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/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"
32 // Handle the Pass registration stuff necessary to use TargetData's.
34 // Register the default SparcV9 implementation...
35 static RegisterPass<TargetData> X("targetdata", "Target Data Layout", false,
37 char TargetData::ID = 0;
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);
51 unsigned TyAlign = ST->isPacked() ? 1 : TD.getABITypeAlignment(Ty);
53 // Add padding if necessary to align the data element properly.
54 if ((StructSize & (TyAlign-1)) != 0)
55 StructSize = TargetData::RoundUpAlignment(StructSize, TyAlign);
57 // Keep track of maximum alignment constraint.
58 StructAlignment = std::max(TyAlign, StructAlignment);
60 MemberOffsets[i] = StructSize;
61 StructSize += TD.getTypeAllocSize(Ty); // Consume space for this data item
64 // Empty structures have alignment of 1 byte.
65 if (StructAlignment == 0) StructAlignment = 1;
67 // Add padding to the end of the struct so that it could be put in an array
68 // and all array elements would be aligned correctly.
69 if ((StructSize & (StructAlignment-1)) != 0)
70 StructSize = TargetData::RoundUpAlignment(StructSize, StructAlignment);
74 /// getElementContainingOffset - Given a valid offset into the structure,
75 /// return the structure index that contains it.
76 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
78 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
79 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
81 assert(*SI <= Offset && "upper_bound didn't work");
82 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
83 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
84 "Upper bound didn't work!");
86 // Multiple fields can have the same offset if any of them are zero sized.
87 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
88 // at the i32 element, because it is the last element at that offset. This is
89 // the right one to return, because anything after it will have a higher
90 // offset, implying that this element is non-empty.
91 return SI-&MemberOffsets[0];
94 //===----------------------------------------------------------------------===//
95 // TargetAlignElem, TargetAlign support
96 //===----------------------------------------------------------------------===//
99 TargetAlignElem::get(AlignTypeEnum align_type, unsigned char abi_align,
100 unsigned char pref_align, uint32_t bit_width) {
101 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
102 TargetAlignElem retval;
103 retval.AlignType = align_type;
104 retval.ABIAlign = abi_align;
105 retval.PrefAlign = pref_align;
106 retval.TypeBitWidth = bit_width;
111 TargetAlignElem::operator==(const TargetAlignElem &rhs) const {
112 return (AlignType == rhs.AlignType
113 && ABIAlign == rhs.ABIAlign
114 && PrefAlign == rhs.PrefAlign
115 && TypeBitWidth == rhs.TypeBitWidth);
119 TargetAlignElem::dump(std::ostream &os) const {
120 return os << AlignType
122 << ":" << (int) (ABIAlign * 8)
123 << ":" << (int) (PrefAlign * 8);
126 const TargetAlignElem TargetData::InvalidAlignmentElem =
127 TargetAlignElem::get((AlignTypeEnum) -1, 0, 0, 0);
129 //===----------------------------------------------------------------------===//
130 // TargetData Class Implementation
131 //===----------------------------------------------------------------------===//
134 A TargetDescription string consists of a sequence of hyphen-delimited
135 specifiers for target endianness, pointer size and alignments, and various
136 primitive type sizes and alignments. A typical string looks something like:
138 "E-p:32:32:32-i1:8:8-i8:8:8-i32:32:32-i64:32:64-f32:32:32-f64:32:64"
140 (note: this string is not fully specified and is only an example.)
142 Alignments come in two flavors: ABI and preferred. ABI alignment (abi_align,
143 below) dictates how a type will be aligned within an aggregate and when used
144 as an argument. Preferred alignment (pref_align, below) determines a type's
145 alignment when emitted as a global.
147 Specifier string details:
149 <i>[E|e]</i>: Endianness. "E" specifies a big-endian target data model, "e"
150 specifies a little-endian target data model.
152 <i>p:@verbatim<size>:<abi_align>:<pref_align>@endverbatim</i>: Pointer size,
153 ABI and preferred alignment.
155 <i>@verbatim<type><size>:<abi_align>:<pref_align>@endverbatim</i>: Numeric type
157 one of <i>i|f|v|a</i>, corresponding to integer, floating point, vector (aka
158 packed) or aggregate. Size indicates the size, e.g., 32 or 64 bits.
160 The default string, fully specified is:
162 "E-p:64:64:64-a0:0:0-f32:32:32-f64:0:64"
163 "-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:0:64"
164 "-v64:64:64-v128:128:128"
166 Note that in the case of aggregates, 0 is the default ABI and preferred
167 alignment. This is a special case, where the aggregate's computed worst-case
168 alignment will be used.
