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Applications and Porting / [DEV] JIT support for Firefox
« on: April 22, 2026, 10:59:24 pm »
Firstly, all credits go to @ClassicHasClass for his great JIT support work for the v86 Firefox (basically baseline JIT is fully working). He had submitted the patches against upstream at https://bugzilla.mozilla.org/show_bug.cgi?id=1860412 but unfortunately the patch has become stale and no longer work with post-140ESR codebase.
So after spending 3 weeks with help from few people in the PPC community and help of AI agents to track down errors pattern (lacking of tooling like rr-debugger made the work super hard - at one stage I was resolving to all sort of blind hypothesis and nearly gave up), I have successfully revived and fixed number of bugs of the original JIT codes. Please check out https://github.com/runlevel5/firefox/pull/1 to all members here for reviewing.
TL;DR; LE path for POWER8 and POWER9 is fully implemented (including ION JIT, WASM SIMD, JSPI and Simulator). The BE path is still in progress atm. Please give JIT work a go and let me know if you happen to find any bug. I have tried my best to hand test and ran many stress test / benchmarks and have addressed quite a number of edge cases.
So what's next? Trying to get it polished as much as possible then get it upstreamed (for release 153 - why? new ESR would be branched off this version) or simply try to get the patch accepted in downstream sources like Fedora, Debian/Ubuntu.
So after spending 3 weeks with help from few people in the PPC community and help of AI agents to track down errors pattern (lacking of tooling like rr-debugger made the work super hard - at one stage I was resolving to all sort of blind hypothesis and nearly gave up), I have successfully revived and fixed number of bugs of the original JIT codes. Please check out https://github.com/runlevel5/firefox/pull/1 to all members here for reviewing.
TL;DR; LE path for POWER8 and POWER9 is fully implemented (including ION JIT, WASM SIMD, JSPI and Simulator). The BE path is still in progress atm. Please give JIT work a go and let me know if you happen to find any bug. I have tried my best to hand test and ran many stress test / benchmarks and have addressed quite a number of edge cases.
So what's next? Trying to get it polished as much as possible then get it upstreamed (for release 153 - why? new ESR would be branched off this version) or simply try to get the patch accepted in downstream sources like Fedora, Debian/Ubuntu.
