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);
121 TargetAlignElem::dump(std::ostream &os) const {
122 return os << AlignType
124 << ":" << (int) (ABIAlign * 8)
125 << ":" << (int) (PrefAlign * 8);
128 const TargetAlignElem TargetData::InvalidAlignmentElem =
129 TargetAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
131 //===----------------------------------------------------------------------===//
132 // TargetData Class Implementation
133 //===----------------------------------------------------------------------===//
135 /// getInt - Get an integer ignoring errors.
136 static unsigned getInt(StringRef R) {
138 R.getAsInteger(10, Result);
142 void TargetData::init(StringRef Desc) {
144 LittleEndian = false;
147 PointerPrefAlign = PointerABIAlign;
149 // Default alignments
150 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
151 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
152 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
153 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
154 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
155 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
156 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
157 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32, v1i64, ...
158 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
159 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct
161 while (!Desc.empty()) {
162 std::pair<StringRef, StringRef> Split = Desc.split('-');
163 StringRef Token = Split.first;
169 Split = Token.split(':');
170 StringRef Specifier = Split.first;
171 Token = Split.second;
173 assert(!Specifier.empty() && "Can't be empty here");
175 switch (Specifier[0]) {
177 LittleEndian = false;
183 Split = Token.split(':');
184 PointerMemSize = getInt(Split.first) / 8;
185 Split = Split.second.split(':');
186 PointerABIAlign = getInt(Split.first) / 8;
187 Split = Split.second.split(':');
188 PointerPrefAlign = getInt(Split.first) / 8;
189 if (PointerPrefAlign == 0)
190 PointerPrefAlign = PointerABIAlign;
197 AlignTypeEnum AlignType;
198 switch (Specifier[0]) {
200 case 'i': AlignType = INTEGER_ALIGN; break;
201 case 'v': AlignType = VECTOR_ALIGN; break;
202 case 'f': AlignType = FLOAT_ALIGN; break;
203 case 'a': AlignType = AGGREGATE_ALIGN; break;
204 case 's': AlignType = STACK_ALIGN; break;
206 unsigned Size = getInt(Specifier.substr(1));
207 Split = Token.split(':');
208 unsigned char ABIAlign = getInt(Split.first) / 8;
210 Split = Split.second.split(':');
211 unsigned char PrefAlign = getInt(Split.first) / 8;
213 PrefAlign = ABIAlign;
214 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
217 case 'n': // Native integer types.
218 Specifier = Specifier.substr(1);
220 if (unsigned Width = getInt(Specifier))
221 LegalIntWidths.push_back(Width);
222 Split = Token.split(':');
223 Specifier = Split.first;
224 Token = Split.second;
225 } while (!Specifier.empty() || !Token.empty());
236 /// @note This has to exist, because this is a pass, but it should never be
238 TargetData::TargetData() : ImmutablePass(&ID) {
239 llvm_report_error("Bad TargetData ctor used. "
240 "Tool did not specify a TargetData to use?");
243 TargetData::TargetData(const Module *M)
244 : ImmutablePass(&ID) {
245 init(M->getDataLayout());
249 TargetData::setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
250 unsigned char pref_align, uint32_t bit_width) {
251 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
252 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
253 if (Alignments[i].AlignType == align_type &&
254 Alignments[i].TypeBitWidth == bit_width) {
255 // Update the abi, preferred alignments.
256 Alignments[i].ABIAlign = abi_align;
257 Alignments[i].PrefAlign = pref_align;
262 Alignments.push_back(TargetAlignElem::get(align_type, abi_align,
263 pref_align, bit_width));
266 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
267 /// preferred if ABIInfo = false) the target wants for the specified datatype.
268 unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
269 uint32_t BitWidth, bool ABIInfo,
270 const Type *Ty) const {
271 // Check to see if we have an exact match and remember the best match we see.
272 int BestMatchIdx = -1;
274 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
275 if (Alignments[i].AlignType == AlignType &&
276 Alignments[i].TypeBitWidth == BitWidth)
277 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
279 // The best match so far depends on what we're looking for.
280 if (AlignType == VECTOR_ALIGN && Alignments[i].AlignType == VECTOR_ALIGN) {
281 // If this is a specification for a smaller vector type, we will fall back
282 // to it. This happens because <128 x double> can be implemented in terms
283 // of 64 <2 x double>.
284 if (Alignments[i].TypeBitWidth < BitWidth) {
285 // Verify that we pick the biggest of the fallbacks.
286 if (BestMatchIdx == -1 ||
287 Alignments[BestMatchIdx].TypeBitWidth < Alignments[i].TypeBitWidth)
290 } else if (AlignType == INTEGER_ALIGN &&
291 Alignments[i].AlignType == INTEGER_ALIGN) {
292 // The "best match" for integers is the smallest size that is larger than
293 // the BitWidth requested.
