1 //===-- TargetData.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 target 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/Target/TargetData.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/System/Mutex.h"
29 #include "llvm/ADT/DenseMap.h"
34 // Handle the Pass registration stuff necessary to use TargetData's.
36 // Register the default SparcV9 implementation...
37 static RegisterPass<TargetData> X("targetdata", "Target Data Layout", false,
39 char TargetData::ID = 0;
41 //===----------------------------------------------------------------------===//
42 // Support for StructLayout
43 //===----------------------------------------------------------------------===//
45 StructLayout::StructLayout(const StructType *ST, const TargetData &TD) {
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 const 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 = TargetData::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 = TargetData::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 // TargetAlignElem, TargetAlign support
98 //===----------------------------------------------------------------------===//
101 TargetAlignElem::get(AlignTypeEnum align_type, unsigned char abi_align,
102 unsigned char pref_align, uint32_t bit_width) {
103 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
104 TargetAlignElem retval;
105 retval.AlignType = align_type;
106 retval.ABIAlign = abi_align;
107 retval.PrefAlign = pref_align;
108 retval.TypeBitWidth = bit_width;
113 TargetAlignElem::operator==(const TargetAlignElem &rhs) const {
114 return (AlignType == rhs.AlignType
115 && ABIAlign == rhs.ABIAlign
116 && PrefAlign == rhs.PrefAlign
117 && TypeBitWidth == rhs.TypeBitWidth);
120 const TargetAlignElem TargetData::InvalidAlignmentElem =
121 TargetAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
123 //===----------------------------------------------------------------------===//
124 // TargetData Class Implementation
125 //===----------------------------------------------------------------------===//
127 /// getInt - Get an integer ignoring errors.
128 static unsigned getInt(StringRef R) {
130 R.getAsInteger(10, Result);
134 void TargetData::init(StringRef Desc) {
136 LittleEndian = false;
139 PointerPrefAlign = PointerABIAlign;
141 // Default alignments
142 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
143 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
144 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
145 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
146 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
147 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
148 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
149 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32, v1i64, ...
150 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
151 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct
153 while (!Desc.empty()) {
154 std::pair<StringRef, StringRef> Split = Desc.split('-');
155 StringRef Token = Split.first;
161 Split = Token.split(':');
162 StringRef Specifier = Split.first;
163 Token = Split.second;
165 assert(!Specifier.empty() && "Can't be empty here");
167 switch (Specifier[0]) {
169 LittleEndian = false;
175 Split = Token.split(':');
176 PointerMemSize = getInt(Split.first) / 8;
177 Split = Split.second.split(':');
178 PointerABIAlign = getInt(Split.first) / 8;
179 Split = Split.second.split(':');
180 PointerPrefAlign = getInt(Split.first) / 8;
181 if (PointerPrefAlign == 0)
182 PointerPrefAlign = PointerABIAlign;
189 AlignTypeEnum AlignType;
190 switch (Specifier[0]) {
192 case 'i': AlignType = INTEGER_ALIGN; break;
193 case 'v': AlignType = VECTOR_ALIGN; break;
194 case 'f': AlignType = FLOAT_ALIGN; break;
195 case 'a': AlignType = AGGREGATE_ALIGN; break;
196 case 's': AlignType = STACK_ALIGN; break;
198 unsigned Size = getInt(Specifier.substr(1));
199 Split = Token.split(':');
200 unsigned char ABIAlign = getInt(Split.first) / 8;
202 Split = Split.second.split(':');
203 unsigned char PrefAlign = getInt(Split.first) / 8;
205 PrefAlign = ABIAlign;
206 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
209 case 'n': // Native integer types.
