Line data Source code
1 : //===- MemoryBuiltins.cpp - Identify calls to memory builtins -------------===//
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 : #include "llvm/Analysis/MemoryBuiltins.h"
16 : #include "llvm/ADT/APInt.h"
17 : #include "llvm/ADT/None.h"
18 : #include "llvm/ADT/Optional.h"
19 : #include "llvm/ADT/STLExtras.h"
20 : #include "llvm/ADT/Statistic.h"
21 : #include "llvm/ADT/StringRef.h"
22 : #include "llvm/Analysis/TargetFolder.h"
23 : #include "llvm/Analysis/TargetLibraryInfo.h"
24 : #include "llvm/Analysis/Utils/Local.h"
25 : #include "llvm/Analysis/ValueTracking.h"
26 : #include "llvm/IR/Argument.h"
27 : #include "llvm/IR/Attributes.h"
28 : #include "llvm/IR/Constants.h"
29 : #include "llvm/IR/DataLayout.h"
30 : #include "llvm/IR/DerivedTypes.h"
31 : #include "llvm/IR/Function.h"
32 : #include "llvm/IR/GlobalAlias.h"
33 : #include "llvm/IR/GlobalVariable.h"
34 : #include "llvm/IR/Instruction.h"
35 : #include "llvm/IR/Instructions.h"
36 : #include "llvm/IR/IntrinsicInst.h"
37 : #include "llvm/IR/Operator.h"
38 : #include "llvm/IR/Type.h"
39 : #include "llvm/IR/Value.h"
40 : #include "llvm/Support/Casting.h"
41 : #include "llvm/Support/Debug.h"
42 : #include "llvm/Support/MathExtras.h"
43 : #include "llvm/Support/raw_ostream.h"
44 : #include <cassert>
45 : #include <cstdint>
46 : #include <iterator>
47 : #include <utility>
48 :
49 : using namespace llvm;
50 :
51 : #define DEBUG_TYPE "memory-builtins"
52 :
53 : enum AllocType : uint8_t {
54 : OpNewLike = 1<<0, // allocates; never returns null
55 : MallocLike = 1<<1 | OpNewLike, // allocates; may return null
56 : CallocLike = 1<<2, // allocates + bzero
57 : ReallocLike = 1<<3, // reallocates
58 : StrDupLike = 1<<4,
59 : MallocOrCallocLike = MallocLike | CallocLike,
60 : AllocLike = MallocLike | CallocLike | StrDupLike,
61 : AnyAlloc = AllocLike | ReallocLike
62 : };
63 :
64 : struct AllocFnsTy {
65 : AllocType AllocTy;
66 : unsigned NumParams;
67 : // First and Second size parameters (or -1 if unused)
68 : int FstParam, SndParam;
69 : };
70 :
71 : // FIXME: certain users need more information. E.g., SimplifyLibCalls needs to
72 : // know which functions are nounwind, noalias, nocapture parameters, etc.
73 : static const std::pair<LibFunc, AllocFnsTy> AllocationFnData[] = {
74 : {LibFunc_malloc, {MallocLike, 1, 0, -1}},
75 : {LibFunc_valloc, {MallocLike, 1, 0, -1}},
76 : {LibFunc_Znwj, {OpNewLike, 1, 0, -1}}, // new(unsigned int)
77 : {LibFunc_ZnwjRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new(unsigned int, nothrow)
78 : {LibFunc_ZnwjSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new(unsigned int, align_val_t)
79 : {LibFunc_ZnwjSt11align_val_tRKSt9nothrow_t, // new(unsigned int, align_val_t, nothrow)
80 : {MallocLike, 3, 0, -1}},
81 : {LibFunc_Znwm, {OpNewLike, 1, 0, -1}}, // new(unsigned long)
82 : {LibFunc_ZnwmRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new(unsigned long, nothrow)
83 : {LibFunc_ZnwmSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new(unsigned long, align_val_t)
84 : {LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t, // new(unsigned long, align_val_t, nothrow)
85 : {MallocLike, 3, 0, -1}},
86 : {LibFunc_Znaj, {OpNewLike, 1, 0, -1}}, // new[](unsigned int)
87 : {LibFunc_ZnajRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new[](unsigned int, nothrow)
88 : {LibFunc_ZnajSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new[](unsigned int, align_val_t)
89 : {LibFunc_ZnajSt11align_val_tRKSt9nothrow_t, // new[](unsigned int, align_val_t, nothrow)
90 : {MallocLike, 3, 0, -1}},
91 : {LibFunc_Znam, {OpNewLike, 1, 0, -1}}, // new[](unsigned long)
92 : {LibFunc_ZnamRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new[](unsigned long, nothrow)
93 : {LibFunc_ZnamSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new[](unsigned long, align_val_t)
94 : {LibFunc_ZnamSt11align_val_tRKSt9nothrow_t, // new[](unsigned long, align_val_t, nothrow)
95 : {MallocLike, 3, 0, -1}},
96 : {LibFunc_msvc_new_int, {OpNewLike, 1, 0, -1}}, // new(unsigned int)
97 : {LibFunc_msvc_new_int_nothrow, {MallocLike, 2, 0, -1}}, // new(unsigned int, nothrow)
98 : {LibFunc_msvc_new_longlong, {OpNewLike, 1, 0, -1}}, // new(unsigned long long)
99 : {LibFunc_msvc_new_longlong_nothrow, {MallocLike, 2, 0, -1}}, // new(unsigned long long, nothrow)
100 : {LibFunc_msvc_new_array_int, {OpNewLike, 1, 0, -1}}, // new[](unsigned int)
101 : {LibFunc_msvc_new_array_int_nothrow, {MallocLike, 2, 0, -1}}, // new[](unsigned int, nothrow)
102 : {LibFunc_msvc_new_array_longlong, {OpNewLike, 1, 0, -1}}, // new[](unsigned long long)
103 : {LibFunc_msvc_new_array_longlong_nothrow, {MallocLike, 2, 0, -1}}, // new[](unsigned long long, nothrow)
104 : {LibFunc_calloc, {CallocLike, 2, 0, 1}},
105 : {LibFunc_realloc, {ReallocLike, 2, 1, -1}},
106 : {LibFunc_reallocf, {ReallocLike, 2, 1, -1}},
107 : {LibFunc_strdup, {StrDupLike, 1, -1, -1}},
108 : {LibFunc_strndup, {StrDupLike, 2, 1, -1}}
109 : // TODO: Handle "int posix_memalign(void **, size_t, size_t)"
110 : };
111 :
112 76499573 : static const Function *getCalledFunction(const Value *V, bool LookThroughBitCast,
113 : bool &IsNoBuiltin) {
114 : // Don't care about intrinsics in this case.
