lib/CodeGen/IntrinsicLowering.cpp

   1 //===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the default intrinsic lowering implementation.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/CodeGen/IntrinsicLowering.h"
  15 #include "llvm/Constants.h"
  16 #include "llvm/DerivedTypes.h"
  17 #include "llvm/Module.h"
  18 #include "llvm/Instructions.h"
  19 #include "llvm/Type.h"
  20 #include <iostream>
  21
  22 using namespace llvm;
  23
  24 template <class ArgIt>
  25 static Function *EnsureFunctionExists(Module &M, const char *Name,
  26                                       ArgIt ArgBegin, ArgIt ArgEnd,
  27                                       const Type *RetTy) {
  28   if (Function *F = M.getNamedFunction(Name)) return F;
  29   // It doesn't already exist in the program, insert a new definition now.
  30   std::vector<const Type *> ParamTys;
  31   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  32     ParamTys.push_back(I->getType());
  33   return M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
  34 }
  35
  36 /// ReplaceCallWith - This function is used when we want to lower an intrinsic
  37 /// call to a call of an external function.  This handles hard cases such as
  38 /// when there was already a prototype for the external function, and if that
  39 /// prototype doesn't match the arguments we expect to pass in.
  40 template <class ArgIt>
  41 static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
  42                                  ArgIt ArgBegin, ArgIt ArgEnd,
  43                                  const Type *RetTy, Function *&FCache) {
  44   if (!FCache) {
  45     // If we haven't already looked up this function, check to see if the
  46     // program already contains a function with this name.
  47     Module *M = CI->getParent()->getParent()->getParent();
  48     FCache = M->getNamedFunction(NewFn);
  49     if (!FCache) {
  50       // It doesn't already exist in the program, insert a new definition now.
  51       std::vector<const Type *> ParamTys;
  52       for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  53         ParamTys.push_back((*I)->getType());
  54       FCache = M->getOrInsertFunction(NewFn,
  55                                      FunctionType::get(RetTy, ParamTys, false));
  56     }
  57    }
  58
  59   const FunctionType *FT = FCache->getFunctionType();
  60   std::vector<Value*> Operands;
  61   unsigned ArgNo = 0;
  62   for (ArgIt I = ArgBegin; I != ArgEnd && ArgNo != FT->getNumParams();
  63        ++I, ++ArgNo) {
  64     Value *Arg = *I;
  65     if (Arg->getType() != FT->getParamType(ArgNo))
  66       Arg = new CastInst(Arg, FT->getParamType(ArgNo), Arg->getName(), CI);
  67     Operands.push_back(Arg);
  68   }
  69   // Pass nulls into any additional arguments...
  70   for (; ArgNo != FT->getNumParams(); ++ArgNo)
  71     Operands.push_back(Constant::getNullValue(FT->getParamType(ArgNo)));
  72
  73   std::string Name = CI->getName(); CI->setName("");
  74   if (FT->getReturnType() == Type::VoidTy) Name.clear();
  75   CallInst *NewCI = new CallInst(FCache, Operands, Name, CI);
  76   if (!CI->use_empty()) {
  77     Value *V = NewCI;
  78     if (CI->getType() != NewCI->getType())
  79       V = new CastInst(NewCI, CI->getType(), Name, CI);
  80     CI->replaceAllUsesWith(V);
  81   }
  82   return NewCI;
  83 }
  84
  85 void DefaultIntrinsicLowering::AddPrototypes(Module &M) {
  86   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
  87     if (I->isExternal() && !I->use_empty())
  88       switch (I->getIntrinsicID()) {
  89       default: break;
  90       case Intrinsic::setjmp:
  91         EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
  92                              Type::IntTy);
  93         break;
  94       case Intrinsic::longjmp:
  95         EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
  96                              Type::VoidTy);
  97         break;
  98       case Intrinsic::siglongjmp:
  99         EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(),
 100                              Type::VoidTy);
 101         break;
 102       case Intrinsic::memcpy_i32:
