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 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 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
Kirill Bobyrev