Add WebCIL support

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -147,6 +147,7 @@
     <Compile Include="TypeSystem\ITypeDefinitionOrUnknown.cs" />
     <Compile Include="Util\BitOperations.cs" />
     <Compile Include="Util\Index.cs" />
+    <Compile Include="Metadata\WebCilFile.cs" />
     <None Include="Properties\DecompilerVersionInfo.template.cs" />
     <Compile Include="Semantics\OutVarResolveResult.cs" />
     <Compile Include="SingleFileBundle.cs" />

ICSharpCode.Decompiler/Metadata/MetadataExtensions.cs

@@ -1,6 +1,25 @@
-using System;
+// Copyright (c) 2018 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
 using System.Buffers.Binary;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Reflection.Metadata;
@@ -426,5 +445,23 @@ public static BlobReader AsBlobReader(this MetadataReader metadataReader)
 				return new(metadataReader.MetadataPointer, metadataReader.MetadataLength);
 			}
 		}
+
+		public static uint ReadULEB128(this BinaryReader reader)
+		{
+			uint val = 0;
+			int shift = 0;
+			while (true)
+			{
+				byte b = reader.ReadByte();
+				val |= (b & 0b0111_1111u) << shift;
+				if ((b & 0b1000_0000) == 0)
+					break;
+				shift += 7;
+				if (shift >= 35)
+					throw new OverflowException();
+			}
+			return val;
+		}
+
 	}
 }

ICSharpCode.Decompiler/Metadata/MetadataFile.cs

@@ -51,6 +51,7 @@ public enum MetadataFileKind
 		{
 			PortableExecutable,
 			ProgramDebugDatabase,
+			WebCIL,
 			Metadata
 		}
 

