Virtual machine and javascript engine

Virtual Machine & JavaScript Engine @nwind

(HLL) Virtual Machine

Take the red pillI will show you the rabbit hole.

Virtual Machine history• pascal 1970• smalltalk 1980• self 1986• python 1991• java 1995• javascript 1995

The Smalltalk demonstration showed three amazing features. Onewas how computers could be networked; the second was howobject-oriented programming worked. But Jobs and his team paidlittle attention to these attributes because they were so amazed bythe third feature, ...

How Virtual Machine Work?• Parser• Intermediate Representation (IR)• Interpreter• Garbage Collection• Optimization

Parser• Tokenize• AST

Tokenize identiﬁer numberkeyword var foo = 10; semicolon space equal

AST AssignVariable foo Constant 10

{ AST demo (Esprima) "type": "Program", "body": [ { "type": "VariableDeclaration", "declarations": [ { "id": { "type": "Identifier", "name": "foo" }, "init": { "type": "BinaryExpression", var foo = bar + 1; "operator": "+", "left": { "type": "Identifier", "name": "bar" }, "right": { "type": "Literal", "value": 1 } } } ], "kind": "var" }} ] http://esprima.org/demo/parse.html

Intermediate Representation• Bytecode• Stack vs. register

Bytecode (SpiderMonkey) 00000: deffun 0 null 00005: nop 00006: callvar 0 00009: int8 2function foo(bar) { 00011: call 1 return bar + 1; 00014: pop} 00015: stopfoo(2); foo: 00020: getarg 0 00023: one 00024: add 00025: return 00026: stop

Bytecode (JSC) 8 m_instructions; 168 bytes at 0x7fc1ba3070e0; 1 parameter(s); 10 callee register(s) [ 0] enter [ 1] mov! ! r0, undefined(@k0) [ 4] get_global_var! r1, 5 [ 7] mov! ! r2, undefined(@k0) [ 10] mov! ! r3, 2(@k1) [ 13] call!! r1, 2, 10function foo(bar) { [ 17] op_call_put_result! ! r0 return bar + 1; [ 19] end! ! r0} Constants: k0 = undefinedfoo(2); k1 = 2 3 m_instructions; 64 bytes at 0x7fc1ba306e80; 2 parameter(s); 1 callee register(s) [ 0] enter [ 1] add! ! r0, r-7, 1(@k0) [ 6] ret! ! r0 Constants: k0 = 1 End: 3

Stack vs. register• Stack • JVM, .NET, php, python, Old JavaScript engine• Register • Lua, Dalvik, All modern JavaScript engine • Smaller, Faster (about 30%) • RISC

Stack vs. register local a,t,i 1: PUSHNIL 3 a=a+i 2: GETLOCAL 0 ; a 3: GETLOCAL 2 ; i 4: ADDlocal a,t,i 1: LOADNIL 0 2 0 5: SETLOCAL 0 ; aa=a+i 2: ADD 0 0 2 a=a+1 6: SETLOCAL 0 ; aa=a+1 3: ADD 0 0 250 ; a 7: ADDI 1a=t[i] 4: GETTABLE 0 1 2 8: SETLOCAL 0 ; a a=t[i] 9: GETLOCAL 1 ; t 10: GETINDEXED 2 ; i 11: SETLOCAL 0 ; a

Interpreter• Switch statement• Direct threading, Indirect threading, Token threading ...

