I am working on an AMD64 machine and I need to use libraries provided in an SDK that are .so files compiled for ARM64. The SDK also contains tools to cross-compile for ARM64 on AMD64 machines. I have access to a blank ARM64 machine.
What are some general approaches for running libraries like this on an AMD64 machine? I want to be able to run all the code locally. Is this even possible?
For reference, the SDK is something like the Yocto Project's SDK. Do I need something like the QEMU emulator as referenced?
Related
I'm running Centos 7 and am trying to build hipSYCL (see here)
The issue is that hipSYCL needs to have cmake info from the LLVM build (via the LLVM_DIR cmake variable).
This is problematic for me because building LLVM requires a massive 35Gb for the libraries and exes. I don't have that much memory to spare.
I did find a build of llvm-toolset-8.0 online for Centos 7 and installed it, but to my surprise, that didn't seem to work with LLVM_DIR because there's no cmake files (since I didn't build it locally).
So, my question would be, is there a way to build hipSYCL using pre-built LLVM-clang?
If I'm missing or misunderstanding something, I'd appreciate any help.
LLVM publishes the necessary cmake files, and the binary OS packages I've seen include it, generally in a directory called /usr/lib/llvm*/lib/cmake and in a package called something like llvm-*-dev.
I got a C++ project for Bazel, which by default builds for 64-bit Windows on my machine. However, I want to create a 32-bit executable, which, according to the documentation, is supported.
I have tried these commands:
bazel build :knusperli --platforms #bazel_tools//platforms:x86_32
Target #bazel_tools//platforms:x86_32 was referenced as a platform, but does not provide PlatformInfo
bazel build :knusperli --cpu i386_windows
ERROR: No toolchain found for cpu 'i386_windows'.
I thought, since Visual Studio can build 32-bit executables, it would be easy in Bazel as well, but I can't find any information on how to actually do this.
Bazel does not support building 32-bit binaries out-of-the-box. It's possible to add support via a custom CROSSTOOL file.
See:
https://github.com/bazelbuild/bazel/wiki/About-the-CROSSTOOL
https://github.com/bazelbuild/bazel/wiki/Building-with-a-custom-toolchain
https://github.com/bazelbuild/bazel/wiki/Yet-Another-CROSSTOOL-Writing-Tutorial
I'm making an application that uses libimobiledevice and is cross-platform(Mac, Windows, and Linux). I don't have access to all the platforms so I can't compile it myself, and it's a pain to do so.
Are there pre-compiled versions of libimobiledevice for each platform that I can distribute with my application so the user doesn't have to install it manually?
It's relatively easy to provide a binary distribution of libimobiledevice for Windows and macOS.
For Windows and macOS, you can download pre-compiled versions of libimobiledevice at https://github.com/libimobiledevice-win32/imobiledevice-net (see the releases page). Admittedly, the repository name is a bit off. It does provide Windows and macOS binaries for libimobiledevice, and you don't have to use .NET if you just want to use the binaries.
The binaries are published via the Azure Pipelines build system, so you would fetch them at https://dev.azure.com/libimobiledevice-win32/imobiledevice-net/_build, or newer builds as they become available.
On Linux, it's a different story, because the various Linux distributions come with different versions of some of the dependencies of libimobiledevice (such as OpenSSL). You'll need a different binary package for most distributions of Linux.
There's a PPA you can use, https://launchpad.net/~quamotion/+archive/ubuntu/ppa, which provides compiled versions of libimobiledevice for Ubuntu 14.04, 16.04 and 18.04.
Most Linux distributions also include a libimobiledevice package, but that may be outdated - be aware.
I have some existing source code that is written in C that I want to build and include in my iOS project. The entire source package is very large and is built using existing Makefiles and GCC. It is producing static libraries (.a files) that I would love to move over to my iOS project. However, the static libraries the Makefile produces is for x86 processors, which obviously won't work on iOS.
Is there a way I can switch GCC to build for ARMv7/ARM64 instead, without making changes to the existing source (in most cases)? I know there is the -march switch for GCC or you can download ARM specific GCC compilers, so I know the general concept of building for a different architecture than the build machine.
To build for ARM on Mac OS, will I have to download a different GCC compiler or is that capability built into the default GCC?
I'm sorry for the lack of understanding of basic concepts here; I'm primarily a Java and Objective-C developer, so building source for different architectures is a mostly foreign concept to me.
