Running ASan tests on AArch64

Hi,

I would like to run ASan tests on AArch64, to make sure I don't break
them while doing some cleanup.

Since it seems that
http://clang.llvm.org/get_started.html
is outdated, here is how I built my clang toolchain:
- checkout LLVM, Clang and compiler-rt
- add clang and compiler-rt symlinks into llvm/tools and llvm/projects
- call cmake:
  cmake ../llvm_tmp_src -DCMAKE_BUILD_TYPE=Release ../llvm_tmp_src/
- build:
- make -j4

This seemed to work, after I patched compiler-rt/cmake/config-ix.cmake
and replaced -march=aarch64 with -march=armv8-a.

At this point, make check-asan does not work:
make: *** No rule to make target `check-asan'. Stop.

So I tried the last part of the instructions found here:

mkdir compiler-rt_obj && cd compiler-rt_obj
cmake -DCMAKE_C_COMPILER=/your/c/compiler \
        -DCMAKE_CXX_COMPILER=/your/cxx/compiler \
        -DLLVM_CONFIG_PATH=../llvm_tmp_obj/bin/llvm-config \
        ../compiler-rt_src

Using the compiler previously built above as /your/c/compiler.

This step succeeds too, or seems to.

But still, make check-asan:
make: *** No rule to make target `check-asan'. Stop.

I must be missing something.

What is the recommended way of running asan tests?

Thanks

Christophe.