Editing Dynamic compilation (section)

{{Program execution}}

'''Dynamic compilation''' is a process used by some [[programming language]] implementations to gain performance during program execution. Although the technique originated in [[Smalltalk]],<ref>Peter L. Deutsch and Alan Schiffman. "Efficient Implementation of the Smalltalk-80 System", 11th Annual Symposium on Principles of Programming Languages, Jan 1984, pp. 297-302</ref> the best-known language that uses this technique is [[Java (programming language)|Java]]. Since the [[machine code]] emitted by a dynamic compiler is constructed and optimized at program runtime, the use of dynamic compilation enables optimizations for efficiency not available to statically-compiled programs (i.e. those compiled by a so-called "batch compiler", as written below) except through [[Duplicate code|code duplication]] or [[metaprogramming]].

[[Runtime environment]]s using dynamic compilation typically have programs run slowly for the first few minutes, and then after that, most of the compilation and recompilation is done and it runs quickly. Due to this initial performance lag, dynamic compilation is undesirable in certain cases. In most implementations of dynamic compilation, some optimizations that could be done at the initial [[compile time]] are delayed until further compilation at [[Run time (program lifecycle phase)|run-time]], causing further unnecessary slowdowns. [[Just-in-time compilation]] is a form of dynamic compilation.