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The reference can be bound to an invalid object (*nullptr) in situations where no proper owner SimObject can be provided to the port constructor. This rightfully triggers a UBSAN warning. Also, these two classes do not make use of the owner reference member themselves and expose it as a protected member reference to subclasses. This desing has several drawbacks: requires the reference to owner to travel the class hierarchy up and down, loosing its true static type in the process ; non-private member variable should not be part of the API of such fundamental classes, if only for maintainability ; a reference bound from a nullable pointer is a lying API as it hides the optional aspect of ownership. Note that the reference to invalid object can't be properly fixed until the complete removal of the owner reference. This patch lays the path toward that fix. Change-Id: I8b42bc57d7826656726f7708492c43366f20633a Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67551 Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu> Tested-by: kokoro <noreply+kokoro@google.com> Maintainer: Bobby Bruce <bbruce@ucdavis.edu> Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/about, and for more information about building the simulator and getting started please see http://www.gem5.org/documentation and http://www.gem5.org/documentation/learning_gem5/introduction. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/documentation/general_docs/building for more details concerning the minimum versions of these tools. Once you have all dependencies resolved, type 'scons build/<CONFIG>/gem5.opt' where CONFIG is one of the options in build_opts like ARM, NULL, MIPS, POWER, SPARC, X86, Garnet_standalone, etc. This will build an optimized version of the gem5 binary (gem5.opt) with the the specified configuration. See http://www.gem5.org/documentation/general_docs/building for more details and options. The main source tree includes these subdirectories: - build_opts: pre-made default configurations for gem5 - build_tools: tools used internally by gem5's build process. - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - include: include files for use in other programs - site_scons: modular components of the build system - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you may need compiled system firmware, kernel binaries and one or more disk images, depending on gem5's configuration and what type of workload you're trying to run. Many of those resources can be downloaded from http://resources.gem5.org, and/or from the git repository here: https://gem5.googlesource.com/public/gem5-resources/ If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.