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 unsigned 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);
290 assert((AlignType != AGGREGATE_ALIGN || Size == 0) &&
291 "These specifications don't have a size");
294 Split = split(Rest, ':');
295 unsigned ABIAlign = inBytes(getInt(Tok));
297 // Preferred alignment.
298 unsigned PrefAlign = ABIAlign;
300 Split = split(Rest, ':');
301 PrefAlign = inBytes(getInt(Tok));
304 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
308 case 'n': // Native integer types.
310 unsigned Width = getInt(Tok);
311 assert(Width != 0 && "width must be non-zero");
312 LegalIntWidths.push_back(Width);
315 Split = split(Rest, ':');
318 case 'S': { // Stack natural alignment.
319 StackNaturalAlign = inBytes(getInt(Tok));
324 assert(Rest.size() == 1);
327 llvm_unreachable("Unknown mangling in datalayout string");
329 ManglingMode = MM_ELF;
332 ManglingMode = MM_MachO;
335 ManglingMode = MM_Mips;
338 ManglingMode = MM_COFF;
343 llvm_unreachable("Unknown specifier in datalayout string");
351 /// @note This has to exist, because this is a pass, but it should never be
353 DataLayout::DataLayout() : ImmutablePass(ID) {
354 report_fatal_error("Bad DataLayout ctor used. "
355 "Tool did not specify a DataLayout to use?");
358 DataLayout::DataLayout(const Module *M)
359 : ImmutablePass(ID) {
360 init(M->getDataLayout());
364 DataLayout::setAlignment(AlignTypeEnum align_type, unsigned abi_align,
365 unsigned pref_align, uint32_t bit_width) {
366 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
367 assert(pref_align < (1 << 16) && "Alignment doesn't fit in bitfield");
368 assert(bit_width < (1 << 24) && "Bit width doesn't fit in bitfield");
369 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
370 if (Alignments[i].AlignType == (unsigned)align_type &&
371 Alignments[i].TypeBitWidth == bit_width) {
372 // Update the abi, preferred alignments.
373 Alignments[i].ABIAlign = abi_align;
374 Alignments[i].PrefAlign = pref_align;
379 Alignments.push_back(LayoutAlignElem::get(align_type, abi_align,
380 pref_align, bit_width));
383 void DataLayout::setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign,
385 uint32_t TypeByteWidth) {
386 assert(ABIAlign <= PrefAlign && "Preferred alignment worse than ABI!");
387 DenseMap<unsigned,PointerAlignElem>::iterator val = Pointers.find(AddrSpace);
388 if (val == Pointers.end()) {
389 Pointers[AddrSpace] =
390 PointerAlignElem::get(AddrSpace, ABIAlign, PrefAlign, TypeByteWidth);
392 val->second.ABIAlign = ABIAlign;
393 val->second.PrefAlign = PrefAlign;
394 val->second.TypeByteWidth = TypeByteWidth;
398 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
399 /// preferred if ABIInfo = false) the layout wants for the specified datatype.
400 unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
401 uint32_t BitWidth, bool ABIInfo,
403 // Check to see if we have an exact match and remember the best match we see.
404 int BestMatchIdx = -1;
406 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
407 if (Alignments[i].AlignType == (unsigned)AlignType &&
408 Alignments[i].TypeBitWidth == BitWidth)
409 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
411 // The best match so far depends on what we're looking for.
412 if (AlignType == INTEGER_ALIGN &&
413 Alignments[i].AlignType == INTEGER_ALIGN) {
414 // The "best match" for integers is the smallest size that is larger than
415 // the BitWidth requested.
416 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
417 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
419 // However, if there isn't one that's larger, then we must use the
420 // largest one we have (see below)
421 if (LargestInt == -1 ||
422 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
427 // Okay, we didn't find an exact solution. Fall back here depending on what
428 // is being looked for.
429 if (BestMatchIdx == -1) {
430 // If we didn't find an integer alignment, fall back on most conservative.
431 if (AlignType == INTEGER_ALIGN) {
432 BestMatchIdx = LargestInt;
434 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
436 // By default, use natural alignment for vector types. This is consistent
437 // with what clang and llvm-gcc do.
438 unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
439 Align *= cast<VectorType>(Ty)->getNumElements();
440 // If the alignment is not a power of 2, round up to the next power of 2.
441 // This happens for non-power-of-2 length vectors.
442 if (Align & (Align-1))
443 Align = NextPowerOf2(Align);
448 // Since we got a "best match" index, just return it.
449 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
450 : Alignments[BestMatchIdx].PrefAlign;
455 class StructLayoutMap {
456 typedef DenseMap<StructType*, StructLayout*> LayoutInfoTy;
457 LayoutInfoTy LayoutInfo;
460 virtual ~StructLayoutMap() {
461 // Remove any layouts.
