.NET Decompiler with support for PDB generation, ReadyToRun, Metadata (&more) - cross-platform!
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// Copyright (c) 2015 Siegfried Pammer
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System;
using System.Diagnostics;
using System.Linq;
using ICSharpCode.Decompiler.TypeSystem;
using ICSharpCode.Decompiler.TypeSystem.Implementation;
using ICSharpCode.Decompiler.Util;
namespace ICSharpCode.Decompiler.IL.Transforms
{
/// <summary>
/// Constructs compound assignments and inline assignments.
/// </summary>
public class TransformAssignment : IStatementTransform
{
StatementTransformContext context;
void IStatementTransform.Run(Block block, int pos, StatementTransformContext context)
{
this.context = context;
/*if (TransformPostIncDecOperatorOnAddress(block, i) || TransformPostIncDecOnStaticField(block, i) || TransformCSharp4PostIncDecOperatorOnAddress(block, i)) {
block.Instructions.RemoveAt(i);
continue;
}
if (TransformPostIncDecOperator(block, i)) {
block.Instructions.RemoveAt(i);
continue;
}*/
if (TransformInlineAssignmentStObjOrCall(block, pos) || TransformInlineAssignmentLocal(block, pos)) {
// both inline assignments create a top-level stloc which might affect inlining
context.RequestRerun();
return;
}
/*
TransformInlineCompoundAssignmentCall(block, pos);
TransformRoslynCompoundAssignmentCall(block, pos);
// TODO: post-increment on local
// post-increment on address (e.g. field or array element)
TransformPostIncDecOperatorOnAddress(block, pos);
TransformRoslynPostIncDecOperatorOnAddress(block, pos);
// TODO: post-increment on call
*/
}
/// <code>
/// stloc s(value)
/// stloc l(ldloc s)
/// stobj(..., ldloc s)
/// where ... is pure and does not use s or l
/// -->
/// stloc l(stobj (..., value))
/// </code>
/// e.g. used for inline assignment to instance field
///
/// -or-
///
/// <code>
/// stloc s(value)
/// stobj (..., ldloc s)
/// -->
/// stloc s(stobj (..., value))
/// </code>
/// e.g. used for inline assignment to static field
///
/// -or-
///
/// <code>
/// stloc s(value)
/// call set_Property(..., ldloc s)
/// where the '...' arguments are free of side-effects and not using 's'
/// -->
/// stloc s(Block InlineAssign { call set_Property(..., stloc i(value)); final: ldloc i })
/// </code>
bool TransformInlineAssignmentStObjOrCall(Block block, int pos)
{
var inst = block.Instructions[pos] as StLoc;
// in some cases it can be a compiler-generated local
if (inst == null || (inst.Variable.Kind != VariableKind.StackSlot && inst.Variable.Kind != VariableKind.Local))
return false;
if (IsImplicitTruncation(inst.Value, inst.Variable.Type)) {
// 'stloc s' is implicitly truncating the value
return false;
}
ILVariable local;
int nextPos;
if (block.Instructions[pos + 1] is StLoc localStore) { // with extra local
if (localStore.Variable.Kind != VariableKind.Local || !localStore.Value.MatchLdLoc(inst.Variable))
return false;
if (!(inst.Variable.IsSingleDefinition && inst.Variable.LoadCount == 2))
return false;
local = localStore.Variable;
nextPos = pos + 2;
} else {
local = inst.Variable;
localStore = null;
nextPos = pos + 1;
}
if (block.Instructions[nextPos] is StObj stobj) {
if (!stobj.Value.MatchLdLoc(inst.Variable))
return false;
if (!SemanticHelper.IsPure(stobj.Target.Flags) || inst.Variable.IsUsedWithin(stobj.Target))
return false;
if (IsImplicitTruncation(inst.Value, stobj.Type)) {
// 'stobj' is implicitly truncating the value
return false;
}
context.Step("Inline assignment stobj", stobj);
block.Instructions.Remove(localStore);
block.Instructions.Remove(stobj);
stobj.Value = inst.Value;
inst.ReplaceWith(new StLoc(local, stobj));
return true;
} else if (block.Instructions[nextPos] is CallInstruction call) {
// call must be a setter call:
if (!(call.OpCode == OpCode.Call || call.OpCode == OpCode.CallVirt))
return false;
if (call.ResultType != StackType.Void || call.Arguments.Count == 0)
return false;
if (!call.Method.Equals((call.Method.AccessorOwner as IProperty)?.Setter))
return false;
if (!call.Arguments.Last().MatchLdLoc(inst.Variable))
return false;
foreach (var arg in call.Arguments.SkipLast(1)) {
