//
//===----------------------------------------------------------------------===//
+#include "LLVMContextImpl.h"
#include "llvm/Constant.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Operator.h"
#include "llvm/Module.h"
-#include "llvm/Metadata.h"
#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"
#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 <algorithm>
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<Type*>(Ty);
}
-Value::Value(const Type *ty, unsigned scid)
- : SubclassID(scid), HasValueHandle(0), SubclassOptionalData(0),
- SubclassData(0), VTy(checkType(ty)),
+Value::Value(Type *ty, unsigned scid)
+ : SubclassID(scid), HasValueHandle(0),
+ SubclassOptionalData(0), SubclassData(0), VTy((Type*)checkType(ty)),
UseList(0), Name(0) {
+ // FIXME: Why isn't this in the subclass gunk??
if (isa<CallInst>(this) || isa<InvokeInst>(this))
- assert((VTy->isFirstClassType() || VTy == Type::VoidTy ||
- isa<OpaqueType>(ty) || VTy->getTypeID() == Type::StructTyID) &&
- "invalid CallInst type!");
+ assert((VTy->isFirstClassType() || VTy->isVoidTy() || VTy->isStructTy()) &&
+ "invalid CallInst type!");
else if (!isa<Constant>(this) && !isa<BasicBlock>(this))
- assert((VTy->isFirstClassType() || VTy == Type::VoidTy ||
- isa<OpaqueType>(ty)) &&
+ assert((VTy->isFirstClassType() || VTy->isVoidTy()) &&
"Cannot create non-first-class values except for constants!");
}
// 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()) {
- errs() << "While deleting: " << *VTy << " %" << getNameStr() << "\n";
+ dbgs() << "While deleting: " << *VTy << " %" << getNameStr() << "\n";
for (use_iterator I = use_begin(), E = use_end(); I != E; ++I)
- errs() << "Use still stuck around after Def is destroyed:"
+ dbgs() << "Use still stuck around after Def is destroyed:"
<< **I << "\n";
}
#endif
// at this point.
if (Name)
Name->Destroy();
-
+
// There should be no uses of this object anymore, remove it.
LeakDetector::removeGarbageObject(this);
}
/// hasNUses - Return true if this Value has exactly N users.
///
bool Value::hasNUses(unsigned N) const {
- use_const_iterator UI = use_begin(), E = use_end();
+ const_use_iterator UI = use_begin(), E = use_end();
for (; N; --N, ++UI)
if (UI == E) return false; // Too few.
/// logically equivalent to getNumUses() >= N.
///
bool Value::hasNUsesOrMore(unsigned N) const {
- use_const_iterator UI = use_begin(), E = use_end();
+ const_use_iterator UI = use_begin(), E = use_end();
for (; N; --N, ++UI)
if (UI == E) return false; // Too few.
/// 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) {
+ for (const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
const Instruction *User = dyn_cast<Instruction>(*I);
if (User && User->getParent() == BB)
return true;
if (Function *PP = P->getParent())
ST = &PP->getValueSymbolTable();
} else if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
- if (Function *P = BB->getParent())
+ if (Function *P = BB->getParent())
ST = &P->getValueSymbolTable();
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
- if (Module *P = GV->getParent())
+ if (Module *P = GV->getParent())
ST = &P->getValueSymbolTable();
} else if (Argument *A = dyn_cast<Argument>(V)) {
- if (Function *P = A->getParent())
- ST = &P->getValueSymbolTable();
- } else if (NamedMDNode *N = dyn_cast<NamedMDNode>(V)) {
- if (Module *P = N->getParent()) {
+ if (Function *P = A->getParent())
ST = &P->getValueSymbolTable();
- }
} else if (isa<MDString>(V))
return true;
else {
}
void Value::setName(const Twine &NewName) {
- SmallString<32> NameData;
- NewName.toVector(NameData);
+ // Fast path for common IRBuilder case of setName("") when there is no name.
+ if (NewName.isTriviallyEmpty() && !hasName())
+ return;
- const char *NameStr = NameData.data();
- unsigned NameLen = NameData.size();
+ SmallString<256> NameData;
+ StringRef NameRef = NewName.toStringRef(NameData);
// Name isn't changing?
