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/IR/DataLayout.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/IR/Constants.h"
24 #include "llvm/IR/DerivedTypes.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/GetElementPtrTypeIterator.h"
28 #include "llvm/Support/ManagedStatic.h"
29 #include "llvm/Support/MathExtras.h"
30 #include "llvm/Support/Mutex.h"
31 #include "llvm/Support/raw_ostream.h"
36 // Handle the Pass registration stuff necessary to use DataLayout's.
38 // Register the default SparcV9 implementation...
39 INITIALIZE_PASS(DataLayout, "datalayout", "Data Layout", false, true)
40 char DataLayout::ID = 0;
42 //===----------------------------------------------------------------------===//
43 // Support for StructLayout
44 //===----------------------------------------------------------------------===//
46 StructLayout::StructLayout(StructType *ST, const DataLayout &DL) {
47 assert(!ST->isOpaque() && "Cannot get layout of opaque structs");
50 NumElements = ST->getNumElements();
52 // Loop over each of the elements, placing them in memory.
53 for (unsigned i = 0, e = NumElements; i != e; ++i) {
54 Type *Ty = ST->getElementType(i);
55 unsigned TyAlign = ST->isPacked() ? 1 : DL.getABITypeAlignment(Ty);
57 // Add padding if necessary to align the data element properly.
58 if ((StructSize & (TyAlign-1)) != 0)
59 StructSize = DataLayout::RoundUpAlignment(StructSize, TyAlign);
61 // Keep track of maximum alignment constraint.
62 StructAlignment = std::max(TyAlign, StructAlignment);
64 MemberOffsets[i] = StructSize;
65 StructSize += DL.getTypeAllocSize(Ty); // Consume space for this data item
68 // Empty structures have alignment of 1 byte.
69 if (StructAlignment == 0) StructAlignment = 1;
71 // Add padding to the end of the struct so that it could be put in an array
72 // and all array elements would be aligned correctly.
73 if ((StructSize & (StructAlignment-1)) != 0)
74 StructSize = DataLayout::RoundUpAlignment(StructSize, StructAlignment);
78 /// getElementContainingOffset - Given a valid offset into the structure,
79 /// return the structure index that contains it.
80 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
82 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
83 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
85 assert(*SI <= Offset && "upper_bound didn't work");
86 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
87 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
88 "Upper bound didn't work!");
90 // Multiple fields can have the same offset if any of them are zero sized.
91 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
92 // at the i32 element, because it is the last element at that offset. This is
93 // the right one to return, because anything after it will have a higher
94 // offset, implying that this element is non-empty.
95 return SI-&MemberOffsets[0];
98 //===----------------------------------------------------------------------===//
99 // LayoutAlignElem, LayoutAlign support
100 //===----------------------------------------------------------------------===//
103 LayoutAlignElem::get(AlignTypeEnum align_type, unsigned abi_align,
104 unsigned pref_align, uint32_t bit_width) {
105 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
106 LayoutAlignElem retval;
107 retval.AlignType = align_type;
108 retval.ABIAlign = abi_align;
109 retval.PrefAlign = pref_align;
110 retval.TypeBitWidth = bit_width;
115 LayoutAlignElem::operator==(const LayoutAlignElem &rhs) const {
116 return (AlignType == rhs.AlignType
117 && ABIAlign == rhs.ABIAlign
118 && PrefAlign == rhs.PrefAlign
119 && TypeBitWidth == rhs.TypeBitWidth);
122 const LayoutAlignElem
123 DataLayout::InvalidAlignmentElem = { INVALID_ALIGN, 0, 0, 0 };
125 //===----------------------------------------------------------------------===//
126 // PointerAlignElem, PointerAlign support
127 //===----------------------------------------------------------------------===//
130 PointerAlignElem::get(uint32_t AddressSpace, unsigned ABIAlign,
131 unsigned PrefAlign, uint32_t TypeByteWidth) {
132 assert(ABIAlign <= PrefAlign && "Preferred alignment worse than ABI!");
133 PointerAlignElem retval;
134 retval.AddressSpace = AddressSpace;
135 retval.ABIAlign = ABIAlign;
136 retval.PrefAlign = PrefAlign;
137 retval.TypeByteWidth = TypeByteWidth;
142 PointerAlignElem::operator==(const PointerAlignElem &rhs) const {
143 return (ABIAlign == rhs.ABIAlign
144 && AddressSpace == rhs.AddressSpace
145 && PrefAlign == rhs.PrefAlign
146 && TypeByteWidth == rhs.TypeByteWidth);
149 const PointerAlignElem
150 DataLayout::InvalidPointerElem = { 0U, 0U, 0U, ~0U };
152 //===----------------------------------------------------------------------===//
153 // DataLayout Class Implementation
154 //===----------------------------------------------------------------------===//
156 const char *DataLayout::getManglingComponent(const Triple &T) {
157 if (T.isOSBinFormatMachO())
159 if (T.isOSBinFormatELF() || T.isArch64Bit())
161 assert(T.isOSBinFormatCOFF());
165 static const LayoutAlignElem DefaultAlignments[] = {
166 { INTEGER_ALIGN, 1, 1, 1 }, // i1
167 { INTEGER_ALIGN, 8, 1, 1 }, // i8
168 { INTEGER_ALIGN, 16, 2, 2 }, // i16
169 { INTEGER_ALIGN, 32, 4, 4 }, // i32
170 { INTEGER_ALIGN, 64, 4, 8 }, // i64
171 { FLOAT_ALIGN, 16, 2, 2 }, // half
172 { FLOAT_ALIGN, 32, 4, 4 }, // float
173 { FLOAT_ALIGN, 64, 8, 8 }, // double
174 { FLOAT_ALIGN, 128, 16, 16 }, // ppcf128, quad, ...
