When building `WITH_PYTHON`, where a global list of modules is maintained, deleting a module also erases the entry in said global list. This can lead to memory corruption if the global list is destructed before the module.
Using `on_shutdown()` instead means the module destructor is explicitly called before the global list can be destructed, preventing the issue.
Also add a comment to `Pass::~Pass()` to suggest the same for future passes that might try to use that (and see this commit in the blame if they need a reason why).
The lexer for liberty files was using istream's `get` and `unget` which
are notorious for bad performance and that showed up during profiling.
This replaces the direct `istream` use with a custom LibertyInputStream
that does its own buffering to provide `get` and `unget` that behave the
same way but are implemented with a fast path that is easy to inline and
optimize.
Instead, change the default `Design::selected_modules()` to match the behaviour (i.e. `selected_unboxed_modules_warn()`) because it's a lot of files to touch and they don't really _need_ to be updated.
Also change `Design::selected_whole_modules()` users over to `Design::selected_unboxed_whole_modules()`, except `attrmap` because I'm not convinced it should be ignoring boxes. So instead, leave the deprecation warning for that one use and come back to the pass another time.
Used to select all modules including boxes, set when both `full` and `boxes` are true in the constructor, pulling down `full_selection`.
Add `Selection::selects_all()` method as short hand for `full_selection || complete_selection`.
Update selection operations to account for complete selections.
Add static methods to `Selection` for creating a new empty/full/complete selection to make it clearer to users when doing so.
Use said static methods to replace most instances of the `Selection` constructor.
Update `Selection::optimize` to use
New methods on Design to push/pop selection instead of accessing the selection stack directly. Includes methods for pushing a full/complete/empty selection.
Also helper methods on modules to check `is_selected` and `is_selected_whole`.
