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|
//===--------------- LLVMContextImpl.cpp - Implementation ------*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements LLVMContextImpl, the opaque implementation
// of LLVMContext.
//
//===----------------------------------------------------------------------===//
#include "LLVMContextImpl.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/LLVMContext.h"
#include "llvm/MDNode.h"
using namespace llvm;
static char getValType(ConstantAggregateZero *CPZ) { return 0; }
static std::vector<Constant*> getValType(ConstantArray *CA) {
std::vector<Constant*> Elements;
Elements.reserve(CA->getNumOperands());
for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
Elements.push_back(cast<Constant>(CA->getOperand(i)));
return Elements;
}
static std::vector<Constant*> getValType(ConstantStruct *CS) {
std::vector<Constant*> Elements;
Elements.reserve(CS->getNumOperands());
for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i)
Elements.push_back(cast<Constant>(CS->getOperand(i)));
return Elements;
}
static std::vector<Constant*> getValType(ConstantVector *CP) {
std::vector<Constant*> Elements;
Elements.reserve(CP->getNumOperands());
for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
Elements.push_back(CP->getOperand(i));
return Elements;
}
namespace llvm {
template<typename T, typename Alloc>
struct VISIBILITY_HIDDEN ConstantTraits< std::vector<T, Alloc> > {
static unsigned uses(const std::vector<T, Alloc>& v) {
return v.size();
}
};
template<class ConstantClass, class TypeClass, class ValType>
struct VISIBILITY_HIDDEN ConstantCreator {
static ConstantClass *create(const TypeClass *Ty, const ValType &V) {
return new(ConstantTraits<ValType>::uses(V)) ConstantClass(Ty, V);
}
};
template<class ConstantClass, class TypeClass>
struct VISIBILITY_HIDDEN ConvertConstantType {
static void convert(ConstantClass *OldC, const TypeClass *NewTy) {
llvm_unreachable("This type cannot be converted!");
}
};
// ConstantAggregateZero does not take extra "value" argument...
template<class ValType>
struct ConstantCreator<ConstantAggregateZero, Type, ValType> {
static ConstantAggregateZero *create(const Type *Ty, const ValType &V){
return new ConstantAggregateZero(Ty);
}
};
template<>
struct ConvertConstantType<ConstantAggregateZero, Type> {
static void convert(ConstantAggregateZero *OldC, const Type *NewTy) {
// Make everyone now use a constant of the new type...
Constant *New = NewTy->getContext().getConstantAggregateZero(NewTy);
assert(New != OldC && "Didn't replace constant??");
OldC->uncheckedReplaceAllUsesWith(New);
OldC->destroyConstant(); // This constant is now dead, destroy it.
}
};
template<>
struct ConvertConstantType<ConstantArray, ArrayType> {
static void convert(ConstantArray *OldC, const ArrayType *NewTy) {
// Make everyone now use a constant of the new type...
std::vector<Constant*> C;
for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
C.push_back(cast<Constant>(OldC->getOperand(i)));
Constant *New = NewTy->getContext().getConstantArray(NewTy, C);
assert(New != OldC && "Didn't replace constant??");
OldC->uncheckedReplaceAllUsesWith(New);
OldC->destroyConstant(); // This constant is now dead, destroy it.
}
};
template<>
struct ConvertConstantType<ConstantStruct, StructType> {
static void convert(ConstantStruct *OldC, const StructType *NewTy) {
// Make everyone now use a constant of the new type...
std::vector<Constant*> C;
for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
C.push_back(cast<Constant>(OldC->getOperand(i)));
Constant *New = NewTy->getContext().getConstantStruct(NewTy, C);
assert(New != OldC && "Didn't replace constant??");
OldC->uncheckedReplaceAllUsesWith(New);
OldC->destroyConstant(); // This constant is now dead, destroy it.
}
};
template<>
struct ConvertConstantType<ConstantVector, VectorType> {
static void convert(ConstantVector *OldC, const VectorType *NewTy) {
// Make everyone now use a constant of the new type...
std::vector<Constant*> C;
for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
C.push_back(cast<Constant>(OldC->getOperand(i)));
Constant *New = OldC->getContext().getConstantVector(NewTy, C);
assert(New != OldC && "Didn't replace constant??");
OldC->uncheckedReplaceAllUsesWith(New);
OldC->destroyConstant(); // This constant is now dead, destroy it.
