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 INITIALIZE_PASS(TargetData, "targetdata", "Target Data Layout", false, true);
38 char TargetData::ID = 0;
40 //===----------------------------------------------------------------------===//
41 // Support for StructLayout
42 //===----------------------------------------------------------------------===//
44 StructLayout::StructLayout(const StructType *ST, const TargetData &TD) {
47 NumElements = ST->getNumElements();
49 // Loop over each of the elements, placing them in memory.
50 for (unsigned i = 0, e = NumElements; i != e; ++i) {
51 const Type *Ty = ST->getElementType(i);
52 unsigned TyAlign = ST->isPacked() ? 1 : TD.getABITypeAlignment(Ty);
54 // Add padding if necessary to align the data element properly.
55 if ((StructSize & (TyAlign-1)) != 0)
56 StructSize = TargetData::RoundUpAlignment(StructSize, TyAlign);
58 // Keep track of maximum alignment constraint.
59 StructAlignment = std::max(TyAlign, StructAlignment);
61 MemberOffsets[i] = StructSize;
62 StructSize += TD.getTypeAllocSize(Ty); // Consume space for this data item
65 // Empty structures have alignment of 1 byte.
66 if (StructAlignment == 0) StructAlignment = 1;
68 // Add padding to the end of the struct so that it could be put in an array
69 // and all array elements would be aligned correctly.
70 if ((StructSize & (StructAlignment-1)) != 0)
71 StructSize = TargetData::RoundUpAlignment(StructSize, StructAlignment);
75 /// getElementContainingOffset - Given a valid offset into the structure,
76 /// return the structure index that contains it.
77 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
79 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
80 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
82 assert(*SI <= Offset && "upper_bound didn't work");
83 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
84 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
85 "Upper bound didn't work!");
87 // Multiple fields can have the same offset if any of them are zero sized.
88 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
89 // at the i32 element, because it is the last element at that offset. This is
90 // the right one to return, because anything after it will have a higher
91 // offset, implying that this element is non-empty.
92 return SI-&MemberOffsets[0];
95 //===----------------------------------------------------------------------===//
96 // TargetAlignElem, TargetAlign support
97 //===----------------------------------------------------------------------===//
100 TargetAlignElem::get(AlignTypeEnum align_type, unsigned abi_align,
101 unsigned pref_align, uint32_t bit_width) {
102 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
103 TargetAlignElem retval;
104 retval.AlignType = align_type;
105 retval.ABIAlign = abi_align;
106 retval.PrefAlign = pref_align;
107 retval.TypeBitWidth = bit_width;
112 TargetAlignElem::operator==(const TargetAlignElem &rhs) const {
113 return (AlignType == rhs.AlignType
114 && ABIAlign == rhs.ABIAlign
115 && PrefAlign == rhs.PrefAlign
116 && TypeBitWidth == rhs.TypeBitWidth);
119 const TargetAlignElem TargetData::InvalidAlignmentElem =
120 TargetAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
122 //===----------------------------------------------------------------------===//
123 // TargetData Class Implementation
124 //===----------------------------------------------------------------------===//
126 /// getInt - Get an integer ignoring errors.
127 static unsigned getInt(StringRef R) {
129 R.getAsInteger(10, Result);
133 void TargetData::init(StringRef Desc) {
135 LittleEndian = false;
138 PointerPrefAlign = PointerABIAlign;
140 // Default alignments
141 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
142 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
143 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
144 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
145 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
146 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
147 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
148 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32, v1i64, ...
