var2addr

Extract global variable RAM locations from an ELF file's DWARF debug info and list them in a human-readable way — with struct and class members expanded to their absolute addresses:

PATH                       ADDRESS  TYPE         SIZE  DECL FILE
g_motor                 0x00009030  MotorData      12  test_firmware.c
g_motor.current         0x00009030  float           4  test_firmware.c
g_motor.voltage         0x00009034  float           4  test_firmware.c
g_motor.rpm             0x00009038  int32_t         4  test_firmware.c
g_system.motor.current  0x0000903c  float           4  test_firmware.c

Typical use: embedded debugging and tracing workflows where you need the exact RAM address of g_globalData.field2 to peek/poke/sample it over SWD/JTAG.

Features

• DWARF 4 and 5, GCC and Clang output
• C: globals, file-scope statics (with cross-TU collision disambiguation as file.c::name), nested structs, unions, enums, arrays
• C++: namespaces, class static data members, inheritance (base-class members flattened into the derived layout), template instantiations
• Rust (best-effort): module-qualified statics, payload-carrying enums
• Output as aligned table (default), JSON, CSV, or IAR-style MRD (X:2005A3B3H MyVariable … 0x2)
• Filter by substring, or resolve a single dotted path like g_system.motor.rpm

Install / Build

Requires Rust 1.85+ (edition 2024). Works on Linux, Windows, and macOS — pure Rust, no native dependencies.

cargo build --release
# binary: target/release/var2addr  (.exe on Windows)

Or install into your cargo bin dir:

cargo install --path .

Usage

# Full listing (table)
var2addr firmware.elf

# Only paths containing "motor"
var2addr firmware.elf --filter motor

# One variable in detail
var2addr firmware.elf --resolve g_system.motor.rpm

# Machine-readable
var2addr firmware.elf --format json
var2addr firmware.elf --format csv -o variables.csv

# IAR-style MRD file
var2addr firmware.elf --format mrd -o firmware.mrd

Exit codes: 0 success, 1 runtime error (no debug info, variable not found, …), 2 usage error.

Full documentation lives in docs/ (MkDocs):

cd docs && mkdocs serve

Notes & limitations

• Arrays are listed as one row with base address, element type and count (uint16_t[8]) — elements are not expanded individually.
• Variables without a fixed address (optimized out, register-allocated, location lists) are reported as errors when resolved directly and omitted from listings.
• Virtual C++ base classes are skipped (vtable-relative, not statically resolvable).
• The ELF must be compiled with -g (any optimization level works, but higher levels optimize more variables out).

Provenance

The ELF/DWARF parsing core is vendored from the debug_tracing_tool project (crates elf-parser and variable-model, commit 663861d3), stripped of its frontend/TypeScript bindings and adapted into a standalone CLI. MSRV 1.85.