From 503048b314a73bc222372c925feaa385d6832256 Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Sat, 23 Jul 2022 21:33:47 +0200
Subject: [PATCH] Prevent the early ILInlining pass from creating `addressof`
 instructions

---
 .../CSharp/CSharpDecompiler.cs                 |  2 +-
 .../IL/ControlFlow/AsyncAwaitDecompiler.cs     |  2 +-
 .../IL/Transforms/ILInlining.cs                | 18 +++++++++++-------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs b/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs
index 15cc274c7..c14b83010 100644
--- a/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs
+++ b/ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs
@@ -136,7 +136,7 @@ namespace ICSharpCode.Decompiler.CSharp
 							// run interleaved (statement by statement).
 							// Pretty much all transforms that open up new expression inlining
 							// opportunities belong in this category.
-							new ILInlining(),
+							new ILInlining() { options = InliningOptions.AllowInliningOfLdloca },
 							// Inlining must be first, because it doesn't trigger re-runs.
 							// Any other transform that opens up new inlining opportunities should call RequestRerun().
 							new ExpressionTransforms(),
diff --git a/ICSharpCode.Decompiler/IL/ControlFlow/AsyncAwaitDecompiler.cs b/ICSharpCode.Decompiler/IL/ControlFlow/AsyncAwaitDecompiler.cs
index c6b54ad44..67b687362 100644
--- a/ICSharpCode.Decompiler/IL/ControlFlow/AsyncAwaitDecompiler.cs
+++ b/ICSharpCode.Decompiler/IL/ControlFlow/AsyncAwaitDecompiler.cs
@@ -189,7 +189,7 @@ namespace ICSharpCode.Decompiler.IL.ControlFlow
 			foreach (var block in function.Descendants.OfType<Block>())
 			{
 				// Run inlining, but don't remove dead variables (they might get revived by TranslateFieldsToLocalAccess)
-				ILInlining.InlineAllInBlock(function, block, context);
+				ILInlining.InlineAllInBlock(function, block, InliningOptions.None, context);
 				if (IsAsyncEnumerator)
 				{
 					// Remove lone 'ldc.i4', those are sometimes left over after C# compiler
diff --git a/ICSharpCode.Decompiler/IL/Transforms/ILInlining.cs b/ICSharpCode.Decompiler/IL/Transforms/ILInlining.cs
index ecdb7d2b4..c7b262c88 100644
--- a/ICSharpCode.Decompiler/IL/Transforms/ILInlining.cs
+++ b/ICSharpCode.Decompiler/IL/Transforms/ILInlining.cs
@@ -34,6 +34,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 		IntroduceNamedArguments = 2,
 		FindDeconstruction = 4,
 		AllowChangingOrderOfEvaluationForExceptions = 8,
+		AllowInliningOfLdloca = 0x10
 	}
 
 	/// <summary>
@@ -41,23 +42,25 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 	/// </summary>
 	public class ILInlining : IILTransform, IBlockTransform, IStatementTransform
 	{
+		internal InliningOptions options;
+
 		public void Run(ILFunction function, ILTransformContext context)
 		{
 			foreach (var block in function.Descendants.OfType<Block>())
 			{
-				InlineAllInBlock(function, block, context);
+				InlineAllInBlock(function, block, this.options, context);
 			}
 			function.Variables.RemoveDead();
 		}
 
 		public void Run(Block block, BlockTransformContext context)
 		{
-			InlineAllInBlock(context.Function, block, context);
+			InlineAllInBlock(context.Function, block, this.options, context);
 		}
 
 		public void Run(Block block, int pos, StatementTransformContext context)
 		{
-			InlineOneIfPossible(block, pos, OptionsForBlock(block, pos, context), context: context);
+			InlineOneIfPossible(block, pos, this.options | OptionsForBlock(block, pos, context), context: context);
 		}
 
 		internal static InliningOptions OptionsForBlock(Block block, int pos, ILTransformContext context)
@@ -94,7 +97,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			}
 		}
 
-		public static bool InlineAllInBlock(ILFunction function, Block block, ILTransformContext context)
+		public static bool InlineAllInBlock(ILFunction function, Block block, InliningOptions options, ILTransformContext context)
 		{
 			bool modified = false;
 			var instructions = block.Instructions;
@@ -102,9 +105,6 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			{
 				if (instructions[i] is StLoc inst)
 				{
-					InliningOptions options = InliningOptions.None;
-					if (context.Settings.AggressiveInlining || IsCatchWhenBlock(block) || IsInConstructorInitializer(function, inst))
-						options = InliningOptions.Aggressive;
 					if (InlineOneIfPossible(block, i, options, context))
 					{
 						modified = true;
@@ -288,6 +288,10 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 		static bool IsGeneratedValueTypeTemporary(LdLoca loadInst, ILVariable v, ILInstruction inlinedExpression, InliningOptions options)
 		{
 			Debug.Assert(loadInst.Variable == v);
+			if (!options.HasFlag(InliningOptions.AllowInliningOfLdloca))
+			{
+				return false; // inlining of ldloca is not allowed in the early inlining stage
+			}
 			// Inlining a value type variable is allowed only if the resulting code will maintain the semantics
 			// that the method is operating on a copy.
 			// Thus, we have to ensure we're operating on an r-value.