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361 lines
15 KiB
361 lines
15 KiB
// Copyright (c) 2015 Siegfried Pammer |
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// |
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this |
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// software and associated documentation files (the "Software"), to deal in the Software |
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// without restriction, including without limitation the rights to use, copy, modify, merge, |
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons |
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// to whom the Software is furnished to do so, subject to the following conditions: |
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// |
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// The above copyright notice and this permission notice shall be included in all copies or |
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// substantial portions of the Software. |
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// |
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, |
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR |
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE |
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// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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// DEALINGS IN THE SOFTWARE. |
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using System; |
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using System.Collections.Generic; |
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using System.Linq; |
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using ICSharpCode.NRefactory.TypeSystem; |
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using ICSharpCode.NRefactory.TypeSystem.Implementation; |
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namespace ICSharpCode.Decompiler.IL.Transforms |
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{ |
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/// <summary> |
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/// Description of TransformAssignment. |
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/// </summary> |
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public class TransformAssignment : IILTransform |
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{ |
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ILTransformContext context; |
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void IILTransform.Run(ILFunction function, ILTransformContext context) |
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{ |
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this.context = context; |
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foreach (var block in function.Descendants.OfType<Block>()) { |
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for (int i = block.Instructions.Count - 1; i >= 0; i--) { |
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if (TransformPostIncDecOperatorOnAddress(block, i) || TransformPostIncDecOnStaticField(block, i) || TransformCSharp4PostIncDecOperatorOnAddress(block, i)) { |
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block.Instructions.RemoveAt(i); |
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continue; |
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} |
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if (InlineLdAddressUsages(block, i)) { |
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block.Instructions.RemoveAt(i); |
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continue; |
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} |
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if (TransformPostIncDecOperator(block, i, function)) { |
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block.Instructions.RemoveAt(i); |
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continue; |
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} |
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if (TransformInlineAssignmentStObj(block, i)) |
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continue; |
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if (TransformInlineAssignmentCall(block, i)) |
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continue; |
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} |
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} |
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} |
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/// <code> |
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/// stloc s(value) |
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/// stloc l(ldloc s) |
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/// stobj(..., ldloc s) |
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/// --> |
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/// stloc l(stobj (..., value)) |
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/// </code> |
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/// -or- |
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/// <code> |
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/// stloc s(value) |
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/// stobj (..., ldloc s) |
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/// --> |
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/// stloc s(stobj (..., value)) |
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/// </code> |
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static bool TransformInlineAssignmentStObj(Block block, int i) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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// in some cases it can be a compiler-generated local |
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if (inst == null || (inst.Variable.Kind != VariableKind.StackSlot && inst.Variable.Kind != VariableKind.Local)) |
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return false; |
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var nextInst = block.Instructions.ElementAtOrDefault(i + 1); |
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ILInstruction replacement; |
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StObj fieldStore; |
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ILVariable local; |
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if (nextInst is StLoc) { // instance fields |
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var localStore = (StLoc)nextInst; |
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if (localStore.Variable.Kind == VariableKind.StackSlot || !localStore.Value.MatchLdLoc(inst.Variable)) |
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return false; |
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var memberStore = block.Instructions.ElementAtOrDefault(i + 2); |
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if (memberStore is StObj) { |
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fieldStore = memberStore as StObj; |
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if (!fieldStore.Value.MatchLdLoc(inst.Variable)) |
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return false; |
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replacement = new StObj(fieldStore.Target, inst.Value, fieldStore.Type); |
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} else { // otherwise it must be local |
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TransformInlineAssignmentLocal(block, i); |
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return false; |
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} |
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local = localStore.Variable; |
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block.Instructions.RemoveAt(i + 1); |
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} else if (nextInst is StObj) { // static fields |