462 for (LayoutInfoTy::iterator I = LayoutInfo.begin(), E = LayoutInfo.end();
464 StructLayout *Value = I->second;
465 Value->~StructLayout();
470 StructLayout *&operator[](StructType *STy) {
471 return LayoutInfo[STy];
475 virtual void dump() const {}
478 } // end anonymous namespace
480 DataLayout::~DataLayout() {
481 delete static_cast<StructLayoutMap*>(LayoutMap);
484 bool DataLayout::doFinalization(Module &M) {
485 delete static_cast<StructLayoutMap*>(LayoutMap);
490 const StructLayout *DataLayout::getStructLayout(StructType *Ty) const {
492 LayoutMap = new StructLayoutMap();
494 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
495 StructLayout *&SL = (*STM)[Ty];
498 // Otherwise, create the struct layout. Because it is variable length, we
499 // malloc it, then use placement new.
500 int NumElts = Ty->getNumElements();
502 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
504 // Set SL before calling StructLayout's ctor. The ctor could cause other
505 // entries to be added to TheMap, invalidating our reference.
508 new (L) StructLayout(Ty, *this);
513 std::string DataLayout::getStringRepresentation() const {
515 raw_string_ostream OS(Result);
517 OS << (LittleEndian ? "e" : "E");
519 switch (ManglingMode) {
536 SmallVector<unsigned, 8> addrSpaces;
537 // Lets get all of the known address spaces and sort them
538 // into increasing order so that we can emit the string
539 // in a cleaner format.
540 for (DenseMap<unsigned, PointerAlignElem>::const_iterator
541 pib = Pointers.begin(), pie = Pointers.end();
543 addrSpaces.push_back(pib->first);
545 std::sort(addrSpaces.begin(), addrSpaces.end());
546 for (SmallVectorImpl<unsigned>::iterator asb = addrSpaces.begin(),
547 ase = addrSpaces.end(); asb != ase; ++asb) {
548 const PointerAlignElem &PI = Pointers.find(*asb)->second;
551 if (PI.AddressSpace == 0 && PI.ABIAlign == 8 && PI.PrefAlign == 8 &&
552 PI.TypeByteWidth == 8)
556 if (PI.AddressSpace) {
557 OS << PI.AddressSpace;
559 OS << ":" << PI.TypeByteWidth*8 << ':' << PI.ABIAlign*8;
560 if (PI.PrefAlign != PI.ABIAlign)
561 OS << ':' << PI.PrefAlign*8;
564 const LayoutAlignElem *DefaultStart = DefaultAlignments;
565 const LayoutAlignElem *DefaultEnd =
566 DefaultStart + array_lengthof(DefaultAlignments);
567 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
568 const LayoutAlignElem &AI = Alignments[i];
569 if (std::find(DefaultStart, DefaultEnd, AI) != DefaultEnd)
571 OS << '-' << (char)AI.AlignType;
573 OS << AI.TypeBitWidth;
574 OS << ':' << AI.ABIAlign*8;
575 if (AI.ABIAlign != AI.PrefAlign)
576 OS << ':' << AI.PrefAlign*8;
579 if (!LegalIntWidths.empty()) {
580 OS << "-n" << (unsigned)LegalIntWidths[0];
582 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
583 OS << ':' << (unsigned)LegalIntWidths[i];
586 if (StackNaturalAlign)
587 OS << "-S" << StackNaturalAlign*8;
592 unsigned DataLayout::getPointerTypeSizeInBits(Type *Ty) const {
593 assert(Ty->isPtrOrPtrVectorTy() &&
594 "This should only be called with a pointer or pointer vector type");
596 if (Ty->isPointerTy())
597 return getTypeSizeInBits(Ty);
599 return getTypeSizeInBits(Ty->getScalarType());
603 \param abi_or_pref Flag that determines which alignment is returned. true
604 returns the ABI alignment, false returns the preferred alignment.
605 \param Ty The underlying type for which alignment is determined.
607 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
608 == false) for the requested type \a Ty.
610 unsigned DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
613 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
614 switch (Ty->getTypeID()) {
615 // Early escape for the non-numeric types.
616 case Type::LabelTyID:
618 ? getPointerABIAlignment(0)
619 : getPointerPrefAlignment(0));
620 case Type::PointerTyID: {
621 unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
623 ? getPointerABIAlignment(AS)
624 : getPointerPrefAlignment(AS));
626 case Type::ArrayTyID:
627 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
629 case Type::StructTyID: {
630 // Packed structure types always have an ABI alignment of one.
