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564 lines
25 KiB
564 lines
25 KiB
// Copyright (c) 2017 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.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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/// <summary>
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/// Detects switch-on-string patterns employed by the C# compiler and transforms them to an ILAst-switch-instruction.
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/// </summary>
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class SwitchOnStringTransform : IILTransform
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{
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public void Run(ILFunction function, ILTransformContext context)
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{
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if (!context.Settings.SwitchStatementOnString)
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return;
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HashSet<BlockContainer> changedContainers = new HashSet<BlockContainer>();
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foreach (var block in function.Descendants.OfType<Block>()) {
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bool changed = false;
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for (int i = block.Instructions.Count - 1; i >= 0; i--) {
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SwitchInstruction newSwitch;
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if (SimplifyCascadingIfStatements(block.Instructions, i, out newSwitch, out var extraLoad, out var keepAssignmentBefore)) {
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if (extraLoad) {
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block.Instructions[i - 2].ReplaceWith(newSwitch);
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block.Instructions.RemoveRange(i - 1, 3);
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i -= 2;
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} else {
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if (keepAssignmentBefore) {
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block.Instructions[i].ReplaceWith(newSwitch);
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block.Instructions.RemoveAt(i + 1);
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} else {
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block.Instructions[i - 1].ReplaceWith(newSwitch);
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block.Instructions.RemoveRange(i, 2);
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i--;
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}
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}
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changed = true;
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continue;
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}
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if (MatchLegacySwitchOnStringWithHashtable(block.Instructions, i, out newSwitch)) {
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block.Instructions[i + 1].ReplaceWith(newSwitch);
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block.Instructions.RemoveAt(i);
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changed = true;
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continue;
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}
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if (MatchLegacySwitchOnStringWithDict(block.Instructions, i, out newSwitch, out keepAssignmentBefore)) {
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block.Instructions[i + 1].ReplaceWith(newSwitch);
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if (keepAssignmentBefore) {
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block.Instructions.RemoveAt(i);
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i--;
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} else {
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block.Instructions.RemoveRange(i - 1, 2);
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i -= 2;
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}
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changed = true;
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continue;
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}
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if (MatchRoslynSwitchOnString(block.Instructions, i, out newSwitch, out keepAssignmentBefore)) {
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block.Instructions[i].ReplaceWith(newSwitch);
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if (keepAssignmentBefore) {
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block.Instructions.RemoveAt(i - 1);
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i--;
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} else {
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block.Instructions.RemoveRange(i - 2, 2);
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i -= 2;
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}
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changed = true;
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continue;
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}
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}
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if (!changed) continue;
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SwitchDetection.SimplifySwitchInstruction(block);
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if (block.Parent is BlockContainer container)
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changedContainers.Add(container);
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}
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foreach (var container in changedContainers)
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container.SortBlocks(deleteUnreachableBlocks: true);
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}
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bool SimplifyCascadingIfStatements(InstructionCollection<ILInstruction> instructions, int i, out SwitchInstruction inst, out bool extraLoad, out bool keepAssignmentBefore)
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{
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inst = null;
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extraLoad = false;
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keepAssignmentBefore = false;
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if (i < 1) return false;
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// match first block: checking switch-value for null or first value (Roslyn)
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// if (call op_Equality(ldloc switchValueVar, ldstr value)) br firstBlock
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// -or-
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// if (comp(ldloc switchValueVar == ldnull)) br defaultBlock
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if (!(instructions[i].MatchIfInstruction(out var condition, out var firstBlockJump)))
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return false;
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if (!firstBlockJump.MatchBranch(out var firstBlock))
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return false;
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List<(string, Block)> values = new List<(string, Block)>();
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ILInstruction switchValue = null;
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// Roslyn: match call to operator ==(string, string)
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if (MatchStringEqualityComparison(condition, out var switchValueVar, out string value)) {
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values.Add((value, firstBlock));
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if(!instructions[i - 1].MatchStLoc(switchValueVar, out switchValue)) {
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switchValue = new LdLoc(switchValueVar);
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}
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} else {
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// match null check with different variable:
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// this is used by the old C# compiler.
