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1023 lines
40 KiB
1023 lines
40 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.Diagnostics; |
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using System.Linq; |
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using System.Linq.Expressions; |
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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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/// Constructs compound assignments and inline assignments. |
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/// </summary> |
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/// <remarks> |
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/// This is a statement transform; |
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/// but some portions are executed as an expression transform instead |
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/// (with HandleCompoundAssign() as entry point) |
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/// </remarks> |
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public class TransformAssignment : IStatementTransform |
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{ |
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StatementTransformContext context; |
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void IStatementTransform.Run(Block block, int pos, StatementTransformContext context) |
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{ |
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this.context = context; |
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if (context.Settings.MakeAssignmentExpressions) |
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{ |
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if (TransformInlineAssignmentStObjOrCall(block, pos) || TransformInlineAssignmentLocal(block, pos)) |
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{ |
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// both inline assignments create a top-level stloc which might affect inlining |
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context.RequestRerun(); |
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return; |
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} |
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} |
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if (context.Settings.IntroduceIncrementAndDecrement) |
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{ |
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if (TransformPostIncDecOperatorWithInlineStore(block, pos) |
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|| TransformPostIncDecOperator(block, pos)) |
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{ |
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// again, new top-level stloc might need inlining: |
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context.RequestRerun(); |
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return; |
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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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/// where ... is pure and does not use s or l, |
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/// and where neither the 'stloc s' nor the 'stobj' truncates |
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/// --> |
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/// stloc l(stobj (..., value)) |
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/// </code> |
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/// e.g. used for inline assignment to instance field |
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/// |
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/// -or- |
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/// |
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/// <code> |
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/// stloc s(value) |
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/// stobj (..., ldloc s) |
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/// where ... is pure and does not use s, and where the 'stobj' does not truncate |
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/// --> |
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/// stloc s(stobj (..., value)) |
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/// </code> |
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/// e.g. used for inline assignment to static field |
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/// |
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/// -or- |
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/// |
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/// <code> |
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/// stloc s(value) |
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/// call set_Property(..., ldloc s) |
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/// where the '...' arguments are pure and not using 's' |
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/// --> |
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/// stloc s(Block InlineAssign { call set_Property(..., stloc i(value)); final: ldloc i }) |
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/// new temporary 'i' has type of the property; transform only valid if 'stloc i' doesn't truncate |
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/// </code> |
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bool TransformInlineAssignmentStObjOrCall(Block block, int pos) |
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{ |
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var inst = block.Instructions[pos] 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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if (IsImplicitTruncation(inst.Value, inst.Variable.Type, context.TypeSystem)) |
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{ |
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// 'stloc s' is implicitly truncating the value |
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return false; |
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} |
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ILVariable local; |
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int nextPos; |
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if (block.Instructions[pos + 1] is StLoc localStore) |
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{ // with extra local |
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if (localStore.Variable.Kind != VariableKind.Local || !localStore.Value.MatchLdLoc(inst.Variable)) |
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return false; |
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// if we're using an extra local, we'll delete "s", so check that that doesn't have any additional uses |
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if (!(inst.Variable.IsSingleDefinition && inst.Variable.LoadCount == 2)) |
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return false; |
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local = localStore.Variable; |
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nextPos = pos + 2; |
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} |
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else |
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{ |
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local = inst.Variable; |
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localStore = null; |
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nextPos = pos + 1; |
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if (local.LoadCount == 1 && local.AddressCount == 0) |
