Genex: Enable COMPILE_LANGUAGE for COMPILE_DEFINITIONS with VS and Xcode

The set of compile flags used for a target's C and C++ sources is based
on the linker language.  By default this is always the C++ flags if any
C++ sources appear in the target, and otherwise the C flags.  Therefore
we can define the `COMPILE_LANGUAGE` generator expression in
`COMPILE_DEFINITIONS` to match the selected language.

This is not exactly the same as for other generators, but is the best VS
and Xcode can do.  It is also sufficient for many use cases since the
set of definitions for C and C++ is frequently similar but may be
distinct from those for other languages like CUDA.

Issue: #17435

17 files changed, 58 insertions, 88 deletions

diff --git a/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt b/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
index f96283d..7dc7995 100644
--- a/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
+++ b/Tests/CMakeCommands/target_compile_definitions/CMakeLists.txt
@@ -26,18 +26,18 @@ target_compile_definitions(consumer
   PRIVATE
 )
 
-if (CMAKE_GENERATOR MATCHES "Makefiles" OR CMAKE_GENERATOR MATCHES "Ninja")
-  target_sources(consumer PRIVATE
-    "${CMAKE_CURRENT_SOURCE_DIR}/consumer.c"
-  )
-  target_compile_definitions(consumer
-    PRIVATE
-      CONSUMER_LANG_$<COMPILE_LANGUAGE>
-      LANG_IS_CXX=$<COMPILE_LANGUAGE:CXX>
-      LANG_IS_C=$<COMPILE_LANGUAGE:C>
-  )
+target_sources(consumer PRIVATE
+  "${CMAKE_CURRENT_SOURCE_DIR}/consumer.c"
+)
+target_compile_definitions(consumer
+  PRIVATE
+    CONSUMER_LANG_$<COMPILE_LANGUAGE>
+    LANG_IS_CXX=$<COMPILE_LANGUAGE:CXX>
+    LANG_IS_C=$<COMPILE_LANGUAGE:C>
+)
+if(CMAKE_GENERATOR MATCHES "Visual Studio|Xcode")
   target_compile_definitions(consumer
-    PRIVATE -DTEST_LANG_DEFINES
+    PRIVATE TEST_LANG_DEFINES_FOR_VISUAL_STUDIO_OR_XCODE
   )
 endif()
 
diff --git a/Tests/CMakeCommands/target_compile_definitions/consumer.c b/Tests/CMakeCommands/target_compile_definitions/consumer.c
index 7931a6f..e134a8b 100644
--- a/Tests/CMakeCommands/target_compile_definitions/consumer.c
+++ b/Tests/CMakeCommands/target_compile_definitions/consumer.c
@@ -1,5 +1,23 @@
 
-#ifdef TEST_LANG_DEFINES
+// Visual Studio allows only one set of flags for C and C++.
+// In a target using C++ we pick the C++ flags even for C sources.
+#ifdef TEST_LANG_DEFINES_FOR_VISUAL_STUDIO_OR_XCODE
+#ifndef CONSUMER_LANG_CXX
+#error Expected CONSUMER_LANG_CXX
+#endif
+
+#ifdef CONSUMER_LANG_C
+#error Unexpected CONSUMER_LANG_C
+#endif
+
+#if !LANG_IS_CXX
+#error Expected LANG_IS_CXX
+#endif
+
+#if LANG_IS_C
+#error Unexpected LANG_IS_C
+#endif
+#else
 #ifdef CONSUMER_LANG_CXX
 #error Unexpected CONSUMER_LANG_CXX
 #endif
diff --git a/Tests/CMakeCommands/target_compile_definitions/consumer.cpp b/Tests/CMakeCommands/target_compile_definitions/consumer.cpp
index 0202c17..69ea151 100644
--- a/Tests/CMakeCommands/target_compile_definitions/consumer.cpp
+++ b/Tests/CMakeCommands/target_compile_definitions/consumer.cpp
@@ -15,7 +15,6 @@
 #error Expected DASH_D_DEFINE
 #endif
 
-#ifdef TEST_LANG_DEFINES
 #ifndef CONSUMER_LANG_CXX
 #error Expected CONSUMER_LANG_CXX
 #endif
@@ -31,7 +30,6 @@
 #if LANG_IS_C
 #error Unexpected LANG_IS_C
 #endif
-#endif
 
 int main()
 {
diff --git a/Tests/CudaOnly/WithDefs/CMakeLists.txt b/Tests/CudaOnly/WithDefs/CMakeLists.txt
index 5bd93a4..1a5599b 100644
--- a/Tests/CudaOnly/WithDefs/CMakeLists.txt
+++ b/Tests/CudaOnly/WithDefs/CMakeLists.txt
@@ -32,8 +32,8 @@ add_executable(CudaOnlyWithDefs ${main})
 
