PrepareForReadyToRunCompilation.cs

// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.IO;
using System.Runtime.InteropServices;
using System.Reflection.PortableExecutable;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;
using System.Reflection.Metadata;
using System.Reflection;

namespace Microsoft.NET.Build.Tasks
{
    public class PrepareForReadyToRunCompilation : TaskBase
    {
        public ITaskItem[] Assemblies { get; set; }
        public string[] ExcludeList { get; set; }
        public bool EmitSymbols { get; set; }
        public bool ReadyToRunUseCrossgen2 { get; set; }

        [Required]
        public string OutputPath { get; set; }
        [Required]
        public bool IncludeSymbolsInSingleFile { get; set; }

        public ITaskItem CrossgenTool { get; set; }
        public ITaskItem Crossgen2Tool { get; set; }

        // Output lists of files to compile. Currently crossgen has to run in two steps, the first to generate the R2R image
        // and the second to create native PDBs for the compiled images (the output of the first step is an input to the second step)
        [Output]
        public ITaskItem[] ReadyToRunCompileList => _compileList.ToArray();
        [Output]
        public ITaskItem[] ReadyToRunSymbolsCompileList => _symbolsCompileList.ToArray();

        // Output files to publish after compilation. These lists are equivalent to the input list, but contain the new
        // paths to the compiled R2R images and native PDBs.
        [Output]
        public ITaskItem[] ReadyToRunFilesToPublish => _r2rFiles.ToArray();

        [Output]
        public ITaskItem[] ReadyToRunAssembliesToReference => _r2rReferences.ToArray();

        private List<ITaskItem> _compileList = new List<ITaskItem>();
        private List<ITaskItem> _symbolsCompileList = new List<ITaskItem>();
        private List<ITaskItem> _r2rFiles = new List<ITaskItem>();
        private List<ITaskItem> _r2rReferences = new List<ITaskItem>();

        protected override void ExecuteCore()
        {
            // Future: when crossgen2 supports generating PDBs, update this to check crossgen2 when we are using crossgen2.
            string diaSymReaderPath = CrossgenTool?.GetMetadata("DiaSymReader");
            bool hasValidDiaSymReaderLib = !string.IsNullOrEmpty(diaSymReaderPath) && File.Exists(diaSymReaderPath);

            // Process input lists of files
            ProcessInputFileList(Assemblies, _compileList, _symbolsCompileList, _r2rFiles, _r2rReferences, hasValidDiaSymReaderLib);
        }

        private void ProcessInputFileList(
            ITaskItem[] inputFiles, 
            List<ITaskItem> imageCompilationList,
            List<ITaskItem> symbolsCompilationList,
            List<ITaskItem> r2rFilesPublishList, 
            List<ITaskItem> r2rReferenceList,
            bool hasValidDiaSymReaderLib)
        {
            if (inputFiles == null)
            {
                return;
            }
            
            var exclusionSet = ExcludeList == null ? null : new HashSet<string>(ExcludeList, StringComparer.OrdinalIgnoreCase);

            foreach (var file in inputFiles)
            {
                var eligibility = GetInputFileEligibility(file, exclusionSet);

                if (eligibility == Eligibility.None)
                {
                    continue;
                }

                r2rReferenceList.Add(file);

                if (eligibility == Eligibility.ReferenceOnly)
                {
                    continue;
                }

                var outputR2RImageRelativePath = file.GetMetadata(MetadataKeys.RelativePath);
                var outputR2RImage = Path.Combine(OutputPath, outputR2RImageRelativePath);

                // This TaskItem is the IL->R2R entry, for an input assembly that needs to be compiled into a R2R image. This will be used as
                // an input to the ReadyToRunCompiler task
                TaskItem r2rCompilationEntry = new TaskItem(file);
                r2rCompilationEntry.SetMetadata("OutputR2RImage", outputR2RImage);
                r2rCompilationEntry.RemoveMetadata(MetadataKeys.OriginalItemSpec);
                imageCompilationList.Add(r2rCompilationEntry);

