[wasm coreclr] workflow and near future work

[radekdoulik]

Workflow

Build the runtime like

./build.sh -bl -os browser -c Debug -subset clr.runtime+libs

That should install the emsdk, build the runtime and the libs.

To test the runtime startup I usually use these steps

• remove artifacts/obj/coreclr/browser.wasm.Debug/hosts/corewasmrun (this is because libs were not available at the time when corewasmrun was linked. this is temporary issue and will not happen once we have proper assembly loading)

• build simple-server like this

  ./dotnet.sh build -c Release src/mono/sample/wasm/simple-server

• build corewasmrun and run it in the browser. For quicker roundtrip, I run this command in src/coreclr

  (source "../mono/browser/emsdk/emsdk_env.sh" && cd ../../artifacts/obj/coreclr/browser.wasm.Debug/; make corewasmrun -j12) && (cp hosts/corewasmrun/index.html ../../artifacts/obj/coreclr/browser.wasm.Debug/hosts/corewasmrun/;cd ../../artifacts/obj/coreclr/browser.wasm.Debug/hosts/corewasmrun/; ~/git/runtime-main/src/mono/sample/wasm/simple-server/bin/Release/net8.0/HttpServer)

It builds the corewasmrun, opens index.html in the default browser and runs the runtime initialization. It should also forward the browser console output to the terminal. (if chrome is not your default browser, you can just copy the URL in chrome)

On windows it should work in similar way, you might need to run ninja instead of make though.

Debugging

For debugging I use chrome browser with "C/C++ DevTools Support (DWARF)" extension. It is not perfect, but works most of the time. It can step through C code, set breakpoints, inspect wasm linear memory.

Next steps

These are the areas to work on to progress with the runtime initialization and improve code in the main branch.

• helper calls opcodes - [wasm coreclr] helper call opcodes #119000

• pinvoke / Qcalls - [wasm coreclr] pinvoke / Qcalls #119001

• stackwalking - this is the current breaking point, need to find out how to handle it on wasm

• compare the wasm startup with desktop startup - it is possible we are already hitting managed exception somewhere

Current state

On main branch it gets to the point, where it compiles and runs 6 managed methods, before it breaks. The filtered (|grep Compiled) terminal output should look like this:

  log: stdout: Compiled method: .System.AppContext:Setup(ptr,ptr,int)
  log: stdout: Compiled method: .System.Diagnostics.Debug:Assert(bool,System.String)
  log: stdout: Compiled method: .System.Diagnostics.Debug:Assert(bool,System.String,System.String)
  log: stdout: Compiled method: .System.Collections.Generic.Dictionary`2[System.__Canon,System.__Canon]:.ctor(int)
  log: stdout: Compiled method: .System.Collections.Generic.Dictionary`2[System.__Canon,System.__Canon]:.ctor(int,System.Collections.Generic.IEqualityComparer`1[System.__Canon])
  log: stdout: Compiled method: .System.Object:.ctor()

With proof of concept code it compiles/runs 60 methods/native functions before it breaks. The code is in https://github.com/radekdoulik/runtime/tree/clr-interp-qcall-and-helper-call-poc branch. Filtered output looks like this:

