From 7470658080d3ff62cac61060cb0d65349d35100d Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Fri, 12 Apr 2019 13:19:19 -0700
Subject: [PATCH 1/6] Add ILLink targets and tests

---
 .../Microsoft.NET.Build.Tasks.csproj          |   1 +
 .../targets/Microsoft.NET.ILLink.targets      | 110 +++++++
 .../targets/Microsoft.NET.Publish.targets     |  12 +
 .../targets/Microsoft.NET.Sdk.targets         |   1 +
 .../GivenThatWeWantToRunILLink.cs             | 303 ++++++++++++++++++
 5 files changed, 427 insertions(+)
 create mode 100644 src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
 create mode 100644 src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/Microsoft.NET.Build.Tasks.csproj b/src/Tasks/Microsoft.NET.Build.Tasks/Microsoft.NET.Build.Tasks.csproj
index 9410041e9314..7d3f218b87c2 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/Microsoft.NET.Build.Tasks.csproj
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/Microsoft.NET.Build.Tasks.csproj
@@ -104,6 +104,7 @@
       <Stage0SdkFile Include="$(_Stage0SdksFolder)\Microsoft.NET.Sdk.Web.ProjectSystem\**" SdkName="Microsoft.NET.Sdk.Web.ProjectSystem" />
       <Stage0SdkFile Include="$(_Stage0SdksFolder)\Microsoft.NET.Sdk.Razor\**" SdkName="Microsoft.NET.Sdk.Razor" />
       <Stage0SdkFile Include="$(_Stage0SdksFolder)\Microsoft.NET.Sdk.WindowsDesktop\**" SdkName="Microsoft.NET.Sdk.WindowsDesktop" />
+      <Stage0SdkFile Include="$(_Stage0SdksFolder)\ILLink.Tasks\**" SdkName="ILLink.Tasks" />
       <LayoutFile Include="@(Stage0SdkFile)">
         <TargetPath>..\%(Stage0SdkFile.SdkName)\%(Stage0SdkFile.RecursiveDir)%(Stage0SdkFile.Filename)%(Stage0SdkFile.Extension)</TargetPath>
       </LayoutFile>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
new file mode 100644
index 000000000000..cb692865217f
--- /dev/null
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
@@ -0,0 +1,110 @@
+<!--
+***********************************************************************************************
+Microsoft.NET.ILLink.targets
+
+WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and have
+          created a backup copy.  Incorrect changes to this file will make it
+          impossible to load or build your projects from the command-line or the IDE.
+
+Copyright (c) .NET Foundation. All rights reserved.
+***********************************************************************************************
+-->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+  <Import Project="Sdk.props" Sdk="ILLink.Tasks" />
+
+  <PropertyGroup>
+    <ILTransformDependsOn>$(ILTransformDependsOn);ILLink</ILTransformDependsOn>
+    <IntermediateLinkDir Condition=" '$(IntermediateLinkDir)' == '' ">$(IntermediateOutputPath)linked</IntermediateLinkDir>
+    <!-- Used to enable incremental build for the linker target. -->
+    <_LinkSemaphore>$(IntermediateOutputPath)Link.semaphore</_LinkSemaphore>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <LinkerRootDescriptors Include="$(LinkerRootDescriptors)" />
+  </ItemGroup>
+
+  <!--
+    ============================================================
+                     ILLink
+
+    Replace the files to be published with versions that have been
+    passed through the linker. Also prevent removed files from being
+    included in the generated deps.json.
+    ============================================================
+    -->
+  <Target Name="ILLink"
+          Condition=" '$(LinkDuringPublish)' == 'true' "
+          DependsOnTargets="RunILLink">
+
+    <!-- For now, use ResolvedFileToPublish as input/output. This
+         should go away in favor of a well-defined set of runtime
+         assemblies with https://github.com/dotnet/sdk/issues/3109. -->
+    <ItemGroup>
+      <_LinkedResolvedFileToPublish Include="@(_LinkedResolvedFileToPublishCandidates)" Condition="Exists('%(Identity)')" />
+      <ResolvedFileToPublish Remove="@(_ManagedAssembliesToLink)" />
+      <ResolvedFileToPublish Include="@(_LinkedResolvedFileToPublish)" />
+    </ItemGroup>
+
+    <!-- Use _PublishConflictPackageFiles to remove assemblies from
+         the deps file. This will change with the fix to
+         https://github.com/dotnet/sdk/issues/3010. -->
+    <ItemGroup>
+      <_RemovedManagedAssemblies Include="@(_ManagedAssembliesToLink)" Condition="!Exists('$(IntermediateLinkDir)/%(Filename)%(Extension)')" />
+      <_PublishConflictPackageFiles Include="@(_RemovedManagedAssemblies)" />
+    </ItemGroup>
+
+  </Target>
+
+
+  <!--
+    ============================================================
+                     RunILLink
+
+    Execute the linker. This target runs incrementally, only executing
+    if the output semaphore file is out of date with respect to the inputs.
+    ============================================================
+    -->
+   <UsingTask TaskName="ILLink" AssemblyFile="$(ILLinkTasksAssembly)" />
+   <Target Name="RunILLink"
+           DependsOnTargets="_ComputeManagedAssembliesToLink"
+           Inputs="@(_ManagedAssembliesToLink);@(LinkerRootDescriptors);@(ReferencePath)"
+           Outputs="$(_LinkSemaphore)">
+
+     <Delete Files="@(_LinkedResolvedFileToPublishCandidates)" />
+     <!-- TODO: add ReferenceAssemblyPaths="@(ReferencePath)" -->
+     <ILLink AssemblyPaths="@(_ManagedAssembliesToLink)"
+             RootAssemblyNames="@(IntermediateAssembly->'%(Filename)')"
+             RootDescriptorFiles="@(LinkerRootDescriptors)"
+             OutputDirectory="$(IntermediateLinkDir)"
+             ExtraArgs="$(ExtraLinkerArgs) --skip-unresolved true" />
+
+     <Touch Files="$(_LinkSemaphore)" AlwaysCreate="true" />
+
+  </Target>
+
+  <!--
+    ============================================================
+                     _ComputeManagedAssembliesToLink
+
+    Compute the set of inputs to the linker. Currently this uses a
+    heuristic to get the relevant input from ResolvedFileToPublish,
+    but in the future this should be replaced with the exact set of
+    runtime assemblies that will be in the deps file.
+    ============================================================
+    -->
+  <UsingTask TaskName="ComputeManagedAssemblies" AssemblyFile="$(ILLinkTasksAssembly)" />
+  <Target Name="_ComputeManagedAssembliesToLink">
+    <ComputeManagedAssemblies Assemblies="@(ResolvedFileToPublish)">
+      <Output TaskParameter="ManagedAssemblies" ItemName="_ManagedAssembliesToLink" />
+    </ComputeManagedAssemblies>
+
+    <ItemGroup>
+      <_ManagedAssembliesToLink Remove="@(_ManagedResolvedFileToPublish->WithMetadataValue('AssetType', 'resources'))" />
+      <_LinkedResolvedFileToPublishCandidates Include="@(_ManagedAssembliesToLink->'$(IntermediateLinkDir)/%(Filename)%(Extension)')" />
+    </ItemGroup>
+
+  </Target>
+
+
+</Project>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
index 51cf7dfb4d07..a169bf76ce8e 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
@@ -107,6 +107,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
   <Target Name="ComputeAndCopyFilesToPublishDirectory"
           DependsOnTargets="ComputeFilesToPublish;
+                            ILTransform;
                             CreateReadyToRunImages;
                             CopyFilesToPublishDirectory" />
 
