1 //===-- DataLayout.cpp - Data size & alignment routines --------------------==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines layout properties related to datatype size/offset/alignment
13 // This structure should be created once, filled in if the defaults are not
14 // correct and then passed around by const&. None of the members functions
15 // require modification to the object.
17 //===----------------------------------------------------------------------===//
19 #include "llvm/DataLayout.h"
20 #include "llvm/Constants.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Module.h"
23 #include "llvm/Support/GetElementPtrTypeIterator.h"
24 #include "llvm/Support/MathExtras.h"
25 #include "llvm/Support/ManagedStatic.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include "llvm/Support/Mutex.h"
29 #include "llvm/ADT/DenseMap.h"
34 // Handle the Pass registration stuff necessary to use DataLayout's.
36 // Register the default SparcV9 implementation...
37 INITIALIZE_PASS(DataLayout, "datalayout", "Data Layout", false, true)
38 char DataLayout::ID = 0;
40 //===----------------------------------------------------------------------===//
41 // Support for StructLayout
42 //===----------------------------------------------------------------------===//
44 StructLayout::StructLayout(StructType *ST, const DataLayout &TD) {
45 assert(!ST->isOpaque() && "Cannot get layout of opaque structs");
48 NumElements = ST->getNumElements();
50 // Loop over each of the elements, placing them in memory.
51 for (unsigned i = 0, e = NumElements; i != e; ++i) {
52 Type *Ty = ST->getElementType(i);
53 unsigned TyAlign = ST->isPacked() ? 1 : TD.getABITypeAlignment(Ty);
55 // Add padding if necessary to align the data element properly.
56 if ((StructSize & (TyAlign-1)) != 0)
57 StructSize = DataLayout::RoundUpAlignment(StructSize, TyAlign);
59 // Keep track of maximum alignment constraint.
60 StructAlignment = std::max(TyAlign, StructAlignment);
62 MemberOffsets[i] = StructSize;
63 StructSize += TD.getTypeAllocSize(Ty); // Consume space for this data item
66 // Empty structures have alignment of 1 byte.
67 if (StructAlignment == 0) StructAlignment = 1;
69 // Add padding to the end of the struct so that it could be put in an array
70 // and all array elements would be aligned correctly.
71 if ((StructSize & (StructAlignment-1)) != 0)
72 StructSize = DataLayout::RoundUpAlignment(StructSize, StructAlignment);
76 /// getElementContainingOffset - Given a valid offset into the structure,
77 /// return the structure index that contains it.
78 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
80 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
81 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
83 assert(*SI <= Offset && "upper_bound didn't work");
84 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
85 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
86 "Upper bound didn't work!");
88 // Multiple fields can have the same offset if any of them are zero sized.
89 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
90 // at the i32 element, because it is the last element at that offset. This is
91 // the right one to return, because anything after it will have a higher
92 // offset, implying that this element is non-empty.
93 return SI-&MemberOffsets[0];
96 //===----------------------------------------------------------------------===//
97 // LayoutAlignElem, LayoutAlign support
98 //===----------------------------------------------------------------------===//
101 LayoutAlignElem::get(AlignTypeEnum align_type, unsigned abi_align,
102 unsigned pref_align, uint32_t bit_width) {
103 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
104 LayoutAlignElem retval;
105 retval.AlignType = align_type;
106 retval.ABIAlign = abi_align;
107 retval.PrefAlign = pref_align;
108 retval.TypeBitWidth = bit_width;
113 LayoutAlignElem::operator==(const LayoutAlignElem &rhs) const {
114 return (AlignType == rhs.AlignType
115 && ABIAlign == rhs.ABIAlign
116 && PrefAlign == rhs.PrefAlign
117 && TypeBitWidth == rhs.TypeBitWidth);
120 const LayoutAlignElem
121 DataLayout::InvalidAlignmentElem =
122 LayoutAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
124 //===----------------------------------------------------------------------===//
125 // PointerAlignElem, PointerAlign support
126 //===----------------------------------------------------------------------===//
129 PointerAlignElem::get(uint32_t addr_space, unsigned abi_align,
130 unsigned pref_align, uint32_t bit_width) {
131 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
132 PointerAlignElem retval;
133 retval.AddressSpace = addr_space;
134 retval.ABIAlign = abi_align;
135 retval.PrefAlign = pref_align;
136 retval.TypeBitWidth = bit_width;
141 PointerAlignElem::operator==(const PointerAlignElem &rhs) const {
142 return (ABIAlign == rhs.ABIAlign
143 && AddressSpace == rhs.AddressSpace
144 && PrefAlign == rhs.PrefAlign
145 && TypeBitWidth == rhs.TypeBitWidth);
148 const PointerAlignElem
149 DataLayout::InvalidPointerElem = PointerAlignElem::get(~0U, 0U, 0U, 0U);
151 //===----------------------------------------------------------------------===//
152 // DataLayout Class Implementation
153 //===----------------------------------------------------------------------===//
155 void DataLayout::init(StringRef Desc) {
156 initializeDataLayoutPass(*PassRegistry::getPassRegistry());
159 LittleEndian = false;
160 StackNaturalAlign = 0;
162 // Default alignments
163 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
164 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
165 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
166 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
167 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
168 setAlignment(FLOAT_ALIGN, 2, 2, 16); // half
169 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
170 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
171 setAlignment(FLOAT_ALIGN, 16, 16, 128); // ppcf128, quad, ...
