clang  6.0.0svn
SwiftCallingConv.cpp
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1 //===--- SwiftCallingConv.cpp - Lowering for the Swift calling convention -===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Implementation of the abstract lowering for the Swift calling convention.
11 //
12 //===----------------------------------------------------------------------===//
13 
15 #include "clang/Basic/TargetInfo.h"
16 #include "CodeGenModule.h"
17 #include "TargetInfo.h"
18 
19 using namespace clang;
20 using namespace CodeGen;
21 using namespace swiftcall;
22 
24  return cast<SwiftABIInfo>(CGM.getTargetCodeGenInfo().getABIInfo());
25 }
26 
27 static bool isPowerOf2(unsigned n) {
28  return n == (n & -n);
29 }
30 
31 /// Given two types with the same size, try to find a common type.
32 static llvm::Type *getCommonType(llvm::Type *first, llvm::Type *second) {
33  assert(first != second);
34 
35  // Allow pointers to merge with integers, but prefer the integer type.
36  if (first->isIntegerTy()) {
37  if (second->isPointerTy()) return first;
38  } else if (first->isPointerTy()) {
39  if (second->isIntegerTy()) return second;
40  if (second->isPointerTy()) return first;
41 
42  // Allow two vectors to be merged (given that they have the same size).
43  // This assumes that we never have two different vector register sets.
44  } else if (auto firstVecTy = dyn_cast<llvm::VectorType>(first)) {
45  if (auto secondVecTy = dyn_cast<llvm::VectorType>(second)) {
46  if (auto commonTy = getCommonType(firstVecTy->getElementType(),
47  secondVecTy->getElementType())) {
48  return (commonTy == firstVecTy->getElementType() ? first : second);
49  }
50  }
51  }
52 
53  return nullptr;
54 }
55 
57  return CharUnits::fromQuantity(CGM.getDataLayout().getTypeStoreSize(type));
58 }
59 
61  return CharUnits::fromQuantity(CGM.getDataLayout().getTypeAllocSize(type));
62 }
63 
65  // Deal with various aggregate types as special cases:
66 
67  // Record types.
68  if (auto recType = type->getAs<RecordType>()) {
69  addTypedData(recType->getDecl(), begin);
70 
71  // Array types.
72  } else if (type->isArrayType()) {
73  // Incomplete array types (flexible array members?) don't provide
74  // data to lay out, and the other cases shouldn't be possible.
75  auto arrayType = CGM.getContext().getAsConstantArrayType(type);
76  if (!arrayType) return;
77 
78  QualType eltType = arrayType->getElementType();
79  auto eltSize = CGM.getContext().getTypeSizeInChars(eltType);
80  for (uint64_t i = 0, e = arrayType->getSize().getZExtValue(); i != e; ++i) {
81  addTypedData(eltType, begin + i * eltSize);
82  }
83 
84  // Complex types.
85  } else if (auto complexType = type->getAs<ComplexType>()) {
86  auto eltType = complexType->getElementType();
87  auto eltSize = CGM.getContext().getTypeSizeInChars(eltType);
88  auto eltLLVMType = CGM.getTypes().ConvertType(eltType);
89  addTypedData(eltLLVMType, begin, begin + eltSize);
90  addTypedData(eltLLVMType, begin + eltSize, begin + 2 * eltSize);
91 
92  // Member pointer types.
93  } else if (type->getAs<MemberPointerType>()) {
94  // Just add it all as opaque.
95  addOpaqueData(begin, begin + CGM.getContext().getTypeSizeInChars(type));
96 
97  // Everything else is scalar and should not convert as an LLVM aggregate.
98  } else {
99  // We intentionally convert as !ForMem because we want to preserve
100  // that a type was an i1.
101  auto llvmType = CGM.getTypes().ConvertType(type);
102  addTypedData(llvmType, begin);
103  }
104 }
105 
107  addTypedData(record, begin, CGM.getContext().getASTRecordLayout(record));
108 }
109 
111  const ASTRecordLayout &layout) {
112  // Unions are a special case.
113  if (record->isUnion()) {
114  for (auto field : record->fields()) {
115  if (field->isBitField()) {
116  addBitFieldData(field, begin, 0);
117  } else {
118  addTypedData(field->getType(), begin);
119  }
120  }
121  return;
122  }
123 
124  // Note that correctness does not rely on us adding things in
125  // their actual order of layout; it's just somewhat more efficient
126  // for the builder.
127 
128  // With that in mind, add "early" C++ data.
129  auto cxxRecord = dyn_cast<CXXRecordDecl>(record);
130  if (cxxRecord) {
131  // - a v-table pointer, if the class adds its own
132  if (layout.hasOwnVFPtr()) {
133  addTypedData(CGM.Int8PtrTy, begin);
134  }
135 
136  // - non-virtual bases
137  for (auto &baseSpecifier : cxxRecord->bases()) {
138  if (baseSpecifier.isVirtual()) continue;
139 
140  auto baseRecord = baseSpecifier.getType()->getAsCXXRecordDecl();
141  addTypedData(baseRecord, begin + layout.getBaseClassOffset(baseRecord));
142  }
143 
144  // - a vbptr if the class adds its own
145  if (layout.hasOwnVBPtr()) {
146  addTypedData(CGM.Int8PtrTy, begin + layout.getVBPtrOffset());
147  }
148  }
149 
150  // Add fields.
