solidity-gas-optimization

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Solidity Gas Optimization

Solidity Gas优化

Overview

概述

Comprehensive gas optimization guide for Solidity smart contracts, containing 80+ techniques across 8 categories. Based on the RareSkills Book of Gas Optimization. Rules are prioritized by impact and safety.

这是一份全面的Solidity智能合约Gas优化指南，包含8个类别下的80余种优化技巧。基于RareSkills的《Gas优化手册》编写，规则按影响程度和安全性排序。

When to Apply

适用场景

Reference these guidelines when:

Writing new Solidity smart contracts
Reviewing or auditing existing contracts
Optimizing gas costs for deployment or execution
Refactoring contract storage layouts
Implementing cross-contract interactions
Choosing between design patterns (ERC721 vs ERC1155, etc.)

在以下场景中可参考本指南：

编写新的Solidity智能合约时
评审或审计现有合约时
优化部署或执行的Gas成本时
重构合约存储布局时
实现跨合约交互时
在设计模式间做选择时（如ERC721与ERC1155等）

Priority-Ordered Categories

按优先级排序的类别

Priority	Category	Impact	Risk
1	Storage Optimization	CRITICAL	LOW
2	Deployment Optimization	HIGH	LOW
3	Calldata Optimization	HIGH	LOW
4	Design Patterns	HIGH	MEDIUM
5	Cross-Contract Calls	MEDIUM-HIGH	MEDIUM
6	Compiler Optimizations	MEDIUM	LOW
7	Assembly Tricks	MEDIUM	HIGH
8	Dangerous Techniques	LOW	CRITICAL

优先级	类别	影响程度	风险程度
1	存储优化	极高	低
2	部署优化	高	低
3	调用数据优化	高	低
4	设计模式	高	中
5	跨合约调用	中高	中
6	编译器优化	中	低
7	汇编技巧	中	高
8	危险技巧	低	极高

Quick Reference

快速参考

Critical: Storage Optimization (Apply First)

极高优先级：存储优化（优先应用）

Zero-to-One Writes:

Avoid zero-to-one storage writes (costs 22,100 gas)
Use 1/2 instead of 0/1 for boolean-like values
Keep minimum balances in ERC20 contracts

Variable Packing:

solidity

// Bad: 3 slots
struct Unpacked {
    uint64 time;      // slot 1
    uint256 amount;   // slot 2
    address user;     // slot 3
}

// Good: 2 slots
struct Packed {
    uint64 time;      // slot 1 (with address)
    address user;     // slot 1
    uint256 amount;   // slot 2
}

Caching:

solidity

// Bad: reads storage twice
function increment() public {
    require(count < 10);
    count = count + 1;
}

// Good: reads storage once
function increment() public {
    uint256 _count = count;
    require(_count < 10);
    count = _count + 1;
}

Constants & Immutables:

solidity

uint256 constant MAX = 100;        // No storage slot
address immutable owner;           // Set in constructor, no storage

零到一写入优化：

避免零到一的存储写入（成本为22,100 Gas）
用1/2替代0/1来表示类布尔值
在ERC20合约中保留最低余额

变量打包：

solidity

// 糟糕：占用3个存储槽
struct Unpacked {
    uint64 time;      // 槽1
    uint256 amount;   // 槽2
    address user;     // 槽3
}

// 良好：占用2个存储槽
struct Packed {
    uint64 time;      // 槽1（与address共用）
    address user;     // 槽1
    uint256 amount;   // 槽2
}

缓存优化：

solidity

// 糟糕：读取存储两次
function increment() public {
    require(count < 10);
    count = count + 1;
}

// 良好：读取存储一次
function increment() public {
    uint256 _count = count;
    require(_count < 10);
    count = _count + 1;
}

常量与不可变变量：

solidity

uint256 constant MAX = 100;        // 不占用存储槽
address immutable owner;           // 在构造函数中设置，不占用存储

High: Deployment Optimization

高优先级：部署优化

Custom Errors:

solidity

// Bad: ~64+ bytes
require(amount <= limit, "Amount exceeds limit");

// Good: ~4 bytes
error ExceedsLimit();
if (amount > limit) revert ExceedsLimit();

Payable Constructors:

solidity

// Saves ~200 gas on deployment
constructor() payable {}

Clone Patterns:

Use EIP-1167 minimal proxies for repeated deployments
Use UUPS over Transparent Proxy for upgradeable contracts

自定义错误：

solidity

// 糟糕：约占用64+字节
require(amount <= limit, "Amount exceeds limit");

