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;
320 class StructLayoutMap : public AbstractTypeUser {
321 typedef DenseMap<const StructType*, StructLayout*> LayoutInfoTy;
322 LayoutInfoTy LayoutInfo;
324 /// refineAbstractType - The callback method invoked when an abstract type is
325 /// resolved to another type. An object must override this method to update
326 /// its internal state to reference NewType instead of OldType.
328 virtual void refineAbstractType(const DerivedType *OldTy,
330 const StructType *STy = cast<const StructType>(OldTy);
331 LayoutInfoTy::iterator Iter = LayoutInfo.find(STy);
332 Iter->second->~StructLayout();
334 LayoutInfo.erase(Iter);
335 OldTy->removeAbstractTypeUser(this);
338 /// typeBecameConcrete - The other case which AbstractTypeUsers must be aware
339 /// of is when a type makes the transition from being abstract (where it has
340 /// clients on its AbstractTypeUsers list) to concrete (where it does not).
341 /// This method notifies ATU's when this occurs for a type.
343 virtual void typeBecameConcrete(const DerivedType *AbsTy) {
344 const StructType *STy = cast<const StructType>(AbsTy);
345 LayoutInfoTy::iterator Iter = LayoutInfo.find(STy);
346 Iter->second->~StructLayout();
348 LayoutInfo.erase(Iter);
349 AbsTy->removeAbstractTypeUser(this);
353 virtual ~StructLayoutMap() {
354 // Remove any layouts.
355 for (LayoutInfoTy::iterator
356 I = LayoutInfo.begin(), E = LayoutInfo.end(); I != E; ++I) {
357 const Type *Key = I->first;
358 StructLayout *Value = I->second;
360 if (Key->isAbstract())
361 Key->removeAbstractTypeUser(this);
363 Value->~StructLayout();
368 void InvalidateEntry(const StructType *Ty) {
369 LayoutInfoTy::iterator I = LayoutInfo.find(Ty);
370 if (I == LayoutInfo.end()) return;
372 I->second->~StructLayout();
376 if (Ty->isAbstract())
377 Ty->removeAbstractTypeUser(this);
380 StructLayout *&operator[](const StructType *STy) {
381 return LayoutInfo[STy];
385 virtual void dump() const {}
388 } // end anonymous namespace
390 TargetData::~TargetData() {
391 delete static_cast<StructLayoutMap*>(LayoutMap);
394 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
396 LayoutMap = new StructLayoutMap();
398 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
399 StructLayout *&SL = (*STM)[Ty];
402 // Otherwise, create the struct layout. Because it is variable length, we
403 // malloc it, then use placement new.
404 int NumElts = Ty->getNumElements();
406 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
408 // Set SL before calling StructLayout's ctor. The ctor could cause other
409 // entries to be added to TheMap, invalidating our reference.
412 new (L) StructLayout(Ty, *this);
414 if (Ty->isAbstract())
415 Ty->addAbstractTypeUser(STM);
420 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
421 /// objects. If a TargetData object is alive when types are being refined and
422 /// removed, this method must be called whenever a StructType is removed to
423 /// avoid a dangling pointer in this cache.
424 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
425 if (!LayoutMap) return; // No cache.
427 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
428 STM->InvalidateEntry(Ty);
431 std::string TargetData::getStringRepresentation() const {
433 raw_string_ostream OS(Result);
435 OS << (LittleEndian ? "e" : "E")
436 << "-p:" << PointerMemSize*8 << ':' << PointerABIAlign*8
437 << ':' << PointerPrefAlign*8;
438 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
439 const TargetAlignElem &AI = Alignments[i];
440 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
441 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
444 if (!LegalIntWidths.empty()) {
445 OS << "-n" << (unsigned)LegalIntWidths[0];
447 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
448 OS << ':' << (unsigned)LegalIntWidths[i];
454 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
455 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
456 switch (Ty->getTypeID()) {
457 case Type::LabelTyID:
458 case Type::PointerTyID:
459 return getPointerSizeInBits();
460 case Type::ArrayTyID: {
461 const ArrayType *ATy = cast<ArrayType>(Ty);
462 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
464 case Type::StructTyID:
465 // Get the layout annotation... which is lazily created on demand.
