Files
codeql/cpp/ql/lib/semmle/code/cpp/internal/Overlay.qll
2025-12-11 15:41:35 +01:00

81 lines
2.0 KiB
Plaintext

/**
* Defines entity discard predicates for C++ overlay analysis.
*/
private import OverlayXml
/**
* Holds always for the overlay variant and never for the base variant.
* This local predicate is used to define local predicates that behave
* differently for the base and overlay variant.
*/
overlay[local]
predicate isOverlay() { databaseMetadata("isOverlay", "true") }
overlay[local]
private string getLocationFilePath(@location_default loc) {
exists(@file file | locations_default(loc, file, _, _, _, _) | files(file, result))
}
/**
* Gets the file path for an element with a single location.
*/
overlay[local]
private string getSingleLocationFilePath(@element e) {
exists(@location_default loc |
var_decls(e, _, _, _, loc)
or
fun_decls(e, _, _, _, loc)
or
type_decls(e, _, loc)
or
namespace_decls(e, _, loc, _)
or
macroinvocations(e, _, loc, _)
or
preprocdirects(e, _, loc)
|
result = getLocationFilePath(loc)
)
}
/**
* Gets the file path for an element with potentially multiple locations.
*/
overlay[local]
private string getMultiLocationFilePath(@element e) {
exists(@location_default loc |
exists(@var_decl vd | var_decls(vd, e, _, _, loc))
or
exists(@fun_decl fd | fun_decls(fd, e, _, _, loc))
or
exists(@type_decl td | type_decls(td, e, loc))
or
exists(@namespace_decl nd | namespace_decls(nd, e, loc, _))
|
result = getLocationFilePath(loc)
)
}
/**
* A local helper predicate that holds in the base variant and never in the
* overlay variant.
*/
overlay[local]
private predicate holdsInBase() { not isOverlay() }
/**
* Discards an element from the base variant if:
* - It has a single location in a changed file, or
* - All of its locations are in changed files.
*/
overlay[discard_entity]
private predicate discardElement(@element e) {
holdsInBase() and
(
overlayChangedFiles(getSingleLocationFilePath(e))
or
forex(string path | path = getMultiLocationFilePath(e) | overlayChangedFiles(path))
)
}