Update CoreRT doc to include how to debug ILC using VSCode in non-win… (#2514)

* Update CoreRT doc to include how to debug ILC using VSCode in non-windows

* Automate some of the tasks and check in vscode .json files

* Simplify instructions

* Explains the magic and added a bit more coding annotations to make it looks better

* Change ILCompiler.csproj to output ILC.dll directly to be VS-code friendly

9 files changed, 125 insertions, 3 deletions

diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 000000000..46d40ef7b
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,27 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": ".NET Core Launch (console)",
+            "type": "coreclr",
+            "request": "launch",
+            "preLaunchTask": "",
+            "osx": {
+                "program": "${workspaceRoot}/bin/Product/OSX.x64.Debug/packaging/publish1/ilc.dll"
+            },
+            "linux": {
+                "program": "${workspaceRoot}/bin/Product/Linux.x64.Debug/packaging/publish1/ilc.dll"
+            },
+            "args": [],
+            "cwd": "${workspaceRoot}",
+            "stopAtEntry": false,
+            "externalConsole": false
+        },
+        {
+            "name": ".NET Core Attach",
+            "type": "coreclr",
+            "request": "attach",
+            "processId": "${command.pickProcess}"
+        }
+    ]
+}
\ No newline at end of file
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
new file mode 100644
index 000000000..3420cc476
--- /dev/null
+++ b/.vscode/tasks.json
@@ -0,0 +1,18 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "0.1.0",
+    "command": "${workspaceRoot}/build.sh",
+    "isShellCommand": false,
+    "args": [],
+    "tasks": [
+        {
+            "taskName": "build",
+            "args": [ ],
+            "isBuildCommand": true,
+            "showOutput": "silent",
+            "suppressTaskName" : true,
+            "problemMatcher": "$msCompile"
+        }
+    ]
+}
diff --git a/Documentation/README.md b/Documentation/README.md
index bcca1faeb..1f099ff2c 100644
--- a/Documentation/README.md
+++ b/Documentation/README.md
@@ -12,5 +12,6 @@ This is the repo for CoreRT, the .NET Core runtime optimized for AOT (Ahead of T
 - [Prerequisites for building](prerequisites-for-building.md)
 - [How to build and run from the Command Line](how-to-build-and-run-ilcompiler-in-console-shell-prompt.md)
 - [How to build and run from Visual Studio](how-to-build-and-run-ilcompiler-in-visual-studio-2015.md)
+- [How to build and run from VSCode](how-to-build-and-run-ilcompiler-in-vscode.md)
 - [How to run tests](how-to-run-tests.md)
 - [Cross Compilation for ARM on Linux](cross-building.md)
diff --git a/Documentation/how-to-build-and-run-ilcompiler-in-vscode.md b/Documentation/how-to-build-and-run-ilcompiler-in-vscode.md
new file mode 100644
index 000000000..df1f3fe9b
--- /dev/null
+++ b/Documentation/how-to-build-and-run-ilcompiler-in-vscode.md
@@ -0,0 +1,54 @@
+_Please ensure that [pre-requisites](prerequisites-for-building.md) are installed for a successful build of the repo._
+
+_Note_:
+
+* Instructions below assume ```~/corert``` is the repo root.
+
+# Setting up #
+
+Please make sure you have latest VS Code, C# extension, and .NET Core available. This guide is tested under C# 1.6.2 + VS Code 1.8.1 + CLI 1.0.0-preview4-004233.
+
+This guide assumes that your VS code workspace is set to the root of the repo. 
+
+# Running VS Code
+
+We've checked-in reasonable default ```launch.json``` and ```tasks.json``` under ```corert/.vscode``` directory. You only need to run vscode form corert root:
+
+```
+code ~/corert
+```
+
+And then press SHIFT+COMMAND+B to start the build.
+
+# Debugging ILC.exe using .NET Core Debugger #
+
+Go to the debug pane and click Debug, choose .NET Core as the environment. If needed, you can change program property in launch.json (the gear button) to point to a different flavor of ilc:
+
+```json
+            "osx": {
+                "program": "${workspaceRoot}/bin/Product/OSX.x64.Debug/packaging/publish1/ilc.dll"
+            },
+            "linux": {
+                "program": "${workspaceRoot}/bin/Product/Linux.x64.Debug/packaging/publish1/ilc.dll"
+            },
+```
+
+By default we've disabled automatic build before debug. If you want to change that, you can change the ```preLaunchTask``` property to ```"build"```. But this is not currently recommended.
+
+# Getting ILC response files
+
+A ```.ilc.rsp``` file path can be easily obtained from a .NET core project that you want to debug by following command:
+
+```
+dotnet build /t:LinkNative /t:Rebuild /v:Detailed | grep ".ilc.rsp"
+```
+
+Once you have the ilc path, you can change ```launch.json``` accordingly:
+
+```json
+            "args": ["@obj/Debug/netcoreapp1.0/native/<netcore_app_name>.ilc.rsp"],
+            "cwd": "<netcore_app_root_folder>",
+```
+
+* ```args``` - the argument to ILC
+* ```cwd``` - the current directory where ILC is running. You can set it to the .NET Core project root. 
diff --git a/src/BuildIntegration/Microsoft.NETCore.Native.targets b/src/BuildIntegration/Microsoft.NETCore.Native.targets
index 9d1325eff..c45f6636f 100644
--- a/src/BuildIntegration/Microsoft.NETCore.Native.targets
+++ b/src/BuildIntegration/Microsoft.NETCore.Native.targets
@@ -91,7 +91,7 @@ See the LICENSE file in the project root for more information.
       <TestHost Condition="'$(OS)' != 'Windows_NT'">corerun</TestHost>
     </PropertyGroup>
 
