1 //===- DebugInfoMetadata.cpp - Implement debug info metadata --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the debug info Metadata classes.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/IR/DebugInfoMetadata.h"
14 #include "LLVMContextImpl.h"
15 #include "MetadataImpl.h"
16 #include "llvm/ADT/SmallSet.h"
17 #include "llvm/ADT/StringSwitch.h"
18 #include "llvm/IR/DIBuilder.h"
19 #include "llvm/IR/Function.h"
20 #include "llvm/IR/Instructions.h"
21 
22 #include <numeric>
23 
24 using namespace llvm;
25 
26 const DIExpression::FragmentInfo DebugVariable::DefaultFragment = {
27     std::numeric_limits<uint64_t>::max(), std::numeric_limits<uint64_t>::min()};
28 
29 DILocation::DILocation(LLVMContext &C, StorageType Storage, unsigned Line,
30                        unsigned Column, ArrayRef<Metadata *> MDs,
31                        bool ImplicitCode)
32     : MDNode(C, DILocationKind, Storage, MDs) {
33   assert((MDs.size() == 1 || MDs.size() == 2) &&
34          "Expected a scope and optional inlined-at");
35 
36   // Set line and column.
37   assert(Column < (1u << 16) && "Expected 16-bit column");
38 
39   SubclassData32 = Line;
40   SubclassData16 = Column;
41 
42   setImplicitCode(ImplicitCode);
43 }
44 
45 static void adjustColumn(unsigned &Column) {
46   // Set to unknown on overflow.  We only have 16 bits to play with here.
47   if (Column >= (1u << 16))
48     Column = 0;
49 }
50 
51 DILocation *DILocation::getImpl(LLVMContext &Context, unsigned Line,
52                                 unsigned Column, Metadata *Scope,
53                                 Metadata *InlinedAt, bool ImplicitCode,
54                                 StorageType Storage, bool ShouldCreate) {
55   // Fixup column.
56   adjustColumn(Column);
57 
58   if (Storage == Uniqued) {
59     if (auto *N = getUniqued(Context.pImpl->DILocations,
60                              DILocationInfo::KeyTy(Line, Column, Scope,
61                                                    InlinedAt, ImplicitCode)))
62       return N;
63     if (!ShouldCreate)
64       return nullptr;
65   } else {
66     assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
67   }
68 
69   SmallVector<Metadata *, 2> Ops;
70   Ops.push_back(Scope);
71   if (InlinedAt)
72     Ops.push_back(InlinedAt);
73   return storeImpl(new (Ops.size()) DILocation(Context, Storage, Line, Column,
74                                                Ops, ImplicitCode),
75                    Storage, Context.pImpl->DILocations);
76 }
77 
78 const
79 DILocation *DILocation::getMergedLocations(ArrayRef<const DILocation *> Locs) {
80   if (Locs.empty())
81     return nullptr;
82   if (Locs.size() == 1)
83     return Locs[0];
84   auto *Merged = Locs[0];
85   for (const DILocation *L : llvm::drop_begin(Locs)) {
86     Merged = getMergedLocation(Merged, L);
87     if (Merged == nullptr)
88       break;
89   }
90   return Merged;
91 }
92 
93 const DILocation *DILocation::getMergedLocation(const DILocation *LocA,
94                                                 const DILocation *LocB) {
95   if (!LocA || !LocB)
96     return nullptr;
97 
98   if (LocA == LocB)
99     return LocA;
100 
101   SmallPtrSet<DILocation *, 5> InlinedLocationsA;
102   for (DILocation *L = LocA->getInlinedAt(); L; L = L->getInlinedAt())
103     InlinedLocationsA.insert(L);
104   SmallSet<std::pair<DIScope *, DILocation *>, 5> Locations;
105   DIScope *S = LocA->getScope();
106   DILocation *L = LocA->getInlinedAt();
107   while (S) {
108     Locations.insert(std::make_pair(S, L));
109     S = S->getScope();
110     if (!S && L) {
111       S = L->getScope();
112       L = L->getInlinedAt();
113     }
114   }
115   const DILocation *Result = LocB;
116   S = LocB->getScope();
117   L = LocB->getInlinedAt();
118   while (S) {
119     if (Locations.count(std::make_pair(S, L)))
120       break;
121     S = S->getScope();
122     if (!S && L) {
123       S = L->getScope();
124       L = L->getInlinedAt();
125     }
126   }
127 
128   // If the two locations are irreconsilable, just pick one. This is misleading,
129   // but on the other hand, it's a "line 0" location.
