Sanitizers and Platform Support

While Miri interprets pure Rust MIR in a virtual machine, compiler sanitizers (such as AddressSanitizer, ThreadSanitizer, MemorySanitizer, and LeakSanitizer) instrument native machine code generated by LLVM so you can detect memory corruption and data races at near-native speed—including across C/C++ FFI boundaries that Miri cannot interpret.

When to Use Miri vs LLVM Sanitizers:

  Pure Rust `unsafe` Code (Pointers, MaybeUninit, Atomics):
    ---> Use `cargo +nightly miri test` (Catches Rust-specific Stacked/Tree Borrows UB!)

  Mixed Rust + C/C++ FFI (`extern "C"`, OS Syscalls, Native Libraries):
    ---> Use LLVM Sanitizers (`-Zsanitizer=address` / `thread` / `memory` / `leak`)

LLVM Sanitizers Supported by `rustc`

Sanitizer	`-Zsanitizer=<name>`	What It Detects at Runtime	Typical Slowdown
AddressSanitizer (ASan)	`address`	Out-of-bounds heap/stack/global accesses, use-after-free, double-free across Rust and C/C++ FFI.	~2x
ThreadSanitizer (TSan)	`thread`	Data races where two threads access the same memory location concurrently without synchronization.	~5x–10x
MemorySanitizer (MSan)	`memory`	Reads of uninitialized memory across Rust and C/C++ (requires rebuilding `std` via `-Zbuild-std`).	~3x
LeakSanitizer (LSan)	`leak`	Heap memory allocations that remain unreachable at process exit.	~1.1x
Hardware-Assisted ASan (HWASan)	`hwaddress`	Same as ASan using AArch64 top-byte-ignore (TBI) pointer tagging with lower RAM overhead.	~2x

# Run tests with AddressSanitizer on Linux or macOS (nightly compiler flag):
RUSTFLAGS="-Zsanitizer=address" cargo +nightly test --target x86_64-unknown-linux-gnu

# Run multi-threaded tests with ThreadSanitizer to detect data races:
RUSTFLAGS="-Zsanitizer=thread" cargo +nightly test --target aarch64-apple-darwin

Rust Target Tiers and Platform Support

Rust classifies every supported operating system and CPU architecture (target triple, structured as <arch>-<vendor>-<os>-<env>) into three official Support Tiers:

Support Tier	Automated CI Guarantees	Example Target Triples
Tier 1 ("Guaranteed to Work")	Official binary releases; every commit to `rust-lang/rust` must pass the full compiler and standard library test suite on that platform before merging.	`x86_64-unknown-linux-gnu`, `aarch64-unknown-linux-gnu`, `aarch64-apple-darwin`, `x86_64-pc-windows-msvc`
Tier 2 ("Guaranteed to Build")	Official binary releases (`rustup target add <triple>`); CI verifies that `std` and `core` compile cleanly on every commit, though full host test suites may not run on every PR.	`wasm32-unknown-unknown`, `wasm32-wasip1`, `x86_64-unknown-linux-musl`, `aarch64-linux-android`, `thumbv7em-none-eabihf`
Tier 3 ("Best-Effort Community Support")	Source support present in `rustc`, but not built automatically by official CI; requires building `core`/`std` locally via `cargo +nightly build -Zbuild-std`.	Retro/niche OSes and specialized microcontroller architectures

use std::env;

fn describe_host_platform() -> String {
    format!(
        "arch={}, os={}, family={}, pointer_width={}-bit",
        env::consts::ARCH,
        env::consts::OS,
        env::consts::FAMILY,
        usize::BITS
    )
}

fn main() {
    println!("Host platform: {}", describe_host_platform());
}

Host platform: arch=aarch64, os=macos, family=unix, pointer_width=64-bit

LLVM Sanitizers Supported by rustc

Rust Target Tiers and Platform Support

LLVM Sanitizers Supported by `rustc`