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 /// getInt - Get an integer ignoring errors.
156 static int getInt(StringRef R) {
158 R.getAsInteger(10, Result);
162 void DataLayout::init() {
163 initializeDataLayoutPass(*PassRegistry::getPassRegistry());
166 LittleEndian = false;
167 StackNaturalAlign = 0;
169 // Default alignments
170 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
171 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
172 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
173 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
174 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
175 setAlignment(FLOAT_ALIGN, 2, 2, 16); // half
176 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
177 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
178 setAlignment(FLOAT_ALIGN, 16, 16, 128); // ppcf128, quad, ...
179 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32, v1i64, ...
180 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
181 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct
182 setPointerAlignment(0, 8, 8, 8);
185 std::string DataLayout::parseSpecifier(StringRef Desc, DataLayout *td) {
190 while (!Desc.empty()) {
191 std::pair<StringRef, StringRef> Split = Desc.split('-');
192 StringRef Token = Split.first;
198 Split = Token.split(':');
199 StringRef Specifier = Split.first;
200 Token = Split.second;
202 assert(!Specifier.empty() && "Can't be empty here");
204 switch (Specifier[0]) {
207 td->LittleEndian = false;
211 td->LittleEndian = true;
215 if (Specifier.size() > 1) {
216 AddrSpace = getInt(Specifier.substr(1));
217 if (AddrSpace < 0 || AddrSpace > (1 << 24))
218 return "Invalid address space, must be a positive 24bit integer";
220 Split = Token.split(':');
221 int PointerMemSizeBits = getInt(Split.first);
222 if (PointerMemSizeBits < 0 || PointerMemSizeBits % 8 != 0)
223 return "invalid pointer size, must be a positive 8-bit multiple";
225 // Pointer ABI alignment.
226 Split = Split.second.split(':');
227 int PointerABIAlignBits = getInt(Split.first);
228 if (PointerABIAlignBits < 0 || PointerABIAlignBits % 8 != 0) {
229 return "invalid pointer ABI alignment, "
230 "must be a positive 8-bit multiple";
233 // Pointer preferred alignment.
234 Split = Split.second.split(':');
235 int PointerPrefAlignBits = getInt(Split.first);
236 if (PointerPrefAlignBits < 0 || PointerPrefAlignBits % 8 != 0) {
237 return "invalid pointer preferred alignment, "
238 "must be a positive 8-bit multiple";
241 if (PointerPrefAlignBits == 0)
242 PointerPrefAlignBits = PointerABIAlignBits;
244 td->setPointerAlignment(AddrSpace, PointerABIAlignBits/8,
245 PointerPrefAlignBits/8, PointerMemSizeBits/8);
253 AlignTypeEnum AlignType;
254 char field = Specifier[0];
257 case 'i': AlignType = INTEGER_ALIGN; break;
258 case 'v': AlignType = VECTOR_ALIGN; break;
259 case 'f': AlignType = FLOAT_ALIGN; break;
260 case 'a': AlignType = AGGREGATE_ALIGN; break;
261 case 's': AlignType = STACK_ALIGN; break;
263 int Size = getInt(Specifier.substr(1));
265 return std::string("invalid ") + field + "-size field, "
269 Split = Token.split(':');
270 int ABIAlignBits = getInt(Split.first);
271 if (ABIAlignBits < 0 || ABIAlignBits % 8 != 0) {
272 return std::string("invalid ") + field +"-abi-alignment field, "
273 "must be a positive 8-bit multiple";
275 unsigned ABIAlign = ABIAlignBits / 8;
277 Split = Split.second.split(':');
279 int PrefAlignBits = getInt(Split.first);
280 if (PrefAlignBits < 0 || PrefAlignBits % 8 != 0) {
281 return std::string("invalid ") + field +"-preferred-alignment field, "
282 "must be a positive 8-bit multiple";
284 unsigned PrefAlign = PrefAlignBits / 8;
286 PrefAlign = ABIAlign;
289 td->setAlignment(AlignType, ABIAlign, PrefAlign, Size);
292 case 'n': // Native integer types.
293 Specifier = Specifier.substr(1);
295 int Width = getInt(Specifier);
297 return std::string("invalid native integer size \'") +
298 Specifier.str() + "\', must be a positive integer.";
300 if (td && Width != 0)
301 td->LegalIntWidths.push_back(Width);
302 Split = Token.split(':');
303 Specifier = Split.first;
304 Token = Split.second;
305 } while (!Specifier.empty() || !Token.empty());
307 case 'S': { // Stack natural alignment.
