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llvm-project/clang-tools-extra/clangd/FindSymbols.cpp

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//===--- FindSymbols.cpp ------------------------------------*- C++-*------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "FindSymbols.h"
#include "AST.h"
#include "FuzzyMatch.h"
#include "ParsedAST.h"
#include "Quality.h"
#include "SourceCode.h"
#include "index/Index.h"
#include "support/Logger.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/Index/IndexDataConsumer.h"
#include "clang/Index/IndexSymbol.h"
#include "clang/Index/IndexingAction.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ScopedPrinter.h"
#include <limits>
#include <tuple>
#define DEBUG_TYPE "FindSymbols"
namespace clang {
namespace clangd {
namespace {
using ScoredSymbolInfo = std::pair<float, SymbolInformation>;
struct ScoredSymbolGreater {
bool operator()(const ScoredSymbolInfo &L, const ScoredSymbolInfo &R) {
if (L.first != R.first)
return L.first > R.first;
return L.second.name < R.second.name; // Earlier name is better.
}
};
// Returns true if \p Query can be found as a sub-sequence inside \p Scope.
bool approximateScopeMatch(llvm::StringRef Scope, llvm::StringRef Query) {
assert(Scope.empty() || Scope.endswith("::"));
assert(Query.empty() || Query.endswith("::"));
while (!Scope.empty() && !Query.empty()) {
auto Colons = Scope.find("::");
assert(Colons != llvm::StringRef::npos);
llvm::StringRef LeadingSpecifier = Scope.slice(0, Colons + 2);
Scope = Scope.slice(Colons + 2, llvm::StringRef::npos);
Query.consume_front(LeadingSpecifier);
}
return Query.empty();
}
} // namespace
llvm::Expected<Location> indexToLSPLocation(const SymbolLocation &Loc,
llvm::StringRef TUPath) {
auto Path = URI::resolve(Loc.FileURI, TUPath);
if (!Path)
return error("Could not resolve path for file '{0}': {1}", Loc.FileURI,
Path.takeError());
Location L;
L.uri = URIForFile::canonicalize(*Path, TUPath);
Position Start, End;
Start.line = Loc.Start.line();
Start.character = Loc.Start.column();
End.line = Loc.End.line();
End.character = Loc.End.column();
L.range = {Start, End};
return L;
}
llvm::Expected<Location> symbolToLocation(const Symbol &Sym,
llvm::StringRef TUPath) {
// Prefer the definition over e.g. a function declaration in a header
return indexToLSPLocation(
Sym.Definition ? Sym.Definition : Sym.CanonicalDeclaration, TUPath);
}
llvm::Expected<std::vector<SymbolInformation>>
getWorkspaceSymbols(llvm::StringRef Query, int Limit,
const SymbolIndex *const Index, llvm::StringRef HintPath) {
std::vector<SymbolInformation> Result;
if (!Index)
return Result;
// Lookup for qualified names are performed as:
// - Exact namespaces are boosted by the index.
// - Approximate matches are (sub-scope match) included via AnyScope logic.
// - Non-matching namespaces (no sub-scope match) are post-filtered.
auto Names = splitQualifiedName(Query);
FuzzyFindRequest Req;
Req.Query = std::string(Names.second);
// FuzzyFind doesn't want leading :: qualifier.
auto HasLeadingColons = Names.first.consume_front("::");
// Limit the query to specific namespace if it is fully-qualified.
Req.AnyScope = !HasLeadingColons;
// Boost symbols from desired namespace.
if (HasLeadingColons || !Names.first.empty())
Req.Scopes = {std::string(Names.first)};
if (Limit) {
Req.Limit = Limit;
// If we are boosting a specific scope allow more results to be retrieved,
// since some symbols from preferred namespaces might not make the cut.
if (Req.AnyScope && !Req.Scopes.empty())
*Req.Limit *= 5;
}
TopN<ScoredSymbolInfo, ScoredSymbolGreater> Top(
Req.Limit ? *Req.Limit : std::numeric_limits<size_t>::max());
FuzzyMatcher Filter(Req.Query);
Index->fuzzyFind(Req, [HintPath, &Top, &Filter, AnyScope = Req.AnyScope,
ReqScope = Names.first](const Symbol &Sym) {
llvm::StringRef Scope = Sym.Scope;
// Fuzzyfind might return symbols from irrelevant namespaces if query was
// not fully-qualified, drop those.
