Merge topic 'clang-libstdcpp-support'

5750fcd7b4 ci: enable `import_std23` module compilation with clang 52e2785018 experimental/CXXModules: recycle the UUID 28333c4516 Clang/CXXImportStd: support `-stdlib=libstdc++` Acked-by: Kitware Robot <kwrobot@kitware.com> Merge-request: !10727
2025-10-14 02:08:27 +08:00 · 2025-05-01 12:40:35 +00:00
parent f27eee63dd 5750fcd7b4
commit 74e677f62b
13 changed files with 43 additions and 30 deletions
--- a/.gitlab/ci/configure_fedora42_ninja_clang.cmake
+++ b/.gitlab/ci/configure_fedora42_ninja_clang.cmake
@@ -1,3 +1,3 @@
-set(CMake_TEST_MODULE_COMPILATION "named,compile_commands,collation,partitions,internal_partitions,export_bmi,install_bmi,shared,bmionly,build_database" CACHE STRING "")
+set(CMake_TEST_MODULE_COMPILATION "named,compile_commands,collation,partitions,internal_partitions,export_bmi,install_bmi,shared,bmionly,build_database,import_std23" CACHE STRING "")

 include("${CMAKE_CURRENT_LIST_DIR}/configure_fedora42_common_clang.cmake")
--- a/Help/dev/experimental.rst
+++ b/Help/dev/experimental.rst
@@ -81,7 +81,7 @@ In order to activate support for ``import std`` in C++23 and newer targets,
 set

 * variable ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` to
-* value ``a9e1cf81-9932-4810-974b-6eccaf14e457``.
+* value ``d0edc3af-4c50-42ea-a356-e2862fe7a444``.

 This UUID may change in future versions of CMake.  Be sure to use the value
 documented here by the source tree of the version of CMake with which you are
--- a/Help/manual/cmake-cxxmodules.7.rst
+++ b/Help/manual/cmake-cxxmodules.7.rst
@@ -92,7 +92,7 @@ Compilers which CMake natively supports module dependency scanning include:
 Support for ``import std`` is limited to the following toolchain and standard
 library combinations:

-* Clang 18.1.2 and newer with ``-stdlib=libc++``
+* Clang 18.1.2 and newer with ``-stdlib=libc++`` or ``-stdlib=libstdc++``
 * MSVC toolset 14.36 and newer (provided with Visual Studio 17.6 Preview 2 and
  newer)
 * GCC 15 and newer.
--- a/Modules/Compiler/Clang-CXX-CXXImportStd.cmake
+++ b/Modules/Compiler/Clang-CXX-CXXImportStd.cmake
@@ -1,7 +1,11 @@
 function (_cmake_cxx_import_std std variable)
-  if (NOT CMAKE_CXX_STANDARD_LIBRARY STREQUAL "libc++")
+  if (CMAKE_CXX_STANDARD_LIBRARY STREQUAL "libc++")
+    set(_clang_modules_json_impl "libc++")
+  elseif (CMAKE_CXX_STANDARD_LIBRARY STREQUAL "libstdc++")
+    set(_clang_modules_json_impl "libstdc++")
+  else ()
    set("${variable}"
-      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"Only `libc++` is supported\")\n"
+      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"Only `libc++` and `libstdc++` are supported\")\n"
      PARENT_SCOPE)
    return ()
  endif ()
@@ -10,7 +14,7 @@ function (_cmake_cxx_import_std std variable)
    COMMAND
      "${CMAKE_CXX_COMPILER}"
      ${CMAKE_CXX_COMPILER_ID_ARG1}
-      -print-file-name=libc++.modules.json
+      "-print-file-name=${_clang_modules_json_impl}.modules.json"
    OUTPUT_VARIABLE _clang_libcxx_modules_json_file
    ERROR_VARIABLE _clang_libcxx_modules_json_file_err
    RESULT_VARIABLE _clang_libcxx_modules_json_file_res
@@ -18,7 +22,7 @@ function (_cmake_cxx_import_std std variable)
    ERROR_STRIP_TRAILING_WHITESPACE)
  if (_clang_libcxx_modules_json_file_res)
    set("${variable}"
-      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"Could not find `libc++.modules.json` resource\")\n"
+      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"Could not find `${_clang_modules_json_impl}.modules.json` resource\")\n"
      PARENT_SCOPE)
    return ()
  endif ()
@@ -26,17 +30,18 @@ function (_cmake_cxx_import_std std variable)
  # Without this file, we do not have modules installed.
  if (NOT EXISTS "${_clang_libcxx_modules_json_file}")
    set("${variable}"
-      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"`libc++.modules.json` resource does not exist\")\n"
+      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"`${_clang_modules_json_impl}.modules.json` resource does not exist\")\n"
      PARENT_SCOPE)
    return ()
  endif ()

