Matthew Gaudet mgaudet

Shapes: A set of References

A good overview of the high level concept from the Ruby community, which is considering trying to adopt object shapes themselves:
- The Future Shape of Ruby Objects
- https://bugs.ruby-lang.org/issues/18776
The Concrete Comment describing our shapes:
- Shape.h - mozsearch
- PropMap.h - mozsearch
An overview from Mattias Bynens:
- JavaScript engine fundamentals: Shapes and Inline Caches · Mathias Bynens

Remember: Pairs are (ScriptNum, ScopeNum)

// Script 1
// Scope 1
var x = 1;                              // Declared(1) = [x];
function f() // Script 2
{ // Scope 2

Has a Function argument, Called from
FunctionNode* frontend::StandaloneFunctionCompiler<Unit>::parse which has a function argument, called from
static bool CompileStandaloneFunction which has a function argument. Called from
- bool frontend::CompileStandaloneGenerator
- bool frontend::CompileStandaloneAsyncFunction
- bool frontend::CompileStandaloneAsyncGenerator
  - All of the above CompileStandAlones, plus the below CompileStandAloneFunction are called from CreateDynamicFunction: the function is allocated there. The above three are -only- called from CreateDynamicFunction.
bool frontend::CompileStandaloneFunction which has a function argument. Called from

	matthew@ZenTower:~/unified-git$ time git gc
	Enumerating objects: 26048854, done.
	Counting objects: 100% (26048854/26048854), done.
	Delta compression using up to 64 threads
	Compressing objects: 100% (10307736/10307736), done.
	Writing objects: 100% (26048854/26048854), done.
	Total 26048854 (delta 15565600), reused 25346912 (delta 14917729), pack-reused 0
	Enumerating cruft objects: 27, done.
	Traversing cruft objects: 656, done.
	Counting objects: 100% (27/27), done.

	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<title>Div Allocation Timer</title>
	</head>
	<body>
	<h1>Div Allocation Timer</h1>
	<p>Click the button below to allocate 1000000 div elements and measure the time taken.</p>
	<button onclick="measureAllocationTime()">Allocate Divs</button>

	$ ../../../mach run run.js # Interpreter, CacheIR, Baseline, Ion: 34252 (3.5x)
	$ ../../../mach run --no-ion run.js # Interpreter, CacheIR, Baseline: 9887 (2.0x)
	$ ../../../mach run --no-ion --no-baseline --cache-ir-stubs=on run.js # Interpreter, CacheIR: 4890 (6.6x)
	$ ../../../mach run --no-ion --no-baseline --cache-ir-stubs=off run.js # Interpreter: 739

	MOZCONFIG:

	ac_add_options --enable-application=js

	ac_add_options --enable-optimize

	0x2b872bbb5456: testl %edx, %edx ; branchTest32 (the test)
	0x2b872bbb5458: jne 0x2b872bbb546d ; branchTest32 (the jump to true)
	0x2b872bbb545e: movabsq $0x37c1c9d258a0, %rax ; movPtr
	0x2b872bbb5468: jmp 0x2b872bbb5477 ; jump done
	true: 0x2b872bbb546d: movabsq $0x37c1c9d27480, %rax ; movPtr
	done: 0x2b872bbb5477: <unrelated instruction>

	$ java -Xjit:traceIlGen,log=logFile,verbose -version

	#INFO: _______________________________________
	#INFO: Version Information:
	#INFO: JIT Level - 292f272
	#INFO: JVM Level - 20171027_36
	#INFO: GC Level - 292f272
	#INFO:
	#INFO: Processor Information:
	#INFO: Platform Info:X86 Intel P6