1 //===------ MemoryBuiltins.cpp - Identify calls to memory builtins --------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This family of functions identifies calls to builtin functions that allocate
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "memory-builtins"
16 #include "llvm/Analysis/MemoryBuiltins.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/Statistic.h"
19 #include "llvm/Analysis/ValueTracking.h"
20 #include "llvm/IR/DataLayout.h"
21 #include "llvm/IR/GlobalVariable.h"
22 #include "llvm/IR/Instructions.h"
23 #include "llvm/IR/Intrinsics.h"
24 #include "llvm/IR/Metadata.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/Support/Debug.h"
27 #include "llvm/Support/MathExtras.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include "llvm/Target/TargetLibraryInfo.h"
30 #include "llvm/Transforms/Utils/Local.h"
34 MallocLike = 1<<0, // allocates
35 CallocLike = 1<<1, // allocates + bzero
36 ReallocLike = 1<<2, // reallocates
38 AllocLike = MallocLike | CallocLike | StrDupLike,
39 AnyAlloc = MallocLike | CallocLike | ReallocLike | StrDupLike
45 unsigned char NumParams;
46 // First and Second size parameters (or -1 if unused)
47 signed char FstParam, SndParam;
50 // FIXME: certain users need more information. E.g., SimplifyLibCalls needs to
51 // know which functions are nounwind, noalias, nocapture parameters, etc.
52 static const AllocFnsTy AllocationFnData[] = {
53 {LibFunc::malloc, MallocLike, 1, 0, -1},
54 {LibFunc::valloc, MallocLike, 1, 0, -1},
55 {LibFunc::Znwj, MallocLike, 1, 0, -1}, // new(unsigned int)
56 {LibFunc::ZnwjRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new(unsigned int, nothrow)
57 {LibFunc::Znwm, MallocLike, 1, 0, -1}, // new(unsigned long)
58 {LibFunc::ZnwmRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new(unsigned long, nothrow)
59 {LibFunc::Znaj, MallocLike, 1, 0, -1}, // new[](unsigned int)
60 {LibFunc::ZnajRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new[](unsigned int, nothrow)
61 {LibFunc::Znam, MallocLike, 1, 0, -1}, // new[](unsigned long)
62 {LibFunc::ZnamRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new[](unsigned long, nothrow)
63 {LibFunc::posix_memalign, MallocLike, 3, 2, -1},
64 {LibFunc::calloc, CallocLike, 2, 0, 1},
65 {LibFunc::realloc, ReallocLike, 2, 1, -1},
66 {LibFunc::reallocf, ReallocLike, 2, 1, -1},
67 {LibFunc::strdup, StrDupLike, 1, -1, -1},
68 {LibFunc::strndup, StrDupLike, 2, 1, -1}
72 static Function *getCalledFunction(const Value *V, bool LookThroughBitCast) {
73 if (LookThroughBitCast)
74 V = V->stripPointerCasts();
76 CallSite CS(const_cast<Value*>(V));
77 if (!CS.getInstruction())
83 Function *Callee = CS.getCalledFunction();
84 if (!Callee || !Callee->isDeclaration())
89 /// \brief Returns the allocation data for the given value if it is a call to a
90 /// known allocation function, and NULL otherwise.
91 static const AllocFnsTy *getAllocationData(const Value *V, AllocType AllocTy,
92 const TargetLibraryInfo *TLI,
93 bool LookThroughBitCast = false) {
95 if (isa<IntrinsicInst>(V))
98 Function *Callee = getCalledFunction(V, LookThroughBitCast);
102 // Make sure that the function is available.
103 StringRef FnName = Callee->getName();
105 if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
110 for ( ; i < array_lengthof(AllocationFnData); ++i) {
111 if (AllocationFnData[i].Func == TLIFn) {
119 const AllocFnsTy *FnData = &AllocationFnData[i];
120 if ((FnData->AllocTy & AllocTy) == 0)
123 // Check function prototype.
