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/ADT/Statistic.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/Analysis/MemoryBuiltins.h"
19 #include "llvm/GlobalVariable.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/Intrinsics.h"
22 #include "llvm/Metadata.h"
23 #include "llvm/Module.h"
24 #include "llvm/Analysis/ValueTracking.h"
25 #include "llvm/Support/Debug.h"
26 #include "llvm/Support/MathExtras.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include "llvm/Target/TargetData.h"
29 #include "llvm/Transforms/Utils/Local.h"
33 MallocLike = 1<<0, // allocates
34 CallocLike = 1<<1, // allocates + bzero
35 ReallocLike = 1<<2, // reallocates
37 AllocLike = MallocLike | CallocLike | StrDupLike,
38 AnyAlloc = MallocLike | CallocLike | ReallocLike | StrDupLike
44 unsigned char NumParams;
45 // First and Second size parameters (or -1 if unused)
46 signed char FstParam, SndParam;
49 // FIXME: certain users need more information. E.g., SimplifyLibCalls needs to
50 // know which functions are nounwind, noalias, nocapture parameters, etc.
51 static const AllocFnsTy AllocationFnData[] = {
52 {"malloc", MallocLike, 1, 0, -1},
53 {"valloc", MallocLike, 1, 0, -1},
54 {"_Znwj", MallocLike, 1, 0, -1}, // new(unsigned int)
55 {"_ZnwjRKSt9nothrow_t", MallocLike, 2, 0, -1}, // new(unsigned int, nothrow)
56 {"_Znwm", MallocLike, 1, 0, -1}, // new(unsigned long)
57 {"_ZnwmRKSt9nothrow_t", MallocLike, 2, 0, -1}, // new(unsigned long, nothrow)
58 {"_Znaj", MallocLike, 1, 0, -1}, // new[](unsigned int)
59 {"_ZnajRKSt9nothrow_t", MallocLike, 2, 0, -1}, // new[](unsigned int, nothrow)
60 {"_Znam", MallocLike, 1, 0, -1}, // new[](unsigned long)
61 {"_ZnamRKSt9nothrow_t", MallocLike, 2, 0, -1}, // new[](unsigned long, nothrow)
62 {"posix_memalign", MallocLike, 3, 2, -1},
63 {"calloc", CallocLike, 2, 0, 1},
64 {"realloc", ReallocLike, 2, 1, -1},
65 {"reallocf", ReallocLike, 2, 1, -1},
66 {"strdup", StrDupLike, 1, -1, -1},
67 {"strndup", StrDupLike, 2, -1, -1}
71 static Function *getCalledFunction(const Value *V, bool LookThroughBitCast) {
72 if (LookThroughBitCast)
73 V = V->stripPointerCasts();
75 CallSite CS(const_cast<Value*>(V));
76 if (!CS.getInstruction())
79 Function *Callee = CS.getCalledFunction();
80 if (!Callee || !Callee->isDeclaration())
85 /// \brief Returns the allocation data for the given value if it is a call to a
86 /// known allocation function, and NULL otherwise.
87 static const AllocFnsTy *getAllocationData(const Value *V, AllocType AllocTy,
88 bool LookThroughBitCast = false) {
89 Function *Callee = getCalledFunction(V, LookThroughBitCast);
95 for ( ; i < array_lengthof(AllocationFnData); ++i) {
96 if (Callee->getName() == AllocationFnData[i].Name) {
104 const AllocFnsTy *FnData = &AllocationFnData[i];
105 if ((FnData->AllocTy & AllocTy) == 0)
108 // Check function prototype.
109 // FIXME: Check the nobuiltin metadata?? (PR5130)
110 int FstParam = FnData->FstParam;
111 int SndParam = FnData->SndParam;
112 FunctionType *FTy = Callee->getFunctionType();
114 if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
115 FTy->getNumParams() == FnData->NumParams &&
117 (FTy->getParamType(FstParam)->isIntegerTy(32) ||
118 FTy->getParamType(FstParam)->isIntegerTy(64))) &&
120 FTy->getParamType(SndParam)->isIntegerTy(32) ||
121 FTy->getParamType(SndParam)->isIntegerTy(64)))
126 static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
127 ImmutableCallSite CS(LookThroughBitCast ? V->stripPointerCasts() : V);
128 return CS && CS.hasFnAttr(Attribute::NoAlias);
132 /// \brief Tests if a value is a call or invoke to a library function that
133 /// allocates or reallocates memory (either malloc, calloc, realloc, or strdup
135 bool llvm::isAllocationFn(const Value *V, bool LookThroughBitCast) {
136 return getAllocationData(V, AnyAlloc, LookThroughBitCast);
139 /// \brief Tests if a value is a call or invoke to a function that returns a
140 /// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions).
