! How scary. :( > > It will happen again in the future, though, because I can't know where these > areas may be, and we keep introducing more and more return type warnings. > These make up probably >50% of the GCC warnings that I deal with. > > One option is to give up and build with -Wno-return-type, because fixing up > switch statements is getting pretty old. But sadly, it does seem like a > useful warning except for this pattern with switch statements, so I'm a bit > hesitant to do that. Can GCC have a mechanism like this? I think it can suppress most of false positives. 1. emitting this warning for normal enum case 2. not emitting this for strongly scoped enum when switch handles all scoped enums 1862608 8 mcatanzaro 2022-04-19 10:09:10 -0700 GCC does have many options (-Wswitch, -Wswitch-default, and -Wswitch-enum) to get exactly your preferred warnings for missing switch cases, but -Wreturn-type is orthogonal to those. 1862613 9 mcatanzaro 2022-04-19 10:15:30 -0700 Did some searching... it seems C++23 has a solution for this, std::unreachable(): https://en.cppreference.com/w/cpp/utility/unreachable In the meantime, we could add a WTF_UNREACHABLE() macro fairly easily, which could replace most use of RELEASE_ASSERT_NOT_REACHED() after switch statements that are intended to always return. Hopefully that would allow us to avoid the performance hit in these locations? Then we wouldn't have to worry about this happening again. (I know it takes you ages to track it down performance regressions....) 1862616 10 mcatanzaro 2022-04-19 10:20:20 -0700 I see we already have UNREACHABLE_FOR_PLATFORM in Assertions.h, but it just calls RELEASE_ASSERT_NOT_REACHED() with a warning not to change that. <_<