X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FValue.cpp;h=2fa5f08a3e7f05b3b99f74fb1ab3f5a60531c9fa;hb=23946fcaaefaf3c1a9d1ef86a3786f622c005f1a;hp=487196cffce030e89690dfe532938414fbaabadc;hpb=17aa92c92a925b4a674440c7ef088c223990e854;p=oota-llvm.git diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp index 487196cffce..2fa5f08a3e7 100644 --- a/lib/VMCore/Value.cpp +++ b/lib/VMCore/Value.cpp @@ -22,6 +22,7 @@ #include "llvm/ValueSymbolTable.h" #include "llvm/ADT/SmallString.h" #include "llvm/Support/Debug.h" +#include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/LeakDetector.h" #include "llvm/Support/ManagedStatic.h" @@ -34,22 +35,21 @@ using namespace llvm; // Value Class //===----------------------------------------------------------------------===// -static inline const Type *checkType(const Type *Ty) { +static inline Type *checkType(Type *Ty) { assert(Ty && "Value defined with a null type: Error!"); - return Ty; + return const_cast(Ty); } -Value::Value(const Type *ty, unsigned scid) +Value::Value(Type *ty, unsigned scid) : SubclassID(scid), HasValueHandle(0), - SubclassOptionalData(0), SubclassData(0), VTy(checkType(ty)), + SubclassOptionalData(0), SubclassData(0), VTy((Type*)checkType(ty)), UseList(0), Name(0) { + // FIXME: Why isn't this in the subclass gunk?? if (isa(this) || isa(this)) - assert((VTy->isFirstClassType() || VTy->isVoidTy() || - ty->isOpaqueTy() || VTy->isStructTy()) && - "invalid CallInst type!"); + assert((VTy->isFirstClassType() || VTy->isVoidTy() || VTy->isStructTy()) && + "invalid CallInst type!"); else if (!isa(this) && !isa(this)) - assert((VTy->isFirstClassType() || VTy->isVoidTy() || - ty->isOpaqueTy()) && + assert((VTy->isFirstClassType() || VTy->isVoidTy()) && "Cannot create non-first-class values except for constants!"); } @@ -254,7 +254,7 @@ void Value::takeName(Value *V) { // Get V's ST, this should always succed, because V has a name. ValueSymbolTable *VST; bool Failure = getSymTab(V, VST); - assert(!Failure && "V has a name, so it should have a ST!"); Failure=Failure; + assert(!Failure && "V has a name, so it should have a ST!"); (void)Failure; // If these values are both in the same symtab, we can do this very fast. // This works even if both values have no symtab yet. @@ -280,17 +280,16 @@ void Value::takeName(Value *V) { } -// uncheckedReplaceAllUsesWith - This is exactly the same as replaceAllUsesWith, -// except that it doesn't have all of the asserts. The asserts fail because we -// are half-way done resolving types, which causes some types to exist as two -// different Type*'s at the same time. This is a sledgehammer to work around -// this problem. -// -void Value::uncheckedReplaceAllUsesWith(Value *New) { +void Value::replaceAllUsesWith(Value *New) { + assert(New && "Value::replaceAllUsesWith() is invalid!"); + assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!"); + assert(New->getType() == getType() && + "replaceAllUses of value with new value of different type!"); + // Notify all ValueHandles (if present) that this value is going away. if (HasValueHandle) ValueHandleBase::ValueIsRAUWd(this, New); - + while (!use_empty()) { Use &U = *UseList; // Must handle Constants specially, we cannot call replaceUsesOfWith on a @@ -301,18 +300,12 @@ void Value::uncheckedReplaceAllUsesWith(Value *New) { continue; } } - + U.set(New); } -} - -void Value::replaceAllUsesWith(Value *New) { - assert(New && "Value::replaceAllUsesWith() is invalid!"); - assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!"); - assert(New->getType() == getType() && - "replaceAllUses of value with new value of different type!"); - - uncheckedReplaceAllUsesWith(New); + + if (BasicBlock *BB = dyn_cast(this)) + BB->replaceSuccessorsPhiUsesWith(cast(New)); } Value *Value::stripPointerCasts() { @@ -345,25 +338,62 @@ Value *Value::stripPointerCasts() { return V; } -Value *Value::getUnderlyingObject(unsigned MaxLookup) { - if (!getType()->isPointerTy()) - return this; - Value *V = this; - for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) { - if (GEPOperator *GEP = dyn_cast(V)) { - V = GEP->getPointerOperand(); - } else if (Operator::getOpcode(V) == Instruction::BitCast) { - V = cast(V)->getOperand(0); - } else if (GlobalAlias *GA = dyn_cast(V)) { - if (GA->mayBeOverridden()) - return V; - V = GA->getAliasee(); - } else { - return V; +/// isDereferenceablePointer - Test if this value is always a pointer to +/// allocated and suitably aligned memory for a simple load or store. +bool Value::isDereferenceablePointer() const { + // Note that it is not safe to speculate into a malloc'd region because + // malloc may return null. + // It's