141 bool llvm::isNoAliasFn(const Value *V, bool LookThroughBitCast) {
142 // it's safe to consider realloc as noalias since accessing the original
143 // pointer is undefined behavior
144 return isAllocationFn(V, LookThroughBitCast) ||
145 hasNoAliasAttr(V, LookThroughBitCast);
148 /// \brief Tests if a value is a call or invoke to a library function that
149 /// allocates uninitialized memory (such as malloc).
150 bool llvm::isMallocLikeFn(const Value *V, bool LookThroughBitCast) {
151 return getAllocationData(V, MallocLike, LookThroughBitCast);
154 /// \brief Tests if a value is a call or invoke to a library function that
155 /// allocates zero-filled memory (such as calloc).
156 bool llvm::isCallocLikeFn(const Value *V, bool LookThroughBitCast) {
157 return getAllocationData(V, CallocLike, LookThroughBitCast);
160 /// \brief Tests if a value is a call or invoke to a library function that
161 /// allocates memory (either malloc, calloc, or strdup like).
162 bool llvm::isAllocLikeFn(const Value *V, bool LookThroughBitCast) {
163 return getAllocationData(V, AllocLike, LookThroughBitCast);
166 /// \brief Tests if a value is a call or invoke to a library function that
167 /// reallocates memory (such as realloc).
168 bool llvm::isReallocLikeFn(const Value *V, bool LookThroughBitCast) {
169 return getAllocationData(V, ReallocLike, LookThroughBitCast);
172 /// extractMallocCall - Returns the corresponding CallInst if the instruction
173 /// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
174 /// ignore InvokeInst here.
175 const CallInst *llvm::extractMallocCall(const Value *I) {
176 return isMallocLikeFn(I) ? dyn_cast<CallInst>(I) : 0;
179 static Value *computeArraySize(const CallInst *CI, const TargetData *TD,
180 bool LookThroughSExt = false) {
184 // The size of the malloc's result type must be known to determine array size.
185 Type *T = getMallocAllocatedType(CI);
186 if (!T || !T->isSized() || !TD)
189 unsigned ElementSize = TD->getTypeAllocSize(T);
190 if (StructType *ST = dyn_cast<StructType>(T))
191 ElementSize = TD->getStructLayout(ST)->getSizeInBytes();
193 // If malloc call's arg can be determined to be a multiple of ElementSize,
194 // return the multiple. Otherwise, return NULL.
195 Value *MallocArg = CI->getArgOperand(0);
196 Value *Multiple = NULL;
197 if (ComputeMultiple(MallocArg, ElementSize, Multiple,
204 /// isArrayMalloc - Returns the corresponding CallInst if the instruction
205 /// is a call to malloc whose array size can be determined and the array size
206 /// is not constant 1. Otherwise, return NULL.
207 const CallInst *llvm::isArrayMalloc(const Value *I, const TargetData *TD) {
208 const CallInst *CI = extractMallocCall(I);
209 Value *ArraySize = computeArraySize(CI, TD);
212 ArraySize != ConstantInt::get(CI->getArgOperand(0)->getType(), 1))
215 // CI is a non-array malloc or we can't figure out that it is an array malloc.
219 /// getMallocType - Returns the PointerType resulting from the malloc call.
220 /// The PointerType depends on the number of bitcast uses of the malloc call:
221 /// 0: PointerType is the calls' return type.
222 /// 1: PointerType is the bitcast's result type.
223 /// >1: Unique PointerType cannot be determined, return NULL.
224 PointerType *llvm::getMallocType(const CallInst *CI) {
225 assert(isMallocLikeFn(CI) && "getMallocType and not malloc call");
227 PointerType *MallocType = NULL;
228 unsigned NumOfBitCastUses = 0;
230 // Determine if CallInst has a bitcast use.
231 for (Value::const_use_iterator UI = CI->use_begin(), E = CI->use_end();
233 if (const BitCastInst *BCI = dyn_cast<BitCastInst>(*UI++)) {
234 MallocType = cast<PointerType>(BCI->getDestTy());
238 // Malloc call has 1 bitcast use, so type is the bitcast's destination type.
239 if (NumOfBitCastUses == 1)
242 // Malloc call was not bitcast, so type is the malloc function's return type.
