can not compile bulletphysics as static library with CMAKE for android-ndk C++ project

Question

I trying to compile bulletphysics as static library with CMAKE for Android NDK (Android studio + Clang compiler) Here is main CMakeLists.txt:

cmake_minimum_required(VERSION 3.10)

set(BULLET_VERSION "3.17")

add_definitions(-DUSE_PTHREADS -DSCE_PFX_USE_SIMD_VECTORMATH)
add_compile_options(-pthread)

add_subdirectory(LinearMath)
add_subdirectory(Bullet3Common)
add_subdirectory(BulletCollision)
add_subdirectory(BulletDynamics)
add_subdirectory(BulletSoftBody)
add_subdirectory(BulletInverseDynamics)

add_library(bullet-static STATIC DoNothing.cpp) # DoNothing.cpp for help compiler recognize language. Contains 1 empty method
target_link_libraries(bullet-static LinearMath-static Bullet3Common-static BulletCollision-static BulletDynamics-static BulletSoftBody-static BulletInverseDynamics-static)

Next iam linking this bullet-static lib to other static lib named engine-static and next link engine-static lib to shared lib main:
bullet-static(static) -> engine-static(static) -> main(shared)

After compilation i have error:

FAILED: D:/Programmy/Android/android-project/app/build/intermediates/cmake/debug/obj/arm64-v8a/libmain.so 
cmd.exe /C "cd . && C:\Users\v\AppData\Local\Android\Sdk\ndk\21.1.6352462\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe --target=aarch64-none-linux-android23 --gcc-toolchain=C:/Users/v/AppData/Local/Android/Sdk/ndk/21.1.6352462/toolchains/llvm/prebuilt/windows-x86_64 --sysroot=C:/Users/v/AppData/Local/Android/Sdk/ndk/21.1.6352462/toolchains/llvm/prebuilt/windows-x86_64/sysroot -fPIC -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security   -O0 -fno-limit-debug-info  -Wl,--exclude-libs,libgcc.a -Wl,--exclude-libs,libgcc_real.a -Wl,--exclude-libs,libatomic.a -static-libstdc++ -Wl,--build-id -Wl,--fatal-warnings -Wl,--no-undefined -Qunused-arguments -shared -Wl,-soname,libmain.so -o D:\Programmy\Android\android-project\app\build\intermediates\cmake\debug\obj\arm64-v8a\libmain.so src/CMakeFiles/main.dir/main.cpp.o src/CMakeFiles/main.dir/GUILayer.cpp.o src/CMakeFiles/main.dir/SceneLayer.cpp.o  Beryll_engine/libBeryll-static.a -lGLESv3 Beryll_engine/libs/SDL2/libSDL2.a -lm -ldl -llog -landroid D:/Programmy/Android/android-project/app/build/intermediates/cmake/debug/obj/arm64-v8a/libhidapi.so -llog -lGLESv1_CM -lGLESv2 -Wl,--no-undefined Beryll_engine/libs/SDL2_image/libSDL2_image-static.a Beryll_engine/libs/SDL2_image/jpeg/libjpeg-static.a Beryll_engine/libs/SDL2_image/png/libpng16.a C:/Users/v/AppData/Local/Android/Sdk/ndk/21.1.6352462/toolchains/llvm/prebuilt/windows-x86_64/sysroot/usr/lib/aarch64-linux-android/libz.a C:/Users/v/AppData/Local/Android/Sdk/ndk/21.1.6352462/toolchains/llvm/prebuilt/windows-x86_64/sysroot/usr/lib/aarch64-linux-android/libm.a Beryll_engine/libs/SDL2_mixer/libSDL2_mixer-static.a Beryll_engine/libs/SDL2_mixer/mp3/libmpg123-static.a Beryll_engine/libs/imgui/libImGUI-static.a Beryll_engine/libs/assimp/code/libassimp.a Beryll_engine/libs/assimp/contrib/zlib/libzlibstatic.a Beryll_engine/libs/assimp/contrib/irrXML/libIrrXML.a Beryll_engine/libs/sqlite/libsqlite3-static.a Beryll_engine/libs/bullet/libbullet-static.a Beryll_engine/libs/bullet/LinearMath/libLinearMath-static.a Beryll_engine/libs/bullet/Bullet3Common/libBullet3Common-static.a Beryll_engine/libs/bullet/BulletCollision/libBulletCollision-static.a Beryll_engine/libs/bullet/BulletDynamics/libBulletDynamics-static.a Beryll_engine/libs/bullet/BulletSoftBody/libBulletSoftBody-static.a Beryll_engine/libs/bullet/BulletInverseDynamics/libBulletInverseDynamics-static.a -latomic -lm && cd ."
Beryll_engine/libs/bullet/BulletDynamics/libBulletDynamics-static.a(btTypedConstraint.cpp.o): In function `~btRigidBody':
D:/Programmy/Android/android-project/app/jni/Beryll_engine/libs/bullet/BulletDynamics/..\BulletDynamics/Dynamics/btRigidBody.h:178: undefined reference to `btCollisionObject::~btCollisionObject()'
Beryll_engine/libs/bullet/BulletDynamics/libBulletDynamics-static.a(btRigidBody.cpp.o): In function `btRigidBody':
D:/Programmy/Android/android-project/app/jni/Beryll_engine/libs/bullet/BulletDynamics/Dynamics/btRigidBody.cpp:29: undefined reference to `btCollisionObject::btCollisionObject()'
D:/Programmy/Android/android-project/app/jni/Beryll_engine/libs/bullet/BulletDynamics/Dynamics/btRigidBody.cpp:32: undefined reference to `btCollisionObject::~btCollisionObject()'
D:/Programmy/Android/android-project/app/jni/Beryll_engine/libs/bullet/BulletDynamics/Dynamics/btRigidBody.cpp:34: undefined reference to `btCollisionObject::btCollisionObject()'
D:/Programmy/Android/android-project/app/jni/Beryll_engine/libs/bullet/BulletDynamics/Dynamics/btRigidBody.cpp:38: undefined reference to `btCollisionObject::~btCollisionObject()'
Beryll_engine/libs/bullet/BulletDynamics/libBulletDynamics-static.a(btRigidBody.cpp.o): In function `btRigidBody::serialize(void*, btSerializer*) const':
D:/Programmy/Android/android-project/app/jni/Beryll_engine/libs/bullet/BulletDynamics/Dynamics/btRigidBody.cpp:469: undefined reference to `btCollisionObject::serialize(void*, btSerializer*) const'
Beryll_engine/libs/bullet/BulletDynamics/libBulletDynamics-static.a(btRigidBody.cpp.o):(.data.rel.ro._ZTI11btRigidBody+0x10): undefined reference to `typeinfo for btCollisionObject'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

