1 //===-- TargetData.cpp - Data size & alignment routines --------------------==//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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/Module.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Constants.h"
23 #include "llvm/Support/GetElementPtrTypeIterator.h"
24 #include "llvm/Support/MathExtras.h"
25 #include "llvm/Support/ManagedStatic.h"
26 #include "llvm/ADT/DenseMap.h"
27 #include "llvm/ADT/StringExtras.h"
33 // Handle the Pass registration stuff necessary to use TargetData's.
35 // Register the default SparcV9 implementation...
36 RegisterPass<TargetData> X("targetdata", "Target Data Layout");
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() ?
53 1 : TD.getABITypeAlignment(Ty);
54 uint64_t TySize = ST->isPacked() ?
55 TD.getTypeStoreSize(Ty) : TD.getABITypeSize(Ty);
57 // Add padding if necessary to align the data element properly...
58 StructSize = (StructSize + TyAlign - 1)/TyAlign * TyAlign;
60 // Keep track of maximum alignment constraint
61 StructAlignment = std::max(TyAlign, StructAlignment);
63 MemberOffsets[i] = StructSize;
64 StructSize += TySize; // Consume space for this data item
67 // Empty structures have alignment of 1 byte.
68 if (StructAlignment == 0) StructAlignment = 1;
70 // Add padding to the end of the struct so that it could be put in an array
71 // and all array elements would be aligned correctly.
72 if (StructSize % StructAlignment != 0)
73 StructSize = (StructSize/StructAlignment + 1) * StructAlignment;
77 /// getElementContainingOffset - Given a valid offset into the structure,
78 /// return the structure index that contains it.
79 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
81 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
82 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
84 assert(*SI <= Offset && "upper_bound didn't work");
85 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
86 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
87 "Upper bound didn't work!");
89 // Multiple fields can have the same offset if any of them are zero sized.
90 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
91 // at the i32 element, because it is the last element at that offset. This is
92 // the right one to return, because anything after it will have a higher
93 // offset, implying that this element is non-empty.
94 return SI-&MemberOffsets[0];
97 //===----------------------------------------------------------------------===//
98 // TargetAlignElem, TargetAlign support
99 //===----------------------------------------------------------------------===//
102 TargetAlignElem::get(AlignTypeEnum align_type, unsigned char abi_align,
103 unsigned char pref_align, uint32_t bit_width) {
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 //===----------------------------------------------------------------------===//
136 A TargetDescription string consists of a sequence of hyphen-delimited
137 specifiers for target endianness, pointer size and alignments, and various
138 primitive type sizes and alignments. A typical string looks something like:
140 "E-p:32:32:32-i1:8:8-i8:8:8-i32:32:32-i64:32:64-f32:32:32-f64:32:64"
142 (note: this string is not fully specified and is only an example.)
144 Alignments come in two flavors: ABI and preferred. ABI alignment (abi_align,
145 below) dictates how a type will be aligned within an aggregate and when used
146 as an argument. Preferred alignment (pref_align, below) determines a type's
147 alignment when emitted as a global.
149 Specifier string details:
151 <i>[E|e]</i>: Endianness. "E" specifies a big-endian target data model, "e"
152 specifies a little-endian target data model.
154 <i>p:@verbatim<size>:<abi_align>:<pref_align>@endverbatim</i>: Pointer size,
155 ABI and preferred alignment.
157 <i>@verbatim<type><size>:<abi_align>:<pref_align>@endverbatim</i>: Numeric type alignment. Type is
158 one of <i>i|f|v|a</i>, corresponding to integer, floating point, vector (aka
159 packed) or aggregate. Size indicates the size, e.g., 32 or 64 bits.
161 The default string, fully specified is:
163 "E-p:64:64:64-a0:0:0-f32:32:32-f64:0:64"
164 "-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:0:64"
165 "-v64:64:64-v128:128:128"
167 Note that in the case of aggregates, 0 is the default ABI and preferred
168 alignment. This is a special case, where the aggregate's computed worst-case
169 alignment will be used.