 103       case Intrinsic::memcpy_i64:
 104         EnsureFunctionExists(M, "memcpy", I->arg_begin(), --I->arg_end(),
 105                              I->arg_begin()->getType());
 106         break;
 107       case Intrinsic::memmove_i32:
 108       case Intrinsic::memmove_i64:
 109         EnsureFunctionExists(M, "memmove", I->arg_begin(), --I->arg_end(),
 110                              I->arg_begin()->getType());
 111         break;
 112       case Intrinsic::memset_i32:
 113       case Intrinsic::memset_i64:
 114         M.getOrInsertFunction("memset", PointerType::get(Type::SByteTy),
 115                               PointerType::get(Type::SByteTy),
 116                               Type::IntTy, (--(--I->arg_end()))->getType(),
 117                               (Type *)0);
 118         break;
 119       case Intrinsic::isunordered_f32:
 120       case Intrinsic::isunordered_f64:
 121         EnsureFunctionExists(M, "isunordered", I->arg_begin(), I->arg_end(),
 122                              Type::BoolTy);
 123         break;
 124       case Intrinsic::sqrt_f32:
 125       case Intrinsic::sqrt_f64:
 126         if(I->arg_begin()->getType() == Type::FloatTy)
 127           EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(),
 128                                Type::FloatTy);
 129         else
 130           EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(),
 131                                Type::DoubleTy);
 132         break;
 133       }
 134 }
 135
 136 /// LowerBSWAP - Emit the code to lower bswap of V before the specified
 137 /// instruction IP.
 138 static Value *LowerBSWAP(Value *V, Instruction *IP) {
 139   assert(V->getType()->isInteger() && "Can't bswap a non-integer type!");
 140
 141   const Type *DestTy = V->getType();
 142
 143   // Force to unsigned so that the shift rights are logical.
 144   if (DestTy->isSigned())
 145     V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);
 146
 147   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 148
 149   switch(BitSize) {
 150   default: assert(0 && "Unhandled type size of value to byteswap!");
 151   case 16: {
 152     Value *Tmp1 = new ShiftInst(Instruction::Shl, V,
 153                                 ConstantInt::get(Type::UByteTy,8),"bswap.2",IP);
 154     Value *Tmp2 = new ShiftInst(Instruction::Shr, V,
 155                                 ConstantInt::get(Type::UByteTy,8),"bswap.1",IP);
 156     V = BinaryOperator::createOr(Tmp1, Tmp2, "bswap.i16", IP);
 157     break;
 158   }
 159   case 32: {
 160     Value *Tmp4 = new ShiftInst(Instruction::Shl, V,
 161                               ConstantInt::get(Type::UByteTy,24),"bswap.4", IP);
 162     Value *Tmp3 = new ShiftInst(Instruction::Shl, V,
 163                                 ConstantInt::get(Type::UByteTy,8),"bswap.3",IP);
 164     Value *Tmp2 = new ShiftInst(Instruction::Shr, V,
 165                                 ConstantInt::get(Type::UByteTy,8),"bswap.2",IP);
 166     Value *Tmp1 = new ShiftInst(Instruction::Shr, V,
 167                               ConstantInt::get(Type::UByteTy,24),"bswap.1", IP);
 168     Tmp3 = BinaryOperator::createAnd(Tmp3,
 169                                      ConstantUInt::get(Type::UIntTy, 0xFF0000),
 170                                      "bswap.and3", IP);
 171     Tmp2 = BinaryOperator::createAnd(Tmp2,
 172                                      ConstantUInt::get(Type::UIntTy, 0xFF00),
 173                                      "bswap.and2", IP);
 174     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or1", IP);
 175     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or2", IP);
 176     V = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.i32", IP);
 177     break;
 178   }
 179   case 64: {
 180     Value *Tmp8 = new ShiftInst(Instruction::Shl, V,
 181                               ConstantInt::get(Type::UByteTy,56),"bswap.8", IP);
 182     Value *Tmp7 = new ShiftInst(Instruction::Shl, V,
 183                               ConstantInt::get(Type::UByteTy,40),"bswap.7", IP);
 184     Value *Tmp6 = new ShiftInst(Instruction::Shl, V,
