Index: llvm/cmake/modules/AddLLVM.cmake
===================================================================
--- llvm/cmake/modules/AddLLVM.cmake
+++ llvm/cmake/modules/AddLLVM.cmake
@@ -1029,6 +1029,10 @@
     target_link_libraries(${name} PRIVATE ${LLVM_PTHREAD_LIB})
   endif()
 
+  if(CXX_LINKER_SUPPORTS_LLVM_LIBC)
+    target_link_libraries(${name} PRIVATE llvmlibc)
+  endif()
+
   llvm_codesign(${name} ENTITLEMENTS ${ARG_ENTITLEMENTS} BUNDLE_PATH ${ARG_BUNDLE_PATH})
 endmacro(add_llvm_executable name)
 
Index: llvm/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -1300,3 +1300,13 @@
 
 set(LLVM_THIRD_PARTY_DIR  ${CMAKE_CURRENT_SOURCE_DIR}/../third-party CACHE STRING
     "Directory containing third party software used by LLVM (e.g. googletest)")
+
+set(LLVM_ENABLE_LLVM_LIBC OFF CACHE BOOL "Set to on to link all LLVM executables against LLVM libc, assuming it is accessible by the host compiler")
+
+if(LLVM_ENABLE_LLVM_LIBC)
+  include(CheckCXXCompilerFlag)
+  llvm_check_linker_flag(CXX "-lllvmlibc" CXX_LINKER_SUPPORTS_LLVM_LIBC)
+  if(NOT CXX_LINKER_SUPPORTS_LLVM_LIBC)
+    message(WARNING "Unable to link against LLVM libc. LLVM will be built without linking against the LLVM libc overlay.")
+  endif()
+endif()
Index: llvm/docs/CMake.rst
===================================================================
--- llvm/docs/CMake.rst
+++ llvm/docs/CMake.rst
@@ -509,6 +509,11 @@
   passed to invocations of both so that the project is built using libc++
   instead of stdlibc++. Defaults to OFF.
 
+**LLVM_ENABLE_LLVM_LIBC**: BOOL
+  If the LLVM libc overlay is installed in a location where the host linker
+  can access it, all built executables will be linked against the LLVM libc
+  overlay before linking against the system libc. Defaults to OFF.
+
 **LLVM_ENABLE_LIBPFM**:BOOL
   Enable building with libpfm to support hardware counter measurements in LLVM
   tools.