Rust Learning Path: Low-Level Semantics Focus

Phase 1: Foundations (2-3 weeks)

Core Language Basics

• Variables, mutability, and shadowing
• Primitive types and their memory representations
• Functions, control flow, and pattern matching
• Modules and project structure with Cargo

Start Here:

• The Rust Book (chapters 1-6)
• Practice with small CLI programs

Phase 2: Ownership & Memory Model (3-4 weeks)

Deep Dive into Ownership

• Stack vs heap allocation
• Move semantics and Copy trait
• Borrowing rules and the borrow checker
• Lifetimes and lifetime annotations
• Reference types and their costs

Low-Level Focus:

• Understanding std::mem::size_of and memory layout
• Drop trait and RAII patterns
• Interior mutability (Cell, RefCell)
• Zero-cost abstractions concept

Resources:

• Rust Book chapters 4, 10, 15
• "Visualizing Memory Layout of Rust's Data Types" blog posts
• Practice: Implement data structures from scratch (linked list, vector)

Phase 3: Unsafe Rust & FFI (2-3 weeks)

Understanding Unsafe

• Raw pointers and pointer arithmetic
• Unsafe superpowers and guarantees
• Calling C code (FFI)
• Writing safe abstractions over unsafe code

Projects:

• Create FFI bindings to a C library
• Implement a custom allocator
• Build unsafe data structures (intrusive linked list)

Resources:

• Rust Book chapter 19
• The Rustonomicon (start reading)

Phase 4: Advanced Memory & Concurrency (3-4 weeks)

Memory Deep Dive

• std::mem functions (transmute, forget, ManuallyDrop)
• Understanding Pin and Unpin
• Custom smart pointers
• Memory ordering and atomics

Concurrency Model

• Send and Sync traits
• Arc, Mutex, and atomic reference counting
• Lock-free data structures
• Thread safety guarantees

Resources:

• The Rustonomicon (complete)
• "Programming Rust" by Blandy & Orendorff (chapters on concurrency)

Phase 5: Performance & Optimization (2-3 weeks)

Low-Level Performance

• Understanding LLVM IR generation
• Inline assembly
• SIMD operations
• Profiling and benchmarking
• Reading generated assembly (cargo asm)

Projects:

• Optimize hot paths in real code
• Write SIMD-accelerated algorithms
• Benchmark different approaches

Phase 6: Systems Programming (Ongoing)

Advanced Topics

• Custom allocators and allocator APIs
• Async/await internals and Future trait
• Procedural macros
• Building OS components or embedded systems

Project Ideas:

• Write a memory allocator
• Build a simple kernel or bootloader
• Create embedded firmware (no_std)
• Implement a virtual machine or interpreter

Essential Resources

Books:

• The Rust Programming Language (The Book)
• The Rustonomicon (unsafe Rust)
• Rust for Rustaceans by Jon Gjengset
• Programming Rust by Blandy & Orendorff

Online:

• Rust compiler development guide
• Jon Gjengset's YouTube channel (Crust of Rust series)
• Fasterthanlime's blog posts
• "Learn Rust With Entirely Too Many Linked Lists"

Practice:

• Implement standard library components from scratch
• Contribute to systems-level crates
• Read source code: tokio, servo, ripgrep

Weekly Practice Routine

1. Read theory (1-2 hours)
2. Code exercises (2-3 hours)
3. Analyze assembly output of your code (30 min)
4. Deep dive into one standard library type's implementation (1 hour)
5. Experiment with unsafe code in controlled environment (1 hour)

Key Mindsets

• Always ask: "What's happening in memory?"
• Read compiler error messages carefully—they teach ownership
• Use tools: cargo expand, cargo asm, cargo miri
• Don't fear unsafe, but respect it
• Understand the "zero-cost abstraction" principle