public JavaCode(JavaReader rdr, JavaMethod method, JavaAttribute.Code codeAttr)
{
rdr.Where.Push("method body");
Method = method;
MaxStack = codeAttr.maxStack;
MaxLocals = codeAttr.maxLocals;
var codeText = codeAttr.code;
Instructions = new List <Instruction>();
int offset = 0;
while (offset < codeText.Length)
{
var inst = new Instruction();
var offset0 = offset;
byte op = codeText[offset++];
byte kind;
if (op == 0xC4)
{
// wide prefix doubles operand size
op = codeText[offset++];
kind = instOperandType[op];
if ((kind & 0x10) != 0x10)
{
throw rdr.Where.Exception($"invalid use of wide opcode prefix at {(offset - 2).ToString("X4")}");
}
kind = (byte)(0x10 | ((kind & 0x0F) << 1));
if (op == 0x84)
{
inst.Data = (uint)((codeText[offset] << 24)
| (codeText[offset + 1] << 16)
| (codeText[offset + 2] << 8)
| codeText[offset + 3]);
}
else
{
inst.Data = (short)((codeText[offset] << 8) | codeText[offset + 1]);
}
}
else if (op == 0xAA || op == 0xAB)
{
offset = ReadSwitch(codeText, op, offset, inst);
if (offset == -1)
{
throw rdr.Where.Exception($"switch opcode {op:X2} not supported at offset {offset0:X4}");
}
kind = 0;
}
else
{
kind = instOperandType[op];
if ((kind & 0x80) == 0x80)
{
// constant reference
int constantIndex = codeText[offset];
if (kind >= 0x82 && kind <= 0x84)
{
constantIndex = (constantIndex << 8) | codeText[offset + 1];
}
var constantType = rdr.ConstType(constantIndex);
if (constantType == typeof(JavaConstant.String))
{
inst.Data = rdr.ConstString(constantIndex);
}
else if (constantType == typeof(JavaConstant.Integer))
{
inst.Data = rdr.ConstInteger(constantIndex);
}
else if (constantType == typeof(JavaConstant.Float))
{
inst.Data = rdr.ConstFloat(constantIndex);
}
else if (constantType == typeof(JavaConstant.Long))
{
inst.Data = rdr.ConstLong(constantIndex);
}
else if (constantType == typeof(JavaConstant.Double))
{
inst.Data = rdr.ConstDouble(constantIndex);
}
else if (constantType == typeof(JavaConstant.Class))
{
inst.Class = rdr.ConstClass(constantIndex);
}
else if (constantType == typeof(JavaConstant.FieldRef))
{
(inst.Class, inst.Data) = rdr.ConstField(constantIndex);
}
else if (constantType == typeof(JavaConstant.MethodRef))
{
(inst.Class, inst.Data) = rdr.ConstMethod(constantIndex);
}
else if (constantType == typeof(JavaConstant.InterfaceMethodRef))
{
(inst.Class, inst.Data) = rdr.ConstInterfaceMethod(constantIndex);
}
else if (constantType == typeof(JavaConstant.InvokeDynamic))
{
var callSite = rdr.ConstInvokeDynamic(constantIndex);
inst.Data = callSite;
if (rdr.callSites == null)
{
rdr.callSites = new List <JavaCallSite>();
}
rdr.callSites.Add(callSite);
}
else
{
rdr.Where.Push($"opcode {op:X2} offset {offset0:X4}");
throw rdr.Where.Exception((constantType == null)
? $"bad constant index '{constantIndex}'"
: $"unsupported constant of type '{constantType.Name}'");
}
}
else if ((kind & 0x40) == 0x40)
{
// control transfer, 32-bit or 16-bit offset
/*if ((kind & 0x4F) == 0x44)
* throw rdr.Where.Exception($"32-bit branch offsets not supported at offset {(offset - 2).ToString("X4")}");*/
int jumpOffset = ((codeText[offset] << 8) | codeText[offset + 1]);
if ((kind & 0x4F) == 0x44)
{
// 32-bit branch offset in 'goto_w' instruction
jumpOffset = (jumpOffset << 8) | codeText[offset + 2];
jumpOffset = (jumpOffset << 8) | codeText[offset + 3];
}
inst.Data = (ushort)(offset0 + jumpOffset);
}
else if ((kind & 0x30) != 0)
{
// 0x10 - one or two bytes of immediate data
// 0x20 - local variable index
if ((kind & 0x0F) == 0x01)
{
inst.Data = (int)codeText[offset];
}
else
{
inst.Data = (int)((codeText[offset] << 8) | codeText[offset + 1]);
}
}
else if (kind != 0)
{
throw rdr.Where.Exception("unknown opcode");
}
}
offset += (kind & 0x0F);
int n = offset - offset0;
inst.Bytes = new byte[offset - offset0];
for (int i = 0; i < n; i++)
{
inst.Bytes[i] = codeText[offset0 + i];
}
inst.Opcode = op;
inst.Label = (ushort)offset0;
Instructions.Add(inst);
}
ReadLineNumberTable(codeAttr);
Exceptions = new List <JavaAttribute.Code.Exception>(codeAttr.exceptions);
var stackMapAttr = codeAttr.attributes.GetAttr <JavaAttribute.StackMapTable>();
if (stackMapAttr != null)
{
StackMap = new JavaStackMap(stackMapAttr, rdr);
}
rdr.Where.Pop();
}