Analyzing the Linker Map file with a little help from the ELF and the DWARF

Analyzing the Linker Map file with a little help from the ELF and the DWARF

Govind Mukundan

Still RelevantIntermediate

When you're writing firmware, there always comes a time when you need to check the resources consumed by your efforts - perhaps because you're running out of RAM or Flash or you want to optimize something. The map file generated by your linker is...

Summary

This blog explains how to read and interpret the linker map file by correlating its contents with the ELF binary and DWARF debug information. Readers will learn practical techniques and tool commands to map addresses back to source, identify big consumers of Flash/RAM, and guide effective footprint optimizations.

Key Takeaways

Interpret the structure of a GNU linker map and relate entries to ELF sections and memory regions
Use DWARF debug info and tools (addr2line, dwarfdump) to map addresses back to source files and functions
Identify the largest consumers of Flash and RAM and spot dead or duplicated code/data
Apply toolchain commands (readelf, objdump, nm, size) to extract symbol, section, and size details
Improve linker scripts and placement strategies to reduce firmware footprint and optimize memory layout

Who Should Read This

Embedded firmware developers and engineers with some toolchain experience who need to analyze linker maps, debug memory/size issues, and optimize firmware footprint.

Still RelevantIntermediate