On Wed, May 30, 2018 at 8:06 AM, Dave Townsend <dtowns...@mozilla.com> wrote: > On Tue, May 29, 2018 at 10:03 PM Jeff Gilbert <jgilb...@mozilla.com> wrote: >> I get that, but it reminds me of the reasons people give for "our >> website works best in $browser". > > I was concerned by this too but found myself swayed by the arguments in > https://blog.mozilla.org/nfroyd/2018/05/29/when-implementation-monoculture-right-thing/and > in particular the first comment there.
Indeed, the first comment there (by roc) gets to the point. Additionally, the reasons for not supporting multiple browsers tend to be closer to the "didn't bother" kind whereas we're looking to get a substantial benefit from clang that MSVC and GCC don't offer to us but clang likely will: Cross-language inlining across code compiled with clang and code compiled with rustc. To the extent Mozilla runs the compiler, it makes sense to go for the Open Source choice that allows us to deliver better on "performance as a feature". We still have at least one static analysis running on GCC, so I wouldn't expect GCC-compatibility to be dropped even if the app wouldn't be "best compiled with" GCC. The Linux distro case is trickier than Mozilla's compiler choice. For CPUs that are tier-3 for Mozilla, we already tolerate less great performance attributes in order to enable availability, so distros keeping using GCC for tier-3 probably isn't a problem. x86_64 could be a problem, though. If Firefox's performance becomes significantly dependent on having cross-language inlining, and I expect it will, having a substantial portion of the user base run without it while thinking they have a top-tier build could be bad. I hope we can get x86_64 Linux distros to track our compiler configuration closely. I do feel bad for the GCC devs, but it's worth noting that this is a result of a deliberate decision not to modularize GCC for licensing strategy reasons while LLVM has been designed as a module, demand for which has had solid technical reasons. The modularity meant it made more sense to build rustc on LLVM than on GCC and now that technical design leads to better synergy with clang. -- Henri Sivonen hsivo...@hsivonen.fi https://hsivonen.fi/ _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
