internal static ValueObject GetInitExpr(InitExpr init, List <GlobalInstance> initialized_globals)
{
if (init.expr.Length < 3)
{
throw new Exception("Unexpected init expression.");
}
uint pc = 0;
ValueObject ret = null;
switch (init.expr[0])
{
case (byte)WebAssemblyOpcode.I32_CONST:
ret = new ValueObject(LEB128.ReadUInt32(init.expr, ref pc));
break;
case (byte)WebAssemblyOpcode.I64_CONST:
ret = new ValueObject(LEB128.ReadUInt64(init.expr, ref pc));
break;
case (byte)WebAssemblyOpcode.F32_CONST:
ret = new ValueObject(BitConverter.ToSingle(init.expr, (int)pc));
break;
case (byte)WebAssemblyOpcode.F64_CONST:
ret = new ValueObject(BitConverter.ToDouble(init.expr, (int)pc));
break;
case (byte)WebAssemblyOpcode.GLOBAL_GET:
GlobalInstance gi = initialized_globals[LEB128.ReadInt32(init.expr, ref pc)];
if (!gi.is_mutable)
{
throw new Exception("Unexpected init expression.");
}
ret = gi.value;
break;
default:
throw new Exception("Invalid init expression. Expected only simple constant load instruction or global get.");
}
pc++;
if (init.expr[pc] != (byte)WebAssemblyOpcode.END || init.expr.Length > pc)
{
throw new Exception("Invalid init expression.");
}
return(ret);
}
private (byte[] memory, int location) LoadOrFail(byte[] code, uint size, ref uint pc)
{
// align is in bytes
// it tells us how this value is aligned
// in our implementation, we can disregard alignment
int align = 1 << (int)LEB128.ReadUInt32(code, ref pc);
uint offset = LEB128.ReadUInt32(code, ref pc);
ValueObject i = GetValueOfTypeOrFail(WebAssemblyType.i32);
long ea = i.AsI32() + offset;
uint N = size / 8;
if ((ea + N) > ctx.linear_memory[0].size)
{
Trap("Illegal memory access");
}
logger.ConditionalTrace($"Memory location calculated = {ea}.");
return(ctx.linear_memory[0].memory, (int)ea);
}
// TODO: Can now transform Execute from a recursive function into an iterative function
// Each time a new "frame" is added, we just update activation_object and func
// ctx records the current pc so when we go back
// Simply need to inline the Invoke method into Execute
private void Execute()
{
try
{
ActivationObject activation_object = ctx.GetCurrentFunction();
FunctionInstance func = activation_object.function;
byte[] code = func.code;
logger.Info($"Entering Execute with function {func.module}.{func.name}.");
logger.ConditionalTrace($"Function returns: {func.return_type}.");
logger.ConditionalTrace("Function parameters: {0}.", WebAssemblyHelper.ToString(func.parameters, ", "));
logger.ConditionalTrace("Function arguments: {0}.", WebAssemblyHelper.ToString(activation_object.parameters, ", "));
logger.ConditionalTrace("Function locals: {0}.", WebAssemblyHelper.ToString(func.locals, ", "));
//WebAssemblyHelper.ReinterpretHelper reinterpret_helper = new WebAssemblyHelper.ReinterpretHelper();
bool continue_executing = true;
// https://webassembly.github.io/spec/core/exec/instructions.html
while (continue_executing)
{
logger.ConditionalTrace($"PC = {activation_object.pc}.");
logger.Debug($"Executing: {(WebAssemblyOpcode)code[activation_object.pc]}.");
switch ((WebAssemblyOpcode)code[activation_object.pc])
{
case WebAssemblyOpcode.UNREACHABLE:
{
Trap("Unreachable reached!");
break;
}
case WebAssemblyOpcode.NOP:
{
break;
}
case WebAssemblyOpcode.END:
{
continue_executing = false;
break;
}
case WebAssemblyOpcode.LOOP:
{
// ignore result for now
activation_object.pc++;
var result = (WebAssemblyType)code[activation_object.pc];
Enter(new LabelObject(0, activation_object.pc - 2));
break;
}
case WebAssemblyOpcode.BR:
{
uint l = LEB128.ReadUInt32(code, ref activation_object.pc);
Exit(l);
break;
}
case WebAssemblyOpcode.BR_IF:
{
ValueObject c = GetValueOfTypeOrFail(WebAssemblyType.i32);
if (c.AsI32() != 0)
{
goto case WebAssemblyOpcode.BR;
}
break;
}
case WebAssemblyOpcode.LOCAL_GET:
{
uint local = LEB128.ReadUInt32(code, ref activation_object.pc);
if (local > func.locals.Length)
{
Trap("Function corrupt.");
}
ctx.Push(activation_object.locals[local]);
break;
}
case WebAssemblyOpcode.LOCAL_SET:
{
uint local = LEB128.ReadUInt32(code, ref activation_object.pc);
if (local > func.locals.Length)
{
Trap("Function corrupt.");
}
ValueObject val = GetValueOrFail();
activation_object.locals[local] = val;
break;
}
case WebAssemblyOpcode.LOCAL_TEE:
{
ValueObject val = GetValueOrFail();
ctx.Push(val);
ctx.Push(val);
goto case WebAssemblyOpcode.LOCAL_SET;
}
case WebAssemblyOpcode.I32_CONST:
{
ctx.Push(new ValueObject(LEB128.ReadUInt32(code, ref activation_object.pc)));
break;
}
case WebAssemblyOpcode.I64_CONST:
{
ctx.Push(new ValueObject(LEB128.ReadUInt64(code, ref activation_object.pc)));
break;
}
case WebAssemblyOpcode.F32_CONST:
{
ctx.Push(new ValueObject(BitConverter.ToSingle(code, (int)activation_object.pc + 1)));
activation_object.pc += 4;
break;
}
case WebAssemblyOpcode.F64_CONST:
{
ctx.Push(new ValueObject(BitConverter.ToDouble(code, (int)activation_object.pc + 1)));
activation_object.pc += 7;
break;
}
case WebAssemblyOpcode.I32_LOAD:
{
var(memory, location) = LoadOrFail(code, 32, ref activation_object.pc);
ctx.Push(new ValueObject(BitConverter.ToUInt32(memory, location)));
break;
}
case WebAssemblyOpcode.I64_LOAD:
{
var(memory, location) = LoadOrFail(code, 64, ref activation_object.pc);
ctx.Push(new ValueObject(BitConverter.ToUInt64(memory, location)));
break;
}
case WebAssemblyOpcode.F32_LOAD:
{
var(memory, location) = LoadOrFail(code, 32, ref activation_object.pc);
ctx.Push(new ValueObject(BitConverter.ToSingle(memory, location)));
break;
}
case WebAssemblyOpcode.F64_LOAD:
{
var(memory, location) = LoadOrFail(code, 64, ref activation_object.pc);
ctx.Push(new ValueObject(BitConverter.ToDouble(memory, location)));
break;
}
case WebAssemblyOpcode.I32_LOAD8_S:
{
var(memory, location) = LoadOrFail(code, 8, ref activation_object.pc);
ctx.Push(new ValueObject((uint)(sbyte)memory[location]));
break;
}
case WebAssemblyOpcode.I32_LOAD8_U:
{
var(memory, location) = LoadOrFail(code, 8, ref activation_object.pc);
ctx.Push(new ValueObject((uint)memory[location]));
break;
}
case WebAssemblyOpcode.I32_LOAD16_S:
{
var(memory, location) = LoadOrFail(code, 16, ref activation_object.pc);
ctx.Push(new ValueObject((uint)BitConverter.ToInt16(memory, (int)activation_object.pc)));
break;
}
case WebAssemblyOpcode.I32_LOAD16_U:
{
var(memory, location) = LoadOrFail(code, 16, ref activation_object.pc);
ctx.Push(new ValueObject(BitConverter.ToUInt16(memory, (int)activation_object.pc)));
break;
}
case WebAssemblyOpcode.I64_LOAD8_S:
{
var(memory, location) = LoadOrFail(code, 8, ref activation_object.pc);
ctx.Push(new ValueObject((ulong)(sbyte)memory[location]));
break;
}
case WebAssemblyOpcode.I64_LOAD8_U:
{
var(memory, location) = LoadOrFail(code, 8, ref activation_object.pc);
ctx.Push(new ValueObject((ulong)memory[location]));
break;
}
case WebAssemblyOpcode.I64_LOAD16_S:
{
var(memory, location) = LoadOrFail(code, 16, ref activation_object.pc);
ctx.Push(new ValueObject((ulong)BitConverter.ToInt16(memory, (int)activation_object.pc)));
break;
}
case WebAssemblyOpcode.I64_LOAD16_U:
{