115 : if (isa<IntrinsicInst>(V))
116 : return nullptr;
117 :
118 67416310 : if (LookThroughBitCast)
119 0 : V = V->stripPointerCasts();
120 :
121 : ImmutableCallSite CS(V);
122 67416310 : if (!CS.getInstruction())
123 : return nullptr;
124 :
125 13775420 : IsNoBuiltin = CS.isNoBuiltin();
126 :
127 : if (const Function *Callee = CS.getCalledFunction())
128 13036450 : return Callee;
129 : return nullptr;
130 : }
131 :
132 : /// Returns the allocation data for the given value if it's either a call to a
133 : /// known allocation function, or a call to a function with the allocsize
134 : /// attribute.
135 : static Optional<AllocFnsTy>
136 8045241 : getAllocationDataForFunction(const Function *Callee, AllocType AllocTy,
137 : const TargetLibraryInfo *TLI) {
138 : // Make sure that the function is available.
139 8045241 : StringRef FnName = Callee->getName();
140 : LibFunc TLIFn;
141 8045241 : if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
142 : return None;
143 :
144 : const auto *Iter = find_if(
145 : AllocationFnData, [TLIFn](const std::pair<LibFunc, AllocFnsTy> &P) {
146 : return P.first == TLIFn;
147 : });
148 :
149 270052 : if (Iter == std::end(AllocationFnData))
150 : return None;
151 :
152 : const AllocFnsTy *FnData = &Iter->second;
153 94832 : if ((FnData->AllocTy & AllocTy) != FnData->AllocTy)
154 : return None;
155 :
156 : // Check function prototype.
157 86287 : int FstParam = FnData->FstParam;
158 86287 : int SndParam = FnData->SndParam;
159 : FunctionType *FTy = Callee->getFunctionType();
160 :
161 172574 : if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
162 172570 : FTy->getNumParams() == FnData->NumParams &&
163 86124 : (FstParam < 0 ||
164 235514 : (FTy->getParamType(FstParam)->isIntegerTy(32) ||
165 299087 : FTy->getParamType(FstParam)->isIntegerTy(64))) &&
166 368 : (SndParam < 0 ||
167 1093 : FTy->getParamType(SndParam)->isIntegerTy(32) ||
168 714 : FTy->getParamType(SndParam)->isIntegerTy(64)))
169 : return *FnData;
170 : return None;
171 : }
172 :
173 49930064 : static Optional<AllocFnsTy> getAllocationData(const Value *V, AllocType AllocTy,
174 : const TargetLibraryInfo *TLI,
175 : bool LookThroughBitCast = false) {
176 : bool IsNoBuiltinCall;
177 49930064 : if (const Function *Callee =
178 49930064 : getCalledFunction(V, LookThroughBitCast, IsNoBuiltinCall))
179 8106767 : if (!IsNoBuiltinCall)
180 8026287 : return getAllocationDataForFunction(Callee, AllocTy, TLI);
181 : return None;
182 : }
183 :
184 24728 : static Optional<AllocFnsTy> getAllocationSize(const Value *V,
185 : const TargetLibraryInfo *TLI) {
186 : bool IsNoBuiltinCall;
187 : const Function *Callee =
188 24728 : getCalledFunction(V, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
189 24728 : if (!Callee)
190 : return None;
191 :
192 : // Prefer to use existing information over allocsize. This will give us an
193 : // accurate AllocTy.
194 24146 : if (!IsNoBuiltinCall)
195 18954 : if (Optional<AllocFnsTy> Data =
196 18954 : getAllocationDataForFunction(Callee, AnyAlloc, TLI))
197 : return Data;
198 :
199 5703 : Attribute Attr = Callee->getFnAttribute(Attribute::AllocSize);
200 5703 : if (Attr == Attribute())
201 : return None;
202 :
203 18 : std::pair<unsigned, Optional<unsigned>> Args = Attr.getAllocSizeArgs();
204 :
205 : AllocFnsTy Result;
206 : // Because allocsize only tells us how many bytes are allocated, we're not
207 : // really allowed to assume anything, so we use MallocLike.
