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Will cmake compiled TFLite work on android?

I'm making a project with 2 variations, a desktop version and an android version. Both of them are using the same c++ code base. I want to use TFLite without getting into any android configuration like gradle or an aar file. I just want a pure .so file that my c++ can use thus android can through ndk. I know there are some complications like ndk using clang and requiring arm64 architecture, but I think it should be possible. Note that my project requires ndk version 22 and above.
Here is how I configured tflite for my desktop/debian project:
On ~/Desktop/ I ran git clone https://github.com/tensorflow/tensorflow.git tensorflow_src
mkdir tflite_build & cd ~/Desktop/tflite_build
cmake ../tensorflow_src/tensorflow/lite
cmake --build . I've removed the -J flag regardless of what the docs says because it causes my pc to freeze.
mkdir ~/Desktop/tf_test & cd ~/Desktop/tf_test
Create a CMakeLists.txt and a main.cpp file inside tf_testdirectory.
Put the main code from the minimal example on the github repo provided above then this code in CMake:
cmake_minimum_required(VERSION 3.16)
project(minimal C CXX)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DTFLITE_DISABLE_TELEMETRY=1")
set(TENSORFLOW_SOURCE_DIR "" CACHE PATH
"Directory that contains the TensorFlow project" )
if(NOT TENSORFLOW_SOURCE_DIR)
get_filename_component(TENSORFLOW_SOURCE_DIR
"/home/user/Desktop/tensorflow_src" ABSOLUTE)
endif()
add_subdirectory(
"${TENSORFLOW_SOURCE_DIR}/tensorflow/lite"
"${CMAKE_CURRENT_BINARY_DIR}/tensorflow-lite" EXCLUDE_FROM_ALL)
add_executable(minimal minimal.cc)
target_link_libraries(minimal tensorflow-lite)
Created the folder tf_Test/build and ran cmake .. inside it.
After cmake is completed I run make inside the build directory
This works just fine on debian. However when I try to add this to my cmake on my android ndk project, connect my tablet and run the project I get all these errors:
...
- Looking for strtoull_l - found
-- Using toolchain file: /home/user/Android/Sdk/ndk/25.0.8775105/build/cmake/android.toolchain.cmake.
-- CMAKE_CXX_FLAGS: -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -frtti -fexceptions -fvisibility=hidden -std=c++17 -O0 -Wall -Wextra -Wshadow -Wnon-virtual-dtor -pthread -frtti -fexceptions
-- Found Python3: /usr/bin/python3.9 (found suitable version "3.9.2", minimum required is "3.5") found components: Interpreter
-- Downloading pthreadpool to /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/pthreadpool-source (define PTHREADPOOL_SOURCE_DIR to avoid it)
-- Configuring incomplete, errors occurred!
See also "/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/pthreadpool-download/CMakeFiles/CMakeOutput.log".
-- The ASM compiler identification is Clang with GNU-like command-line
-- Found assembler: /home/user/Android/Sdk/ndk/25.0.8775105/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
-- Downloading FP16 to /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/FP16-source (define FP16_SOURCE_DIR to avoid it)
-- Configuring incomplete, errors occurred!
See also "/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/FP16-download/CMakeFiles/CMakeOutput.log".
-- Downloading FXdiv to /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/FXdiv-source (define FXDIV_SOURCE_DIR to avoid it)
-- Configuring incomplete, errors occurred!
See also "/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/FXdiv-download/CMakeFiles/CMakeOutput.log".
-- RUY is enabled.
-- Configuring incomplete, errors occurred!
See also "/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/CMakeFiles/CMakeOutput.log".
See also "/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/CMakeFiles/CMakeError.log".
CMake Warning at /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/abseil-cpp/CMakeLists.txt:70 (message):
A future Abseil release will default ABSL_PROPAGATE_CXX_STD to ON for CMake
3.8 and up. We recommend enabling this option to ensure your project still
builds correctly.
CMake Error: CMake was unable to find a build program corresponding to "Ninja". CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
No such file or directory
CMake Error: Generator: execution of make failed. Make command was: &&
CMake Error at /home/user/Desktop/official_stuff/tensorflow_src/tensorflow/lite/CMakeLists.txt:167 (add_subdirectory):
add_subdirectory given source
"/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/pthreadpool-source"
which is not an existing directory.
CMake Error: CMake was unable to find a build program corresponding to "Ninja". CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
No such file or directory
CMake Error: Generator: execution of make failed. Make command was: &&
CMake Error: CMake was unable to find a build program corresponding to "Ninja". CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
No such file or directory
CMake Error: Generator: execution of make failed. Make command was: &&
CMake Error at /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/xnnpack/CMakeLists.txt:844 (ADD_SUBDIRECTORY):
ADD_SUBDIRECTORY given source
"/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/pthreadpool-source"
which is not an existing directory.
CMake Error at /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/xnnpack/CMakeLists.txt:884 (ADD_SUBDIRECTORY):
ADD_SUBDIRECTORY given source
"/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/FXdiv-source"
which is not an existing directory.
CMake Error at /home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/xnnpack/CMakeLists.txt:908 (ADD_SUBDIRECTORY):
ADD_SUBDIRECTORY given source
"/home/user/Desktop/native/examples/android/app/.cxx/Debug/5c1w1z3w/arm64-v8a/FP16-source"
which is not an existing directory.
What's the right way to approach this? Following the android build documentation on tflite's website causes a lot of problems.
Update:
Installing ninja fixed almost all my problems, the only error I have now is:
In file included from /home/user/Desktop/official_stuff/tensorflow_src/tensorflow/lite/python/interpreter_wrapper/python_error_reporter.cc:16:
/home/user/Desktop/official_stuff/tensorflow_src/tensorflow/lite/python/interpreter_wrapper/python_error_reporter.h:19:10: fatal error: 'Python.h' file not found
python3 is in fact installed on my system, I used it on a c code before.
Update: Adding this to top of my cmake solved the python issue:
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -I/usr/include/python3.9 -I/usr/include/python3.9 -Wno-unused-result -Wsign-compare -g -ffile-prefix-map=/build/python3.9-RNBry6/python3.9-3.9.2=. -specs=/usr/share/dpkg/no-pie-compile.specs -fstack-protector -Wformat -Werror=format-security -DNDEBUG -g -fwrapv -Wall")
Update:
Now I get:
In file included from /home/user/Desktop/SmartAlpha/official_stuff/tensorflow_src/tensorflow/lite/python/interpreter_wrapper/numpy.cc:17:
In file included from /home/user/Desktop/SmartAlpha/official_stuff/tensorflow_src/tensorflow/lite/python/interpreter_wrapper/numpy.h:49:
In file included from /usr/include/python3.9/Python.h:8:
/usr/include/python3.9/pyconfig.h:9:12: fatal error: 'aarch64-linux-gnu/python3.9/pyconfig.h' file not found

