MemoryBuiltins.h revision 10cefaab3fa4270396fa57b3286ab9860fafb60d
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/Operator.h" 21#include "llvm/Support/DataTypes.h" 22#include "llvm/Support/InstVisitor.h" 23#include "llvm/Support/IRBuilder.h" 24#include "llvm/Support/TargetFolder.h" 25 26namespace llvm { 27class CallInst; 28class PointerType; 29class TargetData; 30class Type; 31class Value; 32 33 34/// \brief Tests if a value is a call to a library function that allocates or 35/// reallocates memory (either malloc, calloc, realloc, or strdup like). 36bool isAllocationFn(const Value *V, bool LookThroughBitCast = false); 37 38/// \brief Tests if a value is a call to a function that returns a NoAlias 39/// pointer (including malloc/calloc/strdup-like functions). 40bool isNoAliasFn(const Value *V, bool LookThroughBitCast = false); 41 42/// \brief Tests if a value is a call to a library function that allocates 43/// uninitialized memory (such as malloc). 44bool isMallocLikeFn(const Value *V, bool LookThroughBitCast = false); 45 46/// \brief Tests if a value is a call to a library function that allocates 47/// zero-filled memory (such as calloc). 48bool isCallocLikeFn(const Value *V, bool LookThroughBitCast = false); 49 50/// \brief Tests if a value is a call to a library function that allocates 51/// memory (either malloc, calloc, or strdup like). 52bool isAllocLikeFn(const Value *V, bool LookThroughBitCast = false); 53 54/// \brief Tests if a value is a call to a library function that reallocates 55/// memory (such as realloc). 56bool isReallocLikeFn(const Value *V, bool LookThroughBitCast = false); 57 58 59//===----------------------------------------------------------------------===// 60// malloc Call Utility Functions. 61// 62 63/// extractMallocCall - Returns the corresponding CallInst if the instruction 64/// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we 65/// ignore InvokeInst here. 66const CallInst *extractMallocCall(const Value *I); 67static inline CallInst *extractMallocCall(Value *I) { 68 return const_cast<CallInst*>(extractMallocCall((const Value*)I)); 69} 70 71/// extractMallocCallFromBitCast - Returns the corresponding CallInst if the 72/// instruction is a bitcast of the result of a malloc call. 73const CallInst *extractMallocCallFromBitCast(const Value *I); 74static inline CallInst *extractMallocCallFromBitCast(Value *I) { 75 return const_cast<CallInst*>(extractMallocCallFromBitCast((const Value*)I)); 76} 77 78/// isArrayMalloc - Returns the corresponding CallInst if the instruction 79/// is a call to malloc whose array size can be determined and the array size 80/// is not constant 1. Otherwise, return NULL. 81const CallInst *isArrayMalloc(const Value *I, const TargetData *TD); 82 83/// getMallocType - Returns the PointerType resulting from the malloc call. 84/// The PointerType depends on the number of bitcast uses of the malloc call: 85/// 0: PointerType is the malloc calls' return type. 86/// 1: PointerType is the bitcast's result type. 87/// >1: Unique PointerType cannot be determined, return NULL. 88PointerType *getMallocType(const CallInst *CI); 89 90/// getMallocAllocatedType - Returns the Type allocated by malloc call. 91/// The Type depends on the number of bitcast uses of the malloc call: 92/// 0: PointerType is the malloc calls' return type. 93/// 1: PointerType is the bitcast's result type. 94/// >1: Unique PointerType cannot be determined, return NULL. 95Type *getMallocAllocatedType(const CallInst *CI); 96 97/// getMallocArraySize - Returns the array size of a malloc call. If the 98/// argument passed to malloc is a multiple of the size of the malloced type, 99/// then return that multiple. For non-array mallocs, the multiple is 100/// constant 1. Otherwise, return NULL for mallocs whose array size cannot be 101/// determined. 102Value *getMallocArraySize(CallInst *CI, const TargetData *TD, 103 bool LookThroughSExt = false); 104 105 106//===----------------------------------------------------------------------===// 107// calloc Call Utility Functions. 108// 109 110/// extractCallocCall - Returns the corresponding CallInst if the instruction 111/// is a calloc call. 112const CallInst *extractCallocCall(const Value *I); 113static inline CallInst *extractCallocCall(Value *I) { 114 return const_cast<CallInst*>(extractCallocCall((const Value*)I)); 115} 116 117 118//===----------------------------------------------------------------------===// 119// free Call Utility Functions. 