On 2016-09-22 9:07 AM, Gijs Kruitbosch wrote: > On 22/09/2016 05:28, Nicholas Nethercote wrote: >> Greetings, >> >> Assertions, such as MOZ_ASSERT, are great. But they only run in debug >> builds. >> >> Release assertions, such as MOZ_RELEASE_ASSERT, run in all builds. >> >> I want to highlight a nice case where converting a normal assertion >> into a release assertion was a win. In bug 1159244 Michael Layzell did >> this in nsTArray::ElementAt(), to implement a form of always-on array >> bounds checking. See >> https://bugzilla.mozilla.org/show_bug.cgi?id=1159244#c55 for >> discussion of how this is finding real bugs in the wild. (As well as >> identifying new bugs, it's also helping understand existing crash >> reports, e.g. see bug 1291082 where the crash signature changed.) >> >> Obviously we can't convert every normal assertion in the codebase into >> a release assertion. But it might be worth thinking about which normal >> assertions are good candidates for conversion. Good candidates include >> any assertion where the consequence of failure is dangerous, e.g. >> might cause memory access violations. >> >> Nick > > Yes please. This + diagnostic assert also helps frontend people who > build and run opt builds (because debug builds are too slow to be > usable, especially when combined with the browser toolbox (JS > debugging)). Right now I miss some of these and then only find out when > the tests that I did run go orange on try and/or inbound/autoland, and > then I have to locally change the relevant C++ so I can test in my opt > build (or resign myself to doing a separate clobber debug build somewhere).
What exact debug configuration is too slow for you? People who want to debug C++ generally turn optimizations off, but for front-end devs, I think building with --enable-debug and --enable-optimize should give you an optimized build with the debug facilities turned on, which should be much faster. Although it is not going to be as fast as a --disable-debug --enable-optimize build, there's a lot of value in Mozilla developers running builds with debug checks turned on, so that we can get good bug reports when an assertion fires when working on a front-end feature, etc. _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