LAST EDIT: You seem to completely overlook what I'm trying to explain you the whole time about different architectures. Your phone is not running on the same cpu architecture as your desktop. Your desktop machine is most likely running on amd64, while your phone is most likely arm64 which is also known as Aarch64 (do you now see what the latest error means? - It can't find the appropriate packages for the correct architecture - you can see that from the path in the error message).
You installed the amd64 package by issuing sudo apt-get install python-dev not the arm64 package. Check this official debian wiki on how to use MultiArch packages
You need to:
Update your system so that it can download the packages for different architectures
And sudo apt-get install python-dev:arm64
EDIT: Regarding the error in the updated question, you are most likely missing python development packages. Since you are on Debian I've looked for a possible package of interested and this might be it:
python-dev, try to apt-get it for the correct architecture that you need and maybe it will resolve your issues.
Make sure that Ninja is installed. CMake is trying to use it - this confuses a lot of users as they most commonly use Makefiles and don't know that an alternative exists. I don't see you explicitly stating that you use CMake + Ninja and hence I mention it.
If you have Ninja installed then the issue is most likely caused by the fact that it can't resolve the path via just the executable name. Take a look at CMAKE_MAKE_PROGRAM to better understand what I mean.
If 2. is your issue then you can try and set the whole path to this CMAKE_MAKE_PROGRAM variable, i.e. set(CMAKE_MAKE_PROGRAM /absolute/path/to/bin/ninja) and see if resolves the issue.

