X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FVMCore%2FValue.cpp;h=2bdb5b8a79ce2aad29d3be4b9dc5cf88414bfbbb;hb=3778f21b17e675c2fd1600901361fa4a73888eba;hp=dd06441a953df2685c19c9bb92ee5c539a3fdb04;hpb=04cb800c324ef661017aff474e266ed7f2cddb90;p=oota-llvm.git diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp index dd06441a953..2bdb5b8a79c 100644 --- a/lib/VMCore/Value.cpp +++ b/lib/VMCore/Value.cpp @@ -1,24 +1,36 @@ //===-- Value.cpp - Implement the Value class -----------------------------===// -// +// // The LLVM Compiler Infrastructure // -// This file was developed by the LLVM research group and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. -// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// //===----------------------------------------------------------------------===// // -// This file implements the Value and User classes. +// This file implements the Value, ValueHandle, and User classes. // //===----------------------------------------------------------------------===// #include "llvm/Constant.h" +#include "llvm/Constants.h" #include "llvm/DerivedTypes.h" #include "llvm/InstrTypes.h" +#include "llvm/Instructions.h" +#include "llvm/Operator.h" #include "llvm/Module.h" -#include "llvm/SymbolTable.h" +#include "llvm/Metadata.h" +#include "llvm/ValueSymbolTable.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" #include "llvm/Support/LeakDetector.h" +#include "llvm/Support/ManagedStatic.h" +#include "llvm/Support/ValueHandle.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/System/RWMutex.h" +#include "llvm/System/Threading.h" +#include "llvm/ADT/DenseMap.h" #include -#include using namespace llvm; //===----------------------------------------------------------------------===// @@ -30,34 +42,48 @@ static inline const Type *checkType(const Type *Ty) { return Ty; } -Value::Value(const Type *ty, unsigned scid, const std::string &name) - : SubclassID(scid), SubclassData(0), Ty(checkType(ty)), - UseList(0), Name(name) { - if (!isa(this) && !isa(this)) - assert((Ty->isFirstClassType() || Ty == Type::VoidTy || +Value::Value(const Type *ty, unsigned scid) + : SubclassID(scid), HasValueHandle(0), SubclassOptionalData(0), + SubclassData(0), VTy(checkType(ty)), + UseList(0), Name(0) { + if (isa(this) || isa(this)) + assert((VTy->isFirstClassType() || + VTy == Type::getVoidTy(ty->getContext()) || + isa(ty) || VTy->getTypeID() == Type::StructTyID) && + "invalid CallInst type!"); + else if (!isa(this) && !isa(this)) + assert((VTy->isFirstClassType() || + VTy == Type::getVoidTy(ty->getContext()) || isa(ty)) && "Cannot create non-first-class values except for constants!"); - if (ty == Type::VoidTy) - assert(name.empty() && "Cannot have named void values!"); } Value::~Value() { + // Notify all ValueHandles (if present) that this value is going away. + if (HasValueHandle) + ValueHandleBase::ValueIsDeleted(this); + #ifndef NDEBUG // Only in -g mode... // Check to make sure that there are no uses of this value that are still // around when the value is destroyed. If there are, then we have a dangling // reference and something is wrong. This code is here to print out what is - // still being referenced. The value in question should be printed as + // still being referenced. The value in question should be printed as // a // - if (use_begin() != use_end()) { - std::cerr << "While deleting: " << *Ty << " %" << Name << "\n"; + if (!use_empty()) { + errs() << "While deleting: " << *VTy << " %" << getNameStr() << "\n"; for (use_iterator I = use_begin(), E = use_end(); I != E; ++I) - std::cerr << "Use still stuck around after Def is destroyed:" - << **I << "\n"; + errs() << "Use still stuck around after Def is destroyed:" + << **I << "\n"; } #endif - assert(use_begin() == use_end() && "Uses remain when a value is destroyed!"); + assert(use_empty() && "Uses remain when a value is destroyed!"); + // If this value is named, destroy the name. This should not be in a symtab + // at this point. + if (Name) + Name->Destroy(); + // There should be no uses of this object anymore, remove it. LeakDetector::removeGarbageObject(this); } @@ -84,6 +110,17 @@ bool Value::hasNUsesOrMore(unsigned N) const { return true; } +/// isUsedInBasicBlock - Return true if this value is used in the specified +/// basic block. +bool Value::isUsedInBasicBlock(const BasicBlock *BB) const { + for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) { + const Instruction *User = dyn_cast(*I); + if (User && User->getParent() == BB) + return