151  for (auto field : record->fields()) {
152  auto fieldOffsetInBits = layout.getFieldOffset(field->getFieldIndex());
153  if (field->isBitField()) {
154  addBitFieldData(field, begin, fieldOffsetInBits);
155  } else {
156  addTypedData(field->getType(),
157  begin + CGM.getContext().toCharUnitsFromBits(fieldOffsetInBits));
158  }
159  }
160 
161  // Add "late" C++ data:
162  if (cxxRecord) {
163  // - virtual bases
164  for (auto &vbaseSpecifier : cxxRecord->vbases()) {
165  auto baseRecord = vbaseSpecifier.getType()->getAsCXXRecordDecl();
166  addTypedData(baseRecord, begin + layout.getVBaseClassOffset(baseRecord));
167  }
168  }
169 }
170 
171 void SwiftAggLowering::addBitFieldData(const FieldDecl *bitfield,
172  CharUnits recordBegin,
173  uint64_t bitfieldBitBegin) {
174  assert(bitfield->isBitField());
175  auto &ctx = CGM.getContext();
176  auto width = bitfield->getBitWidthValue(ctx);
177 
178  // We can ignore zero-width bit-fields.
179  if (width == 0) return;
180 
181  // toCharUnitsFromBits rounds down.
182  CharUnits bitfieldByteBegin = ctx.toCharUnitsFromBits(bitfieldBitBegin);
183 
184  // Find the offset of the last byte that is partially occupied by the
185  // bit-field; since we otherwise expect exclusive ends, the end is the
186  // next byte.
187  uint64_t bitfieldBitLast = bitfieldBitBegin + width - 1;
188  CharUnits bitfieldByteEnd =
189  ctx.toCharUnitsFromBits(bitfieldBitLast) + CharUnits::One();
190  addOpaqueData(recordBegin + bitfieldByteBegin,
191  recordBegin + bitfieldByteEnd);
192 }
193 
195  assert(type && "didn't provide type for typed data");
196  addTypedData(type, begin, begin + getTypeStoreSize(CGM, type));
197 }
198 
200  CharUnits begin, CharUnits end) {
201  assert(type && "didn't provide type for typed data");
202  assert(getTypeStoreSize(CGM, type) == end - begin);
203 
204  // Legalize vector types.
205  if (auto vecTy = dyn_cast<llvm::VectorType>(type)) {
206  SmallVector<llvm::Type*, 4> componentTys;
207  legalizeVectorType(CGM, end - begin, vecTy, componentTys);
208  assert(componentTys.size() >= 1);
209 
210  // Walk the initial components.
211  for (size_t i = 0, e = componentTys.size(); i != e - 1; ++i) {
212  llvm::Type *componentTy = componentTys[i];
213  auto componentSize = getTypeStoreSize(CGM, componentTy);
214  assert(componentSize < end - begin);
215  addLegalTypedData(componentTy, begin, begin + componentSize);
216  begin += componentSize;
217  }
218 
219  return addLegalTypedData(componentTys.back(), begin, end);
220  }
221 
222  // Legalize integer types.
223  if (auto intTy = dyn_cast<llvm::IntegerType>(type)) {
224  if (!isLegalIntegerType(CGM, intTy))
225  return addOpaqueData(begin, end);
226  }
227 
228  // All other types should be legal.
229  return addLegalTypedData(type, begin, end);
230 }
231 
232 void SwiftAggLowering::addLegalTypedData(llvm::Type *type,
233  CharUnits begin, CharUnits end) {
234  // Require the type to be naturally aligned.
235  if (!begin.isZero() && !begin.isMultipleOf(getNaturalAlignment(CGM, type))) {
236 
237  // Try splitting vector types.
238  if (auto vecTy = dyn_cast<llvm::VectorType>(type)) {
239  auto split = splitLegalVectorType(CGM, end - begin, vecTy);
240  auto eltTy = split.first;
241  auto numElts = split.second;
242 
243  auto eltSize = (end - begin) / numElts;
244  assert(eltSize == getTypeStoreSize(CGM, eltTy));
245  for (size_t i = 0, e = numElts; i != e; ++i) {
246  addLegalTypedData(eltTy, begin, begin + eltSize);
247  begin += eltSize;
248  }
249  assert(begin == end);
250  return;
251  }
252 
253  return addOpaqueData(begin, end);
254  }
255 
256  addEntry(type, begin, end);
257 }
258 
259 void SwiftAggLowering::addEntry(llvm::Type *type,
260  CharUnits begin, CharUnits end) {
261  assert((!type ||
262  (!isa<llvm::StructType>(type) && !isa<llvm::ArrayType>(type))) &&
263  "cannot add aggregate-typed data");
264  assert(!type || begin.isMultipleOf(getNaturalAlignment(CGM, type)));
265 
266  // Fast path: we can just add entries to the end.