// 良好：约占用4字节
error ExceedsLimit();
if (amount > limit) revert ExceedsLimit();

可支付构造函数：

solidity

// 部署时节省约200 Gas
constructor() payable {}

克隆模式：

对于重复部署，使用EIP-1167最小代理
对于可升级合约，优先使用UUPS而非透明代理

High: Calldata Optimization

高优先级：调用数据优化

Calldata vs Memory:

solidity

// Bad: copies to memory
function process(bytes memory data) external {}

// Good: reads directly from calldata
function process(bytes calldata data) external {}

Avoid Signed Integers:

Small negative numbers are expensive (e.g., -1 = 0xffff...)
Use unsigned integers in function parameters

Calldata与Memory对比：

solidity

// 糟糕：复制到内存
function process(bytes memory data) external {}

// 良好：直接从calldata读取
function process(bytes calldata data) external {}

避免使用有符号整数：

小的负数成本很高（例如：-1 = 0xffff...）
在函数参数中使用无符号整数

High: Design Patterns

高优先级：设计模式

Token Standards:

Prefer ERC1155 over ERC721 for NFTs (no balanceOf overhead)
Consider consolidating multiple ERC20s into one ERC1155

Signature vs Merkle:

Prefer ECDSA signatures over Merkle trees for allowlists
Implement ERC20Permit for approve + transfer in one tx

Alternative Libraries:

Consider Solmate/Solady over OpenZeppelin for gas efficiency

代币标准：

对于NFT，优先选择ERC1155而非ERC721（无balanceOf开销）
考虑将多个ERC20合并为一个ERC1155

签名与默克尔树对比：

对于白名单，优先选择ECDSA签名而非默克尔树
实现ERC20Permit，将approve与transfer合并为一笔交易

替代库选择：

为了Gas效率，考虑使用Solmate/Solady替代OpenZeppelin

Medium-High: Cross-Contract Calls

中高优先级：跨合约调用

Reduce Interactions:

Use ERC1363 transferAndCall instead of approve + transferFrom
Implement multicall for batching operations
Cache external call results (e.g., Chainlink oracles)

Access Lists:

Use ERC2930 access list transactions to pre-warm storage

减少交互次数：

使用ERC1363的transferAndCall替代approve + transferFrom
实现multicall来批量操作
缓存外部调用结果（如Chainlink预言机）

访问列表：

使用ERC2930访问列表交易来预加载存储

Medium: Compiler Optimizations

中优先级：编译器优化

Loop Patterns:

solidity

// Good: unchecked increment, cached length
uint256 len = arr.length;
for (uint256 i; i < len; ) {
    // logic
    unchecked { ++i; }
}

Named Returns:

solidity

// More efficient bytecode
function calc(uint256 x) pure returns (uint256 result) {
    result = x * 2;
}

Bitshifting:

solidity

// Cheaper: 3 gas
x << 1   // x * 2
x >> 2   // x / 4

// Expensive: 5 gas
x * 2
x / 4

Short-Circuit Booleans:

Place likely-to-fail conditions first in
```
&&
```
Place likely-to-succeed conditions first in
```
||
```

循环模式：

solidity

// 良好：无检查递增，缓存长度
uint256 len = arr.length;
for (uint256 i; i < len; ) {
    // 逻辑代码
    unchecked { ++i; }
}

命名返回值：

solidity

// 字节码更高效
function calc(uint256 x) pure returns (uint256 result) {
    result = x * 2;
}

位运算替代乘除：

solidity

// 低成本：3 Gas
x << 1   // x * 2
x >> 2   // x / 4

// 高成本：5 Gas
x * 2
x / 4

布尔短路优化：

在
```
&&
```
中，将可能失败的条件放在前面
在
```
||
```
中，将可能成功的条件放在前面

Medium: Assembly (Use Carefully)

中优先级：汇编（谨慎使用）

Efficient Checks:

solidity

// Check address(0) with assembly
assembly {
    if iszero(caller()) { revert(0, 0) }
}

// Even/odd check
x & 1  // instead of x % 2

Memory Reuse:

Reuse scratch space (0x00-0x40) for small operations
Avoid memory expansion in loops

高效检查：

solidity

// 用汇编检查address(0)
assembly {
    if iszero(caller()) { revert(0, 0) }
}

// 奇偶检查
x & 1  // 替代x % 2

内存复用：

复用临时空间（0x00-0x40）用于小型操作
避免在循环中扩展内存

Avoid: Dangerous Techniques

需避免：危险技巧

These are unsafe for production:

Making all functions payable
Ignoring send() return values
Using gasleft() for branching
Manipulating block.number in tests