170 void TargetData::init(const std::string &TargetDescription) {
171 std::string temp = TargetDescription;
173 LittleEndian = false;
176 PointerPrefAlign = PointerABIAlign;
178 // Default alignments
179 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
180 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
181 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
182 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
183 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
184 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
185 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
186 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32
187 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
188 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct, union, class, ...
190 while (!temp.empty()) {
191 std::string token = getToken(temp, "-");
192 std::string arg0 = getToken(token, ":");
193 const char *p = arg0.c_str();
196 LittleEndian = false;
202 PointerMemSize = atoi(getToken(token,":").c_str()) / 8;
203 PointerABIAlign = atoi(getToken(token,":").c_str()) / 8;
204 PointerPrefAlign = atoi(getToken(token,":").c_str()) / 8;
205 if (PointerPrefAlign == 0)
206 PointerPrefAlign = PointerABIAlign;
213 AlignTypeEnum align_type = STACK_ALIGN; // Dummy init, silence warning
215 case 'i': align_type = INTEGER_ALIGN; break;
216 case 'v': align_type = VECTOR_ALIGN; break;
217 case 'f': align_type = FLOAT_ALIGN; break;
218 case 'a': align_type = AGGREGATE_ALIGN; break;
219 case 's': align_type = STACK_ALIGN; break;
221 uint32_t size = (uint32_t) atoi(++p);
222 unsigned char abi_align = atoi(getToken(token, ":").c_str()) / 8;
223 unsigned char pref_align = atoi(getToken(token, ":").c_str()) / 8;
225 pref_align = abi_align;
226 setAlignment(align_type, abi_align, pref_align, size);
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 /// LayoutInfo - The lazy cache of structure layout information maintained by
321 /// TargetData. Note that the struct types must have been free'd before
322 /// llvm_shutdown is called (and thus this is deallocated) because all the
323 /// targets with cached elements should have been destroyed.
325 typedef std::pair<const TargetData*,const StructType*> LayoutKey;
327 struct DenseMapLayoutKeyInfo {
328 static inline LayoutKey getEmptyKey() { return LayoutKey(0, 0); }
329 static inline LayoutKey getTombstoneKey() {
330 return LayoutKey((TargetData*)(intptr_t)-1, 0);
332 static unsigned getHashValue(const LayoutKey &Val) {
333 return DenseMapInfo<void*>::getHashValue(Val.first) ^
334 DenseMapInfo<void*>::getHashValue(Val.second);
336 static bool isEqual(const LayoutKey &LHS, const LayoutKey &RHS) {
340 static bool isPod() { return true; }
343 typedef DenseMap<LayoutKey, StructLayout*, DenseMapLayoutKeyInfo> LayoutInfoTy;
347 static ManagedStatic<LayoutInfoTy> LayoutInfo;
349 TargetData::~TargetData() {
350 if (!LayoutInfo.isConstructed())
353 // Remove any layouts for this TD.
354 LayoutInfoTy &TheMap = *LayoutInfo;
355 for (LayoutInfoTy::iterator I = TheMap.begin(), E = TheMap.end(); I != E; ) {
356 if (I->first.first == this) {
357 I->second->~StructLayout();
366 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
367 LayoutInfoTy &TheMap = *LayoutInfo;
369 StructLayout *&SL = TheMap[LayoutKey(this, Ty)];
372 // Otherwise, create the struct layout. Because it is variable length, we
373 // malloc it, then use placement new.
374 int NumElts = Ty->getNumElements();
376 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1)*sizeof(uint64_t));
378 // Set SL before calling StructLayout's ctor. The ctor could cause other
379 // entries to be added to TheMap, invalidating our reference.
382 new (L) StructLayout(Ty, *this);
386 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
387 /// objects. If a TargetData object is alive when types are being refined and
388 /// removed, this method must be called whenever a StructType is removed to
389 /// avoid a dangling pointer in this cache.
390 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
391 if (!LayoutInfo.isConstructed()) return; // No cache.
393 LayoutInfoTy::iterator I = LayoutInfo->find(LayoutKey(this, Ty));
394 if (I == LayoutInfo->end()) return;
396 I->second->~StructLayout();
398 LayoutInfo->erase(I);
402 std::string TargetData::getStringRepresentation() const {
404 repr.append(LittleEndian ? "e" : "E");
405 repr.append("-p:").append(itostr((int64_t) (PointerMemSize * 8))).
406 append(":").append(itostr((int64_t) (PointerABIAlign * 8))).
407 append(":").append(itostr((int64_t) (PointerPrefAlign * 8)));
408 for (align_const_iterator I = Alignments.begin();
409 I != Alignments.end();
411 repr.append("-").append(1, (char) I->AlignType).
412 append(utostr((int64_t) I->TypeBitWidth)).