175 { VECTOR_ALIGN, 64, 8, 8 }, // v2i32, v1i64, ...
176 { VECTOR_ALIGN, 128, 16, 16 }, // v16i8, v8i16, v4i32, ...
177 { AGGREGATE_ALIGN, 0, 0, 8 } // struct
180 void DataLayout::init(StringRef Desc) {
181 initializeDataLayoutPass(*PassRegistry::getPassRegistry());
184 LittleEndian = false;
185 StackNaturalAlign = 0;
186 ManglingMode = MM_None;
188 // Default alignments
189 for (int I = 0, N = array_lengthof(DefaultAlignments); I < N; ++I) {
190 const LayoutAlignElem &E = DefaultAlignments[I];
191 setAlignment((AlignTypeEnum)E.AlignType, E.ABIAlign, E.PrefAlign,
194 setPointerAlignment(0, 8, 8, 8);
196 parseSpecifier(Desc);
199 /// Checked version of split, to ensure mandatory subparts.
200 static std::pair<StringRef, StringRef> split(StringRef Str, char Separator) {
201 assert(!Str.empty() && "parse error, string can't be empty here");
202 std::pair<StringRef, StringRef> Split = Str.split(Separator);
203 assert((!Split.second.empty() || Split.first == Str) &&
204 "a trailing separator is not allowed");
208 /// Get an unsinged integer, including error checks.
209 static unsigned getInt(StringRef R) {
211 bool error = R.getAsInteger(10, Result); (void)error;
212 assert(!error && "not a number, or does not fit in an unsigned int");
216 /// Convert bits into bytes. Assert if not a byte width multiple.
217 static unsigned inBytes(unsigned Bits) {
218 assert(Bits % 8 == 0 && "number of bits must be a byte width multiple");
222 void DataLayout::parseSpecifier(StringRef Desc) {
223 while (!Desc.empty()) {
225 std::pair<StringRef, StringRef> Split = split(Desc, '-');
229 Split = split(Split.first, ':');
231 // Aliases used below.
232 StringRef &Tok = Split.first; // Current token.
233 StringRef &Rest = Split.second; // The rest of the string.
235 char Specifier = Tok.front();
240 // Ignored for backward compatibility.
241 // FIXME: remove this on LLVM 4.0.
244 LittleEndian = false;
251 unsigned AddrSpace = Tok.empty() ? 0 : getInt(Tok);
252 assert(AddrSpace < 1 << 24 &&
253 "Invalid address space, must be a 24bit integer");
256 Split = split(Rest, ':');
257 unsigned PointerMemSize = inBytes(getInt(Tok));
260 Split = split(Rest, ':');
261 unsigned PointerABIAlign = inBytes(getInt(Tok));
263 // Preferred alignment.
264 unsigned PointerPrefAlign = PointerABIAlign;
266 Split = split(Rest, ':');
267 PointerPrefAlign = inBytes(getInt(Tok));
270 setPointerAlignment(AddrSpace, PointerABIAlign, PointerPrefAlign,
278 AlignTypeEnum AlignType;
281 case 'i': AlignType = INTEGER_ALIGN; break;
282 case 'v': AlignType = VECTOR_ALIGN; break;
283 case 'f': AlignType = FLOAT_ALIGN; break;
284 case 'a': AlignType = AGGREGATE_ALIGN; break;
288 unsigned Size = Tok.empty() ? 0 : getInt(Tok);
291 Split = split(Rest, ':');
292 unsigned ABIAlign = inBytes(getInt(Tok));
294 // Preferred alignment.
