--- /dev/null
+From eceada586bbf18fc267e437522ec4f1f23ddc656 Mon Sep 17 00:00:00 2001
+From: Samuel Martin <s.martin49@gmail.com>
+Date: Fri, 3 Oct 2014 00:32:40 +0200
+Subject: [PATCH] cmake/OpenCVGenPkgconfig.cmake: rework opencv.pc generation
+
+Using absolute path to locate the components in the "Libs:" field of the
+*.pc can badly break cross-compilation, especially when building
+statically linked objects.
+
+Indeed, pkg-config automatically replaces the '-I...' and '-L...' paths
+when the PKG_CONFIG_SYSROOT_DIR and PKG_CONFIG_LIBDIR environment
+variables are set [1]. This feature is very helpful and common in
+cross-compilation framework like Buildroot [2,3].
+
+When there are absolute paths in the *.pc files, pkg-config won't be
+able to do the path substitions for these paths when the afromentioned
+environment variables are set.
+In such case, since the prefix is the target one, not the sysroot one,
+these libraries' abolute paths will point to:
+- in the best case: a non-existing file (i.e. these files do not exists
+ on the host system;
+- at worst: the host system's libraries. This will make the linking
+ failed because these host system's libraries will most likely not be
+ build for the target architecture [4].
+
+So, this patch replace the components' absolute paths by the form:
+ -L<libdir> -l<libname>
+
+This way, the linker will be able to resolve each dependency path,
+whatever the kind of objects/build (shared object or static build) it
+is dealing with.
+
+Note that for static link, the library order does matter [5]. The order
+of the opencv components has been carefully chosen to comply with this
+requirement.
+
+Fixes #3931
+
+[1] http://linux.die.net/man/1/pkg-config
+[2] http://buildroot.org/
+[3] http://git.buildroot.net/buildroot/tree/package/pkgconf/pkg-config.in
+[4] http://autobuild.buildroot.net/results/e8a/e8a859276db34aff87ef181b0cce98916b0afc90/build-end.log
+[5] http://stackoverflow.com/questions/45135/linker-order-gcc
+
+Signed-off-by: Samuel Martin <s.martin49@gmail.com>
+
+---
+Note: this patch properly applies on top of the master branch, though it
+ has been written on top of the 2.4 branch.
+---
+ cmake/OpenCVGenPkgconfig.cmake | 64 +++++++++++++++++++++++++++---------------
+ 1 file changed, 42 insertions(+), 22 deletions(-)
+
+diff --git a/cmake/OpenCVGenPkgconfig.cmake b/cmake/OpenCVGenPkgconfig.cmake
+index fa57db9..183c56d 100644
+--- a/cmake/OpenCVGenPkgconfig.cmake
++++ b/cmake/OpenCVGenPkgconfig.cmake
+@@ -8,10 +8,6 @@
+ #
+ # ${BIN_DIR}/unix-install/opencv.pc -> For use *with* "make install"
+ # -------------------------------------------------------------------------------------------
+-set(prefix "${CMAKE_INSTALL_PREFIX}")
+-set(exec_prefix "\${prefix}")
+-set(libdir "") #TODO: need link paths for OpenCV_EXTRA_COMPONENTS
+-set(includedir "\${prefix}/${OPENCV_INCLUDE_INSTALL_PATH}")
+
+ if(CMAKE_BUILD_TYPE MATCHES "Release")
+ set(ocv_optkind OPT)
+@@ -35,42 +31,66 @@ ocv_list_reverse(OpenCV_LIB_COMPONENTS)
+ ocv_list_reverse(OpenCV_EXTRA_COMPONENTS)
+
+ #build the list of components
+-set(OpenCV_LIB_COMPONENTS_ "")
+-foreach(CVLib ${OpenCV_LIB_COMPONENTS})
+- get_target_property(libpath ${CVLib} LOCATION_${CMAKE_BUILD_TYPE})
+- get_filename_component(libname "${libpath}" NAME)
+
+- if(INSTALL_TO_MANGLED_PATHS)
+- set(libname "${libname}.${OPENCV_VERSION}")
+- endif()
++# Note:
++# when linking against static libraries, if libfoo depends on libbar, then
++# libfoo must come first in the linker flags.