}
};
}
template<class ValType, class TypeClass, class ConstantClass,
bool HasLargeKey /*true for arrays and structs*/ >
class VISIBILITY_HIDDEN ValueMap : public AbstractTypeUser {
public:
typedef std::pair<const Type*, ValType> MapKey;
typedef std::map<MapKey, Constant *> MapTy;
typedef std::map<Constant*, typename MapTy::iterator> InverseMapTy;
typedef std::map<const Type*, typename MapTy::iterator> AbstractTypeMapTy;
private:
/// Map - This is the main map from the element descriptor to the Constants.
/// This is the primary way we avoid creating two of the same shape
/// constant.
MapTy Map;
/// InverseMap - If "HasLargeKey" is true, this contains an inverse mapping
/// from the constants to their element in Map. This is important for
/// removal of constants from the array, which would otherwise have to scan
/// through the map with very large keys.
InverseMapTy InverseMap;
/// AbstractTypeMap - Map for abstract type constants.
///
AbstractTypeMapTy AbstractTypeMap;
/// ValueMapLock - Mutex for this map.
sys::SmartMutex<true> ValueMapLock;
public:
// NOTE: This function is not locked. It is the caller's responsibility
// to enforce proper synchronization.
typename MapTy::iterator map_end() { return Map.end(); }
/// InsertOrGetItem - Return an iterator for the specified element.
/// If the element exists in the map, the returned iterator points to the
/// entry and Exists=true. If not, the iterator points to the newly
/// inserted entry and returns Exists=false. Newly inserted entries have
/// I->second == 0, and should be filled in.
/// NOTE: This function is not locked. It is the caller's responsibility
// to enforce proper synchronization.
typename MapTy::iterator InsertOrGetItem(std::pair<MapKey, Constant *>
&InsertVal,
bool &Exists) {
std::pair<typename MapTy::iterator, bool> IP = Map.insert(InsertVal);
Exists = !IP.second;
return IP.first;
}
private:
typename MapTy::iterator FindExistingElement(ConstantClass *CP) {
if (HasLargeKey) {
typename InverseMapTy::iterator IMI = InverseMap.find(CP);
assert(IMI != InverseMap.end() && IMI->second != Map.end() &&
IMI->second->second == CP &&
"InverseMap corrupt!");
return IMI->second;
}
typename MapTy::iterator I =
Map.find(MapKey(static_cast<const TypeClass*>(CP->getRawType()),
getValType(CP)));
if (I == Map.end() || I->second != CP) {
// FIXME: This should not use a linear scan. If this gets to be a
// performance problem, someone should look at this.
for (I = Map.begin(); I != Map.end() && I->second != CP; ++I)
/* empty */;
}
return I;
}
ConstantClass* Create(const TypeClass *Ty, const ValType &V,
typename MapTy::iterator I) {
ConstantClass* Result =
ConstantCreator<ConstantClass,TypeClass,ValType>::create(Ty, V);
assert(Result->getType() == Ty && "Type specified is not correct!");
I = Map.insert(I, std::make_pair(MapKey(Ty, V), Result));
if (HasLargeKey) // Remember the reverse mapping if needed.
InverseMap.insert(std::make_pair(Result, I));
// If the type of the constant is abstract, make sure that an entry
// exists for it in the AbstractTypeMap.
if (Ty->isAbstract()) {
typename AbstractTypeMapTy::iterator TI =
AbstractTypeMap.find(Ty);
if (TI == AbstractTypeMap.end()) {
// Add ourselves to the ATU list of the type.
cast<DerivedType>(Ty)->addAbstractTypeUser(this);
AbstractTypeMap.insert(TI, std::make_pair(Ty, I));
}
}
return Result;
}
public:
/// getOrCreate - Return the specified constant from the map, creating it if
/// necessary.