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if (MatchCompEqualsNull(condition, out var otherSwitchValueVar)) {
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values.Add((null, firstBlock));
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} else {
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return false;
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}
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// in case of optimized legacy code there are two stlocs:
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// stloc otherSwitchValueVar(ldloc switchValue)
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// stloc switchValueVar(ldloc otherSwitchValueVar)
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// if (comp(ldloc otherSwitchValueVar == ldnull)) br nullCase
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if (i > 1 && otherSwitchValueVar != null && instructions[i - 2].MatchStLoc(otherSwitchValueVar, out switchValue)
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&& instructions[i - 1].MatchStLoc(out switchValueVar, out var switchValueCopyInst)
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&& switchValueCopyInst.MatchLdLoc(otherSwitchValueVar) && otherSwitchValueVar.IsSingleDefinition && otherSwitchValueVar.LoadCount == 2) {
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extraLoad = true;
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} else if (instructions[i - 1].MatchStLoc(out switchValueVar, out switchValue)) {
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// unoptimized legacy switch
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}
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}
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// if instruction must be followed by a branch to the next case
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if (!(instructions.ElementAtOrDefault(i + 1) is Branch nextCaseJump))
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return false;
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// extract all cases and add them to the values list.
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Block currentCaseBlock = nextCaseJump.TargetBlock;
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Block nextCaseBlock;
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while ((nextCaseBlock = MatchCaseBlock(currentCaseBlock, switchValueVar, out value, out Block block)) != null) {
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values.Add((value, block));
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currentCaseBlock = nextCaseBlock;
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}
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// We didn't find enough cases, exit
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if (values.Count < 3)
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return false;
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// if the switchValueVar is used in other places as well, do not eliminate the store.
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if (switchValueVar.LoadCount > values.Count) {
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keepAssignmentBefore = true;
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switchValue = new LdLoc(switchValueVar);
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}
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var sections = new List<SwitchSection>(values.SelectWithIndex((index, b) => new SwitchSection { Labels = new LongSet(index), Body = new Branch(b.Item2) }));
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sections.Add(new SwitchSection { Labels = new LongSet(new LongInterval(0, sections.Count)).Invert(), Body = new Branch(currentCaseBlock) });
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var stringToInt = new StringToInt(switchValue, values.SelectArray(item => item.Item1));
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inst = new SwitchInstruction(stringToInt);
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inst.Sections.AddRange(sections);
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return true;
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}
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/// <summary>
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/// Each case consists of two blocks:
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/// 1. block:
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/// if (call op_Equality(ldloc switchVariable, ldstr value)) br caseBlock
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/// br nextBlock
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/// -or-
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/// if (comp(ldloc switchValueVar == ldnull)) br nextBlock
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/// br caseBlock
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/// 2. block is caseBlock
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/// This method matches the above pattern or its inverted form:
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/// the call to ==(string, string) is wrapped in logic.not and the branch targets are reversed.
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/// Returns the next block that follows in the block-chain.
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/// The <paramref name="switchVariable"/> is updated if the value gets copied to a different variable.
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/// See comments below for more info.
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/// </summary>
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Block MatchCaseBlock(Block currentBlock, ILVariable switchVariable, out string value, out Block caseBlock)
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{
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value = null;
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caseBlock = null;
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if (currentBlock.IncomingEdgeCount != 1 || currentBlock.Instructions.Count != 2)
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return null;
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if (!currentBlock.Instructions[0].MatchIfInstruction(out var condition, out var caseBlockBranch))
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return null;
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if (!caseBlockBranch.MatchBranch(out caseBlock))
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return null;
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Block nextBlock;
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if (condition.MatchLogicNot(out var inner)) {
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condition = inner;
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nextBlock = caseBlock;
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if (!currentBlock.Instructions[1].MatchBranch(out caseBlock))
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return null;
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} else {
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if (!currentBlock.Instructions[1].MatchBranch(out nextBlock))
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return null;
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}
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if (!MatchStringEqualityComparison(condition, out var v, out value)) {
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if (MatchCompEqualsNull(condition, out v)) {
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value = null;
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} else {
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return null;
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}
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}
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if (v != switchVariable)
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return null;
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return nextBlock;
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}
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/// <summary>
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/// Returns true if <paramref name="left"/> is only assigned once and the initialization is done by copying <paramref name="right"/>.
