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"
28 #include "llvm/Config/config.h"
34 // Handle the Pass registration stuff necessary to use TargetData's.
36 // Register the default SparcV9 implementation...
37 RegisterPass<TargetData> X("targetdata", "Target Data Layout");
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() ?
54 1 : TD.getABITypeAlignment(Ty);
55 uint64_t TySize = ST->isPacked() ?
56 TD.getTypeStoreSize(Ty) : TD.getABITypeSize(Ty);
58 // Add padding if necessary to align the data element properly...
59 StructSize = (StructSize + TyAlign - 1)/TyAlign * TyAlign;
61 // Keep track of maximum alignment constraint
62 StructAlignment = std::max(TyAlign, StructAlignment);
64 MemberOffsets[i] = StructSize;
65 StructSize += TySize; // Consume space for this data item
68 // Empty structures have alignment of 1 byte.
69 if (StructAlignment == 0) StructAlignment = 1;
71 // Add padding to the end of the struct so that it could be put in an array
72 // and all array elements would be aligned correctly.
73 if (StructSize % StructAlignment != 0)
74 StructSize = (StructSize/StructAlignment + 1) * StructAlignment;
78 /// getElementContainingOffset - Given a valid offset into the structure,
79 /// return the structure index that contains it.
80 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
82 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
83 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
85 assert(*SI <= Offset && "upper_bound didn't work");
86 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
87 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
88 "Upper bound didn't work!");
90 // Multiple fields can have the same offset if any of them are zero sized.
91 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
92 // at the i32 element, because it is the last element at that offset. This is
93 // the right one to return, because anything after it will have a higher
94 // offset, implying that this element is non-empty.
95 return SI-&MemberOffsets[0];
98 //===----------------------------------------------------------------------===//
99 // TargetAlignElem, TargetAlign support
100 //===----------------------------------------------------------------------===//
103 TargetAlignElem::get(AlignTypeEnum align_type, unsigned char abi_align,
104 unsigned char pref_align, uint32_t bit_width) {
105 TargetAlignElem retval;
106 retval.AlignType = align_type;
107 retval.ABIAlign = abi_align;
108 retval.PrefAlign = pref_align;
109 retval.TypeBitWidth = bit_width;
114 TargetAlignElem::operator==(const TargetAlignElem &rhs) const {
115 return (AlignType == rhs.AlignType
116 && ABIAlign == rhs.ABIAlign
117 && PrefAlign == rhs.PrefAlign
118 && TypeBitWidth == rhs.TypeBitWidth);
122 TargetAlignElem::dump(std::ostream &os) const {
123 return os << AlignType
125 << ":" << (int) (ABIAlign * 8)
126 << ":" << (int) (PrefAlign * 8);
129 const TargetAlignElem TargetData::InvalidAlignmentElem =
130 TargetAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
132 //===----------------------------------------------------------------------===//
133 // TargetData Class Implementation
134 //===----------------------------------------------------------------------===//
136 bool TargetData::hostIsLittleEndian() const {
145 A TargetDescription string consists of a sequence of hyphen-delimited
146 specifiers for target endianness, pointer size and alignments, and various
147 primitive type sizes and alignments. A typical string looks something like:
149 "E-p:32:32:32-i1:8:8-i8:8:8-i32:32:32-i64:32:64-f32:32:32-f64:32:64"
151 (note: this string is not fully specified and is only an example.)
153 Alignments come in two flavors: ABI and preferred. ABI alignment (abi_align,
154 below) dictates how a type will be aligned within an aggregate and when used
155 as an argument. Preferred alignment (pref_align, below) determines a type's
156 alignment when emitted as a global.
158 Specifier string details:
160 <i>[E|e]</i>: Endianness. "E" specifies a big-endian target data model, "e"
161 specifies a little-endian target data model.
163 <i>p:@verbatim<size>:<abi_align>:<pref_align>@endverbatim</i>: Pointer size,
164 ABI and preferred alignment.
166 <i>@verbatim<type><size>:<abi_align>:<pref_align>@endverbatim</i>: Numeric type alignment. Type is
167 one of <i>i|f|v|a</i>, corresponding to integer, floating point, vector (aka
168 packed) or aggregate. Size indicates the size, e.g., 32 or 64 bits.
