[clangd] Add support for hierarchical documentSymbol

Reviewers: ioeric, sammccall, simark

Reviewed By: sammccall

Subscribers: MaskRay, jkorous, arphaman, kadircet, cfe-commits

Differential Revision: https://reviews.llvm.org/D52311

llvm-svn: 347498

1 files changed, 43 insertions, 0 deletions

diff --git a/clang-tools-extra/clangd/AST.cpp b/clang-tools-extra/clangd/AST.cpp
index 12c8f9f7a5d..e9cf2ffe9d1 100644
--- a/clang-tools-extra/clangd/AST.cpp
+++ b/clang-tools-extra/clangd/AST.cpp
@@ -11,9 +11,12 @@
 
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Decl.h"
+#include "clang/AST/DeclTemplate.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Index/USRGeneration.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/ScopedPrinter.h"
 
 using namespace llvm;
 namespace clang {
@@ -61,6 +64,46 @@ std::string printQualifiedName(const NamedDecl &ND) {
   return QName;
 }
 
+static const TemplateArgumentList *
+getTemplateSpecializationArgs(const NamedDecl &ND) {
+  if (auto *Func = llvm::dyn_cast<FunctionDecl>(&ND))
+    return Func->getTemplateSpecializationArgs();
+  if (auto *Cls = llvm::dyn_cast<ClassTemplateSpecializationDecl>(&ND))
+    return &Cls->getTemplateInstantiationArgs();
+  if (auto *Var = llvm::dyn_cast<VarTemplateSpecializationDecl>(&ND))
+    return &Var->getTemplateInstantiationArgs();
+  return nullptr;
+}
+
+std::string printName(const ASTContext &Ctx, const NamedDecl &ND) {
+  std::string Name;
+  llvm::raw_string_ostream Out(Name);
+  PrintingPolicy PP(Ctx.getLangOpts());
+  // Handle 'using namespace'. They all have the same name - <using-directive>.
+  if (auto *UD = llvm::dyn_cast<UsingDirectiveDecl>(&ND)) {
+    Out << "using namespace ";
+    if (auto *Qual = UD->getQualifier())
+      Qual->print(Out, PP);
+    UD->getNominatedNamespaceAsWritten()->printName(Out);
+    return Out.str();
+  }
+  ND.getDeclName().print(Out, PP);
+  if (!Out.str().empty()) {
+    // FIXME(ibiryukov): do not show args not explicitly written by the user.
+    if (auto *ArgList = getTemplateSpecializationArgs(ND))
+      printTemplateArgumentList(Out, ArgList->asArray(), PP);
+    return Out.str();
+  }
+  // The name was empty, so present an anonymous entity.
+  if (auto *NS = llvm::dyn_cast<NamespaceDecl>(&ND))
+    return "(anonymous namespace)";
+  if (auto *Cls = llvm::dyn_cast<RecordDecl>(&ND))
+    return ("(anonymous " + Cls->getKindName() + ")").str();
+  if (auto *En = llvm::dyn_cast<EnumDecl>(&ND))
+    return "(anonymous enum)";
+  return "(anonymous)";
+}
+
 std::string printNamespaceScope(const DeclContext &DC) {
   for (const auto *Ctx = &DC; Ctx != nullptr; Ctx = Ctx->getParent())
     if (const auto *NS = dyn_cast<NamespaceDecl>(Ctx))