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::isunordered_f32:
  96       case Intrinsic::isunordered_f64:
  97         EnsureFunctionExists(M, "isunordered", I->arg_begin(), I->arg_end(),
  98                              Type::BoolTy);
  99         break;
 100       case Intrinsic::sqrt_f32:
 101       case Intrinsic::sqrt_f64:
 102         if(I->arg_begin()->getType() == Type::FloatTy)
 103           EnsureFunctionExists(M, "sqrtf", I->arg_begin(), I->arg_end(),
 104                                Type::FloatTy);
 105         else
 106           EnsureFunctionExists(M, "sqrt", I->arg_begin(), I->arg_end(),
 107                                Type::DoubleTy);
 108         break;
 109       }
 110 }
 111
 112 /// LowerBSWAP - Emit the code to lower bswap of V before the specified
 113 /// instruction IP.
 114 static Value *LowerBSWAP(Value *V, Instruction *IP) {
 115   assert(V->getType()->isInteger() && "Can't bswap a non-integer type!");
 116
 117   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 118
 119   switch(BitSize) {
 120   default: assert(0 && "Unhandled type size of value to byteswap!");
 121   case 16: {
 122     Value *Tmp1 = new ShiftInst(Instruction::Shl, V,
 123                                 ConstantInt::get(Type::Int8Ty,8),"bswap.2",IP);
 124     Value *Tmp2 = new ShiftInst(Instruction::LShr, V,
 125                                 ConstantInt::get(Type::Int8Ty,8),"bswap.1",IP);
 126     V = BinaryOperator::createOr(Tmp1, Tmp2, "bswap.i16", IP);
 127     break;
 128   }
 129   case 32: {
 130     Value *Tmp4 = new ShiftInst(Instruction::Shl, V,
 131                               ConstantInt::get(Type::Int8Ty,24),"bswap.4", IP);
 132     Value *Tmp3 = new ShiftInst(Instruction::Shl, V,
 133                               ConstantInt::get(Type::Int8Ty,8),"bswap.3",IP);
 134     Value *Tmp2 = new ShiftInst(Instruction::LShr, V,
 135                               ConstantInt::get(Type::Int8Ty,8),"bswap.2",IP);
 136     Value *Tmp1 = new ShiftInst(Instruction::LShr, V,
 137                               ConstantInt::get(Type::Int8Ty,24),"bswap.1", IP);
 138     Tmp3 = BinaryOperator::createAnd(Tmp3,
 139                                      ConstantInt::get(Type::Int32Ty, 0xFF0000),
 140                                      "bswap.and3", IP);
 141     Tmp2 = BinaryOperator::createAnd(Tmp2,
 142                                      ConstantInt::get(Type::Int32Ty, 0xFF00),
 143                                      "bswap.and2", IP);
 144     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or1", IP);
 145     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or2", IP);
 146     V = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.i32", IP);
 147     break;
 148   }
 149   case 64: {
 150     Value *Tmp8 = new ShiftInst(Instruction::Shl, V,
 151                               ConstantInt::get(Type::Int8Ty,56),"bswap.8", IP);
 152     Value *Tmp7 = new ShiftInst(Instruction::Shl, V,
 153                               ConstantInt::get(Type::Int8Ty,40),"bswap.7", IP);
 154     Value *Tmp6 = new ShiftInst(Instruction::Shl, V,
 155                               ConstantInt::get(Type::Int8Ty,24),"bswap.6", IP);
 156     Value *Tmp5 = new ShiftInst(Instruction::Shl, V,
 157                               ConstantInt::get(Type::Int8Ty,8),"bswap.5", IP);
 158     Value* Tmp4 = new ShiftInst(Instruction::LShr, V,
