fuel-vm 0.66.3

FuelVM interpreter.
Documentation 
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use alloc::{
    vec,
    vec::Vec,
};

use crate::{
    prelude::*,
    script_with_data_offset,
};
use fuel_asm::{
    RegId,
    op,
};
use fuel_types::canonical::Serialize;
use rand::{
    Rng,
    SeedableRng,
    rngs::StdRng,
};

#[test]
fn cgas_overflow_bug() {
    let rng = &mut StdRng::seed_from_u64(2322u64);

    let gas_limit = 1_000_000;
    let asset_id: AssetId = rng.r#gen();
    let call_amount = 500;
    let initial_internal_balance = 1_000_000;

    let mut test_context = TestBuilder::new(2322u64);
    let dest_contract_id = test_context
        .setup_contract(
            vec![
                // log the balance register
                op::ret(RegId::BAL),
            ],
            None,
            None,
        )
        .contract_id;

    let program = vec![
        // load amount of tokens
        op::addi(0x10, RegId::FP, CallFrame::a_offset() as Immediate12),
        op::lw(0x10, 0x10, 0),
        // load asset id
        op::addi(0x11, RegId::FP, CallFrame::b_offset() as Immediate12),
        op::lw(0x11, 0x11, 0),
        // load contract id
        op::addi(0x12, 0x11, 32 as Immediate12),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::call(0x12, 0x10, 0x11, RegId::CGAS),
        op::log(RegId::CGAS, RegId::GGAS, RegId::ZERO, RegId::ZERO),
        op::ret(RegId::BAL),
    ];
    let sender_contract_id = test_context
        .setup_contract(program, Some((asset_id, initial_internal_balance)), None)
        .contract_id;

    let (script_ops, offset) = script_with_data_offset!(
        data_offset,
        vec![
            // load call data to 0x10
            op::movi(0x10, data_offset + 64),
            // call the transfer contract
            op::call(0x10, RegId::ZERO, RegId::ZERO, RegId::CGAS),
            op::ret(RegId::ONE),
        ],
        test_context.get_tx_params().tx_offset()
    );
    let script_data: Vec<u8> = [
        asset_id.as_ref(),
        dest_contract_id.as_ref(),
        Call::new(sender_contract_id, call_amount, offset as Word)
            .to_bytes()
            .as_slice(),
    ]
    .into_iter()
    .flatten()
    .copied()
    .collect();

    // initiate the call between contracts
    let transfer_tx = test_context
        .start_script(script_ops, script_data)
        .script_gas_limit(gas_limit)
        .gas_price(0)
        .contract_input(sender_contract_id)
        .contract_input(dest_contract_id)
        .fee_input()
        .contract_output(&sender_contract_id)
        .contract_output(&dest_contract_id)
        .execute();

    // Ensure transfer tx processed correctly
    assert!(!transfer_tx.should_revert());

    for receipt in transfer_tx.receipts() {
        if let Receipt::Log {
            ra: cgas, rb: ggas, ..
        } = receipt
        {
            assert!(cgas <= ggas, "CGAS exceeded GGAS");
        }
    }
}

#[test]
fn cgas_uses_min_available_gas() {
    let rng = &mut StdRng::seed_from_u64(2322u64);

    let gas_limit = 1_000_000;
    let asset_id: AssetId = rng.r#gen();
    let call_amount = 0;
    let initial_internal_balance = 1_000_000;
    let gas_forward_amount = 20_000;
    let call_depth = 3;

    // assign registers
    let reg_call_a = 0x10;
    let reg_call_b = 0x11;
    let reg_contract_id = 0x12;
    let reg_max_call_depth = 0x13;
    let reg_max_call_depth_eq = 0x14;
    let reg_forward_gas = 0x15;

    let mut test_context = TestBuilder::new(2322u64);
    let dest_contract_id = test_context
        .setup_contract(
            vec![
                // jump to return if we hit end of call depth
                op::eq(reg_max_call_depth_eq, reg_max_call_depth, RegId::ZERO),
                op::jnzi(reg_max_call_depth_eq, 6),
                // log cgas before call
                op::log(RegId::CGAS, RegId::GGAS, reg_max_call_depth, RegId::ZERO),
                // decrement depth
                op::subi(reg_max_call_depth, reg_max_call_depth, 1),
                // make call to contract again
                op::call(reg_contract_id, reg_call_a, reg_call_b, reg_forward_gas),
                // log cgas after call
                op::log(RegId::CGAS, RegId::GGAS, reg_max_call_depth, RegId::ZERO),
                op::ret(RegId::ZERO),
            ],
            None,
            None,
        )
        .contract_id;

    let program = vec![
        // load amount of tokens
        op::addi(reg_call_a, RegId::FP, CallFrame::a_offset() as Immediate12),
        op::lw(reg_call_a, reg_call_a, 0),
        // load asset id
        op::addi(reg_call_b, RegId::FP, CallFrame::b_offset() as Immediate12),
        op::lw(reg_call_b, reg_call_b, 0),
        // load contract id
        op::addi(reg_contract_id, reg_call_b, 32 as Immediate12),
        // set call depth
        op::movi(reg_max_call_depth, call_depth),
        // set inner call cgas limit
        op::movi(reg_forward_gas, gas_forward_amount),
        op::call(reg_contract_id, reg_call_a, reg_call_b, RegId::CGAS),
        op::log(RegId::CGAS, RegId::GGAS, RegId::ZERO, RegId::ZERO),
        op::ret(RegId::BAL),
    ];
    let sender_contract_id = test_context
        .setup_contract(program, Some((asset_id, initial_internal_balance)), None)
        .contract_id;

    let (script_ops, offset) = script_with_data_offset!(
        data_offset,
        vec![
            // load call data to 0x10
            op::movi(0x10, data_offset + 64),
            // call the transfer contract
            op::call(0x10, RegId::ZERO, RegId::ZERO, RegId::CGAS),
            op::ret(RegId::ONE),
        ],
        test_context.get_tx_params().tx_offset()
    );
    let script_data: Vec<u8> = [
        asset_id.as_ref(),
        dest_contract_id.as_ref(),
        Call::new(sender_contract_id, call_amount, offset as Word)
            .to_bytes()
            .as_slice(),
    ]
    .into_iter()
    .flatten()
    .copied()
    .collect();

    // initiate the call between contracts
    let transfer_tx = test_context
        .start_script(script_ops, script_data)
        .script_gas_limit(gas_limit)
        .gas_price(0)
        .contract_input(sender_contract_id)
        .contract_input(dest_contract_id)
        .fee_input()
        .contract_output(&sender_contract_id)
        .contract_output(&dest_contract_id)
        .execute();

    // Ensure transfer tx processed correctly
    assert!(!transfer_tx.should_revert());

    // Ensure cgas is allowed to go below gas forward amount without panicking
    assert!(transfer_tx
        .receipts()
        .iter()
        .any(|receipt| matches!(&receipt, Receipt::Log {ra: cgas, ..} if *cgas < gas_forward_amount.into())));
}