[clangd] Remove ReferenceFinder::Reference::Target

[nridge]

Summary

No one was using it

[kadircet]

thanks, lgtm!

clang-tools-extra/clangd/XRefs.cpp

869–870

nit: TargetDecls.insert(ND->getCanonicalDecl()) directly, and drop the braces.

897

nit: if (!TargetDecls.contains(D->getCanonicalDecl())

[nridge]

address nits

clang-tools-extra/clangd/XRefs.cpp

 namespace {
 
 /// Collects references to symbols within the main file.
 class ReferenceFinder : public index::IndexDataConsumer {
 public:
   struct Reference {
     syntax::Token SpelledTok;
     index::SymbolRoleSet Role;
-    SymbolID Target;
 
     Range range(const SourceManager &SM) const {
       return halfOpenToRange(SM, SpelledTok.range(SM).toCharRange(SM));
     }
   };
 
   ReferenceFinder(const ParsedAST &AST,
                   const llvm::ArrayRef<const NamedDecl *> Targets,
                   bool PerToken)
       : PerToken(PerToken), AST(AST) {
-    for (const NamedDecl *ND : Targets) {
-      const Decl *CD = ND->getCanonicalDecl();
-      TargetDeclToID[CD] = getSymbolID(CD);
-    }
+    for (const NamedDecl *ND : Targets)
+      TargetDecls.insert(ND->getCanonicalDecl());
   }
 
   std::vector<Reference> take() && {
     llvm::sort(References, [](const Reference &L, const Reference &R) {
       auto LTok = L.SpelledTok.location();
       auto RTok = R.SpelledTok.location();
       return std::tie(LTok, L.Role) < std::tie(RTok, R.Role);
     });
std::vector<Reference> take() && {
     return std::move(References);
   }
 
   bool
   handleDeclOccurrence(const Decl *D, index::SymbolRoleSet Roles,
                        llvm::ArrayRef<index::SymbolRelation> Relations,
                        SourceLocation Loc,
                        index::IndexDataConsumer::ASTNodeInfo ASTNode) override {
-    auto DeclID = TargetDeclToID.find(D->getCanonicalDecl());
-    if (DeclID == TargetDeclToID.end())
+    if (!TargetDecls.contains(D->getCanonicalDecl()))
       return true;
     const SourceManager &SM = AST.getSourceManager();
     if (!isInsideMainFile(Loc, SM))
       return true;
     const auto &TB = AST.getTokens();
 
     llvm::SmallVector<SourceLocation, 1> Locs;
     if (PerToken) {
if (PerToken) {
         Locs.clear(); // First token doesn't match, assume our guess was wrong.
     }
     if (Locs.empty())
       Locs.push_back(Loc);
 
     for (SourceLocation L : Locs) {
       L = SM.getFileLoc(L);
       if (const auto *Tok = TB.spelledTokenAt(L))
-        References.push_back({*Tok, Roles, DeclID->getSecond()});
+        References.push_back({*Tok, Roles});
     }
     return true;
   }
 
 private:
   bool PerToken; // If true, report 3 references for split ObjC selector names.
   std::vector<Reference> References;
   const ParsedAST &AST;
-  llvm::DenseMap<const Decl *, SymbolID> TargetDeclToID;
+  llvm::DenseSet<const Decl *> TargetDecls;
 };
 
 std::vector<ReferenceFinder::Reference>
 findRefs(const llvm::ArrayRef<const NamedDecl *> TargetDecls, ParsedAST &AST,
          bool PerToken) {
   ReferenceFinder RefFinder(AST, TargetDecls, PerToken);
   index::IndexingOptions IndexOpts;
   IndexOpts.SystemSymbolFilter =