208 : Result.AllocTy = MallocLike;
209 : Result.NumParams = Callee->getNumOperands();
210 18 : Result.FstParam = Args.first;
211 18 : Result.SndParam = Args.second.getValueOr(-1);
212 : return Result;
213 : }
214 :
215 19812323 : static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
216 19812323 : ImmutableCallSite CS(LookThroughBitCast ? V->stripPointerCasts() : V);
217 19812323 : return CS && CS.hasRetAttr(Attribute::NoAlias);
218 : }
219 :
220 : /// Tests if a value is a call or invoke to a library function that
221 : /// allocates or reallocates memory (either malloc, calloc, realloc, or strdup
222 : /// like).
223 19832673 : bool llvm::isAllocationFn(const Value *V, const TargetLibraryInfo *TLI,
224 : bool LookThroughBitCast) {
225 19832673 : return getAllocationData(V, AnyAlloc, TLI, LookThroughBitCast).hasValue();
226 : }
227 :
228 : /// Tests if a value is a call or invoke to a function that returns a
229 : /// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions).
230 19822851 : bool llvm::isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI,
231 : bool LookThroughBitCast) {
232 : // it's safe to consider realloc as noalias since accessing the original
233 : // pointer is undefined behavior
234 39635174 : return isAllocationFn(V, TLI, LookThroughBitCast) ||
235 19812323 : hasNoAliasAttr(V, LookThroughBitCast);
236 : }
237 :
238 : /// Tests if a value is a call or invoke to a library function that
239 : /// allocates uninitialized memory (such as malloc).
240 45561 : bool llvm::isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
241 : bool LookThroughBitCast) {
242 45561 : return getAllocationData(V, MallocLike, TLI, LookThroughBitCast).hasValue();
243 : }
244 :
245 : /// Tests if a value is a call or invoke to a library function that
246 : /// allocates zero-filled memory (such as calloc).
247 57644 : bool llvm::isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
248 : bool LookThroughBitCast) {
249 57644 : return getAllocationData(V, CallocLike, TLI, LookThroughBitCast).hasValue();
250 : }
251 :
252 : /// Tests if a value is a call or invoke to a library function that
253 : /// allocates memory similar to malloc or calloc.
254 5432318 : bool llvm::isMallocOrCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
255 : bool LookThroughBitCast) {
256 5432318 : return getAllocationData(V, MallocOrCallocLike, TLI,
257 10864636 : LookThroughBitCast).hasValue();
258 : }
259 :
260 : /// Tests if a value is a call or invoke to a library function that
261 : /// allocates memory (either malloc, calloc, or strdup like).
262 24561868 : bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
263 : bool LookThroughBitCast) {
264 24561868 : return getAllocationData(V, AllocLike, TLI, LookThroughBitCast).hasValue();
265 : }
266 :
267 : /// extractMallocCall - Returns the corresponding CallInst if the instruction
268 : /// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
269 : /// ignore InvokeInst here.
270 104 : const CallInst *llvm::extractMallocCall(const Value *I,
271 : const TargetLibraryInfo *TLI) {
272 104 : return isMallocLikeFn(I, TLI) ? dyn_cast<CallInst>(I) : nullptr;
273 : }
274 :
275 26 : static Value *computeArraySize(const CallInst *CI, const DataLayout &DL,
276 : const TargetLibraryInfo *TLI,
277 : bool LookThroughSExt = false) {
278 26 : if (!CI)
279 : return nullptr;
280 :
281 : // The size of the malloc's result type must be known to determine array size.
282 26 : Type *T = getMallocAllocatedType(CI, TLI);
283 26 : if (!T || !T->isSized())
284 0 : return nullptr;
285 :
286 26 : unsigned ElementSize = DL.getTypeAllocSize(T);
287 : if (StructType *ST = dyn_cast<StructType>(T))
288 14 : ElementSize = DL.getStructLayout(ST)->getSizeInBytes();
289 :
290 : // If malloc call's arg can be determined to be a multiple of ElementSize,
291 : // return the multiple. Otherwise, return NULL.
292 26 : Value *MallocArg = CI->getArgOperand(0);
293 26 : Value *Multiple = nullptr;
294 26 : if (ComputeMultiple(MallocArg, ElementSize, Multiple, LookThroughSExt))
295 18 : return Multiple;
296 :
297 : return nullptr;
298 : }
299 :
300 : /// getMallocType - Returns the PointerType resulting from the malloc call.
301 : /// The PointerType depends on the number of bitcast uses of the malloc call:
302 : /// 0: PointerType is the calls' return type.
303 : /// 1: PointerType is the bitcast's result type.
304 : /// >1: Unique PointerType cannot be determined, return NULL.
305 97 : PointerType *llvm::getMallocType(const CallInst *CI,
306 : const TargetLibraryInfo *TLI) {
307 : assert(isMallocLikeFn(CI, TLI) && "getMallocType and not malloc call");
308 :
309 : PointerType *MallocType = nullptr;
310 : unsigned NumOfBitCastUses = 0;
311 :
312 : // Determine if CallInst has a bitcast use.
313 : for (Value::const_user_iterator UI = CI->user_begin(), E = CI->user_end();
314 194 : UI != E;)
315 : if (const BitCastInst *BCI = dyn_cast<BitCastInst>(*UI++)) {
316 : MallocType = cast<PointerType>(BCI->getDestTy());
317 97 : NumOfBitCastUses++;
318 : }
319 :
320 : // Malloc call has 1 bitcast use, so type is the bitcast's destination type.
321 97 : if (NumOfBitCastUses == 1)
322 : return MallocType;
323 :
324 : // Malloc call was not bitcast, so type is the malloc function's return type.
325 0 : if (NumOfBitCastUses == 0)
326 0 : return cast<PointerType>(CI->getType());
327 :
328 : // Type could not be determined.
