utils/TableGen/ClangAttrEmitter.cpp

//===- ClangAttrEmitter.cpp - Generate Clang attribute handling =-*- C++ -*--=//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// These tablegen backends emit Clang attribute processing code
//
//===----------------------------------------------------------------------===//

#include "ClangAttrEmitter.h"
#include "Record.h"
#include "llvm/ADT/StringSwitch.h"
#include <algorithm>
#include <cctype>

using namespace llvm;

static const std::vector<StringRef> getValueAsListOfStrings(Record &R,
                                                            StringRef FieldName) {
  ListInit *List = R.getValueAsListInit(FieldName);
  assert (List && "Got a null ListInit");

  std::vector<StringRef> Strings;
  Strings.reserve(List->getSize());

  for (ListInit::iterator i = List->begin(), e = List->end(); i != e; ++i) {
    assert(*i && "Got a null element in a ListInit");
    if (StringInit *S = dynamic_cast<StringInit *>(*i))
      Strings.push_back(S->getValue());
    else if (CodeInit *C = dynamic_cast<CodeInit *>(*i))
      Strings.push_back(C->getValue());
    else
      assert(false && "Got a non-string, non-code element in a ListInit");
  }

  return Strings;
}

std::string ReadPCHRecord(StringRef type) {
  return StringSwitch<std::string>(type)
    .EndsWith("Decl *", "cast_or_null<" + std::string(type, 0, type.size()-1) +
              ">(GetDecl(Record[Idx++]))")
    .Case("QualType", "GetType(Record[Idx++])")
    .Default("Record[Idx++]");
}

// Assumes that the way to get the value is SA->getname()
std::string WritePCHRecord(StringRef type, StringRef name) {
  return StringSwitch<std::string>(type)
    .EndsWith("Decl *", "AddDeclRef(" + std::string(name) +
                        ", Record);\n")
    .Case("QualType", "AddTypeRef(" + std::string(name) + ", Record);\n")
    .Default("Record.push_back(" + std::string(name) + ");\n");
}

namespace {
  class Argument {
    std::string lowerName, upperName;
    StringRef attrName;

  public:
    Argument(Record &Arg, StringRef Attr)
      : lowerName(Arg.getValueAsString("Name")), upperName(lowerName),
        attrName(Attr) {
      if (!lowerName.empty()) {
        lowerName[0] = std::tolower(lowerName[0]);
        upperName[0] = std::toupper(upperName[0]);
      }
    }
    virtual ~Argument() {}

    StringRef getLowerName() const { return lowerName; }
    StringRef getUpperName() const { return upperName; }
    StringRef getAttrName() const { return attrName; }

    // These functions print the argument contents formatted in different ways.
    virtual void writeAccessors(raw_ostream &OS) const = 0;
    virtual void writeAccessorDefinitions(raw_ostream &OS) const {}
    virtual void writeCloneArgs(raw_ostream &OS) const = 0;
    virtual void writeCtorBody(raw_ostream &OS) const {}
    virtual void writeCtorInitializers(raw_ostream &OS) const = 0;
    virtual void writeCtorParameters(raw_ostream &OS) const = 0;
    virtual void writeDeclarations(raw_ostream &OS) const = 0;
    virtual void writePCHReadArgs(raw_ostream &OS) const = 0;
    virtual void writePCHReadDecls(raw_ostream &OS) const = 0;
    virtual void writePCHWrite(raw_ostream &OS) const = 0;
  };

  class SimpleArgument : public Argument {
    std::string type;

  public:
    SimpleArgument(Record &Arg, StringRef Attr, std::string T)
      : Argument(Arg, Attr), type(T)
    {}

    void writeAccessors(raw_ostream &OS) const {
      OS << "  " << type << " get" << getUpperName() << "() const {\n";
      OS << "    return " << getLowerName() << ";\n";
      OS << "  }";
    }
    void writeCloneArgs(raw_ostream &OS) const {
      OS << getLowerName();
    }
    void writeCtorInitializers(raw_ostream &OS) const {
      OS << getLowerName() << "(" << getUpperName() << ")";
    }
    void writeCtorParameters(raw_ostream &OS) const {
      OS << type << " " << getUpperName();
    }
    void writeDeclarations(raw_ostream &OS) const {
      OS << type << " " << getLowerName() << ";";
    }
    void writePCHReadDecls(raw_ostream &OS) const {
      std::string read = ReadPCHRecord(type);
      OS << "    " << type << " " << getLowerName() << " = " << read << ";\n";
    }
    void writePCHReadArgs(raw_ostream &OS) const {
      OS << getLowerName();
    }
    void writePCHWrite(raw_ostream &OS) const {
      OS << "    " << WritePCHRecord(type, "SA->get" +
                                           std::string(getUpperName()) + "()");
    }
  };