130   if (!S || !isa<DILocalScope>(S))
131     S = LocA->getScope();
132   return DILocation::get(Result->getContext(), 0, 0, S, L);
133 }
134 
135 Optional<unsigned> DILocation::encodeDiscriminator(unsigned BD, unsigned DF, unsigned CI) {
136   std::array<unsigned, 3> Components = {BD, DF, CI};
137   uint64_t RemainingWork = 0U;
138   // We use RemainingWork to figure out if we have no remaining components to
139   // encode. For example: if BD != 0 but DF == 0 && CI == 0, we don't need to
140   // encode anything for the latter 2.
141   // Since any of the input components is at most 32 bits, their sum will be
142   // less than 34 bits, and thus RemainingWork won't overflow.
143   RemainingWork = std::accumulate(Components.begin(), Components.end(), RemainingWork);
144 
145   int I = 0;
146   unsigned Ret = 0;
147   unsigned NextBitInsertionIndex = 0;
148   while (RemainingWork > 0) {
149     unsigned C = Components[I++];
150     RemainingWork -= C;
151     unsigned EC = encodeComponent(C);
152     Ret |= (EC << NextBitInsertionIndex);
153     NextBitInsertionIndex += encodingBits(C);
154   }
155 
156   // Encoding may be unsuccessful because of overflow. We determine success by
157   // checking equivalence of components before & after encoding. Alternatively,
158   // we could determine Success during encoding, but the current alternative is
159   // simpler.
160   unsigned TBD, TDF, TCI = 0;
161   decodeDiscriminator(Ret, TBD, TDF, TCI);
162   if (TBD == BD && TDF == DF && TCI == CI)
163     return Ret;
164   return None;
165 }
166 
167 void DILocation::decodeDiscriminator(unsigned D, unsigned &BD, unsigned &DF,
168                                      unsigned &CI) {
169   BD = getUnsignedFromPrefixEncoding(D);
170   DF = getUnsignedFromPrefixEncoding(getNextComponentInDiscriminator(D));
171   CI = getUnsignedFromPrefixEncoding(
172       getNextComponentInDiscriminator(getNextComponentInDiscriminator(D)));
173 }
174 
175 
176 DINode::DIFlags DINode::getFlag(StringRef Flag) {
177   return StringSwitch<DIFlags>(Flag)
178 #define HANDLE_DI_FLAG(ID, NAME) .Case("DIFlag" #NAME, Flag##NAME)
179 #include "llvm/IR/DebugInfoFlags.def"
180       .Default(DINode::FlagZero);
181 }
182 
183 StringRef DINode::getFlagString(DIFlags Flag) {
184   switch (Flag) {
185 #define HANDLE_DI_FLAG(ID, NAME)                                               \
186   case Flag##NAME:                                                             \
187     return "DIFlag" #NAME;
188 #include "llvm/IR/DebugInfoFlags.def"
189   }
190   return "";
191 }
192 
193 DINode::DIFlags DINode::splitFlags(DIFlags Flags,
194                                    SmallVectorImpl<DIFlags> &SplitFlags) {
195   // Flags that are packed together need to be specially handled, so
196   // that, for example, we emit "DIFlagPublic" and not
197   // "DIFlagPrivate | DIFlagProtected".