 159                               ConstantInt::get(Type::Int8Ty,8),"bswap.4", IP);
 160     Value* Tmp3 = new ShiftInst(Instruction::LShr, V,
 161                               ConstantInt::get(Type::Int8Ty,24),"bswap.3", IP);
 162     Value* Tmp2 = new ShiftInst(Instruction::LShr, V,
 163                               ConstantInt::get(Type::Int8Ty,40),"bswap.2", IP);
 164     Value* Tmp1 = new ShiftInst(Instruction::LShr, V,
 165                               ConstantInt::get(Type::Int8Ty,56),"bswap.1", IP);
 166     Tmp7 = BinaryOperator::createAnd(Tmp7,
 167                              ConstantInt::get(Type::Int64Ty,
 168                                0xFF000000000000ULL),
 169                              "bswap.and7", IP);
 170     Tmp6 = BinaryOperator::createAnd(Tmp6,
 171                              ConstantInt::get(Type::Int64Ty, 0xFF0000000000ULL),
 172                              "bswap.and6", IP);
 173     Tmp5 = BinaryOperator::createAnd(Tmp5,
 174                              ConstantInt::get(Type::Int64Ty, 0xFF00000000ULL),
 175                              "bswap.and5", IP);
 176     Tmp4 = BinaryOperator::createAnd(Tmp4,
 177                              ConstantInt::get(Type::Int64Ty, 0xFF000000ULL),
 178                              "bswap.and4", IP);
 179     Tmp3 = BinaryOperator::createAnd(Tmp3,
 180                              ConstantInt::get(Type::Int64Ty, 0xFF0000ULL),
 181                              "bswap.and3", IP);
 182     Tmp2 = BinaryOperator::createAnd(Tmp2,
 183                              ConstantInt::get(Type::Int64Ty, 0xFF00ULL),
 184                              "bswap.and2", IP);
 185     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp7, "bswap.or1", IP);
 186     Tmp6 = BinaryOperator::createOr(Tmp6, Tmp5, "bswap.or2", IP);
 187     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp3, "bswap.or3", IP);
 188     Tmp2 = BinaryOperator::createOr(Tmp2, Tmp1, "bswap.or4", IP);
 189     Tmp8 = BinaryOperator::createOr(Tmp8, Tmp6, "bswap.or5", IP);
 190     Tmp4 = BinaryOperator::createOr(Tmp4, Tmp2, "bswap.or6", IP);
 191     V = BinaryOperator::createOr(Tmp8, Tmp4, "bswap.i64", IP);
 192     break;
 193   }
 194   }
 195   return V;
 196 }
 197
 198 /// LowerCTPOP - Emit the code to lower ctpop of V before the specified
 199 /// instruction IP.
 200 static Value *LowerCTPOP(Value *V, Instruction *IP) {
 201   assert(V->getType()->isInteger() && "Can't ctpop a non-integer type!");
 202
 203   static const uint64_t MaskValues[6] = {
 204     0x5555555555555555ULL, 0x3333333333333333ULL,
 205     0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
 206     0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
 207   };
 208
 209   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 210
 211   for (unsigned i = 1, ct = 0; i != BitSize; i <<= 1, ++ct) {
 212     Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]);
 213     Value *LHS = BinaryOperator::createAnd(V, MaskCst, "cppop.and1", IP);
 214     Value *VShift = new ShiftInst(Instruction::LShr, V,
 215                       ConstantInt::get(Type::Int8Ty, i), "ctpop.sh", IP);
 216     Value *RHS = BinaryOperator::createAnd(VShift, MaskCst, "cppop.and2", IP);
 217     V = BinaryOperator::createAdd(LHS, RHS, "ctpop.step", IP);
 218   }
 219
 220   return V;
 221 }
 222
 223 /// LowerCTLZ - Emit the code to lower ctlz of V before the specified
 224 /// instruction IP.
