adding inline caching, inlining and peepholes to JIT-Compiler

[abstraktor]

As part of the VMs seminar, we implemented the following:

• monomorphic inline cache
• method inlining of primitives
• peephole framework with the following peepholes:
  • push push numericOp
  • push popReturn
  • push push numericOp conditionalJumpIfTrue
• disabled global method cache as it should now speedup only rare cases (inline cache should do the job)
• moved primitives to a dictionary of functions
• doing oldPrims featureswitch at launchtime
• jit doesn't generate a switch if the compiled function has no labels
• added some statistics about which {1, 2, 3}-grams are used by tinyBenchmarks (used to find promising peepholes)

Due to rewriting the history a lot for beautification, the commits authors got blurred a bit. We are @abstraktor, @hotzenklotz and @nilos.

[codefrau]

Please put spaces outside the parentheses in control statements (if, for, etc): instead of if(...){ write if (...) {.

[codefrau]

Also, make the generated code look nice. Proper spacing and line breaks help in seeing problems. If the debug flag is enabled, generate useful comments (e.g. which bytecodes were collapsed by peephle optimization).

[codefrau]

Please debug the peephole optimizations with

Squeak.Compiler.comments = true

It will currently generate code like

// 4 <11> peephole-optimized push push numericop
if (typeof temp[7]  === 'number') {stack[++vm.sp] = temp[7] > 0 ? vm.trueObj : vm.falseObj;vm.pc = 7;continue;
}// 5 <> push

stack[++vm.sp] = temp[7];
// 5 <75> push
stack[++vm.sp] = 0;
// 6 <B3> numeric op >
var a = stack[vm.sp - 1], b = stack[vm.sp];
if (typeof a === 'number' && typeof b === 'number') {
   stack[--vm.sp] = a > b ? vm.trueObj : vm.falseObj;
} else { vm.pc = 7; vm.sendSpecial(3); if (context !== vm.activeContext || vm.breakOutOfInterpreter !== false) return bytecodes + 7}

But it does make no sense to check the type of temp[7] twice. I would have expected it to generate something more like

// 4 <11 75 B3> push push numericop > (peephole optimized)
if (typeof temp[7] === 'number') {
    stack[++vm.sp] = temp[7] > 0 ? vm.trueObj : vm.falseObj;
} else {
    stack[++vm.sp] = temp[7];
    stack[++vm.sp] = 0;
    vm.pc = 7; vm.sendSpecial(3); if (context !== vm.activeContext || vm.breakOutOfInterpreter !== false) return bytecodes + 7}
}

Also, in this example (which is from this.vm.findMethod('Set>>findElementOrNil:').compiled), why isn't it optimizing push-push-op-jump? There is a jump immediately following this.

[abstraktor]

ok that was a poor try, next time, we'll do better. Thanks Bert for looking at it. I'm sorry for actually wasting your time here. I could easily have seen some of those on my own ^^

[abstraktor]

@bertfreudenberg I think all your issues should be resolved now. Thanks for your patience. Will you recheck this?

[codefrau]

Will look at this asap, I'm just really busy at the moment.