LLVM  9.0.0svn
MemoryBuiltins.cpp
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1 //===- MemoryBuiltins.cpp - Identify calls to memory builtins -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This family of functions identifies calls to builtin functions that allocate
10 // or free memory.
11 //
12 //===----------------------------------------------------------------------===//
13 
15 #include "llvm/ADT/APInt.h"
16 #include "llvm/ADT/None.h"
17 #include "llvm/ADT/Optional.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/ADT/StringRef.h"
25 #include "llvm/IR/Argument.h"
26 #include "llvm/IR/Attributes.h"
27 #include "llvm/IR/Constants.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/DerivedTypes.h"
30 #include "llvm/IR/Function.h"
31 #include "llvm/IR/GlobalAlias.h"
32 #include "llvm/IR/GlobalVariable.h"
33 #include "llvm/IR/Instruction.h"
34 #include "llvm/IR/Instructions.h"
35 #include "llvm/IR/IntrinsicInst.h"
36 #include "llvm/IR/Operator.h"
37 #include "llvm/IR/Type.h"
38 #include "llvm/IR/Value.h"
39 #include "llvm/Support/Casting.h"
40 #include "llvm/Support/Debug.h"
43 #include <cassert>
44 #include <cstdint>
45 #include <iterator>
46 #include <utility>
47 
48 using namespace llvm;
49 
50 #define DEBUG_TYPE "memory-builtins"
51 
52 enum AllocType : uint8_t {
53  OpNewLike = 1<<0, // allocates; never returns null
54  MallocLike = 1<<1 | OpNewLike, // allocates; may return null
55  CallocLike = 1<<2, // allocates + bzero
56  ReallocLike = 1<<3, // reallocates
57  StrDupLike = 1<<4,
61 };
62 
63 struct AllocFnsTy {
65  unsigned NumParams;
66  // First and Second size parameters (or -1 if unused)
67  int FstParam, SndParam;
68 };
69 
70 // FIXME: certain users need more information. E.g., SimplifyLibCalls needs to
71 // know which functions are nounwind, noalias, nocapture parameters, etc.
72 static const std::pair<LibFunc, AllocFnsTy> AllocationFnData[] = {
73  {LibFunc_malloc, {MallocLike, 1, 0, -1}},
74  {LibFunc_valloc, {MallocLike, 1, 0, -1}},
75  {LibFunc_Znwj, {OpNewLike, 1, 0, -1}}, // new(unsigned int)
76  {LibFunc_ZnwjRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new(unsigned int, nothrow)
77  {LibFunc_ZnwjSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new(unsigned int, align_val_t)
78  {LibFunc_ZnwjSt11align_val_tRKSt9nothrow_t, // new(unsigned int, align_val_t, nothrow)
79  {MallocLike, 3, 0, -1}},
80  {LibFunc_Znwm, {OpNewLike, 1, 0, -1}}, // new(unsigned long)
81  {LibFunc_ZnwmRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new(unsigned long, nothrow)
82  {LibFunc_ZnwmSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new(unsigned long, align_val_t)
83  {LibFunc_ZnwmSt11align_val_tRKSt9nothrow_t, // new(unsigned long, align_val_t, nothrow)
84  {MallocLike, 3, 0, -1}},
85  {LibFunc_Znaj, {OpNewLike, 1, 0, -1}}, // new[](unsigned int)
86  {LibFunc_ZnajRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new[](unsigned int, nothrow)
87  {LibFunc_ZnajSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new[](unsigned int, align_val_t)
88  {LibFunc_ZnajSt11align_val_tRKSt9nothrow_t, // new[](unsigned int, align_val_t, nothrow)
89  {MallocLike, 3, 0, -1}},
90  {LibFunc_Znam, {OpNewLike, 1, 0, -1}}, // new[](unsigned long)
91  {LibFunc_ZnamRKSt9nothrow_t, {MallocLike, 2, 0, -1}}, // new[](unsigned long, nothrow)
92  {LibFunc_ZnamSt11align_val_t, {OpNewLike, 2, 0, -1}}, // new[](unsigned long, align_val_t)
93  {LibFunc_ZnamSt11align_val_tRKSt9nothrow_t, // new[](unsigned long, align_val_t, nothrow)
94  {MallocLike, 3, 0, -1}},
95  {LibFunc_msvc_new_int, {OpNewLike, 1, 0, -1}}, // new(unsigned int)
96  {LibFunc_msvc_new_int_nothrow, {MallocLike, 2, 0, -1}}, // new(unsigned int, nothrow)
97  {LibFunc_msvc_new_longlong, {OpNewLike, 1, 0, -1}}, // new(unsigned long long)
98  {LibFunc_msvc_new_longlong_nothrow, {MallocLike, 2, 0, -1}}, // new(unsigned long long, nothrow)
99  {LibFunc_msvc_new_array_int, {OpNewLike, 1, 0, -1}}, // new[](unsigned int)
100  {LibFunc_msvc_new_array_int_nothrow, {MallocLike, 2, 0, -1}}, // new[](unsigned int, nothrow)
101  {LibFunc_msvc_new_array_longlong, {OpNewLike, 1, 0, -1}}, // new[](unsigned long long)
102  {LibFunc_msvc_new_array_longlong_nothrow, {MallocLike, 2, 0, -1}}, // new[](unsigned long long, nothrow)
103  {LibFunc_calloc, {CallocLike, 2, 0, 1}},
104  {LibFunc_realloc, {ReallocLike, 2, 1, -1}},
105  {LibFunc_reallocf, {ReallocLike, 2, 1, -1}},
106  {LibFunc_strdup, {StrDupLike, 1, -1, -1}},
107  {LibFunc_strndup, {StrDupLike, 2, 1, -1}}
108  // TODO: Handle "int posix_memalign(void **, size_t, size_t)"
109 };
110 
111 static const Function *getCalledFunction(const Value *V, bool LookThroughBitCast,
112  bool &IsNoBuiltin) {
113  // Don't care about intrinsics in this case.
114  if (isa<IntrinsicInst>(V))
115  return nullptr;
116 
117  if (LookThroughBitCast)
118  V = V->stripPointerCasts();
119 
120  ImmutableCallSite CS(V);
121  if (!CS.getInstruction())
122  return nullptr;
123 
124  IsNoBuiltin = CS.isNoBuiltin();
125 
126  if (const Function *Callee = CS.getCalledFunction())
127  return Callee;
128  return nullptr;
129 }
130 
131 /// Returns the allocation data for the given value if it's either a call to a
132 /// known allocation function, or a call to a function with the allocsize
133 /// attribute.
136  const TargetLibraryInfo *TLI) {
137  // Make sure that the function is available.
138  StringRef FnName = Callee->getName();
139  LibFunc TLIFn;
140  if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
141  return None;
142 
143  const auto *Iter = find_if(
144  AllocationFnData, [TLIFn](const std::pair<LibFunc, AllocFnsTy> &P) {
145  return P.first == TLIFn;
146  });
147 
148  if (Iter == std::end(AllocationFnData))
149  return None;
150 
151  const AllocFnsTy *FnData = &Iter->second;
152  if ((FnData->AllocTy & AllocTy) != FnData->AllocTy)
153  return None;
154 
155  // Check function prototype.
