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 IntrinsicLowering class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Constants.h"
  15 #include "llvm/DerivedTypes.h"
  16 #include "llvm/Module.h"
  17 #include "llvm/Instructions.h"
  18 #include "llvm/Type.h"
  19 #include "llvm/CodeGen/IntrinsicLowering.h"
  20 #include "llvm/Support/Streams.h"
  21 using namespace llvm;
  22
  23 template <class ArgIt>
  24 static void EnsureFunctionExists(Module &M, const char *Name,
  25                                  ArgIt ArgBegin, ArgIt ArgEnd,
  26                                  const Type *RetTy) {
  27   // Insert a correctly-typed definition now.
  28   std::vector<const Type *> ParamTys;
  29   for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  30     ParamTys.push_back(I->getType());
  31   M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
  32 }
  33
  34 /// ReplaceCallWith - This function is used when we want to lower an intrinsic
  35 /// call to a call of an external function.  This handles hard cases such as
  36 /// when there was already a prototype for the external function, and if that
  37 /// prototype doesn't match the arguments we expect to pass in.
  38 template <class ArgIt>
  39 static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
  40                                  ArgIt ArgBegin, ArgIt ArgEnd,
  41                                  const Type *RetTy, Constant *&FCache) {
  42   if (!FCache) {
  43     // If we haven't already looked up this function, check to see if the
  44     // program already contains a function with this name.
  45     Module *M = CI->getParent()->getParent()->getParent();
  46     // Get or insert the definition now.
  47     std::vector<const Type *> ParamTys;
  48     for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
  49       ParamTys.push_back((*I)->getType());
  50     FCache = M->getOrInsertFunction(NewFn,
  51                                     FunctionType::get(RetTy, ParamTys, false));
  52   }
  53
  54   std::vector<Value*> Operands(ArgBegin, ArgEnd);
  55   CallInst *NewCI = new CallInst(FCache, Operands, CI->getName(), CI);
  56   if (!CI->use_empty())
  57     CI->replaceAllUsesWith(NewCI);
  58   return NewCI;
  59 }
  60
  61 void IntrinsicLowering::AddPrototypes(Module &M) {
  62   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
  63     if (I->isExternal() && !I->use_empty())
  64       switch (I->getIntrinsicID()) {
  65       default: break;
  66       case Intrinsic::setjmp:
  67         EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
  68                              Type::Int32Ty);
  69         break;
  70       case Intrinsic::longjmp:
  71         EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
  72                              Type::VoidTy);
  73         break;
  74       case Intrinsic::siglongjmp:
  75         EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(),
  76                              Type::VoidTy);
  77         break;
  78       case Intrinsic::memcpy_i32:
  79       case Intrinsic::memcpy_i64:
  80         EnsureFunctionExists(M, "memcpy", I->arg_begin(), --I->arg_end(),
  81                              I->arg_begin()->getType());
  82         break;
  83       case Intrinsic::memmove_i32:
  84       case Intrinsic::memmove_i64:
  85         EnsureFunctionExists(M, "memmove", I->arg_begin(), --I->arg_end(),
  86                              I->arg_begin()->getType());
  87         break;
  88       case Intrinsic::memset_i32:
  89       case Intrinsic::memset_i64:
  90         M.getOrInsertFunction("memset", PointerType::get(Type::Int8Ty),
  91                               PointerType::get(Type::Int8Ty),
  92                               Type::Int32Ty, (--(--I->arg_end()))->getType(),
  93                               (Type *)0);
  94         break;
  95       case Intrinsic::sqrt_f32:
  96       case Intrinsic::sqrt_f64:
  97         if(I->arg_begin()->getType() == Type::FloatTy)
  98           EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(),
  99                                Type::FloatTy);
 100         else
 101           EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(),
 102                                Type::DoubleTy);
 103         break;
 104       }
 105 }
 106
 107 /// LowerBSWAP - Emit the code to lower bswap of V before the specified
 108 /// instruction IP.
