From a9b851763854ffb21e9569f18e0f34b4f661fbeb Mon Sep 17 00:00:00 2001
From: LoveSy <shana@zju.edu.cn>
Date: Tue, 4 Jun 2024 21:35:43 +0800
Subject: [PATCH] Use native c++ module support from CMake

also fix some clang compilation issues when using c++ modules
---
 CMakeLists.txt       | 90 +++++++++++++++++++++++---------------------
 include/fmt/format.h |  6 ++-
 2 files changed, 52 insertions(+), 44 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9b79776fa42e..bd9896676d83 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.8...3.26)
+cmake_minimum_required(VERSION 3.8...3.28)
 
 # Fallback for using newer policies on CMake <3.12.
 if (${CMAKE_VERSION} VERSION_LESS 3.12)
@@ -62,48 +62,52 @@ function(add_module_library name)
     target_compile_options(${name} PUBLIC -fmodules-ts)
   endif ()
 
-  # `std` is affected by CMake options and may be higher than C++20.
-  get_target_property(std ${name} CXX_STANDARD)
-
-  if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    set(pcms)
-    foreach (src ${sources})
-      get_filename_component(pcm ${src} NAME_WE)
-      set(pcm ${pcm}.pcm)
-
-      # Propagate -fmodule-file=*.pcm to targets that link with this library.
-      target_compile_options(
-        ${name} PUBLIC -fmodule-file=${CMAKE_CURRENT_BINARY_DIR}/${pcm})
-
-      # Use an absolute path to prevent target_link_libraries prepending -l
-      # to it.
-      set(pcms ${pcms} ${CMAKE_CURRENT_BINARY_DIR}/${pcm})
-      add_custom_command(
-        OUTPUT ${pcm}
-        COMMAND ${CMAKE_CXX_COMPILER}
-                -std=c++${std} -x c++-module --precompile -c
-                -o ${pcm} ${CMAKE_CURRENT_SOURCE_DIR}/${src}
-                "-I$<JOIN:$<TARGET_PROPERTY:${name},INCLUDE_DIRECTORIES>,;-I>"
-        # Required by the -I generator expression above.
-        COMMAND_EXPAND_LISTS
-        DEPENDS ${src})
-    endforeach ()
-
-    # Add .pcm files as sources to make sure they are built before the library.
-    set(sources)
-    foreach (pcm ${pcms})
-      get_filename_component(pcm_we ${pcm} NAME_WE)
-      set(obj ${pcm_we}.o)
-      # Use an absolute path to prevent target_link_libraries prepending -l.
-      set(sources ${sources} ${pcm} ${CMAKE_CURRENT_BINARY_DIR}/${obj})
-      add_custom_command(
-        OUTPUT ${obj}
-        COMMAND ${CMAKE_CXX_COMPILER} $<TARGET_PROPERTY:${name},COMPILE_OPTIONS>
-                -c -o ${obj} ${pcm}
-        DEPENDS ${pcm})
-    endforeach ()
-  endif ()
-  target_sources(${name} PRIVATE ${sources})
+  if (CMAKE_VERSION VERSION_LESS 3.28)
+    # `std` is affected by CMake options and may be higher than C++20.
+    get_target_property(std ${name} CXX_STANDARD)
+
+    if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+      set(pcms)
+      foreach (src ${sources})
+        get_filename_component(pcm ${src} NAME_WE)
+        set(pcm ${pcm}.pcm)
+
+        # Propagate -fmodule-file=*.pcm to targets that link with this library.
+        target_compile_options(
+          ${name} PUBLIC -fmodule-file=${CMAKE_CURRENT_BINARY_DIR}/${pcm})
+
+        # Use an absolute path to prevent target_link_libraries prepending -l
+        # to it.
+        set(pcms ${pcms} ${CMAKE_CURRENT_BINARY_DIR}/${pcm})
+        add_custom_command(
+          OUTPUT ${pcm}
+          COMMAND ${CMAKE_CXX_COMPILER}
+                  -std=c++${std} -x c++-module --precompile -c
+                  -o ${pcm} ${CMAKE_CURRENT_SOURCE_DIR}/${src}
+                  "-I$<JOIN:$<TARGET_PROPERTY:${name},INCLUDE_DIRECTORIES>,;-I>"
+          # Required by the -I generator expression above.
+          COMMAND_EXPAND_LISTS
+          DEPENDS ${src})
+      endforeach ()
+
+      # Add .pcm files as sources to make sure they are built before the library.
+      set(sources)
+      foreach (pcm ${pcms})
+        get_filename_component(pcm_we ${pcm} NAME_WE)
+        set(obj ${pcm_we}.o)
+        # Use an absolute path to prevent target_link_libraries prepending -l.
+        set(sources ${sources} ${pcm} ${CMAKE_CURRENT_BINARY_DIR}/${obj})
+        add_custom_command(
+          OUTPUT ${obj}
+          COMMAND ${CMAKE_CXX_COMPILER} $<TARGET_PROPERTY:${name},COMPILE_OPTIONS>
+                  -c -o ${obj} ${pcm}
+          DEPENDS ${pcm})
+      endforeach ()
+    endif ()
+    target_sources(${name} PRIVATE ${sources})
+  else()
+    target_sources(${name} PUBLIC FILE_SET CXX_MODULES FILES ${sources})
+  endif()
 endfunction()
 
 include(CMakeParseArguments)
diff --git a/include/fmt/format.h b/include/fmt/format.h
index d3e196c94cd7..fa8debc13b71 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -1069,6 +1069,8 @@ template <typename Locale> class format_facet : public Locale::facet {
   }
 };
 
+FMT_END_EXPORT
+
 namespace detail {
 
 // Returns true if value is negative, false otherwise.
@@ -3865,6 +3867,7 @@ FMT_API void report_error(format_func func, int error_code,
                           const char* message) noexcept;
 }  // namespace detail
 
+FMT_BEGIN_EXPORT
 FMT_API auto vsystem_error(int error_code, string_view format_str,
                            format_args args) -> std::system_error;
 
@@ -4285,6 +4288,8 @@ extern template FMT_API auto decimal_point_impl(locale_ref) -> char;
 extern template FMT_API auto decimal_point_impl(locale_ref) -> wchar_t;
 #endif  // FMT_HEADER_ONLY
 
+FMT_END_EXPORT
+
 template <typename T, typename Char, type TYPE>
 template <typename FormatContext>
 FMT_CONSTEXPR FMT_INLINE auto native_formatter<T, Char, TYPE>::format(
@@ -4300,7 +4305,6 @@ FMT_CONSTEXPR FMT_INLINE auto native_formatter<T, Char, TYPE>::format(
   return write<Char>(ctx.out(), val, specs, ctx.locale());
 }
 
-FMT_END_EXPORT
 }  // namespace detail
 
 FMT_BEGIN_EXPORT