if (AnyScope && !approximateScopeMatch(Scope, ReqScope))
return;
auto Loc = symbolToLocation(Sym, HintPath);
if (!Loc) {
log("Workspace symbols: {0}", Loc.takeError());
return;
}
SymbolQualitySignals Quality;
Quality.merge(Sym);
SymbolRelevanceSignals Relevance;
Relevance.Name = Sym.Name;
Relevance.Query = SymbolRelevanceSignals::Generic;
// If symbol and request scopes do not match exactly, apply a penalty.
Relevance.InBaseClass = AnyScope && Scope != ReqScope;
if (auto NameMatch = Filter.match(Sym.Name))
Relevance.NameMatch = *NameMatch;
else {
log("Workspace symbol: {0} didn't match query {1}", Sym.Name,
Filter.pattern());
return;
}
Relevance.merge(Sym);
auto QualScore = Quality.evaluateHeuristics();
auto RelScore = Relevance.evaluateHeuristics();
auto Score = evaluateSymbolAndRelevance(QualScore, RelScore);
dlog("FindSymbols: {0}{1} = {2}\n{3}{4}\n", Sym.Scope, Sym.Name, Score,
Quality, Relevance);
SymbolInformation Info;
Info.name = (Sym.Name + Sym.TemplateSpecializationArgs).str();
Info.kind = indexSymbolKindToSymbolKind(Sym.SymInfo.Kind);
Info.location = *Loc;
Scope.consume_back("::");
Info.containerName = Scope.str();
// Exposed score excludes fuzzy-match component, for client-side re-ranking.
Info.score = Relevance.NameMatch > std::numeric_limits<float>::epsilon()
? Score / Relevance.NameMatch
: QualScore;
Top.push({Score, std::move(Info)});
});
for (auto &R : std::move(Top).items())
Result.push_back(std::move(R.second));
return Result;
}
namespace {
std::string getSymbolName(ASTContext &Ctx, const NamedDecl &ND) {
// Print `MyClass(Category)` instead of `Category` and `MyClass()` instead
// of `anonymous`.
if (const auto *Container = dyn_cast<ObjCContainerDecl>(&ND))
return printObjCContainer(*Container);
// Differentiate between class and instance methods: print `-foo` instead of
// `foo` and `+sharedInstance` instead of `sharedInstance`.
if (const auto *Method = dyn_cast<ObjCMethodDecl>(&ND)) {
std::string Name;
llvm::raw_string_ostream OS(Name);
OS << (Method->isInstanceMethod() ? '-' : '+');
Method->getSelector().print(OS);
OS.flush();
return Name;
}
return printName(Ctx, ND);
}
std::string getSymbolDetail(ASTContext &Ctx, const NamedDecl &ND) {
PrintingPolicy P(Ctx.getPrintingPolicy());
P.SuppressScope = true;
P.SuppressUnwrittenScope = true;
P.AnonymousTagLocations = false;
P.PolishForDeclaration = true;
std::string Detail;
llvm::raw_string_ostream OS(Detail);
if (ND.getDescribedTemplateParams()) {
OS << "template ";
}
if (const auto *VD = dyn_cast<ValueDecl>(&ND)) {
// FIXME: better printing for dependent type
if (isa<CXXConstructorDecl>(VD)) {
std::string ConstructorType = VD->getType().getAsString(P);
// Print constructor type as "(int)" instead of "void (int)".