  log: stdout: Compiled method: .System.AppContext:Setup(ptr,ptr,int)
  log: stdout: Compiled method: .System.Diagnostics.Debug:Assert(bool,System.String)
  log: stdout: Compiled method: .System.Diagnostics.Debug:Assert(bool,System.String,System.String)
  log: stdout: Compiled method: .System.Collections.Generic.Dictionary`2[System.__Canon,System.__Canon]:.ctor(int)
  log: stdout: Compiled method: .System.Collections.Generic.Dictionary`2[System.__Canon,System.__Canon]:.ctor(int,System.Collections.Generic.IEqualityComparer`1[System.__Canon])
  log: stdout: Compiled method: .System.Object:.ctor()
  log: stdout: Compiled method: .System.RuntimeTypeHandle:GetRuntimeTypeFromHandle(nint)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.TypeHandle:.ctor(ptr)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.TypeHandle:get_IsTypeDesc()
  log: stdout: Compiled method: .System.Runtime.CompilerServices.TypeHandle:AsMethodTable()
  log: stdout: Compiled method: .System.Runtime.CompilerServices.MethodTableAuxiliaryData:get_ExposedClassObject()
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:AsPointer[nint](byref)
  log: stdout: Compiled method: .System.RuntimeTypeHandle:GetRuntimeTypeFromHandleSlow(nint)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.ObjectHandleOnStack:Create[System.__Canon](byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:AsPointer[System.__Canon](byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.ObjectHandleOnStack:.ctor(ptr)
  log: stdout: InvokeCompiledMethod: System.RuntimeTypeHandle.GetRuntimeTypeFromHandleSlow --> RuntimeTypeHandle_GetRuntimeTypeFromHandleSlow [entrypoint]
  log: stdout: Compiled method: .System.Type:GetTypeFromHandle(System.RuntimeTypeHandle)
  log: stdout: Compiled method: .System.Type:get_IsValueType()
  log: stdout: Compiled method: .System.RuntimeType:IsValueTypeImpl()
  log: stdout: Compiled method: .System.RuntimeType:GetNativeTypeHandle()
  log: stdout: Compiled method: .System.Runtime.CompilerServices.MethodTable:get_IsValueType()
  log: stdout: Compiled method: .System.GC:KeepAlive(System.Object)
  log: stdout: Compiled method: .System.Collections.Generic.EqualityComparer`1[System.__Canon]:get_Default()
  log: stdout: Compiled method: .System.Runtime.CompilerServices.StaticsHelpers:GetGCStaticBase(ptr)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.MethodTableAuxiliaryData:GetDynamicStaticsInfo()
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:As[System.Runtime.CompilerServices.MethodTableAuxiliaryData,System.Runtime.CompilerServices.DynamicStaticsInfo](byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:Subtract[System.Runtime.CompilerServices.DynamicStaticsInfo](byref,int)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.StaticsHelpers:VolatileReadAsByref(byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:AsPointer[byte](byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.StaticsHelpers:GetGCStaticBaseSlow(ptr)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.InitHelpers:InitClassSlow(ptr)
  log: stdout: InvokeCompiledMethod: System.Runtime.CompilerServices.InitHelpers.InitClassHelper --> InitClassHelper [entrypoint]
  log: stdout: Compiled method: .System.Collections.Generic.EqualityComparer`1[System.__Canon]:.cctor()
  log: stdout: Compiled method: .System.Collections.Generic.ComparerHelpers:CreateDefaultEqualityComparer(System.Type)
  log: stdout: Compiled method: .System.Type:op_Inequality(System.Type,System.Type)
  log: stdout: Compiled method: .System.Type:op_Equality(System.Type,System.Type)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.CastHelpers:IsInstanceOfClass(ptr,System.Object)
  log: stdout: Compiled method: .System.Diagnostics.Debug:Fail(System.String,System.String)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.InitHelpers:InitClass(ptr)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.MethodTableAuxiliaryData:get_IsClassInited()
  log: stdout: Compiled method: .System.Threading.Volatile:Read(byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:AsRef[uint](byref)
  log: stdout: Compiled method: .System.Runtime.CompilerServices.Unsafe:As[uint,System.Threading.Volatile+VolatileUInt32](byref)
  log: stdout: InvokeCompiledMethod: System.Runtime.CompilerServices.InitHelpers.InitClassHelper --> InitClassHelper [entrypoint]
  log: stdout: Compiled method: .System.Diagnostics.Debug:.cctor()
  log: stdout: Compiled method: .System.Diagnostics.DebugProvider:.ctor()
  log: stdout: InvokeCompiledMethod: System.Runtime.CompilerServices.InitHelpers.InitClassHelper --> InitClassHelper [entrypoint]
  log: stdout: InvokeCompiledMethod: System.Runtime.CompilerServices.InitHelpers.InitClassHelper --> InitClassHelper [entrypoint]
  log: stdout: Compiled method: .System.Diagnostics.DebugProvider:Fail(System.String,System.String)
  log: stdout: Compiled method: .System.Diagnostics.StackTrace:.ctor(int,bool)
  log: stdout: Compiled method: .System.ArgumentOutOfRangeException:ThrowIfNegative[int](int,System.String)
  log: stdout: Compiled method: .System.Int32:IsNegative(int)
  log: stdout: Compiled method: .System.Diagnostics.StackTrace:InitializeForCurrentThread(int,bool)
  log: stdout: Compiled method: .System.Diagnostics.StackTrace:CaptureStackTrace(int,bool,System.Exception)
  log: stdout: Compiled method: .System.Diagnostics.StackFrameHelper:.ctor()
  log: stdout: Compiled method: .System.Diagnostics.StackFrameHelper:InitializeSourceInfo(bool,System.Exception)
  log: stdout: Compiled method: .System.Diagnostics.StackTrace:GetStackFramesInternal(System.Diagnostics.StackFrameHelper,bool,System.Exception)
  log: stdout: Compiled method: .System.Diagnostics.StackTrace:GetStackFramesInternal(System.Runtime.CompilerServices.ObjectHandleOnStack,bool,System.Runtime.CompilerServices.ObjectHandleOnStack)
  log: stdout: InvokeCompiledMethod: System.Diagnostics.StackTrace.<GetStackFramesInternal>g____PInvoke|0_0 --> StackTrace_GetStackFramesInternal [entrypoint]

