[libcxx] Require LLVM in libc++'s CMake.

[EricWF]

Summary

This patch change the libc++' standalone build so that it requires LLVM. Previously LLVM was only required to run the test suite.
libc++ now uses LLVM's CMake modules to handle shared options like LLVM_USE_SANITIZER and LLVM_ENABLE_32_BITS.

This patch fixes the following bugs:

• PR23670 - https://llvm.org/bugs/show_bug.cgi?id=23670
• PR23671 - https://llvm.org/bugs/show_bug.cgi?id=23671

[jroelofs]

test/lit.site.cfg.in

10

LLVM_BUILD_32_BITS is a property of the host
config.enable_32bit is a property of the target

we should keep these separate, and not conflate host & target.... they're not always the same!

www/index.html

187

s/where-you-want-to-live/where-you-want-source-to-live/

199

s/where-you-want-to-live/where-you-want-source-to-live/

[EricWF]

@jroelofs: Any input on how to better manage the host vs target distinction?

test/lit.site.cfg.in

10

I agree but I'm not sure the best way to handle this. compiler-rt and libcxxabi both already use LLVM_ENABLE_32BITS and they are libraries intended for the target. Do you have a suggestion about how to handle this?

[jroelofs]

test/lit.site.cfg.in

10

Maybe we ought to detect the case when target == host, and use LLVM_ENABLE_32BITS as the default in that case, otherwise force the user to specify it (they're cross compiling anyway, so it doesn't hurt them to specify more things).

To do that, I'd keep the name LIBCXX_BUILD_32_BITS, and put the detection stuff in some CMake goop. Then fix libcxxabi to match libcxx. Compiler_rt, too.

[EricWF]

Abandoning in favor of D11308.

CMakeLists.txt

  build directory and run 'cmake /path/to/${PROJECT_NAME} [options]' there."
  )
 
-if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  set(LIBCXX_LIBDIR_SUFFIX "" CACHE STRING
-      "Define suffix of library directory name (32/64)")
-
-  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
-  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
-
-  set(LIBCXX_BUILT_STANDALONE 1)
-else()
-  set(LIBCXX_LIBDIR_SUFFIX ${LLVM_LIBDIR_SUFFIX})
-endif()
+include(FindLLVM)
 
 #===============================================================================
 # Setup CMake Options

 option(LIBCXX_ENABLE_STDIN "Build libc++ with support for stdin/std::cin." ON)
 option(LIBCXX_ENABLE_STDOUT "Build libc++ with support for stdout/std::cout." ON)
 option(LIBCXX_ENABLE_THREADS "Build libc++ with support for threads." ON)
-option(LIBCXX_BUILD_32_BITS "Build 32 bit libc++" OFF)
 option(LIBCXX_ENABLE_MONOTONIC_CLOCK
   "Build libc++ with support for a monotonic clock.
    This option may only be used when LIBCXX_ENABLE_THREADS=OFF." ON)

 option(LIBCXX_ENABLE_STATIC_ABI_LIBRARY "Statically link the ABI library" OFF)
 set(LIBCXX_SYSROOT "" CACHE STRING "Use alternate sysroot.")
 set(LIBCXX_GCC_TOOLCHAIN "" CACHE STRING "Use alternate GCC toolchain.")
-if (LIBCXX_BUILT_STANDALONE)
-  set(LLVM_USE_SANITIZER "" CACHE STRING
-      "Define the sanitizer used to build the library and tests")
-endif()
 
 if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
   if (APPLE)

   list(APPEND LIBCXX_COMPILE_FLAGS -D_LIBCPP_BUILD_STATIC)
 endif()
 
-if (CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32)
-  if (LIBCXX_BUILD_32_BITS)
-    message(STATUS "Building 32 bits executables and libraries.")
-    list(APPEND LIBCXX_CXX_FLAGS "-m32")
-  endif()
-elseif(LIBCXX_BUILD_32_BITS)
-  message(FATAL_ERROR "LIBCXX_BUILD_32_BITS=ON is not supported on this platform.")
-endif()
 # This is the _ONLY_ place where add_definitions is called.
 if (MSVC)
   add_definitions(-D_CRT_SECURE_NO_WARNINGS)