if (!SemanticHelper.IsPure(arg.Flags) || inst.Variable.IsUsedWithin(arg))
return false;
}
if (IsImplicitTruncation(inst.Value, call.Method.Parameters.Last().Type)) {
// setter call is implicitly truncating the value
return false;
}
// stloc s(Block InlineAssign { call set_Property(..., stloc i(value)); final: ldloc i })
context.Step("Inline assignment call", call);
block.Instructions.Remove(localStore);
block.Instructions.Remove(call);
var newVar = context.Function.RegisterVariable(VariableKind.StackSlot, call.Method.Parameters.Last().Type);
call.Arguments[call.Arguments.Count - 1] = new StLoc(newVar, inst.Value);
inst.ReplaceWith(new StLoc(local, new Block(BlockType.CallInlineAssign) {
Instructions = { call },
FinalInstruction = new LdLoc(newVar)
}));
return true;
} else {
return false;
}
}
static ILInstruction UnwrapSmallIntegerConv(ILInstruction inst, out Conv conv)
{
conv = inst as Conv;
if (conv != null && conv.Kind == ConversionKind.Truncate && conv.TargetType.IsSmallIntegerType()) {
// for compound assignments to small integers, the compiler emits a "conv" instruction
return conv.Argument;
} else {
return inst;
}
}
static bool ValidateCompoundAssign(BinaryNumericInstruction binary, Conv conv, IType targetType)
{
if (!CompoundAssignmentInstruction.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 = UnwrapSmallIntegerConv(mainStLoc.Value, out var conv) 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;
IType targetType = getterCall.Method.ReturnType;
if (!ValidateCompoundAssign(binary, conv, targetType))
return false;
context.Step($"Inline compound assignment to '{getterCall.Method.AccessorOwner.Name}'", setterCall);
block.Instructions.RemoveAt(i + 1); // remove setter call
mainStLoc.Value = new CompoundAssignmentInstruction(
binary, getterCall, binary.Right,
targetType, CompoundAssignmentType.EvaluatesToNewValue);
return true;
}
/// <summary>
/// Roslyn compound assignment that's not inline within another instruction.
/// </summary>
bool TransformRoslynCompoundAssignmentCall(Block block, int i)
{
// stloc variable(callvirt get_Property(ldloc obj))
// callvirt set_Property(ldloc obj, binary.op(ldloc variable, ldc.i4 1))
// => compound.op.new(callvirt get_Property(ldloc obj), ldc.i4 1)
if (!(block.Instructions[i] is StLoc stloc))
return false;
if (!(stloc.Variable.IsSingleDefinition && stloc.Variable.LoadCount == 1))
return false;
var getterCall = stloc.Value as CallInstruction;
var setterCall = block.Instructions[i + 1] as CallInstruction;
if (!(MatchingGetterAndSetterCalls(getterCall, setterCall)))
return false;
var binary = setterCall.Arguments.Last() as BinaryNumericInstruction;
if (binary == null || !binary.Left.MatchLdLoc(stloc.Variable))
return false;
if (!CompoundAssignmentInstruction.IsBinaryCompatibleWithType(binary, getterCall.Method.ReturnType))
return false;
context.Step($"Compound assignment to '{getterCall.Method.AccessorOwner.Name}'", setterCall);
block.Instructions.RemoveAt(i + 1); // remove setter call
stloc.ReplaceWith(new CompoundAssignmentInstruction(
binary, getterCall, binary.Right,
getterCall.Method.ReturnType, CompoundAssignmentType.EvaluatesToNewValue));
return true;
}
static bool MatchingGetterAndSetterCalls(CallInstruction getterCall, CallInstruction setterCall)
{
if (getterCall == null || setterCall == null || !IsSameMember(getterCall.Method.AccessorOwner, setterCall.Method.AccessorOwner))
return false;
var owner = getterCall.Method.AccessorOwner as IProperty;
if (owner == null || !IsSameMember(getterCall.Method, owner.Getter) || !IsSameMember(setterCall.Method, owner.Setter))
return false;
if (setterCall.Arguments.Count != getterCall.Arguments.Count + 1)
return false;
// Ensure that same arguments are passed to getterCall and setterCall:
for (int j = 0; j < getterCall.Arguments.Count; j++) {
if (!SemanticHelper.IsPure(getterCall.Arguments[j].Flags))
return false;
if (!getterCall.Arguments[j].Match(setterCall.Arguments[j]).Success)
return false;
}
return true;
}
/// <summary>
/// Transform compound assignments where the return value is not being used,
/// or where there's an inlined assignment within the setter call.