Switch statementwhile (true) {! switch (opcode) { mov %edx,0xffffffffffffffe4(%rbp)! ! case ADD: cmpl $0x1,0xffffffffffffffe4(%rbp)! ! ! ... je 6e <interpret+0x6e>! ! ! break; cmpl $0x1,0xffffffffffffffe4(%rbp)! ! case SUB: jb 4a <interpret+0x4a>! ! ! ... cmpl $0x2,0xffffffffffffffe4(%rbp)! ! ! break; je 93 <interpret+0x93> ... jmp 22 <interpret+0x22>! } ...}

Direct threadingtypedef void *Inst; mov 0xffffffffffffffe8(%rbp),%rdxInst program[] = { &&ADD, &&SUB }; lea 0xffffffffffffffe8(%rbp),%raxInst *ip = program; addq $0x8,(%rax)goto *ip++; mov %rdx,0xffffffffffffffd8(%rbp) jmpq *0xffffffffffffffd8(%rbp)ADD: ... ADD: goto *ip++; ... mov 0xffffffffffffffe8(%rbp),%rdxSUB: lea 0xffffffffffffffe8(%rbp),%rax ... addq $0x8,(%rax) goto *ip++; mov %rdx,0xffffffffffffffd8(%rbp) jmp 2c <interpreter+0x2c> http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html

Garbage Collection• Reference counting (php, python ...), smart pointer• Tracing • Stop the world • Copying, Mark-and-sweep, Mark-and-compact • Generational GC • Precise vs. conservative

Precise vs. conservative• Conservative • If it looks like a pointer, treat it as a pointer • Might have memory leak • Cant’ move object, have memory fragmentation• Precise • Indirectly vs. Directly reference

It is time for the DARK Magic

Optimization Magic• Interpreter optimization• Compiler optimization• JIT• Type inference• Hidden Type• Method inline, PICs

Interpreter optimization

Switch work ineﬃcient, Why?

CPU Pipeline• Fetch, Decode, Execute, Write-back• Branch prediction

http://en.wikipedia.org/wiki/File:Pipeline,_4_stage.svg

Solution: Inline ThreadingICONST_1_START: *sp++ = 1;ICONST_1_END: goto **(pc++);INEG_START: sp[-1] = -sp[-1];INEG_END: goto **(pc++);DISPATCH_START: goto **(pc++);DISPATCH_END: ;size_t iconst_size = (&&ICONST_1_END - &&ICONST_1_START);size_t ineg_size = (&&INEG_END - &&INEG_START);size_t dispatch_size = (&&DISPATCH_END - &&DISPATCH_START);void *buf = malloc(iconst_size + ineg_size + dispatch_size);void *current = buf;memcpy(current, &&ICONST_START, iconst_size); current += iconst_size;memcpy(current, &&INEG_START, ineg_size); current += ineg_size;memcpy(current, &&DISPATCH_START, dispatch_size);...goto **buf; Interpreter? JIT!

Compiler optimization

Compiler optimization• SSA• Data-ﬂow• Control-ﬂow• Loop• ...

What a JVM can do...compiler tactics language-specific techniques loop transformations delayed compilation class hierarchy analysis loop unrolling Tiered compilation devirtualization loop peeling on-stack replacement symbolic constant propagation safepoint elimination delayed reoptimization autobox elimination iteration range splitting program dependence graph representation escape analysis range check elimination static single assignment representation lock elision loop vectorizationproof-based techniques lock fusion global code shaping exact type inference de-reflection inlining (graph integration) memory value inference speculative (profile-based) techniques global code motion memory value tracking optimistic nullness assertions heat-based code layout constant folding optimistic type assertions switch balancing reassociation optimistic type strengthening throw inlining operator strength reduction optimistic array length strengthening control flow graph transformation null check elimination untaken branch pruning local code scheduling type test strength reduction optimistic N-morphic inlining local code bundling type test elimination branch frequency prediction delay slot filling algebraic simplification call frequency prediction graph-coloring register allocation common subexpression elimination memory and placement transformation linear scan register allocation integer range typing expression hoisting live range splittingflow-sensitive rewrites expression sinking copy coalescing conditional constant propagation redundant store elimination constant splitting dominating test detection adjacent store fusion copy removal flow-carried type narrowing card-mark elimination address mode matching dead code elimination merge-point splitting instruction peepholing DFA-based code generatorhttp://www.oracle.com/us/technologies/java/java7-renaissance-vm-428200.pdf

Just-In-Time (JIT)

