/// <summary>
/// Determines whether a variable should be inlined in non-aggressive mode, even though it is not a generated variable.
/// </summary>
/// <param name="next">The next top-level expression</param>
/// <param name="loadInst">The load within 'next'</param>
/// <param name="inlinedExpression">The expression being inlined</param>
static bool NonAggressiveInlineInto(ILInstruction next, ILInstruction loadInst, ILInstruction inlinedExpression, ILVariable v)
{
Debug.Assert(loadInst.IsDescendantOf(next));
// decide based on the source expression being inlined
switch (inlinedExpression.OpCode)
{
case OpCode.DefaultValue:
case OpCode.StObj:
case OpCode.CompoundAssignmentInstruction:
case OpCode.Await:
return(true);
case OpCode.LdLoc:
if (v.StateMachineField == null && ((LdLoc)inlinedExpression).Variable.StateMachineField != null)
{
// Roslyn likes to put the result of fetching a state machine field into a temporary variable,
// so inline more aggressively in such cases.
return(true);
}
break;
}
var parent = loadInst.Parent;
if (parent is ILiftableInstruction liftable && liftable.IsLifted)
{
return(true); // inline into lifted operators
}
if (parent is NullCoalescingInstruction && NullableType.IsNullable(v.Type))
{
return(true); // inline nullables into ?? operator
}
// decide based on the target into which we are inlining
switch (next.OpCode)
{
case OpCode.Leave:
return(parent == next);
case OpCode.IfInstruction:
while (parent.MatchLogicNot(out _))
{
parent = parent.Parent;
}
return(parent == next);
case OpCode.SwitchInstruction:
return(parent == next || (parent.MatchBinaryNumericInstruction(BinaryNumericOperator.Sub) && parent.Parent == next));
default:
return(false);
}
}
/// <summary>
/// Gets whether 'expressionBeingMoved' can be moved from somewhere before 'stmt' to become the replacement of 'targetLoad'.
/// </summary>
public static bool CanMoveInto(ILInstruction expressionBeingMoved, ILInstruction stmt, ILInstruction targetLoad)
{
Debug.Assert(targetLoad.IsDescendantOf(stmt));
for (ILInstruction inst = targetLoad; inst != stmt; inst = inst.Parent)
{
if (!inst.Parent.CanInlineIntoSlot(inst.ChildIndex, expressionBeingMoved))
{
return(false);
}
// Check whether re-ordering with predecessors is valid:
int childIndex = inst.ChildIndex;
for (int i = 0; i < childIndex; ++i)
{
ILInstruction predecessor = inst.Parent.Children[i];
if (!IsSafeForInlineOver(predecessor, expressionBeingMoved))
{
return(false);
}
}
}
return(true);
}
/// <summary>
/// Gets whether arg can be un-inlined out of stmt.
/// </summary>
internal static bool CanUninline(ILInstruction arg, ILInstruction stmt)
{
Debug.Assert(arg.IsDescendantOf(stmt));
for (ILInstruction inst = arg; inst != stmt; inst = inst.Parent)
{
if (!inst.SlotInfo.CanInlineInto)
{
return(false);
}
// Check whether re-ordering with predecessors is valid:
int childIndex = inst.ChildIndex;
for (int i = 0; i < childIndex; ++i)
{
ILInstruction predecessor = inst.Parent.Children[i];
if (!SemanticHelper.MayReorder(arg, predecessor))
{
return(false);
}
}
}
return(true);
}
/// <summary>
/// Determines whether a variable should be inlined in non-aggressive mode, even though it is not a generated variable.
/// </summary>
/// <param name="next">The next top-level expression</param>
/// <param name="loadInst">The load within 'next'</param>
/// <param name="inlinedExpression">The expression being inlined</param>
static bool NonAggressiveInlineInto(ILInstruction next, ILInstruction loadInst, ILInstruction inlinedExpression, ILVariable v)
{
Debug.Assert(loadInst.IsDescendantOf(next));
// decide based on the source expression being inlined
switch (inlinedExpression.OpCode)
{
case OpCode.DefaultValue:
case OpCode.StObj:
case OpCode.NumericCompoundAssign:
case OpCode.UserDefinedCompoundAssign:
case OpCode.Await:
return(true);
case OpCode.LdLoc:
if (v.StateMachineField == null && ((LdLoc)inlinedExpression).Variable.StateMachineField != null)
{
// Roslyn likes to put the result of fetching a state machine field into a temporary variable,
// so inline more aggressively in such cases.
return(true);
}
break;
}
var parent = loadInst.Parent;
if (NullableLiftingTransform.MatchNullableCtor(parent, out _, out _))
{
// inline into nullable ctor call in lifted operator
parent = parent.Parent;
}
if (parent is ILiftableInstruction liftable && liftable.IsLifted)
{
return(true); // inline into lifted operators
}
switch (parent.OpCode)
{
case OpCode.NullCoalescingInstruction:
if (NullableType.IsNullable(v.Type))
{
return(true); // inline nullables into ?? operator
}
break;
case OpCode.NullableUnwrap:
return(true); // inline into ?. operator
case OpCode.UserDefinedLogicOperator:
case OpCode.DynamicLogicOperatorInstruction:
return(true); // inline into (left slot of) user-defined && or || operator
case OpCode.DynamicGetMemberInstruction:
case OpCode.DynamicGetIndexInstruction:
case OpCode.LdObj:
if (parent.Parent.OpCode == OpCode.DynamicCompoundAssign)
{
return(true); // inline into dynamic compound assignments
}
break;
}
// decide based on the target into which we are inlining
switch (next.OpCode)
{
case OpCode.Leave:
case OpCode.YieldReturn:
return(parent == next);
case OpCode.IfInstruction:
while (parent.MatchLogicNot(out _))
{
parent = parent.Parent;
}
return(parent == next);
case OpCode.BlockContainer:
if (((BlockContainer)next).EntryPoint.Instructions[0] is SwitchInstruction switchInst)
{
next = switchInst;
goto case OpCode.SwitchInstruction;
}
else
{
return(false);
}
case OpCode.SwitchInstruction:
return(parent == next || (parent.MatchBinaryNumericInstruction(BinaryNumericOperator.Sub) && parent.Parent == next));
default:
return(false);
}
}