CODEWITHSUNDEEP
android-ndkfortranlapackblas
kb1ooo
kb1ooo

Reputation: 8872

Unresolved sincos during build of LAPACK

Following the instructions here I have built a Fortran enabled NDK toolchain (OSX, NDK-7b) with the goal of building LAPACK/BLAS.

Using android-cmake with the 3.4.0 net lib source it seems that I'm nearly successful. However, the BLAS build fails when linking one of the tests (with an error stating unresolved sincos and sincosf). A little searching reveals that these functions are not available in legacy Android versions. I'm wondering what is the best way to resolve these functions?

Below is and example of a linking error:

cd /Users/marc/software/lapack-3.4.0/Android/BLAS/TESTING && /opt/local/bin/cmake -E cmake_link_script CMakeFiles/xblat2c.dir/link.txt --verbose=1 /opt/local/share/java/android-ndk-macosx/toolchains/arm-linux-androideabi-4.7.0/prebuilt/darwin-x86/bin/arm-linux-androideabi-gfortran -Wl,--gc-sections -Wl,-z,nocopyreloc -Wl,--fix-cortex-a8 -Wl,--no-undefined -lstdc++ -lsupc++ CMakeFiles/xblat2c.dir/cblat2.f.o -o ../../bin/xblat2c -rdynamic -L/Users/marc/software/lapack-3.4.0/Android/systemlibs/armeabi-v7a -L/opt/local/share/java/android-ndk-macosx/toolchains/arm-linux-androideabi-4.7.0/prebuilt/darwin-x86/user/libs/armeabi-v7a ../../lib/libblas.a -lm -Wl,-rpath,/Users/marc/software/lapack-3.4.0/Android/systemlibs/armeabi-v7a:/opt/local/share/java/android-ndk-macosx/toolchains/arm-linux-androideabi-4.7.0/prebuilt/darwin-x86/user/libs/armeabi-v7a /opt/local/share/java/android-ndk-macosx/toolchains/arm-linux-androideabi-

4.7.0/prebuilt/darwin-x86/lib/gcc/arm-linux-androideabi/4.7.0/../../../../arm-linux-androideabi/lib/libgfortran.a(c99_functions.o): In function cexpf': /opt/local/share/java/android-ndk-macosx/src/build/../gcc/gcc-4.7.0/libgfortran/intrinsics/c99_functions.c:910: undefined reference tosincosf'

Upvotes: 3

Views: 1756

Answers (1)

Tobias
Tobias

Reputation: 36

GCC needs to know at compile time whether sincos is available or not. It does so based on the target. In case of the target triplet arm-linux-androideabi, it looks at gcc/config/linux.h and finds there:

/* Whether we have sincos that follows the GNU extension.  */
#undef TARGET_HAS_SINCOS
#define TARGET_HAS_SINCOS (OPTION_GLIBC || OPTION_BIONIC)

The reason for the inclusion of Bionic is that Android 2.3 added support for sincosf/sincos/sincosl [1]. Thus, you can either update Bionic or you patch GCC to assume that no sincos is available; cf. also [2].

[1] http://source-android.frandroid.com/bionic/libc/docs/CHANGES.TXT

[2] https://bugs.launchpad.net/linaro-android/+bug/908125

Upvotes: 2

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