  class StringArgument : public Argument {
  public:
    StringArgument(Record &Arg, StringRef Attr)
      : Argument(Arg, Attr)
    {}

    void writeAccessors(raw_ostream &OS) const {
      OS << "  llvm::StringRef get" << getUpperName() << "() const {\n";
      OS << "    return llvm::StringRef(" << getLowerName() << ", "
         << getLowerName() << "Length);\n";
      OS << "  }\n";
      OS << "  unsigned get" << getUpperName() << "Length() const {\n";
      OS << "    return " << getLowerName() << "Length;\n";
      OS << "  }\n";
      OS << "  void set" << getUpperName()
         << "(ASTContext &C, llvm::StringRef S) {\n";
      OS << "    " << getLowerName() << "Length = S.size();\n";
      OS << "    this->" << getLowerName() << " = new (C, 1) char ["
         << getLowerName() << "Length];\n";
      OS << "    std::memcpy(this->" << getLowerName() << ", S.data(), "
         << getLowerName() << "Length);\n";
      OS << "  }";
    }
    void writeCloneArgs(raw_ostream &OS) const {
      OS << "get" << getUpperName() << "()";
    }
    void writeCtorBody(raw_ostream &OS) const {
      OS << "      std::memcpy(" << getLowerName() << ", " << getUpperName()
         << ".data(), " << getLowerName() << "Length);";
    }
    void writeCtorInitializers(raw_ostream &OS) const {
      OS << getLowerName() << "Length(" << getUpperName() << ".size()),"
         << getLowerName() << "(new (Ctx, 1) char[" << getLowerName()
         << "Length])";
    }
    void writeCtorParameters(raw_ostream &OS) const {
      OS << "llvm::StringRef " << getUpperName();
    }
    void writeDeclarations(raw_ostream &OS) const {
      OS << "unsigned " << getLowerName() << "Length;\n";
      OS << "char *" << getLowerName() << ";";
    }
    void writePCHReadDecls(raw_ostream &OS) const {
      OS << "    std::string " << getLowerName() << "= ReadString(Record, Idx);\n";
    }
    void writePCHReadArgs(raw_ostream &OS) const {
      OS << getLowerName();
    }
    void writePCHWrite(raw_ostream &OS) const {
      OS << "    AddString(SA->get" << getUpperName() << "(), Record);\n";
    }
  };

  class AlignedArgument : public Argument {
  public:
    AlignedArgument(Record &Arg, StringRef Attr)
      : Argument(Arg, Attr)
    {}

    void writeAccessors(raw_ostream &OS) const {
      OS << "  bool is" << getUpperName() << "Dependent() const;\n";

      OS << "  unsigned get" << getUpperName() << "(ASTContext &Ctx) const;\n";

      OS << "  bool is" << getUpperName() << "Expr() const {\n";
      OS << "    return is" << getLowerName() << "Expr;\n";
      OS << "  }\n";

      OS << "  Expr *get" << getUpperName() << "Expr() const {\n";
      OS << "    assert(is" << getLowerName() << "Expr);\n";
      OS << "    return " << getLowerName() << "Expr;\n";
      OS << "  }\n";

      OS << "  TypeSourceInfo *get" << getUpperName() << "Type() const {\n";
      OS << "    assert(!is" << getLowerName() << "Expr);\n";
      OS << "    return " << getLowerName() << "Type;\n";
      OS << "  }";
    }
    void writeAccessorDefinitions(raw_ostream &OS) const {
      OS << "bool " << getAttrName() << "Attr::is" << getUpperName()
         << "Dependent() const {\n";
      OS << "  if (is" << getLowerName() << "Expr)\n";
      OS << "    return " << getLowerName() << "Expr && (" << getLowerName()
         << "Expr->isValueDependent() || " << getLowerName()
         << "Expr->isTypeDependent());\n"; 
      OS << "  else\n";
      OS << "    return " << getLowerName()
         << "Type->getType()->isDependentType();\n";
      OS << "}\n";