295 unsigned PrefAlign = ABIAlign;
297 Split = split(Rest, ':');
298 PrefAlign = inBytes(getInt(Tok));
301 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
305 case 'n': // Native integer types.
307 unsigned Width = getInt(Tok);
308 assert(Width != 0 && "width must be non-zero");
309 LegalIntWidths.push_back(Width);
312 Split = split(Rest, ':');
315 case 'S': { // Stack natural alignment.
316 StackNaturalAlign = inBytes(getInt(Tok));
321 assert(Rest.size() == 1);
324 llvm_unreachable("Unknown mangling in datalayout string");
326 ManglingMode = MM_ELF;
329 ManglingMode = MM_MachO;
332 ManglingMode = MM_Mips;
335 ManglingMode = MM_COFF;
340 llvm_unreachable("Unknown specifier in datalayout string");
348 /// @note This has to exist, because this is a pass, but it should never be
350 DataLayout::DataLayout() : ImmutablePass(ID) {
351 report_fatal_error("Bad DataLayout ctor used. "
352 "Tool did not specify a DataLayout to use?");
355 DataLayout::DataLayout(const Module *M)
356 : ImmutablePass(ID) {
357 init(M->getDataLayout());
361 DataLayout::setAlignment(AlignTypeEnum align_type, unsigned abi_align,
362 unsigned pref_align, uint32_t bit_width) {
363 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
364 assert(pref_align < (1 << 16) && "Alignment doesn't fit in bitfield");
365 assert(bit_width < (1 << 24) && "Bit width doesn't fit in bitfield");
366 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
367 if (Alignments[i].AlignType == (unsigned)align_type &&
368 Alignments[i].TypeBitWidth == bit_width) {
369 // Update the abi, preferred alignments.
370 Alignments[i].ABIAlign = abi_align;
371 Alignments[i].PrefAlign = pref_align;
376 Alignments.push_back(LayoutAlignElem::get(align_type, abi_align,
377 pref_align, bit_width));
380 void DataLayout::setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign,
382 uint32_t TypeByteWidth) {
383 assert(ABIAlign <= PrefAlign && "Preferred alignment worse than ABI!");
384 DenseMap<unsigned,PointerAlignElem>::iterator val = Pointers.find(AddrSpace);
385 if (val == Pointers.end()) {
386 Pointers[AddrSpace] =
387 PointerAlignElem::get(AddrSpace, ABIAlign, PrefAlign, TypeByteWidth);
389 val->second.ABIAlign = ABIAlign;
390 val->second.PrefAlign = PrefAlign;
391 val->second.TypeByteWidth = TypeByteWidth;
395 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
396 /// preferred if ABIInfo = false) the layout wants for the specified datatype.
397 unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
398 uint32_t BitWidth, bool ABIInfo,
400 // Check to see if we have an exact match and remember the best match we see.
401 int BestMatchIdx = -1;
403 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
404 if (Alignments[i].AlignType == (unsigned)AlignType &&
405 Alignments[i].TypeBitWidth == BitWidth)
406 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
408 // The best match so far depends on what we're looking for.
409 if (AlignType == INTEGER_ALIGN &&
410 Alignments[i].AlignType == INTEGER_ALIGN) {
411 // The "best match" for integers is the smallest size that is larger than
412 // the BitWidth requested.
413 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
414 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
416 // However, if there isn't one that's larger, then we must use the
417 // largest one we have (see below)
418 if (LargestInt == -1 ||
419 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
424 // Okay, we didn't find an exact solution. Fall back here depending on what
425 // is being looked for.
426 if (BestMatchIdx == -1) {
427 // If we didn't find an integer alignment, fall back on most conservative.
428 if (AlignType == INTEGER_ALIGN) {
429 BestMatchIdx = LargestInt;
431 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
433 // By default, use natural alignment for vector types. This is consistent
434 // with what clang and llvm-gcc do.
435 unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
436 Align *= cast<VectorType>(Ty)->getNumElements();
437 // If the alignment is not a power of 2, round up to the next power of 2.
438 // This happens for non-power-of-2 length vectors.
439 if (Align & (Align-1))
440 Align = NextPowerOf2(Align);
445 // Since we got a "best match" index, just return it.
446 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
447 : Alignments[BestMatchIdx].PrefAlign;
452 class StructLayoutMap {
453 typedef DenseMap<StructType*, StructLayout*> LayoutInfoTy;
454 LayoutInfoTy LayoutInfo;
457 virtual ~StructLayoutMap() {
458 // Remove any layouts.
