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⚡️ Optimize ERC20 slot computation with bitwise operations #1507

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⚡️ Optimize ERC20 slot computation with bitwise operations #1507

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71 changes: 34 additions & 37 deletions src/tokens/ERC20.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -155,9 +155,7 @@ abstract contract ERC20 {
function balanceOf(address owner) public view virtual returns (uint256 result) {
/// @solidity memory-safe-assembly
assembly {
mstore(0x0c, _BALANCE_SLOT_SEED)
mstore(0x00, owner)
result := sload(keccak256(0x0c, 0x20))
result := sload(or(shl(224, _BALANCE_SLOT_SEED), shr(96, shl(96, owner))))
}
}

Expand Down Expand Up @@ -219,9 +217,8 @@ abstract contract ERC20 {
/// @solidity memory-safe-assembly
assembly {
// Compute the balance slot and load its value.
mstore(0x0c, _BALANCE_SLOT_SEED)
mstore(0x00, caller())
let fromBalanceSlot := keccak256(0x0c, 0x20)
let slot_seed := shl(224, _BALANCE_SLOT_SEED)
let fromBalanceSlot := or(slot_seed, caller())
let fromBalance := sload(fromBalanceSlot)
// Revert if insufficient balance.
if gt(amount, fromBalance) {
Expand All @@ -231,15 +228,15 @@ abstract contract ERC20 {
// Subtract and store the updated balance.
sstore(fromBalanceSlot, sub(fromBalance, amount))
// Compute the balance slot of `to`.
mstore(0x00, to)
let toBalanceSlot := keccak256(0x0c, 0x20)
let to_ := shr(96, shl(96, to))
let toBalanceSlot := or(slot_seed, to_)
// Add and store the updated balance of `to`.
// Will not overflow because the sum of all user balances
// cannot exceed the maximum uint256 value.
sstore(toBalanceSlot, add(sload(toBalanceSlot), amount))
// Emit the {Transfer} event.
mstore(0x20, amount)
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, caller(), shr(96, mload(0x0c)))
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, caller(), to_)
}
_afterTokenTransfer(msg.sender, to, amount);
return true;
Expand All @@ -260,11 +257,13 @@ abstract contract ERC20 {
if (_givePermit2InfiniteAllowance()) {
/// @solidity memory-safe-assembly
assembly {
let from_ := shl(96, from)
let from_ := shr(96, shl(96, from))
let to_ := shr(96, shl(96, to))
if iszero(eq(caller(), _PERMIT2)) {
// Compute the allowance slot and load its value.
mstore(0x20, caller())
mstore(0x0c, or(from_, _ALLOWANCE_SLOT_SEED))
mstore(0x0c, _ALLOWANCE_SLOT_SEED)
mstore(0x00, from_)
let allowanceSlot := keccak256(0x0c, 0x34)
let allowance_ := sload(allowanceSlot)
// If the allowance is not the maximum uint256 value.
Expand All @@ -279,8 +278,8 @@ abstract contract ERC20 {
}
}
// Compute the balance slot and load its value.
mstore(0x0c, or(from_, _BALANCE_SLOT_SEED))
let fromBalanceSlot := keccak256(0x0c, 0x20)
let slot_seed := shl(224, _BALANCE_SLOT_SEED)
let fromBalanceSlot := or(slot_seed, from_)
let fromBalance := sload(fromBalanceSlot)
// Revert if insufficient balance.
if gt(amount, fromBalance) {
Expand All @@ -290,23 +289,23 @@ abstract contract ERC20 {
// Subtract and store the updated balance.
sstore(fromBalanceSlot, sub(fromBalance, amount))
// Compute the balance slot of `to`.
mstore(0x00, to)
let toBalanceSlot := keccak256(0x0c, 0x20)
let toBalanceSlot := or(slot_seed, to_)
// Add and store the updated balance of `to`.
// Will not overflow because the sum of all user balances
// cannot exceed the maximum uint256 value.
sstore(toBalanceSlot, add(sload(toBalanceSlot), amount))
// Emit the {Transfer} event.
mstore(0x20, amount)
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, shr(96, from_), shr(96, mload(0x0c)))
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, from_, to_)
}
} else {
/// @solidity memory-safe-assembly
assembly {
let from_ := shl(96, from)
// Compute the allowance slot and load its value.
let from_ := shr(96, shl(96, from))
mstore(0x20, caller())
mstore(0x0c, or(from_, _ALLOWANCE_SLOT_SEED))
mstore(0x0c, _ALLOWANCE_SLOT_SEED)
mstore(0x00, from_)
let allowanceSlot := keccak256(0x0c, 0x34)
let allowance_ := sload(allowanceSlot)
// If the allowance is not the maximum uint256 value.