156  int FstParam = FnData->FstParam;
157  int SndParam = FnData->SndParam;
158  FunctionType *FTy = Callee->getFunctionType();
159 
160  if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
161  FTy->getNumParams() == FnData->NumParams &&
162  (FstParam < 0 ||
163  (FTy->getParamType(FstParam)->isIntegerTy(32) ||
164  FTy->getParamType(FstParam)->isIntegerTy(64))) &&
165  (SndParam < 0 ||
166  FTy->getParamType(SndParam)->isIntegerTy(32) ||
167  FTy->getParamType(SndParam)->isIntegerTy(64)))
168  return *FnData;
169  return None;
170 }
171 
173  const TargetLibraryInfo *TLI,
174  bool LookThroughBitCast = false) {
175  bool IsNoBuiltinCall;
176  if (const Function *Callee =
177  getCalledFunction(V, LookThroughBitCast, IsNoBuiltinCall))
178  if (!IsNoBuiltinCall)
179  return getAllocationDataForFunction(Callee, AllocTy, TLI);
180  return None;
181 }
182 
184  const TargetLibraryInfo *TLI) {
185  bool IsNoBuiltinCall;
186  const Function *Callee =
187  getCalledFunction(V, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
188  if (!Callee)
189  return None;
190 
191  // Prefer to use existing information over allocsize. This will give us an
192  // accurate AllocTy.
193  if (!IsNoBuiltinCall)
196  return Data;
197 
198  Attribute Attr = Callee->getFnAttribute(Attribute::AllocSize);
199  if (Attr == Attribute())
200  return None;
201 
202  std::pair<unsigned, Optional<unsigned>> Args = Attr.getAllocSizeArgs();
203 
204  AllocFnsTy Result;
205  // Because allocsize only tells us how many bytes are allocated, we're not
206  // really allowed to assume anything, so we use MallocLike.
207  Result.AllocTy = MallocLike;
208  Result.NumParams = Callee->getNumOperands();
209  Result.FstParam = Args.first;
210  Result.SndParam = Args.second.getValueOr(-1);
211  return Result;
212 }
213 
214 static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
215  ImmutableCallSite CS(LookThroughBitCast ? V->stripPointerCasts() : V);
216  return CS && CS.hasRetAttr(Attribute::NoAlias);
217 }
218 
219 /// Tests if a value is a call or invoke to a library function that
220 /// allocates or reallocates memory (either malloc, calloc, realloc, or strdup
221 /// like).
222 bool llvm::isAllocationFn(const Value *V, const TargetLibraryInfo *TLI,
223  bool LookThroughBitCast) {
224  return getAllocationData(V, AnyAlloc, TLI, LookThroughBitCast).hasValue();
225 }
226 
227 /// Tests if a value is a call or invoke to a function that returns a
228 /// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions).
229 bool llvm::isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI,
230  bool LookThroughBitCast) {
231  // it's safe to consider realloc as noalias since accessing the original
232  // pointer is undefined behavior
233  return isAllocationFn(V, TLI, LookThroughBitCast) ||
234  hasNoAliasAttr(V, LookThroughBitCast);
235 }
236 
237 /// Tests if a value is a call or invoke to a library function that
238 /// allocates uninitialized memory (such as malloc).
239 bool llvm::isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
240  bool LookThroughBitCast) {
241  return getAllocationData(V, MallocLike, TLI, LookThroughBitCast).hasValue();
242 }
243 
244 /// Tests if a value is a call or invoke to a library function that
245 /// allocates zero-filled memory (such as calloc).
246 bool llvm::isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
247  bool LookThroughBitCast) {
248  return getAllocationData(V, CallocLike, TLI, LookThroughBitCast).hasValue();
249 }
250 
251 /// Tests if a value is a call or invoke to a library function that
252 /// allocates memory similar to malloc or calloc.
254  bool LookThroughBitCast) {
255  return getAllocationData(V, MallocOrCallocLike, TLI,
256  LookThroughBitCast).hasValue();
257 }
258 
259 /// Tests if a value is a call or invoke to a library function that
260 /// allocates memory (either malloc, calloc, or strdup like).
261 bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
262  bool LookThroughBitCast) {
263  return getAllocationData(V, AllocLike, TLI, LookThroughBitCast).hasValue();
264 }
265 
266 /// extractMallocCall - Returns the corresponding CallInst if the instruction
267 /// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
268 /// ignore InvokeInst here.
270  const TargetLibraryInfo *TLI) {
271  return isMallocLikeFn(I, TLI) ? dyn_cast<CallInst>(I) : nullptr;
272 }
273 
274 static Value *computeArraySize(const CallInst *CI, const DataLayout &DL,
275  const TargetLibraryInfo *TLI,
276  bool LookThroughSExt = false) {
277  if (!CI)
278  return nullptr;
279 
280  // The size of the malloc's result type must be known to determine array size.
281  Type *T = getMallocAllocatedType(CI, TLI);
282  if (!T || !T->isSized())
283  return nullptr;
284 
285  unsigned ElementSize = DL.getTypeAllocSize(T);
286  if (StructType *ST = dyn_cast<StructType>(T))
287  ElementSize = DL.getStructLayout(ST)->getSizeInBytes();
288 
289  // If malloc call's arg can be determined to be a multiple of ElementSize,
290  // return the multiple. Otherwise, return NULL.
291  Value *MallocArg = CI->getArgOperand(0);
292  Value *Multiple = nullptr;
293  if (ComputeMultiple(MallocArg, ElementSize, Multiple, LookThroughSExt))
294  return Multiple;
295 
296  return nullptr;
297 }
298 
299 /// getMallocType - Returns the PointerType resulting from the malloc call.
300 /// The PointerType depends on the number of bitcast uses of the malloc call:
301 /// 0: PointerType is the calls' return type.
302 /// 1: PointerType is the bitcast's result type.
303 /// >1: Unique PointerType cannot be determined, return NULL.
305  const TargetLibraryInfo *TLI) {
306  assert(isMallocLikeFn(CI, TLI) && "getMallocType and not malloc call");
307 
308  PointerType *MallocType = nullptr;
309  unsigned NumOfBitCastUses = 0;
310 
311  // Determine if CallInst has a bitcast use.
312  for (Value::const_user_iterator UI = CI->user_begin(), E = CI->user_end();
313  UI != E;)
314  if (const BitCastInst *BCI = dyn_cast<BitCastInst>(*UI++)) {
315  MallocType = cast<PointerType>(BCI->getDestTy());
316  NumOfBitCastUses++;
317  }
318 
319  // Malloc call has 1 bitcast use, so type is the bitcast's destination type.
