Created attachment 608580 [details, diff] Add USE=jit to www-client/firefox-68-4-2 Mozilla folks say that the --disable-ion options does it, and I can confirm that it indeed makes Firefox slow as all hell. This should add another layer to CPU bug mitigation, by preventing bad js from being directly executed on CPU. But I have not done a detailed analysis of it. Relevant preferences options, have not tested if they do what they say they do: pref("javascript.options.baselinejit", false); // This should be enough pref("javascript.options.ion", false); pref("javascript.options.wasm_baselinejit", false); pref("javascript.options.wasm_ionjit", false);
You are welcome to use EXTRA_ECONF to disable jit yourself, I am not interested in supporting this configuration in Gentoo.