This PR replaces three independent name demangling implementations
(Lean, C++, Python) with a single source of truth in
`Lean.Compiler.NameDemangling`. The new module handles the full
pipeline: prefix parsing (`l_`, `lp_`, `_init_`, `initialize_`,
`lean_apply_N`, `_lean_main`), postprocessing (suffix flags, private
name stripping, hygienic suffix stripping, specialization contexts),
backtrace line parsing, and C exports via `@[export]`.
The C++ runtime backtrace handler now calls the Lean-exported functions
instead of its own 792-line reimplementation. This is safe because
`print_backtrace` is only called from `lean_panic_impl` (soft panics),
not `lean_internal_panic`.
The Python profiler demangler (`script/profiler/lean_demangle.py`) is
replaced with a thin subprocess wrapper around a Lean CLI tool,
preserving the `demangle_lean_name` API so downstream scripts work
unchanged.
**New files:**
- `src/Lean/Compiler/NameDemangling.lean` — single source of truth (483
lines)
- `tests/lean/run/demangling.lean` — comprehensive tests (281 lines)
- `script/profiler/lean_demangle_cli.lean` — `c++filt`-style CLI tool
**Deleted files:**
- `src/runtime/demangle.cpp` (792 lines)
- `src/runtime/demangle.h` (26 lines)
- `script/profiler/test_demangle.py` (670 lines)
Net: −1,381 lines of duplicated C++/Python code.
🤖 Prepared with Claude Code
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
This PR adds tooling for profiling Lean programs with human-readable
function names in Firefox Profiler:
- **`script/lean_profile.sh`** — One-command pipeline: record with
samply, symbolicate, demangle, and open in Firefox Profiler
- **`script/profiler/lean_demangle.py`** — Faithful port of
`Name.demangleAux` from `NameMangling.lean`, with a postprocessor that
folds compiler suffixes into compact annotations (`[λ, arity↓]`, `spec
at context[flags]`)
- **`script/profiler/symbolicate_profile.py`** — Resolves raw addresses
via samply's symbolication API
- **`script/profiler/serve_profile.py`** — Serves demangled profiles to
Firefox Profiler without re-symbolication
- **`PROFILER_README.md`** — Documentation including a guide to reading
demangled names
### Example output in Firefox Profiler
| Raw C symbol | Demangled |
|---|---|
| `l_Lean_Meta_Sym_main` | `Lean.Meta.Sym.main` |
| `l_Lean_Meta_foo___redArg___lam__0` | `Lean.Meta.foo [λ, arity↓]` |
| `l_Lean_MVarId_withContext___at__...___spec__2___boxed` |
`Lean.MVarId.withContext [boxed] spec at Lean.Meta.bar[λ, arity↓]` |
Example:
<img width="1145" height="570" alt="image"
src="https://github.com/user-attachments/assets/8d23cc6a-1b89-4c60-9f4a-9f9f0f6e7697"
/>
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
