On Thu, May 5, 2016 at 9:26 PM, Gregory Szorc <g...@mozilla.com> wrote:
> There is a compiler bug in VS2015 that results in SSE instructions being > emitted when they shouldn't be. Since Firefox still needs to remain > compatible with ancient hardware that doesn't support SSE, this is causing > crashes on Firefox built with VS2015 (see bug 1265615). > > The good news is glandium found a pretty minimal reproduce case and > reported the bug to Microsoft. > > The bad news is the issue still reproduces in the latest pre-release > version of the Visual C++ toolchain. > > The worse news is we'll have to revert to building Firefox 48 (current > Aurora) and 49 (current central) with VS2013. Bugs 1270664 and 1270714 > track. Aurora will likely land soon. Central might take a few days, as I > believe VS2013 is a bit broken on central at the moment. > We have a change in plans. bsmedberg says we can require SSE. So that means the VS2015 bug emitting SSE instructions isn't an issue. But we need to teach the updater to advertise CPU features in the Firefox version before we drop SSE so we don't update users to a binary that won't work. Since Firefox 48/Aurora is currently using VS2015, that would mean teaching Firefox 47/Beta new tricks. Since we're already in the middle of the Beta cycle and there is no major user benefit to shipping VS2015 builds at this time, we're going to revert to VS2013 on Firefox 48/Aurora and build the updater support into Firefox 48/Aurora. Firefox 49/Nightly will continue to build with VS2015 and will be the first Firefox version to require SSE. Bug 1271755 is our tracker for requiring SSE to run Firefox. _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
