protected internal override void VisitBinaryNumericInstruction(BinaryNumericInstruction inst)
{
base.VisitBinaryNumericInstruction(inst);
switch (inst.Operator)
{
case BinaryNumericOperator.ShiftLeft:
case BinaryNumericOperator.ShiftRight:
if (inst.Right.MatchBinaryNumericInstruction(BinaryNumericOperator.BitAnd, out var lhs, out var rhs) &&
rhs.MatchLdcI4(inst.ResultType == StackType.I8 ? 63 : 31))
{
// a << (b & 31) => a << b
context.Step("Combine bit.and into shift", inst);
inst.Right = lhs;
}
break;
case BinaryNumericOperator.BitAnd:
if (inst.Left.InferType(context.TypeSystem).IsKnownType(KnownTypeCode.Boolean) &&
inst.Right.InferType(context.TypeSystem).IsKnownType(KnownTypeCode.Boolean))
{
if (new NullableLiftingTransform(context).Run(inst))
{
// e.g. "(a.GetValueOrDefault() == b.GetValueOrDefault()) & (a.HasValue & b.HasValue)"
}
}
break;
}
}
protected internal override void VisitBinaryNumericInstruction(BinaryNumericInstruction inst)
{
base.VisitBinaryNumericInstruction(inst);
switch (inst.Operator)
{
case BinaryNumericOperator.ShiftLeft:
case BinaryNumericOperator.ShiftRight:
if (inst.Right.MatchBinaryNumericInstruction(BinaryNumericOperator.BitAnd, out var lhs, out var rhs) &&
rhs.MatchLdcI4(inst.ResultType == StackType.I8 ? 63 : 31))
{
// a << (b & 31) => a << b
context.Step("Combine bit.and into shift", inst);
inst.Right = lhs;
}
break;
case BinaryNumericOperator.BitAnd:
if (inst.Left.InferType(context.TypeSystem).IsKnownType(KnownTypeCode.Boolean) &&
inst.Right.InferType(context.TypeSystem).IsKnownType(KnownTypeCode.Boolean))
{
if (new NullableLiftingTransform(context).Run(inst))
{
// e.g. "(a.GetValueOrDefault() == b.GetValueOrDefault()) & (a.HasValue & b.HasValue)"
}
else if (SemanticHelper.IsPure(inst.Right.Flags))
{
context.Step("Replace bit.and with logic.and", inst);
var expr = IfInstruction.LogicAnd(inst.Left, inst.Right);
inst.ReplaceWith(expr);
expr.AcceptVisitor(this);
}
}
break;
}
}
protected internal override void VisitBinaryNumericInstruction(BinaryNumericInstruction inst)
{
base.VisitBinaryNumericInstruction(inst);
switch (inst.Operator)
{
case BinaryNumericOperator.ShiftLeft:
case BinaryNumericOperator.ShiftRight:
if (inst.Right.MatchBinaryNumericInstruction(BinaryNumericOperator.BitAnd, out var lhs, out var rhs) &&
rhs.MatchLdcI4(inst.ResultType == StackType.I8 ? 63 : 31))
{
// a << (b & 31) => a << b
context.Step("Combine bit.and into shift", inst);
inst.Right = lhs;
}
break;
case BinaryNumericOperator.BitAnd:
if (IsBoolean(inst.Left) && IsBoolean(inst.Right) && SemanticHelper.IsPure(inst.Right.Flags))
{
context.Step("Replace bit.and with logic.and", inst);
var expr = IfInstruction.LogicAnd(inst.Left, inst.Right);
inst.ReplaceWith(expr);
expr.AcceptVisitor(this);
}
break;
}
}
static bool ValidateCompoundAssign(BinaryNumericInstruction binary, Conv conv, IType targetType)
{
if (!NumericCompoundAssign.IsBinaryCompatibleWithType(binary, targetType))
{
return(false);
}
if (conv != null && !(conv.TargetType == targetType.ToPrimitiveType() && conv.CheckForOverflow == binary.CheckForOverflow))
{
return(false); // conv does not match binary operation
}
return(true);
}
/// <code>
/// stloc s(binary(callvirt(getter), value))
/// callvirt (setter, ldloc s)
/// (followed by single usage of s in next instruction)
/// -->
/// stloc s(compound.op.new(callvirt(getter), value))
/// </code>
bool TransformInlineCompoundAssignmentCall(Block block, int i)
{
var mainStLoc = block.Instructions[i] as StLoc;
// in some cases it can be a compiler-generated local
