//=== 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 "ASTTableGen.h"

#include "TableGenBackends.h"

#include "llvm/TableGen/Error.h"

#include "llvm/TableGen/Record.h"

#include "llvm/TableGen/TableGenBackend.h"

#include <cctype>

#include <map>

#include <set>

#include <string>

using namespace llvm;

using namespace clang;

using namespace clang::tblgen;

/// 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<ASTNode, ASTNode> ChildMap;

  typedef ChildMap::const_iterator ChildIterator;

  RecordKeeper &Records;

  ASTNode Root;

  const std::string &NodeClassName;

  const std::string &BaseSuffix;

  std::string MacroHierarchyName;

  ChildMap Tree;

  // 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;

  }

  const std::string &macroHierarchyName() {

    assert(Root && "root node not yet derived!");

    if (MacroHierarchyName.empty())

      MacroHierarchyName = macroName(std::string(Root.getName()));

    return MacroHierarchyName;

  }

  // 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(ASTNode node) {

    if (node == Root && !BaseSuffix.empty())

      return BaseSuffix;

    return node.getName().str() + BaseSuffix;

  }

  void deriveChildTree();

  std::pair<ASTNode, ASTNode> EmitNode(raw_ostream& OS, ASTNode Base);

public:

  explicit ClangASTNodesEmitter(RecordKeeper &R, const std::string &N,

                                const std::string &S)

    : Records(R), NodeClassName(N), 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<ASTNode, ASTNode> ClangASTNodesEmitter::EmitNode(raw_ostream &OS,

                                                           ASTNode Base) {

  std::string BaseName = macroName(std::string(Base.getName()));

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

  bool HasChildren = (i != e);

  ASTNode First, Last;

  if (!Base.isAbstract())

    First = Last = Base;

  for (; i != e; ++i) {

    ASTNode Child = i->second;

    bool Abstract = Child.isAbstract();

    std::string NodeName = macroName(std::string(Child.getName()));

    OS << "#ifndef " << NodeName << "\n";

    OS << "#  define " << NodeName << "(Type, Base) "

        << BaseName << "(Type, Base)\n";

    OS << "#endif\n";

    if (Abstract) OS << "ABSTRACT_" << macroHierarchyName() << "(";

    OS << NodeName << "(" << Child.getName() << ", " << baseName(Base) << ")";

    if (Abstract) OS << ")";

    OS << "\n";

    auto Result = EmitNode(OS, Child);

    assert(Result.first && Result.second && "node didn't have children?");

    // Update the range of Base.

    if (!First) First = Result.first;

    Last = Result.second;

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

  }

  // If there aren't first/last nodes, it must be because there were no

  // children and this node was abstract, which is not a sensible combination.

  if (!First) {

    PrintFatalError(Base.getLoc(), "abstract node has no children");

  }

  assert(Last && "set First without Last");

  if (HasChildren) {

    // Use FOO_RANGE unless this is the last of the ranges, in which case

    // use LAST_FOO_RANGE.

    if (Base == Root)

      OS << "LAST_" << macroHierarchyName() << "_RANGE(";

    else

      OS << macroHierarchyName() << "_RANGE(";

    OS << Base.getName() << ", " << First.getName() << ", "

       << Last.getName() << ")\n\n";

  }

  return std::make_pair(First, Last);

}

void ClangASTNodesEmitter::deriveChildTree() {

  assert(!Root && "already computed tree");

  // Emit statements

  const std::vector<Record*> Stmts

    = Records.getAllDerivedDefinitions(NodeClassName);

  for (unsigned i = 0, e = Stmts.size(); i != e; ++i) {

    Record *R = Stmts[i];

    if (auto B = R->getValueAsOptionalDef(BaseFieldName))

      Tree.insert(std::make_pair(B, R));

    else if (Root)

      PrintFatalError(R->getLoc(),

                      Twine("multiple root nodes in \"") + NodeClassName

                        + "\" hierarchy");

    else

      Root = R;

  }

  if (!Root)

    PrintFatalError(Twine("didn't find root node in \"") + NodeClassName

                      + "\" hierarchy");

}

void ClangASTNodesEmitter::run(raw_ostream &OS) {

  deriveChildTree();

  emitSourceFileHeader("List of AST nodes of a particular kind", OS);

  // Write the preamble

  OS << "#ifndef ABSTRACT_" << macroHierarchyName() << "\n";

  OS << "#  define ABSTRACT_" << macroHierarchyName() << "(Type) Type\n";

  OS << "#endif\n";

  OS << "#ifndef " << macroHierarchyName() << "_RANGE\n";

  OS << "#  define "

     << macroHierarchyName() << "_RANGE(Base, First, Last)\n";

  OS << "#endif\n\n";

  OS << "#ifndef LAST_" << macroHierarchyName() << "_RANGE\n";

  OS << "#  define LAST_" 

     << macroHierarchyName() << "_RANGE(Base, First, Last) " 

     << macroHierarchyName() << "_RANGE(Base, First, Last)\n";

  OS << "#endif\n\n";

  EmitNode(OS, Root);

  OS << "#undef " << macroHierarchyName() << "\n";

  OS << "#undef " << macroHierarchyName() << "_RANGE\n";

  OS << "#undef LAST_" << macroHierarchyName() << "_RANGE\n";

  OS << "#undef ABSTRACT_" << macroHierarchyName() << "\n";

}

void clang::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 clang::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(DeclContextNodeClassName);

  RecordVector Decls = Records.getAllDerivedDefinitions(DeclNodeClassName);

  RecordSet DeclContexts (DeclContextsVector.begin(), DeclContextsVector.end());

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

    Record *R = *i;

    if (Record *B = R->getValueAsOptionalDef(BaseFieldName)) {

      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";

}