149 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
150 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct
152 while (!Desc.empty()) {
153 std::pair<StringRef, StringRef> Split = Desc.split('-');
154 StringRef Token = Split.first;
160 Split = Token.split(':');
161 StringRef Specifier = Split.first;
162 Token = Split.second;
164 assert(!Specifier.empty() && "Can't be empty here");
166 switch (Specifier[0]) {
168 LittleEndian = false;
174 Split = Token.split(':');
175 PointerMemSize = getInt(Split.first) / 8;
176 Split = Split.second.split(':');
177 PointerABIAlign = getInt(Split.first) / 8;
178 Split = Split.second.split(':');
179 PointerPrefAlign = getInt(Split.first) / 8;
180 if (PointerPrefAlign == 0)
181 PointerPrefAlign = PointerABIAlign;
188 AlignTypeEnum AlignType;
189 switch (Specifier[0]) {
191 case 'i': AlignType = INTEGER_ALIGN; break;
192 case 'v': AlignType = VECTOR_ALIGN; break;
193 case 'f': AlignType = FLOAT_ALIGN; break;
194 case 'a': AlignType = AGGREGATE_ALIGN; break;
195 case 's': AlignType = STACK_ALIGN; break;
197 unsigned Size = getInt(Specifier.substr(1));
198 Split = Token.split(':');
199 unsigned ABIAlign = getInt(Split.first) / 8;
201 Split = Split.second.split(':');
202 unsigned PrefAlign = getInt(Split.first) / 8;
204 PrefAlign = ABIAlign;
205 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
208 case 'n': // Native integer types.
209 Specifier = Specifier.substr(1);
211 if (unsigned Width = getInt(Specifier))
212 LegalIntWidths.push_back(Width);
213 Split = Token.split(':');
214 Specifier = Split.first;
215 Token = Split.second;
216 } while (!Specifier.empty() || !Token.empty());
227 /// @note This has to exist, because this is a pass, but it should never be
229 TargetData::TargetData() : ImmutablePass(ID) {
230 report_fatal_error("Bad TargetData ctor used. "
231 "Tool did not specify a TargetData to use?");
234 TargetData::TargetData(const Module *M)
235 : ImmutablePass(ID) {
236 init(M->getDataLayout());
240 TargetData::setAlignment(AlignTypeEnum align_type, unsigned abi_align,
241 unsigned pref_align, uint32_t bit_width) {
242 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
243 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
244 if (Alignments[i].AlignType == align_type &&
245 Alignments[i].TypeBitWidth == bit_width) {
246 // Update the abi, preferred alignments.
247 Alignments[i].ABIAlign = abi_align;
248 Alignments[i].PrefAlign = pref_align;
253 Alignments.push_back(TargetAlignElem::get(align_type, abi_align,
254 pref_align, bit_width));
257 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
258 /// preferred if ABIInfo = false) the target wants for the specified datatype.
259 unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
260 uint32_t BitWidth, bool ABIInfo,
261 const Type *Ty) const {
262 // Check to see if we have an exact match and remember the best match we see.
263 int BestMatchIdx = -1;
265 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
266 if (Alignments[i].AlignType == AlignType &&
267 Alignments[i].TypeBitWidth == BitWidth)
268 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
270 // The best match so far depends on what we're looking for.
271 if (AlignType == INTEGER_ALIGN &&
272 Alignments[i].AlignType == INTEGER_ALIGN) {
273 // The "best match" for integers is the smallest size that is larger than
274 // the BitWidth requested.
275 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
276 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
278 // However, if there isn't one that's larger, then we must use the
279 // largest one we have (see below)
280 if (LargestInt == -1 ||
281 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
286 // Okay, we didn't find an exact solution. Fall back here depending on what
287 // is being looked for.
288 if (BestMatchIdx == -1) {
289 // If we didn't find an integer alignment, fall back on most conservative.
290 if (AlignType == INTEGER_ALIGN) {
291 BestMatchIdx = LargestInt;
293 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
295 // By default, use natural alignment for vector types. This is consistent
296 // with what clang and llvm-gcc do.
297 unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
298 Align *= cast<VectorType>(Ty)->getNumElements();
299 // If the alignment is not a power of 2, round up to the next power of 2.
300 // This happens for non-power-of-2 length vectors.
301 if (Align & (Align-1))
302 Align = llvm::NextPowerOf2(Align);
307 // Since we got a "best match" index, just return it.
308 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
309 : Alignments[BestMatchIdx].PrefAlign;
314 class StructLayoutMap : public AbstractTypeUser {
315 typedef DenseMap<const StructType*, StructLayout*> LayoutInfoTy;
316 LayoutInfoTy LayoutInfo;
318 void RemoveEntry(LayoutInfoTy::iterator I, bool WasAbstract) {
319 I->second->~StructLayout();
322 I->first->removeAbstractTypeUser(this);
327 /// refineAbstractType - The callback method invoked when an abstract type is
328 /// resolved to another type. An object must override this method to update
329 /// its internal state to reference NewType instead of OldType.
