C4242 error when compiling CoreCLR on Windows with -msbuild

AustinWise commented 7 months ago

Description

Compiling with the -msbuild flag fails with many C4242 errors in libunwind.

Reproduction Steps

On commit 4e0d5d4bb45ecd9a74f651a0682b8d5371c9695b

build.cmd -s clr -c debug -msbuild

Expected behavior

Compiles successfully. Note that that compiling with Ninja works fine:

build.cmd -s clr -c debug -ninja

Actual behavior

Many errors like this:

src\native\external\libunwind\include\libunwind_i.h(342,13): error C4242: '=': conversion from 'ssize_t' to 'int', possible loss of data [artifacts\obj\external\libunwind\libunwind_xdac.vcxproj] (compiling source file 'src/native/external/libunwind/src/os-linux.c')

Regression?

Presumably this has something to do with #99470.

Known Workarounds

No response

Configuration

Visual Studio 2022 v17.9.4
cmake version 3.28.0
Windows 11 10.0.22631.3296
Windows SDK version 10.0.22621.0

Other information

It looks like the intention was to not enable this warning for libunwind:

https://github.com/dotnet/runtime/blob/6c685e3302ebdc2aeb008a40ff475d3d3b9f2a78/src/native/external/libunwind_extras/CMakeLists.txt#L143

One thing I notice is that eng\native\configurecompiler.cmake turns this warning on guarded by if (MSVC) while src/native/external/libunwind_extras/CMakeLists.txt tries to turn this off guarded by if(CLR_CMAKE_HOST_WIN32). I'm not enough of an expert on CMake to know if this is a problem or not.

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filipnavara commented 7 months ago

I can reproduce. I have a branch that fixes enough of the C4242 warnings to pass through this. Generally the work is tracked in #99471.

dotnet / runtime