- if (getName() == StringRef(NameStr, NameLen))
+ if (getName() == NameRef)
return;
- assert(getType() != Type::VoidTy && "Cannot assign a name to void values!");
-
+ assert(!getType()->isVoidTy() && "Cannot assign a name to void values!");
+
// Get the symbol table to update for this object.
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) {
+ if (NameRef.empty()) {
// Free the name for this value.
Name->Destroy();
Name = 0;
return;
}
-
+
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 = ValueName::Create(NameRef.begin(), NameRef.end());
Name->setValue(this);
return;
}
-
+
// NOTE: Could optimize for the case the name is shrinking to not deallocate
// then reallocated.
if (hasName()) {
Name->Destroy();
Name = 0;
- if (NameLen == 0)
+ if (NameRef.empty())
return;
}
// Name is changing to something new.
- Name = ST->createValueName(StringRef(NameStr, NameLen), this);
+ Name = ST->createValueName(NameRef, 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).
+/// 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 (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)) {
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;
-
+ 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.
if (ST == VST) {
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
-// 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(<null>) 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
U.set(New);
}
-}
-
-void Value::replaceAllUsesWith(Value *New) {
- assert(New && "Value::replaceAllUsesWith(<null>) 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<BasicBlock>(this))
+ BB->replaceSuccessorsPhiUsesWith(cast<BasicBlock>(New));
}
Value *Value::stripPointerCasts() {
- if (!isa<PointerType>(getType()))
+ if (!getType()->isPointerTy())
return this;
+
+ // Even though we don't look through PHI nodes, we could be called on an
+ // instruction in an unreachable block, which may be on a cycle.
+ SmallPtrSet<Value *, 4> Visited;
+
Value *V = this;
+ Visited.insert(V);
do {
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
if (!GEP->hasAllZeroIndices())
V = GEP->getPointerOperand();
} else if (Operator::getOpcode(V) == Instruction::BitCast) {
V = cast<Operator>(V)->getOperand(0);
+ } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
+ if (GA->mayBeOverridden())
+ return V;
+ V = GA->getAliasee();
} else {
return V;
}
- assert(isa<PointerType>(V->getType()) && "Unexpected operand type!");
- } while (1);
+ assert(V->getType()->isPointerTy() && "Unexpected operand type!");
+ } while (Visited.insert(V));
+
+ return V;
}
-Value *Value::getUnderlyingObject() {
- if (!isa<PointerType>(getType()))
- return this;
- Value *V = this;
- unsigned MaxLookup = 6;
- do {
- if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
- V = GEP->getPointerOperand();
- } else if (Operator::getOpcode(V) == Instruction::BitCast) {
- V = cast<Operator>(V)->getOperand(0);
- } 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<AllocaInst>(this)) return true;
+
+ // Global variables which can't collapse to null are ok.
+ if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
+ return !GV->hasExternalWeakLinkage();
+
+ // byval arguments are ok.
+ if (const Argument *A = dyn_cast<Argument>(this))
+ return A->hasByValAttr();
+
+ // For GEPs, determine if the indexing lands within the allocated object.
+ if (const GEPOperator *GEP = dyn_cast<GEPOperator>(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<StructType>(Ty))
+ continue;
+ ConstantInt *CI = dyn_cast<ConstantInt>(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<ArrayType>(Ty);
+ if (!ATy)
+ return false;
+ if (CI->getValue().getActiveBits() > 64)
+ return false;
+ if (CI->getZExtValue() >= ATy->getNumElements())
+ return false;
}
- assert(isa<PointerType>(V->getType()) && "Unexpected operand type!");
- } while (--MaxLookup);
- return V;
+ // Indices check out; this is dereferenceable.
+ return true;
+ }
+
+ // If we don't know, assume the worst.