true; + } + return false; +} + /// getNumUses - This method computes the number of uses of this Value. This /// is a linear time operation. Use hasOneUse or hasNUses to check for specific @@ -92,42 +129,166 @@ unsigned Value::getNumUses() const { return (unsigned)std::distance(use_begin(), use_end()); } +static bool getSymTab(Value *V, ValueSymbolTable *&ST) { + ST = 0; + if (Instruction *I = dyn_cast(V)) { + if (BasicBlock *P = I->getParent()) + if (Function *PP = P->getParent()) + ST = &PP->getValueSymbolTable(); + } else if (BasicBlock *BB = dyn_cast(V)) { + if (Function *P = BB->getParent()) + ST = &P->getValueSymbolTable(); + } else if (GlobalValue *GV = dyn_cast(V)) { + if (Module *P = GV->getParent()) + ST = &P->getValueSymbolTable(); + } else if (Argument *A = dyn_cast(V)) { + if (Function *P = A->getParent()) + ST = &P->getValueSymbolTable(); + } else if (NamedMDNode *N = dyn_cast(V)) { + if (Module *P = N->getParent()) { + ST = &P->getValueSymbolTable(); + } + } else if (isa(V)) + return true; + else { + assert(isa(V) && "Unknown value type!"); + return true; // no name is setable for this. + } + return false; +} -void Value::setName(const std::string &name) { - if (Name == name) return; // Name is already set. +StringRef Value::getName() const { + // Make sure the empty string is still a C string. For historical reasons, + // some clients want to call .data() on the result and expect it to be null + // terminated. + if (!Name) return StringRef("", 0); + return Name->getKey(); +} + +std::string Value::getNameStr() const { + return getName().str(); +} + +void Value::setName(const Twine &NewName) { + SmallString<32> NameData; + NewName.toVector(NameData); + + const char *NameStr = NameData.data(); + unsigned NameLen = NameData.size(); + // Name isn't changing? + if (getName() == StringRef(NameStr, NameLen)) + return; + + assert(getType() != Type::getVoidTy(getContext()) && + "Cannot assign a name to void values!"); + // Get the symbol table to update for this object. - SymbolTable *ST = 0; - if (Instruction *I = dyn_cast(this)) { - if (BasicBlock *P = I->getParent()) - if (Function *PP = P->getParent()) - ST = &PP->getSymbolTable(); - } else if (BasicBlock *BB = dyn_cast(this)) { - if (Function *P = BB->getParent()) ST = &P->getSymbolTable(); - } else if (GlobalValue *GV = dyn_cast(this)) { - if (Module *P = GV->getParent()) ST = &P->getSymbolTable(); - } else if (Argument *A = dyn_cast(this)) { - if (Function *P = A->getParent()) ST = &P->getSymbolTable(); - } else { - assert(isa(this) && "Unknown value type!"); - return; // no name is setable for this. - } - - if (!ST) // No symbol table to update? Just do the change. - Name = name; - else if (hasName()) { - if (!name.empty()) { // Replacing name. - ST->changeName(this, name); - } else { // Transitioning from hasName -> noname. - ST->remove(this); - Name.clear(); + ValueSymbolTable *ST; + if (getSymTab(this, ST)) + return; // Cannot set a name on this value (e.g. constant). + + if (!ST) { // No symbol table to update? Just do the change. + if (NameLen == 0) { + // Free the name for this value. + Name->Destroy(); + Name = 0; + return; } - } else { // Transitioning from noname -> hasName. - Name = name; - ST->insert(this); + + if (Name) + Name->Destroy(); + + // NOTE: Could optimize for the case the name is shrinking to not deallocate + // then reallocated. + + // Create the new name. + Name = ValueName::Create(NameStr, NameStr+NameLen); + Name->setValue(this); + return; } + + // NOTE: Could optimize for the case the name is shrinking to not deallocate + // then reallocated. + if (hasName()) { + // Remove old name. + ST->removeValueName(Name); + Name->Destroy(); + Name = 0; + + if (NameLen == 0) + return; + } + + // Name is changing to something new. + Name = ST->createValueName(StringRef(NameStr, NameLen), this); +} + + +/// takeName - transfer the name from V to this value, setting V's name to +/// empty. It is an error to call V->takeName(V). +void Value::takeName(Value *V) { + ValueSymbolTable *ST = 0; + // If this value has a name, drop it. + if (hasName()) { + // Get the symtab this is in. + if (getSymTab(this, ST)) { + // We can't set a name on this value, but we need to clear V's name if + // it has one. + if (V->hasName()) V->setName(""); + return; // Cannot set a name on this value (e.g. constant). + } + + // Remove old name. + if (ST) + ST->removeValueName(Name); + Name->Destroy(); + Name = 0; + } + + // Now we know that this has no name. + + // If V has no