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Add support for pattern matching in UsingTransform.

pull/2461/head
Siegfried Pammer 4 years ago
parent
665c731cfc
commit
96db0a5472
1 changed files with 93 additions and 32 deletions
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  1. 125
      ICSharpCode.Decompiler/IL/Transforms/UsingTransform.cs

125
ICSharpCode.Decompiler/IL/Transforms/UsingTransform.cs
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@ -37,12 +37,18 @@ namespace ICSharpCode.Decompiler.IL.Transforms
this.context = context;
for (int i = block.Instructions.Count - 1; i >= 0; i--)
{
if (!TransformUsing(block, i) && !TransformUsingVB(block, i) && !TransformAsyncUsing(block, i))
if (TransformUsing(block, i))
{
continue;
}
if (TransformUsingVB(block, i))
{
continue;
}
if (TransformAsyncUsing(block, i))
{
continue;
// This happens in some cases:
// Use correct index after transformation.
if (i >= block.Instructions.Count)
i = block.Instructions.Count;
}
}
}
@ -74,9 +80,9 @@ namespace ICSharpCode.Decompiler.IL.Transforms
/// </summary>
bool TransformUsing(Block block, int i)
{
if (i < 1)
if (i + 1 >= block.Instructions.Count)
return false;
if (!(block.Instructions[i] is TryFinally tryFinally) || !(block.Instructions[i - 1] is StLoc storeInst))
if (!(block.Instructions[i + 1] is TryFinally tryFinally) || !(block.Instructions[i] is StLoc storeInst))
return false;
if (!(storeInst.Value.MatchLdNull() || CheckResourceType(storeInst.Variable.Type)))
return false;
@ -88,12 +94,14 @@ namespace ICSharpCode.Decompiler.IL.Transforms
return false;
if (storeInst.Variable.StoreInstructions.Count > 1)
return false;
if (!(tryFinally.FinallyBlock is BlockContainer container) || !MatchDisposeBlock(container, storeInst.Variable, storeInst.Value.MatchLdNull()))
if (!(tryFinally.FinallyBlock is BlockContainer container))
return false;
if (!MatchDisposeBlock(container, storeInst.Variable, storeInst.Value.MatchLdNull()))
return false;
context.Step("UsingTransform", tryFinally);
storeInst.Variable.Kind = VariableKind.UsingLocal;
block.Instructions.RemoveAt(i);
block.Instructions[i - 1] = new UsingInstruction(storeInst.Variable, storeInst.Value, tryFinally.TryBlock) {
block.Instructions.RemoveAt(i + 1);
block.Instructions[i] = new UsingInstruction(storeInst.Variable, storeInst.Value, tryFinally.TryBlock) {
IsRefStruct = context.Settings.IntroduceRefModifiersOnStructs && storeInst.Variable.Type.Kind == TypeKind.Struct && storeInst.Variable.Type.IsByRefLike
}.WithILRange(storeInst);
return true;
@ -127,6 +135,8 @@ namespace ICSharpCode.Decompiler.IL.Transforms
/// </summary>
bool TransformUsingVB(Block block, int i)
{
if (i >= block.Instructions.Count)
return false;
if (!(block.Instructions[i] is TryFinally tryFinally))
return false;
if (!(tryFinally.TryBlock is BlockContainer tryContainer && tryContainer.EntryPoint.Instructions.FirstOrDefault() is StLoc storeInst))
@ -175,41 +185,64 @@ namespace ICSharpCode.Decompiler.IL.Transforms
return true;
}
bool MatchDisposeBlock(BlockContainer container, ILVariable objVar, bool usingNull, in string disposeMethodFullName = "System.IDisposable.Dispose", KnownTypeCode disposeTypeCode = KnownTypeCode.IDisposable)
/// finally BlockContainer {
/// Block IL_0012(incoming: 1) {
/// if (comp(ldloc obj != ldnull)) Block IL_001a {
/// callvirt Dispose(obj)
/// }
/// leave IL_0012(nop)
/// }
/// }
bool MatchDisposeBlock(BlockContainer container, ILVariable objVar, bool usingNull,
in string disposeMethodFullName = "System.IDisposable.Dispose",
KnownTypeCode disposeTypeCode = KnownTypeCode.IDisposable)
{
var entryPoint = container.EntryPoint;
if (entryPoint.Instructions.Count < 2 || entryPoint.Instructions.Count > 3 || entryPoint.IncomingEdgeCount != 1)
if (entryPoint.IncomingEdgeCount != 1)
return false;
int leaveIndex = entryPoint.Instructions.Count == 2 ? 1 : 2;
int checkIndex = entryPoint.Instructions.Count == 2 ? 0 : 1;
int castIndex = entryPoint.Instructions.Count == 3 ? 0 : -1;
var checkInst = entryPoint.Instructions[checkIndex];
int pos = 0;
bool isReference = objVar.Type.IsReferenceType != false;
