Revert rL365355 : [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
........
Fixes buildbots which were crashing on SyntaxTests.exe

llvm-svn: 365465

1 files changed, 0 insertions, 271 deletions

diff --git a/clang/lib/Tooling/Syntax/BuildTree.cpp b/clang/lib/Tooling/Syntax/BuildTree.cpp
deleted file mode 100644
index dc682ff677f..00000000000
--- a/clang/lib/Tooling/Syntax/BuildTree.cpp
+++ /dev/null
@@ -1,271 +0,0 @@
-//===- BuildTree.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/BuildTree.h"
-#include "clang/AST/RecursiveASTVisitor.h"
-#include "clang/AST/Stmt.h"
-#include "clang/Basic/LLVM.h"
-#include "clang/Basic/SourceLocation.h"
-#include "clang/Basic/SourceManager.h"
-#include "clang/Basic/TokenKinds.h"
-#include "clang/Lex/Lexer.h"
-#include "clang/Tooling/Syntax/Nodes.h"
-#include "clang/Tooling/Syntax/Tokens.h"
-#include "clang/Tooling/Syntax/Tree.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/Support/Allocator.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/FormatVariadic.h"
-#include "llvm/Support/raw_ostream.h"
-#include <map>
-
-using namespace clang;
-
-/// A helper class for constructing the syntax tree while traversing a clang
-/// AST.
-///
-/// At each point of the traversal we maintain a list of pending nodes.
-/// Initially all tokens are added as pending nodes. When processing a clang AST
-/// node, the clients need to:
-///   - create a corresponding syntax node,
-///   - assign roles to all pending child nodes with 'markChild' and
-///     'markChildToken',
-///   - replace the child nodes with the new syntax node in the pending list
-///     with 'foldNode'.
-///
-/// Note that all children are expected to be processed when building a node.
-///
-/// Call finalize() to finish building the tree and consume the root node.
-class syntax::TreeBuilder {
-public:
-  TreeBuilder(syntax::Arena &Arena) : Arena(Arena), Pending(Arena) {}
-
-  llvm::BumpPtrAllocator &allocator() { return Arena.allocator(); }
-
-  /// Populate children for \p New node, assuming it covers tokens from \p
-  /// Range.
-  void foldNode(llvm::ArrayRef<syntax::Token> Range, syntax::Tree *New);
-
-  /// Set role for a token starting at \p Loc.
-  void markChildToken(SourceLocation Loc, tok::TokenKind Kind, NodeRole R);
-
-  /// Finish building the tree and consume the root node.
-  syntax::TranslationUnit *finalize() && {
-    auto Tokens = Arena.tokenBuffer().expandedTokens();
-    // Build the root of the tree, consuming all the children.
-    Pending.foldChildren(Tokens,
-                         new (Arena.allocator()) syntax::TranslationUnit);
-
-    return cast<syntax::TranslationUnit>(std::move(Pending).finalize());
-  }
-
-  /// getRange() finds the syntax tokens corresponding to the passed source
-  /// locations.
-  /// \p First is the start position of the first token and \p Last is the start
-  /// position of the last token.
-  llvm::ArrayRef<syntax::Token> getRange(SourceLocation First,
-                                         SourceLocation Last) const {
-    assert(First.isValid());
-    assert(Last.isValid());
-    assert(First == Last ||
-           Arena.sourceManager().isBeforeInTranslationUnit(First, Last));
-    return llvm::makeArrayRef(findToken(First), std::next(findToken(Last)));
-  }
-  llvm::ArrayRef<syntax::Token> getRange(const Decl *D) const {
-    return getRange(D->getBeginLoc(), D->getEndLoc());
-  }
-  llvm::ArrayRef<syntax::Token> getRange(const Stmt *S) const {
-    return getRange(S->getBeginLoc(), S->getEndLoc());
-  }
-
-private:
-  /// Finds a token starting at \p L. The token must exist.
-  const syntax::Token *findToken(SourceLocation L) const;
-
-  /// A collection of trees covering the input tokens.
-  /// When created, each tree corresponds to a single token in the file.
-  /// Clients call 'foldChildren' to attach one or more subtrees to a parent
-  /// node and update the list of trees accordingly.
-  ///
-  /// Ensures that added nodes properly nest and cover the whole token stream.
-  struct Forest {
-    Forest(syntax::Arena &A) {
-      // FIXME: do not add 'eof' to the tree.
-
-      // Create all leaf nodes.
-      for (auto &T : A.tokenBuffer().expandedTokens())
-        Trees.insert(Trees.end(),
-                     {&T, NodeAndRole{new (A.allocator()) syntax::Leaf(&T)}});
-    }
-
-    void assignRole(llvm::ArrayRef<syntax::Token> Range,
-                    syntax::NodeRole Role) {
-      assert(!Range.empty());
-      auto It = Trees.lower_bound(Range.begin());
-      assert(It != Trees.end() && "no node found");
-      assert(It->first == Range.begin() && "no child with the specified range");
-      assert((std::next(It) == Trees.end() ||
-              std::next(It)->first == Range.end()) &&
-             "no child with the specified range");
-      It->second.Role = Role;
-    }
-
-    /// Add \p Node to the forest and fill its children nodes based on the \p
-    /// NodeRange.
-    void foldChildren(llvm::ArrayRef<syntax::Token> NodeTokens,
-                      syntax::Tree *Node) {
-      assert(!NodeTokens.empty());
-      assert(Node->firstChild() == nullptr && "node already has children");
-
