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);
extractMallocCall(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);
extractCallocCall(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
isFreeCall(Value * I,const TargetLibraryInfo * TLI)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 /// \brief Compute the size of the underlying object pointed by Ptr. Returns
150 /// true and the object size in Size if successful, and false otherwise.
151 /// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
152 /// byval arguments, and global variables.
153 bool getUnderlyingObjectSize(const Value *Ptr, uint64_t &Size,
154 const DataLayout *TD, const TargetLibraryInfo *TLI,
155 bool RoundToAlign = false);
156
157
158
159 typedef std::pair<APInt, APInt> SizeOffsetType;
160
161 /// \brief Evaluate the size and offset of an object ponted by a Value*
162 /// statically. Fails if size or offset are not known at compile time.
163 class ObjectSizeOffsetVisitor
164 : public InstVisitor<ObjectSizeOffsetVisitor, SizeOffsetType> {
165
166 typedef DenseMap<const Value*, SizeOffsetType> CacheMapTy;
167
168 const DataLayout *TD;
169 const TargetLibraryInfo *TLI;
170 bool RoundToAlign;
171 unsigned IntTyBits;
172 APInt Zero;
173 CacheMapTy CacheMap;
174
175 APInt align(APInt Size, uint64_t Align);
176
unknown()177 SizeOffsetType unknown() {
178 return std::make_pair(APInt(), APInt());
179 }
180
181 public:
182 ObjectSizeOffsetVisitor(const DataLayout *TD, const TargetLibraryInfo *TLI,
183 LLVMContext &Context, bool RoundToAlign = false);
184
185 SizeOffsetType compute(Value *V);
186
knownSize(SizeOffsetType & SizeOffset)187 bool knownSize(SizeOffsetType &SizeOffset) {
188 return SizeOffset.first.getBitWidth() > 1;
189 }
190
knownOffset(SizeOffsetType & SizeOffset)191 bool knownOffset(SizeOffsetType &SizeOffset) {
192 return SizeOffset.second.getBitWidth() > 1;
193 }
194
bothKnown(SizeOffsetType & SizeOffset)195 bool bothKnown(SizeOffsetType &SizeOffset) {
196 return knownSize(SizeOffset) && knownOffset(SizeOffset);
197 }
198
199 SizeOffsetType visitAllocaInst(AllocaInst &I);
200 SizeOffsetType visitArgument(Argument &A);
201 SizeOffsetType visitCallSite(CallSite CS);
202 SizeOffsetType visitConstantPointerNull(ConstantPointerNull&);
203 SizeOffsetType visitExtractElementInst(ExtractElementInst &I);
204 SizeOffsetType visitExtractValueInst(ExtractValueInst &I);
205 SizeOffsetType visitGEPOperator(GEPOperator &GEP);
206 SizeOffsetType visitGlobalAlias(GlobalAlias &GA);
207 SizeOffsetType visitGlobalVariable(GlobalVariable &GV);
208 SizeOffsetType visitIntToPtrInst(IntToPtrInst&);
209 SizeOffsetType visitLoadInst(LoadInst &I);
210 SizeOffsetType visitPHINode(PHINode&);
211 SizeOffsetType visitSelectInst(SelectInst &I);
212 SizeOffsetType visitUndefValue(UndefValue&);
213 SizeOffsetType visitInstruction(Instruction &I);
214 };
215
216 typedef std::pair<Value*, Value*> SizeOffsetEvalType;
217
218
219 /// \brief Evaluate the size and offset of an object ponted by a Value*.
220 /// May create code to compute the result at run-time.
221 class ObjectSizeOffsetEvaluator
222 : public InstVisitor<ObjectSizeOffsetEvaluator, SizeOffsetEvalType> {
223
224 typedef IRBuilder<true, TargetFolder> BuilderTy;
225 typedef std::pair<WeakVH, WeakVH> WeakEvalType;
226 typedef DenseMap<const Value*, WeakEvalType> CacheMapTy;
227 typedef SmallPtrSet<const Value*, 8> PtrSetTy;
228
229 const DataLayout *TD;
230 const TargetLibraryInfo *TLI;
231 LLVMContext &Context;
232 BuilderTy Builder;
233 IntegerType *IntTy;
234 Value *Zero;
235 CacheMapTy CacheMap;
236 PtrSetTy SeenVals;
237
unknown()238 SizeOffsetEvalType unknown() {
239 return std::make_pair((Value*)0, (Value*)0);
240 }
241 SizeOffsetEvalType compute_(Value *V);
242
243 public:
244 ObjectSizeOffsetEvaluator(const DataLayout *TD, const TargetLibraryInfo *TLI,
245 LLVMContext &Context);
246 SizeOffsetEvalType compute(Value *V);
247
knownSize(SizeOffsetEvalType SizeOffset)248 bool knownSize(SizeOffsetEvalType SizeOffset) {
249 return SizeOffset.first;
250 }
251
knownOffset(SizeOffsetEvalType SizeOffset)252 bool knownOffset(SizeOffsetEvalType SizeOffset) {
253 return SizeOffset.second;
254 }
255
anyKnown(SizeOffsetEvalType SizeOffset)256 bool anyKnown(SizeOffsetEvalType SizeOffset) {
257 return knownSize(SizeOffset) || knownOffset(SizeOffset);
258 }
259
bothKnown(SizeOffsetEvalType SizeOffset)260 bool bothKnown(SizeOffsetEvalType SizeOffset) {
261 return knownSize(SizeOffset) && knownOffset(SizeOffset);
262 }
263
264 SizeOffsetEvalType visitAllocaInst(AllocaInst &I);
265 SizeOffsetEvalType visitCallSite(CallSite CS);
266 SizeOffsetEvalType visitExtractElementInst(ExtractElementInst &I);
267 SizeOffsetEvalType visitExtractValueInst(ExtractValueInst &I);
268 SizeOffsetEvalType visitGEPOperator(GEPOperator &GEP);
269 SizeOffsetEvalType visitIntToPtrInst(IntToPtrInst&);
270 SizeOffsetEvalType visitLoadInst(LoadInst &I);
271 SizeOffsetEvalType visitPHINode(PHINode &PHI);
272 SizeOffsetEvalType visitSelectInst(SelectInst &I);
273 SizeOffsetEvalType visitInstruction(Instruction &I);
274 };
275
276 } // End llvm namespace
277
278 #endif
279