var(memory, location) = LoadOrFail(code, 16, ref activation_object.pc);
ctx.Push(new ValueObject((ulong)BitConverter.ToUInt16(memory, (int)activation_object.pc)));
break;
}
case WebAssemblyOpcode.I64_LOAD32_S:
{
var(memory, location) = LoadOrFail(code, 32, ref activation_object.pc);
ctx.Push(new ValueObject((ulong)BitConverter.ToInt32(memory, (int)activation_object.pc)));
break;
}
case WebAssemblyOpcode.I64_LOAD32_U:
{
var(memory, location) = LoadOrFail(code, 32, ref activation_object.pc);
ctx.Push(new ValueObject((ulong)BitConverter.ToUInt32(memory, (int)activation_object.pc)));
break;
}
case WebAssemblyOpcode.I32_STORE:
{
var(value, memory, location) = StoreOrFail(code, 32, WebAssemblyType.i32, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes(value.AsI32()), 0, memory, location, 32 / 8);
break;
}
case WebAssemblyOpcode.I64_STORE:
{
var(value, memory, location) = StoreOrFail(code, 64, WebAssemblyType.i64, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes(value.AsI64()), 0, memory, location, 64 / 8);
break;
}
case WebAssemblyOpcode.F32_STORE:
{
var(value, memory, location) = StoreOrFail(code, 32, WebAssemblyType.f32, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes(value.AsF32()), 0, memory, location, 32 / 8);
break;
}
case WebAssemblyOpcode.F64_STORE:
{
var(value, memory, location) = StoreOrFail(code, 64, WebAssemblyType.f64, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes(value.AsF64()), 0, memory, location, 64 / 8);
break;
}
case WebAssemblyOpcode.I32_STORE8:
{
var(value, memory, location) = StoreOrFail(code, 32, WebAssemblyType.i32, ref activation_object.pc);
memory[location] = (byte)value.AsI32();
break;
}
case WebAssemblyOpcode.I32_STORE16:
{
var(value, memory, location) = StoreOrFail(code, 32, WebAssemblyType.i32, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes((ushort)value.AsI32()), 0, memory, location, 16 / 8);
break;
}
case WebAssemblyOpcode.I64_STORE8:
{
var(value, memory, location) = StoreOrFail(code, 64, WebAssemblyType.i64, ref activation_object.pc);
memory[location] = (byte)value.AsI64();
break;
}
case WebAssemblyOpcode.I64_STORE16:
{
var(value, memory, location) = StoreOrFail(code, 64, WebAssemblyType.i64, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes((ushort)value.AsI64()), 0, memory, location, 16 / 8);
break;
}
case WebAssemblyOpcode.I64_STORE32:
{
var(value, memory, location) = StoreOrFail(code, 64, WebAssemblyType.i64, ref activation_object.pc);
Array.Copy(BitConverter.GetBytes((uint)value.AsI64()), 0, memory, location, 32 / 8);
break;
}
case WebAssemblyOpcode.MEMORY_SIZE:
{
ctx.Push(new ValueObject((uint)ctx.linear_memory[0].pages));
break;
}
case WebAssemblyOpcode.MEMORY_GROW:
{
ValueObject n = GetValueOfTypeOrFail(WebAssemblyType.i32);
if (ctx.linear_memory[0].GrowMemory(n.AsI32()))
{
ctx.Push(n);
}
else
{
ctx.Push(new ValueObject(unchecked ((uint)-1)));
}
break;
}
case WebAssemblyOpcode.CALL:
{
uint new_func = LEB128.ReadUInt32(code, ref activation_object.pc);
ctx.Push(Invoke(new_func));
break;
}
case WebAssemblyOpcode.DROP:
{
GetValueOrFail();
break;
}
case WebAssemblyOpcode.SELECT:
{
ValueObject c = GetValueOfTypeOrFail(WebAssemblyType.i32);
ValueObject val2 = GetValueOrFail();
ValueObject val1 = GetValueOrFail();
ctx.Push(c.AsI32() != 0 ? val1 : val2);
break;
}
default:
{
Trap($"Unknown Opcode {code[activation_object.pc]}.");
break;
}
}
activation_object.pc++;
}
}
catch (WebAssemblyTrap)
{
throw;
}
catch (Exception ex)
{
logger.Debug(ex.StackTrace);
Trap("Unexpected Error: " + ex.Message);
}
}