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{ |
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// inline assignment would produce a dead store in this case, which is ugly |
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// and causes problems with the deconstruction transform. |
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return false; |
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} |
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} |
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if (block.Instructions[nextPos] is StObj stobj) |
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{ |
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if (!stobj.Value.MatchLdLoc(inst.Variable)) |
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return false; |
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if (!SemanticHelper.IsPure(stobj.Target.Flags) || inst.Variable.IsUsedWithin(stobj.Target)) |
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return false; |
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var pointerType = stobj.Target.InferType(context.TypeSystem); |
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IType newType = stobj.Type; |
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if (TypeUtils.IsCompatiblePointerTypeForMemoryAccess(pointerType, stobj.Type)) |
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{ |
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if (pointerType is ByReferenceType byref) |
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newType = byref.ElementType; |
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else if (pointerType is PointerType pointer) |
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newType = pointer.ElementType; |
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} |
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var truncation = CheckImplicitTruncation(inst.Value, newType, context.TypeSystem); |
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if (truncation == ImplicitTruncationResult.ValueChanged) |
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{ |
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// 'stobj' is implicitly truncating the value |
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return false; |
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} |
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if (truncation == ImplicitTruncationResult.ValueChangedDueToSignMismatch) |
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{ |
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// Change the sign of the type to skip implicit truncation |
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newType = SwapSign(newType, context.TypeSystem); |
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} |
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context.Step("Inline assignment stobj", stobj); |
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stobj.Type = newType; |
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block.Instructions.Remove(localStore); |
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block.Instructions.Remove(stobj); |
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stobj.Value = inst.Value; |
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inst.ReplaceWith(new StLoc(local, stobj)); |
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// note: our caller will trigger a re-run, which will call HandleStObjCompoundAssign if applicable |
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return true; |
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} |
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else if (block.Instructions[nextPos] is CallInstruction call) |
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{ |
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// call must be a setter call: |
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if (!(call.OpCode == OpCode.Call || call.OpCode == OpCode.CallVirt)) |
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return false; |
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if (call.ResultType != StackType.Void || call.Arguments.Count == 0) |
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return false; |
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IProperty property = call.Method.AccessorOwner as IProperty; |
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if (property == null) |
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return false; |
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if (!call.Method.Equals(property.Setter)) |
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return false; |
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if (!(property.IsIndexer || property.Setter.Parameters.Count == 1)) |
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{ |
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// this is a parameterized property, which cannot be expressed as C# code. |
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// setter calls are not valid in expression context, if property syntax cannot be used. |
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return false; |
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} |
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if (!call.Arguments.Last().MatchLdLoc(inst.Variable)) |
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return false; |
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foreach (var arg in call.Arguments.SkipLast(1)) |
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{ |
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if (!SemanticHelper.IsPure(arg.Flags) || inst.Variable.IsUsedWithin(arg)) |
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return false; |
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} |
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if (IsImplicitTruncation(inst.Value, call.Method.Parameters.Last().Type, context.TypeSystem)) |
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{ |
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// setter call is implicitly truncating the value |
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return false; |
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} |
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// stloc s(Block InlineAssign { call set_Property(..., stloc i(value)); final: ldloc i }) |
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context.Step("Inline assignment call", call); |
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block.Instructions.Remove(localStore); |
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block.Instructions.Remove(call); |
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var newVar = context.Function.RegisterVariable(VariableKind.StackSlot, call.Method.Parameters.Last().Type); |
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call.Arguments[call.Arguments.Count - 1] = new StLoc(newVar, inst.Value); |
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var inlineBlock = new Block(BlockKind.CallInlineAssign) { |
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Instructions = { call }, |
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FinalInstruction = new LdLoc(newVar) |
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}; |
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inst.ReplaceWith(new StLoc(local, inlineBlock)); |
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// because the ExpressionTransforms don't look into inline blocks, manually trigger HandleCallCompoundAssign |
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if (HandleCompoundAssign(call, context)) |
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{ |
