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");
39 //===----------------------------------------------------------------------===//
40 // Support for StructLayout
41 //===----------------------------------------------------------------------===//
43 StructLayout::StructLayout(const StructType *ST, const TargetData &TD) {
46 NumElements = ST->getNumElements();
48 // Loop over each of the elements, placing them in memory...
49 for (unsigned i = 0, e = NumElements; i != e; ++i) {
50 const Type *Ty = ST->getElementType(i);
53 TyAlign = (ST->isPacked() ? 1 : TD.getABITypeAlignment(Ty));
54 TySize = TD.getTypeSize(Ty);
56 // Add padding if necessary to make the data element aligned properly...
57 if (StructSize % TyAlign != 0)
58 StructSize = (StructSize/TyAlign + 1) * TyAlign; // Add padding...
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!");
88 return SI-&MemberOffsets[0];
91 //===----------------------------------------------------------------------===//
92 // TargetAlignElem, TargetAlign support
93 //===----------------------------------------------------------------------===//
96 TargetAlignElem::get(AlignTypeEnum align_type, unsigned char abi_align,
97 unsigned char pref_align, short bit_width) {
98 TargetAlignElem retval;
99 retval.AlignType = align_type;
100 retval.ABIAlign = abi_align;
101 retval.PrefAlign = pref_align;
102 retval.TypeBitWidth = bit_width;
107 TargetAlignElem::operator==(const TargetAlignElem &rhs) const {
108 return (AlignType == rhs.AlignType
109 && ABIAlign == rhs.ABIAlign
110 && PrefAlign == rhs.PrefAlign
111 && TypeBitWidth == rhs.TypeBitWidth);
115 TargetAlignElem::dump(std::ostream &os) const {
116 return os << AlignType
118 << ":" << (int) (ABIAlign * 8)
119 << ":" << (int) (PrefAlign * 8);
122 const TargetAlignElem TargetData::InvalidAlignmentElem =
123 TargetAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
125 //===----------------------------------------------------------------------===//
126 // TargetData Class Implementation
127 //===----------------------------------------------------------------------===//
130 A TargetDescription string consists of a sequence of hyphen-delimited
131 specifiers for target endianness, pointer size and alignments, and various
132 primitive type sizes and alignments. A typical string looks something like:
134 "E-p:32:32:32-i1:8:8-i8:8:8-i32:32:32-i64:32:64-f32:32:32-f64:32:64"
136 (note: this string is not fully specified and is only an example.)
138 Alignments come in two flavors: ABI and preferred. ABI alignment (abi_align,
139 below) dictates how a type will be aligned within an aggregate and when used
140 as an argument. Preferred alignment (pref_align, below) determines a type's
141 alignment when emitted as a global.
143 Specifier string details:
145 <i>[E|e]</i>: Endianness. "E" specifies a big-endian target data model, "e"
146 specifies a little-endian target data model.
148 <i>p:<size>:<abi_align>:<pref_align></i>: Pointer size, ABI and preferred
151 <i><type><size>:<abi_align>:<pref_align></i>: Numeric type alignment. Type is
152 one of <i>i|f|v|a</i>, corresponding to integer, floating point, vector (aka
153 packed) or aggregate. Size indicates the size, e.g., 32 or 64 bits.
155 The default string, fully specified is:
157 "E-p:64:64:64-a0:0:0-f32:32:32-f64:0:64"
158 "-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:0:64"
159 "-v64:64:64-v128:128:128"
161 Note that in the case of aggregates, 0 is the default ABI and preferred
162 alignment. This is a special case, where the aggregate's computed worst-case
163 alignment will be used.
165 void TargetData::init(const std::string &TargetDescription) {
166 std::string temp = TargetDescription;
168 LittleEndian = false;
171 PointerPrefAlign = PointerABIAlign;
173 // Default alignments
174 setAlignment(INTEGER_ALIGN, 1, 1, 1); // Bool
175 setAlignment(INTEGER_ALIGN, 1, 1, 8); // Byte
176 setAlignment(INTEGER_ALIGN, 2, 2, 16); // short
177 setAlignment(INTEGER_ALIGN, 4, 4, 32); // int
178 setAlignment(INTEGER_ALIGN, 4, 8, 64); // long
179 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
180 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
181 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32
182 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
183 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct, union, class, ...
185 while (!temp.empty()) {
186 std::string token = getToken(temp, "-");
188 std::string arg0 = getToken(token, ":");
189 const char *p = arg0.c_str();
190 AlignTypeEnum align_type;
192 unsigned char abi_align;
193 unsigned char pref_align;
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;
213 align_type = (*p == 'i' ? INTEGER_ALIGN :
214 (*p == 'f' ? FLOAT_ALIGN :
215 (*p == 'v' ? VECTOR_ALIGN : AGGREGATE_ALIGN)));
216 size = (short) atoi(++p);
217 abi_align = atoi(getToken(token, ":").c_str()) / 8;
218 pref_align = atoi(getToken(token, ":").c_str()) / 8;
220 pref_align = abi_align;
221 setAlignment(align_type, abi_align, pref_align, size);
230 TargetData::TargetData(const Module *M) {
231 init(M->getDataLayout());
235 TargetData::setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
236 unsigned char pref_align, short bit_width) {
237 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
238 if (Alignments[i].AlignType == align_type &&
239 Alignments[i].TypeBitWidth == bit_width) {
240 // Update the abi, preferred alignments.