210 Specifier = Specifier.substr(1);
212 if (unsigned Width = getInt(Specifier))
213 LegalIntWidths.push_back(Width);
214 Split = Token.split(':');
215 Specifier = Split.first;
216 Token = Split.second;
217 } while (!Specifier.empty() || !Token.empty());
228 /// @note This has to exist, because this is a pass, but it should never be
230 TargetData::TargetData() : ImmutablePass(&ID) {
231 llvm_report_error("Bad TargetData ctor used. "
232 "Tool did not specify a TargetData to use?");
235 TargetData::TargetData(const Module *M)
236 : ImmutablePass(&ID) {
237 init(M->getDataLayout());
241 TargetData::setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
242 unsigned char pref_align, uint32_t bit_width) {
243 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
244 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
245 if (Alignments[i].AlignType == align_type &&
246 Alignments[i].TypeBitWidth == bit_width) {
247 // Update the abi, preferred alignments.
248 Alignments[i].ABIAlign = abi_align;
249 Alignments[i].PrefAlign = pref_align;
254 Alignments.push_back(TargetAlignElem::get(align_type, abi_align,
255 pref_align, bit_width));
258 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
259 /// preferred if ABIInfo = false) the target wants for the specified datatype.
260 unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
261 uint32_t BitWidth, bool ABIInfo,
262 const Type *Ty) const {
263 // Check to see if we have an exact match and remember the best match we see.
264 int BestMatchIdx = -1;
266 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
267 if (Alignments[i].AlignType == AlignType &&
268 Alignments[i].TypeBitWidth == BitWidth)
269 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
271 // The best match so far depends on what we're looking for.
272 if (AlignType == VECTOR_ALIGN && Alignments[i].AlignType == VECTOR_ALIGN) {
273 // If this is a specification for a smaller vector type, we will fall back
274 // to it. This happens because <128 x double> can be implemented in terms
275 // of 64 <2 x double>.
276 if (Alignments[i].TypeBitWidth < BitWidth) {
277 // Verify that we pick the biggest of the fallbacks.
278 if (BestMatchIdx == -1 ||
279 Alignments[BestMatchIdx].TypeBitWidth < Alignments[i].TypeBitWidth)
282 } else if (AlignType == INTEGER_ALIGN &&
283 Alignments[i].AlignType == INTEGER_ALIGN) {
284 // The "best match" for integers is the smallest size that is larger than
285 // the BitWidth requested.
286 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
287 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
289 // However, if there isn't one that's larger, then we must use the
290 // largest one we have (see below)
291 if (LargestInt == -1 ||
292 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
297 // Okay, we didn't find an exact solution. Fall back here depending on what
298 // is being looked for.
299 if (BestMatchIdx == -1) {
300 // If we didn't find an integer alignment, fall back on most conservative.
301 if (AlignType == INTEGER_ALIGN) {
302 BestMatchIdx = LargestInt;
304 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
306 // If we didn't find a vector size that is smaller or equal to this type,
307 // then we will end up scalarizing this to its element type. Just return
308 // the alignment of the element.
309 return getAlignment(cast<VectorType>(Ty)->getElementType(), ABIInfo);
313 // Since we got a "best match" index, just return it.
314 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
315 : Alignments[BestMatchIdx].PrefAlign;
318 typedef DenseMap<const StructType*, StructLayout*> LayoutInfoTy;
322 class StructLayoutMap : public AbstractTypeUser {
323 LayoutInfoTy LayoutInfo;
325 /// refineAbstractType - The callback method invoked when an abstract type is
326 /// resolved to another type. An object must override this method to update
327 /// its internal state to reference NewType instead of OldType.
329 virtual void refineAbstractType(const DerivedType *OldTy,
331 const StructType *STy = dyn_cast<const StructType>(OldTy);
332 assert(STy && "This can only track struct types.");
334 LayoutInfoTy::iterator Iter = LayoutInfo.find(STy);
335 Iter->second->~StructLayout();
337 LayoutInfo.erase(Iter);
338 OldTy->removeAbstractTypeUser(this);
341 /// typeBecameConcrete - The other case which AbstractTypeUsers must be aware
342 /// of is when a type makes the transition from being abstract (where it has
343 /// clients on its AbstractTypeUsers list) to concrete (where it does not).
