CODEWITHSUNDEEP
macosgcccross-compilingtoolchainarmv6
Trcx
Trcx

Reputation: 4444

Cross compile for iPhone on a mac?

How would I go about setting everything up to cross compile from my OSX 10.7 Macbook pro to my jailbroken 4th generation iPod touch. I'm mainly aiming to be able to port open source libraries to iphone. I can't seem to find any good/recent articles on cross compiling for iOS 4.

Upvotes: 4

Views: 3890

Answers (2)

LeoTh3o
LeoTh3o

Reputation: 137

After some attempt, I found out that it's possible to use ./configure and force it to build for arm-apple-darwin11. You have to use these flags directly after the ./configure --some-flags:

CPP="cpp" CXXCPP="cpp" 
CXX="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-llvm-g++-4.2" CXXFLAGS="-O -arch armv6 -arch armv7 -isysroot $SDK_ROOT/SDKs/iPhoneOS5.0.sdk" 
CC="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-llvm-gcc-4.2" CFLAGS="-O -arch armv6 -arch armv7 -isysroot $SDK_ROOT/SDKs/iPhoneOS5.0.sdk" 
AR="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/ar" 
AS="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/as" 
LD="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/ld"
LDFLAGS="-lstdc++ -arch armv6 -arch armv7 -isysroot $SDK_ROOT/SDKs/iPhoneOS5.0.sdk"
LIBTOOL="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/libtool"
STRIP="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/strip" 
RANLIB="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/ranlib"

CPP and CXXCPP are the preprocessor required (the default one); CC and CXX are the path to the c and c++ compiler for arm that comes with Xcode, the other are flags the compiler gets or macros that defines the path to the most common tools used when compiling. I cannot grant everything will work, but this is a good idea of what you should do. I'd suggest to add to ./configure these flags:

--prefix=/tmp/build --host=arm-apple-darwin11

what they do is to help create a makefile that will send libs and programs in a folder under /tmp/build.

Upvotes: 4

LeoTh3o
LeoTh3o

Reputation: 137

Neither did I. All the toolchain I tried ended up in not working or creating x86_64 binaries, which won't work on iOS. I'm currently trying to build apr directly on my iPad as I have installed from Cydia all the required things, yet I'm stuck kqueue.c not compiling properly. I have already ported lua and some other software, so I can say it generally works this way. The main reason for building on a native platform rather than cross compiling is that some programs rely on other programs (example: apr-util on apr) so some of them must be run. However, it's not possible to run arm on intel (at least without emulation, and iPhone Simulator uses i386 binaries).

Anyone who's interested in using/building UNIX tools on iOS has to keep these points in mind:

  • You might find what you wanted, but it's not said it'll work as expected (this is intended especially for developers. Example: apr is shipped in Cydia, but it's not a complete package, so it's useless to build apr-util).
  • You have to use a jailbroken device. This may become a problem if you break the OS and need to restore. Be always sure to save SHSH so that you're able to restore to a jailbreakable iOS.
  • If you don't find what you were searching, things will get pretty messy. Most software, although thought to work on generic UNIX system, might have problems on iOS, which is near OS X in structure and way to work, but has differences especially under the net-related sections. Plus you'll probably have to (fake)code sign any software you build.
  • Even software without build problems may hold unwanted surprises: I had successfully build apache2 for iOS, but when I run I got stuck with SIGSYS, without much more explanation.

So, beware and brace yourself, because things are not easy usually.

About the fact of Mac being without a toolchain (except the one provided by Apple), this may hold an explanation as you don't need to have a mac to download Xcode, while a mac cost usually more than devs are willing to spend. This means there aren't much people doing the same thing you do, despite the boom mac hardware has had recently. Toolchains have been more or less successfully built for Linux based OSes, such as Ubuntu. You can always try to use a VM.

Upvotes: 2

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