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