package/flann: fix build with cmake >= 3.11
PATCH 1/1 package/flann: fix build with cmake >= 3.11
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
--- .../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
package/flann/0001-src-cpp-fix-cmake-3.11-build.patch new file +48 -0
@@ -0,0 +1,48 @@ +From fa5ec96a94646492a3f908e12905b3e48a8e800b Mon Sep 17 00:00:00 2001 +From: Romain Naour <[email protected]> +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 <[email protected]> +--- + 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 +
Signature · 1 line
2.14.3
PATCH 1/1 package/flann: fix build with cmake >= 3.11
Hello Romain,
Quoted 4 lines · Romain Naour
From [1]:
"add_library()andadd_executable()commands can now be called without
any sources and will not complain as long as sources are added later via thetarget_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
Signature · 3 lines
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com
PATCH 1/1 package/flann: fix build with cmake >= 3.11
Hi Thomas,
Le 19/04/2018 ? 22:54, Thomas Petazzoni a ?crit?:
Quoted 9 lines
Hello Romain,
Quoted 4 lines · Romain Naour
From [1]:
"add_library()andadd_executable()commands can now be called without
any sources and will not complain as long as sources are added later via thetarget_sources()command."
Quoted 7 lines
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.
Quoted 3 lines
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.
Quoted 2 lines
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
Quoted 5 lines
Thanks,
Thomas