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refacotors try/catch/finally handling to be able to more easily handl…
…e emission of code in try/finally blocks the initial motication was to avoid code duplication in foreach handling (#235)
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Cecilifier.Core/AST/StatementVisitor.TryCatchFinally.cs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,121 @@ | ||
| using System; | ||
| using System.Collections.Generic; | ||
| using Cecilifier.Core.Variables; | ||
| using Microsoft.CodeAnalysis.CSharp; | ||
| using Microsoft.CodeAnalysis.CSharp.Syntax; | ||
| using Mono.Cecil.Cil; | ||
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| namespace Cecilifier.Core.AST | ||
| { | ||
| internal partial class StatementVisitor | ||
| { | ||
| private void ProcessTryCatchFinallyBlock(string ilVar, CSharpSyntaxNode tryStatement, CatchClauseSyntax[] catches, Action<string> finallyBlockHandler) | ||
| { | ||
| ProcessWithInTryCatchFinallyBlock(ilVar, () => tryStatement.Accept(this), catches, finallyBlockHandler); | ||
| } | ||
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| protected void ProcessWithInTryCatchFinallyBlock(string ilVar, Action toProcess, CatchClauseSyntax[] catches, Action<string> finallyBlockHandler) | ||
| { | ||
| var exceptionHandlerTable = new ExceptionHandlerEntry[catches.Length + (finallyBlockHandler != null ? 1 : 0)]; | ||
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| var tryStartVar = AddCilInstructionWithLocalVariable(ilVar, OpCodes.Nop); | ||
| exceptionHandlerTable[0].TryStart = tryStartVar; | ||
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| toProcess(); | ||
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| var firstInstructionAfterTryCatchBlock = CreateCilInstruction(ilVar, OpCodes.Nop); | ||
| exceptionHandlerTable[^1].HandlerEnd = firstInstructionAfterTryCatchBlock; // sets up last handler end instruction | ||
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| Context.EmitCilInstruction(ilVar, OpCodes.Leave, firstInstructionAfterTryCatchBlock); | ||
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| for (var i = 0; i < catches.Length; i++) | ||
| { | ||
| HandleCatchClause(ilVar, catches[i], exceptionHandlerTable, i, firstInstructionAfterTryCatchBlock); | ||
| } | ||
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| HandleFinallyClause(ilVar, finallyBlockHandler, exceptionHandlerTable); | ||
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| AddCecilExpression($"{ilVar}.Append({firstInstructionAfterTryCatchBlock});"); | ||
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| WriteExceptionHandlers(exceptionHandlerTable); | ||
| } | ||
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| private void WriteExceptionHandlers(IEnumerable<ExceptionHandlerEntry> exceptionHandlerTable) | ||
| { | ||
| string methodVar = Context.DefinitionVariables.GetLastOf(VariableMemberKind.Method); | ||
| foreach (var handlerEntry in exceptionHandlerTable) | ||
| { | ||
| AddCecilExpression($"{methodVar}.Body.ExceptionHandlers.Add(new ExceptionHandler(ExceptionHandlerType.{handlerEntry.Kind})"); | ||
| AddCecilExpression("{"); | ||
| if (handlerEntry.Kind == ExceptionHandlerType.Catch) | ||
| { | ||
| AddCecilExpression($" CatchType = {handlerEntry.CatchType},"); | ||
| } | ||
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| AddCecilExpression($" TryStart = {handlerEntry.TryStart},"); | ||
| AddCecilExpression($" TryEnd = {handlerEntry.TryEnd},"); | ||
| AddCecilExpression($" HandlerStart = {handlerEntry.HandlerStart},"); | ||
| AddCecilExpression($" HandlerEnd = {handlerEntry.HandlerEnd}"); | ||
| AddCecilExpression("});"); | ||
| } | ||
| } | ||
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| private void HandleCatchClause(string ilVar, CatchClauseSyntax node, ExceptionHandlerEntry[] exceptionHandlerTable, int currentIndex, string firstInstructionAfterTryCatchBlock) | ||
| { | ||
| exceptionHandlerTable[currentIndex].Kind = ExceptionHandlerType.Catch; | ||
| exceptionHandlerTable[currentIndex].HandlerStart = AddCilInstructionWithLocalVariable(ilVar, OpCodes.Pop); // pops the exception object from stack... | ||
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| if (currentIndex == 0) | ||
| { | ||
| // The last instruction of the try block is the first instruction of the first catch block | ||
| exceptionHandlerTable[0].TryEnd = exceptionHandlerTable[currentIndex].HandlerStart; | ||
| } | ||
| else | ||
| { | ||
| exceptionHandlerTable[currentIndex - 1].HandlerEnd = exceptionHandlerTable[currentIndex].HandlerStart; | ||
| } | ||
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| exceptionHandlerTable[currentIndex].TryStart = exceptionHandlerTable[0].TryStart; | ||
| exceptionHandlerTable[currentIndex].TryEnd = exceptionHandlerTable[0].TryEnd; | ||
| exceptionHandlerTable[currentIndex].CatchType = ResolveType(node.Declaration.Type); | ||
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| VisitCatchClause(node); | ||
| Context.EmitCilInstruction(ilVar, OpCodes.Leave, firstInstructionAfterTryCatchBlock); | ||
| } | ||
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| private void HandleFinallyClause(string ilVar, Action<string> finallyBlockHandler, ExceptionHandlerEntry[] exceptionHandlerTable) | ||
| { | ||
| if (finallyBlockHandler == null) | ||
| return; | ||
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| var finallyEntryIndex = exceptionHandlerTable.Length - 1; | ||
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| exceptionHandlerTable[finallyEntryIndex].TryStart = exceptionHandlerTable[0].TryStart; | ||
| exceptionHandlerTable[finallyEntryIndex].TryEnd = exceptionHandlerTable[0].TryEnd; | ||
| exceptionHandlerTable[finallyEntryIndex].Kind = ExceptionHandlerType.Finally; | ||
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| var finallyStartVar = AddCilInstructionWithLocalVariable(ilVar, OpCodes.Nop); | ||
| exceptionHandlerTable[finallyEntryIndex].HandlerStart = finallyStartVar; | ||
| exceptionHandlerTable[finallyEntryIndex].TryEnd = finallyStartVar; | ||
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| if (finallyEntryIndex != 0) | ||
| { | ||
| // We have one or more catch blocks... set the end of the last catch block as the first instruction of the *finally* | ||
| exceptionHandlerTable[finallyEntryIndex - 1].HandlerEnd = finallyStartVar; | ||
| } | ||
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| finallyBlockHandler(exceptionHandlerTable[finallyEntryIndex].HandlerEnd); | ||
| Context.EmitCilInstruction(ilVar, OpCodes.Endfinally); | ||
| } | ||
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| private struct ExceptionHandlerEntry | ||
| { | ||
| public ExceptionHandlerType Kind; | ||
| public string CatchType; | ||
| public string TryStart; | ||
| public string TryEnd; | ||
| public string HandlerStart; | ||
| public string HandlerEnd; | ||
| } | ||
| } | ||
| } |
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