mirror of
https://github.com/github/codeql.git
synced 2026-04-26 09:15:12 +02:00
C#: Delete the existing structural comparison implementation.
This commit is contained in:
Michael Nebel
@@ -4,265 +4,3 @@
|
||||
*/
|
||||
|
||||
import csharp
|
||||
|
||||
/** Gets the declaration referenced by the expression `e`, if any. */
|
||||
private Declaration referenceAttribute(Expr e) {
|
||||
result = e.(MethodCall).getTarget()
|
||||
or
|
||||
result = e.(ObjectCreation).getTarget()
|
||||
or
|
||||
result = e.(Access).getTarget()
|
||||
}
|
||||
|
||||
/** Gets the AST node kind element `e`. */
|
||||
private int elementKind(ControlFlowElement e) {
|
||||
expressions(e, result, _)
|
||||
or
|
||||
exists(int k | statements(e, k) | result = -k)
|
||||
}
|
||||
|
||||
private int getNumberOfActualChildren(ControlFlowElement e) {
|
||||
if e.(MemberAccess).targetIsThisInstance()
|
||||
then result = e.getNumberOfChildren() - 1
|
||||
else result = e.getNumberOfChildren()
|
||||
}
|
||||
|
||||
/**
|
||||
* A configuration for performing structural comparisons of program elements
|
||||
* (expressions and statements).
|
||||
*
|
||||
* The predicate `candidate()` must be overridden, in order to identify the
|
||||
* elements for which to perform structural comparison.
|
||||
*
|
||||
* Each use of the library is identified by a unique string value.
|
||||
*/
|
||||
abstract class StructuralComparisonConfiguration extends string {
|
||||
bindingset[this]
|
||||
StructuralComparisonConfiguration() { any() }
|
||||
|
||||
/**
|
||||
* Holds if elements `x` and `y` are candidates for testing structural
|
||||
* equality.
|
||||
*
|
||||
* Subclasses are expected to override this predicate to identify the
|
||||
* top-level elements which they want to compare. Care should be
|
||||
* taken to avoid identifying too many pairs of elements, as in general
|
||||
* there are very many structurally equal subtrees in a program, and
|
||||
* in order to keep the computation feasible we must focus attention.
|
||||
*
|
||||
* Note that this relation is not expected to be symmetric -- it's
|
||||
* fine to include a pair `(x, y)` but not `(y, x)`.
|
||||
* In fact, not including the symmetrically implied fact will save
|
||||
* half the computation time on the structural comparison.
|
||||
*/
|
||||
abstract predicate candidate(ControlFlowElement x, ControlFlowElement y);
|
||||
|
||||
private predicate candidateInternal(ControlFlowElement x, ControlFlowElement y) {
|
||||
candidate(x, y)
|
||||
or
|
||||
exists(ControlFlowElement xParent, ControlFlowElement yParent, int i |
|
||||
candidateInternalChild(xParent, i, x, yParent)
|
||||
|
|
||||
y = yParent.getChild(i)
|
||||
)
|
||||
}
|
||||
|
||||
pragma[noinline]
|
||||
private predicate candidateInternalChild(
|
||||
ControlFlowElement x, int i, ControlFlowElement xChild, ControlFlowElement y
|
||||
) {
|
||||
candidateInternal(x, y) and
|
||||
xChild = x.getChild(i)
|
||||
}
|
||||
|
||||
private predicate sameByValue(Expr x, Expr y) { sameByValueAux(x, y, y.getValue()) }
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameByValueAux(Expr x, Expr y, string value) {
|
||||
candidateInternal(x, y) and
|
||||
value = x.getValue()
|
||||
}
|
||||
|
||||
private ControlFlowElement getRankedChild(ControlFlowElement cfe, int rnk, int i) {
|
||||
(candidateInternal(cfe, _) or candidateInternal(_, cfe)) and
|
||||
i =
|
||||
rank[rnk](int j |
|
||||
exists(ControlFlowElement child | child = cfe.getChild(j) |
|
||||
not (j = -1 and cfe.(MemberAccess).targetIsThisInstance())
|
||||
)
|
||||
) and
|
||||
