Description:
Solidity 0.6.5 introduced immutable as a major feature. It allows setting contract-level variables at construction time which gets stored in code rather than storage. Each call to it reads from storage, using a sload costing 2100 gas cold or 100 gas warm. Setting it to immutable will have each storage read of the state variable to be replaced by the instruction push32 value, where value is set during contract construction time and this costs only 3 gas.
Recommendation:
Set the state variable to immutable.
Description:
The dynamic array arr has the storage location memory. When the function gets called externally, the array values are kept in calldata and copied to memory during ABI decoding (using the opcode calldataload and mstore). And during the for loop, arr[i] accesses the value in memory using a mload.
Recommendation:
Use calldata instead of memory for function parameters to avoid using memory with array values when a function is getting called externally.
[NAZ-G6] For array elements, arr[i] = arr[i] + 1 is cheaper than arr[i] += 1
Description:
Infinity can also be represented via `2**255, it's hex representation is 0x8000000000000000000000000000000000000000000000000000000000000000 while 2**256 - 1 is 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff. Then main difference is and where the gas savings come from is, zeros are cheaper than non-zero values in hex representation.
Recommendation:
Use 2**255 instead of 2**256 - 1 to save gas on deployment.
Description:
You can cut out 10 opcodes in the creation-time EVM bytecode if you declare a constructor payable. Making the constructor payable eliminates the need for an initial check of msg.value == 0 and saves 21 gas on deployment with no security risks.
Description:
Contracts most called functions could simply save gas by function ordering via Method ID. Calling a function at runtime will be cheaper if the function is positioned earlier in the order (has a relatively lower Method ID) because 22 gas are added to the cost of a function for every position that came before it. The caller can save on gas if you prioritize most called functions. One could use This tool to help find alternative function names with lower Method IDs while keeping the original name intact.
Recommendation:
Find a lower method ID name for the most called functions for example mostCalled() vs. mostCalled_41q() is cheaper by 44 gas.
[NAZ-G1] Moving
if (proposalHasBeenActivated[proposalId_] == true)Context:
Governance.sol#L230-L232Description: Moving:
earlier in
activateProposal()will make it fail sooner and save gas.Recommendation: Consider moving
if (proposalHasBeenActivated[proposalId_] == true)earlier inactivateProposal()[NAZ-G2] State Variables That Can Be Set To
ImmutableContext:
BondCallback.sol#L28,BondCallback.sol#L32Description: Solidity
0.6.5introducedimmutableas a major feature. It allows setting contract-level variables at construction time which gets stored in code rather than storage. Each call to it reads from storage, using asloadcosting 2100 gas cold or 100 gas warm. Setting it toimmutablewill have each storage read of the state variable to be replaced by the instructionpush32 value, wherevalueis set during contract construction time and this costs only 3 gas.Recommendation: Set the state variable to
immutable.[NAZ-G3] Right Shift Instead of Dividing By 2
Context:
Operator.sol#L372,Operator.sol#L427Description: The
SHRopcode is 3 gas cheaper thanDIVand also bypasses Solidity's division by 0 prevention overhead.Recommendation: Consider using right shift instead of dividing by 2.
[NAZ-G4] Functions Visibility Can Be Declared External
Context:
Kernel.sol#L439,Kernel.sol#L451,TRSRY.sol#L75,MINTR.sol#L33,MINTR.sol#L37,RANGE.sol#L215,VOTES.sol#L45,VOTES.sol#L51,INSTR.sol#L37,Governance.sol#L145,Governance.sol#L151Description: Several functions across multiple contracts have a public visibility and can be marked with external visibility to save gas.
Recommendation: Change the functions visibility to external to save gas.
[NAZ-G5] Use
calldataInstead ofmemoryFor Function ParametersContext:
TreasuryCustodian.sol#L53,BondCallback.sol#L152Description: The dynamic array arr has the storage location memory. When the function gets called externally, the array values are kept in calldata and copied to memory during ABI decoding (using the opcode calldataload and mstore). And during the for loop, arr[i] accesses the value in memory using a mload.
Recommendation: Use
calldatainstead ofmemoryfor function parameters to avoid using memory with array values when a function is getting called externally.[NAZ-G6] For array elements,
arr[i] = arr[i] + 1is cheaper thanarr[i] += 1Context:
TRSRY.sol#L96-L97,TRSRY.sol#L131,VOTES.sol#L58,BondCallback.sol#L143-L144,Governance.sol#L198,Governance.sol#L252,Governance.sol#254Description: Due to stack operations this is 25 gas cheaper when dealing with arrays in storage, and 4 gas cheaper for memory arrays.
Recommendation: Use
arr[i] = arr[i] + 1instead ofarr[i] += 1when dealing with arrays[NAZ-G7] Use
++indexinstead ofindex++to increment a loop counterContext:
KernelUtils.sol#L49,KernelUtils.sol#L64Description: Due to reduced stack operations, using
++indexsaves 5 gas per iteration.Recommendation: Use
++indexto increment a loop counter.[NAZ-G8] Use of
2**256 - 1 && type(uint256).maxWhen2**255Can Be UsedContext:
TRSRY.sol#L147,RANGE.sol#L88,RANGE.sol#L95,RANGE.sol#L221,RANGE.sol#L230,Operator.sol#L167,Operator.sol#L477,Operator.sol#L603,BondCallback.sol#L57,BondCallback.sol#L95Description: Infinity can also be represented via
`2**255, it's hex representation is0x8000000000000000000000000000000000000000000000000000000000000000while2**256 - 1is0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff. Then main difference is and where the gas savings come from is, zeros are cheaper than non-zero values in hex representation.Recommendation: Use
2**255instead of2**256 - 1to save gas on deployment.[NAZ-G9] Setting The Constructor To Payable
Context:
All ContractsDescription: You can cut out 10 opcodes in the creation-time EVM bytecode if you declare a constructor payable. Making the constructor payable eliminates the need for an initial check of
msg.value == 0and saves 21 gas on deployment with no security risks.Recommendation: Set the constructor to payable.
[NAZ-G10] Function Ordering via Method ID
Context:
All ContractsDescription: Contracts most called functions could simply save gas by function ordering via Method ID. Calling a function at runtime will be cheaper if the function is positioned earlier in the order (has a relatively lower Method ID) because 22 gas are added to the cost of a function for every position that came before it. The caller can save on gas if you prioritize most called functions. One could use
This toolto help find alternative function names with lower Method IDs while keeping the original name intact.Recommendation: Find a lower method ID name for the most called functions for example
mostCalled()vs.mostCalled_41q()is cheaper by 44 gas.