public ChangeAlignTo(AlignTo alignTo, AlignToHandler alignToHandler)
{
this.alignTo = alignTo;
this.alignToHandler = alignToHandler;
}
public abstract void SetAlignTo(AlignTo alignTo);
public static Icon GetIconForAlign(AlignTo align)
{
return(IconPool.GetIcon($"Tools.{Enum.GetName(typeof(AlignTo), align)}"));
}
public override void SetAlignTo(AlignTo alignTo)
{
CenterAlignTo = alignTo;
SetTextAndTexture();
}
/// <summary>
/// Lowers an align-view-to operation.
/// </summary>
private static void Lower(
RewriterContext context,
TypeLowering <ViewType> typeLowering,
AlignTo value)
{
var builder = context.Builder;
var location = value.Location;
// Extract basic view information from the converted structure
var pointer = builder.CreateGetField(
location,
value.Source,
new FieldSpan(0));
var length = builder.CreateGetField(
location,
value.Source,
new FieldSpan(1));
// Build the final result structure instance
var resultBuilder = builder.CreateDynamicStructure(location);
// Convert the current input pointer to a 64-bit integer value
var pointerAsInt = builder.CreatePointerAsIntCast(
location,
pointer,
BasicValueType.Int64);
// Compute the aligned pointer and convert it to an integer value
var aligned = builder.CreateAlignTo(
location,
pointer,
value.AlignmentInBytes);
var alignedAsInt = builder.CreatePointerAsIntCast(
location,
aligned,
BasicValueType.Int64);
// Compute the number of elements to skip:
// Min((aligned - ptr) / SizeOf(ElementType), length)
var viewType = typeLowering[value].As <ViewType>(location);
var elementsToSkip = builder.CreateArithmetic(
location,
builder.CreateArithmetic(
location,
builder.CreateArithmetic(
location,
alignedAsInt,
pointerAsInt,
BinaryArithmeticKind.Sub),
builder.CreateSizeOf(location, viewType.ElementType),
BinaryArithmeticKind.Div),
length,
BinaryArithmeticKind.Min);
// Create the prefix view that starts at the original pointer offset and
// includes elementsToSkip many elements.
{
resultBuilder.Add(pointer);
resultBuilder.Add(elementsToSkip);
}
// Create the main view that starts at the aligned pointer offset and has a
// length of remainingLength
{
resultBuilder.Add(aligned);
var remainingLength = builder.CreateArithmetic(
location,
length,
elementsToSkip,
BinaryArithmeticKind.Sub);
resultBuilder.Add(remainingLength);
}
var result = resultBuilder.Seal();
context.ReplaceAndRemove(value, result);
}
/// <summary cref="IBackendCodeGenerator.GenerateCode(AlignTo)"/>
public void GenerateCode(AlignTo value)
{
// Load the base view pointer
var source = Load(value.Source);
var target = Allocate(value);
var alignmentVariable = Load(value.AlignmentInBytes);
var arithmeticBasicValueType =
value.Source.BasicValueType.GetArithmeticBasicValueType(true);
// var baseOffset = (int)ptr & (alignmentInBytes - 1);
var baseOffset = AllocateType(arithmeticBasicValueType);
using (var statement = BeginStatement(baseOffset))
{
statement.AppendCast(arithmeticBasicValueType);
statement.AppendArgument(source);
statement.AppendCommand(CLInstructions.GetArithmeticOperation(
BinaryArithmeticKind.And,
isFloat: false,
out bool _));
// Optimize for the case in which the alignment is a constant value
if (value.TryGetAlignmentConstant(out int alignment))
{
statement.AppendConstant(alignment - 1);
}
else
{
statement.AppendCommand('(');
statement.AppendArgument(alignmentVariable);
statement.AppendCommand(CLInstructions.GetArithmeticOperation(
BinaryArithmeticKind.Sub,
isFloat: false,
out bool _));
statement.AppendConstant(1);
statement.AppendCommand(')');
}
}
// if (baseOffset == 0) { 0 } else { alignment - baseOffset }
var adjustment = AllocateType(arithmeticBasicValueType);
using (var selectStatement = BeginStatement(adjustment))
{
selectStatement.AppendArgument(baseOffset);
selectStatement.AppendCommand(" == 0 ? 0 : (");
if (value.TryGetAlignmentConstant(out int alignmentConstant))
{
selectStatement.AppendConstant(alignmentConstant);
}
else
{
selectStatement.AppendArgument(alignmentVariable);
}
selectStatement.AppendCommand(CLInstructions.GetArithmeticOperation(
BinaryArithmeticKind.Sub,
isFloat: false,
out bool _));
selectStatement.AppendArgument(baseOffset);
selectStatement.AppendCommand(')');
}
// Adjust the given pointer
using var command = BeginStatement(target);
command.AppendCast(value.Type);
command.AppendCommand('(');
command.AppendCast(arithmeticBasicValueType);
command.AppendArgument(source);
command.AppendCommand(CLInstructions.GetArithmeticOperation(
BinaryArithmeticKind.Add,
isFloat: false,
out bool _));
command.AppendArgument(adjustment);
command.AppendCommand(')');
}