344 /// This method notifies ATU's when this occurs for a type.
346 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
347 const StructType *STy = dyn_cast<const StructType>(AbsTy);
348 assert(STy && "This can only track struct types.");
350 LayoutInfoTy::iterator Iter = LayoutInfo.find(STy);
351 Iter->second->~StructLayout();
353 LayoutInfo.erase(Iter);
354 AbsTy->removeAbstractTypeUser(this);
358 virtual ~StructLayoutMap() {
359 // Remove any layouts.
360 for (LayoutInfoTy::iterator
361 I = LayoutInfo.begin(), E = LayoutInfo.end(); I != E; ++I) {
362 const Type *Key = I->first;
363 StructLayout *Value = I->second;
365 if (Key && Key->isAbstract())
366 Key->removeAbstractTypeUser(this);
369 Value->~StructLayout();
375 LayoutInfoTy::iterator end() {
376 return LayoutInfo.end();
379 LayoutInfoTy::iterator find(const StructType *&Val) {
380 return LayoutInfo.find(Val);
383 bool erase(LayoutInfoTy::iterator I) {
384 return LayoutInfo.erase(I);
387 StructLayout *&operator[](const StructType *STy) {
388 return LayoutInfo[STy];
392 virtual void dump() const {}
395 } // end namespace llvm
397 TargetData::~TargetData() {
398 delete static_cast<StructLayoutMap*>(LayoutMap);
401 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
403 LayoutMap = new StructLayoutMap();
405 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
406 StructLayout *&SL = (*STM)[Ty];
409 // Otherwise, create the struct layout. Because it is variable length, we
410 // malloc it, then use placement new.
411 int NumElts = Ty->getNumElements();
413 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
415 // Set SL before calling StructLayout's ctor. The ctor could cause other
416 // entries to be added to TheMap, invalidating our reference.
419 new (L) StructLayout(Ty, *this);
421 if (Ty->isAbstract())
422 Ty->addAbstractTypeUser(STM);
427 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
428 /// objects. If a TargetData object is alive when types are being refined and
429 /// removed, this method must be called whenever a StructType is removed to
430 /// avoid a dangling pointer in this cache.
431 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
432 if (!LayoutMap) return; // No cache.
434 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
435 LayoutInfoTy::iterator I = STM->find(Ty);
436 if (I == STM->end()) return;
438 I->second->~StructLayout();
442 if (Ty->isAbstract())
443 Ty->removeAbstractTypeUser(STM);
446 std::string TargetData::getStringRepresentation() const {
448 raw_string_ostream OS(Result);
450 OS << (LittleEndian ? "e" : "E")
451 << "-p:" << PointerMemSize*8 << ':' << PointerABIAlign*8
452 << ':' << PointerPrefAlign*8;
453 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
454 const TargetAlignElem &AI = Alignments[i];
455 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
456 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
459 if (!LegalIntWidths.empty()) {
460 OS << "-n" << (unsigned)LegalIntWidths[0];
462 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
463 OS << ':' << (unsigned)LegalIntWidths[i];
469 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
470 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
471 switch (Ty->getTypeID()) {
472 case Type::LabelTyID:
473 case Type::PointerTyID:
474 return getPointerSizeInBits();
475 case Type::ArrayTyID: {
476 const ArrayType *ATy = cast<ArrayType>(Ty);
477 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
479 case Type::StructTyID:
480 // Get the layout annotation... which is lazily created on demand.
481 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
482 case Type::IntegerTyID:
483 return cast<IntegerType>(Ty)->getBitWidth();
486 case Type::FloatTyID:
488 case Type::DoubleTyID:
490 case Type::PPC_FP128TyID:
491 case Type::FP128TyID:
493 // In memory objects this is always aligned to a higher boundary, but
494 // only 80 bits contain information.
