Framework source stepping not working for R2R assemblies in 6.0 Preview 3

[JiahongJin1]

Affected build:
VS Enterprise 2019: Version 16.10.0 preview 2.0 [31103.301.main]
NET 6 SDK: 6.0.100-preview.3.21181.22(runtime-6.0.0-preview.3.21181.6) from GitHub - https://github.com/dotnet/installer

Steps to reproduce
Testing on Windows with VS -

1. Goto Tools -> options -> Debugging
   Under General
   a. Uncheck 'Enable Just My Code'
   b. Check 'Suppress JIT optimization on module load (Managed only)'
   Under Symbols
   a. Check 'Microsoft Symbol Servers'

2. Create a new ASP.NET Razor project by doing
   mkdir razor
   cd razor
   dotnet new razor

3. Double click on the ‘Startup.cs’ file in the ‘Explorer’ pane to bring up that source code.

4. Add the following line to the Startup.cs file at the beginning of the ‘Configure’ method (at the bottom of the file). When using VS, you can add this line of code on Program.cs file
   Console.WriteLine("x " + 3);

5. Place a breakpoint on that line (F9).

6. Run the application until it hit that breakpoint (F5). It will load symbols from the Microsoft symbol server, and may take a few seconds to hit the breakpoint. You should see 20-30 lines of ‘Loaded XXX Symbols loaded’.

7. Step into the concatination method (F11). Select 'Download Source and Continue Debugging' from the popup
   This tests CoreCLR symbols AT THIS POINT IT SHOULD SHOW YOU THE SOURCE CODE FOR Concat().

8. Step out of Concat (Shift F11). Then step into the WriteLine method(F11). You may see the pop up as above, select the first option from it.
   This tests CoreFX symbols  AT THIS POINT IT SHOULD SHOW YOU THE SOURCE CODE FOR Console.WriteLine(). 

Expected Resut:
CoreCLR symbols are displayed in step7.
CoreFX symbols are displayed in step8.

Actual Result:
CoreCLR symbols are displayed in step7.
CoreFX symbols(Console.WriteLine()) are missing in step8.

Dotnet --info:
C:\Users\v-danche\source\repos\myrazor\razor>dotnet --info
.NET SDK (reflecting any global.json):
Version: 6.0.100-preview.3.21181.23
Commit: c86a01a271

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19042
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\6.0.100-preview.3.21181.23\

Host (useful for support):
Version: 6.0.0-preview.3.21181.6
Commit: a5f523c

.NET SDKs installed:
5.0.300-preview.21180.15 [C:\Program Files\dotnet\sdk]
6.0.100-preview.3.21181.23 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.0-preview.3.21181.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.0-preview.3.21181.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.0-preview.3.21181.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[marcpopMSFT]

@rbhanda Do you know how symbols get uploaded for our releases?

[rbhanda]

Hi @marcpopMSFT we upload symbols as part of the release process. I am looking into this right now.

[hoyosjs]

This doesn't feel like a symbol indexing issue. They both are uploaded in the same place. If you also turn off step over properties and operators, you can get to some of the library symbols and get the corresponding source. The implementation of that method goes to the getter of Console.Out and then System.IO.TextWriter.SyncTextWriter.WriteLine(string). If you manually step there using the disassembly you get to step to other places in the implementation. It looks like Out's getter is inlined and so is the WriteLine. If I disable ReadyToRun using COMPlus_ReadyToRun=0 then all the inlining stops and stepping in and source link work as expected. I am not sure if this is an issue within the PDB emitted by crossgen2, the implementation of stepping, or an issue with VS.

cc: @dotnet/dotnet-diag @trylek

Tagging subscribers to this area: @tommcdon
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Affected build:
VS Enterprise 2019: Version 16.10.0 preview 2.0 [31103.301.main]
NET 6 SDK: 6.0.100-preview.3.21181.22(runtime-6.0.0-preview.3.21181.6) from GitHub - https://github.com/dotnet/installer

Steps to reproduce
Testing on Windows with VS -

1. Goto Tools -> options -> Debugging
   Under General
   a. Uncheck 'Enable Just My Code'
   b. Check 'Suppress JIT optimization on module load (Managed only)'
   Under Symbols
   a. Check 'Microsoft Symbol Servers'

2. Create a new ASP.NET Razor project by doing
   mkdir razor
   cd razor
   dotnet new razor

3. Double click on the ‘Startup.cs’ file in the ‘Explorer’ pane to bring up that source code.

4. Add the following line to the Startup.cs file at the beginning of the ‘Configure’ method (at the bottom of the file). When using VS, you can add this line of code on Program.cs file
   Console.WriteLine("x " + 3);

5. Place a breakpoint on that line (F9).

6. Run the application until it hit that breakpoint (F5). It will load symbols from the Microsoft symbol server, and may take a few seconds to hit the breakpoint. You should see 20-30 lines of ‘Loaded XXX Symbols loaded’.

7. Step into the concatination method (F11). Select 'Download Source and Continue Debugging' from the popup
   This tests CoreCLR symbols AT THIS POINT IT SHOULD SHOW YOU THE SOURCE CODE FOR Concat().

8. Step out of Concat (Shift F11). Then step into the WriteLine method(F11). You may see the pop up as above, select the first option from it.
   This tests CoreFX symbols  AT THIS POINT IT SHOULD SHOW YOU THE SOURCE CODE FOR Console.WriteLine(). 

Expected Resut:
CoreCLR symbols are displayed in step7.
CoreFX symbols are displayed in step8.

Actual Result:
CoreCLR symbols are displayed in step7.
CoreFX symbols(Console.WriteLine()) are missing in step8.

Dotnet --info:
C:\Users\v-danche\source\repos\myrazor\razor>dotnet --info
.NET SDK (reflecting any global.json):
Version: 6.0.100-preview.3.21181.23
Commit: c86a01a271

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19042
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\6.0.100-preview.3.21181.23\

Host (useful for support):
Version: 6.0.0-preview.3.21181.6
Commit: a5f523c

.NET SDKs installed:
5.0.300-preview.21180.15 [C:\Program Files\dotnet\sdk]
6.0.100-preview.3.21181.23 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.0-preview.3.21181.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.0-preview.3.21181.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.0-preview.3.21181.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

Author:	JiahongJin1
Assignees:	rbhanda
Labels:	area-Diagnostics-coreclr, untriaged
Milestone:	-