1 files changed, 149 insertions, 0 deletions
diff --git a/lib/Tooling/Syntax/Tree.cpp b/lib/Tooling/Syntax/Tree.cpp
new file mode 100644
index 0000000000000..1549b6724fa44
--- /dev/null
+++ b/lib/Tooling/Syntax/Tree.cpp
@@ -0,0 +1,149 @@
+//===- Tree.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 "clang/Tooling/Syntax/Tree.h"
+#include "clang/Basic/TokenKinds.h"
+#include "clang/Tooling/Syntax/Nodes.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Casting.h"
+
+using namespace clang;
+
+syntax::Arena::Arena(SourceManager &SourceMgr, const LangOptions &LangOpts,
+                     TokenBuffer Tokens)
+    : SourceMgr(SourceMgr), LangOpts(LangOpts), Tokens(std::move(Tokens)) {}
+
+const clang::syntax::TokenBuffer &syntax::Arena::tokenBuffer() const {
+  return Tokens;
+}
+
+std::pair<FileID, llvm::ArrayRef<syntax::Token>>
+syntax::Arena::lexBuffer(std::unique_ptr<llvm::MemoryBuffer> Input) {
+  auto FID = SourceMgr.createFileID(std::move(Input));
+  auto It = ExtraTokens.try_emplace(FID, tokenize(FID, SourceMgr, LangOpts));
+  assert(It.second && "duplicate FileID");
+  return {FID, It.first->second};
+}
+
+syntax::Leaf::Leaf(const syntax::Token *Tok) : Node(NodeKind::Leaf), Tok(Tok) {
+  assert(Tok != nullptr);
+}
+
+bool syntax::Leaf::classof(const Node *N) {
+  return N->kind() == NodeKind::Leaf;
+}
+
+syntax::Node::Node(NodeKind Kind)
+    : Parent(nullptr), NextSibling(nullptr), Kind(static_cast<unsigned>(Kind)),
+      Role(static_cast<unsigned>(NodeRole::Detached)) {}
+
+bool syntax::Tree::classof(const Node *N) { return N->kind() > NodeKind::Leaf; }
+
+void syntax::Tree::prependChildLowLevel(Node *Child, NodeRole Role) {
+  assert(Child->Parent == nullptr);
+  assert(Child->NextSibling == nullptr);
+  assert(Child->role() == NodeRole::Detached);
+  assert(Role != NodeRole::Detached);
+
+  Child->Parent = this;
+  Child->NextSibling = this->FirstChild;
+  Child->Role = static_cast<unsigned>(Role);
+  this->FirstChild = Child;
+}
+
+namespace {
+static void traverse(const syntax::Node *N,
+                     llvm::function_ref<void(const syntax::Node *)> Visit) {
+  if (auto *T = dyn_cast<syntax::Tree>(N)) {
+    for (auto *C = T->firstChild(); C; C = C->nextSibling())
+      traverse(C, Visit);
+  }
+  Visit(N);
+}
+static void dumpTokens(llvm::raw_ostream &OS, ArrayRef<syntax::Token> Tokens,
+                       const SourceManager &SM) {
+  assert(!Tokens.empty());
+  bool First = true;
+  for (const auto &T : Tokens) {
+    if (!First)
+      OS << " ";
+    else
+      First = false;
+    // Handle 'eof' separately, calling text() on it produces an empty string.
+    if (T.kind() == tok::eof) {
+      OS << "<eof>";
+      continue;
+    }
+    OS << T.text(SM);
+  }
+}
+
+static void dumpTree(llvm::raw_ostream &OS, const syntax::Node *N,
+                     const syntax::Arena &A, std::vector<bool> IndentMask) {
+  if (N->role() != syntax::NodeRole::Unknown) {
+    // FIXME: print the symbolic name of a role.
+    if (N->role() == syntax::NodeRole::Detached)
+      OS << "*: ";
+    else
+      OS << static_cast<int>(N->role()) << ": ";
+  }
+  if (auto *L = llvm::dyn_cast<syntax::Leaf>(N)) {
+    dumpTokens(OS, *L->token(), A.sourceManager());
+    OS << "\n";
+    return;
+  }
+
+  auto *T = llvm::cast<syntax::Tree>(N);
+  OS << T->kind() << "\n";
+
+  for (auto It = T->firstChild(); It != nullptr; It = It->nextSibling()) {
+    for (bool Filled : IndentMask) {
+      if (Filled)
+        OS << "| ";
+      else
+        OS << "  ";
+    }
+    if (!It->nextSibling()) {
+      OS << "`-";
+      IndentMask.push_back(false);
+    } else {
+      OS << "|-";
+      IndentMask.push_back(true);
+    }
+    dumpTree(OS, It, A, IndentMask);
+    IndentMask.pop_back();
+  }
+}
+} // namespace
+
+std::string syntax::Node::dump(const Arena &A) const {
+  std::string Str;
+  llvm::raw_string_ostream OS(Str);
+  dumpTree(OS, this, A, /*IndentMask=*/{});
+  return std::move(OS.str());
+}
+
+std::string syntax::Node::dumpTokens(const Arena &A) const {
+  std::string Storage;
+  llvm::raw_string_ostream OS(Storage);
+  traverse(this, [&](const syntax::Node *N) {
+    auto *L = llvm::dyn_cast<syntax::Leaf>(N);
+    if (!L)
+      return;
+    ::dumpTokens(OS, *L->token(), A.sourceManager());
+  });
+  return OS.str();
+}
+
+syntax::Node *syntax::Tree::findChild(NodeRole R) {
+  for (auto *C = FirstChild; C; C = C->nextSibling()) {
+    if (C->role() == R)
+      return C;
+  }
+  return nullptr;
+}