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Documented inline assembly functions

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This commit is contained in:
Greg Hysen
2018-12-04 13:37:48 -08:00
parent 0556defa58
commit 3bb147b0f1
2 changed files with 154 additions and 52 deletions
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202
packages/contracts/contracts/extensions/CompliantForwarder/CompliantForwarder.sol
View File

@@ -60,93 +60,193 @@ contract CompliantForwarder is ExchangeSelectors{
// Validate addresses
assembly {
/**
* Emulates the `calldataload` opcode on the embedded Exchange calldata,
* which is accessed through `signedExchangeTransaction`.
* @param offset - Offset into the Exchange calldata.
* @return value - Corresponding 32 byte value stored at `offset`.
*/
function exchangeCalldataload(offset) -> value {
// exchangeTxPtr at global level
// 0x20 for length offset into exchange TX
// 0x4 for function selector in exhcange TX
// Pointer to exchange transaction
// 0x04 for calldata selector
// 0x40 to access `signedExchangeTransaction`, which is the third parameter
let exchangeTxPtr := calldataload(0x44)
let exchangeOffset := add(exchangeTxPtr, add(0x24, offset))
value := calldataload(exchangeOffset)
// Offset into Exchange calldata
// We compute this by adding 0x24 to the `exchangeTxPtr` computed above.
// 0x04 for calldata selector
// 0x20 for length field of `signedExchangeTransaction`
let exchangeCalldataOffset := add(exchangeTxPtr, add(0x24, offset))
value := calldataload(exchangeCalldataOffset)
}
/**
* Convenience function that skips the 4 byte selector when loading
* from the embedded Exchange calldata.
* @param offset - Offset into the Exchange calldata (minus the 4 byte selector)
* @return value - Corresponding 32 byte value stored at `offset` + 4.
*/
function loadExchangeData(offset) -> value {
value := exchangeCalldataload(add(offset, 0x4))
}
// Adds address to validate
function addAddressToValidate(addressToValidate) {
// Compute `addressesToValidate` memory location
/**
* A running list is maintained of addresses to validate.
* This function records an address in this array.
* @param addressToValidate - Address to record for validation.
* @note - Variables are scoped but names are not, so we append
* underscores to names that share the global namespace.
*/
function recordAddressToValidate(addressToValidate) {
// Compute `addressesToValidate` memory offset
let addressesToValidate_ := mload(0x40)
let nAddressesToValidate_ := mload(addressesToValidate_)
// Increment length
nAddressesToValidate_ := add(mload(addressesToValidate_), 1)
nAddressesToValidate_ := add(mload(addressesToValidate_), 0x01)
mstore(addressesToValidate_, nAddressesToValidate_)
// Append address to validate
let offset := mul(32, nAddressesToValidate_)
let offset := mul(nAddressesToValidate_, 0x20)
mstore(add(addressesToValidate_, offset), addressToValidate)
}
function appendMakerAddressFromOrder(orderParamIndex) {
let orderPtr := loadExchangeData(0)
/**
* Extracts the maker address from an order stored in the Exchange calldata
* (which is embedded in `signedExchangeTransaction`), and records it in
* the running list of addresses to validate.
* @param orderParamIndex - Index of the order in the Exchange function's signature
*/
function recordMakerAddressFromOrder(orderParamIndex) {
let orderPtr := loadExchangeData(orderParamIndex)
let makerAddress := loadExchangeData(orderPtr)
addAddressToValidate(makerAddress)
recordAddressToValidate(makerAddress)
}
function appendMakerAddressesFromOrderSet(orderSetParamIndex) {
let orderSetPtr := loadExchangeData(0)
let orderSetLength := loadExchangeData(orderSetPtr)
let orderSetElementPtr := add(orderSetPtr, 0x20)
let orderSetElementEndPtr := add(orderSetElementPtr, mul(orderSetLength, 0x20))
for {let orderPtrOffset := orderSetElementPtr} lt(orderPtrOffset, orderSetElementEndPtr) {orderPtrOffset := add(orderPtrOffset, 0x20)} {
/**
* Extracts the maker addresses from an array of orders stored in the Exchange calldata
* (which is embedded in `signedExchangeTransaction`), and records them in
* the running list of addresses to validate.
