Add command line options to reporting tool

Introduction

This proposal looks at adding command line options to customise the functionality of the footprint reporting tools.

Problem description

Currently, there are no customisation options when running west build -t rom_report/west build -t ram_report.

Proposed change

This proposal considers options to add the ability for the end user to tweak the output to their desires. My current ideas for the options are:

making report depth a configurable parameter
- this is already an argument in a lower-level script, but not available from west build
allowing the sort key of the report to be changed from alphabetical to size
- considering that ROM reports will be used to view which parts of the code are taking up the most space, it makes sense to be able to sort the output by size, rather than by name.
Any other suggestions welcome!

Detailed RFC

Proposed change (Detailed)

This change looks to leverage the structure of cmake/reports/CMakeLists.txt and scripts/footprint/size_report to introduce the new features:

The report script scripts/footprint/size_report is already designed to take command line arguments, including the depth parameter. The proposal also considers adding a sort key option, as well as any other options suggested by the community.

However, the tool is best used via the west build command as the cmake file loads in many of the other required arguments, and so modifications should also be made to the cmake/reports/CMakeLists.txt file.

With the proposed changes, a report might be generated like the following:

West build -t rom_report -Dsort_key=size

As a note, I have tried these changes by manually changing lines in the scripts and found them to work as expected.

Dependencies

This is a focussed change, and only affects cmake/reports/CMakeLists.txt and scripts/footprint/size_report

Concerns and Unresolved Questions

Main question point is that there needs to be a determination of which options to support and how they should be named.

Alternatives

Main alternative was to change the default sorting behaviour of the report, but that might break other people's workflows.

zephyrproject-rtos / zephyr