also not always safe to follow a bitcast, for example: + // bitcast i8* (alloca i8) to i32* + // would result in a 4-byte load from a 1-byte alloca. Some cases could + // be handled using TargetData to check sizes and alignments though. + + // These are obviously ok. + if (isa(this)) return true; + + // Global variables which can't collapse to null are ok. + if (const GlobalVariable *GV = dyn_cast(this)) + return !GV->hasExternalWeakLinkage(); + + // byval arguments are ok. + if (const Argument *A = dyn_cast(this)) + return A->hasByValAttr(); + + // For GEPs, determine if the indexing lands within the allocated object. + if (const GEPOperator *GEP = dyn_cast(this)) { + // Conservatively require that the base pointer be fully dereferenceable. + if (!GEP->getOperand(0)->isDereferenceablePointer()) + return false; + // Check the indices. + gep_type_iterator GTI = gep_type_begin(GEP); + for (User::const_op_iterator I = GEP->op_begin()+1, + E = GEP->op_end(); I != E; ++I) { + Value *Index = *I; + Type *Ty = *GTI++; + // Struct indices can't be out of bounds. + if (isa(Ty)) + continue; + ConstantInt *CI = dyn_cast(Index); + if (!CI) + return false; + // Zero is always ok. + if (CI->isZero()) + continue; + // Check to see that it's within the bounds of an array. + ArrayType *ATy = dyn_cast(Ty); + if (!ATy) + return false; + if (CI->getValue().getActiveBits() > 64) + return false; + if (CI->getZExtValue() >= ATy->getNumElements()) + return false; } - assert(V->getType()->isPointerTy() && "Unexpected operand type!"); + // Indices check out; this is dereferenceable. + return true; } - return V; + + // If we don't know, assume the worst. + return false; } /// DoPHITranslation - If this value is a PHI node with CurBB as its parent, @@ -488,10 +518,15 @@ void ValueHandleBase::ValueIsDeleted(Value *V) { ValueHandleBase *Entry = pImpl->ValueHandles[V]; assert(Entry && "Value bit set but no entries exist"); - // We use a local ValueHandleBase as an iterator so that - // ValueHandles can add and remove themselves from the list without - // breaking our iteration. This is not really an AssertingVH; we - // just have to give ValueHandleBase some kind. + // We use a local ValueHandleBase as an iterator so that ValueHandles can add + // and remove themselves from the list without breaking our iteration. This + // is not really an AssertingVH; we just have to give ValueHandleBase a kind. + // Note that we deliberately do not the support the case when dropping a value + // handle results in a new value handle being permanently added to the list + // (as might occur in theory for CallbackVH's): the new value handle will not + // be processed and the checking code will mete out righteous punishment if + // the handle is still present once we have finished processing all the other + // value handles (it is fine to momentarily add then remove a value handle). for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) { Iterator.RemoveFromUseList(); Iterator.AddToExistingUseListAfter(Entry); @@ -572,31 +607,26 @@ void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) { break; } } + +#ifndef NDEBUG + // If any new tracking or weak value handles were added while processing the + // list, then complain about it now. + if (Old->HasValueHandle) + for (Entry = pImpl->ValueHandles[Old]; Entry; Entry = Entry->Next) + switch (Entry->getKind()) { + case Tracking: + case Weak: + dbgs() << "After RAUW from " << *Old->getType() << " %" + << Old->getNameStr() << " to " << *New->getType() << " %" + << New->getNameStr() << "\n"; + llvm_unreachable("A tracking or weak value handle still pointed to the" + " old value!\n"); + default: + break; + } +#endif } /// ~CallbackVH. Empty, but defined here to avoid emitting the vtable /// more than once. CallbackVH::~CallbackVH() {} - - -//===----------------------------------------------------------------------===// -// User Class -//===----------------------------------------------------------------------===// - -// replaceUsesOfWith - Replaces all references to the "From" definition with -// references to the "To" definition. -// -void User::replaceUsesOfWith(Value *From, Value *To) { - if (From == To) return; // Duh what? - - assert((!isa(this) || isa(this)) && - "Cannot call User::replaceUsesOfWith on a constant!"); - - for (unsigned i = 0, E = getNumOperands(); i != E; ++i) - if (getOperand(i) == From) { // Is This operand is pointing to oldval? - // The side effects of this setOperand call include linking to - // "To", adding "this" to the uses list of To, and - // most importantly, removing "this" from the use list of "From". - setOperand(i, To); // Fix it now... - } -}