tag 0.6

svn path=/tags/cecil-0.6/; revision=86859

10 files changed, 530 insertions, 0 deletions

diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/AUTHORS b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/AUTHORS
new file mode 100644
index 00000000000..fcfe3126c23
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/AUTHORS
@@ -0,0 +1 @@
+Jb Evain  <jbevain@novell.com>
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/ChangeLog b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/ChangeLog
new file mode 100644
index 00000000000..c38c1db1abb
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/ChangeLog
@@ -0,0 +1,23 @@
+2007-08-28  Jb Evain  <jbevain@novell.com>
+
+	* Mono.Cecil.Mdb/MdbWriter.cs:
+		Rewrite variables infos.
+
+2007-08-27  Jb Evain  <jbevain@novell.com>
+
+	* Mono.Cecil.Mdb/MdbWriter.cs:
+		Rewrite using the direct mdb api.
+
+2007-02-21  Jb Evain  <jb@nurv.fr>
+
+	* Start working on local var debug infos emitting.
+
+2006-09-24  Jb Evain  <jbevain@gmail.com>
+
+	* start some work on the reader.
+
+2006-09-19  Jb Evain  <jbevain@gmail.com>
+
+	* first checkin in SVN:
+		This is the assembly to support reading and writing
+		from Mono's mdb symbol store.
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Makefile b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Makefile
new file mode 100644
index 00000000000..b8f72bd0cda
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Makefile
@@ -0,0 +1,12 @@
+thisdir = class/Mono.Cecil.Mdb
+include ../../build/rules.make
+
+LIBRARY = Mono.Cecil.Mdb.dll
+LIBRARY_SNK = ../mono.snk
+LIBRARY_PACKAGE = none
+
+LIB_MCS_FLAGS = /r:$(corlib) /r:Mono.Cecil.dll /d:CECIL -keyfile:$(LIBRARY_SNK)
+
+NO_TEST = yes
+
+include ../../build/library.make
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb.csproj b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb.csproj
new file mode 100644
index 00000000000..3f743608cfe
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb.csproj
@@ -0,0 +1,61 @@
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProductVersion>8.0.50727</ProductVersion>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{C5D12431-9C20-4789-8FEC-46094B0F81B5}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>Mono.Cecil.Mdb</RootNamespace>
+    <AssemblyName>Mono.Cecil.Mdb</AssemblyName>
+    <StartupObject>
+    </StartupObject>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>..\..\mcs\class\mono.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it.
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+  <ItemGroup>
+    <Compile Include="Mono.Cecil.Mdb\AssemblyInfo.cs" />
+    <Compile Include="Mono.Cecil.Mdb\MdbFactory.cs" />
+    <Compile Include="Mono.Cecil.Mdb\MdbReader.cs" />
+    <Compile Include="Mono.Cecil.Mdb\MdbWriter.cs" />
+    <Compile Include="Mono.CompilerServices.SymbolWriter\MonoSymbolFile.cs" />
+    <Compile Include="Mono.CompilerServices.SymbolWriter\MonoSymbolTable.cs" />
+    <Compile Include="Mono.CompilerServices.SymbolWriter\MonoSymbolWriter.cs" />
