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vm: simplify error handling in vm.EVM.create() (#30292)
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To allow all error paths in `vm.EVM.create()` to consume the necessary
gas, there is currently a pattern of gating code on `if err == nil`
instead of returning as soon as the error occurs. The same behaviour can
be achieved by abstracting the gated code into a method that returns
immediately on error, improving readability and thus making it easier to
understand and maintain.
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ARR4N authored Aug 16, 2024
1 parent 09d889d commit 710c3f3
Showing 1 changed file with 34 additions and 39 deletions.
73 changes: 34 additions & 39 deletions core/vm/evm.go
Original file line number Diff line number Diff line change
Expand Up @@ -510,64 +510,59 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
contract.SetCodeOptionalHash(&address, codeAndHash)
contract.IsDeployment = true

ret, err = evm.initNewContract(contract, address, value)
if err != nil && (evm.chainRules.IsHomestead || err != ErrCodeStoreOutOfGas) {
evm.StateDB.RevertToSnapshot(snapshot)
if err != ErrExecutionReverted {
contract.UseGas(contract.Gas, evm.Config.Tracer, tracing.GasChangeCallFailedExecution)
}
}
return ret, address, contract.Gas, err
}

// initNewContract runs a new contract's creation code, performs checks on the
// resulting code that is to be deployed, and consumes necessary gas.
func (evm *EVM) initNewContract(contract *Contract, address common.Address, value *uint256.Int) ([]byte, error) {
// Charge the contract creation init gas in verkle mode
if evm.chainRules.IsEIP4762 {
if !contract.UseGas(evm.AccessEvents.ContractCreateInitGas(address, value.Sign() != 0), evm.Config.Tracer, tracing.GasChangeWitnessContractInit) {
err = ErrOutOfGas
return nil, ErrOutOfGas
}
}

if err == nil {
ret, err = evm.interpreter.Run(contract, nil, false)
ret, err := evm.interpreter.Run(contract, nil, false)
if err != nil {
return ret, err
}

// Check whether the max code size has been exceeded, assign err if the case.
if err == nil && evm.chainRules.IsEIP158 && len(ret) > params.MaxCodeSize {
err = ErrMaxCodeSizeExceeded
if evm.chainRules.IsEIP158 && len(ret) > params.MaxCodeSize {
return ret, ErrMaxCodeSizeExceeded
}

// Reject code starting with 0xEF if EIP-3541 is enabled.
if err == nil && len(ret) >= 1 && ret[0] == 0xEF && evm.chainRules.IsLondon {
err = ErrInvalidCode
}

// if the contract creation ran successfully and no errors were returned
// calculate the gas required to store the code. If the code could not
// be stored due to not enough gas set an error and let it be handled
// by the error checking condition below.
if err == nil {
if !evm.chainRules.IsEIP4762 {
createDataGas := uint64(len(ret)) * params.CreateDataGas
if !contract.UseGas(createDataGas, evm.Config.Tracer, tracing.GasChangeCallCodeStorage) {
err = ErrCodeStoreOutOfGas
}
} else {
// Contract creation completed, touch the missing fields in the contract
if !contract.UseGas(evm.AccessEvents.AddAccount(address, true), evm.Config.Tracer, tracing.GasChangeWitnessContractCreation) {
err = ErrCodeStoreOutOfGas
}
if len(ret) >= 1 && ret[0] == 0xEF && evm.chainRules.IsLondon {
return ret, ErrInvalidCode
}

if err == nil && len(ret) > 0 && !contract.UseGas(evm.AccessEvents.CodeChunksRangeGas(address, 0, uint64(len(ret)), uint64(len(ret)), true), evm.Config.Tracer, tracing.GasChangeWitnessCodeChunk) {
err = ErrCodeStoreOutOfGas
}
if !evm.chainRules.IsEIP4762 {
createDataGas := uint64(len(ret)) * params.CreateDataGas
if !contract.UseGas(createDataGas, evm.Config.Tracer, tracing.GasChangeCallCodeStorage) {
return ret, ErrCodeStoreOutOfGas
}

if err == nil {
evm.StateDB.SetCode(address, ret)
} else {
// Contract creation completed, touch the missing fields in the contract
if !contract.UseGas(evm.AccessEvents.AddAccount(address, true), evm.Config.Tracer, tracing.GasChangeWitnessContractCreation) {
return ret, ErrCodeStoreOutOfGas
}
}

// When an error was returned by the EVM or when setting the creation code
// above we revert to the snapshot and consume any gas remaining. Additionally,
// when we're in homestead this also counts for code storage gas errors.
if err != nil && (evm.chainRules.IsHomestead || err != ErrCodeStoreOutOfGas) {
evm.StateDB.RevertToSnapshot(snapshot)
if err != ErrExecutionReverted {
contract.UseGas(contract.Gas, evm.Config.Tracer, tracing.GasChangeCallFailedExecution)
if len(ret) > 0 && !contract.UseGas(evm.AccessEvents.CodeChunksRangeGas(address, 0, uint64(len(ret)), uint64(len(ret)), true), evm.Config.Tracer, tracing.GasChangeWitnessCodeChunk) {
return ret, ErrCodeStoreOutOfGas
}
}

return ret, address, contract.Gas, err
evm.StateDB.SetCode(address, ret)
return ret, nil
}

// Create creates a new contract using code as deployment code.
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