Computer program which translates code from one programming language to another

Compiler

Compiler

In <a href="/en/Computing" title="Computing" class="wl">computing</a>, a compiler is a <a href="/en/Computer_program" title="Computer program" class="wl">computer program</a> that <a href="/en/Translator_(computing)" title="Translator (computing)" class="wl">translates</a> computer code written in one <a href="/en/Programming_language" title="Programming language" class="wl">programming language</a> (the source language) into another language (the target language). The name "compiler" is primarily used for programs that translate <a href="/en/Source_code" title="Source code" class="wl">source code</a> from a <a href="/en/High-level_programming_language" title="High-level programming language" class="wl">high-level programming language</a> to a <a href="/en/Lower_level_language" title="Lower level language" class="mw-redirect wl">low-level programming language</a> (e.g. <a href="/en/Assembly_language" title="Assembly language" class="wl">assembly language</a>, <a href="/en/Object_code" title="Object code" class="wl">object code</a>, or <a href="/en/Machine_code" title="Machine code" class="wl">machine code</a>) to create an <a href="/en/Executable" title="Executable" class="wl">executable</a> program.<a href="#cite_note-1" style="counter-reset: mw-Ref 1;">[1]</a><a href="#cite_note-dragon-2" style="counter-reset: mw-Ref 2;">[2]</a>: p1 <a href="#cite_note-SUDARSANAM_MALIK_FUJITA_2002_pp._506–515-3" style="counter-reset: mw-Ref 3;">[3]</a>

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">Computer program which translates code from one programming language to another</div>
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title="Execution (computing)" class="wl">Program execution</a></th></tr><tr><th class="sidebar-heading notheme" style="background-color: rgba(51, 153, 255, 0.15);">
General concepts</th></tr><tr><td class="sidebar-content" style="text-align: left;">
<ul><li><a href="/en/Computer_program" title="Computer program" class="wl">Code</a></li>
<li><a href="/en/Translator_(computing)" title="Translator (computing)" class="wl">Translation</a>
<ul><li><a href="/en/Compiler" title="Compiler" class="wl">Compiler</a>
<ul><li><a href="/en/Compile_time" title="Compile time" class="wl">Compile time</a></li></ul></li>
<li><a href="/en/Optimizing_compiler" title="Optimizing compiler" class="wl">Optimizing compiler</a></li></ul></li>
<li><a href="/en/Intermediate_representation" title="Intermediate representation" class="wl">Intermediate representation</a> (IR)</li>
<li><a href="/en/Execution_(computing)" title="Execution (computing)" class="wl">Execution</a>
<ul><li><a href="/en/Runtime_system" title="Runtime system" class="wl">Runtime system</a>
<ul><li><a href="/en/Runtime_(program_lifecycle_phase)" title="Runtime (program lifecycle phase)" class="wl">Runtime</a></li></ul></li>
<li><a href="/en/Executable" title="Executable" class="wl">Executable</a></li>
<li><a href="/en/Interpreter_(computing)" title="Interpreter (computing)" class="wl">Interpreter</a></li>
<li><a href="/en/Virtual_machine" title="Virtual machine" class="wl">Virtual machine</a></li></ul></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background-color: rgba(51, 153, 255, 0.15);">
Types of code</th></tr><tr><td class="sidebar-content" style="text-align: left;">
<ul><li><a href="/en/Source_code" title="Source code" class="wl">Source code</a></li>
<li><a href="/en/Object_code" title="Object code" class="wl">Object code</a></li>
<li><a href="/en/Bytecode" title="Bytecode" class="wl">Bytecode</a></li>
<li><a href="/en/Machine_code" title="Machine code" class="wl">Machine code</a></li>
<li><a href="/en/Microcode" title="Microcode" class="wl">Microcode</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background-color: rgba(51, 153, 255, 0.15);">
Compilation strategies</th></tr><tr><td class="sidebar-content" style="text-align: left;">
<ul><li><a href="/en/Ahead-of-time_compilation" title="Ahead-of-time compilation" class="wl">Ahead-of-time</a> (AOT)</li>
<li><a href="/en/Just-in-time_compilation" title="Just-in-time compilation" class="wl">Just-in-time</a> (JIT)
<ul><li><a href="/en/Tracing_just-in-time_compilation" title="Tracing just-in-time compilation" class="wl">Tracing just-in-time</a></li>
<li><a href="/en/Compile_and_go_system" title="Compile and go system" class="wl">Compile and go system</a></li></ul></li>
<li><a href="/en/Precompilation" title="Precompilation" class="mw-redirect wl">Precompilation</a></li>
<li><a href="/en/Source-to-source_compiler" title="Source-to-source compiler" class="wl">Transcompilation</a></li>
<li><a href="/en/Dynamic_recompilation" title="Dynamic recompilation" class="wl">Recompilation</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background-color: rgba(51, 153, 255, 0.15);">
Notable runtimes</th></tr><tr><td class="sidebar-content" style="text-align: left;">
<ul><li><a href="/en/Android_Runtime" title="Android Runtime" class="wl">Android Runtime</a> (ART)</li>
<li><a href="/en/BEAM_(Erlang_virtual_machine)" title="BEAM (Erlang virtual machine)" class="wl">BEAM</a></li>
<li><a href="/en/Common_Language_Runtime" title="Common Language Runtime" class="wl">Common Language Runtime</a> (CLR) and&nbsp;<a href="/en/Mono_(software)#Code_Execution_Engine" title="Mono (software)" class="wl">Mono</a></li>
<li><a href="/en/CPython" title="CPython" class="wl">CPython</a> and&nbsp;<a href="/en/PyPy" title="PyPy" class="wl">PyPy</a></li>
<li><a href="/en/Crt0" title="Crt0" class="wl">crt0</a></li>
<li><a href="/en/Java_virtual_machine" title="Java virtual machine" class="wl">Java virtual machine</a> (JVM)</li>
<li><a href="/en/LuaJIT" title="LuaJIT" class="wl">LuaJIT</a></li>
<li><a href="/en/Objective-C" title="Objective-C" class="wl">Objective-C</a> and&nbsp;<a href="/en/Swift_(programming_language)" title="Swift (programming language)" class="wl">Swift</a>'s</li>
<li><a href="/en/V8_(JavaScript_engine)" title="V8 (JavaScript engine)" class="wl">V8</a> and&nbsp;<a href="/en/Node.js" title="Node.js" class="wl">Node.js</a></li>
<li><a href="/en/Zend_Engine" title="Zend Engine" class="wl">Zend Engine</a></li></ul></td>
</tr><tr><th class="sidebar-heading notheme" style="background-color: rgba(51, 153, 255, 0.15);">
Notable compilers &amp; toolchains</th></tr><tr><td class="sidebar-content" style="text-align: left;">
<ul><li><a href="/en/GNU_Compiler_Collection" title="GNU Compiler Collection" class="wl">GNU Compiler Collection</a> (GCC)</li>
<li><a href="/en/LLVM" title="LLVM" class="wl">LLVM</a> and&nbsp;<a href="/en/Clang" title="Clang" class="wl">Clang</a></li></ul></td>
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There are many different types of compilers which produce output in different useful forms. A <a href="/en/Cross-compiler" title="Cross-compiler" class="mw-redirect wl">cross-compiler</a> produces code for a different <a href="/en/Central_processing_unit" title="Central processing unit" class="wl">CPU</a> or <a href="/en/Operating_system" title="Operating system" class="wl">operating system</a> than the one on which the cross-compiler itself runs. A <a href="/en/Bootstrap_compiler" title="Bootstrap compiler" class="mw-redirect wl">bootstrap compiler</a> is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language.

