refactor the MemoryBuiltin analysis:
- provide more extensive set of functions to detect library allocation functions (e.g., malloc, calloc, strdup, etc)
- provide an API to compute the size and offset of an object pointed by
Move a few clients (GVN, AA, instcombine, ...) to the new API.
This implementation is a lot more aggressive than each of the custom implementations being replaced.
Patch reviewed by Nick Lewycky and Chandler Carruth, thanks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158919 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index 9695ae1..2a1afdc 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -12,80 +12,165 @@
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "memory-builtins"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/MemoryBuiltins.h"
-#include "llvm/Constants.h"
+#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Metadata.h"
#include "llvm/Module.h"
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
-//===----------------------------------------------------------------------===//
-// malloc Call Utility Functions.
-//
+enum AllocType {
+ MallocLike = 1<<0, // allocates
+ CallocLike = 1<<1, // allocates + bzero
+ ReallocLike = 1<<2, // reallocates
+ StrDupLike = 1<<3,
+ AllocLike = MallocLike | CallocLike | StrDupLike,
+ AnyAlloc = MallocLike | CallocLike | ReallocLike | StrDupLike
+};
-/// isMalloc - Returns true if the value is either a malloc call or a
-/// bitcast of the result of a malloc call.
-bool llvm::isMalloc(const Value *I) {
- return extractMallocCall(I) || extractMallocCallFromBitCast(I);
-}
+struct AllocFnsTy {
+ const char *Name;
+ AllocType AllocTy;
+ unsigned char NumParams;
+ // First and Second size parameters (or -1 if unused)
+ unsigned char FstParam, SndParam;
+};
-static bool isMallocCall(const CallInst *CI) {
+static const AllocFnsTy AllocationFnData[] = {
+ {"malloc", MallocLike, 1, 0, -1},
+ {"valloc", MallocLike, 1, 0, -1},
+ {"_Znwj", MallocLike, 1, 0, -1}, // operator new(unsigned int)
+ {"_Znwm", MallocLike, 1, 0, -1}, // operator new(unsigned long)
+ {"_Znaj", MallocLike, 1, 0, -1}, // operator new[](unsigned int)
+ {"_Znam", MallocLike, 1, 0, -1}, // operator new[](unsigned long)
+ {"posix_memalign", MallocLike, 3, 2, -1},
+ {"calloc", CallocLike, 2, 0, 1},
+ {"realloc", ReallocLike, 2, 1, -1},
+ {"reallocf", ReallocLike, 2, 1, -1},
+ {"strdup", StrDupLike, 1, -1, -1},
+ {"strndup", StrDupLike, 2, -1, -1}
+};
+
+
+static Function *getCalledFunction(const Value *V, bool LookThroughBitCast) {
+ if (LookThroughBitCast)
+ V = V->stripPointerCasts();
+ const CallInst *CI = dyn_cast<CallInst>(V);
if (!CI)
- return false;
+ return 0;
Function *Callee = CI->getCalledFunction();
- if (Callee == 0 || !Callee->isDeclaration())
- return false;
- if (Callee->getName() != "malloc" &&
- Callee->getName() != "_Znwj" && // operator new(unsigned int)
- Callee->getName() != "_Znwm" && // operator new(unsigned long)
- Callee->getName() != "_Znaj" && // operator new[](unsigned int)
- Callee->getName() != "_Znam") // operator new[](unsigned long)
- return false;
+ if (!Callee || !Callee->isDeclaration())
+ return 0;
+ return Callee;
+}
- // Check malloc prototype.
- // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
- // attribute will exist.
+/// \brief Returns the allocation data for the given value if it is a call to a
+/// known allocation function, and NULL otherwise.
