Allow config #defines to be written out to custom config/defines.hpp …

…files

The existing cmake macro can be used to generate #defines for the global
hpx/config/defines.hpp file by using

  hpx_add_config_define(HPX_HAVE_LOGGING)
  hpx_add_config_define(HPX_HAVE_MAX_CPU_COUNT ${HPX_WITH_MAX_CPU_COUNT})
  ...

and then written to hpx/config/defines.hpp using a new macro and
specifying the default namespace

write_config_defines_file(
  TEMPLATE "${PROJECT_SOURCE_DIR}/cmake/templates/config_defines.hpp.in"
  NAMESPACE default
  FILENAME "${CMAKE_BINARY_DIR}/hpx/config/defines.hpp")

This keeps the existing behaviour unchanged.
However a new NAMESPACE feature is supported to allow the user to add

  hpx_add_config_define_namespace(
    DEFINE    HPX_PARCELPORT_VERBS_DEVICE
    VALUE     "\"${HPX_PARCELPORT_VERBS_DEVICE}\""
    NAMESPACE parcelport_verbs)

  hpx_add_config_define_namespace(
    DEFINE    HPX_PARCELPORT_VERBS_INTERFACE
    VALUE     "\"${HPX_PARCELPORT_VERBS_INTERFACE}\""
    NAMESPACE parcelport_verbs)

and then to generate a defines.hpp file as follows

  write_config_defines_file(
    TEMPLATE ""
    NAMESPACE "parcelport_verbs"
    FILENAME "${CMAKE_BINARY_DIR}/hpx/config/parcelport_verbs_defines.hpp")

when no template is specified, the function will generate a copyright
block, and include guard #ifndef...#endif section with the #defines between.
In the above example, the following would be generated from the variables

  #define HPX_PARCELPORT_VERBS_DEVICE "mlx5_0"
  #define HPX_PARCELPORT_VERBS_INTERFACE "ib0"

This feature allows a module (e.g. parcelport) to generate #defines without
writing to the global defines.hpp file and triggering full rebuilds on every change.

CMakeLists.txt

@@ -1654,27 +1654,19 @@ add_plugin_modules()
 ################################################################################
 # Configure the header to include all compile definitions
 ################################################################################
-get_property(HPX_CONFIG_DEFINITIONS_VAR GLOBAL PROPERTY HPX_CONFIG_DEFINITIONS)
-
-list(SORT HPX_CONFIG_DEFINITIONS_VAR)
-list(REMOVE_DUPLICATES HPX_CONFIG_DEFINITIONS_VAR)
-
-set(hpx_config_defines "\n")
-foreach(def ${HPX_CONFIG_DEFINITIONS_VAR})
-  set(hpx_config_defines "${hpx_config_defines}#define ${def} ${${def}_define}\n")#"
-endforeach()
-
 # Generate a defines.hpp to be used in the build directory ...
 set(HPX_DEFINES_PREFIX ${HPX_BUILD_PREFIX})
-configure_file("${PROJECT_SOURCE_DIR}/cmake/templates/config_defines.hpp.in"
-               "${CMAKE_BINARY_DIR}/hpx/config/defines.hpp"
-               @ONLY)
+write_config_defines_file(
+  TEMPLATE "${PROJECT_SOURCE_DIR}/cmake/templates/config_defines.hpp.in"
+  NAMESPACE default
+  FILENAME "${CMAKE_BINARY_DIR}/hpx/config/defines.hpp")
 
 # Generate a defines.hpp to be used in the install directory ...
 set(HPX_DEFINES_PREFIX ${HPX_PREFIX})
-configure_file("${PROJECT_SOURCE_DIR}/cmake/templates/config_defines.hpp.in"
-               "${CMAKE_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/hpx/config/defines.hpp"
-               @ONLY)
+write_config_defines_file(
+  TEMPLATE "${PROJECT_SOURCE_DIR}/cmake/templates/config_defines.hpp.in"
+  NAMESPACE default
+  FILENAME "${CMAKE_BINARY_DIR}/${CMAKE_FILES_DIRECTORY}/hpx/config/defines.hpp")
 