result = cfe.getChild(i)
|
||||
}
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameByStructure0(
|
||||
ControlFlowElement x, ControlFlowElement y, int elementKind, int children
|
||||
) {
|
||||
candidateInternal(x, y) and
|
||||
elementKind = elementKind(x) and
|
||||
children = getNumberOfActualChildren(x) and
|
||||
not (x.(Expr).hasValue() and y.(Expr).hasValue())
|
||||
}
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameByStructure(ControlFlowElement x, ControlFlowElement y, int i) {
|
||||
i = 0 and
|
||||
// At least one of `x` and `y` must not have a value, they must have
|
||||
// the same kind, and the same number of children
|
||||
sameByStructure0(x, y, elementKind(y), getNumberOfActualChildren(y)) and
|
||||
// If one of them has a reference attribute, they should both reference
|
||||
// the same node
|
||||
(exists(referenceAttribute(x)) implies referenceAttribute(x) = referenceAttribute(y)) and
|
||||
// x is a member access on `this` iff y is
|
||||
(x.(MemberAccess).targetIsThisInstance() implies y.(MemberAccess).targetIsThisInstance()) and
|
||||
(y.(MemberAccess).targetIsThisInstance() implies x.(MemberAccess).targetIsThisInstance())
|
||||
or
|
||||
exists(int j | sameByStructure(x, y, i - 1) |
|
||||
sameInternal(getRankedChild(x, i, j), getRankedChild(y, i, j))
|
||||
)
|
||||
}
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameInternal(ControlFlowElement x, ControlFlowElement y) {
|
||||
sameByValue(x, y)
|
||||
or
|
||||
sameByStructure(x, y, getNumberOfActualChildren(x))
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if elements `x` and `y` structurally equal. `x` and `y` must be
|
||||
* flagged as candidates for structural equality, that is,
|
||||
* `candidate(x, y)` must hold.
|
||||
*/
|
||||
predicate same(ControlFlowElement x, ControlFlowElement y) {
|
||||
candidate(x, y) and
|
||||
sameInternal(x, y)
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* INTERNAL: Do not use.
|
||||
*
|
||||
* A verbatim copy of the class `StructuralComparisonConfiguration` for internal
|
||||
* use.
|
||||
*
|
||||
* A copy is needed in order to use structural comparison within the standard
|
||||
* library without running into caching issues.
|
||||
*/
|
||||
module Internal {
|
||||
// Import all uses of the internal library to make sure caching works
|
||||
private import semmle.code.csharp.controlflow.Guards as G
|
||||
|
||||
/**
|
||||
* A configuration for performing structural comparisons of program elements
|
||||
* (expressions and statements).
|
||||
*
|
||||
* The predicate `candidate()` must be overridden, in order to identify the
|
||||
* elements for which to perform structural comparison.
|
||||
*
|
||||
* Each use of the library is identified by a unique string value.
|
||||
*/
|
||||
abstract class InternalStructuralComparisonConfiguration extends string {
|
||||
bindingset[this]
|
||||
InternalStructuralComparisonConfiguration() { any() }
|
||||
|
||||
/**
|
||||
* Holds if elements `x` and `y` are candidates for testing structural
|
||||
* equality.
|
||||
*
|
||||
* Subclasses are expected to override this predicate to identify the
|
||||
* top-level elements which they want to compare. Care should be
|
||||
* taken to avoid identifying too many pairs of elements, as in general
|
||||
* there are very many structurally equal subtrees in a program, and
|
||||
* in order to keep the computation feasible we must focus attention.
|
||||
*
|
||||
* Note that this relation is not expected to be symmetric -- it's
|
||||
* fine to include a pair `(x, y)` but not `(y, x)`.