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/// </summary>
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bool IsInitializedBy(ILVariable left, ILVariable right)
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{
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if (!left.IsSingleDefinition)
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return false;
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var storeInst = left.StoreInstructions.OfType<StLoc>().SingleOrDefault();
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if (storeInst == null)
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return false;
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return storeInst.Value.MatchLdLoc(right);
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}
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/// <summary>
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/// Matches the C# 2.0 switch-on-string pattern, which uses Dictionary<string, int>.
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/// </summary>
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bool MatchLegacySwitchOnStringWithDict(InstructionCollection<ILInstruction> instructions, int i, out SwitchInstruction inst, out bool keepAssignmentBefore)
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{
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inst = null;
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keepAssignmentBefore = false;
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if (i < 1) return false;
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// match first block: checking switch-value for null
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if (!(instructions[i].MatchIfInstruction(out var condition, out var exitBlockJump) &&
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instructions[i - 1].MatchStLoc(out var switchValueVar, out var switchValue) && switchValueVar.Type.IsKnownType(KnownTypeCode.String)))
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return false;
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if (!switchValueVar.IsSingleDefinition)
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return false;
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if (!exitBlockJump.MatchBranch(out var nullValueCaseBlock))
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return false;
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if (!(condition.MatchCompEquals(out var left, out var right) && right.MatchLdNull() && (left.Match(switchValue).Success || left.MatchLdLoc(switchValueVar))))
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return false;
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var nextBlockJump = instructions.ElementAtOrDefault(i + 1) as Branch;
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if (nextBlockJump == null || nextBlockJump.TargetBlock.IncomingEdgeCount != 1)
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return false;
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// match second block: checking compiler-generated Dictionary<string, int> for null
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var nextBlock = nextBlockJump.TargetBlock;
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if (nextBlock.Instructions.Count != 2 || !nextBlock.Instructions[0].MatchIfInstruction(out condition, out var tryGetValueBlockJump))
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return false;
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if (!tryGetValueBlockJump.MatchBranch(out var tryGetValueBlock))
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return false;
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if (!nextBlock.Instructions[1].MatchBranch(out var dictInitBlock) || dictInitBlock.IncomingEdgeCount != 1)
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return false;
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if (!(condition.MatchCompNotEquals(out left, out right) && right.MatchLdNull() &&
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MatchDictionaryFieldLoad(left, IsStringToIntDictionary, out var dictField, out var dictionaryType)))
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return false;
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// match third block: initialization of compiler-generated Dictionary<string, int>
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if (dictInitBlock.IncomingEdgeCount != 1 || dictInitBlock.Instructions.Count < 3)
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return false;
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if (!ExtractStringValuesFromInitBlock(dictInitBlock, out var stringValues, tryGetValueBlock, dictionaryType, dictField))
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return false;
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// match fourth block: TryGetValue on compiler-generated Dictionary<string, int>
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if (tryGetValueBlock.IncomingEdgeCount != 2 || tryGetValueBlock.Instructions.Count != 2)
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return false;