Whilst GCC supports a good many CPU architecture and platforms, it is usually built for a single one. To compile for ARM you generally need an ARM-cross-compiling GCC targeted appropriately.
The default system compiler for MacOSX and iOS for all architectures is clang and has been for some time (the last version of GCC apple shipped in dev tools is creaking and obsolete, and definitely won't support ARMv8).
The usual way of getting clang is to install Xcode (free from the App Store). There's a option in the installer (and in the UI of Xcode) to install the command-line tool package. This installs sym-links in /usr/bin to the compiler, and installs a bunch of other stuff you might expect such as make.
clang is (mostly) command-line compatible with gcc, and furthermore, you'll find that if you run gcc from the command-line on a Mac with dev-tools installed, you in fact get clang.
$ gcc --version
Configured with: -- prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/usr/include/c++/4.2.1
Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin14.0.0
Thread model: posix
clang comes with ARMv7, ARMv8, i686, x86_64 on MacOSX, and can be configured to compile for any of these from the command line (See documentation)
Given the above, there's a fair chance your code will compile with minimal changes to compiler-flags using the existing makefile. You might want to read the documentation for lipo - which allows you to produce multi-architecture binaries.
I am using open source C++ library DCMTK from http://dicom.offis.de/dcmtk.php.en.
I have successfully compiled this library on Windows using VC++ IDE, MacOS Xcode, Mac iOS simulator.
But I am not able to compile this library on iOS device as it is ARM based architecture.
DCMTK library compiled very well on Intel architecture.
Now my problem statement is :-
I need to compile this DCMTK C++ library on ARM architecture by cross compilation.
I am using Ubuntu 64 bit machine for cross compilation.
I have installed binaries from GNU ARM tool chain from http://www.gnuarm.com/
I am using GCC toolchain 4.0 binutils-2.16.1, gcc-4.0.2-c-c++, newlib-1.14.0, insight-6.4, TAR BZ2 [65.5MB] binaries for Ubuntu 64 bit machine for ARM cross compilation.
After Installing these binaries on Ubuntu I have set PATH environment variable to
PATH=$PATH/gnu_arm/bin
For configuring the DCMTK C++ library I have run the following command on shell
CC=arm-elf-gcc CXX=arm-elf-g++ AR=arm-elf-ar RANLIB=arm-elf-ranlib ARFLAGS=cruv ./configure –prefix=$home_dicom –target=arm-elf –host=arm-elf –enable-std-includes –disable-threads
It creates a make file properly. Now I am trying to compile the code by using make command, but facing so many compilation errors like :-
1) I tried to compile my first dependent C++ library that is ofstd.
I got error for DIR*, struct dirent, opendir(), closedir() calls.
It includes for these calls, but I did not found any definitions for the above calls in this header file.
2) When I compile another library oflog I got the following errors like
error: nthos was not declared in this scope
error: ntohl was not declared in this scope
error: htons was not declared in this scope
error: htonl was not declared in this scope.
These calls are networking calls and are not defined in any of the header file from GNU ARM tool.
I tried to download the sources of ARM binaries and extracted the tar files and try to copy missing header files to installed GNU ARM on Ubuntu.
For some files it compiles after doing changes to copied header files, and for some again it gives compilation errors.. There is a loop of compilation errors for every file present under DCMTK library as some of the standard header files are missing.
Please suggest if there is any other tool chain available for ARM cross compilation on Ubuntu 64 bit machine.
Or any other good solution apart from this.
Thanks!!!
Amit
There are many areas for problems when it comes to cross compiling. There are three main flags for cross compiling. -host , -target, and -build. The -host flash is the machine in which the resulting binaries will run on. The -build flash is the system in which you will be compiling on. The -target flag is for building libraries that will be used in cross compiling. So if you were to build your own gcc tool chain. So in your case you won't set the target flag as we're not building a tool chain. the -host flag will be arm-elf. And the -build flag will be amd64.
Usually a cross compilation fails if there are inconsistencies between the regular c compiler and the cross compiler. I have compiled several libraries for the avr32 with a toolchain generated by buildroot, but in some cases (socat project for example) it hasn't been possible.
Your host, your target and the CXX flags look ok. I think it is not necessary to put the AR flag (that is the idea with the host and target option).
In other hand, this is an example for the expat libraries for the avr32:
./configure --host=avr32-linux --prefix=/home/juan/builds/build_expat/ CC=avr32-linux-gcc
make; make install
I can recommend you that tries to cross compile from an ia32 architecture. I had several problems with that ubuntu in the past.