| Bug Category | Description | Automotive Example |
|---|---|---|
| Integer overflow | Signed integer overflow (undefined behaviour in C) | Speed * 10 overflows int16 at speed > 3276 |
| Array out of bounds | Access beyond array end or before start | gear_table[gear_pos] where gear_pos can be 0-5 but table has 5 entries |
| Null pointer dereference | Dereferencing pointer that is NULL or uninitialised | Calling function on result of malloc without null check |
| Division by zero | Divisor can be zero | rpm / gear_ratio where gear_ratio can be 0 in neutral |
| Invalid shift | Shift amount >= type width or negative | Bit shift by variable that can exceed 31 on 32-bit int |
| Data race | Concurrent access to shared variable without protection | ISR writes global; task reads global without critical section |
Polyspace Bug Finder: Runtime Error Detection
Polyspace Code Prover: Formal Proof
Code Prover Colour Scheme
GREEN -- Proven safe for ALL inputs
"This division can never produce zero divisor"
Strongest result: no test can disprove this
ORANGE -- Unproven (possible issue, not proven safe)
"Division by zero possible in some input combinations"
Requires manual review: is it a real bug or an
overly-conservative abstract interpretation?
RED -- Proven error (will always fail on this path)
"Division by zero is certain on this execution path"
Must be fixed before release
GREY -- Unreachable code
"This statement can never be executed"
Investigate: dead code or defensive code?Polyspace CLI Configuration
Bashpolyspace_analysis.sh
#!/bin/bash
# Polyspace Bug Finder analysis via CLI
set -e
COMPONENT="SpeedController"
RESULTS_DIR="polyspace_results/${COMPONENT}"
mkdir -p "${RESULTS_DIR}"
# Run Polyspace Bug Finder
polyspace-bug-finder \
-sources src/SpeedController.c src/FaultManager.c \
-I include/ include/autosar/ \
-D TARGET_AURIX TC387 \
-target aurix \
-misra3 required-rules \
-checkers all \
-results-dir "${RESULTS_DIR}" \
-report-template developer \
-format xml
# Parse results and check quality gate
python3 parse_polyspace.py "${RESULTS_DIR}/results.xml"
# For Code Prover (formal proof):
# polyspace-code-prover \
# -sources src/*.c -I include/ \
# -target aurix \
# -results-dir "${RESULTS_DIR}_proof"Summary
The green/orange/red colour scheme is the most important concept for interpreting Polyspace Code Prover results. A "green" result is a mathematical proof -- stronger than any test suite result. A "red" result is a proven bug -- it will cause a runtime error on the path where Polyspace found it, regardless of whether any test case exercises it. The "orange" result requires the most judgement: it means the abstract interpretation could not prove the code safe, but also could not prove it will fail. In practice, most oranges in well-written ASIL-B/C code are false positives from overly-conservative range estimates; the discipline is in reviewing each orange, adding range constraints for input variables where known, and documenting the rationale for any remaining oranges that are accepted.
🔬 Deep Dive — Core Concepts Expanded
This section builds on the foundational concepts covered above with additional technical depth, edge cases, and configuration nuances that separate competent engineers from experts. When working on production ECU projects, the details covered here are the ones most commonly responsible for integration delays and late-phase defects.
Key principles to reinforce:
- Configuration over coding: In AUTOSAR and automotive middleware environments, correctness is largely determined by ARXML configuration, not application code. A correctly implemented algorithm can produce wrong results due to a single misconfigured parameter.
- Traceability as a first-class concern: Every configuration decision should be traceable to a requirement, safety goal, or architecture decision. Undocumented configuration choices are a common source of regression defects when ECUs are updated.
- Cross-module dependencies: In tightly integrated automotive software stacks, changing one module's configuration often requires corresponding updates in dependent modules. Always perform a dependency impact analysis before submitting configuration changes.
🏭 How This Topic Appears in Production Projects
- Project integration phase: The concepts covered in this lesson are most commonly encountered during ECU integration testing — when multiple software components from different teams are combined for the first time. Issues that were invisible in unit tests frequently surface at this stage.
- Supplier/OEM interface: This is a topic that frequently appears in technical discussions between Tier-1 ECU suppliers and OEM system integrators. Engineers who can speak fluently about these details earn credibility and are often brought into critical design review meetings.
- Automotive tool ecosystem: Vector CANoe/CANalyzer, dSPACE tools, and ETAS INCA are the standard tools used to validate and measure the correct behaviour of the systems described in this lesson. Familiarity with these tools alongside the conceptual knowledge dramatically accelerates debugging in real projects.
⚠️ Common Mistakes and How to Avoid Them
- Assuming default configuration is correct: Automotive software tools ship with default configurations that are designed to compile and link, not to meet project-specific requirements. Every configuration parameter needs to be consciously set. 'It compiled' is not the same as 'it is correctly configured'.
- Skipping documentation of configuration rationale: In a 3-year ECU project with team turnover, undocumented configuration choices become tribal knowledge that disappears when engineers leave. Document why a parameter is set to a specific value, not just what it is set to.
- Testing only the happy path: Automotive ECUs must behave correctly under fault conditions, voltage variations, and communication errors. Always test the error handling paths as rigorously as the nominal operation. Many production escapes originate in untested error branches.
- Version mismatches between teams: In a multi-team project, the BSW team, SWC team, and system integration team may use different versions of the same ARXML file. Version management of all ARXML files in a shared repository is mandatory, not optional.
📊 Industry Note
Engineers who master both the theoretical concepts and the practical toolchain skills covered in this course are among the most sought-after professionals in the automotive software industry. The combination of AUTOSAR standards knowledge, safety engineering understanding, and hands-on configuration experience commands premium salaries at OEMs and Tier-1 suppliers globally.