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// if we did construct a compound assignment, it should have made our inline block redundant: |
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Debug.Assert(!inlineBlock.IsConnected); |
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} |
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return true; |
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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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} |
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private static IType SwapSign(IType type, ICompilation compilation) |
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{ |
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return type.ToPrimitiveType() switch { |
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PrimitiveType.I1 => compilation.FindType(KnownTypeCode.Byte), |
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PrimitiveType.I2 => compilation.FindType(KnownTypeCode.UInt16), |
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PrimitiveType.I4 => compilation.FindType(KnownTypeCode.UInt32), |
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PrimitiveType.I8 => compilation.FindType(KnownTypeCode.UInt64), |
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PrimitiveType.U1 => compilation.FindType(KnownTypeCode.SByte), |
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PrimitiveType.U2 => compilation.FindType(KnownTypeCode.Int16), |
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PrimitiveType.U4 => compilation.FindType(KnownTypeCode.Int32), |
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PrimitiveType.U8 => compilation.FindType(KnownTypeCode.Int64), |
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PrimitiveType.I => compilation.FindType(KnownTypeCode.UIntPtr), |
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PrimitiveType.U => compilation.FindType(KnownTypeCode.IntPtr), |
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_ => throw new ArgumentException("Type must have an opposing sign: " + type, nameof(type)) |
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}; |
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} |
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static ILInstruction UnwrapSmallIntegerConv(ILInstruction inst, out Conv conv) |
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{ |
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conv = inst as Conv; |
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if (conv != null && conv.Kind == ConversionKind.Truncate && conv.TargetType.IsSmallIntegerType()) |
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{ |
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// for compound assignments to small integers, the compiler emits a "conv" instruction |
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return conv.Argument; |
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} |
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else |
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{ |
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return inst; |
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} |
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} |
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static bool ValidateCompoundAssign(BinaryNumericInstruction binary, Conv conv, IType targetType, DecompilerSettings settings) |
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{ |
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if (!NumericCompoundAssign.IsBinaryCompatibleWithType(binary, targetType, settings)) |
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return false; |
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if (conv != null && !(conv.TargetType == targetType.ToPrimitiveType() && conv.CheckForOverflow == binary.CheckForOverflow)) |
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return false; // conv does not match binary operation |
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return true; |
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} |
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static bool MatchingGetterAndSetterCalls(CallInstruction getterCall, CallInstruction setterCall, out Action<ILTransformContext> finalizeMatch) |
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{ |
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finalizeMatch = null; |
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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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if (setterCall.OpCode != getterCall.OpCode) |
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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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if (setterCall.Arguments.Count != getterCall.Arguments.Count + 1) |
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return false; |
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// Ensure that same arguments are passed to getterCall and setterCall: |
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for (int j = 0; j < getterCall.Arguments.Count; j++) |
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{ |
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if (setterCall.Arguments[j].MatchStLoc(out var v) && v.IsSingleDefinition && v.LoadCount == 1) |
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{ |
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if (getterCall.Arguments[j].MatchLdLoc(v)) |
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{ |
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// OK, setter call argument is saved in temporary that is re-used for getter call |
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if (finalizeMatch == null) |
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{ |
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finalizeMatch = AdjustArguments; |
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} |
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continue; |
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} |
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} |
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if (!SemanticHelper.IsPure(getterCall.Arguments[j].Flags)) |
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return false; |
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if (!getterCall.Arguments[j].Match(setterCall.Arguments[j]).Success) |
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return false; |
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} |
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return true; |
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void AdjustArguments(ILTransformContext context) |
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{ |
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Debug.Assert(setterCall.Arguments.Count == getterCall.Arguments.Count + 1); |
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for (int j = 0; j < getterCall.Arguments.Count; j++) |
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{ |
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if (setterCall.Arguments[j].MatchStLoc(out var v, out var value)) |
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{ |
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Debug.Assert(v.IsSingleDefinition && v.LoadCount == 1); |
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Debug.Assert(getterCall.Arguments[j].MatchLdLoc(v)); |
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getterCall.Arguments[j] = value; |
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} |
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} |