 109 static Value *LowerBSWAP(Value *V, Instruction *IP) {
 110   assert(V->getType()->isInteger() && "Can't bswap a non-integer type!");
 111
 112   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 113
 114   switch(BitSize) {
 115   default: assert(0 && "Unhandled type size of value to byteswap!");
 116   case 16: {
 117     Value *Tmp1 = new ShiftInst(Instruction::Shl, V,
 118                                 ConstantInt::get(Type::Int8Ty,8),"bswap.2",IP);
 119     Value *Tmp2 = new ShiftInst(Instruction::LShr, V,
 120                                 ConstantInt::get(Type::Int8Ty,8),"bswap.1",IP);
 121     V = BinaryOperator::createOr(Tmp1, Tmp2, "bswap.i16", IP);
 122     break;
 123   }
 124   case 32: {
 125     Value *Tmp4 = new ShiftInst(Instruction::Shl, V,
 126                               ConstantInt::get(Type::Int8Ty,24),"bswap.4", IP);
 127     Value *Tmp3 = new ShiftInst(Instruction::Shl, V,
 128                               ConstantInt::get(Type::Int8Ty,8),"bswap.3",IP);
 129     Value *Tmp2 = new ShiftInst(Instruction::LShr, V,
 130                               ConstantInt::get(Type::Int8Ty,8),"bswap.2",IP);
 131     Value *Tmp1 = new ShiftInst(Instruction::LShr, V,
 132                               ConstantInt::get(Type::Int8Ty,24),"bswap.1", IP);
 133     Tmp3 = BinaryOperator::createAnd(Tmp3,
 134                                      ConstantInt::get(Type::Int32Ty, 0xFF0000),
 135                                      "bswap.and3", IP);
 136     Tmp2 = BinaryOperator::createAnd(Tmp2,
 137                                      ConstantInt::get(Type::Int32Ty, 0xFF00),
 138                                      "bswap.and2", IP);
 139     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or1", IP);
 140     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or2", IP);
 141     V = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.i32", IP);
 142     break;
 143   }
 144   case 64: {
 145     Value *Tmp8 = new ShiftInst(Instruction::Shl, V,
 146                               ConstantInt::get(Type::Int8Ty,56),"bswap.8", IP);
 147     Value *Tmp7 = new ShiftInst(Instruction::Shl, V,
 148                               ConstantInt::get(Type::Int8Ty,40),"bswap.7", IP);
 149     Value *Tmp6 = new ShiftInst(Instruction::Shl, V,
 150                               ConstantInt::get(Type::Int8Ty,24),"bswap.6", IP);
 151     Value *Tmp5 = new ShiftInst(Instruction::Shl, V,
 152                               ConstantInt::get(Type::Int8Ty,8),"bswap.5", IP);
 153     Value* Tmp4 = new ShiftInst(Instruction::LShr, V,
 154                               ConstantInt::get(Type::Int8Ty,8),"bswap.4", IP);
 155     Value* Tmp3 = new ShiftInst(Instruction::LShr, V,
 156                               ConstantInt::get(Type::Int8Ty,24),"bswap.3", IP);
 157     Value* Tmp2 = new ShiftInst(Instruction::LShr, V,
 158                               ConstantInt::get(Type::Int8Ty,40),"bswap.2", IP);
 159     Value* Tmp1 = new ShiftInst(Instruction::LShr, V,
 160                               ConstantInt::get(Type::Int8Ty,56),"bswap.1", IP);
 161     Tmp7 = BinaryOperator::createAnd(Tmp7,
 162                              ConstantInt::get(Type::Int64Ty,
 163                                0xFF000000000000ULL),
 164                              "bswap.and7", IP);
 165     Tmp6 = BinaryOperator::createAnd(Tmp6,
 166                              ConstantInt::get(Type::Int64Ty, 0xFF0000000000ULL),
 167                              "bswap.and6", IP);
 168     Tmp5 = BinaryOperator::createAnd(Tmp5,
 169                              ConstantInt::get(Type::Int64Ty, 0xFF00000000ULL),
 170                              "bswap.and5", IP);
 171     Tmp4 = BinaryOperator::createAnd(Tmp4,
 172                              ConstantInt::get(Type::Int64Ty, 0xFF000000ULL),
 173                              "bswap.and4", IP);
 174     Tmp3 = BinaryOperator::createAnd(Tmp3,
 175                              ConstantInt::get(Type::Int64Ty, 0xFF0000ULL),
 176                              "bswap.and3", IP);
 177     Tmp2 = BinaryOperator::createAnd(Tmp2,
 178                              ConstantInt::get(Type::Int64Ty, 0xFF00ULL),
 179                              "bswap.and2", IP);
 180     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp7, "bswap.or1", IP);
 181     Tmp6 = BinaryOperator::createOr(Tmp6, Tmp5, "bswap.or2", IP);
 182     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or3", IP);
 183     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or4", IP);
 184     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp6, "bswap.or5", IP);
 185     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp2, "bswap.or6", IP);
 186     V = BinaryOperator::createOr(Tmp8, Tmp4, "bswap.i64", IP);
 187     break;
 188   }
 189   }
 190   return V;
 191 }
 192
 193 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified
 194 /// instruction IP.