@@ -196,6 +197,17 @@ Copyright (c) .NET Foundation. All rights reserved.
     </Copy>
   </Target>
 
+  <!--
+    ============================================================
+                                        ILTransform
+
+    Extension point for IL transformations.
+    ============================================================
+    -->
+  <Target Name="ILTransform"
+          Condition="'$(_TargetFrameworkVersionWithoutV)' >= '3.0' And '$(TargetFrameworkIdentifier)' == '.NETCoreApp'"
+          DependsOnTargets="$(ILTransformDependsOn)" />
+
   <!--
     ============================================================
                                         CreateReadyToRunImages
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
index 05b9790b4a23..5b3fac62b267 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
@@ -753,4 +753,5 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.Sdk.CSharp.targets" Condition="'$(Language)' == 'C#'" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.Sdk.VisualBasic.targets" Condition="'$(Language)' == 'VB'" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.Sdk.FSharp.targets" Condition="'$(Language)' == 'F#'" />
+  <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.ILLink.targets" />
 </Project>
diff --git a/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs b/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
new file mode 100644
index 000000000000..5718c9e0b2b8
--- /dev/null
+++ b/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
@@ -0,0 +1,303 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Reflection.Metadata;
+using System.Reflection.PortableExecutable;
+using FluentAssertions;
+using Microsoft.Extensions.DependencyModel;
+using Microsoft.NET.TestFramework;
+using Microsoft.NET.TestFramework.Assertions;
+using Microsoft.NET.TestFramework.Commands;
+using Microsoft.NET.TestFramework.ProjectConstruction;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Microsoft.NET.Publish.Tests
+{
+    public class GivenThatWeWantToRunILLink : SdkTest
+    {
+        public GivenThatWeWantToRunILLink(ITestOutputHelper log) : base(log)
+        {
+        }
+
+        [Theory]
+        [InlineData("netcoreapp3.0")]
+        public void ILLink_only_runs_when_switch_is_enabled(string targetFramework)
+        {
+            var projectName = "HelloWorld";
+            var referenceProjectName = "ClassLib";
+            var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
+
+            var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
+            var testAsset = _testAssetsManager.CreateTestProject(testProject)
+                .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
+
+            var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true").Should().Pass();
+
+            var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var linkedDirectory = Path.Combine(intermediateDirectory, "linked");
+
+            Directory.Exists(linkedDirectory).Should().BeFalse();
+
+            var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
+            var unusedDll = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+
+            // Linker inputs are kept, including unused assemblies
+            File.Exists(publishedDll).Should().BeTrue();
+            File.Exists(unusedDll).Should().BeTrue();
+        }
+
+        [Theory]
+        [InlineData("netcoreapp3.0")]
+        public void ILLink_runs_and_creates_linked_app(string targetFramework)
+        {
+            var projectName = "HelloWorld";
+            var referenceProjectName = "ClassLib";
+            var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
+
+            var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
+            var testAsset = _testAssetsManager.CreateTestProject(testProject)
+                .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
+
+            var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+
+            var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var linkedDirectory = Path.Combine(intermediateDirectory, "linked");
+
+            Directory.Exists(linkedDirectory).Should().BeTrue();
+
+            var linkedDll = Path.Combine(linkedDirectory, $"{projectName}.dll");
+            var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
+            var unusedDll = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+
+            // Intermediate assembly is kept by linker and published, but not unused assemblies
+            File.Exists(linkedDll).Should().BeTrue();
+            File.Exists(publishedDll).Should().BeTrue();
+            File.Exists(unusedDll).Should().BeFalse();
+
+            var depsFile = Path.Combine(publishDirectory, $"{projectName}.deps.json");
+            DoesDepsFileHaveAssembly(depsFile, referenceProjectName).Should().BeFalse();
+        }
+
+        [Theory]
+        [InlineData("netcoreapp3.0")]
+        public void ILLink_accepts_root_descriptor(string targetFramework)
+        {
+            var projectName = "HelloWorld";
+            var referenceProjectName = "ClassLib";
+            var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
+
+            var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
+            var testAsset = _testAssetsManager.CreateTestProject(testProject)
+                .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
+
+            var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true",
+                                   $"/p:LinkerRootDescriptors={referenceProjectName}.xml").Should().Pass();
+
+            var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
+            var unusedDll = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+
+            // With root descriptor, linker keeps specified roots but removes unused methods
+            File.Exists(publishedDll).Should().BeTrue();
+            File.Exists(unusedDll).Should().BeTrue();
+            DoesImageHaveMethod(unusedDll, "UnusedMethod").Should().BeFalse();
+            DoesImageHaveMethod(unusedDll, "UnusedMethodToRoot").Should().BeTrue();
+        }
+
+        [Theory]
+        [InlineData("netcoreapp3.0")]
+        public void ILLink_runs_incrementally(string targetFramework)
+        {
+            var projectName = "HelloWorld";
+            var referenceProjectName = "ClassLib";
+            var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
+
+            var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
+            var testAsset = _testAssetsManager.CreateTestProject(testProject)
+                .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
+
+            var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
+
+            var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var linkedDirectory = Path.Combine(intermediateDirectory, "linked");
+
+            var linkSemaphore = Path.Combine(intermediateDirectory, "Link.semaphore");
+
