Merge topic 'offer_compiler_lang_generator_expression'

e214abdaab Genex: Add COMPILE_LANG_AND_ID generator expression
f84ed796a2 Docs: Generator-expressions remove usage of `CMake-id`

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3300

2 files changed, 53 insertions, 10 deletions

diff --git a/Help/manual/cmake-generator-expressions.7.rst b/Help/manual/cmake-generator-expressions.7.rst
index ce62893..f2e6597 100644
--- a/Help/manual/cmake-generator-expressions.7.rst
+++ b/Help/manual/cmake-generator-expressions.7.rst
@@ -111,22 +111,22 @@ Variable Queries
   this expression when it is evaluated on a property on an :prop_tgt:`IMPORTED`
   target.
 ``$<PLATFORM_ID:platform_id>``
-  ``1`` if the CMake-id of the platform matches ``platform_id``
+  ``1`` if the CMake's platform id matches ``platform_id``
   otherwise ``0``.
   See also the :variable:`CMAKE_SYSTEM_NAME` variable.
 ``$<C_COMPILER_ID:compiler_id>``
-  ``1`` if the CMake-id of the C compiler matches ``compiler_id``,
+  ``1`` if the CMake's compiler id of the C compiler matches ``compiler_id``,
   otherwise ``0``.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<CXX_COMPILER_ID:compiler_id>``
-  ``1`` if the CMake-id of the CXX compiler matches ``compiler_id``,
+  ``1`` if the CMake's compiler id of the CXX compiler matches ``compiler_id``,
   otherwise ``0``.
 ``$<CUDA_COMPILER_ID:compiler_id>``
-  ``1`` if the CMake-id of the CUDA compiler matches ``compiler_id``,
+  ``1`` if the CMake's compiler id of the CUDA compiler matches ``compiler_id``,
   otherwise ``0``.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<Fortran_COMPILER_ID:compiler_id>``
-  ``1`` if the CMake-id of the Fortran compiler matches ``compiler_id``,
+  ``1`` if the CMake's compiler id of the Fortran compiler matches ``compiler_id``,
   otherwise ``0``.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<C_COMPILER_VERSION:version>``
@@ -158,6 +158,42 @@ Variable Queries
 
 .. _`Boolean COMPILE_LANGUAGE Generator Expression`:
 
+``$<COMPILE_LANG_AND_ID:language,compiler_id>``
+  ``1`` when the language used for compilation unit matches ``language`` and
+  the CMake's compiler id of the language compiler matches ``compiler_id``,
+  otherwise ``0``. This expression is a short form for the combination of
+  ``$<COMPILE_LANGUAGE:language>`` and ``$<LANG_COMPILER_ID:compiler_id>``.
+  This expression may be used to specify compile options,
+  compile definitions, and include directories for source files of a
+  particular language and compiler combination in a target. For example:
+
+  .. code-block:: cmake
+
+    add_executable(myapp main.cpp foo.c bar.cpp zot.cu)
+    target_compile_definitions(myapp
+      PRIVATE $<$<COMPILE_LANG_AND_ID:CXX,Clang>:COMPILING_CXX_WITH_CLANG>
+              $<$<COMPILE_LANG_AND_ID:CXX,Intel>:COMPILING_CXX_WITH_INTEL>
+              $<$<COMPILE_LANG_AND_ID:C,Clang>:COMPILING_C_WITH_CLANG>
+    )
+
+  This specifies the use of different compile definitions based on both
+  the compiler id and compilation language. This example will have a
+  ``COMPILING_CXX_WITH_CLANG`` compile definition when Clang is the CXX
+  compiler, and ``COMPILING_CXX_WITH_INTEL`` when Intel is the CXX compiler.
+  Likewise when the C compiler is Clang it will only see the  ``COMPILING_C_WITH_CLANG``
+  definition.
+
+  Without the ``COMPILE_LANG_AND_ID`` generator expression the same logic
+  would be expressed as:
+
+  .. code-block:: cmake
+
+    target_compile_definitions(myapp
+      PRIVATE $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:Clang>>:COMPILING_CXX_WITH_CLANG>
+              $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:Intel>>:COMPILING_CXX_WITH_INTEL>
+              $<$<AND:$<COMPILE_LANGUAGE:C>,$<C_COMPILER_ID:Clang>>:COMPILING_C_WITH_CLANG>
+    )
+
 ``$<COMPILE_LANGUAGE:language>``
   ``1`` when the language used for compilation unit matches ``language``,
   otherwise ``0``.  This expression may be used to specify compile options,
@@ -348,19 +384,19 @@ Variable Queries
 ``$<CONFIGURATION>``
   Configuration name. Deprecated since CMake 3.0. Use ``CONFIG`` instead.
 ``$<PLATFORM_ID>``
-  The CMake-id of the platform.
+  The current system's CMake platform id.
   See also the :variable:`CMAKE_SYSTEM_NAME` variable.
 ``$<C_COMPILER_ID>``
-  The CMake-id of the C compiler used.
+  The CMake's compiler id of the C compiler used.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<CXX_COMPILER_ID>``
-  The CMake-id of the CXX compiler used.
+  The CMake's compiler id of the CXX compiler used.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<CUDA_COMPILER_ID>``
-  The CMake-id of the CUDA compiler used.
+  The CMake's compiler id of the CUDA compiler used.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<Fortran_COMPILER_ID>``
-  The CMake-id of the Fortran compiler used.
+  The CMake's compiler id of the Fortran compiler used.
   See also the :variable:`CMAKE_<LANG>_COMPILER_ID` variable.
 ``$<C_COMPILER_VERSION>``
   The version of the C compiler used.
diff --git a/Help/release/dev/genex-COMPILE_LANG_AND_ID.rst b/Help/release/dev/genex-COMPILE_LANG_AND_ID.rst
new file mode 100644
index 0000000..27e0ebd
--- /dev/null
+++ b/Help/release/dev/genex-COMPILE_LANG_AND_ID.rst
@@ -0,0 +1,7 @@
+genex-COMPILE_LANG_AND_ID
+--------------------------
+
+* A new ``COMPILE_LANG_AND_ID`` generator expression was introduced to
+  allow specification of compile options for target files based on the
+  :variable:`CMAKE_<LANG>_COMPILER_ID`  and :prop_sf:`LANGUAGE` and of
+  each source file.