320  if (NumOfBitCastUses == 1)
321  return MallocType;
322 
323  // Malloc call was not bitcast, so type is the malloc function's return type.
324  if (NumOfBitCastUses == 0)
325  return cast<PointerType>(CI->getType());
326 
327  // Type could not be determined.
328  return nullptr;
329 }
330 
331 /// getMallocAllocatedType - Returns the Type allocated by malloc call.
332 /// The Type depends on the number of bitcast uses of the malloc call:
333 /// 0: PointerType is the malloc calls' return type.
334 /// 1: PointerType is the bitcast's result type.
335 /// >1: Unique PointerType cannot be determined, return NULL.
337  const TargetLibraryInfo *TLI) {
338  PointerType *PT = getMallocType(CI, TLI);
339  return PT ? PT->getElementType() : nullptr;
340 }
341 
342 /// getMallocArraySize - Returns the array size of a malloc call. If the
343 /// argument passed to malloc is a multiple of the size of the malloced type,
344 /// then return that multiple. For non-array mallocs, the multiple is
345 /// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
346 /// determined.
348  const TargetLibraryInfo *TLI,
349  bool LookThroughSExt) {
350  assert(isMallocLikeFn(CI, TLI) && "getMallocArraySize and not malloc call");
351  return computeArraySize(CI, DL, TLI, LookThroughSExt);
352 }
353 
354 /// extractCallocCall - Returns the corresponding CallInst if the instruction
355 /// is a calloc call.
357  const TargetLibraryInfo *TLI) {
358  return isCallocLikeFn(I, TLI) ? cast<CallInst>(I) : nullptr;
359 }
360 
361 /// isFreeCall - Returns non-null if the value is a call to the builtin free()
362 const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
363  bool IsNoBuiltinCall;
364  const Function *Callee =
365  getCalledFunction(I, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
366  if (Callee == nullptr || IsNoBuiltinCall)
367  return nullptr;
368 
369  StringRef FnName = Callee->getName();
370  LibFunc TLIFn;
371  if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
372  return nullptr;
373 
374  unsigned ExpectedNumParams;
375  if (TLIFn == LibFunc_free ||
376  TLIFn == LibFunc_ZdlPv || // operator delete(void*)
377  TLIFn == LibFunc_ZdaPv || // operator delete[](void*)
378  TLIFn == LibFunc_msvc_delete_ptr32 || // operator delete(void*)
379  TLIFn == LibFunc_msvc_delete_ptr64 || // operator delete(void*)
380  TLIFn == LibFunc_msvc_delete_array_ptr32 || // operator delete[](void*)
381  TLIFn == LibFunc_msvc_delete_array_ptr64) // operator delete[](void*)
382  ExpectedNumParams = 1;
383  else if (TLIFn == LibFunc_ZdlPvj || // delete(void*, uint)
384  TLIFn == LibFunc_ZdlPvm || // delete(void*, ulong)
385  TLIFn == LibFunc_ZdlPvRKSt9nothrow_t || // delete(void*, nothrow)
386  TLIFn == LibFunc_ZdlPvSt11align_val_t || // delete(void*, align_val_t)
387  TLIFn == LibFunc_ZdaPvj || // delete[](void*, uint)
388  TLIFn == LibFunc_ZdaPvm || // delete[](void*, ulong)
389  TLIFn == LibFunc_ZdaPvRKSt9nothrow_t || // delete[](void*, nothrow)
390  TLIFn == LibFunc_ZdaPvSt11align_val_t || // delete[](void*, align_val_t)
391  TLIFn == LibFunc_msvc_delete_ptr32_int || // delete(void*, uint)
392  TLIFn == LibFunc_msvc_delete_ptr64_longlong || // delete(void*, ulonglong)
393  TLIFn == LibFunc_msvc_delete_ptr32_nothrow || // delete(void*, nothrow)
394  TLIFn == LibFunc_msvc_delete_ptr64_nothrow || // delete(void*, nothrow)
395  TLIFn == LibFunc_msvc_delete_array_ptr32_int || // delete[](void*, uint)
396  TLIFn == LibFunc_msvc_delete_array_ptr64_longlong || // delete[](void*, ulonglong)
397  TLIFn == LibFunc_msvc_delete_array_ptr32_nothrow || // delete[](void*, nothrow)
398  TLIFn == LibFunc_msvc_delete_array_ptr64_nothrow) // delete[](void*, nothrow)
399  ExpectedNumParams = 2;
400  else if (TLIFn == LibFunc_ZdaPvSt11align_val_tRKSt9nothrow_t || // delete(void*, align_val_t, nothrow)
401  TLIFn == LibFunc_ZdlPvSt11align_val_tRKSt9nothrow_t) // delete[](void*, align_val_t, nothrow)
402  ExpectedNumParams = 3;
403  else
404  return nullptr;
405 
406  // Check free prototype.
407  // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
408  // attribute will exist.
409  FunctionType *FTy = Callee->getFunctionType();
410  if (!FTy->getReturnType()->isVoidTy())
411  return nullptr;
412  if (FTy->getNumParams() != ExpectedNumParams)
413  return nullptr;
414  if (FTy->getParamType(0) != Type::getInt8PtrTy(Callee->getContext()))
415  return nullptr;
416 
417  return dyn_cast<CallInst>(I);
418 }
419 
420 //===----------------------------------------------------------------------===//
421 // Utility functions to compute size of objects.
422 //
424  if (Data.second.isNegative() || Data.first.ult(Data.second))
425  return APInt(Data.first.getBitWidth(), 0);
426  return Data.first - Data.second;
427 }
428 
429 /// Compute the size of the object pointed by Ptr. Returns true and the
430 /// object size in Size if successful, and false otherwise.
431 /// If RoundToAlign is true, then Size is rounded up to the alignment of
432 /// allocas, byval arguments, and global variables.
433 bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
434  const TargetLibraryInfo *TLI, ObjectSizeOpts Opts) {
435  ObjectSizeOffsetVisitor Visitor(DL, TLI, Ptr->getContext(), Opts);
436  SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
437  if (!Visitor.bothKnown(Data))
438  return false;
439 
440  Size = getSizeWithOverflow(Data).getZExtValue();
441  return true;
442 }
443 
445  const DataLayout &DL,
446  const TargetLibraryInfo *TLI,
447  bool MustSucceed) {
448  assert(ObjectSize->getIntrinsicID() == Intrinsic::objectsize &&
449  "ObjectSize must be a call to llvm.objectsize!");
450 
451  bool MaxVal = cast<ConstantInt>(ObjectSize->getArgOperand(1))->isZero();
452  ObjectSizeOpts EvalOptions;
453  // Unless we have to fold this to something, try to be as accurate as
454  // possible.
455  if (MustSucceed)
456  EvalOptions.EvalMode =
458  else
460 
461  EvalOptions.NullIsUnknownSize =
462  cast<ConstantInt>(ObjectSize->getArgOperand(2))->isOne();
463 
464  auto *ResultType = cast<IntegerType>(ObjectSize->getType());
465  bool StaticOnly = cast<ConstantInt>(ObjectSize->getArgOperand(3))->isZero();
466  if (StaticOnly) {
467  // FIXME: Does it make sense to just return a failure value if the size won't
468  // fit in the output and `!MustSucceed`?