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            DateTime semaphoreFirstModifiedTime = File.GetLastWriteTimeUtc(linkSemaphore);
+
+            WaitForUtcNowToAdvance();
+
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            DateTime semaphoreSecondModifiedTime = File.GetLastWriteTimeUtc(linkSemaphore);
+
+            semaphoreFirstModifiedTime.Should().Be(semaphoreSecondModifiedTime);
+        }
+
+        [Theory]
+        [InlineData("netcoreapp3.0")]
+        public void ILLink_does_not_include_leftover_artifacts_on_second_run(string targetFramework)
+        {
+            var projectName = "HelloWorld";
+            var referenceProjectName = "ClassLib";
+            var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
+
+            var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
+            var testAsset = _testAssetsManager.CreateTestProject(testProject)
+                .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
+
+            var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
+
+            var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
+            var linkedDirectory = Path.Combine(intermediateDirectory, "linked");
+
+            var linkSemaphore = Path.Combine(intermediateDirectory, "Link.semaphore");
+
+            // Link, keeping classlib
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true",
+                                   $"/p:LinkerRootDescriptors={referenceProjectName}.xml").Should().Pass();
+            var publishedDllKeptFirstTimeOnly = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+            var linkedDllKeptFirstTimeOnly = Path.Combine(linkedDirectory, $"{referenceProjectName}.dll");
+            File.Exists(linkedDllKeptFirstTimeOnly).Should().BeTrue();
+            File.Exists(publishedDllKeptFirstTimeOnly).Should().BeTrue();
+
+            // Delete kept dll from publish output (works around lack of incremental publish)
+            File.Delete(publishedDllKeptFirstTimeOnly);
+
+            // Modify input timestamp to force a re-build and re-link
+            WaitForUtcNowToAdvance();
+            File.SetLastWriteTimeUtc(Path.Combine(testAsset.TestRoot, testProject.Name, $"{projectName}.cs"), DateTime.UtcNow);
+
+            // Link, discarding classlib
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            File.Exists(linkedDllKeptFirstTimeOnly).Should().BeFalse();
+            File.Exists(publishedDllKeptFirstTimeOnly).Should().BeFalse();
+
+            // "linked" intermediate directory does not pollute the publish output
+            Directory.Exists(Path.Combine(publishDirectory, "linked")).Should().BeFalse();
+        }
+
+        [Theory]
+        [InlineData("netcoreapp3.0")]
+        public void ILLink_runs_on_portable_app(string targetFramework)
+        {
+            var projectName = "HelloWorld";
+            var referenceProjectName = "ClassLib";
+
+            var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
+            var testAsset = _testAssetsManager.CreateTestProject(testProject)
+                .Restore(Log, testProject.Name);
+
+            var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
+            publishCommand.Execute("/p:LinkDuringPublish=true").Should().Pass();
+
+            var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework).FullName;
+            var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework).FullName;
+            var linkedDirectory = Path.Combine(intermediateDirectory, "linked");
+
+            Directory.Exists(linkedDirectory).Should().BeTrue();
+
+            var linkedDll = Path.Combine(linkedDirectory, $"{projectName}.dll");
+            var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
+            var unusedDll = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+
+            File.Exists(linkedDll).Should().BeTrue();
+            File.Exists(publishedDll).Should().BeTrue();
+            File.Exists(unusedDll).Should().BeFalse();
+
+            var depsFile = Path.Combine(publishDirectory, $"{projectName}.deps.json");
+            DoesDepsFileHaveAssembly(depsFile, referenceProjectName).Should().BeFalse();
+        }
+
+        private static bool DoesImageHaveMethod(string path, string methodNameToCheck)
+        {
+            using (FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read))
+            using (var peReader = new PEReader(fs))
+            {
+                var metadataReader = peReader.GetMetadataReader();
+                foreach (var handle in metadataReader.MethodDefinitions)
+                {
+                    var methodDefinition = metadataReader.GetMethodDefinition(handle);
+                    string methodName = metadataReader.GetString(methodDefinition.Name);
+                    if (methodName == methodNameToCheck)
+                        return true;
+                }
+            }
+            return false;
+        }
+
+        private static bool DoesDepsFileHaveAssembly(string depsFilePath, string assemblyName)
+        {
+            DependencyContext dependencyContext;
+            using (var fs = File.OpenRead(depsFilePath))
+            {
+                dependencyContext = new DependencyContextJsonReader().Read(fs);
+            }
+
+            var runtimeLibrary = dependencyContext.RuntimeLibraries.Single(l => l.Name == assemblyName);
+            var runtimeFiles = runtimeLibrary.RuntimeAssemblyGroups.SelectMany(rag => rag.RuntimeFiles).ToList();
+            return runtimeFiles.Any();
+        }
+
+        private TestProject CreateTestProjectForILLinkTesting(string targetFramework, string mainProjectName, string referenceProjectName)
+        {
+            var referenceProject = new TestProject()
+            {
+                Name = referenceProjectName,
+                TargetFrameworks = targetFramework,
+                IsSdkProject = true
+            };
+            referenceProject.SourceFiles[$"{referenceProjectName}.cs"] = @"
+using System;
+public class ClassLib
+{
+    public void UnusedMethod()
+    {
+    }
+
+    public void UnusedMethodToRoot()
+    {
+    }
+}
+";
+
+            var testProject = new TestProject()
+            {
+                Name = mainProjectName,
+                TargetFrameworks = targetFramework,
+                IsSdkProject = true,
+                ReferencedProjects = { referenceProject }
+            };
+            testProject.SourceFiles[$"{mainProjectName}.cs"] = @"
+using System;
+public class Program
+{
+    public static void Main()
+    {
+        Console.WriteLine(""Hello world"");
+    }
+}
+";
+
+            testProject.SourceFiles[$"{referenceProjectName}.xml"] = $@"
+<linker>
+  <assembly fullname=""{referenceProjectName}"">
+    <type fullname=""ClassLib"">
+      <method name=""UnusedMethodToRoot"" />
+    </type>
+  </assembly>
+</linker>
+";
+
+            return testProject;
+        }
+    }
+}