Android NDK clang compiler error showing 'No such file or directory' on Windows

I am trying to learn how to use c/c++ native code with android using ndk r21. I linked my C++ cmake file into my android project and the cpp shared libraries files where generated. However, I am getting a compiler error as follows:-
C/C++ Configuration Problem
Toka | debug | x86
Compiler exited with error code 1: C:\Users\ASUS\AppData\Local\Android\Sdk\ndk\21.0.6113669\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe -xc++ --target=i686-none-linux-android16 --gcc-toolchain=C:/Users/ASUS/AppData/Local/Android/Sdk/ndk/21.0.6113669/toolchains/llvm/prebuilt/windows-x86_64 --sysroot=C:/Users/ASUS/AppData/Local/Android/Sdk/ndk/21.0.6113669/toolchains/llvm/prebuilt/windows-x86_64/sysroot -DTOKA_ARCHIVE_DIR=\"../docs/\" -DTOKA_BASE_DIR=\"../\" -DTOKA_DATABASE_DIR=\"../docs/database/\" -DTOKA_DEVELOPMENT_BUILD -DTOKA_PLUGIN_DIR=\"plugins/Debug/\" -DTOKA_SOURCE -DToka_EXPORTS -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -mstackrealign -D_FORTIFY_SOURCE=2 -Wformat -fexceptions -frtti /W3 -O0 -fno-limit-debug-info -fPIC -c -fpch-preprocess -v -dD -E
Android (5900059 based on r365631c) clang version 9.0.8 (https://android.googlesource.com/toolchain/llvm-project 207d7abc...
This is the part of the error that I can copy to the clipboard. The full error on one of the libraries is in the image below.
Error Message(Cannot Copy it to the clip board)
I tried searching google for similar errors and found none. Some people said it maybe path length problem on windows. I copied my ndk directly under C:\ to get the shortest path possible but to no avail. I followed the guide on configuring cmake and ndk for android studio here but still got the same error. I installed a later version of cmake I later learnt was useless as ndk comes with it own cmake installation. I installed older ndk r20 and r12b and the problem still did not go away. Infact, it seemed r12b did not support cmake. I do not know what to do anymore. I have been trying to solve this for 3 days. it seems this problem has an obvious solution that I am overlooking. Can someone please help me. Thanks.

For me it was a space character problem. Project folder (or project name) should not contain any white space character. Obviously some internal command line does not support while space, or some double quotes are missing.

difference between prebuild tool-chain and custom tool-chain compilers in android NDK

so I'm trying to figure out how to build ICU for android. Initially I tryed to make it with standalone tool-chain, and after some battles I was able to do that at least for x86_64 arch (didn't try with others). However I don't want to have fully custom build system so I decide to figure out how to make it with prebuild toolchains. And I found that it's behave very different - which is very strange. So this was my command when I actually try to configure ICU with standalone tool-chain:
icu/source/configure --disable-shared --enable-static --disable-dyload
--disable-extras --disable-tests --disable-samples --prefix=/icu/build --host=x86_64-linux-android --with-cross-build=/toplay/icu/icu_linux CC=/custom_toolchain/bin/clang
CXX=/custom_toolchain/bin/clang++
LD=/custom_toolchain/bin/x86_64-linux-android-ld
AR=/custom_toolchain/bin/x86_64-linux-android-ar
CFLAGS="-fPIC -DANDROID -fdata-sections -ffunction-sections"
CXXFLAGS="-fPIC -DANDROID -frtti -fno-exceptions -fdata-sections
-ffunction-sections"
So, having all the same command, but only changing compilers and tools from prebuild toolchain which will look like:
icu/source/configure --disable-shared --enable-static --disable-dyload
--disable-extras --disable-tests --disable-samples --prefix=/icu/build --host=x86_64-linux-android --with-cross-build=/toplay/icu/icu_linux CC=/ndk-bundle/toolchains/x86_64-4.9/prebuilt/linux-x86_64/bin/clang
CXX=/ndk-bundle/toolchains/x86_64-4.9/prebuilt/linux-x86_64/bin/clang++
LD=/ndk-bundle/toolchains/x86_64-4.9/prebuilt/linux-x86_64/bin/x86_64-linux-android-ld
AR=/ndk-bundle/toolchains/x86_64-4.9/prebuilt/linux-x86_64//bin/x86_64-linux-android-ar
CFLAGS="-fPIC -DANDROID -fdata-sections -ffunction-sections"
CXXFLAGS="-fPIC -DANDROID -frtti -fno-exceptions -fdata-sections
-ffunction-sections"
I get very different configure step results. Which I placed there: (TLDR: main diff: in prebuild tool-chain case system can't understand that it's cross-compile mode, it's find nl_langinfo, strtod_l which isn't available in android) And if standalone tool-chain initially could build ICU, in prebuild case build process eventually broke.
So my question: what is the difference between compilers and tools in prebuild and standalone case and what flags/settings I need to add to make it work in prebuild case?

