Use arm jit for armel in crossgen2, and build the matching bits on all architectures

[davidwrighton]

Attempt to address use of crossgen2 on armel architectures. Fixes #49347

[davidwrighton]

@clamp03 I can't actually test this, as I don't know the docker image for doing an armel crossbuild. Can you provide a docker image that I can use here?

[davidwrighton]

The idea of the change is that the unix arm jit will be able to compile targetting soft_fp or normal hardware fp abi. And once we get rid of crossgen, we'll simply delete the armel jit we're currently building in favor of the configurable one.

[clamp03]

@davidwrighton Thank you for the update.

It fails to build armel with this patch in a restore stage.

/home/dheon/work/dotnet/jobs/net6/runtime/.dotnet/sdk/6.0.100-preview.2.21155.3/NuGet.RestoreEx.targets(19,5): error : An unexpected token "armel" was found at character position 26 in condition "'$(TargetArchitecture)=='armel'".  /home/d
heon/work/dotnet/jobs/net6/runtime/src/coreclr/tools/aot/crossgen2/crossgen2.csproj [/home/dheon/work/dotnet/jobs/net6/runtime/Build.proj

This is a Dockerfile that I put all instructions into. (without this patch).

FROM ubuntu:20.04

RUN apt-get update
RUN DEBIAN_FRONTEND="noninteractive" apt-get install -y build-essential git vim curl cmake make llvm-10 clang-10 lldb-10 liblldb-10-dev libunwind8 libunwind8-dev gettext libicu-dev liblttng-ust-dev libcurl4-openssl-dev libssl-dev libnuma-dev libkrb5-dev binutils-arm-linux-gnueabi zlib1g-dev libxml2-utils rpm2cpio cpio

WORKDIR /dotnet/
RUN git clone https://github.com/dotnet/runtime.git

WORKDIR /dotnet/runtime
RUN ROOTFS_DIR=/dotnet/rootfs/armel ./eng/common/cross/build-rootfs.sh armel tizen
RUN ROOTFS_DIR=/dotnet/rootfs/armel ./build.sh --portablebuild false --arch armel --os Linux --clang10 --restore --build --configuration Release --cross --subset clr+libs.native 
RUN ROOTFS_DIR=/dotnet/rootfs/armel ./build.sh --arch armel --os Linux --clang10 --restore --build --configuration Release --cross --subset libs.ref+libs.src+libs.pretest+libs.packages+libs.tests

Thank you.

[davidwrighton]

@clamp03, this looks to be working now although I see errors like the following "bash : error : setlocale: LC_ALL: cannot change locale (en_US.UTF-8) [/dotnet/runtime/src/libraries/Native/build-native.proj]" as it builds, but the failure to run crossgen2 seems to be fixed.

[davidwrighton]

Please let me know if the fix looks good in your scenario.

[davidwrighton]

@dotnet/crossgen-contrib

[clamp03]

@davidwrighton Thank you. And could you check two things?

• DEBUG BUILD FAIL: JIT_FLAG_SOFTFP_ABI is not defined.
  

  runtime/src/coreclr/jit/compiler.cpp

  Lines 3255 to 3257 in eceb5c8

  	#elif defined(ARM_SOFTFP)
  	// Armel is unconditionally enabled in the JIT. Verify that the VM side agrees.
  	assert(jitFlags->IsSet(JitFlags::JIT_FLAG_SOFTFP_ABI));

• CROSSGEN2 FAIL in HOST(x64): ARM_SOFTFP & CONFIGURABLE_ARM_ABI are not defined in clrjit_arm_x64
  

  runtime/src/coreclr/jit/CMakeLists.txt

  Lines 496 to 499 in eceb5c8

  	else()
  	if (CLR_CMAKE_TARGET_UNIX)
  	create_standalone_jit(TARGET clrjit_unix_${ARCH_TARGET_NAME}_${ARCH_HOST_NAME} OS unix ARCH ${ARCH_TARGET_NAME})
  	endif(CLR_CMAKE_TARGET_UNIX)

[davidwrighton]

Ok, the debug builds are running through.

[clamp03]

Isn't it better to use CLR_CMAKE_TARGET_ARCH_ARM?

if (CLR_CMAKE_TARGET_ARCH_ARM)

[clamp03]

It works well in my scenario.
Thank you so much.

[davidwrighton]

@trylek could you review this? While @clamp03 has reviewed it, I need a reviewer with write access to also approve it.

@dotnet/crossgen-contrib

[trylek]

LGTM