//===----------------------------------------------------------------------===//
//
// This family of functions identifies calls to builtin functions that allocate
-// or free memory.
+// or free memory.
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "memory-builtins"
#include "llvm/Analysis/MemoryBuiltins.h"
-#include "llvm/Constants.h"
-#include "llvm/Instructions.h"
-#include "llvm/Module.h"
-#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
-//===----------------------------------------------------------------------===//
-// malloc Call Utility Functions.
-//
+enum AllocType {
+ OpNewLike = 1<<0, // allocates; never returns null
+ MallocLike = 1<<1 | OpNewLike, // allocates; may return null
+ CallocLike = 1<<2, // allocates + bzero
+ ReallocLike = 1<<3, // reallocates
+ StrDupLike = 1<<4,
+ AllocLike = MallocLike | CallocLike | StrDupLike,
+ AnyAlloc = AllocLike | ReallocLike
+};
+
+struct AllocFnsTy {
+ LibFunc::Func Func;
+ AllocType AllocTy;
+ unsigned char NumParams;
+ // First and Second size parameters (or -1 if unused)
+ signed char FstParam, SndParam;
+};
+
+// FIXME: certain users need more information. E.g., SimplifyLibCalls needs to
+// know which functions are nounwind, noalias, nocapture parameters, etc.
+static const AllocFnsTy AllocationFnData[] = {
+ {LibFunc::malloc, MallocLike, 1, 0, -1},
+ {LibFunc::valloc, MallocLike, 1, 0, -1},
+ {LibFunc::Znwj, OpNewLike, 1, 0, -1}, // new(unsigned int)
+ {LibFunc::ZnwjRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new(unsigned int, nothrow)
+ {LibFunc::Znwm, OpNewLike, 1, 0, -1}, // new(unsigned long)
+ {LibFunc::ZnwmRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new(unsigned long, nothrow)
+ {LibFunc::Znaj, OpNewLike, 1, 0, -1}, // new[](unsigned int)
+ {LibFunc::ZnajRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new[](unsigned int, nothrow)
+ {LibFunc::Znam, OpNewLike, 1, 0, -1}, // new[](unsigned long)
+ {LibFunc::ZnamRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new[](unsigned long, nothrow)
+ {LibFunc::calloc, CallocLike, 2, 0, 1},
+ {LibFunc::realloc, ReallocLike, 2, 1, -1},
+ {LibFunc::reallocf, ReallocLike, 2, 1, -1},
+ {LibFunc::strdup, StrDupLike, 1, -1, -1},
+ {LibFunc::strndup, StrDupLike, 2, 1, -1}
+ // TODO: Handle "int posix_memalign(void **, size_t, size_t)"
+};
+
+
+static Function *getCalledFunction(const Value *V, bool LookThroughBitCast) {
+ if (LookThroughBitCast)
+ V = V->stripPointerCasts();
+
+ CallSite CS(const_cast<Value*>(V));
+ if (!CS.getInstruction())
+ return 0;
+
+ if (CS.isNoBuiltin())
+ return 0;
+
+ Function *Callee = CS.getCalledFunction();
+ if (!Callee || !Callee->isDeclaration())
+ return 0;
+ return Callee;
+}
-/// isMalloc - Returns true if the 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);
+/// \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,
+ const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast = false) {
+ // Skip intrinsics
+ if (isa<IntrinsicInst>(V))
+ return 0;
+
+ Function *Callee = getCalledFunction(V, LookThroughBitCast);
+ if (!Callee)
+ return 0;
+
+ // Make sure that the function is available.
+ StringRef FnName = Callee->getName();
+ LibFunc::Func TLIFn;
+ if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
+ return 0;
+
+ unsigned i = 0;
+ bool found = false;
+ for ( ; i < array_lengthof(AllocationFnData); ++i) {
+ if (AllocationFnData[i].Func == TLIFn) {
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ return 0;
+
+ const AllocFnsTy *FnData = &AllocationFnData[i];
+ if ((FnData->AllocTy & AllocTy) != FnData->AllocTy)
+ return 0;
+
+ // Check function prototype.