267  if (Entries.empty() || Entries.back().End <= begin) {
268  Entries.push_back({begin, end, type});
269  return;
270  }
271 
272  // Find the first existing entry that ends after the start of the new data.
273  // TODO: do a binary search if Entries is big enough for it to matter.
274  size_t index = Entries.size() - 1;
275  while (index != 0) {
276  if (Entries[index - 1].End <= begin) break;
277  --index;
278  }
279 
280  // The entry ends after the start of the new data.
281  // If the entry starts after the end of the new data, there's no conflict.
282  if (Entries[index].Begin >= end) {
283  // This insertion is potentially O(n), but the way we generally build
284  // these layouts makes that unlikely to matter: we'd need a union of
285  // several very large types.
286  Entries.insert(Entries.begin() + index, {begin, end, type});
287  return;
288  }
289 
290  // Otherwise, the ranges overlap. The new range might also overlap
291  // with later ranges.
292 restartAfterSplit:
293 
294  // Simplest case: an exact overlap.
295  if (Entries[index].Begin == begin && Entries[index].End == end) {
296  // If the types match exactly, great.
297  if (Entries[index].Type == type) return;
298 
299  // If either type is opaque, make the entry opaque and return.
300  if (Entries[index].Type == nullptr) {
301  return;
302  } else if (type == nullptr) {
303  Entries[index].Type = nullptr;
304  return;
305  }
306 
307  // If they disagree in an ABI-agnostic way, just resolve the conflict
308  // arbitrarily.
309  if (auto entryType = getCommonType(Entries[index].Type, type)) {
310  Entries[index].Type = entryType;
311  return;
312  }
313 
314  // Otherwise, make the entry opaque.
315  Entries[index].Type = nullptr;
316  return;
317  }
318 
319  // Okay, we have an overlapping conflict of some sort.
320 
321  // If we have a vector type, split it.
322  if (auto vecTy = dyn_cast_or_null<llvm::VectorType>(type)) {
323  auto eltTy = vecTy->getElementType();
324  CharUnits eltSize = (end - begin) / vecTy->getNumElements();
325  assert(eltSize == getTypeStoreSize(CGM, eltTy));
326  for (unsigned i = 0, e = vecTy->getNumElements(); i != e; ++i) {
327  addEntry(eltTy, begin, begin + eltSize);
328  begin += eltSize;
329  }
330  assert(begin == end);
331  return;
332  }
333 
334  // If the entry is a vector type, split it and try again.
335  if (Entries[index].Type && Entries[index].Type->isVectorTy()) {
336  splitVectorEntry(index);
337  goto restartAfterSplit;
338  }
339 
340  // Okay, we have no choice but to make the existing entry opaque.
341 
342  Entries[index].Type = nullptr;
343 
344  // Stretch the start of the entry to the beginning of the range.
345  if (begin < Entries[index].Begin) {
346  Entries[index].Begin = begin;
347  assert(index == 0 || begin >= Entries[index - 1].End);
348  }
349 
350  // Stretch the end of the entry to the end of the range; but if we run
351  // into the start of the next entry, just leave the range there and repeat.
352  while (end > Entries[index].End) {
353  assert(Entries[index].Type == nullptr);
354 
355  // If the range doesn't overlap the next entry, we're done.
356  if (index == Entries.size() - 1 || end <= Entries[index + 1].Begin) {
357  Entries[index].End = end;
358  break;
359  }
360 
361  // Otherwise, stretch to the start of the next entry.
362  Entries[index].End = Entries[index + 1].Begin;
363 
364  // Continue with the next entry.
365  index++;
366 
367  // This entry needs to be made opaque if it is not already.
368  if (Entries[index].Type == nullptr)
369  continue;
370 
371  // Split vector entries unless we completely subsume them.
372  if (Entries[index].Type->isVectorTy() &&
373  end < Entries[index].End) {
374  splitVectorEntry(index);
375  }
376 
377  // Make the entry opaque.
378  Entries[index].Type = nullptr;
379  }
380 }
381 
382 /// Replace the entry of vector type at offset 'index' with a sequence
383 /// of its component vectors.
384 void SwiftAggLowering::splitVectorEntry(unsigned index) {
385  auto vecTy = cast<llvm::VectorType>(Entries[index].Type);
386  auto split = splitLegalVectorType(CGM, Entries[index].getWidth(), vecTy);
387 
388  auto eltTy = split.first;
389  CharUnits eltSize = getTypeStoreSize(CGM, eltTy);
390  auto numElts = split.second;
391  Entries.insert(Entries.begin() + index + 1, numElts - 1, StorageEntry());
392 
393  CharUnits begin = Entries[index].Begin;
394  for (unsigned i = 0; i != numElts; ++i) {
395  Entries[index].Type = eltTy;
396  Entries[index].Begin = begin;
397  Entries[index].End = begin + eltSize;
398  begin += eltSize;
399  }
400 }
401 
402 /// Given a power-of-two unit size, return the offset of the aligned unit
403 /// of that size which contains the given offset.