This is the expected behavior. I've answered this on our bugtracker.
Our Clang defaults to targeting x86 Linux, not any flavor of Android. Setting up your target flags is one of the many things standalone toolchains do.
I'm not really sure what problem you're trying to solve. Whatever you get working with autoconf is going to essentially be a cobbled together standalone toolchain. Standalone toolchains exist entirely for dealing with this kind of scenario.
To answer your specific question here:
what is the difference between compilers and tools in prebuild and standalone case and what flags/settings I need to add to make it work in prebuild case?
Standalone toolchains are the prebuilt toolchains with a different directory layout (so the compilers can infer the locations of binutils, the sysroot, and the STL) and a few default flags (like -target for Clang). If you were to get this working, you'd have just reinvented this wheel (possibly by using -gcc-toolchain and a bunch of --sysroot, -isystem, -L stuff rather than changing the directory structure.
In case "why doesn't this work out of the box?" is a follow up question, remember that in Android you have many architectures, even more target versions of the OS, and a handful of STLs to choose from. Neither Clang nor GCC can currently be set up in a way that it can deal with all of Android's variations (long term I do expect to change that, but that's quite a ways down the road).

Building native library with standalone toolchain android arm

I am trying to build libraw as a Android shared library. It looks the lib is too complex to use with Android.mk etc, or better: I am not capable yet of doing that.
I tried the route of using a standalone toolchain from the NDK, but I am getting stuck when compiling this lib.
This is the path I take to compile the lib. Please point out if I am making obvious errors:
I downloaded the ndk.
ran: make-standalone-toolchain.sh
Added the bin folder of that standalone toolchain as first item in my PATH.
Ran ./configure with --host=arm-linux-androideabi. This succeeded
Ran make, here it crashed very fast.
LibRaw-0.14.4$ make
depbase=`echo internal/dcraw_common.lo | sed 's|[^/]*$|.deps/&|;s|\.lo$||'`;\
/bin/bash ./libtool --tag=CXX --mode=compile arm-linux-androideabi-g++ -DPACKAGE_NAME=\"LibRaw\" -DPACKAGE_TARNAME=\"libraw\" -DPACKAGE_VERSION=\"0.14.4\" -DPACKAGE_STRING=\"LibRaw\ 0.14.4\" -DPACKAGE_BUGREPORT=\"info#libraw.org\" -DPACKAGE_URL=\"http://www.libraw.org\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -I. -I/usr/local/include -g -O2 -MT internal/dcraw_common.lo -MD -MP -MF $depbase.Tpo -c -o internal/dcraw_common.lo internal/dcraw_common.cpp &&\
mv -f $depbase.Tpo $depbase.Plo
libtool: compile: arm-linux-androideabi-g++ -DPACKAGE_NAME=\"LibRaw\" -DPACKAGE_TARNAME=\"libraw\" -DPACKAGE_VERSION=\"0.14.4\" "-DPACKAGE_STRING=\"LibRaw 0.14.4\"" -DPACKAGE_BUGREPORT=\"info#libraw.org\" -DPACKAGE_URL=\"http://www.libraw.org\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -I. -I/usr/local/include -g -O2 -MT internal/dcraw_common.lo -MD -MP -MF internal/.deps/dcraw_common.Tpo -c internal/dcraw_common.cpp -fPIC -DPIC -o internal/.libs/dcraw_common.o
internal/dcraw_common.cpp: In member function 'void LibRaw::read_shorts(ushort*, int)':
internal/dcraw_common.cpp:119: error: 'swab' was not declared in this scope
internal/dcraw_common.cpp: In member function 'void LibRaw::write_ppm_tiff()':
internal/dcraw_common.cpp:9235: error: 'swab' was not declared in this scope
make: *** [internal/dcraw_common.lo] Error 1
I doubt this error message is helpfull here at stackoverflow, but I am left wondering if I should have applied some additional flags or configuration to get this to work?
Note that I am able to compile this lib succesfully if just compiling for my system without crosscompiling. (linux 32bit).
When I am looking to a instruction for building GDAL for Android (here), it uses a additional setting of LIBS="-lsupc++ -lstdc++". This links the STL and C++ exceptions?
However, when I set those before running my configure I get immediately errors like:
configure:3018: checking whether the C++ compiler works
configure:3040: arm-linux-androideabi-g++ conftest.cpp -lsupc++ -lstdc++ >&5
/tmp/android-chain/bin/../lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-androideabi/bin/ld: cannot find -lsupc++
collect2: ld returned 1 exit status
So, I am a bit stuck. Someone an idea?