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} |
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} |
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/// <summary> |
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/// Transform compound assignments where the return value is not being used, |
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/// or where there's an inlined assignment within the setter call. |
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/// |
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/// Patterns handled: |
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/// 1. |
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/// callvirt set_Property(ldloc S_1, binary.op(callvirt get_Property(ldloc S_1), value)) |
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/// ==> compound.op.new(callvirt get_Property(ldloc S_1), value) |
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/// 2. |
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/// callvirt set_Property(ldloc S_1, stloc v(binary.op(callvirt get_Property(ldloc S_1), value))) |
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/// ==> stloc v(compound.op.new(callvirt get_Property(ldloc S_1), value)) |
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/// 3. |
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/// stobj(target, binary.op(ldobj(target), ...)) |
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/// where target is pure |
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/// => compound.op(target, ...) |
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/// </summary> |
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/// <remarks> |
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/// Called by ExpressionTransforms, or after the inline-assignment transform for setters. |
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/// </remarks> |
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internal static bool HandleCompoundAssign(ILInstruction compoundStore, StatementTransformContext context) |
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{ |
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if (!context.Settings.MakeAssignmentExpressions || !context.Settings.IntroduceIncrementAndDecrement) |
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return false; |
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if (compoundStore is CallInstruction && compoundStore.SlotInfo != Block.InstructionSlot) |
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{ |
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// replacing 'call set_Property' with a compound assignment instruction |
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// changes the return value of the expression, so this is only valid on block-level. |
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return false; |
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} |
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if (!IsCompoundStore(compoundStore, out var targetType, out var setterValue, context.TypeSystem)) |
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return false; |
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// targetType = The type of the property/field/etc. being stored to. |
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// setterValue = The value being stored. |
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var storeInSetter = setterValue as StLoc; |
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if (storeInSetter != null) |
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{ |
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// We'll move the stloc to top-level: |
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// callvirt set_Property(ldloc S_1, stloc v(binary.op(callvirt get_Property(ldloc S_1), value))) |
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// ==> stloc v(compound.op.new(callvirt get_Property(ldloc S_1), value)) |
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setterValue = storeInSetter.Value; |
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if (storeInSetter.Variable.Type.IsSmallIntegerType()) |
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{ |
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// 'stloc v' implicitly truncates the value. |
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// Ensure that type of 'v' matches the type of the property: |
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if (storeInSetter.Variable.Type.GetSize() != targetType.GetSize()) |
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return false; |
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if (storeInSetter.Variable.Type.GetSign() != targetType.GetSign()) |
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return false; |
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} |
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} |
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ILInstruction newInst; |
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if (UnwrapSmallIntegerConv(setterValue, out var smallIntConv) is BinaryNumericInstruction binary) |
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{ |
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if (compoundStore is StLoc) |
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{ |
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// transform local variables only for user-defined operators |
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return false; |
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} |
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if (!IsMatchingCompoundLoad(binary.Left, compoundStore, out var target, out var targetKind, out var finalizeMatch, forbiddenVariable: storeInSetter?.Variable)) |
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return false; |
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if (!ValidateCompoundAssign(binary, smallIntConv, targetType, context.Settings)) |
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return false; |
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context.Step($"Compound assignment (binary.numeric)", compoundStore); |
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finalizeMatch?.Invoke(context); |
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newInst = new NumericCompoundAssign( |
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binary, target, targetKind, binary.Right, |
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targetType, CompoundEvalMode.EvaluatesToNewValue); |
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} |
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else if (setterValue is Call operatorCall && operatorCall.Method.IsOperator) |
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{ |
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if (operatorCall.Arguments.Count == 0) |
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return false; |
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if (!IsMatchingCompoundLoad(operatorCall.Arguments[0], compoundStore, out var target, out var targetKind, out var finalizeMatch, forbiddenVariable: storeInSetter?.Variable)) |
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return false; |
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ILInstruction rhs; |
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if (operatorCall.Arguments.Count == 2) |
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{ |
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if (CSharp.ExpressionBuilder.GetAssignmentOperatorTypeFromMetadataName(operatorCall.Method.Name, context.Settings) == null) |
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return false; |
