1 //===- llvm/Analysis/MemoryBuiltins.h- Calls to memory builtins -*- C++ -*-===// 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 family of functions identifies calls to builtin functions that allocate 11 // or free memory. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ANALYSIS_MEMORYBUILTINS_H 16 #define LLVM_ANALYSIS_MEMORYBUILTINS_H 17 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/SmallPtrSet.h" 20 #include "llvm/IR/IRBuilder.h" 21 #include "llvm/IR/Operator.h" 22 #include "llvm/InstVisitor.h" 23 #include "llvm/Support/DataTypes.h" 24 #include "llvm/Support/TargetFolder.h" 25 #include "llvm/Support/ValueHandle.h" 26 27 namespace llvm { 28 class CallInst; 29 class PointerType; 30 class DataLayout; 31 class TargetLibraryInfo; 32 class Type; 33 class Value; 34 35 36 /// \brief Tests if a value is a call or invoke to a library function that 37 /// allocates or reallocates memory (either malloc, calloc, realloc, or strdup 38 /// like). 39 bool isAllocationFn(const Value *V, const TargetLibraryInfo *TLI, 40 bool LookThroughBitCast = false); 41 42 /// \brief Tests if a value is a call or invoke to a function that returns a 43 /// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions). 44 bool isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI, 45 bool LookThroughBitCast = false); 46 47 /// \brief Tests if a value is a call or invoke to a library function that 48 /// allocates uninitialized memory (such as malloc). 49 bool isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI, 50 bool LookThroughBitCast = false); 51 52 /// \brief Tests if a value is a call or invoke to a library function that 53 /// allocates zero-filled memory (such as calloc). 54 bool isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI, 55 bool LookThroughBitCast = false); 56 57 /// \brief Tests if a value is a call or invoke to a library function that 58 /// allocates memory (either malloc, calloc, or strdup like). 59 bool isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI, 60 bool LookThroughBitCast = false); 61 62 /// \brief Tests if a value is a call or invoke to a library function that 63 /// reallocates memory (such as realloc). 64 bool isReallocLikeFn(const Value *V, const TargetLibraryInfo *TLI, 65 bool LookThroughBitCast = false); 66 67 68 //===----------------------------------------------------------------------===// 69 // malloc Call Utility Functions. 70 // 71 72 /// extractMallocCall - Returns the corresponding CallInst if the instruction 73 /// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we 74 /// ignore InvokeInst here. 75 const CallInst *extractMallocCall(const Value *I, const TargetLibraryInfo *TLI); 76 static inline CallInst *extractMallocCall(Value *I, 77 const TargetLibraryInfo *TLI) { 78 return const_cast<CallInst*>(extractMallocCall((const Value*)I, TLI)); 79 } 80 81 /// isArrayMalloc - Returns the corresponding CallInst if the instruction 82 /// is a call to malloc whose array size can be determined and the array size 83 /// is not constant 1. Otherwise, return NULL. 84 const CallInst *isArrayMalloc(const Value *I, const DataLayout *TD, 85 const TargetLibraryInfo *TLI); 86 87 /// getMallocType - Returns the PointerType resulting from the malloc call. 88 /// The PointerType depends on the number of bitcast uses of the malloc call: 89 /// 0: PointerType is the malloc calls' return type. 90 /// 1: PointerType is the bitcast's result type. 91 /// >1: Unique PointerType cannot be determined, return NULL. 92 PointerType *getMallocType(const CallInst *CI, const TargetLibraryInfo *TLI); 93 94 /// getMallocAllocatedType - Returns the Type allocated by malloc call. 95 /// The Type depends on the number of bitcast uses of the malloc call: 96 /// 0: PointerType is the malloc calls' return type. 97 /// 1: PointerType is the bitcast's result type. 98 /// >1: Unique PointerType cannot be determined, return NULL. 99 Type *getMallocAllocatedType(const CallInst *CI, const TargetLibraryInfo *TLI); 100 101 /// getMallocArraySize - Returns the array size of a malloc call. If the 102 /// argument passed to malloc is a multiple of the size of the malloced type, 103 /// then return that multiple. For non-array mallocs, the multiple is 104 /// constant 1. Otherwise, return NULL for mallocs whose array size cannot be 105 /// determined. 106 Value *getMallocArraySize(CallInst *CI, const DataLayout *TD, 107 const TargetLibraryInfo *TLI, 108 bool LookThroughSExt = false); 109 110 111 //===----------------------------------------------------------------------===// 112 // calloc Call Utility Functions. 113 // 114 115 /// extractCallocCall - Returns the corresponding CallInst if the instruction 116 /// is a calloc call. 117 const CallInst *extractCallocCall(const Value *I, const TargetLibraryInfo *TLI); 118 static inline CallInst *extractCallocCall(Value *I, 119 const TargetLibraryInfo *TLI) { 120 return const_cast<CallInst*>(extractCallocCall((const Value*)I, TLI)); 121 } 122 123 124 //===----------------------------------------------------------------------===// 125 // free Call Utility Functions. 