198   if (DIFlags A = Flags & FlagAccessibility) {
199     if (A == FlagPrivate)
200       SplitFlags.push_back(FlagPrivate);
201     else if (A == FlagProtected)
202       SplitFlags.push_back(FlagProtected);
203     else
204       SplitFlags.push_back(FlagPublic);
205     Flags &= ~A;
206   }
207   if (DIFlags R = Flags & FlagPtrToMemberRep) {
208     if (R == FlagSingleInheritance)
209       SplitFlags.push_back(FlagSingleInheritance);
210     else if (R == FlagMultipleInheritance)
211       SplitFlags.push_back(FlagMultipleInheritance);
212     else
213       SplitFlags.push_back(FlagVirtualInheritance);
214     Flags &= ~R;
215   }
216   if ((Flags & FlagIndirectVirtualBase) == FlagIndirectVirtualBase) {
217     Flags &= ~FlagIndirectVirtualBase;
218     SplitFlags.push_back(FlagIndirectVirtualBase);
219   }
220 
221 #define HANDLE_DI_FLAG(ID, NAME)                                               \
222   if (DIFlags Bit = Flags & Flag##NAME) {                                      \
223     SplitFlags.push_back(Bit);                                                 \
224     Flags &= ~Bit;                                                             \
225   }
226 #include "llvm/IR/DebugInfoFlags.def"
227   return Flags;
228 }
229 
230 DIScope *DIScope::getScope() const {
231   if (auto *T = dyn_cast<DIType>(this))
232     return T->getScope();
233 
234   if (auto *SP = dyn_cast<DISubprogram>(this))
235     return SP->getScope();
236 
237   if (auto *LB = dyn_cast<DILexicalBlockBase>(this))
238     return LB->getScope();
239 
240   if (auto *NS = dyn_cast<DINamespace>(this))
241     return NS->getScope();
242 
243   if (auto *CB = dyn_cast<DICommonBlock>(this))
244     return CB->getScope();
245 
246   if (auto *M = dyn_cast<DIModule>(this))
247     return M->getScope();
248 
249   assert((isa<DIFile>(this) || isa<DICompileUnit>(this)) &&
250          "Unhandled type of scope.");
251   return nullptr;
252 }
253 
254 StringRef DIScope::getName() const {
255   if (auto *T = dyn_cast<DIType>(this))
256     return T->getName();
257   if (auto *SP = dyn_cast<DISubprogram>(this))
258     return SP->getName();
259   if (auto *NS = dyn_cast<DINamespace>(this))
260     return NS->getName();
261   if (auto *CB = dyn_cast<DICommonBlock>(this))
262     return CB->getName();
263   if (auto *M = dyn_cast<DIModule>(this))
264     return M->getName();
265   assert((isa<DILexicalBlockBase>(this) || isa<DIFile>(this) ||
266           isa<DICompileUnit>(this)) &&
267          "Unhandled type of scope.");
268   return "";
269 }
270 
271 #ifndef NDEBUG
272 static bool isCanonical(const MDString *S) {
273   return !S || !S->getString().empty();
274 }
275 #endif
276 
277 GenericDINode *GenericDINode::getImpl(LLVMContext &Context, unsigned Tag,
278                                       MDString *Header,
279                                       ArrayRef<Metadata *> DwarfOps,
280                                       StorageType Storage, bool ShouldCreate) {
281   unsigned Hash = 0;
282   if (Storage == Uniqued) {
283     GenericDINodeInfo::KeyTy Key(Tag, Header, DwarfOps);
284     if (auto *N = getUniqued(Context.pImpl->GenericDINodes, Key))
285       return N;
286     if (!ShouldCreate)
287       return nullptr;
288     Hash = Key.getHash();
289   } else {
290     assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
291   }
292 
293   // Use a nullptr for empty headers.
294   assert(isCanonical(Header) && "Expected canonical MDString");
295   Metadata *PreOps[] = {Header};
296   return storeImpl(new (DwarfOps.size() + 1) GenericDINode(
297                        Context, Storage, Hash, Tag, PreOps, DwarfOps),
298                    Storage, Context.pImpl->GenericDINodes);
299 }
300 
301 void GenericDINode::recalculateHash() {
302   setHash(GenericDINodeInfo::KeyTy::calculateHash(this));
303 }
304 
305 #define UNWRAP_ARGS_IMPL(...) __VA_ARGS__
306 #define UNWRAP_ARGS(ARGS) UNWRAP_ARGS_IMPL ARGS
307 #define DEFINE_GETIMPL_LOOKUP(CLASS, ARGS)                                     \
308   do {                                                                         \
309     if (Storage == Uniqued) {                                                  \
310       if (auto *N = getUniqued(Context.pImpl->CLASS##s,                        \
