utils/TableGen/NeonEmitter.cpp

//===- NeonEmitter.cpp - Generate arm_neon.h for use with clang -*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend is responsible for emitting arm_neon.h, which includes
// a declaration and definition of each function specified by the ARM NEON 
// compiler interface.  See ARM document DUI0348B.
//
// Each NEON instruction is implemented in terms of 1 or more functions which
// are suffixed with the element type of the input vectors.  Functions may be 
// implemented in terms of generic vector operations such as +, *, -, etc. or
// by calling a __builtin_-prefixed function which will be handled by clang's
// CodeGen library.
//
// Additional validation code can be generated by this file when runHeader() is
// called, rather than the normal run() entry point.
//
//===----------------------------------------------------------------------===//

#include "NeonEmitter.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include <string>

using namespace llvm;

/// ParseTypes - break down a string such as "fQf" into a vector of StringRefs,
/// which each StringRef representing a single type declared in the string.
/// for "fQf" we would end up with 2 StringRefs, "f", and "Qf", representing
/// 2xfloat and 4xfloat respectively.
static void ParseTypes(Record *r, std::string &s,
                       SmallVectorImpl<StringRef> &TV) {
  const char *data = s.data();
  int len = 0;
  
  for (unsigned i = 0, e = s.size(); i != e; ++i, ++len) {
    if (data[len] == 'P' || data[len] == 'Q' || data[len] == 'U')
      continue;
    
    switch (data[len]) {
      case 'c':
      case 's':
      case 'i':
      case 'l':
      case 'h':
      case 'f':
        break;
      default:
        throw TGError(r->getLoc(),
                      "Unexpected letter: " + std::string(data + len, 1));
        break;
    }
    TV.push_back(StringRef(data, len + 1));
    data += len + 1;
    len = -1;
  }
}

/// Widen - Convert a type code into the next wider type.  char -> short,
/// short -> int, etc.
static char Widen(const char t) {
  switch (t) {
    case 'c':
      return 's';
    case 's':
      return 'i';
    case 'i':
      return 'l';
    default: throw "unhandled type in widen!";
  }
  return '\0';
}

/// Narrow - Convert a type code into the next smaller type.  short -> char,
/// float -> half float, etc.
static char Narrow(const char t) {
  switch (t) {
    case 's':
      return 'c';
    case 'i':
      return 's';
    case 'l':
      return 'i';
    case 'f':
      return 'h';
    default: throw "unhandled type in widen!";
  }
  return '\0';
}

/// For a particular StringRef, return the base type code, and whether it has
/// the quad-vector, polynomial, or unsigned modifiers set.
static char ClassifyType(StringRef ty, bool &quad, bool &poly, bool &usgn) {
  unsigned off = 0;
  
  // remember quad.
  if (ty[off] == 'Q') {
    quad = true;
    ++off;
  }
  
  // remember poly.
  if (ty[off] == 'P') {
    poly = true;
    ++off;
  }
  
  // remember unsigned.
  if (ty[off] == 'U') {
    usgn = true;
    ++off;
  }
  
  // base type to get the type string for.
  return ty[off];
}

/// ModType - Transform a type code and its modifiers based on a mod code. The
/// mod code definitions may be found at the top of arm_neon.td.
static char ModType(const char mod, char type, bool &quad, bool &poly,
                    bool &usgn, bool &scal, bool &cnst, bool &pntr) {
  switch (mod) {
    case 't':
      if (poly) {
        poly = false;
        usgn = true;
      }
      break;
    case 'u':
      usgn = true;
    case 'x':
      poly = false;
      if (type == 'f')
        type = 'i';
      break;
    case 'f':
      if (type == 'h')
        quad = true;
      type = 'f';
      usgn = false;
      break;
    case 'g':
      quad = false;
      break;
    case 'w':
      type = Widen(type);
      quad = true;
      break;
    case 'n':
      type = Widen(type);
      break;
    case 'l':
      type = 'l';
      scal = true;
      usgn = true;
      break;
    case 's':
    case 'a':
      scal = true;
      break;
    case 'k':
      quad = true;
      break;
    case 'c':
      cnst = true;
    case 'p':
      pntr = true;
      scal = true;
      break;
    case 'h':
      type = Narrow(type);
      if (type == 'h')
        quad = false;
      break;
    case 'e':
      type = Narrow(type);
      usgn = true;
      break;
    default:
      break;
  }
  return type;
}

