Develop Reference

Swift for Android: `ld` cannot find `-lgcc` in swift for android compilation linking step

Moving from Unix Stack Exchange to here, my bounty there failed:
I'm trying to compile Swift code on Ubuntu 16.04 LTS, following these instructions fairly closely. I was able to download the NDK r14 okay, download the libicu tools and build them, and download the swift source and build that against the libicu tools. I get all the way down to compiling actual swift code and get this:
#build.sh
#(I symlinked the androideabi ld.gold to /usr/bin/ld.armv7, based on a swift bug ticket's advice. Thats the only thing different from the instructions)
/home/mike/workspace/swift-source/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swiftc \
-use-ld=armv7 \
-tools-directory /home/mike/workspace/android-ndk-r14/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/arm-linux-androideabi/bin \
-target armv7-none-linux-androideabi \
-sdk /home/mike/workspace/android-ndk-r14/platforms/android-21/arch-arm \
-L /home/mike/workspace/android-ndk-r14/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a \
-L /home/mike/workspace/android-ndk-r14/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9 \
hello.swift
#output
mike#mike-VirtualBox:~/workspace/HelloSwift$ ./build.sh
/usr/bin/ld.armv7: error: cannot find -lgcc
/usr/bin/ld.armv7: error: cannot find -lgcc
/usr/bin/ld.armv7: error: cannot find -lgcc
/usr/bin/ld.armv7: error: cannot find -lgcc
I don't have a ton of experience being this far down the toolchain, but I definitely have gcc installed, and gcc-multilib, and LD_LIBRARY_PATH set to help ld find gcc, and I've rebuild the ld cache with ldconfig.
When I run sudo ldconfig -p | grep gcc, I get
libgccpp.so.1 (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libgccpp.so.1
libgcc_s.so.1 (libc6,x32) => /usr/libx32/libgcc_s.so.1
libgcc_s.so.1 (libc6,x86-64) => /lib/x86_64-linux-gnu/libgcc_s.so.1
libgcc_s.so.1 (libc6) => /usr/lib32/libgcc_s.so.1
and a few other things named libuno_<something with gcc in it>

In the newest version of android-ndk-r14b, the location of required gcc library is at:
/path/to/android-ndk-r14b/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9.x
The Swift Android docs seem to be outdated, and point to:
/path/to/android-ndk-r14b/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9.
Making sure you link against this correct path in your call to swiftc should solve the problem.
(I've submitted this pull request to ensure nobody else runs into this as well.)

How to compile Boost 1.61 for Android NDK 11

I want to install compile Boost 1.61 with clang 3.6 for android with the NDK 11 but this software : https://github.com/moritz-wundke/Boost-for-Android isn't updated and doesn't support this versions.
I want to know if anyone has managed to this !
Thank you !

Build boost_1_62_0 for Android-21 under Windows64.
Assuming NDK installed to C:\Programs\Android\sdk\ndk-bundle and boost in c:\boost_1_62_0.
Install mingw: using msys2-x86_64 from MSYS2
Install build tools from mingw prompt (something like this):
$ pacman -S gcc binutils
Create android.clang.jam file in C:\boost_1_62_0\ with such text content:
import os ;
local AndroidNDKRoot = C:/Programs/Android/sdk/ndk-bundle ;
using clang : android
:
C:/Programs/Android/toolchain21/bin/clang++
:
<compileflags>-fexceptions
<compileflags>-frtti
<compileflags>-fpic
<compileflags>-ffunction-sections
<compileflags>-funwind-tables
<compileflags>-Wno-psabi
<compileflags>-march=armv7-a
<compileflags>-mfloat-abi=softfp
<compileflags>-mfpu=vfpv3-d16
<compileflags>-fomit-frame-pointer
<compileflags>-fno-strict-aliasing
<compileflags>-finline-limit=64
<compileflags>-I$(AndroidNDKRoot)/platforms/android-21/arch-arm/usr/include
<compileflags>-Wa,--noexecstack
<compileflags>-DANDROID
<compileflags>-D__ANDROID__
<compileflags>-DNDEBUG
<compileflags>-O2
#<compileflags>-g
<compileflags>-I$(AndroidNDKRoot)/sources/cxx-stl/gnu-libstdc++/4.9/include
<compileflags>-I$(AndroidNDKRoot)/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi/include
<architecture>arm
<compileflags>-fvisibility=hidden
<compileflags>-fvisibility-inlines-hidden
<compileflags>-fdata-sections
<cxxflags>-D__arm__
<cxxflags>-D_REENTRANT
<cxxflags>-D_GLIBCXX__PTHREADS
;
Setup boost from mingw prompt:
$ export NDK=/c/Programs/Android/sdk/ndk-bundle
$ echo ensure msi-installed Python is on path (not msys version):
$ export PATH=/c/Python27:$PATH
$ $NDK/build/tools/make_standalone_toolchain.py --arch arm --api 21 --install-dir /c/Programs/Android/toolchain21
$ ./bootstrap.sh --with-toolset=gcc
$ ./b2 --user-config=android.clang.jam threading=multi link=static \
runtime-link=static toolset=clang-android target-os=linux \
threadapi=pthread --stagedir=android --with-chrono \
--with-program_options --with-system --with-thread --with-random \
--with-regex

