refactor(cmake): clean up toolchain and CMakeLists separation

- toolchain.cmake: only clang/lld specific setup (compiler paths, LLVM
  tools, -fuse-ld=lld)
- Promote -ffunction-sections/-fdata-sections and platform linker flags
  (gc-sections, dead_strip, static-libstdc++) to global scope so
  FetchContent deps also benefit from dead code elimination
- Promote _LIBCPP_DISABLE_AVAILABILITY to global scope
- Simplify clice_options to only project-specific settings: -fno-rtti,
  -fno-exceptions, warnings, compile definitions, Win32 system libs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 16bit-ykiko

CMakeLists.txt

@@ -14,7 +14,27 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/bin")
 
 option(CLICE_ENABLE_LTO "Enable ThinLTO for all targets" OFF)
 
-# Make sure all third libraries are affected by ABI related options
+# Global flags that apply to all targets (including FetchContent dependencies).
+if(NOT MSVC)
+    add_compile_options(-ffunction-sections -fdata-sections)
+endif()
+
+if(APPLE)
+    # https://conda-forge.org/docs/maintainer/knowledge_base/#newer-c-features-with-old-sdk
+    add_compile_definitions(_LIBCPP_DISABLE_AVAILABILITY=1)
+endif()
+
+if(WIN32)
+    string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,/OPT:REF")
+    string(APPEND CMAKE_SHARED_LINKER_FLAGS " -Wl,/OPT:REF")
+elseif(APPLE)
+    string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,-dead_strip")
+    string(APPEND CMAKE_SHARED_LINKER_FLAGS " -Wl,-dead_strip")
+else()
+    string(APPEND CMAKE_EXE_LINKER_FLAGS " -static-libstdc++ -static-libgcc -Wl,--gc-sections")
+    string(APPEND CMAKE_SHARED_LINKER_FLAGS " -Wl,--gc-sections")
+endif()
+
 if(CLICE_USE_LIBCXX)
     string(APPEND CMAKE_CXX_FLAGS " -stdlib=libc++")
     string(APPEND CMAKE_EXE_LINKER_FLAGS " -stdlib=libc++")
@@ -33,7 +53,6 @@ if(CMAKE_BUILD_TYPE STREQUAL "Debug")
     add_compile_options(-fsanitize=address)
 
     if(CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "MSVC")
-        # clang-cl (MSVC frontend): manually link ASan runtime.
         execute_process(
             COMMAND ${CMAKE_CXX_COMPILER} --print-resource-dir
             OUTPUT_VARIABLE CLANG_RESOURCE_DIR
@@ -47,81 +66,50 @@ if(CMAKE_BUILD_TYPE STREQUAL "Debug")
         list(APPEND ASAN_LINK_FLAGS "/wholearchive:clang_rt.asan_dynamic_runtime_thunk-x86_64.lib")
 
         foreach(flag ${ASAN_LINK_FLAGS})
-            set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}")
-            set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${flag}")
-            set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${flag}")
+            string(APPEND CMAKE_EXE_LINKER_FLAGS " ${flag}")
+            string(APPEND CMAKE_SHARED_LINKER_FLAGS " ${flag}")
+            string(APPEND CMAKE_MODULE_LINKER_FLAGS " ${flag}")
         endforeach()
     else()
-        # GNU frontend (clang++/gcc): -fsanitize=address handles linking automatically.
         string(APPEND CMAKE_EXE_LINKER_FLAGS " -fsanitize=address")
         string(APPEND CMAKE_SHARED_LINKER_FLAGS " -fsanitize=address")
     endif()
 
     if(WIN32)
-        # Disable Identical COMDAT Folding in Debug to avoid ASan ODR false positives.
         string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,/OPT:NOICF")
         string(APPEND CMAKE_SHARED_LINKER_FLAGS " -Wl,/OPT:NOICF")
     endif()
 endif()
 
-if(APPLE)
-    # https://conda-forge.org/docs/maintainer/knowledge_base/#newer-c-features-with-old-sdk
-    string(APPEND CMAKE_CXX_FLAGS " -D_LIBCPP_DISABLE_AVAILABILITY=1")
-endif()
-
 include("${PROJECT_SOURCE_DIR}/cmake/package.cmake")
 
+# Project-specific options (not applied to third-party deps).
 add_library(clice_options INTERFACE)
 
-if(CLICE_ENABLE_TEST)
-    target_compile_definitions(clice_options INTERFACE CLICE_ENABLE_TEST=1)
-endif()
-
-if(CLICE_CI_ENVIRONMENT)
-    target_compile_definitions(clice_options INTERFACE CLICE_CI_ENVIRONMENT=1)
-endif()
-
-if(WIN32)
-    target_link_libraries(clice_options INTERFACE version ntdll)
-endif()
-
-if(WIN32)
-    set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreadedDLL")
-    target_link_options(clice_options INTERFACE
-        -fuse-ld=lld-link
-        -Wl,/OPT:REF
-        #,/OPT:NOICF
-    )
-elseif(APPLE)
-    target_link_options(clice_options INTERFACE
-        -fuse-ld=lld
-        -Wl,-dead_strip
-    )
-elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    target_link_options(clice_options INTERFACE
-        -fuse-ld=lld
-        -static-libstdc++ -static-libgcc
-        -Wl,--gc-sections
-    )
-endif()
-
 if(MSVC OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND
          CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "MSVC"))
-    target_compile_options(clice_options INTERFACE
-        /GR-
-        /EHsc-
-        /Zc:preprocessor
-    )
+    target_compile_options(clice_options INTERFACE /GR- /EHsc- /Zc:preprocessor)
 else()
     target_compile_options(clice_options INTERFACE
         -fno-rtti
+        -fno-exceptions
         -Wno-deprecated-declarations
-        -ffunction-sections
-        -fdata-sections
         $<$<COMPILE_LANG_AND_ID:CXX,Clang,AppleClang>:-Wno-undefined-inline>
     )
 endif()
 
