lib/VMCore/AutoUpgrade.cpp

   1 //===-- AutoUpgrade.cpp - Implement auto-upgrade helper functions ---------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the auto-upgrade helper functions
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/AutoUpgrade.h"
  15 #include "llvm/Constants.h"
  16 #include "llvm/Function.h"
  17 #include "llvm/LLVMContext.h"
  18 #include "llvm/Module.h"
  19 #include "llvm/IntrinsicInst.h"
  20 #include "llvm/ADT/SmallVector.h"
  21 #include "llvm/Support/CallSite.h"
  22 #include "llvm/Support/ErrorHandling.h"
  23 #include "llvm/Support/IRBuilder.h"
  24 #include <cstring>
  25 using namespace llvm;
  26
  27
  28 static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
  29   assert(F && "Illegal to upgrade a non-existent Function.");
  30
  31   // Quickly eliminate it, if it's not a candidate.
  32   StringRef Name = F->getName();
  33   if (Name.size() <= 8 || !Name.startswith("llvm."))
  34     return false;
  35   Name = Name.substr(5); // Strip off "llvm."
  36
  37   const FunctionType *FTy = F->getFunctionType();
  38   Module *M = F->getParent();
  39
  40   switch (Name[0]) {
  41   default: break;
  42   case 'p':
  43     //  This upgrades the llvm.prefetch intrinsic to accept one more parameter,
  44     //  which is a instruction / data cache identifier. The old version only
  45     //  implicitly accepted the data version.
  46     if (Name == "prefetch") {
  47       // Don't do anything if it has the correct number of arguments already
  48       if (FTy->getNumParams() == 4)
  49         break;
  50
  51       assert(FTy->getNumParams() == 3 && "old prefetch takes 3 args!");
  52       //  We first need to change the name of the old (bad) intrinsic, because
  53       //  its type is incorrect, but we cannot overload that name. We
  54       //  arbitrarily unique it here allowing us to construct a correctly named
  55       //  and typed function below.
  56       std::string NameTmp = F->getName();
  57       F->setName("");
  58       NewFn = cast<Function>(M->getOrInsertFunction(NameTmp,
  59                                                     FTy->getReturnType(),
  60                                                     FTy->getParamType(0),
  61                                                     FTy->getParamType(1),
  62                                                     FTy->getParamType(2),
  63                                                     FTy->getParamType(2),
  64                                                     (Type*)0));
  65       return true;
  66     }
  67
  68     break;
  69   case 'x': {
  70     const char *NewFnName = NULL;
  71     // This fixes the poorly named crc32 intrinsics.
  72     if (Name == "x86.sse42.crc32.8")
  73       NewFnName = "llvm.x86.sse42.crc32.32.8";
  74     else if (Name == "x86.sse42.crc32.16")
  75       NewFnName = "llvm.x86.sse42.crc32.32.16";
  76     else if (Name == "x86.sse42.crc32.32")
  77       NewFnName = "llvm.x86.sse42.crc32.32.32";
  78     else if (Name == "x86.sse42.crc64.8")
  79       NewFnName = "llvm.x86.sse42.crc32.64.8";
  80     else if (Name == "x86.sse42.crc64.64")
  81       NewFnName = "llvm.x86.sse42.crc32.64.64";
  82
  83     if (NewFnName) {
  84       F->setName(NewFnName);
  85       NewFn = F;
  86       return true;
  87     }
  88
  89     // Calls to these instructions are transformed into unaligned loads.
  90     if (Name == "x86.sse.loadu.ps" || Name == "x86.sse2.loadu.dq" ||
  91         Name == "x86.sse2.loadu.pd")
  92       return true;
  93
  94     // Calls to these instructions are transformed into nontemporal stores.
  95     if (Name == "x86.sse.movnt.ps"  || Name == "x86.sse2.movnt.dq" ||
  96         Name == "x86.sse2.movnt.pd" || Name == "x86.sse2.movnt.i")
  97       return true;
  98
  99     break;
 100   }
 101   }
 102
 103   //  This may not belong here. This function is effectively being overloaded
 104   //  to both detect an intrinsic which needs upgrading, and to provide the
 105   //  upgraded form of the intrinsic. We should perhaps have two separate
 106   //  functions for this.