++
++# world is a special target whose library should come first, especially for
++# static link.
++if(OpenCV_LIB_COMPONENTS MATCHES "opencv_world")
++ list(REMOVE_ITEM OpenCV_LIB_COMPONENTS "opencv_world")
++ list(INSERT OpenCV_LIB_COMPONENTS 0 "opencv_world")
++endif()
++
++set(OpenCV_LIB_COMPONENTS_)
++foreach(CVLib ${OpenCV_LIB_COMPONENTS})
+
+- #need better solution....
+- if(libpath MATCHES "3rdparty")
+- set(installDir "share/OpenCV/3rdparty/${OPENCV_LIB_INSTALL_PATH}")
++ get_target_property(libloc ${CVLib} LOCATION_${CMAKE_BUILD_TYPE})
++ if(libloc MATCHES "3rdparty")
++ set(libpath "\${exec_prefix}/share/OpenCV/3rdparty/${OPENCV_LIB_INSTALL_PATH}")
+ else()
+- set(installDir "${OPENCV_LIB_INSTALL_PATH}")
++ set(libpath "\${exec_prefix}/${OPENCV_LIB_INSTALL_PATH}")
+ endif()
++ list(APPEND OpenCV_LIB_COMPONENTS_ "-L${libpath}")
++
++ get_filename_component(libname ${CVLib} NAME_WE)
++ string(REGEX REPLACE "^lib" "" libname "${libname}")
++ list(APPEND OpenCV_LIB_COMPONENTS_ "-l${libname}")
+
+- set(OpenCV_LIB_COMPONENTS_ "${OpenCV_LIB_COMPONENTS_} \${exec_prefix}/${installDir}/${libname}")
+ endforeach()
+
+ # add extra dependencies required for OpenCV
+-set(OpenCV_LIB_COMPONENTS ${OpenCV_LIB_COMPONENTS_})
+ if(OpenCV_EXTRA_COMPONENTS)
+ foreach(extra_component ${OpenCV_EXTRA_COMPONENTS})
+
+- if(extra_component MATCHES "^-[lL]" OR extra_component MATCHES "[\\/]")
+- set(maybe_l_prefix "")
++ if(extra_component MATCHES "^-[lL]")
++ set(libprefix "")
++ set(libname "${extra_component}")
++ elseif(extra_component MATCHES "[\\/]")
++ get_filename_component(libdir "${extra_component}" PATH)
++ list(APPEND OpenCV_LIB_COMPONENTS_ "-L${libdir}")
++ get_filename_component(libname "${extra_component}" NAME_WE)
++ string(REGEX REPLACE "^lib" "" libname "${libname}")
++ set(libprefix "-l")
+ else()
+- set(maybe_l_prefix "-l")
++ set(libprefix "-l")
++ set(libname "${extra_component}")
+ endif()
+-
+- set(OpenCV_LIB_COMPONENTS "${OpenCV_LIB_COMPONENTS} ${maybe_l_prefix}${extra_component}")
++ list(APPEND OpenCV_LIB_COMPONENTS_ "${libprefix}${libname}")
+
+ endforeach()
+ endif()
+
++list(REMOVE_DUPLICATES OpenCV_LIB_COMPONENTS_)
++string(REPLACE ";" " " OpenCV_LIB_COMPONENTS "${OpenCV_LIB_COMPONENTS_}")
++
+ #generate the .pc file
++set(prefix "${CMAKE_INSTALL_PREFIX}")
++set(exec_prefix "\${prefix}")
++set(libdir "\${exec_prefix}/${OPENCV_LIB_INSTALL_PATH}")
++set(includedir "\${prefix}/${OPENCV_INCLUDE_INSTALL_PATH}")
++
+ if(INSTALL_TO_MANGLED_PATHS)
+ set(OPENCV_PC_FILE_NAME "opencv-${OPENCV_VERSION}.pc")
+ else()
+--
+2.4.1
+
projects / buildroot.git / commitdiff