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if (!tryGetValueBlock.Instructions[0].MatchIfInstruction(out condition, out var defaultBlockJump))
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return false;
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if (!defaultBlockJump.MatchBranch(out var defaultBlock))
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return false;
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if (!(condition.MatchLogicNot(out var arg) && arg is Call c && c.Method.Name == "TryGetValue" &&
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MatchDictionaryFieldLoad(c.Arguments[0], IsStringToIntDictionary, out var dictField2, out _) && dictField2.Equals(dictField)))
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return false;
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if (!c.Arguments[1].MatchLdLoc(switchValueVar) || !c.Arguments[2].MatchLdLoca(out var switchIndexVar))
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return false;
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if (!tryGetValueBlock.Instructions[1].MatchBranch(out var switchBlock))
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return false;
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// match fifth block: switch-instruction block
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if (switchBlock.IncomingEdgeCount != 1 || switchBlock.Instructions.Count != 1)
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return false;
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if (!(switchBlock.Instructions[0] is SwitchInstruction switchInst && switchInst.Value.MatchLdLoc(switchIndexVar)))
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return false;
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var sections = new List<SwitchSection>(switchInst.Sections);
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// switch contains case null:
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if (nullValueCaseBlock != defaultBlock) {
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var label = new Util.LongSet(switchInst.Sections.Count);
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var possibleConflicts = switchInst.Sections.Where(sec => sec.Labels.Overlaps(label)).ToArray();
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if (possibleConflicts.Length > 1)
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return false;
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else if (possibleConflicts.Length == 1)
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possibleConflicts[0].Labels = possibleConflicts[0].Labels.ExceptWith(label);
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stringValues.Add(null);
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sections.Add(new SwitchSection() { Labels = label, Body = new Branch(nullValueCaseBlock) });
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}
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if (switchValueVar.LoadCount > 2) {
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switchValue = new LdLoc(switchValueVar);
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keepAssignmentBefore = true;
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}
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var stringToInt = new StringToInt(switchValue, stringValues.ToArray());
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inst = new SwitchInstruction(stringToInt);
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inst.Sections.AddRange(sections);
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return true;
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}
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bool MatchDictionaryFieldLoad(ILInstruction inst, Func<IType, bool> typeMatcher, out IField dictField, out IType dictionaryType)
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{
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dictField = null;
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dictionaryType = null;
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return inst.MatchLdObj(out var dictionaryFieldLoad, out dictionaryType) &&
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typeMatcher(dictionaryType) &&
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dictionaryFieldLoad.MatchLdsFlda(out dictField) &&
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(dictField.IsCompilerGeneratedOrIsInCompilerGeneratedClass() || dictField.Name.StartsWith("$$method", StringComparison.Ordinal));
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}
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bool ExtractStringValuesFromInitBlock(Block block, out List<string> values, Block targetBlock, IType dictionaryType, IField dictionaryField)
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{
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values = null;
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if (!(block.Instructions[0].MatchStLoc(out var dictVar, out var newObjDict) &&
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newObjDict is NewObj newObj && newObj.Arguments.Count >= 1 && newObj.Arguments[0].MatchLdcI4(out var valuesLength)))