124 int FstParam = FnData->FstParam;
125 int SndParam = FnData->SndParam;
126 FunctionType *FTy = Callee->getFunctionType();
128 if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
129 FTy->getNumParams() == FnData->NumParams &&
131 (FTy->getParamType(FstParam)->isIntegerTy(32) ||
132 FTy->getParamType(FstParam)->isIntegerTy(64))) &&
134 FTy->getParamType(SndParam)->isIntegerTy(32) ||
135 FTy->getParamType(SndParam)->isIntegerTy(64)))
140 static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
141 ImmutableCallSite CS(LookThroughBitCast ? V->stripPointerCasts() : V);
142 return CS && CS.hasFnAttr(Attribute::NoAlias);
146 /// \brief Tests if a value is a call or invoke to a library function that
147 /// allocates or reallocates memory (either malloc, calloc, realloc, or strdup
149 bool llvm::isAllocationFn(const Value *V, const TargetLibraryInfo *TLI,
150 bool LookThroughBitCast) {
151 return getAllocationData(V, AnyAlloc, TLI, LookThroughBitCast);
154 /// \brief Tests if a value is a call or invoke to a function that returns a
155 /// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions).
156 bool llvm::isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI,
157 bool LookThroughBitCast) {
158 // it's safe to consider realloc as noalias since accessing the original
159 // pointer is undefined behavior
160 return isAllocationFn(V, TLI, LookThroughBitCast) ||
161 hasNoAliasAttr(V, LookThroughBitCast);
164 /// \brief Tests if a value is a call or invoke to a library function that
165 /// allocates uninitialized memory (such as malloc).
166 bool llvm::isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
167 bool LookThroughBitCast) {
168 return getAllocationData(V, MallocLike, TLI, LookThroughBitCast);
171 /// \brief Tests if a value is a call or invoke to a library function that
172 /// allocates zero-filled memory (such as calloc).
173 bool llvm::isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
174 bool LookThroughBitCast) {
175 return getAllocationData(V, CallocLike, TLI, LookThroughBitCast);
178 /// \brief Tests if a value is a call or invoke to a library function that
179 /// allocates memory (either malloc, calloc, or strdup like).
180 bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
181 bool LookThroughBitCast) {
182 return getAllocationData(V, AllocLike, TLI, LookThroughBitCast);
185 /// \brief Tests if a value is a call or invoke to a library function that
186 /// reallocates memory (such as realloc).
187 bool llvm::isReallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
188 bool LookThroughBitCast) {
189 return getAllocationData(V, ReallocLike, TLI, LookThroughBitCast);
192 /// extractMallocCall - Returns the corresponding CallInst if the instruction
193 /// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
194 /// ignore InvokeInst here.
195 const CallInst *llvm::extractMallocCall(const Value *I,
196 const TargetLibraryInfo *TLI) {
197 return isMallocLikeFn(I, TLI) ? dyn_cast<CallInst>(I) : 0;
200 static Value *computeArraySize(const CallInst *CI, const DataLayout *TD,
201 const TargetLibraryInfo *TLI,
202 bool LookThroughSExt = false) {
206 // The size of the malloc's result type must be known to determine array size.
207 Type *T = getMallocAllocatedType(CI, TLI);
208 if (!T || !T->isSized() || !TD)
211 unsigned ElementSize = TD->getTypeAllocSize(T);
212 if (StructType *ST = dyn_cast<StructType>(T))
213 ElementSize = TD->getStructLayout(ST)->getSizeInBytes();
215 // If malloc call's arg can be determined to be a multiple of ElementSize,
216 // return the multiple. Otherwise, return NULL.
217 Value *MallocArg = CI->getArgOperand(0);
219 if (ComputeMultiple(MallocArg, ElementSize, Multiple,
226 /// isArrayMalloc - Returns the corresponding CallInst if the instruction
227 /// is a call to malloc whose array size can be determined and the array size
228 /// is not constant 1. Otherwise, return NULL.