name either, we're done. + if (!V->hasName()) return; + + // Get this's symtab if we didn't before. + if (!ST) { + if (getSymTab(this, ST)) { + // Clear V's name. + V->setName(""); + return; // Cannot set a name on this value (e.g. constant). + } + } + + // 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; + + // 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. + if (ST == VST) { + // Take the name! + Name = V->Name; + V->Name = 0; + Name->setValue(this); + return; + } + + // Otherwise, things are slightly more complex. Remove V's name from VST and + // then reinsert it into ST. + + if (VST) + VST->removeValueName(V->Name); + Name = V->Name; + V->Name = 0; + Name->setValue(this); + + if (ST) + ST->reinsertValue(this); } + // 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 @@ -135,18 +296,22 @@ void Value::setName(const std::string &name) { // this problem. // void Value::uncheckedReplaceAllUsesWith(Value *New) { + // 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 - // constant! + // constant because they are uniqued. if (Constant *C = dyn_cast(U.getUser())) { - if (!isa(C)) - C->replaceUsesOfWithOnConstant(this, New, true); - else - U.set(New); - } else { - U.set(New); + if (!isa(C)) { + C->replaceUsesOfWithOnConstant(this, New, &U); + continue; + } } + + U.set(New); } } @@ -159,6 +324,227 @@ void Value::replaceAllUsesWith(Value *New) { uncheckedReplaceAllUsesWith(New); } +Value *Value::stripPointerCasts() { + if (!isa(getType())) + return this; + Value *V = this; + do { + if (GEPOperator *GEP = dyn_cast(V)) { + if (!GEP->hasAllZeroIndices()) + return V; + V = GEP->getPointerOperand(); + } else if (Operator::getOpcode(V) == Instruction::BitCast) { + V = cast(V)->getOperand(0); + } else { + return V; + } + assert(isa(V->getType()) && "Unexpected operand type!"); + } while (1); +} + +Value *Value::getUnderlyingObject() { + if (!isa(getType())) + return this; + Value *V = this; + unsigned MaxLookup = 6; + do { + if (GEPOperator *GEP = dyn_cast(V)) { + V = GEP->getPointerOperand(); + } else if (Operator::getOpcode(V) == Instruction::BitCast) { + V = cast(V)->getOperand(0); + } else { + return V; + } + assert(isa(V->getType()) && "Unexpected operand type!"); + } while (--MaxLookup); + return V; +} + +/// DoPHITranslation - If this value is a PHI node with CurBB as its parent, +/// return the value in the PHI node corresponding to PredBB. If not, return +/// ourself. This is useful if you want to know the value something has in a +/// predecessor block. +Value *Value::DoPHITranslation(const BasicBlock *CurBB, + const BasicBlock *PredBB) { + PHINode *PN = dyn_cast(this); + if (PN && PN->getParent() == CurBB) + return PN->getIncomingValueForBlock(PredBB); + return this; +} + +LLVMContext &Value::getContext() const { return VTy->getContext(); } + +//===----------------------------------------------------------------------===// +// ValueHandleBase Class +//===----------------------------------------------------------------------===// + +/// ValueHandles - This map keeps track of all of the value handles that are +/// watching a Value*. The Value::HasValueHandle bit is used to know whether or +/// not a value has an entry in this map. +typedef DenseMap ValueHandlesTy; +static ManagedStatic ValueHandles; +static ManagedStatic > ValueHandlesLock; + +/// AddToExistingUseList - Add this ValueHandle to the use list for VP, where +/// List is known to point into the existing use list. +void ValueHandleBase::AddToExistingUseList(ValueHandleBase **List) { + assert(List && "Handle list is null?"); + + // Splice ourselves into the list. + Next = *List; + *List = this; + setPrevPtr(List); + if (Next) { + Next->setPrevPtr(&Next); + assert(VP == Next->VP && "Added to wrong list?"); + } +} + +/// AddToUseList - Add this ValueHandle to the use list for VP. +void ValueHandleBase::AddToUseList() { + assert(VP && "Null pointer doesn't have a use list!"); + if (VP->HasValueHandle) { + // If this value already has a ValueHandle, then it must be in the + // ValueHandles map already. + sys::SmartScopedReader Reader(*ValueHandlesLock); + ValueHandleBase *&Entry = (*ValueHandles)[VP]; + assert(Entry != 0 && "Value doesn't have any handles?"); + AddToExistingUseList(&Entry); + return; + } + + // Ok, it doesn't have any handles yet, so we must insert it into the + // DenseMap. However, doing this insertion could cause the DenseMap to + // reallocate itself, which would invalidate all of the PrevP pointers that + // point into the old