ICSharpCode.Decompiler/Metadata/WebCilFile.cs

@@ -0,0 +1,284 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// 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.Collections.Immutable;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.IO.MemoryMappedFiles;
+using System.Reflection.Metadata;
+using System.Text;
+
+using ICSharpCode.Decompiler.TypeSystem;
+
+#nullable enable
+
+namespace ICSharpCode.Decompiler.Metadata
+{
+	public class WebCilFile : MetadataFile, IDisposable, IModuleReference
+	{
+		readonly MemoryMappedViewAccessor view;
+		readonly long webcilOffset;
+
+		private WebCilFile(string fileName, long webcilOffset, long metadataOffset, MemoryMappedViewAccessor view, ImmutableArray<SectionHeader> sectionHeaders, ImmutableArray<WasmSection> wasmSections, MetadataReaderProvider provider, MetadataReaderOptions metadataOptions = MetadataReaderOptions.Default)
+			: base(MetadataFileKind.WebCIL, fileName, provider, metadataOptions, 0)
+		{
+			this.webcilOffset = webcilOffset;
+			this.MetadataOffset = (int)metadataOffset;
+			this.view = view;
+			this.SectionHeaders = sectionHeaders;
+			this.WasmSections = wasmSections;
+		}
+
+		public static WebCilFile? FromStream(string fileName, MetadataReaderOptions metadataOptions = MetadataReaderOptions.Default)
+		{
+			using var memoryMappedFile = MemoryMappedFile.CreateFromFile(fileName, FileMode.Open, null, 0, MemoryMappedFileAccess.Read);
+			var view = memoryMappedFile.CreateViewAccessor(0, 0, MemoryMappedFileAccess.Read);
+			try
+			{
+				// read magic "\0asm"
+				if (view.ReadUInt32(0) != WASM_MAGIC)
+					return null;
+
+				// read version
+				if (view.ReadUInt32(4) != 1)
+					return null;
+
+				using var stream = view.AsStream();
+				using var reader = new BinaryReader(stream, Encoding.UTF8, leaveOpen: true);
+
+				stream.Position += 8;
+
+				long metadataOffset = -1;
+				List<WasmSection> sections = new List<WasmSection>();
+
+				while (stream.Position < stream.Length)
+				{
+					WasmSectionId id = (WasmSectionId)reader.ReadByte();
+					uint size = reader.ReadULEB128();
+					sections.Add(new WasmSection(id, stream.Position, size, view));
+
+					if (id == WasmSectionId.Custom && size == 0)
+					{
+						break;
+					}
+					stream.Seek(size, SeekOrigin.Current);
+				}
+
+				foreach (var section in sections)
+				{
+					if (section.Id != WasmSectionId.Data || metadataOffset > -1)
+						continue;
+
+					stream.Seek(section.Offset, SeekOrigin.Begin);
+
+					uint numSegments = reader.ReadULEB128();
+					if (numSegments != 2)
+						continue;
+
+					// skip the first segment
+					if (reader.ReadByte() != 1)
+						continue;
+
+					long segmentLength = reader.ReadULEB128();
+					long segmentStart = reader.BaseStream.Position;
+
+					reader.BaseStream.Seek(segmentLength, SeekOrigin.Current);
+
+					if (reader.ReadByte() != 1)
+						continue;
+
+					segmentLength = reader.ReadULEB128();
+					if (TryReadWebCilSegment(reader, out var header, out metadataOffset, out var webcilOffset, out var sectionHeaders))
+					{
+						stream.Seek(metadataOffset, SeekOrigin.Begin);
+						var metadata = MetadataReaderProvider.FromMetadataStream(stream, MetadataStreamOptions.LeaveOpen | MetadataStreamOptions.PrefetchMetadata);
+
+						var result = new WebCilFile(fileName, webcilOffset, metadataOffset, view, ImmutableArray.Create(sectionHeaders), sections.ToImmutableArray(), metadata, metadataOptions);
+
+						view = null; // don't dispose the view, we're still using it in the sections
+						return result;
+					}
+				}
+
+				return null;
+			}
+			finally
+			{
+				view?.Dispose();
+			}
+		}
+
+		static unsafe bool TryReadWebCilSegment(BinaryReader reader, out WebcilHeader webcilHeader, out long metadataOffset, out long webcilOffset, [NotNullWhen(true)] out SectionHeader[]? sectionHeaders)
+		{
+			webcilHeader = default;
+			metadataOffset = -1;
+			sectionHeaders = null;
+
+			webcilOffset = reader.BaseStream.Position;
+
+			if (reader.ReadUInt32() != WEBCIL_MAGIC)
+				return false;
+
+			webcilHeader.VersionMajor = reader.ReadUInt16();
+			webcilHeader.VersionMinor = reader.ReadUInt16();
+			webcilHeader.CoffSections = reader.ReadUInt16();
+			_ = reader.ReadUInt16(); // reserved0
+			webcilHeader.PECliHeaderRVA = reader.ReadUInt32();
+			webcilHeader.PECliHeaderSize = reader.ReadUInt32();
+			webcilHeader.PEDebugRVA = reader.ReadUInt32();
+			webcilHeader.PEDebugSize = reader.ReadUInt32();
+
+			sectionHeaders = new SectionHeader[webcilHeader.CoffSections];
+			for (int i = 0; i < webcilHeader.CoffSections; i++)
+			{
+				sectionHeaders[i].VirtualSize = reader.ReadUInt32();
+				sectionHeaders[i].VirtualAddress = reader.ReadUInt32();
+				sectionHeaders[i].RawDataSize = reader.ReadUInt32();
+				sectionHeaders[i].RawDataPtr = reader.ReadUInt32();
+			}
+
+			long corHeaderStart = TranslateRVA(sectionHeaders, webcilOffset, webcilHeader.PECliHeaderRVA);
+			if (reader.BaseStream.Seek(corHeaderStart, SeekOrigin.Begin) != corHeaderStart)
+				return false;
+			int byteCount = reader.ReadInt32();
+			int majorVersion = reader.ReadUInt16();
+			int minorVersion = reader.ReadUInt16();
+			metadataOffset = TranslateRVA(sectionHeaders, webcilOffset, (uint)reader.ReadInt32());
+			return reader.BaseStream.Seek(metadataOffset, SeekOrigin.Begin) == metadataOffset;
+		}
+
+		public override int MetadataOffset { get; }
+
+		private static int GetContainingSectionIndex(IEnumerable<SectionHeader> sections, int rva)
+		{
+			int i = 0;
+			foreach (var section in sections)
+			{
+				if (rva >= section.VirtualAddress && rva < section.VirtualAddress + section.VirtualSize)
+				{
+					return i;
+				}
+				i++;
+			}
+			return -1;
+		}
+
+		private static long TranslateRVA(IEnumerable<SectionHeader> sections, long webcilOffset, uint rva)
+		{
+			foreach (var section in sections)
+			{
+				if (rva >= section.VirtualAddress && rva < section.VirtualAddress + section.VirtualSize)
+				{
+					return section.RawDataPtr + (rva - section.VirtualAddress) + webcilOffset;
+				}
+			}
+			throw new BadImageFormatException("RVA not found in any section");
+		}
+
+		public override MethodBodyBlock GetMethodBody(int rva)
+		{
+			var reader = GetSectionData(rva).GetReader();
+			return MethodBodyBlock.Create(reader);
+		}
+
+		public override int GetContainingSectionIndex(int rva)
+		{
+			return GetContainingSectionIndex(SectionHeaders, rva);
+		}
+
+		public override unsafe SectionData GetSectionData(int rva)
+		{
+			foreach (var section in SectionHeaders)
+			{
+				if (rva >= section.VirtualAddress && rva < section.VirtualAddress + section.VirtualSize)
+				{
+					byte* ptr = (byte*)0;
+					view.SafeMemoryMappedViewHandle.AcquirePointer(ref ptr);
+					return new SectionData(ptr + section.RawDataPtr + webcilOffset + (rva - section.VirtualAddress), (int)section.RawDataSize);
+				}
+			}
+			throw new BadImageFormatException("RVA not found in any section");
+		}
+
+		public override ImmutableArray<SectionHeader> SectionHeaders { get; }
+
+		public ImmutableArray<WasmSection> WasmSections { get; }
+
+		IModule? IModuleReference.Resolve(ITypeResolveContext context)
+		{
+			return new MetadataModule(context.Compilation, this, TypeSystemOptions.Default);
+		}
+
+		public void Dispose()
+		{
+			view.Dispose();
+		}
+
+		public struct WebcilHeader
+		{
+			public ushort VersionMajor;
+			public ushort VersionMinor;
+			public ushort CoffSections;
+			public uint PECliHeaderRVA;
+			public uint PECliHeaderSize;
+			public uint PEDebugRVA;
+			public uint PEDebugSize;
+		}
+
+		const uint WASM_MAGIC = 0x6d736100u; // "\0asm"
+		const uint WEBCIL_MAGIC = 0x4c496257u; // "WbIL"
+
+		[DebuggerDisplay("WasmSection {Id}: {Offset} {Size}")]
+		public class WasmSection
+		{
+			public WasmSectionId Id;
+			public long Offset;
+			public uint Size;
+			private MemoryMappedViewAccessor view;
+
+			public WasmSection(WasmSectionId id, long offset, uint size, MemoryMappedViewAccessor view)
+			{
+				this.Id = id;
+				this.Size = size;
+				this.Offset = offset;
+				this.view = view;
+			}
+		}
+
+		public enum WasmSectionId : byte
+		{
+			// order matters: enum values must match the WebAssembly spec
+			Custom = 0,
+			Type = 1,
+			Import = 2,
+			Function = 3,
+			Table = 4,
+			Memory = 5,
+			Global = 6,
+			Export = 7,
+			Start = 8,
+			Element = 9,
+			Code = 10,
+			Data = 11,
+			DataCount = 12,
+		}
+	}
+}