* @param orderArrayParamIndex - Index of the order array in the Exchange function's signature
*/
function recordMakerAddressesFromOrderArray(orderArrayParamIndex) {
let orderArrayPtr := loadExchangeData(0x0)
let orderArrayLength := loadExchangeData(orderArrayPtr)
let orderArrayElementPtr := add(orderArrayPtr, 0x20)
let orderArrayElementEndPtr := add(orderArrayElementPtr, mul(orderArrayLength, 0x20))
for {let orderPtrOffset := orderArrayElementPtr} lt(orderPtrOffset, orderArrayElementEndPtr) {orderPtrOffset := add(orderPtrOffset, 0x20)} {
let orderPtr := loadExchangeData(orderPtrOffset)
let makerAddress := loadExchangeData(add(orderPtr, orderSetElementPtr))
addAddressToValidate(makerAddress)
let makerAddress := loadExchangeData(add(orderPtr, orderArrayElementPtr))
recordAddressToValidate(makerAddress)
}
}
// Extract addresses to validate
let selector := and(
exchangeCalldataload(0),
/**
* Records address of signer in the running list of addresses to validate.
* @note: We cannot access `signerAddress` directly from within the asm function,
* so it is loaded from the calldata.
*/
function recordSignerAddress() {
// Load the signer address from calldata
// 0x04 for selector
// 0x20 to access `signerAddress`, which is the second parameter.
let signerAddress_ := calldataload(0x24)
recordAddressToValidate(signerAddress_)
}
/**
* Records addresses to be validated when Exchange transaction is a batch fill variant.
* This is one of: batchFillOrders, batchFillOrKillOrders, batchFillNoThrow
* Reference signature<T>: <batchFillVariant>(Order[],uint256[],bytes[])
*/
function recordAddressesForBatchFillVariant() {
// Record maker addresses from order array (parameter index 0)
// The signer is the taker for these orders and must also be validated.
recordMakerAddressesFromOrderArray(0)
recordSignerAddress()
}
/**
* Records addresses to be validated when Exchange transaction is a fill order variant.
* This is one of: fillOrder, fillOrKillOrder, fillOrderNoThrow
* Reference signature<T>: <fillOrderVariant>(Order,uint256,bytes)
*/
function recordAddressesForFillOrderVariant() {
// Record maker address from the order (param index 0)
// The signer is the taker for this order and must also be validated.
recordMakerAddressFromOrder(0)
recordSignerAddress()
}
/**
* Records addresses to be validated when Exchange transaction is a market fill variant.
* This is one of: marketBuyOrders, marketBuyOrdersNoThrow, marketSellOrders, marketSellOrdersNoThrow
* Reference signature<T>: <marketFillInvariant>(Order[],uint256,bytes[])
*/
function recordAddressesForMarketFillVariant() {
// Record maker addresses from order array (parameter index 0)
// The signer is the taker for these orders and must also be validated.
recordMakerAddressesFromOrderArray(0)
recordSignerAddress()
}
/**
* Records addresses to be validated when Exchange transaction is matchOrders.
* Reference signature: matchOrders(Order,Order)
*/
function recordAddressesForMatchOrders() {
// Record maker address from both orders (param indices 0 & 1).
// The signer is the taker and must also be validated.
recordMakerAddressFromOrder(0)
recordMakerAddressFromOrder(1)
recordSignerAddress()
}
///// Record Addresses to Validate /////
// Addresses needing validation depends on which Exchange function is being called.
// Step 1/2 Read the exchange function selector.
let exchangeFunctionSelector := and(
exchangeCalldataload(0x0),
0xffffffff00000000000000000000000000000000000000000000000000000000
)
switch selector
case 0x297bb70b00000000000000000000000000000000000000000000000000000000 /* batchFillOrders */
{
appendMakerAddressesFromOrderSet(0)
addAddressToValidate(signerAddress)
}
case 0x3c28d86100000000000000000000000000000000000000000000000000000000 /* matchOrders */
{
// appendMakerAddressFromOrder(0)
//// appendMakerAddressFromOrder(1)
// addAddressToValidate(signerAddress)
}
case 0xb4be83d500000000000000000000000000000000000000000000000000000000 /* fillOrder */
{
appendMakerAddressFromOrder(0)
addAddressToValidate(signerAddress)
}
case 0xd46b02c300000000000000000000000000000000000000000000000000000000 /* cancelOrder */ {}
// Step 2/2 Extract addresses to validate based on this selector.
