63 lines
2.3 KiB
Plaintext
63 lines
2.3 KiB
Plaintext
|
|
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.
|