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459 lines
14 KiB
459 lines
14 KiB
// Copyright (c) 2021 Daniel Grunwald, 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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#nullable enable |
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using System; |
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using System.Diagnostics; |
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using System.Diagnostics.CodeAnalysis; |
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using System.Linq; |
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using System.Reflection; |
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using ICSharpCode.Decompiler.IL.ControlFlow; |
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using ICSharpCode.Decompiler.TypeSystem; |
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using ICSharpCode.Decompiler.Util; |
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namespace ICSharpCode.Decompiler.IL.Transforms |
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{ |
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class PatternMatchingTransform : IILTransform |
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{ |
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void IILTransform.Run(ILFunction function, ILTransformContext context) |
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{ |
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if (!context.Settings.PatternMatching) |
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return; |
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foreach (var container in function.Descendants.OfType<BlockContainer>()) |
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{ |
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ControlFlowGraph? cfg = null; |
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foreach (var block in container.Blocks.Reverse()) |
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{ |
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if (PatternMatchValueTypes(block, container, context, ref cfg)) |
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{ |
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continue; |
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} |
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if (PatternMatchRefTypes(block, container, context, ref cfg)) |
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{ |
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continue; |
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} |
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} |
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} |
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} |
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/// Block { |
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/// ... |
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/// stloc V(isinst T(testedOperand)) |
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/// if (comp.o(ldloc V == ldnull)) br falseBlock |
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/// br trueBlock |
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/// } |
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/// |
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/// All other uses of V are in blocks dominated by trueBlock. |
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/// => |
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/// Block { |
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/// ... |
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/// if (match.type[T].notnull(V = testedOperand)) br trueBlock |
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/// br falseBlock |
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/// } |
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/// |
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/// - or - |
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/// |
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/// Block { |
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/// stloc s(isinst T(testedOperand)) |
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/// stloc v(ldloc s) |
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/// if (logic.not(comp.o(ldloc s != ldnull))) br falseBlock |
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/// br trueBlock |
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/// } |
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/// => |
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/// Block { |
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/// ... |
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/// if (match.type[T].notnull(V = testedOperand)) br trueBlock |
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/// br falseBlock |
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/// } |
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/// |
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/// All other uses of V are in blocks dominated by trueBlock. |
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private bool PatternMatchRefTypes(Block block, BlockContainer container, ILTransformContext context, ref ControlFlowGraph? cfg) |
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{ |
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if (!block.MatchIfAtEndOfBlock(out var condition, out var trueInst, out var falseInst)) |
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return false; |
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int pos = block.Instructions.Count - 3; |
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if (condition.MatchLdLoc(out var conditionVar)) |
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{ |
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// stloc conditionVar(comp.o(ldloc s == ldnull)) |
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// if (logic.not(ldloc conditionVar)) br trueBlock |
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if (pos < 0) |
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return false; |
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if (!(conditionVar.IsSingleDefinition && conditionVar.LoadCount == 1 |
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&& conditionVar.Kind == VariableKind.StackSlot)) |
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{ |
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return false; |
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} |
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if (!block.Instructions[pos].MatchStLoc(conditionVar, out condition)) |
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return false; |
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pos--; |
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} |
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if (condition.MatchCompEqualsNull(out var loadInNullCheck)) |
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{ |
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ExtensionMethods.Swap(ref trueInst, ref falseInst); |
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} |
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else if (condition.MatchCompNotEqualsNull(out loadInNullCheck)) |
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{ |
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// do nothing |
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} |
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else |
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{ |
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return false; |
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} |
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if (!loadInNullCheck.MatchLdLoc(out var s)) |
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return false; |
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if (!s.IsSingleDefinition) |
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return false; |
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if (s.Kind is not (VariableKind.Local or VariableKind.StackSlot)) |
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return false; |
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if (pos < 0) |
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return false; |
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// stloc V(isinst T(testedOperand)) |
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ILInstruction storeToV = block.Instructions[pos]; |
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if (!storeToV.MatchStLoc(out var v, out var value)) |
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return false; |