172 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32, v1i64, ...
173 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
174 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct
175 setPointerAlignment(0, 8, 8, 8);
177 std::string errMsg = parseSpecifier(Desc);
178 assert(errMsg == "" && "Invalid target data layout string.");
182 /// Get an unsinged integer, including error checks.
183 static unsigned getInt(StringRef R) {
187 bool error = R.getAsInteger(10, Result);
188 assert(!error && "not a number, or does not fit in an unsigned int");
192 std::string DataLayout::parseSpecifier(StringRef Desc) {
194 while (!Desc.empty()) {
195 std::pair<StringRef, StringRef> Split = Desc.split('-');
196 StringRef Token = Split.first;
199 Split = Token.split(':');
200 StringRef Specifier = Split.first;
201 Token = Split.second;
203 assert(!Specifier.empty() && "Can't be empty here");
205 switch (Specifier[0]) {
207 LittleEndian = false;
213 unsigned AddrSpace = 0;
214 if (Specifier.size() > 1) {
215 AddrSpace = getInt(Specifier.substr(1));
216 if (AddrSpace > (1 << 24))
217 return "Invalid address space, must be a 24bit integer";
219 Split = Token.split(':');
220 unsigned PointerMemSizeBits = getInt(Split.first);
221 if (PointerMemSizeBits % 8 != 0)
222 return "invalid pointer size, must be an 8-bit multiple";
224 // Pointer ABI alignment.
225 Split = Split.second.split(':');
226 unsigned PointerABIAlignBits = getInt(Split.first);
227 if (PointerABIAlignBits % 8 != 0) {
228 return "invalid pointer ABI alignment, "
229 "must be an 8-bit multiple";
232 // Pointer preferred alignment.
233 Split = Split.second.split(':');
234 unsigned PointerPrefAlignBits = getInt(Split.first);
235 if (PointerPrefAlignBits % 8 != 0) {
236 return "invalid pointer preferred alignment, "
237 "must be an 8-bit multiple";
240 if (PointerPrefAlignBits == 0)
241 PointerPrefAlignBits = PointerABIAlignBits;
242 setPointerAlignment(AddrSpace, PointerABIAlignBits/8,
243 PointerPrefAlignBits/8, PointerMemSizeBits/8);
251 AlignTypeEnum AlignType;
252 char field = Specifier[0];
255 case 'i': AlignType = INTEGER_ALIGN; break;
256 case 'v': AlignType = VECTOR_ALIGN; break;
257 case 'f': AlignType = FLOAT_ALIGN; break;
258 case 'a': AlignType = AGGREGATE_ALIGN; break;
259 case 's': AlignType = STACK_ALIGN; break;
261 unsigned Size = getInt(Specifier.substr(1));
263 Split = Token.split(':');
264 unsigned ABIAlignBits = getInt(Split.first);
265 if (ABIAlignBits % 8 != 0) {
266 return std::string("invalid ") + field +"-abi-alignment field, "
267 "must be an 8-bit multiple";
269 unsigned ABIAlign = ABIAlignBits / 8;
271 Split = Split.second.split(':');
273 unsigned PrefAlignBits = getInt(Split.first);
274 if (PrefAlignBits % 8 != 0) {
275 return std::string("invalid ") + field +"-preferred-alignment field, "
276 "must be an 8-bit multiple";
278 unsigned PrefAlign = PrefAlignBits / 8;
280 PrefAlign = ABIAlign;
281 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
285 case 'n': // Native integer types.