243 if (NumOfBitCastUses == 0)
244 return cast<PointerType>(CI->getType());
246 // Type could not be determined.
250 /// getMallocAllocatedType - Returns the Type allocated by malloc call.
251 /// The Type depends on the number of bitcast uses of the malloc call:
252 /// 0: PointerType is the malloc calls' return type.
253 /// 1: PointerType is the bitcast's result type.
254 /// >1: Unique PointerType cannot be determined, return NULL.
255 Type *llvm::getMallocAllocatedType(const CallInst *CI) {
256 PointerType *PT = getMallocType(CI);
257 return PT ? PT->getElementType() : NULL;
260 /// getMallocArraySize - Returns the array size of a malloc call. If the
261 /// argument passed to malloc is a multiple of the size of the malloced type,
262 /// then return that multiple. For non-array mallocs, the multiple is
263 /// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
265 Value *llvm::getMallocArraySize(CallInst *CI, const TargetData *TD,
266 bool LookThroughSExt) {
267 assert(isMallocLikeFn(CI) && "getMallocArraySize and not malloc call");
268 return computeArraySize(CI, TD, LookThroughSExt);
272 /// extractCallocCall - Returns the corresponding CallInst if the instruction
273 /// is a calloc call.
274 const CallInst *llvm::extractCallocCall(const Value *I) {
275 return isCallocLikeFn(I) ? cast<CallInst>(I) : 0;
279 /// isFreeCall - Returns non-null if the value is a call to the builtin free()
280 const CallInst *llvm::isFreeCall(const Value *I) {
281 const CallInst *CI = dyn_cast<CallInst>(I);
284 Function *Callee = CI->getCalledFunction();
285 if (Callee == 0 || !Callee->isDeclaration())
288 if (Callee->getName() != "free" &&
289 Callee->getName() != "_ZdlPv" && // operator delete(void*)
290 Callee->getName() != "_ZdaPv") // operator delete[](void*)
293 // Check free prototype.
294 // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
295 // attribute will exist.
296 FunctionType *FTy = Callee->getFunctionType();
297 if (!FTy->getReturnType()->isVoidTy())
299 if (FTy->getNumParams() != 1)
301 if (FTy->getParamType(0) != Type::getInt8PtrTy(Callee->getContext()))
309 //===----------------------------------------------------------------------===//
310 // Utility functions to compute size of objects.
314 /// \brief Compute the size of the object pointed by Ptr. Returns true and the
315 /// object size in Size if successful, and false otherwise.
316 /// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
317 /// byval arguments, and global variables.
318 bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const TargetData *TD,
323 ObjectSizeOffsetVisitor Visitor(TD, Ptr->getContext(), RoundToAlign);
324 SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
325 if (!Visitor.bothKnown(Data))
328 APInt ObjSize = Data.first, Offset = Data.second;
329 // check for overflow
330 if (Offset.slt(0) || ObjSize.ult(Offset))
333 Size = (ObjSize - Offset).getZExtValue();
338 STATISTIC(ObjectVisitorArgument,
339 "Number of arguments with unsolved size and offset");
340 STATISTIC(ObjectVisitorLoad,
341 "Number of load instructions with unsolved size and offset");
344 APInt ObjectSizeOffsetVisitor::align(APInt Size, uint64_t Align) {
345 if (RoundToAlign && Align)
346 return APInt(IntTyBits, RoundUpToAlignment(Size.getZExtValue(), Align));
350 ObjectSizeOffsetVisitor::ObjectSizeOffsetVisitor(const TargetData *TD,
351 LLVMContext &Context,
353 : TD(TD), RoundToAlign(RoundToAlign) {
354 IntegerType *IntTy = TD->getIntPtrType(Context);
355 IntTyBits = IntTy->getBitWidth();
356 Zero = APInt::getNullValue(IntTyBits);
359 SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
360 V = V->stripPointerCasts();
362 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
363 return visitGEPOperator(*GEP);
364 if (Instruction *I = dyn_cast<Instruction>(V))
366 if (Argument *A = dyn_cast<Argument>(V))
367 return visitArgument(*A);
368 if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
369 return visitConstantPointerNull(*P);
370 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
371 return visitGlobalVariable(*GV);
372 if (UndefValue *UV = dyn_cast<UndefValue>(V))
373 return visitUndefValue(*UV);
374 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
