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Moved Symbol into its own header and implementation file
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Reviewers: ioeric

Subscribers: mgorny, jkorous, arphaman, kadircet, jdoerfert, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58774

llvm-svn: 355088
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gribozavr committed Feb 28, 2019
1 parent a073a18 commit 08b49b5
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Showing 14 changed files with 318 additions and 265 deletions.
1 change: 1 addition & 0 deletions clang-tools-extra/clangd/CMakeLists.txt
Expand Up @@ -63,6 +63,7 @@ add_clang_library(clangDaemon
index/MemIndex.cpp
index/Merge.cpp
index/Serialization.cpp
index/Symbol.cpp
index/SymbolCollector.cpp
index/SymbolID.cpp
index/SymbolLocation.cpp
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/CodeComplete.cpp
Expand Up @@ -34,6 +34,7 @@
#include "Trace.h"
#include "URI.h"
#include "index/Index.h"
#include "index/Symbol.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/Basic/LangOptions.h"
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/CodeComplete.h
Expand Up @@ -21,6 +21,7 @@
#include "Path.h"
#include "Protocol.h"
#include "index/Index.h"
#include "index/Symbol.h"
#include "index/SymbolOrigin.h"
#include "clang/Frontend/PrecompiledPreamble.h"
#include "clang/Sema/CodeCompleteConsumer.h"
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2 changes: 1 addition & 1 deletion clang-tools-extra/clangd/Headers.h
Expand Up @@ -12,7 +12,7 @@
#include "Path.h"
#include "Protocol.h"
#include "SourceCode.h"
#include "index/Index.h"
#include "index/Symbol.h"
#include "clang/Format/Format.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/PPCallbacks.h"
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/IncludeFixer.cpp
Expand Up @@ -13,6 +13,7 @@
#include "SourceCode.h"
#include "Trace.h"
#include "index/Index.h"
#include "index/Symbol.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/NestedNameSpecifier.h"
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/IncludeFixer.h
Expand Up @@ -12,6 +12,7 @@
#include "Diagnostics.h"
#include "Headers.h"
#include "index/Index.h"
#include "index/Symbol.h"
#include "clang/AST/Type.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/SourceLocation.h"
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/index/Background.cpp
Expand Up @@ -11,6 +11,7 @@
#include "Compiler.h"
#include "Logger.h"
#include "SourceCode.h"
#include "Symbol.h"
#include "Threading.h"
#include "Trace.h"
#include "URI.h"
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/index/FileIndex.h
Expand Up @@ -20,6 +20,7 @@
#include "MemIndex.h"
#include "Merge.h"
#include "index/CanonicalIncludes.h"
#include "index/Symbol.h"
#include "clang/Lex/Preprocessor.h"
#include <memory>

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61 changes: 0 additions & 61 deletions clang-tools-extra/clangd/index/Index.cpp
Expand Up @@ -16,67 +16,6 @@
namespace clang {
namespace clangd {

llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, Symbol::SymbolFlag F) {
if (F == Symbol::None)
return OS << "None";
std::string S;
if (F & Symbol::Deprecated)
S += "deprecated|";
if (F & Symbol::IndexedForCodeCompletion)
S += "completion|";
return OS << llvm::StringRef(S).rtrim('|');
}

llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Symbol &S) {
return OS << S.Scope << S.Name;
}

float quality(const Symbol &S) {
// This avoids a sharp gradient for tail symbols, and also neatly avoids the
// question of whether 0 references means a bad symbol or missing data.
if (S.References < 3)
return 1;
return std::log(S.References);
}

SymbolSlab::const_iterator SymbolSlab::find(const SymbolID &ID) const {
auto It = std::lower_bound(
Symbols.begin(), Symbols.end(), ID,
[](const Symbol &S, const SymbolID &I) { return S.ID < I; });
if (It != Symbols.end() && It->ID == ID)
return It;
return Symbols.end();
}

// Copy the underlying data of the symbol into the owned arena.
static void own(Symbol &S, llvm::UniqueStringSaver &Strings) {
visitStrings(S, [&](llvm::StringRef &V) { V = Strings.save(V); });
}

void SymbolSlab::Builder::insert(const Symbol &S) {
auto R = SymbolIndex.try_emplace(S.ID, Symbols.size());
if (R.second) {
Symbols.push_back(S);
own(Symbols.back(), UniqueStrings);
} else {
auto &Copy = Symbols[R.first->second] = S;
own(Copy, UniqueStrings);
}
}

SymbolSlab SymbolSlab::Builder::build() && {
Symbols = {Symbols.begin(), Symbols.end()}; // Force shrink-to-fit.
// Sort symbols so the slab can binary search over them.
llvm::sort(Symbols,
[](const Symbol &L, const Symbol &R) { return L.ID < R.ID; });
// We may have unused strings from overwritten symbols. Build a new arena.
llvm::BumpPtrAllocator NewArena;
llvm::UniqueStringSaver Strings(NewArena);
for (auto &S : Symbols)
own(S, Strings);
return SymbolSlab(std::move(NewArena), std::move(Symbols));
}

llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, RefKind K) {
if (K == RefKind::Unknown)
return OS << "Unknown";
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204 changes: 1 addition & 203 deletions clang-tools-extra/clangd/index/Index.h
Expand Up @@ -10,9 +10,9 @@
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_INDEX_H