 target_compile_options(CudaOnlyWithDefs
   PRIVATE
-    -DCOMPILE_LANG_$<COMPILE_LANGUAGE>
-    -DLANG_IS_CUDA=$<COMPILE_LANGUAGE:CUDA>
+    -DFLAG_COMPILE_LANG_$<COMPILE_LANGUAGE>
+    -DFLAG_LANG_IS_CUDA=$<COMPILE_LANGUAGE:CUDA>
     -Xcompiler=-DHOST_DEFINE
     $<$<CONFIG:DEBUG>:$<BUILD_INTERFACE:${debug_compile_flags}>>
   )
@@ -41,6 +41,8 @@ target_compile_options(CudaOnlyWithDefs
 target_compile_definitions(CudaOnlyWithDefs
   PRIVATE
     $<$<CONFIG:RELEASE>:$<BUILD_INTERFACE:${release_compile_defs}>>
+    -DDEF_COMPILE_LANG_$<COMPILE_LANGUAGE>
+    -DDEF_LANG_IS_CUDA=$<COMPILE_LANGUAGE:CUDA>
   )
 
 if(APPLE)
diff --git a/Tests/CudaOnly/WithDefs/main.notcu b/Tests/CudaOnly/WithDefs/main.notcu
index bfb3577..426eb62 100644
--- a/Tests/CudaOnly/WithDefs/main.notcu
+++ b/Tests/CudaOnly/WithDefs/main.notcu
@@ -10,16 +10,28 @@
 #error "PACKED_DEFINE not defined!"
 #endif
 
-#ifndef COMPILE_LANG_CUDA
-#error "COMPILE_LANG_CUDA not defined!"
+#ifndef FLAG_COMPILE_LANG_CUDA
+#error "FLAG_COMPILE_LANG_CUDA not defined!"
 #endif
 
-#ifndef LANG_IS_CUDA
-#error "LANG_IS_CUDA not defined!"
+#ifndef FLAG_LANG_IS_CUDA
+#error "FLAG_LANG_IS_CUDA not defined!"
 #endif
 
-#if !LANG_IS_CUDA
-#error "Expected LANG_IS_CUDA"
+#if !FLAG_LANG_IS_CUDA
+#error "Expected FLAG_LANG_IS_CUDA"
+#endif
+
+#ifndef DEF_COMPILE_LANG_CUDA
+#error "DEF_COMPILE_LANG_CUDA not defined!"
+#endif
+
+#ifndef DEF_LANG_IS_CUDA
+#error "DEF_LANG_IS_CUDA not defined!"
+#endif
+
+#if !DEF_LANG_IS_CUDA
+#error "Expected DEF_LANG_IS_CUDA"
 #endif
 
 static __global__ void DetermineIfValidCudaDevice()
diff --git a/Tests/GeneratorExpression/CMakeLists.txt b/Tests/GeneratorExpression/CMakeLists.txt
index 0585d0c..4586357 100644
--- a/Tests/GeneratorExpression/CMakeLists.txt
+++ b/Tests/GeneratorExpression/CMakeLists.txt
@@ -269,10 +269,8 @@ set_property(SOURCE srcgenex_flags_COMPILE_LANGUAGE.c PROPERTY COMPILE_FLAGS "$<
 add_executable(srcgenex_defs srcgenex_defs.c)
 set_property(SOURCE srcgenex_defs.c PROPERTY COMPILE_DEFINITIONS NAME=$<TARGET_PROPERTY:NAME>)
 
-if (CMAKE_GENERATOR MATCHES "Makefiles|Ninja|Watcom WMake")
-  add_executable(srcgenex_defs_COMPILE_LANGUAGE srcgenex_defs_COMPILE_LANGUAGE.c)
-  set_property(SOURCE srcgenex_defs_COMPILE_LANGUAGE.c PROPERTY COMPILE_DEFINITIONS $<$<COMPILE_LANGUAGE:C>:NAME=$<TARGET_PROPERTY:NAME>>)
-endif()
+add_executable(srcgenex_defs_COMPILE_LANGUAGE srcgenex_defs_COMPILE_LANGUAGE.c)
+set_property(SOURCE srcgenex_defs_COMPILE_LANGUAGE.c PROPERTY COMPILE_DEFINITIONS $<$<COMPILE_LANGUAGE:C>:NAME=$<TARGET_PROPERTY:NAME>>)
 