JIT• Method JIT, Trace JIT, Regular expression JIT• Code generation• Register allocation

How JIT work?• mmap/new/malloc (mprotect)• generate native code• c cast/reinterpret_cast• call the function

Trampoline (JSC x86) asm ( ".textn" ".globl " SYMBOL_STRING(ctiTrampoline) "n"// Execute the code! HIDE_SYMBOL(ctiTrampoline) "n"inline JSValue execute(RegisterFile* registerFile, SYMBOL_STRING(ctiTrampoline) ":" "n" CallFrame* callFrame, "pushl %ebp" "n" JSGlobalData* globalData) "movl %esp, %ebp" "n"{ "pushl %esi" "n" JSValue result = JSValue::decode( "pushl %edi" "n" ctiTrampoline( "pushl %ebx" "n" m_ref.m_code.executableAddress(), "subl $0x3c, %esp" "n" registerFile, "movl $512, %esi" "n" callFrame, "movl 0x58(%esp), %edi" "n" 0, "call *0x50(%esp)" "n" Profiler::enabledProfilerReference(), "addl $0x3c, %esp" "n" globalData)); "popl %ebx" "n" return globalData->exception ? jsNull() : result; "popl %edi" "n"} "popl %esi" "n" "popl %ebp" "n" "ret" "n" );

Register allocation• Linear scan• Graph coloring

Code generation• Pipelining• SIMD (SSE2, SSE3 ...)• Debug

Type inference

Property access

“foo.bar”

foo.bar in C00001f63!movl! %ecx,0x04(%edx)

__ZN2v88internal7HashMap6LookupEPvjb:00000338! pushl!%ebp00000339! pushl!%ebx0000033a! pushl!%edi0000033b!0000033c!0000033f!00000343!00000346!00000349! pushl!%esi subl! $0x0c,%esp movl! 0x20(%esp),%esi movl! 0x08(%esi),%eax movl! 0x0c(%esi),%ecx imull!$0x0c,%ecx,%edi foo.bar in JavaScript0000034c! leal! 0xff(%ecx),%ecx0000034f! addl! %eax,%edi00000351! movl! 0x28(%esp),%ebx00000355! andl! %ebx,%ecx00000357! imull!$0x0c,%ecx,%ebp0000035a! addl! %eax,%ebp0000035c! jmp! 0x0000036a0000035e! nop00000360! addl! $0x0c,%ebp00000363! cmpl! %edi,%ebp00000365! jb! 0x0000036a00000367! movl! 0x08(%esi),%ebp0000036a!0000036d!0000036f! movl! 0x00(%ebp),%eax testl!%eax,%eax je! 0x0000038b __ZN2v88internal7HashMap6LookupEPvjb00000371! cmpl! %ebx,0x08(%ebp)00000374! jne! 0x0000036000000376! movl! %eax,0x04(%esp)0000037a!0000037e!00000381! movl! 0x24(%esp),%eax movl! %eax,(%esp) call! *0x04(%esi) means:00000384! testb!%al,%al00000386! je! 0x0000036000000388! movl! 0x00(%ebp),%eax0000038b!0000038d!00000393! testl!%eax,%eax jne! 0x00000418 cmpb! $0x00,0x2c(%esp) v8::internal::HashMap::Lookup(void*, unsigned int, bool)00000398! jne! 0x0000039e0000039a! xorl! %ebp,%ebp0000039c! jmp! 0x000004180000039e! movl! 0x24(%esp),%eax000003a2! movl! %eax,0x00(%ebp)000003a5! movl! $0x00000000,0x04(%ebp)000003ac! movl! %ebx,0x08(%ebp)000003af! movl! 0x10(%esi),%eax000003b2! leal! 0x01(%eax),%ecx000003b5! movl! %ecx,0x10(%esi)000003b8! shrl! $0x02,%ecx000003bb! leal! 0x01(%ecx,%eax),%eax... 27 lines more

How to optimize?