/// </summary>
/// <remarks>
/// Called by ExpressionTransforms.
/// </remarks>
internal static bool HandleCallCompoundAssign(CallInstruction setterCall, StatementTransformContext context)
{
// callvirt set_Property(ldloc S_1, binary.op(callvirt get_Property(ldloc S_1), value))
// ==> compound.op.new(callvirt(callvirt get_Property(ldloc S_1)), value)
var setterValue = setterCall.Arguments.LastOrDefault();
var storeInSetter = setterValue as StLoc;
if (storeInSetter != null) {
// callvirt set_Property(ldloc S_1, stloc v(binary.op(callvirt get_Property(ldloc S_1), value)))
// ==> stloc v(compound.op.new(callvirt(callvirt get_Property(ldloc S_1)), value))
setterValue = storeInSetter.Value;
}
if (setterValue is Conv conv && conv.Kind == ConversionKind.Truncate && conv.TargetType.IsSmallIntegerType()) {
// for compound assignments to small integers, the compiler emits a "conv" instruction
setterValue = conv.Argument;
} else {
conv = null;
}
if (!(setterValue is BinaryNumericInstruction binary))
return false;
var getterCall = binary.Left as CallInstruction;
if (!MatchingGetterAndSetterCalls(getterCall, setterCall))
return false;
IType targetType = getterCall.Method.ReturnType;
if (!CompoundAssignmentInstruction.IsBinaryCompatibleWithType(binary, targetType))
return false;
if (conv != null && !(conv.TargetType == targetType.ToPrimitiveType() && conv.CheckForOverflow == binary.CheckForOverflow))
return false; // conv does not match binary operation
context.Step($"Compound assignment to '{getterCall.Method.AccessorOwner.Name}'", setterCall);
ILInstruction newInst = new CompoundAssignmentInstruction(
binary, getterCall, binary.Right,
getterCall.Method.ReturnType, CompoundAssignmentType.EvaluatesToNewValue);
if (storeInSetter != null) {
storeInSetter.Value = newInst;
newInst = storeInSetter;
context.RequestRerun(); // moving stloc to top-level might trigger inlining
}
setterCall.ReplaceWith(newInst);
return true;
}
/// <summary>
/// stobj(target, binary.op(ldobj(target), ...))
/// => compound.op(target, ...)
/// </summary>
/// <remarks>
/// Called by ExpressionTransforms.
/// </remarks>
internal static bool HandleStObjCompoundAssign(StObj inst, ILTransformContext context)
{
if (!(UnwrapSmallIntegerConv(inst.Value, out var conv) is BinaryNumericInstruction binary))
return false;
if (!(binary.Left is LdObj ldobj))
return false;
if (!inst.Target.Match(ldobj.Target).Success)
return false;
if (!SemanticHelper.IsPure(ldobj.Target.Flags))
return false;
// ldobj.Type may just be 'int' (due to ldind.i4) when we're actually operating on a 'ref MyEnum'.
// Try to determine the real type of the object we're modifying:
IType targetType = ldobj.Target.InferType();
if (targetType.Kind == TypeKind.Pointer || targetType.Kind == TypeKind.ByReference) {
targetType = ((TypeWithElementType)targetType).ElementType;
if (targetType.Kind == TypeKind.Unknown || targetType.GetSize() != ldobj.Type.GetSize()) {
targetType = ldobj.Type;
}
} else {
targetType = ldobj.Type;
}
if (!ValidateCompoundAssign(binary, conv, targetType))
return false;
context.Step("compound assignment", inst);
inst.ReplaceWith(new CompoundAssignmentInstruction(
binary, binary.Left, binary.Right,
targetType, CompoundAssignmentType.EvaluatesToNewValue));
return true;
}
/// <code>
/// stloc s(value)
/// stloc l(ldloc s)
/// -->
/// stloc s(stloc l(value))
/// </code>
bool TransformInlineAssignmentLocal(Block block, int pos)
{
var inst = block.Instructions[pos] as StLoc;
var nextInst = block.Instructions.ElementAtOrDefault(pos + 1) as StLoc;
if (inst == null || nextInst == null)
return false;
if (inst.Variable.Kind != VariableKind.StackSlot)
return false;
Debug.Assert(!inst.Variable.Type.IsSmallIntegerType());
if (!(nextInst.Variable.Kind == VariableKind.Local || nextInst.Variable.Kind == VariableKind.Parameter))
return false;
if (!nextInst.Value.MatchLdLoc(inst.Variable))
return false;
if (IsImplicitTruncation(inst.Value, nextInst.Variable.Type)) {
// 'stloc l' is implicitly truncating the stack value
return false;
}
context.Step("Inline assignment to local variable", inst);
var value = inst.Value;
var var = nextInst.Variable;
var stackVar = inst.Variable;
block.Instructions.RemoveAt(pos);
nextInst.ReplaceWith(new StLoc(stackVar, new StLoc(var, value)));
return true;
}
/// <summary>
/// Gets whether 'stobj type(..., value)' would evaluate to a different value than 'value'
/// due to implicit truncation.