这些技巧在生产环境中不安全：

将所有函数设为payable
忽略send()的返回值
使用gasleft()进行分支判断
在测试中操纵block.number

Outdated Patterns

已过时的模式

These no longer apply in modern Solidity:

"external is cheaper than public" - No longer true
"!= 0 is cheaper than > 0" - Changed around 0.8.12

这些模式在现代Solidity中不再适用：

"external比public更便宜" - 已不再成立
"!=0比>0更便宜" - 在0.8.12左右发生了变化

References

参考资料

Full documentation with code examples:

```
references/solidity-gas-guidelines.md
```
- Complete guide
```
references/rules/
```
- Individual patterns by category

To look up specific patterns:

bash

grep -l "storage" references/rules/
grep -l "assembly" references/rules/
grep -l "struct" references/rules/

包含代码示例的完整文档：

```
references/solidity-gas-guidelines.md
```
- 完整指南
```
references/rules/
```
- 按类别划分的单个模式

查找特定模式的方法：

bash

grep -l "storage" references/rules/
grep -l "assembly" references/rules/
grep -l "struct" references/rules/

Rule Categories in

references/rules/

references/rules/

中的规则类别

```
storage-*
```
- Storage optimization patterns
```
deploy-*
```
- Deployment gas savings
```
calldata-*
```
- Calldata optimization
```
design-*
```
- Design pattern choices
```
crosscall-*
```
- Cross-contract call optimization
```
compiler-*
```
- Compiler optimization patterns
```
assembly-*
```
- Low-level assembly tricks

```
storage-*
```
- 存储优化模式
```
deploy-*
```
- 部署Gas节省技巧
```
calldata-*
```
- 调用数据优化
```
design-*
```
- 设计模式选择
```
crosscall-*
```
- 跨合约调用优化
```
compiler-*
```
- 编译器优化模式
```
assembly-*
```
- 底层汇编技巧

Key Principles

核心原则

Always Benchmark - Compiler behavior varies by context and version
Balance Readability - Not all optimizations are worth code complexity
Test Both Approaches - Counterintuitive optimizations sometimes increase costs
Consider
--via-ir
- Modern compiler option may obsolete some tricks
Use Alternative Libraries - Solmate/Solady often beat OpenZeppelin on gas

始终进行基准测试 - 编译器行为会因上下文和版本而异
平衡可读性 - 并非所有优化都值得牺牲代码复杂度
测试两种实现方式 - 违反直觉的优化有时会增加成本
考虑使用
--via-ir
- 现代编译器选项可能会使某些技巧过时
使用替代库 - Solmate/Solady在Gas效率上通常优于OpenZeppelin

solidity-gas-optimization

Original

Translation

Solidity Gas Optimization

Solidity Gas优化

Overview

概述

When to Apply

适用场景

Priority-Ordered Categories

按优先级排序的类别

Quick Reference

快速参考

Critical: Storage Optimization (Apply First)

极高优先级：存储优化（优先应用）

High: Deployment Optimization

高优先级：部署优化

High: Calldata Optimization

高优先级：调用数据优化

High: Design Patterns

高优先级：设计模式

Medium-High: Cross-Contract Calls

中高优先级：跨合约调用

Medium: Compiler Optimizations

中优先级：编译器优化

Medium: Assembly (Use Carefully)

中优先级：汇编（谨慎使用）

Avoid: Dangerous Techniques

需避免：危险技巧

Outdated Patterns

已过时的模式

References

参考资料

Rule Categories in
`references/rules/`

`references/rules/`
中的规则类别

Key Principles

核心原则

solidity-gas-optimization

Original

Translation

Solidity Gas Optimization

Solidity Gas优化

Overview

概述

When to Apply

适用场景

Priority-Ordered Categories

按优先级排序的类别

Quick Reference

快速参考

Critical: Storage Optimization (Apply First)

极高优先级：存储优化（优先应用）

High: Deployment Optimization

高优先级：部署优化

High: Calldata Optimization

高优先级：调用数据优化

High: Design Patterns

高优先级：设计模式

Medium-High: Cross-Contract Calls

中高优先级：跨合约调用

Medium: Compiler Optimizations

中优先级：编译器优化

Medium: Assembly (Use Carefully)

中优先级：汇编（谨慎使用）

Avoid: Dangerous Techniques

需避免：危险技巧

Outdated Patterns

已过时的模式

References

参考资料

Rule Categories in references/rules/

references/rules/中的规则类别

Key Principles

核心原则

Rule Categories in
`references/rules/`

`references/rules/`
中的规则类别