#include "ExpectedTypes.h"
#include "Symbol.h"
#include "SymbolID.h"
#include "SymbolLocation.h"
#include "SymbolOrigin.h"
#include "clang/Index/IndexSymbol.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/DenseMap.h"
Expand All @@ -22,7 +22,6 @@
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/JSON.h"
#include "llvm/Support/StringSaver.h"
#include <array>
#include <limits>
#include <mutex>
Expand All @@ -32,207 +31,6 @@
namespace clang {
namespace clangd {

// The class presents a C++ symbol, e.g. class, function.
//
// WARNING: Symbols do not own much of their underlying data - typically strings
// are owned by a SymbolSlab. They should be treated as non-owning references.
// Copies are shallow.
// When adding new unowned data fields to Symbol, remember to update:
// - SymbolSlab::Builder in Index.cpp, to copy them to the slab's storage.
// - mergeSymbol in Merge.cpp, to properly combine two Symbols.
//
// A fully documented symbol can be split as:
// size_type std::map<k, t>::count(const K& key) const
// | Return | Scope |Name| Signature |
// We split up these components to allow display flexibility later.
struct Symbol {
// The ID of the symbol.
SymbolID ID;
// The symbol information, like symbol kind.
index::SymbolInfo SymInfo;
// The unqualified name of the symbol, e.g. "bar" (for ns::bar).
llvm::StringRef Name;
// The containing namespace. e.g. "" (global), "ns::" (top-level namespace).
llvm::StringRef Scope;
// The location of the symbol's definition, if one was found.
// This just covers the symbol name (e.g. without class/function body).
SymbolLocation Definition;
// The location of the preferred declaration of the symbol.
// This just covers the symbol name.
// This may be the same as Definition.
//
// A C++ symbol may have multiple declarations, and we pick one to prefer.
// * For classes, the canonical declaration should be the definition.
// * For non-inline functions, the canonical declaration typically appears
// in the ".h" file corresponding to the definition.
SymbolLocation CanonicalDeclaration;
// The number of translation units that reference this symbol from their main
// file. This number is only meaningful if aggregated in an index.
unsigned References = 0;
/// Where this symbol came from. Usually an index provides a constant value.
SymbolOrigin Origin = SymbolOrigin::Unknown;
/// A brief description of the symbol that can be appended in the completion
/// candidate list. For example, "(X x, Y y) const" is a function signature.
/// Only set when the symbol is indexed for completion.
llvm::StringRef Signature;
/// What to insert when completing this symbol, after the symbol name.
/// This is in LSP snippet syntax (e.g. "({$0})" for a no-args function).
/// (When snippets are disabled, the symbol name alone is used).
/// Only set when the symbol is indexed for completion.
llvm::StringRef CompletionSnippetSuffix;
/// Documentation including comment for the symbol declaration.
llvm::StringRef Documentation;
/// Type when this symbol is used in an expression. (Short display form).
/// e.g. return type of a function, or type of a variable.
/// Only set when the symbol is indexed for completion.
llvm::StringRef ReturnType;

/// Raw representation of the OpaqueType of the symbol, used for scoring
/// purposes.
/// Only set when the symbol is indexed for completion.
llvm::StringRef Type;

struct IncludeHeaderWithReferences {
IncludeHeaderWithReferences() = default;

IncludeHeaderWithReferences(llvm::StringRef IncludeHeader,
unsigned References)
: IncludeHeader(IncludeHeader), References(References) {}

/// This can be either a URI of the header to be #include'd
/// for this symbol, or a literal header quoted with <> or "" that is
/// suitable to be included directly. When it is a URI, the exact #include
/// path needs to be calculated according to the URI scheme.
///
/// Note that the include header is a canonical include for the symbol and
/// can be different from FileURI in the CanonicalDeclaration.
llvm::StringRef IncludeHeader = "";
/// The number of translation units that reference this symbol and include
/// this header. This number is only meaningful if aggregated in an index.
unsigned References = 0;
};
/// One Symbol can potentially be incuded via different headers.
/// - If we haven't seen a definition, this covers all declarations.
/// - If we have seen a definition, this covers declarations visible from
/// any definition.
/// Only set when the symbol is indexed for completion.
llvm::SmallVector<IncludeHeaderWithReferences, 1> IncludeHeaders;

enum SymbolFlag : uint8_t {
None = 0,
/// Whether or not this symbol is meant to be used for the code completion.
/// See also isIndexedForCodeCompletion().
/// Note that we don't store completion information (signature, snippet,
/// type, inclues) if the symbol is not indexed for code completion.
IndexedForCodeCompletion = 1 << 0,
/// Indicates if the symbol is deprecated.
Deprecated = 1 << 1,
// Symbol is an implementation detail.
ImplementationDetail = 1 << 2,
// Symbol is visible to other files (not e.g. a static helper function).
VisibleOutsideFile = 1 << 3,
};