      // FIXME: Do not do the calculation here
      // FIXME: Handle types correctly
      // A null pointer means maximum alignment
      // FIXME: Load the platform-specific maximum alignment, rather than
      //        16, the x86 max.
      OS << "unsigned " << getAttrName() << "Attr::get" << getUpperName()
         << "(ASTContext &Ctx) const {\n";
      OS << "  assert(!is" << getUpperName() << "Dependent());\n";
      OS << "  if (is" << getLowerName() << "Expr)\n";
      OS << "    return (" << getLowerName() << "Expr ? " << getLowerName()
         << "Expr->EvaluateAsInt(Ctx).getZExtValue() : 16)"
         << "* Ctx.getCharWidth();\n";
      OS << "  else\n";
      OS << "    return 0; // FIXME\n";
      OS << "}\n";
    }
    void writeCloneArgs(raw_ostream &OS) const {
      OS << "is" << getLowerName() << "Expr, is" << getLowerName()
         << "Expr ? static_cast<void*>(" << getLowerName()
         << "Expr) : " << getLowerName()
         << "Type";
    }
    void writeCtorBody(raw_ostream &OS) const {
      OS << "    if (is" << getLowerName() << "Expr)\n";
      OS << "       " << getLowerName() << "Expr = reinterpret_cast<Expr *>("
         << getUpperName() << ");\n";
      OS << "    else\n";
      OS << "       " << getLowerName()
         << "Type = reinterpret_cast<TypeSourceInfo *>(" << getUpperName()
         << ");";
    }
    void writeCtorInitializers(raw_ostream &OS) const {
      OS << "is" << getLowerName() << "Expr(Is" << getUpperName() << "Expr)";
    }
    void writeCtorParameters(raw_ostream &OS) const {
      OS << "bool Is" << getUpperName() << "Expr, void *" << getUpperName();
    }
    void writeDeclarations(raw_ostream &OS) const {
      OS << "bool is" << getLowerName() << "Expr;\n";
      OS << "union {\n";
      OS << "Expr *" << getLowerName() << "Expr;\n";
      OS << "TypeSourceInfo *" << getLowerName() << "Type;\n";
      OS << "};";
    }
    void writePCHReadArgs(raw_ostream &OS) const {
      OS << "is" << getLowerName() << "Expr, " << getLowerName() << "Ptr";
    }
    void writePCHReadDecls(raw_ostream &OS) const {
      OS << "    bool is" << getLowerName() << "Expr = Record[Idx++];\n";
      OS << "    void *" << getLowerName() << "Ptr;\n";
      OS << "    if (is" << getLowerName() << "Expr)\n";
      OS << "      " << getLowerName() << "Ptr = ReadExpr(DeclsCursor);\n";
      OS << "    else\n";
      OS << "      " << getLowerName()
         << "Ptr = GetTypeSourceInfo(DeclsCursor, Record, Idx);\n";
    }
    void writePCHWrite(raw_ostream &OS) const {
      OS << "    Record.push_back(SA->is" << getUpperName() << "Expr());\n";
      OS << "    if (SA->is" << getUpperName() << "Expr())\n";
      OS << "      AddStmt(SA->get" << getUpperName() << "Expr());\n";
      OS << "    else\n";
      OS << "      AddTypeSourceInfo(SA->get" << getUpperName()
         << "Type(), Record);\n";
    }
  };

  class VariadicArgument : public Argument {
    std::string type;

  public:
    VariadicArgument(Record &Arg, StringRef Attr, std::string T)
      : Argument(Arg, Attr), type(T)
    {}

