Editing Compiler (section)

{{Short description|Computer program which translates code from one programming language to another}}
{{About|software to translate computer languages|the manga|Compiler (manga)}}
{{Redirect2|Compile|Compiling|the software company|Compile (company)|other uses|Compilation (disambiguation){{!}}Compilation}}
{{Use dmy dates|date=October 2020}}
{{Program execution}}

In [[computing]], a '''compiler''' is a [[computer program]] that [[Translator (computing)|translates]] computer code written in one [[programming language]] (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate [[source code]] from a [[high-level programming language]] to a [[lower level language|low-level programming language]] (e.g. [[assembly language]], [[object code]], or [[machine code]]) to create an [[executable]] program.<ref>{{cite web |author= |date= |title=Encyclopedia: Definition of Compiler |url=https://www.pcmag.com/encyclopedia/term/compiler |access-date=2 July 2022 |work=PCMag.com}}</ref><ref name="dragon">[[Compilers: Principles, Techniques, and Tools]] by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007</ref>{{rp|p1}}<ref name="SUDARSANAM MALIK FUJITA 2002 pp. 506–515">{{cite book | last1=Sudarsanam | first1=Ashok | last2=Malik | first2=Sharad | last3=Fujita | first3=Masahiro | title=Readings in Hardware/Software Co-Design | chapter=A Retargetable Compilation Methodology for Embedded Digital Signal Processors Using a Machine-Dependent Code Optimization Library | publisher=Elsevier | date=2002 | doi=10.1016/b978-155860702-6/50045-4 | pages=506–515 | isbn=9781558607026 | quote=A compiler is a computer program that translates a program written in a high-level language (HLL), such as C, into an equivalent assembly language program [2]. }}</ref>

There are many different types of compilers which produce output in different useful forms. A ''[[cross-compiler]]''  produces code for a different [[Central processing unit|CPU]] or [[operating system]] than the one on which the cross-compiler itself runs.  A ''[[bootstrap compiler]]'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language.

Related software include ''[[decompiler]]s'', programs that translate from low-level languages to higher level ones; programs that translate between high-level languages, usually called ''[[source-to-source compiler]]s'' or ''transpilers''; language ''[[rewriting|rewriter]]s'', usually programs that translate the form of [[Expression (computer science)|expressions]] without a change of language; and ''[[compiler-compiler]]s'', compilers that produce compilers (or parts of them), often in a generic and reusable way so as to be able to produce many differing compilers.

A compiler is likely to perform some or all of the following operations, often called phases: [[Preprocessor|preprocessing]], [[lexical analysis]], [[parser|parsing]], [[Semantic analysis (compilers)|semantic analysis]] ([[syntax-directed translation]]), conversion of input programs to an [[intermediate representation]], [[code optimization]] and [[code generation (compiler)|machine specific code generation]]. Compilers generally implement these phases as modular components, promoting efficient design and correctness of [[program transformation|transformation]]s of source input to target output. Program faults caused by incorrect compiler behavior can be very difficult to track down and work around; therefore, compiler implementers invest significant effort to ensure [[compiler correctness]].<ref name="Sun2016">{{cite book |last1=Sun|first1=Chengnian|last2=Le|first2=Vu|last3=Zhang|first3=Qirun|last4=Su|first4=Zhendong|title=Proceedings of the 25th International Symposium on Software Testing and Analysis |chapter=Toward understanding compiler bugs in GCC and LLVM |date=2016|chapter-url=http://dl.acm.org/citation.cfm?doid=2931037.2931074|publisher=ACM|series=ISSTA 2016|pages=294–305|doi=10.1145/2931037.2931074|isbn=9781450343909|s2cid=8339241}}</ref>