Related software include, a program that translates from a low-level language to a higher level one is a <a href="/en/Decompiler" title="Decompiler" class="wl">decompiler</a>&nbsp;; a program that translates between high-level languages, usually called a <a href="/en/Source-to-source_compiler" title="Source-to-source compiler" class="wl">source-to-source compiler</a> or transpiler. A language <a href="/en/Rewriting" title="Rewriting" class="wl">rewriter</a> is usually a program that translates the form of <a href="/en/Expression_(computer_science)" title="Expression (computer science)" class="wl">expressions</a> without a change of language. A <a href="/en/Compiler-compiler" title="Compiler-compiler" class="wl">compiler-compiler</a> is a compiler that produces a compiler (or part of one), 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: <a href="/en/Preprocessor" title="Preprocessor" class="wl">preprocessing</a>, <a href="/en/Lexical_analysis" title="Lexical analysis" class="wl">lexical analysis</a>, <a href="/en/Parsing" title="Parsing" class="wl">parsing</a>, <a href="/en/Semantic_analysis_(compilers)" title="Semantic analysis (compilers)" class="wl">semantic analysis</a> (<a href="/en/Syntax-directed_translation" title="Syntax-directed translation" class="wl">syntax-directed translation</a>), conversion of input programs to an <a href="/en/Intermediate_representation" title="Intermediate representation" class="wl">intermediate representation</a>, <a href="/en/Code_optimization" title="Code optimization" class="mw-redirect wl">code optimization</a> and <a href="/en/Code_generation_(compiler)" title="Code generation (compiler)" class="wl">machine specific code generation</a>. Compilers generally implement these phases as modular components, promoting efficient design and correctness of <a href="/en/Program_transformation" title="Program transformation" class="wl">transformations</a> 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 <a href="/en/Compiler_correctness" title="Compiler correctness" class="wl">compiler correctness</a>.<a href="#cite_note-Sun2016-4" style="counter-reset: mw-Ref 4;">[4]</a>

Compilers are not the only language processor used to transform source programs. An <a href="/en/Interpreter_(computing)" title="Interpreter (computing)" class="wl">interpreter</a> is computer software that transforms and then executes the indicated operations.<a href="#cite_note-dragon-2" style="counter-reset: mw-Ref 2;">[2]</a>: p2  The translation process influences the design of computer languages, which leads to a preference of compilation or interpretation. In theory, a programming language can have both a compiler and an interpreter. In practice, programming languages tend to be associated with just one (a compiler or an interpreter).

In computing, a compiler is a computer program that translates computer code written in one programming language into another language . The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language to create an executable program. There are many different types of compilers which produce output in different useful forms. A cross-compiler  produces code for a different 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, a program that translates from a low-level language to a higher level one is a decompiler ; a program that translates between high-level languages, usually called a source-to-source compiler or transpiler.  A language rewriter is usually a program that translates the form of expressions without a change of language.  A compiler-compiler is a compiler that produces a compiler , often in a generic and reusable way so as to be able to produce many differing compilers. 