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return false;
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values = new List<string>(valuesLength);
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int i = 0;
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while (i + 1 < block.Instructions.Count - 2 && MatchAddCall(block.Instructions[i + 1], dictVar, i, out var value)) {
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values.Add(value);
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i++;
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}
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if (!(block.Instructions[i + 1].MatchStObj(out var loadField, out var dictVarLoad, out var dictType) &&
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dictType.Equals(dictionaryType) && loadField.MatchLdsFlda(out var dictField) && dictField.Equals(dictionaryField)) &&
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dictVarLoad.MatchLdLoc(dictVar))
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return false;
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return block.Instructions[i + 2].MatchBranch(targetBlock);
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}
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bool MatchAddCall(ILInstruction inst, ILVariable dictVar, int i, out string value)
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{
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value = null;
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return inst is Call c && c.Method.Name == "Add" && c.Arguments.Count == 3 &&
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c.Arguments[0].MatchLdLoc(dictVar) && c.Arguments[1].MatchLdStr(out value) &&
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(c.Arguments[2].MatchLdcI4(i) || (c.Arguments[2].MatchBox(out var arg, out _) && arg.MatchLdcI4(i)));
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}
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bool IsStringToIntDictionary(IType dictionaryType)
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{
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if (dictionaryType.FullName != "System.Collections.Generic.Dictionary")
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return false;
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if (dictionaryType.TypeArguments.Count != 2)
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return false;
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return dictionaryType.TypeArguments[0].IsKnownType(KnownTypeCode.String) &&
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dictionaryType.TypeArguments[1].IsKnownType(KnownTypeCode.Int32);
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}
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bool IsNonGenericHashtable(IType dictionaryType)
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{
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if (dictionaryType.FullName != "System.Collections.Hashtable")
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return false;
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if (dictionaryType.TypeArguments.Count != 0)
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return false;
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return true;
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}
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bool MatchLegacySwitchOnStringWithHashtable(InstructionCollection<ILInstruction> instructions, int i, out SwitchInstruction inst)
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{
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inst = null;
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// match first block: checking compiler-generated Hashtable for null
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// if (comp(volatile.ldobj System.Collections.Hashtable(ldsflda $$method0x600003f-1) != ldnull)) br switchHeadBlock
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// br tableInitBlock
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if (!(instructions[i].MatchIfInstruction(out var condition, out var branchToSwitchHead) && i + 1 < instructions.Count))
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return false;
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if (!instructions[i + 1].MatchBranch(out var tableInitBlock) || tableInitBlock.IncomingEdgeCount != 1)
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return false;
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if (!(condition.MatchCompNotEquals(out var left, out var right) && right.MatchLdNull() &&
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MatchDictionaryFieldLoad(left, IsNonGenericHashtable, out var dictField, out var dictionaryType)))
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return false;
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if (!branchToSwitchHead.MatchBranch(out var switchHead))
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return false;