/// TypeString - for a modifier and type, generate the name of the typedef for
/// that type.  QUc -> uint8x8_t.
static std::string TypeString(const char mod, StringRef typestr) {
  bool quad = false;
  bool poly = false;
  bool usgn = false;
  bool scal = false;
  bool cnst = false;
  bool pntr = false;
  
  if (mod == 'v')
    return "void";
  if (mod == 'i')
    return "int";
  
  // base type to get the type string for.
  char type = ClassifyType(typestr, quad, poly, usgn);
  
  // Based on the modifying character, change the type and width if necessary.
  type = ModType(mod, type, quad, poly, usgn, scal, cnst, pntr);
  
  SmallString<128> s;
  
  if (usgn)
    s.push_back('u');
  
  switch (type) {
    case 'c':
      s += poly ? "poly8" : "int8";
      if (scal)
        break;
      s += quad ? "x16" : "x8";
      break;
    case 's':
      s += poly ? "poly16" : "int16";
      if (scal)
        break;
      s += quad ? "x8" : "x4";
      break;
    case 'i':
      s += "int32";
      if (scal)
        break;
      s += quad ? "x4" : "x2";
      break;
    case 'l':
      s += "int64";
      if (scal)
        break;
      s += quad ? "x2" : "x1";
      break;
    case 'h':
      s += "float16";
      if (scal)
        break;
      s += quad ? "x8" : "x4";
      break;
    case 'f':
      s += "float32";
      if (scal)
        break;
      s += quad ? "x4" : "x2";
      break;
    default:
      throw "unhandled type!";
      break;
  }

  if (mod == '2')
    s += "x2";
  if (mod == '3')
    s += "x3";
  if (mod == '4')
    s += "x4";
  
  // Append _t, finishing the type string typedef type.
  s += "_t";
  
  if (cnst)
    s += " const";
  
  if (pntr)
    s += " *";
  
  return s.str();
}

/// BuiltinTypeString - for a modifier and type, generate the clang
/// BuiltinsARM.def prototype code for the function.  See the top of clang's
/// Builtins.def for a description of the type strings.
static std::string BuiltinTypeString(const char mod, StringRef typestr,
                                     ClassKind ck, bool ret) {
  bool quad = false;
  bool poly = false;
  bool usgn = false;
  bool scal = false;
  bool cnst = false;
  bool pntr = false;
  
  if (mod == 'v')
    return "v";
  if (mod == 'i')
    return "i";
  
  // base type to get the type string for.
  char type = ClassifyType(typestr, quad, poly, usgn);
  
  // Based on the modifying character, change the type and width if necessary.
  type = ModType(mod, type, quad, poly, usgn, scal, cnst, pntr);

  if (pntr) {
    usgn = false;
    poly = false;
    type = 'v';
  }
  if (type == 'h') {
    type = 's';
    usgn = true;
  }
  usgn = usgn | poly | ((ck == ClassI || ck == ClassW) && scal && type != 'f');

  if (scal) {
    SmallString<128> s;

    if (usgn)
      s.push_back('U');
    
    if (type == 'l')
      s += "LLi";
    else
      s.push_back(type);
 
    if (cnst)
      s.push_back('C');
    if (pntr)
      s.push_back('*');
    return s.str();
  }

  // Since the return value must be one type, return a vector type of the
  // appropriate width which we will bitcast.  An exception is made for
  // returning structs of 2, 3, or 4 vectors which are returned in a sret-like
  // fashion, storing them to a pointer arg.
  if (ret) {
    if (mod == '2' || mod == '3' || mod == '4')
      return "vv*";
    if (mod == 'f' || (ck != ClassB && type == 'f'))
      return quad ? "V4f" : "V2f";
    if (ck != ClassB && type == 's')
      return quad ? "V8s" : "V4s";
    if (ck != ClassB && type == 'i')
      return quad ? "V4i" : "V2i";
    if (ck != ClassB && type == 'l')
      return quad ? "V2LLi" : "V1LLi";
    
    return quad ? "V16c" : "V8c";
  }    

  // Non-return array types are passed as individual vectors.
  if (mod == '2')
    return quad ? "V16cV16c" : "V8cV8c";
  if (mod == '3')
    return quad ? "V16cV16cV16c" : "V8cV8cV8c";
  if (mod == '4')
    return quad ? "V16cV16cV16cV16c" : "V8cV8cV8cV8c";