Yes, the repository you mentioned is apparently not maintained anymore. The author also seems not to answer any mails on the subject. If you look you'll see that each new boost version supported there required a lot of work (many special flags in the config files). That's presumably why he doesn't have time to maintain it any longer.
I also tried to update to 1.64 using a fork but gave up after countless error messages and instead used a different method based on a crystax script. Its simple and should work for pretty much any version. You can find the details and the script (simple and painless to execute) here: http://silverglint.com/boost-for-android/
Works with clang and gcc.
Also included is a sample app that shows you how to use the boost binaries thus built.

Building OpenSSL for Android (ARMv7) on Win32

How can I build OpenSSL for Android ARM v7 (using Android NDK) on Win32?

Until the OpenSSL's wiki and setenv-android.sh are updated accordingly, I'll publish the recipe here. The required fixes to the process are:
Update setenv-android.sh to support Windows.
Update PATH to use Android NDK's (mingw) GNU make (rather than Cygwin's).
Invoke make with a Windows-style path to Cygwin's perl.
This recipe will be a strange hybrid of Cygwin and mingw (since Android NDK gcc toolchains for win32 are mingw). I'm assuming a Windows x86_64 build of the Android NDK unpacked into c:\android-ndk-r9d, and that you wish to use a gcc 4.8 toolchain.
Install Android NDK (duh!).
Install Cygwin -- make sure to include perl
Start Cygwin shell as an administrator to make sure native symlinks will work.
Within the console, run the following script to set the variables:
export \
CYGWIN=winsymlinks:native \
ANDROID_API=android-14 \
ANDROID_DEV=c:/android-ndk-r9d/platforms/android-14/arch-arm/usr \
PATH=/cygdrive/c/android-ndk-r9d/prebuilt/windows-x86_64/bin:/cygdrive/c/android-ndk-r9d/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64/bin:$PATH \
MACHINE=armv7 \
SYSTEM=android \
ARCH=arm \
CROSS_COMPILE=arm-linux-androideabi-
Now, unpack openssl:
tar xzfv openssl-1.0.1i.tar.gz (or whatever your tarball is)
cd openssl-1.0.1i (or whatever your version is)
Make sure you have actual native Win32 (!) symlinks in include/openssl:
cmd /c "dir include\openssl"
You should see something like:
13-Aug-14 05:59 PM <SYMLINK> aes.h [..\..\crypto\aes\aes.h]
13-Aug-14 05:59 PM <SYMLINK> asn1.h [..\..\crypto\asn1\asn1.h]
(etc.)
Now it's time to configure:
./config shared -no-ssl2 -no-ssl3 -no-comp -no-hw -no-engine --openssldir=/foo/bar
Ignore the failure to build (due to failure to find perl). We'll rectify this right away. Do this:
make PERL=$(cygpath -w $(which perl))
Now wait for a few minutes until it builds, and presto, you have your libcrypto.so etc.