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fieldStore = (StObj)nextInst; |
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if (!fieldStore.Value.MatchLdLoc(inst.Variable)) |
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return false; |
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local = inst.Variable; |
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replacement = new StObj(fieldStore.Target, inst.Value, fieldStore.Type); |
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} else return false; |
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block.Instructions.RemoveAt(i + 1); |
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inst.ReplaceWith(new StLoc(local, replacement)); |
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return true; |
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} |
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/// <code> |
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/// stloc s(binary(callvirt(getter), value)) |
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/// callvirt (setter, ldloc s) |
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/// ... usage of s ... |
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/// --> |
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/// ... compound.op.new(callvirt(getter), value) ... |
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/// </code> |
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/// -or- |
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/// <code> |
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/// stloc s(stloc v(binary(callvirt(getter), value))) |
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/// callvirt (setter, ldloc s) |
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/// ... usage of v ... |
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/// --> |
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/// ... compound.op.new(callvirt(getter), value) ... |
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/// </code> |
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static bool TransformInlineAssignmentCall(Block block, int i) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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// in some cases it can be a compiler-generated local |
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if (inst == null || (inst.Variable.Kind != VariableKind.StackSlot && inst.Variable.Kind != VariableKind.Local)) |
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return false; |
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BinaryNumericInstruction binary; |
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ILVariable localVariable; |
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if (inst.Value is StLoc) { |
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var tmp = (StLoc)inst.Value; |
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binary = tmp.Value as BinaryNumericInstruction; |
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localVariable = tmp.Variable; |
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} else { |
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binary = inst.Value as BinaryNumericInstruction; |
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localVariable = inst.Variable; |
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} |
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var getterCall = binary?.Left as CallInstruction; |
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var setterCall = block.Instructions.ElementAtOrDefault(i + 1) as CallInstruction; |
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if (getterCall == null || setterCall == null || !IsSameMember(getterCall.Method.AccessorOwner, setterCall.Method.AccessorOwner)) |
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return false; |
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var owner = getterCall.Method.AccessorOwner as IProperty; |
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if (owner == null || !IsSameMember(getterCall.Method, owner.Getter) || !IsSameMember(setterCall.Method, owner.Setter)) |
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return false; |
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var next = block.Instructions.ElementAtOrDefault(i + 2); |
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if (next == null) |
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return false; |
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var usages = next.Descendants.Where(d => d.MatchLdLoc(localVariable)).ToArray(); |
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if (usages.Length != 1) |
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return false; |
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block.Instructions.RemoveAt(i + 1); |
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block.Instructions.RemoveAt(i); |
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usages[0].ReplaceWith(new CompoundAssignmentInstruction(binary.Operator, getterCall, binary.Right, |
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getterCall.Method.ReturnType, binary.CheckForOverflow, binary.Sign, CompoundAssignmentType.EvaluatesToNewValue)); |
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return true; |
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} |
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/// <code> |
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/// stloc s(value) |
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/// stloc l(ldloc s) |
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/// --> |
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/// stloc s(stloc l(value)) |
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/// </code> |
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static void TransformInlineAssignmentLocal(Block block, int i) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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var nextInst = block.Instructions.ElementAtOrDefault(i + 1) as StLoc; |
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if (inst == null || nextInst == null) |
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return; |
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if (nextInst.Variable.Kind == VariableKind.StackSlot || !nextInst.Value.MatchLdLoc(inst.Variable)) |
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return; |
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var value = inst.Value; |
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var var = nextInst.Variable; |
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var stackVar = inst.Variable; |
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block.Instructions.RemoveAt(i); |
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nextInst.ReplaceWith(new StLoc(stackVar, new StLoc(var, value))); |
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} |
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/// ldaddress ::= ldelema | ldflda | ldsflda; |
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/// <code> |
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/// stloc s(ldaddress) |
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/// usages of ldobj(ldloc s) or stobj(ldloc s, ...) in next instruction |
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/// --> |
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/// use ldaddress instead of ldloc s |
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/// </code> |
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static bool InlineLdAddressUsages(Block block, int i) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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if (inst == null || inst.Variable.Kind != VariableKind.StackSlot || !(inst.Value is LdElema || inst.Value is LdFlda || inst.Value is LdsFlda)) |
