1 ## 3.3\. Native API Compatibility 2 3 Device implementers are: 4 5 Native code compatibility is challenging. For this reason, 6 device implementers are: 7 8 * [SR] STRONGLY RECOMMENDED to use the implementations of the libraries 9 listed below from the upstream Android Open Source Project. 10 11 ### 3.3.1\. Application Binary Interfaces 12 13 Managed Dalvik bytecode can call into native code provided in the application 14 `.apk` file as an ELF `.so` file compiled for the appropriate device hardware 15 architecture. As native code is highly dependent on the underlying processor 16 technology, Android defines a number of Application Binary Interfaces (ABIs) in 17 the Android NDK. 18 19 Device implementations: 20 21 * [C-0-1] MUST be compatible with one or more defined ABIs and implement 22 compatibility with the Android NDK. 23 * [C-0-2] MUST include support for code running in the managed environment to 24 call into native code, using the standard Java Native Interface (JNI) 25 semantics. 26 * [C-0-3] MUST be source-compatible (i.e. header-compatible) and 27 binary-compatible (for the ABI) with each required library in the list 28 below. 29 * [C-0-4] MUST support the equivalent 32-bit ABI if any 64-bit ABI is 30 supported. 31 * [C-0-5] MUST accurately report the native Application Binary Interface 32 (ABI) supported by the device, via the `android.os.Build.SUPPORTED_ABIS`, 33 `android.os.Build.SUPPORTED_32_BIT_ABIS`, and 34 `android.os.Build.SUPPORTED_64_BIT_ABIS` parameters, each a comma separated 35 list of ABIs ordered from the most to the least preferred one. 36 * [C-0-6] MUST report, via the above parameters, only those ABIs documented 37 and described in the latest version of the 38 [Android NDK ABI Management documentation]( 39 https://developer.android.com/ndk/guides/abis.html), and MUST include 40 support for the [Advanced SIMD]( 41 http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html) 42 (a.k.a. NEON) extension. 43 * [C-0-7] MUST make all the following libraries, providing native APIs, 44 available to apps that include native code: 45 46 * libaaudio.so (AAudio native audio support) 47 * libandroid.so (native Android activity support) 48 * libc (C library) 49 * libcamera2ndk.so 50 * libdl (dynamic linker) 51 * libEGL.so (native OpenGL surface management) 52 * libGLESv1\_CM.so (OpenGL ES 1.x) 53 * libGLESv2.so (OpenGL ES 2.0) 54 * libGLESv3.so (OpenGL ES 3.x) 55 * libicui18n.so 56 * libicuuc.so 57 * libjnigraphics.so 58 * liblog (Android logging) 59 * libmediandk.so (native media APIs support) 60 * libm (math library) 61 * libOpenMAXAL.so (OpenMAX AL 1.0.1 support) 62 * libOpenSLES.so (OpenSL ES 1.0.1 audio support) 63 * libRS.so 64 * libstdc++ (Minimal support for C++) 65 * libvulkan.so (Vulkan) 66 * libz (Zlib compression) 67 * JNI interface 68 69 * [C-0-8] MUST NOT add or remove the public functions for the native libraries 70 listed above. 71 * [C-0-9] MUST list additional non-AOSP libraries exposed directly to 72 third-party apps in `/vendor/etc/public.libraries.txt`. 73 * [C-0-10] MUST NOT expose any other native libraries, implemented and 74 provided in AOSP as system libraries, to third-party apps targeting API 75 level 24 or higher as they are reserved. 76 * [C-0-11] MUST export all the OpenGL ES 3.1 and [Android Extension Pack]( 77 http://developer.android.com/guide/topics/graphics/opengl.html#aep) 78 function symbols, as defined in the NDK, through the `libGLESv3.so` library. 79 Note that while all the symbols MUST be present, section 7.1.4.1 describes 80 in more detail the requirements for when the full implementation of each 81 corresponding functions are expected. 82 * [C-0-12] MUST export function symbols for the core Vulkan 1.0 function 83 symobls, as well as the `VK_KHR_surface`, `VK_KHR_android_surface`, 84 `VK_KHR_swapchain`, `VK_KHR_maintenance1`, and 85 `VK_KHR_get_physical_device_properties2` extensions through the 86 `libvulkan.so` library. Note that while all the symbols MUST be present, 87 section 7.1.4.2 describes in more detail the requirements for when the full 88 implementation of each corresponding functions are expected. 89 * SHOULD be built using the source code and header files available in the 90 upstream Android Open Source Project 91 92 Note that future releases of the Android NDK may introduce support for 93 additional ABIs. 94 95 ### 3.3.2. 32-bit ARM Native Code Compatibility 96 97 If device implementations are 64-bit ARM devices, then: 98 99 * [C-1-1] Although the ARMv8 architecture deprecates several CPU operations, 100 including some operations used in existing native code, the following 101 deprecated operations MUST remain available to 32-bit native ARM code, 102 either through native CPU support or through software emulation: 103 104 * SWP and SWPB instructions 105 * SETEND instruction 106 * CP15ISB, CP15DSB, and CP15DMB barrier operations 107 108 If device implementations include a 32-bit ARM ABI, they: 109 110 * [C-2-1] MUST include the following lines in `/proc/cpuinfo` when it is read 111 by 32-bit ARM applications to ensure compatibility with applications built 112 using legacy versions of Android NDK. 113 114 * `Features: `, followed by a list of any optional ARMv7 CPU features 115 supported by the device. 116 * `CPU architecture: `, followed by an integer describing the device's 117 highest supported ARM architecture (e.g., "8" for ARMv8 devices). 118 119 * SHOULD not alter `/proc/cpuinfo` when read by 64-bit ARM or non-ARM 120 applications.
