1 //===-- Constants.cpp - Implement Constant nodes --------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Constant* classes...
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Constants.h"
15 #include "ConstantFolding.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/GlobalValue.h"
18 #include "llvm/Instructions.h"
19 #include "llvm/SymbolTable.h"
20 #include "llvm/Module.h"
21 #include "llvm/ADT/StringExtras.h"
22 #include "llvm/Support/MathExtras.h"
23 #include "llvm/Support/Compiler.h"
24 #include "llvm/Support/ManagedStatic.h"
29 //===----------------------------------------------------------------------===//
31 //===----------------------------------------------------------------------===//
33 void Constant::destroyConstantImpl() {
34 // When a Constant is destroyed, there may be lingering
35 // references to the constant by other constants in the constant pool. These
36 // constants are implicitly dependent on the module that is being deleted,
37 // but they don't know that. Because we only find out when the CPV is
38 // deleted, we must now notify all of our users (that should only be
39 // Constants) that they are, in fact, invalid now and should be deleted.
41 while (!use_empty()) {
42 Value *V = use_back();
43 #ifndef NDEBUG // Only in -g mode...
44 if (!isa<Constant>(V))
45 std::cerr << "While deleting: " << *this
46 << "\n\nUse still stuck around after Def is destroyed: "
49 assert(isa<Constant>(V) && "References remain to Constant being destroyed");
50 Constant *CV = cast<Constant>(V);
51 CV->destroyConstant();
53 // The constant should remove itself from our use list...
54 assert((use_empty() || use_back() != V) && "Constant not removed!");
57 // Value has no outstanding references it is safe to delete it now...
61 /// canTrap - Return true if evaluation of this constant could trap. This is
62 /// true for things like constant expressions that could divide by zero.
63 bool Constant::canTrap() const {
64 assert(getType()->isFirstClassType() && "Cannot evaluate aggregate vals!");
65 // The only thing that could possibly trap are constant exprs.
66 const ConstantExpr *CE = dyn_cast<ConstantExpr>(this);
67 if (!CE) return false;
69 // ConstantExpr traps if any operands can trap.
70 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
71 if (getOperand(i)->canTrap())
74 // Otherwise, only specific operations can trap.
75 switch (CE->getOpcode()) {
78 case Instruction::UDiv:
79 case Instruction::SDiv:
80 case Instruction::FDiv:
81 case Instruction::URem:
82 case Instruction::SRem:
83 case Instruction::FRem:
84 // Div and rem can trap if the RHS is not known to be non-zero.
85 if (!isa<ConstantInt>(getOperand(1)) || getOperand(1)->isNullValue())
92 // Static constructor to create a '0' constant of arbitrary type...
93 Constant *Constant::getNullValue(const Type *Ty) {
94 switch (Ty->getTypeID()) {
95 case Type::BoolTyID: {
96 static Constant *NullBool = ConstantBool::get(false);
99 case Type::SByteTyID: {
100 static Constant *NullSByte = ConstantInt::get(Type::SByteTy, 0);
103 case Type::UByteTyID: {
104 static Constant *NullUByte = ConstantInt::get(Type::UByteTy, 0);
107 case Type::ShortTyID: {
108 static Constant *NullShort = ConstantInt::get(Type::ShortTy, 0);
111 case Type::UShortTyID: {
112 static Constant *NullUShort = ConstantInt::get(Type::UShortTy, 0);
115 case Type::IntTyID: {
116 static Constant *NullInt = ConstantInt::get(Type::IntTy, 0);
119 case Type::UIntTyID: {
120 static Constant *NullUInt = ConstantInt::get(Type::UIntTy, 0);
123 case Type::LongTyID: {
124 static Constant *NullLong = ConstantInt::get(Type::LongTy, 0);
127 case Type::ULongTyID: {
128 static Constant *NullULong = ConstantInt::get(Type::ULongTy, 0);
132 case Type::FloatTyID: {
133 static Constant *NullFloat = ConstantFP::get(Type::FloatTy, 0);
136 case Type::DoubleTyID: {
137 static Constant *NullDouble = ConstantFP::get(Type::DoubleTy, 0);
141 case Type::PointerTyID:
142 return ConstantPointerNull::get(cast<PointerType>(Ty));
144 case Type::StructTyID:
145 case Type::ArrayTyID:
146 case Type::PackedTyID:
147 return ConstantAggregateZero::get(Ty);
149 // Function, Label, or Opaque type?
150 assert(!"Cannot create a null constant of that type!");
155 // Static constructor to create the maximum constant of an integral type...
156 ConstantIntegral *ConstantIntegral::getMaxValue(const Type *Ty) {
157 switch (Ty->getTypeID()) {
158 case Type::BoolTyID: return ConstantBool::getTrue();
159 case Type::SByteTyID:
160 case Type::ShortTyID:
162 case Type::LongTyID: {
163 // Calculate 011111111111111...
164 unsigned TypeBits = Ty->getPrimitiveSize()*8;
165 int64_t Val = INT64_MAX; // All ones
166 Val >>= 64-TypeBits; // Shift out unwanted 1 bits...
167 return ConstantInt::get(Ty, Val);
170 case Type::UByteTyID:
171 case Type::UShortTyID:
173 case Type::ULongTyID: return getAllOnesValue(Ty);
179 // Static constructor to create the minimum constant for an integral type...
180 ConstantIntegral *ConstantIntegral::getMinValue(const Type *Ty) {
181 switch (Ty->getTypeID()) {
182 case Type::BoolTyID: return ConstantBool::getFalse();
183 case Type::SByteTyID:
184 case Type::ShortTyID:
186 case Type::LongTyID: {
187 // Calculate 1111111111000000000000
188 unsigned TypeBits = Ty->getPrimitiveSize()*8;
189 int64_t Val = -1; // All ones
190 Val <<= TypeBits-1; // Shift over to the right spot
191 return ConstantInt::get(Ty, Val);
194 case Type::UByteTyID:
195 case Type::UShortTyID:
197 case Type::ULongTyID: return ConstantInt::get(Ty, 0);
203 // Static constructor to create an integral constant with all bits set
204 ConstantIntegral *ConstantIntegral::getAllOnesValue(const Type *Ty) {
205 switch (Ty->getTypeID()) {
206 case Type::BoolTyID: return ConstantBool::getTrue();
207 case Type::SByteTyID:
208 case Type::ShortTyID:
210 case Type::LongTyID: return ConstantInt::get(Ty, -1);
212 case Type::UByteTyID:
213 case Type::UShortTyID:
215 case Type::ULongTyID: {
216 // Calculate ~0 of the right type...
217 unsigned TypeBits = Ty->getPrimitiveSize()*8;
218 uint64_t Val = ~0ULL; // All ones
219 Val >>= 64-TypeBits; // Shift out unwanted 1 bits...
220 return ConstantInt::get(Ty, Val);
226 //===----------------------------------------------------------------------===//
227 // ConstantXXX Classes
228 //===----------------------------------------------------------------------===//
230 //===----------------------------------------------------------------------===//
231 // Normal Constructors
233 ConstantIntegral::ConstantIntegral(const Type *Ty, ValueTy VT, uint64_t V)
234 : Constant(Ty, VT, 0, 0), Val(V) {
237 ConstantBool::ConstantBool(bool V)
238 : ConstantIntegral(Type::BoolTy, ConstantBoolVal, uint64_t(V)) {
241 ConstantInt::ConstantInt(const Type *Ty, uint64_t V)
242 : ConstantIntegral(Ty, ConstantIntVal, V) {
245 ConstantFP::ConstantFP(const Type *Ty, double V)
246 : Constant(Ty, ConstantFPVal, 0, 0) {
247 assert(isValueValidForType(Ty, V) && "Value too large for type!");
251 ConstantArray::ConstantArray(const ArrayType *T,
252 const std::vector<Constant*> &V)
253 : Constant(T, ConstantArrayVal, new Use[V.size()], V.size()) {
254 assert(V.size() == T->getNumElements() &&
255 "Invalid initializer vector for constant array");
256 Use *OL = OperandList;
257 for (std::vector<Constant*>::const_iterator I = V.begin(), E = V.end();
260 assert((C->getType() == T->getElementType() ||
262 C->getType()->getTypeID() == T->getElementType()->getTypeID())) &&
263 "Initializer for array element doesn't match array element type!");
268 ConstantArray::~ConstantArray() {
269 delete [] OperandList;
272 ConstantStruct::ConstantStruct(const StructType *T,
273 const std::vector<Constant*> &V)
274 : Constant(T, ConstantStructVal, new Use[V.size()], V.size()) {
275 assert(V.size() == T->getNumElements() &&
276 "Invalid initializer vector for constant structure");
277 Use *OL = OperandList;
278 for (std::vector<Constant*>::const_iterator I = V.begin(), E = V.end();
281 assert((C->getType() == T->getElementType(I-V.begin()) ||
282 ((T->getElementType(I-V.begin())->isAbstract() ||
283 C->getType()->isAbstract()) &&
284 T->getElementType(I-V.begin())->getTypeID() ==
285 C->getType()->getTypeID())) &&
286 "Initializer for struct element doesn't match struct element type!");
291 ConstantStruct::~ConstantStruct() {
292 delete [] OperandList;
296 ConstantPacked::ConstantPacked(const PackedType *T,
297 const std::vector<Constant*> &V)
298 : Constant(T, ConstantPackedVal, new Use[V.size()], V.size()) {
299 Use *OL = OperandList;
300 for (std::vector<Constant*>::const_iterator I = V.begin(), E = V.end();
303 assert((C->getType() == T->getElementType() ||
305 C->getType()->getTypeID() == T->getElementType()->getTypeID())) &&
306 "Initializer for packed element doesn't match packed element type!");
311 ConstantPacked::~ConstantPacked() {
312 delete [] OperandList;
315 /// UnaryConstantExpr - This class is private to Constants.cpp, and is used
316 /// behind the scenes to implement unary constant exprs.
