Mono can be compiled to native AOT executable using mkbundle.
My question is, how is the garbage collection works? If I compile Mono into AOT executable, should I make modification in the codes, to release unused variables / objects ?
Roughly speaking, after AOT compilation your application no longer needs JIT at runtime, but you still get GC and almost everything CLR offers except some part of reflection (Emit related).
Limitations are documented in http://www.mono-project.com/AOT
You don't need to modify your code generally except you need to remove anything that AOT does not support.
References:
http://tirania.org/blog/archive/2006/Aug-17.html
http://tirania.org/blog/archive/2008/Nov-05.html
Miguel has other posts on AOT details too.
Related
I am totally new to CMake and compiled languages for that matter. I have seen this question and answer. But I still don't fully understand what CMake is.
I am coming from a nodeJs/Javascipt environment, therefore if I could know a CMake equivalent in the nodeJs/Javascipt environment it would really help me understand what it is.So... Is CMake an equivalent of npm?
No, citing from Wikipedia:
CMake is a cross-platform free and open-source software tool for managing the build process of software using a compiler-independent method. It supports directory hierarchies and applications that depend on multiple libraries. It is used in conjunction with native build environments such as Make, Qt Creator, Ninja, Apple's Xcode, and Microsoft Visual Studio. It has minimal dependencies, requiring only a C++ compiler on its own build system.
JavaScript is an interpreted language, that means NodeJS/Browsers read and understand the code and execute it directly. For example C is built via a compiler (that reads and understands the code before execution) to Machine code (that does not need to be understand because it's the native language from your processor) and can be executed faster. CMake simplifies calling the Compiler, linking libraries (something like setting up require) and more for all files. Altough sometimes using babel, webpack and others via npm run is called 'building'.
I'm creating a modular open-source library. Let's say the project has 15 .m files in it.
Should I (1) release it like the Venmo iOS SDK (Cocoa Touch Static Library) or (2) release it like JSONKit (just the source code)?
Releasing as source code means you, and your developers, don't have problems when a new architecture comes out. A static library built as armv6 wouldn't work with the latest Xcode today.
One caveat with source code releases, since you don't know what build settings the project it's added to will have, you'll need to do extra work to make sure it builds without warnings as best you can, even for pedantic warnings.
I prefer frameworks over static libs. Its easier to ship resources in the framework bundle if you eventually need to and there no cost to dynamic linking. If its pure C and the libraries dependencies are guaranteed to be there then it might be ok. But in general I try to avoid static linking unless I know the target OS has the exact dependencies for that binary at deployment time.
Its much easier to load a dynamic library with the endpoints you need at runtime (which were compiled for that exact platform but have the same external interface) than it is to fail with a static lib that was compiled directly to external dependencies which dont exist on the target platform.
Maybe Im crazy but this is what Ive always done in C, C++ or obj C. Just my opinion.
http://en.wikipedia.org/wiki/Static_library
I have been researching Golang and I see that it has a compiler.
But is it compiling Go into assembly level code or just converting it into BYTECODES and then calling that compilation? I mean, even in PHP we are able to convert it into BYTECODES and have faster performance.
Is Golang a REPLACEMENT for system level programming and compiling ?
This is really a compiler (in fact it embbeds 2 compilers) and it makes totally self sufficient executables. You don't need any supplementary library or any kind of runtime to execute it on your server. You just have to have it compiled for your target computer architecture.
From the documentation :
There are two official Go compiler tool chains. This document focuses
on the gc Go compiler and tools (6g, 8g etc.). For information on how
to work on gccgo, a more traditional compiler using the GCC back end,
see Setting up and using gccgo.
The Go compilers support three instruction sets. There are important
differences in the quality of the compilers for the different
architectures.
amd64 (a.k.a. x86-64); 6g,6l,6c,6a
A mature implementation. The
compiler has an effective optimizer (registerizer) and generates good
code (although gccgo can do noticeably better sometimes).
386 (a.k.a. x86 or x86-32); 8g,8l,8c,8a
Comparable to the amd64 port.
arm (a.k.a. ARM); 5g,5l,5c,5a
Supports only Linux binaries. Less widely used than
the other ports and therefore not as thoroughly tested.