171 void TargetData::init(const std::string &TargetDescription) {
172 std::string temp = TargetDescription;
174 LittleEndian = false;
177 PointerPrefAlign = PointerABIAlign;
179 // Default alignments
180 setAlignment(INTEGER_ALIGN, 1, 1, 1); // Bool
181 setAlignment(INTEGER_ALIGN, 1, 1, 8); // Byte
182 setAlignment(INTEGER_ALIGN, 2, 2, 16); // short
183 setAlignment(INTEGER_ALIGN, 4, 4, 32); // int
184 setAlignment(INTEGER_ALIGN, 4, 8, 64); // long
185 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
186 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
187 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32
188 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
189 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct, union, class, ...
191 while (!temp.empty()) {
192 std::string token = getToken(temp, "-");
193 std::string arg0 = getToken(token, ":");
194 const char *p = arg0.c_str();
197 LittleEndian = false;
203 PointerMemSize = atoi(getToken(token,":").c_str()) / 8;
204 PointerABIAlign = atoi(getToken(token,":").c_str()) / 8;
205 PointerPrefAlign = atoi(getToken(token,":").c_str()) / 8;
206 if (PointerPrefAlign == 0)
207 PointerPrefAlign = PointerABIAlign;
214 AlignTypeEnum align_type = STACK_ALIGN; // Dummy init, silence warning
216 case 'i': align_type = INTEGER_ALIGN; break;
217 case 'v': align_type = VECTOR_ALIGN; break;
218 case 'f': align_type = FLOAT_ALIGN; break;
219 case 'a': align_type = AGGREGATE_ALIGN; break;
220 case 's': align_type = STACK_ALIGN; break;
222 uint32_t size = (uint32_t) atoi(++p);
223 unsigned char abi_align = atoi(getToken(token, ":").c_str()) / 8;
224 unsigned char pref_align = atoi(getToken(token, ":").c_str()) / 8;
226 pref_align = abi_align;
227 setAlignment(align_type, abi_align, pref_align, size);
236 TargetData::TargetData(const Module *M)
237 : ImmutablePass((intptr_t)&ID) {
238 init(M->getDataLayout());
242 TargetData::setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
243 unsigned char pref_align, uint32_t bit_width) {
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) 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 == VECTOR_ALIGN && Alignments[i].AlignType == VECTOR_ALIGN) {
272 // If this is a specification for a smaller vector type, we will fall back
273 // to it. This happens because <128 x double> can be implemented in terms
274 // of 64 <2 x double>.
275 if (Alignments[i].TypeBitWidth < BitWidth) {
276 // Verify that we pick the biggest of the fallbacks.
277 if (BestMatchIdx == -1 ||
278 Alignments[BestMatchIdx].TypeBitWidth < Alignments[i].TypeBitWidth)
281 } else if (AlignType == INTEGER_ALIGN &&
282 Alignments[i].AlignType == INTEGER_ALIGN) {
283 // The "best match" for integers is the smallest size that is larger than
284 // the BitWidth requested.
285 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
286 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
288 // However, if there isn't one that's larger, then we must use the
289 // largest one we have (see below)
290 if (LargestInt == -1 ||
291 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
296 // For integers, if we didn't find a best match, use the largest one found.
297 if (BestMatchIdx == -1)
298 BestMatchIdx = LargestInt;
300 // Okay, we didn't find an exact solution. Fall back here depending on what
301 // is being looked for.
302 assert(BestMatchIdx != -1 && "Didn't find alignment info for this datatype!");
304 // Since we got a "best match" index, just return it.
305 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
306 : Alignments[BestMatchIdx].PrefAlign;
309 /// LayoutInfo - The lazy cache of structure layout information maintained by
310 /// TargetData. Note that the struct types must have been free'd before
311 /// llvm_shutdown is called (and thus this is deallocated) because all the
312 /// targets with cached elements should have been destroyed.
