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codeql/cpp/ql/lib/semmle/code/cpp/internal/ResolveClass.qll
2022-06-23 09:05:32 +00:00

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import semmle.code.cpp.Type
/** For upgraded databases without mangled name info. */
pragma[noinline]
private string getTopLevelClassName(@usertype c) {
not mangled_name(_, _) and
isClass(c) and
usertypes(c, result, _) and
not namespacembrs(_, c) and // not in a namespace
not member(_, _, c) and // not in some structure
not class_instantiation(c, _) // not a template instantiation
}
/**
* For upgraded databases without mangled name info.
* Holds if `d` is a unique complete class named `name`.
*/
pragma[noinline]
private predicate existsCompleteWithName(string name, @usertype d) {
not mangled_name(_, _) and
is_complete(d) and
name = getTopLevelClassName(d) and
onlyOneCompleteClassExistsWithName(name)
}
/** For upgraded databases without mangled name info. */
pragma[noinline]
private predicate onlyOneCompleteClassExistsWithName(string name) {
not mangled_name(_, _) and
strictcount(@usertype c | is_complete(c) and getTopLevelClassName(c) = name) = 1
}
/**
* For upgraded databases without mangled name info.
* Holds if `c` is an incomplete class named `name`.
*/
pragma[noinline]
private predicate existsIncompleteWithName(string name, @usertype c) {
not mangled_name(_, _) and
not is_complete(c) and
name = getTopLevelClassName(c)
}
/**
* For upgraded databases without mangled name info.
* Holds if `c` is an incomplete class, and there exists a unique complete class `d`
* with the same name.
*/
private predicate oldHasCompleteTwin(@usertype c, @usertype d) {
not mangled_name(_, _) and
exists(string name |
existsIncompleteWithName(name, c) and
existsCompleteWithName(name, d)
)
}
pragma[noinline]
private @mangledname getClassMangledName(@usertype c) {
isClass(c) and
mangled_name(c, result)
}
/** Holds if `d` is a unique complete class named `name`. */
pragma[noinline]
private predicate existsCompleteWithMangledName(@mangledname name, @usertype d) {
is_complete(d) and
name = getClassMangledName(d) and
onlyOneCompleteClassExistsWithMangledName(name)
}
pragma[noinline]
private predicate onlyOneCompleteClassExistsWithMangledName(@mangledname name) {
strictcount(@usertype c | is_complete(c) and getClassMangledName(c) = name) = 1
}
/** Holds if `c` is an incomplete class named `name`. */
pragma[noinline]
private predicate existsIncompleteWithMangledName(@mangledname name, @usertype c) {
not is_complete(c) and
name = getClassMangledName(c)
}
/**
* Holds if `c` is an incomplete class, and there exists a unique complete class `d`
* with the same name.
*/
private predicate hasCompleteTwin(@usertype c, @usertype d) {
exists(@mangledname name |
existsIncompleteWithMangledName(name, c) and
existsCompleteWithMangledName(name, d)
)
}
import Cached
cached
private module Cached {
/**
* If `c` is incomplete, and there exists a unique complete class with the same name,
* then the result is that complete class. Otherwise, the result is `c`.
*/
cached
@usertype resolveClass(@usertype c) {
hasCompleteTwin(c, result)
or
oldHasCompleteTwin(c, result)
or
not hasCompleteTwin(c, _) and
not oldHasCompleteTwin(c, _) and
result = c
}
/**
* Holds if `t` is a struct, class, union, or template.
*/
cached
predicate isClass(@usertype t) {
usertypes(t, _, 1) or
usertypes(t, _, 2) or
usertypes(t, _, 3) or
usertypes(t, _, 6) or
usertypes(t, _, 10) or
usertypes(t, _, 11) or
usertypes(t, _, 12)
}
cached
predicate isType(@type t) {
not isClass(t)
or
t = resolveClass(_)
}
}