cmGeneratorTarget: Include Cache now occurs per language+config

Previously only occurred per config which broke per-language
system includes.

5 files changed, 45 insertions, 0 deletions

diff --git a/Tests/IncludeDirectories/CMakeLists.txt b/Tests/IncludeDirectories/CMakeLists.txt
index eb08676..1f5b664 100644
--- a/Tests/IncludeDirectories/CMakeLists.txt
+++ b/Tests/IncludeDirectories/CMakeLists.txt
@@ -17,6 +17,7 @@ if (((CMAKE_C_COMPILER_ID STREQUAL GNU AND CMAKE_C_COMPILER_VERSION VERSION_GREA
   endif()
   if (run_sys_includes_test)
     add_subdirectory(SystemIncludeDirectories)
+    add_subdirectory(SystemIncludeDirectoriesPerLang)
   endif()
 endif()
 
diff --git a/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/CMakeLists.txt b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/CMakeLists.txt
new file mode 100644
index 0000000..70dfa01
--- /dev/null
+++ b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/CMakeLists.txt
@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.17 FATAL_ERROR)
+
+project(SystemIncludeDirectoriesPerLang)
+
+add_library(c_interface INTERFACE)
+set_target_properties(c_interface PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "$<$<COMPILE_LANGUAGE:C>:${CMAKE_CURRENT_SOURCE_DIR}>"
+  INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "$<$<COMPILE_LANGUAGE:C>:${CMAKE_CURRENT_SOURCE_DIR}>"
+)
+target_compile_options(c_interface INTERFACE "$<$<COMPILE_LANG_AND_ID:C,GNU,Clang>:-Werror=unused-variable>")
+
+add_library(cxx_interface INTERFACE)
+set_target_properties(cxx_interface PROPERTIES
+  INTERFACE_INCLUDE_DIRECTORIES "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_CURRENT_SOURCE_DIR}/cxx_system_include>"
+  INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_CURRENT_SOURCE_DIR}/cxx_system_include>"
+)
+target_compile_options(cxx_interface INTERFACE "$<$<COMPILE_LANG_AND_ID:CXX,GNU,Clang>:-Werror=unused-variable>")
+
+# The C header must come before the C++ header for this test to smoke out the
+# failure. The order of sources is how CMake determines the include cache
+# and we need it to cache on the 'bad' language first
+add_executable(consume_multi_lang_includes main.c smoke_out_includes.cxx)
+target_link_libraries(consume_multi_lang_includes PRIVATE c_interface cxx_interface)
diff --git a/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/cxx_system_include/header.h b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/cxx_system_include/header.h
new file mode 100644
index 0000000..8dcd226
--- /dev/null
+++ b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/cxx_system_include/header.h
@@ -0,0 +1,10 @@
+
+// Generate a warning in here
+
+int function_that_generates_warning(int x)
+{
+  int y = x;
+  int z = 2;
+  y -= x;
+  return y;
+}
diff --git a/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/main.c b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/main.c
new file mode 100644
index 0000000..f8b643a
--- /dev/null
+++ b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/main.c
@@ -0,0 +1,4 @@
+int main()
+{
+  return 0;
+}
diff --git a/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/smoke_out_includes.cxx b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/smoke_out_includes.cxx
new file mode 100644
index 0000000..dbfc557
--- /dev/null
+++ b/Tests/IncludeDirectories/SystemIncludeDirectoriesPerLang/smoke_out_includes.cxx
@@ -0,0 +1,7 @@
+
+#include <header.h>
+
+int empty_func()
+{
+  return function_that_generates_warning(4);
+}