Move LocalFunctionDecompiler.GetStatement to Block.GetContainingStatement

Author: siegfriedpammer

ICSharpCode.Decompiler/IL/ControlFlow/AwaitInFinallyTransform.cs

@@ -16,12 +16,10 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 
-using ICSharpCode.Decompiler.FlowAnalysis;
 using ICSharpCode.Decompiler.IL.Transforms;
 using ICSharpCode.Decompiler.TypeSystem;
 
@@ -109,7 +107,7 @@ public static void Run(ILFunction function, ILTransformContext context)
 				if (objectVariable.LoadCount != 1 || objectVariable.StoreCount > 2)
 					continue;
 
-				var beforeExceptionCaptureBlock = (Block)LocalFunctionDecompiler.GetStatement(objectVariable.LoadInstructions[0])?.Parent;
+				var beforeExceptionCaptureBlock = Block.FindClosestBlock(objectVariable.LoadInstructions[0]);
 				if (beforeExceptionCaptureBlock == null)
 					continue;
 

ICSharpCode.Decompiler/IL/Instructions/Block.cs

@@ -383,6 +383,22 @@ public void RunTransforms(IEnumerable<IBlockTransform> transforms, BlockTransfor
 			return null;
 		}
 
+		/// <summary>
+		/// Gets the closest ancestor that is child of a control-flow (top-level) Block.
+		/// Returns null, if the instruction is not a descendant of a Block.
+		/// </summary>
+		public static ILInstruction? GetContainingStatement(ILInstruction inst)
+		{
+			var curr = inst;
+			while (curr != null)
+			{
+				if (curr.Parent is Block { Kind: BlockKind.ControlFlow })
+					return curr;
+				curr = curr.Parent;
+			}
+			return null;
+		}
+
 		public bool MatchInlineAssignBlock([NotNullWhen(true)] out CallInstruction? call, [NotNullWhen(true)] out ILInstruction? value)
 		{
 			call = null;

ICSharpCode.Decompiler/IL/Transforms/DetectCatchWhenConditionBlocks.cs

@@ -16,9 +16,6 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
 using System.Linq;
 
 using ICSharpCode.Decompiler.TypeSystem;
@@ -107,7 +104,7 @@ static void PropagateExceptionVariable(ILTransformContext context, TryCatchHandl
 
 				// We are only interested in store "statements" copying the exception variable
 				// without modifying it.
-				var statement = LocalFunctionDecompiler.GetStatement(load);
+				var statement = Block.GetContainingStatement(load);
 				if (!(statement is StLoc stloc))
 				{
 					i++;

ICSharpCode.Decompiler/IL/Transforms/ExpressionTransforms.cs

@@ -312,25 +312,14 @@ protected internal override void VisitCallVirt(CallVirt inst)
 
 		protected internal override void VisitNewObj(NewObj inst)
 		{
-			Block block;
 			if (TransformSpanTCtorContainingStackAlloc(inst, out ILInstruction locallocSpan))
 			{
 				context.Step("new Span<T>(stackalloc) -> stackalloc Span<T>", inst);
 				inst.ReplaceWith(locallocSpan);
-				block = null;
-				ILInstruction stmt = locallocSpan;
-				while (stmt.Parent != null)
-				{
-					if (stmt.Parent is Block b)
-					{
-						block = b;
-						break;
-					}
-					stmt = stmt.Parent;
-				}
+				ILInstruction stmt = Block.GetContainingStatement(locallocSpan);
 				// Special case to eliminate extra store
 				if (stmt.GetNextSibling() is StLoc storeStmt && storeStmt.Value is LdLoc)
-					ILInlining.InlineIfPossible(block, stmt.ChildIndex, context);
+					ILInlining.InlineIfPossible((Block)stmt.Parent, stmt.ChildIndex, context);
 				return;
 			}
 			if (TransformArrayInitializers.TransformSpanTArrayInitialization(inst, context, out var replacement))

ICSharpCode.Decompiler/IL/Transforms/LocalFunctionDecompiler.cs

@@ -575,17 +575,6 @@ internal static bool IsClosureParameter(IParameter parameter, ITypeResolveContex
 				&& TransformDisplayClassUsage.IsPotentialClosure(context.CurrentTypeDefinition, type);
 		}
 
-		internal static ILInstruction GetStatement(ILInstruction inst)
-		{
-			while (inst.Parent != null)
-			{
-				if (inst.Parent is Block b && b.Kind == BlockKind.ControlFlow)
-					return inst;
-				inst = inst.Parent;
-			}
-			return inst;
-		}
-
 		LocalFunctionMethod ReduceToLocalFunction(IMethod method, int typeParametersToRemove)
 		{
 			int parametersToRemove = 0;
@@ -747,7 +736,7 @@ ILInstruction GetClosureInitializer(ILVariable variable)
 				if (variable.Kind == VariableKind.Parameter)
 					return null;
 				if (type.Kind == TypeKind.Struct)
-					return GetStatement(variable.AddressInstructions.OrderBy(i => i.StartILOffset).First());
+					return Block.GetContainingStatement(variable.AddressInstructions.OrderBy(i => i.StartILOffset).First());
 				else
 					return (StLoc)variable.StoreInstructions[0];
 			}

ICSharpCode.Decompiler/IL/Transforms/TransformDisplayClassUsage.cs

@@ -604,7 +604,7 @@ internal static bool IsClosure(ILTransformContext context, ILVariable variable,
 			if (context.Settings.LocalFunctions && closureType?.Kind == TypeKind.Struct
 				&& variable.UsesInitialValue && IsPotentialClosure(context, closureType))
 			{
-				initializer = LocalFunctionDecompiler.GetStatement(variable.AddressInstructions.OrderBy(i => i.StartILOffset).First());
+				initializer = Block.GetContainingStatement(variable.AddressInstructions.OrderBy(i => i.StartILOffset).First());
 				return true;
 			}
 			return false;