[libc++] Run the Lit test suite against an installed version of the library (#96910)

We always strive to test libc++ as close as possible to the way we are
actually shipping it. This was approximated reasonably well by setting
up the minimal driver flags when running the test suite, however we were
running the test suite against the library located in the build
directory.

This patch improves the situation by installing the library (the
headers, the built library, modules, etc) into a fake location and then
running the test suite against that fake "installation root".

This should open the door to getting rid of the temporary copy of the
headers we make during the build process, however this is left for a
future improvement.

Note that this adds quite a bit of verbosity whenever running the test
suite because we install the headers beforehand every time. We should be
able to override this to silence it, however CMake doesn't currently
give us a way to do that, see https://gitlab.kitware.com/cmake/cmake/-/issues/26085.

Author: ldionne

libcxx/CMakeLists.txt

@@ -131,7 +131,11 @@ option(LIBCXX_ENABLE_VENDOR_AVAILABILITY_ANNOTATIONS
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-shared-gcc.cfg.in")
 elseif(MINGW)
-  set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-mingw.cfg.in")
+  if (LIBCXX_ENABLE_SHARED)
+    set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-shared-mingw.cfg.in")
+  else()
+    set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-static-mingw.cfg.in")
+  endif()
 elseif(WIN32) # clang-cl
   if (LIBCXX_ENABLE_SHARED)
     set(LIBCXX_DEFAULT_TEST_CONFIG "llvm-libc++-shared-clangcl.cfg.in")

libcxx/cmake/caches/Apple.cmake

@@ -1,4 +1,5 @@
 set(CMAKE_BUILD_TYPE MinSizeRel CACHE STRING "")
+set(CMAKE_INSTALL_NAME_DIR "/usr/lib" CACHE STRING "")
 set(CMAKE_POSITION_INDEPENDENT_CODE OFF CACHE BOOL "")
 
 set(LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")

libcxx/modules/CMakeLists.txt

@@ -202,7 +202,6 @@ add_custom_target(generate-cxx-modules
   ALL DEPENDS
     ${_all_modules}
 )
-add_dependencies(cxx-test-depends generate-cxx-modules)
 
 # Configure the modules manifest.
 # Use the relative path between the installation and the module in the json

libcxx/src/CMakeLists.txt

@@ -309,7 +309,6 @@ endif()
 
 # Add a meta-target for both libraries.
 add_custom_target(cxx DEPENDS ${LIBCXX_BUILD_TARGETS})
-add_dependencies(cxx-test-depends cxx)
 
 set(LIBCXX_EXPERIMENTAL_SOURCES
   experimental/keep.cpp
@@ -357,7 +356,6 @@ set_target_properties(cxx_experimental
 )
 cxx_add_common_build_flags(cxx_experimental)
 target_compile_options(cxx_experimental PUBLIC -D_LIBCPP_ENABLE_EXPERIMENTAL)
-add_dependencies(cxx-test-depends cxx_experimental)
 
 if (LIBCXX_INSTALL_SHARED_LIBRARY)
   install(TARGETS cxx_shared

libcxx/test/CMakeLists.txt

@@ -5,6 +5,62 @@ if (LIBCXX_INCLUDE_BENCHMARKS)
   add_subdirectory(benchmarks)
 endif()
 
