Javascript:SpiderMonkey:OdinMonkey

Active

• Heap resizing: bug 965880
• Implement SIMD proposal (bug 894105) and incorporate into asm.js (bug 992267)
• Continued SharedArrayBuffer prototyping in SpiderMonkey and Emscripten
• Optimize sin/cos: bug 967709

Planned next projects

• Move code generation into the parallel compilation tasks: bug 959263
• Zero-cost exception handling: bug 1065089
• Optimize calls into (bug 962641), out of (bug 1000632), and between (bug 982036) asm.js modules.
• Remove async-script requirement for asm.js caching:
  • Maybe remove it from QuotaManager: bug 961057
  • More likely, just take (large) script parsing off the main thread.
• Fix asm.js caching browser interop (bug 1047098, bug 1047105

Possible further optimization projects

• General backend optimizations:
  • Use callee-saved registers: bug 985065
  • Enable backtracking allocator: bug 983580
  • Avoid over-recursed check in leaf functions: bug 985130
  • Heap access: bug 986981, bug 870743, bug 897425, bug 915157, bug 983131, bug 865523, bug 984478, bug 1056027
  • Optimize add-with-overflow: bug 1043365
  • Optimize min/max: bug 1060635
• Further improve load-time:
  • Parse and AOT compile while downloading: bug 1061886
  • asm.js parser: Avoid building an intermediate parse tree; type check during recursive descent bug 854061
• Further improve caching:
  • Compress more than just the source in asm.js cache entries
• Improve compile time on pathological functions:
  • Break up super-large functions into disjoint regions that can be regalloc'd and optimized separately
  • Investigate GVN quadratic behavior : bug 845068
• For asm.js->asm.js calls on x86, pass the return value via xmm register, not fp stack
• Extend the asm.js signal handler tricks to:
  • Remove idiv branching
  • Remove double-to-int conversion branching (see also bug 818750)

Possible asm.js extensions that don't require new JS features

• Extend asm.js to allow proper tail calls for all return types and do the tail-call optimization
• Effectively support 'goto' (even computed 'goto') by formalizing a pattern of while+switch that gets compiled as if it was goto
• Extend asm.js to better support dynamically linking asm.js modules (a mutable, callable array argument to asm.js module, like the PLT)
• Add DataView to avoid the alignment mask on asm.js heap accesses (this is mostly a problem of DataView being slow in all browsers)

Proposed future JS features that would be useful to asm.js

• ArrayBuffer.prototype.discard (bug 855669): to allow madvise(DONTNEED)
• Typed Objects: (Typed Objects)
  • This feature comes with float32/uint64/int64 value types, which would be useful as scalar types in asm.js.
  • Formalize Typed Object "class declarations" in asm.js which could make asm.js a target for JVM/CLR/TypeScript (and allow these languages to reuse the builtin JS GC)
• FunctionPromise: bug 854627, or perhaps just make some functions (asm.js, no-free-variables) structured-cloneable
• Add way to programmatically observe whether asm.js validated: bug 952847

Usability improvements

• Print warning on out-of-bounds heap access: bug 879891
• Add about:config option to check for and emit warning on unaligned heap access

Current asm.js spec bugs

https://github.com/dherman/asm.js/issues?state=open

Logo

Credit to John Howard