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if (value.MatchLdLoc(s)) |
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{ |
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// stloc v(ldloc s) |
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pos--; |
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if (pos < 0 || !block.Instructions[pos].MatchStLoc(s, out value)) |
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return false; |
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if (v.Kind is not (VariableKind.Local or VariableKind.StackSlot)) |
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return false; |
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if (s.LoadCount != 2) |
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return false; |
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} |
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else |
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{ |
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if (v != s) |
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return false; |
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} |
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IType? unboxType; |
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if (value is UnboxAny unboxAny) |
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{ |
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// stloc S(unbox.any T(isinst T(testedOperand))) |
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unboxType = unboxAny.Type; |
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value = unboxAny.Argument; |
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} |
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else |
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{ |
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unboxType = null; |
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} |
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if (value is not IsInst { Argument: var testedOperand, Type: var type }) |
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return false; |
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if (type.IsReferenceType != true) |
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return false; |
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if (!(unboxType == null || type.Equals(unboxType))) |
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return false; |
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if (!v.Type.Equals(type)) |
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return false; |
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if (!CheckAllUsesDominatedBy(v, container, trueInst, storeToV, loadInNullCheck, context, ref cfg)) |
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return false; |
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context.Step($"Type pattern matching {v.Name}", block); |
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// if (match.type[T].notnull(V = testedOperand)) br trueBlock |
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var ifInst = (IfInstruction)block.Instructions.SecondToLastOrDefault()!; |
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ifInst.Condition = new MatchInstruction(v, testedOperand) { |
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CheckNotNull = true, |
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CheckType = true |
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}.WithILRange(ifInst.Condition); |
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ifInst.TrueInst = trueInst; |
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block.Instructions[block.Instructions.Count - 1] = falseInst; |
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block.Instructions.RemoveRange(pos, ifInst.ChildIndex - pos); |
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v.Kind = VariableKind.PatternLocal; |
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if (trueInst.MatchBranch(out var trueBlock) && trueBlock.IncomingEdgeCount == 1 && trueBlock.Parent == container) |
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{ |
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DetectPropertySubPatterns((MatchInstruction)ifInst.Condition, trueBlock, falseInst, context); |
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} |
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return true; |
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} |
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private bool DetectPropertySubPatterns(MatchInstruction parentPattern, Block block, ILInstruction parentFalseInst, ILTransformContext context) |
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{ |
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// if (match.notnull.type[System.String] (V_0 = callvirt get_C(ldloc V_2))) br IL_0022 |
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// br IL_0037 |
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if (MatchBlockContainingOneCondition(block, out var condition, out var trueInst, out var falseInst)) |
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{ |
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if (MatchInstruction.IsPatternMatch(condition, out var operand)) |
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{ |
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if (operand is not CallInstruction { |
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Method: { |
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SymbolKind: SymbolKind.Accessor, |
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AccessorKind: MethodSemanticsAttributes.Getter |
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}, |
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Arguments: [LdLoc ldloc] |
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} call) |
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{ |
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return false; |
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} |
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if (ldloc.Variable != parentPattern.Variable) |
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{ |
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return false; |
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} |
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if (!DetectExitPoints.CompatibleExitInstruction(parentFalseInst, falseInst)) |
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{ |
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if (!DetectExitPoints.CompatibleExitInstruction(parentFalseInst, trueInst)) |
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{ |
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return false; |
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} |
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ExtensionMethods.Swap(ref trueInst, ref falseInst); |
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condition = Comp.LogicNot(condition); |
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} |
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context.Step("Move property sub pattern", condition); |
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parentPattern.SubPatterns.Add(condition); |
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block.Instructions.Clear(); |
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block.Instructions.Add(trueInst); |
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return true; |
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} |
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} |
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return false; |
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} |
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private static bool MatchBlockContainingOneCondition(Block block, [NotNullWhen(true)] out ILInstruction? condition, [NotNullWhen(true)] out ILInstruction? trueInst, [NotNullWhen(true)] out ILInstruction? falseInst) |
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{ |
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switch (block.Instructions.Count) |
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{ |
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case 2: |
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return block.MatchIfAtEndOfBlock(out condition, out trueInst, out falseInst); |
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case 3: |
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condition = null; |
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if (!block.MatchIfAtEndOfBlock(out var loadTemp, out trueInst, out falseInst)) |
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return false; |
