IssueTracker

I'm using renderscript for audio dsp processing. It works well until I decided to bump up renderscriptTargetApi version from 19 to 24 in an attempt to make use of newer renderscript APIs in a backward compatible way.

There is no issue with the compilation, but at runtime, logcat shows error like this

05-31 19:40:23.097 8661-8734/com.example.audio.test E/RenderScript: Unable to open shared library (/data/user/0/com.example.audio.test//lib/librs.xx.so): dlopen failed: library "libRSSupportIO.so" not found

If I have renderscriptTargetApi as 19 or 20, my apk has librs.xx.so and there is no error. If I bump it to 21, 23, or 24, librs.xx.so is not generated and thus I have this runtime error.

I'm using renderscript through NDK i.e. C++. Also using CMake. There aren't instructions I could find to make use of renderscript support library through NDK. All instructions assume that the support library is used through Java.

This is from build.gradle

    ndk {
        abiFilters 'armeabi-v7a', 'x86'
    }

    renderscriptTargetApi 24
    renderscriptSupportModeEnabled true
    renderscriptNdkModeEnabled true

CMakeLists.txt has

    add_library (dsp SHARED
      ${SRC_PATH}/dsp.cpp
      ${SRC_RS_PATH}/xx.rs ${SRC_RS_GENERATED_PATH}/ScriptC_xx.cpp)
   
    target_compile_options(dsp PRIVATE
      -std=c++11 -stdlib=libc++ -fno-rtti -fexceptions -Ofast)
   
    target_link_libraries(dsp RScpp_static dl ${log-lib})

This is xx.rs

    #pragma version(1)
    #pragma rs java_package_name(com.example.audio)
    #pragma rs_fp_relaxed
   
    float RS_KERNEL my_kernel(float in, uint32_t x) {
        // ...
   }

This is how the kernel is called from C++

    sp<RS> rs = new RS();
    rs->init(app_cache_dir);
   
    sp<const Element> e = Element::F32(rs);
    sp<const Type> t = Type::create(rs, e, 44100*10, 0, 0);
   
    sp<Allocation> inAlloc = Allocation::createTyped(rs, t);
    inAlloc->copy1DFrom(input);
   
    sp<Allocation> outAlloc = Allocation::createTyped(rs, t);
   
    ScriptC_xx *script = new ScriptC_xx(rs);
    script->forEach_xx(inAlloc, outAlloc);
   
    outAlloc->copy1DTo(output);

As you see, it is pretty basic usage scenario of renderscript. It works well with renderscriptTargetApi in 19 or 20. If I bump up the version, build is still successful, but librs.xx.so file is not generated. At runtime, we see the above mentioned error about this .so file.

What am I missing here? I tried manipulating my minSdkVersion which I think is unrelated to renderscript target api. It didn't help.

How can I use the newer renderscript APIs in the backward compatible manner from NDK? Any help is appreciated.

Repo to reproduce the issue
https://github.com/rpattabi/renderscript-ndk-cmake