mirror of https://github.com/icsharpcode/ILSpy.git
242 lines
9.9 KiB
242 lines
9.9 KiB
// Copyright (c) 2018 Siegfried Pammer |
|
// |
|
// Permission is hereby granted, free of charge, to any person obtaining a copy of this |
|
// software and associated documentation files (the "Software"), to deal in the Software |
|
// without restriction, including without limitation the rights to use, copy, modify, merge, |
|
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons |
|
// to whom the Software is furnished to do so, subject to the following conditions: |
|
// |
|
// The above copyright notice and this permission notice shall be included in all copies or |
|
// substantial portions of the Software. |
|
// |
|
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, |
|
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR |
|
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE |
|
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
|
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
|
// DEALINGS IN THE SOFTWARE. |
|
|
|
using System.Collections.Generic; |
|
using System.Linq; |
|
using ICSharpCode.Decompiler.FlowAnalysis; |
|
using ICSharpCode.Decompiler.IL.Transforms; |
|
using ICSharpCode.Decompiler.TypeSystem; |
|
|
|
namespace ICSharpCode.Decompiler.IL.ControlFlow |
|
{ |
|
class AwaitInFinallyTransform |
|
{ |
|
public static void Run(ILFunction function, ILTransformContext context) |
|
{ |
|
if (!context.Settings.AwaitInCatchFinally) |
|
return; |
|
HashSet<BlockContainer> changedContainers = new HashSet<BlockContainer>(); |
|
|
|
// analyze all try-catch statements in the function |
|
foreach (var tryCatch in function.Descendants.OfType<TryCatch>().ToArray()) { |
|
if (!(tryCatch.Parent?.Parent is BlockContainer container)) |
|
continue; |
|
// await in finally uses a single catch block with catch-type object |
|
if (tryCatch.Handlers.Count != 1 || !(tryCatch.Handlers[0].Body is BlockContainer catchBlockContainer) || !tryCatch.Handlers[0].Variable.Type.IsKnownType(KnownTypeCode.Object)) |
|
continue; |
|
// and consists of an assignment to a temporary that is used outside the catch block |
|
// and a jump to the finally block |
|
var block = catchBlockContainer.EntryPoint; |
|
if (block.Instructions.Count < 2 || !block.Instructions[0].MatchStLoc(out var globalCopyVar, out var value) || !value.MatchLdLoc(tryCatch.Handlers[0].Variable)) |
|
continue; |
|
if (block.Instructions.Count == 3) { |
|
if (!block.Instructions[1].MatchStLoc(out var globalCopyVarTemp, out value) || !value.MatchLdLoc(globalCopyVar)) |
|
continue; |
|
globalCopyVar = globalCopyVarTemp; |
|
} |
|
if (!block.Instructions[block.Instructions.Count - 1].MatchBranch(out var entryPointOfFinally)) |
|
continue; |
|
// globalCopyVar should only be used once, at the end of the finally-block |
|
if (globalCopyVar.LoadCount != 1 || globalCopyVar.StoreCount > 2) |
|
continue; |
|
var tempStore = globalCopyVar.LoadInstructions[0].Parent as StLoc; |
|
if (tempStore == null || !MatchExceptionCaptureBlock(tempStore, out var exitOfFinally, out var afterFinally, out var blocksToRemove)) |
|
continue; |
|
if (!MatchAfterFinallyBlock(ref afterFinally, blocksToRemove, out bool removeFirstInstructionInAfterFinally)) |
|
continue; |
|
var cfg = new ControlFlowGraph(container, context.CancellationToken); |
|
var exitOfFinallyNode = cfg.GetNode(exitOfFinally); |