+# Install the library at a fake location so we can run the test suite against it.
+# This ensures that we run the test suite against a setup that matches what we ship
+# in production as closely as possible (in terms of file paths, rpaths, etc).
+set(LIBCXX_TESTING_INSTALL_PREFIX "${LIBCXX_BINARY_DIR}/test-suite-install")
+if (LIBCXX_CXX_ABI STREQUAL "libcxxabi")
+  add_custom_target(install-cxxabi-test-suite-prefix
+                        DEPENDS cxxabi-headers
+                                cxxabi
+                        COMMAND ${CMAKE_COMMAND} -E make_directory "${LIBCXX_TESTING_INSTALL_PREFIX}"
+                        COMMAND "${CMAKE_COMMAND}"
+                                -DCMAKE_INSTALL_COMPONENT=cxxabi-headers
+                                -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+                                -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
+                        COMMAND "${CMAKE_COMMAND}"
+                                -DCMAKE_INSTALL_COMPONENT=cxxabi
+                                -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+                                -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
+  add_dependencies(cxx-test-depends install-cxxabi-test-suite-prefix)
+endif()
+
+if (LIBCXXABI_USE_LLVM_UNWINDER AND TARGET unwind)
+  add_custom_target(install-unwind-test-suite-prefix
+  DEPENDS unwind-headers
+          unwind
+  COMMAND ${CMAKE_COMMAND} -E make_directory "${LIBCXX_TESTING_INSTALL_PREFIX}"
+  COMMAND "${CMAKE_COMMAND}"
+          -DCMAKE_INSTALL_COMPONENT=unwind-headers
+          -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+          -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
+  COMMAND "${CMAKE_COMMAND}"
+          -DCMAKE_INSTALL_COMPONENT=unwind
+          -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+          -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
+  add_dependencies(cxx-test-depends install-unwind-test-suite-prefix)
+endif()
+
+add_custom_target(install-cxx-test-suite-prefix
+                      DEPENDS cxx-headers
+                              cxx
+                              cxx_experimental
+                              cxx-modules
+                      COMMAND ${CMAKE_COMMAND} -E make_directory "${LIBCXX_TESTING_INSTALL_PREFIX}"
+                      COMMAND "${CMAKE_COMMAND}"
+                              -DCMAKE_INSTALL_COMPONENT=cxx-headers
+                              -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+                              -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
+                      COMMAND "${CMAKE_COMMAND}"
+                              -DCMAKE_INSTALL_COMPONENT=cxx-modules
+                              -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+                              -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
+                      COMMAND "${CMAKE_COMMAND}"
+                              -DCMAKE_INSTALL_COMPONENT=cxx
+                              -DCMAKE_INSTALL_PREFIX="${LIBCXX_TESTING_INSTALL_PREFIX}"
+                              -P "${LIBCXX_BINARY_DIR}/cmake_install.cmake")
+add_dependencies(cxx-test-depends install-cxx-test-suite-prefix)
+
 set(AUTO_GEN_COMMENT "## Autogenerated by libcxx configuration.\n# Do not edit!")
 set(SERIALIZED_LIT_PARAMS "# Lit parameters serialized here for llvm-lit to pick them up\n")
 

libcxx/test/configs/cmake-bridge.cfg.in

@@ -24,8 +24,9 @@ config.test_exec_root = os.path.join('@CMAKE_BINARY_DIR@', 'test')
 
 # Add substitutions for bootstrapping the test suite configuration
 config.substitutions.append(('%{libcxx-dir}', '@LIBCXX_SOURCE_DIR@'))
-config.substitutions.append(('%{include-dir}', '@LIBCXX_GENERATED_INCLUDE_DIR@'))
-config.substitutions.append(('%{target-include-dir}', '@LIBCXX_GENERATED_INCLUDE_TARGET_DIR@'))
-config.substitutions.append(('%{lib-dir}', '@LIBCXX_LIBRARY_DIR@'))
-config.substitutions.append(('%{module-dir}', '@LIBCXX_GENERATED_MODULE_DIR@'))
+config.substitutions.append(('%{install-prefix}', '@LIBCXX_TESTING_INSTALL_PREFIX@'))
+config.substitutions.append(('%{include-dir}', '@LIBCXX_TESTING_INSTALL_PREFIX@/@LIBCXX_INSTALL_INCLUDE_DIR@'))
+config.substitutions.append(('%{target-include-dir}', '@LIBCXX_TESTING_INSTALL_PREFIX@/@LIBCXX_INSTALL_INCLUDE_TARGET_DIR@'))
+config.substitutions.append(('%{lib-dir}', '@LIBCXX_TESTING_INSTALL_PREFIX@/@LIBCXX_INSTALL_LIBRARY_DIR@'))
+config.substitutions.append(('%{module-dir}', '@LIBCXX_TESTING_INSTALL_PREFIX@/@LIBCXX_INSTALL_MODULES_DIR@'))
 config.substitutions.append(('%{test-tools-dir}', '@LIBCXX_TEST_TOOLS_PATH@'))

libcxx/test/configs/llvm-libc++-shared-clangcl.cfg.in

@@ -25,7 +25,7 @@ config.substitutions.append(('%{link_flags}',
     '-nostdlib -L %{lib-dir} -lc++ -l' + cxx_lib
 ))
 config.substitutions.append(('%{exec}',
-    '%{executor} --execdir %T --prepend_env PATH=%{lib-dir} -- '
+    '%{executor} --execdir %T --prepend_env PATH=%{install-prefix}/bin -- '
 ))
 