286 Specifier = Specifier.substr(1);
288 unsigned Width = getInt(Specifier);
290 return std::string("invalid native integer size \'") +
291 Specifier.str() + "\', must be a non-zero integer.";
293 LegalIntWidths.push_back(Width);
294 Split = Token.split(':');
295 Specifier = Split.first;
296 Token = Split.second;
297 } while (!Specifier.empty() || !Token.empty());
299 case 'S': { // Stack natural alignment.
300 unsigned StackNaturalAlignBits = getInt(Specifier.substr(1));
301 if (StackNaturalAlignBits % 8 != 0) {
302 return "invalid natural stack alignment (S-field), "
303 "must be an 8-bit multiple";
305 StackNaturalAlign = StackNaturalAlignBits / 8;
318 /// @note This has to exist, because this is a pass, but it should never be
320 DataLayout::DataLayout() : ImmutablePass(ID) {
321 report_fatal_error("Bad DataLayout ctor used. "
322 "Tool did not specify a DataLayout to use?");
325 DataLayout::DataLayout(const Module *M)
326 : ImmutablePass(ID) {
327 init(M->getDataLayout());
331 DataLayout::setAlignment(AlignTypeEnum align_type, unsigned abi_align,
332 unsigned pref_align, uint32_t bit_width) {
333 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
334 assert(pref_align < (1 << 16) && "Alignment doesn't fit in bitfield");
335 assert(bit_width < (1 << 24) && "Bit width doesn't fit in bitfield");
336 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
337 if (Alignments[i].AlignType == (unsigned)align_type &&
338 Alignments[i].TypeBitWidth == bit_width) {
339 // Update the abi, preferred alignments.
340 Alignments[i].ABIAlign = abi_align;
341 Alignments[i].PrefAlign = pref_align;
346 Alignments.push_back(LayoutAlignElem::get(align_type, abi_align,
347 pref_align, bit_width));
351 DataLayout::setPointerAlignment(uint32_t addr_space, unsigned abi_align,
352 unsigned pref_align, uint32_t bit_width) {
353 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
354 DenseMap<unsigned,PointerAlignElem>::iterator val = Pointers.find(addr_space);
355 if (val == Pointers.end()) {
356 Pointers[addr_space] = PointerAlignElem::get(addr_space,
357 abi_align, pref_align, bit_width);
359 val->second.ABIAlign = abi_align;
360 val->second.PrefAlign = pref_align;
361 val->second.TypeBitWidth = bit_width;
365 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
366 /// preferred if ABIInfo = false) the layout wants for the specified datatype.
367 unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
368 uint32_t BitWidth, bool ABIInfo,
370 // Check to see if we have an exact match and remember the best match we see.
371 int BestMatchIdx = -1;
373 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
374 if (Alignments[i].AlignType == (unsigned)AlignType &&
375 Alignments[i].TypeBitWidth == BitWidth)
376 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
378 // The best match so far depends on what we're looking for.
379 if (AlignType == INTEGER_ALIGN &&
380 Alignments[i].AlignType == INTEGER_ALIGN) {
381 // The "best match" for integers is the smallest size that is larger than
382 // the BitWidth requested.
383 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
384 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
386 // However, if there isn't one that's larger, then we must use the
387 // largest one we have (see below)
388 if (LargestInt == -1 ||
389 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
394 // Okay, we didn't find an exact solution. Fall back here depending on what
395 // is being looked for.
396 if (BestMatchIdx == -1) {
397 // If we didn't find an integer alignment, fall back on most conservative.
398 if (AlignType == INTEGER_ALIGN) {
399 BestMatchIdx = LargestInt;
401 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
403 // By default, use natural alignment for vector types. This is consistent
404 // with what clang and llvm-gcc do.
405 unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
406 Align *= cast<VectorType>(Ty)->getNumElements();
407 // If the alignment is not a power of 2, round up to the next power of 2.
408 // This happens for non-power-of-2 length vectors.
409 if (Align & (Align-1))
410 Align = NextPowerOf2(Align);
415 // Since we got a "best match" index, just return it.
416 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
417 : Alignments[BestMatchIdx].PrefAlign;
422 class StructLayoutMap {
423 typedef DenseMap<StructType*, StructLayout*> LayoutInfoTy;
424 LayoutInfoTy LayoutInfo;
427 virtual ~StructLayoutMap() {
428 // Remove any layouts.