331 virtual void refineAbstractType(const DerivedType *OldTy,
333 LayoutInfoTy::iterator I = LayoutInfo.find(cast<const StructType>(OldTy));
334 assert(I != LayoutInfo.end() && "Using type but not in map?");
335 RemoveEntry(I, true);
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 LayoutInfoTy::iterator I = LayoutInfo.find(cast<const StructType>(AbsTy));
345 assert(I != LayoutInfo.end() && "Using type but not in map?");
346 RemoveEntry(I, true);
350 virtual ~StructLayoutMap() {
351 // Remove any layouts.
352 for (LayoutInfoTy::iterator
353 I = LayoutInfo.begin(), E = LayoutInfo.end(); I != E; ++I) {
354 const Type *Key = I->first;
355 StructLayout *Value = I->second;
357 if (Key->isAbstract())
358 Key->removeAbstractTypeUser(this);
360 Value->~StructLayout();
365 void InvalidateEntry(const StructType *Ty) {
366 LayoutInfoTy::iterator I = LayoutInfo.find(Ty);
367 if (I == LayoutInfo.end()) return;
368 RemoveEntry(I, Ty->isAbstract());
371 StructLayout *&operator[](const StructType *STy) {
372 return LayoutInfo[STy];
376 virtual void dump() const {}
379 } // end anonymous namespace
381 TargetData::~TargetData() {
382 delete static_cast<StructLayoutMap*>(LayoutMap);
385 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
387 LayoutMap = new StructLayoutMap();
389 StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
390 StructLayout *&SL = (*STM)[Ty];
393 // Otherwise, create the struct layout. Because it is variable length, we
394 // malloc it, then use placement new.
395 int NumElts = Ty->getNumElements();
397 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));
399 // Set SL before calling StructLayout's ctor. The ctor could cause other
400 // entries to be added to TheMap, invalidating our reference.
403 new (L) StructLayout(Ty, *this);
405 if (Ty->isAbstract())
406 Ty->addAbstractTypeUser(STM);
411 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
412 /// objects. If a TargetData object is alive when types are being refined and
413 /// removed, this method must be called whenever a StructType is removed to
414 /// avoid a dangling pointer in this cache.
415 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
416 if (!LayoutMap) return; // No cache.
418 static_cast<StructLayoutMap*>(LayoutMap)->InvalidateEntry(Ty);
421 std::string TargetData::getStringRepresentation() const {
423 raw_string_ostream OS(Result);
425 OS << (LittleEndian ? "e" : "E")
426 << "-p:" << PointerMemSize*8 << ':' << PointerABIAlign*8
427 << ':' << PointerPrefAlign*8;
428 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
429 const TargetAlignElem &AI = Alignments[i];
430 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
431 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
434 if (!LegalIntWidths.empty()) {
435 OS << "-n" << (unsigned)LegalIntWidths[0];
437 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
438 OS << ':' << (unsigned)LegalIntWidths[i];
444 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
445 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
446 switch (Ty->getTypeID()) {
447 case Type::LabelTyID:
448 case Type::PointerTyID:
449 return getPointerSizeInBits();
450 case Type::ArrayTyID: {
451 const ArrayType *ATy = cast<ArrayType>(Ty);
452 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
454 case Type::StructTyID:
455 // Get the layout annotation... which is lazily created on demand.
456 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
457 case Type::IntegerTyID:
458 return cast<IntegerType>(Ty)->getBitWidth();
461 case Type::FloatTyID:
463 case Type::DoubleTyID:
465 case Type::PPC_FP128TyID:
466 case Type::FP128TyID:
468 // In memory objects this is always aligned to a higher boundary, but
469 // only 80 bits contain information.
470 case Type::X86_FP80TyID:
472 case Type::VectorTyID:
473 return cast<VectorType>(Ty)->getBitWidth();
475 llvm_unreachable("TargetData::getTypeSizeInBits(): Unsupported type");
482 \param abi_or_pref Flag that determines which alignment is returned. true
483 returns the ABI alignment, false returns the preferred alignment.