Hidden Type add property x then add property y http://code.google.com/apis/v8/design.html

But nothing is perfect

one secret in V8 hidden class 20x times slower! http://jsperf.com/test-v8-delete

in Figure 5, reads are far more common than writes: over all Write_indx roughly comparable to me 1. Write_prop Read_prop 0.8 traces the proportion of reads to writes is 6 to 1. Deletes comprise Write_hash Read_hash class-based languages, suc Write_indx Read_indx only .1% of all events. That graph further breaks reads, writes Write_prop Read_prop Delet_prop ric discussed in [23]. Studi But property are rarely deleted and deletes into various speciﬁc types; prop Delet_hash to accesses refers 0.8 Write_hash Read_hash DIT of 8 and a median of 0.6 Write_indx Read_indx Delet_indx Write_prop Read_prop Delet_prop Define and maximum of 10. Figu Write_hash Read_hash Write_indx Read_indx Delet_hash Delet_indx Create Call median prototype chain le 0.6 10 Write_prop Read_prop Delet_prop Define Throw chain length 1, the minimu 0.4 Write_hash Read_hash Delet_hash Create Catch Write_indx Read_indx Delet_indx Call have at least one prototyp Read_prop Define Object.prototype. The m 1.0 Delet_prop Throw 9 0.4 Read_hash Delet_hash Create Catch is 10. The majority of site 0.2 Read_indx Delet_indx Call Delet_prop Define Throw Delet_hash Create Catch reuse, but this is possibly 8 0.8 Delet_indx Call to achieve code reuse in J 0.2 Define Throw 0.0 Create Catch sures directly into a ﬁeld o prototypes have similar in 7 Call 280s Fbok Apme Bing Blog Digg Flkr Gmai Gmap Lvly Twit Wiki Goog IShk Word Ebay YTub All* Prototype chain length Throw 0.6 0.4 Flkr 0.0 Catch Only 0.1% delete 5.4 Object Kinds 280s Fbok Gmai Gmap Lvly Twit Wiki Apme Bing Blog Digg Goog IShk Word Ebay YTub All* 6 280S BING BLOG EBAY FBOK DIGG FLKR GMIL GMAP GOGL ISHK LIVE MECM TWIT ALL* WIKI WORD YTUB Figure 7 breaks down the Fbok Bing Blog Digg Flkr Gmai Gmap Lvly Twit Wiki Goog IShk Word Ebay YTub All* into a number of categorie 5 built-in data types: dates (DFbok Gmap Lvly Twit Wiki Flkr Gmai Goog IShk Word Ebay YTub All* 0.2 ument and layout objects 4 rors. The remaining objec Lvly Twit Wiki Goog IShk Word Ebay 0.0 YTub All* mous objects, instances, fu jects are constructed with a 3 Figure 5. Instruction mix. The per-site proportion of read, write, while instances are constr 280S BING BLOG EBAY FBOK LIVE ALL* DIGG FLKR GMIL GMAP GOGL ISHK MECM TWIT WIKI WORD YTUB delete, call instructions (averaged over multiple traces). A function object is creat 2 An Analysis of the Dynamic Behavior ofthe interpreter a uated by JavaScript Programs

Optimize method call

bar can be anythingfunction foo(bar) { return bar.pro();}

adaptive optimization for self

Polymorphic inline cache

Tagged pointer

Tagged pointertypedef union { void *p; double d; long l;} Value;typedef struct { unsigned char type; sizeof(a)?? Value value;} Object; if everything is object, it will be too much overhead for small integerObject a;

Tagged pointer In almost all system, the pointer address will be aligned (4 or 8 bytes)“The address of a block returned by malloc or realloc in the GNU system isalways a multiple of eight (or sixteen on 64-bit systems). ” http://www.gnu.org/s/libc/manual/html_node/Aligned-Memory-Blocks.html

Tagged pointerExample: 0xc00ab958 the pointer’s last 2 or 3 bits must be 0 1 0 0 0 1 0 0 1 8 9 Pointer Small Number

How about double?