    std::string getType() const { return type; }

    void writeAccessors(raw_ostream &OS) const {
      OS << "  typedef " << type << "* " << getLowerName() << "_iterator;\n";
      OS << "  " << getLowerName() << "_iterator " << getLowerName()
         << "_begin() const {\n";
      OS << "    return " << getLowerName() << ";\n";
      OS << "  }\n";
      OS << "  " << getLowerName() << "_iterator " << getLowerName()
         << "_end() const {\n";
      OS << "    return " << getLowerName() << " + " << getLowerName()
         << "Size;\n";
      OS << "  }\n";
      OS << "  unsigned " << getLowerName() << "_size() const {\n"
         << "    return " << getLowerName() << "Size;\n;";
      OS << "  }";
    }
    void writeCloneArgs(raw_ostream &OS) const {
      OS << getLowerName() << ", " << getLowerName() << "Size";
    }
    void writeCtorBody(raw_ostream &OS) const {
      // FIXME: memcpy is not safe on non-trivial types.
      OS << "    std::memcpy(" << getLowerName() << ", " << getUpperName()
         << ", " << getLowerName() << "Size * sizeof(" << getType() << "));\n";
    }
    void writeCtorInitializers(raw_ostream &OS) const {
      OS << getLowerName() << "Size(" << getUpperName() << "Size), "
         << getLowerName() << "(new (Ctx, 16) " << getType() << "["
         << getLowerName() << "Size])";
    }
    void writeCtorParameters(raw_ostream &OS) const {
      OS << getType() << " *" << getUpperName() << ", unsigned "
         << getUpperName() << "Size";
    }
    void writeDeclarations(raw_ostream &OS) const {
      OS << "  unsigned " << getLowerName() << "Size;\n";
      OS << "  " << getType() << " *" << getLowerName() << ";";
    }
    void writePCHReadDecls(raw_ostream &OS) const {
      OS << "  unsigned " << getLowerName() << "Size = Record[Idx++];\n";
      OS << "  llvm::SmallVector<" << type << ", 4> " << getLowerName()
         << ";\n";
      OS << "  " << getLowerName() << ".reserve(" << getLowerName()
         << "Size);\n";
      OS << "  for (unsigned i = " << getLowerName() << "Size; i; --i)\n";
      
      std::string read = ReadPCHRecord(type);
      OS << "    " << getLowerName() << ".push_back(" << read << ");\n";
    }
    void writePCHReadArgs(raw_ostream &OS) const {
      OS << getLowerName() << ".data(), " << getLowerName() << "Size";
    }
    void writePCHWrite(raw_ostream &OS) const{
      OS << "    Record.push_back(SA->" << getLowerName() << "_size());\n";
      OS << "    for (" << getAttrName() << "Attr::" << getLowerName()
         << "_iterator i = SA->" << getLowerName() << "_begin(), e = SA->"
         << getLowerName() << "_end(); i != e; ++i)\n";
      OS << "      " << WritePCHRecord(type, "(*i)");
    }
  };

  class EnumArgument : public Argument {
    std::string type;
    std::vector<StringRef> values, enums;
  public:
    EnumArgument(Record &Arg, StringRef Attr)
      : Argument(Arg, Attr), type(Arg.getValueAsString("Type")),
        values(getValueAsListOfStrings(Arg, "Values")),
        enums(getValueAsListOfStrings(Arg, "Enums"))
    {}

    void writeAccessors(raw_ostream &OS) const {
      OS << "  " << type << " get" << getUpperName() << "() const {\n";
      OS << "    return " << getLowerName() << ";\n";
      OS << "  }";
    }
    void writeCloneArgs(raw_ostream &OS) const {
      OS << getLowerName();
    }
    void writeCtorInitializers(raw_ostream &OS) const {
      OS << getLowerName() << "(" << getUpperName() << ")";
    }
    void writeCtorParameters(raw_ostream &OS) const {
      OS << type << " " << getUpperName();
    }
    void writeDeclarations(raw_ostream &OS) const {
      // Calculate the various enum values
      std::vector<StringRef> uniques(enums);
      std::sort(uniques.begin(), uniques.end());
      uniques.erase(std::unique(uniques.begin(), uniques.end()),
                    uniques.end());
      // FIXME: Emit a proper error
      assert(!uniques.empty());

      std::vector<StringRef>::iterator i = uniques.begin(),
                                       e = uniques.end();
      // The last one needs to not have a comma.
      --e;

      OS << "public:\n";
      OS << "  enum " << type << " {\n";
      for (; i != e; ++i)
        OS << "    " << *i << ",\n";
      OS << "    " << *e << "\n";
      OS << "  };\n";
      OS << "private:\n";
      OS << "  " << type << " " << getLowerName() << ";";
    }
    void writePCHReadDecls(raw_ostream &OS) const {
      OS << "    " << getAttrName() << "Attr::" << type << " " << getLowerName()
         << "(static_cast<" << getAttrName() << "Attr::" << type
         << ">(Record[Idx++]));\n";
    }
    void writePCHReadArgs(raw_ostream &OS) const {
      OS << getLowerName();
    }
    void writePCHWrite(raw_ostream &OS) const {
      OS << "Record.push_back(SA->get" << getUpperName() << "());\n";
    }
  };
}

static Argument *createArgument(Record &Arg, StringRef Attr,
                                Record *Search = 0) {
  if (!Search)
    Search = &Arg;