469  uint64_t Size;
470  if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, EvalOptions) &&
471  isUIntN(ResultType->getBitWidth(), Size))
472  return ConstantInt::get(ResultType, Size);
473  } else {
474  LLVMContext &Ctx = ObjectSize->getFunction()->getContext();
475  ObjectSizeOffsetEvaluator Eval(DL, TLI, Ctx, EvalOptions);
476  SizeOffsetEvalType SizeOffsetPair =
477  Eval.compute(ObjectSize->getArgOperand(0));
478 
479  if (SizeOffsetPair != ObjectSizeOffsetEvaluator::unknown()) {
480  IRBuilder<TargetFolder> Builder(Ctx, TargetFolder(DL));
481  Builder.SetInsertPoint(ObjectSize);
482 
483  // If we've outside the end of the object, then we can always access
484  // exactly 0 bytes.
485  Value *ResultSize =
486  Builder.CreateSub(SizeOffsetPair.first, SizeOffsetPair.second);
487  Value *UseZero =
488  Builder.CreateICmpULT(SizeOffsetPair.first, SizeOffsetPair.second);
489  return Builder.CreateSelect(UseZero, ConstantInt::get(ResultType, 0),
490  ResultSize);
491  }
492  }
493 
494  if (!MustSucceed)
495  return nullptr;
496 
497  return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0);
498 }
499 
500 STATISTIC(ObjectVisitorArgument,
501  "Number of arguments with unsolved size and offset");
502 STATISTIC(ObjectVisitorLoad,
503  "Number of load instructions with unsolved size and offset");
504 
505 APInt ObjectSizeOffsetVisitor::align(APInt Size, uint64_t Align) {
506  if (Options.RoundToAlign && Align)
507  return APInt(IntTyBits, alignTo(Size.getZExtValue(), Align));
508  return Size;
509 }
510 
512  const TargetLibraryInfo *TLI,
514  ObjectSizeOpts Options)
515  : DL(DL), TLI(TLI), Options(Options) {
516  // Pointer size must be rechecked for each object visited since it could have
517  // a different address space.
518 }
519 
521  IntTyBits = DL.getPointerTypeSizeInBits(V->getType());
522  Zero = APInt::getNullValue(IntTyBits);
523 
524  V = V->stripPointerCasts();
525  if (Instruction *I = dyn_cast<Instruction>(V)) {
526  // If we have already seen this instruction, bail out. Cycles can happen in
527  // unreachable code after constant propagation.
528  if (!SeenInsts.insert(I).second)
529  return unknown();
530 
531  if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
532  return visitGEPOperator(*GEP);
533  return visit(*I);
534  }
535  if (Argument *A = dyn_cast<Argument>(V))
536  return visitArgument(*A);
537  if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
538  return visitConstantPointerNull(*P);
539  if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
540  return visitGlobalAlias(*GA);
541  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
542  return visitGlobalVariable(*GV);
543  if (UndefValue *UV = dyn_cast<UndefValue>(V))
544  return visitUndefValue(*UV);
545  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
546  if (CE->getOpcode() == Instruction::IntToPtr)
547  return unknown(); // clueless
548  if (CE->getOpcode() == Instruction::GetElementPtr)
549  return visitGEPOperator(cast<GEPOperator>(*CE));
550  }
551 
552  LLVM_DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: "
553  << *V << '\n');
554  return unknown();
555 }
556 
557 /// When we're compiling N-bit code, and the user uses parameters that are
558 /// greater than N bits (e.g. uint64_t on a 32-bit build), we can run into
559 /// trouble with APInt size issues. This function handles resizing + overflow
560 /// checks for us. Check and zext or trunc \p I depending on IntTyBits and
561 /// I's value.
562 bool ObjectSizeOffsetVisitor::CheckedZextOrTrunc(APInt &I) {
563  // More bits than we can handle. Checking the bit width isn't necessary, but
564  // it's faster than checking active bits, and should give `false` in the
565  // vast majority of cases.
566  if (I.getBitWidth() > IntTyBits && I.getActiveBits() > IntTyBits)
567  return false;
568  if (I.getBitWidth() != IntTyBits)
569  I = I.zextOrTrunc(IntTyBits);
570  return true;
571 }
572 
574  if (!I.getAllocatedType()->isSized())
575  return unknown();
576 
577  APInt Size(IntTyBits, DL.getTypeAllocSize(I.getAllocatedType()));
578  if (!I.isArrayAllocation())
579  return std::make_pair(align(Size, I.getAlignment()), Zero);
580 
581  Value *ArraySize = I.getArraySize();
582  if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
583  APInt NumElems = C->getValue();
584  if (!CheckedZextOrTrunc(NumElems))
585  return unknown();
586 
587  bool Overflow;
588  Size = Size.umul_ov(NumElems, Overflow);
589  return Overflow ? unknown() : std::make_pair(align(Size, I.getAlignment()),
590  Zero);
591  }
592  return unknown();
593 }
594 
596  // No interprocedural analysis is done at the moment.
597  if (!A.hasByValOrInAllocaAttr()) {
598  ++ObjectVisitorArgument;
599  return unknown();
600  }
601  PointerType *PT = cast<PointerType>(A.getType());
602  APInt Size(IntTyBits, DL.getTypeAllocSize(PT->getElementType()));
603  return std::make_pair(align(Size, A.getParamAlignment()), Zero);
604 }
605 
608  if (!FnData)
609  return unknown();
610 
611  // Handle strdup-like functions separately.
612  if (FnData->AllocTy == StrDupLike) {
613  APInt Size(IntTyBits, GetStringLength(CS.getArgument(0)));
614  if (!Size)
615  return unknown();
616 
617  // Strndup limits strlen.
618  if (FnData->FstParam > 0) {
619  ConstantInt *Arg =
621  if (!Arg)
622  return unknown();
623 
624  APInt MaxSize = Arg->getValue().zextOrSelf(IntTyBits);
625  if (Size.ugt(MaxSize))
626  Size = MaxSize + 1;
627  }
628  return std::make_pair(Size, Zero);
629  }
630 
632  if (!Arg)
633  return unknown();
634 
635  APInt Size = Arg->getValue();
636  if (!CheckedZextOrTrunc(Size))
637  return unknown();
638 
639  // Size is determined by just 1 parameter.
