//
//===----------------------------------------------------------------------===//
//
-// This file implements the Value and User classes.
+// This file implements the Value, ValueHandle, and User classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/ValueSymbolTable.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/LeakDetector.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/System/RWMutex.h"
+#include "llvm/System/Threading.h"
+#include "llvm/ADT/DenseMap.h"
#include <algorithm>
using namespace llvm;
}
Value::Value(const Type *ty, unsigned scid)
- : SubclassID(scid), SubclassData(0), Ty(checkType(ty)),
+ : SubclassID(scid), HasValueHandle(0), SubclassData(0), VTy(checkType(ty)),
UseList(0), Name(0) {
if (isa<CallInst>(this) || isa<InvokeInst>(this))
- assert((Ty->isFirstClassType() || Ty == Type::VoidTy ||
- isa<OpaqueType>(ty) || Ty->getTypeID() == Type::StructTyID) &&
+ assert((VTy->isFirstClassType() || VTy == Type::VoidTy ||
+ isa<OpaqueType>(ty) || VTy->getTypeID() == Type::StructTyID) &&
"invalid CallInst type!");
else if (!isa<Constant>(this) && !isa<BasicBlock>(this))
- assert((Ty->isFirstClassType() || Ty == Type::VoidTy ||
+ assert((VTy->isFirstClassType() || VTy == Type::VoidTy ||
isa<OpaqueType>(ty)) &&
"Cannot create non-first-class values except for constants!");
}
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
// a <badref>
//
if (!use_empty()) {
- DOUT << "While deleting: " << *Ty << " %" << getNameStr() << "\n";
+ cerr << "While deleting: " << *VTy << " %" << getNameStr() << "\n";
for (use_iterator I = use_begin(), E = use_end(); I != E; ++I)
- DOUT << "Use still stuck around after Def is destroyed:"
+ cerr << "Use still stuck around after Def is destroyed:"
<< **I << "\n";
}
#endif
/// isUsedInBasicBlock - Return true if this value is used in the specified
/// basic block.
-bool Value::isUsedInBasicBlock(BasicBlock *BB) const {
+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<Instruction>(*I);
if (User && User->getParent() == BB)
// 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!");
+ 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.
// 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
}
Value *Value::stripPointerCasts() {
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
- if (CE->getOpcode() == Instruction::BitCast) {
- if (isa<PointerType>(CE->getOperand(0)->getType()))
- return CE->getOperand(0)->stripPointerCasts();
- } else if (CE->getOpcode() == Instruction::GetElementPtr) {
- for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
- if (!CE->getOperand(i)->isNullValue())
- return this;
- return CE->getOperand(0)->stripPointerCasts();
+ if (!isa<PointerType>(getType()))
+ return this;
+ Value *V = this;
+ do {
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ if (CE->getOpcode() == Instruction::GetElementPtr) {
+ for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
+ if (!CE->getOperand(i)->isNullValue())
+ return V;
+ V = CE->getOperand(0);
+ } else if (CE->getOpcode() == Instruction::BitCast) {
+ V = CE->getOperand(0);
+ } else {
+ return V;
+ }
+ } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) {
+ if (!GEP->hasAllZeroIndices())
+ return V;
+ V = GEP->getOperand(0);
+ } else if (BitCastInst *CI = dyn_cast<BitCastInst>(V)) {
+ V = CI->getOperand(0);
+ } else {
+ return V;
}
+ assert(isa<PointerType>(V->getType()) && "Unexpected operand type!");
+ } while (1);
+}
+
+Value *Value::getUnderlyingObject() {
+ if (!isa<PointerType>(getType()))
return this;
+ Value *V = this;
+ unsigned MaxLookup = 6;
+ do {
+ if (Instruction *I = dyn_cast<Instruction>(V)) {
+ if (!isa<BitCastInst>(I) && !isa<GetElementPtrInst>(I))
+ return V;
+ V = I->getOperand(0);
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ if (CE->getOpcode() != Instruction::BitCast &&
+ CE->getOpcode() != Instruction::GetElementPtr)
+ return V;
+ V = CE->getOperand(0);
+ } else {
+ return V;
+ }
+ assert(isa<PointerType>(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<PHINode>(this);
+ if (PN && PN->getParent() == CurBB)
+ return PN->getIncomingValueForBlock(PredBB);
+ return this;
+}
+
+//===----------------------------------------------------------------------===//
+// 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<Value*, ValueHandleBase*> ValueHandlesTy;
+static ManagedStatic<ValueHandlesTy> ValueHandles;
+static ManagedStatic<sys::SmartRWMutex<true> > 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?");
}
+}
- if (BitCastInst *CI = dyn_cast<BitCastInst>(this)) {
- if (isa<PointerType>(CI->getOperand(0)->getType()))
- return CI->getOperand(0)->stripPointerCasts();
- } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(this)) {
- if (GEP->hasAllZeroIndices())
- return GEP->getOperand(0)->stripPointerCasts();
+/// 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<true> 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<true> 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);
}
- return this;
}
+/// 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<true> 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...
+ cerr << "While deleting: " << *V->getType() << " %" << V->getNameStr()
+ << "\n";
+#endif
+ cerr << "An asserting value handle still pointed to this value!\n";
+ abort();
+ 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<CallbackVH*>(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<CallbackVH*>(ThisNode)->allUsesReplacedWith(New);
+ break;
+ }
+ }
+}
+
+/// ~CallbackVH. Empty, but defined here to avoid emitting the vtable
+/// more than once.
+CallbackVH::~CallbackVH() {}
+
+
//===----------------------------------------------------------------------===//
// User Class
//===----------------------------------------------------------------------===//
}
}
-void *User::operator new(size_t s, unsigned Us) {
- void *Storage = ::operator new(s + sizeof(Use) * Us);
- Use *Start = static_cast<Use*>(Storage);
- Use *End = Start + Us;
- User *Obj = reinterpret_cast<User*>(End);
- Obj->OperandList = Start;
- Obj->NumOperands = Us;
- Use::initTags(Start, End);
- return Obj;
-}
-
-void User::operator delete(void *Usr) {
- User *Start = static_cast<User*>(Usr);
- Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands;
- ::operator delete(Storage == Start->OperandList
- ? Storage
- : Usr);
-}
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