  Argument *Ptr = 0;
  llvm::StringRef ArgName = Search->getName();

  if (ArgName == "AlignedArgument") Ptr = new AlignedArgument(Arg, Attr);
  else if (ArgName == "EnumArgument") Ptr = new EnumArgument(Arg, Attr);
  else if (ArgName == "ExprArgument") Ptr = new SimpleArgument(Arg, Attr,
                                                               "Expr *");
  else if (ArgName == "FunctionArgument")
    Ptr = new SimpleArgument(Arg, Attr, "FunctionDecl *");
  else if (ArgName == "IdentifierArgument")
    Ptr = new SimpleArgument(Arg, Attr, "IdentifierInfo *");
  else if (ArgName == "IntArgument") Ptr = new SimpleArgument(Arg, Attr, "int");
  else if (ArgName == "StringArgument") Ptr = new StringArgument(Arg, Attr);
  else if (ArgName == "TypeArgument")
    Ptr = new SimpleArgument(Arg, Attr, "QualType");
  else if (ArgName == "UnsignedArgument")
    Ptr = new SimpleArgument(Arg, Attr, "unsigned");
  else if (ArgName == "VariadicUnsignedArgument")
    Ptr = new VariadicArgument(Arg, Attr, "unsigned");

  if (!Ptr) {
    std::vector<Record*> Bases = Search->getSuperClasses();
    for (std::vector<Record*>::iterator i = Bases.begin(), e = Bases.end();
         i != e; ++i) {
      Ptr = createArgument(Arg, Attr, *i);
      if (Ptr)
        break;
    }
  }
  return Ptr;
}

void ClangAttrClassEmitter::run(raw_ostream &OS) {
  OS << "// This file is generated by TableGen. Do not edit.\n\n";
  OS << "#ifndef LLVM_CLANG_ATTR_CLASSES_INC\n";
  OS << "#define LLVM_CLANG_ATTR_CLASSES_INC\n\n";

  std::vector<Record*> Attrs = Records.getAllDerivedDefinitions("Attr");

  for (std::vector<Record*>::iterator i = Attrs.begin(), e = Attrs.end();
       i != e; ++i) {
    Record &R = **i;

    OS << "class " << R.getName() << "Attr : public Attr {\n";

    std::vector<Record*> ArgRecords = R.getValueAsListOfDefs("Args");
    std::vector<Argument*> Args;
    std::vector<Argument*>::iterator ai, ae;
    Args.reserve(ArgRecords.size());

    for (std::vector<Record*>::iterator ri = ArgRecords.begin(),
                                        re = ArgRecords.end();
         ri != re; ++ri) {
      Record &ArgRecord = **ri;
      Argument *Arg = createArgument(ArgRecord, R.getName());
      assert(Arg);
      Args.push_back(Arg);

      Arg->writeDeclarations(OS);
      OS << "\n\n";
    }

    ae = Args.end();

    OS << "\n public:\n";
    OS << "  " << R.getName() << "Attr(SourceLocation L, ASTContext &Ctx\n";
    
    for (ai = Args.begin(); ai != ae; ++ai) {
      OS << "              , ";
      (*ai)->writeCtorParameters(OS);
      OS << "\n";
    }
    
    OS << "             )\n";
    OS << "    : Attr(attr::" << R.getName() << ", L)\n";

    for (ai = Args.begin(); ai != ae; ++ai) {
      OS << "              , ";
      (*ai)->writeCtorInitializers(OS);
      OS << "\n";
    }

    OS << "  {\n";
  
    for (ai = Args.begin(); ai != ae; ++ai) {
      (*ai)->writeCtorBody(OS);
      OS << "\n";
    }
    OS << "  }\n\n";

    OS << "  virtual " << R.getName() << "Attr *clone (ASTContext &C) const;\n";

    for (ai = Args.begin(); ai != ae; ++ai) {
      (*ai)->writeAccessors(OS);
      OS << "\n\n";
    }

    OS << R.getValueAsCode("AdditionalMembers");
    OS << "\n\n";

    OS << "  static bool classof(const Attr *A) { return A->getKind() == "
       << "attr::" << R.getName() << "; }\n";
    OS << "  static bool classof(const " << R.getName()
       << "Attr *) { return true; }\n";
    OS << "};\n\n";
  }