 185                               ConstantInt::get(Type::UByteTy,24),"bswap.6", IP);
 186     Value *Tmp5 = new ShiftInst(Instruction::Shl, V,
 187                                 ConstantInt::get(Type::UByteTy,8),"bswap.5",IP);
 188     Value *Tmp4 = new ShiftInst(Instruction::Shr, V,
 189                                 ConstantInt::get(Type::UByteTy,8),"bswap.4",IP);
 190     Value *Tmp3 = new ShiftInst(Instruction::Shr, V,
 191                               ConstantInt::get(Type::UByteTy,24),"bswap.3", IP);
 192     Value *Tmp2 = new ShiftInst(Instruction::Shr, V,
 193                               ConstantInt::get(Type::UByteTy,40),"bswap.2", IP);
 194     Value *Tmp1 = new ShiftInst(Instruction::Shr, V,
 195                               ConstantInt::get(Type::UByteTy,56),"bswap.1", IP);
 196     Tmp7 = BinaryOperator::createAnd(Tmp7,
 197                           ConstantUInt::get(Type::ULongTy, 0xFF000000000000ULL),
 198                           "bswap.and7", IP);
 199     Tmp6 = BinaryOperator::createAnd(Tmp6,
 200                             ConstantUInt::get(Type::ULongTy, 0xFF0000000000ULL),
 201                             "bswap.and6", IP);
 202     Tmp5 = BinaryOperator::createAnd(Tmp5,
 203                               ConstantUInt::get(Type::ULongTy, 0xFF00000000ULL),
 204                               "bswap.and5", IP);
 205     Tmp4 = BinaryOperator::createAnd(Tmp4,
 206                                 ConstantUInt::get(Type::ULongTy, 0xFF000000ULL),
 207                                 "bswap.and4", IP);
 208     Tmp3 = BinaryOperator::createAnd(Tmp3,
 209                                   ConstantUInt::get(Type::ULongTy, 0xFF0000ULL),
 210                                   "bswap.and3", IP);
 211     Tmp2 = BinaryOperator::createAnd(Tmp2,
 212                                     ConstantUInt::get(Type::ULongTy, 0xFF00ULL),
 213                                     "bswap.and2", IP);
 214     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp7, "bswap.or1", IP);
 215     Tmp6 = BinaryOperator::createOr(Tmp6, Tmp5, "bswap.or2", IP);
 216     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or3", IP);
 217     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or4", IP);
 218     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp6, "bswap.or5", IP);
 219     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp2, "bswap.or6", IP);
 220     V = BinaryOperator::createOr(Tmp8, Tmp4, "bswap.i64", IP);
 221     break;
 222   }
 223   }
 224
 225   if (V->getType() != DestTy)
 226     V = new CastInst(V, DestTy, V->getName(), IP);
 227   return V;
 228 }
 229
 230 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified
 231 /// instruction IP.
 232 static Value *LowerCTPOP(Value *V, Instruction *IP) {
 233   assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!");
 234
 235   static const uint64_t MaskValues[6] = {
 236     0x5555555555555555ULL, 0x3333333333333333ULL,
 237     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
 238     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
 239   };
 240
 241   const Type *DestTy = V->getType();
 242
 243   // Force to unsigned so that the shift rights are logical.
 244   if (DestTy->isSigned())
 245     V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);
 246
 247   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 248   for (unsigned i = 1, ct = 0; i != BitSize; i <<= 1, ++ct) {
 249     Value *MaskCst =
 250       ConstantExpr::getCast(ConstantUInt::get(Type::ULongTy,
 251                                               MaskValues[ct]), V->getType());
 252     Value *LHS = BinaryOperator::createAnd(V, MaskCst, "cppop.and1", IP);
 253     Value *VShift = new ShiftInst(Instruction::Shr, V,
 254                       ConstantInt::get(Type::UByteTy, i), "ctpop.sh", IP);
 255     Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP);
 256     V = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP);
 257   }
 258
 259   if (V->getType() != DestTy)
 260     V = new CastInst(V, DestTy, V->getName(), IP);
 261   return V;
 262 }
 263
 264 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified
 265 /// instruction IP.