631 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
634 // Get the layout annotation... which is lazily created on demand.
635 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
636 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
637 return std::max(Align, Layout->getAlignment());
639 case Type::IntegerTyID:
640 AlignType = INTEGER_ALIGN;
643 case Type::FloatTyID:
644 case Type::DoubleTyID:
645 // PPC_FP128TyID and FP128TyID have different data contents, but the
646 // same size and alignment, so they look the same here.
647 case Type::PPC_FP128TyID:
648 case Type::FP128TyID:
649 case Type::X86_FP80TyID:
650 AlignType = FLOAT_ALIGN;
652 case Type::X86_MMXTyID:
653 case Type::VectorTyID:
654 AlignType = VECTOR_ALIGN;
657 llvm_unreachable("Bad type for getAlignment!!!");
660 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
664 unsigned DataLayout::getABITypeAlignment(Type *Ty) const {
665 return getAlignment(Ty, true);
668 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
669 /// an integer type of the specified bitwidth.
670 unsigned DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
671 return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, 0);
674 unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
675 return getAlignment(Ty, false);
678 unsigned DataLayout::getPreferredTypeAlignmentShift(Type *Ty) const {
679 unsigned Align = getPrefTypeAlignment(Ty);
680 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
681 return Log2_32(Align);
684 IntegerType *DataLayout::getIntPtrType(LLVMContext &C,
685 unsigned AddressSpace) const {
686 return IntegerType::get(C, getPointerSizeInBits(AddressSpace));
689 Type *DataLayout::getIntPtrType(Type *Ty) const {
690 assert(Ty->isPtrOrPtrVectorTy() &&
691 "Expected a pointer or pointer vector type.");
692 unsigned NumBits = getTypeSizeInBits(Ty->getScalarType());
693 IntegerType *IntTy = IntegerType::get(Ty->getContext(), NumBits);
694 if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
695 return VectorType::get(IntTy, VecTy->getNumElements());
699 Type *DataLayout::getSmallestLegalIntType(LLVMContext &C, unsigned Width) const {
700 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
701 if (Width <= LegalIntWidths[i])
702 return Type::getIntNTy(C, LegalIntWidths[i]);
706 unsigned DataLayout::getLargestLegalIntTypeSize() const {
707 unsigned MaxWidth = 0;
708 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
709 MaxWidth = std::max<unsigned>(MaxWidth, LegalIntWidths[i]);
713 uint64_t DataLayout::getIndexedOffset(Type *ptrTy,
714 ArrayRef<Value *> Indices) const {
716 assert(Ty->isPointerTy() && "Illegal argument for getIndexedOffset()");
719 generic_gep_type_iterator<Value* const*>
720 TI = gep_type_begin(ptrTy, Indices);
721 for (unsigned CurIDX = 0, EndIDX = Indices.size(); CurIDX != EndIDX;
723 if (StructType *STy = dyn_cast<StructType>(*TI)) {
724 assert(Indices[CurIDX]->getType() ==
725 Type::getInt32Ty(ptrTy->getContext()) &&
726 "Illegal struct idx");
727 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
729 // Get structure layout information...
730 const StructLayout *Layout = getStructLayout(STy);
732 // Add in the offset, as calculated by the structure layout info...
733 Result += Layout->getElementOffset(FieldNo);
735 // Update Ty to refer to current element
736 Ty = STy->getElementType(FieldNo);
738 // Update Ty to refer to current element
739 Ty = cast<SequentialType>(Ty)->getElementType();
741 // Get the array index and the size of each array element.
742 if (int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue())
743 Result += (uint64_t)arrayIdx * getTypeAllocSize(Ty);
750 /// getPreferredAlignment - Return the preferred alignment of the specified
751 /// global. This includes an explicitly requested alignment (if the global
753 unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
754 Type *ElemType = GV->getType()->getElementType();
755 unsigned Alignment = getPrefTypeAlignment(ElemType);
756 unsigned GVAlignment = GV->getAlignment();
757 if (GVAlignment >= Alignment) {
758 Alignment = GVAlignment;
759 } else if (GVAlignment != 0) {
760 Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType));
763 if (GV->hasInitializer() && GVAlignment == 0) {
764 if (Alignment < 16) {
765 // If the global is not external, see if it is large. If so, give it a
767 if (getTypeSizeInBits(ElemType) > 128)
768 Alignment = 16; // 16-byte alignment.
774 /// getPreferredAlignmentLog - Return the preferred alignment of the
775 /// specified global, returned in log form. This includes an explicitly
776 /// requested alignment (if the global has one).
777 unsigned DataLayout::getPreferredAlignmentLog(const GlobalVariable *GV) const {
778 return Log2_32(getPreferredAlignment(GV));