if (castIndex > -1)
// optional:
// stloc temp(isinst TDisposable(ldloc obj))
if (entryPoint.Instructions.ElementAtOrDefault(pos).MatchStLoc(out var tempVar, out var isinst))
{
if (!entryPoint.Instructions[castIndex].MatchStLoc(out var tempVar, out var isinst))
return false;
if (!isinst.MatchIsInst(out var load, out var disposableType) || !load.MatchLdLoc(objVar) || !disposableType.IsKnownType(disposeTypeCode))
if (!isinst.MatchIsInst(out var load, out var disposableType) || !load.MatchLdLoc(objVar)
|| !disposableType.IsKnownType(disposeTypeCode))
{
return false;
}
if (!tempVar.IsSingleDefinition)
return false;
isReference = true;
if (!MatchDisposeCheck(tempVar, checkInst, isReference, usingNull, out int numObjVarLoadsInCheck, disposeMethodFullName, disposeTypeCode))
return false;
if (tempVar.LoadCount != numObjVarLoadsInCheck)
return false;
pos++;
objVar = tempVar;
}
else
// if (comp(ldloc obj != ldnull)) Block IL_001a {
// callvirt Dispose(obj)
// }
var checkInst = entryPoint.Instructions.ElementAtOrDefault(pos);
if (checkInst == null)
return false;
if (!MatchDisposeCheck(objVar, checkInst, isReference, usingNull,
out int numObjVarLoadsInCheck, disposeMethodFullName, disposeTypeCode))
{
if (!MatchDisposeCheck(objVar, checkInst, isReference, usingNull, out _, disposeMethodFullName, disposeTypeCode))
return false;
return false;
}
if (!entryPoint.Instructions[leaveIndex].MatchLeave(container, out var returnValue) || !returnValue.MatchNop())
// make sure the (optional) temporary is used only in the dispose check
if (pos > 0 && objVar.LoadCount != numObjVarLoadsInCheck)
return false;
return true;
pos++;
// make sure, the finally ends in a leave(nop) instruction.
if (!entryPoint.Instructions.ElementAtOrDefault(pos).MatchLeave(container, out var returnValue))
return false;
if (!returnValue.MatchNop())
return false;
// leave is the last instruction
return (pos + 1) == entryPoint.Instructions.Count;
}
bool MatchDisposeCheck(ILVariable objVar, ILInstruction checkInst, bool isReference, bool usingNull, out int numObjVarLoadsInCheck, string disposeMethodFullName, KnownTypeCode disposeTypeCode)
bool MatchDisposeCheck(ILVariable objVar, ILInstruction checkInst, bool isReference, bool usingNull,
out int numObjVarLoadsInCheck, string disposeMethodFullName, KnownTypeCode disposeTypeCode)
{
numObjVarLoadsInCheck = 2;
ILInstruction disposeInvocation;
@ -283,7 +316,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
// reference types have a null check.
if (!checkInst.MatchIfInstruction(out var condition, out var disposeInst))
return false;
if (!condition.MatchCompNotEquals(out var left, out var right) || !left.MatchLdLoc(objVar) || !right.MatchLdNull())
if (!MatchNullCheckOrTypeCheck(condition, ref objVar, disposeTypeCode))
return false;
if (!(disposeInst is Block disposeBlock) || disposeBlock.Instructions.Count != 1)
return false;
@ -348,6 +381,32 @@ namespace ICSharpCode.Decompiler.IL.Transforms
}
}
bool MatchNullCheckOrTypeCheck(ILInstruction condition, ref ILVariable objVar, KnownTypeCode disposeType)
{
if (condition.MatchCompNotEquals(out var left, out var right))
{
if (!left.MatchLdLoc(objVar) || !right.MatchLdNull())
return false;
return true;
}
if (condition is MatchInstruction
{
CheckNotNull: true,
CheckType: true,
TestedOperand: LdLoc { Variable: var v },
Variable: var newObjVar
})
{
if (v != objVar)
return false;
if (!newObjVar.Type.IsKnownType(disposeType))
return false;
objVar = newObjVar;
return true;
}
return false;
}
/// <summary>
/// stloc test(resourceExpression)
/// .try BlockContainer {
@ -371,7 +430,9 @@ namespace ICSharpCode.Decompiler.IL.Transforms
/// </summary>
private bool TransformAsyncUsing(Block block, int i)
{
if (i < 1 || !context.Settings.AsyncUsingAndForEachStatement)
if (!context.Settings.AsyncUsingAndForEachStatement)
return false;
if (i < 1 || i >= block.Instructions.Count)
return false;
if (!(block.Instructions[i] is TryFinally tryFinally) || !(block.Instructions[i - 1] is StLoc storeInst))
return false;

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