ConstantClass *getOrCreate(const TypeClass *Ty, const ValType &V) {
sys::SmartScopedLock<true> Lock(ValueMapLock);
MapKey Lookup(Ty, V);
ConstantClass* Result = 0;
typename MapTy::iterator I = Map.find(Lookup);
// Is it in the map?
if (I != Map.end())
Result = static_cast<ConstantClass *>(I->second);
if (!Result) {
// If no preexisting value, create one now...
Result = Create(Ty, V, I);
}
return Result;
}
void remove(ConstantClass *CP) {
sys::SmartScopedLock<true> Lock(ValueMapLock);
typename MapTy::iterator I = FindExistingElement(CP);
assert(I != Map.end() && "Constant not found in constant table!");
assert(I->second == CP && "Didn't find correct element?");
if (HasLargeKey) // Remember the reverse mapping if needed.
InverseMap.erase(CP);
// Now that we found the entry, make sure this isn't the entry that
// the AbstractTypeMap points to.
const TypeClass *Ty = static_cast<const TypeClass *>(I->first.first);
if (Ty->isAbstract()) {
assert(AbstractTypeMap.count(Ty) &&
"Abstract type not in AbstractTypeMap?");
typename MapTy::iterator &ATMEntryIt = AbstractTypeMap[Ty];
if (ATMEntryIt == I) {
// Yes, we are removing the representative entry for this type.
// See if there are any other entries of the same type.
typename MapTy::iterator TmpIt = ATMEntryIt;
// First check the entry before this one...
if (TmpIt != Map.begin()) {
--TmpIt;
if (TmpIt->first.first != Ty) // Not the same type, move back...
++TmpIt;
}
// If we didn't find the same type, try to move forward...
if (TmpIt == ATMEntryIt) {
++TmpIt;
if (TmpIt == Map.end() || TmpIt->first.first != Ty)
--TmpIt; // No entry afterwards with the same type
}
// If there is another entry in the map of the same abstract type,
// update the AbstractTypeMap entry now.
if (TmpIt != ATMEntryIt) {
ATMEntryIt = TmpIt;
} else {
// Otherwise, we are removing the last instance of this type
// from the table. Remove from the ATM, and from user list.
cast<DerivedType>(Ty)->removeAbstractTypeUser(this);
AbstractTypeMap.erase(Ty);
}
}
}
Map.erase(I);
}
/// MoveConstantToNewSlot - If we are about to change C to be the element
/// specified by I, update our internal data structures to reflect this
/// fact.
/// NOTE: This function is not locked. It is the responsibility of the
/// caller to enforce proper synchronization if using this method.
void MoveConstantToNewSlot(ConstantClass *C, typename MapTy::iterator I) {
// First, remove the old location of the specified constant in the map.
typename MapTy::iterator OldI = FindExistingElement(C);
assert(OldI != Map.end() && "Constant not found in constant table!");
assert(OldI->second == C && "Didn't find correct element?");
// If this constant is the representative element for its abstract type,
// update the AbstractTypeMap so that the representative element is I.
if (C->getType()->isAbstract()) {
typename AbstractTypeMapTy::iterator ATI =
AbstractTypeMap.find(C->getType());
assert(ATI != AbstractTypeMap.end() &&
"Abstract type not in AbstractTypeMap?");
if (ATI->second == OldI)
ATI->second = I;
}
// Remove the old entry from the map.
Map.erase(OldI);
// Update the inverse map so that we know that this constant is now
// located at descriptor I.
if (HasLargeKey) {
assert(I->second == C && "Bad inversemap entry!");
InverseMap[C] = I;
}
}
void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
sys::SmartScopedLock<true> Lock(ValueMapLock);
typename AbstractTypeMapTy::iterator I =
AbstractTypeMap.find(cast<Type>(OldTy));
assert(I != AbstractTypeMap.end() &&
"Abstract type not in AbstractTypeMap?");
// Convert a constant at a time until the last one is gone. The last one
// leaving will remove() itself, causing the AbstractTypeMapEntry to be
// eliminated eventually.