Just a couple of comments on my experience with this:
Executing this statement:
PERL=$(cygpath -w $(which perl))
in the cygwin shell allows the shell to interpret the backslashes as escape characters and the build process chokes. To solve this I did the following:
$ echo $(cygpath -w $(which perl))
which produced the windows formatted path to the perl executable:
C:\cygwin64\bin\perl
Then I added this line to the export shown above:
PERL=c:/cygwin64/bin/perl \
There are other ways of doing this, but it worked and headed off the problem with the ./config statement documented above (not finding perl).
Second issue was the -no- statements. After running the configure, the script reports that you'll have to run make depend. I wanted to exclude MD5 (i.e. -no-md5) and when I did the make depend, it errored out with a report that MD5 was disabled. Uhhh, yes, that was kind of the idea, but I just won't use MD5 hashes. I did use the -no-ssl2 and didn't get any complaints after the make depend.
Third issue and this is a mystery. The build broke on compiling crypto because it could not find a symbol that is supposed to be defined in /crypto/objects/obj_xref.h. When I looked at the file, it was empty. Something in the perl script I suppose, but no time to debug right now, since I'm at proof of concept phase. I placed a copy from a patch that I picked up at https://github.com/devpack/openssl-android
After that, my build ran to completion. I've done no testing with this and it is not a trustworthy solution, but it did compile and produce the static libraries that I need for proof of concept for my client.
Just as an update, my shared library built with these libraries loaded fine on my target.

Cross Compiling libevent for Android

I'm stuck trying to cross-compile libevent to Android and I'd like to know what I'm doing wrong and get some assistance.
The version I'm trying to build is libevent-2.0.19-stable
I started following the steps described at http://warpedtimes.wordpress.com/2010/02/03/building-open-source-libraries-with-android-ndk/ and how to rewrite the Makefile into android.mk?
The Target Device is a Samsung Galaxy S2 running cyanogenMod 7
After several attempts, the best I did was by running the following steps:
1) Install android NDK and download libevent source code
2) Android NDK downloaded and running in ~/android-ndk/android-ndk-r8b
3) Execute:
export ANDROID_ROOT=~/android-ndk/android-ndk-r8b
export PATH=$PATH:$ANDROID_ROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/
You need to export the ABI for your device. armeabi-v7a is for devices with ARMv7 or above, any other device uses armeabi.
4) Execute ./configure with the appropriate parameters:
./configure \
--host=arm-linux-androideabi \
CC=arm-linux-androideabi-gcc \
LD=arm-linux-androideabi-ld \
CPPFLAGS="-I$ANDROID_ROOT/platforms/android-8/arch-arm/usr/include/" \
CFLAGS="-nostdlib" \
LDFLAGS="-Wl,-rpath-link=$ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib/ -L$ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib/" \
LIBS="-lc"
There was a warning in the meantime:
configure: WARNING: if you wanted to set the --build type, don't use --host.
If a cross compiler is detected then cross compile mode will be used
(I assume it's fine)
As it didn't recognise arm-linux-androideabi as a host, I got a new config.guess and config.sub from http://git.savannah.gnu.org/gitweb/?p=config.git;a=tree (indicated in the previous thread in Stack Overflow)
At this point, when building the source code running "make", it still crashes:
/home/narseo/android-ndk/android-ndk-r8b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/../lib/gcc/arm-linux-androideabi/4.4.3/../../../../arm-linux-androideabi/bin/ld: crtbegin_so.o: No such file: No such file or directory
collect2: ld returned 1 exit status
make[2]: *** [libevent.la] Error 1
make[2]: se sale del directorio «/home/narseo/libevent-source/libevent-2.0.19-stable»
make[1]: *** [all-recursive] Error 1
make[1]: se sale del directorio «/home/narseo/libevent-source/libevent-2.0.19-stable»
make: *** [all] Error 2
However, the file seems to be there:
~/android-ndk$ ls $ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib
crtbegin_dynamic.o libc.a libjnigraphics.so libstdc++.so
crtbegin_so.o libc.so liblog.so libthread_db.so
crtbegin_static.o libdl.so libm.a libz.so
crtend_android.o libGLESv1_CM.so libm.so
crtend_so.o libGLESv2.so libstdc++.a
Is there anything I'm doing wrong when running ./configure? Something else I didn't understand even looking at Android's NDK documentation was whether it was mandatory to create an Android.mk or if Makefile was sufficient
Any help will be very welcome!
Cheers
N
Note
This is how I managed to solve it in the end:
Initial PATH:
export ANDROID_ROOT=~/android-ndk/android-ndk-r8b
export PATH=$PATH:$ANDROID_ROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/
export PATH=$PATH:$ANDROID_ROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/include/
The errors seem to occur in the linking phase so as it cannot find crtend_so.o and crtbegin_so.o. Following crtbegin_so.o missing for android toolchain (custom build), we add a sym link to them in the source folder
cd source && ln -s $ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib/crtbegin_so.o
ln -s $ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib/crtend_so.o
The ./configure command:
./configure \
--host=arm-linux-androideabi \
CC=arm-linux-androideabi-gcc \
LD=arm-linux-androideabi-ld \
CPPFLAGS="-I$ANDROID_ROOT/platforms/android-8/arch-arm/usr/include/" \
CFLAGS="-nostdlib" \
LDFLAGS="-Wl,-rpath-link=$ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib/ -L$ANDROID_ROOT/platforms/android-8/arch-arm/usr/lib/" \
LIBS="-lc"
If it fails as it does not recognize system androideabi, try to get newer versions of config.sub and config.guess
It used to crash in the linking phase. Including -lgcc on the CFLAGS solved the issue.