-    <Exec Command="&quot;$(IlcPath)\$(TestHost)&quot; &quot;$(IlcPath)\ilc.exe&quot; @&quot;$(NativeIntermediateOutputPath)%(ManagedBinary.Filename).ilc.rsp&quot;">
+    <Exec Command="&quot;$(IlcPath)\$(TestHost)&quot; &quot;$(IlcPath)\ilc.dll&quot; @&quot;$(NativeIntermediateOutputPath)%(ManagedBinary.Filename).ilc.rsp&quot;">
     </Exec>
 
   </Target>
diff --git a/src/ILCompiler/src/ILCompiler.csproj b/src/ILCompiler/src/ILCompiler.csproj
index 1121a50ee..3ffc7651a 100644
--- a/src/ILCompiler/src/ILCompiler.csproj
+++ b/src/ILCompiler/src/ILCompiler.csproj
@@ -7,6 +7,10 @@
     <ProjectGuid>{DD5B6BAA-D41A-4A6E-9E7D-83060F394B10}</ProjectGuid>
     <OutputType>Exe</OutputType>
     <RootNamespace>ILCompiler</RootNamespace>
+    <!-- This is needed for VS Code debugging for ILC - it only likes DLL extension -->
+    <!-- This also aligns with .NET Core applications model -->
+    <!-- Note that we can't change the OutputType to be library - there is no entry point -->
+    <TargetExt>.dll</TargetExt>
     <AssemblyName>ilc</AssemblyName>
     <DefaultLanguage>en-US</DefaultLanguage>
     <FileAlignment>512</FileAlignment>
@@ -44,6 +48,10 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="project.json" />
+    <!-- This is needed for VS Code debugging for ILC -->
+    <Content Include="ilc.runtimeconfig.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\ILCompiler.Compiler\src\ILCompiler.Compiler.csproj">
diff --git a/src/ILCompiler/src/ilc.runtimeconfig.json b/src/ILCompiler/src/ilc.runtimeconfig.json
new file mode 100755
index 000000000..d0437745b
--- /dev/null
+++ b/src/ILCompiler/src/ilc.runtimeconfig.json
@@ -0,0 +1,8 @@
+{
+  "runtimeOptions": {
+    "framework": {
+      "name": "Microsoft.NETCore.App",
+      "version": "1.0.1"
+    }
+  }
+}
\ No newline at end of file
diff --git a/src/Test.CoreLib/readme.md b/src/Test.CoreLib/readme.md
index d05eca4ff..878302f80 100644
--- a/src/Test.CoreLib/readme.md
+++ b/src/Test.CoreLib/readme.md
@@ -14,7 +14,7 @@ csc /noconfig /nostdlib Program.cs /r:<repo_root>\bin\Product\Windows_NT.x64.Deb
 
 2. Compile the IL with ILC
 
-Use ilc.exe that was built with the repo to compile the program.
+Use ilc.dll that was built with the repo to compile the program.
 
 ```
 ilc repro.exe -o:repro.obj -r:<repo_root>\bin\Product\Windows_NT.x64.Debug\Test.CoreLib\Test.CoreLib.dll --systemmodule Test.CoreLib
diff --git a/src/packaging/packages.targets b/src/packaging/packages.targets
index f362e52cd..00b505047 100644
--- a/src/packaging/packages.targets
+++ b/src/packaging/packages.targets
@@ -33,7 +33,7 @@
         </PropertyGroup>
         <ItemGroup>
             <!-- IL.Compiler target files -->
-            <ILCompilerFiles Include="ilc.exe" />
+            <ILCompilerFiles Include="ilc.dll" />
             <ILCompilerFiles Include="ILCompiler.Compiler.dll" />
             <ILCompilerFiles Include="ILCompiler.DependencyAnalysisFramework.dll" />
             <ILCompilerFiles Include="ILCompiler.MetadataTransform.dll" />
@@ -74,6 +74,12 @@
             <ILCompilerBinPlace Include="@(ILCompilerContentFiles)">
                 <Text><![CDATA[        <file src="src/%(Identity)" target="runtimes/$(NuPkgRid)/native/%(Filename)%(Extension)" /> ]]></Text>
             </ILCompilerBinPlace>
+ 
+            <!-- This is needed for VS Code debugging for ILC -->
+            <ILCompilerJsonContentFiles Include="ilc.runtimeconfig.json" />
+            <ILCompilerBinPlace Include="@(ILCompilerJsonContentFiles)">
+                <Text><![CDATA[        <file src="src/ILCompiler/src/%(Identity)" target="runtimes/$(NuPkgRid)/native/%(Filename)%(Extension)" /> ]]></Text>
+            </ILCompilerBinPlace>
 
             <!-- IL.Compiler.SDK target files -->
             <ILCompilerSdkFiles Include="Runtime" />