311                                CLASS##Info::KeyTy(UNWRAP_ARGS(ARGS))))         \
312         return N;                                                              \
313       if (!ShouldCreate)                                                       \
314         return nullptr;                                                        \
315     } else {                                                                   \
316       assert(ShouldCreate &&                                                   \
317              "Expected non-uniqued nodes to always be created");               \
318     }                                                                          \
319   } while (false)
320 #define DEFINE_GETIMPL_STORE(CLASS, ARGS, OPS)                                 \
321   return storeImpl(new (array_lengthof(OPS))                                   \
322                        CLASS(Context, Storage, UNWRAP_ARGS(ARGS), OPS),        \
323                    Storage, Context.pImpl->CLASS##s)
324 #define DEFINE_GETIMPL_STORE_NO_OPS(CLASS, ARGS)                               \
325   return storeImpl(new (0u) CLASS(Context, Storage, UNWRAP_ARGS(ARGS)),        \
326                    Storage, Context.pImpl->CLASS##s)
327 #define DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(CLASS, OPS)                   \
328   return storeImpl(new (array_lengthof(OPS)) CLASS(Context, Storage, OPS),     \
329                    Storage, Context.pImpl->CLASS##s)
330 #define DEFINE_GETIMPL_STORE_N(CLASS, ARGS, OPS, NUM_OPS)                      \
331   return storeImpl(new (NUM_OPS)                                               \
332                        CLASS(Context, Storage, UNWRAP_ARGS(ARGS), OPS),        \
333                    Storage, Context.pImpl->CLASS##s)
334 
335 DISubrange *DISubrange::getImpl(LLVMContext &Context, int64_t Count, int64_t Lo,
336                                 StorageType Storage, bool ShouldCreate) {
337   auto *CountNode = ConstantAsMetadata::get(
338       ConstantInt::getSigned(Type::getInt64Ty(Context), Count));
339   auto *LB = ConstantAsMetadata::get(
340       ConstantInt::getSigned(Type::getInt64Ty(Context), Lo));
341   return getImpl(Context, CountNode, LB, nullptr, nullptr, Storage,
342                  ShouldCreate);
343 }
344 
345 DISubrange *DISubrange::getImpl(LLVMContext &Context, Metadata *CountNode,
346                                 int64_t Lo, StorageType Storage,
347                                 bool ShouldCreate) {
348   auto *LB = ConstantAsMetadata::get(
349       ConstantInt::getSigned(Type::getInt64Ty(Context), Lo));
350   return getImpl(Context, CountNode, LB, nullptr, nullptr, Storage,
351                  ShouldCreate);
352 }
353 
354 DISubrange *DISubrange::getImpl(LLVMContext &Context, Metadata *CountNode,
355                                 Metadata *LB, Metadata *UB, Metadata *Stride,
356                                 StorageType Storage, bool ShouldCreate) {
357   DEFINE_GETIMPL_LOOKUP(DISubrange, (CountNode, LB, UB, Stride));
358   Metadata *Ops[] = {CountNode, LB, UB, Stride};
359   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DISubrange, Ops);
360 }
361 
362 DISubrange::CountType DISubrange::getCount() const {
363   if (!getRawCountNode())
364     return CountType();
365 
366   if (auto *MD = dyn_cast<ConstantAsMetadata>(getRawCountNode()))
367     return CountType(cast<ConstantInt>(MD->getValue()));
368 
369   if (auto *DV = dyn_cast<DIVariable>(getRawCountNode()))
370     return CountType(DV);
371 
372   return CountType();
373 }
374 
375 DISubrange::BoundType DISubrange::getLowerBound() const {
376   Metadata *LB = getRawLowerBound();
377   if (!LB)
378     return BoundType();
379 
380   assert((isa<ConstantAsMetadata>(LB) || isa<DIVariable>(LB) ||
381           isa<DIExpression>(LB)) &&
382          "LowerBound must be signed constant or DIVariable or DIExpression");
383 
384   if (auto *MD = dyn_cast<ConstantAsMetadata>(LB))
385     return BoundType(cast<ConstantInt>(MD->getValue()));
386 
387   if (auto *MD = dyn_cast<DIVariable>(LB))
388     return BoundType(MD);
389 
390   if (auto *MD = dyn_cast<DIExpression>(LB))
391     return BoundType(MD);
392 
393   return BoundType();
394 }
395 