308 int StackNaturalAlignBits = getInt(Specifier.substr(1));
309 if (StackNaturalAlignBits < 0 || StackNaturalAlignBits % 8 != 0) {
310 return "invalid natural stack alignment (S-field), "
311 "must be a positive 8-bit multiple";
314 td->StackNaturalAlign = StackNaturalAlignBits / 8;
327 /// @note This has to exist, because this is a pass, but it should never be
329 DataLayout::DataLayout() : ImmutablePass(ID) {
330 report_fatal_error("Bad DataLayout ctor used. "
331 "Tool did not specify a DataLayout to use?");
334 DataLayout::DataLayout(const Module *M)
335 : ImmutablePass(ID) {
336 std::string errMsg = parseSpecifier(M->getDataLayout(), this);
337 assert(errMsg == "" && "Module M has malformed data layout string.");
342 DataLayout::setAlignment(AlignTypeEnum align_type, unsigned abi_align,
343 unsigned pref_align, uint32_t bit_width) {
344 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
345 assert(pref_align < (1 << 16) && "Alignment doesn't fit in bitfield");
346 assert(bit_width < (1 << 24) && "Bit width doesn't fit in bitfield");
347 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
348 if (Alignments[i].AlignType == (unsigned)align_type &&
349 Alignments[i].TypeBitWidth == bit_width) {
350 // Update the abi, preferred alignments.
351 Alignments[i].ABIAlign = abi_align;
352 Alignments[i].PrefAlign = pref_align;
357 Alignments.push_back(LayoutAlignElem::get(align_type, abi_align,
358 pref_align, bit_width));
362 DataLayout::setPointerAlignment(uint32_t addr_space, unsigned abi_align,
363 unsigned pref_align, uint32_t bit_width) {
364 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
365 DenseMap<unsigned,PointerAlignElem>::iterator val = Pointers.find(addr_space);
366 if (val == Pointers.end()) {
367 Pointers[addr_space] = PointerAlignElem::get(addr_space,
368 abi_align, pref_align, bit_width);
370 val->second.ABIAlign = abi_align;
371 val->second.PrefAlign = pref_align;
372 val->second.TypeBitWidth = bit_width;
376 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
377 /// preferred if ABIInfo = false) the layout wants for the specified datatype.
378 unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
379 uint32_t BitWidth, bool ABIInfo,
381 // Check to see if we have an exact match and remember the best match we see.
382 int BestMatchIdx = -1;
384 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
385 if (Alignments[i].AlignType == (unsigned)AlignType &&
386 Alignments[i].TypeBitWidth == BitWidth)
387 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
389 // The best match so far depends on what we're looking for.
390 if (AlignType == INTEGER_ALIGN &&
391 Alignments[i].AlignType == INTEGER_ALIGN) {
392 // The "best match" for integers is the smallest size that is larger than
393 // the BitWidth requested.
394 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
395 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
397 // However, if there isn't one that's larger, then we must use the
398 // largest one we have (see below)
399 if (LargestInt == -1 ||
400 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
405 // Okay, we didn't find an exact solution. Fall back here depending on what
406 // is being looked for.
407 if (BestMatchIdx == -1) {
408 // If we didn't find an integer alignment, fall back on most conservative.
409 if (AlignType == INTEGER_ALIGN) {
410 BestMatchIdx = LargestInt;
412 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
414 // By default, use natural alignment for vector types. This is consistent
415 // with what clang and llvm-gcc do.
416 unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
417 Align *= cast<VectorType>(Ty)->getNumElements();
418 // If the alignment is not a power of 2, round up to the next power of 2.
419 // This happens for non-power-of-2 length vectors.
420 if (Align & (Align-1))
421 Align = NextPowerOf2(Align);
426 // Since we got a "best match" index, just return it.
427 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
428 : Alignments[BestMatchIdx].PrefAlign;
433 class StructLayoutMap {
434 typedef DenseMap<StructType*, StructLayout*> LayoutInfoTy;
435 LayoutInfoTy LayoutInfo;
438 virtual ~StructLayoutMap() {
439 // Remove any layouts.
440 for (LayoutInfoTy::iterator I = LayoutInfo.begin(), E = LayoutInfo.end();
442 StructLayout *Value = I->second;
443 Value->~StructLayout();
448 StructLayout *&operator[](StructType *STy) {
449 return LayoutInfo[STy];
453 virtual void dump() const {}
456 } // end anonymous namespace
458 DataLayout::~DataLayout() {
459 delete static_cast<StructLayoutMap*>(LayoutMap);
462 const StructLayout *DataLayout::getStructLayout(StructType *Ty) const {
464 LayoutMap = new StructLayoutMap();
466 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
467 StructLayout *&SL = (*STM)[Ty];
470 // Otherwise, create the struct layout. Because it is variable length, we
471 // malloc it, then use placement new.
472 int NumElts = Ty->getNumElements();
474 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
476 // Set SL before calling StructLayout's ctor. The ctor could cause other
477 // entries to be added to TheMap, invalidating our reference.
480 new (L) StructLayout(Ty, *this);
485 std::string DataLayout::getStringRepresentation() const {
487 raw_string_ostream OS(Result);
489 OS << (LittleEndian ? "e" : "E");
490 SmallVector<unsigned, 8> addrSpaces;
491 // Lets get all of the known address spaces and sort them
492 // into increasing order so that we can emit the string
493 // in a cleaner format.