495 case Type::X86_FP80TyID:
497 case Type::VectorTyID:
498 return cast<VectorType>(Ty)->getBitWidth();
500 llvm_unreachable("TargetData::getTypeSizeInBits(): Unsupported type");
507 \param abi_or_pref Flag that determines which alignment is returned. true
508 returns the ABI alignment, false returns the preferred alignment.
509 \param Ty The underlying type for which alignment is determined.
511 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
512 == false) for the requested type \a Ty.
514 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
517 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
518 switch (Ty->getTypeID()) {
519 // Early escape for the non-numeric types.
520 case Type::LabelTyID:
521 case Type::PointerTyID:
523 ? getPointerABIAlignment()
524 : getPointerPrefAlignment());
525 case Type::ArrayTyID:
526 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
528 case Type::StructTyID: {
529 // Packed structure types always have an ABI alignment of one.
530 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
533 // Get the layout annotation... which is lazily created on demand.
534 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
535 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
536 return std::max(Align, (unsigned)Layout->getAlignment());
538 case Type::IntegerTyID:
540 AlignType = INTEGER_ALIGN;
542 case Type::FloatTyID:
543 case Type::DoubleTyID:
544 // PPC_FP128TyID and FP128TyID have different data contents, but the
545 // same size and alignment, so they look the same here.
546 case Type::PPC_FP128TyID:
547 case Type::FP128TyID:
548 case Type::X86_FP80TyID:
549 AlignType = FLOAT_ALIGN;
551 case Type::VectorTyID:
552 AlignType = VECTOR_ALIGN;
555 llvm_unreachable("Bad type for getAlignment!!!");
559 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
563 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
564 return getAlignment(Ty, true);
567 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
568 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
569 if (Alignments[i].AlignType == STACK_ALIGN)
570 return Alignments[i].ABIAlign;
572 return getABITypeAlignment(Ty);
575 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
576 return getAlignment(Ty, false);
579 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
580 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
581 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
582 return Log2_32(Align);
585 /// getIntPtrType - Return an unsigned integer type that is the same size or
586 /// greater to the host pointer size.
587 const IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
588 return IntegerType::get(C, getPointerSizeInBits());
592 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
593 unsigned NumIndices) const {
594 const Type *Ty = ptrTy;
595 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
598 generic_gep_type_iterator<Value* const*>
599 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
600 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
601 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
602 assert(Indices[CurIDX]->getType() ==
603 Type::getInt32Ty(ptrTy->getContext()) &&
604 "Illegal struct idx");
605 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
607 // Get structure layout information...
608 const StructLayout *Layout = getStructLayout(STy);
610 // Add in the offset, as calculated by the structure layout info...
611 Result += Layout->getElementOffset(FieldNo);
613 // Update Ty to refer to current element
614 Ty = STy->getElementType(FieldNo);
616 // Update Ty to refer to current element
617 Ty = cast<SequentialType>(Ty)->getElementType();
619 // Get the array index and the size of each array element.
620 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
621 Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
628 /// getPreferredAlignment - Return the preferred alignment of the specified
629 /// global. This includes an explicitly requested alignment (if the global
631 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
632 const Type *ElemType = GV->getType()->getElementType();
633 unsigned Alignment = getPrefTypeAlignment(ElemType);
634 if (GV->getAlignment() > Alignment)
635 Alignment = GV->getAlignment();
637 if (GV->hasInitializer()) {
638 if (Alignment < 16) {
639 // If the global is not external, see if it is large. If so, give it a
641 if (getTypeSizeInBits(ElemType) > 128)
642 Alignment = 16; // 16-byte alignment.
648 /// getPreferredAlignmentLog - Return the preferred alignment of the
649 /// specified global, returned in log form. This includes an explicitly
650 /// requested alignment (if the global has one).
651 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
652 return Log2_32(getPreferredAlignment(GV));