linprima

node+browser asmjs implementation of esprima

Esprima is one of the most highly used libraries in Node js, it sees something like 70k downloads a day. Significant computational-hours could be saved by developing a much faster drop-in replacement of Esprima.

The project also aims to demonstrate the viability of transpiling to ASMJS for unrivaled performance gains in small, everyday libraries and applications.

Related work

the only competitors to esprima on speed simply cannot match its functionality 1-to-1. And are limited in their advantage for large files because of the low ceiling and diminishing returns on pure, non-asmjs optimization.

Status

Currently the stable branch passes all but 4 of esprima's ~750 unit tests. Stable branch is at ~120% performance within FF with minimal options (see bench/ folder).

Concurrent branch changes (switch to pared-down Write-Only Json class) likely to bring performance up quite a bit.

Motive

This project aims to demonstrate the viability of emscripten-compiled asmjs for small, basic libraries. Currently, asmjs is seen as some niche tool for niche uses like media editing or 3d graphics.

This project aims to be a case study in ASMJS' viability, but also the cutting-edge speed advantage in can provide in applications with continuous-processing.

As well, this project contains several innovations regarding retaining compatibility with the javascript ecosystem of functioning across browsers and with a variety of module loaders (requirejs, node, and bower in addition to independent use as a script)

Build instructions

You'll need to get a recent version of emscripten, please see emscripten's downloads and instructions page.

after that's installed and emcc is on your path:

sudo apt-get install scons npm 

npm install

#ASMJS (builds to build/asm/)
gulp asmjs

#library (builds to build/linprima.so)
#and node-FFI (builds to build/ffi/)
gulp clang

Profiling and analysis

# memory profiling (massif)
# (outputs to folder in tmp/mem/)
gulp mem

# llvm (no emcc) flat profiling
# uses Profiny.h
# (outputs to tmp/profiny.flat.csv)
# best viewed in a spreadsheet app
# like gnumeric, etc.
gulp prof

# llvm (no emcc) callgraph profiling
# (outputs to tmp/profiny.graphed.out)
# results best viewed with a log viewer
gulp prof --graph

# memcheck
# check for and resolve any memory 
# leaks on edit (for the test case in
# tests/codetotest.js)
gulp clang --gdb
valgrind --leak-check=full tmp/test_gdb