318 class VISIBILITY_HIDDEN UnaryConstantExpr : public ConstantExpr {
321 UnaryConstantExpr(unsigned Opcode, Constant *C, const Type *Ty)
322 : ConstantExpr(Ty, Opcode, &Op, 1), Op(C, this) {}
326 static bool isSetCC(unsigned Opcode) {
327 return Opcode == Instruction::SetEQ || Opcode == Instruction::SetNE ||
328 Opcode == Instruction::SetLT || Opcode == Instruction::SetGT ||
329 Opcode == Instruction::SetLE || Opcode == Instruction::SetGE;
332 /// BinaryConstantExpr - This class is private to Constants.cpp, and is used
333 /// behind the scenes to implement binary constant exprs.
335 class VISIBILITY_HIDDEN BinaryConstantExpr : public ConstantExpr {
338 BinaryConstantExpr(unsigned Opcode, Constant *C1, Constant *C2)
339 : ConstantExpr(isSetCC(Opcode) ? Type::BoolTy : C1->getType(),
341 Ops[0].init(C1, this);
342 Ops[1].init(C2, this);
347 /// SelectConstantExpr - This class is private to Constants.cpp, and is used
348 /// behind the scenes to implement select constant exprs.
350 class VISIBILITY_HIDDEN SelectConstantExpr : public ConstantExpr {
353 SelectConstantExpr(Constant *C1, Constant *C2, Constant *C3)
354 : ConstantExpr(C2->getType(), Instruction::Select, Ops, 3) {
355 Ops[0].init(C1, this);
356 Ops[1].init(C2, this);
357 Ops[2].init(C3, this);
362 /// ExtractElementConstantExpr - This class is private to
363 /// Constants.cpp, and is used behind the scenes to implement
364 /// extractelement constant exprs.
366 class VISIBILITY_HIDDEN ExtractElementConstantExpr : public ConstantExpr {
369 ExtractElementConstantExpr(Constant *C1, Constant *C2)
370 : ConstantExpr(cast<PackedType>(C1->getType())->getElementType(),
371 Instruction::ExtractElement, Ops, 2) {
372 Ops[0].init(C1, this);
373 Ops[1].init(C2, this);
378 /// InsertElementConstantExpr - This class is private to
379 /// Constants.cpp, and is used behind the scenes to implement
380 /// insertelement constant exprs.
382 class VISIBILITY_HIDDEN InsertElementConstantExpr : public ConstantExpr {
385 InsertElementConstantExpr(Constant *C1, Constant *C2, Constant *C3)
386 : ConstantExpr(C1->getType(), Instruction::InsertElement,
388 Ops[0].init(C1, this);
389 Ops[1].init(C2, this);
390 Ops[2].init(C3, this);
395 /// ShuffleVectorConstantExpr - This class is private to
396 /// Constants.cpp, and is used behind the scenes to implement
397 /// shufflevector constant exprs.
399 class VISIBILITY_HIDDEN ShuffleVectorConstantExpr : public ConstantExpr {
402 ShuffleVectorConstantExpr(Constant *C1, Constant *C2, Constant *C3)
403 : ConstantExpr(C1->getType(), Instruction::ShuffleVector,
405 Ops[0].init(C1, this);
406 Ops[1].init(C2, this);
407 Ops[2].init(C3, this);
412 /// GetElementPtrConstantExpr - This class is private to Constants.cpp, and is
413 /// used behind the scenes to implement getelementpr constant exprs.
415 struct VISIBILITY_HIDDEN GetElementPtrConstantExpr : public ConstantExpr {
416 GetElementPtrConstantExpr(Constant *C, const std::vector<Constant*> &IdxList,
418 : ConstantExpr(DestTy, Instruction::GetElementPtr,
419 new Use[IdxList.size()+1], IdxList.size()+1) {
420 OperandList[0].init(C, this);
421 for (unsigned i = 0, E = IdxList.size(); i != E; ++i)
422 OperandList[i+1].init(IdxList[i], this);
424 ~GetElementPtrConstantExpr() {
425 delete [] OperandList;
430 /// ConstantExpr::get* - Return some common constants without having to
431 /// specify the full Instruction::OPCODE identifier.
433 Constant *ConstantExpr::getNeg(Constant *C) {
434 if (!C->getType()->isFloatingPoint())
435 return get(Instruction::Sub, getNullValue(C->getType()), C);
437 return get(Instruction::Sub, ConstantFP::get(C->getType(), -0.0), C);
439 Constant *ConstantExpr::getNot(Constant *C) {
440 assert(isa<ConstantIntegral>(C) && "Cannot NOT a nonintegral type!");
441 return get(Instruction::Xor, C,
442 ConstantIntegral::getAllOnesValue(C->getType()));
444 Constant *ConstantExpr::getAdd(Constant *C1, Constant *C2) {
445 return get(Instruction::Add, C1, C2);
447 Constant *ConstantExpr::getSub(Constant *C1, Constant *C2) {
448 return get(Instruction::Sub, C1, C2);
450 Constant *ConstantExpr::getMul(Constant *C1, Constant *C2) {
451 return get(Instruction::Mul, C1, C2);
453 Constant *ConstantExpr::getUDiv(Constant *C1, Constant *C2) {
454 return get(Instruction::UDiv, C1, C2);
456 Constant *ConstantExpr::getSDiv(Constant *C1, Constant *C2) {
457 return get(Instruction::SDiv, C1, C2);
459 Constant *ConstantExpr::getFDiv(Constant *C1, Constant *C2) {
460 return get(Instruction::FDiv, C1, C2);
462 Constant *ConstantExpr::getURem(Constant *C1, Constant *C2) {
463 return get(Instruction::URem, C1, C2);
465 Constant *ConstantExpr::getSRem(Constant *C1, Constant *C2) {
466 return get(Instruction::SRem, C1, C2);
468 Constant *ConstantExpr::getFRem(Constant *C1, Constant *C2) {
469 return get(Instruction::FRem, C1, C2);
471 Constant *ConstantExpr::getAnd(Constant *C1, Constant *C2) {
472 return get(Instruction::And, C1, C2);
474 Constant *ConstantExpr::getOr(Constant *C1, Constant *C2) {
475 return get(Instruction::Or, C1, C2);
477 Constant *ConstantExpr::getXor(Constant *C1, Constant *C2) {
478 return get(Instruction::Xor, C1, C2);
480 Constant *ConstantExpr::getSetEQ(Constant *C1, Constant *C2) {
481 return get(Instruction::SetEQ, C1, C2);
483 Constant *ConstantExpr::getSetNE(Constant *C1, Constant *C2) {
484 return get(Instruction::SetNE, C1, C2);
486 Constant *ConstantExpr::getSetLT(Constant *C1, Constant *C2) {
487 return get(Instruction::SetLT, C1, C2);
489 Constant *ConstantExpr::getSetGT(Constant *C1, Constant *C2) {
490 return get(Instruction::SetGT, C1, C2);
492 Constant *ConstantExpr::getSetLE(Constant *C1, Constant *C2) {
493 return get(Instruction::SetLE, C1, C2);
495 Constant *ConstantExpr::getSetGE(Constant *C1, Constant *C2) {
496 return get(Instruction::SetGE, C1, C2);
498 Constant *ConstantExpr::getShl(Constant *C1, Constant *C2) {
499 return get(Instruction::Shl, C1, C2);
501 Constant *ConstantExpr::getShr(Constant *C1, Constant *C2) {
502 return get(Instruction::Shr, C1, C2);
505 Constant *ConstantExpr::getUShr(Constant *C1, Constant *C2) {
506 if (C1->getType()->isUnsigned()) return getShr(C1, C2);
507 return getCast(getShr(getCast(C1,
508 C1->getType()->getUnsignedVersion()), C2), C1->getType());
511 Constant *ConstantExpr::getSShr(Constant *C1, Constant *C2) {
512 if (C1->getType()->isSigned()) return getShr(C1, C2);
513 return getCast(getShr(getCast(C1,
514 C1->getType()->getSignedVersion()), C2), C1->getType());
517 /// getWithOperandReplaced - Return a constant expression identical to this
518 /// one, but with the specified operand set to the specified value.