                // This TaskItem corresponds to the output R2R image. It is equivalent to the input TaskItem, only the ItemSpec for it points to the new path
                // for the newly created R2R image
                TaskItem r2rFileToPublish = new TaskItem(file);
                r2rFileToPublish.ItemSpec = outputR2RImage;
                r2rFileToPublish.RemoveMetadata(MetadataKeys.OriginalItemSpec);
                r2rFilesPublishList.Add(r2rFileToPublish);

                // Note: ReadyToRun PDB/Map files are not needed for debugging. They are only used for profiling, therefore the default behavior is to not generate them
                // unless an explicit PublishReadyToRunEmitSymbols flag is enabled by the app developer. There is also another way to profile that the runtime supports, which does
                // not rely on the native PDBs/Map files, so creating them is really an opt-in option, typically used by advanced users.
                // For debugging, only the IL PDBs are required.
                if (EmitSymbols)
                {
                    string outputPDBImageRelativePath = null, outputPDBImage = null, createPDBCommand = null;

                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && hasValidDiaSymReaderLib)
                    {
                        outputPDBImage = Path.ChangeExtension(outputR2RImage, "ni.pdb");
                        outputPDBImageRelativePath = Path.ChangeExtension(outputR2RImageRelativePath, "ni.pdb");
                        createPDBCommand = $"/CreatePDB \"{Path.GetDirectoryName(outputPDBImage)}\"";
                    }
                    else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
                    {
                        using (FileStream fs = new FileStream(file.ItemSpec, FileMode.Open, FileAccess.Read))
                        {
                            PEReader pereader = new PEReader(fs);
                            MetadataReader mdReader = pereader.GetMetadataReader();
                            Guid mvid = mdReader.GetGuid(mdReader.GetModuleDefinition().Mvid);

                            outputPDBImage = Path.ChangeExtension(outputR2RImage, "ni.{" + mvid + "}.map");
                            outputPDBImageRelativePath = Path.ChangeExtension(outputR2RImageRelativePath, "ni.{" + mvid + "}.map");
                            createPDBCommand = $"/CreatePerfMap \"{Path.GetDirectoryName(outputPDBImage)}\"";
                        }
                    }

                    if (outputPDBImage != null)
                    {
                        // This TaskItem is the R2R->R2RPDB entry, for a R2R image that was just created, and for which we need to create native PDBs. This will be used as
                        // an input to the ReadyToRunCompiler task
                        TaskItem pdbCompilationEntry = new TaskItem(file);
                        pdbCompilationEntry.ItemSpec = outputR2RImage;
                        pdbCompilationEntry.SetMetadata("OutputPDBImage", outputPDBImage);
                        pdbCompilationEntry.SetMetadata("CreatePDBCommand", createPDBCommand);
                        symbolsCompilationList.Add(pdbCompilationEntry);

                        // This TaskItem corresponds to the output PDB image. It is equivalent to the input TaskItem, only the ItemSpec for it points to the new path
                        // for the newly created PDB image.
                        TaskItem r2rSymbolsFileToPublish = new TaskItem(file);
                        r2rSymbolsFileToPublish.ItemSpec = outputPDBImage;
                        r2rSymbolsFileToPublish.SetMetadata(MetadataKeys.RelativePath, outputPDBImageRelativePath);
                        r2rSymbolsFileToPublish.RemoveMetadata(MetadataKeys.OriginalItemSpec);
                        if (!IncludeSymbolsInSingleFile)
                        {
                            r2rSymbolsFileToPublish.SetMetadata(MetadataKeys.ExcludeFromSingleFile, "true");
                        }

                        r2rFilesPublishList.Add(r2rSymbolsFileToPublish);
                    }
                }
            }
        }

        private enum Eligibility
        {
            None,
            ReferenceOnly,
            CompileAndReference
        };

        private static Eligibility GetInputFileEligibility(ITaskItem file, HashSet<string> exclusionSet)
        {
            // Check to see if this is a valid ILOnly image that we can compile
            using (FileStream fs = new FileStream(file.ItemSpec, FileMode.Open, FileAccess.Read))
            {
                try
                {
                    using (var pereader = new PEReader(fs))
                    {
                        if (!pereader.HasMetadata)
                        {
                            return Eligibility.None;
                        }