229 const CallInst *llvm::isArrayMalloc(const Value *I,
230 const DataLayout *TD,
231 const TargetLibraryInfo *TLI) {
232 const CallInst *CI = extractMallocCall(I, TLI);
233 Value *ArraySize = computeArraySize(CI, TD, TLI);
235 if (ConstantInt *ConstSize = dyn_cast_or_null<ConstantInt>(ArraySize))
236 if (ConstSize->isOne())
239 // CI is a non-array malloc or we can't figure out that it is an array malloc.
243 /// getMallocType - Returns the PointerType resulting from the malloc call.
244 /// The PointerType depends on the number of bitcast uses of the malloc call:
245 /// 0: PointerType is the calls' return type.
246 /// 1: PointerType is the bitcast's result type.
247 /// >1: Unique PointerType cannot be determined, return NULL.
248 PointerType *llvm::getMallocType(const CallInst *CI,
249 const TargetLibraryInfo *TLI) {
250 assert(isMallocLikeFn(CI, TLI) && "getMallocType and not malloc call");
252 PointerType *MallocType = 0;
253 unsigned NumOfBitCastUses = 0;
255 // Determine if CallInst has a bitcast use.
256 for (Value::const_use_iterator UI = CI->use_begin(), E = CI->use_end();
258 if (const BitCastInst *BCI = dyn_cast<BitCastInst>(*UI++)) {
259 MallocType = cast<PointerType>(BCI->getDestTy());
263 // Malloc call has 1 bitcast use, so type is the bitcast's destination type.
264 if (NumOfBitCastUses == 1)
267 // Malloc call was not bitcast, so type is the malloc function's return type.
268 if (NumOfBitCastUses == 0)
269 return cast<PointerType>(CI->getType());
271 // Type could not be determined.
275 /// getMallocAllocatedType - Returns the Type allocated by malloc call.
276 /// The Type depends on the number of bitcast uses of the malloc call:
277 /// 0: PointerType is the malloc calls' return type.
278 /// 1: PointerType is the bitcast's result type.
279 /// >1: Unique PointerType cannot be determined, return NULL.
280 Type *llvm::getMallocAllocatedType(const CallInst *CI,
281 const TargetLibraryInfo *TLI) {
282 PointerType *PT = getMallocType(CI, TLI);
283 return PT ? PT->getElementType() : 0;
286 /// getMallocArraySize - Returns the array size of a malloc call. If the
287 /// argument passed to malloc is a multiple of the size of the malloced type,
288 /// then return that multiple. For non-array mallocs, the multiple is
289 /// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
291 Value *llvm::getMallocArraySize(CallInst *CI, const DataLayout *TD,
292 const TargetLibraryInfo *TLI,
293 bool LookThroughSExt) {
294 assert(isMallocLikeFn(CI, TLI) && "getMallocArraySize and not malloc call");
295 return computeArraySize(CI, TD, TLI, LookThroughSExt);
299 /// extractCallocCall - Returns the corresponding CallInst if the instruction
300 /// is a calloc call.
301 const CallInst *llvm::extractCallocCall(const Value *I,
302 const TargetLibraryInfo *TLI) {
303 return isCallocLikeFn(I, TLI) ? cast<CallInst>(I) : 0;
307 /// isFreeCall - Returns non-null if the value is a call to the builtin free()
308 const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
309 const CallInst *CI = dyn_cast<CallInst>(I);
310 if (!CI || isa<IntrinsicInst>(CI))
312 Function *Callee = CI->getCalledFunction();
313 if (Callee == 0 || !Callee->isDeclaration())
316 StringRef FnName = Callee->getName();
318 if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
321 if (TLIFn != LibFunc::free &&
322 TLIFn != LibFunc::ZdlPv && // operator delete(void*)
323 TLIFn != LibFunc::ZdaPv) // operator delete[](void*)
326 // Check free prototype.
327 // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
328 // attribute will exist.
329 FunctionType *FTy = Callee->getFunctionType();
330 if (!FTy->getReturnType()->isVoidTy())
332 if (FTy->getNumParams() != 1)
334 if (FTy->getParamType(0) != Type::getInt8PtrTy(Callee->getContext()))
342 //===----------------------------------------------------------------------===//
343 // Utility functions to compute size of objects.
