private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData _,
Predicate predicate)
{
foreach (var(_, fieldAccess) in predicate.Type as StructureType)
{
// Build a new if predicate which might become dead in the future
var trueValue = context.GetValue(
context.Block,
new FieldRef(predicate.TrueValue, fieldAccess));
var falseValue = context.GetValue(
context.Block,
new FieldRef(predicate.FalseValue, fieldAccess));
var newPredicate = context.Builder.CreatePredicate(
predicate.Location,
predicate.Condition,
trueValue,
falseValue);
// Bind the new if predicate
context.SetValue(
context.Block,
new FieldRef(predicate, fieldAccess),
newPredicate);
}
}
/// <summary>
/// Lowers structure load operations into distinct loads for each field.
/// </summary>
private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData _,
Load load)
{
var builder = context.Builder;
foreach (var(_, fieldAccess) in load.Type as StructureType)
{
// Update source address
var address = builder.CreateLoadFieldAddress(
load.Location,
load.Source,
new FieldSpan(fieldAccess));
// Load value and store its reference in the current block
var loweredLoad = builder.CreateLoad(load.Location, address);
context.SetValue(
context.Block,
new FieldRef(load, fieldAccess),
loweredLoad);
context.MarkConverted(loweredLoad);
}
context.Remove(load);
}
/// <summary>
/// Lowers phi values.
/// </summary>
private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData data,
PhiValue phi)
{
foreach (var(fieldType, fieldAccess) in phi.Type as StructureType)
{
// Build a new phi which might become dead in the future
var phiBuilder = context.Builder.CreatePhi(
phi.Location,
fieldType);
// Register the lowered phi
data.AddPhi(new LoweredPhi(
phi,
fieldAccess,
phiBuilder));
// Bind the new phi value
context.SetValue(
context.Block,
new FieldRef(phi, fieldAccess),
phiBuilder.PhiValue);
}
context.Remove(phi);
}
/// <summary>
/// Lowers get field operations into separate SSA values.
/// </summary>
private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData _,
GetField getField)
{
if (getField.Type is StructureType structureType)
{
foreach (var(_, fieldAccess) in structureType)
{
// Get the source value
var value = context.GetValue(
context.Block,
new FieldRef(
getField.ObjectValue,
new FieldSpan(
getField.FieldSpan.Index + fieldAccess.Index)));
// Bind the mapped SSA value
context.SetValue(
context.Block,
new FieldRef(getField, fieldAccess),
value);
}
context.Remove(getField);
}
else
{
var getFieldValue = context.GetValue(
context.Block,
new FieldRef(getField.ObjectValue, getField.FieldSpan));
context.ReplaceAndRemove(getField, getFieldValue);
}
}
/// <summary>
/// Converts a store node into an SSA value.
/// </summary>
private static void Convert(
SSARewriterContext <Value> context,
ConstructionData data,
Store store)
{
if (!data.TryGetConverted(store.Target, out var storeRef))
{
return;
}
Value ssaValue = store.Value;
if (!storeRef.IsDirect)
{
ssaValue = context.GetValue(context.Block, storeRef.Source);
ssaValue = context.Builder.CreateSetField(
store.Location,
ssaValue,
storeRef.FieldSpan,
store.Value);
}
context.SetValue(context.Block, storeRef.Source, ssaValue);
context.Remove(store);
}
protected static void ConvertAlloca <TConstructionData>(
SSARewriterContext <Value> context,
TConstructionData data,
Alloca alloca,
Value initValue)
where TConstructionData : IConstructionData
{
alloca.Assert(data.ContainsAlloca(alloca));
// Bind the init value and remove the allocation from the block
context.SetValue(context.Block, alloca, initValue);
data.AddConverted(alloca, new FieldRef(alloca));
context.Remove(alloca);
}
/// <summary>
/// Lowers structure values into separate SSA values.
/// </summary>
private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData _,
StructureValue structureValue)
{
foreach (var(_, fieldAccess) in structureValue.StructureType)
{
// Build the new target value
var value = structureValue[fieldAccess.Index];
// Bind the new SSA value
context.SetValue(
context.Block,
new FieldRef(structureValue, fieldAccess),
value);
}
}
/// <summary>
/// Converts an alloca node to its initial SSA value.
/// </summary>
private static void Convert(
SSARewriterContext <Value> context,
ConstructionData data,
Alloca alloca)
{
if (!data.ContainsAlloca(alloca))
{
return;
}
var initValue = context.Builder.CreateNull(
alloca.Location,
alloca.AllocaType);
context.SetValue(context.Block, alloca, initValue);
data.AddConverted(alloca, new FieldRef(alloca));
context.Remove(alloca);
}
/// <summary>
/// Lowers null values into separate SSA values.
/// </summary>
private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData _,
NullValue nullValue)
{
foreach (var(fieldType, fieldAccess) in nullValue.Type as StructureType)
{
// Build the new target value
var value = context.Builder.CreateNull(
nullValue.Location,
fieldType);
context.MarkConverted(value);
// Bind the new SSA value
context.SetValue(
context.Block,
new FieldRef(nullValue, fieldAccess),
value);
}
}
/// <summary>
/// Lowers set field operations into separate SSA values.
/// </summary>
private static void Lower(
SSARewriterContext <FieldRef> context,
LoweringData _,
SetField setField)
{
foreach (var(_, fieldAccess) in setField.Type as StructureType)
{
Value value;
if (setField.FieldSpan.Contains(fieldAccess))
{
// Get value from the source value
value = setField.Value;
if (value.Type is StructureType)
{
var getFieldAccess = fieldAccess.Subtract(
setField.FieldSpan.Index);
value = context.GetValue(
context.Block,
new FieldRef(value, getFieldAccess));
}
}
else
{
// Load the currently registered SSA value
value = context.GetValue(
context.Block,
new FieldRef(setField.ObjectValue, fieldAccess));
}
// Bind the mapped SSA value
context.SetValue(
context.Block,
new FieldRef(setField, fieldAccess),
value);
}
context.Remove(setField);
}