-      auto *FirstToken = NodeTokens.begin();
-      auto BeginChildren = Trees.lower_bound(FirstToken);
-      assert(BeginChildren != Trees.end() &&
-             BeginChildren->first == FirstToken &&
-             "fold crosses boundaries of existing subtrees");
-      auto EndChildren = Trees.lower_bound(NodeTokens.end());
-      assert((EndChildren == Trees.end() ||
-              EndChildren->first == NodeTokens.end()) &&
-             "fold crosses boundaries of existing subtrees");
-
-      // (!) we need to go in reverse order, because we can only prepend.
-      for (auto It = EndChildren; It != BeginChildren; --It)
-        Node->prependChildLowLevel(std::prev(It)->second.Node,
-                                   std::prev(It)->second.Role);
-
-      Trees.erase(BeginChildren, EndChildren);
-      Trees.insert({FirstToken, NodeAndRole(Node)});
-    }
-
-    // EXPECTS: all tokens were consumed and are owned by a single root node.
-    syntax::Node *finalize() && {
-      assert(Trees.size() == 1);
-      auto *Root = Trees.begin()->second.Node;
-      Trees = {};
-      return Root;
-    }
-
-    std::string str(const syntax::Arena &A) const {
-      std::string R;
-      for (auto It = Trees.begin(); It != Trees.end(); ++It) {
-        unsigned CoveredTokens =
-            It != Trees.end()
-                ? (std::next(It)->first - It->first)
-                : A.tokenBuffer().expandedTokens().end() - It->first;
-
-        R += llvm::formatv("- '{0}' covers '{1}'+{2} tokens\n",
-                           It->second.Node->kind(),
-                           It->first->text(A.sourceManager()), CoveredTokens);
-        R += It->second.Node->dump(A);
-      }
-      return R;
-    }
-
-  private:
-    /// A with a role that should be assigned to it when adding to a parent.
-    struct NodeAndRole {
-      explicit NodeAndRole(syntax::Node *Node)
-          : Node(Node), Role(NodeRoleUnknown) {}
-
-      syntax::Node *Node;
-      NodeRole Role;
-    };
-
-    /// Maps from the start token to a subtree starting at that token.
-    /// FIXME: storing the end tokens is redundant.
-    /// FIXME: the key of a map is redundant, it is also stored in NodeForRange.
-    std::map<const syntax::Token *, NodeAndRole> Trees;
-  };
-
-  /// For debugging purposes.
-  std::string str() { return Pending.str(Arena); }
-
-  syntax::Arena &Arena;
-  Forest Pending;
-};
-
-namespace {
-class BuildTreeVisitor : public RecursiveASTVisitor<BuildTreeVisitor> {
-public:
-  explicit BuildTreeVisitor(ASTContext &Ctx, syntax::TreeBuilder &Builder)
-      : Builder(Builder), LangOpts(Ctx.getLangOpts()) {}
-
-  bool shouldTraversePostOrder() const { return true; }
-
-  bool TraverseDecl(Decl *D) {
-    if (!D || isa<TranslationUnitDecl>(D))
-      return RecursiveASTVisitor::TraverseDecl(D);
-    if (!llvm::isa<TranslationUnitDecl>(D->getDeclContext()))
-      return true; // Only build top-level decls for now, do not recurse.
-    return RecursiveASTVisitor::TraverseDecl(D);
-  }
-
-  bool VisitDecl(Decl *D) {
-    assert(llvm::isa<TranslationUnitDecl>(D->getDeclContext()) &&
-           "expected a top-level decl");
-    assert(!D->isImplicit());
-    Builder.foldNode(Builder.getRange(D),
-                     new (allocator()) syntax::TopLevelDeclaration());
-    return true;
-  }
-
-  bool WalkUpFromTranslationUnitDecl(TranslationUnitDecl *TU) {
-    // (!) we do not want to call VisitDecl(), the declaration for translation
-    // unit is built by finalize().
-    return true;
-  }
-
-  bool WalkUpFromCompoundStmt(CompoundStmt *S) {
-    using Roles = syntax::CompoundStatement::Roles;
-
-    Builder.markChildToken(S->getLBracLoc(), tok::l_brace, Roles::lbrace);
-    Builder.markChildToken(S->getRBracLoc(), tok::r_brace, Roles::rbrace);
-
-    Builder.foldNode(Builder.getRange(S),
-                     new (allocator()) syntax::CompoundStatement);
-    return true;
-  }
-
-private:
-  /// A small helper to save some typing.
-  llvm::BumpPtrAllocator &allocator() { return Builder.allocator(); }
-
-  syntax::TreeBuilder &Builder;
-  const LangOptions &LangOpts;
-};
-} // namespace
-
-void syntax::TreeBuilder::foldNode(llvm::ArrayRef<syntax::Token> Range,
-                                   syntax::Tree *New) {
-  Pending.foldChildren(Range, New);
-}
-
-void syntax::TreeBuilder::markChildToken(SourceLocation Loc,
-                                         tok::TokenKind Kind, NodeRole Role) {
-  if (Loc.isInvalid())
-    return;
-  Pending.assignRole(*findToken(Loc), Role);
-}
-
-const syntax::Token *syntax::TreeBuilder::findToken(SourceLocation L) const {
-  auto Tokens = Arena.tokenBuffer().expandedTokens();
-  auto &SM = Arena.sourceManager();
-  auto It = llvm::partition_point(Tokens, [&](const syntax::Token &T) {
-    return SM.isBeforeInTranslationUnit(T.location(), L);
-  });
-  assert(It != Tokens.end());
-  assert(It->location() == L);
-  return &*It;
-}
-
-syntax::TranslationUnit *
-syntax::buildSyntaxTree(Arena &A, const TranslationUnitDecl &TU) {
-  TreeBuilder Builder(A);
-  BuildTreeVisitor(TU.getASTContext(), Builder).TraverseAST(TU.getASTContext());
-  return std::move(Builder).finalize();
-}