The document discusses emscripten, a compiler that converts C/C++ to JavaScript, and aobench, an ambient occlusion benchmark. It presents results showing a raytracing demo taking 12.8 seconds to run in Chrome and 82.92 seconds in Firefox. It also briefly mentions using the Closure Compiler to optimize the generated JavaScript and compiling to LLVM IR before emitting JavaScript.

1. emscripten
aobench
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2. Agenda
• emscripten
• aobench
•
• Performance
•
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3. emscripten
• C/C++ -> JavaScript compiler
• LLVM IR JS
• clang, llvm-gcc C/C++ LLVM
IR .
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4. aobench
• AmbientOcclusion ,
CG
•
.
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5. • raytrace
.
• clang LLVM IR
• emscripten LLVM IR -> JS
• web
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6. •
• compile , js .
• ...
• Firebug .
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7. include file
• #include “emscripten.h”
• C/C++
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8. • rand() .
•
• -> (
?)
xorshift
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9. double *pixels = new double[3 * x];
@llvm.umul.with.overflow.i64
->
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10. optimize
• opt -std-compile-opts LLVM IR
.
• ...
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11. js code
• JS
var args = arguments;
// arguments .
// var args = []
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12. Performance
Chrome Firefox
90
• Chrome 12.8 secs 67.5
• Firefox 82.92 secs 45
• Safari ... 22.5
0
secs
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13. Closure compiler
• Closure compiler(JS -> JS optimizer)
JS
.
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14. • JS JS
.
• C JS
.
• LLVM IR
• lowlevel
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