294 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
295 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
297 // However, if there isn't one that's larger, then we must use the
298 // largest one we have (see below)
299 if (LargestInt == -1 ||
300 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
305 // Okay, we didn't find an exact solution. Fall back here depending on what
306 // is being looked for.
307 if (BestMatchIdx == -1) {
308 // If we didn't find an integer alignment, fall back on most conservative.
309 if (AlignType == INTEGER_ALIGN) {
310 BestMatchIdx = LargestInt;
312 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
314 // If we didn't find a vector size that is smaller or equal to this type,
315 // then we will end up scalarizing this to its element type. Just return
316 // the alignment of the element.
317 return getAlignment(cast<VectorType>(Ty)->getElementType(), ABIInfo);
321 // Since we got a "best match" index, just return it.
322 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
323 : Alignments[BestMatchIdx].PrefAlign;
326 typedef DenseMap<const StructType*, StructLayout*> LayoutInfoTy;
330 class StructLayoutMap : public AbstractTypeUser {
331 LayoutInfoTy LayoutInfo;
333 /// refineAbstractType - The callback method invoked when an abstract type is
334 /// resolved to another type. An object must override this method to update
335 /// its internal state to reference NewType instead of OldType.
337 virtual void refineAbstractType(const DerivedType *OldTy,
339 const StructType *STy = dyn_cast<const StructType>(OldTy);
340 assert(STy && "This can only track struct types.");
342 LayoutInfoTy::iterator Iter = LayoutInfo.find(STy);
343 Iter->second->~StructLayout();
345 LayoutInfo.erase(Iter);
346 OldTy->removeAbstractTypeUser(this);
349 /// typeBecameConcrete - The other case which AbstractTypeUsers must be aware
350 /// of is when a type makes the transition from being abstract (where it has
351 /// clients on its AbstractTypeUsers list) to concrete (where it does not).
352 /// This method notifies ATU's when this occurs for a type.
354 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
355 const StructType *STy = dyn_cast<const StructType>(AbsTy);
356 assert(STy && "This can only track struct types.");
358 LayoutInfoTy::iterator Iter = LayoutInfo.find(STy);
359 Iter->second->~StructLayout();
361 LayoutInfo.erase(Iter);
362 AbsTy->removeAbstractTypeUser(this);
366 virtual ~StructLayoutMap() {
367 // Remove any layouts.
368 for (LayoutInfoTy::iterator
369 I = LayoutInfo.begin(), E = LayoutInfo.end(); I != E; ++I) {
370 const Type *Key = I->first;
371 StructLayout *Value = I->second;
373 if (Key && Key->isAbstract())
374 Key->removeAbstractTypeUser(this);
377 Value->~StructLayout();
383 LayoutInfoTy::iterator end() {
384 return LayoutInfo.end();
387 LayoutInfoTy::iterator find(const StructType *&Val) {
388 return LayoutInfo.find(Val);
391 bool erase(LayoutInfoTy::iterator I) {
392 return LayoutInfo.erase(I);
395 StructLayout *&operator[](const StructType *STy) {
396 return LayoutInfo[STy];
400 virtual void dump() const {}
403 } // end namespace llvm
405 TargetData::~TargetData() {
406 delete static_cast<StructLayoutMap*>(LayoutMap);
409 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
411 LayoutMap = new StructLayoutMap();
413 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
414 StructLayout *&SL = (*STM)[Ty];
417 // Otherwise, create the struct layout. Because it is variable length, we
418 // malloc it, then use placement new.
419 int NumElts = Ty->getNumElements();
421 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
423 // Set SL before calling StructLayout's ctor. The ctor could cause other
424 // entries to be added to TheMap, invalidating our reference.
427 new (L) StructLayout(Ty, *this);
429 if (Ty->isAbstract())
430 Ty->addAbstractTypeUser(STM);
435 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
436 /// objects. If a TargetData object is alive when types are being refined and
437 /// removed, this method must be called whenever a StructType is removed to
438 /// avoid a dangling pointer in this cache.
439 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
440 if (!LayoutMap) return; // No cache.
442 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
443 LayoutInfoTy::iterator I = STM->find(Ty);
444 if (I == STM->end()) return;
446 I->second->~StructLayout();
450 if (Ty->isAbstract())
451 Ty->removeAbstractTypeUser(STM);
454 std::string TargetData::getStringRepresentation() const {
456 raw_string_ostream OS(Result);
458 OS << (LittleEndian ? "e" : "E")
459 << "-p:" << PointerMemSize*8 << ':' << PointerABIAlign*8
460 << ':' << PointerPrefAlign*8;
461 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
462 const TargetAlignElem &AI = Alignments[i];
463 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
464 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
467 if (!LegalIntWidths.empty()) {
468 OS << "-n" << (unsigned)LegalIntWidths[0];
470 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
471 OS << ':' << (unsigned)LegalIntWidths[i];
477 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
478 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
479 switch (Ty->getTypeID()) {
480 case Type::LabelTyID:
481 case Type::PointerTyID:
482 return getPointerSizeInBits();
483 case Type::ArrayTyID: {
484 const ArrayType *ATy = cast<ArrayType>(Ty);
485 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
487 case Type::StructTyID:
488 // Get the layout annotation... which is lazily created on demand.