This project builds libevent as a static library on Android here: https://github.com/ventureresearch/libevent
It includes the Android.mk and generated config files to build it cleanly.
Note that we are building it for inclusion into an Android device image, and NOT building through the NDK. It would probably still be a good place to start.

Try this
./configure --host=arm-linux-androideabi CC="$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc --sysroot=$SYSROOT" CFLAGS='-march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16'
It works for me.

Try with below configurations:
ANDROID_SYSROOT=$ANDROID_ROOT/platforms/android-8/arch-arm/
./configure --host=arm-linux-androideabi CFLAGS=--sysroot=$ANDROID_SYSROOT LDFLAGS=--sysroot=$ANDROID_SYSROOT

How to configure gcc to compile for android?

I've read in the gcc documentation that it supports building android binaries with the -mandroid and -mbionic switches. First I tried it with the native gcc built from svn. Result:
dancsi#dancsi-VirtualBox:~$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/i686-pc-linux-gnu/4.7.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../source/configure --enable-threads --disable-nls
Thread model: posix
gcc version 4.7.0 20110611 (experimental) (GCC)
dancsi#dancsi-VirtualBox:~$ g++ test.cpp -mandroid -o test.out
dancsi#dancsi-VirtualBox:~$ file test.out
test.out: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, not stripped
Basically, it failed. Next, I tried to compile the same gcc sources with target=arm-linux-androideabi, (without defining sysroot,...), and it passed the configuration, but failed to build saying pthread.h is not found:
In file included from ../.././gcc/gthr-default.h:1:0,
from ../../../combined/libgcc/../gcc/gthr.h:160,
from ../../../combined/libgcc/../gcc/unwind-dw2.c:37:
../../../combined/libgcc/../gcc/gthr-posix.h:41:21: fatal error: pthread.h: No such file or directory
compilation terminated.
So, does anybody have the instructions for how to use gcc to build android binaries (I don't want to use code sourcery or android-ndk)?
EDIT:
my configure options
configure --target=arm-linux-android --host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-libssp --disable-libgomp --disable-nls --enable-languages=c,c++,java