                       " when LIBCXX_ENABLE_THREADS is also set to OFF.")
 endif()
 
-# Configure for sanitizers. If LIBCXX_BUILT_STANDALONE then we have to do
-# the flag translation ourselves. Othewise LLVM's CMakeList.txt will handle it.
-if (LIBCXX_BUILT_STANDALONE)
-  # NOTE: LLVM_USE_SANITIZER checks for a UNIX like system instead of MSVC.
-  # But we don't have LLVM_ON_UNIX so checking for MSVC is the best we can do.
-  if (LLVM_USE_SANITIZER AND NOT MSVC)
-    append_if(LIBCXX_CXX_FLAGS LIBCXX_HAS_FNO_OMIT_FRAME_POINTER_FLAG
-              "-fno-omit-frame-pointer")
-    if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" AND
-        NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "RELWITHDEBINFO")
-      append_if(LIBCXX_CXX_FLAGS LIBCXX_HAS_GLINE_TABLES_ONLY_FLAG
-                "-gline-tables-only")
-    endif()
-    if (LLVM_USE_SANITIZER STREQUAL "Address")
-      list(APPEND LIBCXX_CXX_FLAGS "-fsanitize=address")
-    elseif (LLVM_USE_SANITIZER MATCHES "Memory(WithOrigins)?")
-      list(APPEND LIBCXX_CXX_FLAGS "-fsanitize=memory")
-      if (LLVM_USE_SANITIZER STREQUAL "MemoryWithOrigins")
-        list(APPEND LIBCXX_CXX_FLAGS "-fsanitize-memory-track-origins")
-      endif()
-    elseif (LLVM_USE_SANITIZER STREQUAL "Undefined")
-      list(APPEND LIBCXX_CXX_FLAGS
-          "-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover")
-    elseif (LLVM_USE_SANITIZER STREQUAL "Thread")
-      list(APPEND LIBCXX_CXX_FLAGS "-fsanitize=thread")
-    else()
-      message(WARNING "Unsupported value of LLVM_USE_SANITIZER: ${LLVM_USE_SANITIZER}")
-    endif()
-  elseif(MSVC)
-    message(WARNING "LLVM_USE_SANITIZER is not supported with MSVC")
-  endif()
-endif()
-
 append_if(LIBCXX_CXX_FLAGS LIBCXX_TARGET_TRIPLE
           "-target ${LIBCXX_TARGET_TRIPLE}")
 