+ return false;
}
/// 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,
+Value *Value::DoPHITranslation(const BasicBlock *CurBB,
const BasicBlock *PredBB) {
PHINode *PN = dyn_cast<PHINode>(this);
if (PN && PN->getParent() == CurBB)
// 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;
}
}
+void ValueHandleBase::AddToExistingUseListAfter(ValueHandleBase *List) {
+ assert(List && "Must insert after existing node");
+
+ Next = List->Next;
+ setPrevPtr(&List->Next);
+ List->Next = this;
+ if (Next)
+ Next->setPrevPtr(&Next);
+}
+
/// AddToUseList - Add this ValueHandle to the use list for VP.
void ValueHandleBase::AddToUseList() {
assert(VP && "Null pointer doesn't have a use list!");
+
+ LLVMContextImpl *pImpl = VP->getContext().pImpl;
+
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];
+ ValueHandleBase *&Entry = pImpl->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;
+ DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->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) ||
+ 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) {
+ for (DenseMap<Value*, ValueHandleBase*>::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);
}
// 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;
+ LLVMContextImpl *pImpl = VP->getContext().pImpl;
+ DenseMap<Value*, ValueHandleBase*> &Handles = pImpl->ValueHandles;
if (Handles.isPointerIntoBucketsArray(PrevPtr)) {
Handles.erase(VP);
VP->HasValueHandle = false;
// 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();
+ LLVMContextImpl *pImpl = V->getContext().pImpl;
+ ValueHandleBase *Entry = pImpl->ValueHandles[V];
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()) {
+
+ // 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);
+ assert(Entry->Next == &Iterator && "Loop invariant broken.");
+
+ switch (Entry->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!");
+ break;
+ case Tracking:
+ // Mark that this value has been deleted by setting it to an invalid Value
+ // pointer.
+ Entry->operator=(DenseMapInfo<Value *>::getTombstoneKey());
+ break;
case Weak:
// Weak just goes to null, which will unlink it from the list.
- ThisNode->operator=(0);
+ Entry->operator=(0);
break;
case Callback:
// Forward to the subclass's implementation.
- static_cast<CallbackVH*>(ThisNode)->deleted();
+ static_cast<CallbackVH*>(Entry)->deleted();
break;
}
}
-
- // All callbacks and weak references should be dropped by now.
- assert(!V->HasValueHandle && "All references to V were not removed?");
+
+ // All callbacks, weak references, and assertingVHs should be dropped by now.
+ if (V->HasValueHandle) {
+#ifndef NDEBUG // Only in +Asserts mode...
+ dbgs() << "While deleting: " << *V->getType() << " %" << V->getNameStr()
+ << "\n";
+ if (pImpl->ValueHandles[V]->getKind() == Assert)
+ llvm_unreachable("An asserting value handle still pointed to this"
+ " value!");
+
+#endif
+ llvm_unreachable("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();
+ LLVMContextImpl *pImpl = Old->getContext().pImpl;
+ ValueHandleBase *Entry = pImpl->ValueHandles[Old];
+
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()) {
+
+ // 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.
+ for (ValueHandleBase Iterator(Assert, *Entry); Entry; Entry = Iterator.Next) {
+ Iterator.RemoveFromUseList();
+ Iterator.AddToExistingUseListAfter(Entry);
+ assert(Entry->Next == &Iterator && "Loop invariant broken.");
+
+ switch (Entry->getKind()) {
case Assert:
// Asserting handle does not follow RAUW implicitly.
break;
+ case Tracking:
+ // Tracking goes to new value like a WeakVH. Note that this may make it
+ // something incompatible with its templated type. We don't want to have a
+ // virtual (or inline) interface to handle this though, so instead we make
+ // the TrackingVH accessors guarantee that a client never sees this value.
+
+ // FALLTHROUGH
case Weak:
// Weak goes to the new value, which will unlink it from Old's list.
- ThisNode->operator=(New);
+ Entry->operator=(New);
break;
case Callback:
// Forward to the subclass's implementation.
- static_cast<CallbackVH*>(ThisNode)->allUsesReplacedWith(New);
+ static_cast<CallbackVH*>(Entry)->allUsesReplacedWith(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<Constant>(this) || isa<GlobalValue>(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...
- }
-}