+    <Compile Include="Mono.CompilerServices.SymbolWriter\SymbolWriterImpl.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\mcs\class\Mono.Cecil\Mono.Cecil.csproj">
+      <Project>{D8F63DFF-5230-43E4-9AB2-DA6E721A1FAE}</Project>
+      <Name>Mono.Cecil</Name>
+    </ProjectReference>
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb.dll.sources b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb.dll.sources
new file mode 100644
index 00000000000..092a51e9432
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb.dll.sources
@@ -0,0 +1,8 @@
+./Mono.Cecil.Mdb/AssemblyInfo.cs
+./Mono.Cecil.Mdb/MdbFactory.cs
+./Mono.Cecil.Mdb/MdbReader.cs
+./Mono.Cecil.Mdb/MdbWriter.cs
+../Mono.CompilerServices.SymbolWriter/MonoSymbolFile.cs
+../Mono.CompilerServices.SymbolWriter/MonoSymbolTable.cs
+../Mono.CompilerServices.SymbolWriter/MonoSymbolWriter.cs
+../Mono.CompilerServices.SymbolWriter/SymbolWriterImpl.cs
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/AssemblyInfo.cs b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/AssemblyInfo.cs
new file mode 100644
index 00000000000..5debf10fff0
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/AssemblyInfo.cs
@@ -0,0 +1,43 @@
+//
+// AssemblyInfo.cs
+//
+// Author:
+//   Jb Evain (jbevain@gmail.com)
+//
+// (C) 2006 Jb Evain
+//
+// 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.Reflection;
+using System.Runtime.InteropServices;
+
+[assembly: AssemblyTitle ("Mono.Cecil.Mdb")]
+[assembly: AssemblyDescription ("Support for the mdb symbols store in Cecil")]
+[assembly: AssemblyConfiguration ("")]
+[assembly: AssemblyProduct ("Mono.Cecil")]
+[assembly: AssemblyCopyright ("(C) 2006, Jb Evain")]
+[assembly: AssemblyCulture ("")]
+
+[assembly: CLSCompliant (false)]
+[assembly: ComVisible (false)]
+
+[assembly: AssemblyVersion ("0.2.0.0")]
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbFactory.cs b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbFactory.cs
new file mode 100644
index 00000000000..0d1944ccf33
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbFactory.cs
@@ -0,0 +1,49 @@
+//
+// MdbFactory.cs
+//
+// Author:
+//   Jb Evain (jbevain@gmail.com)
+//
+// (C) 2006 Jb Evain
+//
+// 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.
+//
+
+namespace Mono.Cecil.Mdb {
+
+	using System;
+
+	using Mono.Cecil.Cil;
+
+	using Mono.CompilerServices.SymbolWriter;
+
+	public class MdbFactory : ISymbolStoreFactory {
+
+		public ISymbolReader CreateReader (ModuleDefinition module, string assembly)
+		{
+			return new MdbReader (MonoSymbolFile.ReadSymbolFile (module.Assembly, assembly));
+		}
+
+		public ISymbolWriter CreateWriter (ModuleDefinition module, string assembly)
+		{
+			return new MdbWriter (module.Mvid, assembly);
+		}
+	}
+}
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbReader.cs b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbReader.cs
new file mode 100644
index 00000000000..a40d44e973a
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbReader.cs
@@ -0,0 +1,152 @@
+//
+// MdbReader.cs
+//
+// Author:
+//   Jb Evain (jbevain@gmail.com)
+//
+// (C) 2006 Jb Evain
+//
+// 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.
