Halide AOT for OpenCL works fine as static library but not as shared object - shared-libraries

Question

I try to compile the code below both to static library and to object file:
Halide::Func f("f");
Halide::Var x("x");
f(x) = x;
f.gpu_tile(x, 4);
f.bound(x, 0, 16);
Halide::Target target = Halide::get_target_from_environment();
target.set_feature(Halide::Target::OpenCL);
target.set_feature(Halide::Target::Debug);
// f.compile_to_static_library("mylib", {}, "f", target);
// f.compile_to_file("mylib", {}, "f", target);
In case of static linking all works fine and output result is correct:
Halide::Buffer<int> output(16);
f(output.raw_buffer());
output.copy_to_host();
std::cout << output(10) << std::endl;
But when I try link object file into shared object,
gcc -shared -pthread mylib.o -o mylib.so
And open it from code (Ubuntu 16.04),
void* handle = dlopen("mylib.so", RTLD_NOW);
int (*func)(halide_buffer_t*);
*(void**)(&func) = dlsym(handle, "f");
func(output.raw_buffer());
I receive CL_INVALID_MEM_OBJECT error. Here is the debugging log:
CL: halide_opencl_init_kernels (user_context: 0x0, state_ptr: 0x7f1266b5a4e0, program: 0x7f1266957480, size: 1577
load_libopencl (user_context: 0x0)
Loaded OpenCL runtime library: libOpenCL.so
create_opencl_context (user_context: 0x0)
Got platform 'Intel(R) OpenCL', about to create context (t=6249430)
Multiple CL devices detected. Selecting the one with the most cores.
Device 0 has 20 cores
Device 1 has 4 cores
Selected device 0
device name: Intel(R) HD Graphics
device vendor: Intel(R) Corporation
device profile: FULL_PROFILE
global mem size: 1630 MB
max mem alloc size: 815 MB
local mem size: 65536
max compute units: 20
max workgroup size: 256
max work item dimensions: 3
max work item sizes: 256x256x256x0
clCreateContext -> 0x1899af0
clCreateCommandQueue 0x1a26a80
clCreateProgramWithSource -> 0x1a26ab0
clBuildProgram 0x1a26ab0 -D MAX_CONSTANT_BUFFER_SIZE=854799155 -D MAX_CONSTANT_ARGS=8
Time: 1.015832e+02 ms
CL: halide_opencl_run (user_context: 0x0, entry: kernel_f_s0_x___deprecated_block_id_x___block_id_x, blocks: 4x1x1, threads: 4x1x1, shmem: 0
clCreateKernel kernel_f_s0_x___deprecated_block_id_x___block_id_x -> Time: 1.361700e-02 ms
clSetKernelArg 0 4 [0x2e00010000000000 ...] 0
clSetKernelArg 1 8 [0x2149040 ...] 1
Mapped dev handle is: 0x2149040
Error: CL: clSetKernelArg failed: CL_INVALID_MEM_OBJECT
Aborted (core dumped)
Thank you very much for help! Commit state c7375fa. I'm pleasure provide extra information if it will be necessary.

Answer 1

Solution: In this case we have runtime duplication. Load shared object with flag RTLD_DEEPBIND.
void* handle = dlopen("mylib.so", RTLD_NOW | RTLD_DEEPBIND);
RTLD_DEEPBIND (since glibc 2.3.4)
Place the lookup scope of the symbols in this library ahead of the global scope. This means that a self-contained library will use its own symbols in preference to global symbols with the same name contained in libraries that have already been loaded. This flag is not specified in POSIX.1-2001.
https://linux.die.net/man/3/dlopen