+static const AllocFnsTy *getAllocationData(const Value *V, AllocType AllocTy,
+ bool LookThroughBitCast = false) {
+ Function *Callee = getCalledFunction(V, LookThroughBitCast);
+ if (!Callee)
+ return 0;
+
+ unsigned i = 0;
+ bool found = false;
+ for ( ; i < array_lengthof(AllocationFnData); ++i) {
+ if (Callee->getName() == AllocationFnData[i].Name) {
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ return 0;
+
+ const AllocFnsTy *FnData = &AllocationFnData[i];
+ if ((FnData->AllocTy & AllocTy) == 0)
+ return 0;
+
+ // Check function prototype.
+ // FIXME: Check the nobuiltin metadata?? (PR5130)
+ unsigned FstParam = FnData->FstParam;
+ unsigned SndParam = FnData->SndParam;
FunctionType *FTy = Callee->getFunctionType();
- return FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
- FTy->getNumParams() == 1 &&
- (FTy->getParamType(0)->isIntegerTy(32) ||
- FTy->getParamType(0)->isIntegerTy(64));
+
+ if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
+ FTy->getNumParams() == FnData->NumParams &&
+ (FstParam == (unsigned char)-1 ||
+ (FTy->getParamType(FstParam)->isIntegerTy(32) ||
+ FTy->getParamType(FstParam)->isIntegerTy(64))) &&
+ (SndParam == (unsigned char)-1 ||
+ FTy->getParamType(SndParam)->isIntegerTy(32) ||
+ FTy->getParamType(SndParam)->isIntegerTy(64)))
+ return FnData;
+ return 0;
+}
+
+static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
+ Function *Callee = getCalledFunction(V, LookThroughBitCast);
+ return Callee && Callee->hasFnAttr(Attribute::NoAlias);
+}
+
+
+/// \brief Tests if a value is a call to a library function that allocates or
+/// reallocates memory (either malloc, calloc, realloc, or strdup like).
+bool llvm::isAllocationFn(const Value *V, bool LookThroughBitCast) {
+ return getAllocationData(V, AnyAlloc, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call to a function that returns a NoAlias
+/// pointer (including malloc/calloc/strdup-like functions).
+bool llvm::isNoAliasFn(const Value *V, bool LookThroughBitCast) {
+ return isAllocLikeFn(V, LookThroughBitCast) ||
+ hasNoAliasAttr(V, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call to a library function that allocates
+/// uninitialized memory (such as malloc).
+bool llvm::isMallocLikeFn(const Value *V, bool LookThroughBitCast) {
+ return getAllocationData(V, MallocLike, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call to a library function that allocates
+/// zero-filled memory (such as calloc).
+bool llvm::isCallocLikeFn(const Value *V, bool LookThroughBitCast) {
+ return getAllocationData(V, CallocLike, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call to a library function that allocates
+/// memory (either malloc, calloc, or strdup like).
+bool llvm::isAllocLikeFn(const Value *V, bool LookThroughBitCast) {
+ return getAllocationData(V, AllocLike, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call to a library function that reallocates
+/// memory (such as realloc).
+bool llvm::isReallocLikeFn(const Value *V, bool LookThroughBitCast) {
+ return getAllocationData(V, ReallocLike, LookThroughBitCast);
}
/// extractMallocCall - Returns the corresponding CallInst if the instruction
/// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
/// ignore InvokeInst here.
const CallInst *llvm::extractMallocCall(const Value *I) {
- const CallInst *CI = dyn_cast<CallInst>(I);
- return (isMallocCall(CI)) ? CI : NULL;
-}
-
-CallInst *llvm::extractMallocCall(Value *I) {
- CallInst *CI = dyn_cast<CallInst>(I);
- return (isMallocCall(CI)) ? CI : NULL;
-}
-
-static bool isBitCastOfMallocCall(const BitCastInst *BCI) {
- if (!BCI)
- return false;
-
- return isMallocCall(dyn_cast<CallInst>(BCI->getOperand(0)));
+ return isMallocLikeFn(I) ? cast<CallInst>(I) : 0;
}
/// extractMallocCallFromBitCast - Returns the corresponding CallInst if the
/// instruction is a bitcast of the result of a malloc call.