170 The default string, fully specified is:
172 "E-p:64:64:64-a0:0:0-f32:32:32-f64:0:64"
173 "-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:0:64"
174 "-v64:64:64-v128:128:128"
176 Note that in the case of aggregates, 0 is the default ABI and preferred
177 alignment. This is a special case, where the aggregate's computed worst-case
178 alignment will be used.
180 void TargetData::init(const std::string &TargetDescription) {
181 std::string temp = TargetDescription;
183 LittleEndian = false;
186 PointerPrefAlign = PointerABIAlign;
188 // Default alignments
189 setAlignment(INTEGER_ALIGN, 1, 1, 1); // Bool
190 setAlignment(INTEGER_ALIGN, 1, 1, 8); // Byte
191 setAlignment(INTEGER_ALIGN, 2, 2, 16); // short
192 setAlignment(INTEGER_ALIGN, 4, 4, 32); // int
193 setAlignment(INTEGER_ALIGN, 4, 8, 64); // long
194 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
195 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
196 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32
197 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
198 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct, union, class, ...
200 while (!temp.empty()) {
201 std::string token = getToken(temp, "-");
202 std::string arg0 = getToken(token, ":");
203 const char *p = arg0.c_str();
206 LittleEndian = false;
212 PointerMemSize = atoi(getToken(token,":").c_str()) / 8;
213 PointerABIAlign = atoi(getToken(token,":").c_str()) / 8;
214 PointerPrefAlign = atoi(getToken(token,":").c_str()) / 8;
215 if (PointerPrefAlign == 0)
216 PointerPrefAlign = PointerABIAlign;
223 AlignTypeEnum align_type = STACK_ALIGN; // Dummy init, silence warning
225 case 'i': align_type = INTEGER_ALIGN; break;
226 case 'v': align_type = VECTOR_ALIGN; break;
227 case 'f': align_type = FLOAT_ALIGN; break;
228 case 'a': align_type = AGGREGATE_ALIGN; break;
229 case 's': align_type = STACK_ALIGN; break;
231 uint32_t size = (uint32_t) atoi(++p);
232 unsigned char abi_align = atoi(getToken(token, ":").c_str()) / 8;
233 unsigned char pref_align = atoi(getToken(token, ":").c_str()) / 8;
235 pref_align = abi_align;
236 setAlignment(align_type, abi_align, pref_align, size);
245 TargetData::TargetData(const Module *M)
246 : ImmutablePass((intptr_t)&ID) {
247 init(M->getDataLayout());
251 TargetData::setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
252 unsigned char pref_align, uint32_t bit_width) {
253 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
254 if (Alignments[i].AlignType == align_type &&
255 Alignments[i].TypeBitWidth == bit_width) {
256 // Update the abi, preferred alignments.
257 Alignments[i].ABIAlign = abi_align;
258 Alignments[i].PrefAlign = pref_align;
263 Alignments.push_back(TargetAlignElem::get(align_type, abi_align,
264 pref_align, bit_width));
267 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
268 /// preferred if ABIInfo = false) the target wants for the specified datatype.
269 unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
270 uint32_t BitWidth, bool ABIInfo) 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) {
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].AlignType == VECTOR_ALIGN &&
285 Alignments[i].TypeBitWidth < BitWidth) {
286 // Verify that we pick the biggest of the fallbacks.
287 if (BestMatchIdx == -1 ||
288 Alignments[BestMatchIdx].TypeBitWidth < BitWidth)
291 } else if (AlignType == INTEGER_ALIGN &&
292 Alignments[i].AlignType == INTEGER_ALIGN) {
293 // The "best match" for integers is the smallest size that is larger than
294 // the BitWidth requested.
295 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
296 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
298 // However, if there isn't one that's larger, then we must use the
299 // largest one we have (see below)
300 if (LargestInt == -1 ||
301 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
306 // For integers, if we didn't find a best match, use the largest one found.
307 if (BestMatchIdx == -1)
308 BestMatchIdx = LargestInt;
310 // Okay, we didn't find an exact solution. Fall back here depending on what
311 // is being looked for.