459 for (LayoutInfoTy::iterator I = LayoutInfo.begin(), E = LayoutInfo.end();
461 StructLayout *Value = I->second;
462 Value->~StructLayout();
467 StructLayout *&operator[](StructType *STy) {
468 return LayoutInfo[STy];
472 virtual void dump() const {}
475 } // end anonymous namespace
477 DataLayout::~DataLayout() {
478 delete static_cast<StructLayoutMap*>(LayoutMap);
481 bool DataLayout::doFinalization(Module &M) {
482 delete static_cast<StructLayoutMap*>(LayoutMap);
487 const StructLayout *DataLayout::getStructLayout(StructType *Ty) const {
489 LayoutMap = new StructLayoutMap();
491 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
492 StructLayout *&SL = (*STM)[Ty];
495 // Otherwise, create the struct layout. Because it is variable length, we
496 // malloc it, then use placement new.
497 int NumElts = Ty->getNumElements();
499 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
501 // Set SL before calling StructLayout's ctor. The ctor could cause other
502 // entries to be added to TheMap, invalidating our reference.
505 new (L) StructLayout(Ty, *this);
510 std::string DataLayout::getStringRepresentation() const {
512 raw_string_ostream OS(Result);
514 OS << (LittleEndian ? "e" : "E");
516 switch (ManglingMode) {
533 SmallVector<unsigned, 8> addrSpaces;
534 // Lets get all of the known address spaces and sort them
535 // into increasing order so that we can emit the string
536 // in a cleaner format.
537 for (DenseMap<unsigned, PointerAlignElem>::const_iterator
538 pib = Pointers.begin(), pie = Pointers.end();
540 addrSpaces.push_back(pib->first);
542 std::sort(addrSpaces.begin(), addrSpaces.end());
543 for (SmallVectorImpl<unsigned>::iterator asb = addrSpaces.begin(),
544 ase = addrSpaces.end(); asb != ase; ++asb) {
545 const PointerAlignElem &PI = Pointers.find(*asb)->second;
548 if (PI.AddressSpace == 0 && PI.ABIAlign == 8 && PI.PrefAlign == 8 &&
549 PI.TypeByteWidth == 8)
553 if (PI.AddressSpace) {
554 OS << PI.AddressSpace;
556 OS << ":" << PI.TypeByteWidth*8 << ':' << PI.ABIAlign*8;
557 if (PI.PrefAlign != PI.ABIAlign)
558 OS << ':' << PI.PrefAlign*8;
561 const LayoutAlignElem *DefaultStart = DefaultAlignments;
562 const LayoutAlignElem *DefaultEnd =
563 DefaultStart + array_lengthof(DefaultAlignments);
564 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
565 const LayoutAlignElem &AI = Alignments[i];
566 if (std::find(DefaultStart, DefaultEnd, AI) != DefaultEnd)
568 OS << '-' << (char)AI.AlignType;
570 OS << AI.TypeBitWidth;
571 OS << ':' << AI.ABIAlign*8;
572 if (AI.ABIAlign != AI.PrefAlign)
573 OS << ':' << AI.PrefAlign*8;
576 if (!LegalIntWidths.empty()) {
577 OS << "-n" << (unsigned)LegalIntWidths[0];
579 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
580 OS << ':' << (unsigned)LegalIntWidths[i];
583 if (StackNaturalAlign)
584 OS << "-S" << StackNaturalAlign*8;
589 unsigned DataLayout::getPointerTypeSizeInBits(Type *Ty) const {
590 assert(Ty->isPtrOrPtrVectorTy() &&
591 "This should only be called with a pointer or pointer vector type");
593 if (Ty->isPointerTy())
594 return getTypeSizeInBits(Ty);
596 return getTypeSizeInBits(Ty->getScalarType());
600 \param abi_or_pref Flag that determines which alignment is returned. true
601 returns the ABI alignment, false returns the preferred alignment.
602 \param Ty The underlying type for which alignment is determined.
604 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
605 == false) for the requested type \a Ty.
607 unsigned DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
610 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
611 switch (Ty->getTypeID()) {
612 // Early escape for the non-numeric types.
613 case Type::LabelTyID:
615 ? getPointerABIAlignment(0)
616 : getPointerPrefAlignment(0));
617 case Type::PointerTyID: {
618 unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
620 ? getPointerABIAlignment(AS)
621 : getPointerPrefAlignment(AS));
623 case Type::ArrayTyID:
624 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
626 case Type::StructTyID: {
627 // Packed structure types always have an ABI alignment of one.
628 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
631 // Get the layout annotation... which is lazily created on demand.
