Add $<LINK_LANGUAGE> generator expression

They can't be used when evaluating link libraries, but they can be
used for include directories and compile definitions. Later they can
be used for compile options.

8 files changed, 116 insertions, 0 deletions

diff --git a/Tests/CompileDefinitions/compiletest.c b/Tests/CompileDefinitions/compiletest.c
new file mode 100644
index 0000000..d7883af
--- /dev/null
+++ b/Tests/CompileDefinitions/compiletest.c
@@ -0,0 +1,19 @@
+
+#ifndef LINK_C_DEFINE
+#error Expected LINK_C_DEFINE
+#endif
+#ifndef LINK_LANGUAGE_IS_C
+#error Expected LINK_LANGUAGE_IS_C
+#endif
+
+#ifdef LINK_CXX_DEFINE
+#error Unexpected LINK_CXX_DEFINE
+#endif
+#ifdef LINK_LANGUAGE_IS_CXX
+#error Unexpected LINK_LANGUAGE_IS_CXX
+#endif
+
+int main(void)
+{
+  return 0;
+}
diff --git a/Tests/CompileDefinitions/compiletest.cpp b/Tests/CompileDefinitions/compiletest.cpp
index 7379380..7df09df 100644
--- a/Tests/CompileDefinitions/compiletest.cpp
+++ b/Tests/CompileDefinitions/compiletest.cpp
@@ -56,6 +56,21 @@ enum {
 #error Expect PREFIX_DEF2
 #endif
 
+#ifndef LINK_CXX_DEFINE
+#error Expected LINK_CXX_DEFINE
+#endif
+#ifndef LINK_LANGUAGE_IS_CXX
+#error Expected LINK_LANGUAGE_IS_CXX
+#endif
+
+#ifdef LINK_C_DEFINE
+#error Unexpected LINK_C_DEFINE
+#endif
+#ifdef LINK_LANGUAGE_IS_C
+#error Unexpected LINK_LANGUAGE_IS_C
+#endif
+
+
 // TEST_GENERATOR_EXPRESSIONS
 #endif
 
diff --git a/Tests/CompileDefinitions/compiletest_mixed_c.c b/Tests/CompileDefinitions/compiletest_mixed_c.c
new file mode 100644
index 0000000..698c989
--- /dev/null
+++ b/Tests/CompileDefinitions/compiletest_mixed_c.c
@@ -0,0 +1,19 @@
+
+#ifndef LINK_CXX_DEFINE
+#error Expected LINK_CXX_DEFINE
+#endif
+#ifndef LINK_LANGUAGE_IS_CXX
+#error Expected LINK_LANGUAGE_IS_CXX
+#endif
+
+#ifdef LINK_C_DEFINE
+#error Unexpected LINK_C_DEFINE
+#endif
+#ifdef LINK_LANGUAGE_IS_C
+#error Unexpected LINK_LANGUAGE_IS_C
+#endif
+
+void someFunc(void)
+{
+
+}
diff --git a/Tests/CompileDefinitions/compiletest_mixed_cxx.cpp b/Tests/CompileDefinitions/compiletest_mixed_cxx.cpp
new file mode 100644
index 0000000..c686854
--- /dev/null
+++ b/Tests/CompileDefinitions/compiletest_mixed_cxx.cpp
@@ -0,0 +1,19 @@
+
+#ifndef LINK_CXX_DEFINE
+#error Expected LINK_CXX_DEFINE
+#endif
+#ifndef LINK_LANGUAGE_IS_CXX
+#error Expected LINK_LANGUAGE_IS_CXX
+#endif
+
+#ifdef LINK_C_DEFINE
+#error Unexpected LINK_C_DEFINE
+#endif
+#ifdef LINK_LANGUAGE_IS_C
+#error Unexpected LINK_LANGUAGE_IS_C
+#endif
+
+int main(int argc, char **argv)
+{
+  return 0;
+}
diff --git a/Tests/CompileDefinitions/target_prop/CMakeLists.txt b/Tests/CompileDefinitions/target_prop/CMakeLists.txt
index 34be917..66a3aa6 100644
--- a/Tests/CompileDefinitions/target_prop/CMakeLists.txt
+++ b/Tests/CompileDefinitions/target_prop/CMakeLists.txt
@@ -19,9 +19,29 @@ set_property(TARGET target_prop_executable APPEND PROPERTY COMPILE_DEFINITIONS
     LETTER_LIST3=\"$<JOIN:A;B;C;D,,->\"
     LETTER_LIST4=\"$<JOIN:A;B;C;D,-,->\"
     LETTER_LIST5=\"$<JOIN:A;B;C;D,-,>\"
+    "$<$<LINK_LANGUAGE:CXX>:LINK_CXX_DEFINE>"
+    "$<$<LINK_LANGUAGE:C>:LINK_C_DEFINE>"
+    "LINK_LANGUAGE_IS_$<LINK_LANGUAGE>"
 )
 
