[llvm-branch-commits] [llvm] 7aa3dbc - Revert "Remember LLVM_ENABLE_LIBCXX setting in installed configuration (#139712)"

[via llvm-branch-commits]

Author: gulfemsavrun
Date: 2025-08-15T16:00:12-07:00
New Revision: 7aa3dbcae91ade86e362fa6ef6a739f839490cbd

URL: https://github.com/llvm/llvm-project/commit/7aa3dbcae91ade86e362fa6ef6a739f839490cbd
DIFF: https://github.com/llvm/llvm-project/commit/7aa3dbcae91ade86e362fa6ef6a739f839490cbd.diff

LOG: Revert "Remember LLVM_ENABLE_LIBCXX setting in installed configuration (#139712)"

This reverts commit b010b7ea89fdb870024b94913b2b784ce1f4f8d4.

Added: 
    

Modified: 
    llvm/cmake/modules/HandleLLVMStdlib.cmake
    llvm/cmake/modules/LLVMConfig.cmake.in

Removed: 
    


################################################################################
diff  --git a/llvm/cmake/modules/HandleLLVMStdlib.cmake b/llvm/cmake/modules/HandleLLVMStdlib.cmake
index dda1caa846dcb..a7e138aa0789b 100644
--- a/llvm/cmake/modules/HandleLLVMStdlib.cmake
+++ b/llvm/cmake/modules/HandleLLVMStdlib.cmake
@@ -2,7 +2,6 @@
 # if the user has requested it.
 
 include(DetermineGCCCompatible)
-include(CheckIncludeFiles)
 
 if(NOT DEFINED LLVM_STDLIB_HANDLED)
   set(LLVM_STDLIB_HANDLED ON)
@@ -20,17 +19,7 @@ if(NOT DEFINED LLVM_STDLIB_HANDLED)
     if(LLVM_COMPILER_IS_GCC_COMPATIBLE)
       check_cxx_compiler_flag("-stdlib=libc++" CXX_COMPILER_SUPPORTS_STDLIB)
       check_linker_flag(CXX "-stdlib=libc++" CXX_LINKER_SUPPORTS_STDLIB)
-
-      # Check whether C++ include files are available
-      # runtimes/CMakeLists.txt adds -nostdlib++ and -nostdinc++ to
-      # CMAKE_REQUIRED_FLAGS, which are incompatible with -stdlib=libc++; use
-      # a fresh CMAKE_REQUIRED_FLAGS environment.
-      cmake_push_check_state(RESET)
-      set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -stdlib=libc++")
-      check_include_files("chrono" CXX_COMPILER_SUPPORTS_STDLIB_CHRONO LANGUAGE CXX)
-      cmake_pop_check_state()
-
-      if(CXX_COMPILER_SUPPORTS_STDLIB AND CXX_LINKER_SUPPORTS_STDLIB AND CXX_COMPILER_SUPPORTS_STDLIB_CHRONO)
+      if(CXX_COMPILER_SUPPORTS_STDLIB AND CXX_LINKER_SUPPORTS_STDLIB)
         append("-stdlib=libc++"
           CMAKE_CXX_FLAGS CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS
           CMAKE_MODULE_LINKER_FLAGS)

diff  --git a/llvm/cmake/modules/LLVMConfig.cmake.in b/llvm/cmake/modules/LLVMConfig.cmake.in
index c39c33f0c7793..c15b9576cd5d5 100644
--- a/llvm/cmake/modules/LLVMConfig.cmake.in
+++ b/llvm/cmake/modules/LLVMConfig.cmake.in
@@ -55,8 +55,6 @@ endif()
 
 set(LLVM_ENABLE_RTTI @LLVM_ENABLE_RTTI@)
 
-set(LLVM_ENABLE_LIBCXX @LLVM_ENABLE_LIBCXX@)
-
 set(LLVM_ENABLE_LIBEDIT @HAVE_LIBEDIT@)
 if(LLVM_ENABLE_LIBEDIT)
   find_package(LibEdit)