519 Constant *ConstantExpr::getWithOperandReplaced(unsigned OpNo,
520 Constant *Op) const {
521 assert(OpNo < getNumOperands() && "Operand num is out of range!");
522 assert(Op->getType() == getOperand(OpNo)->getType() &&
523 "Replacing operand with value of different type!");
524 if (getOperand(OpNo) == Op)
525 return const_cast<ConstantExpr*>(this);
527 Constant *Op0, *Op1, *Op2;
528 switch (getOpcode()) {
529 case Instruction::Cast:
530 return ConstantExpr::getCast(Op, getType());
531 case Instruction::Select:
532 Op0 = (OpNo == 0) ? Op : getOperand(0);
533 Op1 = (OpNo == 1) ? Op : getOperand(1);
534 Op2 = (OpNo == 2) ? Op : getOperand(2);
535 return ConstantExpr::getSelect(Op0, Op1, Op2);
536 case Instruction::InsertElement:
537 Op0 = (OpNo == 0) ? Op : getOperand(0);
538 Op1 = (OpNo == 1) ? Op : getOperand(1);
539 Op2 = (OpNo == 2) ? Op : getOperand(2);
540 return ConstantExpr::getInsertElement(Op0, Op1, Op2);
541 case Instruction::ExtractElement:
542 Op0 = (OpNo == 0) ? Op : getOperand(0);
543 Op1 = (OpNo == 1) ? Op : getOperand(1);
544 return ConstantExpr::getExtractElement(Op0, Op1);
545 case Instruction::ShuffleVector:
546 Op0 = (OpNo == 0) ? Op : getOperand(0);
547 Op1 = (OpNo == 1) ? Op : getOperand(1);
548 Op2 = (OpNo == 2) ? Op : getOperand(2);
549 return ConstantExpr::getShuffleVector(Op0, Op1, Op2);
550 case Instruction::GetElementPtr: {
551 std::vector<Constant*> Ops;
552 for (unsigned i = 1, e = getNumOperands(); i != e; ++i)
553 Ops.push_back(getOperand(i));
555 return ConstantExpr::getGetElementPtr(Op, Ops);
557 return ConstantExpr::getGetElementPtr(getOperand(0), Ops);
560 assert(getNumOperands() == 2 && "Must be binary operator?");
561 Op0 = (OpNo == 0) ? Op : getOperand(0);
562 Op1 = (OpNo == 1) ? Op : getOperand(1);
563 return ConstantExpr::get(getOpcode(), Op0, Op1);
567 /// getWithOperands - This returns the current constant expression with the
568 /// operands replaced with the specified values. The specified operands must
569 /// match count and type with the existing ones.
570 Constant *ConstantExpr::
571 getWithOperands(const std::vector<Constant*> &Ops) const {
572 assert(Ops.size() == getNumOperands() && "Operand count mismatch!");
573 bool AnyChange = false;
574 for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
575 assert(Ops[i]->getType() == getOperand(i)->getType() &&
576 "Operand type mismatch!");
577 AnyChange |= Ops[i] != getOperand(i);
579 if (!AnyChange) // No operands changed, return self.
580 return const_cast<ConstantExpr*>(this);
582 switch (getOpcode()) {
583 case Instruction::Cast:
584 return ConstantExpr::getCast(Ops[0], getType());
585 case Instruction::Select:
586 return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
587 case Instruction::InsertElement:
588 return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]);
589 case Instruction::ExtractElement:
590 return ConstantExpr::getExtractElement(Ops[0], Ops[1]);
591 case Instruction::ShuffleVector:
592 return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
593 case Instruction::GetElementPtr: {
594 std::vector<Constant*> ActualOps(Ops.begin()+1, Ops.end());
595 return ConstantExpr::getGetElementPtr(Ops[0], ActualOps);
598 assert(getNumOperands() == 2 && "Must be binary operator?");
599 return ConstantExpr::get(getOpcode(), Ops[0], Ops[1]);
604 //===----------------------------------------------------------------------===//
605 // isValueValidForType implementations
607 bool ConstantInt::isValueValidForType(const Type *Ty, int64_t Val) {
608 switch (Ty->getTypeID()) {
610 return false; // These can't be represented as integers!!!
612 case Type::SByteTyID:
613 return (Val <= INT8_MAX && Val >= INT8_MIN);
614 case Type::UByteTyID:
615 return (Val >= 0) && (Val <= UINT8_MAX);
616 case Type::ShortTyID:
617 return (Val <= INT16_MAX && Val >= INT16_MIN);
618 case Type::UShortTyID:
619 return (Val >= 0) && (Val <= UINT16_MAX);
621 return (Val <= int(INT32_MAX) && Val >= int(INT32_MIN));
623 return (Val >= 0) && (Val <= UINT32_MAX);
625 case Type::ULongTyID:
626 return true; // always true, has to fit in largest type
630 bool ConstantFP::isValueValidForType(const Type *Ty, double Val) {
631 switch (Ty->getTypeID()) {
633 return false; // These can't be represented as floating point!
635 // TODO: Figure out how to test if a double can be cast to a float!
636 case Type::FloatTyID:
637 case Type::DoubleTyID:
638 return true; // This is the largest type...
642 //===----------------------------------------------------------------------===//
643 // Factory Function Implementation
645 // ConstantCreator - A class that is used to create constants by
646 // ValueMap*. This class should be partially specialized if there is
647 // something strange that needs to be done to interface to the ctor for the
651 template<class ConstantClass, class TypeClass, class ValType>
652 struct VISIBILITY_HIDDEN ConstantCreator {
653 static ConstantClass *create(const TypeClass *Ty, const ValType &V) {
654 return new ConstantClass(Ty, V);
658 template<class ConstantClass, class TypeClass>
659 struct VISIBILITY_HIDDEN ConvertConstantType {
660 static void convert(ConstantClass *OldC, const TypeClass *NewTy) {
661 assert(0 && "This type cannot be converted!\n");
666 template<class ValType, class TypeClass, class ConstantClass,
667 bool HasLargeKey = false /*true for arrays and structs*/ >
668 class VISIBILITY_HIDDEN ValueMap : public AbstractTypeUser {
670 typedef std::pair<const Type*, ValType> MapKey;
671 typedef std::map<MapKey, Constant *> MapTy;
672 typedef std::map<Constant*, typename MapTy::iterator> InverseMapTy;
673 typedef std::map<const Type*, typename MapTy::iterator> AbstractTypeMapTy;
675 /// Map - This is the main map from the element descriptor to the Constants.
676 /// This is the primary way we avoid creating two of the same shape
680 /// InverseMap - If "HasLargeKey" is true, this contains an inverse mapping
681 /// from the constants to their element in Map. This is important for
682 /// removal of constants from the array, which would otherwise have to scan
683 /// through the map with very large keys.
684 InverseMapTy InverseMap;
686 /// AbstractTypeMap - Map for abstract type constants.
688 AbstractTypeMapTy AbstractTypeMap;
691 void clear(std::vector<Constant *> &Constants) {
692 for(typename MapTy::iterator I = Map.begin(); I != Map.end(); ++I)
693 Constants.push_back(I->second);
695 AbstractTypeMap.clear();
700 typename MapTy::iterator map_end() { return Map.end(); }
702 /// InsertOrGetItem - Return an iterator for the specified element.
703 /// If the element exists in the map, the returned iterator points to the
704 /// entry and Exists=true. If not, the iterator points to the newly
705 /// inserted entry and returns Exists=false. Newly inserted entries have
706 /// I->second == 0, and should be filled in.
707 typename MapTy::iterator InsertOrGetItem(std::pair<MapKey, Constant *>
710 std::pair<typename MapTy::iterator, bool> IP = Map.insert(InsertVal);
716 typename MapTy::iterator FindExistingElement(ConstantClass *CP) {
718 typename InverseMapTy::iterator IMI = InverseMap.find(CP);
719 assert(IMI != InverseMap.end() && IMI->second != Map.end() &&
720 IMI->second->second == CP &&
721 "InverseMap corrupt!");
725 typename MapTy::iterator I =
726 Map.find(MapKey((TypeClass*)CP->getRawType(), getValType(CP)));
727 if (I == Map.end() || I->second != CP) {
728 // FIXME: This should not use a linear scan. If this gets to be a
729 // performance problem, someone should look at this.
730 for (I = Map.begin(); I != Map.end() && I->second != CP; ++I)
737 /// getOrCreate - Return the specified constant from the map, creating it if
739 ConstantClass *getOrCreate(const TypeClass *Ty, const ValType &V) {
740 MapKey Lookup(Ty, V);
741 typename MapTy::iterator I = Map.lower_bound(Lookup);
743 if (I != Map.end() && I->first == Lookup)
744 return static_cast<ConstantClass *>(I->second);
746 // If no preexisting value, create one now...
747 ConstantClass *Result =
748 ConstantCreator<ConstantClass,TypeClass,ValType>::create(Ty, V);
750 /// FIXME: why does this assert fail when loading 176.gcc?
751 //assert(Result->getType() == Ty && "Type specified is not correct!");
752 I = Map.insert(I, std::make_pair(MapKey(Ty, V), Result));
754 if (HasLargeKey) // Remember the reverse mapping if needed.
