Control-flow analysis: Difference between revisions

Revision as of 12:43, 19 May 2011

Latest revision as of 22:15, 5 August 2024

(48 intermediate revisions by 29 users not shown)

Line 1:

{{Short description|Compiler technique}}

'''Control flow analysis''' is a [[static code analysis]] technique for determining the [[control flow]] of a program. The control flow is expressed as a [[control flow graph]] (CFG).

{{Cleanup-rewrite|date=July 2014}}

In [[computer science]], '''control-flow analysis''' ('''CFA''') is a [[static code analysis|static-code-analysis]] technique for determining the [[control flow]] of a program. The control flow is expressed as a [[control-flow graph]] (CFG). For both [[functional programming language]]s and [[object-oriented programming language]]s, the term CFA, and elaborations such as ''k''-CFA, refer to specific algorithms that compute control flow.{{dubious|date=July 2014}}

For many languages[[imperative programming language]]s, the control flow of a program is explicit in a program's source code.{{dubious|date=July 2014}} As a result, [[interprocedural analysis|interprocedural]] control-flow analysis implicitly usually refers to a [[static analysis]] technique for determining the receiver(s)receivers of function or method calls in computer programs written in a [[higher-order programming language]].{{dubious|date=July 2014}} For bothexample, [[functionalin a programming language with [[higher-order function]]s andlike [[object-orientedScheme (programming language)|Scheme]]s, the termtarget [[CFA]]of refersa tofunction ancall algorithmmay thatnot computesbe controlexplicit: flow.in the isolated expression

<syntaxhighlight lang="scheme">

The term '''control flow analysis''' was introduced independently by Neil D. Jones<ref>{{citation

(lambda (f) (f x))

| author = Neil D. Jones

</syntaxhighlight>

| title = Flow analysis of lambda expressions

| journal = Automata, Languages and Programming

| year = 1981

| doi = 10.1007/3-540-10843-2_10

| pages = 114–128

}}</ref> and Olin Shivers<ref>{{citation

| last = Shivers

| first = Olin

| title = Control-flow analysis in Scheme

| pages = 164–174

| note = Reprinted in \emph{20 Years of the ACM SIGPLAN Conference on

Programming Language Design and Implementation (1979--1999):

A Selection

| journal = Proceedings of the ACM SIGPLAN'88 Conference on Programming Language Design and Implementation (PLDI)

| series = SIGPLAN Notices, Vol.23, No.7

| year = 1988

| doi = 10.1145/53990.54007

}}</ref>.

it is unclear to which procedure <code>f</code> may refer. To determine the possible targets, aA control-flow analysis must consider where this expression could be invoked, and what argument it may receive to determine the possible targets.

In a programming language like Scheme, the target of a function call may not be explicit. For example in the isolated expression:

Techniques such as [[abstract interpretation]], [[constraint solving]], and [[type system]]s may be used for control-flow analysis.<ref>{{cite book |author-first1=Flemming |author-last1=Nielson |author-first2=Hanne Riis |author-last2=Nielson |author2-link=Hanne Riis Nielson|author-first3=Chris |author-last3=Hankin |title=Principles of Program Analysis |publisher=[[Springer Science+Business Media]] |date=2005}}</ref>{{page needed|date=July 2014}}

(lambda (f) (f x))

==See also==

it is unclear to which procedure <code>f</code> may refer. To determine the possible targets, a control-flow analysis must consider where this expression could be invoked, and what argument it may receive.

* [[Control-flow diagram]] (CFD)

* [[Data-flow analysis]]

* [[Cartesian product algorithm]]

[[Abstract interpretation]], [[constraint solving]] and [[type system]]s may be used to compute control-flow analysis.

* [[Pointer analysis]]

==References==

{{reflist}}

==External links==

{{Commonscat| title = Control-flow analysis in Scheme}}

*[https://web.archive.org/web/20140728203154/http://pages.cs.wisc.edu/~cs701-1/NOTES/3.CONTROL-FLOW-ANALYSIS.html for textbook intraprocedural CFA in imperative languages]

*[http://janmidtgaard.dk/papers/Midtgaard-CSur-final.pdf CFA in functional programs (survey)]

*[http://cgi.di.uoa.gr/~smaragd/kcfa-pldi10.pdf for the relationship between CFA analysis in functional languages and points-to analysis in imperative/OOP languages]

{{Compiler optimizations}}

[[Category:Control-flow analysis| ]]