Link against installed libc++/libc++abi when bootstrapping

The build tree layout does not necessarily match a valid libc++
installation tree, so install libc++/libc++abi first.

This is needed for llvm/llvm-project#115379

Reviewed By: vitalybuka

Pull Request: #299

zorg/buildbot/builders/sanitizers/buildbot_functions.sh

@@ -88,7 +88,7 @@ function rm_dirs {
 function cleanup() {
   [[ -v BUILDBOT_BUILDERNAME ]] || return 0
   echo @@@BUILD_STEP cleanup@@@
-  rm_dirs llvm_build2_* llvm_build_* libcxx_build_* compiler_rt_build* symbolizer_build* $@
+  rm_dirs llvm_build2_* llvm_build_* libcxx_build_* libcxx_install_* compiler_rt_build* symbolizer_build* "$@"
   if ccache -s >/dev/null ; then
     rm_dirs llvm_build64
   fi
@@ -228,6 +228,7 @@ function build_stage2 {
   echo @@@BUILD_STEP stage2/$sanitizer_name build libcxx@@@
 
   local libcxx_build_dir=libcxx_build_${sanitizer_name}
+  local libcxx_install_dir=libcxx_install_${sanitizer_name}
   local build_dir=llvm_build_${sanitizer_name}
   export STAGE2_DIR=${build_dir}
   local cmake_libcxx_cflags=
@@ -283,18 +284,22 @@ function build_stage2 {
   (cd ${libcxx_build_dir} && \
     cmake \
       ${cmake_stage2_common_options} \
+      -DCMAKE_INSTALL_PREFIX="${ROOT}/${libcxx_install_dir}" \
       -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi;libunwind' \
       -DLIBCXX_TEST_PARAMS='long_tests=False' \
       -DLIBCXXABI_USE_LLVM_UNWINDER=OFF \
       -DLLVM_USE_SANITIZER=${llvm_use_sanitizer} \
       -DCMAKE_C_FLAGS="${fsanitize_flag} ${cmake_libcxx_cflags} ${fno_sanitize_flag}" \
       -DCMAKE_CXX_FLAGS="${fsanitize_flag} ${cmake_libcxx_cflags} ${fno_sanitize_flag}" \
       $LLVM/../runtimes && \
-    ninja cxx cxxabi) || build_failure
+    ninja cxx cxxabi && ninja install-cxx install-cxxabi) || build_failure
+
+  local libcxx_so_path="$(find "${ROOT}/${libcxx_install_dir}" -name libc++.so)"
+  test -f "${libcxx_so_path}" || build_failure
+  local libcxx_runtime_path=$(dirname "${libcxx_so_path}")
 
-  local libcxx_runtime_path=$(dirname $(find ${ROOT}/${libcxx_build_dir} -name libc++.so))
   local sanitizer_ldflags="-Wl,--rpath=${libcxx_runtime_path} -L${libcxx_runtime_path}"
-  local sanitizer_cflags="-nostdinc++ -isystem ${ROOT}/${libcxx_build_dir}/include -isystem ${ROOT}/${libcxx_build_dir}/include/c++/v1 $fsanitize_flag"
+  local sanitizer_cflags="-nostdinc++ -isystem ${ROOT}/${libcxx_install_dir}/include -isystem ${ROOT}/${libcxx_install_dir}/include/c++/v1 $fsanitize_flag"
 
   echo @@@BUILD_STEP stage2/$sanitizer_name build@@@