755 InverseMap.insert(std::make_pair(Result, I));
757 // If the type of the constant is abstract, make sure that an entry exists
758 // for it in the AbstractTypeMap.
759 if (Ty->isAbstract()) {
760 typename AbstractTypeMapTy::iterator TI =
761 AbstractTypeMap.lower_bound(Ty);
763 if (TI == AbstractTypeMap.end() || TI->first != Ty) {
764 // Add ourselves to the ATU list of the type.
765 cast<DerivedType>(Ty)->addAbstractTypeUser(this);
767 AbstractTypeMap.insert(TI, std::make_pair(Ty, I));
773 void remove(ConstantClass *CP) {
774 typename MapTy::iterator I = FindExistingElement(CP);
775 assert(I != Map.end() && "Constant not found in constant table!");
776 assert(I->second == CP && "Didn't find correct element?");
778 if (HasLargeKey) // Remember the reverse mapping if needed.
779 InverseMap.erase(CP);
781 // Now that we found the entry, make sure this isn't the entry that
782 // the AbstractTypeMap points to.
783 const TypeClass *Ty = static_cast<const TypeClass *>(I->first.first);
784 if (Ty->isAbstract()) {
785 assert(AbstractTypeMap.count(Ty) &&
786 "Abstract type not in AbstractTypeMap?");
787 typename MapTy::iterator &ATMEntryIt = AbstractTypeMap[Ty];
788 if (ATMEntryIt == I) {
789 // Yes, we are removing the representative entry for this type.
790 // See if there are any other entries of the same type.
791 typename MapTy::iterator TmpIt = ATMEntryIt;
793 // First check the entry before this one...
794 if (TmpIt != Map.begin()) {
796 if (TmpIt->first.first != Ty) // Not the same type, move back...
800 // If we didn't find the same type, try to move forward...
801 if (TmpIt == ATMEntryIt) {
803 if (TmpIt == Map.end() || TmpIt->first.first != Ty)
804 --TmpIt; // No entry afterwards with the same type
807 // If there is another entry in the map of the same abstract type,
808 // update the AbstractTypeMap entry now.
809 if (TmpIt != ATMEntryIt) {
812 // Otherwise, we are removing the last instance of this type
813 // from the table. Remove from the ATM, and from user list.
814 cast<DerivedType>(Ty)->removeAbstractTypeUser(this);
815 AbstractTypeMap.erase(Ty);
824 /// MoveConstantToNewSlot - If we are about to change C to be the element
825 /// specified by I, update our internal data structures to reflect this
827 void MoveConstantToNewSlot(ConstantClass *C, typename MapTy::iterator I) {
828 // First, remove the old location of the specified constant in the map.
829 typename MapTy::iterator OldI = FindExistingElement(C);
830 assert(OldI != Map.end() && "Constant not found in constant table!");
831 assert(OldI->second == C && "Didn't find correct element?");
833 // If this constant is the representative element for its abstract type,
834 // update the AbstractTypeMap so that the representative element is I.
835 if (C->getType()->isAbstract()) {
836 typename AbstractTypeMapTy::iterator ATI =
837 AbstractTypeMap.find(C->getType());
838 assert(ATI != AbstractTypeMap.end() &&
839 "Abstract type not in AbstractTypeMap?");
840 if (ATI->second == OldI)
844 // Remove the old entry from the map.
847 // Update the inverse map so that we know that this constant is now
848 // located at descriptor I.
850 assert(I->second == C && "Bad inversemap entry!");
855 void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
856 typename AbstractTypeMapTy::iterator I =
857 AbstractTypeMap.find(cast<Type>(OldTy));
859 assert(I != AbstractTypeMap.end() &&
860 "Abstract type not in AbstractTypeMap?");
862 // Convert a constant at a time until the last one is gone. The last one
863 // leaving will remove() itself, causing the AbstractTypeMapEntry to be
864 // eliminated eventually.
866 ConvertConstantType<ConstantClass,
868 static_cast<ConstantClass *>(I->second->second),
869 cast<TypeClass>(NewTy));
871 I = AbstractTypeMap.find(cast<Type>(OldTy));
872 } while (I != AbstractTypeMap.end());
875 // If the type became concrete without being refined to any other existing
876 // type, we just remove ourselves from the ATU list.
877 void typeBecameConcrete(const DerivedType *AbsTy) {
878 AbsTy->removeAbstractTypeUser(this);
882 std::cerr << "Constant.cpp: ValueMap\n";
888 //---- ConstantBool::get*() implementation.
890 ConstantBool *ConstantBool::getTrue() {
891 static ConstantBool *T = 0;
893 return T = new ConstantBool(true);
895 ConstantBool *ConstantBool::getFalse() {
896 static ConstantBool *F = 0;
898 return F = new ConstantBool(false);
901 //---- ConstantInt::get() implementations...
903 static ManagedStatic<ValueMap<uint64_t, Type, ConstantInt> > IntConstants;
905 // Get a ConstantInt from an int64_t. Note here that we canoncialize the value
906 // to a uint64_t value that has been zero extended down to the size of the
907 // integer type of the ConstantInt. This allows the getZExtValue method to
908 // just return the stored value while getSExtValue has to convert back to sign
909 // extended. getZExtValue is more common in LLVM than getSExtValue().
910 ConstantInt *ConstantInt::get(const Type *Ty, int64_t V) {
911 unsigned Size = Ty->getPrimitiveSizeInBits();
912 uint64_t ZeroExtendedCanonicalization = V & (~uint64_t(0UL) >> (64-Size));
913 return IntConstants->getOrCreate(Ty, ZeroExtendedCanonicalization );
916 //---- ConstantFP::get() implementation...
920 struct ConstantCreator<ConstantFP, Type, uint64_t> {
921 static ConstantFP *create(const Type *Ty, uint64_t V) {
922 assert(Ty == Type::DoubleTy);
923 return new ConstantFP(Ty, BitsToDouble(V));
927 struct ConstantCreator<ConstantFP, Type, uint32_t> {
928 static ConstantFP *create(const Type *Ty, uint32_t V) {
929 assert(Ty == Type::FloatTy);
930 return new ConstantFP(Ty, BitsToFloat(V));
935 static ManagedStatic<ValueMap<uint64_t, Type, ConstantFP> > DoubleConstants;
936 static ManagedStatic<ValueMap<uint32_t, Type, ConstantFP> > FloatConstants;
938 bool ConstantFP::isNullValue() const {
939 return DoubleToBits(Val) == 0;
942 bool ConstantFP::isExactlyValue(double V) const {
943 return DoubleToBits(V) == DoubleToBits(Val);
947 ConstantFP *ConstantFP::get(const Type *Ty, double V) {
948 if (Ty == Type::FloatTy) {
949 // Force the value through memory to normalize it.
950 return FloatConstants->getOrCreate(Ty, FloatToBits(V));
952 assert(Ty == Type::DoubleTy);
953 return DoubleConstants->getOrCreate(Ty, DoubleToBits(V));
957 //---- ConstantAggregateZero::get() implementation...
960 // ConstantAggregateZero does not take extra "value" argument...
961 template<class ValType>
962 struct ConstantCreator<ConstantAggregateZero, Type, ValType> {
963 static ConstantAggregateZero *create(const Type *Ty, const ValType &V){
964 return new ConstantAggregateZero(Ty);
969 struct ConvertConstantType<ConstantAggregateZero, Type> {
970 static void convert(ConstantAggregateZero *OldC, const Type *NewTy) {
971 // Make everyone now use a constant of the new type...
972 Constant *New = ConstantAggregateZero::get(NewTy);
973 assert(New != OldC && "Didn't replace constant??");
974 OldC->uncheckedReplaceAllUsesWith(New);
975 OldC->destroyConstant(); // This constant is now dead, destroy it.
980 static ManagedStatic<ValueMap<char, Type,
981 ConstantAggregateZero> > AggZeroConstants;
983 static char getValType(ConstantAggregateZero *CPZ) { return 0; }
985 Constant *ConstantAggregateZero::get(const Type *Ty) {
986 assert((isa<StructType>(Ty) || isa<ArrayType>(Ty) || isa<PackedType>(Ty)) &&
987 "Cannot create an aggregate zero of non-aggregate type!");
988 return AggZeroConstants->getOrCreate(Ty, 0);
991 // destroyConstant - Remove the constant from the constant table...
993 void ConstantAggregateZero::destroyConstant() {
994 AggZeroConstants->remove(this);
995 destroyConstantImpl();
998 //---- ConstantArray::get() implementation...
1002 struct ConvertConstantType<ConstantArray, ArrayType> {
1003 static void convert(ConstantArray *OldC, const ArrayType *NewTy) {
1004 // Make everyone now use a constant of the new type...