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rhs = operatorCall.Arguments[1]; |
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} |
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else if (operatorCall.Arguments.Count == 1) |
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{ |
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if (!(operatorCall.Method.Name == "op_Increment" || operatorCall.Method.Name == "op_Decrement")) |
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return false; |
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// use a dummy node so that we don't need a dedicated instruction for user-defined unary operator calls |
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rhs = new LdcI4(1); |
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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 (operatorCall.IsLifted) |
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return false; // TODO: add tests and think about whether nullables need special considerations |
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context.Step($"Compound assignment (user-defined binary)", compoundStore); |
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finalizeMatch?.Invoke(context); |
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newInst = new UserDefinedCompoundAssign(operatorCall.Method, CompoundEvalMode.EvaluatesToNewValue, |
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target, targetKind, rhs); |
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} |
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else if (setterValue is DynamicBinaryOperatorInstruction dynamicBinaryOp) |
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{ |
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if (!IsMatchingCompoundLoad(dynamicBinaryOp.Left, compoundStore, out var target, out var targetKind, out var finalizeMatch, forbiddenVariable: storeInSetter?.Variable)) |
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return false; |
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context.Step($"Compound assignment (dynamic binary)", compoundStore); |
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finalizeMatch?.Invoke(context); |
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newInst = new DynamicCompoundAssign(ToCompound(dynamicBinaryOp.Operation), dynamicBinaryOp.BinderFlags, target, dynamicBinaryOp.LeftArgumentInfo, dynamicBinaryOp.Right, dynamicBinaryOp.RightArgumentInfo, targetKind); |
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|
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static ExpressionType ToCompound(ExpressionType from) |
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{ |
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return from switch { |
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ExpressionType.Add => ExpressionType.AddAssign, |
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ExpressionType.AddChecked => ExpressionType.AddAssignChecked, |
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ExpressionType.And => ExpressionType.AndAssign, |
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ExpressionType.Divide => ExpressionType.DivideAssign, |
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ExpressionType.ExclusiveOr => ExpressionType.ExclusiveOrAssign, |
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ExpressionType.LeftShift => ExpressionType.LeftShiftAssign, |
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ExpressionType.Modulo => ExpressionType.ModuloAssign, |
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ExpressionType.Multiply => ExpressionType.MultiplyAssign, |
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ExpressionType.MultiplyChecked => ExpressionType.MultiplyAssignChecked, |
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ExpressionType.Or => ExpressionType.OrAssign, |
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ExpressionType.Power => ExpressionType.PowerAssign, |
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ExpressionType.RightShift => ExpressionType.RightShiftAssign, |
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ExpressionType.Subtract => ExpressionType.SubtractAssign, |
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ExpressionType.SubtractChecked => ExpressionType.SubtractAssignChecked, |
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_ => from |
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}; |
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} |
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} |
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else if (setterValue is Call concatCall && UserDefinedCompoundAssign.IsStringConcat(concatCall.Method)) |
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{ |
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// setterValue is a string.Concat() invocation |
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if (compoundStore is StLoc) |
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{ |
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// transform local variables only for user-defined operators |
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return false; |
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} |
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if (concatCall.Arguments.Count != 2) |
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return false; // for now we only support binary compound assignments |
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if (!targetType.IsKnownType(KnownTypeCode.String)) |
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return false; |
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if (!IsMatchingCompoundLoad(concatCall.Arguments[0], compoundStore, out var target, out var targetKind, out var finalizeMatch, forbiddenVariable: storeInSetter?.Variable)) |
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return false; |
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context.Step($"Compound assignment (string concatenation)", compoundStore); |
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finalizeMatch?.Invoke(context); |
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newInst = new UserDefinedCompoundAssign(concatCall.Method, CompoundEvalMode.EvaluatesToNewValue, |
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target, targetKind, concatCall.Arguments[1]); |
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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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newInst.AddILRange(setterValue); |
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if (storeInSetter != null) |
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{ |
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storeInSetter.Value = newInst; |
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newInst = storeInSetter; |
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context.RequestRerun(); // moving stloc to top-level might trigger inlining |
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} |
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compoundStore.ReplaceWith(newInst); |
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if (newInst.Parent is Block inlineAssignBlock && inlineAssignBlock.Kind == BlockKind.CallInlineAssign) |
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{ |
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// It's possible that we first replaced the instruction in an inline-assign helper block. |
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// In such a situation, we know from the block invariant that we're have a storeInSetter. |
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Debug.Assert(storeInSetter != null); |
