private void EmitRangeCheckedBranch(ConstantValue startConstant, ConstantValue endConstant, object targetLabel)
{
_builder.EmitLoad(_key);
// Normalize the key to 0 if needed
// Emit: ldc constant
// sub
if (!startConstant.IsDefaultValue)
{
_builder.EmitConstantValue(startConstant);
_builder.EmitOpCode(ILOpCode.Sub);
}
if (_keyTypeCode.Is64BitIntegral())
{
_builder.EmitLongConstant(endConstant.Int64Value - startConstant.Int64Value);
}
else
{
_builder.EmitIntConstant(endConstant.Int32Value - startConstant.Int32Value);
}
_builder.EmitBranch(ILOpCode.Ble_un, targetLabel, ILOpCode.Bgt_un);
}
private void EmitRangeCheckIfNeeded(ConstantValue startConstant, ConstantValue endConstant, object bucketFallThroughLabel)
{
// switch treats key as an unsigned int.
// this ensures that normalization does not introduce [over|under]flows issues with 32bit or shorter keys.
// 64bit values, however must be checked before 32bit truncation happens.
if (_keyTypeCode.Is64BitIntegral())
{
// Dup(normalized);
// if ((ulong)(normalized) > (ulong)(endConstant - startConstant))
// {
// // not going to use it in the switch
// Pop(normalized);
// goto bucketFallThroughLabel;
// }
var inRangeLabel = new object();
_builder.EmitOpCode(ILOpCode.Dup);
_builder.EmitLongConstant(endConstant.Int64Value - startConstant.Int64Value);
_builder.EmitBranch(ILOpCode.Ble_un, inRangeLabel, ILOpCode.Bgt_un);
_builder.EmitOpCode(ILOpCode.Pop);
_builder.EmitBranch(ILOpCode.Br, bucketFallThroughLabel);
// If we get to inRangeLabel, we should have key on stack, adjust for that.
// builder cannot infer this since it has not seen all branches,
// but it will verify that our Adjustment is valid when more branches are known.
_builder.AdjustStack(+1);
_builder.MarkLabel(inRangeLabel);
}
}
private void EmitRangeCheckedBranch(
ConstantValue startConstant,
ConstantValue endConstant,
object targetLabel
)
{
_builder.EmitLoad(_key);
// Normalize the key to 0 if needed
// Emit: ldc constant
// sub
if (!startConstant.IsDefaultValue)
{
_builder.EmitConstantValue(startConstant);
_builder.EmitOpCode(ILOpCode.Sub);
}
if (_keyTypeCode.Is64BitIntegral())
{
_builder.EmitLongConstant(endConstant.Int64Value - startConstant.Int64Value);
}
else
{
int Int32Value(ConstantValue value)
{
// ConstantValue does not correctly convert byte and ushort values to int.
// It sign extends them rather than padding them. We compensate for that here.
// See also https://github.com/dotnet/roslyn/issues/18579
switch (value.Discriminator)
{
case ConstantValueTypeDiscriminator.Byte:
return(value.ByteValue);
case ConstantValueTypeDiscriminator.UInt16:
return(value.UInt16Value);
default:
return(value.Int32Value);
}
}
_builder.EmitIntConstant(Int32Value(endConstant) - Int32Value(startConstant));
}
_builder.EmitBranch(ILOpCode.Ble_un, targetLabel, ILOpCode.Bgt_un);
}