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

Planned next projects

• PGAOT (Profile-Guided Ahead-of-Time Compilation):
  • Create a baseline asm.js compiler: super-fast codegen but with full static type info
  • Allow individual functions in an asm.js module to choose full or baseline (via "use" pragma on individual functions)
  • Allow Emscripten users to change default (full or baseline), hand-annotate, or do profiling to place pragmas.
• 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 load-time optimizations

• Parse and AOT compile while downloading: bug 1061886
• Move code generation into the parallel compilation tasks: bug 959263
• asm.js parser: Avoid building an intermediate parse tree; type check during recursive descent bug 854061

Possible further throughput optimizations

• Optimize sin/cos: bug 967709
• Use callee-saved registers: bug 985065
• 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
• For asm.js->asm.js calls on x86, pass the return value via xmm register, not fp stack
• Remove branching from double-to-int conversion using signal handler (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

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Credit to John Howard