466 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
467 case Type::IntegerTyID:
468 return cast<IntegerType>(Ty)->getBitWidth();
471 case Type::FloatTyID:
473 case Type::DoubleTyID:
475 case Type::PPC_FP128TyID:
476 case Type::FP128TyID:
478 // In memory objects this is always aligned to a higher boundary, but
479 // only 80 bits contain information.
480 case Type::X86_FP80TyID:
482 case Type::VectorTyID:
483 return cast<VectorType>(Ty)->getBitWidth();
485 llvm_unreachable("TargetData::getTypeSizeInBits(): Unsupported type");
492 \param abi_or_pref Flag that determines which alignment is returned. true
493 returns the ABI alignment, false returns the preferred alignment.
494 \param Ty The underlying type for which alignment is determined.
496 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
497 == false) for the requested type \a Ty.
499 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
502 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
503 switch (Ty->getTypeID()) {
504 // Early escape for the non-numeric types.
505 case Type::LabelTyID:
506 case Type::PointerTyID:
508 ? getPointerABIAlignment()
509 : getPointerPrefAlignment());
510 case Type::ArrayTyID:
511 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
513 case Type::StructTyID: {
514 // Packed structure types always have an ABI alignment of one.
515 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
518 // Get the layout annotation... which is lazily created on demand.
519 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
520 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
521 return std::max(Align, (unsigned)Layout->getAlignment());
523 case Type::IntegerTyID:
525 AlignType = INTEGER_ALIGN;
527 case Type::FloatTyID:
528 case Type::DoubleTyID:
529 // PPC_FP128TyID and FP128TyID have different data contents, but the
530 // same size and alignment, so they look the same here.
531 case Type::PPC_FP128TyID:
532 case Type::FP128TyID:
533 case Type::X86_FP80TyID:
534 AlignType = FLOAT_ALIGN;
536 case Type::VectorTyID:
537 AlignType = VECTOR_ALIGN;
540 llvm_unreachable("Bad type for getAlignment!!!");
544 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
548 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
549 return getAlignment(Ty, true);
552 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
553 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
554 if (Alignments[i].AlignType == STACK_ALIGN)
555 return Alignments[i].ABIAlign;
557 return getABITypeAlignment(Ty);
560 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
561 return getAlignment(Ty, false);
564 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
565 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
566 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
567 return Log2_32(Align);
570 /// getIntPtrType - Return an unsigned integer type that is the same size or
571 /// greater to the host pointer size.
572 const IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
573 return IntegerType::get(C, getPointerSizeInBits());
577 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
578 unsigned NumIndices) const {
579 const Type *Ty = ptrTy;
580 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
583 generic_gep_type_iterator<Value* const*>
584 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
585 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
586 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
587 assert(Indices[CurIDX]->getType() ==
588 Type::getInt32Ty(ptrTy->getContext()) &&
589 "Illegal struct idx");
590 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
592 // Get structure layout information...
593 const StructLayout *Layout = getStructLayout(STy);
595 // Add in the offset, as calculated by the structure layout info...
596 Result += Layout->getElementOffset(FieldNo);
598 // Update Ty to refer to current element
599 Ty = STy->getElementType(FieldNo);
601 // Update Ty to refer to current element
602 Ty = cast<SequentialType>(Ty)->getElementType();
604 // Get the array index and the size of each array element.
605 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
606 Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
613 /// getPreferredAlignment - Return the preferred alignment of the specified
614 /// global. This includes an explicitly requested alignment (if the global
616 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
617 const Type *ElemType = GV->getType()->getElementType();
618 unsigned Alignment = getPrefTypeAlignment(ElemType);
619 if (GV->getAlignment() > Alignment)
620 Alignment = GV->getAlignment();
622 if (GV->hasInitializer()) {
623 if (Alignment < 16) {
624 // If the global is not external, see if it is large. If so, give it a
626 if (getTypeSizeInBits(ElemType) > 128)
627 Alignment = 16; // 16-byte alignment.
633 /// getPreferredAlignmentLog - Return the preferred alignment of the
634 /// specified global, returned in log form. This includes an explicitly
635 /// requested alignment (if the global has one).
636 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
637 return Log2_32(getPreferredAlignment(GV));