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[AaronRobinsonMSFT]

Here are the instructions on Windows:

1. build.cmd -os browser -c Debug -subset clr.runtime+libs
2. dotnet.cmd build -c Release src\mono\sample\wasm\simple-server\
3. Remove artifacts\obj\coreclr\browser.wasm.Debug\hosts\corewasmrun directory
4. Rebuild corewasmrun
   a. cd artifacts\obj\coreclr\browser.wasm.Debug\
   b. Run src\mono\browser\emsdk\emsdk_env.cmd
   c. Build using ninja from VS install - ninja corewasmrun
5. Copy src\coreclr\hosts\corewasmrun\index.html to artifacts\obj\coreclr\browser.wasm.Debug\hosts\corewasmrun
6. Run src\mono\sample\wasm\simple-server\bin\Release\net8.0\HttpServer.exe in artifacts\obj\coreclr\browser.wasm.Debug\hosts\corewasmrun

[AaronRobinsonMSFT]

I've fixed up this workflow. See #119029.

[pavelsavara]

I've fixed up this workflow. See #119029.

With above PR you can just use dotnet-serve for browser debugging

.\build.cmd -os browser -c Debug -subset clr.runtime+libs
dotnet-serve --directory "artifacts\bin\coreclr\browser.wasm.Debug\corewasmrun"

To support DWARF debug symbols in your chrome dev tools install this extension
https://chromewebstore.google.com/detail/cc++-devtools-support-dwa/pdcpmagijalfljmkmjngeonclgbbannb?pli=1

[pavelsavara]

Running the same in console is as easy as

cd artifacts\bin\coreclr\browser.wasm.Debug\corewasmrun\
node corewasmrun.js

For debugging in VS code you can use NodeJS instead of browser

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "corewasmrun",
            "skipFiles": [
                "<node_internals>/**"
            ],
            "program": "corewasmrun.js",
            "cwd": "${workspaceFolder}\\artifacts\\bin\\coreclr\\browser.wasm.Debug\\corewasmrun\\"
        }
    ]
}

Set breakpoint into corewasmrun.js at line 1815
This is implementation of stdout/printf

And then you can stack walk into WASM code of interest