WebAssembly. neither Web nor Assembly, but Revolutionary

Transcription

1 WebAssembly neither Web nor Assembly, but Revolutionary

2 The WebAssembly revolution has begun

3 Jay Phelps Chief Software Architect previously

4 Support, Dev Rel, Staff Augmentation, Mentorship, and more

5 So...what is WebAssembly? aka Wasm

6 Efficient, safe, low-level bytecode for the Web

7 Efficient, safe, low-level bytecode for the Web

8 Fast to load and execute

9 Streaming compilation compiled to machine code faster than it downloads

10

11

12 .wasm (func $0 (type 0) i32.const 0 i32.load ) (func $1 (type 0) i32.const 0 i32.load ) (func $2 (type 0) i32.const 0 i32.load ) (func $3 (type 0) i32.const 0 i32.load )

13 .wasm machine code (func $0 (type 0) i32.const 0 i32.load ) (func $1 (type 0) i32.const 0 i32.load ) (func $2 (type 0) i32.const 0 i32.load ) (func $3 (type 0) i32.const 0 i32.load )

14 .wasm machine code (func $0 (type 0) i32.const 0 i32.load ) (func $1 (type 0) i32.const 0 i32.load ) (func $2 (type 0) i32.const 0 i32.load ) (func $3 (type 0) i32.const 0 i32.load )

15 .wasm machine code wasm-function[0]: sub rsp, 8 mov eax, dword ptr [r15] nop add rsp, 8 wasm-function[1]: sub rsp, 8 mov eax, dword ptr [r15] nop add rsp, 8 wasm-function[2]: sub rsp, 8 mov eax, dword ptr [r15] nop add rsp, 8 wasm-function[3]: sub rsp, 8 mov eax, dword ptr [r15] nop add rsp, 8

16 Efficient, safe, low-level bytecode for the Web

17 Sandboxed and designed with security in mind Control-flow integrity checks, stack protection, dynamic dispatch table separate from linear memory

18 However, does not prevent all classes of exploits Code reuse, side channel, race conditions, etc

19 Efficient, safe, low-level bytecode for the Web

20 WebAssembly is a portable, binary instruction set for a virtual machine

21 0x6a (the i32.add instruction)

22 Intended (mostly) as a compilation target

23 int factorial(int n) { if (n == 0) { return 1; } else { return n * factorial(n - 1); } }

24 int factorial(int n) { if (n == 0) { return 1; } else { return n * factorial(n - 1); } } D F 01 7F A 9D F 0B B C 0B

25 Efficient, safe, low-level bytecode for the Web

26 How did we get here?

27 Primary goals: languages other than JavaScript and great ideally improved performance

28 Java Applets Never truly integrated into browsers

29 Why not integrate the JVM or CLR? misaligned goals, mostly related to validation/compiling

30 Portable Native Client (PNaCl) lead by Google

31 asm.js lead by Mozilla

32 C asm.js "use asm" size_t strlen(char *ptr) { char *curr = ptr; while (*curr!= 0) { curr++; } return (curr - ptr); } function strlen(ptr) { ptr = ptr 0; var curr = 0; curr = ptr; while (MEM8[curr] 0!= 0) { curr = (curr + 1) 0; } return (curr - ptr) 0; }

33 ! WebAssembly!

34 WebAssembly is an unprecedented collaboration

35 The first open and standardized bytecode

36 Is it going to kill JavaScript?

37 Is it going to kill JavaScript?

38 Nope!

39 Will we compile JavaScript to WebAssembly?

40 JavaScript is an extremely dynamic language

41

42 Fully spec compliant JavaScript compiled to WebAssembly would be slower

43 but a strict subset of JavaScript could be fast!

44

45

46 WebAssembly v1 MVP is best suited for languages like C/C++ and Rust

47 Ideal for relatively low-level, system languages Very little dynamic features at run-time, no GC

48 Some modern features of C++ don t perform ideal

49 Exceptions are the most common example

50 But other languages are already supported, and more planned Things like Go,.NET, Java, OCaml, and even new ones

51 WebAssembly will impact language design and implementation

52 The Web requires unique considerations

53 Rust team has specifically called out WebAssembly as a priority

54 File sizes as well as lazy-loading/code splitting, caching, etc

55 Shared libraries Traditional platforms like ios/android/macos/ Windows have more robust stdlibs and UI toolkits

56 Offline Caching story much more complex than desktop

57 Interop with JavaScript Languages which better interop with JS have major advantage

58 Promising: Dart, Elm, Reason Languages designed for the Web

59 a TypeScript-like language? AssemblyScript is an early example

60 AssemblyScript export function factorial(n: i32): i32 { if (n == 0) { return 1; } else { return n * factorial(n - 1); } }