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if (!(loadTemp.MatchLdLoc(out var tempVar) && tempVar.IsSingleDefinition && tempVar.LoadCount == 1)) |
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return false; |
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return block.Instructions[0].MatchStLoc(tempVar, out condition); |
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default: |
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condition = null; |
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trueInst = null; |
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falseInst = null; |
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return false; |
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} |
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} |
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private bool CheckAllUsesDominatedBy(ILVariable v, BlockContainer container, ILInstruction trueInst, |
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ILInstruction storeToV, ILInstruction? loadInNullCheck, ILTransformContext context, ref ControlFlowGraph? cfg) |
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{ |
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var targetBlock = trueInst as Block; |
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if (targetBlock == null && !trueInst.MatchBranch(out targetBlock)) |
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{ |
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return false; |
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} |
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if (targetBlock.Parent != container) |
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return false; |
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if (targetBlock.IncomingEdgeCount != 1) |
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return false; |
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cfg ??= new ControlFlowGraph(container, context.CancellationToken); |
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var targetBlockNode = cfg.GetNode(targetBlock); |
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var uses = v.LoadInstructions.Concat<ILInstruction>(v.AddressInstructions) |
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.Concat(v.StoreInstructions.Cast<ILInstruction>()); |
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foreach (var use in uses) |
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{ |
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if (use == storeToV || use == loadInNullCheck) |
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continue; |
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Block? found = null; |
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for (ILInstruction? current = use; current != null; current = current.Parent) |
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{ |
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if (current.Parent == container) |
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{ |
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found = (Block)current; |
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break; |
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} |
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} |
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if (found == null) |
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return false; |
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var node = cfg.GetNode(found); |
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if (!targetBlockNode.Dominates(node)) |
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return false; |
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} |
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return true; |
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} |
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/// Block { |
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/// ... |
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/// [stloc temp(ldloc testedOperand)] |
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/// if (comp.o(isinst T(ldloc testedOperand) == ldnull)) br falseBlock |
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/// br unboxBlock |
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/// } |
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/// |
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/// Block unboxBlock (incoming: 1) { |
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/// stloc V(unbox.any T(ldloc temp)) |
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/// ... |
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/// } |
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/// => |
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/// Block { |
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/// ... |
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/// if (match.type[T].notnull(V = testedOperand)) br unboxBlock |
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/// br falseBlock |
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/// } |
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private bool PatternMatchValueTypes(Block block, BlockContainer container, ILTransformContext context, ref ControlFlowGraph? cfg) |
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{ |
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if (!MatchIsInstBlock(block, out var type, out var testedOperand, out var testedVariable, |
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out var boxType1, out var unboxBlock, out var falseBlock)) |
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{ |
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return false; |
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} |
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StLoc? tempStore = block.Instructions.ElementAtOrDefault(block.Instructions.Count - 3) as StLoc; |
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if (tempStore == null || !tempStore.Value.MatchLdLoc(testedVariable)) |
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{ |
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tempStore = null; |
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} |
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if (!MatchUnboxBlock(unboxBlock, type, out var unboxOperand, out var boxType2, out var storeToV)) |
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{ |
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return false; |
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} |
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if (!object.Equals(boxType1, boxType2)) |
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{ |
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return false; |
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} |
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if (unboxOperand == testedVariable) |
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{ |
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// do nothing |
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} |
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else if (unboxOperand == tempStore?.Variable) |
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{ |
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if (!(tempStore.Variable.IsSingleDefinition && tempStore.Variable.LoadCount == 1)) |
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return false; |
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} |
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else |
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{ |
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return false; |
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} |
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if (!CheckAllUsesDominatedBy(storeToV.Variable, container, unboxBlock, storeToV, null, context, ref cfg)) |
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return false; |
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context.Step($"PatternMatching with {storeToV.Variable.Name}", block); |
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var ifInst = (IfInstruction)block.Instructions.SecondToLastOrDefault()!; |
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ifInst.Condition = new MatchInstruction(storeToV.Variable, testedOperand) { |
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CheckNotNull = true, |
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CheckType = true |
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}; |
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((Branch)ifInst.TrueInst).TargetBlock = unboxBlock; |
