jeetah

jeetah is an experimental compiler for mathematical expressions in JavaScript with MP support

Depending on the outcome, it (might) replace (one day) partially (or fully) the current ExprTk backend in ExprTk.js

Project Goals

jeetah aims to solve the following goals:
* True compiler, producing machine code from mathematical expressions
* Always faster than V8, for any expression, even in mono-threaded sync mode
* True JavaScript syntax replacing the ExprTk syntax, working from V8 representation
* Support a subset of the JavaScript language with a single variable type per function as the current ExprTk syntax
* Support only TypedArrays
* Support array traversal with fusing of the expression logic into the array logic and zero subroutine calls
(stretch goal)* Add SSE to MIR (probably as manual custom instructions) and support SSE operations

Implementation

* Front-end parsing by acorn
jeetah compiling to MIR - Medium Intermediate Representation*
* Back-end register allocation and machine code assembly by MIR

Status

Not usable
Very early stage
Very small subset of the JS language functional

Example

Input
``js
compile(function lapseRate(temp, height) {
const g = 9.81;
const c = 1005;
const Gamma = g / c;
return temp - height * Gamma;
});
`

Output
`
m_lapseRate: module
export lapseRate
lapseRate: func d, d:temp, d:height
local d:g, d:c, d:Gamma, d:_expr_0, d:_expr_1, d:_expr_2
dmov g, 9.8100000000000005
dmov c, 1005.0000000000000000
dmov _expr_0, g
ddiv _expr_0, g, c
dmov Gamma, _expr_0
dmov _expr_1, temp
dmov _expr_2, height
dmul _expr_2, height, Gamma
dsub _expr_1, temp, _expr_2
ret _expr_1
endfunc
endmodule
`

Performance

Preliminary results show performance very close to clang -O3` with an inline loop.