But when i compiled bullet with help of Android.mk file:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_CFLAGS := $(LOCAL_C_INCLUDES:%=-I%) -DUSE_PTHREADS -mfpu=neon -mfloat-abi=softfp -pthread -DSCE_PFX_USE_SIMD_VECTORMATH

# apply these flags if needed 
# -ffast-math -funsafe-math-optimizations

# apply this to disable optimization
# TARGET_CFLAGS := $(TARGET_CFLAGS) -O0

# apply these 2 to turn on assembly output (*.c/*.cpp to *.s file)
#compile-cpp-source = $(eval $(call ev-compile-cpp-source,$1,$(1:%$(LOCAL_CPP_EXTENSION)=%.s)))
#TARGET_CFLAGS := $(TARGET_CFLAGS) -S

# Enable or disable NEON. Don't forget to apply, or not apply, -mfpu=neon and -mfloat-abi=softfp
# flags in addition, e.g., if this is true both of those need to be included in LOCAL_CFLAGS
# to avoid the possibility that ndk-build will "forget" to add them on some files
LOCAL_ARM_NEON := true

TARGET_CFLAGS := $(filter-out -ffpu=vfp,$(TARGET_CFLAGS))

# setup to build static library
LOCAL_MODULE := bulletPhysics

LOCAL_C_INCLUDES :=  $(LOCAL_PATH)/src

#find all the file recursively under jni/
FILE_LIST := $(wildcard \
        $(LOCAL_PATH)/src/LinearMath/*.cpp \
        $(LOCAL_PATH)/src/Bullet3Common/*.cpp \
        $(LOCAL_PATH)/src/BulletCollision/BroadphaseCollision/*.cpp \
        $(LOCAL_PATH)/src/BulletCollision/CollisionDispatch/*.cpp \
        $(LOCAL_PATH)/src/BulletCollision/CollisionShapes/*.cpp \
        $(LOCAL_PATH)/src/BulletCollision/NarrowPhaseCollision/*.cpp \
        $(LOCAL_PATH)/src/BulletDynamics/ConstraintSolver/*.cpp \
        $(LOCAL_PATH)/src/BulletDynamics/Dynamics/*.cpp \
        $(LOCAL_PATH)/src/BulletDynamics/Featherstone/*.cpp \
        $(LOCAL_PATH)/src/BulletDynamics/MLCPSolvers/*.cpp \
        $(LOCAL_PATH)/src/BulletDynamics/Vehicle/*.cpp \
        $(LOCAL_PATH)/src/BulletDynamics/Character/*.cpp \
        $(LOCAL_PATH)/src/BulletSoftBody/*.cpp \
        $(LOCAL_PATH)/src/BulletInverseDynamics/*.cpp \
        $(LOCAL_PATH)/src/BulletInverseDynamics/details/*.cpp \
        )
LOCAL_SRC_FILES := $(FILE_LIST:$(LOCAL_PATH)/%=%)

include $(BUILD_STATIC_LIBRARY)

everything works and linked good.

1. Should i use extra settings for CMAKE?
2. Why linker dont see btCollisionObject constructor and destructor?
3. Does linker see rest of compiled static lib?
4. Can be problem that i finally link static lib to shared?

Answer 1

I found what is problem. In bullet one module reference something in other module:
class btRigidBody in BulletDynamics/Dynamics/btRigidBody.h inherit class btCollisionObject from BulletCollision/CollisionDispatch/btCollisionObject.h.

That mean linking order is very important. When you linking BulletDynamics-static, BulletCollision-static must be already linked !

I think it important for shared lib too.

I changed order for BulletDynamics-static and BulletCollision-static in target_link_libraries() and everything linked correctly.