if (mainStLoc == null || (mainStLoc.Variable.Kind != VariableKind.StackSlot && mainStLoc.Variable.Kind != VariableKind.Local))
{
return(false);
}
BinaryNumericInstruction binary = mainStLoc.Value as BinaryNumericInstruction;
ILVariable localVariable = mainStLoc.Variable;
if (!localVariable.IsSingleDefinition)
{
return(false);
}
if (localVariable.LoadCount != 2)
{
return(false);
}
var getterCall = binary?.Left as CallInstruction;
var setterCall = block.Instructions.ElementAtOrDefault(i + 1) as CallInstruction;
if (!MatchingGetterAndSetterCalls(getterCall, setterCall))
{
return(false);
}
if (!setterCall.Arguments.Last().MatchLdLoc(localVariable))
{
return(false);
}
var next = block.Instructions.ElementAtOrDefault(i + 2);
if (next == null)
{
return(false);
}
if (next.Descendants.Where(d => d.MatchLdLoc(localVariable)).Count() != 1)
{
return(false);
}
if (!CompoundAssignmentInstruction.IsBinaryCompatibleWithType(binary, getterCall.Method.ReturnType))
{
return(false);
}
context.Step($"Inline compound assignment to '{getterCall.Method.AccessorOwner.Name}'", setterCall);
block.Instructions.RemoveAt(i + 1); // remove setter call
binary.ReplaceWith(new CompoundAssignmentInstruction(
binary, getterCall, binary.Right,
getterCall.Method.ReturnType, CompoundAssignmentType.EvaluatesToNewValue));
return(true);
}
/// <summary>
/// VS2017.8 / Roslyn 2.9 started optimizing some cases of
/// "a.GetValueOrDefault() == b.GetValueOrDefault() && (a.HasValue & b.HasValue)"
/// to
/// "(a.GetValueOrDefault() == b.GetValueOrDefault()) & (a.HasValue & b.HasValue)"
/// so this secondary entry point analyses logic.and as-if it was a short-circuiting &&.
/// </summary>
public bool Run(BinaryNumericInstruction bni)
{
Debug.Assert(!bni.IsLifted && bni.Operator == BinaryNumericOperator.BitAnd);
// caller ensures that bni.Left/bni.Right are booleans
var lifted = Lift(bni, bni.Left, bni.Right, new LdcI4(0));
if (lifted != null)
{
bni.ReplaceWith(lifted);
return(true);
}
return(false);
}
protected internal override void VisitBinaryNumericInstruction(BinaryNumericInstruction inst)
{
base.VisitBinaryNumericInstruction(inst);
switch (inst.Operator)
{
case BinaryNumericOperator.ShiftLeft:
case BinaryNumericOperator.ShiftRight:
if (inst.Right.MatchBinaryNumericInstruction(BinaryNumericOperator.BitAnd, out var lhs, out var rhs) &&
rhs.MatchLdcI4(inst.ResultType == StackType.I8 ? 63 : 31))
{
// a << (b & 31) => a << b
context.Step("Combine bit.and into shift", inst);
inst.Right = lhs;
}
break;
}
}
/// <summary>
/// Recursive function that lifts the specified instruction.
/// The input instruction is expected to a subexpression of the trueInst
/// (so that all nullableVars are guaranteed non-null within this expression).
///
/// Creates a new lifted instruction without modifying the input instruction.
/// On success, returns (new lifted instruction, bitset).
/// If lifting fails, returns (null, null).
///
/// The returned bitset specifies which nullableVars were considered "relevant" for this instruction.
/// bitSet[i] == true means nullableVars[i] was relevant.
///
/// The new lifted instruction will have equivalent semantics to the input instruction
/// if all relevant variables are non-null [except that the result will be wrapped in a Nullable{T} struct].
/// If any relevant variable is null, the new instruction is guaranteed to evaluate to <c>null</c>
/// without having any other effect.
/// </summary>
(ILInstruction, BitSet) DoLift(ILInstruction inst)
{
if (MatchGetValueOrDefault(inst, out ILVariable inputVar))
{
// n.GetValueOrDefault() lifted => n.
