IntrinsicLowering.cpp revision 954da37bb492b519f5c31dc360f2a142567e08b4
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 default intrinsic lowering implementation. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/CodeGen/IntrinsicLowering.h" 15#include "llvm/Constants.h" 16#include "llvm/DerivedTypes.h" 17#include "llvm/Module.h" 18#include "llvm/iOther.h" 19#include <iostream> 20 21using namespace llvm; 22 23template <class ArgIt> 24static Function *EnsureFunctionExists(Module &M, const char *Name, 25 ArgIt ArgBegin, ArgIt ArgEnd, 26 const Type *RetTy) { 27 if (Function *F = M.getNamedFunction(Name)) return F; 28 // It doesn't already exist in the program, insert a new definition now. 29 std::vector<const Type *> ParamTys; 30 for (ArgIt I = ArgBegin; I != ArgEnd; ++I) 31 ParamTys.push_back(I->getType()); 32 return M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false)); 33} 34 35/// ReplaceCallWith - This function is used when we want to lower an intrinsic 36/// call to a call of an external function. This handles hard cases such as 37/// when there was already a prototype for the external function, and if that 38/// prototype doesn't match the arguments we expect to pass in. 39template <class ArgIt> 40static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI, 41 ArgIt ArgBegin, ArgIt ArgEnd, 42 const Type *RetTy, Function *&FCache) { 43 if (!FCache) { 44 // If we haven't already looked up this function, check to see if the 45 // program already contains a function with this name. 46 Module *M = CI->getParent()->getParent()->getParent(); 47 FCache = M->getNamedFunction(NewFn); 48 if (!FCache) { 49 // It doesn't already exist in the program, insert a new definition now. 50 std::vector<const Type *> ParamTys; 51 for (ArgIt I = ArgBegin; I != ArgEnd; ++I) 52 ParamTys.push_back((*I)->getType()); 53 FCache = M->getOrInsertFunction(NewFn, 54 FunctionType::get(RetTy, ParamTys, false)); 55 } 56 } 57 58 const FunctionType *FT = FCache->getFunctionType(); 59 std::vector<Value*> Operands; 60 unsigned ArgNo = 0; 61 for (ArgIt I = ArgBegin; I != ArgEnd && ArgNo != FT->getNumParams(); 62 ++I, ++ArgNo) { 63 Value *Arg = *I; 64 if (Arg->getType() != FT->getParamType(ArgNo)) 65 Arg = new CastInst(Arg, FT->getParamType(ArgNo), Arg->getName(), CI); 66 Operands.push_back(Arg); 67 } 68 // Pass nulls into any additional arguments... 69 for (; ArgNo != FT->getNumParams(); ++ArgNo) 70 Operands.push_back(Constant::getNullValue(FT->getParamType(ArgNo))); 71 72 std::string Name = CI->getName(); CI->setName(""); 73 if (FT->getReturnType() == Type::VoidTy) Name.clear(); 74 CallInst *NewCI = new CallInst(FCache, Operands, Name, CI); 75 if (!CI->use_empty()) { 76 Value *V = NewCI; 77 if (CI->getType() != NewCI->getType()) 78 V = new CastInst(NewCI, CI->getType(), Name, CI); 79 CI->replaceAllUsesWith(V); 80 } 81 return NewCI; 82} 83 84void DefaultIntrinsicLowering::AddPrototypes(Module &M) { 85 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) 86 if (I->isExternal() && !I->use_empty()) 87 switch (I->getIntrinsicID()) { 88 default: break; 89 case Intrinsic::setjmp: 90 EnsureFunctionExists(M, "setjmp", I->abegin(), I->aend(), Type::IntTy); 91 break; 92 case Intrinsic::longjmp: 93 EnsureFunctionExists(M, "longjmp", I->abegin(), I->aend(),Type::VoidTy); 94 break; 95 case Intrinsic::siglongjmp: 96 EnsureFunctionExists(M, "abort", I->aend(), I->aend(), Type::VoidTy); 97 break; 98 case Intrinsic::memcpy: 99 EnsureFunctionExists(M, "memcpy", I->abegin(), --I->aend(), 100 I->abegin()->getType()); 101 break; 102 case Intrinsic::memmove: 103 EnsureFunctionExists(M, "memmove", I->abegin(), --I->aend(), 104 I->abegin()->getType()); 105 break; 106 case Intrinsic::memset: 107 EnsureFunctionExists(M, "memset", I->abegin(), --I->aend(), 108 I->abegin()->getType()); 109 break; 110 case Intrinsic::isunordered: 111 EnsureFunctionExists(M, "isunordered", I->abegin(), I->aend(), Type::BoolTy); 112 break; 113 } 114 115} 116 117void DefaultIntrinsicLowering::LowerIntrinsicCall(CallInst *CI) { 118 Function *Callee = CI->getCalledFunction(); 119 assert(Callee && "Cannot lower an indirect call!"); 120 121 switch (Callee->getIntrinsicID()) { 122 case Intrinsic::not_intrinsic: 123 std::cerr << "Cannot lower a call to a non-intrinsic function '" 124 << Callee->getName() << "'!