  if (mod == 'f' || (ck != ClassB && type == 'f'))
    return quad ? "V4f" : "V2f";
  if (ck != ClassB && type == 's')
    return quad ? "V8s" : "V4s";
  if (ck != ClassB && type == 'i')
    return quad ? "V4i" : "V2i";
  if (ck != ClassB && type == 'l')
    return quad ? "V2LLi" : "V1LLi";
  
  return quad ? "V16c" : "V8c";
}

/// MangleName - Append a type or width suffix to a base neon function name, 
/// and insert a 'q' in the appropriate location if the operation works on
/// 128b rather than 64b.   E.g. turn "vst2_lane" into "vst2q_lane_f32", etc.
static std::string MangleName(const std::string &name, StringRef typestr,
                              ClassKind ck) {
  if (name == "vcvt_f32_f16")
    return name;
  
  bool quad = false;
  bool poly = false;
  bool usgn = false;
  char type = ClassifyType(typestr, quad, poly, usgn);

  std::string s = name;
  
  switch (type) {
  case 'c':
    switch (ck) {
    case ClassS: s += poly ? "_p8" : usgn ? "_u8" : "_s8"; break;
    case ClassI: s += "_i8"; break;
    case ClassW: s += "_8"; break;
    default: break;
    }
    break;
  case 's':
    switch (ck) {
    case ClassS: s += poly ? "_p16" : usgn ? "_u16" : "_s16"; break;
    case ClassI: s += "_i16"; break;
    case ClassW: s += "_16"; break;
    default: break;
    }
    break;
  case 'i':
    switch (ck) {
    case ClassS: s += usgn ? "_u32" : "_s32"; break;
    case ClassI: s += "_i32"; break;
    case ClassW: s += "_32"; break;
    default: break;
    }
    break;
  case 'l':
    switch (ck) {
    case ClassS: s += usgn ? "_u64" : "_s64"; break;
    case ClassI: s += "_i64"; break;
    case ClassW: s += "_64"; break;
    default: break;
    }
    break;
  case 'h':
    switch (ck) {
    case ClassS:
    case ClassI: s += "_f16"; break;
    case ClassW: s += "_16"; break;
    default: break;
    }
    break;
  case 'f':
    switch (ck) {
    case ClassS:
    case ClassI: s += "_f32"; break;
    case ClassW: s += "_32"; break;
    default: break;
    }
    break;
  default:
    throw "unhandled type!";
    break;
  }
  if (ck == ClassB)
    s += "_v";
    
  // Insert a 'q' before the first '_' character so that it ends up before 
  // _lane or _n on vector-scalar operations.
  if (quad) {
    size_t pos = s.find('_');
    s = s.insert(pos, "q");
  }
  return s;
}

// Generate the string "(argtype a, argtype b, ...)"
static std::string GenArgs(const std::string &proto, StringRef typestr) {
  bool define = proto.find('i') != std::string::npos;
  char arg = 'a';
  
  std::string s;
  s += "(";
  
  for (unsigned i = 1, e = proto.size(); i != e; ++i, ++arg) {
    if (!define) {
      s += TypeString(proto[i], typestr);
      s.push_back(' ');
    }
    s.push_back(arg);
    if ((i + 1) < e)
      s += ", ";
  }
  
  s += ")";
  return s;
}

static std::string Duplicate(unsigned nElts, StringRef typestr, 
                             const std::string &a) {
  std::string s;
  
  s = "(" + TypeString('d', typestr) + "){ ";
  for (unsigned i = 0; i != nElts; ++i) {
    s += a;
    if ((i + 1) < nElts)
      s += ", ";
  }
  s += " }";
  
  return s;
}

// Generate the definition for this intrinsic, e.g. "a + b" for OpAdd.
static std::string GenOpString(OpKind op, const std::string &proto,
                               StringRef typestr) {
  bool dummy, quad = false;
  char type = ClassifyType(typestr, quad, dummy, dummy);
  unsigned nElts = 0;
  switch (type) {
    case 'c': nElts = 8; break;
    case 's': nElts = 4; break;
    case 'i': nElts = 2; break;
    case 'l': nElts = 1; break;
    case 'h': nElts = 4; break;
    case 'f': nElts = 2; break;
  }
  
