compilation

In the music industry, a compilation is a release by a record label that features a few tracks from a collection of different bands. These serve three different purposes:
- For record labels, it is a chance to showcase new material or acts. By placing a couple of tracks (perhaps new or unreleased) from established acts, then sticking a bunch of upcoming acts on the compilation, you get circulation for the new bands. People will buy based on the acts they know and get exposed to the new stuff.
- For independent artists, it is a chance to get a recording released and distributed under a label.
- For small labels, it is a way to generate capitol and garner a following.

Compilations are usually referred to as 'Comps'.

Compilation is the task of transforming a computer program written in some source language to a program with equivalent semantics in some target language. Compilation is performed by another computer program called a compiler. The source language is usually some programming language, like C, C++, or Java. The target language is most often some sort of machine language. Exceptions exist -- the Java bytecode compiler, javac, and the Java virtual machine with just-in-time compilation being the notable example.

For the common case of compiling source code to machine code, compilation occurs in a series of stages, as diagrammed below:

source code

↓ lexical analysis (or scanning)
token stream
↓ syntactic analysis (or parsing)
parse tree & symbol table
↓ semantic analysis
parse tree & symbol table
↓ language-specific optimizations (or high-level optimizations)
parse tree & symbol table
↓ intermediate format generation

intermediate format

↓ general optimizations and additional program transformations

intermediate format

↓ code generation
machine code
↓ machine-specific optimizations (or low-level optimizations)

machine code (or object code)

The first set of steps comprise the front end of the compiler. The front end is responsible for transforming the source code to an intermediate format. The last set of steps comprise the back end of the compiler. The back end transforms the intermediate format to machine code.

The intermediate format is an abstract representation of the program being compiled. The intermediate format is independent of both the source programming language and the instruction-set architecture of the target machine. The purpose of having an intermediate format is to de-couple the front end from the back end. This way, the front end can be made independent of the instruction-set architecture, and the back end of can be made independent of the source language. Doing this makes it easier to write general optimizations and transformations that can operate on any program. It also makes it easier to write compiler systems that operate on many languages and architectures, such as gcc.

Com"pi*la"tion (?), n. [L. compilatio: cf. F. compilation.]

1.

The act or process of compiling or gathering together from various sources.

2.

That which is compiled; especially, a book or document composed of materials gathering from other books or documents.

His [Goldsmith's] compilations are widely distinguished from the compilations of ordinary bookmakers. Macaulay.

 

© Webster 1913.