+ int FstParam = FnData->FstParam;
+ int SndParam = FnData->SndParam;
+ FunctionType *FTy = Callee->getFunctionType();
+
+ if (FTy->getReturnType() == Type::getInt8PtrTy(FTy->getContext()) &&
+ FTy->getNumParams() == FnData->NumParams &&
+ (FstParam < 0 ||
+ (FTy->getParamType(FstParam)->isIntegerTy(32) ||
+ FTy->getParamType(FstParam)->isIntegerTy(64))) &&
+ (SndParam < 0 ||
+ FTy->getParamType(SndParam)->isIntegerTy(32) ||
+ FTy->getParamType(SndParam)->isIntegerTy(64)))
+ return FnData;
+ return 0;
}
-static bool isMallocCall(const CallInst *CI) {
- if (!CI)
- return false;
+static bool hasNoAliasAttr(const Value *V, bool LookThroughBitCast) {
+ ImmutableCallSite CS(LookThroughBitCast ? V->stripPointerCasts() : V);
+ return CS && CS.hasFnAttr(Attribute::NoAlias);
+}
- const Module* M = CI->getParent()->getParent()->getParent();
- Function *MallocFunc = M->getFunction("malloc");
- if (CI->getOperand(0) != MallocFunc)
- return false;
+/// \brief Tests if a value is a call or invoke to a library function that
+/// allocates or reallocates memory (either malloc, calloc, realloc, or strdup
+/// like).
+bool llvm::isAllocationFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ return getAllocationData(V, AnyAlloc, TLI, LookThroughBitCast);
+}
- // Check malloc prototype.
- // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
- // attribute will exist.
- const FunctionType *FTy = MallocFunc->getFunctionType();
- if (FTy->getNumParams() != 1)
- return false;
- if (IntegerType *ITy = dyn_cast<IntegerType>(FTy->param_begin()->get())) {
- if (ITy->getBitWidth() != 32 && ITy->getBitWidth() != 64)
- return false;
- return true;
- }
+/// \brief Tests if a value is a call or invoke to a function that returns a
+/// NoAlias pointer (including malloc/calloc/realloc/strdup-like functions).
+bool llvm::isNoAliasFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ // it's safe to consider realloc as noalias since accessing the original
+ // pointer is undefined behavior
+ return isAllocationFn(V, TLI, LookThroughBitCast) ||
+ hasNoAliasAttr(V, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call or invoke to a library function that
+/// allocates uninitialized memory (such as malloc).
+bool llvm::isMallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ return getAllocationData(V, MallocLike, TLI, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call or invoke to a library function that
+/// allocates zero-filled memory (such as calloc).
+bool llvm::isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ return getAllocationData(V, CallocLike, TLI, LookThroughBitCast);
+}
- return false;
+/// \brief Tests if a value is a call or invoke to a library function that
+/// allocates memory (either malloc, calloc, or strdup like).
+bool llvm::isAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ return getAllocationData(V, AllocLike, TLI, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call or invoke to a library function that
+/// reallocates memory (such as realloc).
+bool llvm::isReallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ return getAllocationData(V, ReallocLike, TLI, LookThroughBitCast);
+}
+
+/// \brief Tests if a value is a call or invoke to a library function that
+/// allocates memory and never returns null (such as operator new).
+bool llvm::isOperatorNewLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+ bool LookThroughBitCast) {
+ return getAllocationData(V, OpNewLike, TLI, 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;
+const CallInst *llvm::extractMallocCall(const Value *I,
+ const TargetLibraryInfo *TLI) {
+ return isMallocLikeFn(I, TLI) ? dyn_cast<CallInst>(I) : 0;
}
-CallInst* llvm::extractMallocCall(Value* I) {
- CallInst *CI = dyn_cast<CallInst>(I);
- return (isMallocCall(CI)) ? CI : NULL;
+static Value *computeArraySize(const CallInst *CI, const DataLayout *DL,
+ const TargetLibraryInfo *TLI,
+ bool LookThroughSExt = false) {
+ if (!CI)
+ return 0;
+
+ // The size of the malloc's result type must be known to determine array size.