1005 std::vector<Constant*> C;
1006 for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
1007 C.push_back(cast<Constant>(OldC->getOperand(i)));
1008 Constant *New = ConstantArray::get(NewTy, C);
1009 assert(New != OldC && "Didn't replace constant??");
1010 OldC->uncheckedReplaceAllUsesWith(New);
1011 OldC->destroyConstant(); // This constant is now dead, destroy it.
1016 static std::vector<Constant*> getValType(ConstantArray *CA) {
1017 std::vector<Constant*> Elements;
1018 Elements.reserve(CA->getNumOperands());
1019 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1020 Elements.push_back(cast<Constant>(CA->getOperand(i)));
1024 typedef ValueMap<std::vector<Constant*>, ArrayType,
1025 ConstantArray, true /*largekey*/> ArrayConstantsTy;
1026 static ManagedStatic<ArrayConstantsTy> ArrayConstants;
1028 Constant *ConstantArray::get(const ArrayType *Ty,
1029 const std::vector<Constant*> &V) {
1030 // If this is an all-zero array, return a ConstantAggregateZero object
1033 if (!C->isNullValue())
1034 return ArrayConstants->getOrCreate(Ty, V);
1035 for (unsigned i = 1, e = V.size(); i != e; ++i)
1037 return ArrayConstants->getOrCreate(Ty, V);
1039 return ConstantAggregateZero::get(Ty);
1042 // destroyConstant - Remove the constant from the constant table...
1044 void ConstantArray::destroyConstant() {
1045 ArrayConstants->remove(this);
1046 destroyConstantImpl();
1049 /// ConstantArray::get(const string&) - Return an array that is initialized to
1050 /// contain the specified string. If length is zero then a null terminator is
1051 /// added to the specified string so that it may be used in a natural way.
1052 /// Otherwise, the length parameter specifies how much of the string to use
1053 /// and it won't be null terminated.
1055 Constant *ConstantArray::get(const std::string &Str, bool AddNull) {
1056 std::vector<Constant*> ElementVals;
1057 for (unsigned i = 0; i < Str.length(); ++i)
1058 ElementVals.push_back(ConstantInt::get(Type::SByteTy, Str[i]));
1060 // Add a null terminator to the string...
1062 ElementVals.push_back(ConstantInt::get(Type::SByteTy, 0));
1065 ArrayType *ATy = ArrayType::get(Type::SByteTy, ElementVals.size());
1066 return ConstantArray::get(ATy, ElementVals);
1069 /// isString - This method returns true if the array is an array of sbyte or
1070 /// ubyte, and if the elements of the array are all ConstantInt's.
1071 bool ConstantArray::isString() const {
1072 // Check the element type for sbyte or ubyte...
1073 if (getType()->getElementType() != Type::UByteTy &&
1074 getType()->getElementType() != Type::SByteTy)
1076 // Check the elements to make sure they are all integers, not constant
1078 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
1079 if (!isa<ConstantInt>(getOperand(i)))
1084 /// isCString - This method returns true if the array is a string (see
1085 /// isString) and it ends in a null byte \0 and does not contains any other
1086 /// null bytes except its terminator.
1087 bool ConstantArray::isCString() const {
1088 // Check the element type for sbyte or ubyte...
1089 if (getType()->getElementType() != Type::UByteTy &&
1090 getType()->getElementType() != Type::SByteTy)
1092 Constant *Zero = Constant::getNullValue(getOperand(0)->getType());
1093 // Last element must be a null.
1094 if (getOperand(getNumOperands()-1) != Zero)
1096 // Other elements must be non-null integers.
1097 for (unsigned i = 0, e = getNumOperands()-1; i != e; ++i) {
1098 if (!isa<ConstantInt>(getOperand(i)))
1100 if (getOperand(i) == Zero)
1107 // getAsString - If the sub-element type of this array is either sbyte or ubyte,
1108 // then this method converts the array to an std::string and returns it.
1109 // Otherwise, it asserts out.
1111 std::string ConstantArray::getAsString() const {
1112 assert(isString() && "Not a string!");
1114 for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
1115 Result += (char)cast<ConstantInt>(getOperand(i))->getZExtValue();
1120 //---- ConstantStruct::get() implementation...
1125 struct ConvertConstantType<ConstantStruct, StructType> {
1126 static void convert(ConstantStruct *OldC, const StructType *NewTy) {
1127 // Make everyone now use a constant of the new type...
1128 std::vector<Constant*> C;
1129 for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
1130 C.push_back(cast<Constant>(OldC->getOperand(i)));
1131 Constant *New = ConstantStruct::get(NewTy, C);
1132 assert(New != OldC && "Didn't replace constant??");
1134 OldC->uncheckedReplaceAllUsesWith(New);
1135 OldC->destroyConstant(); // This constant is now dead, destroy it.
1140 typedef ValueMap<std::vector<Constant*>, StructType,
1141 ConstantStruct, true /*largekey*/> StructConstantsTy;
1142 static ManagedStatic<StructConstantsTy> StructConstants;
1144 static std::vector<Constant*> getValType(ConstantStruct *CS) {
1145 std::vector<Constant*> Elements;
1146 Elements.reserve(CS->getNumOperands());
1147 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i)
1148 Elements.push_back(cast<Constant>(CS->getOperand(i)));
1152 Constant *ConstantStruct::get(const StructType *Ty,
1153 const std::vector<Constant*> &V) {
1154 // Create a ConstantAggregateZero value if all elements are zeros...
1155 for (unsigned i = 0, e = V.size(); i != e; ++i)
1156 if (!V[i]->isNullValue())
1157 return StructConstants->getOrCreate(Ty, V);
1159 return ConstantAggregateZero::get(Ty);
1162 Constant *ConstantStruct::get(const std::vector<Constant*> &V) {
1163 std::vector<const Type*> StructEls;
1164 StructEls.reserve(V.size());
1165 for (unsigned i = 0, e = V.size(); i != e; ++i)
1166 StructEls.push_back(V[i]->getType());
1167 return get(StructType::get(StructEls), V);
1170 // destroyConstant - Remove the constant from the constant table...
1172 void ConstantStruct::destroyConstant() {
1173 StructConstants->remove(this);
1174 destroyConstantImpl();
1177 //---- ConstantPacked::get() implementation...
1181 struct ConvertConstantType<ConstantPacked, PackedType> {
1182 static void convert(ConstantPacked *OldC, const PackedType *NewTy) {
1183 // Make everyone now use a constant of the new type...
1184 std::vector<Constant*> C;
1185 for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
1186 C.push_back(cast<Constant>(OldC->getOperand(i)));
1187 Constant *New = ConstantPacked::get(NewTy, C);
1188 assert(New != OldC && "Didn't replace constant??");
1189 OldC->uncheckedReplaceAllUsesWith(New);
1190 OldC->destroyConstant(); // This constant is now dead, destroy it.
1195 static std::vector<Constant*> getValType(ConstantPacked *CP) {
1196 std::vector<Constant*> Elements;
1197 Elements.reserve(CP->getNumOperands());
1198 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
1199 Elements.push_back(CP->getOperand(i));
1203 static ManagedStatic<ValueMap<std::vector<Constant*>, PackedType,
1204 ConstantPacked> > PackedConstants;
1206 Constant *ConstantPacked::get(const PackedType *Ty,
1207 const std::vector<Constant*> &V) {
1208 // If this is an all-zero packed, return a ConstantAggregateZero object
1211 if (!C->isNullValue())
1212 return PackedConstants->getOrCreate(Ty, V);
1213 for (unsigned i = 1, e = V.size(); i != e; ++i)
1215 return PackedConstants->getOrCreate(Ty, V);
1217 return ConstantAggregateZero::get(Ty);
1220 Constant *ConstantPacked::get(const std::vector<Constant*> &V) {
1221 assert(!V.empty() && "Cannot infer type if V is empty");
1222 return get(PackedType::get(V.front()->getType(),V.size()), V);
1225 // destroyConstant - Remove the constant from the constant table...
1227 void ConstantPacked::destroyConstant() {
1228 PackedConstants->remove(this);
1229 destroyConstantImpl();
1232 //---- ConstantPointerNull::get() implementation...
1236 // ConstantPointerNull does not take extra "value" argument...
1237 template<class ValType>
1238 struct ConstantCreator<ConstantPointerNull, PointerType, ValType> {
1239 static ConstantPointerNull *create(const PointerType *Ty, const ValType &V){
1240 return new ConstantPointerNull(Ty);
1245 struct ConvertConstantType<ConstantPointerNull, PointerType> {
1246 static void convert(ConstantPointerNull *OldC, const PointerType *NewTy) {
1247 // Make everyone now use a constant of the new type...
1248 Constant *New = ConstantPointerNull::get(NewTy);
1249 assert(New != OldC && "Didn't replace constant??");
1250 OldC->uncheckedReplaceAllUsesWith(New);
1251 OldC->destroyConstant(); // This constant is now dead, destroy it.
1256 static ManagedStatic<ValueMap<char, PointerType,
1257 ConstantPointerNull> > NullPtrConstants;
1259 static char getValType(ConstantPointerNull *) {
1264 ConstantPointerNull *ConstantPointerNull::get(const PointerType *Ty) {
1265 return NullPtrConstants->getOrCreate(Ty, 0);
1268 // destroyConstant - Remove the constant from the constant table...
1270 void ConstantPointerNull::destroyConstant() {
1271 NullPtrConstants->remove(this);
1272 destroyConstantImpl();
1276 //---- UndefValue::get() implementation...
1280 // UndefValue does not take extra "value" argument...