                        MetadataReader mdReader = pereader.GetMetadataReader();
                        if (!mdReader.IsAssembly)
                        {
                            return Eligibility.None;
                        }
                        
                        if (IsReferenceAssembly(mdReader))
                        {
                            // crossgen can only take implementation assemblies, even as references
                            return Eligibility.None;
                        }

                        if ((pereader.PEHeaders.CorHeader.Flags & CorFlags.ILOnly) != CorFlags.ILOnly)
                        {
                            return Eligibility.ReferenceOnly;
                        }

                        if (file.HasMetadataValue(MetadataKeys.ReferenceOnly, "true"))
                        {
                            return Eligibility.ReferenceOnly;
                        }

                        if (exclusionSet != null && exclusionSet.Contains(Path.GetFileName(file.ItemSpec)))
                        {
                            return Eligibility.ReferenceOnly;
                        }

                        // save these most expensive checks for last. We don't want to scan all references for IL code
                        if (ReferencesWinMD(mdReader) || !HasILCode(pereader, mdReader))
                        {
                            return Eligibility.ReferenceOnly;
                        }

                        return Eligibility.CompileAndReference;
                    }
                }
                catch (BadImageFormatException)
                {
                    // Not a valid assembly file
                    return Eligibility.None;
                }
            }
        }

        private static bool IsReferenceAssembly(MetadataReader mdReader)
        {
            foreach (var attributeHandle in mdReader.GetAssemblyDefinition().GetCustomAttributes())
            {
                EntityHandle attributeCtor = mdReader.GetCustomAttribute(attributeHandle).Constructor;

                StringHandle attributeTypeName = default;
                StringHandle attributeTypeNamespace = default;

                if (attributeCtor.Kind == HandleKind.MemberReference)
                {
                    EntityHandle attributeMemberParent = mdReader.GetMemberReference((MemberReferenceHandle)attributeCtor).Parent;
                    if (attributeMemberParent.Kind == HandleKind.TypeReference)
                    {
                        TypeReference attributeTypeRef = mdReader.GetTypeReference((TypeReferenceHandle)attributeMemberParent);
                        attributeTypeName = attributeTypeRef.Name;
                        attributeTypeNamespace = attributeTypeRef.Namespace;
                    }
                }
                else if (attributeCtor.Kind == HandleKind.MethodDefinition)
                {
                    TypeDefinitionHandle attributeTypeDefHandle = mdReader.GetMethodDefinition((MethodDefinitionHandle)attributeCtor).GetDeclaringType();
                    TypeDefinition attributeTypeDef = mdReader.GetTypeDefinition(attributeTypeDefHandle);
                    attributeTypeName = attributeTypeDef.Name;
                    attributeTypeNamespace = attributeTypeDef.Namespace;
                }

                if (!attributeTypeName.IsNil &&
                    !attributeTypeNamespace.IsNil &&
                    mdReader.StringComparer.Equals(attributeTypeName, "ReferenceAssemblyAttribute") &&
                    mdReader.StringComparer.Equals(attributeTypeNamespace, "System.Runtime.CompilerServices"))
                {
                    return true;
                }
            }

            return false;
        }

        private static bool ReferencesWinMD(MetadataReader mdReader)
        {
            foreach (var assemblyRefHandle in mdReader.AssemblyReferences)
            {
                AssemblyReference assemblyRef = mdReader.GetAssemblyReference(assemblyRefHandle);
                if ((assemblyRef.Flags & AssemblyFlags.WindowsRuntime) == AssemblyFlags.WindowsRuntime)
                {
                    return true;
                }
            }

            return false;
        }

        private static bool HasILCode(PEReader peReader, MetadataReader mdReader)
        {
            foreach (var methoddefHandle in mdReader.MethodDefinitions)
            {
                MethodDefinition methodDef = mdReader.GetMethodDefinition(methoddefHandle);
                if (methodDef.RelativeVirtualAddress > 0)
                {
                    return true;
                }
            }

            return false;
        }
    }
}