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The "Regs" structure in the DynInst class was using placement new to allocate register arrays in a dynamically allocated blob which can be resized based on the number of source and destination registers. Unfortunately, it was assumed that the alignment of the components of that structure would work out because they were ordered from largest to smallest, which should imply largest alignment to smallest. This change instead uses an overloaded new operator to allocate extra memory for the DynInst itself, and then initialize arrays within that extra space. The DynInst class then gets pointers to the arrays so it can access them. This has the benefit that only one chunk of memory is allocated, instead of one for the DynInst and then a second for the arrays. Also, this new version uses the alignof operator to figure out what alignment is needed for each array, which should avoid any undefined behavior. The new-ing, initialization, destructing, and delete-ing are also more carefully orchestrated. Hopefully one or both of these will squash potential memory management bugs. Change-Id: Id2fa090b53909f14a8cb39801e9930d4608e42f7 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52485 Reviewed-by: Gabe Black <gabe.black@gmail.com> Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br> Maintainer: Gabe Black <gabe.black@gmail.com> Tested-by: kokoro <noreply+kokoro@google.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.