1 //===- NVVMReflect.cpp - NVVM Emulate conditional compilation -------------===// 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 pass replaces occurrences of __nvvm_reflect("string") with an 11 // integer based on -nvvm-reflect-list string=<int> option given to this pass. 12 // If an undefined string value is seen in a call to __nvvm_reflect("string"), 13 // a default value of 0 will be used. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #include "NVPTX.h" 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/SmallVector.h" 20 #include "llvm/ADT/StringMap.h" 21 #include "llvm/IR/Constants.h" 22 #include "llvm/IR/DerivedTypes.h" 23 #include "llvm/IR/Function.h" 24 #include "llvm/IR/Instructions.h" 25 #include "llvm/IR/Intrinsics.h" 26 #include "llvm/IR/Module.h" 27 #include "llvm/IR/Type.h" 28 #include "llvm/Pass.h" 29 #include "llvm/Support/CommandLine.h" 30 #include "llvm/Support/Debug.h" 31 #include "llvm/Support/raw_os_ostream.h" 32 #include "llvm/Transforms/Scalar.h" 33 #include <map> 34 #include <sstream> 35 #include <string> 36 #include <vector> 37 38 #define NVVM_REFLECT_FUNCTION "__nvvm_reflect" 39 40 using namespace llvm; 41 42 #define DEBUG_TYPE "nvptx-reflect" 43 44 namespace llvm { void initializeNVVMReflectPass(PassRegistry &); } 45 46 namespace { 47 class NVVMReflect : public ModulePass { 48 private: 49 StringMap<int> VarMap; 50 typedef DenseMap<std::string, int>::iterator VarMapIter; 51 52 public: 53 static char ID; 54 NVVMReflect() : ModulePass(ID) { 55 initializeNVVMReflectPass(*PassRegistry::getPassRegistry()); 56 VarMap.clear(); 57 } 58 59 NVVMReflect(const StringMap<int> &Mapping) 60 : ModulePass(ID) { 61 initializeNVVMReflectPass(*PassRegistry::getPassRegistry()); 62 for (StringMap<int>::const_iterator I = Mapping.begin(), E = Mapping.end(); 63 I != E; ++I) { 64 VarMap[(*I).getKey()] = (*I).getValue(); 65 } 66 } 67 68 void getAnalysisUsage(AnalysisUsage &AU) const override { 69 AU.setPreservesAll(); 70 } 71 bool runOnModule(Module &) override; 72 73 private: 74 bool handleFunction(Function *ReflectFunction); 75 void setVarMap(); 76 }; 77 } 78 79 ModulePass *llvm::createNVVMReflectPass() { 80 return new NVVMReflect(); 81 } 82 83 ModulePass *llvm::createNVVMReflectPass(const StringMap<int>& Mapping) { 84 return new NVVMReflect(Mapping); 85 } 86 87 static cl::opt<bool> 88 NVVMReflectEnabled("nvvm-reflect-enable", cl::init(true), cl::Hidden, 89 cl::desc("NVVM reflection, enabled by default")); 90 91 char NVVMReflect::ID = 0; 92 INITIALIZE_PASS(NVVMReflect, "nvvm-reflect", 93 "Replace occurrences of __nvvm_reflect() calls with 0/1", false, 94 false) 95 96 static cl::list<std::string> 97 ReflectList("nvvm-reflect-list", cl::value_desc("name=<int>"), cl::Hidden, 98 cl::desc("A list of string=num assignments"), 99 cl::ValueRequired); 100 101 /// The command line can look as follows : 102 /// -nvvm-reflect-list a=1,b=2 -nvvm-reflect-list c=3,d=0 -R e=2 103 /// The strings "a=1,b=2", "c=3,d=0", "e=2" are available in the 104 /// ReflectList vector. First, each of ReflectList[i] is 'split' 105 /// using "," as the delimiter. Then each of this part is split 106 /// using "=" as the delimiter. 107 void NVVMReflect::setVarMap() { 108 for (unsigned i = 0, e = ReflectList.size(); i != e; ++i) { 109 DEBUG(dbgs() << "Option : " << ReflectList[i] << "\n"); 110 SmallVector<StringRef, 4> NameValList; 111 StringRef(ReflectList[i]).split(NameValList, ","); 112 for (unsigned j = 0, ej = NameValList.size(); j != ej; ++j) { 113 SmallVector<StringRef, 2> NameValPair; 114 NameValList[j].split(NameValPair, "="); 115 assert(NameValPair.size() == 2 && "name=val expected"); 116 std::stringstream ValStream(NameValPair[1]); 117 int Val; 118 ValStream >> Val; 119 assert((!