\n"; 125 abort(); 126 default: 127 std::cerr << "Error: Code generator does not support intrinsic function '" 128 << Callee->getName() << "'!\n"; 129 abort(); 130 131 // The setjmp/longjmp intrinsics should only exist in the code if it was 132 // never optimized (ie, right out of the CFE), or if it has been hacked on 133 // by the lowerinvoke pass. In both cases, the right thing to do is to 134 // convert the call to an explicit setjmp or longjmp call. 135 case Intrinsic::setjmp: { 136 static Function *SetjmpFCache = 0; 137 Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(), 138 Type::IntTy, SetjmpFCache); 139 if (CI->getType() != Type::VoidTy) 140 CI->replaceAllUsesWith(V); 141 break; 142 } 143 case Intrinsic::sigsetjmp: 144 if (CI->getType() != Type::VoidTy) 145 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 146 break; 147 148 case Intrinsic::longjmp: { 149 static Function *LongjmpFCache = 0; 150 ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(), 151 Type::VoidTy, LongjmpFCache); 152 break; 153 } 154 155 case Intrinsic::siglongjmp: { 156 // Insert the call to abort 157 static Function *AbortFCache = 0; 158 ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(), Type::VoidTy, 159 AbortFCache); 160 break; 161 } 162 163 case Intrinsic::returnaddress: 164 case Intrinsic::frameaddress: 165 std::cerr << "WARNING: this target does not support the llvm." 166 << (Callee->getIntrinsicID() == Intrinsic::returnaddress ? 167 "return" : "frame") << "address intrinsic.\n"; 168 CI->replaceAllUsesWith(ConstantPointerNull::get( 169 cast<PointerType>(CI->getType()))); 170 break; 171 172 case Intrinsic::dbg_stoppoint: 173 case Intrinsic::dbg_region_start: 174 case Intrinsic::dbg_region_end: 175 case Intrinsic::dbg_declare: 176 case Intrinsic::dbg_func_start: 177 if (CI->getType() != Type::VoidTy) 178 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 179 break; // Simply strip out debugging intrinsics 180 181 case Intrinsic::memcpy: { 182 // The memcpy intrinsic take an extra alignment argument that the memcpy 183 // libc function does not. 184 static Function *MemcpyFCache = 0; 185 ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1, 186 (*(CI->op_begin()+1))->getType(), MemcpyFCache); 187 break; 188 } 189 case Intrinsic::memmove: { 190 // The memmove intrinsic take an extra alignment argument that the memmove 191 // libc function does not. 192 static Function *MemmoveFCache = 0; 193 ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1, 194 (*(CI->op_begin()+1))->getType(), MemmoveFCache); 195 break; 196 } 197 case Intrinsic::memset: { 198 // The memset intrinsic take an extra alignment argument that the memset 199 // libc function does not. 200 static Function *MemsetFCache = 0; 201 ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1, 202 (*(CI->op_begin()+1))->getType(), MemsetFCache); 203 break; 204 } 205 case Intrinsic::isunordered: { 206 static Function *isunorderedFCache = 0; 207 ReplaceCallWith("isunordered", CI, CI->op_begin()+1, CI->op_end(), 208 Type::BoolTy, isunorderedFCache); 209 break; 210 } 211 } 212 213 assert(CI->use_empty() && 214 "Lowering should have eliminated any uses of the intrinsic call!"); 215 CI->getParent()->getInstList().erase(CI); 216} 217