 107   return false;
 108 }
 109
 110 bool llvm::UpgradeIntrinsicFunction(Function *F, Function *&NewFn) {
 111   NewFn = 0;
 112   bool Upgraded = UpgradeIntrinsicFunction1(F, NewFn);
 113
 114   // Upgrade intrinsic attributes.  This does not change the function.
 115   if (NewFn)
 116     F = NewFn;
 117   if (unsigned id = F->getIntrinsicID())
 118     F->setAttributes(Intrinsic::getAttributes((Intrinsic::ID)id));
 119   return Upgraded;
 120 }
 121
 122 bool llvm::UpgradeGlobalVariable(GlobalVariable *GV) {
 123   // Nothing to do yet.
 124   return false;
 125 }
 126
 127 // UpgradeIntrinsicCall - Upgrade a call to an old intrinsic to be a call the
 128 // upgraded intrinsic. All argument and return casting must be provided in
 129 // order to seamlessly integrate with existing context.
 130 void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
 131   Function *F = CI->getCalledFunction();
 132   LLVMContext &C = CI->getContext();
 133   ImmutableCallSite CS(CI);
 134
 135   assert(F && "CallInst has no function associated with it.");
 136
 137   if (!NewFn) {
 138     if (F->getName() == "llvm.x86.sse.loadu.ps" ||
 139         F->getName() == "llvm.x86.sse2.loadu.dq" ||
 140         F->getName() == "llvm.x86.sse2.loadu.pd") {
 141       // Convert to a native, unaligned load.
 142       const Type *VecTy = CI->getType();
 143       const Type *IntTy = IntegerType::get(C, 128);
 144       IRBuilder<> Builder(C);
 145       Builder.SetInsertPoint(CI->getParent(), CI);
 146
 147       Value *BC = Builder.CreateBitCast(CI->getArgOperand(0),
 148                                         PointerType::getUnqual(IntTy),
 149                                         "cast");
 150       LoadInst *LI = Builder.CreateLoad(BC, CI->getName());
 151       LI->setAlignment(1);      // Unaligned load.
 152       BC = Builder.CreateBitCast(LI, VecTy, "new.cast");
 153
 154       // Fix up all the uses with our new load.
 155       if (!CI->use_empty())
 156         CI->replaceAllUsesWith(BC);
 157
 158       // Remove intrinsic.
 159       CI->eraseFromParent();
 160     } else if (F->getName() == "llvm.x86.sse.movnt.ps" ||
 161                F->getName() == "llvm.x86.sse2.movnt.dq" ||
 162                F->getName() == "llvm.x86.sse2.movnt.pd" ||
 163                F->getName() == "llvm.x86.sse2.movnt.i") {
 164       IRBuilder<> Builder(C);
 165       Builder.SetInsertPoint(CI->getParent(), CI);
 166
 167       Module *M = F->getParent();
 168       SmallVector<Value *, 1> Elts;
 169       Elts.push_back(ConstantInt::get(Type::getInt32Ty(C), 1));
 170       MDNode *Node = MDNode::get(C, Elts);
 171
 172       Value *Arg0 = CI->getArgOperand(0);
 173       Value *Arg1 = CI->getArgOperand(1);
 174
 175       // Convert the type of the pointer to a pointer to the stored type.
 176       Value *BC = Builder.CreateBitCast(Arg0,
 177                                         PointerType::getUnqual(Arg1->getType()),
 178                                         "cast");
 179       StoreInst *SI = Builder.CreateStore(Arg1, BC);
 180       SI->setMetadata(M->getMDKindID("nontemporal"), Node);
 181       SI->setAlignment(16);
 182
 183       // Remove intrinsic.