From e3262fc30d17bb25475bec2e6c8485aedfa14862 Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Tue, 16 Apr 2019 13:06:19 -0700
Subject: [PATCH 2/6] Enable and test deps file trimming

Deps file trimming doesn't work on ProjectReferences, so this changes
the referenced test project to be a PackageReference.

We also disable use of the build dependency file when linking, as the
publish dependency file needs to be generated based on what the linker
decided to remove.
---
 .../targets/Microsoft.NET.ILLink.targets      | 15 ++++--
 .../targets/Microsoft.NET.Publish.targets     |  5 +-
 .../GivenThatWeWantToRunILLink.cs             | 48 +++++++++++++++----
 3 files changed, 51 insertions(+), 17 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
index cb692865217f..451548d21dfb 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
@@ -46,12 +46,17 @@ Copyright (c) .NET Foundation. All rights reserved.
       <ResolvedFileToPublish Include="@(_LinkedResolvedFileToPublish)" />
     </ItemGroup>
 
-    <!-- Use _PublishConflictPackageFiles to remove assemblies from
-         the deps file. This will change with the fix to
-         https://github.com/dotnet/sdk/issues/3010. -->
+    <!-- Remove assemblies from inputs to GenerateDepsFile. See
+         https://github.com/dotnet/sdk/pull/3086. -->
     <ItemGroup>
       <_RemovedManagedAssemblies Include="@(_ManagedAssembliesToLink)" Condition="!Exists('$(IntermediateLinkDir)/%(Filename)%(Extension)')" />
-      <_PublishConflictPackageFiles Include="@(_RemovedManagedAssemblies)" />
+
+      <ResolvedCompileFileDefinitions Remove="@(_RemovedManagedAssemblies)" />
+      <NativeCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
+      <ResourceCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
+      <RuntimeCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
+      <RuntimeTargetsCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
+      <RuntimePackAsset Remove="@(_RemovedManagedAssemblies)" />
     </ItemGroup>
 
   </Target>
@@ -72,8 +77,8 @@ Copyright (c) .NET Foundation. All rights reserved.
            Outputs="$(_LinkSemaphore)">
 
      <Delete Files="@(_LinkedResolvedFileToPublishCandidates)" />
-     <!-- TODO: add ReferenceAssemblyPaths="@(ReferencePath)" -->
      <ILLink AssemblyPaths="@(_ManagedAssembliesToLink)"
+             ReferenceAssemblyPaths="@(ReferencePath)"
              RootAssemblyNames="@(IntermediateAssembly->'%(Filename)')"
              RootDescriptorFiles="@(LinkerRootDescriptors)"
              OutputDirectory="$(IntermediateLinkDir)"
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
index a169bf76ce8e..a51f686351a3 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
@@ -744,11 +744,12 @@ Copyright (c) .NET Foundation. All rights reserved.
           DependsOnTargets="_ComputeExcludeFromPublishPackageReferences;
                             _ParseTargetManifestFiles">
 
-    <!-- If there are no excluded packages or runtime store packages, then we can reuse the deps file from the build, -->
+    <!-- If there are no excluded packages or runtime store packages, and we are not linking, then we can reuse the deps file from the build, -->
     <PropertyGroup>
       <_UseBuildDependencyFile Condition="'@(_ExcludeFromPublishPackageReference)' == '' and
                                           '@(RuntimeStorePackages)' == '' and
-                                          '$(PreserveStoreLayout)' != 'true'">true</_UseBuildDependencyFile>
+                                          '$(PreserveStoreLayout)' != 'true' and
+                                          '$(LinkDuringPublish)' != 'true'">true</_UseBuildDependencyFile>
     </PropertyGroup>
 
   </Target>
diff --git a/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs b/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
index 5718c9e0b2b8..afdbebe1f57e 100644
--- a/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
+++ b/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
@@ -25,7 +25,7 @@ public GivenThatWeWantToRunILLink(ITestOutputHelper log) : base(log)
         public void ILLink_only_runs_when_switch_is_enabled(string targetFramework)
         {
             var projectName = "HelloWorld";
-            var referenceProjectName = "ClassLib";
+            var referenceProjectName = "ClassLibForILLink";
             var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
 
             var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
@@ -43,10 +43,16 @@ public void ILLink_only_runs_when_switch_is_enabled(string targetFramework)
 
             var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
             var unusedDll = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+            var unusedFrameworkDll = Path.Combine(publishDirectory, $"{unusedFrameworkAssembly}.dll");
 
             // Linker inputs are kept, including unused assemblies
             File.Exists(publishedDll).Should().BeTrue();
             File.Exists(unusedDll).Should().BeTrue();
+            File.Exists(unusedFrameworkDll).Should().BeTrue();
+
+            var depsFile = Path.Combine(publishDirectory, $"{projectName}.deps.json");
+            DoesDepsFileHaveAssembly(depsFile, referenceProjectName).Should().BeTrue();
+            DoesDepsFileHaveAssembly(depsFile, unusedFrameworkAssembly).Should().BeTrue();
         }
 