640  if (FnData->SndParam < 0)
641  return std::make_pair(Size, Zero);
642 
643  Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->SndParam));
644  if (!Arg)
645  return unknown();
646 
647  APInt NumElems = Arg->getValue();
648  if (!CheckedZextOrTrunc(NumElems))
649  return unknown();
650 
651  bool Overflow;
652  Size = Size.umul_ov(NumElems, Overflow);
653  return Overflow ? unknown() : std::make_pair(Size, Zero);
654 
655  // TODO: handle more standard functions (+ wchar cousins):
656  // - strdup / strndup
657  // - strcpy / strncpy
658  // - strcat / strncat
659  // - memcpy / memmove
660  // - strcat / strncat
661  // - memset
662 }
663 
666  // If null is unknown, there's nothing we can do. Additionally, non-zero
667  // address spaces can make use of null, so we don't presume to know anything
668  // about that.
669  //
670  // TODO: How should this work with address space casts? We currently just drop
671  // them on the floor, but it's unclear what we should do when a NULL from
672  // addrspace(1) gets casted to addrspace(0) (or vice-versa).
673  if (Options.NullIsUnknownSize || CPN.getType()->getAddressSpace())
674  return unknown();
675  return std::make_pair(Zero, Zero);
676 }
677 
680  return unknown();
681 }
682 
685  // Easy cases were already folded by previous passes.
686  return unknown();
687 }
688 
690  SizeOffsetType PtrData = compute(GEP.getPointerOperand());
691  APInt Offset(IntTyBits, 0);
692  if (!bothKnown(PtrData) || !GEP.accumulateConstantOffset(DL, Offset))
693  return unknown();
694 
695  return std::make_pair(PtrData.first, PtrData.second + Offset);
696 }
697 
699  if (GA.isInterposable())
700  return unknown();
701  return compute(GA.getAliasee());
702 }
703 
705  if (!GV.hasDefinitiveInitializer())
706  return unknown();
707 
708  APInt Size(IntTyBits, DL.getTypeAllocSize(GV.getType()->getElementType()));
709  return std::make_pair(align(Size, GV.getAlignment()), Zero);
710 }
711 
713  // clueless
714  return unknown();
715 }
716 
718  ++ObjectVisitorLoad;
719  return unknown();
720 }
721 
723  // too complex to analyze statically.
724  return unknown();
725 }
726 
728  SizeOffsetType TrueSide = compute(I.getTrueValue());
729  SizeOffsetType FalseSide = compute(I.getFalseValue());
730  if (bothKnown(TrueSide) && bothKnown(FalseSide)) {
731  if (TrueSide == FalseSide) {
732  return TrueSide;
733  }
734 
735  APInt TrueResult = getSizeWithOverflow(TrueSide);
736  APInt FalseResult = getSizeWithOverflow(FalseSide);
737 
738  if (TrueResult == FalseResult) {
739  return TrueSide;
740  }
741  if (Options.EvalMode == ObjectSizeOpts::Mode::Min) {
742  if (TrueResult.slt(FalseResult))
743  return TrueSide;
744  return FalseSide;
745  }
746  if (Options.EvalMode == ObjectSizeOpts::Mode::Max) {
747  if (TrueResult.sgt(FalseResult))
748  return TrueSide;
749  return FalseSide;
750  }
751  }
752  return unknown();
753 }
754 
756  return std::make_pair(Zero, Zero);
757 }
758 
760  LLVM_DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I
761  << '\n');
762  return unknown();
763 }
764 
766  const DataLayout &DL, const TargetLibraryInfo *TLI, LLVMContext &Context,
767  ObjectSizeOpts EvalOpts)
768  : DL(DL), TLI(TLI), Context(Context),
769  Builder(Context, TargetFolder(DL),
771  [&](Instruction *I) { InsertedInstructions.insert(I); })),
772  EvalOpts(EvalOpts) {
773  // IntTy and Zero must be set for each compute() since the address space may
774  // be different for later objects.
775 }
776 
778  // XXX - Are vectors of pointers possible here?
779  IntTy = cast<IntegerType>(DL.getIntPtrType(V->getType()));
780  Zero = ConstantInt::get(IntTy, 0);
781 
782  SizeOffsetEvalType Result = compute_(V);
783 
784  if (!bothKnown(Result)) {
785  // Erase everything that was computed in this iteration from the cache, so
786  // that no dangling references are left behind. We could be a bit smarter if
787  // we kept a dependency graph. It's probably not worth the complexity.
788  for (const Value *SeenVal : SeenVals) {
789  CacheMapTy::iterator CacheIt = CacheMap.find(SeenVal);
790  // non-computable results can be safely cached
791  if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
792  CacheMap.erase(CacheIt);
793  }
794 
795  // Erase any instructions we inserted as part of the traversal.
796  for (Instruction *I : InsertedInstructions) {
797  I->replaceAllUsesWith(UndefValue::get(I->getType()));
798  I->eraseFromParent();
799  }
800  }
801 
802  SeenVals.clear();
803  InsertedInstructions.clear();
804  return Result;
805 }
806 
807 SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
808  ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, EvalOpts);
809  SizeOffsetType Const = Visitor.compute(V);
810  if (Visitor.bothKnown(Const))
811  return std::make_pair(ConstantInt::get(Context, Const.first),
812  ConstantInt::get(Context, Const.second));
813 
814  V = V->stripPointerCasts();
815 
816  // Check cache.
817  CacheMapTy::iterator CacheIt = CacheMap.find(V);
818  if (CacheIt != CacheMap.end())
819  return CacheIt->second;
820 
821  // Always generate code immediately before the instruction being
822  // processed, so that the generated code dominates the same BBs.
823  BuilderTy::InsertPointGuard Guard(Builder);
824  if (Instruction *I = dyn_cast<Instruction>(V))
825  Builder.SetInsertPoint(I);
826 
827  // Now compute the size and offset.
828  SizeOffsetEvalType Result;
829 
830  // Record the pointers that were handled in this run, so that they can be
831  // cleaned later if something fails. We also use this set to break cycles that
832  // can occur in dead code.
833  if (!SeenVals.insert(V).second) {
834  Result = unknown();
835  } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
836  Result = visitGEPOperator(*GEP);
837  } else if (Instruction *I = dyn_cast<Instruction>(V)) {
838  Result = visit(*I);
839  } else if (isa<Argument>(V) ||
840  (isa<ConstantExpr>(V) &&
841  cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
842  isa<GlobalAlias>(V) ||
843  isa<GlobalVariable>(V)) {
844  // Ignore values where we cannot do more than ObjectSizeVisitor.
845  Result = unknown();
846  } else {
847  LLVM_DEBUG(
848  dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: " << *V
849  << '\n');
850  Result = unknown();
851  }
852 
853  // Don't reuse CacheIt since it may be invalid at this point.
854  CacheMap[V] = Result;
855  return Result;
856 }
857 
859  if (!I.getAllocatedType()->isSized())
860  return unknown();
861 
862  // must be a VLA
864  Value *ArraySize = I.getArraySize();
865  Value *Size = ConstantInt::get(ArraySize->getType(),
867  Size = Builder.CreateMul(Size, ArraySize);
868  return std::make_pair(Size, Zero);
869 }
870 
873  if (!FnData)
874  return unknown();
875 
876  // Handle strdup-like functions separately.
