Optimizer in solidity

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Optimizer in solidity

  • 合约设计及实现变迁

    v1.x版本实现，每次创建同样的合约


    v2.x版本实现, 逻辑单独抽象成library,每次创建合约仅包含storage variables


    v3.x版本实现, 分为代理合约和逻辑合约,每次创建代理合约（不包含逻辑和storage variables)


    summary: 如果某个合约需要部署很多次，可以采用library或proxy来部署合约，每个合约仅是初始化值不同，采用proxy模式更好

    contract Table is Proxy {

    bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    constructor(
        address _implAddr
    ) {
        _setImplementation(_implAddr);
    }

    function _implementation() internal view override returns (address) {
        return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }

    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
        StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
    }

}

constract Logic {
}

    contract Table {
    using TableLogic for TableLogic.TableInfo;
    TableLogic.TableInfo tableInfo;
}

library TableLogic {
}

  • solidity中的optimizer

    大部分论述来自 https://docs.soliditylang.org/en/v0.8.17/internals/optimizer.html

    solidity使用两种编译器:The opcode-based optimizer 和 The Yul-based optimizer.

    solidity产生EVM bytecode有两种方式: solidity语言直接翻译成evm opcode, 或先翻译成Yul后再翻译成evm opcode(IR-based code generator).

    The IR-based code generator不仅更透明和可审计的，而且可以跨函数优化code。同样的solidity代码可能产生不同的语义变化( https://docs.soliditylang.org/en/v0.8.17/ir-breaking-changes.html) .

    • The opcode-based optimizer

      这个优化器主要是简化相同的代码，删除无用的代码. 简化规则参考( https://github.com/ethereum/solidity/blob/develop/libevmasm/RuleList.h )

    • The Yul-based optimizer

    • Optimizer Parameter Runs

      这个参数指定了部署代码在合约生命周期内执行的频率，是code size(deploy cost)和code execution(cost after deployment)的权衡

      参数范围: [1, 2^32-1]

    • 使用编译器配置

      "optimizer": {
  // Disabled by default.
  // NOTE: enabled=false still leaves some optimizations on. See comments below.
  // WARNING: Before version 0.8.6 omitting the 'enabled' key was not equivalent to setting
  // it to false and would actually disable all the optimizations.
  "enabled": true,
  // Optimize for how many times you intend to run the code.
  // Lower values will optimize more for initial deployment cost, higher
  // values will optimize more for high-frequency usage.
  "runs": 200,
  // Switch optimizer components on or off in detail.
  // The "enabled" switch above provides two defaults which can be
  // tweaked here. If "details" is given, "enabled" can be omitted.
  "details": {
    // The peephole optimizer is always on if no details are given,
    // use details to switch it off.
    "peephole": true,
    // The inliner is always on if no details are given,
    // use details to switch it off.
    "inliner": true,
    // The unused jumpdest remover is always on if no details are given,
    // use details to switch it off.
    "jumpdestRemover": true,
    // Sometimes re-orders literals in commutative operations.
    "orderLiterals": false,
    // Removes duplicate code blocks
    "deduplicate": false,
    // Common subexpression elimination, this is the most complicated step but
    // can also provide the largest gain.
    "cse": false,
    // Optimize representation of literal numbers and strings in code.
    "constantOptimizer": false,
    // The new Yul optimizer. Mostly operates on the code of ABI coder v2
    // and inline assembly.
    // It is activated together with the global optimizer setting
    // and can be deactivated here.
    // Before Solidity 0.6.0 it had to be activated through this switch.
    "yul": false,
    // Tuning options for the Yul optimizer.
    "yulDetails": {
      // Improve allocation of stack slots for variables, can free up stack slots early.
      // Activated by default if the Yul optimizer is activated.
      "stackAllocation": true,
      // Select optimization steps to be applied.
      // Optional, the optimizer will use the default sequence if omitted.
      "optimizerSteps": "dhfoDgvulfnTUtnIf..."
    }
  }
}

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