public static void Run(ILFunction function, ILTransformContext context)
{
if (!context.Settings.AwaitInCatchFinally)
{
return;
}
HashSet <BlockContainer> changedContainers = new HashSet <BlockContainer>();
HashSet <Block> removedBlocks = new HashSet <Block>();
// 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;
}
// Detect all handlers that contain an await expression
AnalyzeHandlers(tryCatch.Handlers, out var catchHandlerIdentifier, out var transformableCatchBlocks);
var cfg = new ControlFlowGraph(container, context.CancellationToken);
if (transformableCatchBlocks.Count > 0)
{
changedContainers.Add(container);
}
SwitchInstruction switchInstructionOpt = null;
foreach (var result in transformableCatchBlocks)
{
removedBlocks.Clear();
var node = cfg.GetNode(result.RealCatchBlockEntryPoint);
context.StepStartGroup($"Inline catch block with await (at {result.Handler.Variable.Name})", result.Handler);
// Remove the IfInstruction from the jump table and eliminate all branches to the block.
switch (result.JumpTableEntry)
{
case IfInstruction jumpTableEntry:
var jumpTableBlock = (Block)jumpTableEntry.Parent;
context.Step("Remove jump-table entry", result.JumpTableEntry);
jumpTableBlock.Instructions.RemoveAt(result.JumpTableEntry.ChildIndex);
foreach (var branch in tryCatch.Descendants.OfType <Branch>())
{
if (branch.TargetBlock == jumpTableBlock)
{
if (result.NextBlockOrExitContainer is BlockContainer exitContainer)
{
context.Step("branch jumpTableBlock => leave exitContainer", branch);
branch.ReplaceWith(new Leave(exitContainer));
}
else
{
context.Step("branch jumpTableBlock => branch nextBlock", branch);
branch.ReplaceWith(new Branch((Block)result.NextBlockOrExitContainer));
}
}
}
break;
case SwitchSection jumpTableEntry:
Debug.Assert(switchInstructionOpt == null || jumpTableEntry.Parent == switchInstructionOpt);
switchInstructionOpt = (SwitchInstruction)jumpTableEntry.Parent;
break;
}
// Add the real catch block entry-point to the block container
var catchBlockHead = ((BlockContainer)result.Handler.Body).Blocks.Last();
result.RealCatchBlockEntryPoint.Remove();
((BlockContainer)result.Handler.Body).Blocks.Insert(0, result.RealCatchBlockEntryPoint);
// Remove the generated catch block
catchBlockHead.Remove();
TransformAsyncThrowToThrow(context, removedBlocks, result.RealCatchBlockEntryPoint);
// Inline all blocks that are dominated by the entrypoint of the real catch block
foreach (var n in cfg.cfg)
{
Block block = (Block)n.UserData;
if (node.Dominates(n))
{
TransformAsyncThrowToThrow(context, removedBlocks, block);
if (block.Parent == result.Handler.Body)
{
continue;
}
if (!removedBlocks.Contains(block))
{
context.Step("Move block", result.Handler.Body);
MoveBlock(block, (BlockContainer)result.Handler.Body);
}
}
}
// Remove unreachable pattern blocks
// TODO : sanity check
if (result.NextBlockOrExitContainer is Block nextBlock && nextBlock.IncomingEdgeCount == 0)
{
List <Block> dependentBlocks = new List <Block>();
Block current = nextBlock;
do
{
foreach (var branch in current.Descendants.OfType <Branch>())
{
dependentBlocks.Add(branch.TargetBlock);
}
current.Remove();
dependentBlocks.Remove(current);
current = dependentBlocks.FirstOrDefault(b => b.IncomingEdgeCount == 0);
} while (current != null);
}
// Remove all assignments to the common object variable that stores the exception object.
if (result.ObjectVariable != result.Handler.Variable)
{
foreach (var load in result.ObjectVariable.LoadInstructions.ToArray())
{
if (!load.IsDescendantOf(result.Handler))
{
continue;
}
if (load.Parent is CastClass cc && cc.Type.Equals(result.Handler.Variable.Type))
{
cc.ReplaceWith(new LdLoc(result.Handler.Variable).WithILRange(cc).WithILRange(load));
}
else
{
load.ReplaceWith(new LdLoc(result.Handler.Variable).WithILRange(load));
}
}
}
context.StepEndGroup(keepIfEmpty: true);
}
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;
}
// Detect all handlers that contain an await expression
AnalyzeHandlers(tryCatch.Handlers, out var catchHandlerIdentifier, out var transformableCatchBlocks);
var cfg = new ControlFlowGraph(container, context.CancellationToken);
if (transformableCatchBlocks.Count > 0)
{
changedContainers.Add(container);
}
foreach (var result in transformableCatchBlocks)
{
var node = cfg.GetNode(result.RealCatchBlockEntryPoint);
context.Step("Inline catch block with await", result.Handler);
// Remove the IfInstruction from the jump table and eliminate all branches to the block.
var jumpTableBlock = (Block)result.JumpTableEntry.Parent;
jumpTableBlock.Instructions.RemoveAt(result.JumpTableEntry.ChildIndex);
foreach (var branch in tryCatch.Descendants.OfType <Branch>())
{
if (branch.TargetBlock == jumpTableBlock)
{
if (result.NextBlockOrExitContainer is BlockContainer exitContainer)
{
branch.ReplaceWith(new Leave(exitContainer));
}
else
{
branch.ReplaceWith(new Branch((Block)result.NextBlockOrExitContainer));
}
}
}
// Add the real catch block entry-point to the block container
var catchBlockHead = ((BlockContainer)result.Handler.Body).Blocks.Last();
result.RealCatchBlockEntryPoint.Remove();
((BlockContainer)result.Handler.Body).Blocks.Insert(0, result.RealCatchBlockEntryPoint);
// Remove the generated catch block
catchBlockHead.Remove();
// Inline all blocks that are dominated by the entrypoint of the real catch block
foreach (var n in cfg.cfg)
{
if (((Block)n.UserData).Parent == result.Handler.Body)
{
continue;
}
if (node.Dominates(n))
{
MoveBlock((Block)n.UserData, (BlockContainer)result.Handler.Body);
}
}
// Remove all assignments to the common object variable that stores the exception object.
if (result.ObjectVariableStore != null)
{
foreach (var load in result.ObjectVariableStore.Variable.LoadInstructions.ToArray())
{
if (load.Parent is CastClass cc && cc.Type == result.Handler.Variable.Type)
{
cc.ReplaceWith(new LdLoc(result.Handler.Variable));
}
else
{
load.ReplaceWith(new LdLoc(result.Handler.Variable));
}
}
}
}
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);
}
}