llvm::StringRef WithoutVoid = ConstructorType;
WithoutVoid.consume_front("void ");
OS << WithoutVoid;
} else if (!isa<CXXDestructorDecl>(VD)) {
VD->getType().print(OS, P);
}
} else if (const auto *TD = dyn_cast<TagDecl>(&ND)) {
OS << TD->getKindName();
} else if (isa<TypedefNameDecl>(&ND)) {
OS << "type alias";
} else if (isa<ConceptDecl>(&ND)) {
OS << "concept";
}
return std::move(OS.str());
}
llvm::Optional<DocumentSymbol> declToSym(ASTContext &Ctx, const NamedDecl &ND) {
auto &SM = Ctx.getSourceManager();
SourceLocation BeginLoc = SM.getSpellingLoc(SM.getFileLoc(ND.getBeginLoc()));
SourceLocation EndLoc = SM.getSpellingLoc(SM.getFileLoc(ND.getEndLoc()));
const auto SymbolRange =
toHalfOpenFileRange(SM, Ctx.getLangOpts(), {BeginLoc, EndLoc});
if (!SymbolRange)
return llvm::None;
index::SymbolInfo SymInfo = index::getSymbolInfo(&ND);
// FIXME: This is not classifying constructors, destructors and operators
// correctly.
SymbolKind SK = indexSymbolKindToSymbolKind(SymInfo.Kind);
DocumentSymbol SI;
SI.name = getSymbolName(Ctx, ND);
SI.kind = SK;
SI.deprecated = ND.isDeprecated();
SI.range = Range{sourceLocToPosition(SM, SymbolRange->getBegin()),
sourceLocToPosition(SM, SymbolRange->getEnd())};
SI.detail = getSymbolDetail(Ctx, ND);
SourceLocation NameLoc = ND.getLocation();
SourceLocation FallbackNameLoc;
if (NameLoc.isMacroID()) {
if (isSpelledInSource(NameLoc, SM)) {
// Prefer the spelling loc, but save the expansion loc as a fallback.
FallbackNameLoc = SM.getExpansionLoc(NameLoc);
NameLoc = SM.getSpellingLoc(NameLoc);
} else {
NameLoc = SM.getExpansionLoc(NameLoc);
}
}
auto ComputeSelectionRange = [&](SourceLocation L) -> Range {
Position NameBegin = sourceLocToPosition(SM, L);
Position NameEnd = sourceLocToPosition(
SM, Lexer::getLocForEndOfToken(L, 0, SM, Ctx.getLangOpts()));
return Range{NameBegin, NameEnd};
};
SI.selectionRange = ComputeSelectionRange(NameLoc);
if (!SI.range.contains(SI.selectionRange) && FallbackNameLoc.isValid()) {
// 'selectionRange' must be contained in 'range'. In cases where clang
// reports unrelated ranges, we first try falling back to the expansion
// loc for the selection range.
SI.selectionRange = ComputeSelectionRange(FallbackNameLoc);
}
if (!SI.range.contains(SI.selectionRange)) {
// If the containment relationship still doesn't hold, throw away
// 'range' and use 'selectionRange' for both.
SI.range = SI.selectionRange;
}
return SI;
}
/// A helper class to build an outline for the parse AST. It traverses the AST
/// directly instead of using RecursiveASTVisitor (RAV) for three main reasons:
/// - there is no way to keep RAV from traversing subtrees we are not
/// interested in. E.g. not traversing function locals or implicit template
/// instantiations.
/// - it's easier to combine results of recursive passes,
/// - visiting decls is actually simple, so we don't hit the complicated
/// cases that RAV mostly helps with (types, expressions, etc.)
class DocumentOutline {
// A DocumentSymbol we're constructing.
// We use this instead of DocumentSymbol directly so that we can keep track
// of the nodes we insert for macros.
class SymBuilder {
std::vector<SymBuilder> Children;
DocumentSymbol Symbol; // Symbol.children is empty, use Children instead.
// Macro expansions that this node or its parents are associated with.
// (Thus we will never create further children for these expansions).
llvm::SmallVector<SourceLocation> EnclosingMacroLoc;
public:
DocumentSymbol build() && {
for (SymBuilder &C : Children) {
Symbol.children.push_back(std::move(C).build());
// Expand range to ensure children nest properly, which editors expect.
// This can fix some edge-cases in the AST, but is vital for macros.
// A macro expansion "contains" AST node if it covers the node's primary
// location, but it may not span the node's whole range.
Symbol.range.start =
std::min(Symbol.range.start, Symbol.children.back().range.start);
Symbol.range.end =
std::max(Symbol.range.end, Symbol.children.back().range.end);
}
return std::move(Symbol);
}
// Add a symbol as a child of the current one.