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Debug.Assert(storeInSetter.Variable.IsSingleDefinition && storeInSetter.Variable.LoadCount == 1); |
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Debug.Assert(inlineAssignBlock.Instructions.Single() == storeInSetter); |
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Debug.Assert(inlineAssignBlock.FinalInstruction.MatchLdLoc(storeInSetter.Variable)); |
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// Block CallInlineAssign { stloc I_0(compound.op(...)); final: ldloc I_0 } |
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// --> compound.op(...) |
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inlineAssignBlock.ReplaceWith(storeInSetter.Value); |
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} |
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return true; |
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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) |
|
/// where neither 'stloc s' nor 'stloc l' truncates the value |
|
/// --> |
|
/// stloc s(stloc l(value)) |
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/// </code> |
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bool TransformInlineAssignmentLocal(Block block, int pos) |
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{ |
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var inst = block.Instructions[pos] as StLoc; |
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var nextInst = block.Instructions.ElementAtOrDefault(pos + 1) as StLoc; |
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if (inst == null || nextInst == null) |
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return false; |
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if (inst.Variable.Kind != VariableKind.StackSlot) |
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return false; |
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if (!(nextInst.Variable.Kind == VariableKind.Local || nextInst.Variable.Kind == VariableKind.Parameter)) |
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return false; |
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if (!nextInst.Value.MatchLdLoc(inst.Variable)) |
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return false; |
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if (IsImplicitTruncation(inst.Value, inst.Variable.Type, context.TypeSystem)) |
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{ |
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// 'stloc s' is implicitly truncating the stack value |
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return false; |
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} |
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if (IsImplicitTruncation(inst.Value, nextInst.Variable.Type, context.TypeSystem)) |
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{ |
|
// 'stloc l' is implicitly truncating the stack value |
|
return false; |
|
} |
|
if (nextInst.Variable.StackType == StackType.Ref) |
|
{ |
|
// ref locals need to be initialized when they are declared, so |
|
// we can only use inline assignments when we know that the |
|
// ref local is definitely assigned. |
|
// We don't have an easy way to check for that in this transform, |
|
// so avoid inline assignments to ref locals for now. |
|
return false; |
|
} |
|
context.Step("Inline assignment to local variable", inst); |
|
var value = inst.Value; |
|
var var = nextInst.Variable; |
|
var stackVar = inst.Variable; |
|
block.Instructions.RemoveAt(pos); |
|
nextInst.ReplaceWith(new StLoc(stackVar, new StLoc(var, value))); |
|
return true; |
|
} |
|
|
|
internal static bool IsImplicitTruncation(ILInstruction value, IType type, ICompilation compilation, bool allowNullableValue = false) |
|
{ |
|
return CheckImplicitTruncation(value, type, compilation, allowNullableValue) != ImplicitTruncationResult.ValuePreserved; |
|
} |
|
|
|
|
|
internal enum ImplicitTruncationResult : byte |
|
{ |
|
/// <summary> |
|
/// The value is not implicitly truncated. |
|
/// </summary> |
|
ValuePreserved, |
|
/// <summary> |
|
/// The value is implicitly truncated. |
|
/// </summary> |
|
ValueChanged, |
|
/// <summary> |
|
/// The value is implicitly truncated, but the sign of the target type can be changed to remove the truncation. |
|
/// </summary> |
|
ValueChangedDueToSignMismatch |
|
} |
|
|
|
/// <summary> |
|
/// Gets whether 'stobj type(..., value)' would evaluate to a different value than 'value' |
|
/// due to implicit truncation. |
|
/// </summary> |
|
internal static ImplicitTruncationResult CheckImplicitTruncation(ILInstruction value, IType type, ICompilation compilation, bool allowNullableValue = false) |
|
{ |
|
if (!type.IsSmallIntegerType()) |
|
{ |
|
// Implicit truncation in ILAst only happens for small integer types; |
|
// other types of implicit truncation in IL cause the ILReader to insert |
|
// conv instructions. |
|
return ImplicitTruncationResult.ValuePreserved; |
|
} |
|
// With small integer types, test whether the value might be changed by |
|
// truncation (based on type.GetSize()) followed by sign/zero extension (based on type.GetSign()). |
|
// (it's OK to have false-positives here if we're unsure) |
|
if (value.MatchLdcI4(out int val)) |
|
{ |
|
bool valueFits = (type.GetEnumUnderlyingType().GetDefinition()?.KnownTypeCode) switch { |
|
KnownTypeCode.Boolean => val == 0 || val == 1, |
|
KnownTypeCode.Byte => val >= byte.MinValue && val <= byte.MaxValue, |
|
KnownTypeCode.SByte => val >= sbyte.MinValue && val <= sbyte.MaxValue, |
|
KnownTypeCode.Int16 => val >= short.MinValue && val <= short.MaxValue, |
|
KnownTypeCode.UInt16 or KnownTypeCode.Char => val >= ushort.MinValue && val <= ushort.MaxValue, |
|
_ => false |
|
}; |
|
return valueFits ? ImplicitTruncationResult.ValuePreserved : ImplicitTruncationResult.ValueChanged; |
|
} |
|
else if (value is Conv conv) |
|
{ |
|
PrimitiveType primitiveType = type.ToPrimitiveType(); |
|
PrimitiveType convTargetType = conv.TargetType; |
|
if (convTargetType == primitiveType) |
|
return ImplicitTruncationResult.ValuePreserved; |
|
if (primitiveType.GetSize() == convTargetType.GetSize() && primitiveType.GetSign() != convTargetType.GetSign() && primitiveType.HasOppositeSign()) |
|
return ImplicitTruncationResult.ValueChangedDueToSignMismatch; |
|
return ImplicitTruncationResult.ValueChanged; |
|
} |
|
else if (value is Comp) |
|
{ |
|
return ImplicitTruncationResult.ValuePreserved; // comp returns 0 or 1, which always fits |
|
} |
|
else if (value is BinaryNumericInstruction bni) |
|
{ |
|
switch (bni.Operator) |
|
{ |
|
case BinaryNumericOperator.BitAnd: |
|
case BinaryNumericOperator.BitOr: |
|
case BinaryNumericOperator.BitXor: |
|
// If both input values fit into the type without truncation, |
|
// the result of a binary operator will also fit. |
|
var leftTruncation = CheckImplicitTruncation(bni.Left, type, compilation, allowNullableValue); |
|
// If the left side is truncating and a sign change is not possible we do not need to evaluate the right side |
|
if (leftTruncation == ImplicitTruncationResult.ValueChanged) |
|
return ImplicitTruncationResult.ValueChanged; |
|
var rightTruncation = CheckImplicitTruncation(bni.Right, type, compilation, allowNullableValue); |
|
return CommonImplicitTruncation(leftTruncation, rightTruncation); |
|
} |
|
} |
|
else if (value is IfInstruction ifInst) |
|
{ |
|
var trueTruncation = CheckImplicitTruncation(ifInst.TrueInst, type, compilation, allowNullableValue); |
|
// If the true branch is truncating and a sign change is not possible we do not need to evaluate the false branch |
|
if (trueTruncation == ImplicitTruncationResult.ValueChanged) |
|
return ImplicitTruncationResult.ValueChanged; |
|