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return false; |
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var valueToCopy = inst.Value; |
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var nextInstruction = inst.Parent.Children.ElementAtOrDefault(inst.ChildIndex + 1); |
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if (nextInstruction == null) |
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return false; |
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var affectedUsages = block.Descendants |
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.OfType<IInstructionWithVariableOperand>() |
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.Where(ins => ins != inst) |
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.Where(ins => ins.Variable == inst.Variable) |
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.Cast<ILInstruction>().ToArray(); |
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if (affectedUsages.Length == 0 || affectedUsages.Any(ins => !(ins.Parent is StObj || ins.Parent is LdObj))) |
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return false; |
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foreach (var usage in affectedUsages) { |
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usage.ReplaceWith(valueToCopy.Clone()); |
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} |
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return true; |
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} |
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/// <code> |
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/// stloc s(ldloc l) |
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/// stloc l(binary.op(ldloc s, ldc.i4 1)) |
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/// --> |
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/// stloc s(block { |
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/// stloc s2(ldloc l) |
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/// stloc l(binary.op(ldloc s2, ldc.i4 1)) |
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/// final: ldloc s2 |
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/// }) |
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/// </code> |
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static bool TransformPostIncDecOperator(Block block, int i, ILFunction function) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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var nextInst = block.Instructions.ElementAtOrDefault(i + 1) as StLoc; |
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if (inst == null || nextInst == null) |
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return false; |
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var binary = nextInst.Value as BinaryNumericInstruction; |
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if (inst.Variable.Kind != VariableKind.StackSlot || nextInst.Variable.Kind == VariableKind.StackSlot || binary == null) |
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return false; |
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if ((binary.Operator != BinaryNumericOperator.Add && binary.Operator != BinaryNumericOperator.Sub) || !binary.Left.MatchLdLoc(inst.Variable) || !binary.Right.MatchLdcI4(1)) |
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return false; |
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var tempStore = function.RegisterVariable(VariableKind.StackSlot, inst.Variable.Type); |
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var assignment = new Block(BlockType.CompoundOperator); |
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assignment.Instructions.Add(new StLoc(tempStore, new LdLoc(nextInst.Variable))); |
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assignment.Instructions.Add(new StLoc(nextInst.Variable, new BinaryNumericInstruction(binary.Operator, new LdLoc(tempStore), new LdcI4(1), binary.CheckForOverflow, binary.Sign))); |
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assignment.FinalInstruction = new LdLoc(tempStore); |
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nextInst.ReplaceWith(new StLoc(inst.Variable, assignment)); |
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return true; |
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} |
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/// ldaddress ::= ldelema | ldflda | ldsflda; |
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/// <code> |
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/// stloc s(ldaddress) |
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/// stloc l(ldobj(ldloc s)) |
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/// stobj(ldloc s, binary.op(ldloc l, ldc.i4 1)) |
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/// --> |
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/// stloc l(compound.op.old(ldobj(ldaddress), ldc.i4 1)) |
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/// </code> |
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static bool TransformPostIncDecOperatorOnAddress(Block block, int i) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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var nextInst = block.Instructions.ElementAtOrDefault(i + 1) as StLoc; |
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var stobj = block.Instructions.ElementAtOrDefault(i + 2) as StObj; |
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if (inst == null || nextInst == null || stobj == null) |
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return false; |
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if (!(inst.Value is LdElema || inst.Value is LdFlda || inst.Value is LdsFlda)) |
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return false; |
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ILInstruction target; |
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IType targetType; |
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if (nextInst.Variable.Kind == VariableKind.StackSlot || !nextInst.Value.MatchLdObj(out target, out targetType) || !target.MatchLdLoc(inst.Variable)) |
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return false; |
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if (!stobj.Target.MatchLdLoc(inst.Variable)) |
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return false; |
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var binary = stobj.Value as BinaryNumericInstruction; |
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if (binary == null || !binary.Left.MatchLdLoc(nextInst.Variable) || !binary.Right.MatchLdcI4(1) |
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|| (binary.Operator != BinaryNumericOperator.Add && binary.Operator != BinaryNumericOperator.Sub)) |
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return false; |
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var assignment = new CompoundAssignmentInstruction(binary.Operator, new LdObj(inst.Value, targetType), binary.Right, targetType, binary.CheckForOverflow, binary.Sign, CompoundAssignmentType.EvaluatesToOldValue); |
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stobj.ReplaceWith(new StLoc(nextInst.Variable, assignment)); |
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block.Instructions.RemoveAt(i + 1); |
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return true; |
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} |
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/// <code> |
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/// stloc s(ldflda) |
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/// stloc s2(ldobj(ldflda(ldloc s))) |
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/// stloc l(ldloc s2) |
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/// stobj (ldflda(ldloc s), binary.add(ldloc s2, ldc.i4 1)) |
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/// --> |