404 ///
405 /// In other words, round down to the nearest multiple of the unit size.
407  assert(isPowerOf2(unitSize.getQuantity()));
408  auto unitMask = ~(unitSize.getQuantity() - 1);
409  return CharUnits::fromQuantity(offset.getQuantity() & unitMask);
410 }
411 
412 static bool areBytesInSameUnit(CharUnits first, CharUnits second,
413  CharUnits chunkSize) {
414  return getOffsetAtStartOfUnit(first, chunkSize)
415  == getOffsetAtStartOfUnit(second, chunkSize);
416 }
417 
419  if (Entries.empty()) {
420  Finished = true;
421  return;
422  }
423 
424  // We logically split the layout down into a series of chunks of this size,
425  // which is generally the size of a pointer.
426  const CharUnits chunkSize = getMaximumVoluntaryIntegerSize(CGM);
427 
428  // First pass: if two entries share a chunk, make them both opaque
429  // and stretch one to meet the next.
430  bool hasOpaqueEntries = (Entries[0].Type == nullptr);
431  for (size_t i = 1, e = Entries.size(); i != e; ++i) {
432  if (areBytesInSameUnit(Entries[i - 1].End - CharUnits::One(),
433  Entries[i].Begin, chunkSize)) {
434  Entries[i - 1].Type = nullptr;
435  Entries[i].Type = nullptr;
436  Entries[i - 1].End = Entries[i].Begin;
437  hasOpaqueEntries = true;
438 
439  } else if (Entries[i].Type == nullptr) {
440  hasOpaqueEntries = true;
441  }
442  }
443 
444  // The rest of the algorithm leaves non-opaque entries alone, so if we
445  // have no opaque entries, we're done.
446  if (!hasOpaqueEntries) {
447  Finished = true;
448  return;
449  }
450 
451  // Okay, move the entries to a temporary and rebuild Entries.
452  auto orig = std::move(Entries);
453  assert(Entries.empty());
454 
455  for (size_t i = 0, e = orig.size(); i != e; ++i) {
456  // Just copy over non-opaque entries.
457  if (orig[i].Type != nullptr) {
458  Entries.push_back(orig[i]);
459  continue;
460  }
461 
462  // Scan forward to determine the full extent of the next opaque range.
463  // We know from the first pass that only contiguous ranges will overlap
464  // the same aligned chunk.
465  auto begin = orig[i].Begin;
466  auto end = orig[i].End;
467  while (i + 1 != e &&
468  orig[i + 1].Type == nullptr &&
469  end == orig[i + 1].Begin) {
470  end = orig[i + 1].End;
471  i++;
472  }
473 
474  // Add an entry per intersected chunk.
475  do {
476  // Find the smallest aligned storage unit in the maximal aligned
477  // storage unit containing 'begin' that contains all the bytes in
478  // the intersection between the range and this chunk.
479  CharUnits localBegin = begin;
480  CharUnits chunkBegin = getOffsetAtStartOfUnit(localBegin, chunkSize);
481  CharUnits chunkEnd = chunkBegin + chunkSize;
482  CharUnits localEnd = std::min(end, chunkEnd);
483 
484  // Just do a simple loop over ever-increasing unit sizes.
485  CharUnits unitSize = CharUnits::One();
486  CharUnits unitBegin, unitEnd;
487  for (; ; unitSize *= 2) {
488  assert(unitSize <= chunkSize);
489  unitBegin = getOffsetAtStartOfUnit(localBegin, unitSize);
490  unitEnd = unitBegin + unitSize;
491  if (unitEnd >= localEnd) break;
492  }
493 
494  // Add an entry for this unit.
495  auto entryTy =
496  llvm::IntegerType::get(CGM.getLLVMContext(),
497  CGM.getContext().toBits(unitSize));
498  Entries.push_back({unitBegin, unitEnd, entryTy});
499 
500  // The next chunk starts where this chunk left off.
501  begin = localEnd;
502  } while (begin != end);
503  }
504 
505  // Okay, finally finished.
506  Finished = true;
507 }
508 
510  assert(Finished && "haven't yet finished lowering");
511 
512  for (auto &entry : Entries) {
513  callback(entry.Begin, entry.End, entry.Type);
514  }
515 }
516 
517 std::pair<llvm::StructType*, llvm::Type*>
519  assert(Finished && "haven't yet finished lowering");
520 
521  auto &ctx = CGM.getLLVMContext();
522 
523  if (Entries.empty()) {
524  auto type = llvm::StructType::get(ctx);
525  return { type, type };
526  }
527 
529  CharUnits lastEnd = CharUnits::Zero();
530  bool hasPadding = false;
531  bool packed = false;
532  for (auto &entry : Entries) {
533  if (entry.Begin != lastEnd) {
534  auto paddingSize = entry.Begin - lastEnd;
535  assert(!paddingSize.isNegative());
536 
537  auto padding = llvm::ArrayType::get(llvm::Type::getInt8Ty(ctx),
538  paddingSize.getQuantity());
539  elts.push_back(padding);
540  hasPadding = true;
541  }
542 
543  if (!packed && !entry.Begin.isMultipleOf(
545  CGM.getDataLayout().getABITypeAlignment(entry.Type))))
546  packed = true;
547 
548  elts.push_back(entry.Type);
549 
550  lastEnd = entry.Begin + getTypeAllocSize(CGM, entry.Type);
551  assert(entry.End <= lastEnd);
552  }
553 
554  // We don't need to adjust 'packed' to deal with possible tail padding
555  // because we never do that kind of access through the coercion type.