 225 static Value *LowerCTLZ(Value *V, Instruction *IP) {
 226
 227   unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
 228   for (unsigned i = 1; i != BitSize; i <<= 1) {
 229     Value *ShVal = ConstantInt::get(Type::Int8Ty, i);
 230     ShVal = new ShiftInst(Instruction::LShr, V, ShVal, "ctlz.sh", IP);
 231     V = BinaryOperator::createOr(V, ShVal, "ctlz.step", IP);
 232   }
 233
 234   V = BinaryOperator::createNot(V, "", IP);
 235   return LowerCTPOP(V, IP);
 236 }
 237
 238
 239
 240 void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
 241   Function *Callee = CI->getCalledFunction();
 242   assert(Callee && "Cannot lower an indirect call!");
 243
 244   switch (Callee->getIntrinsicID()) {
 245   case Intrinsic::not_intrinsic:
 246     cerr << "Cannot lower a call to a non-intrinsic function '"
 247          << Callee->getName() << "'!\n";
 248     abort();
 249   default:
 250     cerr << "Error: Code generator does not support intrinsic function '"
 251          << Callee->getName() << "'!\n";
 252     abort();
 253
 254     // The setjmp/longjmp intrinsics should only exist in the code if it was
 255     // never optimized (ie, right out of the CFE), or if it has been hacked on
 256     // by the lowerinvoke pass.  In both cases, the right thing to do is to
 257     // convert the call to an explicit setjmp or longjmp call.
 258   case Intrinsic::setjmp: {
 259     static Constant *SetjmpFCache = 0;
 260     Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(),
 261                                Type::Int32Ty, SetjmpFCache);
 262     if (CI->getType() != Type::VoidTy)
 263       CI->replaceAllUsesWith(V);
 264     break;
 265   }
 266   case Intrinsic::sigsetjmp:
 267      if (CI->getType() != Type::VoidTy)
 268        CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 269      break;
 270
 271   case Intrinsic::longjmp: {
 272     static Constant *LongjmpFCache = 0;
 273     ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(),
 274                     Type::VoidTy, LongjmpFCache);
 275     break;
 276   }
 277
 278   case Intrinsic::siglongjmp: {
 279     // Insert the call to abort
 280     static Constant *AbortFCache = 0;
 281     ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(),
 282                     Type::VoidTy, AbortFCache);
 283     break;
 284   }
 285   case Intrinsic::ctpop_i8:
 286   case Intrinsic::ctpop_i16:
 287   case Intrinsic::ctpop_i32:
 288   case Intrinsic::ctpop_i64:
 289     CI->replaceAllUsesWith(LowerCTPOP(CI->getOperand(1), CI));
 290     break;
 291
 292   case Intrinsic::bswap_i16:
 293   case Intrinsic::bswap_i32:
 294   case Intrinsic::bswap_i64:
 295     CI->replaceAllUsesWith(LowerBSWAP(CI->getOperand(1), CI));
 296     break;
 297
 298   case Intrinsic::ctlz_i8:
 299   case Intrinsic::ctlz_i16:
 300   case Intrinsic::ctlz_i32:
 301   case Intrinsic::ctlz_i64:
 302     CI->replaceAllUsesWith(LowerCTLZ(CI->getOperand(1), CI));
 303     break;
 304
 305   case Intrinsic::cttz_i8:
 306   case Intrinsic::cttz_i16:
 307   case Intrinsic::cttz_i32:
 308   case Intrinsic::cttz_i64: {
 309     // cttz(x) -> ctpop(~X & (X-1))
 310     Value *Src = CI->getOperand(1);
 311     Value *NotSrc = BinaryOperator::createNot(Src, Src->getName()+".not", CI);
 312     Value *SrcM1  = ConstantInt::get(Src->getType(), 1);
 313     SrcM1 = BinaryOperator::createSub(Src, SrcM1, "", CI);
 314     Src = LowerCTPOP(BinaryOperator::createAnd(NotSrc, SrcM1, "", CI), CI);
 315     CI->replaceAllUsesWith(Src);
 316     break;
 317   }
 318
 319   case Intrinsic::stacksave:
 320   case Intrinsic::stackrestore: {
 321     static bool Warned = false;
 322     if (!Warned)
 323       cerr << "WARNING: this target does not support the llvm.stack"
 324            << (Callee->getIntrinsicID() == Intrinsic::stacksave ?
