Solidity for NEAR

We present a prototype of a toolchain for compiling Ethereum Virtual Machine (EVM) smart contracts into WebAssembly bytecode for NEAR, and discuss future directions to incorporate this functionality directly into Aurora Engine.

Transcript

1. aurora.dev
   2022-09-13
   Solidity for NEAR
   Arto Bendiken
   

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2. 1. Overview
   2. History
   3. EVM to WebAssembly?
   4. Solidity for NEAR
   5. Future Directions
   Agenda
   

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3. Overview
   

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4. Aurora Engine, an L2 for NEAR Protocol
   Aurora Engine
   (EVM)
   NEAR Runtime
   (WebAssembly)
   NEAR Protocol
   

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5. NEAR Runtime
   (WebAssembly bytecode
   runtime)
   Wasmer
   (WebAssembly→x86-64 JIT)
   SputnikVM
   (EVM bytecode interpreter)
   EVM Interpretation Tower
   x86-64 CPU
   (Intel/AMD μcode JIT)
   

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6. History
   

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7. EVM Optimizations in 2021-2022
   Changes to NEAR Protocol
   ● secp256k1 ecrecover host function
   ● ripemd host function
   ● alt_bn128 host function
   ● Decrease in cost per Wasm op code
   ● Decrease in state access cost (caching
   trie nodes)
   ● Increase the per-transaction gas limit
   Changes to Aurora
   ● Cache state access
   ● Optimize for performance instead of
   code size
   Changes to SputnikVM
   ● Implement SIGNEXTEND, MLOAD, and
   MSTORE more eiciently
   ● Specialize the PUSH1 and PUSH2
   implementations (from generic PUSHN)
   ● Structure the interpreter loop more
   eiciently
   

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8. 11×
   +
   (Single-transaction EVM gas limit 153K → 1.7M)
   

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9. Kudos!
   Contributors from Aurora
   ● Michael Birch (@birchmd)
   ● Joshua Bouw (@joshuajbouw)
   ● Evgeny Ukhanov (@mrLSD)
   Contributors from NEAR
   ● Aleksey Kladov (@matklad)
   ● Nikolay Igoi (@olonho)
   ● Aleksandr Logunov (@longarithm)
   

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10. Good News, Bad News
    Averages from a sample of
    all successful transactions
    

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11. Good News, Bad News
    Averages from a sample
    of expensive (200+ Tgas)
    transactions
    

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12. EVM to WebAssembly?
    

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13. // SPDX-License-Identifier: Unlicense
    pragma solidity ^0.8.16;
    contract Counter {
    int private count = 0;
    function increment() public {
    count += 1;
    }
    function decrement() public {
    count -= 1;
    }
    function get() public view returns (int) {
    return count;
    }
    }
    increment:
    JUMPDEST
    POP
    PUSH1 0x01
    PUSH1 0x00
    SLOAD
    ADD
    DUP1
    PUSH1 0x00
    SSTORE
    PUSH1 0x00
    MSTORE
    PUSH1 0x20
    PUSH1 0x00
    RETURN
    STOP
    EVM to WebAssembly (counter.sol ⇒ counter.sol.asm)
    

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14. increment:
    JUMPDEST
    POP
    PUSH1 0x01
    PUSH1 0x00
    SLOAD
    ADD
    DUP1
    PUSH1 0x00
    SSTORE
    PUSH1 0x00
    MSTORE
    PUSH1 0x20
    PUSH1 0x00
    RETURN
    STOP
    pub fn increment() {
    evm.push1(0x01);
    evm.push1(0x00);
    evm.sload();
    evm.add();
    evm.dup1();
    evm.push1(0x00);
    evm.sstore();
    evm.push1(0x00);
    evm.mstore();
    evm.push1(0x20);
    evm.push1(0x00);
    evm.r#return()
    }
    EVM to WebAssembly (counter.sol.asm ⇒ counter.rs)
    