556  auto coercionType = llvm::StructType::get(ctx, elts, packed);
557 
558  llvm::Type *unpaddedType = coercionType;
559  if (hasPadding) {
560  elts.clear();
561  for (auto &entry : Entries) {
562  elts.push_back(entry.Type);
563  }
564  if (elts.size() == 1) {
565  unpaddedType = elts[0];
566  } else {
567  unpaddedType = llvm::StructType::get(ctx, elts, /*packed*/ false);
568  }
569  } else if (Entries.size() == 1) {
570  unpaddedType = Entries[0].Type;
571  }
572 
573  return { coercionType, unpaddedType };
574 }
575 
576 bool SwiftAggLowering::shouldPassIndirectly(bool asReturnValue) const {
577  assert(Finished && "haven't yet finished lowering");
578 
579  // Empty types don't need to be passed indirectly.
580  if (Entries.empty()) return false;
581 
582  CharUnits totalSize = Entries.back().End;
583 
584  // Avoid copying the array of types when there's just a single element.
585  if (Entries.size() == 1) {
586  return getSwiftABIInfo(CGM).shouldPassIndirectlyForSwift(totalSize,
587  Entries.back().Type,
588  asReturnValue);
589  }
590 
591  SmallVector<llvm::Type*, 8> componentTys;
592  componentTys.reserve(Entries.size());
593  for (auto &entry : Entries) {
594  componentTys.push_back(entry.Type);
595  }
596  return getSwiftABIInfo(CGM).shouldPassIndirectlyForSwift(totalSize,
597  componentTys,
598  asReturnValue);
599 }
600 
602  // Currently always the size of an ordinary pointer.
603  return CGM.getContext().toCharUnitsFromBits(
605 }
606 
608  // For Swift's purposes, this is always just the store size of the type
609  // rounded up to a power of 2.
610  auto size = (unsigned long long) getTypeStoreSize(CGM, type).getQuantity();
611  if (!isPowerOf2(size)) {
612  size = 1ULL << (llvm::findLastSet(size, llvm::ZB_Undefined) + 1);
613  }
614  assert(size >= CGM.getDataLayout().getABITypeAlignment(type));
615  return CharUnits::fromQuantity(size);
616 }
617 
619  llvm::IntegerType *intTy) {
620  auto size = intTy->getBitWidth();
621  switch (size) {
622  case 1:
623  case 8:
624  case 16:
625  case 32:
626  case 64:
627  // Just assume that the above are always legal.
628  return true;
629 
630  case 128:
631  return CGM.getContext().getTargetInfo().hasInt128Type();
632 
633  default:
634  return false;
635  }
636 }
637 
639  llvm::VectorType *vectorTy) {
640  return isLegalVectorType(CGM, vectorSize, vectorTy->getElementType(),
641  vectorTy->getNumElements());
642 }
643 
645  llvm::Type *eltTy, unsigned numElts) {
646  assert(numElts > 1 && "illegal vector length");
647  return getSwiftABIInfo(CGM)
648  .isLegalVectorTypeForSwift(vectorSize, eltTy, numElts);
649 }
650 
651 std::pair<llvm::Type*, unsigned>
653  llvm::VectorType *vectorTy) {
654  auto numElts = vectorTy->getNumElements();
655  auto eltTy = vectorTy->getElementType();
656 
657  // Try to split the vector type in half.
658  if (numElts >= 4 && isPowerOf2(numElts)) {
659  if (isLegalVectorType(CGM, vectorSize / 2, eltTy, numElts / 2))
660  return {llvm::VectorType::get(eltTy, numElts / 2), 2};
661  }
662 
663  return {eltTy, numElts};
664 }
665 
667  llvm::VectorType *origVectorTy,
669  // If it's already a legal vector type, use it.
670  if (isLegalVectorType(CGM, origVectorSize, origVectorTy)) {
671  components.push_back(origVectorTy);
672  return;
673  }
674 
675  // Try to split the vector into legal subvectors.
676  auto numElts = origVectorTy->getNumElements();
677  auto eltTy = origVectorTy->getElementType();
678  assert(numElts != 1);
679 
680  // The largest size that we're still considering making subvectors of.
681  // Always a power of 2.
682  unsigned logCandidateNumElts = llvm::findLastSet(numElts, llvm::ZB_Undefined);
683  unsigned candidateNumElts = 1U << logCandidateNumElts;
684  assert(candidateNumElts <= numElts && candidateNumElts * 2 > numElts);
685 
686  // Minor optimization: don't check the legality of this exact size twice.