877  if (FnData->AllocTy == StrDupLike) {
878  // TODO
879  return unknown();
880  }
881 
882  Value *FirstArg = CS.getArgument(FnData->FstParam);
883  FirstArg = Builder.CreateZExt(FirstArg, IntTy);
884  if (FnData->SndParam < 0)
885  return std::make_pair(FirstArg, Zero);
886 
887  Value *SecondArg = CS.getArgument(FnData->SndParam);
888  SecondArg = Builder.CreateZExt(SecondArg, IntTy);
889  Value *Size = Builder.CreateMul(FirstArg, SecondArg);
890  return std::make_pair(Size, Zero);
891 
892  // TODO: handle more standard functions (+ wchar cousins):
893  // - strdup / strndup
894  // - strcpy / strncpy
895  // - strcat / strncat
896  // - memcpy / memmove
897  // - strcat / strncat
898  // - memset
899 }
900 
903  return unknown();
904 }
905 
908  return unknown();
909 }
910 
913  SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
914  if (!bothKnown(PtrData))
915  return unknown();
916 
917  Value *Offset = EmitGEPOffset(&Builder, DL, &GEP, /*NoAssumptions=*/true);
918  Offset = Builder.CreateAdd(PtrData.second, Offset);
919  return std::make_pair(PtrData.first, Offset);
920 }
921 
923  // clueless
924  return unknown();
925 }
926 
928  return unknown();
929 }
930 
932  // Create 2 PHIs: one for size and another for offset.
933  PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
934  PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
935 
936  // Insert right away in the cache to handle recursive PHIs.
937  CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
938 
939  // Compute offset/size for each PHI incoming pointer.
940  for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
942  SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
943 
944  if (!bothKnown(EdgeData)) {
945  OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
946  OffsetPHI->eraseFromParent();
947  InsertedInstructions.erase(OffsetPHI);
948  SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
949  SizePHI->eraseFromParent();
950  InsertedInstructions.erase(SizePHI);
951  return unknown();
952  }
953  SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
954  OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
955  }
956 
957  Value *Size = SizePHI, *Offset = OffsetPHI;
958  if (Value *Tmp = SizePHI->hasConstantValue()) {
959  Size = Tmp;
960  SizePHI->replaceAllUsesWith(Size);
961  SizePHI->eraseFromParent();
962  InsertedInstructions.erase(SizePHI);
963  }
964  if (Value *Tmp = OffsetPHI->hasConstantValue()) {
965  Offset = Tmp;
966  OffsetPHI->replaceAllUsesWith(Offset);
967  OffsetPHI->eraseFromParent();
968  InsertedInstructions.erase(OffsetPHI);
969  }
970  return std::make_pair(Size, Offset);
971 }
972 
974  SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
975  SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
976 
977  if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
978  return unknown();
979  if (TrueSide == FalseSide)
980  return TrueSide;
981 
982  Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
983  FalseSide.first);
984  Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
985  FalseSide.second);
986  return std::make_pair(Size, Offset);
987 }
988 
990  LLVM_DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I
991  << '\n');
992  return unknown();
993 }
bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL, const TargetLibraryInfo *TLI, ObjectSizeOpts Opts={})
Compute the size of the object pointed by Ptr.
Value * EmitGEPOffset(IRBuilderTy *Builder, const DataLayout &DL, User *GEP, bool NoAssumptions=false)
Given a getelementptr instruction/constantexpr, emit the code necessary to compute the offset from th...
Definition: Local.h:28
uint64_t CallInst * C
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:67
unsigned getAlignment() const
Definition: GlobalObject.h:58
bool isAllocationFn(const Value *V, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
Tests if a value is a call or invoke to a library function that allocates or reallocates memory (eith...
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:110
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:233
constexpr char Align[]
Key for Kernel::Arg::Metadata::mAlign.
bool hasDefinitiveInitializer() const
hasDefinitiveInitializer - Whether the global variable has an initializer, and any other instances of...
static const std::pair< LibFunc, AllocFnsTy > AllocationFnData[]
void addIncoming(Value *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
This instruction extracts a struct member or array element value from an aggregate value...
uint64_t getZExtValue() const
Get zero extended value.
Definition: APInt.h:1562
This class represents an incoming formal argument to a Function.
Definition: Argument.h:29
LLVMContext & Context
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Type * getParamType(unsigned i) const
Parameter type accessors.
Definition: DerivedTypes.h:134
Value * CreateICmpULT(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1890
static SizeOffsetEvalType unknown()
bool isSized(SmallPtrSetImpl< Type *> *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:264
unsigned NumParams
const CallInst * extractCallocCall(const Value *I, const TargetLibraryInfo *TLI)
extractCallocCall - Returns the corresponding CallInst if the instruction is a calloc call...
const StructLayout * getStructLayout(StructType *Ty) const
Returns a StructLayout object, indicating the alignment of the struct, its size, and the offsets of i...
Definition: DataLayout.cpp:607
bool hasByValOrInAllocaAttr() const
Return true if this argument has the byval attribute or inalloca attribute.
Definition: Function.cpp:104
std::pair< Value *, Value * > SizeOffsetEvalType
bool NullIsUnknownSize
If this is true, null pointers in address space 0 will be treated as though they can&#39;t be evaluated...
bool slt(const APInt &RHS) const
Signed less than comparison.
Definition: APInt.h:1203
This class represents a function call, abstracting a target machine&#39;s calling convention.
static Optional< AllocFnsTy > getAllocationDataForFunction(const Function *Callee, AllocType AllocTy, const TargetLibraryInfo *TLI)
Returns the allocation data for the given value if it&#39;s either a call to a known allocation function...
const Value * getTrueValue() const
The two locations do not alias at all.
Definition: AliasAnalysis.h:84
LLVMContext & getContext() const
All values hold a context through their type.
Definition: Value.cpp:709
bool hasRetAttr(Attribute::AttrKind Kind) const
Return true if this return value has the given attribute.
Definition: CallSite.h:380
SizeOffsetType visitAllocaInst(AllocaInst &I)
bool isInterposable() const
Return true if this global&#39;s definition can be substituted with an arbitrary definition at link time...
Definition: GlobalValue.h:419
bool sgt(const APInt &RHS) const
Signed greather than comparison.
Definition: APInt.h:1273
AllocType
STATISTIC(NumFunctions, "Total number of functions")
uint64_t alignTo(uint64_t Value, uint64_t Align, uint64_t Skew=0)
Returns the next integer (mod 2**64) that is greater than or equal to Value and is a multiple of Alig...
Definition: MathExtras.h:684
An instruction for reading from memory.
Definition: Instructions.h:167
FunTy * getCalledFunction() const
Return the function being called if this is a direct call, otherwise return null (if it&#39;s an indirect...
Definition: CallSite.h:111
APInt zextOrTrunc(unsigned width) const
Zero extend or truncate to width.
Definition: APInt.cpp:875
SizeOffsetType visitArgument(Argument &A)
Hexagon Common GEP
unsigned getBitWidth() const
Return the number of bits in the APInt.