         [Theory]
@@ -54,7 +60,7 @@ public void ILLink_only_runs_when_switch_is_enabled(string targetFramework)
         public void ILLink_runs_and_creates_linked_app(string targetFramework)
         {
             var projectName = "HelloWorld";
-            var referenceProjectName = "ClassLib";
+            var referenceProjectName = "ClassLibForILLink";
             var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
 
             var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
@@ -73,14 +79,18 @@ public void ILLink_runs_and_creates_linked_app(string targetFramework)
             var linkedDll = Path.Combine(linkedDirectory, $"{projectName}.dll");
             var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
             var unusedDll = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
+            var unusedFrameworkDll = Path.Combine(publishDirectory, $"{unusedFrameworkAssembly}.dll");
 
             // Intermediate assembly is kept by linker and published, but not unused assemblies
             File.Exists(linkedDll).Should().BeTrue();
             File.Exists(publishedDll).Should().BeTrue();
             File.Exists(unusedDll).Should().BeFalse();
+            File.Exists(unusedFrameworkDll).Should().BeFalse();
 
             var depsFile = Path.Combine(publishDirectory, $"{projectName}.deps.json");
+            DoesDepsFileHaveAssembly(depsFile, projectName).Should().BeTrue();
             DoesDepsFileHaveAssembly(depsFile, referenceProjectName).Should().BeFalse();
+            DoesDepsFileHaveAssembly(depsFile, unusedFrameworkAssembly).Should().BeFalse();
         }
 
         [Theory]
@@ -88,7 +98,7 @@ public void ILLink_runs_and_creates_linked_app(string targetFramework)
         public void ILLink_accepts_root_descriptor(string targetFramework)
         {
             var projectName = "HelloWorld";
-            var referenceProjectName = "ClassLib";
+            var referenceProjectName = "ClassLibForILLink";
             var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
 
             var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
@@ -115,7 +125,7 @@ public void ILLink_accepts_root_descriptor(string targetFramework)
         public void ILLink_runs_incrementally(string targetFramework)
         {
             var projectName = "HelloWorld";
-            var referenceProjectName = "ClassLib";
+            var referenceProjectName = "ClassLibForILLink";
             var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
 
             var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
@@ -146,7 +156,7 @@ public void ILLink_runs_incrementally(string targetFramework)
         public void ILLink_does_not_include_leftover_artifacts_on_second_run(string targetFramework)
         {
             var projectName = "HelloWorld";
-            var referenceProjectName = "ClassLib";
+            var referenceProjectName = "ClassLibForILLink";
             var rid = EnvironmentInfo.GetCompatibleRid(targetFramework);
 
             var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
@@ -190,7 +200,7 @@ public void ILLink_does_not_include_leftover_artifacts_on_second_run(string targ
         public void ILLink_runs_on_portable_app(string targetFramework)
         {
             var projectName = "HelloWorld";
-            var referenceProjectName = "ClassLib";
+            var referenceProjectName = "ClassLibForILLink";
 
             var testProject = CreateTestProjectForILLinkTesting(targetFramework, projectName, referenceProjectName);
             var testAsset = _testAssetsManager.CreateTestProject(testProject)
@@ -214,6 +224,7 @@ public void ILLink_runs_on_portable_app(string targetFramework)
             File.Exists(unusedDll).Should().BeFalse();
 
             var depsFile = Path.Combine(publishDirectory, $"{projectName}.deps.json");
+            DoesDepsFileHaveAssembly(depsFile, projectName).Should().BeTrue();
             DoesDepsFileHaveAssembly(depsFile, referenceProjectName).Should().BeFalse();
         }
 
@@ -242,9 +253,21 @@ private static bool DoesDepsFileHaveAssembly(string depsFilePath, string assembl
                 dependencyContext = new DependencyContextJsonReader().Read(fs);
             }
 
-            var runtimeLibrary = dependencyContext.RuntimeLibraries.Single(l => l.Name == assemblyName);
-            var runtimeFiles = runtimeLibrary.RuntimeAssemblyGroups.SelectMany(rag => rag.RuntimeFiles).ToList();
-            return runtimeFiles.Any();
+            return dependencyContext.RuntimeLibraries.Any(l =>
+                l.RuntimeAssemblyGroups.Any(rag =>
+                    rag.AssetPaths.Any(f =>
+                        Path.GetFileName(f) == $"{assemblyName}.dll")));
+        }
+
+        static string unusedFrameworkAssembly = "System.IO";
+
+        private TestPackageReference GetPackageReference(TestProject project)
+        {
+            var asset = _testAssetsManager.CreateTestProject(project, project.Name).Restore(Log, project.Name);
+            var pack = new PackCommand(Log, Path.Combine(asset.TestRoot, project.Name));
+            pack.Execute().Should().Pass();
+
+            return new TestPackageReference(project.Name, "1.0.0", pack.GetNuGetPackage(project.Name));
         }
 
         private TestProject CreateTestProjectForILLinkTesting(string targetFramework, string mainProjectName, string referenceProjectName)
@@ -269,13 +292,18 @@ public void UnusedMethodToRoot()
 }
 ";
 
+            var packageReference = GetPackageReference(referenceProject);
+
             var testProject = new TestProject()
             {
                 Name = mainProjectName,
                 TargetFrameworks = targetFramework,
                 IsSdkProject = true,
-                ReferencedProjects = { referenceProject }
+                PackageReferences = { packageReference }
             };
+
+            testProject.AdditionalProperties.Add("RestoreAdditionalProjectSources", Path.GetDirectoryName(packageReference.NupkgPath));
+
             testProject.SourceFiles[$"{mainProjectName}.cs"] = @"
 using System;
 public class Program

From 075b1374f312ee1c79bbcbeab946606bca81a2e8 Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Wed, 17 Apr 2019 14:51:45 -0700
Subject: [PATCH 3/6] Support old deps generation logic