1281 template<class ValType>
1282 struct ConstantCreator<UndefValue, Type, ValType> {
1283 static UndefValue *create(const Type *Ty, const ValType &V) {
1284 return new UndefValue(Ty);
1289 struct ConvertConstantType<UndefValue, Type> {
1290 static void convert(UndefValue *OldC, const Type *NewTy) {
1291 // Make everyone now use a constant of the new type.
1292 Constant *New = UndefValue::get(NewTy);
1293 assert(New != OldC && "Didn't replace constant??");
1294 OldC->uncheckedReplaceAllUsesWith(New);
1295 OldC->destroyConstant(); // This constant is now dead, destroy it.
1300 static ManagedStatic<ValueMap<char, Type, UndefValue> > UndefValueConstants;
1302 static char getValType(UndefValue *) {
1307 UndefValue *UndefValue::get(const Type *Ty) {
1308 return UndefValueConstants->getOrCreate(Ty, 0);
1311 // destroyConstant - Remove the constant from the constant table.
1313 void UndefValue::destroyConstant() {
1314 UndefValueConstants->remove(this);
1315 destroyConstantImpl();
1321 //---- ConstantExpr::get() implementations...
1323 typedef std::pair<unsigned, std::vector<Constant*> > ExprMapKeyType;
1327 struct ConstantCreator<ConstantExpr, Type, ExprMapKeyType> {
1328 static ConstantExpr *create(const Type *Ty, const ExprMapKeyType &V) {
1329 if (V.first == Instruction::Cast)
1330 return new UnaryConstantExpr(Instruction::Cast, V.second[0], Ty);
1331 if ((V.first >= Instruction::BinaryOpsBegin &&
1332 V.first < Instruction::BinaryOpsEnd) ||
1333 V.first == Instruction::Shl || V.first == Instruction::Shr)
1334 return new BinaryConstantExpr(V.first, V.second[0], V.second[1]);
1335 if (V.first == Instruction::Select)
1336 return new SelectConstantExpr(V.second[0], V.second[1], V.second[2]);
1337 if (V.first == Instruction::ExtractElement)
1338 return new ExtractElementConstantExpr(V.second[0], V.second[1]);
1339 if (V.first == Instruction::InsertElement)
1340 return new InsertElementConstantExpr(V.second[0], V.second[1],
1342 if (V.first == Instruction::ShuffleVector)
1343 return new ShuffleVectorConstantExpr(V.second[0], V.second[1],
1346 assert(V.first == Instruction::GetElementPtr && "Invalid ConstantExpr!");
1348 std::vector<Constant*> IdxList(V.second.begin()+1, V.second.end());
1349 return new GetElementPtrConstantExpr(V.second[0], IdxList, Ty);
1354 struct ConvertConstantType<ConstantExpr, Type> {
1355 static void convert(ConstantExpr *OldC, const Type *NewTy) {
1357 switch (OldC->getOpcode()) {
1358 case Instruction::Cast:
1359 New = ConstantExpr::getCast(OldC->getOperand(0), NewTy);
1361 case Instruction::Select:
1362 New = ConstantExpr::getSelectTy(NewTy, OldC->getOperand(0),
1363 OldC->getOperand(1),
1364 OldC->getOperand(2));
1366 case Instruction::Shl:
1367 case Instruction::Shr:
1368 New = ConstantExpr::getShiftTy(NewTy, OldC->getOpcode(),
1369 OldC->getOperand(0), OldC->getOperand(1));
1372 assert(OldC->getOpcode() >= Instruction::BinaryOpsBegin &&
1373 OldC->getOpcode() < Instruction::BinaryOpsEnd);
1374 New = ConstantExpr::getTy(NewTy, OldC->getOpcode(), OldC->getOperand(0),
1375 OldC->getOperand(1));
1377 case Instruction::GetElementPtr:
1378 // Make everyone now use a constant of the new type...
1379 std::vector<Value*> Idx(OldC->op_begin()+1, OldC->op_end());
1380 New = ConstantExpr::getGetElementPtrTy(NewTy, OldC->getOperand(0), Idx);
1384 assert(New != OldC && "Didn't replace constant??");
1385 OldC->uncheckedReplaceAllUsesWith(New);
1386 OldC->destroyConstant(); // This constant is now dead, destroy it.
1389 } // end namespace llvm
1392 static ExprMapKeyType getValType(ConstantExpr *CE) {
1393 std::vector<Constant*> Operands;
1394 Operands.reserve(CE->getNumOperands());
1395 for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
1396 Operands.push_back(cast<Constant>(CE->getOperand(i)));
1397 return ExprMapKeyType(CE->getOpcode(), Operands);
1400 static ManagedStatic<ValueMap<ExprMapKeyType, Type,
1401 ConstantExpr> > ExprConstants;
1403 Constant *ConstantExpr::getCast(Constant *C, const Type *Ty) {
1404 assert(Ty->isFirstClassType() && "Cannot cast to an aggregate type!");
1406 if (Constant *FC = ConstantFoldCastInstruction(C, Ty))
1407 return FC; // Fold a few common cases...
1409 // Look up the constant in the table first to ensure uniqueness
1410 std::vector<Constant*> argVec(1, C);
1411 ExprMapKeyType Key = std::make_pair(Instruction::Cast, argVec);
1412 return ExprConstants->getOrCreate(Ty, Key);
1415 Constant *ConstantExpr::getSignExtend(Constant *C, const Type *Ty) {
1416 assert(C->getType()->isIntegral() && Ty->isIntegral() &&
1417 C->getType()->getPrimitiveSize() <= Ty->getPrimitiveSize() &&
1418 "This is an illegal sign extension!");
1419 if (C->getType() != Type::BoolTy) {
1420 C = ConstantExpr::getCast(C, C->getType()->getSignedVersion());
1421 return ConstantExpr::getCast(C, Ty);
1423 if (C == ConstantBool::getTrue())
1424 return ConstantIntegral::getAllOnesValue(Ty);
1426 return ConstantIntegral::getNullValue(Ty);
1430 Constant *ConstantExpr::getZeroExtend(Constant *C, const Type *Ty) {
1431 assert(C->getType()->isIntegral() && Ty->isIntegral() &&
1432 C->getType()->getPrimitiveSize() <= Ty->getPrimitiveSize() &&
1433 "This is an illegal zero extension!");
1434 if (C->getType() != Type::BoolTy)
1435 C = ConstantExpr::getCast(C, C->getType()->getUnsignedVersion());
1436 return ConstantExpr::getCast(C, Ty);
1439 Constant *ConstantExpr::getSizeOf(const Type *Ty) {
1440 // sizeof is implemented as: (ulong) gep (Ty*)null, 1
1442 getGetElementPtr(getNullValue(PointerType::get(Ty)),
1443 std::vector<Constant*>(1, ConstantInt::get(Type::UIntTy, 1))),
1447 Constant *ConstantExpr::getPtrPtrFromArrayPtr(Constant *C) {
1448 // pointer from array is implemented as: getelementptr arr ptr, 0, 0
1449 static std::vector<Constant*> Indices(2, ConstantInt::get(Type::UIntTy, 0));
1451 return ConstantExpr::getGetElementPtr(C, Indices);
1454 Constant *ConstantExpr::getTy(const Type *ReqTy, unsigned Opcode,
1455 Constant *C1, Constant *C2) {
1456 if (Opcode == Instruction::Shl || Opcode == Instruction::Shr)
1457 return getShiftTy(ReqTy, Opcode, C1, C2);
1458 // Check the operands for consistency first
1459 assert(Opcode >= Instruction::BinaryOpsBegin &&
1460 Opcode < Instruction::BinaryOpsEnd &&
1461 "Invalid opcode in binary constant expression");
1462 assert(C1->getType() == C2->getType() &&
1463 "Operand types in binary constant expression should match");
1465 if (ReqTy == C1->getType() || (Instruction::isComparison(Opcode) &&
1466 ReqTy == Type::BoolTy))
1467 if (Constant *FC = ConstantFoldBinaryInstruction(Opcode, C1, C2))
1468 return FC; // Fold a few common cases...