 266 static Value *LowerCTLZ(Value *V, Instruction *IP) {
 267   const Type *DestTy = V->getType();
 268
 269   // Force to unsigned so that the shift rights are logical.
 270   if (DestTy->isSigned())
 271     V = new CastInst(V, DestTy->getUnsignedVersion(), V->getName(), IP);
 272
 273   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 274   for (unsigned i = 1; i != BitSize; i <<= 1) {
 275     Value *ShVal = ConstantInt::get(Type::UByteTy, i);
 276     ShVal = new ShiftInst(Instruction::Shr, V, ShVal, "ctlz.sh", IP);
 277     V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP);
 278   }
 279
 280   if (V->getType() != DestTy)
 281     V = new CastInst(V, DestTy, V->getName(), IP);
 282
 283   V = BinaryOperator::createNot(V, "", IP);
 284   return LowerCTPOP(V, IP);
 285 }
 286
 287
 288
 289 void DefaultIntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
 290   Function *Callee = CI->getCalledFunction();
 291   assert(Callee && "Cannot lower an indirect call!");
 292
 293   switch (Callee->getIntrinsicID()) {
 294   case Intrinsic::not_intrinsic:
 295     std::cerr << "Cannot lower a call to a non-intrinsic function '"
 296               << Callee->getName() << "'!\n";
 297     abort();
 298   default:
 299     std::cerr << "Error: Code generator does not support intrinsic function '"
 300               << Callee->getName() << "'!\n";
 301     abort();
 302
 303     // The setjmp/longjmp intrinsics should only exist in the code if it was
 304     // never optimized (ie, right out of the CFE), or if it has been hacked on
 305     // by the lowerinvoke pass.  In both cases, the right thing to do is to
 306     // convert the call to an explicit setjmp or longjmp call.
 307   case Intrinsic::setjmp: {
 308     static Function *SetjmpFCache = 0;
 309     Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(),
 310                                Type::IntTy, SetjmpFCache);
 311     if (CI->getType() != Type::VoidTy)
 312       CI->replaceAllUsesWith(V);
 313     break;
 314   }
 315   case Intrinsic::sigsetjmp:
 316      if (CI->getType() != Type::VoidTy)
 317        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 318      break;
 319
 320   case Intrinsic::longjmp: {
 321     static Function *LongjmpFCache = 0;
 322     ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(),
 323                     Type::VoidTy, LongjmpFCache);
 324     break;
 325   }
 326
 327   case Intrinsic::siglongjmp: {
 328     // Insert the call to abort
 329     static Function *AbortFCache = 0;
 330     ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(), Type::VoidTy,
 331                     AbortFCache);
 332     break;
 333   }
 334   case Intrinsic::ctpop_i8:
 335   case Intrinsic::ctpop_i16:
 336   case Intrinsic::ctpop_i32:
 337   case Intrinsic::ctpop_i64:
 338     CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI));
 339     break;
 340
 341   case Intrinsic::bswap_i16:
 342   case Intrinsic::bswap_i32:
 343   case Intrinsic::bswap_i64:
 344     CI->replaceAllUsesWith(LowerBSWAP(CI->getOperand(1), CI));
 345     break;
 346
 347   case Intrinsic::ctlz_i8:
 348   case Intrinsic::ctlz_i16:
 349   case Intrinsic::ctlz_i32:
 350   case Intrinsic::ctlz_i64:
 351     CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI));
 352     break;
 353
 354   case Intrinsic::cttz_i8:
 355   case Intrinsic::cttz_i16:
 356   case Intrinsic::cttz_i32:
 357   case Intrinsic::cttz_i64: {
 358     // cttz(x) -> ctpop(~X & (X-1))
 359     Value *Src = CI->getOperand(1);
 360     Value *NotSrc = BinaryOperator::createNot(Src, Src->getName()+".not", CI);
 361     Value *SrcM1  = ConstantInt::get(Src->getType(), 1);
 362     SrcM1 = BinaryOperator::createSub(Src, SrcM1, "", CI);
 363     Src = LowerCTPOP(BinaryOperator::createAnd(NotSrc, SrcM1, "", CI), CI);
 364     CI->replaceAllUsesWith(Src);
 365     break;
 366   }
 367
 368   case Intrinsic::stacksave:
 369   case Intrinsic::stackrestore: {
 370     static bool Warned = false;
 371     if (!Warned)
 372       std::cerr << "WARNING: this target does not support the llvm.stack"
 373        << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
 374            "save" : "restore") << " intrinsic.\n";
 375     Warned = true;
 376     if (Callee->getIntrinsicID() == Intrinsic::stacksave)
 377       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 378     break;
 379   }
 380
 381   case Intrinsic::returnaddress:
 382   case Intrinsic::frameaddress:
 383     std::cerr << "WARNING: this target does not support the llvm."
