initial code repo

[stor4nfv.git] / src / ceph / cmake / modules / MergeStaticLibraries.cmake

diff --git a/src/ceph/cmake/modules/MergeStaticLibraries.cmake b/src/ceph/cmake/modules/MergeStaticLibraries.cmake
new file mode 100644 (file)
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+++ b/src/ceph/cmake/modules/MergeStaticLibraries.cmake
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+# This function is a helper that will merge static libraries.
+# For example,
+#
+#    merge_static_libraries(mylib staticlibX staticlibY)
+#
+# mylib.a will generate a new static library mylib that is
+# a combination of staticlibX and staticlibY
+#
+function(merge_static_libraries target)
+
+    set(dummy_source ${CMAKE_CURRENT_BINARY_DIR}/${target}_dummy.c)
+    add_library(${target} STATIC ${dummy_source})
+
+    # remove duplicates
+    set(libs ${ARGN})
+    list(REMOVE_DUPLICATES libs)
+
+    # validate that all libs are static
+    foreach(lib ${libs})
+        if (NOT TARGET ${lib})
+            message(FATAL_ERROR "${lib} not a valid target")
+        endif()
+
+        get_target_property(libtype ${lib} TYPE)
+        if(NOT libtype STREQUAL "STATIC_LIBRARY")
+            message(FATAL_ERROR "${lib} not a static library")
+        endif()
+
+        # add a dependency on the lib
+        add_dependencies(${target} ${lib})
+    endforeach()
+
+    # Force the merged Make the generated dummy source file depended on all static input
+    # libs. If input lib changes,the source file is touched
+    # which causes the desired effect (relink).
+    add_custom_command(
+        OUTPUT  ${dummy_source}
+        COMMAND ${CMAKE_COMMAND} -E touch ${dummy_source}
+        DEPENDS ${libs})
+
+    # only LINUX is currently supported. OSX's libtool and windows lib.exe
+    # have native support for merging static libraries, and support for them
+    # can be easily added if required.
+    if(LINUX)
+        # generate a script to merge the static libraries in to the target
+        # library. see https://sourceware.org/binutils/docs/binutils/ar-scripts.html
+        set(mri_script "open $<TARGET_FILE:${target}>=")
+        foreach(lib ${libs})
+            # we use the generator expression TARGET_FILE to get the location
+            # of the library. this will not be expanded until the script file
+            # is written below
+            set(mri_script "${mri_script} addlib $<TARGET_FILE:${lib}>=")
+        endforeach()
+        set(mri_script "${mri_script} save=end")
+
+        add_custom_command(
+            TARGET ${target} POST_BUILD
+            COMMAND echo ${mri_script} | tr = \\\\n | ${CMAKE_AR} -M)
+    endif(LINUX)
+
+    message("-- MergeStaticLibraries: ${target}: merged ${libs}")
+
+    # we want to set the target_link_libraries correctly for the new merged
+    # static library. First we get the list of link libraries for each
+    # of the libs we are merging
+    set(link_libs)
+    foreach(lib ${libs})
+      get_property(trans TARGET ${lib} PROPERTY LINK_LIBRARIES)
+      list(APPEND link_libs ${trans})
+    endforeach()
+
+    if (link_libs)
+        # now remove the duplicates and any of the libraries we already merged
+        list(REMOVE_DUPLICATES link_libs)
+        foreach(lib ${libs})
+            list(REMOVE_ITEM link_libs ${lib})
+        endforeach()
+
+        # set the target link libraries
+        target_link_libraries(${target} ${link_libs})
+
+        message("-- MergeStaticLibraries: ${target}: remaining ${link_libs}")
+    endif()
+
+endfunction()