cmake/Modules/FindLLVM.cmake

+
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # Rely on llvm-config.
+  set(CONFIG_OUTPUT)
+  find_program(LLVM_CONFIG "llvm-config")
+  if(DEFINED LLVM_PATH)
+    set(LLVM_INCLUDE_DIR ${LLVM_INCLUDE_DIR} CACHE PATH "Path to llvm/include")
+    set(LLVM_PATH ${LLVM_PATH} CACHE PATH "Path to LLVM source tree")
+    set(LLVM_MAIN_SRC_DIR ${LLVM_PATH})
+    set(LLVM_CMAKE_PATH "${LLVM_PATH}/cmake/modules")
+  elseif(LLVM_CONFIG)
+    message(STATUS "Found LLVM_CONFIG as ${LLVM_CONFIG}")
+    set(CONFIG_COMMAND ${LLVM_CONFIG}
+      "--includedir"
+      "--prefix"
+      "--src-root")
+    execute_process(
+      COMMAND ${CONFIG_COMMAND}
+      RESULT_VARIABLE HAD_ERROR
+      OUTPUT_VARIABLE CONFIG_OUTPUT
+    )
+    if(NOT HAD_ERROR)
+      string(REGEX REPLACE
+        "[ \t]*[\r\n]+[ \t]*" ";"
+        CONFIG_OUTPUT ${CONFIG_OUTPUT})
+    else()
+      string(REPLACE ";" " " CONFIG_COMMAND_STR "${CONFIG_COMMAND}")
+      message(STATUS "${CONFIG_COMMAND_STR}")
+      message(FATAL_ERROR "llvm-config failed with status ${HAD_ERROR}")
+    endif()
+
+    list(GET CONFIG_OUTPUT 0 INCLUDE_DIR)
+    list(GET CONFIG_OUTPUT 1 LLVM_OBJ_ROOT)
+    list(GET CONFIG_OUTPUT 2 MAIN_SRC_DIR)
+
+    set(LLVM_INCLUDE_DIR ${INCLUDE_DIR} CACHE PATH "Path to llvm/include")
+    set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
+    set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
+    set(LLVM_CMAKE_PATH "${LLVM_BINARY_DIR}/share/llvm/cmake")
+  else()
+    message(FATAL_ERROR "llvm-config not found and LLVM_MAIN_SRC_DIR not defined. "
+                        "Reconfigure with -DLLVM_CONFIG=path/to/llvm-config "
+                        "or -DLLVM_PATH=path/to/llvm-source-root.")
+  endif()
+
+  if(EXISTS ${LLVM_CMAKE_PATH})
+    list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
+    include("${LLVM_CMAKE_PATH}/AddLLVM.cmake")
+    include("${LLVM_CMAKE_PATH}/HandleLLVMOptions.cmake")
+  else()
+    message(FATAL_ERROR "Not found: ${LLVM_CMAKE_PATH}")
+  endif()
+
+  if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+    set(LLVM_LIT ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+  else()
+    # Seek installed Lit.
+    find_program(LLVM_LIT "lit.py" ${LLVM_MAIN_SRC_DIR}/utils/lit
+      DOC "Path to lit.py")
+  endif()
+
+  if(LLVM_LIT)
+    # Define the default arguments to use with 'lit', and an option for the user
+    # to override.
+    set(LIT_ARGS_DEFAULT "-sv --show-xfail --show-unsupported")
+    if (MSVC OR XCODE)
+      set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
+    endif()
+    set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
+
+    # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
+    if( WIN32 AND NOT CYGWIN )
+      set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
+    endif()
+  else()
+    set(LLVM_INCLUDE_TESTS OFF)
+  endif()
+
+  set(LIBCXX_LIBDIR_SUFFIX "" CACHE STRING
+      "Define suffix of library directory name (32/64)")
+
+  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
+  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
+
+  set(LIBCXX_BUILT_STANDALONE 1)
+else()
+  set(LLVM_MAIN_SRC_DIR "${CMAKE_SOURCE_DIR}" CACHE PATH "Path to LLVM source tree")
+  set(LLVM_LIT "${CMAKE_SOURCE_DIR}/utils/lit/lit.py")
+  set(LIBCXX_LIBDIR_SUFFIX ${LLVM_LIBDIR_SUFFIX})
+endif()

test/CMakeLists.txt

   endif()
 endmacro()
 