 # Configure hpxrun.py
 configure_file("${PROJECT_SOURCE_DIR}/cmake/templates/hpxrun.py.in"

cmake/HPX_AddDefinitions.cmake

@@ -1,9 +1,14 @@
 # Copyright (c) 2013 Hartmut Kaiser
 # Copyright (c) 2014 Thomas Heller
+# Copyright (c) 2016 John Biddiscombe
 #
 # Distributed under the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
+# ---------------------------------------------------------------------
+# Function to add variables to a list that will be later written out
+# to file hpx/config/defines.hpp
+# ---------------------------------------------------------------------
 # on startup, this is unset, but we'll set it to an empty string anyway
 set_property(GLOBAL PROPERTY HPX_CONFIG_DEFINITIONS "")
 
@@ -15,6 +20,79 @@ function(hpx_add_config_define definition)
     set_property(GLOBAL APPEND PROPERTY HPX_CONFIG_DEFINITIONS "${definition}")
   endif()
 
-  get_property(HPX_CONFIG_DEFINITIONS_VAR GLOBAL PROPERTY HPX_CONFIG_DEFINITIONS)
+endfunction()
+
+# ---------------------------------------------------------------------
+# Function to add config defines to a list that depends on a namespace variable
+# #defines that match the namespace can later be written out to a file  
+# ---------------------------------------------------------------------
+function(hpx_add_config_define_namespace)
+  set(options)
+  set(one_value_args DEFINE NAMESPACE)
+  set(multi_value_args VALUE)
+  cmake_parse_arguments(OPTION 
+    "${options}" "${one_value_args}" "${multi_value_args}" ${ARGN})
+
+  set(DEF_VAR HPX_CONFIG_DEFINITIONS_${OPTION_NAMESPACE})
+
+  # to avoid extra trailing spaces (no value), use an if check
+  if(OPTION_VALUE)       
+    set_property(GLOBAL APPEND PROPERTY ${DEF_VAR} "${OPTION_DEFINE} ${OPTION_VALUE}")
+  else()
+    set_property(GLOBAL APPEND PROPERTY ${DEF_VAR} "${OPTION_DEFINE}")
+  endif()    
+
+endfunction()
+
+# ---------------------------------------------------------------------
+# Function to write variables out from a global var that was set using
+# the config_define functions into a config file
+# ---------------------------------------------------------------------
+function(write_config_defines_file)
+  set(options)
+  set(one_value_args TEMPLATE NAMESPACE FILENAME)
+  set(multi_value_args)
+  cmake_parse_arguments(OPTION 
+    "${options}" "${one_value_args}" "${multi_value_args}" ${ARGN})
 
+  if (${OPTION_NAMESPACE} STREQUAL "default")
+    get_property(DEFINITIONS_VAR GLOBAL PROPERTY 
+      HPX_CONFIG_DEFINITIONS)
+  else()
+    get_property(DEFINITIONS_VAR GLOBAL PROPERTY 
+      HPX_CONFIG_DEFINITIONS_${OPTION_NAMESPACE})
+  endif()
+
+  list(SORT DEFINITIONS_VAR)
+  list(REMOVE_DUPLICATES DEFINITIONS_VAR)
+
+  set(hpx_config_defines "\n")
+  foreach(def ${DEFINITIONS_VAR})
+    set(hpx_config_defines "${hpx_config_defines}#define ${def} ${${def}_define}\n")#"
+  endforeach()
+
+  # if the user has not specified a template, generate a proper header file
+  if (NOT OPTION_TEMPLATE)
+    string(TOUPPER ${OPTION_NAMESPACE} NAMESPACE_UPPER)
+    set(PREAMBLE 
+      "//  Copyright (c) Ste||ar Group\n"
+      "//\n"
+      "//  Distributed under the Boost Software License, Version 1.0. (See accompanying\n"
+      "//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)\n"
+      "\n"
+      "// Do not edit this file! It has been generated by the cmake configuration step.\n"
+      "\n"
+      "#ifndef HPX_CONFIG_${NAMESPACE_UPPER}_HPP\n"      
+      "#define HPX_CONFIG_${NAMESPACE_UPPER}_HPP\n"
+    )      
+    file(WRITE ${OPTION_FILENAME} 
+        ${PREAMBLE}
+        ${hpx_config_defines}
+        "\n#endif\n"
+    )    
+  else()    
+    configure_file("${OPTION_TEMPLATE}"
+                   "${OPTION_FILENAME}"
+                   @ONLY)
+  endif()
 endfunction()