241 Alignments[i].ABIAlign = abi_align;
242 Alignments[i].PrefAlign = pref_align;
247 Alignments.push_back(TargetAlignElem::get(align_type, abi_align,
248 pref_align, bit_width));
251 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
252 /// preferred if ABIInfo = false) the target wants for the specified datatype.
253 unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType, short BitWidth,
254 bool ABIInfo) const {
255 // Check to see if we have an exact match and remember the best match we see.
256 int BestMatchIdx = -1;
257 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
258 if (Alignments[i].AlignType == AlignType &&
259 Alignments[i].TypeBitWidth == BitWidth)
260 return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;
262 // The best match so far depends on what we're looking for.
263 if (AlignType == VECTOR_ALIGN) {
264 // If this is a specification for a smaller vector type, we will fall back
265 // to it. This happens because <128 x double> can be implemented in terms
266 // of 64 <2 x double>.
267 if (Alignments[i].AlignType == VECTOR_ALIGN &&
268 Alignments[i].TypeBitWidth < BitWidth) {
269 // Verify that we pick the biggest of the fallbacks.
270 if (BestMatchIdx == -1 ||
271 Alignments[BestMatchIdx].TypeBitWidth < BitWidth)
276 // FIXME: handle things like i37.
279 // Okay, we didn't find an exact solution. Fall back here depending on what
280 // is being looked for.
281 assert(BestMatchIdx != -1 && "Didn't find alignment info for this datatype!");
282 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
283 : Alignments[BestMatchIdx].PrefAlign;
286 /// LayoutInfo - The lazy cache of structure layout information maintained by
287 /// TargetData. Note that the struct types must have been free'd before
288 /// llvm_shutdown is called (and thus this is deallocated) because all the
289 /// targets with cached elements should have been destroyed.
291 typedef std::pair<const TargetData*,const StructType*> LayoutKey;
293 struct DenseMapLayoutKeyInfo {
294 static inline LayoutKey getEmptyKey() { return LayoutKey(0, 0); }
295 static inline LayoutKey getTombstoneKey() {
296 return LayoutKey((TargetData*)(intptr_t)-1, 0);
298 static unsigned getHashValue(const LayoutKey &Val) {
299 return DenseMapKeyInfo<void*>::getHashValue(Val.first) ^
300 DenseMapKeyInfo<void*>::getHashValue(Val.second);
302 static bool isPod() { return true; }
305 typedef DenseMap<LayoutKey, StructLayout*, DenseMapLayoutKeyInfo> LayoutInfoTy;
306 static ManagedStatic<LayoutInfoTy> LayoutInfo;
309 TargetData::~TargetData() {
310 if (LayoutInfo.isConstructed()) {
311 // Remove any layouts for this TD.
312 LayoutInfoTy &TheMap = *LayoutInfo;
313 for (LayoutInfoTy::iterator I = TheMap.begin(), E = TheMap.end();
315 if (I->first.first == this) {
316 I->second->~StructLayout();
326 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
327 LayoutInfoTy &TheMap = *LayoutInfo;
329 StructLayout *&SL = TheMap[LayoutKey(this, Ty)];
332 // Otherwise, create the struct layout. Because it is variable length, we
333 // malloc it, then use placement new.
334 unsigned NumElts = Ty->getNumElements();
336 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1)*sizeof(uint64_t));
338 // Set SL before calling StructLayout's ctor. The ctor could cause other
339 // entries to be added to TheMap, invalidating our reference.
342 new (L) StructLayout(Ty, *this);
346 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
347 /// objects. If a TargetData object is alive when types are being refined and
348 /// removed, this method must be called whenever a StructType is removed to
349 /// avoid a dangling pointer in this cache.
350 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
351 if (!LayoutInfo.isConstructed()) return; // No cache.
353 LayoutInfoTy::iterator I = LayoutInfo->find(LayoutKey(this, Ty));
354 if (I != LayoutInfo->end()) {
355 I->second->~StructLayout();
357 LayoutInfo->erase(I);
362 std::string TargetData::getStringRepresentation() const {
364 repr.append(LittleEndian ? "e" : "E");
365 repr.append("-p:").append(itostr((int64_t) (PointerMemSize * 8))).
366 append(":").append(itostr((int64_t) (PointerABIAlign * 8))).
367 append(":").append(itostr((int64_t) (PointerPrefAlign * 8)));
368 for (align_const_iterator I = Alignments.begin();
369 I != Alignments.end();
371 repr.append("-").append(1, (char) I->AlignType).
