c6d50eff8a
No functional change (in program code). Additional DWARF metadata is generated in the .eh_frame section. Also, it is now a compile-time requirement that machine/asm.h ENTRY() and END() macros are paired. (This is subject to ongoing discussion and may change.) This DWARF metadata allows llvm-libunwind to unwind program stacks when the program is executing the function. The goal is to collect accurate userspace stacktraces when programs have entered syscalls. (The motivation for "Call Frame Information," or CFI for short -- not to be confused with Control Flow Integrity -- is to sufficiently annotate assembly functions such that stack unwinders can unwind out of the local frame without the requirement of a dedicated framepointer register; i.e., -fomit-frame-pointer. This is necessary for C++ exception handling or collecting backtraces.) For the curious, a more thorough description of the metadata and some examples may be found at [1] and documentation at [2]. You can also look at 'cc -S -o - foo.c | less' and search for '.cfi_' to see the CFI directives generated by your C compiler. [1]: https://www.imperialviolet.org/2017/01/18/cfi.html [2]: https://sourceware.org/binutils/docs/as/CFI-directives.html Reviewed by: emaste, kib (with reservations) Differential Revision: https://reviews.freebsd.org/D22122 |
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|---|---|---|
| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .cirrus.yml | ||
| .clang-format | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| RELNOTES | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
Source Roadmap:
bin System/user commands.
cddl Various commands and libraries under the Common Development
and Distribution License.
contrib Packages contributed by 3rd parties.
crypto Cryptography stuff (see crypto/README).
etc Template files for /etc.
gnu Various commands and libraries under the GNU Public License.
Please see gnu/COPYING* for more information.
include System include files.
kerberos5 Kerberos5 (Heimdal) package.
lib System libraries.
libexec System daemons.
release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
sbin System commands.
secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
sys Kernel sources.
sys/<arch>/conf Kernel configuration files. GENERIC is the configuration
used in release builds. NOTES contains documentation of
all possible entries.
tests Regression tests which can be run by Kyua. See tests/README
for additional information.
tools Utilities for regression testing and miscellaneous tasks.
usr.bin User commands.
usr.sbin System administration commands.
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see:
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html