312 assert(BestMatchIdx != -1 && "Didn't find alignment info for this datatype!");
314 // Since we got a "best match" index, just return it.
315 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
316 : Alignments[BestMatchIdx].PrefAlign;
319 /// LayoutInfo - The lazy cache of structure layout information maintained by
320 /// TargetData. Note that the struct types must have been free'd before
321 /// llvm_shutdown is called (and thus this is deallocated) because all the
322 /// targets with cached elements should have been destroyed.
324 typedef std::pair<const TargetData*,const StructType*> LayoutKey;
326 struct DenseMapLayoutKeyInfo {
327 static inline LayoutKey getEmptyKey() { return LayoutKey(0, 0); }
328 static inline LayoutKey getTombstoneKey() {
329 return LayoutKey((TargetData*)(intptr_t)-1, 0);
331 static unsigned getHashValue(const LayoutKey &Val) {
332 return DenseMapInfo<void*>::getHashValue(Val.first) ^
333 DenseMapInfo<void*>::getHashValue(Val.second);
335 static bool isEqual(const LayoutKey &LHS, const LayoutKey &RHS) {
339 static bool isPod() { return true; }
342 typedef DenseMap<LayoutKey, StructLayout*, DenseMapLayoutKeyInfo> LayoutInfoTy;
343 static ManagedStatic<LayoutInfoTy> LayoutInfo;
346 TargetData::~TargetData() {
347 if (LayoutInfo.isConstructed()) {
348 // Remove any layouts for this TD.
349 LayoutInfoTy &TheMap = *LayoutInfo;
350 for (LayoutInfoTy::iterator I = TheMap.begin(), E = TheMap.end();
352 if (I->first.first == this) {
353 I->second->~StructLayout();
363 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
364 LayoutInfoTy &TheMap = *LayoutInfo;
366 StructLayout *&SL = TheMap[LayoutKey(this, Ty)];
369 // Otherwise, create the struct layout. Because it is variable length, we
370 // malloc it, then use placement new.
371 int NumElts = Ty->getNumElements();
373 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1)*sizeof(uint64_t));
375 // Set SL before calling StructLayout's ctor. The ctor could cause other
376 // entries to be added to TheMap, invalidating our reference.
379 new (L) StructLayout(Ty, *this);
383 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
384 /// objects. If a TargetData object is alive when types are being refined and
385 /// removed, this method must be called whenever a StructType is removed to
386 /// avoid a dangling pointer in this cache.
387 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
388 if (!LayoutInfo.isConstructed()) return; // No cache.
390 LayoutInfoTy::iterator I = LayoutInfo->find(LayoutKey(this, Ty));
391 if (I != LayoutInfo->end()) {
392 I->second->~StructLayout();
394 LayoutInfo->erase(I);
399 std::string TargetData::getStringRepresentation() const {
401 repr.append(LittleEndian ? "e" : "E");
402 repr.append("-p:").append(itostr((int64_t) (PointerMemSize * 8))).
403 append(":").append(itostr((int64_t) (PointerABIAlign * 8))).
404 append(":").append(itostr((int64_t) (PointerPrefAlign * 8)));
405 for (align_const_iterator I = Alignments.begin();
406 I != Alignments.end();
408 repr.append("-").append(1, (char) I->AlignType).
409 append(utostr((int64_t) I->TypeBitWidth)).
410 append(":").append(utostr((uint64_t) (I->ABIAlign * 8))).
411 append(":").append(utostr((uint64_t) (I->PrefAlign * 8)));
417 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
418 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
419 switch (Ty->getTypeID()) {
420 case Type::LabelTyID:
421 case Type::PointerTyID:
422 return getPointerSizeInBits();
423 case Type::ArrayTyID: {
424 const ArrayType *ATy = cast<ArrayType>(Ty);
425 return getABITypeSizeInBits(ATy->getElementType())*ATy->getNumElements();
427 case Type::StructTyID: {
428 // Get the layout annotation... which is lazily created on demand.
429 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
430 return Layout->getSizeInBits();
432 case Type::IntegerTyID:
433 return cast<IntegerType>(Ty)->getBitWidth();
436 case Type::FloatTyID:
438 case Type::DoubleTyID:
440 case Type::PPC_FP128TyID:
441 case Type::FP128TyID:
443 // In memory objects this is always aligned to a higher boundary, but
444 // only 80 bits contain information.