375 if (CE->getOpcode() == Instruction::IntToPtr)
376 return unknown(); // clueless
378 DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: " << *V
383 SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
384 if (!I.getAllocatedType()->isSized())
387 APInt Size(IntTyBits, TD->getTypeAllocSize(I.getAllocatedType()));
388 if (!I.isArrayAllocation())
389 return std::make_pair(align(Size, I.getAlignment()), Zero);
391 Value *ArraySize = I.getArraySize();
392 if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
393 Size *= C->getValue().zextOrSelf(IntTyBits);
394 return std::make_pair(align(Size, I.getAlignment()), Zero);
399 SizeOffsetType ObjectSizeOffsetVisitor::visitArgument(Argument &A) {
400 // no interprocedural analysis is done at the moment
401 if (!A.hasByValAttr()) {
402 ++ObjectVisitorArgument;
405 PointerType *PT = cast<PointerType>(A.getType());
406 APInt Size(IntTyBits, TD->getTypeAllocSize(PT->getElementType()));
407 return std::make_pair(align(Size, A.getParamAlignment()), Zero);
410 SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
411 const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc);
415 // handle strdup-like functions separately
416 if (FnData->AllocTy == StrDupLike) {
421 ConstantInt *Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
425 APInt Size = Arg->getValue().zextOrSelf(IntTyBits);
426 // size determined by just 1 parameter
427 if (FnData->SndParam < 0)
428 return std::make_pair(Size, Zero);
430 Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->SndParam));
434 Size *= Arg->getValue().zextOrSelf(IntTyBits);
435 return std::make_pair(Size, Zero);
437 // TODO: handle more standard functions (+ wchar cousins):
438 // - strdup / strndup
439 // - strcpy / strncpy
440 // - strcat / strncat
441 // - memcpy / memmove
442 // - strcat / strncat
447 ObjectSizeOffsetVisitor::visitConstantPointerNull(ConstantPointerNull&) {
448 return std::make_pair(Zero, Zero);
452 ObjectSizeOffsetVisitor::visitExtractElementInst(ExtractElementInst&) {
457 ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
458 // Easy cases were already folded by previous passes.
462 SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
463 SizeOffsetType PtrData = compute(GEP.getPointerOperand());
464 if (!bothKnown(PtrData) || !GEP.hasAllConstantIndices())
467 SmallVector<Value*, 8> Ops(GEP.idx_begin(), GEP.idx_end());
468 APInt Offset(IntTyBits,TD->getIndexedOffset(GEP.getPointerOperandType(),Ops));
469 return std::make_pair(PtrData.first, PtrData.second + Offset);
472 SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
473 if (!GV.hasDefinitiveInitializer())
476 APInt Size(IntTyBits, TD->getTypeAllocSize(GV.getType()->getElementType()));
477 return std::make_pair(align(Size, GV.getAlignment()), Zero);
480 SizeOffsetType ObjectSizeOffsetVisitor::visitIntToPtrInst(IntToPtrInst&) {
485 SizeOffsetType ObjectSizeOffsetVisitor::visitLoadInst(LoadInst&) {
490 SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
491 // too complex to analyze statically.
495 SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
496 SizeOffsetType TrueSide = compute(I.getTrueValue());
497 SizeOffsetType FalseSide = compute(I.getFalseValue());
498 if (bothKnown(TrueSide) && bothKnown(FalseSide) && TrueSide == FalseSide)
503 SizeOffsetType ObjectSizeOffsetVisitor::visitUndefValue(UndefValue&) {
504 return std::make_pair(Zero, Zero);
507 SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
508 DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I << '\n');
513 ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const TargetData *TD,
514 LLVMContext &Context)
515 : TD(TD), Context(Context), Builder(Context, TargetFolder(TD)),
516 Visitor(TD, Context) {
517 IntTy = TD->getIntPtrType(Context);
518 Zero = ConstantInt::get(IntTy, 0);
521 SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
522 SizeOffsetEvalType Result = compute_(V);
524 if (!bothKnown(Result)) {
525 // erase everything that was computed in this iteration from the cache, so
526 // that no dangling references are left behind. We could be a bit smarter if
527 // we kept a dependency graph. It's probably not worth the complexity.
