66 lines
2.5 KiB
Plaintext
66 lines
2.5 KiB
Plaintext
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$FreeBSD$
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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 currently aims to compile with g++ 4.2.1 and so doesn't make any
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use of C++11 features. It would be a good idea to relax this restriction once
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clang is the default compiler for ARM, MIPS and PowerPC.
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This code makes use of a lot of iterator loops, which would be cleaner using
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the new syntax in C++11. It also explicitly deletes a lot of objects held in
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collections in destructors that have these collections as their members. This
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could be simplified by using `shared_ptr`.
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The code does make use of `static_assert()`, but uses a macro in utility.hh to
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remove these if they are not supported. The FreeBSD standard headers also
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define a compatibility macro the implements static asserts in terms of an array
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with 1 element on success and -1 elements on failure.
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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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