do {
ConvertConstantType<ConstantClass,
TypeClass>::convert(
static_cast<ConstantClass *>(I->second->second),
cast<TypeClass>(NewTy));
I = AbstractTypeMap.find(cast<Type>(OldTy));
} while (I != AbstractTypeMap.end());
}
// If the type became concrete without being refined to any other existing
// type, we just remove ourselves from the ATU list.
void typeBecameConcrete(const DerivedType *AbsTy) {
AbsTy->removeAbstractTypeUser(this);
}
void dump() const {
DOUT << "Constant.cpp: ValueMap\n";
}
};
LLVMContextImpl::LLVMContextImpl(LLVMContext &C) :
Context(C), TheTrueVal(0), TheFalseVal(0) {
AggZeroConstants = new ValueMap<char, Type, ConstantAggregateZero>();
ArrayConstants = new ArrayConstantsTy();
StructConstants = new StructConstantsTy();
VectorConstants = new VectorConstantsTy();
}
LLVMContextImpl::~LLVMContextImpl() {
delete AggZeroConstants;
delete ArrayConstants;
delete StructConstants;
delete VectorConstants;
}
// Get a ConstantInt from an APInt. Note that the value stored in the DenseMap
// as the key, is a DenseMapAPIntKeyInfo::KeyTy which has provided the
// operator== and operator!= to ensure that the DenseMap doesn't attempt to
// compare APInt's of different widths, which would violate an APInt class
// invariant which generates an assertion.
ConstantInt *LLVMContextImpl::getConstantInt(const APInt& V) {
// Get the corresponding integer type for the bit width of the value.
const IntegerType *ITy = Context.getIntegerType(V.getBitWidth());
// get an existing value or the insertion position
DenseMapAPIntKeyInfo::KeyTy Key(V, ITy);
ConstantsLock.reader_acquire();
ConstantInt *&Slot = IntConstants[Key];
ConstantsLock.reader_release();
if (!Slot) {
sys::SmartScopedWriter<true> Writer(ConstantsLock);
ConstantInt *&NewSlot = IntConstants[Key];
if (!Slot) {
NewSlot = new ConstantInt(ITy, V);
}
return NewSlot;
} else {
return Slot;
}
}
ConstantFP *LLVMContextImpl::getConstantFP(const APFloat &V) {
DenseMapAPFloatKeyInfo::KeyTy Key(V);
ConstantsLock.reader_acquire();
ConstantFP *&Slot = FPConstants[Key];
ConstantsLock.reader_release();
if (!Slot) {
sys::SmartScopedWriter<true> Writer(ConstantsLock);
ConstantFP *&NewSlot = FPConstants[Key];
if (!NewSlot) {
const Type *Ty;
if (&V.getSemantics() == &APFloat::IEEEsingle)
Ty = Type::FloatTy;
else if (&V.getSemantics() == &APFloat::IEEEdouble)
Ty = Type::DoubleTy;
else if (&V.getSemantics() == &APFloat::x87DoubleExtended)
Ty = Type::X86_FP80Ty;
else if (&V.getSemantics() == &APFloat::IEEEquad)
Ty = Type::FP128Ty;
else {
assert(&V.getSemantics() == &APFloat::PPCDoubleDouble &&
"Unknown FP format");
Ty = Type::PPC_FP128Ty;
}
NewSlot = new ConstantFP(Ty, V);
}
return NewSlot;
}
return Slot;
}
MDString *LLVMContextImpl::getMDString(const char *StrBegin,
unsigned StrLength) {
sys::SmartScopedWriter<true> Writer(ConstantsLock);
StringMapEntry<MDString *> &Entry =
MDStringCache.GetOrCreateValue(StringRef(StrBegin, StrLength));
MDString *&S = Entry.getValue();
if (!S) S = new MDString(Entry.getKeyData(),
Entry.getKeyLength());
return S;
}
MDNode *LLVMContextImpl::getMDNode(Value*const* Vals, unsigned NumVals) {
FoldingSetNodeID ID;
for (unsigned i = 0; i != NumVals; ++i)
ID.AddPointer(Vals[i]);
ConstantsLock.reader_acquire();
void *InsertPoint;
MDNode *N = MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
ConstantsLock.reader_release();
if (!N) {
sys::SmartScopedWriter<true> Writer(ConstantsLock);
N = MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
if (!N) {
// InsertPoint will have been set by the FindNodeOrInsertPos call.
