- Previously, only callable package name sets were implemented, because
the compiler cannot economically compute classifier package sets for
libraries. This has not changed. However, the K2 IntelliJ plugin and
standalone Analysis API can very easily compute classifier package
sets. Hence, this commit adds support to `FirSymbolNamesProvider` for
such sets.
- Similar to callable package sets, classifier package sets (1) improve
the memory usage of symbol names providers and (2) improve the
performance of `mayHaveTopLevelClassifier`, which is a significant
bottleneck in the IDE.
- In many cases, the package sets for callables and classifiers are the
same. For example, the IDE Kotlin declaration provider computes the
set of packages that contain any classifier and/or callable, for the
following reasons: (1) indexing package names without filtering for
declarations is much faster, (2) computing separate sets is not free
both in time and memory, and (3) the performance impact of having a
more narrow set for callables is expected to be negligible. For this
reason, `FirSymbolNamesProvider.getPackageNames` exists to provide a
shared package set.
- The `hasSpecific*PackageNamesComputation` properties are required to
avoid caching the same package set in cached symbol names providers
twice. Because these properties are constant, they can be checked very
quickly, and no time has to be wasted trying a specific package set
computation to find out whether it's supported.
### IDE Performance Results
Package set construction performance improved in the IDE in multiple
benchmarks. This improves the performance of symbol providers overall,
which has a direct impact on completion, code analysis, and Find Usages.
In a local manual run of the `intellij_commit/setUp` Find Usages
performance test, the total time spent in `getClassLikeSymbolByClassId`
improved from ~18.7s to ~11.2s. Due to parallel resolve, this does not
translate to a wall clock improvement of 7 seconds, but rather of a few
seconds.
Some performance tests improved markedly in warmup, with for example
`toolbox_enterprise/genUuid` Find Usages having an improvement in
`StubBasedFirDeserializedSymbolProvider.getClassLikeSymbolByClassId`
from 2.4s to 0.2s. This has a direct impact on the first-run performance
of the tested Find Usages command.
So far, classifier package sets in the IDE are only implemented for
libraries, and library sessions are cached after the first warmup.
Because the biggest impact of classifier package sets is avoiding
computation of "class names in package" sets, the impact of this
optimization is not accurately reflected in the timings reported by our
performance tests. `toolbox_enterprise/genUuid` above is a good example,
as the warmup timings are great, but after warmup,
`StubBasedFirDeserializedSymbolProvider.getClassLikeSymbolByClassId`
improved only from 150ms to 70ms.
`toolbox_enterprise/genUuid` is another example, as we can confidently
say that the first-run Find Usages performance has improved (which makes
a difference for the user), but it is unclear by how much, as warmup is
not measured in performance tests.
The same optimization for source sessions will be easier to measure, as
source sessions are invalidated after each performance test run. This
commit lays the groundwork for that as well, because source session
support only requires the requisite package set computation in the
IDE declaration provider to be implemented.
^KT-62553 fixed
Marco Pennekamp
6474ff88fa