SymbolFlag Flags = SymbolFlag::None;
/// FIXME: also add deprecation message and fixit?
};
inline Symbol::SymbolFlag operator|(Symbol::SymbolFlag A, Symbol::SymbolFlag B) {
return static_cast<Symbol::SymbolFlag>(static_cast<uint8_t>(A) |
static_cast<uint8_t>(B));
}
inline Symbol::SymbolFlag &operator|=(Symbol::SymbolFlag &A, Symbol::SymbolFlag B) {
return A = A | B;
}
llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Symbol &S);
raw_ostream &operator<<(raw_ostream &, Symbol::SymbolFlag);

// Invokes Callback with each StringRef& contained in the Symbol.
// Useful for deduplicating backing strings.
template <typename Callback> void visitStrings(Symbol &S, const Callback &CB) {
CB(S.Name);
CB(S.Scope);
CB(S.Signature);
CB(S.CompletionSnippetSuffix);
CB(S.Documentation);
CB(S.ReturnType);
CB(S.Type);
auto RawCharPointerCB = [&CB](const char *&P) {
llvm::StringRef S(P);
CB(S);
assert(!S.data()[S.size()] && "Visited StringRef must be null-terminated");
P = S.data();
};
RawCharPointerCB(S.CanonicalDeclaration.FileURI);
RawCharPointerCB(S.Definition.FileURI);

for (auto &Include : S.IncludeHeaders)
CB(Include.IncludeHeader);
}

// Computes query-independent quality score for a Symbol.
// This currently falls in the range [1, ln(#indexed documents)].
// FIXME: this should probably be split into symbol -> signals
// and signals -> score, so it can be reused for Sema completions.
float quality(const Symbol &S);

// An immutable symbol container that stores a set of symbols.
// The container will maintain the lifetime of the symbols.
class SymbolSlab {
public:
using const_iterator = std::vector<Symbol>::const_iterator;
using iterator = const_iterator;
using value_type = Symbol;

SymbolSlab() = default;

const_iterator begin() const { return Symbols.begin(); }
const_iterator end() const { return Symbols.end(); }
const_iterator find(const SymbolID &SymID) const;

size_t size() const { return Symbols.size(); }
bool empty() const { return Symbols.empty(); }
// Estimates the total memory usage.
size_t bytes() const {
return sizeof(*this) + Arena.getTotalMemory() +
Symbols.capacity() * sizeof(Symbol);
}

// SymbolSlab::Builder is a mutable container that can 'freeze' to SymbolSlab.
// The frozen SymbolSlab will use less memory.
class Builder {
public:
Builder() : UniqueStrings(Arena) {}

// Adds a symbol, overwriting any existing one with the same ID.
// This is a deep copy: underlying strings will be owned by the slab.
void insert(const Symbol &S);

// Returns the symbol with an ID, if it exists. Valid until next insert().
const Symbol *find(const SymbolID &ID) {
auto I = SymbolIndex.find(ID);
return I == SymbolIndex.end() ? nullptr : &Symbols[I->second];
}

// Consumes the builder to finalize the slab.
SymbolSlab build() &&;

private:
llvm::BumpPtrAllocator Arena;
// Intern table for strings. Contents are on the arena.
llvm::UniqueStringSaver UniqueStrings;
std::vector<Symbol> Symbols;
// Values are indices into Symbols vector.
llvm::DenseMap<SymbolID, size_t> SymbolIndex;
};

private:
SymbolSlab(llvm::BumpPtrAllocator Arena, std::vector<Symbol> Symbols)
: Arena(std::move(Arena)), Symbols(std::move(Symbols)) {}

llvm::BumpPtrAllocator Arena; // Owns Symbol data that the Symbols do not.
std::vector<Symbol> Symbols; // Sorted by SymbolID to allow lookup.
};

// Describes the kind of a cross-reference.
//
// This is a bitfield which can be combined from different kinds.
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/index/Merge.cpp
Expand Up @@ -9,6 +9,7 @@
#include "Merge.h"
#include "Logger.h"
#include "Trace.h"
#include "index/Symbol.h"
#include "index/SymbolLocation.h"
#include "index/SymbolOrigin.h"
#include "llvm/ADT/STLExtras.h"
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1 change: 1 addition & 0 deletions clang-tools-extra/clangd/index/Serialization.h
Expand Up @@ -26,6 +26,7 @@

#include "Headers.h"
#include "Index.h"
#include "index/Symbol.h"
#include "llvm/Support/Error.h"

namespace clang {
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