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/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 static RegisterPass<TargetData> X("targetdata", "Target Data Layout", false,
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() ? 1 : TD.getABITypeAlignment(Ty);
55 // Add padding if necessary to align the data element properly.
56 if ((StructSize & (TyAlign-1)) != 0)
57 StructSize = TargetData::RoundUpAlignment(StructSize, TyAlign);
59 // Keep track of maximum alignment constraint.
60 StructAlignment = std::max(TyAlign, StructAlignment);
62 MemberOffsets[i] = StructSize;
63 StructSize += TD.getTypeAllocSize(Ty); // Consume space for this data item
66 // Empty structures have alignment of 1 byte.
67 if (StructAlignment == 0) StructAlignment = 1;
69 // Add padding to the end of the struct so that it could be put in an array
70 // and all array elements would be aligned correctly.
71 if ((StructSize & (StructAlignment-1)) != 0)
72 StructSize = TargetData::RoundUpAlignment(StructSize, StructAlignment);
76 /// getElementContainingOffset - Given a valid offset into the structure,
77 /// return the structure index that contains it.
78 unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
80 std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
81 assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
83 assert(*SI <= Offset && "upper_bound didn't work");
84 assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
85 (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
86 "Upper bound didn't work!");
88 // Multiple fields can have the same offset if any of them are zero sized.
89 // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
90 // at the i32 element, because it is the last element at that offset. This is
91 // the right one to return, because anything after it will have a higher
92 // offset, implying that this element is non-empty.
93 return SI-&MemberOffsets[0];
96 //===----------------------------------------------------------------------===//
97 // TargetAlignElem, TargetAlign support
98 //===----------------------------------------------------------------------===//
101 TargetAlignElem::get(AlignTypeEnum align_type, unsigned char abi_align,
102 unsigned char pref_align, uint32_t bit_width) {
103 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
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 //===----------------------------------------------------------------------===//
135 /// getInt - Get an integer ignoring errors.
136 static unsigned getInt(StringRef R) {
138 R.getAsInteger(10, Result);
142 void TargetData::init(StringRef Desc) {
144 LittleEndian = false;
147 PointerPrefAlign = PointerABIAlign;
149 // Default alignments
150 setAlignment(INTEGER_ALIGN, 1, 1, 1); // i1
151 setAlignment(INTEGER_ALIGN, 1, 1, 8); // i8
152 setAlignment(INTEGER_ALIGN, 2, 2, 16); // i16
153 setAlignment(INTEGER_ALIGN, 4, 4, 32); // i32
154 setAlignment(INTEGER_ALIGN, 4, 8, 64); // i64
155 setAlignment(FLOAT_ALIGN, 4, 4, 32); // float
156 setAlignment(FLOAT_ALIGN, 8, 8, 64); // double
157 setAlignment(VECTOR_ALIGN, 8, 8, 64); // v2i32, v1i64, ...
158 setAlignment(VECTOR_ALIGN, 16, 16, 128); // v16i8, v8i16, v4i32, ...
159 setAlignment(AGGREGATE_ALIGN, 0, 8, 0); // struct
161 while (!Desc.empty()) {
162 std::pair<StringRef, StringRef> Split = Desc.split('-');
163 StringRef Token = Split.first;
169 Split = Token.split(':');
170 StringRef Specifier = Split.first;
171 Token = Split.second;
173 assert(!Specifier.empty() && "Can't be empty here");
175 switch (Specifier[0]) {
177 LittleEndian = false;
183 Split = Token.split(':');
184 PointerMemSize = getInt(Split.first) / 8;
185 Split = Split.second.split(':');
186 PointerABIAlign = getInt(Split.first) / 8;
187 Split = Split.second.split(':');
188 PointerPrefAlign = getInt(Split.first) / 8;
189 if (PointerPrefAlign == 0)
190 PointerPrefAlign = PointerABIAlign;
197 AlignTypeEnum AlignType;
198 switch (Specifier[0]) {
200 case 'i': AlignType = INTEGER_ALIGN; break;
201 case 'v': AlignType = VECTOR_ALIGN; break;
202 case 'f': AlignType = FLOAT_ALIGN; break;
203 case 'a': AlignType = AGGREGATE_ALIGN; break;
204 case 's': AlignType = STACK_ALIGN; break;
206 unsigned Size = getInt(Specifier.substr(1));
207 Split = Token.split(':');
208 unsigned char ABIAlign = getInt(Split.first) / 8;
210 Split = Split.second.split(':');
211 unsigned char PrefAlign = getInt(Split.first) / 8;
213 PrefAlign = ABIAlign;
214 setAlignment(AlignType, ABIAlign, PrefAlign, Size);
217 case 'n': // Native integer types.
