dim d07708df70 Connect libclang_rt to the build, for specific architectures. This
contains the libraries for Address Sanitizer (asan), Undefined Behavior
Sanitizer (ubsan) and Profile Guided Optimization.

ASan is a fast memory error detector. It can detect the following types
of bugs:

    Out-of-bounds accesses to heap, stack and globals
    Use-after-free
    Use-after-return (to some extent)
    Double-free, invalid free
    Memory leaks (experimental)

Typical slowdown introduced by AddressSanitizer is 2x.

UBSan is a fast and compatible undefined behavior checker. It enables a
number of undefined behavior checks that have small runtime cost and no
impact on address space layout or ABI.

PLEASE NOTE: the sanitizers still have some rough edges on FreeBSD,
particularly on i386.  These will hopefully be smoothed out in the
coming time.

Differential Revision: https://reviews.freebsd.org/D1505
2015-01-13 19:54:47 +00:00
..
2011-01-19 20:16:47 +00:00

$FreeBSD$

Note: If you modify these files, please keep hier(7) updated!

These files are used to create empty file hierarchies for building the
system into.  Some notes about working with them are placed here to try
and keep them in good working order.

    a)  The files use 4 space indentation, and other than in the header
        comments, should not contain any tabs.  An indentation of 4 is
        preferable to the standard indentation of 8 because the indentation
        of levels in these files can become quite deep causing the line to
        overflow 80 characters.

        This also matches with the files generated when using the
        mtree -c option, which was implemented that way for the same reason.

    b)  Only directories should be listed here.

    c)  The listing should be kept in filename sorted order.

    d)  Sanity checking changes to these files can be done by following
        this procedure (the sed -e is ugly, but fixing mtree -c to
        not emit the trailing white space would be even uglier):

            mkdir /tmp/MTREE
            mtree -deU -f BSD.X.dist -p /tmp/MTREE
            mtree -cdin -k uname,gname,mode -p /tmp/MTREE | \
		sed -e 's/ *$//' >BSD.X.new
            diff -u BSD.X.dist BSD.X.new
            rm -r /tmp/MTREE

        Note that you will get some differences about /set lines,
        and uname= gname= on certain directory areas, mainly man page
        sections.  This is caused by mtree not having a look ahead
        mechanism for making better selections for these as it
        traverses the hierarchy.

        The BSD.X.new file should NOT be committed, as it will be missing
        the correct header, and important keywords like ``nochange''.
        Simply use the diff for a sanity check to make sure things are in
        the correct order and correctly indented.

    e)  Further sanity checking of the system builds with DESTDIR=/someplace
        are more complicated, but can often catch missing entries in these
        files.  I tend to run this more complete sanity check shortly after
        the target date for a new release is announced.

        If you want details on it bug me about it via email to
        rgrimes@FreeBSD.org.