ExecutionFrame.zig

/// Frame represents the entire execution state of the EVM as it executes opcodes
/// Layout designed around actual opcode access patterns and data correlations
pub const Frame = struct {
    // ULTRA HOT - Accessed by virtually every opcode
    stack: Stack, // 33,536 bytes - accessed by every opcode (PUSH/POP/DUP/SWAP/arithmetic/etc)
    gas_remaining: u64, // 8 bytes - checked/consumed by every opcode for gas accounting
    // HOT - Accessed by major opcode categories
    memory: *Memory, // 8 bytes - hot for memory ops (MLOAD/MSTORE/MSIZE/MCOPY/LOG*/KECCAK256)
    analysis: *const CodeAnalysis, // 8 bytes - hot for control flow (JUMP/JUMPI validation)
    // Hot execution flags (only the bits that are actually checked frequently)
    // Packed together to minimize cache footprint - these are checked by different opcode categories
    hot_flags: packed struct {
        depth: u10, // 10 bits - call stack depth for CALL/CREATE operations
        is_static: bool, // 1 bit - static call restriction (checked by SSTORE/TSTORE)
        is_eip1153: bool, // 1 bit - transient storage validation (TLOAD/TSTORE)
        _padding: u4 = 0, // 4 bits - align to byte boundary and room for future flags
    },
    // High correlation group
    // All storage operations (SLOAD/SSTORE/TLOAD/TSTORE) need ALL of these together so pack them together in struct
    contract_address: primitives.Address.Address, // 20 bytes - FIRST: storage key = hash(contract_address, slot)
    state: DatabaseInterface, // 16 bytes - actual storage read/write interface
    access_list: *AccessList, // 8 bytes - LAST: EIP-2929 warm/cold gas cost calculation
    // Total: 44 bytes - all storage operations cause exactly one cache line fetch for this cluster
    // TIER 4: COLD - Rarely accessed data
    allocator: std.mem.Allocator, // 16
    input: []const u8, // 16 bytes - only 3 opcodes: CALLDATALOAD/SIZE/COPY (rare in most contracts)
    output: []const u8, // 16 bytes - only set by RETURN/REVERT at function exit
    // Cold hardfork detection flags - only used by getHardfork() method for version detection
    // Packed separately from hot flags to avoid polluting hot cache lines
    cold_flags: packed struct {
        is_prague: bool, // 1 bit
        is_cancun: bool, // 1 bit
        is_shanghai: bool, // 1 bit
        is_merge: bool, // 1 bit
        is_london: bool, // 1 bit
        is_berlin: bool, // 1 bit
        is_istanbul: bool, // 1 bit
        is_petersburg: bool, // 1 bit
        is_constantinople: bool, // 1 bit
        is_byzantium: bool, // 1 bit
        is_homestead: bool, // 1 bit
        _reserved: u5 = 0, // 5 bits - future expansion
    },
    self_destruct: ?*SelfDestruct, // 8 bytes - extremely rare: only SELFDESTRUCT opcode