494 for (DenseMap<unsigned, PointerAlignElem>::const_iterator
495 pib = Pointers.begin(), pie = Pointers.end();
497 addrSpaces.push_back(pib->first);
499 std::sort(addrSpaces.begin(), addrSpaces.end());
500 for (SmallVector<unsigned, 8>::iterator asb = addrSpaces.begin(),
501 ase = addrSpaces.end(); asb != ase; ++asb) {
502 const PointerAlignElem &PI = Pointers.find(*asb)->second;
504 if (PI.AddressSpace) {
505 OS << PI.AddressSpace;
507 OS << ":" << PI.TypeBitWidth*8 << ':' << PI.ABIAlign*8
508 << ':' << PI.PrefAlign*8;
510 OS << "-S" << StackNaturalAlign*8;
512 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
513 const LayoutAlignElem &AI = Alignments[i];
514 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
515 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
518 if (!LegalIntWidths.empty()) {
519 OS << "-n" << (unsigned)LegalIntWidths[0];
521 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
522 OS << ':' << (unsigned)LegalIntWidths[i];
528 uint64_t DataLayout::getTypeSizeInBits(Type *Ty) const {
529 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
530 switch (Ty->getTypeID()) {
531 case Type::LabelTyID:
532 return getPointerSizeInBits(0);
533 case Type::PointerTyID: {
534 unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
535 return getPointerSizeInBits(AS);
537 case Type::ArrayTyID: {
538 ArrayType *ATy = cast<ArrayType>(Ty);
539 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
541 case Type::StructTyID:
542 // Get the layout annotation... which is lazily created on demand.
543 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
544 case Type::IntegerTyID:
545 return cast<IntegerType>(Ty)->getBitWidth();
550 case Type::FloatTyID:
552 case Type::DoubleTyID:
553 case Type::X86_MMXTyID:
555 case Type::PPC_FP128TyID:
556 case Type::FP128TyID:
558 // In memory objects this is always aligned to a higher boundary, but
559 // only 80 bits contain information.
560 case Type::X86_FP80TyID:
562 case Type::VectorTyID:
563 return cast<VectorType>(Ty)->getBitWidth();
565 llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
570 \param abi_or_pref Flag that determines which alignment is returned. true
571 returns the ABI alignment, false returns the preferred alignment.
572 \param Ty The underlying type for which alignment is determined.
574 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
575 == false) for the requested type \a Ty.
577 unsigned DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
580 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
581 switch (Ty->getTypeID()) {
582 // Early escape for the non-numeric types.
583 case Type::LabelTyID:
585 ? getPointerABIAlignment(0)
586 : getPointerPrefAlignment(0));
587 case Type::PointerTyID: {
588 unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
590 ? getPointerABIAlignment(AS)
591 : getPointerPrefAlignment(AS));
593 case Type::ArrayTyID:
594 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
596 case Type::StructTyID: {
597 // Packed structure types always have an ABI alignment of one.
598 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
601 // Get the layout annotation... which is lazily created on demand.
602 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
603 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
604 return std::max(Align, Layout->getAlignment());
606 case Type::IntegerTyID:
608 AlignType = INTEGER_ALIGN;
611 case Type::FloatTyID:
612 case Type::DoubleTyID:
613 // PPC_FP128TyID and FP128TyID have different data contents, but the
614 // same size and alignment, so they look the same here.
615 case Type::PPC_FP128TyID:
616 case Type::FP128TyID:
617 case Type::X86_FP80TyID:
618 AlignType = FLOAT_ALIGN;
620 case Type::X86_MMXTyID:
621 case Type::VectorTyID:
622 AlignType = VECTOR_ALIGN;
625 llvm_unreachable("Bad type for getAlignment!!!");
628 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
632 unsigned DataLayout::getABITypeAlignment(Type *Ty) const {
633 return getAlignment(Ty, true);
636 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
637 /// an integer type of the specified bitwidth.
638 unsigned DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
639 return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, 0);
643 unsigned DataLayout::getCallFrameTypeAlignment(Type *Ty) const {
644 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
645 if (Alignments[i].AlignType == STACK_ALIGN)
646 return Alignments[i].ABIAlign;
648 return getABITypeAlignment(Ty);
651 unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
652 return getAlignment(Ty, false);
655 unsigned DataLayout::getPreferredTypeAlignmentShift(Type *Ty) const {
656 unsigned Align = getPrefTypeAlignment(Ty);
657 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
658 return Log2_32(Align);
661 /// getIntPtrType - Return an unsigned integer type that is the same size or
662 /// greater to the host pointer size.
663 IntegerType *DataLayout::getIntPtrType(LLVMContext &C,
664 unsigned AddressSpace) const {
665 return IntegerType::get(C, getPointerSizeInBits(AddressSpace));
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));