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Refactor sub pattern detection into loop to allow continuations of outer patterns.

pull/3049/head
Siegfried Pammer 2 years ago
parent
8cb3a67c0c
commit
1cb4e77f06
2 changed files with 96 additions and 35 deletions
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  1. 36
      ICSharpCode.Decompiler.Tests/TestCases/Pretty/PatternMatching.cs
  2. 95
      ICSharpCode.Decompiler/IL/Transforms/PatternMatchingTransform.cs

36
ICSharpCode.Decompiler.Tests/TestCases/Pretty/PatternMatching.cs
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@ -331,6 +331,18 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty @@ -331,6 +331,18 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
}
}
public void RecursivePattern_TypeAndConst(object x)
{
if (x is X { Obj: string obj, I: 42 })
{
Console.WriteLine("Test " + obj);
}
else
{
Console.WriteLine("not Test");
}
}
public void RecursivePattern_Constant(object obj)
{
if (obj is X { Obj: null } x)
@ -450,6 +462,30 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty @@ -450,6 +462,30 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
Console.WriteLine("not Test");
}
}
public void RecursivePatternValueType_VarLengthPattern_SwappedProps(object obj)
{
if (obj is S { Text: { Length: var length }, I: 42 } s)
{
Console.WriteLine("Test " + s.I + ": " + length);
}
else
{
Console.WriteLine("not Test");
}
}
public void RecursivePattern_VarLengthPattern_SwappedProps(object obj)
{
if (obj is X { Text: { Length: var length }, I: 42 } x)
{
Console.WriteLine("Test " + x.I + ": " + length);
}
else
{
Console.WriteLine("not Test");
}
}
#endif
private bool F()
{

