1 //===- llvm/Analysis/MemoryBuiltins.h- Calls to memory builtins -*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This family of functions identifies calls to builtin functions that allocate
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_MEMORYBUILTINS_H
16 #define LLVM_ANALYSIS_MEMORYBUILTINS_H
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SmallPtrSet.h"
20 #include "llvm/Analysis/TargetFolder.h"
21 #include "llvm/IR/IRBuilder.h"
22 #include "llvm/IR/InstVisitor.h"
23 #include "llvm/IR/Operator.h"
24 #include "llvm/IR/ValueHandle.h"
25 #include "llvm/Support/DataTypes.h"
31 class TargetLibraryInfo;
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
39 bool isAllocationFn(const Value *V, const TargetLibraryInfo *TLI,
40 bool LookThroughBitCast = false);
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);
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);
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);
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);
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);
67 /// \brief Tests if a value is a call or invoke to a library function that
68 /// allocates memory and never returns null (such as operator new).
69 bool isOperatorNewLikeFn(const Value *V, const TargetLibraryInfo *TLI,
70 bool LookThroughBitCast = false);
72 //===----------------------------------------------------------------------===//
73 // malloc Call Utility Functions.
76 /// extractMallocCall - Returns the corresponding CallInst if the instruction
77 /// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
78 /// ignore InvokeInst here.
79 const CallInst *extractMallocCall(const Value *I, const TargetLibraryInfo *TLI);
80 static inline CallInst *extractMallocCall(Value *I,
81 const TargetLibraryInfo *TLI) {
82 return const_cast<CallInst*>(extractMallocCall((const Value*)I, TLI));
85 /// getMallocType - Returns the PointerType resulting from the malloc call.
86 /// The PointerType depends on the number of bitcast uses of the malloc call:
87 /// 0: PointerType is the malloc calls' return type.
88 /// 1: PointerType is the bitcast's result type.
89 /// >1: Unique PointerType cannot be determined, return NULL.
90 PointerType *getMallocType(const CallInst *CI, const TargetLibraryInfo *TLI);
92 /// getMallocAllocatedType - Returns the Type allocated by malloc call.
93 /// The Type depends on the number of bitcast uses of the malloc call:
94 /// 0: PointerType is the malloc calls' return type.
95 /// 1: PointerType is the bitcast's result type.
96 /// >1: Unique PointerType cannot be determined, return NULL.
97 Type *getMallocAllocatedType(const CallInst *CI, const TargetLibraryInfo *TLI);
99 /// getMallocArraySize - Returns the array size of a malloc call. If the
100 /// argument passed to malloc is a multiple of the size of the malloced type,
101 /// then return that multiple. For non-array mallocs, the multiple is
102 /// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
104 Value *getMallocArraySize(CallInst *CI, const DataLayout *DL,
105 const TargetLibraryInfo *TLI,
106 bool LookThroughSExt = false);
109 //===----------------------------------------------------------------------===//
110 // calloc Call Utility Functions.
113 /// extractCallocCall - Returns the corresponding CallInst if the instruction
114 /// is a calloc call.
115 const CallInst *extractCallocCall(const Value *I, const TargetLibraryInfo *TLI);
116 static inline CallInst *extractCallocCall(Value *I,
117 const TargetLibraryInfo *TLI) {
118 return const_cast<CallInst*>(extractCallocCall((const Value*)I, TLI));
122 //===----------------------------------------------------------------------===//
123 // free Call Utility Functions.
126 /// isFreeCall - Returns non-null if the value is a call to the builtin free()
127 const CallInst *isFreeCall(const Value *I, const TargetLibraryInfo *TLI);
129 static inline CallInst *isFreeCall(Value *I, const TargetLibraryInfo *TLI) {
130 return const_cast<CallInst*>(isFreeCall((const Value*)I, TLI));
134 //===----------------------------------------------------------------------===//
135 // Utility functions to compute size of objects.
138 /// \brief Compute the size of the object pointed by Ptr. Returns true and the
139 /// object size in Size if successful, and false otherwise. In this context, by
140 /// object we mean the region of memory starting at Ptr to the end of the
141 /// underlying object pointed to by Ptr.
142 /// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
143 /// byval arguments, and global variables.
144 bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout *DL,
145 const TargetLibraryInfo *TLI, bool RoundToAlign = false);
149 typedef std::pair<APInt, APInt> SizeOffsetType;
151 /// \brief Evaluate the size and offset of an object pointed to by a Value*
152 /// statically. Fails if size or offset are not known at compile time.
153 class ObjectSizeOffsetVisitor
154 : public InstVisitor<ObjectSizeOffsetVisitor, SizeOffsetType> {
156 const DataLayout *DL;
157 const TargetLibraryInfo *TLI;
161 SmallPtrSet<Instruction *, 8> SeenInsts;
163 APInt align(APInt Size, uint64_t Align);
165 SizeOffsetType unknown() {
166 return std::make_pair(APInt(), APInt());
170 ObjectSizeOffsetVisitor(const DataLayout *DL, const TargetLibraryInfo *TLI,
171 LLVMContext &Context, bool RoundToAlign = false);
173 SizeOffsetType compute(Value *V);
175 bool knownSize(SizeOffsetType &SizeOffset) {
176 return SizeOffset.first.getBitWidth() > 1;
179 bool knownOffset(SizeOffsetType &SizeOffset) {
180 return SizeOffset.second.getBitWidth() > 1;
183 bool bothKnown(SizeOffsetType &SizeOffset) {
184 return knownSize(SizeOffset) && knownOffset(SizeOffset);
187 // These are "private", except they can't actually be made private. Only
188 // compute() should be used by external users.
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);
206 typedef std::pair<Value*, Value*> SizeOffsetEvalType;
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> {
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;
219 const DataLayout *DL;
220 const TargetLibraryInfo *TLI;
221 LLVMContext &Context;
229 SizeOffsetEvalType unknown() {
230 return std::make_pair(nullptr, nullptr);
232 SizeOffsetEvalType compute_(Value *V);
235 ObjectSizeOffsetEvaluator(const DataLayout *DL, const TargetLibraryInfo *TLI,
236 LLVMContext &Context, bool RoundToAlign = false);
237 SizeOffsetEvalType compute(Value *V);
239 bool knownSize(SizeOffsetEvalType SizeOffset) {
240 return SizeOffset.first;
243 bool knownOffset(SizeOffsetEvalType SizeOffset) {
244 return SizeOffset.second;
247 bool anyKnown(SizeOffsetEvalType SizeOffset) {
248 return knownSize(SizeOffset) || knownOffset(SizeOffset);
251 bool bothKnown(SizeOffsetEvalType SizeOffset) {
252 return knownSize(SizeOffset) && knownOffset(SizeOffset);
255 // The individual instruction visitors should be treated as private.
256 SizeOffsetEvalType visitAllocaInst(AllocaInst &I);
257 SizeOffsetEvalType visitCallSite(CallSite CS);
258 SizeOffsetEvalType visitExtractElementInst(ExtractElementInst &I);
259 SizeOffsetEvalType visitExtractValueInst(ExtractValueInst &I);
260 SizeOffsetEvalType visitGEPOperator(GEPOperator &GEP);
261 SizeOffsetEvalType visitIntToPtrInst(IntToPtrInst&);
262 SizeOffsetEvalType visitLoadInst(LoadInst &I);
263 SizeOffsetEvalType visitPHINode(PHINode &PHI);
264 SizeOffsetEvalType visitSelectInst(SelectInst &I);
265 SizeOffsetEvalType visitInstruction(Instruction &I);
268 } // End llvm namespace