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