There are set of related questions here, because I suspect I am asking the wrong question. The related questions may help someone discern what my fundamental misunderstanding is.
I have worked through:
https://www.yoctoproject.org/docs/2.6/ref-manual/ref-manual.html
https://www.yoctoproject.org/docs/2.6/dev-manual/dev-manual.html
https://www.yoctoproject.org/docs/2.6/sdk-manual/sdk-manual.html
I'm looking for an single build environment from which I can use bitbake, and build a product for different target architectures.
This after all seems to be what the Yocto/OE holy grail is.
It seems like the most functional x86_64 environment is had from:
git clone git://git.yoctoproject.org/poky
It is more capable than the SDK's, but how do I cross-build this environment for another platform?
Is there an SDK that is as functional as this git clone'd environment? Meaning it has a working bitbake and I can cross-build bootable images for different targets?
Questions:
Why can't an SDK build an SDK? (e.g. http://downloads.yoctoproject.org/releases/yocto/yocto-2.6/buildtools/)
Why doesn't an SDK even include bitbake? (The ext SDK does, but doesn't like to add it to the path).
Why does an extensible SDK with properly sourced env (and bitbake added to the path) seem to prefer the distro-installed build tools instead of the ones in the SDK? (when using bitmake directly instead of devtool)
Why is an SDK apparently tied to build for a particular machine or architecture, and apparently unable to cross-build for different architectures? The process for building an SDK even wishes the final architecture to be specified in advance
What I'm used to is a build-sysroot with the cross-toolchain running under some sort of pseudo/proot/chroot with my sources mounted into it.
I realise that Yocto/bitbake does this under the hood, all the recipe caching seems great, the git clone checkout seems powerful, the devtool workflow seems great, but then it all falls down when I try to standardise generation of this environment, or make it cross-compile.
(I’m expecting to source the environment file from a target directory containing some local conf files to specialise the build, and then use bitbake to make the build)
What have I missed? - thanks for reading this far ;-)
SDK is such a generic word that in the context of yocto, it can be miss interpreted and so your question is legit.
Yocto is a wonderful tool to build completely custom images and can be adjusted at all level (bootloader, kernel, applications) based on source fetched online.
The SDK you can generate with yocto is as quoted from the documentation:
The Standard SDK provides a cross-development toolchain and libraries
tailored to the contents of a specific image.
Based on my small experience with Yocto, you use meta layers to create and customize your environment. When your environment is setup, you can generate an SDK to easily cross compile your aplicative programs for your target machine.
Yocto tool is way too powerful, heavy and complicated for developers who just focus on the aplicative part of a project. The SDK on the other side is perfect for that use but you can't change anything in the toolchain with it, you can only use it. If a bug or a patch needs to be applied in runtime libs for example, you need to regenerate the SDK and give this new versions to developers.
With that short explanations:
It is more capable than the SDK's, but how do I cross-build this
environment for another platform?
You need to customize your Yocto meta layers to change from a platform to another.
Is there an SDK that is as functional as this git clone'd environment?
Meaning it has a working bitbake and I can cross-build bootable images
for different targets?
No, i don't think so
Why can't an SDK build an SDK?
Because that's not the philosophy of the SDK, sdk is a generated toolchain for a specific image to cross compile your programs, no more.
Why doesn't an SDK even include bitbake?
Bitbake is a tool to parse yocto recipe (so meta layers) and so, there is no need to have this tool in the SDK
Why is an SDK apparently tied to build for a particular machine or
architecture, and apparently unable to cross-build for different
architectures? The process for building an SDK even wishes the final
architecture to be specified in advance
I think i already gave an answer to this question but, about the second part of your question. It is possible to be a little bit agile and start both the BSP and applications in parallel. Every week, you release a new SDK with BSP new changes an the toolchain is always up-to-date for developers (This is a very idealistic vision i admit)
Reading from https://www.yoctoproject.org/docs/2.6.1/ref-manual/ref-manual.html#cross-development-toolchain
it seems that an SDK and eSDK are examples of a relocatable toolchain;
A relocatable toolchain used outside of BitBake by developers when
developing applications that will run on a targeted device.
This sentence particularly gives the game away:
You can also find more information on using the relocatable toolchain
in the Yocto Project Application Development and the Extensible
Software Development Kit (eSDK) manual.