SymBuilder &addChild(DocumentSymbol S) {
Children.emplace_back();
Children.back().EnclosingMacroLoc = EnclosingMacroLoc;
Children.back().Symbol = std::move(S);
return Children.back();
}
// Get an appropriate container for children of this symbol that were
// expanded from a macro (whose spelled name is Tok).
//
// This may return:
// - a macro symbol child of this (either new or previously created)
// - this scope itself, if it *is* the macro symbol or is nested within it
SymBuilder &inMacro(const syntax::Token &Tok, const SourceManager &SM,
llvm::Optional<syntax::TokenBuffer::Expansion> Exp) {
if (llvm::is_contained(EnclosingMacroLoc, Tok.location()))
return *this;
// If there's an existing child for this macro, we expect it to be last.
if (!Children.empty() && !Children.back().EnclosingMacroLoc.empty() &&
Children.back().EnclosingMacroLoc.back() == Tok.location())
return Children.back();
DocumentSymbol Sym;
Sym.name = Tok.text(SM).str();
Sym.kind = SymbolKind::Null; // There's no suitable kind!
Sym.range = Sym.selectionRange =
halfOpenToRange(SM, Tok.range(SM).toCharRange(SM));
// FIXME: Exp is currently unavailable for nested expansions.
if (Exp) {
// Full range covers the macro args.
Sym.range = halfOpenToRange(SM, CharSourceRange::getCharRange(
Exp->Spelled.front().location(),
Exp->Spelled.back().endLocation()));
// Show macro args as detail.
llvm::raw_string_ostream OS(Sym.detail);
const syntax::Token *Prev = nullptr;
for (const auto &Tok : Exp->Spelled.drop_front()) {
// Don't dump arbitrarily long macro args.
if (OS.tell() > 80) {
OS << " ...)";
break;
}
if (Prev && Prev->endLocation() != Tok.location())
OS << ' ';
OS << Tok.text(SM);
Prev = &Tok;
}
}
SymBuilder &Child = addChild(std::move(Sym));
Child.EnclosingMacroLoc.push_back(Tok.location());
return Child;
}
};
public:
DocumentOutline(ParsedAST &AST) : AST(AST) {}
/// Builds the document outline for the generated AST.
std::vector<DocumentSymbol> build() {
SymBuilder Root;
for (auto &TopLevel : AST.getLocalTopLevelDecls())
traverseDecl(TopLevel, Root);
return std::move(std::move(Root).build().children);
}
private:
enum class VisitKind { No, OnlyDecl, OnlyChildren, DeclAndChildren };
void traverseDecl(Decl *D, SymBuilder &Parent) {
// Skip symbols which do not originate from the main file.
if (!isInsideMainFile(D->getLocation(), AST.getSourceManager()))
return;
if (auto *Templ = llvm::dyn_cast<TemplateDecl>(D)) {
// TemplatedDecl might be null, e.g. concepts.
if (auto *TD = Templ->getTemplatedDecl())
D = TD;
}
VisitKind Visit = shouldVisit(D);
if (Visit == VisitKind::No)
return;
if (Visit == VisitKind::OnlyChildren)
return traverseChildren(D, Parent);
auto *ND = llvm::cast<NamedDecl>(D);
auto Sym = declToSym(AST.getASTContext(), *ND);
if (!Sym)
return;
SymBuilder &MacroParent = possibleMacroContainer(D->getLocation(), Parent);
SymBuilder &Child = MacroParent.addChild(std::move(*Sym));
if (Visit == VisitKind::OnlyDecl)
return;
assert(Visit == VisitKind::DeclAndChildren && "Unexpected VisitKind");
traverseChildren(ND, Child);
}
// Determines where a decl should appear in the DocumentSymbol hierarchy.
//
// This is usually a direct child of the relevant AST parent.
// But we may also insert nodes for macros. Given:
// #define DECLARE_INT(V) int v;
// namespace a { DECLARE_INT(x) }
// We produce:
// Namespace a
// Macro DECLARE_INT(x)
// Variable x
//
// In the absence of macros, this method simply returns Parent.
// Otherwise it may return a macro expansion node instead.
