What is llvm clang

It automates many of the difficult and unpleasant tasks involved in language creation, such as porting the outputted code to multiple platforms and architectures. LLVM is a framework to generate object code from any kind of source code. When it comes to performance differences, GCC has been considered superior in the past. But LLVM is gaining ground. Then the LLVM clang code generator on the back end turns the interim format into final machine code.

A major feature of klee is that it can produce a testcase in the event that it detects a bug. The LLD project is a new linker. That is a drop-in replacement for system linkers and runs much faster. A major strength of LLVM is its versatility, flexibility, and reusability, which is why it is being used for such a wide variety of different tasks: everything from doing light-weight JIT compiles of embedded languages like Lua to compiling Fortran code for massive super computers.

As much as everything else, LLVM has a broad and friendly community of people who are interested in building great low-level tools. For information on how to send in a patch, get commit access, and copyright and license topics, please see the LLVM Developer Policy.

LLVM is publicly available under an open source License. This award is given by ACM to one software system worldwide every year. New languages, and improvements on existing ones, are mushrooming throughout the develoment landscape. Why now? One big reason is new tools for building languages—specifically, compilers. LLVM makes it easier to not only create new languages, but to enhance the development of existing ones.

It provides tools for automating many of the most thankless parts of the task of language creation: creating a compiler, porting the outputted code to multiple platforms and architectures, generating architecture-specific optimizations such as vectorization, and writing code to handle common language metaphors like exceptions.

Its liberal licensing means it can be freely reused as a software component or deployed as a service. The roster of languages making use of LLVM has many familiar names. Mono, the. At its heart, LLVM is a library for programmatically creating machine-native code. A developer uses the API to generate instructions in a format called an intermediate representation , or IR.

LLVM can then compile the IR into a standalone binary or perform a JIT just-in-time compilation on the code to run in the context of another program, such as an interpreter or runtime for the language. For example, almost every language has the concept of a function and of a global variable, and many have coroutines and C foreign-function interfaces.

LLVM has functions and global variables as standard elements in its IR, and has metaphors for creating coroutines and interfacing with C libraries. To understand LLVM, it might help to consider an analogy to the C programming language: C is sometimes described as a portable, high-level assembly language, because it has constructions that can map closely to system hardware, and it has been ported to almost every system architecture.

One way it accomplishes this portability is by offering primitives independent of any particular machine architecture. You can create primitive integer types using as many bits as needed, like a bit integer. But LLVM makes other things possible as well. Some situations require code to be generated on the fly at runtime, rather than compiled ahead of time. The Julia language , for example, JIT-compiles its code, because it needs to run fast and interact with the user via a REPL read-eval-print loop or interactive prompt.

Numba , a math-acceleration package for Python, JIT-compiles selected Python functions to machine code.