1470 std::vector<Constant*> argVec(1, C1); argVec.push_back(C2);
1471 ExprMapKeyType Key = std::make_pair(Opcode, argVec);
1472 return ExprConstants->getOrCreate(ReqTy, Key);
1475 Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2) {
1478 case Instruction::Add:
1479 case Instruction::Sub:
1480 case Instruction::Mul:
1481 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1482 assert((C1->getType()->isInteger() || C1->getType()->isFloatingPoint() ||
1483 isa<PackedType>(C1->getType())) &&
1484 "Tried to create an arithmetic operation on a non-arithmetic type!");
1486 case Instruction::UDiv:
1487 case Instruction::SDiv:
1488 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1489 assert((C1->getType()->isInteger() || (isa<PackedType>(C1->getType()) &&
1490 cast<PackedType>(C1->getType())->getElementType()->isInteger())) &&
1491 "Tried to create an arithmetic operation on a non-arithmetic type!");
1493 case Instruction::FDiv:
1494 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1495 assert((C1->getType()->isFloatingPoint() || (isa<PackedType>(C1->getType())
1496 && cast<PackedType>(C1->getType())->getElementType()->isFloatingPoint()))
1497 && "Tried to create an arithmetic operation on a non-arithmetic type!");
1499 case Instruction::URem:
1500 case Instruction::SRem:
1501 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1502 assert((C1->getType()->isInteger() || (isa<PackedType>(C1->getType()) &&
1503 cast<PackedType>(C1->getType())->getElementType()->isInteger())) &&
1504 "Tried to create an arithmetic operation on a non-arithmetic type!");
1506 case Instruction::FRem:
1507 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1508 assert((C1->getType()->isFloatingPoint() || (isa<PackedType>(C1->getType())
1509 && cast<PackedType>(C1->getType())->getElementType()->isFloatingPoint()))
1510 && "Tried to create an arithmetic operation on a non-arithmetic type!");
1512 case Instruction::And:
1513 case Instruction::Or:
1514 case Instruction::Xor:
1515 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1516 assert((C1->getType()->isIntegral() || isa<PackedType>(C1->getType())) &&
1517 "Tried to create a logical operation on a non-integral type!");
1519 case Instruction::SetLT: case Instruction::SetGT: case Instruction::SetLE:
1520 case Instruction::SetGE: case Instruction::SetEQ: case Instruction::SetNE:
1521 assert(C1->getType() == C2->getType() && "Op types should be identical!");
1523 case Instruction::Shl:
1524 case Instruction::Shr:
1525 assert(C2->getType() == Type::UByteTy && "Shift should be by ubyte!");
1526 assert((C1->getType()->isInteger() || isa<PackedType>(C1->getType())) &&
1527 "Tried to create a shift operation on a non-integer type!");
1534 if (Instruction::isComparison(Opcode))
1535 return getTy(Type::BoolTy, Opcode, C1, C2);
1537 return getTy(C1->getType(), Opcode, C1, C2);
1540 Constant *ConstantExpr::getSelectTy(const Type *ReqTy, Constant *C,
1541 Constant *V1, Constant *V2) {
1542 assert(C->getType() == Type::BoolTy && "Select condition must be bool!");
1543 assert(V1->getType() == V2->getType() && "Select value types must match!");
1544 assert(V1->getType()->isFirstClassType() && "Cannot select aggregate type!");
1546 if (ReqTy == V1->getType())
1547 if (Constant *SC = ConstantFoldSelectInstruction(C, V1, V2))
1548 return SC; // Fold common cases
1550 std::vector<Constant*> argVec(3, C);
1553 ExprMapKeyType Key = std::make_pair(Instruction::Select, argVec);
1554 return ExprConstants->getOrCreate(ReqTy, Key);
1557 /// getShiftTy - Return a shift left or shift right constant expr
1558 Constant *ConstantExpr::getShiftTy(const Type *ReqTy, unsigned Opcode,
1559 Constant *C1, Constant *C2) {
1560 // Check the operands for consistency first
1561 assert((Opcode == Instruction::Shl ||
1562 Opcode == Instruction::Shr) &&
1563 "Invalid opcode in binary constant expression");
1564 assert(C1->getType()->isIntegral() && C2->getType() == Type::UByteTy &&
1565 "Invalid operand types for Shift constant expr!");
1567 if (Constant *FC = ConstantFoldBinaryInstruction(Opcode, C1, C2))
1568 return FC; // Fold a few common cases...
1570 // Look up the constant in the table first to ensure uniqueness
1571 std::vector<Constant*> argVec(1, C1); argVec.push_back(C2);
1572 ExprMapKeyType Key = std::make_pair(Opcode, argVec);
1573 return ExprConstants->getOrCreate(ReqTy, Key);
1577 Constant *ConstantExpr::getGetElementPtrTy(const Type *ReqTy, Constant *C,
1578 const std::vector<Value*> &IdxList) {
1579 assert(GetElementPtrInst::getIndexedType(C->getType(), IdxList, true) &&
1580 "GEP indices invalid!");
1582 if (Constant *FC = ConstantFoldGetElementPtr(C, IdxList))
1583 return FC; // Fold a few common cases...
1585 assert(isa<PointerType>(C->getType()) &&
1586 "Non-pointer type for constant GetElementPtr expression");
1587 // Look up the constant in the table first to ensure uniqueness
1588 std::vector<Constant*> ArgVec;
1589 ArgVec.reserve(IdxList.size()+1);
1590 ArgVec.push_back(C);
1591 for (unsigned i = 0, e = IdxList.size(); i != e; ++i)
1592 ArgVec.push_back(cast<Constant>(IdxList[i]));
1593 const ExprMapKeyType &Key = std::make_pair(Instruction::GetElementPtr,ArgVec);
1594 return ExprConstants->getOrCreate(ReqTy, Key);
1597 Constant *ConstantExpr::getGetElementPtr(Constant *C,
1598 const std::vector<Constant*> &IdxList){
1599 // Get the result type of the getelementptr!
1600 std::vector<Value*> VIdxList(IdxList.begin(), IdxList.end());
1602 const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), VIdxList,
1604 assert(Ty && "GEP indices invalid!");
1605 return getGetElementPtrTy(PointerType::get(Ty), C, VIdxList);
1608 Constant *ConstantExpr::getGetElementPtr(Constant *C,
1609 const std::vector<Value*> &IdxList) {
1610 // Get the result type of the getelementptr!
1611 const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList,
1613 assert(Ty && "GEP indices invalid!");
1614 return getGetElementPtrTy(PointerType::get(Ty), C, IdxList);
1617 Constant *ConstantExpr::getExtractElementTy(const Type *ReqTy, Constant *Val,
1619 if (Constant *FC = ConstantFoldExtractElementInstruction(Val, Idx))
1620 return FC; // Fold a few common cases...
1621 // Look up the constant in the table first to ensure uniqueness
1622 std::vector<Constant*> ArgVec(1, Val);
1623 ArgVec.push_back(Idx);
1624 const ExprMapKeyType &Key = std::make_pair(Instruction::ExtractElement,ArgVec);
1625 return ExprConstants->getOrCreate(ReqTy, Key);
1628 Constant *ConstantExpr::getExtractElement(Constant *Val, Constant *Idx) {
1629 assert(isa<PackedType>(Val->getType()) &&
1630 "Tried to create extractelement operation on non-packed type!");
1631 assert(Idx->getType() == Type::UIntTy &&
1632 "Extractelement index must be uint type!");
1633 return getExtractElementTy(cast<PackedType>(Val->getType())->getElementType(),
1637 Constant *ConstantExpr::getInsertElementTy(const Type *ReqTy, Constant *Val,
1638 Constant *Elt, Constant *Idx) {
1639 if (Constant *FC = ConstantFoldInsertElementInstruction(Val, Elt, Idx))
1640 return FC; // Fold a few common cases...
1641 // Look up the constant in the table first to ensure uniqueness
1642 std::vector<Constant*> ArgVec(1, Val);
1643 ArgVec.push_back(Elt);
1644 ArgVec.push_back(Idx);
1645 const ExprMapKeyType &Key = std::make_pair(Instruction::InsertElement,ArgVec);
1646 return ExprConstants->getOrCreate(ReqTy, Key);
1649 Constant *ConstantExpr::getInsertElement(Constant *Val, Constant *Elt,
1651 assert(isa<PackedType>(Val->getType()) &&
1652 "Tried to create insertelement operation on non-packed type!");
1653 assert(Elt->getType() == cast<PackedType>(Val->getType())->getElementType()
1654 && "Insertelement types must match!");
1655 assert(Idx->getType() == Type::UIntTy &&
1656 "Insertelement index must be uint type!");
1657 return getInsertElementTy(cast<PackedType>(Val->getType())->getElementType(),
1661 Constant *ConstantExpr::getShuffleVectorTy(const Type *ReqTy, Constant *V1,
1662 Constant *V2, Constant *Mask) {
1663 if (Constant *FC = ConstantFoldShuffleVectorInstruction(V1, V2, Mask))
1664 return FC; // Fold a few common cases...
1665 // Look up the constant in the table first to ensure uniqueness
1666 std::vector<Constant*> ArgVec(1, V1);
1667 ArgVec.push_back(V2);
1668 ArgVec.push_back(Mask);
1669 const ExprMapKeyType &Key = std::make_pair(Instruction::ShuffleVector,ArgVec);
1670 return ExprConstants->getOrCreate(ReqTy, Key);
1673 Constant *ConstantExpr::getShuffleVector(Constant *V1, Constant *V2,
1675 assert(ShuffleVectorInst::isValidOperands(V1, V2, Mask) &&
1676 "Invalid shuffle vector constant expr operands!");
1677 return getShuffleVectorTy(V1->getType(), V1, V2, Mask);
1681 // destroyConstant - Remove the constant from the constant table...
