Improve Crossgen2 map file emitter (dotnet#35459)

* Improve Crossgen2 map file emitter I have rewritten the file name emitter with two main goals in mind: 1) Fix the long-standing problem that map file wasn't showing true RVA's of the individual symbols / nodes, making it harder to correlate its information with in-memory R2R PE layout. 2) Add section size and statistics section roughly mimicking what JanV presented in his recent analytic breakdown of R2R contents. Thanks Tomas
waiyiptam · Apr 27, 2020 · a070557 · a070557
1 parent f283945
commit a070557
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Showing 6 changed files with 329 additions and 41 deletions.
diff --git a/src/coreclr/src/tools/crossgen2/ILCompiler.ReadyToRun/CodeGen/ReadyToRunObjectWriter.cs b/src/coreclr/src/tools/crossgen2/ILCompiler.ReadyToRun/CodeGen/ReadyToRunObjectWriter.cs
@@ -50,9 +50,9 @@ internal class ReadyToRunObjectWriter
         private readonly IEnumerable<DependencyNode> _nodes;
 
         /// <summary>
-        /// True when the executable generator should output a map file.
+        /// Set to non-null when the executable generator should output a map file.
         /// </summary>
-        private readonly bool _generateMapFile;
+        private readonly MapFileBuilder _mapFileBuilder;
 
 #if DEBUG
         private struct NodeInfo
@@ -78,31 +78,22 @@ public ReadyToRunObjectWriter(string objectFilePath, EcmaModule componentModule,
             _componentModule = componentModule;
             _nodes = nodes;
             _nodeFactory = factory;
-            _generateMapFile = generateMapFile;
+
+            if (generateMapFile)
+            {
+                _mapFileBuilder = new MapFileBuilder();
+            }
         }
 
         public void EmitPortableExecutable()
         {
             bool succeeded = false;
 
-            FileStream mapFileStream = null;
-            TextWriter mapFile = null;
-
             try
             {
-                if (_generateMapFile)
-                {
-                    string mapFileName = Path.ChangeExtension(_objectFilePath, ".map");
-                    mapFileStream = new FileStream(mapFileName, FileMode.Create, FileAccess.Write);
-                    mapFile = new StreamWriter(mapFileStream);
-                }
-
                 Stopwatch stopwatch = new Stopwatch();
                 stopwatch.Start();
 
-                if (mapFile != null)
-                    mapFile.WriteLine($@"R2R object emission started: {DateTime.Now}");
-
                 PEHeaderBuilder headerBuilder;
                 int timeDateStamp;
                 ISymbolNode r2rHeaderExportSymbol;
@@ -167,7 +158,7 @@ public void EmitPortableExecutable()
 
                     string name = null;
 
-                    if (mapFile != null)
+                    if (_mapFileBuilder != null)
                     {
                         name = depNode.GetType().ToString();
                         int firstGeneric = name.IndexOf('[');
@@ -182,7 +173,7 @@ public void EmitPortableExecutable()
                         }
                     }
 
-                    EmitObjectData(r2rPeBuilder, nodeContents, nodeIndex, name, node.Section, mapFile);
+                    EmitObjectData(r2rPeBuilder, nodeContents, nodeIndex, name, node.Section, _mapFileBuilder);
                 }
 
                 if (!_nodeFactory.CompilationModuleGroup.IsCompositeBuildMode || _componentModule != null)
@@ -201,6 +192,11 @@ public void EmitPortableExecutable()
                 {
                     r2rPeBuilder.Write(peStream, timeDateStamp);
 
+                    if (_mapFileBuilder != null)
+                    {
+                        _mapFileBuilder.SetFileSize(peStream.Length);
+                    }
+
                     // Compute MD5 hash of the output image and store that in the native DebugDirectory entry
                     using (var md5Hash = MD5.Create())
                     {
@@ -214,25 +210,18 @@ public void EmitPortableExecutable()
                     }
                 }
 
-                if (mapFile != null)
+                if (_mapFileBuilder != null)
                 {
-                    mapFile.WriteLine($@"R2R object emission finished: {DateTime.Now}, {stopwatch.ElapsedMilliseconds} msecs");
-                    mapFile.Flush();
-                    mapFileStream.Flush();
+                    r2rPeBuilder.AddSections(_mapFileBuilder);
+
+                    string mapFileName = Path.ChangeExtension(_objectFilePath, ".map");
+                    _mapFileBuilder.Save(mapFileName);
                 }
 
                 succeeded = true;
             }
             finally
             {
-                if (mapFile != null)
-                {
-                    mapFile.Dispose();
-                }
-                if (mapFileStream != null)
-                {
-                    mapFileStream.Dispose();
-                }
                 if (!succeeded)
                 {
                     // If there was an exception while generating the OBJ file, make sure we don't leave the unfinished
@@ -264,7 +253,7 @@ public void EmitPortableExecutable()
         /// <param name="name">Textual representation of the ObjecData blob in the map file</param>
         /// <param name="section">Section to emit the blob into</param>
         /// <param name="mapFile">Map file output stream</param>
-        private void EmitObjectData(R2RPEBuilder r2rPeBuilder, ObjectData data, int nodeIndex, string name, ObjectNodeSection section, TextWriter mapFile)
+        private void EmitObjectData(R2RPEBuilder r2rPeBuilder, ObjectData data, int nodeIndex, string name, ObjectNodeSection section, MapFileBuilder mapFileBuilder)
         {
 #if DEBUG
             for (int symbolIndex = 0; symbolIndex < data.DefinedSymbols.Length; symbolIndex++)
@@ -283,7 +272,7 @@ private void EmitObjectData(R2RPEBuilder r2rPeBuilder, ObjectData data, int node
             }
 #endif
 
-            r2rPeBuilder.AddObjectData(data, section, name, mapFile);
+            r2rPeBuilder.AddObjectData(data, section, name, mapFileBuilder);
         }
 
         public static void EmitObject(string objectFilePath, EcmaModule componentModule, IEnumerable<DependencyNode> nodes, NodeFactory factory, bool generateMapFile)

diff --git a/...rossgen2/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/MethodWithGCInfo.cs b/...rossgen2/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/MethodWithGCInfo.cs
@@ -303,5 +303,6 @@ public void InitializeInliningInfo(MethodDesc[] inlinedMethods)
 
         public int Offset => 0;
         public override bool IsShareable => throw new NotImplementedException();
+        public override bool ShouldSkipEmittingObjectNode(NodeFactory factory) => IsEmpty;
     }
 }
diff --git a/src/coreclr/src/tools/crossgen2/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj b/src/coreclr/src/tools/crossgen2/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj
@@ -95,6 +95,7 @@
     <Compile Include="..\..\Common\JitInterface\CorInfoTypes.VarInfo.cs" Link="JitInterface\CorInfoTypes.VarInfo.cs" />
     <Compile Include="..\..\Common\JitInterface\SystemVStructClassificator.cs" Link="JitInterface\SystemVStructClassificator.cs" />
     <Compile Include="..\..\Common\TypeSystem\Interop\InteropTypes.cs" Link="Interop\InteropTypes.cs" />
+    <Compile Include="ObjectWriter\MapFileBuilder.cs" />
     <Compile Include="CodeGen\ReadyToRunObjectWriter.cs" />
     <Compile Include="Compiler\CompilationModuleGroup.ReadyToRun.cs" />
     <Compile Include="Compiler\DependencyAnalysis\AllMethodsOnTypeNode.cs" />