[clangd] Add semantic token for labels

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D143260

clang-tools-extra/clangd/SemanticHighlighting.cpp

@@ -166,6 +166,8 @@ std::optional<HighlightingKind> kindForDecl(const NamedDecl *D,
     return HighlightingKind::TemplateParameter;
   if (isa<ConceptDecl>(D))
     return HighlightingKind::Concept;
+  if (isa<LabelDecl>(D))
+    return HighlightingKind::Label;
   if (const auto *UUVD = dyn_cast<UnresolvedUsingValueDecl>(D)) {
     auto Targets = Resolver->resolveUsingValueDecl(UUVD);
     if (!Targets.empty() && Targets[0] != UUVD) {
@@ -1271,6 +1273,8 @@ llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, HighlightingKind K) {
     return OS << "Operator";
   case HighlightingKind::Bracket:
     return OS << "Bracket";
+  case HighlightingKind::Label:
+    return OS << "Label";
   case HighlightingKind::InactiveCode:
     return OS << "InactiveCode";
   }
@@ -1470,6 +1474,8 @@ llvm::StringRef toSemanticTokenType(HighlightingKind Kind) {
     return "operator";
   case HighlightingKind::Bracket:
     return "bracket";
+  case HighlightingKind::Label:
+    return "label";
   case HighlightingKind::InactiveCode:
     return "comment";
   }

clang-tools-extra/clangd/SemanticHighlighting.h

@@ -52,6 +52,7 @@ enum class HighlightingKind {
   Modifier,
   Operator,
   Bracket,
+  Label,
 
   // This one is different from the other kinds as it's a line style
   // rather than a token style.

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

@@ -1028,6 +1028,16 @@ $Bracket[[>]]$Bracket[[>]] $LocalVariable_def[[s6]];
         template $Bracket[[<]]$Concept[[C2]]$Bracket[[<]]int$Bracket[[>]] $TemplateParameter_def[[A]]$Bracket[[>]]
         class $Class_def[[B]] {};
       )cpp",
+      // Labels
+      R"cpp(
+        bool $Function_def[[funcWithGoto]](bool $Parameter_def[[b]]) {
+          if ($Parameter[[b]])
+            goto $Label[[return_true]];
+          return false;
+          $Label_decl[[return_true]]:
+            return true;
+        }
+      )cpp",
       // no crash
       R"cpp(
         struct $Class_def[[Foo]] {