528 for (PtrSetTy::iterator I=SeenVals.begin(), E=SeenVals.end(); I != E; ++I) {
529 CacheMapTy::iterator CacheIt = CacheMap.find(*I);
530 // non-computable results can be safely cached
531 if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
532 CacheMap.erase(CacheIt);
540 SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
541 SizeOffsetType Const = Visitor.compute(V);
542 if (Visitor.bothKnown(Const))
543 return std::make_pair(ConstantInt::get(Context, Const.first),
544 ConstantInt::get(Context, Const.second));
546 V = V->stripPointerCasts();
549 CacheMapTy::iterator CacheIt = CacheMap.find(V);
550 if (CacheIt != CacheMap.end())
551 return CacheIt->second;
553 // always generate code immediately before the instruction being
554 // processed, so that the generated code dominates the same BBs
555 Instruction *PrevInsertPoint = Builder.GetInsertPoint();
556 if (Instruction *I = dyn_cast<Instruction>(V))
557 Builder.SetInsertPoint(I);
559 // record the pointers that were handled in this run, so that they can be
560 // cleaned later if something fails
563 // now compute the size and offset
564 SizeOffsetEvalType Result;
565 if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
566 Result = visitGEPOperator(*GEP);
567 } else if (Instruction *I = dyn_cast<Instruction>(V)) {
569 } else if (isa<Argument>(V) ||
570 (isa<ConstantExpr>(V) &&
571 cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
572 isa<GlobalVariable>(V)) {
573 // ignore values where we cannot do more than what ObjectSizeVisitor can
576 DEBUG(dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: "
582 Builder.SetInsertPoint(PrevInsertPoint);
584 // Don't reuse CacheIt since it may be invalid at this point.
585 CacheMap[V] = Result;
589 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
590 if (!I.getAllocatedType()->isSized())
594 assert(I.isArrayAllocation());
595 Value *ArraySize = I.getArraySize();
596 Value *Size = ConstantInt::get(ArraySize->getType(),
597 TD->getTypeAllocSize(I.getAllocatedType()));
598 Size = Builder.CreateMul(Size, ArraySize);
599 return std::make_pair(Size, Zero);
602 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
603 const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc);
607 // handle strdup-like functions separately
608 if (FnData->AllocTy == StrDupLike) {
613 Value *FirstArg = CS.getArgument(FnData->FstParam);
614 FirstArg = Builder.CreateZExt(FirstArg, IntTy);
615 if (FnData->SndParam < 0)
616 return std::make_pair(FirstArg, Zero);
618 Value *SecondArg = CS.getArgument(FnData->SndParam);
619 SecondArg = Builder.CreateZExt(SecondArg, IntTy);
620 Value *Size = Builder.CreateMul(FirstArg, SecondArg);
621 return std::make_pair(Size, Zero);
623 // TODO: handle more standard functions (+ wchar cousins):
624 // - strdup / strndup
625 // - strcpy / strncpy
626 // - strcat / strncat
627 // - memcpy / memmove
628 // - strcat / strncat
633 ObjectSizeOffsetEvaluator::visitExtractElementInst(ExtractElementInst&) {
638 ObjectSizeOffsetEvaluator::visitExtractValueInst(ExtractValueInst&) {
643 ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
644 SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
645 if (!bothKnown(PtrData))
648 Value *Offset = EmitGEPOffset(&Builder, *TD, &GEP, /*NoAssumptions=*/true);
649 Offset = Builder.CreateAdd(PtrData.second, Offset);
650 return std::make_pair(PtrData.first, Offset);
653 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitIntToPtrInst(IntToPtrInst&) {
658 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitLoadInst(LoadInst&) {
662 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
663 // create 2 PHIs: one for size and another for offset
664 PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
665 PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
667 // insert right away in the cache to handle recursive PHIs
668 CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
670 // compute offset/size for each PHI incoming pointer
671 for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
672 Builder.SetInsertPoint(PHI.getIncomingBlock(i)->getFirstInsertionPt());
673 SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
675 if (!bothKnown(EdgeData)) {
676 OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
677 OffsetPHI->eraseFromParent();
678 SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
679 SizePHI->eraseFromParent();
682 SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
683 OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
686 Value *Size = SizePHI, *Offset = OffsetPHI, *Tmp;
687 if ((Tmp = SizePHI->hasConstantValue())) {
689 SizePHI->replaceAllUsesWith(Size);
690 SizePHI->eraseFromParent();
692 if ((Tmp = OffsetPHI->hasConstantValue())) {
694 OffsetPHI->replaceAllUsesWith(Offset);
695 OffsetPHI->eraseFromParent();
697 return std::make_pair(Size, Offset);
700 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
701 SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
702 SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
704 if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
706 if (TrueSide == FalseSide)
709 Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
711 Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
713 return std::make_pair(Size, Offset);
716 SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitInstruction(Instruction &I) {
717 DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I <<'\n');