489 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
490 case Type::IntegerTyID:
491 return cast<IntegerType>(Ty)->getBitWidth();
494 case Type::FloatTyID:
496 case Type::DoubleTyID:
498 case Type::PPC_FP128TyID:
499 case Type::FP128TyID:
501 // In memory objects this is always aligned to a higher boundary, but
502 // only 80 bits contain information.
503 case Type::X86_FP80TyID:
505 case Type::VectorTyID:
506 return cast<VectorType>(Ty)->getBitWidth();
508 llvm_unreachable("TargetData::getTypeSizeInBits(): Unsupported type");
515 \param abi_or_pref Flag that determines which alignment is returned. true
516 returns the ABI alignment, false returns the preferred alignment.
517 \param Ty The underlying type for which alignment is determined.
519 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
520 == false) for the requested type \a Ty.
522 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
525 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
526 switch (Ty->getTypeID()) {
527 // Early escape for the non-numeric types.
528 case Type::LabelTyID:
529 case Type::PointerTyID:
531 ? getPointerABIAlignment()
532 : getPointerPrefAlignment());
533 case Type::ArrayTyID:
534 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
536 case Type::StructTyID: {
537 // Packed structure types always have an ABI alignment of one.
538 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
541 // Get the layout annotation... which is lazily created on demand.
542 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
543 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
544 return std::max(Align, (unsigned)Layout->getAlignment());
546 case Type::IntegerTyID:
548 AlignType = INTEGER_ALIGN;
550 case Type::FloatTyID:
551 case Type::DoubleTyID:
552 // PPC_FP128TyID and FP128TyID have different data contents, but the
553 // same size and alignment, so they look the same here.
554 case Type::PPC_FP128TyID:
555 case Type::FP128TyID:
556 case Type::X86_FP80TyID:
557 AlignType = FLOAT_ALIGN;
559 case Type::VectorTyID:
560 AlignType = VECTOR_ALIGN;
563 llvm_unreachable("Bad type for getAlignment!!!");
567 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
571 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
572 return getAlignment(Ty, true);
575 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
576 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
577 if (Alignments[i].AlignType == STACK_ALIGN)
578 return Alignments[i].ABIAlign;
580 return getABITypeAlignment(Ty);
583 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
584 return getAlignment(Ty, false);
587 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
588 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
589 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
590 return Log2_32(Align);
593 /// getIntPtrType - Return an unsigned integer type that is the same size or
594 /// greater to the host pointer size.
595 const IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
596 return IntegerType::get(C, getPointerSizeInBits());
600 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
601 unsigned NumIndices) const {
602 const Type *Ty = ptrTy;
603 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
606 generic_gep_type_iterator<Value* const*>
607 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
608 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
609 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
610 assert(Indices[CurIDX]->getType() ==
611 Type::getInt32Ty(ptrTy->getContext()) &&
612 "Illegal struct idx");
613 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
615 // Get structure layout information...
616 const StructLayout *Layout = getStructLayout(STy);
618 // Add in the offset, as calculated by the structure layout info...
619 Result += Layout->getElementOffset(FieldNo);
621 // Update Ty to refer to current element
622 Ty = STy->getElementType(FieldNo);
624 // Update Ty to refer to current element
625 Ty = cast<SequentialType>(Ty)->getElementType();
627 // Get the array index and the size of each array element.
628 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
629 Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
636 /// getPreferredAlignment - Return the preferred alignment of the specified
637 /// global. This includes an explicitly requested alignment (if the global
639 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
640 const Type *ElemType = GV->getType()->getElementType();
641 unsigned Alignment = getPrefTypeAlignment(ElemType);
642 if (GV->getAlignment() > Alignment)
643 Alignment = GV->getAlignment();
645 if (GV->hasInitializer()) {
646 if (Alignment < 16) {
647 // If the global is not external, see if it is large. If so, give it a
649 if (getTypeSizeInBits(ElemType) > 128)
650 Alignment = 16; // 16-byte alignment.
656 /// getPreferredAlignmentLog - Return the preferred alignment of the
657 /// specified global, returned in log form. This includes an explicitly
658 /// requested alignment (if the global has one).
659 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
660 return Log2_32(getPreferredAlignment(GV));