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((Branch)block.Instructions.Last()).TargetBlock = falseBlock; |
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unboxBlock.Instructions.RemoveAt(0); |
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if (unboxOperand == tempStore?.Variable) |
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{ |
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block.Instructions.Remove(tempStore); |
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} |
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// HACK: condition detection uses StartILOffset of blocks to decide which branch of if-else |
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// should become the then-branch. Change the unboxBlock StartILOffset from an offset inside |
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// the pattern matching machinery to an offset belonging to an instruction in the then-block. |
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unboxBlock.SetILRange(unboxBlock.Instructions[0]); |
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storeToV.Variable.Kind = VariableKind.PatternLocal; |
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return true; |
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} |
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/// ... |
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/// if (comp.o(isinst T(ldloc testedOperand) == ldnull)) br falseBlock |
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/// br unboxBlock |
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/// - or - |
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/// ... |
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/// if (comp.o(isinst T(box ``0(ldloc testedOperand)) == ldnull)) br falseBlock |
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/// br unboxBlock |
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private bool MatchIsInstBlock(Block block, |
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[NotNullWhen(true)] out IType? type, |
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[NotNullWhen(true)] out ILInstruction? testedOperand, |
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[NotNullWhen(true)] out ILVariable? testedVariable, |
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out IType? boxType, |
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[NotNullWhen(true)] out Block? unboxBlock, |
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[NotNullWhen(true)] out Block? falseBlock) |
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{ |
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type = null; |
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testedOperand = null; |
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testedVariable = null; |
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boxType = null; |
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unboxBlock = null; |
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falseBlock = null; |
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if (!block.MatchIfAtEndOfBlock(out var condition, out var trueInst, out var falseInst)) |
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{ |
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return false; |
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} |
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if (condition.MatchCompEqualsNull(out var arg)) |
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{ |
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ExtensionMethods.Swap(ref trueInst, ref falseInst); |
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} |
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else if (condition.MatchCompNotEqualsNull(out arg)) |
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{ |
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// do nothing |
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} |
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else |
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{ |
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return false; |
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} |
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if (!arg.MatchIsInst(out testedOperand, out type)) |
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{ |
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return false; |
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} |
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if (!(testedOperand.MatchBox(out var boxArg, out boxType) && boxType.Kind == TypeKind.TypeParameter)) |
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{ |
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boxArg = testedOperand; |
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} |
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if (!boxArg.MatchLdLoc(out testedVariable)) |
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{ |
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return false; |
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} |
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return trueInst.MatchBranch(out unboxBlock) && falseInst.MatchBranch(out falseBlock) |
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&& unboxBlock.Parent == block.Parent && falseBlock.Parent == block.Parent; |
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} |
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/// Block unboxBlock (incoming: 1) { |
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/// stloc V(unbox.any T(ldloc testedOperand)) |
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/// ... |
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/// - or - |
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/// stloc V(unbox.any T(isinst T(box ``0(ldloc testedOperand)))) |
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/// ... |
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/// } |
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private bool MatchUnboxBlock(Block unboxBlock, IType type, [NotNullWhen(true)] out ILVariable? testedVariable, |
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out IType? boxType, [NotNullWhen(true)] out StLoc? storeToV) |
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{ |
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boxType = null; |
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storeToV = null; |
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testedVariable = null; |
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if (unboxBlock.IncomingEdgeCount != 1) |
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return false; |
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storeToV = unboxBlock.Instructions[0] as StLoc; |
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if (storeToV == null) |
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return false; |
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var value = storeToV.Value; |
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if (!(value.MatchUnboxAny(out var arg, out var t) && t.Equals(type))) |
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return false; |
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if (arg.MatchIsInst(out var isinstArg, out var isinstType) && isinstType.Equals(type)) |
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{ |
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arg = isinstArg; |
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} |
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if (arg.MatchBox(out var boxArg, out boxType) && boxType.Kind == TypeKind.TypeParameter) |
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{ |
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arg = boxArg; |
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} |
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if (!arg.MatchLdLoc(out testedVariable)) |
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{ |
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return false; |
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} |
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if (boxType != null && !boxType.Equals(testedVariable.Type)) |
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{ |
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return false; |
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} |
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return true; |
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} |
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} |
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}
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