LibWasm WebAssembly implementation

Libraries/LibWasm/
  ├── AbstractMachine/      # Execution engine
  ├── Parser/               # Binary format parsing
  ├── Printer/              # Debug output
  ├── WASI/                 # System interface
  ├── Types.h               # WebAssembly type system
  ├── Opcode.h              # Instruction definitions
  └── Constants.h           # WebAssembly constants

class AbstractMachine {
    // Module instantiation
    // Function invocation
    // Memory management
    // Table operations
};

struct Configuration {
    Vector<Value> stack;        // Value stack
    Vector<Frame> frames;       // Call frames
    Vector<Label> labels;       // Control labels
    // Module instances
    // Memory instances
    // Table instances
};

enum class ValueType : u8 {
    I32,    // 32-bit integer
    I64,    // 64-bit integer
    F32,    // 32-bit float
    F64,    // 64-bit float
    V128,   // 128-bit vector (SIMD)
    FuncRef,    // Function reference
    ExternRef,  // External reference
};

struct FunctionType {
    Vector<ValueType> parameters;
    Vector<ValueType> results;
};

struct Limits {
    u32 min;              // Minimum size
    Optional<u32> max;    // Optional maximum size
};

// Control flow
Opcode::Unreachable    // Trap
Opcode::Nop            // No operation
Opcode::Block          // Block scope
Opcode::Loop           // Loop scope
Opcode::If             // Conditional
Opcode::Else           // Else clause
Opcode::End            // End scope
Opcode::Br             // Branch
Opcode::BrIf           // Conditional branch
Opcode::BrTable        // Branch table (switch)
Opcode::Return         // Return from function
Opcode::Call           // Call function
Opcode::CallIndirect   // Indirect call

// Integer operations (i32/i64)
Opcode::I32Add, Opcode::I64Add      // Addition
Opcode::I32Sub, Opcode::I64Sub      // Subtraction
Opcode::I32Mul, Opcode::I64Mul      // Multiplication
Opcode::I32DivS, Opcode::I64DivS    // Signed division
Opcode::I32DivU, Opcode::I64DivU    // Unsigned division

// Float operations (f32/f64)
Opcode::F32Add, Opcode::F64Add      // Addition
Opcode::F32Sub, Opcode::F64Sub      // Subtraction
Opcode::F32Mul, Opcode::F64Mul      // Multiplication
Opcode::F32Div, Opcode::F64Div      // Division

// Load operations
Opcode::I32Load        // Load 32-bit integer
Opcode::I64Load        // Load 64-bit integer
Opcode::F32Load        // Load 32-bit float
Opcode::F64Load        // Load 64-bit float
Opcode::I32Load8S      // Load signed 8-bit, extend to 32
Opcode::I32Load8U      // Load unsigned 8-bit, extend to 32

// Store operations
Opcode::I32Store       // Store 32-bit integer
Opcode::I64Store       // Store 64-bit integer
Opcode::F32Store       // Store 32-bit float
Opcode::F64Store       // Store 64-bit float

// Memory operations
Opcode::MemorySize     // Get current memory size
Opcode::MemoryGrow     // Grow memory

Opcode::LocalGet       // Read local variable
Opcode::LocalSet       // Write local variable
Opcode::LocalTee       // Write local and keep value on stack
Opcode::GlobalGet      // Read global variable
Opcode::GlobalSet      // Write global variable

class BytecodeInterpreter {
public:
    Result<void> execute(Instruction const& instruction);
    
private:
    Configuration& m_config;
    // Executes individual opcodes
    // Manages value stack
    // Handles control flow
};

struct MemoryInstance {
    Vector<u8> data;           // Memory contents
    Limits limits;             // Size constraints
    
    Result<void> grow(u32 pages);
    Result<u8> read_byte(u32 address);
    Result<void> write_byte(u32 address, u8 value);
};

struct TableInstance {
    Vector<Reference> elements;
    Limits limits;
    ReferenceType element_type;
};

namespace WASI {
    // File system operations
    Result<FileDescriptor> fd_open(...);
    Result<Size> fd_read(FileDescriptor, Buffer);
    Result<Size> fd_write(FileDescriptor, Buffer);
    Result<void> fd_close(FileDescriptor);
    
    // Environment
    Result<Vector<String>> environ_get();
    Result<Vector<String>> args_get();
    
    // Random numbers
    Result<void> random_get(Buffer);
    
    // Clock
    Result<Timestamp> clock_time_get(ClockId);
}

struct Module {
    Vector<FunctionType> types;        // Type section
    Vector<Import> imports;            // Import section
    Vector<Function> functions;        // Function section
    Vector<Table> tables;              // Table section
    Vector<Memory> memories;           // Memory section
    Vector<Global> globals;            // Global section
    Vector<Export> exports;            // Export section
    Optional<u32> start;               // Start function
    Vector<Element> elements;          // Element section
    Vector<Code> code;                 // Code section
    Vector<Data> data;                 // Data section
};

class Parser {
public:
    Result<Module> parse(ReadonlyBytes data);
    
private:
    Result<u32> parse_leb128_u32();
    Result<i32> parse_leb128_i32();
    Result<Vector<ValueType>> parse_result_type();
    Result<Instruction> parse_instruction();
};

// Convert module to WAT (WebAssembly Text Format)
String module_to_string(Module const&);

// Example output:
// (module
//   (func $add (param i32 i32) (result i32)
//     local.get 0
//     local.get 1
//     i32.add
//   )
// )

// LibWeb/WebAssembly/
class WebAssemblyModule {
    // Compile WebAssembly.Module
    // Instantiate with imports
    // Call exported functions
};

LibWasm/Tests/
  ├── spec/          # Official WebAssembly spec tests
  ├── wasi/          # WASI functionality tests
  └── custom/        # Ladybird-specific tests

namespace Wasm::Constants {
    constexpr u32 magic_number = 0x6d736100;  // "\0asm"
    constexpr u32 version = 0x01;
    constexpr u32 page_size = 65536;          // 64 KiB
    constexpr u32 max_pages = 65536;          // 4 GiB max
}