SolidityとVyperのコンパイル戦略

概要

Solidityの方がVyperより複雑なコンパイルの仕方をする

結論は、Vyperと異なるコンパイル戦略を取っていること

何のためのSWAP?

代入のみ

In Solidity(say ver0.4.18) , when I compiled this code:

code: Solidity

pragma solidity ^0.4.18;

contract C {

uint256 data;

function C() public {

data = 123;

}

}

the assembly part of data = 123 is

PUSH1 0x7B PUSH1 0x0 DUP2 SWAP1 SSTORE POP

In Vyper, when I compiled the code below

code: Vyper(Python)

data: public(uint256)

@public

def __init__():

self.data = 123

the assembly part of self.data = 123 is

PUSH1 0x7B PUSH1 0x00 SSTORE

変数での代入

code: Solidity

pragma solidity ^0.4.18;

contract C {

uint256 data;

function C() public {

uint256 a = 123;

data = a;

}

}

PUSH1 0x0 PUSH1 0x7B SWAP1 POP DUP1 PUSH1 0x0 DUP2 SWAP1 SSTORE POP POP

code: Vyper

data: public(uint256)

@public

def __init__():

a: uint256 = 123

self.data = a

PUSH1 0x7b PUSH2 0x0140 MSTORE PUSH2 0x0140 MLOAD PUSH1 0x00 SSTORE PUSH2 0x016f

変数での代入、直後再代入

code: Solidity

pragma solidity ^0.4.18;

contract C {

uint256 data;

function C() public {

uint256 a = 123;

data = a;

a = 456;

}

}

code: EVM

PUSH1 0x0 PUSH1 0x7B SWAP1 POP (→stack: 0x7B )

DUP1 PUSH1 0x0 DUP2 SWAP1 SSTORE (→stack: 0x7B 0x7B)

POP PUSH2 0x1C8 SWAP1 POP POP

ストレージに入れる値はいつもスタック先頭に残されるっぽい

code: Vyper(Python)

data: public(uint256)

@public

def __init__():

a: uint256 = 123

self.data = a

a = 456

code: EVM

009F 60 PUSH1 0x7b

00A1 61 PUSH2 0x0140

00A4 52 MSTORE

00A5 61 PUSH2 0x0140

00A8 51 MLOAD

00A9 60 PUSH1 0x00

00AB 55 SSTORE

00AC 61 PUSH2 0x016f

代入する変数を直後で利用

code: Solidity

pragma solidity ^0.4.18;

contract C {

uint256 data;

uint256 data2;

function C() public {

uint256 a = 123;

data = a;

data2 = a;

}

}

code: EVM

PUSH1 0x0 PUSH1 0x7B SWAP1 POP DUP1 PUSH1 0x0 (stack: 0x0 07B 07B)

DUP2 SWAP1 (stack: 0x0 07B 07B 07B)

SSTORE POP DUP1 PUSH1 0x1 DUP2 SWAP1 SSTORE POP POP

code: Vyper(Python)

data: public(uint256)

data2: public(uint256)

@public

def __init__():

a: uint256 = 123

self.data = a

self.data2 = a

code: EVM

PUSH1 0x7b PUSH2 0x0140 MSTORE PUSH2 0x0140 MLOAD PUSH1 0x00 SSTORE PUSH2 0x0140 MLOAD PUSH1 0x01 SSTORE PUSH2 0x019c *JUMP

ORの計算方法

code: simpleOR.vy(Python)

@public

def simpleOR(a: bool, b: bool) -> bool:

return a or b

OR

code: simpleOR.sol(Javascript)

pragma solidity ^0.5.1;

contract Test {

function simpleOR(bool a, bool b) public returns(bool) {

return a || b;

}

}