687  if (candidateNumElts == numElts) {
688  logCandidateNumElts--;
689  candidateNumElts >>= 1;
690  }
691 
692  CharUnits eltSize = (origVectorSize / numElts);
693  CharUnits candidateSize = eltSize * candidateNumElts;
694 
695  // The sensibility of this algorithm relies on the fact that we never
696  // have a legal non-power-of-2 vector size without having the power of 2
697  // also be legal.
698  while (logCandidateNumElts > 0) {
699  assert(candidateNumElts == 1U << logCandidateNumElts);
700  assert(candidateNumElts <= numElts);
701  assert(candidateSize == eltSize * candidateNumElts);
702 
703  // Skip illegal vector sizes.
704  if (!isLegalVectorType(CGM, candidateSize, eltTy, candidateNumElts)) {
705  logCandidateNumElts--;
706  candidateNumElts /= 2;
707  candidateSize /= 2;
708  continue;
709  }
710 
711  // Add the right number of vectors of this size.
712  auto numVecs = numElts >> logCandidateNumElts;
713  components.append(numVecs, llvm::VectorType::get(eltTy, candidateNumElts));
714  numElts -= (numVecs << logCandidateNumElts);
715 
716  if (numElts == 0) return;
717 
718  // It's possible that the number of elements remaining will be legal.
719  // This can happen with e.g. <7 x float> when <3 x float> is legal.
720  // This only needs to be separately checked if it's not a power of 2.
721  if (numElts > 2 && !isPowerOf2(numElts) &&
722  isLegalVectorType(CGM, eltSize * numElts, eltTy, numElts)) {
723  components.push_back(llvm::VectorType::get(eltTy, numElts));
724  return;
725  }
726 
727  // Bring vecSize down to something no larger than numElts.
728  do {
729  logCandidateNumElts--;
730  candidateNumElts /= 2;
731  candidateSize /= 2;
732  } while (candidateNumElts > numElts);
733  }
734 
735  // Otherwise, just append a bunch of individual elements.
736  components.append(numElts, eltTy);
737 }
738 
740  const CXXRecordDecl *record) {
741  // Following a recommendation from Richard Smith, pass a C++ type
742  // indirectly only if the destructor is non-trivial or *all* of the
743  // copy/move constructors are deleted or non-trivial.
744 
745  if (record->hasNonTrivialDestructor())
746  return true;
747 
748  // It would be nice if this were summarized on the CXXRecordDecl.
749  for (auto ctor : record->ctors()) {
750  if (ctor->isCopyOrMoveConstructor() && !ctor->isDeleted() &&
751  ctor->isTrivial()) {
752  return false;
753  }
754  }
755 
756  return true;
757 }
758 
760  bool forReturn,
761  CharUnits alignmentForIndirect) {
762  if (lowering.empty()) {
763  return ABIArgInfo::getIgnore();
764  } else if (lowering.shouldPassIndirectly(forReturn)) {
765  return ABIArgInfo::getIndirect(alignmentForIndirect, /*byval*/ false);
766  } else {
767  auto types = lowering.getCoerceAndExpandTypes();
768  return ABIArgInfo::getCoerceAndExpand(types.first, types.second);
769  }
770 }
771 
773  bool forReturn) {
774  if (auto recordType = dyn_cast<RecordType>(type)) {
775  auto record = recordType->getDecl();
776  auto &layout = CGM.getContext().getASTRecordLayout(record);
777 
778  if (auto cxxRecord = dyn_cast<CXXRecordDecl>(record)) {
779  if (shouldPassCXXRecordIndirectly(CGM, cxxRecord))
780  return ABIArgInfo::getIndirect(layout.getAlignment(), /*byval*/ false);
781  }
782 
783  SwiftAggLowering lowering(CGM);
784  lowering.addTypedData(recordType->getDecl(), CharUnits::Zero(), layout);
785  lowering.finish();
786 
787  return classifyExpandedType(lowering, forReturn, layout.getAlignment());
788  }
789 
790  // Just assume that all of our target ABIs can support returning at least
791  // two integer or floating-point values.
792  if (isa<ComplexType>(type)) {
793  return (forReturn ? ABIArgInfo::getDirect() : ABIArgInfo::getExpand());
794  }
795 
796  // Vector types may need to be legalized.
797  if (isa<VectorType>(type)) {
798  SwiftAggLowering lowering(CGM);
799  lowering.addTypedData(type, CharUnits::Zero());
800  lowering.finish();
801 
802  CharUnits alignment = CGM.getContext().getTypeAlignInChars(type);
803  return classifyExpandedType(lowering, forReturn, alignment);
804  }
805 
806  // Member pointer types need to be expanded, but it's a simple form of
807  // expansion that 'Direct' can handle. Note that CanBeFlattened should be
808  // true for this to work.
809 
810  // 'void' needs to be ignored.
811  if (type->isVoidType()) {
812  return ABIArgInfo::getIgnore();
813  }
814 
815  // Everything else can be passed directly.