(ValStream.fail())) && "integer value expected"); 120 VarMap[NameValPair[0]] = Val; 121 } 122 } 123 } 124 125 bool NVVMReflect::handleFunction(Function *ReflectFunction) { 126 // Validate _reflect function 127 assert(ReflectFunction->isDeclaration() && 128 "_reflect function should not have a body"); 129 assert(ReflectFunction->getReturnType()->isIntegerTy() && 130 "_reflect's return type should be integer"); 131 132 std::vector<Instruction *> ToRemove; 133 134 // Go through the uses of ReflectFunction in this Function. 135 // Each of them should a CallInst with a ConstantArray argument. 136 // First validate that. If the c-string corresponding to the 137 // ConstantArray can be found successfully, see if it can be 138 // found in VarMap. If so, replace the uses of CallInst with the 139 // value found in VarMap. If not, replace the use with value 0. 140 for (User *U : ReflectFunction->users()) { 141 assert(isa<CallInst>(U) && "Only a call instruction can use _reflect"); 142 CallInst *Reflect = cast<CallInst>(U); 143 144 assert((Reflect->getNumOperands() == 2) && 145 "Only one operand expect for _reflect function"); 146 // In cuda, we will have an extra constant-to-generic conversion of 147 // the string. 148 const Value *Str = Reflect->getArgOperand(0); 149 if (isa<CallInst>(Str)) { 150 // CUDA path 151 const CallInst *ConvCall = cast<CallInst>(Str); 152 Str = ConvCall->getArgOperand(0); 153 } 154 assert(isa<ConstantExpr>(Str) && 155 "Format of _reflect function not recognized"); 156 const ConstantExpr *GEP = cast<ConstantExpr>(Str); 157 158 const Value *Sym = GEP->getOperand(0); 159 assert(isa<Constant>(Sym) && "Format of _reflect function not recognized"); 160 161 const Constant *SymStr = cast<Constant>(Sym); 162 163 assert(isa<ConstantDataSequential>(SymStr->getOperand(0)) && 164 "Format of _reflect function not recognized"); 165 166 assert(cast<ConstantDataSequential>(SymStr->getOperand(0))->isCString() && 167 "Format of _reflect function not recognized"); 168 169 std::string ReflectArg = 170 cast<ConstantDataSequential>(SymStr->getOperand(0))->getAsString(); 171 172 ReflectArg = ReflectArg.substr(0, ReflectArg.size() - 1); 173 DEBUG(dbgs() << "Arg of _reflect : " << ReflectArg << "\n"); 174 175 int ReflectVal = 0; // The default value is 0 176 if (VarMap.find(ReflectArg) != VarMap.end()) { 177 ReflectVal = VarMap[ReflectArg]; 178 } 179 Reflect->replaceAllUsesWith( 180 ConstantInt::get(Reflect->getType(), ReflectVal)); 181 ToRemove.push_back(Reflect); 182 } 183 if (ToRemove.size() == 0) 184 return false; 185 186 for (unsigned i = 0, e = ToRemove.size(); i != e; ++i) 187 ToRemove[i]->eraseFromParent(); 188 return true; 189 } 190 191 bool NVVMReflect::runOnModule(Module &M) { 192 if (!NVVMReflectEnabled) 193 return false; 194 195 setVarMap(); 196 197 198 bool Res = false; 199 std::string Name; 200 Type *Tys[1]; 201 Type *I8Ty = Type::getInt8Ty(M.getContext()); 202 Function *ReflectFunction; 203 204 // Check for standard overloaded versions of llvm.nvvm.reflect 205 206 for (unsigned i = 0; i != 5; ++i) { 207 Tys[0] = PointerType::get(I8Ty, i); 208 Name = Intrinsic::getName(Intrinsic::nvvm_reflect, Tys); 209 ReflectFunction = M.getFunction(Name); 210 if(ReflectFunction != 0) { 211 Res |= handleFunction(ReflectFunction); 212 } 213 } 214 215 ReflectFunction = M.getFunction(NVVM_REFLECT_FUNCTION); 216 // If reflect function is not used, then there will be 217 // no entry in the module. 218 if (ReflectFunction != 0) 219 Res |= handleFunction(ReflectFunction); 220 221 return Res; 222 } 223