 325                "save" : "restore") << " intrinsic.\n";
 326     Warned = true;
 327     if (Callee->getIntrinsicID() == Intrinsic::stacksave)
 328       CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
 329     break;
 330   }
 331
 332   case Intrinsic::returnaddress:
 333   case Intrinsic::frameaddress:
 334     cerr << "WARNING: this target does not support the llvm."
 335          << (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
 336              "return" : "frame") << "address intrinsic.\n";
 337     CI->replaceAllUsesWith(ConstantPointerNull::get(
 338                                             cast<PointerType>(CI->getType())));
 339     break;
 340
 341   case Intrinsic::prefetch:
 342     break;    // Simply strip out prefetches on unsupported architectures
 343
 344   case Intrinsic::pcmarker:
 345     break;    // Simply strip out pcmarker on unsupported architectures
 346   case Intrinsic::readcyclecounter: {
 347     cerr << "WARNING: this target does not support the llvm.readcyclecoun"
 348          << "ter intrinsic.  It is being lowered to a constant 0\n";
 349     CI->replaceAllUsesWith(ConstantInt::get(Type::Int64Ty, 0));
 350     break;
 351   }
 352
 353   case Intrinsic::dbg_stoppoint:
 354   case Intrinsic::dbg_region_start:
 355   case Intrinsic::dbg_region_end:
 356   case Intrinsic::dbg_func_start:
 357   case Intrinsic::dbg_declare:
 358     break;    // Simply strip out debugging intrinsics
 359
 360   case Intrinsic::memcpy_i32: {
 361     static Constant *MemcpyFCache = 0;
 362     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 363                     (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 364     break;
 365   }
 366   case Intrinsic::memcpy_i64: {
 367     static Constant *MemcpyFCache = 0;
 368     ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1,
 369                      (*(CI->op_begin()+1))->getType(), MemcpyFCache);
 370     break;
 371   }
 372   case Intrinsic::memmove_i32: {
 373     static Constant *MemmoveFCache = 0;
 374     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 375                     (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 376     break;
 377   }
 378   case Intrinsic::memmove_i64: {
 379     static Constant *MemmoveFCache = 0;
 380     ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1,
 381                     (*(CI->op_begin()+1))->getType(), MemmoveFCache);
 382     break;
 383   }
 384   case Intrinsic::memset_i32: {
 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   }
 389   case Intrinsic::memset_i64: {
 390     static Constant *MemsetFCache = 0;
 391     ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1,
 392                     (*(CI->op_begin()+1))->getType(), MemsetFCache);
 393     break;
 394   }
 395   case Intrinsic::isunordered_f32:
 396   case Intrinsic::isunordered_f64: {
 397     Value *L = CI->getOperand(1);
 398     Value *R = CI->getOperand(2);
 399
 400     Value *LIsNan = new FCmpInst(FCmpInst::FCMP_ONE, L, L, "LIsNan", CI);
 401     Value *RIsNan = new FCmpInst(FCmpInst::FCMP_ONE, R, R, "RIsNan", CI);
 402     CI->replaceAllUsesWith(
 403       BinaryOperator::create(Instruction::Or, LIsNan, RIsNan,
 404                              "isunordered", CI));
 405     break;
 406   }
 407   case Intrinsic::sqrt_f32: {
 408     static Constant *sqrtfFCache = 0;
 409     ReplaceCallWith("sqrtf", CI, CI->op_begin()+1, CI->op_end(),
 410                     Type::FloatTy, sqrtfFCache);
 411     break;
 412   }
 413   case Intrinsic::sqrt_f64: {
 414     static Constant *sqrtFCache = 0;
 415     ReplaceCallWith("sqrt", CI, CI->op_begin()+1, CI->op_end(),
 416                     Type::DoubleTy, sqrtFCache);
 417     break;
 418   }
 419   }
 420
 421   assert(CI->use_empty() &&
 422          "Lowering should have eliminated any uses of the intrinsic call!");
 423   CI->eraseFromParent();
 424 }