This is the first step in replacing the std::vector of Instruction
pointers to using and intrusive linked list.
To this end, we created the InstructionList class. It inherites from
the IntrusiveList class, but add the extra concept of ownership. An
InstructionList owns the instruction that are in it. This is to be
consistent with the current ownership rules where the vector owns the
instruction that are in it.
The other larger change is that the inst_ member of the BasicBlock class
was changed to using the InstructionList class.
Added test for the InsertBefore functions, and making sure that the
InstructionList destructor will delete the elements that it contains.
I've also add extra comments to explain ownership a little better.
This commit is the initial implementation of the intrusive linked list
class. It includes the implementation in the header files, and unit
test.
The iterators are circular: incrementing end() gives begin() and
decrementing begin() gives end(). Also made it valid to
decrement end().
Expliticly defines move constructor and move assignment
- Visual Studio 2013 does not implicitly generate the move constructor or
move assignments. So they need to be explicit, otherwise it will try to
use the copy constructor, which we explicitly deleted.
- Can't use "= default" either.
Seems like VS2013 does not support explicitly using the default move
constructors and move assignments, so I wrote them out.