NaN-tagging (JSC 64 bit)In 64 bit system, we can only use 48 bits, that means it will have 16 bits are 0 * The top 16-bits denote the type of the encoded JSValue: * * Pointer { 0000:PPPP:PPPP:PPPP * / 0001:****:****:**** * Double { ... * FFFE:****:****:**** * Integer { FFFF:0000:IIII:IIII

V8• Lars Bak• Hidden Class, PICs• Built-in objects written in JavaScript• Crankshaft• Precise generation GC

Lars Bak• implement VM since 1988• Beta• Self• HotSpot

Source code Native Code High-Level IR Low-Level IR Opt Native Code } Crankshaft

Hotspot client compiler

Crankshaft• Proﬁling• Compiler optimization• On-stack replacement• Deoptimize

High-Level IR (Hydrogen) • function inline • type inference • stack check elimination • loop-invariant code motion • common subexpression elimination • ...http://wingolog.org/archives/2011/08/02/a-closer-look-at-crankshaft-v8s-optimizing-compiler

Low-Level IR (Lithium) • linear-scan register allocator • code generate • lazy deoptimizationhttp://wingolog.org/archives/2011/09/05/from-ssa-to-native-code-v8s-lithium-language

Built-in objects written in JSfunction ArraySort(comparefn) { if (IS_NULL_OR_UNDEFINED(this) && !IS_UNDETECTABLE(this)) { throw MakeTypeError("called_on_null_or_undefined", ["Array.prototype.sort"]); } // In-place QuickSort algorithm. // For short (length <= 22) arrays, insertion sort is used for efficiency. if (!IS_SPEC_FUNCTION(comparefn)) { comparefn = function (x, y) { if (x === y) return 0; if (%_IsSmi(x) && %_IsSmi(y)) { return %SmiLexicographicCompare(x, y); } x = ToString(x); y = ToString(y); if (x == y) return 0; else return x < y ? -1 : 1; }; } ... v8/src/array.js

V8 performance

Can V8 be faster?

Dart• Clear syntax, Optional types, Libraries• Performance• Can compile to JavaScript• But IE, WebKit and Mozilla rejected it• What do you think? • My thought: Will XML replace HTML? No, but thanks Google, for push the web forward

Embed V8

Expose Functionv8::Handle<v8::Value> Print(const v8::Arguments& args) { for (int i = 0; i < args.Length(); i++) { v8::HandleScope handle_scope; v8::String::Utf8Value str(args[i]); const char* cstr = ToCString(str); printf("%s", cstr); } return v8::Undefined();}v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New();global->Set(v8::String::New("print"), v8::FunctionTemplate::New(Print));

Node.JS• Pros • Cons • Async • Lack of great libraries • One language for everything • ES5 code hard to maintain • Faster than PHP, Python • Still too youth • Community

JavaScriptCore (Nitro)

Where it comes from?

1997 Macworld

“Apple has decided to make Internet Explorer it’s default browseron macintosh.”“Since we believe in choice. We going to be shipping other InternetBrowser...” Steve Jobs

JavaScriptCore History• 2001 KJS (kde-2.2) • 2008 SquirrelFish Extreme • Bison • PICs • AST interpreter • method JIT• 2008 SquirrelFish • regular expression JIT • Bytecode(Register) • DFG JIT (March 2011) • Direct threading

InterpreterAST Bytecode Method JIT SSA DFG JIT

SipderMonkey

Monkey• SpiderMonkey • JägerMonkey • Written by Brendan Eich • PICs • interpreter • method JIT (from JSC)• TraceMonkey • IonMonkey • trace JIT • Type Inference • removed • Compiler optimization

IonMonkey• SSA• function inline• linear-scan register allocation• dead code elimination• loop-invariant code motion• ...

http://www.arewefastyet.com/

Chakra (IE9)

Chakra• Interpreter/JIT• Type System (hidden class)• PICs• Delay parse• Use utf-8 internal

Unlocking the JavaScript Opportunity with Internet Explorer 9

Carakan (Opera)

Carakan• Register VM• Method JIT, Regex JIT• Hidden type• Function inline

Rhino and JVM

Rhino is SLOW, why?