126 // 127 128 /// isFreeCall - Returns non-null if the value is a call to the builtin free() 129 const CallInst *isFreeCall(const Value *I, const TargetLibraryInfo *TLI); 130 131 static inline CallInst *isFreeCall(Value *I, const TargetLibraryInfo *TLI) { 132 return const_cast<CallInst*>(isFreeCall((const Value*)I, TLI)); 133 } 134 135 136 //===----------------------------------------------------------------------===// 137 // Utility functions to compute size of objects. 138 // 139 140 /// \brief Compute the size of the object pointed by Ptr. Returns true and the 141 /// object size in Size if successful, and false otherwise. In this context, by 142 /// object we mean the region of memory starting at Ptr to the end of the 143 /// underlying object pointed to by Ptr. 144 /// If RoundToAlign is true, then Size is rounded up to the aligment of allocas, 145 /// byval arguments, and global variables. 146 bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout *TD, 147 const TargetLibraryInfo *TLI, bool RoundToAlign = false); 148 149 150 151 typedef std::pair<APInt, APInt> SizeOffsetType; 152 153 /// \brief Evaluate the size and offset of an object pointed to by a Value* 154 /// statically. Fails if size or offset are not known at compile time. 155 class ObjectSizeOffsetVisitor 156 : public InstVisitor<ObjectSizeOffsetVisitor, SizeOffsetType> { 157 158 const DataLayout *TD; 159 const TargetLibraryInfo *TLI; 160 bool RoundToAlign; 161 unsigned IntTyBits; 162 APInt Zero; 163 SmallPtrSet<Instruction *, 8> SeenInsts; 164 165 APInt align(APInt Size, uint64_t Align); 166 167 SizeOffsetType unknown() { 168 return std::make_pair(APInt(), APInt()); 169 } 170 171 public: 172 ObjectSizeOffsetVisitor(const DataLayout *TD, const TargetLibraryInfo *TLI, 173 LLVMContext &Context, bool RoundToAlign = false); 174 175 SizeOffsetType compute(Value *V); 176 177 bool knownSize(SizeOffsetType &SizeOffset) { 178 return SizeOffset.first.getBitWidth() > 1; 179 } 180 181 bool knownOffset(SizeOffsetType &SizeOffset) { 182 return SizeOffset.second.getBitWidth() > 1; 183 } 184 185 bool bothKnown(SizeOffsetType &SizeOffset) { 186 return knownSize(SizeOffset) && knownOffset(SizeOffset); 187 } 188 189 SizeOffsetType visitAllocaInst(AllocaInst &I); 190 SizeOffsetType visitArgument(Argument &A); 191 SizeOffsetType visitCallSite(CallSite CS); 192 SizeOffsetType visitConstantPointerNull(ConstantPointerNull&); 193 SizeOffsetType visitExtractElementInst(ExtractElementInst &I); 194 SizeOffsetType visitExtractValueInst(ExtractValueInst &I); 195 SizeOffsetType visitGEPOperator(GEPOperator &GEP); 196 SizeOffsetType visitGlobalAlias(GlobalAlias &GA); 197 SizeOffsetType visitGlobalVariable(GlobalVariable &GV); 198 SizeOffsetType visitIntToPtrInst(IntToPtrInst&); 199 SizeOffsetType visitLoadInst(LoadInst &I); 200 SizeOffsetType visitPHINode(PHINode&); 201 SizeOffsetType visitSelectInst(SelectInst &I); 202 SizeOffsetType visitUndefValue(UndefValue&); 203 SizeOffsetType visitInstruction(Instruction &I); 204 }; 205 206 typedef std::pair<Value*, Value*> SizeOffsetEvalType; 207 208 209 /// \brief Evaluate the size and offset of an object pointed to by a Value*. 210 /// May create code to compute the result at run-time. 211 class ObjectSizeOffsetEvaluator 212 : public InstVisitor<ObjectSizeOffsetEvaluator, SizeOffsetEvalType> { 213 214 typedef IRBuilder<true, TargetFolder> BuilderTy; 215 typedef std::pair<WeakVH, WeakVH> WeakEvalType; 216 typedef DenseMap<const Value*, WeakEvalType> CacheMapTy; 217 typedef SmallPtrSet<const Value*, 8> PtrSetTy; 218 219 const DataLayout *TD; 220 const TargetLibraryInfo *TLI; 221 LLVMContext &Context; 222 BuilderTy Builder; 223 IntegerType *IntTy; 224 Value *Zero; 225 CacheMapTy CacheMap; 226 PtrSetTy SeenVals; 227 228 SizeOffsetEvalType unknown() { 229 return std::make_pair((Value*)0, (Value*)0); 230 } 231 SizeOffsetEvalType compute_(Value *V); 232 233 public: 234 ObjectSizeOffsetEvaluator(const DataLayout *TD, const TargetLibraryInfo *TLI, 235 LLVMContext &Context); 236 SizeOffsetEvalType compute(Value *V); 237 238 bool knownSize(SizeOffsetEvalType SizeOffset) { 239 return SizeOffset.first; 240 } 241 242 bool knownOffset(SizeOffsetEvalType SizeOffset) { 243 return SizeOffset.second; 244 } 245 246 bool anyKnown(SizeOffsetEvalType SizeOffset) { 247 return knownSize(SizeOffset) || knownOffset(SizeOffset); 248 } 249 250 bool bothKnown(SizeOffsetEvalType SizeOffset) { 251 return knownSize(SizeOffset) && knownOffset(SizeOffset); 252 } 253 254 SizeOffsetEvalType visitAllocaInst(AllocaInst &I); 255 SizeOffsetEvalType visitCallSite(CallSite CS); 256 SizeOffsetEvalType visitExtractElementInst(ExtractElementInst &I); 257 SizeOffsetEvalType visitExtractValueInst(ExtractValueInst &I); 258 SizeOffsetEvalType visitGEPOperator(GEPOperator &GEP); 259 SizeOffsetEvalType visitIntToPtrInst(IntToPtrInst&); 260 SizeOffsetEvalType visitLoadInst(LoadInst &I); 261 SizeOffsetEvalType visitPHINode(PHINode &PHI); 262 SizeOffsetEvalType visitSelectInst(SelectInst &I); 263 SizeOffsetEvalType visitInstruction(Instruction &I); 264 }; 265 266 } // End llvm namespace 267 268 #endif 269
