[CMake] Copy the generated __config header into build directory

When the generated __config file is being used, it is currently only
copied during installation process. However, that means that the file
that gets copied into LLVM build directory is the vanilla __config file,
and any parts of the build that depend on the just built toolchain like
sanitizers will get that instead of the generated version. To avoid this
issue, we need to copy the generated header into the LLVM build
directory as well.

Differential Revision: https://reviews.llvm.org/D43797

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@327194 91177308-0d34-0410-b5e6-96231b3b80d8

include/CMakeLists.txt

diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index b98e092..5bf92f0 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -2,6 +2,23 @@
   set(LIBCXX_SUPPORT_HEADER_PATTERN PATTERN "support" EXCLUDE)
 endif()
 
+if (LIBCXX_NEEDS_SITE_CONFIG)
+  # Generate a custom __config header. The new header is created
+  # by prepending __config_site to the current __config header.
+  add_custom_command(OUTPUT ${LIBCXX_BINARY_DIR}/__generated_config
+    COMMAND ${PYTHON_EXECUTABLE} ${LIBCXX_SOURCE_DIR}/utils/cat_files.py
+      ${LIBCXX_BINARY_DIR}/__config_site
+      ${LIBCXX_SOURCE_DIR}/include/__config
+      -o ${LIBCXX_BINARY_DIR}/__generated_config
+    DEPENDS ${LIBCXX_SOURCE_DIR}/include/__config
+            ${LIBCXX_BINARY_DIR}/__config_site
+  )
+  # Add a target that executes the generation commands.
+  add_custom_target(generate_config_header ALL
+    DEPENDS ${LIBCXX_BINARY_DIR}/__generated_config)
+  set(generated_config_deps generate_config_header)
+endif()
+
 set(LIBCXX_HEADER_PATTERN
   PATTERN "*"
   PATTERN "CMakeLists.txt" EXCLUDE
@@ -16,6 +33,15 @@
     FILES_MATCHING
     ${LIBCXX_HEADER_PATTERN}
     )
+
+  if (LIBCXX_NEEDS_SITE_CONFIG)
+    # Copy the generated header as __config into build directory.
+    add_custom_command(
+        TARGET generate_config_header POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy
+                ${LIBCXX_BINARY_DIR}/__generated_config
+                ${LLVM_BINARY_DIR}/include/c++/v1/__config)
+  endif()
 endif()
 
 if (LIBCXX_INSTALL_HEADERS)
@@ -28,20 +54,6 @@
   )
 
   if (LIBCXX_NEEDS_SITE_CONFIG)
-    # Generate and install a custom __config header. The new header is created
-    # by  prepending __config_site to the current __config header.
-    add_custom_command(OUTPUT ${LIBCXX_BINARY_DIR}/__generated_config
-      COMMAND ${PYTHON_EXECUTABLE} ${LIBCXX_SOURCE_DIR}/utils/cat_files.py
-        ${LIBCXX_BINARY_DIR}/__config_site
-        ${LIBCXX_SOURCE_DIR}/include/__config
-        -o ${LIBCXX_BINARY_DIR}/__generated_config
-      DEPENDS ${LIBCXX_SOURCE_DIR}/include/__config
-              ${LIBCXX_BINARY_DIR}/__config_site
-    )
-    # Add a target that executes the generation commands.
-    add_custom_target(generate_config_header ALL
-      DEPENDS ${LIBCXX_BINARY_DIR}/__generated_config)
-    set(generated_config_deps generate_config_header)
     # Install the generated header as __config.
     install(FILES ${LIBCXX_BINARY_DIR}/__generated_config
       DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1

lib/CMakeLists.txt

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 5d71111..30fdc30 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -283,7 +283,7 @@
 endif()
 
 # Add a meta-target for both libraries.
-add_custom_target(cxx DEPENDS ${LIBCXX_TARGETS})
+add_custom_target(cxx DEPENDS ${LIBCXX_TARGETS} ${generated_config_deps})
 
 if (LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY)
   file(GLOB LIBCXX_EXPERIMENTAL_SOURCES ../src/experimental/*.cpp)