[CMake] Don't copy headers on fully standalone

In r280108 I tried to make the headers copy relative to LLVM_BINARY_DIR, and the intent was that it would only happen on in-tree builds or runtimes directory builds. It didn't actually work that way.

This patch adds a check for CMAKE_SOURCE_DIR being equal to CMAKE_CURRENT_SOURCE_DIR. In this case we set a variable LIBCXX_USING_INSTLLED_LLVM. This doesn't necessarily mean the LLVM is installed (it could be a build directory), but it means we need to treat the LLVM directory as read-only.

llvm-svn: 280400

1 files changed, 9 insertions, 1 deletions

diff --git a/libcxx/cmake/Modules/HandleOutOfTreeLLVM.cmake b/libcxx/cmake/Modules/HandleOutOfTreeLLVM.cmake
index 934dfcd7bb1..349d234e198 100644
--- a/libcxx/cmake/Modules/HandleOutOfTreeLLVM.cmake
+++ b/libcxx/cmake/Modules/HandleOutOfTreeLLVM.cmake
@@ -61,8 +61,16 @@ macro(find_llvm_parts)
   set(LLVM_FOUND ON)
 endmacro(find_llvm_parts)
 
+# If this is a standalone build not running as an external project of LLVM
+# we need to later make some decisions differently.
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  # The intent is that this doesn't necessarily mean the LLVM is installed (it
+  # could be a build directory), but it means we need to treat the LLVM
+  # directory as read-only.
+  set(LIBCXX_USING_INSTLLED_LLVM 1)
+endif()
 
-if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR LIBCXX_STANDALONE_BUILD)
+if (LIBCXX_USING_INSTLLED_LLVM OR LIBCXX_STANDALONE_BUILD)
   set(LIBCXX_STANDALONE_BUILD 1)
   message(STATUS "Configuring for standalone build.")