329 : return nullptr;
330 : }
331 :
332 : /// getMallocAllocatedType - Returns the Type allocated by malloc call.
333 : /// The Type depends on the number of bitcast uses of the malloc call:
334 : /// 0: PointerType is the malloc calls' return type.
335 : /// 1: PointerType is the bitcast's result type.
336 : /// >1: Unique PointerType cannot be determined, return NULL.
337 97 : Type *llvm::getMallocAllocatedType(const CallInst *CI,
338 : const TargetLibraryInfo *TLI) {
339 97 : PointerType *PT = getMallocType(CI, TLI);
340 97 : return PT ? PT->getElementType() : nullptr;
341 : }
342 :
343 : /// getMallocArraySize - Returns the array size of a malloc call. If the
344 : /// argument passed to malloc is a multiple of the size of the malloced type,
345 : /// then return that multiple. For non-array mallocs, the multiple is
346 : /// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
347 : /// determined.
348 26 : Value *llvm::getMallocArraySize(CallInst *CI, const DataLayout &DL,
349 : const TargetLibraryInfo *TLI,
350 : bool LookThroughSExt) {
351 : assert(isMallocLikeFn(CI, TLI) && "getMallocArraySize and not malloc call");
352 26 : return computeArraySize(CI, DL, TLI, LookThroughSExt);
353 : }
354 :
355 : /// extractCallocCall - Returns the corresponding CallInst if the instruction
356 : /// is a calloc call.
357 0 : const CallInst *llvm::extractCallocCall(const Value *I,
358 : const TargetLibraryInfo *TLI) {
359 0 : return isCallocLikeFn(I, TLI) ? cast<CallInst>(I) : nullptr;
360 : }
361 :
362 : /// isFreeCall - Returns non-null if the value is a call to the builtin free()
363 26544781 : const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
364 : bool IsNoBuiltinCall;
365 : const Function *Callee =
366 26544781 : getCalledFunction(I, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
367 26544781 : if (Callee == nullptr || IsNoBuiltinCall)
368 : return nullptr;
369 :
370 4844400 : StringRef FnName = Callee->getName();
371 : LibFunc TLIFn;
372 4844400 : if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
373 4661173 : return nullptr;
374 :
375 : unsigned ExpectedNumParams;
376 183227 : if (TLIFn == LibFunc_free ||
377 68975 : TLIFn == LibFunc_ZdlPv || // operator delete(void*)
378 67643 : TLIFn == LibFunc_ZdaPv || // operator delete[](void*)
379 67618 : TLIFn == LibFunc_msvc_delete_ptr32 || // operator delete(void*)
380 67616 : TLIFn == LibFunc_msvc_delete_ptr64 || // operator delete(void*)
381 67616 : TLIFn == LibFunc_msvc_delete_array_ptr32 || // operator delete[](void*)
382 : TLIFn == LibFunc_msvc_delete_array_ptr64) // operator delete[](void*)
383 : ExpectedNumParams = 1;
384 67616 : else if (TLIFn == LibFunc_ZdlPvj || // delete(void*, uint)
385 67603 : TLIFn == LibFunc_ZdlPvm || // delete(void*, ulong)
386 67600 : TLIFn == LibFunc_ZdlPvRKSt9nothrow_t || // delete(void*, nothrow)
387 64490 : TLIFn == LibFunc_ZdlPvSt11align_val_t || // delete(void*, align_val_t)
388 64488 : TLIFn == LibFunc_ZdaPvj || // delete[](void*, uint)
389 64485 : TLIFn == LibFunc_ZdaPvm || // delete[](void*, ulong)
390 64485 : TLIFn == LibFunc_ZdaPvRKSt9nothrow_t || // delete[](void*, nothrow)
391 64357 : TLIFn == LibFunc_ZdaPvSt11align_val_t || // delete[](void*, align_val_t)
392 64357 : TLIFn == LibFunc_msvc_delete_ptr32_int || // delete(void*, uint)
393 64357 : TLIFn == LibFunc_msvc_delete_ptr64_longlong || // delete(void*, ulonglong)
394 64357 : TLIFn == LibFunc_msvc_delete_ptr32_nothrow || // delete(void*, nothrow)
395 64357 : TLIFn == LibFunc_msvc_delete_ptr64_nothrow || // delete(void*, nothrow)
396 64357 : TLIFn == LibFunc_msvc_delete_array_ptr32_int || // delete[](void*, uint)
397 64357 : TLIFn == LibFunc_msvc_delete_array_ptr64_longlong || // delete[](void*, ulonglong)
398 64357 : TLIFn == LibFunc_msvc_delete_array_ptr32_nothrow || // delete[](void*, nothrow)
399 : TLIFn == LibFunc_msvc_delete_array_ptr64_nothrow) // delete[](void*, nothrow)
400 : ExpectedNumParams = 2;
401 64357 : else if (TLIFn == LibFunc_ZdaPvSt11align_val_tRKSt9nothrow_t || // delete(void*, align_val_t, nothrow)
402 : TLIFn == LibFunc_ZdlPvSt11align_val_tRKSt9nothrow_t) // delete[](void*, align_val_t, nothrow)
403 : ExpectedNumParams = 3;
404 : else
405 : return nullptr;
406 :
407 : // Check free prototype.
408 : // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
409 : // attribute will exist.
410 : FunctionType *FTy = Callee->getFunctionType();
411 237764 : if (!FTy->getReturnType()->isVoidTy())
412 : return nullptr;
413 237764 : if (FTy->getNumParams() != ExpectedNumParams)
414 : return nullptr;
415 118881 : if (FTy->getParamType(0) != Type::getInt8PtrTy(Callee->getContext()))
416 : return nullptr;
417 :
418 : return dyn_cast<CallInst>(I);
419 : }
420 :
421 : //===----------------------------------------------------------------------===//
422 : // Utility functions to compute size of objects.
