Priroda

Priroda is a step-through debugger for Rust programs running under Miri.

Current focus:

simple CLI prototype
single-threaded stepping with Miri's interpreter
source-location output after stepping
source-location breakpoint prototype
source-local listing prototype
runtime local state and value rendering
range-limited byte output for indirect locals

Setup

From miri/, install the pinned toolchain and the local cargo-miri command:

./miri toolchain
./miri install

Then build the Miri sysroot and export it for Priroda:

cargo +miri miri setup
export MIRI_SYSROOT="$(cargo +miri miri setup --print-sysroot)"

Run

Priroda currently reads MIRI_SYSROOT directly. After setup, run Priroda from miri/priroda/:

cargo run -- ../tests/pass/empty_main.rs

Test

Priroda's CLI tests also need MIRI_SYSROOT. Run them from miri/priroda/:

cargo test

If the CLI tests fail due to mismatched output, you can update the expected output files by running the tests with the --bless flag:

cargo test -- --bless

RUSTC_BLESS=1 cargo test

Commands

Command	Description
Enter, `si`, `stepi`	Execute one Miri interpreter step.
`s`, `step`	Step until the displayed source location changes.
`c`, `continue`	Continue until the program finishes or reaches a breakpoint.
`b <path>:<line>`, `break <path>:<line>`	Add a source-location breakpoint.
`l`, `locals`	List source-level locals in the current frame by name.
`p <local>`, `print <local>`	Print one MIR local by numeric id.
`f <alloc> <offset>`, `follow <alloc> <offset>`	Render allocation bytes from an offset, including the full allocation size.
`q`, `quit`	Exit Priroda.

Value Output

Immediate values use Miri's Immediate display representation. Indirect locals are rendered as the bytes belonging to the current value range, not as the entire backing allocation:

[01 02 03]
[?? ?? ??]

?? means the byte is uninitialized. A value whose runtime size cannot be determined is reported as <unsupported-unsized>.

Pointer/provenance spans are planned as part of the raw byte output, using a compact dump-like marker such as:

[<ptr alloc5+0> 2a 00 00 00]

Automatic pointer following is future work and should be explicit, not part of ordinary value printing. Typed field rendering and dereference/projection-aware printing are also future work.

EOF also exits Priroda cleanly.

Example:

(priroda) break tests/pass/empty_main.rs:3
(priroda) continue