  OS << "#endif\n";
}

void ClangAttrImplEmitter::run(raw_ostream &OS) {
  OS << "// This file is generated by TableGen. Do not edit.\n\n";

  std::vector<Record*> Attrs = Records.getAllDerivedDefinitions("Attr");
  std::vector<Record*>::iterator i = Attrs.begin(), e = Attrs.end(), ri, re;
  std::vector<Argument*>::iterator ai, ae;

  for (; i != e; ++i) {
    Record &R = **i;
    std::vector<Record*> ArgRecords = R.getValueAsListOfDefs("Args");
    std::vector<Argument*> Args;
    for (ri = ArgRecords.begin(), re = ArgRecords.end(); ri != re; ++ri)
      Args.push_back(createArgument(**ri, R.getName()));

    for (ai = Args.begin(), ae = Args.end(); ai != ae; ++ai)
      (*ai)->writeAccessorDefinitions(OS);

    OS << R.getName() << "Attr *" << R.getName()
       << "Attr::clone(ASTContext &C) const {\n";
    OS << "  return new (C) " << R.getName() << "Attr(getLocation(), C";
    for (ai = Args.begin(); ai != ae; ++ai) {
      OS << ", ";
      (*ai)->writeCloneArgs(OS);
    }
    OS << ");\n}\n\n";
  }
}

void ClangAttrListEmitter::run(raw_ostream &OS) {
  OS << "// This file is generated by TableGen. Do not edit.\n\n";

  OS << "#ifndef LAST_ATTR\n";
  OS << "#define LAST_ATTR(NAME) ATTR(NAME)\n";
  OS << "#endif\n\n";
   
  std::vector<Record*> Attrs = Records.getAllDerivedDefinitions("Attr");
  std::vector<Record*>::iterator i = Attrs.begin(), e = Attrs.end();

  if (i != e) {
    // Move the end iterator back to emit the last attribute.
    for(--e; i != e; ++i)
      OS << "ATTR(" << (*i)->getName() << ")\n";
    
    OS << "LAST_ATTR(" << (*i)->getName() << ")\n\n";
  }

  OS << "#undef LAST_ATTR\n";
  OS << "#undef ATTR\n";
}

void ClangAttrPCHReadEmitter::run(raw_ostream &OS) {
  OS << "// This file is generated by TableGen. Do not edit.\n\n";

  std::vector<Record*> Attrs = Records.getAllDerivedDefinitions("Attr"),
                       ArgRecords;
  std::vector<Record*>::iterator i = Attrs.begin(), e = Attrs.end(), ai, ae;
  std::vector<Argument*> Args;
  std::vector<Argument*>::iterator ri, re;

  OS << "  switch (Kind) {\n";
  OS << "  default:\n";
  OS << "    assert(0 && \"Unknown attribute!\");\n";
  OS << "    break;\n";
  for (; i != e; ++i) {
    Record &R = **i;
    OS << "  case attr::" << R.getName() << ": {\n";
    ArgRecords = R.getValueAsListOfDefs("Args");
    Args.clear();
    for (ai = ArgRecords.begin(), ae = ArgRecords.end(); ai != ae; ++ai) {
      Argument *A = createArgument(**ai, R.getName());
      Args.push_back(A);
      A->writePCHReadDecls(OS);
    }
    OS << "    New = new (*Context) " << R.getName() << "Attr(Loc, *Context";
    for (ri = Args.begin(), re = Args.end(); ri != re; ++ri) {
      OS << ", ";
      (*ri)->writePCHReadArgs(OS);
    }
    OS << ");\n";
    OS << "    break;\n";
    OS << "  }\n";
  }
  OS << "  }\n";
}

void ClangAttrPCHWriteEmitter::run(raw_ostream &OS) {
  std::vector<Record*> Attrs = Records.getAllDerivedDefinitions("Attr"), Args;
  std::vector<Record*>::iterator i = Attrs.begin(), e = Attrs.end(), ai, ae;

  OS << "  switch (A->getKind()) {\n";
  OS << "  default:\n";
  OS << "    llvm_unreachable(\"Unknown attribute kind!\");\n";
  OS << "    break;\n";
  for (; i != e; ++i) {
    Record &R = **i;
    OS << "  case attr::" << R.getName() << ": {\n";
    Args = R.getValueAsListOfDefs("Args");
    if (!Args.empty())
      OS << "    const " << R.getName() << "Attr *SA = cast<" << R.getName()
         << "Attr>(A);\n";
    for (ai = Args.begin(), ae = Args.end(); ai != ae; ++ai)
      createArgument(**ai, R.getName())->writePCHWrite(OS);
    OS << "    break;\n";
    OS << "  }\n";
  }
  OS << "  }\n";
}