I had exactly the same problem as described by dancsi while trying to compile my own cross compilation tool chains for Android (I wanted to build a 32 bit variant of them so I don't need to buy a 64 bit PC or do my android stuff in a VM).
I am using the tool chain sources from the official AOSP tool chain repo:
repo init -u https://android.googlesource.com/toolchain/manifest
The solution is to use the following 2 extra configure options: --with-headers and --with-libs. I've got this solution by reading the following file: [android-toolchain-repo]/build/README:
The other way is to specify the headers and libraries with --with-headers and
--with-libs separately. If you configure your tree with a prefix. The headers
and libraries will be copied to the install directory specified by the prefix.
For the values of those 2 extra parameters I used [android-src-repo]/prebuilts/ndk/8/platforms/android-14/arch-arm/usr/lib and [android-src-repo]/prebuilts/ndk/8/platforms/android-14/arch-arm/usr/include. [android-src-repo] is referring to my repo checkout of the base AOSP sources (in my case I am on the android-4.2.2_r1 branch of it).
The end-result of the two configure statements I need are the following:
./configure --target=arm-eabi --host=i686-linux-gnu --build=i686-linux-gnu --disable-gold \
--with-gcc-version=4.6 --with-binutils-version=2.21 --with-gmp-version=4.2.4 --with-mpfr-version=2.4.1 \
--with-gdb-version=7.3.x --with-gold-version=2.21 --prefix=/tmp/toolchain --disable-multilib \
--with-libs=/home/boeboe/android-src/prebuilts/ndk/8/platforms/android-14/arch-arm/usr/lib \
--with-headers=/home/boeboe/android-src/prebuilts/ndk/8/platforms/android-14/arch-arm/usr/include \
--program-transform-name='s&^&arm-eabi-&' --with-arch=armv5te --disable-option-checking
./configure --target=arm-linux-androideabi --host=i686-linux-gnu --build=i686-linux-gnu --enable-gold \
--with-gcc-version=4.6 --with-binutils-version=2.21 --with-gmp-version=4.2.4 --with-mpfr-version=2.4.1 \
--with-gdb-version=7.3.x --with-gold-version=2.21 --prefix=/tmp/toolchain \
--with-libs=/home/boeboe/android-src/prebuilts/ndk/8/platforms/android-14/arch-arm/usr/lib \
--with-headers=/home/boeboe/android-src/prebuilts/ndk/8/platforms/android-14/arch-arm/usr/include \
--program-transform-name='s&^&arm-linux-androideabi-&' --disable-option-checking
Notice the extra --disable-option-checking argument which was necessary for configure to accept all arguments!
This long list of arguments was constructed by checking the original configure arguments passed for the default 64 bit version of the 4.6 gcc toolchain. This can be checked in the SOURCES files available in [android-src-repo]/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6 and [android-src-repo]/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.6.
In the same files, git tags can be found, so I also checkout those specific version in my [android-toolchain-repo]. For the extra modules needed by gcc, like gmp/mpfr/gdb..., I extracted the correct versions of the tar-balls available in [android-toolchain-repo]/gmp|mpfr|gdb. This was the easiest way I could find out, for my original configure statement to be able to pick up those modules.
The same technique as described above also allowed me to compile a 32 bit variant of the latest gcc 4.7 tool chain (currently being used on the MAIN branch of AOSP). The configure options were of course different in this case.

In file included from ../.././gcc/gthr-default.h:1:0,
from /mnt/network/source/gcc/libgcc/../gcc/gthr.h:160,
from /mnt/network/source/gcc/libgcc/../gcc/unwind-dw2.c:37:
/mnt/network/source/gcc/libgcc/../gcc/gthr-posix.h:41:21: fatal error: pthread.h: No such file or directory
compilation terminated.
make[2]: *** [unwind-dw2.o] Error 1
make[1]: *** [all-target-libgcc] Error 2
make: *** [all] Error 2
I'm getting the same error as you, but I'm not compiling for Android. I'm trying to build w64-mingw32 compiler.
AR=x86_64-w64-mingw32-ar RANLIB=x86_64-w64-mingw32-ranlib
../gcc-4.5.1/configure --prefix=/tools \
--with-local-prefix=/tools --enable-clocale=gnu \
--enable-shared --enable-threads=posix \
--enable-__cxa_atexit --enable-languages=c,c++ \
--disable-libstdcxx-pch --disable-multilib \
--disable-bootstrap --disable-libgomp \
--without-ppl --without-cloog --build=$MACHTYPE --host=$MACHTYPE --target=x86_64-w64-mingw32
My response is so you know its not just Android, the trouble is more general then just building for the ARM architecture.
I think its a c++ issue, cause I had/have no trouble with building a c compiler alone.