| Message ID | 20180418191912.25410-1-romain.naour@gmail.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | package/flann: fix build with cmake >= 3.11 | expand |
Hello Romain, On Wed, 18 Apr 2018 21:19:12 +0200, Romain Naour wrote: > From [1]: > "add_library() and add_executable() commands can now be called without > any sources and will not complain as long as sources are added later > via the target_sources() command." I must be misunderstanding something then. The code currently is: add_library(flann_cpp SHARED "") So it has no source code, and this works fine with CMake < 3.11. And you're saying that it's only in CMake >= 3.11 that having no source code is valid. And you fix that by adding a dummy source code file. I'm totally confused here. Also, why do they build a library with nothing inside ? Does it make sense ? Thanks, Thomas
Hi Thomas, Le 19/04/2018 à 22:54, Thomas Petazzoni a écrit : > Hello Romain, > > On Wed, 18 Apr 2018 21:19:12 +0200, Romain Naour wrote: > >> From [1]: >> "add_library() and add_executable() commands can now be called without >> any sources and will not complain as long as sources are added later >> via the target_sources() command." > > I must be misunderstanding something then. The code currently is: > > add_library(flann_cpp SHARED "") > > So it has no source code, and this works fine with CMake < 3.11. And > you're saying that it's only in CMake >= 3.11 that having no source > code is valid. Well, it seems a bug in CMake < 3.11. > > And you fix that by adding a dummy source code file. I'm totally > confused here. So do I. I don't understand how it can work with older CMake. > Also, why do they build a library with nothing inside ? Does it make > sense ? The library is created by linking with the flann_cpp_s static library with this line: target_link_libraries(flann_cpp -Wl,-whole-archive flann_cpp_s -Wl,-no-whole-archive) If you try to use "add_library(flann_cpp SHARED ${CPP_SOURCES})" (as it should be normally done), the link fail due to already defined symbol. They are building the shared version using the static library "to speedup the build time": https://github.com/mariusmuja/flann/commit/0fd62b43be2fbb0b8d791ee36290791224dc030c Alpinelinux removed/commented retentively this part of the CMake code: https://github.com/alpinelinux/aports/commit/fe5137a340af202cefe6b67601af0133b6b660bd Best regards, Romain > > Thanks, > > Thomas >
diff --git a/package/flann/0001-src-cpp-fix-cmake-3.11-build.patch b/package/flann/0001-src-cpp-fix-cmake-3.11-build.patch new file mode 100644 index 0000000000..5542c3cfc8 --- /dev/null +++ b/package/flann/0001-src-cpp-fix-cmake-3.11-build.patch @@ -0,0 +1,48 @@ +From fa5ec96a94646492a3f908e12905b3e48a8e800b Mon Sep 17 00:00:00 2001 +From: Romain Naour <romain.naour@gmail.com> +Date: Wed, 18 Apr 2018 20:24:13 +0200 +Subject: [PATCH] src/cpp: fix cmake >= 3.11 build + +Upstream status: Pending + +https://github.com/mariusmuja/flann/issues/369 + +Signed-off-by: Romain Naour <romain.naour@gmail.com> +--- + src/cpp/CMakeLists.txt | 4 ++-- + src/cpp/empty.cpp | 1 + + 2 files changed, 3 insertions(+), 2 deletions(-) + create mode 100644 src/cpp/empty.cpp + +diff --git a/src/cpp/CMakeLists.txt b/src/cpp/CMakeLists.txt +index b44a735..a816863 100644 +--- a/src/cpp/CMakeLists.txt ++++ b/src/cpp/CMakeLists.txt +@@ -29,7 +29,7 @@ if (BUILD_CUDA_LIB) + endif() + + if(CMAKE_SYSTEM_NAME STREQUAL "Linux" AND CMAKE_COMPILER_IS_GNUCC) +- add_library(flann_cpp SHARED "") ++ add_library(flann_cpp SHARED "empty.cpp") + set_target_properties(flann_cpp PROPERTIES LINKER_LANGUAGE CXX) + target_link_libraries(flann_cpp -Wl,-whole-archive flann_cpp_s -Wl,-no-whole-archive) + +@@ -85,7 +85,7 @@ if (BUILD_C_BINDINGS) + set_property(TARGET flann_s PROPERTY COMPILE_DEFINITIONS FLANN_STATIC) + + if(CMAKE_SYSTEM_NAME STREQUAL "Linux" AND CMAKE_COMPILER_IS_GNUCC) +- add_library(flann SHARED "") ++ add_library(flann SHARED "empty.cpp") + set_target_properties(flann PROPERTIES LINKER_LANGUAGE CXX) + target_link_libraries(flann -Wl,-whole-archive flann_s -Wl,-no-whole-archive) + else() +diff --git a/src/cpp/empty.cpp b/src/cpp/empty.cpp +new file mode 100644 +index 0000000..40a8c17 +--- /dev/null ++++ b/src/cpp/empty.cpp +@@ -0,0 +1 @@ ++/* empty */ +-- +2.14.3 +
CMake 3.11 changed the behaviour of add_library() that break the existing flann CMake code. From [1]: "add_library() and add_executable() commands can now be called without any sources and will not complain as long as sources are added later via the target_sources() command." This issue is already reported upstream [2] with a proposed solution. Fixes: http://autobuild.buildroot.net/results/b2f/b2febfaf8c44ce477b3e4a5b9b976fd25e8d7454 [1] https://cmake.org/cmake/help/v3.11/release/3.11.html [2] https://github.com/mariusmuja/flann/issues/369 Signed-off-by: Romain Naour <romain.naour@gmail.com> Cc: Davide Viti <zinosat@tiscali.it> Cc: Bernd Kuhls <bernd.kuhls@t-online.de> --- .../flann/0001-src-cpp-fix-cmake-3.11-build.patch | 48 ++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 package/flann/0001-src-cpp-fix-cmake-3.11-build.patch