---
title: "Static analysis, MISRA C and stack usage"
---

# Static analysis, MISRA C and stack usage

Running Cppcheck with its MISRA C:2012 addon from the Editor, rule texts, recording deviations, the compliance summary, coding standards checks on save, and per-function stack usage from GCC.

Static analysis runs **Cppcheck** with its **MISRA C:2012 addon** and puts every finding in Problems at its line. Cppcheck is the analyser the module drives today; the vendor analysers are listed on [What's next](https://neuralinverse.com/docs/modules/embedded/whats-next/).

**Verification state:** unit-tested on Cppcheck XML output fixtures. The integration test against a real Cppcheck exists and has **not run in a verified audit**; no Cppcheck version is verified. On the Embedded Linux side, Cppcheck 2.13.0 with the MISRA addon has run on Linux (see [Embedded Linux](https://neuralinverse.com/docs/modules/embedded-linux/)).

## Requirements

- Cppcheck 2.10 or newer, found on `PATH` or through `neuralInverse.embedded.paths.cppcheck`.
- Python 3 that Cppcheck can run, for the MISRA addon.
- For guideline headlines and categories: a MISRA C:2012 rule texts file from **your own licensed copy** of MISRA C:2012. The texts are copyrighted by MISRA, so none ship with the Editor.

## Run it

| Command | What it does |
|---|---|
| **Run Static Analysis (Cppcheck, MISRA C:2012)** | Analyses the project, with the compile commands of the active build |
| **Run Static Analysis on Current File** | Analyses the open file |
| **Show MISRA C:2012 Compliance Summary** | The summary of the last project run: tool and version, date, violations per guideline, recorded deviations |
| **Clear Static Analysis Results** | Removes the findings from Problems |

![Cppcheck MISRA C:2012 findings in Problems and the compliance summary of the run.](https://neuralinverse.com/docs-images/modules/embedded/misra-cppcheck.webp)

Set `neuralInverse.embedded.analysis.onSave` to `true` to analyse each C or C++ source file of the project when it is saved.

## Settings

| Setting | Default | Meaning |
|---|---|---|
| `neuralInverse.embedded.analysis.misra` | `true` | Check the MISRA C:2012 guidelines (with amendments 1 and 2) that Cppcheck's addon supports |
| `neuralInverse.embedded.analysis.misraRuleTexts` | empty | Your rule texts file, in the format the addon reads (Appendix A as text), absolute or relative to the folder of `CMakePresets.json`. With it, mandatory findings show as errors, required as warnings, advisory as information |
| `neuralInverse.embedded.analysis.checks` | `warning`, `style`, `performance`, `portability` | Cppcheck check groups besides its error checks, which always run |
| `neuralInverse.embedded.analysis.suppressionsFile` | empty | Your approved deviations (below) |
| `neuralInverse.embedded.analysis.exclude` | `**/third_party/**` | Globs of files to skip, such as vendored code |
| `neuralInverse.embedded.analysis.onSave` | `false` | Analyse on save |

Without a rule texts file, guideline categories are unknown and the summary says so.

## Record approved deviations

Write deviations in a Cppcheck suppressions file and name it in `neuralInverse.embedded.analysis.suppressionsFile`. One `id[:file[:line]]` per line, with the rationale in `#` comments above it:

```text
# Deviation D-012, approved by the safety lead: the DMA descriptor cast is required by the hardware.
misra-c2012-11.5:drivers/dma.c
```

Deviations in the suppressions file are listed in the compliance summary. `cppcheck-suppress` comments in the source also work, but are not listed there.

## What the summary does and does not show

Cppcheck's MISRA addon does not check every guideline, and some guidelines cannot be decided by any tool. A guideline without violations in the summary is **not** shown to be complied with: record how each unchecked guideline is met before claiming compliance. The summary is evidence toward a MISRA C:2012 compliance argument; it is not a compliance claim.

## Coding standards on save

Three checks run on save, with findings in Problems under the source **Neural Inverse Embedded**:

| Check | Setting | Default |
|---|---|---|
| Every C, header and assembly file starts with your organisation's header (`{year}` stands for a year or range) | `neuralInverse.embedded.standards.requiredHeader` | Empty: not checked |
| No run-time allocation (`malloc`, `calloc`, `realloc`, `free`, `alloca`, `pvPortMalloc`, `vPortFree` and similar) in the folders listed | `neuralInverse.embedded.standards.noDynamicAllocationDirectories` | Empty: no folder checked |
| No `#pragma once`; guard headers with `#ifndef`, `#define` and `#endif` | | Always on |

`neuralInverse.embedded.standards.exclude` (default `third_party/**`, `build/**`, `out/**`) lists files these checks skip.

![Coding standards findings in Problems: a missing copyright header, dynamic allocation in a driver, and #pragma once in a header.](https://neuralinverse.com/docs-images/modules/embedded/coding-standards.webp)

State: unit-tested; the integration test exists and did not run in the audit.

## Stack usage

Build with GCC's `-fstack-usage`. The module reads the `.su` files and puts every function whose stack frame has no bound (a variable-length array or `alloca`) in Problems. Per-function frames also appear in the Firmware Memory editor.

This covers per-function frames from GCC, as STM32CubeIDE's Static Stack Analyzer does for each function. State: unit-tested on `.su` fixtures; GCC output from a real build is not verified.