var falseTruncation = CheckImplicitTruncation(ifInst.FalseInst, type, compilation, allowNullableValue); |
|
return CommonImplicitTruncation(trueTruncation, falseTruncation); |
|
} |
|
else |
|
{ |
|
IType inferredType = value.InferType(compilation); |
|
if (allowNullableValue) |
|
{ |
|
inferredType = NullableType.GetUnderlyingType(inferredType); |
|
} |
|
if (inferredType.Kind != TypeKind.Unknown) |
|
{ |
|
var inferredPrimitive = inferredType.ToPrimitiveType(); |
|
var primitiveType = type.ToPrimitiveType(); |
|
|
|
bool sameSign = inferredPrimitive.GetSign() == primitiveType.GetSign(); |
|
if (inferredPrimitive.GetSize() <= primitiveType.GetSize() && sameSign) |
|
return ImplicitTruncationResult.ValuePreserved; |
|
if (inferredPrimitive.GetSize() == primitiveType.GetSize() && !sameSign && primitiveType.HasOppositeSign()) |
|
return ImplicitTruncationResult.ValueChangedDueToSignMismatch; |
|
return ImplicitTruncationResult.ValueChanged; |
|
} |
|
} |
|
// In unknown cases, assume that the value might be changed by truncation. |
|
return ImplicitTruncationResult.ValueChanged; |
|
} |
|
|
|
private static ImplicitTruncationResult CommonImplicitTruncation(ImplicitTruncationResult left, ImplicitTruncationResult right) |
|
{ |
|
if (left == right) |
|
return left; |
|
// Note: in all cases where left!=right, we return ValueChanged: |
|
// if only one side can be fixed by changing the sign, we don't want to change the sign of the other side. |
|
return ImplicitTruncationResult.ValueChanged; |
|
} |
|
|
|
/// <summary> |
|
/// Gets whether 'inst' is a possible store for use as a compound store. |
|
/// </summary> |
|
/// <remarks> |
|
/// Output parameters: |
|
/// storeType: The type of the value being stored. |
|
/// value: The value being stored (will be analyzed further to detect compound assignments) |
|
/// |
|
/// Every IsCompoundStore() call should be followed by an IsMatchingCompoundLoad() call. |
|
/// </remarks> |
|
static bool IsCompoundStore(ILInstruction inst, out IType storeType, |
|
out ILInstruction value, ICompilation compilation) |
|
{ |
|
value = null; |
|
storeType = null; |
|
if (inst is StObj stobj) |
|
{ |
|
// stobj.Type may just be 'int' (due to stind.i4) when we're actually operating on a 'ref MyEnum'. |
|
// Try to determine the real type of the object we're modifying: |
|
storeType = stobj.Target.InferType(compilation); |
|
if (storeType is ByReferenceType refType) |
|
{ |
|
if (TypeUtils.IsCompatibleTypeForMemoryAccess(refType.ElementType, stobj.Type)) |
|
{ |
|
storeType = refType.ElementType; |
|
} |
|
else |
|
{ |
|
storeType = stobj.Type; |
|
} |
|
} |
|
else if (storeType is PointerType pointerType) |
|
{ |
|
if (TypeUtils.IsCompatibleTypeForMemoryAccess(pointerType.ElementType, stobj.Type)) |
|
{ |
|
storeType = pointerType.ElementType; |
|
} |
|
else |
|
{ |
|
storeType = stobj.Type; |
|
} |
|
} |
|
else |
|
{ |
|
storeType = stobj.Type; |
|
} |
|
value = stobj.Value; |
|
return SemanticHelper.IsPure(stobj.Target.Flags); |
|
} |
|
else if (inst is CallInstruction call && (call.OpCode == OpCode.Call || call.OpCode == OpCode.CallVirt)) |
|
{ |
|
if (call.Method.Parameters.Count == 0) |
|
{ |
|
return false; |
|
} |
|
foreach (var arg in call.Arguments.SkipLast(1)) |
|
{ |
|
if (arg.MatchStLoc(out var v) && v.IsSingleDefinition && v.LoadCount == 1) |
|
{ |
|
continue; // OK, IsMatchingCompoundLoad can perform an adjustment in this special case |
|
} |
|
if (!SemanticHelper.IsPure(arg.Flags)) |
|
{ |
|
return false; |
|
} |
|
} |
|
storeType = call.Method.Parameters.Last().Type; |
|
value = call.Arguments.Last(); |
|
return IsSameMember(call.Method, (call.Method.AccessorOwner as IProperty)?.Setter); |
|
} |
|
else if (inst is StLoc stloc && (stloc.Variable.Kind == VariableKind.Local || stloc.Variable.Kind == VariableKind.Parameter)) |
|
{ |
|
storeType = stloc.Variable.Type; |
|
value = stloc.Value; |
|
return true; |
|
} |
|
else |
|
{ |
|
return false; |
|
} |
|
} |
|
|
|
/// <summary> |
|
/// Checks whether 'load' and 'store' both access the same store, and can be combined to a compound assignment. |
|
/// </summary> |
|
/// <param name="load">The load instruction to test.</param> |
|
/// <param name="store">The compound store to test against. Must have previously been tested via IsCompoundStore()</param> |
|
/// <param name="target">The target to use for the compound assignment instruction.</param> |
|
/// <param name="targetKind">The target kind to use for the compound assignment instruction.</param> |
|
/// <param name="finalizeMatch">If set to a non-null value, call this delegate to fix up minor mismatches between getter and setter.</param> |
|
/// <param name="forbiddenVariable"> |
|
/// If given a non-null value, this function returns false if the forbiddenVariable is used in the load/store instructions. |
|
/// Some transforms effectively move a store around, |
|
/// which is only valid if the variable stored to does not occur in the compound load/store. |
|
/// </param> |
|
/// <param name="previousInstruction"> |
|
/// Instruction preceding the load. |
|
/// </param> |
|
static bool IsMatchingCompoundLoad(ILInstruction load, ILInstruction store, |
|
out ILInstruction target, out CompoundTargetKind targetKind, |
|
out Action<ILTransformContext> finalizeMatch, |
|
ILVariable forbiddenVariable = null, |
|
ILInstruction previousInstruction = null) |
|
{ |
|
target = null; |
|
targetKind = 0; |
|
finalizeMatch = null; |
|
if (load is LdObj ldobj && store is StObj stobj) |
|
{ |
|
Debug.Assert(SemanticHelper.IsPure(stobj.Target.Flags)); |
|
if (!SemanticHelper.IsPure(ldobj.Target.Flags)) |
|
return false; |
|
if (forbiddenVariable != null && forbiddenVariable.IsUsedWithin(ldobj.Target)) |
|
return false; |
|
target = ldobj.Target; |
|
targetKind = CompoundTargetKind.Address; |
|
if (ldobj.Target.Match(stobj.Target).Success) |
|
{ |
|
return true; |
|
} |
|
else if (IsDuplicatedAddressComputation(stobj.Target, ldobj.Target)) |
|
{ |
|
// Use S_0 as target, so that S_0 can later be eliminated by inlining. |
|
// (we can't eliminate previousInstruction right now, because it's before the transform's starting instruction) |
|
target = stobj.Target; |
|
return true; |
|
} |
|
else |
|
{ |
|
return false; |
|
} |
|
} |
|
else if (MatchingGetterAndSetterCalls(load as CallInstruction, store as CallInstruction, out finalizeMatch)) |
|
{ |
|
if (forbiddenVariable != null && forbiddenVariable.IsUsedWithin(load)) |
|
return false; |
|
target = load; |
|
targetKind = CompoundTargetKind.Property; |
|
return true; |
|
} |
|
else if (load is LdLoc ldloc && store is StLoc stloc && ILVariableEqualityComparer.Instance.Equals(ldloc.Variable, stloc.Variable)) |
|
{ |
|
if (ILVariableEqualityComparer.Instance.Equals(ldloc.Variable, forbiddenVariable)) |
|
return false; |
|
target = new LdLoca(ldloc.Variable).WithILRange(ldloc); |
|
targetKind = CompoundTargetKind.Address; |
|
finalizeMatch = context => context.Function.RecombineVariables(ldloc.Variable, stloc.Variable); |
|
return true; |
|
} |
|
else |
|
{ |
|
return false; |
|
} |
|
|
|
bool IsDuplicatedAddressComputation(ILInstruction storeTarget, ILInstruction loadTarget) |
|
{ |
|
// Sometimes roslyn duplicates the address calculation: |
|
// stloc S_0(ldloc refParam) |
|
// stloc V_0(ldobj System.Int32(ldloc refParam)) |
|
// stobj System.Int32(ldloc S_0, binary.add.i4(ldloc V_0, ldc.i4 1)) |
|
while (storeTarget is LdFlda storeLdFlda && loadTarget is LdFlda loadLdFlda) |
|
{ |
|
if (!storeLdFlda.Field.Equals(loadLdFlda.Field)) |
|
return false; |
|
storeTarget = storeLdFlda.Target; |
|
loadTarget = loadLdFlda.Target; |
|
} |
|
if (!storeTarget.MatchLdLoc(out var s)) |
|
return false; |
|
if (!(s.Kind == VariableKind.StackSlot && s.IsSingleDefinition && s != forbiddenVariable)) |
|
return false; |
|
if (s.StoreInstructions.SingleOrDefault() != previousInstruction) |
