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Libjit is a library which provides standard means for fast dynamic "just-in-time" compilation. Unlike different tools such as nanojit, GNU lightning, and LLVM, libjit is open source and free software. It's also faster and more platform-independent, and easier in usage and support. ... [More] Libjit can be used on many operating systems and platforms. This includes the GNU/Linux, GNU, Hurd, Linux, Debian, Ubuntu, Suse, RedHat, Fedora Core, Windows, Windows Vista, Windows XP and many other operating systems, hardware and software platforms. This web site contains the libjit-linear-scan library which is based on libjit. We study and research in the field of fast "just-in-time" compilation, dynamic compilation, and dynamic binary translation. We study register allocation, generation of machine code, optimization. More specifically, this include linear scan register allocation, CLR, ECMA-334, ECMA-335, Microsoft Common Intermediate Language, virtual machines, embedded systems, and cloud computing. If you are looking for the official version please check out the DotGNU site. Free software for advanced just-in-time and dynamic compilationThe design of libjit and its original source code base were constructed by Rhys Weatherley and Norbert Bollow. They built the DotGNU and the Portable.NET implementation of the Common Language Infrastructure for the Free Software Foundation. Later Kirill Kononenko, Klaus Treichel, Aleksey Demakov and other developers continued the development and design of this library. These researchers fixed the source code and added a few missing parts for a libjit 0.1.2 release. This version is suitable for fast "just-in-time" compilation and dynamic optimization. Secondly, they created with the libjit a just-in-time compiler for the GNU Portable.NET JIT and added a new codec parser into the GNU Portable.NET. Why should we dynamically compile with the libjit library and its API?Libjit supports a standartized API. It's independent of the bytecode format, of the garbage collector, of the shared libraries and the bytecode specifics. We provide standard means for arithmetic operations, types conversions, exceptions handling and memory accesses. Libjit is in our opinion the best library for development of advanced "just-in-time "compilation in virtual machine implementations, domain-specific languages, dynamic programming languages, dynamic verification, and script languages. Unlike the nano JIT, GNU lightning, and the LLVM, Libjit provides all of the following properties, and features: The compilation time with libjit aims to become deterministic and linear Libjit is suitable for just-in-time and fast dynamic compilation Binary code that libjit generates is of a very high quality for a fast compiler Libjit is platform independent. Compilation of the source code needs a C language GCC, IBM compatible compiler for platform that performs just-in-time compilation. An aggressive support of more optimized just-in-time compilation for the target platforms include: IA-32 (this support is of production quality) AMD64 (under major development) ARM (we have an experimental support), Alpha DEC (implementation started by Thomas Cort in Google Summer of Code 2006) We believe that a support of new hardware and software platforms by other software developers can be done very quickly. When libjit doesn't know how to generate binary code it fallbacks into an interpretation mode. The design and the architecture of the libjit API have been very well tested in Linux and Windows real-time embedded systems, industrial software, production automation and machinery industry Libjit has a remarkably easy API for usage by the software developers. A simple just-in-time compiler can be built in 5 minutes. A simple support of the just-in-time compilation like one in the VMKit for the MSIL and the Java byte code can be created in a few weeks. A support of a high level industry production can be complete in 2 - 3 months We develop the Libjit-Linear Scan library Libjit is a Free Software product that is independent of any proprietary company interests Libjit is free and it can be used free of charge by commercial software, by research projects and by the open source and Free Software community and in the static compilers and in proprietary software. Libjit can be applied for dynamic compilation by a syntax analysis of MSIL, Java bytecode, Ruby, Python, Perl, LLVM (LLVA) bytecode and many other virtual machines. Libjit allows us to add support of fast dynamic "just-in-time" compilation in new software one time for a long time. Software which use libjit can use new hardware features like multi-cores without any extra changes in itself Libjit is open for new ideas and features which can be later applied in industrial applications and research The engineers and the researchers that are involved into the development of libjit are hard-working, open-minded, and highly-cooperative Why do you have this web page? Is this a fork of libjit? Should I use this branch of the libjit library?- No this is not a fork. This is a research branch of libjit. How was created this source code base?While we made an integration of a variant of an optimal linear scanning algorithm into the libjit we found that a lot of research and development are required to make the optimization useful. We created this branch of libjit and added a support of a few optimizations. For example, we support a few "optimal" register allocations and data-flow and control-flow analysis. These algorithms are enabled with various optimization levels and they are adaptive. We hope that our research helps other software projects that already use or implement dynamic compilation See more information and downloads section for many answers of questions including this short review, how productivity of the libjit design and its approach for just-in-time and fast dynamic compilation compares to use for this task of LLVM or GNU lightning The old source code of the libjit linear scan 0.1.2.5 are available for a download from the svn