mirror of
https://github.com/github/codeql.git
synced 2025-12-23 12:16:33 +01:00
f07a7bf8cf
Will need subsequent PRs fixing up test failures (due to deprecated methods moving around), but other than that everything should be straight-forward.
29 lines
858 B
Plaintext
29 lines
858 B
Plaintext
/**
|
|
* @name String concatenation in loop
|
|
* @description Concatenating strings in loops has quadratic performance.
|
|
* @kind problem
|
|
* @tags efficiency
|
|
* maintainability
|
|
* @problem.severity recommendation
|
|
* @sub-severity low
|
|
* @precision low
|
|
* @id py/string-concatenation-in-loop
|
|
*/
|
|
|
|
import python
|
|
|
|
predicate string_concat_in_loop(BinaryExpr b) {
|
|
b.getOp() instanceof Add and
|
|
exists(SsaVariable d, SsaVariable u, BinaryExprNode add |
|
|
add.getNode() = b and d = u.getAnUltimateDefinition()
|
|
|
|
|
d.getDefinition().(DefinitionNode).getValue() = add and
|
|
u.getAUse() = add.getAnOperand() and
|
|
add.getAnOperand().pointsTo().getClass() = ClassValue::str()
|
|
)
|
|
}
|
|
|
|
from BinaryExpr b, Stmt s
|
|
where string_concat_in_loop(b) and s.getASubExpression() = b
|
|
select s, "String concatenation in a loop is quadratic in the number of iterations."
|