---
 .../targets/Microsoft.NET.ILLink.targets                    | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
index 451548d21dfb..fce82e1a120c 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
@@ -57,8 +57,14 @@ Copyright (c) .NET Foundation. All rights reserved.
       <RuntimeCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
       <RuntimeTargetsCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
       <RuntimePackAsset Remove="@(_RemovedManagedAssemblies)" />
+
+      <!-- Also remove them from the old deps file generation logic,
+           until https://github.com/dotnet/sdk/issues/3098 is
+           fixed. -->
+      <_PublishConflictPackageFiles Include="@(_RemovedManagedAssemblies)" />
     </ItemGroup>
 
+
   </Target>
 
 

From 1c98c83f414d13ca13467c0d6255f148ee4d8098 Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Wed, 17 Apr 2019 15:31:41 -0700
Subject: [PATCH 4/6] Update property names and respond to PR feedback

The current public-facing linker properties are now:
- PublishTrimmed
- TrimmerRootDescriptors

The IL transform extension point has been named ILTransformForPublish,
to make it clear that it only runs on publish.

This also enables incremental build for project file changes, and lets
the linker run on projects targeting .NETStandard.
---
 .../targets/Microsoft.NET.ILLink.targets      | 20 +++++++++----------
 .../targets/Microsoft.NET.Publish.targets     | 14 ++++++-------
 .../GivenThatWeWantToRunILLink.cs             | 18 ++++++++---------
 3 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
index fce82e1a120c..4a9d19f8dd35 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
@@ -14,28 +14,28 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Import Project="Sdk.props" Sdk="ILLink.Tasks" />
 
   <PropertyGroup>
-    <ILTransformDependsOn>$(ILTransformDependsOn);ILLink</ILTransformDependsOn>
+    <ILTransformForPublishDependsOn>$(ILTransformForPublishDependsOn);_ILLink</ILTransformForPublishDependsOn>
     <IntermediateLinkDir Condition=" '$(IntermediateLinkDir)' == '' ">$(IntermediateOutputPath)linked</IntermediateLinkDir>
     <!-- Used to enable incremental build for the linker target. -->
     <_LinkSemaphore>$(IntermediateOutputPath)Link.semaphore</_LinkSemaphore>
   </PropertyGroup>
 
   <ItemGroup>
-    <LinkerRootDescriptors Include="$(LinkerRootDescriptors)" />
+    <TrimmerRootDescriptors Include="$(TrimmerRootDescriptors)" />
   </ItemGroup>
 
   <!--
     ============================================================
-                     ILLink
+                     _ILLink
 
     Replace the files to be published with versions that have been
     passed through the linker. Also prevent removed files from being
     included in the generated deps.json.
     ============================================================
     -->
-  <Target Name="ILLink"
-          Condition=" '$(LinkDuringPublish)' == 'true' "
-          DependsOnTargets="RunILLink">
+  <Target Name="_ILLink"
+          Condition=" '$(PublishTrimmed)' == 'true' "
+          DependsOnTargets="_RunILLink">
 
     <!-- For now, use ResolvedFileToPublish as input/output. This
          should go away in favor of a well-defined set of runtime
@@ -70,23 +70,23 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <!--
     ============================================================
-                     RunILLink
+                     _RunILLink
 
     Execute the linker. This target runs incrementally, only executing
     if the output semaphore file is out of date with respect to the inputs.
     ============================================================
     -->
    <UsingTask TaskName="ILLink" AssemblyFile="$(ILLinkTasksAssembly)" />
-   <Target Name="RunILLink"
+   <Target Name="_RunILLink"
            DependsOnTargets="_ComputeManagedAssembliesToLink"
-           Inputs="@(_ManagedAssembliesToLink);@(LinkerRootDescriptors);@(ReferencePath)"
+           Inputs="$(MSBuildAllProjects);@(_ManagedAssembliesToLink);@(TrimmerRootDescriptors);@(ReferencePath)"
            Outputs="$(_LinkSemaphore)">
 
      <Delete Files="@(_LinkedResolvedFileToPublishCandidates)" />
      <ILLink AssemblyPaths="@(_ManagedAssembliesToLink)"
              ReferenceAssemblyPaths="@(ReferencePath)"
              RootAssemblyNames="@(IntermediateAssembly->'%(Filename)')"
-             RootDescriptorFiles="@(LinkerRootDescriptors)"
+             RootDescriptorFiles="@(TrimmerRootDescriptors)"
              OutputDirectory="$(IntermediateLinkDir)"
              ExtraArgs="$(ExtraLinkerArgs) --skip-unresolved true" />
 
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
index a51f686351a3..77420768497e 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
@@ -107,7 +107,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
   <Target Name="ComputeAndCopyFilesToPublishDirectory"
           DependsOnTargets="ComputeFilesToPublish;
-                            ILTransform;
+                            ILTransformForPublish;
                             CreateReadyToRunImages;
                             CopyFilesToPublishDirectory" />
 
@@ -199,14 +199,14 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <!--
     ============================================================
-                                        ILTransform
+                                        ILTransformForPublish
 
-    Extension point for IL transformations.
+    Extension point for IL transformations that happen on publish.
     ============================================================
     -->
-  <Target Name="ILTransform"
-          Condition="'$(_TargetFrameworkVersionWithoutV)' >= '3.0' And '$(TargetFrameworkIdentifier)' == '.NETCoreApp'"
-          DependsOnTargets="$(ILTransformDependsOn)" />
+  <Target Name="ILTransformForPublish"
+          Condition="'$(_TargetFrameworkVersionWithoutV)' >= '3.0' And ( '$(TargetFrameworkIdentifier)' == '.NETCoreApp' Or '$(TargetFrameworkIdentifier)' == '.NETStandard' )"
+          DependsOnTargets="$(ILTransformForPublishDependsOn)" />
 