Expand All @@ -320,8 +319,8 @@ abstract contract ERC20 {
sstore(allowanceSlot, sub(allowance_, amount))
}
// Compute the balance slot and load its value.
mstore(0x0c, or(from_, _BALANCE_SLOT_SEED))
let fromBalanceSlot := keccak256(0x0c, 0x20)
let slot_seed := shl(224, _BALANCE_SLOT_SEED)
let fromBalanceSlot := or(slot_seed, from_)
let fromBalance := sload(fromBalanceSlot)
// Revert if insufficient balance.
if gt(amount, fromBalance) {
Expand All @@ -331,15 +330,15 @@ abstract contract ERC20 {
// Subtract and store the updated balance.
sstore(fromBalanceSlot, sub(fromBalance, amount))
// Compute the balance slot of `to`.
mstore(0x00, to)
let toBalanceSlot := keccak256(0x0c, 0x20)
let to_ := shr(96, shl(96, to))
let toBalanceSlot := or(slot_seed, to_)
// Add and store the updated balance of `to`.
// Will not overflow because the sum of all user balances
// cannot exceed the maximum uint256 value.
sstore(toBalanceSlot, add(sload(toBalanceSlot), amount))
// Emit the {Transfer} event.
mstore(0x20, amount)
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, shr(96, from_), shr(96, mload(0x0c)))
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, from_, to_)
}
}
_afterTokenTransfer(from, to, amount);
Expand Down Expand Up @@ -506,15 +505,14 @@ abstract contract ERC20 {
}
// Store the updated total supply.
sstore(_TOTAL_SUPPLY_SLOT, totalSupplyAfter)
let to_ := shr(96, shl(96, to))
// Compute the balance slot and load its value.
mstore(0x0c, _BALANCE_SLOT_SEED)
mstore(0x00, to)
let toBalanceSlot := keccak256(0x0c, 0x20)
let toBalanceSlot := or(shl(224, _BALANCE_SLOT_SEED), to_)
// Add and store the updated balance.
sstore(toBalanceSlot, add(sload(toBalanceSlot), amount))
// Emit the {Transfer} event.
mstore(0x20, amount)
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, 0, shr(96, mload(0x0c)))
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, 0, to_)
}
_afterTokenTransfer(address(0), to, amount);
}
Expand All @@ -530,10 +528,9 @@ abstract contract ERC20 {
_beforeTokenTransfer(from, address(0), amount);
/// @solidity memory-safe-assembly
assembly {
let from_ := shr(96, shl(96, from))
// Compute the balance slot and load its value.
mstore(0x0c, _BALANCE_SLOT_SEED)
mstore(0x00, from)
let fromBalanceSlot := keccak256(0x0c, 0x20)
let fromBalanceSlot := or(shl(224, _BALANCE_SLOT_SEED), from_)
let fromBalance := sload(fromBalanceSlot)
// Revert if insufficient balance.
if gt(amount, fromBalance) {
Expand All @@ -546,7 +543,7 @@ abstract contract ERC20 {
sstore(_TOTAL_SUPPLY_SLOT, sub(sload(_TOTAL_SUPPLY_SLOT), amount))
// Emit the {Transfer} event.
mstore(0x00, amount)
log3(0x00, 0x20, _TRANSFER_EVENT_SIGNATURE, shr(96, shl(96, from)), 0)
log3(0x00, 0x20, _TRANSFER_EVENT_SIGNATURE, from_, 0)
}
_afterTokenTransfer(from, address(0), amount);
}
Expand All @@ -560,10 +557,11 @@ abstract contract ERC20 {
_beforeTokenTransfer(from, to, amount);
/// @solidity memory-safe-assembly
assembly {
let from_ := shl(96, from)
let from_ := shr(96, shl(96, from))
let to_ := shr(96, shl(96, to))
let slot_seed := shl(224, _BALANCE_SLOT_SEED)
// Compute the balance slot and load its value.
mstore(0x0c, or(from_, _BALANCE_SLOT_SEED))
let fromBalanceSlot := keccak256(0x0c, 0x20)
let fromBalanceSlot := or(slot_seed, from_)
let fromBalance := sload(fromBalanceSlot)
// Revert if insufficient balance.
if gt(amount, fromBalance) {
Expand All @@ -573,15 +571,14 @@ abstract contract ERC20 {
// Subtract and store the updated balance.
sstore(fromBalanceSlot, sub(fromBalance, amount))
// Compute the balance slot of `to`.
mstore(0x00, to)
let toBalanceSlot := keccak256(0x0c, 0x20)
let toBalanceSlot := or(slot_seed, to_)
// Add and store the updated balance of `to`.
// Will not overflow because the sum of all user balances
// cannot exceed the maximum uint256 value.
sstore(toBalanceSlot, add(sload(toBalanceSlot), amount))
// Emit the {Transfer} event.
mstore(0x20, amount)
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, shr(96, from_), shr(96, mload(0x0c)))
log3(0x20, 0x20, _TRANSFER_EVENT_SIGNATURE, from_, to_)
}
_afterTokenTransfer(from, to, amount);
}
Expand Down
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