95
ICSharpCode.Decompiler/IL/Transforms/PatternMatchingTransform.cs
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@ -180,15 +180,37 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -180,15 +180,37 @@ namespace ICSharpCode.Decompiler.IL.Transforms
block.Instructions.RemoveRange(pos, ifInst.ChildIndex - pos);
v.Kind = VariableKind.PatternLocal;
if (trueInst.MatchBranch(out var trueBlock) && trueBlock.IncomingEdgeCount == 1 && trueBlock.Parent == container)
{
DetectPropertySubPatterns((MatchInstruction)ifInst.Condition, trueBlock, falseInst, context, ref cfg);
}
DetectPropertySubPatterns((MatchInstruction)ifInst.Condition, trueInst, falseInst, container, context, ref cfg);
return true;
}
private static void DetectPropertySubPatterns(MatchInstruction parentPattern, Block block, ILInstruction parentFalseInst, ILTransformContext context, ref ControlFlowGraph? cfg)
private static ILInstruction? DetectPropertySubPatterns(MatchInstruction parentPattern, ILInstruction? trueInst,
ILInstruction parentFalseInst, BlockContainer container, ILTransformContext context, ref ControlFlowGraph? cfg)
{
ILInstruction? prevTrueInst = trueInst;
while (trueInst != null)
{
Block? trueBlock = trueInst as Block;
if (!(trueBlock != null || trueInst.MatchBranch(out trueBlock)))
{
break;
}
if (!(trueBlock.IncomingEdgeCount == 1 && trueBlock.Parent == container))
{
break;
}
trueInst = DetectPropertySubPattern(parentPattern, trueBlock, parentFalseInst, context, ref cfg);
if (trueInst != null)
{
prevTrueInst = trueInst;
}
}
return prevTrueInst;
}
private static ILInstruction? DetectPropertySubPattern(MatchInstruction parentPattern, Block block,
ILInstruction parentFalseInst, ILTransformContext context, ref ControlFlowGraph? cfg)
{
// if (match.notnull.type[System.String] (V_0 = callvirt get_C(ldloc V_2))) br IL_0022
// br IL_0037
@ -199,7 +221,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -199,7 +221,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
{
if (!DetectExitPoints.CompatibleExitInstruction(parentFalseInst, trueInst))
{
return;
return null;
}
ExtensionMethods.Swap(ref trueInst, ref falseInst);
negate = true;
@ -208,11 +230,11 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -208,11 +230,11 @@ namespace ICSharpCode.Decompiler.IL.Transforms
{
if (!PropertyOrFieldAccess(operand, out var target, out _))
{
return;
return null;
}
if (!target.MatchLdLocRef(parentPattern.Variable))
{
return;
return null;
}
context.Step("Move property sub pattern", condition);
if (negate)
@ -225,40 +247,36 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -225,40 +247,36 @@ namespace ICSharpCode.Decompiler.IL.Transforms
{
if (!target.MatchLdLocRef(parentPattern.Variable))
{
return;
return null;
}
context.Step("Move property sub pattern", condition);
parentPattern.SubPatterns.Add(new Comp(negate ? ComparisonKind.Equality : ComparisonKind.Inequality, Sign.None, condition, new LdcI4(0)));
}
else
{
return;
return null;
}
block.Instructions.Clear();
block.Instructions.Add(trueInst);
if (trueInst.MatchBranch(out var trueBlock) && trueBlock.IncomingEdgeCount == 1 && trueBlock.Parent == block.Parent)
{
DetectPropertySubPatterns(parentPattern, trueBlock, falseInst, context, ref cfg);
}
return trueInst;
}
else if (block.Instructions[0].MatchStLoc(out var targetVariable, out var operand))
{
if (!PropertyOrFieldAccess(operand, out var target, out var member))
{
return;
return null;
}
if (!target.MatchLdLocRef(parentPattern.Variable))
{
return;
return null;
}
if (!targetVariable.Type.Equals(member.ReturnType))
{
return;
return null;
}
if (!CheckAllUsesDominatedBy(targetVariable, (BlockContainer)block.Parent!, block, block.Instructions[0], null, context, ref cfg))
{
return;
return null;
}
context.Step("Property var pattern", block);
var varPattern = new MatchInstruction(targetVariable, operand)
@ -266,22 +284,33 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -266,22 +284,33 @@ namespace ICSharpCode.Decompiler.IL.Transforms
parentPattern.SubPatterns.Add(varPattern);
block.Instructions.RemoveAt(0);
targetVariable.Kind = VariableKind.PatternLocal;
if (!MatchNullCheckPattern(block, varPattern, parentFalseInst, context, ref cfg))
var instructionAfterNullCheck = MatchNullCheckPattern(block, varPattern, parentFalseInst, context, ref cfg);
if (instructionAfterNullCheck != null)
{
if (targetVariable.Type.IsReferenceType == false)
{
DetectPropertySubPatterns(varPattern, block, parentFalseInst, context, ref cfg);
}
DetectPropertySubPatterns(parentPattern, block, parentFalseInst, context, ref cfg);
return DetectPropertySubPatterns(varPattern, instructionAfterNullCheck, parentFalseInst, (BlockContainer)block.Parent!, context, ref cfg);
}
else if (targetVariable.Type.IsReferenceType == false)
{
return DetectPropertySubPatterns(varPattern, block, parentFalseInst, (BlockContainer)block.Parent!, context, ref cfg);
}
else
{
return block;
}
}
else
{
return null;
}
}
private static bool MatchNullCheckPattern(Block block, MatchInstruction varPattern, ILInstruction parentFalseInst, ILTransformContext context, ref ControlFlowGraph? cfg)
private static ILInstruction? MatchNullCheckPattern(Block block, MatchInstruction varPattern,
ILInstruction parentFalseInst, ILTransformContext context, ref ControlFlowGraph? cfg)
{
if (!MatchBlockContainingOneCondition(block, out var condition, out var trueInst, out var falseInst))
{
return false;
return null;
}
if (condition.MatchCompEqualsNull(out var arg) && arg.MatchLdLoc(varPattern.Variable))
{
@ -292,21 +321,17 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -292,21 +321,17 @@ namespace ICSharpCode.Decompiler.IL.Transforms
}
else
{
return false;
return null;
}
if (!DetectExitPoints.CompatibleExitInstruction(falseInst, parentFalseInst))
{
return false;
return null;
}
context.Step("Null check pattern", block);
varPattern.CheckNotNull = true;
block.Instructions.Clear();
block.Instructions.Add(trueInst);
if (trueInst.MatchBranch(out var trueBlock) && trueBlock.IncomingEdgeCount == 1 && trueBlock.Parent == block.Parent)
{
DetectPropertySubPatterns(varPattern, trueBlock, falseInst, context, ref cfg);
}
return true;
return trueInst;
}
private static bool PropertyOrFieldAccess(ILInstruction operand, [NotNullWhen(true)] out ILInstruction? target, [NotNullWhen(true)] out IMember? member)
@ -466,7 +491,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms @@ -466,7 +491,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
// the pattern matching machinery to an offset belonging to an instruction in the then-block.
unboxBlock.SetILRange(unboxBlock.Instructions[0]);
storeToV.Variable.Kind = VariableKind.PatternLocal;
DetectPropertySubPatterns((MatchInstruction)ifInst.Condition, unboxBlock, falseInst, context, ref cfg);
DetectPropertySubPatterns((MatchInstruction)ifInst.Condition, unboxBlock, falseInst, container, context, ref cfg);
return true;
}

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