// See ../../utils/ExchangeSelectors/ExchangeSelectors.sol for selectors
switch exchangeFunctionSelector
case 0x297bb70b00000000000000000000000000000000000000000000000000000000 { recordAddressesForBatchFillVariant() } // batchFillOrders
case 0x50dde19000000000000000000000000000000000000000000000000000000000 { recordAddressesForBatchFillVariant() } // batchFillOrdersNoThrow
case 0x4d0ae54600000000000000000000000000000000000000000000000000000000 { recordAddressesForBatchFillVariant() } // batchFillOrKillOrders
case 0xb4be83d500000000000000000000000000000000000000000000000000000000 { recordAddressesForFillOrderVariant() } // fillOrder
case 0x3e228bae00000000000000000000000000000000000000000000000000000000 { recordAddressesForFillOrderVariant() } // fillOrderNoThrow
case 0x64a3bc1500000000000000000000000000000000000000000000000000000000 { recordAddressesForFillOrderVariant() } // fillOrKillOrder
case 0xe5fa431b00000000000000000000000000000000000000000000000000000000 { recordAddressesForMarketFillVariant() } // marketBuyOrders
case 0xa3e2038000000000000000000000000000000000000000000000000000000000 { recordAddressesForMarketFillVariant() } // marketBuyOrdersNoThrow
case 0x7e1d980800000000000000000000000000000000000000000000000000000000 { recordAddressesForMarketFillVariant() } // marketSellOrders
case 0xdd1c7d1800000000000000000000000000000000000000000000000000000000 { recordAddressesForMarketFillVariant() } // marketSellOrdersNoThrow
case 0x3c28d86100000000000000000000000000000000000000000000000000000000 { recordAddressesForMatchOrders() } // matchOrders
case 0xd46b02c300000000000000000000000000000000000000000000000000000000 {} // cancelOrder
case 0x4ac1478200000000000000000000000000000000000000000000000000000000 {} // batchCancelOrders
case 0x4f9559b100000000000000000000000000000000000000000000000000000000 {} // cancelOrdersUpTo
default {
revert(0, 100)
}
// Load addresses to validate from memory
///// Validate Recorded Addresses /////
// Load from memory the addresses to validate
let addressesToValidate := mload(0x40)
let addressesToValidateLength := mload(addressesToValidate)
let addressesToValidateElementPtr := add(addressesToValidate, 0x20)
let addressesToValidateElementEndPtr := add(addressesToValidateElementPtr, mul(addressesToValidateLength, 0x20))
// Record new free memory pointer to after `addressesToValidate` array
// Set free memory pointer to after `addressesToValidate` array.
// This is to avoid corruption when making calls in the loop below.
let freeMemPtr := addressesToValidateElementEndPtr
mstore(0x40, freeMemPtr)
// Validate addresses
let complianceTokenAddress := sload(COMPLIANCE_TOKEN_slot)
for {let addressToValidate := addressesToValidateElementPtr} lt(addressToValidate, addressesToValidateElementEndPtr) {addressToValidate := add(addressToValidate, 0x20)} {
// Construct calldata for `COMPLIANCE_TOKEN.balanceOf`
mstore(freeMemPtr, 0x70a0823100000000000000000000000000000000000000000000000000000000)
@@ -171,11 +271,11 @@ contract CompliantForwarder is ExchangeSelectors{
let addressBalance := mload(freeMemPtr)
if eq(addressBalance, 0) {
// Revert with `Error("AT_LEAST_ONE_ADDRESS_HAS_ZERO_BALANCE")`
/*mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
mstore(64, 0x0000002541545f4c454153545f4f4e455f414444524553535f4841535f5a4552)
mstore(96, 0x4f5f42414c414e43450000000000000000000000000000000000000000000000)
revert(0, 109)*/
revert(0, 109)
}
}
@@ -183,14 +283,16 @@ contract CompliantForwarder is ExchangeSelectors{
validatedAddresses := addressesToValidate
}
///// If we hit this point then all addresses are valid /////
emit ValidatedAddresses(validatedAddresses);
// All entities are verified. Execute fillOrder.
/* EXCHANGE.executeTransaction(
// All addresses are valid. Execute fillOrder.
EXCHANGE.executeTransaction(
salt,
signerAddress,
signedExchangeTransaction,
signature
);*/
);
}
}

4
packages/contracts/test/extensions/compliant_forwarder.ts
View File

@@ -206,7 +206,7 @@ describe.only(ContractName.CompliantForwarder, () => {
afterEach(async () => {
await blockchainLifecycle.revertAsync();
});
describe('fillOrder', () => {
describe.only('fillOrder', () => {
beforeEach(async () => {
erc20Balances = await erc20Wrapper.getBalancesAsync();
});
@@ -336,7 +336,7 @@ describe.only(ContractName.CompliantForwarder, () => {
});
});
describe.only('batchFillOrders', () => {
describe('batchFillOrders', () => {
beforeEach(async () => {
erc20Balances = await erc20Wrapper.getBalancesAsync();
});