Linker (computing) in the context of Development tool

A dynamic linker is an operating system feature that loads and links dynamic libraries for an executable at runtime; before or while it is running. Although the details vary by operating system, typically, a dynamic linker copies the content of each library from persistent storage to RAM, fills jump tables and relocates pointers.

Linking is often referred to as a process that is performed when the executable is compiled, while a dynamic linker is a special part of an operating system that loads external shared libraries into a running process and then binds those shared libraries dynamically to the running process. This approach is also called dynamic linking or late linking.

In computing, just-in-time (JIT) compilation (also dynamic translation or run-time compilations) is compilation (of computer code) during execution of a program (at run time) rather than before execution. This may consist of source code translation but is more commonly bytecode translation to machine code, which is then executed directly. A system implementing a JIT compiler typically continuously analyses the code being executed and identifies parts of the code where the speedup gained from compilation or recompilation would outweigh the overhead of compiling that code.

JIT compilation is a combination of the two traditional approaches to translation to machine code: ahead-of-time compilation (AOT), and interpretation, which combines some advantages and drawbacks of both. Roughly, JIT compilation combines the speed of compiled code with the flexibility of interpretation, with the overhead of an interpreter and the additional overhead of compiling and linking (not just interpreting). JIT compilation is a form of dynamic compilation, and allows adaptive optimization such as dynamic recompilation and microarchitecture-specific speedups. Interpretation and JIT compilation are particularly suited for dynamic programming languages, as the runtime system can handle late-bound data types and enforce security guarantees.

LLVM is a set of compiler and toolchain technologies that can be used to develop a frontend for any programming language and a backend for any instruction set architecture. LLVM is designed around a language-independent intermediate representation (IR) that serves as a portable, high-level assembly language that can be optimized with a variety of transformations over multiple passes. The name LLVM originally stood for Low Level Virtual Machine. However, the project has since expanded, and the name is no longer an acronym but an orphan initialism.

LLVM is written in C++ and is designed for compile-time, link-time, and runtime optimization. Originally implemented for C and C++, the language-agnostic design of LLVM has since spawned a wide variety of frontends: languages with compilers that use LLVM (or which do not directly use LLVM but can generate compiled programs as LLVM IR) include ActionScript, Ada, C# for .NET, Common Lisp, PicoLisp, Crystal, CUDA, D, Delphi, Dylan, Forth, Fortran, FreeBASIC, Free Pascal, Halide, Haskell, Idris, Jai (only for optimized release builds), Java bytecode, Julia, Kotlin, LabVIEW's G language, Objective-C, OpenCL, PostgreSQL's SQL and PL/pgSQL, Ruby, Rust, Scala, Standard ML, Swift, Xojo, and Zig.

A dynamic library is a library that contains functions and data that can be consumed by a computer program at run-time as loaded from a file separate from the program executable. Dynamic linking or late binding allows for using a dynamic library by linking program library references with the associated objects in the library either at load-time or run-time. At program build-time, the linker records what library objects the program uses. When the program is run, a dynamic linker or linking loader associates program library references with the associated objects in the library.

A dynamic library can be linked at build-time to a stub for each library resource that is resolved at run-time. Alternatively, a dynamic library can be loaded without linking to stubs.

The Western Design Center (WDC), located in Mesa, Arizona, is a company that develops intellectual property for, and licenses manufacture of, MOS Technology 65xx based microprocessors and microcontrollers. WDC was founded in 1978 by a former MOS Technology employee and co-holder of the MOS Technology 6502 patent, Bill Mensch. Prior to leaving MOS Technology in 1977 Bill was the microprocessor design manager at MOS Technology.

Beyond discrete devices, WDC offers device designs in the form of semiconductor intellectual property cores (IP cores) to use inside other chips such as application-specific integrated circuit (ASICs), and provides ASIC and embedded systems consulting services revolving around their processor designs. WDC also produces C compilers, assembler/linker packages, simulators, development–evaluation printed circuit boards, and in-circuit emulators for their processors.