SO I guess the git-clone-poky checkout which builds the SDK and eSDK is:
A toolchain only used by and within BitBake when building an image for a target architecture
No doubt I am interested in:
toolchain concepts as they apply to the Yocto Project
and should:
see the "Cross-Development Toolchain Generation" section in the Yocto
Project Overview and Concepts Manual https://www.yoctoproject.org/docs/2.6.1/overview-manual/overview-manual.html#cross-development-toolchain-generation
Certainly the first image makes it clear that the SDK is for building apps, not the image. I want to build the image (which of course may contain apps).
And so I may wish to make an SDK for other app builders, and incorporate their app into my sources and do the final build for them.
It may also be that the toolchain used for building an image can be run within the SDK so as to use the toolchain of the SDK rather than the host linux distro toolchain no, you can't
Following the instructions on the PlayN wiki I was able to get the "hello" PlayN sample running on the iOS simulator. However, when using MonoStudio, I was told that I need to upgrade to an Indie license or higher to compile the code. (Apparently I was using 33+ features which required it.) When I activated a trial edition, the sample compiled and ran fine on the simulator.
The PlayN wiki seems to indicate the you'd only need a license if you plan on testing on a real device. Is it wrong or am I missing something?
Also, I thought the idea behind PlayN was to build a free, open source game engine on top of free, open-source technology. Mono is both, but MonoTouch is neither. Is there another option or am I stuck with shelling out $1000/year to use iOS (which so far seems far from fully implemented on the PlayN side of things)?
Right now, there isn't. Sorry its disappointing, but its the nature of iOS. Its a very non-free platform.
Perhaps you can try your hands at writing a cross compiler, and release it under an opensource license? You can try basing it on http://gcc.gnu.org/java/.
Is there any migration analysers available for MonoTouch ?
I have seen one for Mono, but not for MonoTouch.
Short answer: No, there is none at the moment.
Long answer
The situation is a bit different from Mono. In general you test a complete and compiled (against a specific version of the framework) .NET application with MoMA, to get a report of what pieces are missing (or incomplete) in Mono that could affect the execution of your application on other platforms (e.g. OSX and Linux).
Testing a complete applications for MonoTouch would reports tons of issues - since the UI toolkit is totally different. E.g. anything about System.Windows.Forms, WPF... would always missing.
However if your assemblies are already split into (something like) an MVC design it would be possible to test some (the non-UI parts) of them against definitions based on the MonoTouch base class library.
Finally if someone has an immediate need (or looking for a nice project) MoMA is available as open source and the evaluation versions of MonoTouch contains all the assemblies needed to build the definitions files. A bit of extra filtering could make this into a very nice tool.
Alternative
You can see a list of the assemblies that are part of MonoTouch and some platform restrictions (compared to .NET) you should be aware.
In Xcode 4.3, now you can enable using LLDB as the debugger for iOS targets.
What advantages does it have over using the good old GDB? GDB still works with LLVM and I cannot see any obvious differences in "everyday" debugging tasks.
The most notable advantage is that LLDB understands dot syntax in properties:
po self.property
A quote from LLVM project blog:
LLDB supports basic command line debugging scenarios on the Mac, is scriptable, and has great support for multithreaded debugging. LLDB is already much faster than GDB when debugging large programs, and has the promise to provide a much better user experience (particularly for C++ programmers). We are excited to see the new platforms, new features, and enhancements that the broader LLVM community is interested in.
Another quote from LLDB homepage:
LLDB is a next generation, high-performance debugger. It is built as a set of reusable components which highly leverage existing libraries in the larger LLVM Project, such as the Clang expression parser and LLVM disassembler.
Why a new debugger
In order to achieve our goals we decided to start with a fresh architecture that would support modern multi-threaded programs, handle debugging symbols in an efficient manner, use compiler based code knowledge and have plug-in support for functionality and extensions. Additionally we want the debugger capabilities to be available to other analysis tools, be they scripts or compiled programs, without requiring them to be GPL.
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 9 years ago.
Improve this question
I am curious about what tools are used to build the next version of themselves.
For example, Delphi has long claimed that "Delphi is written in Delphi".
I assume Visual Studio is written using Visual Studio.
What are some other examples of tools that written in themselves?
Interestingly, the VB.NET & C# compilers themselves are written in unmanaged C++ (leading to the C++ team's T-Shirt: "My compiler compiled yours"). The C# team hopes to have a fully managed-C# hosted C# compiler for VS2010.
Bjarne Stroustrup mentioned in The Design and Evolution of C++ that the first C++ compiler was written in C++.
