From e03576ea2e3d94f55417472aa5d1fc19bacfdf05 Mon Sep 17 00:00:00 2001
From: Andrew Au <andrewau@microsoft.com>
Date: Tue, 28 Jul 2020 11:34:00 -0700
Subject: [PATCH] Fix unwind info decoding

---
 .../Amd64/UnwindInfo.cs                       | 25 +++++++++++++------
 src/coreclr/src/tools/r2rdump/TextDumper.cs   | 13 ++++------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/coreclr/src/tools/aot/ILCompiler.Reflection.ReadyToRun/Amd64/UnwindInfo.cs b/src/coreclr/src/tools/aot/ILCompiler.Reflection.ReadyToRun/Amd64/UnwindInfo.cs
index 1c5150bcedaf6d..08241e0a433d11 100644
--- a/src/coreclr/src/tools/aot/ILCompiler.Reflection.ReadyToRun/Amd64/UnwindInfo.cs
+++ b/src/coreclr/src/tools/aot/ILCompiler.Reflection.ReadyToRun/Amd64/UnwindInfo.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Text;
 
 namespace ILCompiler.Reflection.ReadyToRun.Amd64
@@ -76,6 +77,19 @@ public UnwindCode(byte[] image, int index, ref int offset)
             FrameOffset = NativeReader.ReadUInt16(image, ref offset);
             NextFrameOffset = -1;
 
+            if (UnwindOp == UnwindOpCodes.UWOP_ALLOC_LARGE)
+            {
+                uint codedSize;
+                if (OpInfo == 0)
+                {
+                    codedSize = NativeReader.ReadUInt16(image, ref offset);
+                }
+                else if (OpInfo == 1)
+                {
+                    codedSize = NativeReader.ReadUInt32(image, ref offset);
+                }
+            }
+
             IsOpInfo = false;
         }
     }
@@ -95,7 +109,7 @@ public class UnwindInfo : BaseUnwindInfo
         public Registers FrameRegister { get; set; } //4 bits
         public byte FrameOffset { get; set; } //4 bits
         public UnwindCode[] UnwindCodeArray { get; set; }
-        public Dictionary<int, List<UnwindCode>> UnwindCodes { get; set; }
+        public Dictionary<int, UnwindCode> UnwindCodes { get; set; }
         public uint PersonalityRoutineRVA { get; set; }
 
         public UnwindInfo() { }
@@ -115,7 +129,7 @@ public UnwindInfo(byte[] image, int offset)
             FrameOffset = (byte)(frameRegisterAndOffset >> 4);
 
             UnwindCodeArray = new UnwindCode[CountOfUnwindCodes];
-            UnwindCodes = new Dictionary<int, List<UnwindCode>>();
+            UnwindCodes = new Dictionary<int, UnwindCode>();
             for (int i = 0; i < CountOfUnwindCodes; i++)
             {
                 UnwindCodeArray[i] = new UnwindCode(image, i, ref offset);
@@ -123,11 +137,8 @@ public UnwindInfo(byte[] image, int offset)
             for (int i = 0; i < CountOfUnwindCodes; i++)
             {
                 ParseUnwindCode(ref i);
-                if (!UnwindCodes.ContainsKey(UnwindCodeArray[i].CodeOffset))
-                {
-                    UnwindCodes[UnwindCodeArray[i].CodeOffset] = new List<UnwindCode>();
-                }
-                UnwindCodes[UnwindCodeArray[i].CodeOffset].Add(UnwindCodeArray[i]);
+                Debug.Assert(!UnwindCodes.ContainsKey(UnwindCodeArray[i].CodeOffset));
+                UnwindCodes.Add(UnwindCodeArray[i].CodeOffset, UnwindCodeArray[i]);
             }
 
             Size = _offsetofUnwindCode + CountOfUnwindCodes * _sizeofUnwindCode;
diff --git a/src/coreclr/src/tools/r2rdump/TextDumper.cs b/src/coreclr/src/tools/r2rdump/TextDumper.cs
index b3bf91845f380d..19aa23f791eae5 100644
--- a/src/coreclr/src/tools/r2rdump/TextDumper.cs
+++ b/src/coreclr/src/tools/r2rdump/TextDumper.cs
@@ -217,16 +217,13 @@ internal override void DumpDisasm(RuntimeFunction rtf, int imageOffset)
 
                 if (_r2r.Machine == Machine.Amd64 && ((ILCompiler.Reflection.ReadyToRun.Amd64.UnwindInfo)rtf.UnwindInfo).UnwindCodes.ContainsKey(codeOffset))
                 {
-                    List<ILCompiler.Reflection.ReadyToRun.Amd64.UnwindCode> codes = ((ILCompiler.Reflection.ReadyToRun.Amd64.UnwindInfo)rtf.UnwindInfo).UnwindCodes[codeOffset];
-                    foreach (ILCompiler.Reflection.ReadyToRun.Amd64.UnwindCode code in codes)
+                    ILCompiler.Reflection.ReadyToRun.Amd64.UnwindCode code = ((ILCompiler.Reflection.ReadyToRun.Amd64.UnwindInfo)rtf.UnwindInfo).UnwindCodes[codeOffset];                    
+                    _writer.Write($"{indentString}{code.UnwindOp} {code.OpInfoStr}");
+                    if (code.NextFrameOffset != -1)
                     {
-                        _writer.Write($"{indentString}{code.UnwindOp} {code.OpInfoStr}");
-                        if (code.NextFrameOffset != -1)
-                        {
-                            _writer.WriteLine($"{indentString}{code.NextFrameOffset}");
-                        }
-                        _writer.WriteLine();
+                        _writer.WriteLine($"{indentString}{code.NextFrameOffset}");
                     }
+                    _writer.WriteLine();
                 }
 
                 if (!_options.HideTransitions && rtf.Method.GcInfo?.Transitions != null && rtf.Method.GcInfo.Transitions.TryGetValue(codeOffset, out List<BaseGcTransition> transitionsForOffset))