Building OpenCV for IOS fails w/ code signing error

[Chandler]

System information (version)

• OpenCV => 4.1.0
• Operating System / Platform => MacOS 10.14.4
• XCode => 10.2.1
• Compiler => AppleClang 10.0.1.10010046
• Cmake => 3.5.2

Detailed description

Building OpenCV 4.1.0 for IOS fails. The error that sticks out the most is from
build/build-arm64-iphoneos/CMakeFiles/CMakeError.log (attached) and it states:

error: An empty identity is not valid when signing a binary for the product type 'Application'

There is another error in the stdout (attached) that might be related but seems like a red-herring

CMake Error at cmake/OpenCVDetectCXXCompiler.cmake:188 (message):
  OpenCV 4.x requires C++11

It should be noted that the OSX build doesn't not have this issue on my machine, only the IOS one.

Thanks in advance for the help.

Steps to reproduce

cd $CODE/opencv
git checkout tags/4.1.0

mkdir -p $CODE/opencvbuild

python $CODE/opencv/platforms/ios/build_framework.py \
 	--iphoneos_deployment_target 12.2 \
 	--iphoneos_archs arm64 \
	--opencv $CODE/opencv \
	$CODE/opencvbuild

STDOUT

Using IPHONEOS_DEPLOYMENT_TARGET=12.2
Using iPhoneOS ARCHS=['arm64']
Using iPhoneSimulator ARCHS=['i386', 'x86_64']
Executing: ['cmake', '-GXcode', '-DAPPLE_FRAMEWORK=ON', '-DCMAKE_INSTALL_PREFIX=install', '-DCMAKE_BUILD_TYPE=Release', '-DOPENCV_INCLUDE_INSTALL_PATH=include', '-DOPENCV_3P_LIB_INSTALL_PATH=lib/3rdparty', '-DIOS_ARCH=arm64', '-DCMAKE_TOOLCHAIN_FILE=/Users/cbabraham/code/opencv/platforms/ios/cmake/Toolchains/Toolchain-iPhoneOS_Xcode.cmake', '-DCPU_BASELINE=DETECT', '/Users/cbabraham/code/opencv', '-DCMAKE_C_FLAGS=-fembed-bitcode', '-DCMAKE_CXX_FLAGS=-fembed-bitcode'] in /Users/cbabraham/code/opencvbuild/build/build-arm64-iphoneos
Executing: cmake -GXcode -DAPPLE_FRAMEWORK=ON -DCMAKE_INSTALL_PREFIX=install -DCMAKE_BUILD_TYPE=Release -DOPENCV_INCLUDE_INSTALL_PATH=include -DOPENCV_3P_LIB_INSTALL_PATH=lib/3rdparty -DIOS_ARCH=arm64 -DCMAKE_TOOLCHAIN_FILE=/Users/cbabraham/code/opencv/platforms/ios/cmake/Toolchains/Toolchain-iPhoneOS_Xcode.cmake -DCPU_BASELINE=DETECT /Users/cbabraham/code/opencv -DCMAKE_C_FLAGS=-fembed-bitcode -DCMAKE_CXX_FLAGS=-fembed-bitcode
-- Setting up iPhoneOS toolchain for IOS_ARCH='arm64'
-- iPhoneOS toolchain loaded
-- Setting up iPhoneOS toolchain for IOS_ARCH='arm64'
-- iPhoneOS toolchain loaded
-- The CXX compiler identification is AppleClang 10.0.1.10010046
-- The C compiler identification is AppleClang 10.0.1.10010046
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - failed
-- Detecting CXX compile features
-- Detecting CXX compile features - failed
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - failed
-- Detecting C compile features
-- Detecting C compile features - failed
-- Performing Test HAVE_CXX11 (check file: cmake/checks/cxx11.cpp)
-- Performing Test HAVE_CXX11 - Failed
CMake Error at cmake/OpenCVDetectCXXCompiler.cmake:188 (message):
  OpenCV 4.x requires C++11
Call Stack (most recent call first):
  CMakeLists.txt:160 (include)


-- Configuring incomplete, errors occurred!
See also "opencvbuild/build/build-arm64-iphoneos/CMakeFiles/CMakeOutput.log".
See also "opencvbuild/build/build-arm64-iphoneos/CMakeFiles/CMakeError.log".

opencvbuild/build/build-arm64-iphoneos/CMakeFiles/CMakeError.log

Detecting CXX compiler ABI info failed to compile with the following output:
Change Dir: opencvbuild/build/build-arm64-iphoneos/CMakeFiles/CMakeTmp

Run Build Command:"opencvbuild/build/build-arm64-iphoneos/xcodebuild_wrapper" "-project" "CMAKE_TRY_COMPILE.xcodeproj" "build" "-target" "cmTC_f2f02" "-configuration" "Debug"
Build settings from command line:
    ARCHS = arm64
    IPHONEOS_DEPLOYMENT_TARGET = 12.2
    SDKROOT = iphoneos12.2

note: Using new build system
note: Planning build
note: Constructing build description
Build system information
error: An empty identity is not valid when signing a binary for the product type 'Application'. (in target 'cmTC_f2f02')

[Chandler]

related: realm/jazzy#1057

[Chandler]

