pybind11Tools: Use interface target library when able

Author: EricCousineau-TRI

docs/compiling.rst

@@ -189,6 +189,11 @@ to an independently constructed (through ``add_library``, not
     Studio (``/bigobj``).  The :ref:`FAQ <faq:symhidden>` contains an
     explanation on why these are needed.
 
+.. note::
+
+    ``pybind11_add_module`` will use this interface library target in addition
+    to the above compiler flags if using a version of CMake greater than 3.0.
+
 Embedding the Python interpreter
 --------------------------------
 

tools/pybind11Tools.cmake

@@ -130,26 +130,39 @@ function(pybind11_add_module target_name)
 
   add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS})
 
-  target_include_directories(${target_name}
-    PRIVATE ${PYBIND11_INCLUDE_DIR}  # from project CMakeLists.txt
-    PRIVATE ${pybind11_INCLUDE_DIR}  # from pybind11Config
-    PRIVATE ${PYTHON_INCLUDE_DIRS})
+  if(TARGET pybind11::module)
+    # Use interface target library.
+    target_link_libraries(${target_name} PRIVATE pybind11::module)
+  else()
+    target_include_directories(${target_name}
+      PRIVATE ${PYBIND11_INCLUDE_DIR}  # from project CMakeLists.txt
+      PRIVATE ${pybind11_INCLUDE_DIR}  # from pybind11Config
+      PRIVATE ${PYTHON_INCLUDE_DIRS})
+
+    # -fvisibility=hidden is required to allow multiple modules compiled against
+    # different pybind versions to work properly, and for some features (e.g.
+    # py::module_local).  We force it on everything inside the `pybind11`
+    # namespace; also turning it on for a pybind module compilation here avoids
+    # potential warnings or issues from having mixed hidden/non-hidden types.
+    set_target_properties(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden")
+
+    if(WIN32 OR CYGWIN)
+      # Link against the Python shared library on Windows
+      target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
+    endif()
+
+    # Make sure C++11/14 are enabled
+    target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
+  endif()
 
   # The prefix and extension are provided by FindPythonLibsNew.cmake
   set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}")
   set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}")
 
-  # -fvisibility=hidden is required to allow multiple modules compiled against
-  # different pybind versions to work properly, and for some features (e.g.
-  # py::module_local).  We force it on everything inside the `pybind11`
-  # namespace; also turning it on for a pybind module compilation here avoids
-  # potential warnings or issues from having mixed hidden/non-hidden types.
-  set_target_properties(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden")
-
-  if(WIN32 OR CYGWIN)
-    # Link against the Python shared library on Windows
-    target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
-  elseif(APPLE)
+  # NB These properties are not incorporated via `pybind11Config.cmake.in`, so
+  # we will incorporate the flags regardless of using the interface target
+  # library or not.
+  if(APPLE)
     # It's quite common to have multiple copies of the same Python version
     # installed on one's system. E.g.: one copy from the OS and another copy
     # that's statically linked into an application like Blender or Maya.
@@ -172,9 +185,6 @@ function(pybind11_add_module target_name)
     endif()
   endif()
 
-  # Make sure C++11/14 are enabled
-  target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
-
   if(ARG_NO_EXTRAS)
     return()
   endif()