-set(LIT_EXECUTABLE "" CACHE FILEPATH "Path to LLVM's llvm-lit.")
-
-if(LIBCXX_BUILT_STANDALONE)
-  # Make sure we can use the console pool for recent cmake and ninja > 1.5
-  if(CMAKE_VERSION VERSION_LESS 3.1.20141117)
-    set(cmake_3_2_USES_TERMINAL)
-  else()
-    set(cmake_3_2_USES_TERMINAL USES_TERMINAL)
-  endif()
-else()
-  include(FindPythonInterp)
-  if(PYTHONINTERP_FOUND)
-    set(LIT_EXECUTABLE
-        ${PYTHON_EXECUTABLE} ${CMAKE_SOURCE_DIR}/utils/lit/lit.py)
-  else()
-    message(WARNING "Could not find Python, cannot set LIT_EXECUTABLE.")
-  endif()
+set(LIBCXX_LIT_VARIANT "libcxx" CACHE STRING
+    "Configuration variant to use for LIT.")
+
+pythonize_bool(LIBCXX_ENABLE_EXCEPTIONS)
+pythonize_bool(LIBCXX_ENABLE_RTTI)
+pythonize_bool(LIBCXX_ENABLE_SHARED)
+pythonize_bool(LLVM_BUILD_32_BITS)
+pythonize_bool(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE)
+pythonize_bool(LIBCXX_ENABLE_STDIN)
+pythonize_bool(LIBCXX_ENABLE_STDOUT)
+pythonize_bool(LIBCXX_ENABLE_THREADS)
+pythonize_bool(LIBCXX_ENABLE_MONOTONIC_CLOCK)
+pythonize_bool(LIBCXX_GENERATE_COVERAGE)
+pythonize_bool(LIBCXXABI_USE_LLVM_UNWINDER)
+
+# The tests shouldn't link to any ABI library when it has been linked into
+# libc++ statically.
+if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
+  set(LIBCXX_CXX_ABI_LIBNAME "none")
 endif()
 
-if (LIT_EXECUTABLE)
-  set(LIT_ARGS_DEFAULT "-sv --show-unsupported --show-xfail")
-  if (MSVC OR XCODE)
-    set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
-  endif()
-  set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}"
-      CACHE STRING "Default options for lit")
-  set(LIT_ARGS "${LLVM_LIT_ARGS}")
-  separate_arguments(LIT_ARGS)
+set(LIBCXX_TARGET_INFO "libcxx.test.target_info.LocalTI" CACHE STRING
+    "TargetInfo to use when setting up test environment.")
+set(LIBCXX_EXECUTOR "None" CACHE STRING
+    "Executor to use when running tests.")
 
-  set(LIBCXX_LIT_VARIANT "libcxx" CACHE STRING
-      "Configuration variant to use for LIT.")
+set(AUTO_GEN_COMMENT "## Autogenerated by libcxx configuration.\n# Do not edit!")
 
-  pythonize_bool(LIBCXX_ENABLE_EXCEPTIONS)
-  pythonize_bool(LIBCXX_ENABLE_RTTI)
-  pythonize_bool(LIBCXX_ENABLE_SHARED)
-  pythonize_bool(LIBCXX_BUILD_32_BITS)
-  pythonize_bool(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE)
-  pythonize_bool(LIBCXX_ENABLE_STDIN)
-  pythonize_bool(LIBCXX_ENABLE_STDOUT)
-  pythonize_bool(LIBCXX_ENABLE_THREADS)
-  pythonize_bool(LIBCXX_ENABLE_MONOTONIC_CLOCK)
-  pythonize_bool(LIBCXX_GENERATE_COVERAGE)
-  pythonize_bool(LIBCXXABI_USE_LLVM_UNWINDER)
+configure_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+  ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
+  @ONLY)
 
-  # The tests shouldn't link to any ABI library when it has been linked into
-  # libc++ statically.
-  if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY)
-    set(LIBCXX_CXX_ABI_LIBNAME "none")
-  endif()
-  set(LIBCXX_TARGET_INFO "libcxx.test.target_info.LocalTI" CACHE STRING
-      "TargetInfo to use when setting up test environment.")
-  set(LIBCXX_EXECUTOR "None" CACHE STRING
-      "Executor to use when running tests.")
-
-  set(AUTO_GEN_COMMENT "## Autogenerated by libcxx configuration.\n# Do not edit!")
-
-  configure_file(
-    ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
-    ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
-    @ONLY)
+add_lit_testsuite(check-libcxx "Running libcxx tests"
+  ${CMAKE_CURRENT_BINARY_DIR}
+  DEPENDS cxx)
 
