hokein created this revision.
hokein added a reviewer: sammccall.
Herald added subscribers: kadircet, arphaman, jkorous, MaskRay, ioeric,
ilya-biryukov.
This would buy us more memory. Using a 32-bits integer is enough for
most human-readable source code (up to 4M lines and 4K columns).
Previsouly, we used 8 bytes for a position, now 4 bytes, it would save
us 8 bytes for each Ref and each Symbol instance.
For LLVM-project binary index file, we save ~13% memory.
| Before | After |
| 412MB | 355MB |
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D53363
Files:
clangd/index/Index.h
clangd/index/YAMLSerialization.cpp
unittests/clangd/FileIndexTests.cpp
unittests/clangd/SerializationTests.cpp
Index: unittests/clangd/SerializationTests.cpp
===================================================================
--- unittests/clangd/SerializationTests.cpp
+++ unittests/clangd/SerializationTests.cpp
@@ -33,12 +33,8 @@
Lang: Cpp
CanonicalDeclaration:
FileURI: file:///path/foo.h
- Start:
- Line: 1
- Column: 0
- End:
- Line: 1
- Column: 1
+ Start: 4096 # Line 1, Column 0
+ End: 4097 # Line 1, Column 1
Origin: 4
Flags: 1
Documentation: 'Foo doc'
@@ -59,12 +55,8 @@
Lang: Cpp
CanonicalDeclaration:
FileURI: file:///path/bar.h
- Start:
- Line: 1
- Column: 0
- End:
- Line: 1
- Column: 1
+ Start: 4096 # Line 1, Column 0
+ End: 4097 # Line 1, Column 1
Flags: 2
Signature: '-sig'
CompletionSnippetSuffix: '-snippet'
@@ -75,12 +67,8 @@
- Kind: 4
Location:
FileURI: file:///path/foo.cc
- Start:
- Line: 5
- Column: 3
- End:
- Line: 5
- Column: 8
+ Start: 20483 # Line 5, Column 3
+ End: 20485 # Line5, Column 8
)";
MATCHER_P(ID, I, "") { return arg.ID == cantFail(SymbolID::fromStr(I)); }
Index: unittests/clangd/FileIndexTests.cpp
===================================================================
--- unittests/clangd/FileIndexTests.cpp
+++ unittests/clangd/FileIndexTests.cpp
@@ -32,10 +32,10 @@
using testing::UnorderedElementsAre;
MATCHER_P(RefRange, Range, "") {
- return std::tie(arg.Location.Start.Line, arg.Location.Start.Column,
- arg.Location.End.Line, arg.Location.End.Column) ==
- std::tie(Range.start.line, Range.start.character, Range.end.line,
- Range.end.character);
+ return arg.Location.Start.Line == Range.start.line &&
+ arg.Location.Start.Column == Range.start.character &&
+ arg.Location.End.Line == Range.end.line &&
+ arg.Location.End.Column == Range.end.character;
}
MATCHER_P(FileURI, F, "") { return arg.Location.FileURI == F; }
MATCHER_P(DeclURI, U, "") { return arg.CanonicalDeclaration.FileURI == U; }
Index: clangd/index/YAMLSerialization.cpp
===================================================================
--- clangd/index/YAMLSerialization.cpp
+++ clangd/index/YAMLSerialization.cpp
@@ -94,18 +94,37 @@
uint8_t Origin = 0;
};
-template <> struct MappingTraits<SymbolLocation::Position> {
- static void mapping(IO &IO, SymbolLocation::Position &Value) {
- IO.mapRequired("Line", Value.Line);
- IO.mapRequired("Column", Value.Column);
+struct NormalizedPosition {
+ using Position = clang::clangd::SymbolLocation::Position;
+ NormalizedPosition(IO &) {}
+ NormalizedPosition(IO &, const Position &Pos) {
+ static_assert(
+ sizeof(Position) == sizeof(uint32_t),
+ "SymbolLocation::Position structure can not fit into a uint32_t.");
+ value = (Pos.Line << Position::ColumnBits) + Pos.Column;
}
+
+ Position denormalize(IO &) {
+ Position Pos;
+ Pos.Line = value >> Position::ColumnBits;
+ Pos.Column = value & ((1 << Position::ColumnBits) - 1);
+ return Pos;
+ }
+
+ // Encode the SymbolLocation::Position:
+ // | Line | Column |
+ uint32_t value;
};
template <> struct MappingTraits<SymbolLocation> {
static void mapping(IO &IO, SymbolLocation &Value) {
IO.mapRequired("FileURI", Value.FileURI);
- IO.mapRequired("Start", Value.Start);
- IO.mapRequired("End", Value.End);
+ MappingNormalization<NormalizedPosition, SymbolLocation::Position> NStart(
+ IO, Value.Start);
+ IO.mapRequired("Start", NStart->value);
+ MappingNormalization<NormalizedPosition, SymbolLocation::Position> NEnd(
+ IO, Value.End);
+ IO.mapRequired("End", NEnd->value);
}
};
Index: clangd/index/Index.h
===================================================================
--- clangd/index/Index.h
+++ clangd/index/Index.h
@@ -33,10 +33,17 @@
struct SymbolLocation {
// Specify a position (Line, Column) of symbol. Using Line/Column allows us to
// build LSP responses without reading the file content.
+ //
+ // Position is encoded as a 32-bits integer like below:
+ // |<--- 20 bits --->|<-12 bits->|
+ // |<--- Line --->|<- Column->|
struct Position {
- uint32_t Line = 0; // 0-based
+ static constexpr int LineBits = 20;
+ static constexpr int ColumnBits = 12;
+
+ uint32_t Line : LineBits; // 0-based
// Using UTF-16 code units.
- uint32_t Column = 0; // 0-based
+ uint32_t Column : ColumnBits; // 0-based
};
// The URI of the source file where a symbol occurs.
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