445 case Type::X86_FP80TyID:
447 case Type::VectorTyID: {
448 const VectorType *PTy = cast<VectorType>(Ty);
449 return PTy->getBitWidth();
452 assert(0 && "TargetData::getTypeSizeInBits(): Unsupported type");
459 \param abi_or_pref Flag that determines which alignment is returned. true
460 returns the ABI alignment, false returns the preferred alignment.
461 \param Ty The underlying type for which alignment is determined.
463 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
464 == false) for the requested type \a Ty.
466 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
469 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
470 switch (Ty->getTypeID()) {
471 /* Early escape for the non-numeric types */
472 case Type::LabelTyID:
473 case Type::PointerTyID:
475 ? getPointerABIAlignment()
476 : getPointerPrefAlignment());
477 case Type::ArrayTyID:
478 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
480 case Type::StructTyID: {
481 // Packed structure types always have an ABI alignment of one.
482 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
485 // Get the layout annotation... which is lazily created on demand.
486 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
487 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref);
488 return std::max(Align, (unsigned)Layout->getAlignment());
490 case Type::IntegerTyID:
492 AlignType = INTEGER_ALIGN;
494 case Type::FloatTyID:
495 case Type::DoubleTyID:
496 // PPC_FP128TyID and FP128TyID have different data contents, but the
497 // same size and alignment, so they look the same here.
498 case Type::PPC_FP128TyID:
499 case Type::FP128TyID:
500 case Type::X86_FP80TyID:
501 AlignType = FLOAT_ALIGN;
503 case Type::VectorTyID: {
504 const VectorType *VTy = cast<VectorType>(Ty);
505 // Degenerate vectors are assumed to be scalar-ized
506 if (VTy->getNumElements() == 1)
507 return getAlignment(VTy->getElementType(), abi_or_pref);
509 AlignType = VECTOR_ALIGN;
513 assert(0 && "Bad type for getAlignment!!!");
517 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
521 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
522 return getAlignment(Ty, true);
525 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
526 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
527 if (Alignments[i].AlignType == STACK_ALIGN)
528 return Alignments[i].ABIAlign;
530 return getABITypeAlignment(Ty);
533 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
534 return getAlignment(Ty, false);
537 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
538 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
539 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
540 return Log2_32(Align);
543 /// getIntPtrType - Return an unsigned integer type that is the same size or
544 /// greater to the host pointer size.
545 const Type *TargetData::getIntPtrType() const {
546 return IntegerType::get(getPointerSizeInBits());
550 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
551 unsigned NumIndices) const {
552 const Type *Ty = ptrTy;
553 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
556 generic_gep_type_iterator<Value* const*>
557 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
558 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
559 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
560 assert(Indices[CurIDX]->getType() == Type::Int32Ty &&
561 "Illegal struct idx");
562 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
564 // Get structure layout information...
565 const StructLayout *Layout = getStructLayout(STy);
567 // Add in the offset, as calculated by the structure layout info...
568 Result += Layout->getElementOffset(FieldNo);
570 // Update Ty to refer to current element
571 Ty = STy->getElementType(FieldNo);
573 // Update Ty to refer to current element
574 Ty = cast<SequentialType>(Ty)->getElementType();
576 // Get the array index and the size of each array element.
577 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
578 Result += arrayIdx * (int64_t)getABITypeSize(Ty);
585 /// getPreferredAlignmentLog - Return the preferred alignment of the
586 /// specified global, returned in log form. This includes an explicitly
587 /// requested alignment (if the global has one).
588 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
589 const Type *ElemType = GV->getType()->getElementType();
590 unsigned Alignment = getPreferredTypeAlignmentShift(ElemType);
591 if (GV->getAlignment() > (1U << Alignment))
592 Alignment = Log2_32(GV->getAlignment());
594 if (GV->hasInitializer()) {
596 // If the global is not external, see if it is large. If so, give it a
598 if (getTypeSizeInBits(ElemType) > 128)
599 Alignment = 4; // 16-byte alignment.