Summary:
This is now handled by a wrapper class SwapIndex, so MemIndex/DexIndex can be
immutable and focus on their job.
Old and busted:
I have a MemIndex, which holds a shared_ptr<vector<Symbol*>>, which keeps the
symbol slab alive. I update by calling build(shared_ptr<vector<Symbol*>>).
New hotness: I have a SwapIndex, which holds a unique_ptr<SymbolIndex>, which
holds a MemIndex, which holds a shared_ptr<void>, which keeps backing
data alive.
I update by building a new MemIndex and calling SwapIndex::reset().
Reviewers: kbobyrev, ioeric
Subscribers: ilya-biryukov, ioeric, MaskRay, jkorous, mgrang, arphaman, kadircet, cfe-commits
Differential Revision: https://reviews.llvm.org/D51422
llvm-svn: 341318
* Use consistent assertion messages in iterators implementations
* Silence a bunch of clang-tidy warnings: use `emplace_back` instead of
`push_back` where possible, make sure arguments have the same name in
header and implementation file, use for loop over ranges where possible
Reviewed by: ioeric
Differential Revision: https://reviews.llvm.org/D51528
llvm-svn: 341190
This patch introduces iterator cost concept to improve the performance
of Dex query iterators (mainly, AND iterator). Benchmarks show that the
queries become ~10% faster.
Before
```
-------------------------------------------------------
Benchmark Time CPU Iteration
-------------------------------------------------------
DexAdHocQueries 5883074 ns 5883018 ns 117
DexRealQ 959904457 ns 959898507 ns 1
```
After
```
-------------------------------------------------------
Benchmark Time CPU Iteration
-------------------------------------------------------
DexAdHocQueries 5238403 ns 5238361 ns 130
DexRealQ 873275207 ns 873269453 ns 1
```
Reviewed by: sammccall
Differential Revision: https://reviews.llvm.org/D51310
llvm-svn: 341057
Stop using `$$$` (empty) trigram and generating a posting list with all
items. Since TRUE iterator is already implemented and correctly inserted
when there are no real trigram posting lists, this is a valid
transformation.
Benchmarks show that this simple change allows ~30% speedup on dataset
of real completion queries.
Before
```
-------------------------------------------------------
Benchmark Time CPU Iterations
-------------------------------------------------------
DexAdHocQueries 5640321 ns 5640265 ns 120
DexRealQ 939835603 ns 939830296 ns 1
```
After
```
-------------------------------------------------------
Benchmark Time CPU Iterations
-------------------------------------------------------
DexAdHocQueries 3452014 ns 3451987 ns 203
DexRealQ 667455912 ns 667455750 ns 1
```
Reviewed by: ilya-biryukov
Differential Revision: https://reviews.llvm.org/D51287
llvm-svn: 340729
This patch introduces LIMIT iterator, which is very important for
improving the quality of search query. LIMIT iterators can be applied on
top of BOOST iterators to prevent populating query request with a huge
number of low-quality symbols.
Reviewed by: sammccall
Differential Revision: https://reviews.llvm.org/D51029
llvm-svn: 340605
This patch prints information about built index size estimation to
verbose logs. This is useful for optimizing memory usage of DexIndex and
comparisons with MemIndex.
Reviewed by: sammccall
Differential Revision: https://reviews.llvm.org/D51154
llvm-svn: 340601
This patch introduces BOOST iterator - a substantial block for efficient
and high-quality symbol retrieval. The concept of boosting allows
performing computationally inexpensive scoring on the query side so that
the final (expensive) scoring can only be applied on the items with the
highest preliminary score while eliminating the need to score too many
items.
Reviewed by: ilya-biryukov
Differential Revision: https://reviews.llvm.org/D50970
llvm-svn: 340409
This patch adds hidden Clangd flag ("use-dex-index") which replaces
(currently) default `MemIndex` with `DexIndex` for the static index.
Reviewed by: ioeric
Differential Revision: https://reviews.llvm.org/D50897
llvm-svn: 340262
This patch is a proof-of-concept Dex index implementation. It has
several flaws, which don't allow replacing static MemIndex yet, such as:
* Not being able to handle queries of small size (less than 3 symbols);
a way to solve this is generating trigrams of smaller size and having
such incomplete trigrams in the index structure.
* Speed measurements: while manually editing files in Vim and requesting
autocompletion gives an impression that the performance is at least
comparable with the current static index, having actual numbers is
important because we don't want to hurt the users and roll out slow
code. Eric (@ioeric) suggested that we should only replace MemIndex as
soon as we have the evidence that this is not a regression in terms of
performance. An approach which is likely to be successful here is to
wait until we have benchmark library in the LLVM core repository, which
is something I have suggested in the LLVM mailing lists, received
positive feedback on and started working on. I will add a dependency as
soon as the suggested patch is out for a review (currently there's at
least one complication which is being addressed by
https://github.com/google/benchmark/pull/649). Key performance
improvements for iterators are sorting by cost and the limit iterator.