+ Type *T = getMallocAllocatedType(CI, TLI);
+ if (!T || !T->isSized() || !DL)
+ return 0;
+
+ unsigned ElementSize = DL->getTypeAllocSize(T);
+ if (StructType *ST = dyn_cast<StructType>(T))
+ ElementSize = DL->getStructLayout(ST)->getSizeInBytes();
+
+ // If malloc call's arg can be determined to be a multiple of ElementSize,
+ // return the multiple. Otherwise, return NULL.
+ Value *MallocArg = CI->getArgOperand(0);
+ Value *Multiple = 0;
+ if (ComputeMultiple(MallocArg, ElementSize, Multiple,
+ LookThroughSExt))
+ return Multiple;
+
+ return 0;
}
-static bool isBitCastOfMallocCall(const BitCastInst* BCI) {
- if (!BCI)
- return false;
-
- return isMallocCall(dyn_cast<CallInst>(BCI->getOperand(0)));
+/// isArrayMalloc - Returns the corresponding CallInst if the instruction
+/// is a call to malloc whose array size can be determined and the array size
+/// is not constant 1. Otherwise, return NULL.
+const CallInst *llvm::isArrayMalloc(const Value *I,
+ const DataLayout *DL,
+ const TargetLibraryInfo *TLI) {
+ const CallInst *CI = extractMallocCall(I, TLI);
+ Value *ArraySize = computeArraySize(CI, DL, TLI);
+
+ if (ConstantInt *ConstSize = dyn_cast_or_null<ConstantInt>(ArraySize))
+ if (ConstSize->isOne())
+ return CI;
+
+ // CI is a non-array malloc or we can't figure out that it is an array malloc.
+ return 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;
+/// getMallocType - Returns the PointerType resulting from the malloc call.
+/// The PointerType depends on the number of bitcast uses of the malloc call:
+/// 0: PointerType is the calls' return type.
+/// 1: PointerType is the bitcast's result type.
+/// >1: Unique PointerType cannot be determined, return NULL.
+PointerType *llvm::getMallocType(const CallInst *CI,
+ const TargetLibraryInfo *TLI) {
+ assert(isMallocLikeFn(CI, TLI) && "getMallocType and not malloc call");
+
+ PointerType *MallocType = 0;
+ unsigned NumOfBitCastUses = 0;
+
+ // Determine if CallInst has a bitcast use.
+ for (Value::const_user_iterator UI = CI->user_begin(), E = CI->user_end();
+ UI != E;)
+ if (const BitCastInst *BCI = dyn_cast<BitCastInst>(*UI++)) {
+ MallocType = cast<PointerType>(BCI->getDestTy());
+ NumOfBitCastUses++;
+ }
+
+ // Malloc call has 1 bitcast use, so type is the bitcast's destination type.
+ if (NumOfBitCastUses == 1)
+ return MallocType;
+
+ // Malloc call was not bitcast, so type is the malloc function's return type.
+ if (NumOfBitCastUses == 0)
+ return cast<PointerType>(CI->getType());
+
+ // Type could not be determined.
+ return 0;
}
-const CallInst* llvm::extractMallocCallFromBitCast(const Value* I) {
- const BitCastInst *BCI = dyn_cast<BitCastInst>(I);
- return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
- : NULL;
+/// getMallocAllocatedType - Returns the Type allocated by malloc call.
+/// The Type depends on the number of bitcast uses of the malloc call:
+/// 0: PointerType is the malloc calls' return type.
+/// 1: PointerType is the bitcast's result type.
+/// >1: Unique PointerType cannot be determined, return NULL.