  std::string ts = TypeString(proto[0], typestr);
  std::string s;
  if (op == OpHi || op == OpLo) {
    s = "union { " + ts + " r; double d; } u; u.d";
  } else {
    s = ts + " r; r";
  }
  
  s += " = ";

  switch(op) {
  case OpAdd:
    s += "a + b";
    break;
  case OpSub:
    s += "a - b";
    break;
  case OpMulN:
    s += "a * " + Duplicate(nElts << (int)quad, typestr, "b");
    break;
  case OpMul:
    s += "a * b";
    break;
  case OpMlaN:
    s += "a + (b * " + Duplicate(nElts << (int)quad, typestr, "c") + ")";
    break;
  case OpMla:
    s += "a + (b * c)";
    break;
  case OpMlsN:
    s += "a - (b * " + Duplicate(nElts << (int)quad, typestr, "c") + ")";
    break;
  case OpMls:
    s += "a - (b * c)";
    break;
  case OpEq:
    s += "(" + ts + ")(a == b)";
    break;
  case OpGe:
    s += "(" + ts + ")(a >= b)";
    break;
  case OpLe:
    s += "(" + ts + ")(a <= b)";
    break;
  case OpGt:
    s += "(" + ts + ")(a > b)";
    break;
  case OpLt:
    s += "(" + ts + ")(a < b)";
    break;
  case OpNeg:
    s += " -a";
    break;
  case OpNot:
    s += " ~a";
    break;
  case OpAnd:
    s += "a & b";
    break;
  case OpOr:
    s += "a | b";
    break;
  case OpXor:
    s += "a ^ b";
    break;
  case OpAndNot:
    s += "a & ~b";
    break;
  case OpOrNot:
    s += "a | ~b";
    break;
  case OpCast:
    s += "(" + ts + ")a";
    break;
  case OpConcat:
    s += "__builtin_shufflevector((int64x1_t)a";
    s += ", (int64x1_t)b, 0, 1)";
    break;
  case OpHi:
    s += "(((float64x2_t)a)[1])";
    break;
  case OpLo:
    s += "(((float64x2_t)a)[0])";
    break;
  case OpDup:
    s += Duplicate(nElts << (int)quad, typestr, "a");
    break;
  case OpSelect:
    // ((0 & 1) | (~0 & 2))
    ts = TypeString(proto[1], typestr);
    s += "(a & (" + ts + ")b) | ";
    s += "(~a & (" + ts + ")c)";
    break;
  case OpRev16:
    s += "__builtin_shufflevector(a, a";
    for (unsigned i = 2; i <= nElts << (int)quad; i += 2)
      for (unsigned j = 0; j != 2; ++j)
        s += ", " + utostr(i - j - 1);
    s += ")";
    break;
  case OpRev32:
    nElts >>= 1;
    s += "__builtin_shufflevector(a, a";
    for (unsigned i = nElts; i <= nElts << (1 + (int)quad); i += nElts)
      for (unsigned j = 0; j != nElts; ++j)
        s += ", " + utostr(i - j - 1);
    s += ")";
    break;
  case OpRev64:
    s += "__builtin_shufflevector(a, a";
    for (unsigned i = nElts; i <= nElts << (int)quad; i += nElts)
      for (unsigned j = 0; j != nElts; ++j)
        s += ", " + utostr(i - j - 1);
    s += ")";
    break;
  default:
    throw "unknown OpKind!";
    break;
  }
  if (op == OpHi || op == OpLo)
    s += "; return u.r;";
  else
    s += "; return r;";
  return s;
}

static unsigned GetNeonEnum(const std::string &proto, StringRef typestr) {
  unsigned mod = proto[0];
  unsigned ret = 0;

  if (mod == 'v' || mod == 'f')
    mod = proto[1];

  bool quad = false;
  bool poly = false;
  bool usgn = false;
  bool scal = false;
  bool cnst = false;
  bool pntr = false;
  
  // Base type to get the type string for.
  char type = ClassifyType(typestr, quad, poly, usgn);
  