|
var entryPointOfFinallyNode = cfg.GetNode(entryPointOfFinally); |
|
|
|
var additionalBlocksInFinally = new HashSet<Block>(); |
|
var invalidExits = new List<ControlFlowNode>(); |
|
|
|
TraverseDominatorTree(entryPointOfFinallyNode); |
|
|
|
void TraverseDominatorTree(ControlFlowNode node) |
|
{ |
|
if (entryPointOfFinallyNode != node) { |
|
if (entryPointOfFinallyNode.Dominates(node)) |
|
additionalBlocksInFinally.Add((Block)node.UserData); |
|
else |
|
invalidExits.Add(node); |
|
} |
|
|
|
if (node == exitOfFinallyNode) |
|
return; |
|
|
|
foreach (var child in node.DominatorTreeChildren) { |
|
TraverseDominatorTree(child); |
|
} |
|
} |
|
|
|
if (invalidExits.Any()) |
|
continue; |
|
|
|
context.Step("Inline finally block with await", tryCatch.Handlers[0]); |
|
|
|
foreach (var blockToRemove in blocksToRemove) { |
|
blockToRemove.Remove(); |
|
} |
|
var finallyContainer = new BlockContainer(); |
|
entryPointOfFinally.Remove(); |
|
if (removeFirstInstructionInAfterFinally) |
|
afterFinally.Instructions.RemoveAt(0); |
|
changedContainers.Add(container); |
|
var outer = BlockContainer.FindClosestContainer(container.Parent); |
|
if (outer != null) changedContainers.Add(outer); |
|
finallyContainer.Blocks.Add(entryPointOfFinally); |
|
finallyContainer.AddILRange(entryPointOfFinally); |
|
exitOfFinally.Instructions.RemoveRange(tempStore.ChildIndex, 3); |
|
exitOfFinally.Instructions.Add(new Leave(finallyContainer)); |
|
foreach (var branchToFinally in container.Descendants.OfType<Branch>()) { |
|
if (branchToFinally.TargetBlock == entryPointOfFinally) |
|
branchToFinally.ReplaceWith(new Branch(afterFinally)); |
|
} |
|
foreach (var newBlock in additionalBlocksInFinally) { |
|
newBlock.Remove(); |
|
finallyContainer.Blocks.Add(newBlock); |
|
finallyContainer.AddILRange(newBlock); |
|
} |
|
tryCatch.ReplaceWith(new TryFinally(tryCatch.TryBlock, finallyContainer).WithILRange(tryCatch.TryBlock)); |
|
} |
|
|
|
// clean up all modified containers |
|
foreach (var container in changedContainers) |
|
container.SortBlocks(deleteUnreachableBlocks: true); |
|
} |
|
|
|
/// <summary> |
|
/// Block finallyHead (incoming: 2) { |
|
/// [body of finally] |
|
/// stloc V_4(ldloc V_1) |
|
/// if (comp(ldloc V_4 == ldnull)) br afterFinally |
|
/// br typeCheckBlock |
|
/// } |
|
/// |
|
/// Block typeCheckBlock (incoming: 1) { |
|
/// stloc S_110(isinst System.Exception(ldloc V_4)) |
|
/// if (comp(ldloc S_110 != ldnull)) br captureBlock |
|
/// br throwBlock |
|
/// } |
|
/// |
|
/// Block throwBlock (incoming: 1) { |
|
/// throw(ldloc V_4) |
|
/// } |
|
/// |
|
/// Block captureBlock (incoming: 1) { |
|
/// callvirt Throw(call Capture(ldloc S_110)) |
|
/// br afterFinally |
|
/// } |
|
/// |
|
/// Block afterFinally (incoming: 2) { |
|
/// stloc V_1(ldnull) |
|
/// [after finally] |
|
/// } |
|
/// </summary> |
|
static bool MatchExceptionCaptureBlock(StLoc tempStore, out Block endOfFinally, out Block afterFinally, out List<Block> blocksToRemove) |
|
{ |
|
afterFinally = null; |
|
endOfFinally = (Block)tempStore.Parent; |
|
blocksToRemove = new List<Block>(); |
|
int count = endOfFinally.Instructions.Count; |
|
if (tempStore.ChildIndex != count - 3) |
|
return false; |
|
if (!(endOfFinally.Instructions[count - 2] is IfInstruction ifInst)) |
|
return false; |
|
if (!endOfFinally.Instructions.Last().MatchBranch(out var typeCheckBlock)) |
