[Syntax] Introduce syntax trees

Summary:
A tooling-focused alternative to the AST. This commit focuses on the
memory-management strategy and the structure of the AST.

More to follow later:
  - Operations to mutate the syntax trees and corresponding textual
    replacements.
  - Mapping between clang AST nodes and syntax tree nodes.
  - More node types corresponding to the language constructs.

Reviewers: sammccall

Reviewed By: sammccall

Subscribers: llvm-commits, mgorny, cfe-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D61637

llvm-svn: 365355

1 files changed, 33 insertions, 0 deletions

diff --git a/clang/lib/Tooling/Syntax/Nodes.cpp b/clang/lib/Tooling/Syntax/Nodes.cpp
new file mode 100644
index 00000000000..5dd793ccc2d
--- /dev/null
+++ b/clang/lib/Tooling/Syntax/Nodes.cpp
@@ -0,0 +1,33 @@
+//===- Nodes.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/Nodes.h"
+#include "clang/Basic/TokenKinds.h"
+
+using namespace clang;
+
+llvm::raw_ostream &syntax::operator<<(llvm::raw_ostream &OS, NodeKind K) {
+  switch (K) {
+  case NodeKind::Leaf:
+    return OS << "Leaf";
+  case NodeKind::TranslationUnit:
+    return OS << "TranslationUnit";
+  case NodeKind::TopLevelDeclaration:
+    return OS << "TopLevelDeclaration";
+  case NodeKind::CompoundStatement:
+    return OS << "CompoundStatement";
+  }
+  llvm_unreachable("unknown node kind");
+}
+
+syntax::Leaf *syntax::CompoundStatement::lbrace() {
+  return llvm::cast_or_null<syntax::Leaf>(findChild(Roles::lbrace));
+}
+
+syntax::Leaf *syntax::CompoundStatement::rbrace() {
+  return llvm::cast_or_null<syntax::Leaf>(findChild(Roles::rbrace));
+}