Asm.js introduction
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Asm.js is a strict subset of JavaScript designed for performance, using low-level features like typed arrays and allowing backward compatibility without plugins. It enables the use of LLVM tools like Emscripten to compile applications written in C/C++ into asm.js. Major browsers like Firefox and Microsoft's Edge have implemented specific optimizations for asm.js, significantly improving performance for web applications.
Asm.js introduction
- 1. Asm.js introduction _by Oleksii Prohonnyi
- 2. OUT OF SCOPE
- 3. No information in this presentation WebAssembly NaCl / PNaCl LLVM JavaScript Engines Performance AOT compilation process OdinMonkey by Mozilla Chakra by Microsoft V8 by Google
- 4. HISTORY
- 5. History JavaScript is one of the world’s most popular programming languages. Back in the day, transpilers (source-to-source compilers) were used to hide some of JavaScript’s ugly parts, e.g. CoffeeScript, ClojureScript, TypeScript. Transpilers mainly use an existing language (such as C or C++) or, they define a new language (like CoffeeScript). Then, instead of writing JavaScript, you can develop in this other language that the transpiler converts to JavaScript.
- 6. Compiling to JavaScript: Nothing New! Google Web Toolkit (GWT), Java to JS pyjamas, Python into JS Opal, Ruby to JavaScript JSIL, .NET to JavaScript Scala.js, Scala to JavaScript etc.
- 7. OVERVIEW
- 8. What is asm.js? asm.js is a strict subset of JavaScript. asm.js takes advantage of some low level JavaScript features like Typed Arrays. It does not use any plugins or modules to run the JavaScript code, making it backward compatible. http://asmjs.org/
- 9. HOW IT WORKS
- 10. JavaScript vs asm.js JavaScript asm.js
- 11. GENERATORS
- 12. Emscripten Emscripten is an LLVM-to-JavaScript compiler. Emscripten accepts LLVM bytecode and converts them to asm.js JavaScript. Clang could be used to convert C/C++ codes to LLVM. http://kripken.github.io/emscripten-site/
- 14. Code generation process 1. Create a C/C++ app. 2. Compile it using Clang to generate LLVM bytecode. 3. Pass the bytecode to Emscripten to get the JavaScript code. Emscripten performs the last two steps itself.
- 15. BROWSER SUPPORT
- 16. Browser support Mozilla Firefox implements asm.js-specific optimizations, starting with Firefox 22. OdinMonkey, Mozilla's asm.js ahead-of-time compiler used in Firefox. Microsoft is implementing support for asm.js in Chakra, the JavaScript engine used by Microsoft Edge, performing validation to produce highly optimized JIT code. The optimizations of Google Chrome's V8 JavaScript engine in Chrome 28 made asm.js benchmarks more than twice as fast as prior versions of Chrome, although Chrome's V8 does not use ahead-of-time compilation.
- 17. Browser support
- 18. EXAMPLE
- 20. C++ snippet
- 21. Code generation Install Emscripten (https://github.com/kripken/emscripten/wiki). Convert C++ code to asm.js code: “./emcc -O1 -s ASM_JS=1 ./hello_world.cpp” Code execution with node.js: “node ./a.out.js” Download Clang (http://clang.llvm.org/) Convert C++ code to bytecode: “clang ./hello_world.cpp”
- 24. REFERENCES
- 25. See more http://asmjs.org/ https://github.com/kripken/emscripten Big Web App? Compile It! (Alon Zakai / Mozilla) Asm.js JavaScript compile target (John Resig / Blog) Understanding asm.js (Sitepoint) From asm.js to WebAssembly (Brendan Eich / Blog) Mozilla Hacks