utils/TableGen/ClangASTNodesEmitter.cpp

//=== ClangASTNodesEmitter.cpp - Generate Clang AST node tables -*- 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
//
//===----------------------------------------------------------------------===//
//
// These tablegen backends emit Clang AST node tables
//
//===----------------------------------------------------------------------===//

#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
#include <cctype>
#include <map>
#include <set>
#include <string>
using namespace llvm;

/// ClangASTNodesEmitter - The top-level class emits .inc files containing
///  declarations of Clang statements.
///
namespace {
class ClangASTNodesEmitter {
  // A map from a node to each of its derived nodes.
  typedef std::multimap<Record*, Record*> ChildMap;
  typedef ChildMap::const_iterator ChildIterator;

  RecordKeeper &Records;
  Record Root;
  const std::string &BaseSuffix;

  // Create a macro-ized version of a name
  static std::string macroName(std::string S) {
    for (unsigned i = 0; i < S.size(); ++i)
      S[i] = std::toupper(S[i]);

    return S;
  }

  // Return the name to be printed in the base field. Normally this is
  // the record's name plus the base suffix, but if it is the root node and
  // the suffix is non-empty, it's just the suffix.
  std::string baseName(Record &R) {
    if (&R == &Root && !BaseSuffix.empty())
      return BaseSuffix;

    return R.getName().str() + BaseSuffix;
  }

  std::pair<Record *, Record *> EmitNode (const ChildMap &Tree, raw_ostream& OS,
                                          Record *Base);
public:
  explicit ClangASTNodesEmitter(RecordKeeper &R, const std::string &N,
                                const std::string &S)
    : Records(R), Root(N, SMLoc(), R), BaseSuffix(S)
    {}

  // run - Output the .inc file contents
  void run(raw_ostream &OS);
};
} // end anonymous namespace

//===----------------------------------------------------------------------===//
// Statement Node Tables (.inc file) generation.
//===----------------------------------------------------------------------===//

// Returns the first and last non-abstract subrecords
// Called recursively to ensure that nodes remain contiguous
std::pair<Record *, Record *> ClangASTNodesEmitter::EmitNode(
                                                           const ChildMap &Tree,
                                                           raw_ostream &OS,
                                                           Record *Base) {
  std::string BaseName = macroName(Base->getName());

  ChildIterator i = Tree.lower_bound(Base), e = Tree.upper_bound(Base);

  Record *First = nullptr, *Last = nullptr;
  // This might be the pseudo-node for Stmt; don't assume it has an Abstract
  // bit
  if (Base->getValue("Abstract") && !Base->getValueAsBit("Abstract"))
    First = Last = Base;

  for (; i != e; ++i) {
    Record *R = i->second;
    bool Abstract = R->getValueAsBit("Abstract");
    std::string NodeName = macroName(R->getName());

    OS << "#ifndef " << NodeName << "\n";
    OS << "#  define " << NodeName << "(Type, Base) "
        << BaseName << "(Type, Base)\n";
    OS << "#endif\n";

    if (Abstract)
      OS << "ABSTRACT_" << macroName(Root.getName()) << "(" << NodeName << "("
          << R->getName() << ", " << baseName(*Base) << "))\n";
    else
      OS << NodeName << "(" << R->getName() << ", "
          << baseName(*Base) << ")\n";

    if (Tree.find(R) != Tree.end()) {
      const std::pair<Record *, Record *> &Result
        = EmitNode(Tree, OS, R);
      if (!First && Result.first)
        First = Result.first;
      if (Result.second)
        Last = Result.second;
    } else {
      if (!Abstract) {
        Last = R;

        if (!First)
          First = R;
      }
    }

    OS << "#undef " << NodeName << "\n\n";
  }

  if (First) {
    assert (Last && "Got a first node but not a last node for a range!");
    if (Base == &Root)
      OS << "LAST_" << macroName(Root.getName()) << "_RANGE(";
    else
      OS << macroName(Root.getName()) << "_RANGE(";
    OS << Base->getName() << ", " << First->getName() << ", "
       << Last->getName() << ")\n\n";
  }

  return std::make_pair(First, Last);
}

void ClangASTNodesEmitter::run(raw_ostream &OS) {
  emitSourceFileHeader("List of AST nodes of a particular kind", OS);