372 append(utostr((int64_t) I->TypeBitWidth)).
373 append(":").append(utostr((uint64_t) (I->ABIAlign * 8))).
374 append(":").append(utostr((uint64_t) (I->PrefAlign * 8)));
380 uint64_t TargetData::getTypeSize(const Type *Ty) const {
381 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
382 switch (Ty->getTypeID()) {
383 case Type::LabelTyID:
384 case Type::PointerTyID:
385 return getPointerSize();
386 case Type::ArrayTyID: {
387 const ArrayType *ATy = cast<ArrayType>(Ty);
389 unsigned char Alignment;
390 Size = getTypeSize(ATy->getElementType());
391 Alignment = getABITypeAlignment(ATy->getElementType());
392 unsigned AlignedSize = (Size + Alignment - 1)/Alignment*Alignment;
393 return AlignedSize*ATy->getNumElements();
395 case Type::StructTyID: {
396 // Get the layout annotation... which is lazily created on demand.
397 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
398 return Layout->getSizeInBytes();
400 case Type::IntegerTyID: {
401 unsigned BitWidth = cast<IntegerType>(Ty)->getBitWidth();
404 } else if (BitWidth <= 16) {
406 } else if (BitWidth <= 32) {
408 } else if (BitWidth <= 64) {
411 assert(0 && "Integer types > 64 bits not supported.");
416 case Type::FloatTyID:
418 case Type::DoubleTyID:
420 case Type::VectorTyID: {
421 const VectorType *PTy = cast<VectorType>(Ty);
422 return PTy->getBitWidth() / 8;
425 assert(0 && "TargetData::getTypeSize(): Unsupported type");
431 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
433 return cast<IntegerType>(Ty)->getBitWidth();
435 return getTypeSize(Ty) * 8;
440 \param abi_or_pref Flag that determines which alignment is returned. true
441 returns the ABI alignment, false returns the preferred alignment.
442 \param Ty The underlying type for which alignment is determined.
444 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
445 == false) for the requested type \a Ty.
447 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
450 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
451 switch (Ty->getTypeID()) {
452 /* Early escape for the non-numeric types */
453 case Type::LabelTyID:
454 case Type::PointerTyID:
456 ? getPointerABIAlignment()
457 : getPointerPrefAlignment());
458 case Type::ArrayTyID:
459 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
461 case Type::StructTyID: {
462 // Packed structure types always have an ABI alignment of one.
463 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
466 // Get the layout annotation... which is lazily created on demand.
467 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
468 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref);
469 return std::max(Align, (unsigned)Layout->getAlignment());
471 case Type::IntegerTyID:
473 AlignType = INTEGER_ALIGN;
475 case Type::FloatTyID:
476 case Type::DoubleTyID:
477 AlignType = FLOAT_ALIGN;
479 case Type::VectorTyID:
480 AlignType = VECTOR_ALIGN;
483 assert(0 && "Bad type for getAlignment!!!");
487 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSize(Ty) * 8,
491 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
492 return getAlignment(Ty, true);
495 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
496 return getAlignment(Ty, false);
499 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
500 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
501 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
502 return Log2_32(Align);
505 /// getIntPtrType - Return an unsigned integer type that is the same size or
506 /// greater to the host pointer size.
507 const Type *TargetData::getIntPtrType() const {
508 switch (getPointerSize()) {
509 default: assert(0 && "Unknown pointer size!");
510 case 2: return Type::Int16Ty;
511 case 4: return Type::Int32Ty;
512 case 8: return Type::Int64Ty;
517 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
518 unsigned NumIndices) const {
519 const Type *Ty = ptrTy;
520 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
523 generic_gep_type_iterator<Value* const*>
524 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
525 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
526 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
527 assert(Indices[CurIDX]->getType() == Type::Int32Ty &&"Illegal struct idx");
528 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
530 // Get structure layout information...
531 const StructLayout *Layout = getStructLayout(STy);
533 // Add in the offset, as calculated by the structure layout info...
534 Result += Layout->getElementOffset(FieldNo);
536 // Update Ty to refer to current element
537 Ty = STy->getElementType(FieldNo);
539 // Update Ty to refer to current element
540 Ty = cast<SequentialType>(Ty)->getElementType();
542 // Get the array index and the size of each array element.
543 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
544 Result += arrayIdx * (int64_t)getTypeSize(Ty);
551 /// getPreferredAlignmentLog - Return the preferred alignment of the
552 /// specified global, returned in log form. This includes an explicitly
553 /// requested alignment (if the global has one).
554 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
555 const Type *ElemType = GV->getType()->getElementType();
556 unsigned Alignment = getPreferredTypeAlignmentShift(ElemType);
557 if (GV->getAlignment() > (1U << Alignment))
558 Alignment = Log2_32(GV->getAlignment());
560 if (GV->hasInitializer()) {
562 // If the global is not external, see if it is large. If so, give it a
564 if (getTypeSize(ElemType) > 128)
565 Alignment = 4; // 16-byte alignment.