ICSharpCode.Decompiler/SRMExtensions.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Immutable;
+using System.IO;
+using System.IO.MemoryMappedFiles;
 using System.Reflection;
 using System.Reflection.Metadata;
 using System.Reflection.Metadata.Ecma335;
@@ -748,5 +750,11 @@ public static string ToILSyntax(this SignatureCallingConvention callConv)
 				_ => callConv.ToString().ToLowerInvariant()
 			};
 		}
+
+		public static UnmanagedMemoryStream AsStream(this MemoryMappedViewAccessor view)
+		{
+			long size = checked((long)view.SafeMemoryMappedViewHandle.ByteLength);
+			return new UnmanagedMemoryStream(view.SafeMemoryMappedViewHandle, 0, size);
+		}
 	}
 }

ICSharpCode.Decompiler/SingleFileBundle.cs

@@ -104,18 +104,12 @@ public struct Entry
 			public string RelativePath; // Path of an embedded file, relative to the Bundle source-directory.
 		}
 
-		static UnmanagedMemoryStream AsStream(MemoryMappedViewAccessor view)
-		{
-			long size = checked((long)view.SafeMemoryMappedViewHandle.ByteLength);
-			return new UnmanagedMemoryStream(view.SafeMemoryMappedViewHandle, 0, size);
-		}
-
 		/// <summary>
 		/// Reads the manifest header from the memory mapping.
 		/// </summary>
 		public static Header ReadManifest(MemoryMappedViewAccessor view, long bundleHeaderOffset)
 		{
-			using var stream = AsStream(view);
+			using var stream = view.AsStream();
 			stream.Seek(bundleHeaderOffset, SeekOrigin.Begin);
 			return ReadManifest(stream);
 		}