 195 static Value *LowerCTPOP(Value *V, Instruction *IP) {
 196   assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!");
 197
 198   static const uint64_t MaskValues[6] = {
 199     0x5555555555555555ULL, 0x3333333333333333ULL,
 200     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
 201     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
 202   };
 203
 204   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 205
 206   for (unsigned i = 1, ct = 0; i != BitSize; i <<= 1, ++ct) {
 207     Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]);
 208     Value *LHS = BinaryOperator::createAnd(V, MaskCst, "cppop.and1", IP);
 209     Value *VShift = new ShiftInst(Instruction::LShr, V,
 210                       ConstantInt::get(Type::Int8Ty, i), "ctpop.sh", IP);
 211     Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP);
 212     V = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP);
 213   }
 214
 215   return V;
 216 }
 217
 218 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified
 219 /// instruction IP.
 220 static Value *LowerCTLZ(Value *V, Instruction *IP) {
 221
 222   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 223   for (unsigned i = 1; i != BitSize; i <<= 1) {
 224     Value *ShVal = ConstantInt::get(Type::Int8Ty, i);
 225     ShVal = new ShiftInst(Instruction::LShr, V, ShVal, "ctlz.sh", IP);
 226     V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP);
 227   }
 228
 229   V = BinaryOperator::createNot(V, "", IP);
 230   return LowerCTPOP(V, IP);
 231 }
 232
 233
 234
 235 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
 236   Function *Callee = CI->getCalledFunction();
 237   assert(Callee && "Cannot lower an indirect call!");
 238
 239   switch (Callee->getIntrinsicID()) {
 240   case Intrinsic::not_intrinsic:
 241     cerr << "Cannot lower a call to a non-intrinsic function '"
 242          << Callee->getName() << "'!\n";
 243     abort();
 244   default:
 245     cerr << "Error: Code generator does not support intrinsic function '"
 246          << Callee->getName() << "'!\n";
 247     abort();
 248
 249     // The setjmp/longjmp intrinsics should only exist in the code if it was
 250     // never optimized (ie, right out of the CFE), or if it has been hacked on
 251     // by the lowerinvoke pass.  In both cases, the right thing to do is to
 252     // convert the call to an explicit setjmp or longjmp call.
 253   case Intrinsic::setjmp: {
 254     static Constant *SetjmpFCache = 0;
 255     Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(),
 256                                Type::Int32Ty, SetjmpFCache);
 257     if (CI->getType() != Type::VoidTy)
 258       CI->replaceAllUsesWith(V);
 259     break;
 260   }
 261   case Intrinsic::sigsetjmp:
 262      if (CI->getType() != Type::VoidTy)
 263        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 264      break;
 265
 266   case Intrinsic::longjmp: {
 267     static Constant *LongjmpFCache = 0;
 268     ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(),
 269                     Type::VoidTy, LongjmpFCache);
 270     break;
 271   }
 272
 273   case Intrinsic::siglongjmp: {
 274     // Insert the call to abort
 275     static Constant *AbortFCache = 0;
 276     ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(),
 277                     Type::VoidTy, AbortFCache);
 278     break;
 279   }
 280   case Intrinsic::ctpop_i8:
 281   case Intrinsic::ctpop_i16:
 282   case Intrinsic::ctpop_i32:
 283   case Intrinsic::ctpop_i64:
 284     CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI));
 285     break;
 286
 287   case Intrinsic::bswap_i16:
 288   case Intrinsic::bswap_i32:
 289   case Intrinsic::bswap_i64:
 290     CI->replaceAllUsesWith(LowerBSWAP(CI->getOperand(1), CI));
 291     break;
 292
 293   case Intrinsic::ctlz_i8:
 294   case Intrinsic::ctlz_i16:
 295   case Intrinsic::ctlz_i32:
 296   case Intrinsic::ctlz_i64:
 297     CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI));
 298     break;
 299
 300   case Intrinsic::cttz_i8:
 301   case Intrinsic::cttz_i16:
 302   case Intrinsic::cttz_i32:
 303   case Intrinsic::cttz_i64: {
 304     // cttz(x) -> ctpop(~X & (X-1))