347 /// \brief Compute the size of the object pointed by Ptr. Returns true and the
348 /// object size in Size if successful, and false otherwise.
349 /// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
350 /// byval arguments, and global variables.
351 bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout *TD,
352 const TargetLibraryInfo *TLI, bool RoundToAlign) {
356 ObjectSizeOffsetVisitor Visitor(TD, TLI, Ptr->getContext(), RoundToAlign);
357 SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
358 if (!Visitor.bothKnown(Data))
361 APInt ObjSize = Data.first, Offset = Data.second;
362 // check for overflow
363 if (Offset.slt(0) || ObjSize.ult(Offset))
366 Size = (ObjSize - Offset).getZExtValue();
371 STATISTIC(ObjectVisitorArgument,
372 "Number of arguments with unsolved size and offset");
373 STATISTIC(ObjectVisitorLoad,
374 "Number of load instructions with unsolved size and offset");
377 APInt ObjectSizeOffsetVisitor::align(APInt Size, uint64_t Align) {
378 if (RoundToAlign && Align)
379 return APInt(IntTyBits, RoundUpToAlignment(Size.getZExtValue(), Align));
383 ObjectSizeOffsetVisitor::ObjectSizeOffsetVisitor(const DataLayout *TD,
384 const TargetLibraryInfo *TLI,
385 LLVMContext &Context,
387 : TD(TD), TLI(TLI), RoundToAlign(RoundToAlign) {
388 IntegerType *IntTy = TD->getIntPtrType(Context);
389 IntTyBits = IntTy->getBitWidth();
390 Zero = APInt::getNullValue(IntTyBits);
393 SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
394 V = V->stripPointerCasts();
395 if (Instruction *I = dyn_cast<Instruction>(V)) {
396 // If we have already seen this instruction, bail out. Cycles can happen in
397 // unreachable code after constant propagation.
398 if (!SeenInsts.insert(I))
401 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
402 return visitGEPOperator(*GEP);
405 if (Argument *A = dyn_cast<Argument>(V))
406 return visitArgument(*A);
407 if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
408 return visitConstantPointerNull(*P);
409 if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
410 return visitGlobalAlias(*GA);
411 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
412 return visitGlobalVariable(*GV);
413 if (UndefValue *UV = dyn_cast<UndefValue>(V))
414 return visitUndefValue(*UV);
415 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
416 if (CE->getOpcode() == Instruction::IntToPtr)
417 return unknown(); // clueless
418 if (CE->getOpcode() == Instruction::GetElementPtr)
419 return visitGEPOperator(cast<GEPOperator>(*CE));
422 DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: " << *V
427 SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
428 if (!I.getAllocatedType()->isSized())
431 APInt Size(IntTyBits, TD->getTypeAllocSize(I.getAllocatedType()));
432 if (!I.isArrayAllocation())
433 return std::make_pair(align(Size, I.getAlignment()), Zero);
435 Value *ArraySize = I.getArraySize();
436 if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
437 Size *= C->getValue().zextOrSelf(IntTyBits);
438 return std::make_pair(align(Size, I.getAlignment()), Zero);
443 SizeOffsetType ObjectSizeOffsetVisitor::visitArgument(Argument &A) {
444 // no interprocedural analysis is done at the moment
445 if (!A.hasByValAttr()) {
446 ++ObjectVisitorArgument;
449 PointerType *PT = cast<PointerType>(A.getType());
450 APInt Size(IntTyBits, TD->getTypeAllocSize(PT->getElementType()));
451 return std::make_pair(align(Size, A.getParamAlignment()), Zero);
454 SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
455 const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc,
460 // handle strdup-like functions separately
461 if (FnData->AllocTy == StrDupLike) {
462 APInt Size(IntTyBits, GetStringLength(CS.getArgument(0)));
466 // strndup limits strlen
467 if (FnData->FstParam > 0) {
468 ConstantInt *Arg= dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
472 APInt MaxSize = Arg->getValue().zextOrSelf(IntTyBits);
473 if (Size.ugt(MaxSize))
476 return std::make_pair(Size, Zero);
479 ConstantInt *Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
483 APInt Size = Arg->getValue().zextOrSelf(IntTyBits);
484 // size determined by just 1 parameter
485 if (FnData->SndParam < 0)
486 return std::make_pair(Size, Zero);
488 Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->SndParam));
492 Size *= Arg->getValue().zextOrSelf(IntTyBits);
493 return std::make_pair(Size, Zero);
495 // TODO: handle more standard functions (+ wchar cousins):
496 // - strdup / strndup
497 // - strcpy / strncpy
498 // - strcat / strncat
499 // - memcpy / memmove
500 // - strcat / strncat
505 ObjectSizeOffsetVisitor::visitConstantPointerNull(ConstantPointerNull&) {
506 return std::make_pair(Zero, Zero);
510 ObjectSizeOffsetVisitor::visitExtractElementInst(ExtractElementInst&) {
515 ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
516 // Easy cases were already folded by previous passes.