* Quality measurements: currently, boosting iterator and two-phase
lookup stage are not implemented, without these the quality is likely to
be worse than the current implementation can yield. Measuring quality is
tricky, but another suggestion in the offline discussion was that the
drop-in replacement should only happen after Boosting iterators
implementation (and subsequent query enhancement).
The proposed changes do not affect Clangd functionality or performance,
`DexIndex` is only used in unit tests and not in production code.
Reviewed by: ioeric
Differential Revision: https://reviews.llvm.org/D50337
llvm-svn: 340175
Proposed changes:
* Cleanup comments in `clangd/index/dex/Iterator.h`: Vim's `gq`
formatting added redundant spaces instead of newlines in few
places
* Few comments in `OrIterator` are wrong
* Use `EXPECT_TRUE(Condition)` instead of
`EXPECT_THAT(Condition, true)` (same with `EXPECT_FALSE`)
* Don't expose `dump()` method to the public by misplacing
`private:`
This patch does not affect functionality.
Reviewed by: ioeric
Differential Revision: https://reviews.llvm.org/D50956
llvm-svn: 340157
This patch improves `dex::Iterator` string representation by
incorporating the information about the element which is currently being
pointed to by the `DocumentIterator`.
Reviewed by: ioeric
Differential Revision: https://reviews.llvm.org/D50689
llvm-svn: 339877
This patch handles trigram generation "short" identifiers and queries.
Trigram generator produces incomplete trigrams for short names so that
the same query iterator API can be used to match symbols which don't
have enough symbols to form a trigram and correctly handle queries which
also are not sufficient for generating a full trigram.
Reviewed by: ioeric
Differential revision: https://reviews.llvm.org/D50517
llvm-svn: 339548
This patch modifies `consume` function to allow retrieval of limited
number of symbols. This is the "cheap" implementation of top-level
limiting iterator. In the future we would like to have a complete limit
iterator implementation to insert it into the query subtrees, but in the
meantime this version would be enough for a fully-functional
proof-of-concept Dex implementation.
Reviewers: ioeric, ilya-biryukov
Reviewed by: ioeric
Differential Revision: https://reviews.llvm.org/D50500
llvm-svn: 339426
The original Dex Iterators patch (https://reviews.llvm.org/rL338017)
caused problems for Clang 3.6 and Clang 3.7 due to the compiler bug
which prevented inferring template parameter (`Size`) in create(And|Or)?
functions. It was reverted in https://reviews.llvm.org/rL338054.
In this revision the mentioned helper functions were replaced with
variadic templated versions.
Proposed changes were tested on multiple compiler versions, including
Clang 3.6 which originally caused the failure.
llvm-svn: 338116
This patch introduces three essential types of query iterators:
`DocumentIterator`, `AndIterator`, `OrIterator`. It provides a
convenient API for query tree generation and serves as a building block
for the next generation symbol index - Dex. Currently, many
optimizations are missed to improve code readability and to serve as the
reference implementation. Potential improvements are briefly mentioned
in `FIXME`s and will be addressed in the following patches.
Dex RFC in the mailing list:
http://lists.llvm.org/pipermail/clangd-dev/2018-July/000022.html
Iterators, their applications and potential extensions are explained in
detail in the design proposal:
https://docs.google.com/document/d/1C-A6PGT6TynyaX4PXyExNMiGmJ2jL1UwV91Kyx11gOI/edit#heading=h.903u1zon9nkj
Reviewers: ioeric, sammccall, ilya-biryukov
Subscribers: cfe-commits, klimek, jfb, mgrang, mgorny, MaskRay, jkorous,
arphaman
Differential Revision: https://reviews.llvm.org/D49546
llvm-svn: 338017
This patch introduces the core building block of the next-generation
Clangd symbol index - Dex. Search tokens are the keys in the inverted
index and represent a characteristic of a specific symbol: examples of
search token types (Token Namespaces) are
* Trigrams - these are essential for unqualified symbol name fuzzy
search * Scopes for filtering the symbols by the namespace * Paths, e.g.
these can be used to uprank symbols defined close to the edited file
This patch outlines the generic for such token namespaces, but only
implements trigram generation.
The intuition behind trigram generation algorithm is that each extracted
trigram is a valid sequence for Fuzzy Matcher jumps, proposed
implementation utilize existing FuzzyMatcher API for segmentation and
trigram extraction.
However, trigrams generation algorithm for the query string is different
from the previous one: it simply yields sequences of 3 consecutive
lowercased valid characters (letters, digits).
Dex RFC in the mailing list:
http://lists.llvm.org/pipermail/clangd-dev/2018-July/000022.html
The trigram generation techniques are described in detail in the
proposal:
https://docs.google.com/document/d/1C-A6PGT6TynyaX4PXyExNMiGmJ2jL1UwV91Kyx11gOI/edit#heading=h.903u1zon9nkj
Reviewers: sammccall, ioeric, ilya-biryukovA
Subscribers: cfe-commits, klimek, mgorny, MaskRay, jkorous, arphaman
Differential Revision: https://reviews.llvm.org/D49591
llvm-svn: 337901
Sam McCall