-CallInst *llvm::extractMallocCallFromBitCast(Value *I) {
- BitCastInst *BCI = dyn_cast<BitCastInst>(I);
- return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
- : NULL;
-}
-
const CallInst *llvm::extractMallocCallFromBitCast(const Value *I) {
const BitCastInst *BCI = dyn_cast<BitCastInst>(I);
- return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
- : NULL;
+ return BCI ? extractMallocCall(BCI->getOperand(0)) : 0;
}
static Value *computeArraySize(const CallInst *CI, const TargetData *TD,
@@ -134,7 +219,7 @@
/// 1: PointerType is the bitcast's result type.
/// >1: Unique PointerType cannot be determined, return NULL.
PointerType *llvm::getMallocType(const CallInst *CI) {
- assert(isMalloc(CI) && "getMallocType and not malloc call");
+ assert(isMallocLikeFn(CI) && "getMallocType and not malloc call");
PointerType *MallocType = NULL;
unsigned NumOfBitCastUses = 0;
@@ -176,53 +261,17 @@
/// determined.
Value *llvm::getMallocArraySize(CallInst *CI, const TargetData *TD,
bool LookThroughSExt) {
- assert(isMalloc(CI) && "getMallocArraySize and not malloc call");
+ assert(isMallocLikeFn(CI) && "getMallocArraySize and not malloc call");
return computeArraySize(CI, TD, LookThroughSExt);
}
-//===----------------------------------------------------------------------===//
-// calloc Call Utility Functions.
-//
-
-static bool isCallocCall(const CallInst *CI) {
- if (!CI)
- return false;
-
- Function *Callee = CI->getCalledFunction();
- if (Callee == 0 || !Callee->isDeclaration())
- return false;
- if (Callee->getName() != "calloc")
- return false;
-
- // Check malloc prototype.
- // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
- // attribute exists.
- FunctionType *FTy = Callee->getFunctionType();
- return FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
- FTy->getNumParams() == 2 &&
- ((FTy->getParamType(0)->isIntegerTy(32) &&
- FTy->getParamType(1)->isIntegerTy(32)) ||
- (FTy->getParamType(0)->isIntegerTy(64) &&
- FTy->getParamType(1)->isIntegerTy(64)));
-}
-
/// extractCallocCall - Returns the corresponding CallInst if the instruction
/// is a calloc call.
const CallInst *llvm::extractCallocCall(const Value *I) {
- const CallInst *CI = dyn_cast<CallInst>(I);
- return isCallocCall(CI) ? CI : 0;
+ return isCallocLikeFn(I) ? cast<CallInst>(I) : 0;
}
-CallInst *llvm::extractCallocCall(Value *I) {
- CallInst *CI = dyn_cast<CallInst>(I);
- return isCallocCall(CI) ? CI : 0;
-}
-
-
-//===----------------------------------------------------------------------===//
-// free Call Utility Functions.
-//
/// isFreeCall - Returns non-null if the value is a call to the builtin free()
const CallInst *llvm::isFreeCall(const Value *I) {
@@ -251,3 +300,388 @@
return CI;
}
+
+
+
+//===----------------------------------------------------------------------===//
+// Utility functions to compute size of objects.
+//
+
+
+/// \brief Compute the size of the object pointed by Ptr. Returns true and the
+/// object size in Size if successful, and false otherwise.
+/// If RoundToAlign is true, then Size is rounded up to the aligment of allocas,
+/// byval arguments, and global variables.
+bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const TargetData *TD,
+ bool RoundToAlign) {
+ if (!TD)
+ return false;
+
+ ObjectSizeOffsetVisitor Visitor(TD, Ptr->getContext(), RoundToAlign);
+ SizeOffsetType Data = Visitor.compute(const_cast<Value*>(Ptr));
+ if (!Visitor.bothKnown(Data))
+ return false;
+
+ APInt ObjSize = Data.first, Offset = Data.second;
+ // check for overflow
+ if (Offset.slt(0) || ObjSize.ult(Offset))
+ Size = 0;
+ else
+ Size = (ObjSize - Offset).getZExtValue();
+ return true;
+}
+
+
+STATISTIC(ObjectVisitorArgument,
+ "Number of arguments with unsolved size and offset");
+STATISTIC(ObjectVisitorLoad,
+ "Number of load instructions with unsolved size and offset");
+
+
+APInt ObjectSizeOffsetVisitor::align(APInt Size, uint64_t Align) {
+ if (RoundToAlign && Align)
+ return APInt(IntTyBits, RoundUpToAlignment(Size.getZExtValue(), Align));
+ return Size;
+}
+
+ObjectSizeOffsetVisitor::ObjectSizeOffsetVisitor(const TargetData *TD,
+ LLVMContext &Context,
+ bool RoundToAlign)
+: TD(TD), RoundToAlign(RoundToAlign) {
+ IntegerType *IntTy = TD->getIntPtrType(Context);
+ IntTyBits = IntTy->getBitWidth();
+ Zero = APInt::getNullValue(IntTyBits);
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
+ V = V->stripPointerCasts();
+
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
+ return visitGEPOperator(*GEP);
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ return visit(*I);
+ if (Argument *A = dyn_cast<Argument>(V))
+ return visitArgument(*A);
+ if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
+ return visitConstantPointerNull(*P);
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
+ return visitGlobalVariable(*GV);
+ if (UndefValue *UV = dyn_cast<UndefValue>(V))
+ return visitUndefValue(*UV);
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
+ if (CE->getOpcode() == Instruction::IntToPtr)
+ return unknown(); // clueless
+
+ DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: " << *V
+ << '\n');
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
+ if (!I.getAllocatedType()->isSized())
+ return unknown();
+
+ APInt Size(IntTyBits, TD->getTypeAllocSize(I.getAllocatedType()));
+ if (!I.isArrayAllocation())
+ return std::make_pair(align(Size, I.getAlignment()), Zero);
+
+ Value *ArraySize = I.getArraySize();
+ if (const ConstantInt *C = dyn_cast<ConstantInt>(ArraySize)) {
+ Size *= C->getValue().zextOrSelf(IntTyBits);
+ return std::make_pair(align(Size, I.getAlignment()), Zero);
+ }
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitArgument(Argument &A) {
+ // no interprocedural analysis is done at the moment
+ if (!A.hasByValAttr()) {
+ ++ObjectVisitorArgument;
+ return unknown();
+ }
+ PointerType *PT = cast<PointerType>(A.getType());
+ APInt Size(IntTyBits, TD->getTypeAllocSize(PT->getElementType()));
+ return std::make_pair(align(Size, A.getParamAlignment()), Zero);
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
+ const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc);
+ if (!FnData)
+ return unknown();
+
+ // handle strdup-like functions separately
+ if (FnData->AllocTy == StrDupLike) {
+ // TODO
+ return unknown();
+ }
+
+ ConstantInt *Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
+ if (!Arg)
+ return unknown();
+
+ APInt Size = Arg->getValue();
+ // size determined by just 1 parameter
+ if (FnData->SndParam == (unsigned char)-1)
+ return std::make_pair(Size, Zero);
+
+ Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->SndParam));
+ if (!Arg)
+ return unknown();
+
+ Size *= Arg->getValue();
+ return std::make_pair(Size, Zero);
+
+ // TODO: handle more standard functions (+ wchar cousins):
+ // - strdup / strndup
+ // - strcpy / strncpy
+ // - strcat / strncat
+ // - memcpy / memmove
+ // - strcat / strncat
+ // - memset
+}
+
+SizeOffsetType
+ObjectSizeOffsetVisitor::visitConstantPointerNull(ConstantPointerNull&) {
+ return std::make_pair(Zero, Zero);
+}
+
+SizeOffsetType
+ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
+ // Easy cases were already folded by previous passes.
