Miguel Raz Guzmán Macedo miguelraz

Rust Fundamentals

Overview

Writing Safe Rust gets you the following benefits instantly:
- running UBSAN, ASAN, THREADSAN and RAII analysis at compile time, without the performance penalty at runtime
- all bindings are consted by default unless they specifically opt out with let mut
- all code you depend on is also analyzed under the same constraints by the compiler
C++ copies variables by default, Rust transfers ownership (moves) by default. Custom types may opt into implicit Copy or explicit Clone copy semantics.

Cheatsheet for Julians

Why Learning Rust for Julia people in particular is special:

We already have many features that aren't a new sale: safety and performance through a fast GC, standard memory semantics that have mechanical sympathy coupled with a powerful JIT, a modern package manager, a unit testing framework, metaprogramming, and a documentation system.
When reaching for Rust is justified (resource constrained environments like embedded, cloud infrastructure or data bases, etc.) Julians have to go straight for FFI, erasing many of the boons of Safe Rust and dealing very quickly with unsafe code. This is topic is not the promising experience for beginners in the language.
Julians are used to thinking about memory footprint and layout in perf-sensitive code, as well as subtyping relations - two lynchpins for understanding the ownership and borrowsing system where the role of subtyping and variance are very commonly ommitted. This topic can therefore be explained much clearer and earlie

Rust Speed Optimizations

From setting core_affinity to measuring L1i cache misses with good ol' perf or poking at hardware counters, if there's standard perf tooling you expect to work, it should work well in Rust too (but it might look a bit different than what you expect.)

The Rust community has a healthy suite of monitoring for hundreds of perf mentrics, see perf.rust-lang.org.

Let's look at some Rust specific flavors of what you should know.

Prior training material art

Very rough sketch!

way more mini exercises

loopy vs iterator way
factorial and add
- 1 to 100 elems
collect all evens
any
all
fold, scan, reduce, flatten_map, tree_fold1
partition, partition_in_place, (COMPARE to C++)

	mrg@LAPTOP-F1SH43QJ:~$ dust .
	1.2G ┌── stable-x86_64-unknown-linux-gnu │ █████ │ 6%
	1.2G ┌─┴ toolchains │ █████ │ 6%
	1.2G ┌─┴ .rustup │ █████ │ 6%
	1.6G │ ┌── index.crates.io-6f17d22bba15001f│ ░▒██████ │ 8%
	1.6G │ ┌─┴ src │ ░▒██████ │ 8%
	1.8G │ ┌─┴ registry │ ░███████ │ 9%
	2.0G ├─┴ .cargo │ ████████ │ 10%
	863M │ ┌── stage0-std │

	I[23:39:28.282] clangd version 16.0.2 (https://github.com/llvm/llvm-project 18ddebe1a1a9bde349441631365f0472e9693520)
	I[23:39:28.283] Features: windows+grpc
	I[23:39:28.283] PID: 23980
	I[23:39:28.283] Working directory: \\wsl.localhost\Ubuntu\home\mrg\llvm-project
	I[23:39:28.283] argv[0]: c:\Users\mrg\AppData\Roaming\Code\User\globalStorage\llvm-vs-code-extensions.vscode-clangd\install\16.0.2\clangd_16.0.2\bin\clangd.exe
	I[23:39:28.283] argv[1]: --clang-tidy
	I[23:39:28.283] argv[2]: --compile-commands-dir=\\wsl.localhost\Ubuntu\home\mrg\llvm-project\build
	I[23:39:28.295] Starting LSP over stdin/stdout
	I[23:39:28.296] <-- initialize(0)
	I[23:39:28.363] --> reply:initialize(0) 67 ms

	[I] mrg@pop-os ~/o/LoopModels (bumprealloc) [1]> UBSAN_OPTIONS='print_stacktrace=1' cmake --build buildgcc/test
	[0/2] Re-checking globbed directories...
	[1/11] Clearing out old coverage data.
	[2/11] Building CXX object CMakeFiles/LoopModelsTests.dir/graph_test.cpp.o
	FAILED: CMakeFiles/LoopModelsTests.dir/graph_test.cpp.o
	/home/mrg/opt/GNAT/2021/bin/g++ -I/home/mrg/oss/LoopModels/test/../include -I/usr/lib/llvm-15/include -I/home/mrg/oss/LoopModels/buildgcc/test/_deps/unordered_dense-src/include -isystem /home/mrg/oss/LoopModels/buildgcc/test/_deps/googletest-src/googletest/include -isystem /home/mrg/oss/LoopModels/buildgcc/test/_deps/googletest-src/googletest -fno-omit-frame-pointer -fsanitize=address,undefined -g -fno-exceptions -fno-omit-frame-pointer -fmax-errors=8 -fconcepts-diagnostics-depth=4 -fno-semantic-interposition -fdiagnostics-color=always -Wall -Wpedantic -Wextra -Wshadow -D_GLIBCXX_ASSERTIONS -O0 -g --coverage -std=gnu++2a -Winvalid-pch -include /home/mrg/oss/LoopModels/buildgcc/test/CMakeFil

	cmake -G Ninja -DLLVM_TARGETS_TO_BUILD="X86" \
	-DCMAKE_BUILD_TYPE="Debug" \
	-DBUILD_SHARED_LIBS=ON \
	-DLLVM_USE_SPLIT_DWARF=OFF \
	-DLLVM_USE_LINKER=lld \
	-DLLVM_OPTIMIZED_TABLEGEN=ON \
	-DCMAKE_C_COMPILER="/usr/lib/ccache/clang" \
	-DLLVM_PARALLEL_LINK_JOBS="8" \
	-DLLVM_PARALLEL_COMPILE_JOBS="8" \
	-DCMAKE_CXX_COMPILER="/usr/lib/ccache/clang++" \

	julia> using GLMakie
	[ Info: Precompiling GLMakie [e9467ef8-e4e7-5192-8a1a-b1aee30e663a]
	libGL error: MESA-LOADER: failed to open radeonsi: /usr/lib/dri/radeonsi_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
	libGL error: failed to load driver: radeonsi
	libGL error: MESA-LOADER: failed to open radeonsi: /usr/lib/dri/radeonsi_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
	libGL error: failed to load driver: radeonsi
	libGL error: MESA-LOADER: failed to open swrast: /usr/lib/dri/swrast_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
	libGL error: failed to load driver: swrast
	┌ Warning: GLFW couldn't create an OpenGL window.
	│ This likely means, you don't have an OpenGL capable Graphic Card,