N = new MDNode(Vals, NumVals);
MDNodeSet.InsertNode(N, InsertPoint);
}
}
return N;
}
ConstantAggregateZero*
LLVMContextImpl::getConstantAggregateZero(const Type *Ty) {
assert((isa<StructType>(Ty) || isa<ArrayType>(Ty) || isa<VectorType>(Ty)) &&
"Cannot create an aggregate zero of non-aggregate type!");
// Implicitly locked.
return AggZeroConstants->getOrCreate(Ty, 0);
}
Constant *LLVMContextImpl::getConstantArray(const ArrayType *Ty,
const std::vector<Constant*> &V) {
// If this is an all-zero array, return a ConstantAggregateZero object
if (!V.empty()) {
Constant *C = V[0];
if (!C->isNullValue()) {
// Implicitly locked.
return ArrayConstants->getOrCreate(Ty, V);
}
for (unsigned i = 1, e = V.size(); i != e; ++i)
if (V[i] != C) {
// Implicitly locked.
return ArrayConstants->getOrCreate(Ty, V);
}
}
return Context.getConstantAggregateZero(Ty);
}
Constant *LLVMContextImpl::getConstantStruct(const StructType *Ty,
const std::vector<Constant*> &V) {
// Create a ConstantAggregateZero value if all elements are zeros...
for (unsigned i = 0, e = V.size(); i != e; ++i)
if (!V[i]->isNullValue())
// Implicitly locked.
return StructConstants->getOrCreate(Ty, V);
return Context.getConstantAggregateZero(Ty);
}
Constant *LLVMContextImpl::getConstantVector(const VectorType *Ty,
const std::vector<Constant*> &V) {
assert(!V.empty() && "Vectors can't be empty");
// If this is an all-undef or alll-zero vector, return a
// ConstantAggregateZero or UndefValue.
Constant *C = V[0];
bool isZero = C->isNullValue();
bool isUndef = isa<UndefValue>(C);
if (isZero || isUndef) {
for (unsigned i = 1, e = V.size(); i != e; ++i)
if (V[i] != C) {
isZero = isUndef = false;
break;
}
}
if (isZero)
return Context.getConstantAggregateZero(Ty);
if (isUndef)
return Context.getUndef(Ty);
// Implicitly locked.
return VectorConstants->getOrCreate(Ty, V);
}
// *** erase methods ***
void LLVMContextImpl::erase(MDString *M) {
sys::SmartScopedWriter<true> Writer(ConstantsLock);
MDStringCache.erase(MDStringCache.find(StringRef(M->StrBegin,
M->length())));
}
void LLVMContextImpl::erase(MDNode *M) {
sys::SmartScopedWriter<true> Writer(ConstantsLock);
MDNodeSet.RemoveNode(M);
}
void LLVMContextImpl::erase(ConstantAggregateZero *Z) {
AggZeroConstants->remove(Z);
}
void LLVMContextImpl::erase(ConstantArray *C) {
ArrayConstants->remove(C);
}
void LLVMContextImpl::erase(ConstantStruct *S) {
StructConstants->remove(S);
}
void LLVMContextImpl::erase(ConstantVector *V) {
VectorConstants->remove(V);
}
// *** RAUW helpers ***
Constant *LLVMContextImpl::replaceUsesOfWithOnConstant(ConstantArray *CA,
Value *From, Value *To, Use *U) {
assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
Constant *ToC = cast<Constant>(To);
std::pair<ArrayConstantsTy::MapKey, Constant*> Lookup;
Lookup.first.first = CA->getType();
Lookup.second = CA;
std::vector<Constant*> &Values = Lookup.first.second;
Values.reserve(CA->getNumOperands()); // Build replacement array.
