Handle unreachable code

icsharpcode · Feb 20, 2011 · adfc7fc · adfc7fc
1 parent eda2073
commit adfc7fc
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Showing 3 changed files with 38 additions and 2 deletions.
diff --git a/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs b/ICSharpCode.Decompiler/Ast/AstMethodBodyBuilder.cs
@@ -160,6 +160,8 @@ IEnumerable<Statement> TransformNode(ILNode node)
 				yield return tryCatchStmt;
 			} else if (node is ILBlock) {
 				yield return TransformBlock((ILBlock)node);
+			} else if (node is ILComment) {
+				yield return new CommentStatement(((ILComment)node).Text).WithAnnotation(((ILComment)node).ILRanges);
 			} else {
 				throw new Exception("Unknown node type");
 			}

diff --git a/ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs b/ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs
@@ -57,7 +57,17 @@ public List<StackSlot> CloneStack(int? popCount)
 			public override string ToString()
 			{
 				StringBuilder sb = new StringBuilder();
-				sb.AppendFormat("{0}:{1} {2} {3}", this.Name, this.Label != null ? " *" : "", this.Code.GetName(), this.Operand);
+				sb.AppendFormat("{0}:{1} {2} ", this.Name, this.Label != null ? " *" : "", this.Code.GetName());
+				if (this.Operand is ILLabel) {
+					sb.Append(((ILLabel)this.Operand).Name);
+				} else if (this.Operand is ILLabel[]) {
+					foreach(ILLabel label in (ILLabel[])this.Operand) {
+						sb.Append(label.Name);
+						sb.Append(" ");
+					}
+				} else {
+					sb.Append(this.Operand.ToString());
+				}
 				if (this.StackBefore != null) {
 					sb.Append(" StackBefore = {");
 					bool first = true;
@@ -234,6 +244,9 @@ List<ByteCode> StackAnalysis(MethodDefinition methodDef)
 
 			// Genertate temporary variables to replace stack
 			foreach(ByteCode byteCode in body) {
+				if (byteCode.StackBefore == null)
+					continue;
+
 				int argIdx = 0;
 				int popCount = byteCode.PopCount ?? byteCode.StackBefore.Count;
 				for (int i = byteCode.StackBefore.Count - popCount; i < byteCode.StackBefore.Count; i++) {
@@ -395,8 +408,18 @@ List<ILNode> ConvertToAst(List<ByteCode> body)
 
 			// Convert stack-based IL code to ILAst tree
 			foreach(ByteCode byteCode in body) {
+				ILRange ilRange = new ILRange() { From = byteCode.Offset, To = byteCode.EndOffset };
+
+				if (byteCode.StackBefore == null) {
+					ast.Add(new ILComment() {
+						Text = "Unreachable code: " + byteCode.Code.GetName(),
+						ILRanges = new List<ILRange>(new[] { ilRange })
+					});
+					continue;
+				}
+
 				ILExpression expr = new ILExpression(byteCode.Code, byteCode.Operand);
-				expr.ILRanges.Add(new ILRange() { From = byteCode.Offset, To = byteCode.EndOffset });
+				expr.ILRanges.Add(ilRange);
 
 				// Label for this instruction
 				if (byteCode.Label != null) {

diff --git a/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs b/ICSharpCode.Decompiler/ILAst/ILAstTypes.cs
@@ -83,6 +83,17 @@ public override void WriteTo(ITextOutput output)
 		}
 	}
 
+	public class ILComment: ILNode
+	{
+		public string Text;
+		public List<ILRange> ILRanges { get; set; }
+
+		public override void WriteTo(ITextOutput output)
+		{
+			output.WriteLine("// " + this.Text);
+		}
+	}
+
 	public class ILTryCatchBlock: ILNode
 	{
 		public class CatchBlock: ILBlock