 184       CI->eraseFromParent();
 185     } else {
 186       llvm_unreachable("Unknown function for CallInst upgrade.");
 187     }
 188     return;
 189   }
 190
 191   switch (NewFn->getIntrinsicID()) {
 192   case Intrinsic::prefetch: {
 193     IRBuilder<> Builder(C);
 194     Builder.SetInsertPoint(CI->getParent(), CI);
 195     const llvm::Type *I32Ty = llvm::Type::getInt32Ty(CI->getContext());
 196
 197     // Add the extra "data cache" argument
 198     Value *Operands[4] = { CI->getArgOperand(0), CI->getArgOperand(1),
 199                            CI->getArgOperand(2),
 200                            llvm::ConstantInt::get(I32Ty, 1) };
 201     CallInst *NewCI = CallInst::Create(NewFn, Operands, Operands+4,
 202                                        CI->getName(), CI);
 203     NewCI->setTailCall(CI->isTailCall());
 204     NewCI->setCallingConv(CI->getCallingConv());
 205     //  Handle any uses of the old CallInst.
 206     if (!CI->use_empty())
 207       //  Replace all uses of the old call with the new cast which has the
 208       //  correct type.
 209       CI->replaceAllUsesWith(NewCI);
 210
 211     //  Clean up the old call now that it has been completely upgraded.
 212     CI->eraseFromParent();
 213     break;
 214   }
 215   }
 216 }
 217
 218 // This tests each Function to determine if it needs upgrading. When we find
 219 // one we are interested in, we then upgrade all calls to reflect the new
 220 // function.
 221 void llvm::UpgradeCallsToIntrinsic(Function* F) {
 222   assert(F && "Illegal attempt to upgrade a non-existent intrinsic.");
 223
 224   // Upgrade the function and check if it is a totaly new function.
 225   Function *NewFn;
 226   if (UpgradeIntrinsicFunction(F, NewFn)) {
 227     if (NewFn != F) {
 228       // Replace all uses to the old function with the new one if necessary.
 229       for (Value::use_iterator UI = F->use_begin(), UE = F->use_end();
 230            UI != UE; ) {
 231         if (CallInst *CI = dyn_cast<CallInst>(*UI++))
 232           UpgradeIntrinsicCall(CI, NewFn);
 233       }
 234       // Remove old function, no longer used, from the module.
 235       F->eraseFromParent();
 236     }
 237   }
 238 }
 239
 240 /// This function strips all debug info intrinsics, except for llvm.dbg.declare.
 241 /// If an llvm.dbg.declare intrinsic is invalid, then this function simply
 242 /// strips that use.
 243 void llvm::CheckDebugInfoIntrinsics(Module *M) {
 244   if (Function *FuncStart = M->getFunction("llvm.dbg.func.start")) {
 245     while (!FuncStart->use_empty())
 246       cast<CallInst>(FuncStart->use_back())->eraseFromParent();
 247     FuncStart->eraseFromParent();
 248   }
 249
 250   if (Function *StopPoint = M->getFunction("llvm.dbg.stoppoint")) {
 251     while (!StopPoint->use_empty())
 252       cast<CallInst>(StopPoint->use_back())->eraseFromParent();
 253     StopPoint->eraseFromParent();
 254   }
 255
 256   if (Function *RegionStart = M->getFunction("llvm.dbg.region.start")) {
 257     while (!RegionStart->use_empty())
 258       cast<CallInst>(RegionStart->use_back())->eraseFromParent();
 259     RegionStart->eraseFromParent();
 260   }
 261
 262   if (Function *RegionEnd = M->getFunction("llvm.dbg.region.end")) {
 263     while (!RegionEnd->use_empty())
 264       cast<CallInst>(RegionEnd->use_back())->eraseFromParent();
 265     RegionEnd->eraseFromParent();
 266   }
 267
 268   if (Function *Declare = M->getFunction("llvm.dbg.declare")) {
 269     if (!Declare->use_empty()) {
 270       DbgDeclareInst *DDI = cast<DbgDeclareInst>(Declare->use_back());
 271       if (!isa<MDNode>(DDI->getArgOperand(0)) ||
 272           !isa<MDNode>(DDI->getArgOperand(1))) {
 273         while (!Declare->use_empty()) {
 274           CallInst *CI = cast<CallInst>(Declare->use_back());
 275           CI->eraseFromParent();
 276         }
 277         Declare->eraseFromParent();
 278       }
 279     }
 280   }
 281 }