// Fill values with the modified operands of the constant array. Also,
// compute whether this turns into an all-zeros array.
bool isAllZeros = false;
unsigned NumUpdated = 0;
if (!ToC->isNullValue()) {
for (Use *O = CA->OperandList, *E = CA->OperandList + CA->getNumOperands();
O != E; ++O) {
Constant *Val = cast<Constant>(O->get());
if (Val == From) {
Val = ToC;
++NumUpdated;
}
Values.push_back(Val);
}
} else {
isAllZeros = true;
for (Use *O = CA->OperandList, *E = CA->OperandList + CA->getNumOperands();
O != E; ++O) {
Constant *Val = cast<Constant>(O->get());
if (Val == From) {
Val = ToC;
++NumUpdated;
}
Values.push_back(Val);
if (isAllZeros) isAllZeros = Val->isNullValue();
}
}
Constant *Replacement = 0;
if (isAllZeros) {
Replacement = Context.getConstantAggregateZero(CA->getType());
} else {
// Check to see if we have this array type already.
sys::SmartScopedWriter<true> Writer(ConstantsLock);
bool Exists;
ArrayConstantsTy::MapTy::iterator I =
ArrayConstants->InsertOrGetItem(Lookup, Exists);
if (Exists) {
Replacement = I->second;
} else {
// Okay, the new shape doesn't exist in the system yet. Instead of
// creating a new constant array, inserting it, replaceallusesof'ing the
// old with the new, then deleting the old... just update the current one
// in place!
ArrayConstants->MoveConstantToNewSlot(CA, I);
// Update to the new value. Optimize for the case when we have a single
// operand that we're changing, but handle bulk updates efficiently.
if (NumUpdated == 1) {
unsigned OperandToUpdate = U - CA->OperandList;
assert(CA->getOperand(OperandToUpdate) == From &&
"ReplaceAllUsesWith broken!");
CA->setOperand(OperandToUpdate, ToC);
} else {
for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
if (CA->getOperand(i) == From)
CA->setOperand(i, ToC);
}
return 0;
}
}
return Replacement;
}
Constant *LLVMContextImpl::replaceUsesOfWithOnConstant(ConstantStruct *CS,
Value *From, Value *To, Use *U) {
assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
Constant *ToC = cast<Constant>(To);
unsigned OperandToUpdate = U - CS->OperandList;
assert(CS->getOperand(OperandToUpdate) == From &&
"ReplaceAllUsesWith broken!");
std::pair<StructConstantsTy::MapKey, Constant*> Lookup;
Lookup.first.first = CS->getType();
Lookup.second = CS;
std::vector<Constant*> &Values = Lookup.first.second;
Values.reserve(CS->getNumOperands()); // Build replacement struct.
// Fill values with the modified operands of the constant struct. Also,
// compute whether this turns into an all-zeros struct.
bool isAllZeros = false;
if (!ToC->isNullValue()) {
for (Use *O = CS->OperandList, *E = CS->OperandList + CS->getNumOperands();
O != E; ++O)
Values.push_back(cast<Constant>(O->get()));
} else {
isAllZeros = true;
for (Use *O = CS->OperandList, *E = CS->OperandList + CS->getNumOperands();
O != E; ++O) {
Constant *Val = cast<Constant>(O->get());
Values.push_back(Val);
if (isAllZeros) isAllZeros = Val->isNullValue();
}
}
Values[OperandToUpdate] = ToC;
Constant *Replacement = 0;
if (isAllZeros) {
Replacement = Context.getConstantAggregateZero(CS->getType());
} else {
// Check to see if we have this array type already.
sys::SmartScopedWriter<true> Writer(ConstantsLock);
bool Exists;
StructConstantsTy::MapTy::iterator I =
StructConstants->InsertOrGetItem(Lookup, Exists);
if (Exists) {
Replacement = I->second;
} else {
// Okay, the new shape doesn't exist in the system yet. Instead of
// creating a new constant struct, inserting it, replaceallusesof'ing the
// old with the new, then deleting the old... just update the current one
// in place!
StructConstants->MoveConstantToNewSlot(CS, I);
// Update to the new value.
CS->setOperand(OperandToUpdate, ToC);
return 0;
}
}
assert(Replacement != CS && "I didn't contain From!");
return Replacement;
}
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