+Type *llvm::getMallocAllocatedType(const CallInst *CI,
+ const TargetLibraryInfo *TLI) {
+ PointerType *PT = getMallocType(CI, TLI);
+ return PT ? PT->getElementType() : 0;
}
-static bool isArrayMallocHelper(const CallInst *CI, LLVMContext &Context,
- const TargetData* TD) {
- if (!CI)
- return false;
+/// getMallocArraySize - Returns the array size of a malloc call. If the
+/// argument passed to malloc is a multiple of the size of the malloced type,
+/// then return that multiple. For non-array mallocs, the multiple is
+/// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
+/// determined.
+Value *llvm::getMallocArraySize(CallInst *CI, const DataLayout *DL,
+ const TargetLibraryInfo *TLI,
+ bool LookThroughSExt) {
+ assert(isMallocLikeFn(CI, TLI) && "getMallocArraySize and not malloc call");
+ return computeArraySize(CI, DL, TLI, LookThroughSExt);
+}
+
+
+/// extractCallocCall - Returns the corresponding CallInst if the instruction
+/// is a calloc call.
+const CallInst *llvm::extractCallocCall(const Value *I,
+ const TargetLibraryInfo *TLI) {
+ return isCallocLikeFn(I, TLI) ? cast<CallInst>(I) : 0;
+}
+
+
+/// isFreeCall - Returns non-null if the value is a call to the builtin free()
+const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
+ const CallInst *CI = dyn_cast<CallInst>(I);
+ if (!CI || isa<IntrinsicInst>(CI))
+ return 0;
+ Function *Callee = CI->getCalledFunction();
+ if (Callee == 0 || !Callee->isDeclaration())
+ return 0;
+
+ StringRef FnName = Callee->getName();
+ LibFunc::Func TLIFn;
+ if (!TLI || !TLI->getLibFunc(FnName, TLIFn) || !TLI->has(TLIFn))
+ return 0;
+
+ unsigned ExpectedNumParams;
+ if (TLIFn == LibFunc::free ||
+ TLIFn == LibFunc::ZdlPv || // operator delete(void*)
+ TLIFn == LibFunc::ZdaPv) // operator delete[](void*)
+ ExpectedNumParams = 1;
+ else if (TLIFn == LibFunc::ZdlPvRKSt9nothrow_t || // delete(void*, nothrow)
+ TLIFn == LibFunc::ZdaPvRKSt9nothrow_t) // delete[](void*, nothrow)
+ ExpectedNumParams = 2;
+ else
+ return 0;
- const Type* T = getMallocAllocatedType(CI);
+ // Check free prototype.
+ // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
+ // attribute will exist.
+ FunctionType *FTy = Callee->getFunctionType();
+ if (!FTy->getReturnType()->isVoidTy())
+ return 0;
+ if (FTy->getNumParams() != ExpectedNumParams)
+ return 0;
+ if (FTy->getParamType(0) != Type::getInt8PtrTy(Callee->getContext()))
+ return 0;
+
+ return CI;
+}
- // We can only indentify an array malloc if we know the type of the malloc
- // call.
- if (!T) return false;
- Value* MallocArg = CI->getOperand(1);
- Constant *ElementSize = ConstantExpr::getSizeOf(T);
- ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
- MallocArg->getType());
- Constant *FoldedElementSize = ConstantFoldConstantExpression(
- cast<ConstantExpr>(ElementSize),
- Context, TD);
+//===----------------------------------------------------------------------===//
+// Utility functions to compute size of objects.
+//
- if (isa<ConstantExpr>(MallocArg))
- return (MallocArg != ElementSize);
- BinaryOperator *BI = dyn_cast<BinaryOperator>(MallocArg);
- if (!BI)
+/// \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 DataLayout *DL,
+ const TargetLibraryInfo *TLI, bool RoundToAlign) {
+ if (!DL)
return false;
- if (BI->getOpcode() == Instruction::Mul)
- // ArraySize * ElementSize
- if (BI->getOperand(1) == ElementSize ||
- (FoldedElementSize && BI->getOperand(1) == FoldedElementSize))
- return true;
+ ObjectSizeOffsetVisitor Visitor(DL, TLI, 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;
+}
- // TODO: Detect case where MallocArg mul has been transformed to shl.