120// 121 122/// isFreeCall - Returns non-null if the value is a call to the builtin free() 123const CallInst *isFreeCall(const Value *I); 124 125static inline CallInst *isFreeCall(Value *I) { 126 return const_cast<CallInst*>(isFreeCall((const Value*)I)); 127} 128 129 130//===----------------------------------------------------------------------===// 131// Utility functions to compute size of objects. 132// 133 134/// \brief Compute the size of the object pointed by Ptr. Returns true and the 135/// object size in Size if successful, and false otherwise. 136/// If RoundToAlign is true, then Size is rounded up to the aligment of allocas, 137/// byval arguments, and global variables. 138bool getObjectSize(const Value *Ptr, uint64_t &Size, const TargetData *TD, 139 bool RoundToAlign = false); 140 141 142 143typedef std::pair<APInt, APInt> SizeOffsetType; 144 145/// \brief Evaluate the size and offset of an object ponted by a Value* 146/// statically. Fails if size or offset are not known at compile time. 147class ObjectSizeOffsetVisitor 148 : public InstVisitor<ObjectSizeOffsetVisitor, SizeOffsetType> { 149 150 const TargetData *TD; 151 bool RoundToAlign; 152 unsigned IntTyBits; 153 APInt Zero; 154 155 APInt align(APInt Size, uint64_t Align); 156 157 SizeOffsetType unknown() { 158 return std::make_pair(APInt(), APInt()); 159 } 160 161public: 162 ObjectSizeOffsetVisitor(const TargetData *TD, LLVMContext &Context, 163 bool RoundToAlign = false); 164 165 SizeOffsetType compute(Value *V); 166 167 bool knownSize(SizeOffsetType &SizeOffset) { 168 return SizeOffset.first.getBitWidth() > 1; 169 } 170 171 bool knownOffset(SizeOffsetType &SizeOffset) { 172 return SizeOffset.second.getBitWidth() > 1; 173 } 174 175 bool bothKnown(SizeOffsetType &SizeOffset) { 176 return knownSize(SizeOffset) && knownOffset(SizeOffset); 177 } 178 179 SizeOffsetType visitAllocaInst(AllocaInst &I); 180 SizeOffsetType visitArgument(Argument &A); 181 SizeOffsetType visitCallSite(CallSite CS); 182 SizeOffsetType visitConstantPointerNull(ConstantPointerNull&); 183 SizeOffsetType visitExtractValueInst(ExtractValueInst &I); 184 SizeOffsetType visitGEPOperator(GEPOperator &GEP); 185 SizeOffsetType visitGlobalVariable(GlobalVariable &GV); 186 SizeOffsetType visitIntToPtrInst(IntToPtrInst&); 187 SizeOffsetType visitLoadInst(LoadInst &I); 188 SizeOffsetType visitPHINode(PHINode&); 189 SizeOffsetType visitSelectInst(SelectInst &I); 190 SizeOffsetType visitUndefValue(UndefValue&); 191 SizeOffsetType visitInstruction(Instruction &I); 192}; 193 194typedef std::pair<Value*, Value*> SizeOffsetEvalType; 195 196 197/// \brief Evaluate the size and offset of an object ponted by a Value*. 198/// May create code to compute the result at run-time. 199class ObjectSizeOffsetEvaluator 200 : public InstVisitor<ObjectSizeOffsetEvaluator, SizeOffsetEvalType> { 201 202 typedef IRBuilder<true, TargetFolder> BuilderTy; 203 typedef DenseMap<const Value*, SizeOffsetEvalType> CacheMapTy; 204 typedef SmallPtrSet<const Value*, 8> PtrSetTy; 205 206 const TargetData *TD; 207 LLVMContext &Context; 208 BuilderTy Builder; 209 ObjectSizeOffsetVisitor Visitor; 210 IntegerType *IntTy; 211 Value *Zero; 212 CacheMapTy CacheMap; 213 PtrSetTy SeenVals; 214 215 SizeOffsetEvalType unknown() { 216 return std::make_pair((Value*)0, (Value*)0); 217 } 218 SizeOffsetEvalType compute_(Value *V); 219 220public: 221 ObjectSizeOffsetEvaluator(const TargetData *TD, LLVMContext &Context); 222 SizeOffsetEvalType compute(Value *V); 223 224 bool knownSize(SizeOffsetEvalType &SizeOffset) { 225 return SizeOffset.first; 226 } 227 228 bool knownOffset(SizeOffsetEvalType &SizeOffset) { 229 return SizeOffset.second; 230 } 231 232 bool anyKnown(SizeOffsetEvalType &SizeOffset) { 233 return knownSize(SizeOffset) || knownOffset(SizeOffset); 234 } 235 236 bool bothKnown(SizeOffsetEvalType &SizeOffset) { 237 return knownSize(SizeOffset) && knownOffset(SizeOffset); 238 } 239 240 SizeOffsetEvalType visitAllocaInst(AllocaInst &I); 241 SizeOffsetEvalType visitCallSite(CallSite CS); 242 SizeOffsetEvalType visitGEPOperator(GEPOperator &GEP); 243 SizeOffsetEvalType visitIntToPtrInst(IntToPtrInst&); 244 SizeOffsetEvalType visitLoadInst(LoadInst &I); 245 SizeOffsetEvalType visitPHINode(PHINode &PHI); 246 SizeOffsetEvalType visitSelectInst(SelectInst &I); 247 SizeOffsetEvalType visitInstruction(Instruction &I); 248}; 249 250} // End llvm namespace 251 252#endif 253