429 for (LayoutInfoTy::iterator I = LayoutInfo.begin(), E = LayoutInfo.end();
431 StructLayout *Value = I->second;
432 Value->~StructLayout();
437 StructLayout *&operator[](StructType *STy) {
438 return LayoutInfo[STy];
442 virtual void dump() const {}
445 } // end anonymous namespace
447 DataLayout::~DataLayout() {
448 delete static_cast<StructLayoutMap*>(LayoutMap);
451 const StructLayout *DataLayout::getStructLayout(StructType *Ty) const {
453 LayoutMap = new StructLayoutMap();
455 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
456 StructLayout *&SL = (*STM)[Ty];
459 // Otherwise, create the struct layout. Because it is variable length, we
460 // malloc it, then use placement new.
461 int NumElts = Ty->getNumElements();
463 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
465 // Set SL before calling StructLayout's ctor. The ctor could cause other
466 // entries to be added to TheMap, invalidating our reference.
469 new (L) StructLayout(Ty, *this);
474 std::string DataLayout::getStringRepresentation() const {
476 raw_string_ostream OS(Result);
478 OS << (LittleEndian ? "e" : "E");
479 SmallVector<unsigned, 8> addrSpaces;
480 // Lets get all of the known address spaces and sort them
481 // into increasing order so that we can emit the string
482 // in a cleaner format.
483 for (DenseMap<unsigned, PointerAlignElem>::const_iterator
484 pib = Pointers.begin(), pie = Pointers.end();
486 addrSpaces.push_back(pib->first);
488 std::sort(addrSpaces.begin(), addrSpaces.end());
489 for (SmallVector<unsigned, 8>::iterator asb = addrSpaces.begin(),
490 ase = addrSpaces.end(); asb != ase; ++asb) {
491 const PointerAlignElem &PI = Pointers.find(*asb)->second;
493 if (PI.AddressSpace) {
494 OS << PI.AddressSpace;
496 OS << ":" << PI.TypeBitWidth*8 << ':' << PI.ABIAlign*8
497 << ':' << PI.PrefAlign*8;
499 OS << "-S" << StackNaturalAlign*8;
501 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
502 const LayoutAlignElem &AI = Alignments[i];
503 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
504 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
507 if (!LegalIntWidths.empty()) {
508 OS << "-n" << (unsigned)LegalIntWidths[0];
510 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
511 OS << ':' << (unsigned)LegalIntWidths[i];
517 uint64_t DataLayout::getTypeSizeInBits(Type *Ty) const {
518 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
519 switch (Ty->getTypeID()) {
520 case Type::LabelTyID:
521 return getPointerSizeInBits(0);
522 case Type::PointerTyID: {
523 unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
524 return getPointerSizeInBits(AS);
526 case Type::ArrayTyID: {
527 ArrayType *ATy = cast<ArrayType>(Ty);
528 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
530 case Type::StructTyID:
531 // Get the layout annotation... which is lazily created on demand.
532 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
533 case Type::IntegerTyID:
534 return cast<IntegerType>(Ty)->getBitWidth();
537 case Type::FloatTyID:
539 case Type::DoubleTyID:
540 case Type::X86_MMXTyID:
542 case Type::PPC_FP128TyID:
543 case Type::FP128TyID:
545 // In memory objects this is always aligned to a higher boundary, but
546 // only 80 bits contain information.
547 case Type::X86_FP80TyID:
549 case Type::VectorTyID: {
550 VectorType *VTy = cast<VectorType>(Ty);
551 return VTy->getNumElements()*getTypeSizeInBits(VTy->getElementType());
554 llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
559 \param abi_or_pref Flag that determines which alignment is returned. true
560 returns the ABI alignment, false returns the preferred alignment.
561 \param Ty The underlying type for which alignment is determined.
563 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
564 == false) for the requested type \a Ty.
566 unsigned DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
569 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
570 switch (Ty->getTypeID()) {
571 // Early escape for the non-numeric types.
572 case Type::LabelTyID:
574 ? getPointerABIAlignment(0)
575 : getPointerPrefAlignment(0));
576 case Type::PointerTyID: {
577 unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
579 ? getPointerABIAlignment(AS)
580 : getPointerPrefAlignment(AS));
582 case Type::ArrayTyID:
583 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
585 case Type::StructTyID: {
586 // Packed structure types always have an ABI alignment of one.
587 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
590 // Get the layout annotation... which is lazily created on demand.
591 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
592 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
593 return std::max(Align, Layout->getAlignment());
595 case Type::IntegerTyID:
596 AlignType = INTEGER_ALIGN;
599 case Type::FloatTyID:
600 case Type::DoubleTyID:
601 // PPC_FP128TyID and FP128TyID have different data contents, but the
602 // same size and alignment, so they look the same here.