+if(WIN32)
+    target_link_libraries(clice_options INTERFACE version ntdll)
+endif()
+
+if(CLICE_ENABLE_TEST)
+    target_compile_definitions(clice_options INTERFACE CLICE_ENABLE_TEST=1)
+endif()
+
+if(CLICE_CI_ENVIRONMENT)
+    target_compile_definitions(clice_options INTERFACE CLICE_CI_ENVIRONMENT=1)
+endif()
+
 set(FBS_SCHEMA_FILE "${PROJECT_SOURCE_DIR}/src/index/schema.fbs")
 set(GENERATED_HEADER "${PROJECT_BINARY_DIR}/generated/schema_generated.h")
 

cmake/toolchain.cmake

@@ -1,36 +1,39 @@
 cmake_minimum_required(VERSION 3.30)
 
-set(CMAKE_C_COMPILER clang CACHE STRING "C compiler")
-set(CMAKE_CXX_COMPILER clang++ CACHE STRING "C++ compiler")
-set(AR_PROGRAM_NAME "llvm-ar")
-set(CMAKE_EXE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "Executable linker flags")
-set(CMAKE_SHARED_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "Shared library linker flags")
-set(CMAKE_MODULE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "Module linker flags")
+set(CMAKE_C_COMPILER clang CACHE STRING "")
+set(CMAKE_CXX_COMPILER clang++ CACHE STRING "")
 
-if(WIN32)
-    set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreadedDLL" CACHE STRING "MSVC runtime")
-endif()
-
-find_program(LLVM_AR_PATH ${AR_PROGRAM_NAME})
+find_program(LLVM_AR_PATH "llvm-ar")
 if(LLVM_AR_PATH)
-    set(CMAKE_AR "${LLVM_AR_PATH}" CACHE FILEPATH "Archiver")
-    set(CMAKE_C_COMPILER_AR "${LLVM_AR_PATH}" CACHE FILEPATH "C archiver")
-    set(CMAKE_CXX_COMPILER_AR "${LLVM_AR_PATH}" CACHE FILEPATH "C++ archiver")
+    set(CMAKE_AR "${LLVM_AR_PATH}" CACHE FILEPATH "")
+    set(CMAKE_C_COMPILER_AR "${LLVM_AR_PATH}" CACHE FILEPATH "")
+    set(CMAKE_CXX_COMPILER_AR "${LLVM_AR_PATH}" CACHE FILEPATH "")
 endif()
 
 find_program(LLVM_RANLIB_PATH "llvm-ranlib")
 if(LLVM_RANLIB_PATH)
-    set(CMAKE_RANLIB "${LLVM_RANLIB_PATH}" CACHE FILEPATH "Ranlib")
-    set(CMAKE_C_COMPILER_RANLIB "${LLVM_RANLIB_PATH}" CACHE FILEPATH "C ranlib")
-    set(CMAKE_CXX_COMPILER_RANLIB "${LLVM_RANLIB_PATH}" CACHE FILEPATH "C++ ranlib")
+    set(CMAKE_RANLIB "${LLVM_RANLIB_PATH}" CACHE FILEPATH "")
+    set(CMAKE_C_COMPILER_RANLIB "${LLVM_RANLIB_PATH}" CACHE FILEPATH "")
+    set(CMAKE_CXX_COMPILER_RANLIB "${LLVM_RANLIB_PATH}" CACHE FILEPATH "")
 endif()
 
 find_program(LLVM_NM_PATH "llvm-nm")
 if(LLVM_NM_PATH)
-    set(CMAKE_NM "${LLVM_NM_PATH}" CACHE FILEPATH "Symbol lister")
+    set(CMAKE_NM "${LLVM_NM_PATH}" CACHE FILEPATH "")
 endif()
 
 find_program(LLVM_RC_PATH "llvm-rc")
 if(LLVM_RC_PATH)
-    set(CMAKE_RC_COMPILER "${LLVM_RC_PATH}" CACHE FILEPATH "Resource compiler")
+    set(CMAKE_RC_COMPILER "${LLVM_RC_PATH}" CACHE FILEPATH "")
+endif()
+
+if(WIN32)
+    set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreadedDLL" CACHE STRING "")
+    set(CMAKE_EXE_LINKER_FLAGS_INIT "-fuse-ld=lld-link")
+    set(CMAKE_SHARED_LINKER_FLAGS_INIT "-fuse-ld=lld-link")
+    set(CMAKE_MODULE_LINKER_FLAGS_INIT "-fuse-ld=lld-link")
+else()
+    set(CMAKE_EXE_LINKER_FLAGS_INIT "-fuse-ld=lld")
+    set(CMAKE_SHARED_LINKER_FLAGS_INIT "-fuse-ld=lld")
+    set(CMAKE_MODULE_LINKER_FLAGS_INIT "-fuse-ld=lld")
 endif()