816  return ABIArgInfo::getDirect();
817 }
818 
820  return classifyType(CGM, type, /*forReturn*/ true);
821 }
822 
824  CanQualType type) {
825  return classifyType(CGM, type, /*forReturn*/ false);
826 }
827 
829  auto &retInfo = FI.getReturnInfo();
830  retInfo = classifyReturnType(CGM, FI.getReturnType());
831 
832  for (unsigned i = 0, e = FI.arg_size(); i != e; ++i) {
833  auto &argInfo = FI.arg_begin()[i];
834  argInfo.info = classifyArgumentType(CGM, argInfo.type);
835  }
836 }
837 
838 // Is swifterror lowered to a register by the target ABI.
841 }
const llvm::DataLayout & getDataLayout() const
const internal::VariadicAllOfMatcher< Type > type
Matches Types in the clang AST.
A (possibly-)qualified type.
Definition: Type.h:653
bool isArrayType() const
Definition: Type.h:5993
llvm::LLVMContext & getLLVMContext()
static ABIArgInfo classifyType(CodeGenModule &CGM, CanQualType type, bool forReturn)
const ASTRecordLayout & getASTRecordLayout(const RecordDecl *D) const
Get or compute information about the layout of the specified record (struct/union/class) D...
CharUnits getBaseClassOffset(const CXXRecordDecl *Base) const
getBaseClassOffset - Get the offset, in chars, for the given base class.
Definition: RecordLayout.h:223
The base class of the type hierarchy.
Definition: Type.h:1353
const ABIInfo & getABIInfo() const
getABIInfo() - Returns ABI info helper for the target.
Definition: TargetInfo.h:55
bool isZero() const
isZero - Test whether the quantity equals zero.
Definition: CharUnits.h:116
const TargetInfo & getTargetInfo() const
Definition: ASTContext.h:671
virtual bool shouldPassIndirectlyForSwift(CharUnits totalSize, ArrayRef< llvm::Type *> types, bool asReturnValue) const =0
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6307
bool hasOwnVFPtr() const
hasOwnVFPtr - Does this class provide its own virtual-function table pointer, rather than inheriting ...
Definition: RecordLayout.h:250
std::pair< llvm::Type *, unsigned > splitLegalVectorType(CodeGenModule &CGM, CharUnits vectorSize, llvm::VectorType *vectorTy)
Minimally split a legal vector type.
static ABIArgInfo getIgnore()
const AstTypeMatcher< RecordType > recordType
Matches record types (e.g.
RecordDecl - Represents a struct/union/class.
Definition: Decl.h:3482
uint64_t getPointerWidth(unsigned AddrSpace) const
Return the width of pointers on this target, for the specified address space.
Definition: TargetInfo.h:311
llvm::Type * ConvertType(QualType T)
ConvertType - Convert type T into a llvm::Type.
ABIArgInfo classifyArgumentType(CodeGenModule &CGM, CanQualType type)
Classify the rules for how to pass a particular type.
static CharUnits getTypeAllocSize(CodeGenModule &CGM, llvm::Type *type)
field_range fields() const
Definition: Decl.h:3613
FieldDecl - An instance of this class is created by Sema::ActOnField to represent a member of a struc...
Definition: Decl.h:2461
static bool isPowerOf2(unsigned n)
ABIArgInfo classifyReturnType(CodeGenModule &CGM, CanQualType type)
Classify the rules for how to return a particular type.
static CharUnits Zero()
Zero - Construct a CharUnits quantity of zero.
Definition: CharUnits.h:53
CharUnits getVBaseClassOffset(const CXXRecordDecl *VBase) const
getVBaseClassOffset - Get the offset, in chars, for the given base class.
Definition: RecordLayout.h:231
const AstTypeMatcher< ComplexType > complexType
Matches C99 complex types.
static ABIArgInfo getDirect(llvm::Type *T=nullptr, unsigned Offset=0, llvm::Type *Padding=nullptr, bool CanBeFlattened=true)
bool isBitField() const
Determines whether this field is a bitfield.
Definition: Decl.h:2539
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
const_arg_iterator arg_begin() const
llvm::function_ref< void(CharUnits offset, CharUnits end, llvm::Type *type)> EnumerationCallback
ABIArgInfo - Helper class to encapsulate information about how a specific C type should be passed to ...
virtual bool isSwiftErrorInRegister() const =0
static ABIArgInfo classifyExpandedType(SwiftAggLowering &lowering, bool forReturn, CharUnits alignmentForIndirect)
unsigned getBitWidthValue(const ASTContext &Ctx) const
Definition: Decl.cpp:3633
static ABIArgInfo getExpand()
static bool areBytesInSameUnit(CharUnits first, CharUnits second, CharUnits chunkSize)
CanQualType getReturnType() const
static CharUnits One()
One - Construct a CharUnits quantity of one.
Definition: CharUnits.h:58
static llvm::Type * getCommonType(llvm::Type *first, llvm::Type *second)
Given two types with the same size, try to find a common type.
const TargetCodeGenInfo & getTargetCodeGenInfo()
CharUnits getNaturalAlignment(CodeGenModule &CGM, llvm::Type *type)
Return the Swift CC&#39;s notion of the natural alignment of a type.