 384               << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
 385                   "return" : "frame") << "address intrinsic.\n";
 386     CI->replaceAllUsesWith(ConstantPointerNull::get(
 387                                             cast<PointerType>(CI->getType())));
 388     break;
 389
 390   case Intrinsic::prefetch:
 391     break;    // Simply strip out prefetches on unsupported architectures
 392
 393   case Intrinsic::pcmarker:
 394     break;    // Simply strip out pcmarker on unsupported architectures
 395   case Intrinsic::readcyclecounter: {
 396     std::cerr << "WARNING: this target does not support the llvm.readcyclecoun"
 397               << "ter intrinsic.  It is being lowered to a constant 0\n";
 398     CI->replaceAllUsesWith(ConstantUInt::get(Type::ULongTy, 0));
 399     break;
 400   }
 401
 402   case Intrinsic::dbg_stoppoint:
 403   case Intrinsic::dbg_region_start:
 404   case Intrinsic::dbg_region_end:
 405   case Intrinsic::dbg_declare:
 406   case Intrinsic::dbg_func_start:
 407     if (CI->getType() != Type::VoidTy)
 408       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 409     break;    // Simply strip out debugging intrinsics
 410
 411   case Intrinsic::memcpy_i32:
 412   case Intrinsic::memcpy_i64: {
 413     // The memcpy intrinsic take an extra alignment argument that the memcpy
 414     // libc function does not.
 415     static Function *MemcpyFCache = 0;
 416     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 417                     (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 418     break;
 419   }
 420   case Intrinsic::memmove_i32:
 421   case Intrinsic::memmove_i64: {
 422     // The memmove intrinsic take an extra alignment argument that the memmove
 423     // libc function does not.
 424     static Function *MemmoveFCache = 0;
 425     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 426                     (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 427     break;
 428   }
 429   case Intrinsic::memset_i32:
 430   case Intrinsic::memset_i64: {
 431     // The memset intrinsic take an extra alignment argument that the memset
 432     // libc function does not.
 433     static Function *MemsetFCache = 0;
 434     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
 435                     (*(CI->op_begin()+1))->getType(), MemsetFCache);
 436     break;
 437   }
 438   case Intrinsic::isunordered_f32:
 439   case Intrinsic::isunordered_f64: {
 440     Value *L = CI->getOperand(1);
 441     Value *R = CI->getOperand(2);
 442
 443     Value *LIsNan = new SetCondInst(Instruction::SetNE, L, L, "LIsNan", CI);
 444     Value *RIsNan = new SetCondInst(Instruction::SetNE, R, R, "RIsNan", CI);
 445     CI->replaceAllUsesWith(
 446       BinaryOperator::create(Instruction::Or, LIsNan, RIsNan,
 447                              "isunordered", CI));
 448     break;
 449   }
 450   case Intrinsic::sqrt_f32:
 451   case Intrinsic::sqrt_f64: {
 452     static Function *sqrtFCache = 0;
 453     static Function *sqrtfFCache = 0;
 454     if(CI->getType() == Type::FloatTy)
 455       ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(),
 456                       Type::FloatTy, sqrtfFCache);
 457     else
 458       ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(),
 459                       Type::DoubleTy, sqrtFCache);
 460     break;
 461   }
 462   }
 463
 464   assert(CI->use_empty() &&
 465          "Lowering should have eliminated any uses of the intrinsic call!");
 466   CI->eraseFromParent();
 467 }