A5-1-9: Improve performance, address duplication

[lcartey]

Description

Addresses three performance issues with A5-1-9:

• HC_ParamCons was incorrectly defined, referring to uses of the parameters when calculating the hash, instead of properties of the parameter (name and type). This causes exponential blow up in some databases (with lambdas with a lot of parameters and/or lots of uses).
• An optimiser issue where Variable.getName() was being magic-ked with an insufficiently restrictive set of variables, which ultimately led to the calculation of Function.getParameter(int i) creating a cross-product on indexes.
• HC_BlockStmt was calculating for a blocks, but hashStmtCons then filtered out any blocks not in lambdas. I've moved this restriction into HC_BlockStmt, which has helped enable us to run even on large databases (e.g. grpc/grpc). Ideally we would apply the lambda restriction to all elements in the LambdaEquivalence.qll, but this seems to be sufficient for now.

Also fixes #856, by excluding results that come from the same macro expansion.

Change request type

• Release or process automation (GitHub workflows, internal scripts)
• Internal documentation
• External documentation
• Query files (.ql, .qll, .qls or unit tests)
• External scripts (analysis report or other code shipped as part of a release)

Rules with added or modified queries

• No rules added
• Queries have been added for the following rules:
  • rule number here
• Queries have been modified for the following rules:
  • A5-1-9

Release change checklist

A change note (development_handbook.md#change-notes) is required for any pull request which modifies:

• The structure or layout of the release artifacts.
• The evaluation performance (memory, execution time) of an existing query.
• The results of an existing query in any circumstance.

If you are only adding new rule queries, a change note is not required.

Author: Is a change note required?

• Yes
• No

🚨🚨🚨
Reviewer: Confirm that format of shared queries (not the .qll file, the
.ql file that imports it) is valid by running them within VS Code.

• Confirmed

Reviewer: Confirm that either a change note is not required or the change note is required and has been added.

• Confirmed

Query development review checklist

For PRs that add new queries or modify existing queries, the following checklist should be completed by both the author and reviewer:

Author

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

Reviewer

• Have all the relevant rule package description files been checked in?
• Have you verified that the metadata properties of each new query is set appropriately?
• Do all the unit tests contain both "COMPLIANT" and "NON_COMPLIANT" cases?
• Are the alert messages properly formatted and consistent with the style guide?
• Have you run the queries on OpenPilot and verified that the performance and results are acceptable?
  As a rule of thumb, predicates specific to the query should take no more than 1 minute, and for simple queries be under 10 seconds. If this is not the case, this should be highlighted and agreed in the code review process.
• Does the query have an appropriate level of in-query comments/documentation?
• Have you considered/identified possible edge cases?
• Does the query not reinvent features in the standard library?
• Can the query be simplified further (not golfed!)

PR Overview

This pull request improves the performance of query A5-1-9 by addressing issues with parameter hashing, variable name resolution, and block statement processing that previously led to performance bottlenecks and false positives. Additionally, the change note documents these improvements and notes the exclusion of results from the same macro expansion.

Changes

File	Description
change_notes/2025-02-10-improve-perf-a5-1-9.md	Change note detailing performance improvements for IdenticalLambdaExpressions.ql and adjustments to reduce false positives

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