Because JVM is slow?

JVM did’t support dynamic language well

Solution: invokedynamic

Hard to optimize in JVMBefore Caller Some tricks Method InvokedynamicAfter Caller Method method handle

One ring to rule them all?

Rhino + invokedynamic• Pros • Cons • Easier to implement • Only in JVM7 • Lots of great Java Libraries • Not fully optimized yet • JVM optimization for free • Hard to beat V8

Compiler optimization is HARD

It there an easy way?

LLVM• Clang, VMKit, GHC, PyPy, Rubinius ...• DragonEgg: replace GCC back-end• IR• Optimization• Link, Code generate, JIT• Apple

LLVM simplify

define i32 @foo(i32 %bar) nounwind ssp { entry: %bar_addr = alloca i32, align 4 %retval = alloca i32 %0 = alloca i32 %one = alloca i32 %"alloca point" = bitcast i32 0 to i32 store i32 %bar, i32* %bar_addr store i32 1, i32* %one, align 4 %1 = load i32* %bar_addr, align 4 %2 = load i32* %one, align 4 %3 = add nsw i32 %1, %2 store i32 %3, i32* %0, align 4int foo(int bar) { %4 = load i32* %0, align 4 int one = 1; store i32 %4, i32* %retval, align 4 return bar + one; br label %return} return:int main() { %retval1 = load i32* %retval foo(3); ret i32 %retval1} } define i32 @main() nounwind ssp { entry: %retval = alloca i32 %"alloca point" = bitcast i32 0 to i32 %0 = call i32 @foo(i32 3) nounwind ssp br label %return return: %retval1 = load i32* %retval ret i32 %retval1 }

define i32 @foo(i32 %bar) nounwind ssp {entry: %bar_addr = alloca i32, align 4 %retval = alloca i32 %0 = alloca i32 %one = alloca i32 %"alloca point" = bitcast i32 0 to i32 store i32 %bar, i32* %bar_addr store i32 1, i32* %one, align 4 %1 = load i32* %bar_addr, align 4 %2 = load i32* %one, align 4 %3 = add nsw i32 %1, %2 define i32 @foo(i32 %bar) nounwind readnone ssp { store i32 %3, i32* %0, align 4 entry: %4 = load i32* %0, align 4 %0 = add nsw i32 %bar, 1 store i32 %4, i32* %retval, align 4 ret i32 %0 br label %return }return: define i32 @main() nounwind readnone ssp { %retval1 = load i32* %retval entry:} ret i32 %retval1 Optimization } ret i32 undefdefine i32 @main() nounwind ssp {entry: %retval = alloca i32 %"alloca point" = bitcast i32 0 to i32 %0 = call i32 @foo(i32 3) nounwind ssp br label %returnreturn: %retval1 = load i32* %retval ret i32 %retval1}

Optimization (70+) http://llvm.org/docs/Passes.html

define i32 @foo(i32 %bar) nounwind readnone ssp {entry: %0 = add nsw i32 %bar, 1 ret i32 %0} LLVM backenddefine i32 @main() nounwind readnone ssp {entry: ret i32 undef}

exe & Libraries LLVM LLVM exe & Offline Reoptimizer LLVM Compiler FE 1 LLVM Native exe Profile . CPU Info LLVM Linker CodeGen Profile & Trace . .o files IPO/IPA LLVM exe Info Runtime Compiler FE N JIT LLVM Optimizer LLVM LLVM Figure 4: LLVM system architecture diagramcode in non-conforming languages is executed as “un-managed code”. Such code is represented in native External static LLVM compilers (referred to as front-eform and not in the CLI intermediate representation, translate source-language programs into the LLVM virso it is not exposed to CLI optimizations. These sys- instruction set. Each static compiler can perform threetems do not provide #2 with #1 or #3 because run- tasks, of which the ﬁrst and third are optional: (1) Pertime optimization is generally only possible when us- language-speciﬁc optimizations, e.g., optimizing closureing JIT code generation. They do not aim to provide languages with higher-order functions. (2) Translate so