+//
+
+namespace Mono.Cecil.Mdb {
+
+	using System.Collections;
+
+	using Mono.Cecil.Cil;
+
+	using Mono.CompilerServices.SymbolWriter;
+
+	class MdbReader : ISymbolReader {
+
+		MonoSymbolFile m_symFile;
+		Hashtable m_documents;
+		Hashtable m_scopes;
+
+		public MdbReader (MonoSymbolFile symFile)
+		{
+			m_symFile = symFile;
+			m_documents = new Hashtable ();
+			m_scopes = new Hashtable ();
+		}
+
+		Hashtable GetInstructions (MethodBody body)
+		{
+			Hashtable instructions = new Hashtable (body.Instructions.Count);
+			foreach (Instruction i in body.Instructions)
+				instructions.Add (i.Offset, i);
+
+			return instructions;
+		}
+
+		Instruction GetInstruction (MethodBody body, Hashtable instructions, int offset)
+		{
+			Instruction instr = (Instruction) instructions [offset];
+			if (instr != null)
+				return instr;
+
+			return body.Instructions.Outside;
+		}
+
+		public void Read (MethodBody body)
+		{
+			MethodEntry entry = m_symFile.GetMethodByToken ((int) body.Method.MetadataToken.ToUInt ());
+			if (entry == null)
+				return;
+
+			Hashtable instructions = GetInstructions(body);
+			ReadScopes (entry, body, instructions);
+			ReadLineNumbers (entry, instructions);
+			ReadLocalVariables (entry, body);
+		}
+
+		void ReadLocalVariables (MethodEntry entry, MethodBody body)
+		{
+			foreach (LocalVariableEntry loc in entry.Locals) {
+				Scope scope = m_scopes [loc.BlockIndex] as Scope;
+				if (scope == null)
+					continue;
+
+				VariableDefinition var = body.Variables [loc.Index];
+				var.Name = loc.Name;
+				scope.Variables.Add (var);
+			}
+		}
+
+		void ReadLineNumbers (MethodEntry entry, Hashtable instructions)
+		{
+			foreach (LineNumberEntry line in entry.LineNumbers) {
+				Instruction instr = instructions [line.Offset] as Instruction;
+				if (instr == null)
+					continue;
+
+				Document doc = GetDocument (entry.SourceFile);
+				instr.SequencePoint = new SequencePoint (doc);
+				instr.SequencePoint.StartLine = line.Row;
+				instr.SequencePoint.EndLine = line.Row;
+			}
+		}
+
+		Document GetDocument (SourceFileEntry file)
+		{
+			Document doc = m_documents [file.FileName] as Document;
+			if (doc != null)
+				return doc;
+
+			doc = new Document (file.FileName);
+
+			m_documents [file.FileName] = doc;
+			return doc;
+		}
+
+		void ReadScopes (MethodEntry entry, MethodBody body, Hashtable instructions)
+		{
+			foreach (LexicalBlockEntry scope in entry.LexicalBlocks) {
+				Scope s = new Scope ();
+				s.Start = GetInstruction (body, instructions, scope.StartOffset);
+				s.End = GetInstruction(body, instructions, scope.EndOffset);
+				m_scopes [scope.Index] = s;
+
+				if (!AddScope (body, s))
+					body.Scopes.Add (s);
+			}
+		}
+
+		bool AddScope (IScopeProvider provider, Scope s)
+		{
+			foreach (Scope scope in provider.Scopes) {
+				if (AddScope (scope, s))
+					return true;
+
+				if (s.Start.Offset >= scope.Start.Offset && s.End.Offset <= scope.End.Offset) {
+					scope.Scopes.Add (s);
+					return true;
+				}
+			}
+
+			return false;
+		}
+
+		public void Dispose ()
+		{
+			m_symFile.Dispose ();
+		}
+	}
+}
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbWriter.cs b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbWriter.cs
new file mode 100644
index 00000000000..eb302a8ac4d
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/Mono.Cecil.Mdb/MdbWriter.cs
@@ -0,0 +1,179 @@
+//
+// MdbWriter.cs
+//
+// Author:
+//   Jb Evain (jbevain@novell.com)
+//
+// (C) 2007 Novell, Inc.
+//
+// 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.
+//
+
+// Inspired by the pdb2mdb tool written by Robert Jordan, thanks Robert!
