[mono] Developer convenience MSBuild property

[imhameed]

Adds a property, named MonoCMakeExtraArgs, which is passed through to the CMake configure command invocation.

Example usage:

MonoCMakeExtraArgs="-DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_SHARED_LINKER_FLAGS=-fuse-ld=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_LINKER=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_AR=$HOME/clang-9.x/out/bin/llvm-ar -DCMAKE_RANLIB=$HOME/clang-9.x/out/bin/llvm-ranlib" \
./build.sh
    -configuration Release \
    --subset mono \
    /p:MonoLLVMUseCxx11Abi=true /p:MonoEnableLLVM=true \
    /p:MonoLLVMDir="$LLVM_PREFIX"

touch src/mono/mono/mini/mini-llvm.c && time ninja -C artifacts/obj/mono/Linux.x64.Release reports 5.3 seconds when using lld,
llvm-ar, and llvm-ranlib; this takes 18 seconds when using GNU tools.

Note that GCC doesn't support full paths for fuse-ld, unlike Clang.

[vargaz]

Wouldn't be better to add a single MonoCMakeExtraArgs msbuild property ?

[imhameed]

Cool:

./build.sh \
    -configuration Release \
    --subset mono \
    /p:MonoCMakeExtraArgs="-DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_SHARED_LINKER_FLAGS=-fuse-ld=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_LINKER=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_AR=$HOME/clang-9.x/out/bin/llvm-ar -DCMAKE_RANLIB=$HOME/clang-9.x/out/bin/llvm-ranlib" \
    /p:MonoLLVMUseCxx11Abi=true /p:MonoEnableLLVM=true \
    /p:MonoLLVMDir="$LLVM_PREFIX"

yields:

MSBUILD : error MSB1001: Unknown switch.
Switch: -DCMAKE_SHARED_LINKER_FLAGS=-fuse-ld=/home/imran/clang-9.x/out/bin/ld.lld

This works fine:

./dotnet.sh msbuild src/mono/mono.proj \
    /p:Configuration=Release \
    /p:MonoCMakeExtraArgs="-DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_SHARED_LINKER_FLAGS=-fuse-ld=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_LINKER=$HOME/clang-9.x/out/bin/ld.lld -DCMAKE_AR=$HOME/clang-9.x/out/bin/llvm-ar -DCMAKE_RANLIB=$HOME/clang-9.x/out/bin/llvm-ranlib" \
    /p:MonoLLVMUseCxx11Abi=true /p:MonoEnableLLVM=true \
    /p:MonoLLVMDir="$LLVM_PREFIX"

And also: dotnet/msbuild#2999