/// </summary>
bool IsImplicitTruncation(ILInstruction value, IType type)
{
if (!type.IsSmallIntegerType()) {
// Implicit truncation in ILAst only happens for small integer types;
// other types of implicit truncation in IL cause the ILReader to insert
// conv instructions.
return false;
}
// With small integer types, test whether the value might be changed by
// truncation (based on type.GetSize()) followed by sign/zero extension (based on type.GetSign()).
// (it's OK to have false-positives here if we're unsure)
if (value.MatchLdcI4(out int val)) {
switch (type.GetEnumUnderlyingType().GetDefinition()?.KnownTypeCode) {
case KnownTypeCode.Boolean:
return !(val == 0 || val == 1);
case KnownTypeCode.Byte:
return !(val >= byte.MinValue && val <= byte.MaxValue);
case KnownTypeCode.SByte:
return !(val >= sbyte.MinValue && val <= sbyte.MaxValue);
case KnownTypeCode.Int16:
return !(val >= short.MinValue && val <= short.MaxValue);
case KnownTypeCode.UInt16:
case KnownTypeCode.Char:
return !(val >= ushort.MinValue && val <= ushort.MaxValue);
}
} else if (value is Conv conv) {
return conv.TargetType != type.ToPrimitiveType();
} else if (value is Comp) {
return false; // comp returns 0 or 1, which always fits
} else {
IType inferredType = value.InferType();
if (inferredType.Kind != TypeKind.Unknown) {
return !(inferredType.GetSize() <= type.GetSize() && inferredType.GetSign() == type.GetSign());
}
}
return true;
}
/// <code>
/// stloc s(ldloc l)
/// stloc l(binary.op(ldloc s, ldc.i4 1))
/// -->
/// stloc s(block {
/// stloc s2(ldloc l)
/// stloc l(binary.op(ldloc s2, ldc.i4 1))
/// final: ldloc s2
/// })
/// </code>
bool TransformPostIncDecOperator(Block block, int i)
{
var inst = block.Instructions[i] as StLoc;
var nextInst = block.Instructions.ElementAtOrDefault(i + 1) as StLoc;
if (inst == null || nextInst == null || !inst.Value.MatchLdLoc(out var l) || !ILVariableEqualityComparer.Instance.Equals(l, nextInst.Variable))
return false;
var binary = nextInst.Value as BinaryNumericInstruction;
if (inst.Variable.Kind != VariableKind.StackSlot || nextInst.Variable.Kind == VariableKind.StackSlot || binary == null)
return false;
if (binary.IsLifted)
return false;
if ((binary.Operator != BinaryNumericOperator.Add && binary.Operator != BinaryNumericOperator.Sub) || !binary.Left.MatchLdLoc(inst.Variable) || !binary.Right.MatchLdcI4(1))
return false;
context.Step($"TransformPostIncDecOperator", inst);
var tempStore = context.Function.RegisterVariable(VariableKind.StackSlot, inst.Variable.Type);
var assignment = new Block(BlockType.PostfixOperator);
assignment.Instructions.Add(new StLoc(tempStore, new LdLoc(nextInst.Variable)));
assignment.Instructions.Add(new StLoc(nextInst.Variable, new BinaryNumericInstruction(binary.Operator, new LdLoc(tempStore), new LdcI4(1), binary.CheckForOverflow, binary.Sign)));
assignment.FinalInstruction = new LdLoc(tempStore);
nextInst.ReplaceWith(new StLoc(inst.Variable, assignment));
return true;
}
/// <code>
/// stobj(target, binary.add(stloc l(ldobj(target)), ldc.i4 1))
/// where target is pure and does not use 'l'
/// -->
/// stloc l(compound.op.old(ldobj(target), ldc.i4 1))
/// </code>
bool TransformPostIncDecOperatorOnAddress(Block block, int i)
{
if (!(block.Instructions[i] is StObj stobj))
return false;
var binary = UnwrapSmallIntegerConv(stobj.Value, out var conv) as BinaryNumericInstruction;
if (binary == null || !binary.Right.MatchLdcI4(1))
return false;
if (!(binary.Operator == BinaryNumericOperator.Add || binary.Operator == BinaryNumericOperator.Sub))
return false;
if (!(binary.Left is StLoc stloc))
return false;
if (!(stloc.Variable.Kind == VariableKind.Local || stloc.Variable.Kind == VariableKind.StackSlot))