BitSet foundIndices = new BitSet(nullableVars.Count);
for (int i = 0; i < nullableVars.Count; i++)
{
if (nullableVars[i] == inputVar)
{
foundIndices[i] = true;
}
}
if (foundIndices.Any())
{
return(new LdLoc(inputVar)
{
ILRange = inst.ILRange
}, foundIndices);
}
else
{
return(null, null);
}
}
else if (inst is Conv conv)
{
var(arg, bits) = DoLift(conv.Argument);
if (arg != null)
{
if (conv.HasFlag(InstructionFlags.MayThrow) && !bits.All(0, nullableVars.Count))
{
// Cannot execute potentially-throwing instruction unless all
// the nullableVars are arguments to the instruction
// (thus causing it not to throw when any of them is null).
return(null, null);
}
var newInst = new Conv(arg, conv.InputType, conv.InputSign, conv.TargetType, conv.CheckForOverflow, isLifted: true)
{
ILRange = conv.ILRange
};
return(newInst, bits);
}
}
else if (inst is BitNot bitnot)
{
var(arg, bits) = DoLift(bitnot.Argument);
if (arg != null)
{
var newInst = new BitNot(arg, isLifted: true, stackType: bitnot.ResultType)
{
ILRange = bitnot.ILRange
};
return(newInst, bits);
}
}
else if (inst is BinaryNumericInstruction binary)
{
var(left, right, bits) = DoLiftBinary(binary.Left, binary.Right);
if (left != null && right != null)
{
if (binary.HasFlag(InstructionFlags.MayThrow) && !bits.All(0, nullableVars.Count))
{
// Cannot execute potentially-throwing instruction unless all
// the nullableVars are arguments to the instruction
// (thus causing it not to throw when any of them is null).
return(null, null);
}
var newInst = new BinaryNumericInstruction(
binary.Operator, left, right,
binary.LeftInputType, binary.RightInputType,
binary.CheckForOverflow, binary.Sign,
isLifted: true
)
{
ILRange = binary.ILRange
};
return(newInst, bits);
}
}
else if (inst is Comp comp && !comp.IsLifted && comp.Kind == ComparisonKind.Equality &&
MatchGetValueOrDefault(comp.Left, out ILVariable v) &&
NullableType.GetUnderlyingType(v.Type).IsKnownType(KnownTypeCode.Boolean) &&
comp.Right.MatchLdcI4(0)
)
{
// C# doesn't support ComparisonLiftingKind.ThreeValuedLogic,
// except for operator! on bool?.
var(arg, bits) = DoLift(comp.Left);
Debug.Assert(arg != null);
var newInst = new Comp(comp.Kind, ComparisonLiftingKind.ThreeValuedLogic, comp.InputType, comp.Sign, arg, comp.Right.Clone())
{
ILRange = comp.ILRange
};
return(newInst, bits);
}
/// <code>
/// stloc s(ldflda)
/// stloc s2(ldobj(ldflda(ldloc s)))
/// stloc l(ldloc s2)
/// stobj (ldflda(ldloc s), binary.add(ldloc s2, ldc.i4 1))
/// -->
/// stloc l(compound.op.old(ldobj(ldflda(ldflda)), ldc.i4 1))
/// </code>
bool TransformCSharp4PostIncDecOperatorOnAddress(Block block, int i)
{
var baseFieldAddress = block.Instructions[i] as StLoc;
var fieldValue = block.Instructions.ElementAtOrDefault(i + 1) as StLoc;
var fieldValueCopyToLocal = block.Instructions.ElementAtOrDefault(i + 2) as StLoc;
var stobj = block.Instructions.ElementAtOrDefault(i + 3) as StObj;
if (baseFieldAddress == null || fieldValue == null || fieldValueCopyToLocal == null || stobj == null)
{
return(false);
}
if (baseFieldAddress.Variable.Kind != VariableKind.StackSlot || fieldValue.Variable.Kind != VariableKind.StackSlot || fieldValueCopyToLocal.Variable.Kind != VariableKind.Local)
{
return(false);
}
IType t;
IField targetField;
ILInstruction targetFieldLoad, baseFieldAddressLoad2;
if (!fieldValue.Value.MatchLdObj(out targetFieldLoad, out t))
{
return(false);
}
ILInstruction baseAddress;
if (baseFieldAddress.Value is LdFlda)
{
IField targetField2;
ILInstruction baseFieldAddressLoad3;
if (!targetFieldLoad.MatchLdFlda(out baseFieldAddressLoad2, out targetField) || !baseFieldAddressLoad2.MatchLdLoc(baseFieldAddress.Variable))
{
return(false);
}
if (!stobj.Target.MatchLdFlda(out baseFieldAddressLoad3, out targetField2) || !baseFieldAddressLoad3.MatchLdLoc(baseFieldAddress.Variable) || !IsSameMember(targetField, targetField2))
{
return(false);
}
baseAddress = new LdFlda(baseFieldAddress.Value, targetField);
}
else if (baseFieldAddress.Value is LdElema)
{
if (!targetFieldLoad.MatchLdLoc(baseFieldAddress.Variable) || !stobj.Target.MatchLdLoc(baseFieldAddress.Variable))
{
return(false);
}
baseAddress = baseFieldAddress.Value;
}
else
{
return(false);
}
BinaryNumericInstruction binary = stobj.Value as BinaryNumericInstruction;
if (binary == null || !binary.Left.MatchLdLoc(fieldValue.Variable) || !binary.Right.MatchLdcI4(1) ||
(binary.Operator != BinaryNumericOperator.Add && binary.Operator != BinaryNumericOperator.Sub))
{
return(false);
}
context.Step($"TransformCSharp4PostIncDecOperatorOnAddress", baseFieldAddress);
var assignment = new CompoundAssignmentInstruction(binary, new LdObj(baseAddress, t), binary.Right, t, CompoundAssignmentType.EvaluatesToOldValue);
stobj.ReplaceWith(new StLoc(fieldValueCopyToLocal.Variable, assignment));
block.Instructions.RemoveAt(i + 2);
block.Instructions.RemoveAt(i + 1);
return(true);
}
/// <summary>
/// Recursive function that lifts the specified instruction.