  // Based on the modifying character, change the type and width if necessary.
  type = ModType(mod, type, quad, poly, usgn, scal, cnst, pntr);

  if (usgn)
    ret |= 0x08;
  if (quad && proto[1] != 'g')
    ret |= 0x10;
  
  switch (type) {
    case 'c': 
      ret |= poly ? 5 : 0;
      break;
    case 's':
      ret |= poly ? 6 : 1;
      break;
    case 'i':
      ret |= 2;
      break;
    case 'l':
      ret |= 3;
      break;
    case 'h':
      ret |= 7;
      break;
    case 'f':
      ret |= 4;
      break;
    default:
      throw "unhandled type!";
      break;
  }
  return ret;
}

// Generate the definition for this intrinsic, e.g. __builtin_neon_cls(a)
static std::string GenBuiltin(const std::string &name, const std::string &proto,
                              StringRef typestr, ClassKind ck) {
  bool dummy, quad = false;
  char type = ClassifyType(typestr, quad, dummy, dummy);
  unsigned nElts = 0;
  switch (type) {
    case 'c': nElts = 8; break;
    case 's': nElts = 4; break;
    case 'i': nElts = 2; break;
    case 'l': nElts = 1; break;
    case 'h': nElts = 4; break;
    case 'f': nElts = 2; break;
  }
  if (quad) nElts <<= 1;

  char arg = 'a';
  std::string s;

  // If this builtin returns a struct 2, 3, or 4 vectors, pass it as an implicit
  // sret-like argument.
  bool sret = (proto[0] == '2' || proto[0] == '3' || proto[0] == '4');

  // If this builtin takes an immediate argument, we need to #define it rather
  // than use a standard declaration, so that SemaChecking can range check
  // the immediate passed by the user.
  bool define = proto.find('i') != std::string::npos;

  // If all types are the same size, bitcasting the args will take care 
  // of arg checking.  The actual signedness etc. will be taken care of with
  // special enums.
  if (proto.find('s') == std::string::npos)
    ck = ClassB;

  if (proto[0] != 'v') {
    std::string ts = TypeString(proto[0], typestr);
    
    if (define) {
      if (sret)
        s += "({ " + ts + " r; ";
      else if (proto[0] != 's')
        s += "(" + ts + ")";
    } else if (sret) {
      s += ts + " r; ";
    } else {
      s += ts + " r; r = ";
    }
  }
  
  bool splat = proto.find('a') != std::string::npos;
  
  s += "__builtin_neon_";
  if (splat) {
    std::string vname(name, 0, name.size()-2);
    s += MangleName(vname, typestr, ck);
  } else {
    s += MangleName(name, typestr, ck);
  }
  s += "(";

  // Pass the address of the return variable as the first argument to sret-like
  // builtins.
  if (sret)
    s += "&r, ";
  
  for (unsigned i = 1, e = proto.size(); i != e; ++i, ++arg) {
    std::string args = std::string(&arg, 1);
    if (define)
      args = "(" + args + ")";
    
    // Handle multiple-vector values specially, emitting each subvector as an
    // argument to the __builtin.
    if (proto[i] == '2' || proto[i] == '3' || proto[i] == '4') {
      for (unsigned vi = 0, ve = proto[i] - '0'; vi != ve; ++vi) {
        s += args + ".val[" + utostr(vi) + "]";
        if ((vi + 1) < ve)
          s += ", ";
      }
      if ((i + 1) < e)
        s += ", ";

      continue;
    }
    
    if (splat && (i + 1) == e) 
      s += Duplicate(nElts, typestr, args);
    else
      s += args;
    if ((i + 1) < e)
      s += ", ";
  }
  
  // Extra constant integer to hold type class enum for this function, e.g. s8
  if (ck == ClassB)
    s += ", " + utostr(GetNeonEnum(proto, typestr));
  
  if (define)
    s += ")";
  else
    s += ");";

  if (proto[0] != 'v') {
    if (define) {
      if (sret)
        s += "; r; })";
    } else {
      s += " return r;";
    }
  }
  return s;
}

static std::string GenBuiltinDef(const std::string &name, 
                                 const std::string &proto,
                                 StringRef typestr, ClassKind ck) {
  std::string s("BUILTIN(__builtin_neon_");

  // If all types are the same size, bitcasting the args will take care 
  // of arg checking.  The actual signedness etc. will be taken care of with
  // special enums.
  if (proto.find('s') == std::string::npos)
    ck = ClassB;
  
  s += MangleName(name, typestr, ck);
  s += ", \"";
  
  for (unsigned i = 0, e = proto.size(); i != e; ++i)
    s += BuiltinTypeString(proto[i], typestr, ck, i == 0);