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// match second block: initialization of compiler-generated Hashtable
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// stloc table(newobj Hashtable..ctor(ldc.i4 capacity, ldc.f loadFactor))
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// call Add(ldloc table, ldstr value, box System.Int32(ldc.i4 index))
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// ... more calls to Add ...
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// volatile.stobj System.Collections.Hashtable(ldsflda $$method0x600003f - 1, ldloc table)
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// br switchHeadBlock
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if (tableInitBlock.IncomingEdgeCount != 1 || tableInitBlock.Instructions.Count < 3)
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return false;
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if (!ExtractStringValuesFromInitBlock(tableInitBlock, out var stringValues, switchHead, dictionaryType, dictField))
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return false;
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// match third block: checking switch-value for null
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// stloc tmp(ldloc switch-value)
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// stloc switchVariable(ldloc tmp)
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// if (comp(ldloc tmp == ldnull)) br nullCaseBlock
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// br getItemBlock
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if (switchHead.Instructions.Count != 4 || switchHead.IncomingEdgeCount != 2)
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return false;
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if (!switchHead.Instructions[0].MatchStLoc(out var tmp, out var switchValue))
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return false;
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if (!switchHead.Instructions[1].MatchStLoc(out var switchVariable, out var tmpLoad) || !tmpLoad.MatchLdLoc(tmp))
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return false;
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if (!switchHead.Instructions[2].MatchIfInstruction(out condition, out var nullCaseBlockBranch))
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return false;
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if (!switchHead.Instructions[3].MatchBranch(out var getItemBlock) || !nullCaseBlockBranch.MatchBranch(out var nullCaseBlock))
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return false;
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if (!(condition.MatchCompEquals(out left, out right) && right.MatchLdNull() && left.MatchLdLoc(tmp)))
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return false;
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// match fourth block: get_Item on compiler-generated Hashtable
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// stloc tmp2(call get_Item(volatile.ldobj System.Collections.Hashtable(ldsflda $$method0x600003f - 1), ldloc switchVariable))
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// stloc switchVariable(ldloc tmp2)
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// if (comp(ldloc tmp2 == ldnull)) br defaultCaseBlock
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// br switchBlock
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if (getItemBlock.IncomingEdgeCount != 1 || getItemBlock.Instructions.Count != 4)
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return false;
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if (!(getItemBlock.Instructions[0].MatchStLoc(out var tmp2, out var getItem) && getItem is Call getItemCall && getItemCall.Method.Name == "get_Item"))
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return false;
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if (!getItemBlock.Instructions[1].MatchStLoc(out var switchVariable2, out var tmp2Load) || !tmp2Load.MatchLdLoc(tmp2))
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return false;
|
|
if (!ILVariableEqualityComparer.Instance.Equals(switchVariable, switchVariable2))
|
|
return false;
|
|
if (!getItemBlock.Instructions[2].MatchIfInstruction(out condition, out var defaultBlockBranch))
|
|
return false;
|
|
if (!getItemBlock.Instructions[3].MatchBranch(out var switchBlock) || !defaultBlockBranch.MatchBranch(out var defaultBlock))
|
|
return false;
|
|
if (!(condition.MatchCompEquals(out left, out right) && right.MatchLdNull() && left.MatchLdLoc(tmp2)))
|
|
return false;
|
|
if (!(getItemCall.Arguments.Count == 2 && MatchDictionaryFieldLoad(getItemCall.Arguments[0], IsStringToIntDictionary, out var dictField2, out _) && dictField2.Equals(dictField)) &&
|
|
getItemCall.Arguments[1].MatchLdLoc(switchVariable2))
|
|
return false;
|
|
// match fifth block: switch-instruction block
|
|
// switch (ldobj System.Int32(unbox System.Int32(ldloc switchVariable))) {
|
|
// case [0..1): br caseBlock1
|
|
// ... more cases ...
|
|
// case [long.MinValue..0),[13..long.MaxValue]: br defaultBlock
|
|
// }
|
|
if (switchBlock.IncomingEdgeCount != 1 || switchBlock.Instructions.Count != 1)