314 typedef std::pair<const TargetData*,const StructType*> LayoutKey;
316 struct DenseMapLayoutKeyInfo {
317 static inline LayoutKey getEmptyKey() { return LayoutKey(0, 0); }
318 static inline LayoutKey getTombstoneKey() {
319 return LayoutKey((TargetData*)(intptr_t)-1, 0);
321 static unsigned getHashValue(const LayoutKey &Val) {
322 return DenseMapInfo<void*>::getHashValue(Val.first) ^
323 DenseMapInfo<void*>::getHashValue(Val.second);
325 static bool isEqual(const LayoutKey &LHS, const LayoutKey &RHS) {
329 static bool isPod() { return true; }
332 typedef DenseMap<LayoutKey, StructLayout*, DenseMapLayoutKeyInfo> LayoutInfoTy;
333 static ManagedStatic<LayoutInfoTy> LayoutInfo;
336 TargetData::~TargetData() {
337 if (LayoutInfo.isConstructed()) {
338 // Remove any layouts for this TD.
339 LayoutInfoTy &TheMap = *LayoutInfo;
340 for (LayoutInfoTy::iterator I = TheMap.begin(), E = TheMap.end();
342 if (I->first.first == this) {
343 I->second->~StructLayout();
353 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
354 LayoutInfoTy &TheMap = *LayoutInfo;
356 StructLayout *&SL = TheMap[LayoutKey(this, Ty)];
359 // Otherwise, create the struct layout. Because it is variable length, we
360 // malloc it, then use placement new.
361 int NumElts = Ty->getNumElements();
363 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1)*sizeof(uint64_t));
365 // Set SL before calling StructLayout's ctor. The ctor could cause other
366 // entries to be added to TheMap, invalidating our reference.
369 new (L) StructLayout(Ty, *this);
373 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
374 /// objects. If a TargetData object is alive when types are being refined and
375 /// removed, this method must be called whenever a StructType is removed to
376 /// avoid a dangling pointer in this cache.
377 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
378 if (!LayoutInfo.isConstructed()) return; // No cache.
380 LayoutInfoTy::iterator I = LayoutInfo->find(LayoutKey(this, Ty));
381 if (I != LayoutInfo->end()) {
382 I->second->~StructLayout();
384 LayoutInfo->erase(I);
389 std::string TargetData::getStringRepresentation() const {
391 repr.append(LittleEndian ? "e" : "E");
392 repr.append("-p:").append(itostr((int64_t) (PointerMemSize * 8))).
393 append(":").append(itostr((int64_t) (PointerABIAlign * 8))).
394 append(":").append(itostr((int64_t) (PointerPrefAlign * 8)));
395 for (align_const_iterator I = Alignments.begin();
396 I != Alignments.end();
398 repr.append("-").append(1, (char) I->AlignType).
399 append(utostr((int64_t) I->TypeBitWidth)).
400 append(":").append(utostr((uint64_t) (I->ABIAlign * 8))).
401 append(":").append(utostr((uint64_t) (I->PrefAlign * 8)));
407 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
408 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
409 switch (Ty->getTypeID()) {
410 case Type::LabelTyID:
411 case Type::PointerTyID:
412 return getPointerSizeInBits();
413 case Type::ArrayTyID: {
414 const ArrayType *ATy = cast<ArrayType>(Ty);
415 return getABITypeSizeInBits(ATy->getElementType())*ATy->getNumElements();
417 case Type::StructTyID: {
418 // Get the layout annotation... which is lazily created on demand.
419 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
420 return Layout->getSizeInBits();
422 case Type::IntegerTyID:
423 return cast<IntegerType>(Ty)->getBitWidth();
426 case Type::FloatTyID:
428 case Type::DoubleTyID:
430 case Type::PPC_FP128TyID:
431 case Type::FP128TyID:
433 // In memory objects this is always aligned to a higher boundary, but
434 // only 80 bits contain information.