218 Specifier = Specifier.substr(1);
220 if (unsigned Width = getInt(Specifier))
221 LegalIntWidths.push_back(Width);
222 Split = Token.split(':');
223 Specifier = Split.first;
224 Token = Split.second;
225 } while (!Specifier.empty() || !Token.empty());
236 /// @note This has to exist, because this is a pass, but it should never be
238 TargetData::TargetData() : ImmutablePass(&ID) {
239 llvm_report_error("Bad TargetData ctor used. "
240 "Tool did not specify a TargetData to use?");
243 TargetData::TargetData(const Module *M)
244 : ImmutablePass(&ID) {
245 init(M->getDataLayout());
249 TargetData::setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
250 unsigned char pref_align, uint32_t bit_width) {
251 assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
252 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
253 if (Alignments[i].AlignType == align_type &&
254 Alignments[i].TypeBitWidth == bit_width) {
255 // Update the abi, preferred alignments.
256 Alignments[i].ABIAlign = abi_align;
257 Alignments[i].PrefAlign = pref_align;
262 Alignments.push_back(TargetAlignElem::get(align_type, abi_align,
263 pref_align, bit_width));
266 /// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
267 /// preferred if ABIInfo = false) the target wants for the specified datatype.
268 unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
269 uint32_t BitWidth, bool ABIInfo,
270 const Type *Ty) 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 && Alignments[i].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].TypeBitWidth < BitWidth) {
285 // Verify that we pick the biggest of the fallbacks.
286 if (BestMatchIdx == -1 ||
287 Alignments[BestMatchIdx].TypeBitWidth < Alignments[i].TypeBitWidth)
290 } else if (AlignType == INTEGER_ALIGN &&
291 Alignments[i].AlignType == INTEGER_ALIGN) {
292 // The "best match" for integers is the smallest size that is larger than
293 // the BitWidth requested.
294 if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
295 Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
297 // However, if there isn't one that's larger, then we must use the
298 // largest one we have (see below)
299 if (LargestInt == -1 ||
300 Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
305 // Okay, we didn't find an exact solution. Fall back here depending on what
306 // is being looked for.
307 if (BestMatchIdx == -1) {
308 // If we didn't find an integer alignment, fall back on most conservative.
309 if (AlignType == INTEGER_ALIGN) {
310 BestMatchIdx = LargestInt;
312 assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");
314 // If we didn't find a vector size that is smaller or equal to this type,
315 // then we will end up scalarizing this to its element type. Just return
316 // the alignment of the element.
317 return getAlignment(cast<VectorType>(Ty)->getElementType(), ABIInfo);
321 // Since we got a "best match" index, just return it.
322 return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
323 : Alignments[BestMatchIdx].PrefAlign;
326 typedef DenseMap<const StructType*, StructLayout*>LayoutInfoTy;
328 TargetData::~TargetData() {
332 // Remove any layouts for this TD.
333 LayoutInfoTy &TheMap = *static_cast<LayoutInfoTy*>(LayoutMap);
334 for (LayoutInfoTy::iterator I = TheMap.begin(), E = TheMap.end(); I != E; ) {
335 I->second->~StructLayout();
340 delete static_cast<LayoutInfoTy*>(LayoutMap);
343 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
345 LayoutMap = static_cast<void*>(new LayoutInfoTy());
347 LayoutInfoTy &TheMap = *static_cast<LayoutInfoTy*>(LayoutMap);
349 StructLayout *&SL = TheMap[Ty];
352 // Otherwise, create the struct layout. Because it is variable length, we
353 // malloc it, then use placement new.
354 int NumElts = Ty->getNumElements();
356 (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1)*sizeof(uint64_t));
358 // Set SL before calling StructLayout's ctor. The ctor could cause other
359 // entries to be added to TheMap, invalidating our reference.
362 new (L) StructLayout(Ty, *this);
366 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
367 /// objects. If a TargetData object is alive when types are being refined and
368 /// removed, this method must be called whenever a StructType is removed to
369 /// avoid a dangling pointer in this cache.
370 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
371 if (!LayoutMap) return; // No cache.
373 LayoutInfoTy* LayoutInfo = static_cast<LayoutInfoTy*>(LayoutMap);
374 LayoutInfoTy::iterator I = LayoutInfo->find(Ty);
375 if (I == LayoutInfo->end()) return;
377 I->second->~StructLayout();
379 LayoutInfo->erase(I);
383 std::string TargetData::getStringRepresentation() const {
385 raw_string_ostream OS(Result);
387 OS << (LittleEndian ? "e" : "E")
388 << "-p:" << PointerMemSize*8 << ':' << PointerABIAlign*8
389 << ':' << PointerPrefAlign*8;
390 for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
391 const TargetAlignElem &AI = Alignments[i];
392 OS << '-' << (char)AI.AlignType << AI.TypeBitWidth << ':'
393 << AI.ABIAlign*8 << ':' << AI.PrefAlign*8;
396 if (!LegalIntWidths.empty()) {
397 OS << "-n" << (unsigned)LegalIntWidths[0];
399 for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
400 OS << ':' << (unsigned)LegalIntWidths[i];
406 uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
407 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
408 switch (Ty->getTypeID()) {
409 case Type::LabelTyID:
410 case Type::PointerTyID:
411 return getPointerSizeInBits();
412 case Type::ArrayTyID: {
413 const ArrayType *ATy = cast<ArrayType>(Ty);
414 return getTypeAllocSizeInBits(ATy->getElementType())*ATy->getNumElements();
416 case Type::StructTyID:
417 // Get the layout annotation... which is lazily created on demand.