  // Extra constant integer to hold type class enum for this function, e.g. s8
  if (ck == ClassB)
    s += "i";
  
  s += "\", \"n\")";
  return s;
}

/// run - Read the records in arm_neon.td and output arm_neon.h.  arm_neon.h
/// is comprised of type definitions and function declarations.
void NeonEmitter::run(raw_ostream &OS) {
  EmitSourceFileHeader("ARM NEON Header", OS);
  
  // FIXME: emit license into file?
  
  OS << "#ifndef __ARM_NEON_H\n";
  OS << "#define __ARM_NEON_H\n\n";
  
  OS << "#ifndef __ARM_NEON__\n";
  OS << "#error \"NEON support not enabled\"\n";
  OS << "#endif\n\n";

  OS << "#include <stdint.h>\n\n";

  // Emit NEON-specific scalar typedefs.
  OS << "typedef float float32_t;\n";
  OS << "typedef uint8_t poly8_t;\n";
  OS << "typedef uint16_t poly16_t;\n";
  OS << "typedef uint16_t float16_t;\n";

  // Emit Neon vector typedefs.
  std::string TypedefTypes("cQcsQsiQilQlUcQUcUsQUsUiQUiUlQUlhQhfQfPcQPcPsQPs");
  SmallVector<StringRef, 24> TDTypeVec;
  ParseTypes(0, TypedefTypes, TDTypeVec);

  // Emit vector typedefs.
  for (unsigned i = 0, e = TDTypeVec.size(); i != e; ++i) {
    bool dummy, quad = false;
    (void) ClassifyType(TDTypeVec[i], quad, dummy, dummy);
    OS << "typedef __attribute__(( __vector_size__(";
      
    OS << utostr(8*(quad ? 2 : 1)) << ") )) ";
    if (!quad)
      OS << " ";
      
    OS << TypeString('s', TDTypeVec[i]);
    OS << " " << TypeString('d', TDTypeVec[i]) << ";\n";
  }
  OS << "\n";
  OS << "typedef __attribute__(( __vector_size__(8) ))  "
    "double float64x1_t;\n";
  OS << "typedef __attribute__(( __vector_size__(16) )) "
    "double float64x2_t;\n";
  OS << "\n";

  // Emit struct typedefs.
  for (unsigned vi = 2; vi != 5; ++vi) {
    for (unsigned i = 0, e = TDTypeVec.size(); i != e; ++i) {
      std::string ts = TypeString('d', TDTypeVec[i]);
      std::string vs = TypeString('0' + vi, TDTypeVec[i]);
      OS << "typedef struct " << vs << " {\n";
      OS << "  " << ts << " val";
      OS << "[" << utostr(vi) << "]";
      OS << ";\n} ";
      OS << vs << ";\n\n";
    }
  }
  
  OS << "#define __ai static __attribute__((__always_inline__))\n\n";

  std::vector<Record*> RV = Records.getAllDerivedDefinitions("Inst");
  
  // Unique the return+pattern types, and assign them.
  for (unsigned i = 0, e = RV.size(); i != e; ++i) {
    Record *R = RV[i];
    std::string name = LowercaseString(R->getName());
    std::string Proto = R->getValueAsString("Prototype");
    std::string Types = R->getValueAsString("Types");
    
    SmallVector<StringRef, 16> TypeVec;
    ParseTypes(R, Types, TypeVec);
    
    OpKind k = OpMap[R->getValueAsDef("Operand")->getName()];
    
    bool define = Proto.find('i') != std::string::npos;
    
    for (unsigned ti = 0, te = TypeVec.size(); ti != te; ++ti) {
      assert(!Proto.empty() && "");
      
      // static always inline + return type
      if (define)
        OS << "#define";
      else
        OS << "__ai " << TypeString(Proto[0], TypeVec[ti]);
      
      // Function name with type suffix
      OS << " " << MangleName(name, TypeVec[ti], ClassS);
      
      // Function arguments
      OS << GenArgs(Proto, TypeVec[ti]);
      