520 SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
521 SizeOffsetType PtrData = compute(GEP.getPointerOperand());
522 APInt Offset(IntTyBits, 0);
523 if (!bothKnown(PtrData) || !GEP.accumulateConstantOffset(*TD, Offset))
526 return std::make_pair(PtrData.first, PtrData.second + Offset);
529 SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalAlias(GlobalAlias &GA) {
530 if (GA.mayBeOverridden())
532 return compute(GA.getAliasee());
535 SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
536 if (!GV.hasDefinitiveInitializer())
539 APInt Size(IntTyBits, TD->getTypeAllocSize(GV.getType()->getElementType()));
540 return std::make_pair(align(Size, GV.getAlignment()), Zero);
543 SizeOffsetType ObjectSizeOffsetVisitor::visitIntToPtrInst(IntToPtrInst&) {
548 SizeOffsetType ObjectSizeOffsetVisitor::visitLoadInst(LoadInst&) {
553 SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
554 // too complex to analyze statically.
558 SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
559 SizeOffsetType TrueSide = compute(I.getTrueValue());
560 SizeOffsetType FalseSide = compute(I.getFalseValue());
561 if (bothKnown(TrueSide) && bothKnown(FalseSide) && TrueSide == FalseSide)
566 SizeOffsetType ObjectSizeOffsetVisitor::visitUndefValue(UndefValue&) {
567 return std::make_pair(Zero, Zero);
570 SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
571 DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I << '\n');
576 ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const DataLayout *TD,
577 const TargetLibraryInfo *TLI,
578 LLVMContext &Context)
579 : TD(TD), TLI(TLI), Context(Context), Builder(Context, TargetFolder(TD)) {
580 IntTy = TD->getIntPtrType(Context);
581 Zero = ConstantInt::get(IntTy, 0);
584 SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
585 SizeOffsetEvalType Result = compute_(V);
587 if (!bothKnown(Result)) {
588 // erase everything that was computed in this iteration from the cache, so
589 // that no dangling references are left behind. We could be a bit smarter if
590 // we kept a dependency graph. It's probably not worth the complexity.
591 for (PtrSetTy::iterator I=SeenVals.begin(), E=SeenVals.end(); I != E; ++I) {
592 CacheMapTy::iterator CacheIt = CacheMap.find(*I);
593 // non-computable results can be safely cached
594 if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
595 CacheMap.erase(CacheIt);
603 SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
604 ObjectSizeOffsetVisitor Visitor(TD, TLI, Context);
605 SizeOffsetType Const = Visitor.compute(V);
606 if (Visitor.bothKnown(Const))
607 return std::make_pair(ConstantInt::get(Context, Const.first),
608 ConstantInt::get(Context, Const.second));
610 V = V->stripPointerCasts();
613 CacheMapTy::iterator CacheIt = CacheMap.find(V);
614 if (CacheIt != CacheMap.end())
615 return CacheIt->second;
617 // always generate code immediately before the instruction being
618 // processed, so that the generated code dominates the same BBs
619 Instruction *PrevInsertPoint = Builder.GetInsertPoint();
620 if (Instruction *I = dyn_cast<Instruction>(V))
621 Builder.SetInsertPoint(I);
623 // record the pointers that were handled in this run, so that they can be
624 // cleaned later if something fails
627 // now compute the size and offset
628 SizeOffsetEvalType Result;
629 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
630 Result = visitGEPOperator(*GEP);
631 } else if (Instruction *I = dyn_cast<Instruction>(V)) {
633 } else if (isa<Argument>(V) ||
634 (isa<ConstantExpr>(V) &&
635 cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
636 isa<GlobalAlias>(V) ||
637 isa<GlobalVariable>(V)) {
638 // ignore values where we cannot do more than what ObjectSizeVisitor can
641 DEBUG(dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: "
647 Builder.SetInsertPoint(PrevInsertPoint);
649 // Don't reuse CacheIt since it may be invalid at this point.