418 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
419 case Type::IntegerTyID:
420 return cast<IntegerType>(Ty)->getBitWidth();
423 case Type::FloatTyID:
425 case Type::DoubleTyID:
427 case Type::PPC_FP128TyID:
428 case Type::FP128TyID:
430 // In memory objects this is always aligned to a higher boundary, but
431 // only 80 bits contain information.
432 case Type::X86_FP80TyID:
434 case Type::VectorTyID:
435 return cast<VectorType>(Ty)->getBitWidth();
437 llvm_unreachable("TargetData::getTypeSizeInBits(): Unsupported type");
444 \param abi_or_pref Flag that determines which alignment is returned. true
445 returns the ABI alignment, false returns the preferred alignment.
446 \param Ty The underlying type for which alignment is determined.
448 Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
449 == false) for the requested type \a Ty.
451 unsigned char TargetData::getAlignment(const Type *Ty, bool abi_or_pref) const {
454 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
455 switch (Ty->getTypeID()) {
456 // Early escape for the non-numeric types.
457 case Type::LabelTyID:
458 case Type::PointerTyID:
460 ? getPointerABIAlignment()
461 : getPointerPrefAlignment());
462 case Type::ArrayTyID:
463 return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);
465 case Type::StructTyID: {
466 // Packed structure types always have an ABI alignment of one.
467 if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
470 // Get the layout annotation... which is lazily created on demand.
471 const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
472 unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
473 return std::max(Align, (unsigned)Layout->getAlignment());
475 case Type::IntegerTyID:
477 AlignType = INTEGER_ALIGN;
479 case Type::FloatTyID:
480 case Type::DoubleTyID:
481 // PPC_FP128TyID and FP128TyID have different data contents, but the
482 // same size and alignment, so they look the same here.
483 case Type::PPC_FP128TyID:
484 case Type::FP128TyID:
485 case Type::X86_FP80TyID:
486 AlignType = FLOAT_ALIGN;
488 case Type::VectorTyID:
489 AlignType = VECTOR_ALIGN;
492 llvm_unreachable("Bad type for getAlignment!!!");
496 return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
500 unsigned char TargetData::getABITypeAlignment(const Type *Ty) const {
501 return getAlignment(Ty, true);
504 unsigned char TargetData::getCallFrameTypeAlignment(const Type *Ty) const {
505 for (unsigned i = 0, e = Alignments.size(); i != e; ++i)
506 if (Alignments[i].AlignType == STACK_ALIGN)
507 return Alignments[i].ABIAlign;
509 return getABITypeAlignment(Ty);
512 unsigned char TargetData::getPrefTypeAlignment(const Type *Ty) const {
513 return getAlignment(Ty, false);
516 unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
517 unsigned Align = (unsigned) getPrefTypeAlignment(Ty);
518 assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
519 return Log2_32(Align);
522 /// getIntPtrType - Return an unsigned integer type that is the same size or
523 /// greater to the host pointer size.
524 const IntegerType *TargetData::getIntPtrType(LLVMContext &C) const {
525 return IntegerType::get(C, getPointerSizeInBits());
529 uint64_t TargetData::getIndexedOffset(const Type *ptrTy, Value* const* Indices,
530 unsigned NumIndices) const {
531 const Type *Ty = ptrTy;
532 assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
535 generic_gep_type_iterator<Value* const*>
536 TI = gep_type_begin(ptrTy, Indices, Indices+NumIndices);
537 for (unsigned CurIDX = 0; CurIDX != NumIndices; ++CurIDX, ++TI) {
538 if (const StructType *STy = dyn_cast<StructType>(*TI)) {
539 assert(Indices[CurIDX]->getType() ==
540 Type::getInt32Ty(ptrTy->getContext()) &&
541 "Illegal struct idx");
542 unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();
544 // Get structure layout information...
545 const StructLayout *Layout = getStructLayout(STy);
547 // Add in the offset, as calculated by the structure layout info...
548 Result += Layout->getElementOffset(FieldNo);
550 // Update Ty to refer to current element
551 Ty = STy->getElementType(FieldNo);
553 // Update Ty to refer to current element
554 Ty = cast<SequentialType>(Ty)->getElementType();
556 // Get the array index and the size of each array element.
557 int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue();
558 Result += arrayIdx * (int64_t)getTypeAllocSize(Ty);
565 /// getPreferredAlignment - Return the preferred alignment of the specified
566 /// global. This includes an explicitly requested alignment (if the global
568 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
569 const Type *ElemType = GV->getType()->getElementType();
570 unsigned Alignment = getPrefTypeAlignment(ElemType);
571 if (GV->getAlignment() > Alignment)
572 Alignment = GV->getAlignment();
574 if (GV->hasInitializer()) {
575 if (Alignment < 16) {
576 // If the global is not external, see if it is large. If so, give it a
578 if (getTypeSizeInBits(ElemType) > 128)
579 Alignment = 16; // 16-byte alignment.
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 return Log2_32(getPreferredAlignment(GV));