Definition: APInt.h:1508
bool accumulateConstantOffset(const DataLayout &DL, APInt &Offset) const
Accumulate the constant address offset of this GEP if possible.
Definition: Operator.cpp:34
LLVMContext & getContext() const
Return the LLVMContext in which this type was uniqued.
Definition: Type.h:129
const CallInst * isFreeCall(const Value *I, const TargetLibraryInfo *TLI)
isFreeCall - Returns non-null if the value is a call to the builtin free()
Value * getArgOperand(unsigned i) const
Definition: InstrTypes.h:1218
This class represents the LLVM &#39;select&#39; instruction.
unsigned getAlignment() const
Return the alignment of the memory that is being allocated by the instruction.
Definition: Instructions.h:112
SizeOffsetEvalType visitGEPOperator(GEPOperator &GEP)
SizeOffsetType visitExtractValueInst(ExtractValueInst &I)
SizeOffsetType visitGEPOperator(GEPOperator &GEP)
unsigned getPointerTypeSizeInBits(Type *) const
Layout pointer size, in bits, based on the type.
Definition: DataLayout.cpp:665
&#39;undef&#39; values are things that do not have specified contents.
Definition: Constants.h:1285
static Optional< AllocFnsTy > getAllocationSize(const Value *V, const TargetLibraryInfo *TLI)
Class to represent struct types.
Definition: DerivedTypes.h:232
APInt zextOrSelf(unsigned width) const
Zero extend or truncate to width.
Definition: APInt.cpp:891
static Optional< unsigned > getOpcode(ArrayRef< VPValue *> Values)
Returns the opcode of Values or ~0 if they do not all agree.
Definition: VPlanSLP.cpp:196
bool isIntegerTy() const
True if this is an instance of IntegerType.
Definition: Type.h:196
SizeOffsetEvalType visitCallSite(CallSite CS)
SizeOffsetType visitIntToPtrInst(IntToPtrInst &)
This file contains the simple types necessary to represent the attributes associated with functions a...
Value * CreateAdd(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1049
This file implements a class to represent arbitrary precision integral constant values and operations...
Value * lowerObjectSizeCall(IntrinsicInst *ObjectSize, const DataLayout &DL, const TargetLibraryInfo *TLI, bool MustSucceed)
Try to turn a call to @llvm.objectsize into an integer value of the given Type.
InstrTy * getInstruction() const
Definition: CallSite.h:96
unsigned getActiveBits() const
Compute the number of active bits in the value.
Definition: APInt.h:1532
bool isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
Tests if a value is a call or invoke to a function that returns a NoAlias pointer (including malloc/c...
Same as Min, except we pick the maximum size of all of the branches.
A constant value that is initialized with an expression using other constant values.
Definition: Constants.h:888
Class to represent function types.
Definition: DerivedTypes.h:102
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:244
Evaluate all branches of an unknown condition.
Evaluate the size and offset of an object pointed to by a Value*.
bool has(LibFunc F) const
Tests whether a library function is available.
This class represents a no-op cast from one type to another.
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:137
TargetFolder - Create constants with target dependent folding.
Definition: TargetFolder.h:31
Value * CreateSub(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1066
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:429
std::pair< unsigned, Optional< unsigned > > getAllocSizeArgs() const
Returns the argument numbers for the allocsize attribute (or pair(0, 0) if not known).
Definition: Attributes.cpp:236
Value * CreateZExt(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1694
uint64_t GetStringLength(const Value *V, unsigned CharSize=8)
If we can compute the length of the string pointed to by the specified pointer, return &#39;len+1&#39;...
SizeOffsetType visitInstruction(Instruction &I)
void SetInsertPoint(BasicBlock *TheBB)
This specifies that created instructions should be appended to the end of the specified block...
Definition: IRBuilder.h:126
Class to represent pointers.
Definition: DerivedTypes.h:498
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:176
Value * getMallocArraySize(CallInst *CI, const DataLayout &DL, const TargetLibraryInfo *TLI, bool LookThroughSExt=false)
getMallocArraySize - Returns the array size of a malloc call.
SizeOffsetType visitGlobalVariable(GlobalVariable &GV)
bool isVoidTy() const
Return true if this is &#39;void&#39;.
Definition: Type.h:140
IntegerType * getIntPtrType(LLVMContext &C, unsigned AddressSpace=0) const
Returns an integer type with size at least as big as that of a pointer in the given address space...
Definition: DataLayout.cpp:769
#define P(N)
bool erase(const KeyT &Val)
Definition: DenseMap.h:298
bool isNoBuiltin() const
Return true if the call should not be treated as a call to a builtin.
Definition: CallSite.h:436
SizeOffsetEvalType visitSelectInst(SelectInst &I)
const_iterator getFirstInsertionPt() const
Returns an iterator to the first instruction in this block that is suitable for inserting a non-PHI i...
Definition: BasicBlock.cpp:216
ObjectSizeOffsetEvaluator(const DataLayout &DL, const TargetLibraryInfo *TLI, LLVMContext &Context, ObjectSizeOpts EvalOpts={})
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:64
const CallInst * extractMallocCall(const Value *I, const TargetLibraryInfo *TLI)
extractMallocCall - Returns the corresponding CallInst if the instruction is a malloc call...
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This file contains the declarations for the subclasses of Constant, which represent the different fla...
Value * CreateSelect(Value *C, Value *True, Value *False, const Twine &Name="", Instruction *MDFrom=nullptr)
Definition: IRBuilder.h:2057
ValTy * getArgument(unsigned ArgNo) const
Definition: CallSite.h:193
unsigned getNumParams() const
Return the number of fixed parameters this function type requires.
Definition: DerivedTypes.h:138
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:370
static Value * computeArraySize(const CallInst *CI, const DataLayout &DL, const TargetLibraryInfo *TLI, bool LookThroughSExt=false)
static APInt getSizeWithOverflow(const SizeOffsetType &Data)
Value * getPointerOperand()
Definition: Operator.h:473
amdgpu Simplify well known AMD library false FunctionCallee Value * Arg
static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast)
unsigned getAddressSpace() const
Return the address space of the Pointer type.
Definition: DerivedTypes.h:526
static Optional< AllocFnsTy > getAllocationData(const Value *V, AllocType AllocTy, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range))
Provide wrappers to std::find_if which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1213
const Function * getFunction() const
Return the function this instruction belongs to.
Definition: Instruction.cpp:59
This class represents a cast from an integer to a pointer.
const Value * getCondition() const
LLVMContext & getContext() const
getContext - Return a reference to the LLVMContext associated with this function. ...
Definition: Function.cpp:196
static UndefValue * get(Type *T)
Static factory methods - Return an &#39;undef&#39; object of the specified type.
Definition: Constants.cpp:1424
const Value * stripPointerCasts() const
Strip off pointer casts, all-zero GEPs, and aliases.
Definition: Value.cpp:529
SizeOffsetType visitCallSite(CallSite CS)
const Value * getArraySize() const
Get the number of elements allocated.