- return false;
+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;
}
-/// isArrayMalloc - Returns the corresponding CallInst if the instruction
-/// matches the malloc call IR generated by CallInst::CreateMalloc(). This
-/// means that it is a malloc call with one bitcast use AND the malloc call's
-/// size argument is:
-/// 1. a constant not equal to the size of the malloced type
-/// or
-/// 2. the result of a multiplication by the size of the malloced type
-/// Otherwise it returns NULL.
-/// The unique bitcast is needed to determine the type/size of the array
-/// allocation.
-CallInst* llvm::isArrayMalloc(Value* I, LLVMContext &Context,
- const TargetData* TD) {
- CallInst *CI = extractMallocCall(I);
- return (isArrayMallocHelper(CI, Context, TD)) ? CI : NULL;
+ObjectSizeOffsetVisitor::ObjectSizeOffsetVisitor(const DataLayout *DL,
+ const TargetLibraryInfo *TLI,
+ LLVMContext &Context,
+ bool RoundToAlign)
+: DL(DL), TLI(TLI), RoundToAlign(RoundToAlign) {
+ // Pointer size must be rechecked for each object visited since it could have
+ // a different address space.
}
-const CallInst* llvm::isArrayMalloc(const Value* I, LLVMContext &Context,
- const TargetData* TD) {
- const CallInst *CI = extractMallocCall(I);
- return (isArrayMallocHelper(CI, Context, TD)) ? CI : NULL;
+SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
+ IntTyBits = DL->getPointerTypeSizeInBits(V->getType());
+ Zero = APInt::getNullValue(IntTyBits);
+
+ V = V->stripPointerCasts();
+ if (Instruction *I = dyn_cast<Instruction>(V)) {
+ // If we have already seen this instruction, bail out. Cycles can happen in
+ // unreachable code after constant propagation.
+ if (!SeenInsts.insert(I))
+ return unknown();
+
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
+ return visitGEPOperator(*GEP);
+ return visit(*I);
+ }
+ if (Argument *A = dyn_cast<Argument>(V))
+ return visitArgument(*A);
+ if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
+ return visitConstantPointerNull(*P);
+ if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
+ return visitGlobalAlias(*GA);
+ 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
+ if (CE->getOpcode() == Instruction::GetElementPtr)
+ return visitGEPOperator(cast<GEPOperator>(*CE));
+ }
+
+ DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: " << *V
+ << '\n');
+ return unknown();
}
-/// getMallocType - Returns the PointerType resulting from the malloc call.
-/// This PointerType is the result type of the call's only bitcast use.
-/// If there is no unique bitcast use, then return NULL.
-const PointerType* llvm::getMallocType(const CallInst* CI) {
- assert(isMalloc(CI) && "GetMallocType and not malloc call");
-
- const BitCastInst* BCI = NULL;
-
- // Determine if CallInst has a bitcast use.
- for (Value::use_const_iterator UI = CI->use_begin(), E = CI->use_end();
- UI != E; )
- if ((BCI = dyn_cast<BitCastInst>(cast<Instruction>(*UI++))))
- break;
+SizeOffsetType ObjectSizeOffsetVisitor::visitAllocaInst(AllocaInst &I) {
+ if (!I.getAllocatedType()->isSized())
+ return unknown();
- // Malloc call has 1 bitcast use and no other uses, so type is the bitcast's
- // destination type.
- if (BCI && CI->hasOneUse())
- return cast<PointerType>(BCI->getDestTy());
+ APInt Size(IntTyBits, DL->getTypeAllocSize(I.getAllocatedType()));
+ if (!I.isArrayAllocation())
+ return std::make_pair(align(Size, I.getAlignment()), Zero);
- // Malloc call was not bitcast, so type is the malloc function's return type.
