values the same way it treats null pointers. This is needed to allow
CallbackVH to be used as a key in a DenseMap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77695 91177308-0d34-0410-b5e6-96231b3b80d8
to make the copy constructor and destructor protected, and corresponding
adjustments to the unittests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70644 91177308-0d34-0410-b5e6-96231b3b80d8
the comparison operators were not only unnecessary in the presence of the
implicit conversion; they caused ambiguous overload errors. So I deleted them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70243 91177308-0d34-0410-b5e6-96231b3b80d8
which are effectively smart pointers to Value*'s. They are both very light
weight and simple, and react to values being destroyed or being RAUW'd.
WeakVN does a best effort to follow a value around, including through RAUW
operations and will get nulled out of the value is destroyed. This is useful
for the eventual "metadata that references a value" work, because it is a
reference to a value that does not show up on its use_* list.
AssertingVH is a pointer that compiles down to a dumb raw pointer when
assertions are disabled. When enabled, it emits an assertion if the
pointed-to value is destroyed while it is still being referenced. This
is very useful for Maps and other things, and should have caught the recent
bugs in CallGraph and Reassociate, for example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68149 91177308-0d34-0410-b5e6-96231b3b80d8