|
||||
* In fact, not including the symmetrically implied fact will save
|
||||
* half the computation time on the structural comparison.
|
||||
*/
|
||||
abstract predicate candidate(ControlFlowElement x, ControlFlowElement y);
|
||||
|
||||
private predicate candidateInternal(ControlFlowElement x, ControlFlowElement y) {
|
||||
candidate(x, y)
|
||||
or
|
||||
exists(ControlFlowElement xParent, ControlFlowElement yParent, int i |
|
||||
candidateInternalChild(xParent, i, x, yParent)
|
||||
|
|
||||
y = yParent.getChild(i)
|
||||
)
|
||||
}
|
||||
|
||||
pragma[noinline]
|
||||
private predicate candidateInternalChild(
|
||||
ControlFlowElement x, int i, ControlFlowElement xChild, ControlFlowElement y
|
||||
) {
|
||||
candidateInternal(x, y) and
|
||||
xChild = x.getChild(i)
|
||||
}
|
||||
|
||||
private predicate sameByValue(Expr x, Expr y) { sameByValueAux(x, y, y.getValue()) }
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameByValueAux(Expr x, Expr y, string value) {
|
||||
candidateInternal(x, y) and
|
||||
value = x.getValue()
|
||||
}
|
||||
|
||||
private ControlFlowElement getRankedChild(ControlFlowElement cfe, int rnk, int i) {
|
||||
(candidateInternal(cfe, _) or candidateInternal(_, cfe)) and
|
||||
i =
|
||||
rank[rnk](int j |
|
||||
exists(ControlFlowElement child | child = cfe.getChild(j) |
|
||||
not (j = -1 and cfe.(MemberAccess).targetIsThisInstance())
|
||||
)
|
||||
) and
|
||||
result = cfe.getChild(i)
|
||||
}
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameByStructure0(
|
||||
ControlFlowElement x, ControlFlowElement y, int elementKind, int children
|
||||
) {
|
||||
candidateInternal(x, y) and
|
||||
elementKind = elementKind(x) and
|
||||
children = getNumberOfActualChildren(x) and
|
||||
not (x.(Expr).hasValue() and y.(Expr).hasValue())
|
||||
}
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameByStructure(ControlFlowElement x, ControlFlowElement y, int i) {
|
||||
i = 0 and
|
||||
// At least one of `x` and `y` must not have a value, they must have
|
||||
// the same kind, and the same number of children
|
||||
sameByStructure0(x, y, elementKind(y), getNumberOfActualChildren(y)) and
|
||||
// If one of them has a reference attribute, they should both reference
|
||||
// the same node
|
||||
(exists(referenceAttribute(x)) implies referenceAttribute(x) = referenceAttribute(y)) and
|
||||
// x is a member access on `this` iff y is
|
||||
(x.(MemberAccess).targetIsThisInstance() implies y.(MemberAccess).targetIsThisInstance()) and
|
||||
(y.(MemberAccess).targetIsThisInstance() implies x.(MemberAccess).targetIsThisInstance())
|
||||
or
|
||||
exists(int j | sameByStructure(x, y, i - 1) |
|
||||
sameInternal(getRankedChild(x, i, j), getRankedChild(y, i, j))
|
||||
)
|
||||
}
|
||||
|
||||
pragma[nomagic]
|
||||
private predicate sameInternal(ControlFlowElement x, ControlFlowElement y) {
|
||||
sameByValue(x, y)
|
||||
or
|
||||
sameByStructure(x, y, getNumberOfActualChildren(x))
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if elements `x` and `y` structurally equal. `x` and `y` must be
|
||||
* flagged as candidates for structural equality, that is,
|
||||
* `candidate(x, y)` must hold.
|
||||
*/
|
||||
predicate same(ControlFlowElement x, ControlFlowElement y) {
|
||||
candidate(x, y) and
|
||||
sameInternal(x, y)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user