650 CacheMap[V] = Result;
654 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
655 if (!I.getAllocatedType()->isSized())
659 assert(I.isArrayAllocation());
660 Value *ArraySize = I.getArraySize();
661 Value *Size = ConstantInt::get(ArraySize->getType(),
662 TD->getTypeAllocSize(I.getAllocatedType()));
663 Size = Builder.CreateMul(Size, ArraySize);
664 return std::make_pair(Size, Zero);
667 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
668 const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc,
673 // handle strdup-like functions separately
674 if (FnData->AllocTy == StrDupLike) {
679 Value *FirstArg = CS.getArgument(FnData->FstParam);
680 FirstArg = Builder.CreateZExt(FirstArg, IntTy);
681 if (FnData->SndParam < 0)
682 return std::make_pair(FirstArg, Zero);
684 Value *SecondArg = CS.getArgument(FnData->SndParam);
685 SecondArg = Builder.CreateZExt(SecondArg, IntTy);
686 Value *Size = Builder.CreateMul(FirstArg, SecondArg);
687 return std::make_pair(Size, Zero);
689 // TODO: handle more standard functions (+ wchar cousins):
690 // - strdup / strndup
691 // - strcpy / strncpy
692 // - strcat / strncat
693 // - memcpy / memmove
694 // - strcat / strncat
699 ObjectSizeOffsetEvaluator::visitExtractElementInst(ExtractElementInst&) {
704 ObjectSizeOffsetEvaluator::visitExtractValueInst(ExtractValueInst&) {
709 ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
710 SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
711 if (!bothKnown(PtrData))
714 Value *Offset = EmitGEPOffset(&Builder, *TD, &GEP, /*NoAssumptions=*/true);
715 Offset = Builder.CreateAdd(PtrData.second, Offset);
716 return std::make_pair(PtrData.first, Offset);
719 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitIntToPtrInst(IntToPtrInst&) {
724 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitLoadInst(LoadInst&) {
728 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
729 // create 2 PHIs: one for size and another for offset
730 PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
731 PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
733 // insert right away in the cache to handle recursive PHIs
734 CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
736 // compute offset/size for each PHI incoming pointer
737 for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
738 Builder.SetInsertPoint(PHI.getIncomingBlock(i)->getFirstInsertionPt());
739 SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
741 if (!bothKnown(EdgeData)) {
742 OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
743 OffsetPHI->eraseFromParent();
744 SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
745 SizePHI->eraseFromParent();
748 SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
749 OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
752 Value *Size = SizePHI, *Offset = OffsetPHI, *Tmp;
753 if ((Tmp = SizePHI->hasConstantValue())) {
755 SizePHI->replaceAllUsesWith(Size);
756 SizePHI->eraseFromParent();
758 if ((Tmp = OffsetPHI->hasConstantValue())) {
760 OffsetPHI->replaceAllUsesWith(Offset);
761 OffsetPHI->eraseFromParent();
763 return std::make_pair(Size, Offset);
766 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
767 SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
768 SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
770 if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
772 if (TrueSide == FalseSide)
775 Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
777 Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
779 return std::make_pair(Size, Offset);
782 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitInstruction(Instruction &I) {
783 DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I <<'\n');