Changelog r26

Changelog

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For Android Studio issues, follow the docs on the Android Studio site.

If you're a build system maintainer that needs to use the tools in the NDK directly, see the build system maintainers guide.

Announcements

• KitKat (APIs 19 and 20) is no longer supported. The minimum OS supported by the NDK is Lollipop (API level 21). See Issue 1751 for details.
• libc++ has been updated. The NDK's libc++ now comes directly from our LLVM toolchain, so every future LLVM update is also a libc++ update. Future changelogs will not explicitly mention libc++ updates.

r26d

• Issue 1994: Fixed ndk-gdb/ndk-lldb to use the correct path for make and other tools.

r26c

• Updated LLVM to clang-r487747e. See AndroidVersion.txt and clang_source_info.md in the toolchain directory for version information.
  • Issue 1928: Fixed Clang crash in instruction selection for 32-bit armv8 floating point.
  • Issue 1953: armeabi-v7a libc++ libraries are once again built as thumb.

r26b

• Updated LLVM to clang-r487747d. See AndroidVersion.txt and clang_source_info.md in the toolchain directory for version information.
  • This update was intended to be included in r26 RC 1. The original release noted these fixes in the changelog, but the new toolchain had not actually been included.
  • Issue 1907: HWASan linker will be used automatically for minSdkVersion 34 or higher.
  • Issue 1909: Fixed ABI mismatch between function-multi-versioning and ifunc resolvers.
• Issue 1938: Fixed ndk-stack to use the correct path for llvm-symbolizer and other tools.

Changes

• Updated LLVM to clang-r487747c. See AndroidVersion.txt and clang_source_info.md in the toolchain directory for version information.

  • Clang now treats -Wimplicit-function-declaration as an error rather than a warning in C11 and newer. Clang's default C standard is 17, so this is a change in default behavior compared to older versions of Clang, but is the behavior defined by C99.

    If you encounter these errors when upgrading, you most likely forgot an #include. If you cannot (or do not want to) fix those issues, you can revert to the prior behavior with -Wno-error=implicit-function-declaration.

    C++ users are unaffected. This has never been allowed in C++.

    See https://reviews.llvm.org/D122983 for more details.

  • Issue 1298: Fixed seccomp error with ASan on x86_64 devices.

  • Issue 1530: Updated libc++ to match LLVM version.

  • Issue 1565: Fixed lldb ncurses issue with terminal database on Darwin.

  • Issue 1677: Fixed Clang crash in optimizer.

  • Issue 1679: Clang will now automatically enable ELF TLS for minSdkVersion 29 or higher.

  • Issue 1834: Fixed Clang crash during SVE conversions.

  • Issue 1860: Fixed miscompilation affecting armv7.

  • Issue 1861: Fixed front end crash in Clang.

  • Issue 1862: Fixed Clang crash for aarch64 with -Os.

  • Issue 1880: Fixed crash in clang-format.

  • Issue 1883: Fixed crash when incorrectly using neon intrinsics.

• Version scripts that name public symbols that are not present in the library will now emit an error by default for ndk-build and the CMake toolchain file. Build failures caused by this error are likely a bug in your library or a mistake in the version script. To revert to the earlier behavior, pass -DANDROID_ALLOW_UNDEFINED_VERSION_SCRIPT_SYMBOLS=ON to CMake or set LOCAL_ALLOW_UNDEFINED_VERSION_SCRIPT_SYMBOLS := true in your Android.mk file. For other build systems, see the secion titled "Version script validation" in the build system maintainers guide.
• [Issue 873]: Weak symbols for API additions is supported. Provide __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__ as an option.
• Issue 1400: NDK paths with spaces will now be diagnosed by ndk-build on Windows. This has never been supported for any OS, but the error message wasn't previously working on Windows either.
• Issue 1764: Fixed Python 3 incompatibility when using ndk-gdb with -f.
• Issue 1803: Removed useless strtoq and strtouq from the libc stub libraries. These were never exposed in the header files, but could confuse some autoconf like systems.
• Issue 1852: Fixed ODR issue in linux/time.h.
• Issue 1878: Fixed incorrect definition of WIFSTOPPED.
• ndk-build now uses clang rather than clang++ when linking modules that do not have C++ sources. There should not be any observable behavior differences because ndk-build previously handled the C/C++ linking differences itself.
• ndk-build now delegates C++ stdlib linking to the Clang driver. It is unlikely that this will cause any observable behavior change, but any new behavior will more closely match CMake and other build systems.

Known Issues

This is not intended to be a comprehensive list of all outstanding bugs.

• Issue 360: thread_local variables with non-trivial destructors will cause segfaults if the containing library is dlcloseed. This was fixed in API 28, but code running on devices older than API 28 will need a workaround. The simplest fix is to stop calling dlclose. If you absolutely must continue calling dlclose, see the following table:

  	Pre-API 23	APIs 23-27	API 28+
  No workarounds	Works for static STL	Broken	Works
  -Wl,-z,nodelete	Works for static STL	Works	Works
  No dlclose	Works	Works	Works

  If your code must run on devices older than M (API 23) and you cannot use the static STL (common), the only fix is to not call dlclose, or to stop using thread_local variables with non-trivial destructors.

  If your code does not need to run on devices older than API 23 you can link with -Wl,-z,nodelete, which instructs the linker to ignore dlclose for that library. You can backport this behavior by not calling dlclose.

  The fix in API 28 is the standardized inhibition of dlclose, so you can backport the fix to older versions by not calling dlclose.

• Issue 988: Exception handling when using ASan via wrap.sh can crash. To workaround this issue when using libc++_shared, ensure that your application's libc++_shared.so is in LD_PRELOAD in your wrap.sh as in the following example:

  #!/system/bin/sh
  HERE="$(cd "$(dirname "$0")" && pwd)"
  export ASAN_OPTIONS=log_to_syslog=false,allow_user_segv_handler=1
  ASAN_LIB=$(ls $HERE/libclang_rt.asan-*-android.so)
  if [ -f "$HERE/libc++_shared.so" ]; then
      # Workaround for https://github.com/android/ndk/issues/988.
      export LD_PRELOAD="$ASAN_LIB $HERE/libc++_shared.so"
  else
      export LD_PRELOAD="$ASAN_LIB"
  fi
  "$@"

  There is no known workaround for libc++_static.

  Note that because this is a platform bug rather than an NDK bug this cannot be fixed with an NDK update. This workaround will be necessary for code running on devices that do not contain the fix, and the bug has not been fixed even in the latest release of Android.