423 : //
424 21786471 : static APInt getSizeWithOverflow(const SizeOffsetType &Data) {
425 21786471 : if (Data.second.isNegative() || Data.first.ult(Data.second))
426 0 : return APInt(Data.first.getBitWidth(), 0);
427 21786471 : return Data.first - Data.second;
428 : }
429 :
430 : /// Compute the size of the object pointed by Ptr. Returns true and the
431 : /// object size in Size if successful, and false otherwise.
432 : /// If RoundToAlign is true, then Size is rounded up to the alignment of
433 : /// allocas, byval arguments, and global variables.
434 22320684 : bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
435 : const TargetLibraryInfo *TLI, ObjectSizeOpts Opts) {
436 44641368 : ObjectSizeOffsetVisitor Visitor(DL, TLI, Ptr->getContext(), Opts);
437 44641368 : SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
438 : if (!Visitor.bothKnown(Data))
439 : return false;
440 :
441 43572926 : Size = getSizeWithOverflow(Data).getZExtValue();
442 21786463 : return true;
443 : }
444 :
445 168 : ConstantInt *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
446 : const DataLayout &DL,
447 : const TargetLibraryInfo *TLI,
448 : bool MustSucceed) {
449 : assert(ObjectSize->getIntrinsicID() == Intrinsic::objectsize &&
450 : "ObjectSize must be a call to llvm.objectsize!");
451 :
452 168 : bool MaxVal = cast<ConstantInt>(ObjectSize->getArgOperand(1))->isZero();
453 168 : ObjectSizeOpts EvalOptions;
454 : // Unless we have to fold this to something, try to be as accurate as
455 : // possible.
456 168 : if (MustSucceed)
457 35 : EvalOptions.EvalMode =
458 35 : MaxVal ? ObjectSizeOpts::Mode::Max : ObjectSizeOpts::Mode::Min;
459 : else
460 : EvalOptions.EvalMode = ObjectSizeOpts::Mode::Exact;
461 :
462 168 : EvalOptions.NullIsUnknownSize =
463 : cast<ConstantInt>(ObjectSize->getArgOperand(2))->isOne();
464 :
465 : // FIXME: Does it make sense to just return a failure value if the size won't
466 : // fit in the output and `!MustSucceed`?
467 : uint64_t Size;
468 168 : auto *ResultType = cast<IntegerType>(ObjectSize->getType());
469 168 : if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, EvalOptions) &&
470 57 : isUIntN(ResultType->getBitWidth(), Size))
471 52 : return ConstantInt::get(ResultType, Size);
472 :
473 116 : if (!MustSucceed)
474 : return nullptr;
475 :
476 28 : return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0);
477 : }
478 :
479 : STATISTIC(ObjectVisitorArgument,
480 : "Number of arguments with unsolved size and offset");
481 : STATISTIC(ObjectVisitorLoad,
482 : "Number of load instructions with unsolved size and offset");
483 :
484 21769891 : APInt ObjectSizeOffsetVisitor::align(APInt Size, uint64_t Align) {
485 21769891 : if (Options.RoundToAlign && Align)
486 1118494 : return APInt(IntTyBits, alignTo(Size.getZExtValue(), Align));
487 : return Size;
488 : }
489 :
490 22321548 : ObjectSizeOffsetVisitor::ObjectSizeOffsetVisitor(const DataLayout &DL,
491 : const TargetLibraryInfo *TLI,
492 : LLVMContext &Context,
493 22321548 : ObjectSizeOpts Options)
494 22321548 : : DL(DL), TLI(TLI), Options(Options) {
495 : // Pointer size must be rechecked for each object visited since it could have
496 : // a different address space.
497 22321548 : }
498 :
499 22322344 : SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
500 22322344 : IntTyBits = DL.getPointerTypeSizeInBits(V->getType());
501 44644688 : Zero = APInt::getNullValue(IntTyBits);
502 :
503 : V = V->stripPointerCasts();
504 : if (Instruction *I = dyn_cast<Instruction>(V)) {
505 : // If we have already seen this instruction, bail out. Cycles can happen in
506 : // unreachable code after constant propagation.
507 1599852 : if (!SeenInsts.insert(I).second)
508 : return unknown();
509 :
510 : if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
511 900 : return visitGEPOperator(*GEP);
512 1598915 : return visit(*I);
513 : }
514 : if (Argument *A = dyn_cast<Argument>(V))
515 37940 : return visitArgument(*A);
516 : if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
517 20 : return visitConstantPointerNull(*P);
518 : if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
519 2 : return visitGlobalAlias(*GA);
520 : if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
521 20684470 : return visitGlobalVariable(*GV);
522 : if (UndefValue *UV = dyn_cast<UndefValue>(V))
523 11 : return visitUndefValue(*UV);
524 : if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
525 12 : if (CE->getOpcode() == Instruction::IntToPtr)
526 : return unknown(); // clueless
527 12 : if (CE->getOpcode() == Instruction::GetElementPtr)
528 12 : return visitGEPOperator(cast<GEPOperator>(*CE));
529 : }
530 :
531 : LLVM_DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: "
532 : << *V << '\n');
533 : return unknown();
534 : }
535 :
536 : /// When we're compiling N-bit code, and the user uses parameters that are
537 : /// greater than N bits (e.g. uint64_t on a 32-bit build), we can run into
538 : /// trouble with APInt size issues. This function handles resizing + overflow
539 : /// checks for us. Check and zext or trunc \p I depending on IntTyBits and
540 : /// I's value.