|
return false; |
|
return previousInstruction is StLoc addressStore && addressStore.Value.Match(loadTarget).Success; |
|
} |
|
} |
|
|
|
/// <code> |
|
/// stobj(target, binary.add(stloc l(ldobj(target)), ldc.i4 1)) |
|
/// where target is pure and does not use 'l', and the 'stloc l' does not truncate |
|
/// --> |
|
/// stloc l(compound.op.old(ldobj(target), ldc.i4 1)) |
|
/// |
|
/// -or- |
|
/// |
|
/// call set_Prop(args..., binary.add(stloc l(call get_Prop(args...)), ldc.i4 1)) |
|
/// where args.. are pure and do not use 'l', and the 'stloc l' does not truncate |
|
/// --> |
|
/// stloc l(compound.op.old(call get_Prop(target), ldc.i4 1)) |
|
/// </code> |
|
/// <remarks> |
|
/// This pattern is used for post-increment by legacy csc. |
|
/// |
|
/// Even though this transform operates only on a single expression, it's not an expression transform |
|
/// as the result value of the expression changes (this is OK only for statements in a block). |
|
/// </remarks> |
|
bool TransformPostIncDecOperatorWithInlineStore(Block block, int pos) |
|
{ |
|
var store = block.Instructions[pos]; |
|
if (!IsCompoundStore(store, out var targetType, out var value, context.TypeSystem)) |
|
{ |
|
return false; |
|
} |
|
StLoc stloc; |
|
var binary = UnwrapSmallIntegerConv(value, out var conv) as BinaryNumericInstruction; |
|
if (binary != null && (binary.Right.MatchLdcI(1) || binary.Right.MatchLdcF4(1) || binary.Right.MatchLdcF8(1))) |
|
{ |
|
if (!(binary.Operator == BinaryNumericOperator.Add || binary.Operator == BinaryNumericOperator.Sub)) |
|
return false; |
|
|
|
if (conv is not null) |
|
{ |
|
var primitiveType = targetType.ToPrimitiveType(); |
|
if (primitiveType.GetSize() == conv.TargetType.GetSize() && primitiveType.GetSign() != conv.TargetType.GetSign()) |
|
targetType = SwapSign(targetType, context.TypeSystem); |
|
} |
|
|
|
if (!ValidateCompoundAssign(binary, conv, targetType, context.Settings)) |
|
return false; |
|
stloc = binary.Left as StLoc; |
|
} |
|
else if (value is Call operatorCall && operatorCall.Method.IsOperator && operatorCall.Arguments.Count == 1) |
|
{ |
|
if (!(operatorCall.Method.Name == "op_Increment" || operatorCall.Method.Name == "op_Decrement")) |
|
return false; |
|
if (operatorCall.IsLifted) |
|
return false; // TODO: add tests and think about whether nullables need special considerations |
|
stloc = operatorCall.Arguments[0] as StLoc; |
|
} |
|
else |
|
{ |
|
return false; |
|
} |
|
if (stloc == null) |
|
return false; |
|
if (!(stloc.Variable.Kind == VariableKind.Local || stloc.Variable.Kind == VariableKind.StackSlot)) |
|
return false; |
|
if (!IsMatchingCompoundLoad(stloc.Value, store, out var target, out var targetKind, out var finalizeMatch, forbiddenVariable: stloc.Variable)) |
|
return false; |
|
if (IsImplicitTruncation(stloc.Value, stloc.Variable.Type, context.TypeSystem)) |
|
return false; |
|
context.Step("TransformPostIncDecOperatorWithInlineStore", store); |
|
finalizeMatch?.Invoke(context); |
|
if (binary != null) |
|
{ |
|
block.Instructions[pos] = new StLoc(stloc.Variable, new NumericCompoundAssign( |
|
binary, target, targetKind, binary.Right, targetType, CompoundEvalMode.EvaluatesToOldValue)); |
|
} |
|
else |
|
{ |
|
Call operatorCall = (Call)value; |
|
block.Instructions[pos] = new StLoc(stloc.Variable, new UserDefinedCompoundAssign( |
|
operatorCall.Method, CompoundEvalMode.EvaluatesToOldValue, target, targetKind, new LdcI4(1))); |
|
} |
|
return true; |
|
} |
|
|
|
/// <code> |
|
/// stloc tmp(ldobj(target)) |
|
/// stobj(target, binary.op(ldloc tmp, ldc.i4 1)) |
|
/// target is pure and does not use 'tmp', 'stloc does not truncate' |
|
/// --> |
|
/// stloc tmp(compound.op.old(ldobj(target), ldc.i4 1)) |
|
/// </code> |
|
/// This is usually followed by inlining or eliminating 'tmp'. |
|
/// |
|
/// Local variables use a similar pattern, also detected by this function: |
|
/// <code> |
|
/// stloc tmp(ldloc target) |
|
/// stloc target(binary.op(ldloc tmp, ldc.i4 1)) |
|
/// --> |
|
/// stloc tmp(compound.op.old(ldloca target, ldc.i4 1)) |
|
/// </code> |
|
/// <remarks> |
|
/// This pattern occurs with legacy csc for static fields, and with Roslyn for most post-increments. |
|
/// </remarks> |
|
bool TransformPostIncDecOperator(Block block, int i) |
|
{ |
|
var inst = block.Instructions[i] as StLoc; |
|
var store = block.Instructions.ElementAtOrDefault(i + 1); |
|
if (inst == null || store == null) |
|
return false; |
|
var tmpVar = inst.Variable; |
|
if (!IsCompoundStore(store, out var targetType, out var value, context.TypeSystem)) |
|
return false; |
|
var truncation = CheckImplicitTruncation(inst.Value, targetType, context.TypeSystem); |
|
if (truncation == ImplicitTruncationResult.ValueChanged) |
|
{ |
|
// 'stloc tmp' is implicitly truncating the value |
|
return false; |
|
} |
|
if (truncation == ImplicitTruncationResult.ValueChangedDueToSignMismatch) |
|
{ |
|
if (!(store is StObj stObj && stObj.Type.Equals(targetType))) |
|
{ |
|
// We cannot apply the sign change, so we can't fix the truncation |
|
return false; |
|
} |
|
} |
|
if (!IsMatchingCompoundLoad(inst.Value, store, out var target, out var targetKind, out var finalizeMatch, |
|
forbiddenVariable: inst.Variable, |
|
previousInstruction: block.Instructions.ElementAtOrDefault(i - 1))) |
|
{ |
|
return false; |
|
} |
|
if (UnwrapSmallIntegerConv(value, out var conv) is BinaryNumericInstruction binary) |
|
{ |
|
if (!(binary.Operator == BinaryNumericOperator.Add || binary.Operator == BinaryNumericOperator.Sub)) |
|
return false; |
|
if (!binary.Left.MatchLdLoc(tmpVar)) |
|
return false; |
|
if (targetType is PointerType ptrType) |
|
{ |
|
var right = PointerArithmeticOffset.Detect(binary.Right, ptrType.ElementType, binary.CheckForOverflow); |
|
if (right is null || !right.MatchLdcI(1)) |
|
return false; |
|
} |
|
else if (!(binary.Right.MatchLdcI(1) || binary.Right.MatchLdcF4(1) || binary.Right.MatchLdcF8(1))) |
|
return false; |
|
if (truncation == ImplicitTruncationResult.ValueChangedDueToSignMismatch && store is StObj stObj) |
|
{ |
|
// Change the sign of the type to skip implicit truncation |
|
stObj.Type = targetType = SwapSign(targetType, context.TypeSystem); |
|
} |
|
if (!ValidateCompoundAssign(binary, conv, targetType, context.Settings)) |
|
return false; |
|
context.Step("TransformPostIncDecOperator (builtin)", inst); |
|
finalizeMatch?.Invoke(context); |
|
inst.Value = new NumericCompoundAssign(binary, target, targetKind, binary.Right, |
|
targetType, CompoundEvalMode.EvaluatesToOldValue); |
|
} |
|
else if (value is Call operatorCall && operatorCall.Method.IsOperator && operatorCall.Arguments.Count == 1) |
|
{ |
|
if (!operatorCall.Arguments[0].MatchLdLoc(tmpVar)) |
|
return false; |
|
if (!(operatorCall.Method.Name == "op_Increment" || operatorCall.Method.Name == "op_Decrement")) |
|
return false; |
|
if (operatorCall.IsLifted) |
|
return false; // TODO: add tests and think about whether nullables need special considerations |
|
context.Step("TransformPostIncDecOperator (user-defined)", inst); |
|
Debug.Assert(truncation == ImplicitTruncationResult.ValuePreserved); |
|
finalizeMatch?.Invoke(context); |
|
inst.Value = new UserDefinedCompoundAssign(operatorCall.Method, |
|
CompoundEvalMode.EvaluatesToOldValue, target, targetKind, new LdcI4(1)); |
|
} |
|
else |
|
{ |
|
return false; |
|
} |
|
block.Instructions.RemoveAt(i + 1); |
|
if (inst.Variable.IsSingleDefinition && inst.Variable.LoadCount == 0) |
|
{ |
|
// dead store -> it was a statement-level post-increment |
|
inst.ReplaceWith(inst.Value); |
|
} |
|
return true; |
|
} |
|
|
|
static bool IsSameMember(IMember a, IMember b) |
|
{ |
|
if (a == null || b == null) |
|
return false; |
|
a = a.MemberDefinition; |
|
b = b.MemberDefinition; |
|
return a.Equals(b); |
|
} |
|
} |
|
}
|
|
|