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code-423n4 / 2022-07-axelar-findings

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Gas Optimizations #171

Open code423n4 opened 2 years ago

code423n4 commented 2 years ago

get the keccak hash ofline and put that value to constant to save gas

https://github.com/code-423n4/2022-07-axelar/blob/3373c48a71c07cfce856b53afc02ef4fc2357f8c/contracts/AxelarGateway.sol#L30-L44

when getting the keccak hash of value you should make the variables immutable to save gas

https://github.com/code-423n4/2022-07-axelar/blob/3373c48a71c07cfce856b53afc02ef4fc2357f8c/contracts/AxelarGateway.sol#L30-L44

onlyowner functions can be made payable because payable there is no check if msg.value ==0

https://github.com/code-423n4/2022-07-axelar/blob/a1205d2ba78e0db583d136f8563e8097860a110f/xc20/contracts/XC20Wrapper.sol#L44-L46 https://github.com/code-423n4/2022-07-axelar/blob/a1205d2ba78e0db583d136f8563e8097860a110f/xc20/contracts/XC20Wrapper.sol#L44-L73

make i++ into ++i to save 3 gas on a copy

AxelarGateway.sol:207:        for (uint256 i = 0; i < symbols.length; i++) {
deposit-service/AxelarDepositService.sol:114:        for (uint256 i; i < refundTokens.length; i++) {
deposit-service/AxelarDepositService.sol:168:        for (uint256 i; i < refundTokens.length; i++) {
deposit-service/AxelarDepositService.sol:204:        for (uint256 i; i < refundTokens.length; i++) {
gas-service/AxelarGasService.sol:123:        for (uint256 i; i < tokens.length; i++) {

cache array.lenght to a memory variable

    AxelarGateway.sol:207:        for (uint256 i = 0; i < symbols.length; i++) {
deposit-service/AxelarDepositService.sol:114:        for (uint256 i; i < refundTokens.length; i++) {
deposit-service/AxelarDepositService.sol:168:        for (uint256 i; i < refundTokens.length; i++) {
deposit-service/AxelarDepositService.sol:204:        for (uint256 i; i < refundTokens.length; i++) {
gas-service/AxelarGasService.sol:123:        for (uint256 i; i < tokens.length; i++) {

make i unchecked when it wont overflow

you are saving gas on solidity not checking on an overflow 

    AxelarGateway.sol:207:        for (uint256 i = 0; i < symbols.length; i++) {
deposit-service/AxelarDepositService.sol:114:        for (uint256 i; i < refundTokens.length; i++) {
deposit-service/AxelarDepositService.sol:168:        for (uint256 i; i < refundTokens.length; i++) {
deposit-service/AxelarDepositService.sol:204:        for (uint256 i; i < refundTokens.length; i++) {
gas-service/AxelarGasService.sol:123:        for (uint256 i; i < tokens.length; i++) {
re1ro commented 2 years ago

1

Compiler does that

2

Dup #12

3

Dup #7 (5)

4 - 6

Dup #2

GalloDaSballo commented 2 years ago

when getting the keccak hash of value you should make the variables immutable to save gas

Not true for ages (maybe like 4 years) https://twitter.com/GalloDaSballo/status/1543729080926871557

Rest will save less than 300 gas