-  add_custom_target(check-libcxx
-    COMMAND ${LIT_EXECUTABLE}
-            ${LIT_ARGS}
-            ${CMAKE_CURRENT_BINARY_DIR}
-    DEPENDS cxx
-    COMMENT "Running libcxx tests"
-    ${cmake_3_2_USES_TERMINAL})
-
-  if (LIBCXX_GENERATE_COVERAGE)
-    include(CodeCoverage)
-    set(output_dir "${CMAKE_CURRENT_BINARY_DIR}/coverage")
-    set(capture_dirs "${LIBCXX_LIB_CMAKEFILES_DIR}/cxx.dir/;${CMAKE_CURRENT_BINARY_DIR}")
-    set(extract_dirs "${LIBCXX_SOURCE_DIR}/include;${LIBCXX_SOURCE_DIR}/src")
-    setup_lcov_test_target_coverage("cxx" "${output_dir}" "${capture_dirs}" "${extract_dirs}")
-  endif()
-else()
-  message(WARNING
-          "LIT_EXECUTABLE not set, no check-libcxx target will be available!")
+if (LIBCXX_GENERATE_COVERAGE)
+  include(CodeCoverage)
+  set(output_dir "${CMAKE_CURRENT_BINARY_DIR}/coverage")
+  set(capture_dirs "${LIBCXX_LIB_CMAKEFILES_DIR}/cxx.dir/;${CMAKE_CURRENT_BINARY_DIR}")
+  set(extract_dirs "${LIBCXX_SOURCE_DIR}/include;${LIBCXX_SOURCE_DIR}/src")
+  setup_lcov_test_target_coverage("cxx" "${output_dir}" "${capture_dirs}" "${extract_dirs}")
 endif()

test/lit.site.cfg.in

 config.enable_exceptions        = "@LIBCXX_ENABLE_EXCEPTIONS@"
 config.enable_rtti              = "@LIBCXX_ENABLE_RTTI@"
 config.enable_shared            = "@LIBCXX_ENABLE_SHARED@"
-config.enable_32bit             = "@LIBCXX_BUILD_32_BITS@"
+config.enable_32bit             = "@LLVM_BUILD_32_BITS@"
 config.enable_global_filesystem_namespace = "@LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE@"
 config.enable_stdin             = "@LIBCXX_ENABLE_STDIN@"
 config.enable_stdout            = "@LIBCXX_ENABLE_STDOUT@"

www/index.html

 
   <p>In-tree build:</p>
   <ul>
+    <li><code>cd where-you-want-to-live</code></li>
     <li>Check out libcxx and <a href="http://libcxxabi.llvm.org/">libcxxabi</a>
       into llvm/projects</li>
-    <li><code>cd llvm</code></li>
+    <li><code>cd where-you-want-to-build</code></li>
     <li><code>mkdir build &amp;&amp; cd build</code></li>
-    <li><code>cmake .. # Linux may require -DCMAKE_C_COMPILER=clang
+    <li><code>cmake path/to/llvm # Linux may require -DCMAKE_C_COMPILER=clang
         -DCMAKE_CXX_COMPILER=clang++</code></li>
     <li><code>make cxx</code></li>
   </ul>
 
   <p>Out-of-tree build:</p>
   <ul>
-    <li>Check out libcxx</li>
+    <li><code>cd where-you-want-to-live</code></li>
+    <li>Check out libcxx and llvm</li>
     <li>If not on a Mac, also check out
       <a href="http://libcxxabi.llvm.org/">libcxxabi</a></li>
-    <li><code>cd libcxx</code></li>
+    <li><code>cd where-you-want-to-build</code></li>
     <li><code>mkdir build &amp;&amp; cd build</code></li>
-    <li><code>cmake -DLIBCXX_CXX_ABI=libcxxabi
+    <li><code>cmake -DLLVM_PATH=path/to/llvm
+        -DLIBCXX_CXX_ABI=libcxxabi
         -DLIBCXX_CXX_ABI_INCLUDE_PATHS=path/to/libcxxabi/include
-        -DLIT_EXECUTABLE=path/to/llvm/utils/lit/lit.py .. # Linux may require
-        -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++</code></li>
+        -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
+        path/to/libcxx
+    </code></li>
     <li><code>make</code></li>
   </ul>