 import os, site

libcxx/test/configs/llvm-libc++-shared-mingw.cfg.in

@@ -0,0 +1,25 @@
+# This testing configuration handles running the test suite against LLVM's libc++
+# using either a DLL or a static library, with MinGW/Clang on Windows.
+
+lit_config.load_config(config, '@CMAKE_CURRENT_BINARY_DIR@/cmake-bridge.cfg')
+
+config.substitutions.append(('%{flags}', ''))
+config.substitutions.append(('%{compile_flags}',
+    '-nostdinc++ -I %{target-include-dir} -I %{include-dir} -I %{libcxx-dir}/test/support'
+))
+config.substitutions.append(('%{link_flags}',
+    '-nostdlib++ -L %{lib-dir} -lc++'
+))
+config.substitutions.append(('%{exec}',
+    '%{executor} --execdir %T --prepend_env PATH=%{install-prefix}/bin -- '
+))
+
+import os, site
+site.addsitedir(os.path.join('@LIBCXX_SOURCE_DIR@', 'utils'))
+import libcxx.test.params, libcxx.test.config
+libcxx.test.config.configure(
+    libcxx.test.params.DEFAULT_PARAMETERS,
+    libcxx.test.features.DEFAULT_FEATURES,
+    config,
+    lit_config
+)

libcxx/test/configs/llvm-libc++-shared-no-vcruntime-clangcl.cfg.in

@@ -26,7 +26,7 @@ config.substitutions.append(('%{link_flags}',
     '-nostdlib -L %{lib-dir} -lc++ -l' + cxx_lib
 ))
 config.substitutions.append(('%{exec}',
-    '%{executor} --execdir %T --prepend_env PATH=%{lib-dir} -- '
+    '%{executor} --execdir %T --prepend_env PATH=%{install-prefix}/bin -- '
 ))
 
 import os, site

libcxx/test/configs/llvm-libc++-mingw.cfg.in renamed to libcxx/test/configs/llvm-libc++-static-mingw.cfg.in

@@ -32,10 +32,8 @@
 // various tools like dyld and ld64 will treat us specially if they recognize us as being a
 // system library.
 //
-// TODO: We currently don't do that correctly in the CMake build.
-//
-// XRUNX: otool -L "%{lib-dir}/libc++.1.dylib" | grep '/usr/lib/libc++.1.dylib'
-// XRUNX: ! otool -l "%{lib-dir}/libc++.1.dylib" | grep -E "LC_RPATH|@loader_path|@rpath"
+// RUN: otool -L "%{lib-dir}/libc++.1.dylib" | grep '/usr/lib/libc++.1.dylib'
+// RUN: otool -l "%{lib-dir}/libc++.1.dylib" | grep -vE "LC_RPATH|@loader_path|@rpath"
 
 // Make sure the compatibility_version of libc++ is 1.0.0.
 // Failure to respect this can result in applications not being able to find libc++

libcxx/test/libcxx/vendor/apple/system-install-properties.sh.cpp

@@ -129,7 +129,6 @@ for arch in ${architectures}; do
                 -C "${llvm_root}/libcxx/cmake/caches/Apple.cmake" \
                 -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" \
                 -DCMAKE_INSTALL_PREFIX="${build_dir}/${arch}-install" \
-                -DCMAKE_INSTALL_NAME_DIR="/usr/lib" \
                 -DCMAKE_OSX_ARCHITECTURES="${arch}" \
                 -DLIBCXXABI_LIBRARY_VERSION="${version}" \
                 -DLIBCXX_LIBRARY_VERSION="${version}" \

libcxx/utils/ci/apple-install-libcxx.sh

@@ -154,19 +154,6 @@ function check-runtimes() {
 
     echo "+++ Running the libunwind tests"
     ${NINJA} -vC "${BUILD_DIR}" check-unwind
-
-    # TODO: On macOS 13.5, the linker seems to have an issue where it will pick up
-    #       a library if it exists inside a -L search path, even if we don't link
-    #       against that library. This happens with libunwind.dylib if it is built
-    #       at the point when we run the libc++ tests, which causes issues cause we
-    #       are also linking against the system unwinder.
-    #
-    #       I believe this is a linker regression and I reported it as rdar://115842730.
-    #       It should be possible to move this installation step back to the top once
-    #       that issue has been resolved, but in the meantime it doesn't really hurt to
-    #       have it here.
-    echo "--- Installing libc++, libc++abi and libunwind to a fake location"
-    ${NINJA} -vC "${BUILD_DIR}" install-cxx install-cxxabi install-unwind
 }
 
 # TODO: The goal is to test this against all configurations. We should also move