Merge pull request #583 from DaZombieKiller/pe-debug

Support EOF data in debug data entries.

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);
         }
 

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)
+    {
+    }
+}

src/AsmResolver.PE/Debug/SerializedDebugDataEntry.cs

@@ -43,17 +43,25 @@ public SerializedDebugDataEntry(
         /// <inheritdoc />
         protected override IDebugDataSegment? GetContents()
         {
+            BinaryStreamReader reader;
+
             if (_sizeOfData == 0)
-                return null;
+                return new EmptyDebugDataSegment(_type);
 
-            var reference = _context.File.GetReferenceToRva(_addressOfRawData);
-            if (!reference.CanRead)
+            if (_addressOfRawData == 0 || _context.File.MappingMode == File.PEMappingMode.Unmapped)
+            {
+                if (!_context.File.TryCreateReaderAtFileOffset(_pointerToRawData, out reader))
+                {
+                    _context.BadImage("Debug data entry contains an invalid file offset.");
+                    return null;
+                }
+            }
+            else if (!_context.File.TryCreateReaderAtRva(_addressOfRawData, out reader))
             {
                 _context.BadImage("Debug data entry contains an invalid RVA.");
                 return null;
             }
 
-            var reader = reference.CreateReader();
             if (_sizeOfData > reader.Length)
             {
                 _context.BadImage("Debug data entry contains a too large size.");