IntrinsicLowering.cpp revision 9b700f7951b07cb7be885c7560066c73733ef101
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/IntrinsicLowering.h" 15#include "llvm/Constants.h" 16#include "llvm/DerivedTypes.h" 17#include "llvm/Module.h" 18#include "llvm/iOther.h" 19using namespace llvm; 20 21/// ReplaceCallWith - This function is used when we want to lower an intrinsic 22/// call to a call of an external function. This handles hard cases such as 23/// when there was already a prototype for the external function, and if that 24/// prototype doesn't match the arguments we expect to pass in. 25template <class ArgIt> 26static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI, 27 ArgIt ArgBegin, ArgIt ArgEnd, 28 const Type *RetTy, Function *&FCache) { 29 if (!FCache) { 30 // If we haven't already looked up this function, check to see if the 31 // program already contains a function with this name. 32 Module *M = CI->getParent()->getParent()->getParent(); 33 FCache = M->getNamedFunction(NewFn); 34 if (!FCache) { 35 // It doesn't already exist in the program, insert a new definition now. 36 std::vector<const Type *> ParamTys; 37 for (ArgIt I = ArgBegin; I != ArgEnd; ++I) 38 ParamTys.push_back((*I)->getType()); 39 FCache = M->getOrInsertFunction(NewFn, 40 FunctionType::get(RetTy, ParamTys, false)); 41 } 42 } 43 44 const FunctionType *FT = FCache->getFunctionType(); 45 std::vector<Value*> Operands; 46 unsigned ArgNo = 0; 47 for (ArgIt I = ArgBegin; I != ArgEnd && ArgNo != FT->getNumParams(); 48 ++I, ++ArgNo) { 49 Value *Arg = *I; 50 if (Arg->getType() != FT->getParamType(ArgNo)) 51 Arg = new CastInst(Arg, FT->getParamType(ArgNo), Arg->getName(), CI); 52 Operands.push_back(Arg); 53 } 54 // Pass nulls into any additional arguments... 55 for (; ArgNo != FT->getNumParams(); ++ArgNo) 56 Operands.push_back(Constant::getNullValue(FT->getParamType(ArgNo))); 57 58 std::string Name = CI->getName(); CI->setName(""); 59 if (FT->getReturnType() == Type::VoidTy) Name.clear(); 60 return new CallInst(FCache, Operands, Name, CI); 61} 62 63 64void DefaultIntrinsicLowering::LowerIntrinsicCall(CallInst *CI) { 65 Function *Callee = CI->getCalledFunction(); 66 assert(Callee && "Cannot lower an indirect call!"); 67 68 Module *M = Callee->getParent(); 69 70 switch (Callee->getIntrinsicID()) { 71 case Intrinsic::not_intrinsic: 72 std::cerr << "Cannot lower a call to a non-intrinsic function '" 73 << Callee->getName() << "'!\n"; 74 abort(); 75 default: 76 std::cerr << "Error: Code generator does not support intrinsic function '" 77 << Callee->getName() << "'!\n"; 78 abort(); 79 80 // The setjmp/longjmp intrinsics should only exist in the code if it was 81 // never optimized (ie, right out of the CFE), or if it has been hacked on 82 // by the lowerinvoke pass. In both cases, the right thing to do is to 83 // convert the call to an explicit setjmp or longjmp call. 84 case Intrinsic::setjmp: { 85 static Function *SetjmpFCache = 0; 86 Value *V = ReplaceCallWith("setjmp", CI, CI->op_begin()+1, CI->op_end(), 87 Type::IntTy, SetjmpFCache); 88 if (CI->getType() != Type::VoidTy) 89 CI->replaceAllUsesWith(V); 90 break; 91 } 92 case Intrinsic::sigsetjmp: 93 if (CI->getType() != Type::VoidTy) 94 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 95 break; 96 97 case Intrinsic::longjmp: 98 static Function *LongjmpFCache = 0; 99 ReplaceCallWith("longjmp", CI, CI->op_begin()+1, CI->op_end(), 100 Type::VoidTy, LongjmpFCache); 101 break; 102 103 case Intrinsic::siglongjmp: 104 // Insert the call to abort 105 static Function *AbortFCache = 0; 106 ReplaceCallWith("abort", CI, CI->op_end(), CI->op_end(), Type::VoidTy, 107 AbortFCache); 108 break; 109 110 case Intrinsic::returnaddress: 111 case Intrinsic::frameaddress: 112 std::cerr << "WARNING: this target does not support the llvm." 113 << (Callee->getIntrinsicID() == Intrinsic::returnaddress ? 114 "return" : "frame") << "address intrinsic.\n"; 115 CI->replaceAllUsesWith(ConstantPointerNull::get( 116 cast<PointerType>(CI->getType()))); 117 break; 118 119 case Intrinsic::dbg_stoppoint: 120 case Intrinsic::dbg_region_start: 121 case Intrinsic::dbg_region_end: 122 case Intrinsic::dbg_declare: 123 case Intrinsic::dbg_func_start: 124 if (CI->getType() != Type::VoidTy) 125 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType())); 126 break; // Simply strip out debugging intrinsics 127 128 case Intrinsic::memcpy: 129 // The memcpy intrinsic take an extra alignment argument that the memcpy 130 // libc function does not. 131 static Function *MemcpyFCache = 0; 132 ReplaceCallWith("memcpy", CI, CI->op_begin()+1, CI->op_end()-1, 133 (*(CI->op_begin()+1))->getType(), MemcpyFCache); 134 break; 135 case Intrinsic::memmove: 136 // The memmove intrinsic take an extra alignment argument that the memmove 137 // libc function does not. 138 static Function *MemmoveFCache = 0; 139 ReplaceCallWith("memmove", CI, CI->op_begin()+1, CI->op_end()-1, 140 (*(CI->op_begin()+1))->getType(), MemmoveFCache); 141 break; 142 case Intrinsic::memset: 143 // The memset intrinsic take an extra alignment argument that the memset 144 // libc function does not. 145 static Function *MemsetFCache = 0; 146 ReplaceCallWith("memset", CI, CI->op_begin()+1, CI->op_end()-1, 147 (*(CI->op_begin()+1))->getType(), MemsetFCache); 148 break; 149 } 150 151 assert(CI->use_empty() && 152 "Lowering should have eliminated any uses of the intrinsic call!"); 153 CI->getParent()->getInstList().erase(CI); 154} 155