 #-----------------------------------------------------------------------------
 # Cover test properties with generator expressions.
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-result.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-result.txt
deleted file mode 100644
index d00491f..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-result.txt
+++ /dev/null
@@ -1 +0,0 @@
-1
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-stderr-VS.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-stderr-VS.txt
deleted file mode 100644
index 42c1485..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-stderr-VS.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-CMake Error at CompileDefinitions.cmake:5 \(target_compile_definitions\):
-  Error evaluating generator expression:
-
-    \$<COMPILE_LANGUAGE:CXX>
-
-  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS and
-  file\(GENERATE\) with the Visual Studio generator.
-Call Stack \(most recent call first\):
-  CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-stderr-Xcode.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-stderr-Xcode.txt
deleted file mode 100644
index 7879a79..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions-stderr-Xcode.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-CMake Error at CompileDefinitions.cmake:5 \(target_compile_definitions\):
-  Error evaluating generator expression:
-
-    \$<COMPILE_LANGUAGE:CXX>
-
-  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS and
-  file\(GENERATE\) with the Xcode generator.
-Call Stack \(most recent call first\):
-  CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions.cmake b/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions.cmake
deleted file mode 100644
index 7935d88..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/CompileDefinitions.cmake
+++ /dev/null
@@ -1,5 +0,0 @@
-
-enable_language(CXX)
-
-add_executable(main main.cpp)
-target_compile_definitions(main PRIVATE $<$<COMPILE_LANGUAGE:CXX>:-DANYTHING>)
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-VS.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-VS.txt
index 3806ed1..0e13c48 100644
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-VS.txt
+++ b/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-VS.txt
@@ -3,7 +3,7 @@ CMake Error at IncludeDirectories.cmake:5 \(target_include_directories\):
 
     \$<COMPILE_LANGUAGE:CXX>
 
-  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS and
-  file\(GENERATE\) with the Visual Studio generator.
+  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS,
+  COMPILE_DEFINITIONS, and file\(GENERATE\) with the Visual Studio generator.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-Xcode.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-Xcode.txt
index a3fb9c5..3f86dd4 100644
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-Xcode.txt
+++ b/Tests/RunCMake/COMPILE_LANGUAGE-genex/IncludeDirectories-stderr-Xcode.txt
@@ -3,7 +3,7 @@ CMake Error at IncludeDirectories.cmake:5 \(target_include_directories\):
 
     \$<COMPILE_LANGUAGE:CXX>
 
-  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS and
-  file\(GENERATE\) with the Xcode generator.
+  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS,
+  COMPILE_DEFINITIONS, and file\(GENERATE\) with the Xcode generator.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-result.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-result.txt
deleted file mode 100644
index d00491f..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-result.txt
+++ /dev/null
@@ -1 +0,0 @@
-1
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-stderr-VS.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-stderr-VS.txt
deleted file mode 100644
index 5d19153..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-stderr-VS.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-CMake Error:
-  Error evaluating generator expression:
-
-    \$<COMPILE_LANGUAGE:CXX>
-
-  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS and
-  file\(GENERATE\) with the Visual Studio generator.
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-stderr-Xcode.txt b/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-stderr-Xcode.txt
deleted file mode 100644
index 4a4564e..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions-stderr-Xcode.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-CMake Error:
-  Error evaluating generator expression:
-
-    \$<COMPILE_LANGUAGE:CXX>
-
-  \$<COMPILE_LANGUAGE:...> may only be used for COMPILE_OPTIONS and
-  file\(GENERATE\) with the Xcode generator.
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions.cmake b/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions.cmake
deleted file mode 100644
index 3a07d7d..0000000
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/PerSourceCompileDefinitions.cmake
+++ /dev/null
@@ -1,5 +0,0 @@
-
-enable_language(CXX)
-
-add_executable(main main.cpp)
-set_property(SOURCE main.cpp PROPERTY COMPILE_DEFINITIONS $<$<COMPILE_LANGUAGE:CXX>:ANYTHING>)
diff --git a/Tests/RunCMake/COMPILE_LANGUAGE-genex/RunCMakeTest.cmake b/Tests/RunCMake/COMPILE_LANGUAGE-genex/RunCMakeTest.cmake
index 1a93dcd..9ed1b67 100644
--- a/Tests/RunCMake/COMPILE_LANGUAGE-genex/RunCMakeTest.cmake
+++ b/Tests/RunCMake/COMPILE_LANGUAGE-genex/RunCMakeTest.cmake
@@ -1,23 +1,9 @@
 include(RunCMake)
 
 if (RunCMake_GENERATOR STREQUAL "Xcode")
-    set(RunCMake-stderr-file CompileDefinitions-stderr-Xcode.txt)
-    run_cmake(CompileDefinitions)
-elseif (RunCMake_GENERATOR MATCHES "Visual Studio")
-    set(RunCMake-stderr-file CompileDefinitions-stderr-VS.txt)
-    run_cmake(CompileDefinitions)
-endif()
-if (RunCMake_GENERATOR STREQUAL "Xcode")
     set(RunCMake-stderr-file IncludeDirectories-stderr-Xcode.txt)
     run_cmake(IncludeDirectories)
 elseif (RunCMake_GENERATOR MATCHES "Visual Studio")
     set(RunCMake-stderr-file IncludeDirectories-stderr-VS.txt)
     run_cmake(IncludeDirectories)
 endif()
-if (RunCMake_GENERATOR STREQUAL "Xcode")
-    set(RunCMake-stderr-file PerSourceCompileDefinitions-stderr-Xcode.txt)
-    run_cmake(PerSourceCompileDefinitions)
-elseif (RunCMake_GENERATOR MATCHES "Visual Studio")
-    set(RunCMake-stderr-file PerSourceCompileDefinitions-stderr-VS.txt)
-    run_cmake(PerSourceCompileDefinitions)
-endif()