I had to add an implementation of the swab function, since the NDK does not have that one.
Afterwards this compiled fine (but I used the crystax ndk).
A better way toolwise was to just use a Android.mk file and use ndk-build to compile it.

Linker error from the bottom of your question occurs because make-standalone-toolchain.sh from NDK r7 creates incomplete toolchain (it misses some libraries including libsupc++.a). I recommend you try making a toolchain from one of previous NDK releases (r6b should be fine).

migrating a linux driver to Android

I'm porting a 3G modem written for Linux for laptops to an embedded android (Gingerbread) device with an ARM processor. I already got the device driver compiled (C code) as a module (.ko file) and installed. I see it when I boot the kernel and it runs well. It hooks up to the USB port as intended. It's happy ready to be talked to.
The next required piece is the "connection manager" written in C++. This is where I have a problem. This doesn't run in Kernel space but it is not a regular Android application with a user interface. This is a "task" running in background that should be started from the "init.rc" file at boot time. The makefile provided with the source code is good to set the dependencies but it is useless as far as the platform I want to target. I'm using the toolchain provided with the Android source code "arm-eabi-*" (runs off of a Ubuntu machine) that I used to compile Android and the kernel. I got lots of compile errors primary because it uses the standard "libc" libraries which doesn't exist in Android. I replaced it by the "bionic libc" which is a light weight subset version of linux libc for android. On top of it, it looks for "crt0.o" which is the start-up code a statically linked program in a linux environment(and several other OS). In Android it is dynamically linked at run time, therefor uses something else than crt0.o.
There is tons of information on Android app programming on the web but, very little on that kind of low level stuff. If anybody has a working makefile for building that kind of C++ code to run as a background task under Android ARM, I would very appreciate to have a look at it or if there is any information that could help me find a way to do that. Or if anyone has done something like that could give me some clues on how to achieve this.

Almost a year later, but here is a makefile that will compile a simple native app:
NDK_USR_PATH := $(NDK_USR)
C_FILES := $(wildcard *.c) $(wildcard *.cpp)
O_FILES := $(patsubst %.cpp,%.o,$(C_FILES))
O_FILES := $(patsubst %.c,%.o,$(C_FILES))
out: $(O_FILES)
#arm-eabi-gcc -o $# $< -Bdynamic -Wl,--gc-section -Wl,-z,nocopyreloc -Wl,--no-undefined -Wl,--dynamic-linker=/system/bin/linker -Wl,-rpath-link=$(NDK_USR_PATH)/lib -nostdlib $(NDK_USR_PATH)/lib/crtend_android.o $(NDK_USR_PATH)/lib/crtbegin_dynamic.o -L$(NDK_USR_PATH)/lib -lc
%.o: %.c
#arm-eabi-gcc -o $# $< -c -I$(NDK_USR_PATH)/include -fno-short-enums
clean:
#rm -f *.o
#rm -f out
It compiles any .c files in the same directory into an app named "out". It requires the environment variable NDK_USR to point to the ndk directory "ndk/android-ndk-r7/platforms/android-14/arch-arm/usr/".
This should dynamically link to the bionic libc, and should enable android driver development.
Be careful when copying and pasting the above makefile. Make is very specific about tab characters.