-  if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "18.1.2")
+  if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "18.1.2" AND
+      CMAKE_CXX_STANDARD_LIBRARY STREQUAL "libc++")
    # The original PR had a key spelling mismatch internally. Do not support it
    # and instead require a release known to have the fix.
    # https://github.com/llvm/llvm-project/pull/83036
    set("${variable}"
-      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"LLVM 18.1.2 is required for `libc++.modules.json` format fix\")\n"
+      "set(CMAKE_CXX${std}_COMPILER_IMPORT_STD_NOT_FOUND_MESSAGE \"LLVM 18.1.2 is required for `${_clang_modules_json_impl}.modules.json` format fix\")\n"
      PARENT_SCOPE)
    return ()
  endif ()
@@ -91,9 +96,15 @@ function (_cmake_cxx_import_std std variable)

    string(JSON _clang_modules_json_module_source GET "${_clang_modules_json_module}" "source-path")
    string(JSON _clang_modules_json_module_is_stdlib GET "${_clang_modules_json_module}" "is-std-library")
-    string(JSON _clang_modules_json_module_local_arguments GET "${_clang_modules_json_module}" "local-arguments")
-    string(JSON _clang_modules_json_module_nsystem_include_directories LENGTH "${_clang_modules_json_module_local_arguments}" "system-include-directories")
+    string(JSON _clang_modules_json_module_local_arguments ERROR_VARIABLE _clang_modules_json_module_local_arguments_error GET "${_clang_modules_json_module}" "local-arguments")
+    string(JSON _clang_modules_json_module_nsystem_include_directories ERROR_VARIABLE _clang_modules_json_module_nsystem_include_directories_error LENGTH "${_clang_modules_json_module_local_arguments}" "system-include-directories")

+    if (_clang_modules_json_module_local_arguments_error)
+      set(_clang_modules_json_module_local_arguments "")
+    endif ()
+    if (_clang_modules_json_module_nsystem_include_directories_error)
+      set(_clang_modules_json_module_nsystem_include_directories 0)
+    endif ()
    if (NOT IS_ABSOLUTE "${_clang_modules_json_module_source}")
      string(PREPEND _clang_modules_json_module_source "${_clang_modules_dir}/")
    endif ()
@@ -104,16 +115,18 @@ function (_cmake_cxx_import_std std variable)
      set(_clang_modules_is_stdlib 1)
    endif ()

-    math(EXPR _clang_modules_json_module_nsystem_include_directories_range "${_clang_modules_json_module_nsystem_include_directories} - 1")
-    foreach (_clang_modules_json_modules_system_include_directories_idx RANGE 0 "${_clang_modules_json_module_nsystem_include_directories_range}")
-      string(JSON _clang_modules_json_module_system_include_directory GET "${_clang_modules_json_module_local_arguments}" "system-include-directories" "${_clang_modules_json_modules_system_include_directories_idx}")
+    if (_clang_modules_json_module_nsystem_include_directories)
+      math(EXPR _clang_modules_json_module_nsystem_include_directories_range "${_clang_modules_json_module_nsystem_include_directories} - 1")
+      foreach (_clang_modules_json_modules_system_include_directories_idx RANGE 0 "${_clang_modules_json_module_nsystem_include_directories_range}")
+        string(JSON _clang_modules_json_module_system_include_directory GET "${_clang_modules_json_module_local_arguments}" "system-include-directories" "${_clang_modules_json_modules_system_include_directories_idx}")

-      if (NOT IS_ABSOLUTE "${_clang_modules_json_module_system_include_directory}")
-        string(PREPEND _clang_modules_json_module_system_include_directory "${_clang_modules_dir}/")
-      endif ()
-      list(APPEND _clang_modules_include_dirs_list
-        "${_clang_modules_json_module_system_include_directory}")
-    endforeach ()
+        if (NOT IS_ABSOLUTE "${_clang_modules_json_module_system_include_directory}")
+          string(PREPEND _clang_modules_json_module_system_include_directory "${_clang_modules_dir}/")
+        endif ()
+        list(APPEND _clang_modules_include_dirs_list
+          "${_clang_modules_json_module_system_include_directory}")
+      endforeach ()
+    endif ()
  endforeach ()

  # Split the paths into basedirs and module paths.
--- a/Source/cmExperimental.cxx
+++ b/Source/cmExperimental.cxx
@@ -39,7 +39,7 @@ cmExperimental::FeatureData LookupTable[] = {
    false },
  // CxxImportStd
  { "CxxImportStd",
-    "a9e1cf81-9932-4810-974b-6eccaf14e457",
+    "d0edc3af-4c50-42ea-a356-e2862fe7a444",
    "CMAKE_EXPERIMENTAL_CXX_IMPORT_STD",
    "CMake's support for `import std;` in C++23 and newer is experimental. It "
    "is meant only for experimentation and feedback to CMake developers.",
--- a/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-build/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-build/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)
--- a/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-install/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-export-no-std-install/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)
--- a/Tests/RunCMake/CXXModules/examples/import-std-no-std-property/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-no-std-property/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_no_std_property CXX)
--- a/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-build/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-build/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)
--- a/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-install/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-not-in-export-install/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)
--- a/Tests/RunCMake/CXXModules/examples/import-std-transitive/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std-transitive/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)

--- a/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
+++ b/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std CXX)
--- a/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake
+++ b/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake
@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "a9e1cf81-9932-4810-974b-6eccaf14e457")
+  "d0edc3af-4c50-42ea-a356-e2862fe7a444")

 cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
  "CxxImportStd"