repository. You can have a look at the svn for a package of the source code of the libjit linear scan 0.1.2.5, for the documentation and research papers and benchmarks and the review of its architecture please have a look at downloads. This release included besides a support of a few features of the git repository: Optimization levels for IA-32 from 0 to 4 (jit_function_set_optimization_level) A new specializing Application Binary Interface (jit_abi_internal) A brand new optimizing binary code generator There are supported 4 levels of optimization A few low-level machine dependent optimizations An aggressive optimization of division by integer constants with reciprocals as by Torbjorn Granlund and Peter L. Montgomery in "Division By Invariant Integers using Multiplication" divcnst-pldi94.pdf Templates for generation of MMX/Streaming SIMD Extensions/SSE/SSE2/SSE3 instructions A usage of SIMD SSE/SSE2/SSE3 for floating point values and operations Fast static live variable analysis with level 2 of optimization Dead-code elimination with level 4 of optimization Static live variable analysis with level 3, 4 of optimization A linear scanning register allocation algorithm (level 2) based on algorithm proposed by Massimiliano Poletto and Vivek Sarkar A second-chance binpacking register allocation algorithm (level 3, 4) The design of this extension has been well tested in regression tests and .NET applications and the GNU Portable.NET Where is libjit library used? For example, do you use it?Yes we use it. Libjit was applied in industrial lasers produced by the TRUMPF Laser division in their embedded systems software. These lasers use GNU Portable.NET, a GNU Portable.NET just-in-time compiler and a GNU Portable.NET managed implementation of Windows.Forms class from Microsoft .NET Framework Libjit research is applied as a research base in a few independent research projects: ILDJIT that is developed by Simone Campanoni and the Formal Languages and Compilers Group Politecnico di Milano. See ILDJIT for the documentation and the papers about how libjit has been applied into the ILDJIT Another application of the Libjit library research is in the HornetsEye that is developed by Jan Wedekind and the Mobile Machines and Vision Laboratory (MMVL), that is a part of the Centre for Robotics and Automation (CENRA) at the Materials and Engineering Research Institute (MERI). See the HornetsEye website for documentations, papers, and video about how libjit is used for real-time image and video processing with Ruby Where can I find the documentation and the tutorials?http://www.gnu.org/software/dotgnu/libjit-doc/libjit.html The primary interface is in C, for maximal reusability. Class interfaces are available for programmers who prefer C++. Designed for portability to all major 32-bit and 64-bit platforms. Simple three-address API for library users, but opaque enough that other representations can be used inside the library in future without affecting existing users. Up-front or on-demand compilation of any function. In-built support to re-compile functions with greater optimization, automatically redirecting previous callers to the new version. Fallback interpreter for running code on platforms that don’t have a native code generator yet. This reduces the requirement for the programmers to write their own interpreters for these platforms. Arithmetic, bitwise, conversion, and comparison operators for 8-bit, 16-bit, 32-bit, or 64-bit integer types; and 32-bit, 64-bit, or longer floating point types. Includes overflow detecting arithmetic for integer types. Large set of mathematical and trigonometric operations (sqrt, sin, cos, min, abs, etc) for inlining floating-point library functions. Simplified type layout and exception handling mechanisms, upon which a variety of different object models can be built. Support for nested functions, able to access their parent’s local variables (for implementing Pascal-style languages). --Rhys Weatherley The mailing lists and google groupsGNU Portable.NET just-in-time compiler and libjit library? Email Dotgnu-pnet mailing list Libjit library? Email GNU libjit developers mailing list Libjit linear scan? Email GNU libjit developers mailing list or libjit-linear-scan-register-allocator-dev google group If you want to ask about a usage of libjit with any other project you probably might be interested to contact mailing lists of these projects. We think the following projects can be interested to usage of libjit: Mono and Libjit Email Mono-devel mailing list GCC and Libjit? Email GCC mailing list ILDJIT and Libjit? Email ILDJIT mailing list Ruby and Libjit? Use Ruby forum Parrot and Libjit? Email Parrot-dev mailing list Perl and Libjit? Email Perl5.porters mailing list Python and Libjit? Email Python-dev mailing list How can you contribute to development of Libjit? How can you get new improvements in Libjit that your group want for its software and hardware platform?Your job queries and monetary donations can help us to contribute more of our precious time. Please use savannah and libjit mailing list for a submission of your patch or to report a bug you found. Please tell us your thoughts, share your idea about how you want to use the libjit library. Please let us know your suggestions on how the libjit community can improve the libjit library even better for you, for your business needs or your cutting edge research project. If you are interested in a submission of your source code or a patch of a new "smart" algorithm or you find a need for a repository access then you probably may want an access to the repository of the libjit linear scan. If you plan to contribute any source code or participate in the development please contact us. Hence, we can cooperate with the highest productivity. Related projects A project led by Novell (formerly by Ximian) to create an ECMA standard compliant, .NET-compatible set of tools, including among others a C# compiler and a CLR implementation. A software framework available with several Microsoft Windows operating systems. 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