swiftlang/swift

[SR-927] Integrate leaks infrastructure into stdlib unittests

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#43,539 opened on Mar 12, 2016

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good first issueimprovementstandard library

Description
Previous ID SR-927
Radar None
Original Reporter @gottesmm
Type Improvement
Votes 0
Component/s Standard Library
Labels Improvement, StarterBug
Assignee None
Priority Medium

md5: af9683a46d2c1fd2060e2a6887b581f4

Issue Description:

Currently we have special infrastructure for precise leaks checking that we use to check for leaks in our benchmarks.

The way this works is that when the pass -DSWIFT_RUNTIME_ENABLE_LEAK_CHECKER is set to yes, the runtime provides the two entry points:

swift_leaks_startTrackingObjects(const char *name)
swift_leaks_stopTrackingObjects(const char *name)

where name is a string with the name of the test being run. When startTrackingObjects is called, a global set is initialized. This is our "live object set". From that point forward, whenever we allocate a swift or objective-c object, we add it to the set. When ever we deallocate such an object, we remove the object from that set.

When stopTrackingObjects is called, the runtime emits via simple json the current state of the live object set.

The nice thing about this approach is that it enables fine-grained leaks testing of specific tests.

As mentioned at the top of the description, currently the leak checker has been integrated only into the benchmarks. This bug is to track the work of making changes to stdlib unit tests to enable the leaks checker to work on the stdlib unit tests.

This is a non-trivial amount of work, but would be a good starter bug that would improve the quality of the compiler.

Contributor guide

Tech stack
swift
Domain
testingperformance
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Familiarity with Swift runtime and unit testing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate how the leaks checker is currently integrated into benchmarks (likely via Swift benchmarks directory) and understand the use of swift leaks startTrackingObjects and swift leaks stopTrackingObjects. Then, adapt the stdlib unit test runner to initialize the leak checker before each test and report leaks after. Look for relevant files in the stdlib test directory and the runtime leak checker code. Consider any existing macros or test infrastructure that could be reused.