/// The input instruction is expected to a subexpression of the trueInst
/// (so that all nullableVars are guaranteed non-null within this expression).
///
/// Creates a new lifted instruction without modifying the input instruction.
/// On success, returns (new lifted instruction, bitset).
/// If lifting fails, returns (null, null).
///
/// The returned bitset specifies which nullableVars were considered "relevant" for this instruction.
/// bitSet[i] == true means nullableVars[i] was relevant.
///
/// The new lifted instruction will have equivalent semantics to the input instruction
/// if all relevant variables are non-null [except that the result will be wrapped in a Nullable{T} struct].
/// If any relevant variable is null, the new instruction is guaranteed to evaluate to <c>null</c>
/// without having any other effect.
/// </summary>
(ILInstruction, BitSet) DoLift(ILInstruction inst)
{
if (MatchGetValueOrDefault(inst, out ILVariable inputVar))
{
// n.GetValueOrDefault() lifted => n.
BitSet foundIndices = new BitSet(nullableVars.Count);
for (int i = 0; i < nullableVars.Count; i++)
{
if (nullableVars[i] == inputVar)
{
foundIndices[i] = true;
}
}
if (foundIndices.Any())
{
return(new LdLoc(inputVar)
{
ILRange = inst.ILRange
}, foundIndices);
}
else
{
return(null, null);
}
}
else if (inst is Conv conv)
{
var(arg, bits) = DoLift(conv.Argument);
if (arg != null)
{
if (conv.HasFlag(InstructionFlags.MayThrow) && !bits.All(0, nullableVars.Count))
{
// Cannot execute potentially-throwing instruction unless all
// the nullableVars are arguments to the instruction
// (thus causing it not to throw when any of them is null).
return(null, null);
}
var newInst = new Conv(arg, conv.InputType, conv.InputSign, conv.TargetType, conv.CheckForOverflow, isLifted: true)
{
ILRange = conv.ILRange
};
return(newInst, bits);
}
}
else if (inst is BinaryNumericInstruction binary)
{
var(left, leftBits) = DoLift(binary.Left);
var(right, rightBits) = DoLift(binary.Right);
if (left != null && right == null && SemanticHelper.IsPure(binary.Right.Flags))
{
// Embed non-nullable pure expression in lifted expression.
right = binary.Right.Clone();
}
if (left == null && right != null && SemanticHelper.IsPure(binary.Left.Flags))
{
// Embed non-nullable pure expression in lifted expression.
left = binary.Left.Clone();
}
if (left != null && right != null)
{
var bits = leftBits ?? rightBits;
if (rightBits != null)
{
bits.UnionWith(rightBits);
}
if (binary.HasFlag(InstructionFlags.MayThrow) && !bits.All(0, nullableVars.Count))
{
// Cannot execute potentially-throwing instruction unless all
// the nullableVars are arguments to the instruction
// (thus causing it not to throw when any of them is null).
return(null, null);
}
var newInst = new BinaryNumericInstruction(
binary.Operator, left, right,
binary.LeftInputType, binary.RightInputType,
binary.CheckForOverflow, binary.Sign,
isLifted: true
)
{
ILRange = binary.ILRange
};
return(newInst, bits);
}
}
return(null, null);
}