return false;
if (!(stloc.Value is LdObj ldobj))
return false;
if (!SemanticHelper.IsPure(ldobj.Target.Flags))
return false;
if (!ldobj.Target.Match(stobj.Target).Success)
return false;
if (stloc.Variable.IsUsedWithin(ldobj.Target))
return false;
IType targetType = ldobj.Type;
if (!ValidateCompoundAssign(binary, conv, targetType))
return false;
context.Step("TransformPostIncDecOperatorOnAddress", stobj);
block.Instructions[i] = new StLoc(stloc.Variable, new CompoundAssignmentInstruction(
binary, ldobj, binary.Right, targetType, CompoundAssignmentType.EvaluatesToOldValue));
return true;
}
/// <code>
/// stloc l(ldobj(target))
/// stobj(target, binary.op(ldloc l, ldc.i4 1))
/// target is pure and does not use 'l'
/// -->
/// stloc l(compound.op.old(ldobj(target), ldc.i4 1))
/// </code>
bool TransformRoslynPostIncDecOperatorOnAddress(Block block, int i)
{
var inst = block.Instructions[i] as StLoc;
var stobj = block.Instructions.ElementAtOrDefault(i + 1) as StObj;
if (inst == null || stobj == null)
return false;
if (!(inst.Value is LdObj ldobj))
return false;
if (!SemanticHelper.IsPure(ldobj.Target.Flags))
return false;
if (!ldobj.Target.Match(stobj.Target).Success)
return false;
if (inst.Variable.IsUsedWithin(ldobj.Target))
return false;
var binary = UnwrapSmallIntegerConv(stobj.Value, out var conv) as BinaryNumericInstruction;
if (binary == null || !binary.Left.MatchLdLoc(inst.Variable) || !binary.Right.MatchLdcI4(1))
return false;
if (!(binary.Operator == BinaryNumericOperator.Add || binary.Operator == BinaryNumericOperator.Sub))
return false;
var targetType = ldobj.Type;
if (!ValidateCompoundAssign(binary, conv, targetType))
return false;
context.Step("TransformRoslynPostIncDecOperatorOnAddress", inst);
inst.Value = new CompoundAssignmentInstruction(binary, inst.Value, binary.Right, targetType, CompoundAssignmentType.EvaluatesToOldValue);
block.Instructions.RemoveAt(i + 1);
return true;
}
/// <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($"TransformCSharp4PostIncDecOperatorOnAddress", baseFieldAddress);
var assignment = new CompoundAssignmentInstruction(binary, new LdObj(baseAddress, t), binary.Right, t, CompoundAssignmentType.EvaluatesToOldValue);
stobj.ReplaceWith(new StLoc(fieldValueCopyToLocal.Variable, assignment));
block.Instructions.RemoveAt(i + 2);
block.Instructions.RemoveAt(i + 1);
return true;
}
/// <code>
/// stloc s(ldobj(ldsflda))
/// stobj (ldsflda, binary.op(ldloc s, ldc.i4 1))
/// -->
/// stloc s(compound.op.old(ldobj(ldsflda), ldc.i4 1))
/// </code>
bool TransformPostIncDecOnStaticField(Block block, int i)
{
var inst = block.Instructions[i] as StLoc;
var stobj = block.Instructions.ElementAtOrDefault(i + 1) as StObj;
if (inst == null || stobj == null)
return false;
ILInstruction target;
IType type;
IField field, field2;
if (inst.Variable.Kind != VariableKind.StackSlot || !inst.Value.MatchLdObj(out target, out type) || !target.MatchLdsFlda(out field))
return false;
if (!stobj.Target.MatchLdsFlda(out field2) || !IsSameMember(field, field2))
return false;
var binary = stobj.Value as BinaryNumericInstruction;
if (binary == null || !binary.Left.MatchLdLoc(inst.Variable) || !binary.Right.MatchLdcI4(1))
return false;
context.Step($"TransformPostIncDecOnStaticField", inst);
var assignment = new CompoundAssignmentInstruction(binary, inst.Value, binary.Right, type, CompoundAssignmentType.EvaluatesToOldValue);
stobj.ReplaceWith(new StLoc(inst.Variable, assignment));
return true;
}
static bool IsSameMember(IMember a, IMember b)
{
if (a == null || b == null)
return false;
a = a.MemberDefinition;
b = b.MemberDefinition;
return a.Equals(b);
}
}
}