+
+namespace Mono.Cecil.Mdb {
+
+	using System;
+	using System.Collections;
+
+	using Mono.CompilerServices.SymbolWriter;
+
+	using Mono.Cecil;
+	using Mono.Cecil.Cil;
+
+	class MdbWriter : ISymbolWriter {
+
+		Guid m_mvid;
+		MonoSymbolWriter m_writer;
+
+		Hashtable m_documents;
+
+		public MdbWriter (Guid mvid, string assembly)
+		{
+			m_mvid = mvid;
+			m_writer = new MonoSymbolWriter (assembly);
+			m_documents = new Hashtable ();
+		}
+
+		static Instruction [] GetInstructions (MethodBody body)
+		{
+			ArrayList list = new ArrayList ();
+			foreach (Instruction instruction in body.Instructions)
+				if (instruction.SequencePoint != null)
+					list.Add (instruction);
+
+			return list.ToArray (typeof (Instruction)) as Instruction [];
+		}
+
+		SourceFile GetSourceFile (Document document)
+		{
+			string url = document.Url;
+			SourceFile file = m_documents [url] as SourceFile;
+			if (file != null)
+				return file;
+
+			file = new SourceFile (m_writer.DefineDocument (url));
+			m_documents [url] = file;
+			return file;
+		}
+
+		void Populate (Instruction [] instructions, int [] offsets,
+			int [] startRows, int [] startCols, int [] endRows, int [] endCols,
+			out SourceFile file)
+		{
+			SourceFile document = null;
+
+			for (int i = 0; i < instructions.Length; i++) {
+				Instruction instr = (Instruction) instructions [i];
+				offsets [i] = instr.Offset;
+
+				if (document == null)
+					document = GetSourceFile (instr.SequencePoint.Document);
+
+				startRows [i] = instr.SequencePoint.StartLine;
+				startCols [i] = instr.SequencePoint.StartColumn;
+				endRows [i] = instr.SequencePoint.EndLine;
+				endCols [i] = instr.SequencePoint.EndColumn;
+			}
+
+			file = document;
+		}
+
+		public void Write (MethodBody body, byte [][] variables)
+		{
+			SourceMethod meth = new SourceMethod (body.Method);
+
+			SourceFile file;
+
+			Instruction [] instructions = GetInstructions (body);
+			int length = instructions.Length;
+			if (length == 0)
+				return;
+
+			int [] offsets = new int [length];
+			int [] startRows = new int [length];
+			int [] startCols = new int [length];
+			int [] endRows = new int [length];
+			int [] endCols = new int [length];
+
+			Populate (instructions, offsets, startRows, startCols, endRows, endCols, out file);
+
+			m_writer.OpenMethod (file, meth,
+				startRows [0], startCols [0],
+				endRows [length - 1], endCols [length - 1]);
+
+			for (int i = 0; i < length; i++)
+				m_writer.MarkSequencePoint (offsets [i], startRows [i], startCols [i]);
+
+			MarkVariables (body, variables);
+
+			m_writer.CloseMethod ();
+		}
+
+		void MarkVariables (MethodBody body, byte [][] variables)
+		{
+			for (int i = 0; i < body.Variables.Count; i++) {
+				VariableDefinition var = body.Variables [i];
+				m_writer.DefineLocalVariable (i, var.Name, variables [i]);
+			}
+		}
+
+		public void Dispose ()
+		{
+			m_writer.WriteSymbolFile (m_mvid);
+		}
+
+		class SourceFile : ISourceFile {
+
+			SourceFileEntry m_entry;
+
+			public SourceFileEntry Entry {
+				get { return m_entry; }
+			}
+
+			public SourceFile (SourceFileEntry entry)
+			{
+				m_entry = entry;
+			}
+		}
+
+		class SourceMethod : ISourceMethod {
+
+			MethodDefinition m_method;
+
+			public string Name {
+				get { return m_method.Name; }
+			}
+
+			public int NamespaceID {
+				get { return 0; }
+			}
+
+			public int Token {
+				get { return (int) m_method.MetadataToken.ToUInt (); }
+			}
+
+			public SourceMethod (MethodDefinition method)
+			{
+				m_method = method;
+			}
+		}
+	}
+}
diff --git a/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/README b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/README
new file mode 100644
index 00000000000..ef817611010
--- /dev/null
+++ b/mcs/class/Mono.Cecil/Mono.Cecil.Mdb/README
@@ -0,0 +1,2 @@
+Mono.Cecil.Mdb is an internal assembly used by Mono.Cecil to
+read and write the Mono Debugging Symbols file format.