From 798a4edc1eaeeb7f65358893458ad0f2067a6c11 Mon Sep 17 00:00:00 2001
From: Washi <washi1337@protonmail.com>
Date: Sat, 9 Nov 2024 23:22:28 +0100
Subject: [PATCH] BUGFIX: Add EmptyDebugDataSegment

---
 .../Debug/Builder/DebugDirectoryBuffer.cs     |  2 +-
 .../Debug/EmptyDebugDataSegment.cs            | 43 +++++++++++++++++++
 .../Debug/SerializedDebugDataEntry.cs         |  3 ++
 3 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 src/AsmResolver.PE/Debug/EmptyDebugDataSegment.cs

diff --git a/src/AsmResolver.PE/Debug/Builder/DebugDirectoryBuffer.cs b/src/AsmResolver.PE/Debug/Builder/DebugDirectoryBuffer.cs
index 2cc85880d..c3a0dc300 100644
--- a/src/AsmResolver.PE/Debug/Builder/DebugDirectoryBuffer.cs
+++ b/src/AsmResolver.PE/Debug/Builder/DebugDirectoryBuffer.cs
@@ -27,7 +27,7 @@ public class DebugDirectoryBuffer : ISegment
         public void AddEntry(DebugDataEntry entry)
         {
             _headers.Add(entry);
-            if (entry.Contents != null)
+            if (entry.Contents is not null and not EmptyDebugDataSegment)
                 _streamsTable.Add(entry.Contents, 4);
         }
 
diff --git a/src/AsmResolver.PE/Debug/EmptyDebugDataSegment.cs b/src/AsmResolver.PE/Debug/EmptyDebugDataSegment.cs
new file mode 100644
index 000000000..402079a8e
--- /dev/null
+++ b/src/AsmResolver.PE/Debug/EmptyDebugDataSegment.cs
@@ -0,0 +1,43 @@
+using System.Diagnostics;
+using AsmResolver.IO;
+
+namespace AsmResolver.PE.Debug;
+
+/// <summary>
+/// Represents the contents of an empty debug data entry.
+/// </summary>
+public sealed class EmptyDebugDataSegment : IDebugDataSegment
+{
+    /// <summary>
+    /// Creates a new empty debug data segment for the provided debug data content.
+    /// </summary>
+    /// <param name="type">The content type.</param>
+    public EmptyDebugDataSegment(DebugDataType type)
+    {
+        Type = type;
+    }
+
+    /// <inheritdoc />
+    public DebugDataType Type { get; }
+
+    bool ISegment.CanUpdateOffsets => false;
+
+    ulong IOffsetProvider.Offset => 0;
+
+    uint IOffsetProvider.Rva => 0;
+
+    /// <inheritdoc />
+    void ISegment.UpdateOffsets(in RelocationParameters parameters)
+    {
+    }
+
+    /// <inheritdoc />
+    uint IWritable.GetPhysicalSize() => 0;
+
+    /// <inheritdoc />
+    uint ISegment.GetVirtualSize() => 0;
+
+    void IWritable.Write(BinaryStreamWriter writer)
+    {
+    }
+}
diff --git a/src/AsmResolver.PE/Debug/SerializedDebugDataEntry.cs b/src/AsmResolver.PE/Debug/SerializedDebugDataEntry.cs
index 79a388274..311adfeaf 100644
--- a/src/AsmResolver.PE/Debug/SerializedDebugDataEntry.cs
+++ b/src/AsmResolver.PE/Debug/SerializedDebugDataEntry.cs
@@ -45,6 +45,9 @@ public SerializedDebugDataEntry(
         {
             BinaryStreamReader reader;
 
+            if (_sizeOfData == 0)
+                return new EmptyDebugDataSegment(_type);
+
             if (_addressOfRawData == 0 || _context.File.MappingMode == File.PEMappingMode.Unmapped)
             {
                 if (!_context.File.TryCreateReaderAtFileOffset(_pointerToRawData, out reader))