Progress on the Firefox ppc64le JIT

A picture is worth a thousand Wasm opcodes. This is further along than we've gotten on earlier drafts. More soon.

Partial ppc64le JIT available again for Firefox 115ESR

I've been rehabilitating the old ppc64le JIT against more current Firefoxes and there is now available a set of patches you can apply to the current 115ESR. This does not yet include support for Ion or Wasm; the first still has some regressions, and the second has multiple outright crashes. Still, even with just the Baseline Interpreter and Baseline Compiler it is several times faster on benchmarks than the interpreter-only 115. I've included also the relevant LTO-PGO and WebRTC patches so you can just apply the changesets numerically and build. The patches and the needed .mozconfigs for either building an optimized browser or a debug JS shell (should you want to poke around) are in this Github issue.

While this passes everything that is expected to pass, you may still experience issues using it, and you should not consider it supported. Always backup your profile first. But it's now an option for those of you who were using the previous set of patches against 91ESR.

ppc64le JIT now officially landing (again) in DOSBox Staging

Waaaay back when, I wrote up a basic dynamic recompilation JIT for vanilla DOSBox (the most well-known of the DOS-specific emulators, if you've been under a rock for awhile), which increases performance in x86 protected mode by as much as several times. This was an unofficial patch and I just kept it out of the tree, since the 32-bit PowerPC JIT it was based on wasn't part of it either.

Well, little did I know, but the patch got picked up as part of the DOSBox Staging spin six months later and apparently ran fine until an upstream commit broke it. I never noticed because I was happily using my old build, but Trung Lê did and reported it. So I fixed it and added proper support for 4K or 64K page sizes, and it was committed to the source tree today as part of 0.81. If you can't wait, build from source today, or wait for your package manager to pick it up whenever 0.81 gets formally released.

Firefox 117 on POWER

Now that the Talos II is upgraded and tuned up, it's back to development work, starting with (after a TenFourFox patch dump) Firefox 117. Maybe it's just me, but it seems subjectively zippier than 116, even accounting for the cruft that builds up during long browser sessions, and there are some notable developer-facing improvements. As usual, for the long-playing bug 1775202, either put --disable-webrtc in your .mozconfig if you don't need WebRTC, or tweak third_party/libwebrtc/moz.build with the patch from Fx116. The browser otherwise builds and works with a tweaked PGO-LTO patch and the .mozconfigs from Firefox 105.