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
+ SizeOffsetType PtrData = compute(GEP.getPointerOperand());
+ if (!bothKnown(PtrData) || !GEP.hasAllConstantIndices())
+ return unknown();
+
+ SmallVector<Value*, 8> Ops(GEP.idx_begin(), GEP.idx_end());
+ APInt Offset(IntTyBits,TD->getIndexedOffset(GEP.getPointerOperandType(),Ops));
+ return std::make_pair(PtrData.first, PtrData.second + Offset);
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
+ if (!GV.hasDefinitiveInitializer())
+ return unknown();
+
+ APInt Size(IntTyBits, TD->getTypeAllocSize(GV.getType()->getElementType()));
+ return std::make_pair(align(Size, GV.getAlignment()), Zero);
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitIntToPtrInst(IntToPtrInst&) {
+ // clueless
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitLoadInst(LoadInst&) {
+ ++ObjectVisitorLoad;
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitPHINode(PHINode&) {
+ // too complex to analyze statically.
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
+ SizeOffsetType TrueSide = compute(I.getTrueValue());
+ SizeOffsetType FalseSide = compute(I.getFalseValue());
+ if (bothKnown(TrueSide) && bothKnown(FalseSide) && TrueSide == FalseSide)
+ return TrueSide;
+ return unknown();
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitUndefValue(UndefValue&) {
+ return std::make_pair(Zero, Zero);
+}
+
+SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
+ DEBUG(dbgs() << "ObjectSizeOffsetVisitor unknown instruction:" << I << '\n');
+ return unknown();
+}
+
+
+ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const TargetData *TD,
+ LLVMContext &Context)
+: TD(TD), Context(Context), Builder(Context, TargetFolder(TD)),
+Visitor(TD, Context) {
+ IntTy = TD->getIntPtrType(Context);
+ Zero = ConstantInt::get(IntTy, 0);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
+ SizeOffsetEvalType Result = compute_(V);
+
+ if (!bothKnown(Result)) {
+ // erase everything that was computed in this iteration from the cache, so
+ // that no dangling references are left behind. We could be a bit smarter if
+ // we kept a dependency graph. It's probably not worth the complexity.
+ for (PtrSetTy::iterator I=SeenVals.begin(), E=SeenVals.end(); I != E; ++I) {
+ CacheMapTy::iterator CacheIt = CacheMap.find(*I);
+ // non-computable results can be safely cached
+ if (CacheIt != CacheMap.end() && anyKnown(CacheIt->second))
+ CacheMap.erase(CacheIt);
+ }
+ }
+
+ SeenVals.clear();
+ return Result;
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
+ SizeOffsetType Const = Visitor.compute(V);
+ if (Visitor.bothKnown(Const))
+ return std::make_pair(ConstantInt::get(Context, Const.first),
+ ConstantInt::get(Context, Const.second));
+
+ V = V->stripPointerCasts();
+
+ // check cache
+ CacheMapTy::iterator CacheIt = CacheMap.find(V);
+ if (CacheIt != CacheMap.end())
+ return CacheIt->second;
+
+ // always generate code immediately before the instruction being
+ // processed, so that the generated code dominates the same BBs
+ Instruction *PrevInsertPoint = Builder.GetInsertPoint();
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ Builder.SetInsertPoint(I);
+
+ // record the pointers that were handled in this run, so that they can be
+ // cleaned later if something fails
+ SeenVals.insert(V);
+
+ // now compute the size and offset
+ SizeOffsetEvalType Result;
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+ Result = visitGEPOperator(*GEP);
+ } else if (Instruction *I = dyn_cast<Instruction>(V)) {
+ Result = visit(*I);
+ } else if (isa<Argument>(V) ||
+ (isa<ConstantExpr>(V) &&
+ cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
+ isa<GlobalVariable>(V)) {
+ // ignore values where we cannot do more than what ObjectSizeVisitor can
+ Result = unknown();
+ } else {
+ DEBUG(dbgs() << "ObjectSizeOffsetEvaluator::compute() unhandled value: "
+ << *V << '\n');
+ Result = unknown();
+ }
+
+ if (PrevInsertPoint)
+ Builder.SetInsertPoint(PrevInsertPoint);
+
+ // Don't reuse CacheIt since it may be invalid at this point.
