It's safe for a member function of a class or struct to call a function
or allocate a local variable with a pointer or a reference to a member
variable since "this" pointer, and therefore all its members, will be
kept alive by its caller so recognize as such.
This PR adds the support for recognizing calling adoptCF/adoptNS on the
result of a cast operation on the return value of a function which
creates NS or CF types. It also fixes a bug that we weren't reporting
memory leaks when CF types are created without ever calling RetainPtr's
constructor, adoptCF, or adoptNS.
To do this, this PR adds a new mechanism to report a memory leak
whenever create or copy CF functions are invoked unless this CallExpr
has already been visited while validating a call to adoptCF. Also added
an early exit when isOwned returns IsOwnedResult::Skip due to an
unresolved template argument.
This PR adds alpha.webkit.UnretainedLocalVarsChecker by generalizing
RawPtrRefLocalVarsChecker. It checks local variables to NS or CF types
are guarded with a RetainPtr or not. The new checker is effective for NS
and CF types in Objective-C++ code without ARC, and it's effective for
CF types in code with ARC.
In WebKit, we often write Foo::ensureBar function which lazily
initializes m_bar and returns a raw pointer or a raw reference to m_bar.
Such a return value is safe to use for the duration of a member function
call in Foo so long as m_bar is const so that it never gets unset or
updated with a new value once it's initialized.
This PR adds support for recognizing these types of functions and
treating its return value as a safe origin of a function argument
(including "this") or a local variable.
It's safe to have a raw pointer or a raw reference to a singleton
object. Explicitly allow this in UncountedLocalVarsChecker and
UncheckedLocalVarsChecker.
This PR introduces alpha.webkit.UncheckedLocalVarsChecker which detects
a raw reference or a raw pointer local, static, or global variable to a
CheckedPtr capable object without a guardian variable in an outer scope.
