/// <summary>
/// Computes a linear array address.
/// </summary>
/// <param name="location">The current location.</param>
/// <param name="arrayIndex">The array index.</param>
/// <param name="arrayExtent">The array extent.</param>
/// <param name="arrayExtentOffset">The extent offset.</param>
/// <returns>The linear array address.</returns>
internal ValueReference ComputeArrayAddress(
Location location,
Value arrayIndex,
Value arrayExtent,
int arrayExtentOffset)
{
int dimensions = StructureType.GetNumFields(arrayExtent.Type);
Value linearIndex = CreateGetField(
location,
arrayIndex,
new FieldSpan(dimensions - 1));
for (int i = dimensions - 2; i >= 0; --i)
{
var extent = CreateGetField(
location,
arrayExtent,
new FieldSpan(i + arrayExtentOffset));
var index = CreateGetField(
location,
arrayIndex,
new FieldSpan(i));
linearIndex = CreateArithmetic(
location,
linearIndex,
extent,
index,
TernaryArithmeticKind.MultiplyAdd);
}
return(linearIndex);
}
/// <summary>
/// Computes a linear array length based on an array extent.
/// </summary>
/// <param name="location">The current location.</param>
/// <param name="arrayExtent">The array extent.</param>
/// <returns>The linear array length.</returns>
internal ValueReference ComputeArrayLength(
Location location,
Value arrayExtent)
{
// Compute total number of elements
var size = CreateGetField(
location,
arrayExtent,
new FieldSpan(0));
int dimensions = StructureType.GetNumFields(arrayExtent.Type);
for (int i = 1; i < dimensions; ++i)
{
var element = CreateGetField(
location,
arrayExtent,
new FieldSpan(i));
size = CreateArithmetic(
location,
size,
element,
BinaryArithmeticKind.Mul);
}
return(size);
}
/// <summary>
/// Lowers array extent values.
/// </summary>
private static void Lower(
RewriterContext context,
TypeLowering <ArrayType> typeLowering,
GetArrayExtent value)
{
var builder = context.Builder;
// Create new extent structure based on all dimension entries
int dimensions = StructureType.GetNumFields(typeLowering[value]);
var instance = builder.CreateDynamicStructure(value.Location, dimensions);
// Insert all dimension values
for (int i = 0; i < dimensions; ++i)
{
instance.Add(builder.CreateGetField(
value.Location,
value.ObjectValue,
new FieldSpan(i + ArrayTypeLowering.DimensionOffset)));
}
var newStructure = instance.Seal();
context.ReplaceAndRemove(value, newStructure);
}