413 append(":").append(utostr((uint64_t) (I->ABIAlign * 8))).
414 append(":").append(utostr((uint64_t) (I->PrefAlign * 8)));
420 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
421 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
422 switch (Ty->getTypeID()) {
423 case Type::LabelTyID:
424 case Type::PointerTyID:
425 return getPointerSizeInBits();
426 case Type::ArrayTyID: {
427 const ArrayType *ATy = cast<ArrayType>(Ty);
428 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
430 case Type::StructTyID:
431 // Get the layout annotation... which is lazily created on demand.
432 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
433 case Type::IntegerTyID:
434 return cast<IntegerType>(Ty)->getBitWidth();
437 case Type::FloatTyID:
439 case Type::DoubleTyID:
441 case Type::PPC_FP128TyID:
442 case Type::FP128TyID:
444 // In memory objects this is always aligned to a higher boundary, but
445 // only 80 bits contain information.
446 case Type::X86_FP80TyID:
448 case Type::VectorTyID:
449 return cast<VectorType>(Ty)->getBitWidth();
451 assert(0 && "TargetData::getTypeSizeInBits(): Unsupported type");
458 \param abi_or_pref Flag that determines which alignment is returned. true
459 returns the ABI alignment, false returns the preferred alignment.
460 \param Ty The underlying type for which alignment is determined.
462 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
463 == false) for the requested type \a Ty.
465 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
468 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
469 switch (Ty->getTypeID()) {
470 // Early escape for the non-numeric types.
471 case Type::LabelTyID:
472 case Type::PointerTyID:
474 ? getPointerABIAlignment()
475 : getPointerPrefAlignment());
476 case Type::ArrayTyID:
477 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
479 case Type::StructTyID: {
480 // Packed structure types always have an ABI alignment of one.
481 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
484 // Get the layout annotation... which is lazily created on demand.
485 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
486 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
487 return std::max(Align, (unsigned)Layout->getAlignment());
489 case Type::IntegerTyID:
491 AlignType = INTEGER_ALIGN;
493 case Type::FloatTyID:
494 case Type::DoubleTyID:
495 // PPC_FP128TyID and FP128TyID have different data contents, but the
496 // same size and alignment, so they look the same here.
497 case Type::PPC_FP128TyID:
498 case Type::FP128TyID:
499 case Type::X86_FP80TyID:
500 AlignType = FLOAT_ALIGN;
502 case Type::VectorTyID:
503 AlignType = VECTOR_ALIGN;
506 assert(0 && "Bad type for getAlignment!!!");
510 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
514 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
515 return getAlignment(Ty, true);
518 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
519 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
520 if (Alignments[i].AlignType == STACK_ALIGN)
521 return Alignments[i].ABIAlign;
523 return getABITypeAlignment(Ty);
526 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
527 return getAlignment(Ty, false);
530 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
531 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
532 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
533 return Log2_32(Align);
536 /// getIntPtrType - Return an unsigned integer type that is the same size or
537 /// greater to the host pointer size.
538 const IntegerType *TargetData::getIntPtrType() const {
539 return IntegerType::get(getPointerSizeInBits());
543 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
544 unsigned NumIndices) const {
545 const Type *Ty = ptrTy;
546 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
549 generic_gep_type_iterator<Value* const*>
550 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
551 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
552 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
553 assert(Indices[CurIDX]->getType() == Type::Int32Ty &&
554 "Illegal struct idx");
555 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
557 // Get structure layout information...
558 const StructLayout *Layout = getStructLayout(STy);
560 // Add in the offset, as calculated by the structure layout info...
561 Result += Layout->getElementOffset(FieldNo);
563 // Update Ty to refer to current element
564 Ty = STy->getElementType(FieldNo);
566 // Update Ty to refer to current element
567 Ty = cast<SequentialType>(Ty)->getElementType();
569 // Get the array index and the size of each array element.
570 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
571 Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
578 /// getPreferredAlignment - Return the preferred alignment of the specified
579 /// global. This includes an explicitly requested alignment (if the global
581 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
582 const Type *ElemType = GV->getType()->getElementType();
583 unsigned Alignment = getPrefTypeAlignment(ElemType);
584 if (GV->getAlignment() > Alignment)
585 Alignment = GV->getAlignment();
587 if (GV->hasInitializer()) {
588 if (Alignment < 16) {
589 // If the global is not external, see if it is large. If so, give it a
591 if (getTypeSizeInBits(ElemType) > 128)
592 Alignment = 16; // 16-byte alignment.
598 /// getPreferredAlignmentLog - Return the preferred alignment of the
599 /// specified global, returned in log form. This includes an explicitly
600 /// requested alignment (if the global has one).
601 unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
602 return Log2_32(getPreferredAlignment(GV));