   <!--
     ============================================================
@@ -749,7 +749,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_UseBuildDependencyFile Condition="'@(_ExcludeFromPublishPackageReference)' == '' and
                                           '@(RuntimeStorePackages)' == '' and
                                           '$(PreserveStoreLayout)' != 'true' and
-                                          '$(LinkDuringPublish)' != 'true'">true</_UseBuildDependencyFile>
+                                          '$(PublishTrimmed)' != 'true'">true</_UseBuildDependencyFile>
     </PropertyGroup>
 
   </Target>
diff --git a/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs b/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
index afdbebe1f57e..add279e0a81e 100644
--- a/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
+++ b/src/Tests/Microsoft.NET.Publish.Tests/GivenThatWeWantToRunILLink.cs
@@ -68,7 +68,7 @@ public void ILLink_runs_and_creates_linked_app(string targetFramework)
                 .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
 
             var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
-            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:PublishTrimmed=true").Should().Pass();
 
             var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
             var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
@@ -106,8 +106,8 @@ public void ILLink_accepts_root_descriptor(string targetFramework)
                 .Restore(Log, testProject.Name, args: $"/p:RuntimeIdentifier={rid}");
 
             var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
-            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true",
-                                   $"/p:LinkerRootDescriptors={referenceProjectName}.xml").Should().Pass();
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:PublishTrimmed=true",
+                                   $"/p:TrimmerRootDescriptors={referenceProjectName}.xml").Should().Pass();
 
             var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework, runtimeIdentifier: rid).FullName;
             var publishedDll = Path.Combine(publishDirectory, $"{projectName}.dll");
@@ -140,12 +140,12 @@ public void ILLink_runs_incrementally(string targetFramework)
 
             var linkSemaphore = Path.Combine(intermediateDirectory, "Link.semaphore");
 
-            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:PublishTrimmed=true").Should().Pass();
             DateTime semaphoreFirstModifiedTime = File.GetLastWriteTimeUtc(linkSemaphore);
 
             WaitForUtcNowToAdvance();
 
-            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:PublishTrimmed=true").Should().Pass();
             DateTime semaphoreSecondModifiedTime = File.GetLastWriteTimeUtc(linkSemaphore);
 
             semaphoreFirstModifiedTime.Should().Be(semaphoreSecondModifiedTime);
@@ -172,8 +172,8 @@ public void ILLink_does_not_include_leftover_artifacts_on_second_run(string targ
             var linkSemaphore = Path.Combine(intermediateDirectory, "Link.semaphore");
 
             // Link, keeping classlib
-            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true",
-                                   $"/p:LinkerRootDescriptors={referenceProjectName}.xml").Should().Pass();
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:PublishTrimmed=true",
+                                   $"/p:TrimmerRootDescriptors={referenceProjectName}.xml").Should().Pass();
             var publishedDllKeptFirstTimeOnly = Path.Combine(publishDirectory, $"{referenceProjectName}.dll");
             var linkedDllKeptFirstTimeOnly = Path.Combine(linkedDirectory, $"{referenceProjectName}.dll");
             File.Exists(linkedDllKeptFirstTimeOnly).Should().BeTrue();
@@ -187,7 +187,7 @@ public void ILLink_does_not_include_leftover_artifacts_on_second_run(string targ
             File.SetLastWriteTimeUtc(Path.Combine(testAsset.TestRoot, testProject.Name, $"{projectName}.cs"), DateTime.UtcNow);
 
             // Link, discarding classlib
-            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:LinkDuringPublish=true").Should().Pass();
+            publishCommand.Execute($"/p:RuntimeIdentifier={rid}", $"/p:SelfContained=true", "/p:PublishTrimmed=true").Should().Pass();
             File.Exists(linkedDllKeptFirstTimeOnly).Should().BeFalse();
             File.Exists(publishedDllKeptFirstTimeOnly).Should().BeFalse();
 
@@ -207,7 +207,7 @@ public void ILLink_runs_on_portable_app(string targetFramework)
                 .Restore(Log, testProject.Name);
 
             var publishCommand = new PublishCommand(Log, Path.Combine(testAsset.TestRoot, testProject.Name));
-            publishCommand.Execute("/p:LinkDuringPublish=true").Should().Pass();
+            publishCommand.Execute("/p:PublishTrimmed=true").Should().Pass();
 
             var publishDirectory = publishCommand.GetOutputDirectory(targetFramework: targetFramework).FullName;
             var intermediateDirectory = publishCommand.GetIntermediateDirectory(targetFramework: targetFramework).FullName;

From e475c44874962fa36f464330101b324d9d3404bc Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Thu, 18 Apr 2019 16:48:21 -0700
Subject: [PATCH 5/6] Respond to PR feedback

- Ensure trailing slash in linker output directory
- Disable old deps file generation logic
- Don't support netstandard
- ExtraLinkerArgs -> _ExtraTrimmerArgs
- Remove ILTransformForPublish extension point
---
 .../targets/Microsoft.NET.ILLink.targets      | 26 +++++++++----------
 .../targets/Microsoft.NET.Publish.targets     | 13 +---------
 2 files changed, 14 insertions(+), 25 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
index 4a9d19f8dd35..0d55fbe47b65 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
@@ -15,9 +15,13 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <PropertyGroup>
     <ILTransformForPublishDependsOn>$(ILTransformForPublishDependsOn);_ILLink</ILTransformForPublishDependsOn>
-    <IntermediateLinkDir Condition=" '$(IntermediateLinkDir)' == '' ">$(IntermediateOutputPath)linked</IntermediateLinkDir>
+    <IntermediateLinkDir Condition=" '$(IntermediateLinkDir)' == '' ">$(IntermediateOutputPath)linked\</IntermediateLinkDir>
+    <IntermediateLinkDir Condition=" !HasTrailingSlash('$(IntermediateLinkDir)') ">$(IntermediateLinkDir)\</IntermediateLinkDir>
     <!-- Used to enable incremental build for the linker target. -->
     <_LinkSemaphore>$(IntermediateOutputPath)Link.semaphore</_LinkSemaphore>
+    <!-- Disable old deps file generation logic until
+         https://github.com/dotnet/sdk/issues/3098 is fixed. -->
+    <DepsFileGenerationMode>new</DepsFileGenerationMode>
   </PropertyGroup>
 
