clang flag "--coverage" doesn't work in API level < 21, __strncpy_chk2 not found

[clouds56]

Description

Create a new Projects with c++ support, and minSdk 19 (<21), add flag "--coverage" for both link and cppflags in CMakelist.txt.

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --coverage")
set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} --coverage")

Compile failed with:

 C:\Users\clouds\AppData\Local\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\..\lib64\clang\3.8.275480\lib\linux\libclang_rt.profile-mipsel-android.a(InstrProfilingUtil.o): In function `strncpy(char*, char const* pass_object_size1, unsigned int pass_object_size1)':
  out/stage2/soong/ndk/sysroot/usr/include/string.h:351: undefined reference to `__strncpy_chk2'
  clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
  ninja: build stopped: subcommand failed.

The "--coverage" option should support all platform.

Details

nm -gC libclang_rt.profile-i686-android.a|grep chk2 gives:

U __stack_chk_fail
U __stack_chk_fail
U __strlen_chk
U __vsnprintf_chk
U __stack_chk_fail
U __strncpy_chk2
U __stack_chk_fail

while it starts from android-21:
nm -gC ./android-21/arch-x86/usr/lib/libc.so|grep chk

0000a750 T __FD_CLR_chk
0000a760 T __FD_ISSET_chk
0000a770 T __FD_SET_chk
0000a780 T __fgets_chk
0000a990 T __memcpy_chk
0000a9a0 T __memmove_chk
0000a9b0 T __memset_chk
0000ac80 T __read_chk
0000aca0 T __recvfrom_chk
0000aeb0 T __snprintf_chk
0000aed0 T __sprintf_chk
0000aee0 T __stack_chk_fail
00010014 B __stack_chk_guard
0000af00 T __stpcpy_chk
0000af10 T __stpncpy_chk
0000af20 T __stpncpy_chk2
0000af30 T __strcat_chk
0000af40 T __strchr_chk
0000af50 T __strcpy_chk
0000af60 T __strlcat_chk
0000af70 T __strlcpy_chk
0000af80 T __strlen_chk
0000af90 T __strncat_chk
0000afa0 T __strncpy_chk
0000afb0 T __strncpy_chk2
0000afc0 T __strrchr_chk
0000b120 T __umask_chk
0000b130 T __vsnprintf_chk
0000b140 T __vsprintf_chk

in ./android-21/arch-x86/usr/include/string.h (start from android-21):

extern char* __strncpy_chk2(char* __restrict, const char* __restrict, size_t, size_t, size_t);

__BIONIC_FORTIFY_INLINE
char* strncpy(char* __restrict dest, const char* __restrict src, size_t n) {
    size_t bos_dest = __bos(dest);
    size_t bos_src = __bos(src);

    if (bos_src == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __builtin___strncpy_chk(dest, src, n, bos_dest);
    }

    if (__builtin_constant_p(n) && (n <= bos_src)) {
        return __builtin___strncpy_chk(dest, src, n, bos_dest);
    }

    size_t slen = __builtin_strlen(src);
    if (__builtin_constant_p(slen)) {
        return __builtin___strncpy_chk(dest, src, n, bos_dest);
    }

    return __strncpy_chk2(dest, src, n, bos_dest, bos_src);
}

Full error output:

FAILURE: Build failed with an exception.

What went wrong:
Execution failed for task ':app:externalNativeBuildDebug'.
Build command failed.
Error while executing process C:\Users\clouds\AppData\Local\Android\android-sdk\cmake\3.6.3155560\bin\cmake.exe with arguments {--build D:\Projects\PDF\Coverage\Test\app.externalNativeBuild\cmake\debug\mips --target native-lib}

[1/2] Building CXX object CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o
[2/2] Linking CXX shared library ........\build\intermediates\cmake\debug\obj\mips\libnative-lib.so
FAILED: cmd.exe /C "cd . && C:\Users\clouds\AppData\Local\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe --target=mipsel-none-linux-android --gcc-toolchain=C:/Users/clouds/AppData/Local/Android/android-sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64 --sysroot=C:/Users/clouds/AppData/Local/Android/android-sdk/ndk-bundle/platforms/android-19/arch-mips -fPIC -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -mips32 -Wa,--noexecstack -Wformat -Werror=format-security -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -mips32 -Wa,--noexecstack -Wformat -Werror=format-security --coverage -O0 -fno-limit-debug-info -O0 -fno-limit-debug-info -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings "-LC:/Users/clouds/AppData/Local/Android/android-sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/32/mips-r1" -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings "-LC:/Users/clouds/AppData/Local/Android/android-sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/32/mips-r1" -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now --coverage -shared -Wl,-soname,libnative-lib.so -o ........\build\intermediates\cmake\debug\obj\mips\libnative-lib.so CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o -llog -lm "C:/Users/clouds/AppData/Local/Android/android-sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/mips/libgnustl_static.a" && cd ."
C:\Users\clouds\AppData\Local\Android\android-sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin..\lib64\clang\3.8.275480\lib\linux\libclang_rt.profile-mipsel-android.a(InstrProfilingUtil.o): In function 'strncpy(char*, char const* pass_object_size1, unsigned int pass_object_size1)':
out/stage2/soong/ndk/sysroot/usr/include/string.h:351: undefined reference to '__strncpy_chk2'
clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

Environment Details

Not all of these will be relevant to every bug, but please provide as much
information as you can.

• NDK Version: 14.1.3816874
• Build sytem: cmake
• Host OS: Windows 10
• Compiler: Clang 3.8.275480
• ABI: x86
• STL: N/A
• NDK API level: 17
• Device API level: N/A

[DanAlbert]

@pirama-arumuga-nainar @stephenhines: I think we just need to start building libclang_rt.profile with the NDK rather than with the platform.

[DanAlbert]

https://android-review.googlesource.com/c/456136

[DanAlbert]

Fixed in r17 beta 1.