While investigating a bug with `TInstruction` sharing, I discovered that we had a case where alias analysis could create two `VirtualVariable`s for the same `Allocation`. For an indirect parameter allocation, we were using the type of the pointer variable as the type of the indirect allocation, instead of just `Unknown`. If the `IRType` of the pointer variable was the same type as the type of at least one access to the indirect allocation, we'd create both an `EntireAllocationVirtualVariable` and a `VariableVirtualVariable` for the allocation.
I added a new consistency test to guard against this in the future. This also turned out to be the root cause of the one existing known consistency failure in the IR tests.
All these queries have been deprecated since 2018. There is
unfortunately no way to deprecate a library, but it's been years since
we populated any databases using the VCS library, so nobody should be
using it.
I took most of the docs from the corresponding predicates in
JavaScript's `CodeDuplication.qll`. Where JavaScript had a corresponding
predicate but didn't have QLDoc, I added new QLDoc to both.
The `cpp/too-few-arguments` query produced alerts for ambiguous
databases where a function had multiple possible declarations, with some
declarations having the right number of parameters and some having too
many. With this change, the query errs on the side of caution in those
cases and does not produce an alert.
This fixes false positives on racket/racket.
The new `hasDefiniteNumberOfParameters` is exactly the negation of the
old `hasZeroParamDecl`.
In a couple of cases, we use `glval<unknown>` as the result type of an instruction because we can't come up with anything better. Two examples are the result of `VariableAddress[#ellipsis]`, and the address of the temp variable that holds the lvalue result of the conditional operator in `(a ? b : c) = y`. In both cases, we call `getTypeForGLValue(any(UnknownType t))`, but that would have multiple results because `result.hasType(any(UnknownType t), true)` also holds for `CppFunctionGLValueType`. I tightened the result type to ensure we get the right one.
The QL compiler is about to be changed to emit a warning when overriding a deprecated predicate. This PR marks the existing overrides of deprecated predicates as `deprecated` themselves, which avoids the warning.
The `Print.qll` models seem to preserve the `isWideCharDefault()` predicate for backwards compatibility, so we can't remove them and must continue overriding them.
The `XML.qll` override is necessary because both superclasses declare the `getName()` predicate. One is `deprecated`, and the other is `abstract`, so we have to have an override.