   <ItemGroup>
@@ -34,7 +38,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     ============================================================
     -->
   <Target Name="_ILLink"
-          Condition=" '$(PublishTrimmed)' == 'true' "
+          Condition=" '$(PublishTrimmed)' == 'true' And
+                      '$(_TargetFrameworkVersionWithoutV)' >= '3.0' And '$(TargetFrameworkIdentifier)' == '.NETCoreApp' "
           DependsOnTargets="_RunILLink">
 
     <!-- For now, use ResolvedFileToPublish as input/output. This
@@ -49,7 +54,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!-- Remove assemblies from inputs to GenerateDepsFile. See
          https://github.com/dotnet/sdk/pull/3086. -->
     <ItemGroup>
-      <_RemovedManagedAssemblies Include="@(_ManagedAssembliesToLink)" Condition="!Exists('$(IntermediateLinkDir)/%(Filename)%(Extension)')" />
+      <_RemovedManagedAssemblies Include="@(_ManagedAssembliesToLink)" Condition="!Exists('$(IntermediateLinkDir)%(Filename)%(Extension)')" />
 
       <ResolvedCompileFileDefinitions Remove="@(_RemovedManagedAssemblies)" />
       <NativeCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
@@ -57,14 +62,8 @@ Copyright (c) .NET Foundation. All rights reserved.
       <RuntimeCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
       <RuntimeTargetsCopyLocalItems Remove="@(_RemovedManagedAssemblies)" />
       <RuntimePackAsset Remove="@(_RemovedManagedAssemblies)" />
-
-      <!-- Also remove them from the old deps file generation logic,
-           until https://github.com/dotnet/sdk/issues/3098 is
-           fixed. -->
-      <_PublishConflictPackageFiles Include="@(_RemovedManagedAssemblies)" />
     </ItemGroup>
 
-
   </Target>
 
 
@@ -88,7 +87,7 @@ Copyright (c) .NET Foundation. All rights reserved.
              RootAssemblyNames="@(IntermediateAssembly->'%(Filename)')"
              RootDescriptorFiles="@(TrimmerRootDescriptors)"
              OutputDirectory="$(IntermediateLinkDir)"
-             ExtraArgs="$(ExtraLinkerArgs) --skip-unresolved true" />
+             ExtraArgs="$(_ExtraTrimmerArgs) --skip-unresolved true" />
 
      <Touch Files="$(_LinkSemaphore)" AlwaysCreate="true" />
 
@@ -100,8 +99,9 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     Compute the set of inputs to the linker. Currently this uses a
     heuristic to get the relevant input from ResolvedFileToPublish,
-    but in the future this should be replaced with the exact set of
-    runtime assemblies that will be in the deps file.
+    but with https://github.com/dotnet/sdk/issues/3109, this should be
+    replaced with the exact set of runtime assemblies that will be in
+    the deps file.
     ============================================================
     -->
   <UsingTask TaskName="ComputeManagedAssemblies" AssemblyFile="$(ILLinkTasksAssembly)" />
@@ -112,7 +112,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <ItemGroup>
       <_ManagedAssembliesToLink Remove="@(_ManagedResolvedFileToPublish->WithMetadataValue('AssetType', 'resources'))" />
-      <_LinkedResolvedFileToPublishCandidates Include="@(_ManagedAssembliesToLink->'$(IntermediateLinkDir)/%(Filename)%(Extension)')" />
+      <_LinkedResolvedFileToPublishCandidates Include="@(_ManagedAssembliesToLink->'$(IntermediateLinkDir)%(Filename)%(Extension)')" />
     </ItemGroup>
 
   </Target>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
index 77420768497e..e921a0f21fd8 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
@@ -107,7 +107,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
   <Target Name="ComputeAndCopyFilesToPublishDirectory"
           DependsOnTargets="ComputeFilesToPublish;
-                            ILTransformForPublish;
+                            _ILLink;
                             CreateReadyToRunImages;
                             CopyFilesToPublishDirectory" />
 
@@ -197,17 +197,6 @@ Copyright (c) .NET Foundation. All rights reserved.
     </Copy>
   </Target>
 
-  <!--
-    ============================================================
-                                        ILTransformForPublish
-
-    Extension point for IL transformations that happen on publish.
-    ============================================================
-    -->
-  <Target Name="ILTransformForPublish"
-          Condition="'$(_TargetFrameworkVersionWithoutV)' >= '3.0' And ( '$(TargetFrameworkIdentifier)' == '.NETCoreApp' Or '$(TargetFrameworkIdentifier)' == '.NETStandard' )"
-          DependsOnTargets="$(ILTransformForPublishDependsOn)" />
-
   <!--
     ============================================================
                                         CreateReadyToRunImages

From bdbe81c9f0da1349ea57325b25a9b1d668f1e7a1 Mon Sep 17 00:00:00 2001
From: Sven Boemer <sbomer@gmail.com>
Date: Thu, 18 Apr 2019 17:13:13 -0700
Subject: [PATCH 6/6] Remove left-over ILTransformForPublishDependsOn property

---
 .../targets/Microsoft.NET.ILLink.targets                         | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
index 0d55fbe47b65..bf6973b09d45 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.ILLink.targets
@@ -14,7 +14,6 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Import Project="Sdk.props" Sdk="ILLink.Tasks" />
 
   <PropertyGroup>
-    <ILTransformForPublishDependsOn>$(ILTransformForPublishDependsOn);_ILLink</ILTransformForPublishDependsOn>
     <IntermediateLinkDir Condition=" '$(IntermediateLinkDir)' == '' ">$(IntermediateOutputPath)linked\</IntermediateLinkDir>
     <IntermediateLinkDir Condition=" !HasTrailingSlash('$(IntermediateLinkDir)') ">$(IntermediateLinkDir)\</IntermediateLinkDir>
     <!-- Used to enable incremental build for the linker target. -->