+ CacheMap[V] = Result;
+ return Result;
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitAllocaInst(AllocaInst &I) {
+ if (!I.getAllocatedType()->isSized())
+ return unknown();
+
+ // must be a VLA
+ assert(I.isArrayAllocation());
+ Value *ArraySize = I.getArraySize();
+ Value *Size = ConstantInt::get(ArraySize->getType(),
+ TD->getTypeAllocSize(I.getAllocatedType()));
+ Size = Builder.CreateMul(Size, ArraySize);
+ return std::make_pair(Size, Zero);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
+ const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc);
+ if (!FnData)
+ return unknown();
+
+ // handle strdup-like functions separately
+ if (FnData->AllocTy == StrDupLike) {
+ // TODO
+ return unknown();
+ }
+
+ Value *FirstArg = CS.getArgument(FnData->FstParam);
+ if (FnData->SndParam == (unsigned char)-1)
+ return std::make_pair(FirstArg, Zero);
+
+ Value *SecondArg = CS.getArgument(FnData->SndParam);
+ Value *Size = Builder.CreateMul(FirstArg, SecondArg);
+ return std::make_pair(Size, Zero);
+
+ // TODO: handle more standard functions (+ wchar cousins):
+ // - strdup / strndup
+ // - strcpy / strncpy
+ // - strcat / strncat
+ // - memcpy / memmove
+ // - strcat / strncat
+ // - memset
+}
+
+SizeOffsetEvalType
+ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
+ SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
+ if (!bothKnown(PtrData))
+ return unknown();
+
+ Value *Offset = EmitGEPOffset(&Builder, *TD, &GEP);
+ Offset = Builder.CreateAdd(PtrData.second, Offset);
+ return std::make_pair(PtrData.first, Offset);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitIntToPtrInst(IntToPtrInst&) {
+ // clueless
+ return unknown();
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitLoadInst(LoadInst&) {
+ return unknown();
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitPHINode(PHINode &PHI) {
+ // create 2 PHIs: one for size and another for offset
+ PHINode *SizePHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
+ PHINode *OffsetPHI = Builder.CreatePHI(IntTy, PHI.getNumIncomingValues());
+
+ // insert right away in the cache to handle recursive PHIs
+ CacheMap[&PHI] = std::make_pair(SizePHI, OffsetPHI);
+
+ // compute offset/size for each PHI incoming pointer
+ for (unsigned i = 0, e = PHI.getNumIncomingValues(); i != e; ++i) {
+ Builder.SetInsertPoint(PHI.getIncomingBlock(i)->getFirstInsertionPt());
+ SizeOffsetEvalType EdgeData = compute_(PHI.getIncomingValue(i));
+
+ if (!bothKnown(EdgeData)) {
+ OffsetPHI->replaceAllUsesWith(UndefValue::get(IntTy));
+ OffsetPHI->eraseFromParent();
+ SizePHI->replaceAllUsesWith(UndefValue::get(IntTy));
+ SizePHI->eraseFromParent();
+ return unknown();
+ }
+ SizePHI->addIncoming(EdgeData.first, PHI.getIncomingBlock(i));
+ OffsetPHI->addIncoming(EdgeData.second, PHI.getIncomingBlock(i));
+ }
+ return std::make_pair(SizePHI, OffsetPHI);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
+ SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
+ SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());
+
+ if (!bothKnown(TrueSide) || !bothKnown(FalseSide))
+ return unknown();
+ if (TrueSide == FalseSide)
+ return TrueSide;
+
+ Value *Size = Builder.CreateSelect(I.getCondition(), TrueSide.first,
+ FalseSide.first);
+ Value *Offset = Builder.CreateSelect(I.getCondition(), TrueSide.second,
+ FalseSide.second);
+ return std::make_pair(Size, Offset);
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitInstruction(Instruction &I) {
+ DEBUG(dbgs() << "ObjectSizeOffsetEvaluator unknown instruction:" << I <<'\n');
+ return unknown();
+}