The code signing error can be addressed w/ a hack by changing

https://github.com/opencv/opencv/blob/master/platforms/ios/cmake/Toolchains/xcodebuild_wrapper.in#L19

to include the arg CODE_SIGNING_ALLOWED=NO

But the build proceeds to another error, which is similar to
#12646

error: Build input file cannot be found: '/Users/cbabraham/code/opencvbuild/build/build-arm64-iphoneos/modules/world/opencl_kernels_ximgproc.cpp'

** BUILD FAILED **
The following build commands failed:
	CompileC /Users/cbabraham/code/opencvbuild/build/build-arm64-iphoneos/modules/world/OpenCV.build/Release-iphoneos/opencv_world.build/Objects-normal/arm64/opencl_kernels_ximgproc.o /Users/cbabraham/code/opencvbuild/build/build-arm64-iphoneos/modules/world/opencl_kernels_ximgproc.cpp normal arm64 c++ com.apple.compilers.llvm.clang.1_0.compiler
(1 failure)

[Chandler]

The 'input file cannot be found' error can be addressed by adding
-UseModernBuildSystem=NO to the list of args found here

opencv/platforms/ios/build_framework.py

Line 177 in f439fc4

buildcmd += [

[Chandler]

FYI after fixing the above two issues, the build proceeded to this error:

Usage: /usr/local/bin/libtool [OPTION]... [MODE-ARG]...
Try 'libtool --help' for more information.
libtool:   error: unrecognised option: '-static'
============================================================
ERROR: Command '['libtool', '-static', '-o', '/Users/cbabraham/code/opencvbuild/build/build-arm64-iphoneos/lib/Release/libopencv_merged.a', ...... 

Which was fixed by this solution that unlinks a homebrew version of libtool
nodejs/node#2341 (comment)

The IOS build of OpenCV then runs to completion 🎉 🎉 🎉

[Bharathsrinivasan]

After fixing this issue
#14374 (comment)
you might encounter the following issue, if you are building with opencv_contrib repository.
opencv/opencv_contrib#1427 (comment)
It can be fixed by the steps mentioned by alalek in that link.

[AlvarHHM]

I encounter another singing error when building version 4.1.1

Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed.
Compiler:  
Build flags: -fembed-bitcode
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdCXX" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')

** BUILD FAILED **



Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed.
Compiler:  
Build flags: 
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdCXX" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')

** BUILD FAILED **



Compiling the C compiler identification source file "CMakeCCompilerId.c" failed.
Compiler:  
Build flags: -fembed-bitcode
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdC" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdC' from project 'CompilerIdC')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdC' from project 'CompilerIdC')

** BUILD FAILED **



Compiling the C compiler identification source file "CMakeCCompilerId.c" failed.
Compiler:  
Build flags: 
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdC" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdC' from project 'CompilerIdC')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdC' from project 'CompilerIdC')

** BUILD FAILED **

[errollgarner]

I have the same error as @AlvarHHM reports. Config is:
OpenCV => 4.2.0
Operating System / Platform => MacOS 10.15.3
XCode => 11.3.1
Compiler => AppleClang 11.0.0
Cmake => 3.10.0

Setting CODE_SIGNING_ALLOWED=NO, as @Chandler suggests doesn't change outcome.

[hudrima1]

Hi,
I can't use the prebuilt iOS framework because it doesn't contain the contribs.
I also gave up with the Toolchainfile from within the OpenCV distribution and also the python
build script. It contains an error in my opinion.

I use this toolchain file: https://github.com/leetal/ios-cmake/blob/master/ios.toolchain.cmake
And I wrote a shell script with direct cmake calls. https://github.com/cpvrlab/SLProject/blob/develop/externals/prebuild_scripts/build_opencv_w_contrib_for_iosV8.sh

You can call it with the OpenCV version tag that you want.
E.g.: ./build_opencv_w_contrib_for_iosV8.sh 4.2.0

It clones OpenCV and OpenCV_Contribs.
Afterwards, it creates the build folder with cmake and starts compiling the modules but ends with an error not finding a source file!
At least it starts compiling.

[suxinde2009]

This issue still exists. I try to build the v4.4.0 iOS framework with the python script, but failed. The error log is as below:

Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed.
Compiler:  
Build flags: -fembed-bitcode
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdCXX" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')

** BUILD FAILED **



Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed.
Compiler:  
Build flags: 
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdCXX" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdCXX' from project 'CompilerIdCXX')

** BUILD FAILED **



Compiling the C compiler identification source file "CMakeCCompilerId.c" failed.
Compiler:  
Build flags: -fembed-bitcode
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdC" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdC' from project 'CompilerIdC')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdC' from project 'CompilerIdC')

** BUILD FAILED **



Compiling the C compiler identification source file "CMakeCCompilerId.c" failed.
Compiler:  
Build flags: 
Id flags:  

The output was:
65
note: Using new build system
note: Planning build
note: Constructing build description
error: Signing for "CompilerIdC" requires a development team. Select a development team in the Signing & Capabilities editor. (in target 'CompilerIdC' from project 'CompilerIdC')
warning: Traditional headermap style is no longer supported; please migrate to using separate headermaps and set 'ALWAYS_SEARCH_USER_PATHS' to NO. (in target 'CompilerIdC' from project 'CompilerIdC')

** BUILD FAILED **