541 16779 : bool ObjectSizeOffsetVisitor::CheckedZextOrTrunc(APInt &I) {
542 : // More bits than we can handle. Checking the bit width isn't necessary, but
543 : // it's faster than checking active bits, and should give `false` in the
544 : // vast majority of cases.
545 16779 : if (I.getBitWidth() > IntTyBits && I.getActiveBits() > IntTyBits)
546 : return false;
547 16776 : if (I.getBitWidth() != IntTyBits)
548 92 : I = I.zextOrTrunc(IntTyBits);
549 : return true;
550 : }
551 :
552 1562264 : SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
553 1562264 : if (!I.getAllocatedType()->isSized())
554 : return unknown();
555 :
556 1562264 : APInt Size(IntTyBits, DL.getTypeAllocSize(I.getAllocatedType()));
557 1562264 : if (!I.isArrayAllocation())
558 6248592 : return std::make_pair(align(Size, I.getAlignment()), Zero);
559 :
560 : Value *ArraySize = I.getArraySize();
561 : if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
562 : APInt NumElems = C->getValue();
563 58 : if (!CheckedZextOrTrunc(NumElems))
564 : return unknown();
565 :
566 : bool Overflow;
567 57 : Size = Size.umul_ov(NumElems, Overflow);
568 228 : return Overflow ? unknown() : std::make_pair(align(Size, I.getAlignment()),
569 57 : Zero);
570 : }
571 : return unknown();
572 : }
573 :
574 37940 : SizeOffsetType ObjectSizeOffsetVisitor::visitArgument(Argument &A) {
575 : // No interprocedural analysis is done at the moment.
576 37940 : if (!A.hasByValOrInAllocaAttr()) {
577 : ++ObjectVisitorArgument;
578 : return unknown();
579 : }
580 4378 : PointerType *PT = cast<PointerType>(A.getType());
581 4378 : APInt Size(IntTyBits, DL.getTypeAllocSize(PT->getElementType()));
582 13134 : return std::make_pair(align(Size, A.getParamAlignment()), Zero);
583 : }
584 :
585 24722 : SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
586 49444 : Optional<AllocFnsTy> FnData = getAllocationSize(CS.getInstruction(), TLI);
587 24722 : if (!FnData)
588 : return unknown();
589 :
590 : // Handle strdup-like functions separately.
591 18455 : if (FnData->AllocTy == StrDupLike) {
592 5 : APInt Size(IntTyBits, GetStringLength(CS.getArgument(0)));
593 5 : if (!Size)
594 : return unknown();
595 :
596 : // Strndup limits strlen.
597 5 : if (FnData->FstParam > 0) {
598 : ConstantInt *Arg =
599 4 : dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
600 : if (!Arg)
601 0 : return unknown();
602 :
603 4 : APInt MaxSize = Arg->getValue().zextOrSelf(IntTyBits);
604 4 : if (Size.ugt(MaxSize))
605 2 : Size = MaxSize + 1;
606 : }
607 5 : return std::make_pair(Size, Zero);
608 : }
609 :
610 18450 : ConstantInt *Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
611 : if (!Arg)
612 : return unknown();
613 :
614 : APInt Size = Arg->getValue();
615 16713 : if (!CheckedZextOrTrunc(Size))
616 : return unknown();
617 :
618 : // Size is determined by just 1 parameter.
619 16711 : if (FnData->SndParam < 0)
620 16694 : return std::make_pair(Size, Zero);
621 :
622 17 : Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->SndParam));
623 : if (!Arg)
624 : return unknown();
625 :
626 : APInt NumElems = Arg->getValue();
627 8 : if (!CheckedZextOrTrunc(NumElems))
628 : return unknown();
629 :
630 : bool Overflow;
631 8 : Size = Size.umul_ov(NumElems, Overflow);
632 8 : return Overflow ? unknown() : std::make_pair(Size, Zero);
633 :
634 : // TODO: handle more standard functions (+ wchar cousins):
635 : // - strdup / strndup
636 : // - strcpy / strncpy
637 : // - strcat / strncat
638 : // - memcpy / memmove
639 : // - strcat / strncat
640 : // - memset
641 : }
642 :
643 : SizeOffsetType
644 20 : ObjectSizeOffsetVisitor::visitConstantPointerNull(ConstantPointerNull& CPN) {
645 : // If null is unknown, there's nothing we can do. Additionally, non-zero
646 : // address spaces can make use of null, so we don't presume to know anything
647 : // about that.
648 : //
649 : // TODO: How should this work with address space casts? We currently just drop
650 : // them on the floor, but it's unclear what we should do when a NULL from
651 : // addrspace(1) gets casted to addrspace(0) (or vice-versa).
652 20 : if (Options.NullIsUnknownSize || CPN.getType()->getAddressSpace())
653 : return unknown();
654 8 : return std::make_pair(Zero, Zero);
655 : }
656 :
657 : SizeOffsetType
658 0 : ObjectSizeOffsetVisitor::visitExtractElementInst(ExtractElementInst&) {
659 0 : return unknown();
660 : }
661 :
662 : SizeOffsetType
663 0 : ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
664 : // Easy cases were already folded by previous passes.