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/// stloc l(compound.op.old(ldobj(ldflda(ldflda)), ldc.i4 1)) |
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/// </code> |
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static bool TransformCSharp4PostIncDecOperatorOnAddress(Block block, int i) |
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{ |
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var baseFieldAddress = block.Instructions[i] as StLoc; |
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var fieldValue = block.Instructions.ElementAtOrDefault(i + 1) as StLoc; |
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var fieldValueCopyToLocal = block.Instructions.ElementAtOrDefault(i + 2) as StLoc; |
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var stobj = block.Instructions.ElementAtOrDefault(i + 3) as StObj; |
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if (baseFieldAddress == null || fieldValue == null || fieldValueCopyToLocal == null || stobj == null) |
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return false; |
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if (baseFieldAddress.Variable.Kind != VariableKind.StackSlot || fieldValue.Variable.Kind != VariableKind.StackSlot || fieldValueCopyToLocal.Variable.Kind != VariableKind.Local) |
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return false; |
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IType t; |
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IField targetField; |
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ILInstruction targetFieldLoad, baseFieldAddressLoad2; |
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if (!fieldValue.Value.MatchLdObj(out targetFieldLoad, out t)) |
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return false; |
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ILInstruction baseAddress; |
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if (baseFieldAddress.Value is LdFlda) { |
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IField targetField2; |
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ILInstruction baseFieldAddressLoad3; |
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if (!targetFieldLoad.MatchLdFlda(out baseFieldAddressLoad2, out targetField) || !baseFieldAddressLoad2.MatchLdLoc(baseFieldAddress.Variable)) |
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return false; |
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if (!stobj.Target.MatchLdFlda(out baseFieldAddressLoad3, out targetField2) || !baseFieldAddressLoad3.MatchLdLoc(baseFieldAddress.Variable) || !IsSameMember(targetField, targetField2)) |
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return false; |
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baseAddress = new LdFlda(baseFieldAddress.Value, targetField); |
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} else if (baseFieldAddress.Value is LdElema) { |
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if (!targetFieldLoad.MatchLdLoc(baseFieldAddress.Variable) || !stobj.Target.MatchLdLoc(baseFieldAddress.Variable)) |
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return false; |
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baseAddress = baseFieldAddress.Value; |
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} else { |
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return false; |
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} |
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BinaryNumericInstruction binary = stobj.Value as BinaryNumericInstruction; |
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if (binary == null || !binary.Left.MatchLdLoc(fieldValue.Variable) || !binary.Right.MatchLdcI4(1) |
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|| (binary.Operator != BinaryNumericOperator.Add && binary.Operator != BinaryNumericOperator.Sub)) |
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return false; |
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var assignment = new CompoundAssignmentInstruction(binary.Operator, new LdObj(baseAddress, t), binary.Right, t, binary.CheckForOverflow, binary.Sign, CompoundAssignmentType.EvaluatesToOldValue); |
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stobj.ReplaceWith(new StLoc(fieldValueCopyToLocal.Variable, assignment)); |
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block.Instructions.RemoveAt(i + 2); |
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block.Instructions.RemoveAt(i + 1); |
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return true; |
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} |
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/// <code> |
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/// stloc s(ldobj(ldsflda)) |
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/// stobj (ldsflda, binary.op(ldloc s, ldc.i4 1)) |
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/// --> |
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/// stloc s(compound.op.old(ldobj(ldsflda), ldc.i4 1)) |
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/// </code> |
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static bool TransformPostIncDecOnStaticField(Block block, int i) |
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{ |
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var inst = block.Instructions[i] as StLoc; |
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var stobj = block.Instructions.ElementAtOrDefault(i + 1) as StObj; |
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if (inst == null || stobj == null) |
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return false; |
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ILInstruction target; |
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IType type; |
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IField field, field2; |
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if (inst.Variable.Kind != VariableKind.StackSlot || !inst.Value.MatchLdObj(out target, out type) || !target.MatchLdsFlda(out field)) |
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return false; |
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if (!stobj.Target.MatchLdsFlda(out field2) || !IsSameMember(field, field2)) |
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return false; |
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var binary = stobj.Value as BinaryNumericInstruction; |
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if (binary == null || !binary.Left.MatchLdLoc(inst.Variable) || !binary.Right.MatchLdcI4(1)) |
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return false; |
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var assignment = new CompoundAssignmentInstruction(binary.Operator, inst.Value, binary.Right, type, binary.CheckForOverflow, binary.Sign, CompoundAssignmentType.EvaluatesToOldValue); |
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stobj.ReplaceWith(new StLoc(inst.Variable, assignment)); |
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return true; |
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} |
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static bool IsSameMember(IMember a, IMember b) |
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{ |
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if (a == null || b == null) |
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return false; |
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a = a.MemberDefinition; |
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b = b.MemberDefinition; |
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return a.Equals(b); |
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} |
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} |
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}
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