LLVM on JavaScript

Emscripten• C/C++ to LLVM IR• LLVM IR to JavaScript• Run on browser

... function _foo($bar) {define i32 @foo(i32 %bar) nounwind readnone ssp { var __label__;entry: var $0=((($bar)+1)|0); %0 = add nsw i32 %bar, 1 return $0; ret i32 %0 }} function _main() {define i32 @main() nounwind readnone ssp { var __label__;entry: return undef; ret i32 undef }} Module["_main"] = _main; ...

Emscripten demo• Python, Ruby, Lua virtual machine (http://repl.it/)• OpenJPEG• Poppler• FreeType• ... https://github.com/kripken/emscripten/wiki

Performance? good enough! benchmark SM V8 gcc ratio two Ja fannkuch (10) 1.158 0.931 0.231 4.04 benchm fasta (2100000) 1.115 1.128 0.452 2.47 operati primes 1.443 3.194 0.438 3.29 code th raytrace (7,256) 1.930 2.944 0.228 8.46 to usin dlmalloc (400,400) 5.050 1.880 0.315 5.97 (The m ‘nativiz The ﬁrst column is the name of the benchmark, and in Beinparentheses any parameters used in running it. The source C++ co

JavaScript on LLVM

Fabric Engine• JavaScript Integration• Native code compilation (LLVM)• Multi-threaded execution• OpenGL Rendering

Fabric Enginehttp://fabric-engine.com/2011/11/server-performance-benchmarks/

Conclusion?

All problems in computer science can be solvedby another level of indirection David Wheeler

References• The behavior of efﬁcient virtual • Context Threading: A Flexible machine interpreters on and Efﬁcient Dispatch modern architectures Technique for Virtual Machine Interpreters• Virtual Machine Showdown: Stack Versus Registers • Effective Inline-Threaded Interpretation of Java Bytecode• The implementation of Lua 5.0 Using Preparation Sequences• Why Is the New Google V8 • Smalltalk-80: the language and Engine so Fast? its implementation

References• Design of the Java HotSpotTM • LLVM: A Compilation Client Compiler for Java 6 Framework for Lifelong Program Analysis &• Oracle JRockit: The Deﬁnitive Transformation Guide • Emscripten: An LLVM-to-• Virtual Machines: Versatile JavaScript Compiler platforms for systems and processes • An Analysis of the Dynamic Behavior of JavaScript• Fast and Precise Hybrid Type Programs Inference for JavaScript

References• Adaptive Optimization for SELF • Design, Implementation, and Evaluation of Optimizations in a• Bytecodes meet Combinators: Just-In-Time Compiler invokedynamic on the JVM • Optimizing direct threaded• Context Threading: A Flexible code by selective inlining and Efﬁcient Dispatch Technique for Virtual Machine • Linear scan register allocation Interpreters • Optimizing Invokedynamic• Efﬁcient Implementation of the Smalltalk-80 System

References• Representing Type Information • The Structure and Performance in Dynamically Typed of Efﬁcient Interpreters Languages • Know Your Engines: How to• The Behavior of Efﬁcient Virtual Make Your JavaScript Fast Machine Interpreters on Modern Architectures • IE Blog, Chromium Blog, WebKit Blog, Opera Blog,• Trace-based Just-in-Time Type Mozilla Blog, Wingolog’s Blog, Specialization for Dynamic RednaxelaFX’s Blog, David Languages Mandelin’s Blog...

!ank y"

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Virtual machine and javascript engine

by Duoyi Wu on Dec 21, 2011

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