- if (!BCI)
- return cast<PointerType>(CI->getType());
+ 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();
+}
- // Type could not be determined.
- return NULL;
-}
-
-/// getMallocAllocatedType - Returns the Type allocated by malloc call. This
-/// Type is the result type of the call's only bitcast use. If there is no
-/// unique bitcast use, then return NULL.
-const Type* llvm::getMallocAllocatedType(const CallInst* CI) {
- const PointerType* PT = getMallocType(CI);
- return PT ? PT->getElementType() : NULL;
-}
-
-/// isSafeToGetMallocArraySize - Returns true if the array size of a malloc can
-/// be determined. It can be determined in these 3 cases of malloc codegen:
-/// 1. non-array malloc: The malloc's size argument is a constant and equals the /// size of the type being malloced.
-/// 2. array malloc: This is a malloc call with one bitcast use AND the malloc
-/// call's size argument is a constant multiple of the size of the malloced
-/// type.
-/// 3. array malloc: This is a malloc call with one bitcast use AND the malloc
-/// call's size argument is the result of a multiplication by the size of the
-/// malloced type.
-/// Otherwise returns false.
-static bool isSafeToGetMallocArraySize(const CallInst *CI,
- LLVMContext &Context,
- const TargetData* TD) {
- if (!CI)
- return false;
+SizeOffsetType ObjectSizeOffsetVisitor::visitArgument(Argument &A) {
+ // no interprocedural analysis is done at the moment
+ if (!A.hasByValOrInAllocaAttr()) {
+ ++ObjectVisitorArgument;
+ return unknown();
+ }
+ PointerType *PT = cast<PointerType>(A.getType());
+ APInt Size(IntTyBits, DL->getTypeAllocSize(PT->getElementType()));
+ return std::make_pair(align(Size, A.getParamAlignment()), Zero);
+}
- // Type must be known to determine array size.
- const Type* T = getMallocAllocatedType(CI);
- if (!T) return false;
+SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
+ const AllocFnsTy *FnData = getAllocationData(CS.getInstruction(), AnyAlloc,
+ TLI);
+ if (!FnData)
+ return unknown();
+
+ // handle strdup-like functions separately
+ if (FnData->AllocTy == StrDupLike) {
+ APInt Size(IntTyBits, GetStringLength(CS.getArgument(0)));
+ if (!Size)
+ return unknown();
+
+ // strndup limits strlen
+ if (FnData->FstParam > 0) {
+ ConstantInt *Arg= dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
+ if (!Arg)
+ return unknown();
+
+ APInt MaxSize = Arg->getValue().zextOrSelf(IntTyBits);
+ if (Size.ugt(MaxSize))
+ Size = MaxSize + 1;
+ }
+ return std::make_pair(Size, Zero);
+ }
- Value* MallocArg = CI->getOperand(1);
- Constant *ElementSize = ConstantExpr::getSizeOf(T);
- ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
- MallocArg->getType());
+ ConstantInt *Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->FstParam));
+ if (!Arg)
+ return unknown();
+
+ APInt Size = Arg->getValue().zextOrSelf(IntTyBits);
+ // size determined by just 1 parameter
+ if (FnData->SndParam < 0)
+ return std::make_pair(Size, Zero);
+
+ Arg = dyn_cast<ConstantInt>(CS.getArgument(FnData->SndParam));
+ if (!Arg)
+ return unknown();
+
+ Size *= Arg->getValue().zextOrSelf(IntTyBits);
+ return std::make_pair(Size, Zero);
+
+ // TODO: handle more standard functions (+ wchar cousins):
+ // - strdup / strndup
+ // - strcpy / strncpy
+ // - strcat / strncat
+ // - memcpy / memmove
+ // - strcat / strncat
+ // - memset
+}
- // First, check if it is a non-array malloc.