Definition: Instructions.h:92
std::pair< APInt, APInt > SizeOffsetType
Value * getIncomingValue(unsigned i) const
Return incoming value number x.
static PointerType * getInt8PtrTy(LLVMContext &C, unsigned AS=0)
Definition: Type.cpp:219
PointerType * getMallocType(const CallInst *CI, const TargetLibraryInfo *TLI)
getMallocType - Returns the PointerType resulting from the malloc call.
Value * CreateMul(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:1083
Type * getAllocatedType() const
Return the type that is being allocated by the instruction.
Definition: Instructions.h:105
SizeOffsetType visitSelectInst(SelectInst &I)
Intrinsic::ID getIntrinsicID() const
Return the intrinsic ID of this intrinsic.
Definition: IntrinsicInst.h:50
SizeOffsetType visitExtractElementInst(ExtractElementInst &I)
SizeOffsetType visitGlobalAlias(GlobalAlias &GA)
PHINode * CreatePHI(Type *Ty, unsigned NumReservedValues, const Twine &Name="")
Definition: IRBuilder.h:2004
SizeOffsetEvalType visitInstruction(Instruction &I)
Value * hasConstantValue() const
If the specified PHI node always merges together the same value, return the value, otherwise return null.
unsigned getNumOperands() const
Definition: User.h:191
Mode EvalMode
How we want to evaluate this object&#39;s size.
This is the shared class of boolean and integer constants.
Definition: Constants.h:83
Evaluate the size and offset of an object pointed to by a Value* statically.
unsigned getParamAlignment() const
If this is a byval or inalloca argument, return its alignment.
Definition: Function.cpp:111
Provides information about what library functions are available for the current target.
SizeOffsetType visitPHINode(PHINode &)
A constant pointer value that points to null.
Definition: Constants.h:538
Type * getReturnType() const
Definition: DerivedTypes.h:123
uint64_t getSizeInBytes() const
Definition: DataLayout.h:570
SizeOffsetType visitUndefValue(UndefValue &)
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:631
unsigned getNumIncomingValues() const
Return the number of incoming edges.
static const Function * getCalledFunction(const Value *V, bool LookThroughBitCast, bool &IsNoBuiltin)
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
SizeOffsetType compute(Value *V)
FunctionType * getFunctionType() const
Returns the FunctionType for me.
Definition: Function.h:163
Class for arbitrary precision integers.
Definition: APInt.h:69
amdgpu Simplify well known AMD library false FunctionCallee Callee
SizeOffsetEvalType visitIntToPtrInst(IntToPtrInst &)
Type * getMallocAllocatedType(const CallInst *CI, const TargetLibraryInfo *TLI)
getMallocAllocatedType - Returns the Type allocated by malloc call.
SizeOffsetEvalType visitPHINode(PHINode &PHI)
bool getLibFunc(StringRef funcName, LibFunc &F) const
Searches for a particular function name.
bool isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
Tests if a value is a call or invoke to a library function that allocates uninitialized memory (such ...
const Value * getFalseValue() const
user_iterator_impl< const User > const_user_iterator
Definition: Value.h:369
Fail to evaluate an unknown condition.
SizeOffsetEvalType compute(Value *V)
uint64_t getTypeAllocSize(Type *Ty) const
Returns the offset in bytes between successive objects of the specified type, including alignment pad...
Definition: DataLayout.h:469
bool ugt(const APInt &RHS) const
Unsigned greather than comparison.
Definition: APInt.h:1254
static bool isZero(Value *V, const DataLayout &DL, DominatorTree *DT, AssumptionCache *AC)
Definition: Lint.cpp:549
Provides an &#39;InsertHelper&#39; that calls a user-provided callback after performing the default insertion...
Definition: IRBuilder.h:72
ObjectSizeOffsetVisitor(const DataLayout &DL, const TargetLibraryInfo *TLI, LLVMContext &Context, ObjectSizeOpts Options={})
SizeOffsetEvalType visitLoadInst(LoadInst &I)
bool isMallocOrCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
Tests if a value is a call or invoke to a library function that allocates memory similar to malloc or...
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:214
Establish a view to a call site for examination.
Definition: CallSite.h:892
BasicBlock * getIncomingBlock(unsigned i) const
Return incoming basic block number i.
bool isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
Tests if a value is a call or invoke to a library function that allocates zero-filled memory (such as...
#define I(x, y, z)
Definition: MD5.cpp:58
PointerType * getType() const
Specialize the getType() method to always return an PointerType, which reduces the amount of casting ...
Definition: Constants.h:554
bool isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI, bool LookThroughBitCast=false)
Tests if a value is a call or invoke to a library function that allocates memory (either malloc...
iterator end()
Definition: DenseMap.h:108
bool ComputeMultiple(Value *V, unsigned Base, Value *&Multiple, bool LookThroughSExt=false, unsigned Depth=0)
This function computes the integer multiple of Base that equals V.
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:332
This instruction extracts a single (scalar) element from a VectorType value.
uint32_t Size
Definition: Profile.cpp:46
bool anyKnown(SizeOffsetEvalType SizeOffset)
APInt umul_ov(const APInt &RHS, bool &Overflow) const
Definition: APInt.cpp:1916
bool isArrayAllocation() const
Return true if there is an allocation size parameter to the allocation instruction that is not 1...
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
user_iterator user_begin()
Definition: Value.h:375
static bool bothKnown(const SizeOffsetType &SizeOffset)
LLVM Value Representation.
Definition: Value.h:72
SizeOffsetEvalType visitExtractElementInst(ExtractElementInst &I)
Attribute getFnAttribute(Attribute::AttrKind Kind) const
Return the attribute for the given attribute kind.
Definition: Function.h:333
AllocType AllocTy
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
Various options to control the behavior of getObjectSize.
static APInt getNullValue(unsigned numBits)
Get the &#39;0&#39; value.
Definition: APInt.h:568
bool isUIntN(unsigned N, uint64_t x)
Checks if an unsigned integer fits into the given (dynamic) bit width.
Definition: MathExtras.h:392
#define LLVM_DEBUG(X)
Definition: Debug.h:122
SizeOffsetType visitLoadInst(LoadInst &I)
SizeOffsetEvalType visitAllocaInst(AllocaInst &I)
bool bothKnown(SizeOffsetEvalType SizeOffset)
SizeOffsetType visitConstantPointerNull(ConstantPointerNull &)
SizeOffsetEvalType visitExtractValueInst(ExtractValueInst &I)
constexpr char Args[]
Key for Kernel::Metadata::mArgs.
Type * getElementType() const
Definition: DerivedTypes.h:517
PointerType * getType() const
Global values are always pointers.
Definition: GlobalValue.h:273
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:43
an instruction to allocate memory on the stack
Definition: Instructions.h:59
user_iterator user_end()
Definition: Value.h:383
const Constant * getAliasee() const
Definition: GlobalAlias.h:77