665 0 : return unknown();
666 : }
667 :
668 912 : SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
669 1824 : SizeOffsetType PtrData = compute(GEP.getPointerOperand());
670 912 : APInt Offset(IntTyBits, 0);
671 59 : if (!bothKnown(PtrData) || !GEP.accumulateConstantOffset(DL, Offset))
672 : return unknown();
673 :
674 40 : return std::make_pair(PtrData.first, PtrData.second + Offset);
675 : }
676 :
677 2 : SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalAlias(GlobalAlias &GA) {
678 : if (GA.isInterposable())
679 : return unknown();
680 0 : return compute(GA.getAliasee());
681 : }
682 :
683 20684470 : SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
684 20684470 : if (!GV.hasDefinitiveInitializer())
685 : return unknown();
686 :
687 40406616 : APInt Size(IntTyBits, DL.getTypeAllocSize(GV.getType()->getElementType()));
688 80813232 : return std::make_pair(align(Size, GV.getAlignment()), Zero);
689 : }
690 :
691 99 : SizeOffsetType ObjectSizeOffsetVisitor::visitIntToPtrInst(IntToPtrInst&) {
692 : // clueless
693 99 : return unknown();
694 : }
695 :
696 1691 : SizeOffsetType ObjectSizeOffsetVisitor::visitLoadInst(LoadInst&) {
697 : ++ObjectVisitorLoad;
698 1691 : return unknown();
699 : }
700 :
701 9867 : SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
702 : // too complex to analyze statically.
703 9867 : return unknown();
704 : }
705 :
706 272 : SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
707 544 : SizeOffsetType TrueSide = compute(I.getTrueValue());
708 544 : SizeOffsetType FalseSide = compute(I.getFalseValue());
709 : if (bothKnown(TrueSide) && bothKnown(FalseSide)) {
710 6 : if (TrueSide == FalseSide) {
711 6 : return TrueSide;
712 : }
713 :
714 4 : APInt TrueResult = getSizeWithOverflow(TrueSide);
715 4 : APInt FalseResult = getSizeWithOverflow(FalseSide);
716 :
717 4 : if (TrueResult == FalseResult) {
718 : return TrueSide;
719 : }
720 3 : if (Options.EvalMode == ObjectSizeOpts::Mode::Min) {
721 1 : if (TrueResult.slt(FalseResult))
722 : return TrueSide;
723 : return FalseSide;
724 : }
725 2 : if (Options.EvalMode == ObjectSizeOpts::Mode::Max) {
726 2 : if (TrueResult.sgt(FalseResult))
727 : return TrueSide;
728 : return FalseSide;
729 : }
730 : }
731 : return unknown();
732 : }
733 :
734 11 : SizeOffsetType ObjectSizeOffsetVisitor::visitUndefValue(UndefValue&) {
735 11 : return std::make_pair(Zero, Zero);
736 : }
737 :
738 0 : SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
739 : LLVM_DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I
740 : << '\n');
741 0 : return unknown();
742 : }
743 :
744 56 : ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(
745 : const DataLayout &DL, const TargetLibraryInfo *TLI, LLVMContext &Context,
746 56 : bool RoundToAlign)
747 : : DL(DL), TLI(TLI), Context(Context), Builder(Context, TargetFolder(DL)),
748 112 : RoundToAlign(RoundToAlign) {
749 : // IntTy and Zero must be set for each compute() since the address space may
750 : // be different for later objects.
751 56 : }
752 :
753 91 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
754 : // XXX - Are vectors of pointers possible here?
755 91 : IntTy = cast<IntegerType>(DL.getIntPtrType(V->getType()));
756 91 : Zero = ConstantInt::get(IntTy, 0);
757 :
758 91 : SizeOffsetEvalType Result = compute_(V);
759 :
760 : if (!bothKnown(Result)) {
761 : // Erase everything that was computed in this iteration from the cache, so
762 : // that no dangling references are left behind. We could be a bit smarter if
763 : // we kept a dependency graph. It's probably not worth the complexity.
764 33 : for (const Value *SeenVal : SeenVals) {
765 20 : CacheMapTy::iterator CacheIt = CacheMap.find(SeenVal);
766 : // non-computable results can be safely cached
767 20 : if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
768 : CacheMap.erase(CacheIt);
769 : }
770 : }
771 :
772 91 : SeenVals.clear();
773 91 : return Result;
774 : }
775 :
776 142 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
777 142 : ObjectSizeOpts ObjSizeOptions;
778 142 : ObjSizeOptions.RoundToAlign = RoundToAlign;
779 :
780 284 : ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, ObjSizeOptions);
781 284 : SizeOffsetType Const = Visitor.compute(V);
782 : if (Visitor.bothKnown(Const))
783 62 : return std::make_pair(ConstantInt::get(Context, Const.first),
784 124 : ConstantInt::get(Context, Const.second));
785 :
786 : V = V->stripPointerCasts();
787 :
788 : // Check cache.
789 80 : CacheMapTy::iterator CacheIt = CacheMap.find(V);
790 80 : if (CacheIt != CacheMap.end())
791 12 : return CacheIt->second;
792 :
793 : // Always generate code immediately before the instruction being
794 : // processed, so that the generated code dominates the same BBs.
795 68 : BuilderTy::InsertPointGuard Guard(Builder);
796 : if (Instruction *I = dyn_cast<Instruction>(V))
797 63 : Builder.SetInsertPoint(I);
798 :
799 : // Now compute the size and offset.
800 : SizeOffsetEvalType Result;
801 :
802 : // Record the pointers that were handled in this run, so that they can be
803 : // cleaned later if something fails. We also use this set to break cycles that
804 : // can occur in dead code.