|
return false; |
|
if (!ifInst.TrueInst.MatchBranch(out afterFinally)) |
|
return false; |
|
// match typeCheckBlock |
|
if (typeCheckBlock.Instructions.Count != 3) |
|
return false; |
|
if (!typeCheckBlock.Instructions[0].MatchStLoc(out var castStore, out var cast) |
|
|| !cast.MatchIsInst(out var arg, out var type) || !type.IsKnownType(KnownTypeCode.Exception) || !arg.MatchLdLoc(tempStore.Variable)) |
|
return false; |
|
if (!typeCheckBlock.Instructions[1].MatchIfInstruction(out var cond, out var jumpToCaptureBlock)) |
|
return false; |
|
if (!cond.MatchCompNotEqualsNull(out arg) || !arg.MatchLdLoc(castStore)) |
|
return false; |
|
if (!typeCheckBlock.Instructions[2].MatchBranch(out var throwBlock)) |
|
return false; |
|
if (!jumpToCaptureBlock.MatchBranch(out var captureBlock)) |
|
return false; |
|
// match throwBlock |
|
if (throwBlock.Instructions.Count != 1 || !throwBlock.Instructions[0].MatchThrow(out arg) || !arg.MatchLdLoc(tempStore.Variable)) |
|
return false; |
|
// match captureBlock |
|
if (captureBlock.Instructions.Count != 2) |
|
return false; |
|
if (!captureBlock.Instructions[1].MatchBranch(afterFinally)) |
|
return false; |
|
if (!(captureBlock.Instructions[0] is CallVirt callVirt) || callVirt.Method.FullName != "System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw" || callVirt.Arguments.Count != 1) |
|
return false; |
|
if (!(callVirt.Arguments[0] is Call call) || call.Method.FullName != "System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture" || call.Arguments.Count != 1) |
|
return false; |
|
if (!call.Arguments[0].MatchLdLoc(castStore)) |
|
return false; |
|
blocksToRemove.Add(typeCheckBlock); |
|
blocksToRemove.Add(throwBlock); |
|
blocksToRemove.Add(captureBlock); |
|
return true; |
|
} |
|
|
|
static bool MatchAfterFinallyBlock(ref Block afterFinally, List<Block> blocksToRemove, out bool removeFirstInstructionInAfterFinally) |
|
{ |
|
removeFirstInstructionInAfterFinally = false; |
|
if (afterFinally.Instructions.Count < 2) |
|
return false; |
|
ILVariable globalCopyVarSplitted; |
|
switch (afterFinally.Instructions[0]) { |
|
case IfInstruction ifInst: |
|
if (ifInst.Condition.MatchCompEquals(out var load, out var ldone) && ldone.MatchLdcI4(1) && load.MatchLdLoc(out var variable)) { |
|
if (!ifInst.TrueInst.MatchBranch(out var targetBlock)) |
|
return false; |
|
blocksToRemove.Add(afterFinally); |
|
afterFinally = targetBlock; |
|
return true; |
|
} else if (ifInst.Condition.MatchCompNotEquals(out load, out ldone) && ldone.MatchLdcI4(1) && load.MatchLdLoc(out variable)) { |
|
if (!afterFinally.Instructions[1].MatchBranch(out var targetBlock)) |
|
return false; |
|
blocksToRemove.Add(afterFinally); |
|
afterFinally = targetBlock; |
|
return true; |
|
} |
|
return false; |
|
case LdLoc ldLoc: |
|
if (ldLoc.Variable.LoadCount != 1 || ldLoc.Variable.StoreCount != 1) |
|
return false; |
|
if (!afterFinally.Instructions[1].MatchStLoc(out globalCopyVarSplitted, out var ldnull) || !ldnull.MatchLdNull()) |
|
return false; |
|
removeFirstInstructionInAfterFinally = true; |
|
break; |
|
case StLoc stloc: |
|
globalCopyVarSplitted = stloc.Variable; |
|
if (!stloc.Value.MatchLdNull()) |
|
return false; |
|
break; |
|
default: |
|
return false; |
|
} |
|
if (globalCopyVarSplitted.StoreCount != 1 || globalCopyVarSplitted.LoadCount != 0) |
|
return false; |
|
return true; |
|
} |
|
} |
|
}
|
|
|