  // Write the preamble
  OS << "#ifndef ABSTRACT_" << macroName(Root.getName()) << "\n";
  OS << "#  define ABSTRACT_" << macroName(Root.getName()) << "(Type) Type\n";
  OS << "#endif\n";

  OS << "#ifndef " << macroName(Root.getName()) << "_RANGE\n";
  OS << "#  define "
     << macroName(Root.getName()) << "_RANGE(Base, First, Last)\n";
  OS << "#endif\n\n";

  OS << "#ifndef LAST_" << macroName(Root.getName()) << "_RANGE\n";
  OS << "#  define LAST_"
     << macroName(Root.getName()) << "_RANGE(Base, First, Last) "
     << macroName(Root.getName()) << "_RANGE(Base, First, Last)\n";
  OS << "#endif\n\n";

  // Emit statements
  const std::vector<Record*> Stmts
    = Records.getAllDerivedDefinitions(Root.getName());

  ChildMap Tree;

  for (unsigned i = 0, e = Stmts.size(); i != e; ++i) {
    Record *R = Stmts[i];

    if (R->getValue("Base"))
      Tree.insert(std::make_pair(R->getValueAsDef("Base"), R));
    else
      Tree.insert(std::make_pair(&Root, R));
  }

  EmitNode(Tree, OS, &Root);

  OS << "#undef " << macroName(Root.getName()) << "\n";
  OS << "#undef " << macroName(Root.getName()) << "_RANGE\n";
  OS << "#undef LAST_" << macroName(Root.getName()) << "_RANGE\n";
  OS << "#undef ABSTRACT_" << macroName(Root.getName()) << "\n";
}

namespace clang {
void EmitClangASTNodes(RecordKeeper &RK, raw_ostream &OS,
                       const std::string &N, const std::string &S) {
  ClangASTNodesEmitter(RK, N, S).run(OS);
}

// Emits and addendum to a .inc file to enumerate the clang declaration
// contexts.
void EmitClangDeclContext(RecordKeeper &Records, raw_ostream &OS) {
  // FIXME: Find a .td file format to allow for this to be represented better.

  emitSourceFileHeader("List of AST Decl nodes", OS);

  OS << "#ifndef DECL_CONTEXT\n";
  OS << "#  define DECL_CONTEXT(DECL)\n";
  OS << "#endif\n";

  OS << "#ifndef DECL_CONTEXT_BASE\n";
  OS << "#  define DECL_CONTEXT_BASE(DECL) DECL_CONTEXT(DECL)\n";
  OS << "#endif\n";

  typedef std::set<Record*> RecordSet;
  typedef std::vector<Record*> RecordVector;

  RecordVector DeclContextsVector
    = Records.getAllDerivedDefinitions("DeclContext");
  RecordVector Decls = Records.getAllDerivedDefinitions("Decl");
  RecordSet DeclContexts (DeclContextsVector.begin(), DeclContextsVector.end());

  for (RecordVector::iterator i = Decls.begin(), e = Decls.end(); i != e; ++i) {
    Record *R = *i;

    if (R->getValue("Base")) {
      Record *B = R->getValueAsDef("Base");
      if (DeclContexts.find(B) != DeclContexts.end()) {
        OS << "DECL_CONTEXT_BASE(" << B->getName() << ")\n";
        DeclContexts.erase(B);
      }
    }
  }

  // To keep identical order, RecordVector may be used
  // instead of RecordSet.
  for (RecordVector::iterator
         i = DeclContextsVector.begin(), e = DeclContextsVector.end();
       i != e; ++i)
    if (DeclContexts.find(*i) != DeclContexts.end())
      OS << "DECL_CONTEXT(" << (*i)->getName() << ")\n";

  OS << "#undef DECL_CONTEXT\n";
  OS << "#undef DECL_CONTEXT_BASE\n";
}
} // end namespace clang