private bool TryGetConstantArgument(MethodIL methodIL, byte[] body, OpcodeFlags[] flags, int offset, int argIndex, out int constant)
{
if ((flags[offset] & OpcodeFlags.BasicBlockStart) != 0)
{
constant = 0;
return(false);
}
for (int currentOffset = offset - 1; currentOffset >= 0; currentOffset--)
{
if ((flags[currentOffset] & OpcodeFlags.InstructionStart) == 0)
{
continue;
}
ILReader reader = new ILReader(body, currentOffset);
ILOpcode opcode = reader.ReadILOpcode();
if (opcode == ILOpcode.call || opcode == ILOpcode.callvirt)
{
MethodDesc method = (MethodDesc)methodIL.GetObject(reader.ReadILToken());
if (argIndex == 0)
{
BodySubstitution substitution = GetSubstitution(method);
if (substitution != null && substitution.Value is int &&
(opcode != ILOpcode.callvirt || !method.IsVirtual))
{
constant = (int)substitution.Value;
return(true);
}
else
{
constant = 0;
return(false);
}
}
argIndex--;
if (method.Signature.Length > 0 || !method.Signature.IsStatic)
{
// We don't know how to skip over the parameters
break;
}
}
else if (opcode == ILOpcode.ldsfld)
{
FieldDesc field = (FieldDesc)methodIL.GetObject(reader.ReadILToken());
if (argIndex == 0)
{
object substitution = GetSubstitution(field);
if (substitution is int)
{
constant = (int)substitution;
return(true);
}
else
{
constant = 0;
return(false);
}
}
argIndex--;
}
else if (opcode >= ILOpcode.ldc_i4_0 && opcode <= ILOpcode.ldc_i4_8)
{
if (argIndex == 0)
{
constant = opcode - ILOpcode.ldc_i4_0;
return(true);
}
argIndex--;
}
else if (opcode == ILOpcode.ldc_i4)
{
if (argIndex == 0)
{
constant = (int)reader.ReadILUInt32();
return(true);
}
argIndex--;
}
else if (opcode == ILOpcode.ldc_i4_s)
{
if (argIndex == 0)
{
constant = (int)(sbyte)reader.ReadILByte();
return(true);
}
argIndex--;
}
else if ((opcode == ILOpcode.ldloc || opcode == ILOpcode.ldloc_s ||
(opcode >= ILOpcode.ldloc_0 && opcode <= ILOpcode.ldloc_3)) &&
((flags[currentOffset] & OpcodeFlags.BasicBlockStart) == 0))
{
// Paired stloc/ldloc that the C# compiler generates in debug code?
int locIndex = opcode switch
{
ILOpcode.ldloc => reader.ReadILUInt16(),
ILOpcode.ldloc_s => reader.ReadILByte(),
_ => opcode - ILOpcode.ldloc_0,
};
for (int potentialStlocOffset = currentOffset - 1; potentialStlocOffset >= 0; potentialStlocOffset--)
{
if ((flags[potentialStlocOffset] & OpcodeFlags.InstructionStart) == 0)
{
continue;
}
ILReader nestedReader = new ILReader(body, potentialStlocOffset);
ILOpcode otherOpcode = nestedReader.ReadILOpcode();
if ((otherOpcode == ILOpcode.stloc || otherOpcode == ILOpcode.stloc_s ||
(otherOpcode >= ILOpcode.stloc_0 && otherOpcode <= ILOpcode.stloc_3)) &&
otherOpcode switch
{
ILOpcode.stloc => nestedReader.ReadILUInt16(),
ILOpcode.stloc_s => nestedReader.ReadILByte(),
_ => otherOpcode - ILOpcode.stloc_0,
} == locIndex)
public void Scan(MethodIL methodBody)
{
MethodDesc thisMethod = methodBody.OwningMethod;
ValueBasicBlockPair[] locals = new ValueBasicBlockPair[methodBody.GetLocals().Length];
Dictionary <int, Stack <StackSlot> > knownStacks = new Dictionary <int, Stack <StackSlot> >();