|
|
return false;
|
|
if (!(switchBlock.Instructions[0] is SwitchInstruction switchInst && switchInst.Value.MatchLdObj(out var target, out var ldobjType) &&
|
|
target.MatchUnbox(out var arg, out var unboxType) && arg.MatchLdLoc(switchVariable2) && ldobjType.IsKnownType(KnownTypeCode.Int32) && unboxType.Equals(ldobjType)))
|
|
return false;
|
|
var sections = new List<SwitchSection>(switchInst.Sections);
|
|
// switch contains case null:
|
|
if (nullCaseBlock != defaultBlock) {
|
|
var label = new Util.LongSet(switchInst.Sections.Count);
|
|
var possibleConflicts = switchInst.Sections.Where(sec => sec.Labels.Overlaps(label)).ToArray();
|
|
if (possibleConflicts.Length > 1)
|
|
return false;
|
|
else if (possibleConflicts.Length == 1)
|
|
possibleConflicts[0].Labels = possibleConflicts[0].Labels.ExceptWith(label);
|
|
stringValues.Add(null);
|
|
sections.Add(new SwitchSection() { Labels = label, Body = new Branch(nullCaseBlock) });
|
|
}
|
|
var stringToInt = new StringToInt(switchValue, stringValues.ToArray());
|
|
inst = new SwitchInstruction(stringToInt);
|
|
inst.Sections.AddRange(sections);
|
|
return true;
|
|
}
|
|
|
|
bool MatchRoslynSwitchOnString(InstructionCollection<ILInstruction> instructions, int i, out SwitchInstruction inst, out bool keepAssignmentBefore)
|
|
{
|
|
inst = null;
|
|
keepAssignmentBefore = false;
|
|
if (i < 1) return false;
|
|
if (!(instructions[i] is SwitchInstruction switchInst && switchInst.Value.MatchLdLoc(out var targetVar) &&
|
|
MatchComputeStringHashCall(instructions[i - 1], targetVar, out var switchValue)))
|
|
return false;
|
|
|
|
var stringValues = new List<(int, string, Block)>();
|
|
int index = 0;
|
|
ILInstruction defaultBranch = null;
|
|
foreach (var section in switchInst.Sections) {
|
|
if (!section.Body.MatchBranch(out Block target)) {
|
|
if (section.Body is Leave leave) {
|
|
defaultBranch = leave;
|
|
continue;
|
|
}
|
|
return false;
|
|
}
|
|
if (target.IncomingEdgeCount > 1) {
|
|
defaultBranch = new Branch(target);
|
|
continue;
|
|
}
|
|
if (target.Instructions.Count != 2)
|
|
return false;
|
|
if (!target.Instructions[0].MatchIfInstruction(out var condition, out var bodyBranch))
|
|
return false;
|
|
if (!bodyBranch.MatchBranch(out Block body))
|
|
return false;
|
|
if (!MatchStringEqualityOrNullComparison(condition, switchValue.Variable, out string stringValue)) {
|
|
if (condition.MatchLogicNot(out condition) && MatchStringEqualityOrNullComparison(condition, switchValue.Variable, out stringValue)) {
|
|
if (!target.Instructions[1].MatchBranch(out Block exit))
|
|
return false;
|
|
body = exit;
|
|
} else
|
|
return false;
|
|
}
|
|
stringValues.Add((index++, stringValue, body));
|
|
}
|
|
ILInstruction switchValueInst = switchValue;
|
|
if (i > 1 && instructions[i - 2].MatchStLoc(switchValue.Variable, out var switchValueTmp) &&
|
|
switchValue.Variable.IsSingleDefinition && switchValue.Variable.LoadCount == switchInst.Sections.Count) {
|
|
switchValueInst = switchValueTmp;
|
|
} else {
|
|
keepAssignmentBefore = true;
|
|
}
|
|
var defaultLabel = new LongSet(new LongInterval(0, index)).Invert();
|
|
var value = new StringToInt(switchValueInst, stringValues.Select(item => item.Item2).ToArray());
|
|
inst = new SwitchInstruction(value);
|
|
inst.Sections.AddRange(stringValues.Select(section => new SwitchSection { Labels = new Util.LongSet(section.Item1), Body = new Branch(section.Item3) }));
|
|
inst.Sections.Add(new SwitchSection { Labels = defaultLabel, Body = defaultBranch });
|
|
return true;
|
|
}
|
|
|
|
bool MatchComputeStringHashCall(ILInstruction inst, ILVariable targetVar, out LdLoc switchValue)
|
|
{
|
|
switchValue = null;
|
|
if (!inst.MatchStLoc(targetVar, out var value))
|
|
return false;
|
|
if (!(value is Call c && c.Arguments.Count == 1 && c.Method.Name == "ComputeStringHash" && c.Method.IsCompilerGeneratedOrIsInCompilerGeneratedClass()))
|
|
return false;
|
|
if (!(c.Arguments[0] is LdLoc))
|
|
return false;
|
|
switchValue = (LdLoc)c.Arguments[0];
|
|
return true;
|
|
}
|
|
|
|
bool MatchStringEqualityOrNullComparison(ILInstruction condition, ILVariable variable, out string stringValue)
|
|
{
|
|
if (!MatchStringEqualityComparison(condition, out var v, out stringValue)) {
|
|
if (!MatchCompEqualsNull(condition, out v))
|
|
return false;
|
|
stringValue = null;
|
|
}
|
|
|
|
return v == variable;
|
|
}
|
|
|
|
bool MatchStringEqualityComparison(ILInstruction condition, out ILVariable variable, out string stringValue)
|
|
{
|
|
stringValue = null;
|
|
variable = null;
|
|
ILInstruction left, right;
|
|
if (condition is Call c && c.Method.IsOperator && c.Method.Name == "op_Equality" && c.Arguments.Count == 2) {
|
|
left = c.Arguments[0];
|
|
right = c.Arguments[1];
|
|
if (!right.MatchLdStr(out stringValue))
|
|
return false;
|
|
} else {
|
|
return false;
|
|
}
|
|
return left.MatchLdLoc(out variable);
|
|
}
|
|
|
|
bool MatchCompEqualsNull(ILInstruction condition, out ILVariable variable)
|
|
{
|
|
variable = null;
|
|
if (!condition.MatchCompEquals(out var left, out var right))
|
|
return false;
|
|
return right.MatchLdNull() && left.MatchLdLoc(out variable);
|
|
}
|
|
}
|
|
}
|