435 case Type::X86_FP80TyID:
437 case Type::VectorTyID: {
438 const VectorType *PTy = cast<VectorType>(Ty);
439 return PTy->getBitWidth();
442 assert(0 && "TargetData::getTypeSizeInBits(): Unsupported type");
449 \param abi_or_pref Flag that determines which alignment is returned. true
450 returns the ABI alignment, false returns the preferred alignment.
451 \param Ty The underlying type for which alignment is determined.
453 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
454 == false) for the requested type \a Ty.
456 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
459 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
460 switch (Ty->getTypeID()) {
461 /* Early escape for the non-numeric types */
462 case Type::LabelTyID:
463 case Type::PointerTyID:
465 ? getPointerABIAlignment()
466 : getPointerPrefAlignment());
467 case Type::ArrayTyID:
468 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
470 case Type::StructTyID: {
471 // Packed structure types always have an ABI alignment of one.
472 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
475 // Get the layout annotation... which is lazily created on demand.
476 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
477 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref);
478 return std::max(Align, (unsigned)Layout->getAlignment());
480 case Type::IntegerTyID:
482 AlignType = INTEGER_ALIGN;
484 case Type::FloatTyID:
485 case Type::DoubleTyID:
486 // PPC_FP128TyID and FP128TyID have different data contents, but the
487 // same size and alignment, so they look the same here.
488 case Type::PPC_FP128TyID:
489 case Type::FP128TyID:
490 case Type::X86_FP80TyID:
491 AlignType = FLOAT_ALIGN;
493 case Type::VectorTyID: {
494 const VectorType *VTy = cast<VectorType>(Ty);
495 // Degenerate vectors are assumed to be scalar-ized
496 if (VTy->getNumElements() == 1)
497 return getAlignment(VTy->getElementType(), abi_or_pref);
499 AlignType = VECTOR_ALIGN;
503 assert(0 && "Bad type for getAlignment!!!");
507 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
511 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
512 return getAlignment(Ty, true);
515 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
516 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
517 if (Alignments[i].AlignType == STACK_ALIGN)
518 return Alignments[i].ABIAlign;
520 return getABITypeAlignment(Ty);
523 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
524 return getAlignment(Ty, false);
527 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
528 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
529 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
530 return Log2_32(Align);
533 /// getIntPtrType - Return an unsigned integer type that is the same size or
534 /// greater to the host pointer size.
535 const Type *TargetData::getIntPtrType() const {
536 return IntegerType::get(getPointerSizeInBits());
540 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
541 unsigned NumIndices) const {
542 const Type *Ty = ptrTy;
543 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
546 generic_gep_type_iterator<Value* const*>
547 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
548 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
549 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
550 assert(Indices[CurIDX]->getType() == Type::Int32Ty &&
551 "Illegal struct idx");
552 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
554 // Get structure layout information...
555 const StructLayout *Layout = getStructLayout(STy);
557 // Add in the offset, as calculated by the structure layout info...
558 Result += Layout->getElementOffset(FieldNo);
560 // Update Ty to refer to current element
561 Ty = STy->getElementType(FieldNo);
563 // Update Ty to refer to current element
564 Ty = cast<SequentialType>(Ty)->getElementType();
566 // Get the array index and the size of each array element.
567 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
568 Result += arrayIdx * (int64_t)getABITypeSize(Ty);
575 /// getPreferredAlignmentLog - Return the preferred alignment of the
576 /// specified global, returned in log form. This includes an explicitly
577 /// requested alignment (if the global has one).
578 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
579 const Type *ElemType = GV->getType()->getElementType();
580 unsigned Alignment = getPreferredTypeAlignmentShift(ElemType);
581 if (GV->getAlignment() > (1U << Alignment))
582 Alignment = Log2_32(GV->getAlignment());
584 if (GV->hasInitializer()) {
586 // If the global is not external, see if it is large. If so, give it a
588 if (getTypeSizeInBits(ElemType) > 128)
589 Alignment = 4; // 16-byte alignment.