• Select0r
  • 🔭 Overview
  • 📦 Install Rust
  • 🔧 Build
  • 🚀 How to run
    • 💻 Usage
    • ✏️ Parameters
    • 👉 Examples
  • 📝 Results
  • 🎉 Yad bonus !
    • 📦 Installation
    • 💻 Script
  • TO DO

Solidity functions can achieve higher efficiency when their function selector consists mainly of zeros.

This tool helps you to generate a new selector for your Solidity contracts and save gas costs by using the smallest possible selector.

For instance :

• sendValue(uint256 amount) is invalid.
• sendValue(uint256) is the correct format.

The gas cost of a function name equals 4 times the number of zero bytes and 16 times the number of non-zero bytes. Therefore, the gas cost ranges from 28 gas (3 zeros and 1 non-zero) in the best case to 64 gas (4 non-zero bytes) in the worst case.

1. It's important to note that an all-zero function selector won't compile because it conflicts with the fallback function. Consequently, mint_22F5A30(uint256) (0a000000) is more gas-efficient than mint(uint256) (a0712d68).

2. Function selectors with leading zeros affect the operation of the function dispatcher and can be processed more quickly with less gas consumption.

This Rust program (select0r) is designed to find better names for an EVM (Ethereum Virtual Machine) function to optimize gas cost. It takes a function signature as input and performs calculations to find the best EVM function names in terms of gas cost.

For more informations about gas optimisation related to function names, go check my article, please follow and share it !

Links :

• GitHub - Laugharne/Optimal_Function_Names
• Optimisation des EVM, avec les noms de fonctions | Medium 🇫🇷
• Optimization on Ethereum: Make a Difference with Function Names 🇬🇧

Feel free to contact me !

https://www.rust-lang.org/tools/install

Build artifacts in release mode, with optimizations.

cargo build --release

Go into release sub-directory as working directory and launch select0r.

select0r s <function_signature string> z <number_of_zeros> r <max_results> l <leading_zero boolean> t <nbr_threads> o <format_ouput>

• (1) : no spaces, no parameter names, just a valid solidity signature
• (2) : higher it is, longer it is
• (3) : search for leading zeros in priority, slower if true
• (4) : hardware limitation (#CPU)
• (5) : File formats
  • tsv = Tab Separated Value
  • csv = Comma Separated Value
  • json = JavaScript Object Notation
  • xml = Extensible Markup Language
  • ron = Rusty Object Notation

select0r s "functionName(uint256)"  z 2  r 5  l true  t 2  o tsv

select0r s "functionName2(uint)"  z 2  r 7  l false  t 2  o json

select0r s "deposit(uint)"  z 2  r 7  l false  t 2  o xml

Get results for execute() signature looking for 2 lead zeros minimum, using 15 threads, stop after8 results and put it as an XML file.

select0r s "execute()"  z 2  l true  t 15  r 8  o xml

An ouput file appears with the initial signature and some parameters in its name.

File : select0r-execute()--zero=2-max=8-lead=true-cpu=15.XML

<?xml version="1.0" encoding="UTF-8"?>
<select0r>
    <result>
        <selector>61461954</selector>
        <nbr_of_zero>0</nbr_of_zero>
        <leading_zero>0</leading_zero>
        <signature>execute()</signature>
    </result>
    <result>
        <selector>1b9b0000</selector>
        <nbr_of_zero>2</nbr_of_zero>
        <leading_zero>0</leading_zero>
        <signature>execute_1qn()</signature>
    </result>
    <result>
        <selector>00af0043</selector>
        <nbr_of_zero>2</nbr_of_zero>
        <leading_zero>1</leading_zero>
        <signature>execute_5Hw()</signature>
    </result>
    <result>
        <selector>00940050</selector>
        <nbr_of_zero>2</nbr_of_zero>
        <leading_zero>1</leading_zero>
        <signature>execute_6Ii()</signature>
    </result>
    <result>
        <selector>0000eb63</selector>
        <nbr_of_zero>2</nbr_of_zero>
        <leading_zero>2</leading_zero>
        <signature>execute_mAX()</signature>
    </result>
    <result>
        <selector>0000cf6d</selector>
        <nbr_of_zero>2</nbr_of_zero>
        <leading_zero>2</leading_zero>
        <signature>execute_G5J()</signature>
    </result>
    <result>
        <selector>00000622</selector>
        <nbr_of_zero>2</nbr_of_zero>
        <leading_zero>2</leading_zero>
        <signature>execute_06SF()</signature>
    </result>
    <result>
        <selector>000000ae</selector>
        <nbr_of_zero>3</nbr_of_zero>
        <leading_zero>3</leading_zero>
        <signature>execute_6d4S()</signature>
    </result>
</select0r>

Yad (« Yet Another Dialog ») is a tool to create graphic dialog boxes with shell scripts.

sudo apt install yad

There is the code to provide graphical interface to select0r tool.

Just set path to select0r binary executable and wrap it into a shell script or a bash function.

select0r=$(yad \
--title='Select0r' \
--form --width 400 --height 300 \
--field="<b>Find better function name to optimize gas cost.</b>":LBL '' \
--field="":LBL '' \
--field="Signature" 'mint(address)' \
--field="Nbr of Results":CB '1\!2\!3\!^4\!5\!6\!7\!8\!9\!10\!11\!12' \
--field="Nbr of zero":CB '1\!^2\!3' \
--field="Nbr of Threads":CB '1\!^2\!3\!4\!5\!6\!7\!8\!9\!10\!11\!12\!13\!14\!15\!16' \
--field="Ouput":CB '^TSV\!CSV\!JSON\!XML' \
--field="Leading 0":CHK 'FALSE' \
)
signature=$(echo "$select0r" | awk 'BEGIN {FS="|" } { print $3 }')
nn_result=$(echo "$select0r" | awk 'BEGIN {FS="|" } { print $4 }')
nn_zero=$(echo "$select0r" | awk 'BEGIN {FS="|" } { print $5 }')
nn_threads=$(echo "$select0r" | awk 'BEGIN {FS="|" } { print $6 }')
output=$(echo "$select0r" | awk 'BEGIN {FS="|" } { print $7 }')
decrease=$(echo "$select0r" | awk 'BEGIN {FS="|" } { print $8 }')
path_to_select0r/select0r  s $signature  z $nn_zero  l $decrease  t $nn_threads  r $nn_result  o $output

• Add : Rows of String Values (RSV) format ouput GitHub - Stenway/RSV-Specification: Rows of String Values (RSV Data Format) Specification - A Binary Alternative to CSV
• Add : Simple Markup Language (SML) format output SML - The Simple Markup Language