484 \param Ty The underlying type for which alignment is determined.
486 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
487 == false) for the requested type \a Ty.
489 unsigned TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
492 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
493 switch (Ty->getTypeID()) {
494 // Early escape for the non-numeric types.
495 case Type::LabelTyID:
496 case Type::PointerTyID:
498 ? getPointerABIAlignment()
499 : getPointerPrefAlignment());
500 case Type::ArrayTyID:
501 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
503 case Type::StructTyID: {
504 // Packed structure types always have an ABI alignment of one.
505 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
508 // Get the layout annotation... which is lazily created on demand.
509 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
510 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
511 return std::max(Align, Layout->getAlignment());
513 case Type::IntegerTyID:
515 AlignType = INTEGER_ALIGN;
517 case Type::FloatTyID:
518 case Type::DoubleTyID:
519 // PPC_FP128TyID and FP128TyID have different data contents, but the
520 // same size and alignment, so they look the same here.
521 case Type::PPC_FP128TyID:
522 case Type::FP128TyID:
523 case Type::X86_FP80TyID:
524 AlignType = FLOAT_ALIGN;
526 case Type::VectorTyID:
527 AlignType = VECTOR_ALIGN;
530 llvm_unreachable("Bad type for getAlignment!!!");
534 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
538 unsigned TargetData::getABITypeAlignment(const Type *Ty) const {
539 return getAlignment(Ty, true);
542 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
543 /// an integer type of the specified bitwidth.
544 unsigned TargetData::getABIIntegerTypeAlignment(unsigned BitWidth) const {
545 return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, 0);
549 unsigned TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
550 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
551 if (Alignments[i].AlignType == STACK_ALIGN)
552 return Alignments[i].ABIAlign;
554 return getABITypeAlignment(Ty);
557 unsigned TargetData::getPrefTypeAlignment(const Type *Ty) const {
558 return getAlignment(Ty, false);
561 unsigned TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
562 unsigned Align = getPrefTypeAlignment(Ty);
563 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
564 return Log2_32(Align);
567 /// getIntPtrType - Return an unsigned integer type that is the same size or
568 /// greater to the host pointer size.
569 const IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
570 return IntegerType::get(C, getPointerSizeInBits());
574 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
575 unsigned NumIndices) const {
576 const Type *Ty = ptrTy;
577 assert(Ty->isPointerTy() && "Illegal argument for getIndexedOffset()");
580 generic_gep_type_iterator<Value* const*>
581 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
582 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
583 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
584 assert(Indices[CurIDX]->getType() ==
585 Type::getInt32Ty(ptrTy->getContext()) &&
586 "Illegal struct idx");
587 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
589 // Get structure layout information...
590 const StructLayout *Layout = getStructLayout(STy);
592 // Add in the offset, as calculated by the structure layout info...
593 Result += Layout->getElementOffset(FieldNo);
595 // Update Ty to refer to current element
596 Ty = STy->getElementType(FieldNo);
598 // Update Ty to refer to current element
599 Ty = cast<SequentialType>(Ty)->getElementType();
601 // Get the array index and the size of each array element.
602 if (int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue())
603 Result += (uint64_t)arrayIdx * getTypeAllocSize(Ty);
610 /// getPreferredAlignment - Return the preferred alignment of the specified
611 /// global. This includes an explicitly requested alignment (if the global
613 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
614 const Type *ElemType = GV->getType()->getElementType();
615 unsigned Alignment = getPrefTypeAlignment(ElemType);
616 if (GV->getAlignment() > Alignment)
617 Alignment = GV->getAlignment();
619 if (GV->hasInitializer()) {
620 if (Alignment < 16) {
621 // If the global is not external, see if it is large. If so, give it a
623 if (getTypeSizeInBits(ElemType) > 128)
624 Alignment = 16; // 16-byte alignment.
630 /// getPreferredAlignmentLog - Return the preferred alignment of the
631 /// specified global, returned in log form. This includes an explicitly
632 /// requested alignment (if the global has one).
633 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
634 return Log2_32(getPreferredAlignment(GV));