 305     Value *Src = CI->getOperand(1);
 306     Value *NotSrc = BinaryOperator::createNot(Src, Src->getName()+".not", CI);
 307     Value *SrcM1  = ConstantInt::get(Src->getType(), 1);
 308     SrcM1 = BinaryOperator::createSub(Src, SrcM1, "", CI);
 309     Src = LowerCTPOP(BinaryOperator::createAnd(NotSrc, SrcM1, "", CI), CI);
 310     CI->replaceAllUsesWith(Src);
 311     break;
 312   }
 313
 314   case Intrinsic::stacksave:
 315   case Intrinsic::stackrestore: {
 316     static bool Warned = false;
 317     if (!Warned)
 318       cerr << "WARNING: this target does not support the llvm.stack"
 319            << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
 320                "save" : "restore") << " intrinsic.\n";
 321     Warned = true;
 322     if (Callee->getIntrinsicID() == Intrinsic::stacksave)
 323       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 324     break;
 325   }
 326
 327   case Intrinsic::returnaddress:
 328   case Intrinsic::frameaddress:
 329     cerr << "WARNING: this target does not support the llvm."
 330          << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
 331              "return" : "frame") << "address intrinsic.\n";
 332     CI->replaceAllUsesWith(ConstantPointerNull::get(
 333                                             cast<PointerType>(CI->getType())));
 334     break;
 335
 336   case Intrinsic::prefetch:
 337     break;    // Simply strip out prefetches on unsupported architectures
 338
 339   case Intrinsic::pcmarker:
 340     break;    // Simply strip out pcmarker on unsupported architectures
 341   case Intrinsic::readcyclecounter: {
 342     cerr << "WARNING: this target does not support the llvm.readcyclecoun"
 343          << "ter intrinsic.  It is being lowered to a constant 0\n";
 344     CI->replaceAllUsesWith(ConstantInt::get(Type::Int64Ty, 0));
 345     break;
 346   }
 347
 348   case Intrinsic::dbg_stoppoint:
 349   case Intrinsic::dbg_region_start:
 350   case Intrinsic::dbg_region_end:
 351   case Intrinsic::dbg_func_start:
 352   case Intrinsic::dbg_declare:
 353     break;    // Simply strip out debugging intrinsics
 354
 355   case Intrinsic::memcpy_i32: {
 356     static Constant *MemcpyFCache = 0;
 357     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 358                     (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 359     break;
 360   }
 361   case Intrinsic::memcpy_i64: {
 362     static Constant *MemcpyFCache = 0;
 363     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 364                      (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 365     break;
 366   }
 367   case Intrinsic::memmove_i32: {
 368     static Constant *MemmoveFCache = 0;
 369     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 370                     (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 371     break;
 372   }
 373   case Intrinsic::memmove_i64: {
 374     static Constant *MemmoveFCache = 0;
 375     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 376                     (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 377     break;
 378   }
 379   case Intrinsic::memset_i32: {
 380     static Constant *MemsetFCache = 0;
 381     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
 382                     (*(CI->op_begin()+1))->getType(), MemsetFCache);
 383   }
 384   case Intrinsic::memset_i64: {
 385     static Constant *MemsetFCache = 0;
 386     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
 387                     (*(CI->op_begin()+1))->getType(), MemsetFCache);
 388     break;
 389   }
 390   case Intrinsic::sqrt_f32: {
 391     static Constant *sqrtfFCache = 0;
 392     ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(),
 393                     Type::FloatTy, sqrtfFCache);
 394     break;
 395   }
 396   case Intrinsic::sqrt_f64: {
 397     static Constant *sqrtFCache = 0;
 398     ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(),
 399                     Type::DoubleTy, sqrtFCache);
 400     break;
 401   }
 402   }
 403
 404   assert(CI->use_empty() &&
 405          "Lowering should have eliminated any uses of the intrinsic call!");
 406   CI->eraseFromParent();
 407 }