61 When should I target WebAssembly right now?

62 Heavily CPU-bound number computations

63 Games both Unity and Unreal Engine offer support

64 Using existing portable code e.g. video/audio decoders and other processing

65 hunspell RLWE McEliece mcl Zopfli ttf2woff2 bcrypt web-dsp OpenCV SIDH bls SPHINCS XSalsa20 xxhash GDAL NTRU

66 Zoom for Web client Video conferencing powered by WebAssembly, video/audio decoding off the main thread

67 react-native-dom (not react-native-web)

68 Web UI developers are probably already using WebAssembly without knowing it!

69 source-map npm package used by Firefox, Babel, create-react-app, LESS, etc 10.9x faster!

70 Other use cases are just around the corner

71 What was that binary stuff?

72 int factorial(int n) { if (n == 0) { return 1; } else { return n * factorial(n - 1); } } D F 01 7F A 9D F 0B B C 0B

73 D F 01 7F A 9D F 0B B C 0B

74 D F 01 7F A 9D F 0B B C 0B

75 D F 01 7F A 9D F 0B B C 0B

76

77

78

79 Binary can be a little intimidating

80 Protip: don't worry about it (unless of course, you want to)

81 Tooling will eventually make it a non-issue

82 Textual representation to the rescue!

83 (func $factorial (param $n i32) (result i32) get_local $n i32.const 0 i32.eq if $if0 i32.const 1 return end $if0 get_local $n i32.const 1 i32.sub call $factorial get_local $n i32.mul )

84 (func $factorial (param $n i32) (result i32) get_local $n i32.const 0 i32.eq if $if0 i32.const 1 return end $if0 get_local $n i32.const 1 i32.sub call $factorial get_local $n i32.mul )

85 Let's learn the fundamentals

86 WebAssembly is a stack machine

87 ...what's a stack machine?

88 Stack a data structure with two operations: push and pop

89 stack machine: instructions on a stack

90 Why a stack machine? instead of AST, SSA, or register machine

91 Smaller binary encoding, easier and faster single pass verification and VM implementation

92 1 + 2

93 opcode mnemonics i32.add 0x6a

94 i32.const 1 i32.const 2 i32.add

95 i32.const 1 i32.const 2 i32.add stack

96 i32.const 1 i32.const 2 i32.add stack

97 i32.const 1 i32.const 2 i32.add 1 stack

98 i32.const 1 i32.const 2 i32.add 1 stack

99 i32.const 1 i32.const 2 i32.add 2 1 stack

100 i32.const 1 i32.const 2 i32.add 2 1 stack

101 2 1 i32.const 1 i32.const 2 i32.add stack

102 3 i32.const 1 i32.const 2 i32.add stack

103 i32.const 1 i32.const 2 i32.add 3 stack

104 i32.const 1 i32.const 2 i32.add

105 i32.const 1 i32.const 2 i32.add call $log

106 What's missing?

107 Direct access to Host APIs (e.g. the DOM) no direct access to sys calls, you have to call into JavaScript

108 Garbage collection necessary for better interop with JavaScript and WebIDL (e.g. the DOM)

109 Multi-threading SharedArrayBuffer re-enabled in Chrome 68

110 Single Instruction Multiple Data (SIMD) Hardware parallelization of vector computations

111 Zero-cost exceptions someday maybe even Algebraic Effects (!!!)

112 There's more, but advancing quickly!

113 How do I get started?

114 webassembly.org

115

116 Supported in all modern browsers

117 The revolution is just beginning

118 Efficient, safe, low-level bytecode for the Web

119 Efficient, safe, low-level bytecode for the Web?

120 The first open and standardized bytecode

121

122

123 WebAssembly is not just for the Web!

124

125 ewasm Etherium-flavored WebAssembly VM for running distributed smart contracts

126 rianhunter/wasmjit VM and Linux kernel module for running WebAssembly in ring 0

127 nebulet microkernel that runs WebAssembly exclusively

128 Efficient, safe, low-level bytecode for the Web

129 Efficient, safe, low-level bytecode for the Web

130 Thanks!