Except for
things like low-level operating system interface code, the run-time
support is the same in all ports and includes a mark-and-sweep garbage
collector, efficient array and string slicing, and support for
efficient goroutines, such as stacks that grow and shrink on demand.
The compilers can target the FreeBSD, Linux, NetBSD, OpenBSD, OS X
(Darwin), and Windows operating systems. The full set of supported
combinations is listed in the discussion of environment variables
below.
On a server you'll usually target the amd64 platform.
Note that Go is well known for the speed of compilation. When deploying my server programs, I don't build for the different platforms on the development computer : I deploy the sources and I compile directly on the production servers. Since Go1 I never had a code compiling on one platform and not compiling on the other ones.
On Windows I had no problem in making an exe on my development computer and simply sending this exe to people never having installed anything Go related.
Go compiles quickly to machine code yet has the convenience of garbage collection and the power of run-time reflection. It's a fast, statically typed, compiled language that feels like a dynamically typed, interpreted language.
Source - golang.org
Golang is a compiler-based language, it can easily be compiled on the development computer for any targeted system such as linux and mac.
A golang project when have compiled turns to a self-sufficient executable and can be ran on the targeted system without anything additional. It's because the golang compiler turns your code into bytes ready to execute on a system which can run compiled c code.
Mono has a LLVM compiler. Is there anyway to use it with Emscripten (compile C# code to JavaScript)?
There is currently no out of the box way to do this. It might be possible, but it would require a lot of work. You would need to run mono in full AOT (ahead of time) compilation mode with the LLVM codegen. But there are many issues:
LLVM is currently not used for all methods, and mono falls back to it's own code generator in a number of cases. You would either need to get the LLVM suport working for all cases, or provide the JS code needed when LLVM cannot be used.
Mono currently has a number of architecture specific files (x86, amd64, arm, etc) and would probably need equivalent for JS, both for the code generation and for the AOT runtime.
And so on...
you can try to use C# Native
have a look here http://csnative.codeplex.com
Even if you run mono in full AOT and compile your program with LLVM it is not possible to use it with emscripten. This is quote from my discussion in mono group:
Besides that, no, it's not possible to use emscripten with mono's llvm output for a lot of reasons.
The output embeds calls to the mono runtime and some trampilines.
Mono use a custom LLVM with custom IR operations and that won't work on emscripten without some work on their end.
I'm aware of the existence of libobjc2, and I gather that I'll need to use clang rather than GCC, but I can't find any basic instructions of what's different about the compilation process.
Can anyone give explicit, step-by-step instructions on acquiring, configuring, compiling, and using GNUstep with Objective-C 2.0 in Ubuntu?
Since the GNUStep ObjC2 FAQ has already been referenced, I'll assume you've had a look. I would like to point this out, however:
For more advanced features, currently only supported if you compile with Clang, you will need the GNUstep runtime. This is not currently considered production ready. It should work as a drop-in replacement for the GCC runtime, but some of the advanced features are not well-tested.
The FAQ also calls out the following:
If you are using a recent version of GCC to compile your code then you should have a copy of the Objective-C runtime library that came with your compiler.
If you compile with the -fobjc-nonfragile-abi flag then you will use the new ABI. This is only supported with the GNUstep runtime. This adds:
Property introspection
Introspection on optional protocol methods
Non-fragile instance variables
Forwarding proxy support
So, if you're looking for older functionality via GCC, this tutorial would do the job nicely, as would this one. You've explicitly called out that you're looking to do this with the functionality provided by Clang (via libobjc2), which has its own bed of documentation.
Obtaining a release of Clang and getting set up seems fairly cut and dried. The LLVM Getting Started document is exceptionally robust (full documentation archive here), which should provide insight into getting the backend set up and compiling properly. Some additional insight into the expected build procedure can be found here.
However, compiling an Objective-C application in Clang seems extremely underdocumented and untested at the time of this writing. As features become available and the codebase stabilizes, I imagine more user documentation will go live.
According to the GNUstep Wiki, you need just need to compile your code with -fblocks and -fobjc-nonfragile-abi. Then you just use the language features in your code.