// Each macro only has at most one node in the hierarchy, even if it expands
// to multiple decls.
SymBuilder &possibleMacroContainer(SourceLocation TargetLoc,
SymBuilder &Parent) {
const auto &SM = AST.getSourceManager();
// Look at the path of macro-callers from the token to the main file.
// Note that along these paths we see the "outer" macro calls first.
SymBuilder *CurParent = &Parent;
for (SourceLocation Loc = TargetLoc; Loc.isMacroID();
Loc = SM.getImmediateMacroCallerLoc(Loc)) {
// Find the virtual macro body that our token is being substituted into.
FileID MacroBody;
if (SM.isMacroArgExpansion(Loc)) {
// Loc is part of a macro arg being substituted into a macro body.
MacroBody = SM.getFileID(SM.getImmediateExpansionRange(Loc).getBegin());
} else {
// Loc is already in the macro body.
MacroBody = SM.getFileID(Loc);
}
// The macro body is being substituted for a macro expansion, whose
// first token is the name of the macro.
SourceLocation MacroName =
SM.getSLocEntry(MacroBody).getExpansion().getExpansionLocStart();
// Only include the macro expansion in the outline if it was written
// directly in the main file, rather than expanded from another macro.
if (!MacroName.isValid() || !MacroName.isFileID())
continue;
// All conditions satisfied, add the macro.
if (auto *Tok = AST.getTokens().spelledTokenAt(MacroName))
CurParent = &CurParent->inMacro(
*Tok, SM, AST.getTokens().expansionStartingAt(Tok));
}
return *CurParent;
}
void traverseChildren(Decl *D, SymBuilder &Builder) {
auto *Scope = llvm::dyn_cast<DeclContext>(D);
if (!Scope)
return;
for (auto *C : Scope->decls())
traverseDecl(C, Builder);
}
VisitKind shouldVisit(Decl *D) {
if (D->isImplicit())
return VisitKind::No;
if (llvm::isa<LinkageSpecDecl>(D) || llvm::isa<ExportDecl>(D))
return VisitKind::OnlyChildren;
if (!llvm::isa<NamedDecl>(D))
return VisitKind::No;
if (auto Func = llvm::dyn_cast<FunctionDecl>(D)) {
// Some functions are implicit template instantiations, those should be
// ignored.
if (auto *Info = Func->getTemplateSpecializationInfo()) {
if (!Info->isExplicitInstantiationOrSpecialization())
return VisitKind::No;
}
// Only visit the function itself, do not visit the children (i.e.
// function parameters, etc.)
return VisitKind::OnlyDecl;
}
// Handle template instantiations. We have three cases to consider:
// - explicit instantiations, e.g. 'template class std::vector<int>;'
// Visit the decl itself (it's present in the code), but not the
// children.
// - implicit instantiations, i.e. not written by the user.
// Do not visit at all, they are not present in the code.
// - explicit specialization, e.g. 'template <> class vector<bool> {};'
// Visit both the decl and its children, both are written in the code.
if (auto *TemplSpec = llvm::dyn_cast<ClassTemplateSpecializationDecl>(D)) {
if (TemplSpec->isExplicitInstantiationOrSpecialization())
return TemplSpec->isExplicitSpecialization()
? VisitKind::DeclAndChildren
: VisitKind::OnlyDecl;
return VisitKind::No;
}
if (auto *TemplSpec = llvm::dyn_cast<VarTemplateSpecializationDecl>(D)) {
if (TemplSpec->isExplicitInstantiationOrSpecialization())
return TemplSpec->isExplicitSpecialization()
? VisitKind::DeclAndChildren
: VisitKind::OnlyDecl;
return VisitKind::No;
}
// For all other cases, visit both the children and the decl.
return VisitKind::DeclAndChildren;
}
ParsedAST &AST;
};
std::vector<DocumentSymbol> collectDocSymbols(ParsedAST &AST) {
return DocumentOutline(AST).build();
}
} // namespace
llvm::Expected<std::vector<DocumentSymbol>> getDocumentSymbols(ParsedAST &AST) {
return collectDocSymbols(AST);
}
} // namespace clangd
} // namespace clang
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