603 case Type::PPC_FP128TyID:
604 case Type::FP128TyID:
605 case Type::X86_FP80TyID:
606 AlignType = FLOAT_ALIGN;
608 case Type::X86_MMXTyID:
609 case Type::VectorTyID:
610 AlignType = VECTOR_ALIGN;
613 llvm_unreachable("Bad type for getAlignment!!!");
616 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
620 unsigned DataLayout::getABITypeAlignment(Type *Ty) const {
621 return getAlignment(Ty, true);
624 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
625 /// an integer type of the specified bitwidth.
626 unsigned DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
627 return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, 0);
631 unsigned DataLayout::getCallFrameTypeAlignment(Type *Ty) const {
632 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
633 if (Alignments[i].AlignType == STACK_ALIGN)
634 return Alignments[i].ABIAlign;
636 return getABITypeAlignment(Ty);
639 unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
640 return getAlignment(Ty, false);
643 unsigned DataLayout::getPreferredTypeAlignmentShift(Type *Ty) const {
644 unsigned Align = getPrefTypeAlignment(Ty);
645 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
646 return Log2_32(Align);
649 /// getIntPtrType - Return an integer type with size at least as big as that
650 /// of a pointer in the given address space.
651 IntegerType *DataLayout::getIntPtrType(LLVMContext &C,
652 unsigned AddressSpace) const {
653 return IntegerType::get(C, getPointerSizeInBits(AddressSpace));
656 /// getIntPtrType - Return an integer (vector of integer) type with size at
657 /// least as big as that of a pointer of the given pointer (vector of pointer)
659 Type *DataLayout::getIntPtrType(Type *Ty) const {
660 assert(Ty->isPtrOrPtrVectorTy() &&
661 "Expected a pointer or pointer vector type.");
662 unsigned NumBits = getTypeSizeInBits(Ty->getScalarType());
663 IntegerType *IntTy = IntegerType::get(Ty->getContext(), NumBits);
664 if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
665 return VectorType::get(IntTy, VecTy->getNumElements());
669 uint64_t DataLayout::getIndexedOffset(Type *ptrTy,
670 ArrayRef<Value *> Indices) const {
672 assert(Ty->isPointerTy() && "Illegal argument for getIndexedOffset()");
675 generic_gep_type_iterator<Value* const*>
676 TI = gep_type_begin(ptrTy, Indices);
677 for (unsigned CurIDX = 0, EndIDX = Indices.size(); CurIDX != EndIDX;
679 if (StructType *STy = dyn_cast<StructType>(*TI)) {
680 assert(Indices[CurIDX]->getType() ==
681 Type::getInt32Ty(ptrTy->getContext()) &&
682 "Illegal struct idx");
683 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
685 // Get structure layout information...
686 const StructLayout *Layout = getStructLayout(STy);
688 // Add in the offset, as calculated by the structure layout info...
689 Result += Layout->getElementOffset(FieldNo);
691 // Update Ty to refer to current element
692 Ty = STy->getElementType(FieldNo);
694 // Update Ty to refer to current element
695 Ty = cast<SequentialType>(Ty)->getElementType();
697 // Get the array index and the size of each array element.
698 if (int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue())
699 Result += (uint64_t)arrayIdx * getTypeAllocSize(Ty);
706 /// getPreferredAlignment - Return the preferred alignment of the specified
707 /// global. This includes an explicitly requested alignment (if the global
709 unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
710 Type *ElemType = GV->getType()->getElementType();
711 unsigned Alignment = getPrefTypeAlignment(ElemType);
712 unsigned GVAlignment = GV->getAlignment();
713 if (GVAlignment >= Alignment) {
714 Alignment = GVAlignment;
715 } else if (GVAlignment != 0) {
716 Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType));
719 if (GV->hasInitializer() && GVAlignment == 0) {
720 if (Alignment < 16) {
721 // If the global is not external, see if it is large. If so, give it a
723 if (getTypeSizeInBits(ElemType) > 128)
724 Alignment = 16; // 16-byte alignment.
730 /// getPreferredAlignmentLog - Return the preferred alignment of the
731 /// specified global, returned in log form. This includes an explicitly
732 /// requested alignment (if the global has one).
733 unsigned DataLayout::getPreferredAlignmentLog(const GlobalVariable *GV) const {
734 return Log2_32(getPreferredAlignment(GV));