- if (isa<ConstantExpr>(MallocArg) && (MallocArg == ElementSize))
- return true;
+SizeOffsetType
+ObjectSizeOffsetVisitor::visitConstantPointerNull(ConstantPointerNull&) {
+ return std::make_pair(Zero, Zero);
+}
- // Second, check if it can be determined that this is an array malloc.
- return isArrayMallocHelper(CI, Context, TD);
+SizeOffsetType
+ObjectSizeOffsetVisitor::visitExtractElementInst(ExtractElementInst&) {
+ return unknown();
}
-/// isConstantOne - Return true only if val is constant int 1.
-static bool isConstantOne(Value *val) {
- return isa<ConstantInt>(val) && cast<ConstantInt>(val)->isOne();
+SizeOffsetType
+ObjectSizeOffsetVisitor::visitExtractValueInst(ExtractValueInst&) {
+ // Easy cases were already folded by previous passes.
+ return unknown();
}
-/// getMallocArraySize - Returns the array size of a malloc call. For array
-/// mallocs, the size is computated in 1 of 3 ways:
-/// 1. If the element type is of size 1, then array size is the argument to
-/// malloc.
-/// 2. Else if the malloc's argument is a constant, the array size is that
-/// argument divided by the element type's size.
-/// 3. Else the malloc argument must be a multiplication and the array size is
-/// the first operand of the multiplication.
-/// For non-array mallocs, the computed size is constant 1.
-/// This function returns NULL for all mallocs whose array size cannot be
-/// determined.
-Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
- const TargetData* TD) {
- if (!isSafeToGetMallocArraySize(CI, Context, TD))
- return NULL;
-
- // Match CreateMalloc's use of constant 1 array-size for non-array mallocs.
- if (!isArrayMalloc(CI, Context, TD))
- return ConstantInt::get(CI->getOperand(1)->getType(), 1);
-
- Value* MallocArg = CI->getOperand(1);
- assert(getMallocAllocatedType(CI) && "getMallocArraySize and no type");
- Constant *ElementSize = ConstantExpr::getSizeOf(getMallocAllocatedType(CI));
- ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
- MallocArg->getType());
-
- Constant* CO = dyn_cast<Constant>(MallocArg);
- BinaryOperator* BO = dyn_cast<BinaryOperator>(MallocArg);
- assert((isConstantOne(ElementSize) || CO || BO) &&
- "getMallocArraySize and malformed malloc IR");
-
- if (isConstantOne(ElementSize))
- return MallocArg;
-
- if (CO)
- return CO->getOperand(0);
-
- // TODO: Detect case where MallocArg mul has been transformed to shl.
-
- assert(BO && "getMallocArraySize not constant but not multiplication either");
- return BO->getOperand(0);
+SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
+ SizeOffsetType PtrData = compute(GEP.getPointerOperand());
+ APInt Offset(IntTyBits, 0);
+ if (!bothKnown(PtrData) || !GEP.accumulateConstantOffset(*DL, Offset))
+ return unknown();
+
+ return std::make_pair(PtrData.first, PtrData.second + Offset);
}
-//===----------------------------------------------------------------------===//
-// free Call Utility Functions.
-//
+SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalAlias(GlobalAlias &GA) {
+ if (GA.mayBeOverridden())
+ return unknown();
+ return compute(GA.getAliasee());
+}
-/// isFreeCall - Returns true if the the value is a call to the builtin free()
-bool llvm::isFreeCall(const Value* I) {
- const CallInst *CI = dyn_cast<CallInst>(I);
- if (!CI)
- return false;
+SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
+ if (!GV.hasDefinitiveInitializer())
+ return unknown();
- const Module* M = CI->getParent()->getParent()->getParent();
- Function *FreeFunc = M->getFunction("free");
+ APInt Size(IntTyBits, DL->getTypeAllocSize(GV.getType()->getElementType()));
+ return std::make_pair(align(Size, GV.getAlignment()), Zero);
+}
- if (CI->getOperand(0) != FreeFunc)
- return false;
+SizeOffsetType ObjectSizeOffsetVisitor::visitIntToPtrInst(IntToPtrInst&) {
+ // clueless
+ return unknown();
+}
- // Check free prototype.
- // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
- // attribute will exist.
- const FunctionType *FTy = FreeFunc->getFunctionType();
- if (FTy->getReturnType() != Type::getVoidTy(M->getContext()))
- return false;
- if (FTy->getNumParams() != 1)
- return false;
- if (FTy->param_begin()->get() != Type::getInt8PtrTy(M->getContext()))
- return false;
+SizeOffsetType ObjectSizeOffsetVisitor::visitLoadInst(LoadInst&) {
+ ++ObjectVisitorLoad;
+ return unknown();
+}
- return true;
+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 DataLayout *DL,
+ const TargetLibraryInfo *TLI,
+ LLVMContext &Context,
+ bool RoundToAlign)
+: DL(DL), TLI(TLI), Context(Context), Builder(Context, TargetFolder(DL)),
+ RoundToAlign(RoundToAlign) {
+ // IntTy and Zero must be set for each compute() since the address space may
+ // be different for later objects.
+}
+
+SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
+ // XXX - Are vectors of pointers possible here?
+ IntTy = cast<IntegerType>(DL->getIntPtrType(V->getType()));
+ Zero = ConstantInt::get(IntTy, 0);
+
+ 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) {
+ ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, RoundToAlign);
+ 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);
+
+ // now compute the size and offset
+ SizeOffsetEvalType Result;
+
+ // Record the pointers that were handled in this run, so that they can be
+ // cleaned later if something fails. We also use this set to break cycles that
+ // can occur in dead code.
+ if (!SeenVals.insert(V)) {
+ Result = unknown();
+ } else 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<GlobalAlias>(V) ||
+ 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(),
+ DL->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,
+ TLI);
+ if (!FnData)
+ return unknown();
+
+ // handle strdup-like functions separately
+ if (FnData->AllocTy == StrDupLike) {
+ // TODO
+ return unknown();
+ }
+
+ Value *FirstArg = CS.getArgument(FnData->FstParam);
+ FirstArg = Builder.CreateZExt(FirstArg, IntTy);
+ if (FnData->SndParam < 0)
+ return std::make_pair(FirstArg, Zero);
+
+ Value *SecondArg = CS.getArgument(FnData->SndParam);
+ SecondArg = Builder.CreateZExt(SecondArg, IntTy);
+ 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::visitExtractElementInst(ExtractElementInst&) {
+ return unknown();
+}
+
+SizeOffsetEvalType
+ObjectSizeOffsetEvaluator::visitExtractValueInst(ExtractValueInst&) {
+ return unknown();
+}
+
+SizeOffsetEvalType
+ObjectSizeOffsetEvaluator::visitGEPOperator(GEPOperator &GEP) {
+ SizeOffsetEvalType PtrData = compute_(GEP.getPointerOperand());
+ if (!bothKnown(PtrData))
+ return unknown();
+
+ Value *Offset = EmitGEPOffset(&Builder, *DL, &GEP, /*NoAssumptions=*/true);
+ 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));
+ }
+
+ Value *Size = SizePHI, *Offset = OffsetPHI, *Tmp;
+ if ((Tmp = SizePHI->hasConstantValue())) {
+ Size = Tmp;
+ SizePHI->replaceAllUsesWith(Size);
+ SizePHI->eraseFromParent();
+ }
+ if ((Tmp = OffsetPHI->hasConstantValue())) {
+ Offset = Tmp;
+ OffsetPHI->replaceAllUsesWith(Offset);
+ OffsetPHI->eraseFromParent();
+ }
+ return std::make_pair(Size, Offset);
+}
+
+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();
}
projects / oota-llvm.git / blobdiff