      // Definition.
      if (define)
        OS << " ";
      else
        OS << " { ";
      
      if (k != OpNone) {
        OS << GenOpString(k, Proto, TypeVec[ti]);
      } else {
        if (R->getSuperClasses().size() < 2)
          throw TGError(R->getLoc(), "Builtin has no class kind");
        
        ClassKind ck = ClassMap[R->getSuperClasses()[1]];

        if (ck == ClassNone)
          throw TGError(R->getLoc(), "Builtin has no class kind");
        OS << GenBuiltin(name, Proto, TypeVec[ti], ck);
      }
      if (!define)
        OS << " }";
      OS << "\n";
    }
    OS << "\n";
  }
  OS << "#undef __ai\n\n";
  OS << "#endif /* __ARM_NEON_H */\n";
}

static unsigned RangeFromType(StringRef typestr) {
  // base type to get the type string for.
  bool quad = false, dummy = false;
  char type = ClassifyType(typestr, quad, dummy, dummy);
  
  switch (type) {
    case 'c':
      return (8 << (int)quad) - 1;
    case 'h':
    case 's':
      return (4 << (int)quad) - 1;
    case 'f':
    case 'i':
      return (2 << (int)quad) - 1;
    case 'l':
      return (1 << (int)quad) - 1;
    default:
      throw "unhandled type!";
      break;
  }
  assert(0 && "unreachable");
  return 0;
}

/// runHeader - Emit a file with sections defining:
/// 1. the NEON section of BuiltinsARM.def.
/// 2. the SemaChecking code for the type overload checking.
/// 3. the SemaChecking code for validation of intrinsic immedate arguments.
void NeonEmitter::runHeader(raw_ostream &OS) {
  std::vector<Record*> RV = Records.getAllDerivedDefinitions("Inst");

  StringMap<OpKind> EmittedMap;
  
  // Generate BuiltinsARM.def for NEON
  OS << "#ifdef GET_NEON_BUILTINS\n";
  for (unsigned i = 0, e = RV.size(); i != e; ++i) {
    Record *R = RV[i];
    OpKind k = OpMap[R->getValueAsDef("Operand")->getName()];
    if (k != OpNone)
      continue;

    std::string Proto = R->getValueAsString("Prototype");
    
    // Functions with 'a' (the splat code) in the type prototype should not get
    // their own builtin as they use the non-splat variant.
    if (Proto.find('a') != std::string::npos)
      continue;
    
    std::string Types = R->getValueAsString("Types");
    SmallVector<StringRef, 16> TypeVec;
    ParseTypes(R, Types, TypeVec);
    
    if (R->getSuperClasses().size() < 2)
      throw TGError(R->getLoc(), "Builtin has no class kind");
    
    std::string name = LowercaseString(R->getName());
    ClassKind ck = ClassMap[R->getSuperClasses()[1]];
    
    for (unsigned ti = 0, te = TypeVec.size(); ti != te; ++ti) {
      // Generate the BuiltinsARM.def declaration for this builtin, ensuring
      // that each unique BUILTIN() macro appears only once in the output
      // stream.
      std::string bd = GenBuiltinDef(name, Proto, TypeVec[ti], ck);
      if (EmittedMap.count(bd))
        continue;
      
      EmittedMap[bd] = OpNone;
      OS << bd << "\n";
    }
  }
  OS << "#endif\n\n";
  
  // Generate the overloaded type checking code for SemaChecking.cpp
  OS << "#ifdef GET_NEON_OVERLOAD_CHECK\n";
  for (unsigned i = 0, e = RV.size(); i != e; ++i) {
    Record *R = RV[i];
    OpKind k = OpMap[R->getValueAsDef("Operand")->getName()];
    if (k != OpNone)
      continue;
    
    std::string Proto = R->getValueAsString("Prototype");
    std::string Types = R->getValueAsString("Types");
    std::string name = LowercaseString(R->getName());
    
    // Functions with 'a' (the splat code) in the type prototype should not get
    // their own builtin as they use the non-splat variant.
    if (Proto.find('a') != std::string::npos)
      continue;
    
    // Functions which have a scalar argument cannot be overloaded, no need to
    // check them if we are emitting the type checking code.
    if (Proto.find('s') != std::string::npos)
      continue;
    