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15. (func $increment
    i32.const 1
    call $evm/push1
    i32.const 0
    call $evm/push1
    call $evm/sload
    call $evm/add
    call $evm/dup1
    i32.const 0
    call $evm/push1
    call $evm/sstore
    i32.const 0
    call $evm/push1
    increment:
    JUMPDEST
    POP
    PUSH1 0x01
    PUSH1 0x00
    SLOAD
    ADD
    DUP1
    PUSH1 0x00
    SSTORE
    PUSH1 0x00
    MSTORE
    PUSH1 0x20
    PUSH1 0x00
    RETURN
    STOP
    EVM to WebAssembly (counter.sol.asm ⇒ counter.wat)
    call $evm/mstore
    i32.const 32
    call $evm
    i32.const 0
    call $evm
    call $evm/return
    )
    

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16. Solidity for NEAR
    (evm2near)
    

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17. github.com/aurora-is-near/evm2near
    

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18. // SPDX-License-Identifier: Unlicense
    pragma solidity ^0.8.16;
    contract Calc {
    function multiply(int a, int b) public pure returns (int) {
    return a * b;
    }
    }
    

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19. % evm2near test/calc.sol -o test.wasm
    % near dev-deploy test.wasm
    % near view dev-1662780277695-66709124501364 \
    multiply '{"a":6, "b":7}'
    

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20. 15×
    +
    (Benchmark Solidity contract 1500 Tgas → 100 Tgas)
    

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21. Michael Birch (@birchmd)
    Arto Bendiken (@artob)
    The Compiler Team
    

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22. We are hiring Junior and Senior Compiler Engineers
    to join this deep-tech R&D team!
    Apply at auroralabs.dev under “Work at Aurora”
    

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23. Future Directions
    

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24. Expensive instructions
    ● CODECOPY
    Requires embedding a copy of the original
    EVM bytecode into the output (bloat)
    ● PC
    Requires either instrumenting generated
    code for precise program-counter
    accounting (slowdown), or embedding a
    large lookup table into the output (bloat)
    ● GAS
    Requires instrumenting generated code to
    support precise gas accounting
    (slowdown)
    Unimplemented instructions (7)
    ● CREATE
    ● CALL
    ● CALLCODE
    ● DELEGATECALL
    ● CREATE2
    ● STATICCALL
    ● SELFDESTRUCT
    EVM to WebAssembly: Some challenges
    

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25. Immediately past the MVP release
    ● Make EVM gas metering optional for a
    nice speedup when it isn’t required for
    full EVM compatibility
    ● Implement a test suite based on popular
    real-world deployed contracts and
    associated transactions, sanity
    checking that for the same inputs we
    get the same known-good outputs
    (including EVM gas metering)
    Future R&D directions past MVP
    ● Inlining EVM opcode calls for certain
    instructions where that would benefit
    ● Applying other standard compiler
    optimizations from the literature for
    leaner and meaner bytecode
    ● Adding NEAR host functions to beer
    support 256-bit machine words without
    the need for expensive bigint arithmetic
    ● Adding NEAR host functions to speed up
    other aspects of execution, based on
    extensive and convincing profiling
    results
    EVM to WebAssembly: Compiler
    

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26. Dynamically loaded WebAssembly
    embedded inside the Aurora Engine (“JIT”)
    ● Just-in-time compiled WebAssembly
    bytecode automatically deployed to,
    stored in, and maintained by the Aurora
    Engine for “hot” contracts
    ● Trusted-yet-sandboxed bytecode
    deployed reproducibly by trusted parties
    ● Zero EVM compatibility issues, just a
    significant speedup
    ● Requires a NEP process, nearcore
    implementation, and protocol upgrade
    for dynamic bytecode support (6
    months minimum)
    Standalone static NEAR contract
    deployment (“AOT”)
    ● Ahead-of-time compiled WebAssembly
    bytecode manually deployed on-chain
    on NEAR, and authenticated with the
    Aurora Engine registry by the deployer
    ● Untrusted, arbitrary bytecode deployed
    directly by third parties
    ● Some challenges and trade-os for
    interacting with other EVM contracts
    (cross-shard calls)
    ● Doesn’t require anything in particular
    from NEAR and nearcore
    EVM to WebAssembly: Execution models
    

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27. aurora.dev
    2022-09-13
    See you at NEAR Space in Bogota
    during Devcon, October 13, 2022!
    Thank you!
    

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