table. Handle this by checking for reallocation and + // updating the stale pointers only if needed. + sys::SmartScopedWriter Writer(*ValueHandlesLock); + ValueHandlesTy &Handles = *ValueHandles; + const void *OldBucketPtr = Handles.getPointerIntoBucketsArray(); + + ValueHandleBase *&Entry = Handles[VP]; + assert(Entry == 0 && "Value really did already have handles?"); + AddToExistingUseList(&Entry); + VP->HasValueHandle = true; + + // If reallocation didn't happen or if this was the first insertion, don't + // walk the table. + if (Handles.isPointerIntoBucketsArray(OldBucketPtr) || + Handles.size() == 1) { + return; + } + + // Okay, reallocation did happen. Fix the Prev Pointers. + for (ValueHandlesTy::iterator I = Handles.begin(), E = Handles.end(); + I != E; ++I) { + assert(I->second && I->first == I->second->VP && "List invariant broken!"); + I->second->setPrevPtr(&I->second); + } +} + +/// RemoveFromUseList - Remove this ValueHandle from its current use list. +void ValueHandleBase::RemoveFromUseList() { + assert(VP && VP->HasValueHandle && "Pointer doesn't have a use list!"); + + // Unlink this from its use list. + ValueHandleBase **PrevPtr = getPrevPtr(); + assert(*PrevPtr == this && "List invariant broken"); + + *PrevPtr = Next; + if (Next) { + assert(Next->getPrevPtr() == &Next && "List invariant broken"); + Next->setPrevPtr(PrevPtr); + return; + } + + // If the Next pointer was null, then it is possible that this was the last + // ValueHandle watching VP. If so, delete its entry from the ValueHandles + // map. + sys::SmartScopedWriter Writer(*ValueHandlesLock); + ValueHandlesTy &Handles = *ValueHandles; + if (Handles.isPointerIntoBucketsArray(PrevPtr)) { + Handles.erase(VP); + VP->HasValueHandle = false; + } +} + + +void ValueHandleBase::ValueIsDeleted(Value *V) { + assert(V->HasValueHandle && "Should only be called if ValueHandles present"); + + // Get the linked list base, which is guaranteed to exist since the + // HasValueHandle flag is set. + ValueHandlesLock->reader_acquire(); + ValueHandleBase *Entry = (*ValueHandles)[V]; + ValueHandlesLock->reader_release(); + assert(Entry && "Value bit set but no entries exist"); + + while (Entry) { + // Advance pointer to avoid invalidation. + ValueHandleBase *ThisNode = Entry; + Entry = Entry->Next; + + switch (ThisNode->getKind()) { + case Assert: +#ifndef NDEBUG // Only in -g mode... + errs() << "While deleting: " << *V->getType() << " %" << V->getNameStr() + << "\n"; +#endif + llvm_unreachable("An asserting value handle still pointed to this" + " value!"); + case Weak: + // Weak just goes to null, which will unlink it from the list. + ThisNode->operator=(0); + break; + case Callback: + // Forward to the subclass's implementation. + static_cast(ThisNode)->deleted(); + break; + } + } + + // All callbacks and weak references should be dropped by now. + assert(!V->HasValueHandle && "All references to V were not removed?"); +} + + +void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) { + assert(Old->HasValueHandle &&"Should only be called if ValueHandles present"); + assert(Old != New && "Changing value into itself!"); + + // Get the linked list base, which is guaranteed to exist since the + // HasValueHandle flag is set. + ValueHandlesLock->reader_acquire(); + ValueHandleBase *Entry = (*ValueHandles)[Old]; + ValueHandlesLock->reader_release(); + assert(Entry && "Value bit set but no entries exist"); + + while (Entry) { + // Advance pointer to avoid invalidation. + ValueHandleBase *ThisNode = Entry; + Entry = Entry->Next; + + switch (ThisNode->getKind()) { + case Assert: + // Asserting handle does not follow RAUW implicitly. + break; + case Weak: + // Weak goes to the new value, which will unlink it from Old's list. + ThisNode->operator=(New); + break; + case Callback: + // Forward to the subclass's implementation. + static_cast(ThisNode)->allUsesReplacedWith(New); + break; + } + } +} + +/// ~CallbackVH. Empty, but defined here to avoid emitting the vtable +/// more than once. +CallbackVH::~CallbackVH() {} + + //===----------------------------------------------------------------------===// // User Class //===----------------------------------------------------------------------===// @@ -169,8 +555,8 @@ void Value::replaceAllUsesWith(Value *New) { 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!"); + 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? @@ -180,4 +566,3 @@ void User::replaceUsesOfWith(Value *From, Value *To) { setOperand(i, To); // Fix it now... } } -