632 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
633 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
634 return std::max(Align, Layout->getAlignment());
636 case Type::IntegerTyID:
637 AlignType = INTEGER_ALIGN;
640 case Type::FloatTyID:
641 case Type::DoubleTyID:
642 // PPC_FP128TyID and FP128TyID have different data contents, but the
643 // same size and alignment, so they look the same here.
644 case Type::PPC_FP128TyID:
645 case Type::FP128TyID:
646 case Type::X86_FP80TyID:
647 AlignType = FLOAT_ALIGN;
649 case Type::X86_MMXTyID:
650 case Type::VectorTyID:
651 AlignType = VECTOR_ALIGN;
654 llvm_unreachable("Bad type for getAlignment!!!");
657 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
661 unsigned DataLayout::getABITypeAlignment(Type *Ty) const {
662 return getAlignment(Ty, true);
665 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
666 /// an integer type of the specified bitwidth.
667 unsigned DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
668 return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, 0);
671 unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
672 return getAlignment(Ty, false);
675 unsigned DataLayout::getPreferredTypeAlignmentShift(Type *Ty) const {
676 unsigned Align = getPrefTypeAlignment(Ty);
677 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
678 return Log2_32(Align);
681 IntegerType *DataLayout::getIntPtrType(LLVMContext &C,
682 unsigned AddressSpace) const {
683 return IntegerType::get(C, getPointerSizeInBits(AddressSpace));
686 Type *DataLayout::getIntPtrType(Type *Ty) const {
687 assert(Ty->isPtrOrPtrVectorTy() &&
688 "Expected a pointer or pointer vector type.");
689 unsigned NumBits = getTypeSizeInBits(Ty->getScalarType());
690 IntegerType *IntTy = IntegerType::get(Ty->getContext(), NumBits);
691 if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
692 return VectorType::get(IntTy, VecTy->getNumElements());
696 Type *DataLayout::getSmallestLegalIntType(LLVMContext &C, unsigned Width) const {
697 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
698 if (Width <= LegalIntWidths[i])
699 return Type::getIntNTy(C, LegalIntWidths[i]);
703 unsigned DataLayout::getLargestLegalIntTypeSize() const {
704 unsigned MaxWidth = 0;
705 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
706 MaxWidth = std::max<unsigned>(MaxWidth, LegalIntWidths[i]);
710 uint64_t DataLayout::getIndexedOffset(Type *ptrTy,
711 ArrayRef<Value *> Indices) const {
713 assert(Ty->isPointerTy() && "Illegal argument for getIndexedOffset()");
716 generic_gep_type_iterator<Value* const*>
717 TI = gep_type_begin(ptrTy, Indices);
718 for (unsigned CurIDX = 0, EndIDX = Indices.size(); CurIDX != EndIDX;
720 if (StructType *STy = dyn_cast<StructType>(*TI)) {
721 assert(Indices[CurIDX]->getType() ==
722 Type::getInt32Ty(ptrTy->getContext()) &&
723 "Illegal struct idx");
724 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
726 // Get structure layout information...
727 const StructLayout *Layout = getStructLayout(STy);
729 // Add in the offset, as calculated by the structure layout info...
730 Result += Layout->getElementOffset(FieldNo);
732 // Update Ty to refer to current element
733 Ty = STy->getElementType(FieldNo);
735 // Update Ty to refer to current element
736 Ty = cast<SequentialType>(Ty)->getElementType();
738 // Get the array index and the size of each array element.
739 if (int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue())
740 Result += (uint64_t)arrayIdx * getTypeAllocSize(Ty);
747 /// getPreferredAlignment - Return the preferred alignment of the specified
748 /// global. This includes an explicitly requested alignment (if the global
750 unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
751 Type *ElemType = GV->getType()->getElementType();
752 unsigned Alignment = getPrefTypeAlignment(ElemType);
753 unsigned GVAlignment = GV->getAlignment();
754 if (GVAlignment >= Alignment) {
755 Alignment = GVAlignment;
756 } else if (GVAlignment != 0) {
757 Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType));
760 if (GV->hasInitializer() && GVAlignment == 0) {
761 if (Alignment < 16) {
762 // If the global is not external, see if it is large. If so, give it a
764 if (getTypeSizeInBits(ElemType) > 128)
765 Alignment = 16; // 16-byte alignment.
771 /// getPreferredAlignmentLog - Return the preferred alignment of the
772 /// specified global, returned in log form. This includes an explicitly
773 /// requested alignment (if the global has one).
774 unsigned DataLayout::getPreferredAlignmentLog(const GlobalVariable *GV) const {
775 return Log2_32(getPreferredAlignment(GV));