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:179
ASTRecordLayout - This class contains layout information for one RecordDecl, which is a struct/union/...
Definition: RecordLayout.h:39
void addOpaqueData(CharUnits begin, CharUnits end)
SourceLocation End
std::pair< llvm::StructType *, llvm::Type * > getCoerceAndExpandTypes() const
Return the types for a coerce-and-expand operation.
bool isSwiftErrorLoweredInRegister(CodeGenModule &CGM)
Is swifterror lowered to a register by the target ABI.
CharUnits getTypeAlignInChars(QualType T) const
Return the ABI-specified alignment of a (complete) type T, in characters.
SourceLocation Begin
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
char __ovld __cnfn min(char x, char y)
Returns y if y < x, otherwise it returns x.
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
bool hasNonTrivialDestructor() const
Determine whether this class has a non-trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1410
CharUnits getVBPtrOffset() const
getVBPtrOffset - Get the offset for virtual base table pointer.
Definition: RecordLayout.h:296
ASTContext & getContext() const
The l-value was considered opaque, so the alignment was determined from a type.
uint64_t getFieldOffset(unsigned FieldNo) const
getFieldOffset - Get the offset of the given field index, in bits.
Definition: RecordLayout.h:181
bool empty() const
Does this lowering require passing any data?
void addTypedData(QualType type, CharUnits begin)
static CharUnits getTypeStoreSize(CodeGenModule &CGM, llvm::Type *type)
void computeABIInfo(CodeGenModule &CGM, CGFunctionInfo &FI)
Compute the ABI information of a swiftcall function.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2321
static const SwiftABIInfo & getSwiftABIInfo(CodeGenModule &CGM)
static CharUnits getOffsetAtStartOfUnit(CharUnits offset, CharUnits unitSize)
Given a power-of-two unit size, return the offset of the aligned unit of that size which contains the...
bool shouldPassCXXRecordIndirectly(CodeGenModule &CGM, const CXXRecordDecl *record)
Should a C++ record type be passed and returned indirectly?
void legalizeVectorType(CodeGenModule &CGM, CharUnits vectorSize, llvm::VectorType *vectorTy, llvm::SmallVectorImpl< llvm::Type *> &types)
Turn a vector type in a sequence of legal component vector types.
CGFunctionInfo - Class to encapsulate the information about a function definition.
This class organizes the cross-function state that is used while generating LLVM code.
Dataflow Directional Tag Classes.
void enumerateComponents(EnumerationCallback callback) const
Enumerate the expanded components of this type.
bool isLegalVectorType(CodeGenModule &CGM, CharUnits vectorSize, llvm::VectorType *vectorTy)
Is the given vector type "legal" for Swift&#39;s perspective on the current platform? ...
A refining implementation of ABIInfo for targets that support swiftcall.
Definition: ABIInfo.h:134
A pointer to member type per C++ 8.3.3 - Pointers to members.
Definition: Type.h:2504
virtual bool isLegalVectorTypeForSwift(CharUnits totalSize, llvm::Type *eltTy, unsigned elts) const
Definition: TargetInfo.cpp:132
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:3978
Complex values, per C99 6.2.5p11.
Definition: Type.h:2225
virtual bool hasInt128Type() const
Determine whether the __int128 type is supported on this target.
Definition: TargetInfo.h:360
CharUnits toCharUnitsFromBits(int64_t BitSize) const
Convert a size in bits to a size in characters.
bool isMultipleOf(CharUnits N) const
Test whether this is a multiple of the other value.
Definition: CharUnits.h:137
int64_t toBits(CharUnits CharSize) const
Convert a size in characters to a size in bits.
static ABIArgInfo getCoerceAndExpand(llvm::StructType *coerceToType, llvm::Type *unpaddedCoerceToType)
Represents a C++ struct/union/class.
Definition: DeclCXX.h:299
bool isLegalIntegerType(CodeGenModule &CGM, llvm::IntegerType *type)
Is the given integer type "legal" for Swift&#39;s perspective on the current platform?
Defines the clang::TargetInfo interface.
bool isUnion() const
Definition: Decl.h:3159
CharUnits getTypeSizeInChars(QualType T) const
Return the size of the specified (complete) type T, in characters.
CharUnits getMaximumVoluntaryIntegerSize(CodeGenModule &CGM)
Return the maximum voluntary integer size for the current target.
bool hasOwnVBPtr() const
hasOwnVBPtr - Does this class provide its own virtual-base table pointer, rather than inheriting one ...
Definition: RecordLayout.h:270
ctor_range ctors() const
Definition: DeclCXX.h:835
static ABIArgInfo getIndirect(CharUnits Alignment, bool ByVal=true, bool Realign=false, llvm::Type *Padding=nullptr)
bool shouldPassIndirectly(bool asReturnValue) const
According to the target Swift ABI, should a value with this lowering be passed indirectly?