Notes for people hacking on dtc =============================== This file contains some notes for people wishing to hack on dtc. Upstreaming ----------- This code is developed in the git repository: https://github.com/davidchisnall/dtc If you got the source from anywhere else and wish to make changes, please ensure that you are working against the latest version, or you may end up fixing bugs that are already fixed upstream. Although the license makes no requirement that you share any improvements that you make, patches are very welcome. C++11 ----- This project uses C++11, as the goal for FreeBSD 11 is to require C/C++11 as a minimum, either from clang or an external toolchain. In particular, it uses `std::unique_ptr` extensively for memory management within the tree. Unique pointers are also used in several other places to track ownership. Most iterator loops use the new loop syntax and the `auto` type for type deduction. Range-based `for` loops generally improve the readability of the code, though `auto` should only be used in places where the type can be deduced as easily by the reader as by the compiler. The code also makes use of `static_assert()` to track compile-time invariants. Adding New Checks ----------------- Currently, the biggest weakness of this version of the tool is that it lacks most of the semantic checkers that can be implemented by simply reading the ePAPR spec. The `checker` class provides a simple superclass for implementing these quite easily. There are also helper methods on `device_tree` for finding specific nodes, for checks that require some understanding of the structure of the tree. We should probably add a parent pointer to the `node` class for easily walking up the tree. Adding Direct C Output ---------------------- The FreeBSD build system currently uses dtc to generate a blob and then converts this to C source code. A new `output_writer` subclass could easily generate the C directly. Parser Improvements ------------------- There are a few FIXME lines in the parser for some corner cases that are not currently used by FreeBSD. These are mainly related to labels in the middle of values. These can be fixed by creating a new `property_value` with the specified label, starting at the location of the label. Don't forget to remove the associated comments from the BUGS section of the man page if you fix this.