1683 void ConstantExpr::destroyConstant() {
1684 ExprConstants->remove(this);
1685 destroyConstantImpl();
1688 const char *ConstantExpr::getOpcodeName() const {
1689 return Instruction::getOpcodeName(getOpcode());
1692 //===----------------------------------------------------------------------===//
1693 // replaceUsesOfWithOnConstant implementations
1695 void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
1697 assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
1698 Constant *ToC = cast<Constant>(To);
1700 unsigned OperandToUpdate = U-OperandList;
1701 assert(getOperand(OperandToUpdate) == From && "ReplaceAllUsesWith broken!");
1703 std::pair<ArrayConstantsTy::MapKey, Constant*> Lookup;
1704 Lookup.first.first = getType();
1705 Lookup.second = this;
1707 std::vector<Constant*> &Values = Lookup.first.second;
1708 Values.reserve(getNumOperands()); // Build replacement array.
1710 // Fill values with the modified operands of the constant array. Also,
1711 // compute whether this turns into an all-zeros array.
1712 bool isAllZeros = false;
1713 if (!ToC->isNullValue()) {
1714 for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O)
1715 Values.push_back(cast<Constant>(O->get()));
1718 for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
1719 Constant *Val = cast<Constant>(O->get());
1720 Values.push_back(Val);
1721 if (isAllZeros) isAllZeros = Val->isNullValue();
1724 Values[OperandToUpdate] = ToC;
1726 Constant *Replacement = 0;
1728 Replacement = ConstantAggregateZero::get(getType());
1730 // Check to see if we have this array type already.
1732 ArrayConstantsTy::MapTy::iterator I =
1733 ArrayConstants->InsertOrGetItem(Lookup, Exists);
1736 Replacement = I->second;
1738 // Okay, the new shape doesn't exist in the system yet. Instead of
1739 // creating a new constant array, inserting it, replaceallusesof'ing the
1740 // old with the new, then deleting the old... just update the current one
1742 ArrayConstants->MoveConstantToNewSlot(this, I);
1744 // Update to the new value.
1745 setOperand(OperandToUpdate, ToC);
1750 // Otherwise, I do need to replace this with an existing value.
1751 assert(Replacement != this && "I didn't contain From!");
1753 // Everyone using this now uses the replacement.
1754 uncheckedReplaceAllUsesWith(Replacement);
1756 // Delete the old constant!
1760 void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
1762 assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
1763 Constant *ToC = cast<Constant>(To);
1765 unsigned OperandToUpdate = U-OperandList;
1766 assert(getOperand(OperandToUpdate) == From && "ReplaceAllUsesWith broken!");
1768 std::pair<StructConstantsTy::MapKey, Constant*> Lookup;
1769 Lookup.first.first = getType();
1770 Lookup.second = this;
1771 std::vector<Constant*> &Values = Lookup.first.second;
1772 Values.reserve(getNumOperands()); // Build replacement struct.
1775 // Fill values with the modified operands of the constant struct. Also,
1776 // compute whether this turns into an all-zeros struct.
1777 bool isAllZeros = false;
1778 if (!ToC->isNullValue()) {
1779 for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O)
1780 Values.push_back(cast<Constant>(O->get()));
1783 for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
1784 Constant *Val = cast<Constant>(O->get());
1785 Values.push_back(Val);
1786 if (isAllZeros) isAllZeros = Val->isNullValue();
1789 Values[OperandToUpdate] = ToC;
1791 Constant *Replacement = 0;
1793 Replacement = ConstantAggregateZero::get(getType());
1795 // Check to see if we have this array type already.
1797 StructConstantsTy::MapTy::iterator I =
1798 StructConstants->InsertOrGetItem(Lookup, Exists);
1801 Replacement = I->second;
1803 // Okay, the new shape doesn't exist in the system yet. Instead of
1804 // creating a new constant struct, inserting it, replaceallusesof'ing the
1805 // old with the new, then deleting the old... just update the current one
1807 StructConstants->MoveConstantToNewSlot(this, I);
1809 // Update to the new value.
1810 setOperand(OperandToUpdate, ToC);
1815 assert(Replacement != this && "I didn't contain From!");
1817 // Everyone using this now uses the replacement.
1818 uncheckedReplaceAllUsesWith(Replacement);
1820 // Delete the old constant!
1824 void ConstantPacked::replaceUsesOfWithOnConstant(Value *From, Value *To,
1826 assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
1828 std::vector<Constant*> Values;
1829 Values.reserve(getNumOperands()); // Build replacement array...
1830 for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
1831 Constant *Val = getOperand(i);
1832 if (Val == From) Val = cast<Constant>(To);
1833 Values.push_back(Val);
1836 Constant *Replacement = ConstantPacked::get(getType(), Values);
1837 assert(Replacement != this && "I didn't contain From!");
1839 // Everyone using this now uses the replacement.
1840 uncheckedReplaceAllUsesWith(Replacement);
1842 // Delete the old constant!
1846 void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
1848 assert(isa<Constant>(ToV) && "Cannot make Constant refer to non-constant!");
1849 Constant *To = cast<Constant>(ToV);
1851 Constant *Replacement = 0;
1852 if (getOpcode() == Instruction::GetElementPtr) {
1853 std::vector<Constant*> Indices;
1854 Constant *Pointer = getOperand(0);
1855 Indices.reserve(getNumOperands()-1);
1856 if (Pointer == From) Pointer = To;
1858 for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
1859 Constant *Val = getOperand(i);
1860 if (Val == From) Val = To;
1861 Indices.push_back(Val);
1863 Replacement = ConstantExpr::getGetElementPtr(Pointer, Indices);
1864 } else if (getOpcode() == Instruction::Cast) {
1865 assert(getOperand(0) == From && "Cast only has one use!");
1866 Replacement = ConstantExpr::getCast(To, getType());
1867 } else if (getOpcode() == Instruction::Select) {
1868 Constant *C1 = getOperand(0);
1869 Constant *C2 = getOperand(1);
1870 Constant *C3 = getOperand(2);
1871 if (C1 == From) C1 = To;
1872 if (C2 == From) C2 = To;
1873 if (C3 == From) C3 = To;
1874 Replacement = ConstantExpr::getSelect(C1, C2, C3);
1875 } else if (getOpcode() == Instruction::ExtractElement) {
1876 Constant *C1 = getOperand(0);
1877 Constant *C2 = getOperand(1);
1878 if (C1 == From) C1 = To;
1879 if (C2 == From) C2 = To;
1880 Replacement = ConstantExpr::getExtractElement(C1, C2);
1881 } else if (getOpcode() == Instruction::InsertElement) {
1882 Constant *C1 = getOperand(0);
1883 Constant *C2 = getOperand(1);
1884 Constant *C3 = getOperand(1);
1885 if (C1 == From) C1 = To;
1886 if (C2 == From) C2 = To;
1887 if (C3 == From) C3 = To;
1888 Replacement = ConstantExpr::getInsertElement(C1, C2, C3);
1889 } else if (getOpcode() == Instruction::ShuffleVector) {
1890 Constant *C1 = getOperand(0);
1891 Constant *C2 = getOperand(1);
1892 Constant *C3 = getOperand(2);
1893 if (C1 == From) C1 = To;
1894 if (C2 == From) C2 = To;
1895 if (C3 == From) C3 = To;
1896 Replacement = ConstantExpr::getShuffleVector(C1, C2, C3);
1897 } else if (getNumOperands() == 2) {
1898 Constant *C1 = getOperand(0);
1899 Constant *C2 = getOperand(1);
1900 if (C1 == From) C1 = To;
1901 if (C2 == From) C2 = To;
1902 Replacement = ConstantExpr::get(getOpcode(), C1, C2);
1904 assert(0 && "Unknown ConstantExpr type!");
1908 assert(Replacement != this && "I didn't contain From!");
1910 // Everyone using this now uses the replacement.
1911 uncheckedReplaceAllUsesWith(Replacement);
1913 // Delete the old constant!
1918 /// getStringValue - Turn an LLVM constant pointer that eventually points to a
1919 /// global into a string value. Return an empty string if we can't do it.
1920 /// Parameter Chop determines if the result is chopped at the first null
1923 std::string Constant::getStringValue(bool Chop, unsigned Offset) {
1924 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(this)) {
1925 if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
1926 ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
1927 if (Init->isString()) {
1928 std::string Result = Init->getAsString();
1929 if (Offset < Result.size()) {
1930 // If we are pointing INTO The string, erase the beginning...
1931 Result.erase(Result.begin(), Result.begin()+Offset);
1933 // Take off the null terminator, and any string fragments after it.
1935 std::string::size_type NullPos = Result.find_first_of((char)0);
1936 if (NullPos != std::string::npos)
1937 Result.erase(Result.begin()+NullPos, Result.end());
1943 } else if (Constant *C = dyn_cast<Constant>(this)) {
1944 if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
1945 return GV->getStringValue(Chop, Offset);
1946 else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
1947 if (CE->getOpcode() == Instruction::GetElementPtr) {
1948 // Turn a gep into the specified offset.
1949 if (CE->getNumOperands() == 3 &&
1950 cast<Constant>(CE->getOperand(1))->isNullValue() &&
1951 isa<ConstantInt>(CE->getOperand(2))) {
1952 Offset += cast<ConstantInt>(CE->getOperand(2))->getZExtValue();
1953 return CE->getOperand(0)->getStringValue(Chop, Offset);