Stack <StackSlot> currentStack = new Stack <StackSlot>(methodBody.MaxStack);
ScanExceptionInformation(knownStacks, methodBody);
BasicBlockIterator blockIterator = new BasicBlockIterator(methodBody);
MethodReturnValue = null;
ILReader reader = new ILReader(methodBody.GetILBytes());
while (reader.HasNext)
{
int curBasicBlock = blockIterator.MoveNext(reader.Offset);
if (knownStacks.ContainsKey(reader.Offset))
{
if (currentStack == null)
{
// The stack copy constructor reverses the stack
currentStack = new Stack <StackSlot>(knownStacks[reader.Offset].Reverse());
}
else
{
currentStack = MergeStack(currentStack, knownStacks[reader.Offset]);
}
}
if (currentStack == null)
{
currentStack = new Stack <StackSlot>(methodBody.MaxStack);
}
int offset = reader.Offset;
ILOpcode opcode = reader.ReadILOpcode();
switch (opcode)
{
case ILOpcode.add:
case ILOpcode.add_ovf:
case ILOpcode.add_ovf_un:
case ILOpcode.and:
case ILOpcode.div:
case ILOpcode.div_un:
case ILOpcode.mul:
case ILOpcode.mul_ovf:
case ILOpcode.mul_ovf_un:
case ILOpcode.or:
case ILOpcode.rem:
case ILOpcode.rem_un:
case ILOpcode.sub:
case ILOpcode.sub_ovf:
case ILOpcode.sub_ovf_un:
case ILOpcode.xor:
case ILOpcode.cgt:
case ILOpcode.cgt_un:
case ILOpcode.clt:
case ILOpcode.clt_un:
case ILOpcode.shl:
case ILOpcode.shr:
case ILOpcode.shr_un:
case ILOpcode.ceq:
PopUnknown(currentStack, 2, methodBody, offset);
PushUnknown(currentStack);
reader.Skip(opcode);
break;
case ILOpcode.dup:
currentStack.Push(currentStack.Peek());
break;
case ILOpcode.ldnull:
currentStack.Push(new StackSlot(NullValue.Instance));
break;
case ILOpcode.ldc_i4_0:
case ILOpcode.ldc_i4_1:
case ILOpcode.ldc_i4_2:
case ILOpcode.ldc_i4_3:
case ILOpcode.ldc_i4_4:
case ILOpcode.ldc_i4_5:
case ILOpcode.ldc_i4_6:
case ILOpcode.ldc_i4_7:
case ILOpcode.ldc_i4_8:
{
int value = opcode - ILOpcode.ldc_i4_0;
ConstIntValue civ = new ConstIntValue(value);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case ILOpcode.ldc_i4_m1:
{
ConstIntValue civ = new ConstIntValue(-1);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case ILOpcode.ldc_i4:
{
int value = (int)reader.ReadILUInt32();
ConstIntValue civ = new ConstIntValue(value);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case ILOpcode.ldc_i4_s:
{
int value = (sbyte)reader.ReadILByte();
ConstIntValue civ = new ConstIntValue(value);
StackSlot slot = new StackSlot(civ);
currentStack.Push(slot);
}
break;
case ILOpcode.arglist:
case ILOpcode.ldftn:
case ILOpcode.sizeof_:
case ILOpcode.ldc_i8:
case ILOpcode.ldc_r4:
case ILOpcode.ldc_r8:
PushUnknown(currentStack);
reader.Skip(opcode);
break;
case ILOpcode.ldarg:
case ILOpcode.ldarg_0:
case ILOpcode.ldarg_1:
case ILOpcode.ldarg_2:
case ILOpcode.ldarg_3:
case ILOpcode.ldarg_s:
case ILOpcode.ldarga:
case ILOpcode.ldarga_s:
ScanLdarg(opcode, opcode switch
{
ILOpcode.ldarg => reader.ReadILUInt16(),
ILOpcode.ldarga => reader.ReadILUInt16(),
ILOpcode.ldarg_s => reader.ReadILByte(),
ILOpcode.ldarga_s => reader.ReadILByte(),
_ => opcode - ILOpcode.ldarg_0
}, currentStack, thisMethod);
break;