 set_property(TARGET target_prop_executable APPEND PROPERTY COMPILE_DEFINITIONS
   BUILD_IS_DEBUG=$<CONFIG:Debug>
   BUILD_IS_NOT_DEBUG=$<NOT:$<CONFIG:Debug>>
   )
+
+add_executable(target_prop_c_executable ../compiletest.c)
+
+set_property(TARGET target_prop_c_executable APPEND PROPERTY COMPILE_DEFINITIONS
+    "$<$<LINK_LANGUAGE:CXX>:LINK_CXX_DEFINE>"
+    "$<$<LINK_LANGUAGE:C>:LINK_C_DEFINE>"
+    "LINK_LANGUAGE_IS_$<LINK_LANGUAGE>"
+    )
+
+# Resulting link language will be CXX
+add_executable(target_prop_mixed_executable ../compiletest_mixed_c.c ../compiletest_mixed_cxx.cpp)
+
+set_property(TARGET target_prop_mixed_executable APPEND PROPERTY COMPILE_DEFINITIONS
+    "$<$<LINK_LANGUAGE:CXX>:LINK_CXX_DEFINE>"
+    "$<$<LINK_LANGUAGE:C>:LINK_C_DEFINE>"
+    "LINK_LANGUAGE_IS_$<LINK_LANGUAGE>"
+    )
diff --git a/Tests/IncludeDirectories/TargetIncludeDirectories/CMakeLists.txt b/Tests/IncludeDirectories/TargetIncludeDirectories/CMakeLists.txt
index 60d4c6a..50f12ee 100644
--- a/Tests/IncludeDirectories/TargetIncludeDirectories/CMakeLists.txt
+++ b/Tests/IncludeDirectories/TargetIncludeDirectories/CMakeLists.txt
@@ -128,3 +128,19 @@ file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/prefix_foo/prefix_bar/prefix_ba
 file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/prefix_foo/prefix_bar/prefix_bat/prefix_foo_bar_bat.h" "// prefix_foo_bar_bat.h\n")
 
 target_include_directories(TargetIncludeDirectories PRIVATE "${CMAKE_CURRENT_BINARY_DIR}/prefix_$<JOIN:foo;bar;bat,/prefix_>")
+
+# Test that the language generator expressions work
+set_property(TARGET TargetIncludeDirectories
+  APPEND PROPERTY INCLUDE_DIRECTORIES
+  "$<$<LINK_LANGUAGE:C>:${CMAKE_CURRENT_BINARY_DIR}/bad>"
+  "$<$<LINK_LANGUAGE:CXX>:${CMAKE_CURRENT_BINARY_DIR}/good>"
+  "$<$<STREQUAL:$<LINK_LANGUAGE>,CXX>:${CMAKE_CURRENT_BINARY_DIR}/othergood/>"
+)
+
+add_executable(TargetIncludeDirectories_C main.c)
+set_property(TARGET TargetIncludeDirectories_C
+  APPEND PROPERTY INCLUDE_DIRECTORIES
+  "$<$<LINK_LANGUAGE:CXX>:${CMAKE_CURRENT_BINARY_DIR}/bad>"
+  "$<$<LINK_LANGUAGE:C>:${CMAKE_CURRENT_BINARY_DIR}/good>"
+  "$<$<STREQUAL:$<LINK_LANGUAGE>,C>:${CMAKE_CURRENT_BINARY_DIR}/othergood/>"
+)
diff --git a/Tests/IncludeDirectories/TargetIncludeDirectories/main.c b/Tests/IncludeDirectories/TargetIncludeDirectories/main.c
new file mode 100644
index 0000000..a597daa
--- /dev/null
+++ b/Tests/IncludeDirectories/TargetIncludeDirectories/main.c
@@ -0,0 +1,7 @@
+
+#include "common.h"
+
+int main(void)
+{
+  return 0;
+}
diff --git a/Tests/IncludeDirectories/TargetIncludeDirectories/main.cpp b/Tests/IncludeDirectories/TargetIncludeDirectories/main.cpp
index 5bb34aa..aed0bde 100644
--- a/Tests/IncludeDirectories/TargetIncludeDirectories/main.cpp
+++ b/Tests/IncludeDirectories/TargetIncludeDirectories/main.cpp
@@ -11,6 +11,7 @@
 #include "list.h"
 #include "target.h"
 #include "prefix_foo_bar_bat.h"
+#include "common.h"
 
 int main(int, char**)
 {