I've just noticed this is also a question in his FAQ:
The first C++ compiler (Cfront) was
written in C++. To build that, I first
used C to write a "C with
Classes"-to-C preprocessor. "C with
Classes" was a C dialect that became
the immediate ancestor to C++. That
preprocessor translated "C with
Classes" constructs (such as classes
and constructors) into C. It was a
traditional preprocessor that didn't
understand all of the language, left
most of the type checking for the C
compiler to do, and translated
individual constructs without complete
knowledge. I then wrote the first
version of Cfront in "C with Classes".
This is off-topic, but strictly speaking, it is an example of a tool which builds itself.
The reprap - an open-source 3d prototyping machine, which recently gave 'birth' to "its first complete working replicated copy".
I love this kind of stuff.
Generically speaking, C compilers are usually written in C... *nix kernels are compiled on *nix, etc.
Also, there's the pypy project which provides a Python interpreter written in Python.
When gcc (the Gnu C compiler http://gcc.gnu.org/) was not available widely, you had to compile it from source, compiling stage1 compiler, then compile stage2 with stage1, till you have your final compiler. I assume it must be the same today.
Here is another example: Mono's C# compiler is self hosting - i.e. it's written in C# and used to compile itself.
Dog fooding refers to the more general practice of a company using its own product internally, especially during its development.
Lots of folks like to look at how Lisp can be implemented in Lisp.
Squeak is a Smalltalk-80 implementation written in itself.
even its virtual machine is written entirely in Smalltalk making it easy to debug, analyze, and change.
Sun's Java compiler has long been written in Java. However, recent work is writing a JIT compiler in Java as well. This is the JVM component that converts Java byte code to native processor instructions.
We use to develop using RealBasic. The IDE is written in itself, or so I've been lead to believe.
ghc, the Haskell compiler, is mostly written in Haskell.
tcc is another self-hosting C compiler for x86 and ARM. Its claim to fame is being, well, tiny (100k or so for preprocessor, compiler, assembler, and linker).
I would assume that pretty much any tool that's part of the typical development process would be involved in its own development, to whatever extent possible. This includes:
certain programming languages, especially compiled ones
IDEs
text editors
version control systems
bug trackers
build systems
If you're on a team building one of these tools, and you're not developing it for a specific niche that doesn't apply to your team, I don't know why you wouldn't use it to build itself. Having developers be users of the product is one of the best ways to find possible improvements.
For the AmigaOS there was a third party Basic interpreter (don't remember the name) for which you could later buy a compiler. The compiler was delivered as source, so you had to use the interpreter to run the compiler to compile itself...
To cite Kent Beck:
...it may seem a bit like performing brain surgery on yourself.
Visual Studio and Team Foundation Server build themselves. It's called dogfooding, a term which if not originating in Microsoft, it certainly likes
Oracle Application Express is a web application development tool that is built in itself.
Eclipse IDE is generally built and developed using Eclipse IDE.
It is fairly typical to have a languages compiler written in its own language. This is called self-hosting or bootstrapping.
Maven2 is built using Maven2.
Ok, it's not built (i.e. written) using itself, as it is a tool to build (i.e. compile) project, but it is using its own code to compile...
I was amazed with JSLint
In short it has been described as Javascript "compiler" using javascript.
I am building an IDE-based code generator, and I am using it to build itself. If fact, as Stroustrup did, I am first building a valid generator model and using a pre-processor to build the final C++ code to compile. Once I have a good working version of the IDE, I'll start using it to build further versions of itself.
It's like giving a new dimension to the meaning of "recursive programming"!
AFAIK does the OpenJDK build itself first with the installed java and afterwards with itself.
Naturally the Jetbrains team uses its own IDE IntelliJ IDEA to develop this IDE.
I assume this is true for most IDE vendors.
As far as I know, when building EMACS from source, all of the ELISP code is bootstrapped. I found that quite noteworthy.
Not quite what you're asking for, but the entire development environment for Revolution http://www.runrev.com is built using Revolution itself, and the source (except for small parts that enforce the license) is completely exposed in source form. So if you don't like the way the dev environment is implemented, you can change it. Find a bug, fix it. You can also easily build additional development tools and integrate them.
Ada and Forth
I gave the Smalltalk-80 answer an uptick. Best, most elegant example I can think of. The question also reminds me of a slightly related problem that used to be popular: write a program that outputs itself. Not the same level of bootstrapping, but a fun little programming puzzle for your amusement. Maybe not possible in all languages?
The old Watcom C/C++ compiler was built using itself.
Kragen Sitaker's Ur-Scheme is a fine example of a small nontrivial compiler written in itself. That page links to several more good sources in that vein.