    SmallVector<StringRef, 16> TypeVec;
    ParseTypes(R, Types, TypeVec);
    
    if (R->getSuperClasses().size() < 2)
      throw TGError(R->getLoc(), "Builtin has no class kind");
    
    int si = -1, qi = -1;
    unsigned mask = 0, qmask = 0;
    for (unsigned ti = 0, te = TypeVec.size(); ti != te; ++ti) {
      // Generate the switch case(s) for this builtin for the type validation.
      bool quad = false, poly = false, usgn = false;
      (void) ClassifyType(TypeVec[ti], quad, poly, usgn);
      
      if (quad) {
        qi = ti;
        qmask |= 1 << GetNeonEnum(Proto, TypeVec[ti]);
      } else {
        si = ti;
        mask |= 1 << GetNeonEnum(Proto, TypeVec[ti]);
      }
    }
    if (mask)
      OS << "case ARM::BI__builtin_neon_" 
      << MangleName(name, TypeVec[si], ClassB)
      << ": mask = " << "0x" << utohexstr(mask) << "; break;\n";
    if (qmask)
      OS << "case ARM::BI__builtin_neon_" 
      << MangleName(name, TypeVec[qi], ClassB)
      << ": mask = " << "0x" << utohexstr(qmask) << "; break;\n";
  }
  OS << "#endif\n\n";
  
  // Generate the intrinsic range checking code for shift/lane immediates.
  OS << "#ifdef GET_NEON_IMMEDIATE_CHECK\n";
  for (unsigned i = 0, e = RV.size(); i != e; ++i) {
    Record *R = RV[i];
    
    OpKind k = OpMap[R->getValueAsDef("Operand")->getName()];
    if (k != OpNone)
      continue;
    
    std::string name = LowercaseString(R->getName());
    std::string Proto = R->getValueAsString("Prototype");
    std::string Types = R->getValueAsString("Types");
    
    // Functions with 'a' (the splat code) in the type prototype should not get
    // their own builtin as they use the non-splat variant.
    if (Proto.find('a') != std::string::npos)
      continue;
    
    // Functions which do not have an immediate do not need to have range
    // checking code emitted.
    if (Proto.find('i') == std::string::npos)
      continue;
    
    SmallVector<StringRef, 16> TypeVec;
    ParseTypes(R, Types, TypeVec);
    
    if (R->getSuperClasses().size() < 2)
      throw TGError(R->getLoc(), "Builtin has no class kind");
    
    ClassKind ck = ClassMap[R->getSuperClasses()[1]];
    
    for (unsigned ti = 0, te = TypeVec.size(); ti != te; ++ti) {
      std::string namestr, shiftstr, rangestr;
      
      // Builtins which are overloaded by type will need to have their upper
      // bound computed at Sema time based on the type constant.
      if (Proto.find('s') == std::string::npos) {
        ck = ClassB;
        if (R->getValueAsBit("isShift")) {
          shiftstr = ", true";
          
          // Right shifts have an 'r' in the name, left shifts do not.
          if (name.find('r') != std::string::npos)
            rangestr = "l = 1; ";
        }
        rangestr += "u = RFT(TV" + shiftstr + ")";
      } else {
        rangestr = "u = " + utostr(RangeFromType(TypeVec[ti]));
      }
      // Make sure cases appear only once by uniquing them in a string map.
      namestr = MangleName(name, TypeVec[ti], ck);
      if (EmittedMap.count(namestr))
        continue;
      EmittedMap[namestr] = OpNone;

      // Calculate the index of the immediate that should be range checked.
      unsigned immidx = 0;
      
      // Builtins that return a struct of multiple vectors have an extra
      // leading arg for the struct return.
      if (Proto[0] == '2' || Proto[0] == '3' || Proto[0] == '4')
        ++immidx;
      
      // Add one to the index for each argument until we reach the immediate 
      // to be checked.  Structs of vectors are passed as multiple arguments.
      for (unsigned ii = 1, ie = Proto.size(); ii != ie; ++ii) {
        switch (Proto[ii]) {
          default:  immidx += 1; break;
          case '2': immidx += 2; break;
          case '3': immidx += 3; break;
          case '4': immidx += 4; break;
          case 'i': ie = ii + 1; break;
        }
      }
      OS << "case ARM::BI__builtin_neon_"  << MangleName(name, TypeVec[ti], ck)
         << ": i = " << immidx << "; " << rangestr << "; break;\n";
    }
  }
  OS << "#endif\n\n";
}