This `select` clause had become very slow after we started caching
`ElementBase::toString` because the query used string concatenation to
produce alert messages, and those string concatenations were done very
early in the pipeline, producing lots of strings that would be discarded
moments later.
By using `$@` to interpolate elements into strings, the concatenation is
done outside of QL.
Testing on a Chromium snapshot, this commit takes us from
#select#ff ................ 6m2s
to
#select#cpe#134#fff ....... 15.2s
We don't hyphenate "QL-library" and there were a few typos. Feel free to further revise this if I've changed the meaning too much.
As discussed separately, I was unable to raise this as a PR in GitHub.com and had to resort to a direct commit.
(cherry picked from commit e29468135d)
This predicate is effectively a Cartesian product between all enum
types. It's infeasible to compute it in full, so luckily the optimizer
has been able to apply enough magic to make it feasible. That's not a
robust solution, and it has indeed broken on at least one version of the
1.24 release candidate.
On a Chromium snapshot where I ran the LGTM suite overnight, the
`m#MistypedFunctionArguments::arithTypesMatch#bb` predicate (magic for
`arithTypesMatch`) took 170m5s. That was commit b69fdf5 from the
internal repo. I tried to reproduce it in VSCode, this time with commit
646646, but it wasn't quite as bad: the predicate took only 38 seconds.
In any case, making the problematic predicate `pragma[inline]` removes
the slow magic and makes the `MistypedFunctionArguments.ql` query
faster.
- Merged the two notes for `cpp/uncontrolled-allocation-size` into one.
- Added note about renaming of a query id.
- Moved the use of IR in queries from the library section to the queries
section, rephrasing the note in terms of query results/performance
rather than library implementation.
- Grouped, without text changes, the three notes about the `Allocation`
library
- Grouped all the notes about standard-library models, abbreviating them
to eliminate the common text.
- Removed the note about `strlen` (#2647) since that should no longer
affect the results of queries or IR data flow after we started using
unsound IR for data flow.