805 68 : if (!SeenVals.insert(V).second) {
806 : Result = unknown();
807 : } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
808 35 : Result = visitGEPOperator(*GEP);
809 : } else if (Instruction *I = dyn_cast<Instruction>(V)) {
810 26 : Result = visit(*I);
811 1 : } else if (isa<Argument>(V) ||
812 : (isa<ConstantExpr>(V) &&
813 : cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
814 5 : isa<GlobalAlias>(V) ||
815 : isa<GlobalVariable>(V)) {
816 : // Ignore values where we cannot do more than ObjectSizeVisitor.
817 : Result = unknown();
818 : } else {
819 : LLVM_DEBUG(
820 : dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: " << *V
821 : << '\n');
822 : Result = unknown();
823 : }
824 :
825 : // Don't reuse CacheIt since it may be invalid at this point.
826 68 : CacheMap[V] = Result;
827 68 : return Result;
828 : }
829 :
830 10 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
831 10 : if (!I.getAllocatedType()->isSized())
832 : return unknown();
833 :
834 : // must be a VLA
835 : assert(I.isArrayAllocation());
836 : Value *ArraySize = I.getArraySize();
837 10 : Value *Size = ConstantInt::get(ArraySize->getType(),
838 10 : DL.getTypeAllocSize(I.getAllocatedType()));
839 20 : Size = Builder.CreateMul(Size, ArraySize);
840 10 : return std::make_pair(Size, Zero);
841 : }
842 :
843 6 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
844 12 : Optional<AllocFnsTy> FnData = getAllocationSize(CS.getInstruction(), TLI);
845 6 : if (!FnData)
846 : return unknown();
847 :
848 : // Handle strdup-like functions separately.
849 6 : if (FnData->AllocTy == StrDupLike) {
850 : // TODO
851 : return unknown();
852 : }
853 :
854 6 : Value *FirstArg = CS.getArgument(FnData->FstParam);
855 12 : FirstArg = Builder.CreateZExt(FirstArg, IntTy);
856 6 : if (FnData->SndParam < 0)
857 2 : return std::make_pair(FirstArg, Zero);
858 :
859 4 : Value *SecondArg = CS.getArgument(FnData->SndParam);
860 4 : SecondArg = Builder.CreateZExt(SecondArg, IntTy);
861 4 : Value *Size = Builder.CreateMul(FirstArg, SecondArg);
862 4 : return std::make_pair(Size, Zero);
863 :
864 : // TODO: handle more standard functions (+ wchar cousins):
865 : // - strdup / strndup
866 : // - strcpy / strncpy
867 : // - strcat / strncat
868 : // - memcpy / memmove
869 : // - strcat / strncat
870 : // - memset
871 : }
872 :
873 : SizeOffsetEvalType
874 0 : ObjectSizeOffsetEvaluator::visitExtractElementInst(ExtractElementInst&) {
875 0 : return unknown();
876 : }
877 :
878 : SizeOffsetEvalType
879 0 : ObjectSizeOffsetEvaluator::visitExtractValueInst(ExtractValueInst&) {
880 0 : return unknown();
881 : }
882 :
883 : SizeOffsetEvalType
884 35 : ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
885 35 : SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
886 : if (!bothKnown(PtrData))
887 : return unknown();
888 :
889 28 : Value *Offset = EmitGEPOffset(&Builder, DL, &GEP, /*NoAssumptions=*/true);
890 28 : Offset = Builder.CreateAdd(PtrData.second, Offset);
891 : return std::make_pair(PtrData.first, Offset);
892 : }
893 :
894 0 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitIntToPtrInst(IntToPtrInst&) {
895 : // clueless
896 0 : return unknown();
897 : }
898 :
899 2 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitLoadInst(LoadInst&) {
900 2 : return unknown();
901 : }
902 :
903 4 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
904 : // Create 2 PHIs: one for size and another for offset.
905 8 : PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
906 4 : PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
907 :
908 : // Insert right away in the cache to handle recursive PHIs.
909 8 : CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
910 :
911 : // Compute offset/size for each PHI incoming pointer.
912 10 : for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
913 16 : Builder.SetInsertPoint(&*PHI.getIncomingBlock(i)->getFirstInsertionPt());
914 8 : SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
915 :
916 : if (!bothKnown(EdgeData)) {
917 2 : OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
918 2 : OffsetPHI->eraseFromParent();
919 2 : SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
920 2 : SizePHI->eraseFromParent();
921 : return unknown();
922 : }
923 6 : SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
924 6 : OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
925 : }
926 :
927 : Value *Size = SizePHI, *Offset = OffsetPHI, *Tmp;
928 2 : if ((Tmp = SizePHI->hasConstantValue())) {
929 : Size = Tmp;
930 2 : SizePHI->replaceAllUsesWith(Size);
931 2 : SizePHI->eraseFromParent();
932 : }
933 2 : if ((Tmp = OffsetPHI->hasConstantValue())) {
934 : Offset = Tmp;
935 0 : OffsetPHI->replaceAllUsesWith(Offset);
936 0 : OffsetPHI->eraseFromParent();
937 : }
938 : return std::make_pair(Size, Offset);
939 : }
940 :
941 4 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
942 4 : SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
943 4 : SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
944 :
945 : if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
946 : return unknown();
947 : if (TrueSide == FalseSide)
948 0 : return TrueSide;
949 :
950 4 : Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
951 : FalseSide.first);
952 2 : Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
953 : FalseSide.second);
954 : return std::make_pair(Size, Offset);
955 : }
956 :
957 0 : SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitInstruction(Instruction &I) {
958 : LLVM_DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I
959 : << '\n');
960 0 : return unknown();
961 : }
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