[clangd] findExplicitReferences supports goto labels

Summary:
This means they're renamable and textDocument/highlight works

This fell out of D78454

Reviewers: adamcz

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80170

clang-tools-extra/clangd/FindTarget.cpp

@@ -643,7 +643,7 @@ llvm::SmallVector<ReferenceLoc, 2> refInDecl(const Decl *D) {
   return V.Refs;
 }
 
-llvm::SmallVector<ReferenceLoc, 2> refInExpr(const Expr *E) {
+llvm::SmallVector<ReferenceLoc, 2> refInStmt(const Stmt *S) {
   struct Visitor : ConstStmtVisitor<Visitor> {
     // FIXME: handle more complicated cases: more ObjC, designated initializers.
     llvm::SmallVector<ReferenceLoc, 2> Refs;
@@ -722,10 +722,25 @@ llvm::SmallVector<ReferenceLoc, 2> refInExpr(const Expr *E) {
                                     /*IsDecl=*/false, std::move(Targets)});
       }
     }
+
+    void VisitGotoStmt(const GotoStmt *GS) {
+      llvm::SmallVector<const NamedDecl *, 1> Targets;
+      if (const auto *L = GS->getLabel())
+        Targets.push_back(L);
+      Refs.push_back(ReferenceLoc{NestedNameSpecifierLoc(), GS->getLabelLoc(),
+                                  /*IsDecl=*/false, std::move(Targets)});
+    }
+
+    void VisitLabelStmt(const LabelStmt *LS) {
+      Refs.push_back(ReferenceLoc{NestedNameSpecifierLoc(),
+                                  LS->getIdentLoc(),
+                                  /*IsDecl=*/true,
+                                  {LS->getDecl()}});
+    }
   };
 
   Visitor V;
-  V.Visit(E);
+  V.Visit(S);
   return V.Refs;
 }
 
@@ -837,8 +852,8 @@ class ExplicitReferenceCollector
     return RecursiveASTVisitor::TraverseElaboratedTypeLoc(L);
   }
 
-  bool VisitExpr(Expr *E) {
-    visitNode(DynTypedNode::create(*E));
+  bool VisitStmt(Stmt *S) {
+    visitNode(DynTypedNode::create(*S));
     return true;
   }
 
@@ -926,8 +941,8 @@ class ExplicitReferenceCollector
   llvm::SmallVector<ReferenceLoc, 2> explicitReference(DynTypedNode N) {
     if (auto *D = N.get<Decl>())
       return refInDecl(D);
-    if (auto *E = N.get<Expr>())
-      return refInExpr(E);
+    if (auto *S = N.get<Stmt>())
+      return refInStmt(S);
     if (auto *NNSL = N.get<NestedNameSpecifierLoc>()) {
       // (!) 'DeclRelation::Alias' ensures we do not loose namespace aliases.
       return {ReferenceLoc{

clang-tools-extra/clangd/unittests/FindTargetTests.cpp

@@ -786,6 +786,14 @@ TEST_F(FindExplicitReferencesTest, All) {
         "6: targets = {a::b::S}\n"
         "7: targets = {a::b::S::type}, qualifier = 'struct S::'\n"
         "8: targets = {y}, decl\n"},
+       {R"cpp(
+         void foo() {
+           $0^ten: // PRINT "HELLO WORLD!"
+           goto $1^ten;
+         }
+       )cpp",
+       "0: targets = {ten}, decl\n"
+       "1: targets = {ten}\n"},
        // Simple templates.
        {R"cpp(
           template <class T> struct vector { using value_type = T; };