396 DISubrange::BoundType DISubrange::getUpperBound() const {
397   Metadata *UB = getRawUpperBound();
398   if (!UB)
399     return BoundType();
400 
401   assert((isa<ConstantAsMetadata>(UB) || isa<DIVariable>(UB) ||
402           isa<DIExpression>(UB)) &&
403          "UpperBound must be signed constant or DIVariable or DIExpression");
404 
405   if (auto *MD = dyn_cast<ConstantAsMetadata>(UB))
406     return BoundType(cast<ConstantInt>(MD->getValue()));
407 
408   if (auto *MD = dyn_cast<DIVariable>(UB))
409     return BoundType(MD);
410 
411   if (auto *MD = dyn_cast<DIExpression>(UB))
412     return BoundType(MD);
413 
414   return BoundType();
415 }
416 
417 DISubrange::BoundType DISubrange::getStride() const {
418   Metadata *ST = getRawStride();
419   if (!ST)
420     return BoundType();
421 
422   assert((isa<ConstantAsMetadata>(ST) || isa<DIVariable>(ST) ||
423           isa<DIExpression>(ST)) &&
424          "Stride must be signed constant or DIVariable or DIExpression");
425 
426   if (auto *MD = dyn_cast<ConstantAsMetadata>(ST))
427     return BoundType(cast<ConstantInt>(MD->getValue()));
428 
429   if (auto *MD = dyn_cast<DIVariable>(ST))
430     return BoundType(MD);
431 
432   if (auto *MD = dyn_cast<DIExpression>(ST))
433     return BoundType(MD);
434 
435   return BoundType();
436 }
437 
438 DIGenericSubrange *DIGenericSubrange::getImpl(LLVMContext &Context,
439                                               Metadata *CountNode, Metadata *LB,
440                                               Metadata *UB, Metadata *Stride,
441                                               StorageType Storage,
442                                               bool ShouldCreate) {
443   DEFINE_GETIMPL_LOOKUP(DIGenericSubrange, (CountNode, LB, UB, Stride));
444   Metadata *Ops[] = {CountNode, LB, UB, Stride};
445   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIGenericSubrange, Ops);
446 }
447 
448 DIGenericSubrange::BoundType DIGenericSubrange::getCount() const {
449   Metadata *CB = getRawCountNode();
450   if (!CB)
451     return BoundType();
452 
453   assert((isa<DIVariable>(CB) || isa<DIExpression>(CB)) &&
454          "Count must be signed constant or DIVariable or DIExpression");
455 
456   if (auto *MD = dyn_cast<DIVariable>(CB))
457     return BoundType(MD);
458 
459   if (auto *MD = dyn_cast<DIExpression>(CB))
460     return BoundType(MD);
461 
462   return BoundType();
463 }
464 
465 DIGenericSubrange::BoundType DIGenericSubrange::getLowerBound() const {
466   Metadata *LB = getRawLowerBound();
467   if (!LB)
468     return BoundType();
469 
470   assert((isa<DIVariable>(LB) || isa<DIExpression>(LB)) &&
471          "LowerBound must be signed constant or DIVariable or DIExpression");
472 
473   if (auto *MD = dyn_cast<DIVariable>(LB))
474     return BoundType(MD);
475 
476   if (auto *MD = dyn_cast<DIExpression>(LB))
477     return BoundType(MD);
478 
479   return BoundType();
480 }
481 
482 DIGenericSubrange::BoundType DIGenericSubrange::getUpperBound() const {
483   Metadata *UB = getRawUpperBound();
484   if (!UB)
485     return BoundType();
486 
487   assert((isa<DIVariable>(UB) || isa<DIExpression>(UB)) &&
488          "UpperBound must be signed constant or DIVariable or DIExpression");
489 
490   if (auto *MD = dyn_cast<DIVariable>(UB))
491     return BoundType(MD);
492 
493   if (auto *MD = dyn_cast<DIExpression>(UB))
494     return BoundType(MD);
495 
496   return BoundType();
497 }
498 
499 DIGenericSubrange::BoundType DIGenericSubrange::getStride() const {
500   Metadata *ST = getRawStride();
501   if (!ST)
502     return BoundType();
503 
504   assert((isa<DIVariable>(ST) || isa<DIExpression>(ST)) &&
505          "Stride must be signed constant or DIVariable or DIExpression");
506 
507   if (auto *MD = dyn_cast<DIVariable>(ST))
508     return BoundType(MD);
509 
510   if (auto *MD = dyn_cast<DIExpression>(ST))
511     return BoundType(MD);
512 
513   return BoundType();
514 }
515 
516 DIEnumerator *DIEnumerator::getImpl(LLVMContext &Context, const APInt &Value,
517                                     bool IsUnsigned, MDString *Name,
518                                     StorageType Storage, bool ShouldCreate) {
519   assert(isCanonical(Name) && "Expected canonical MDString");
520   DEFINE_GETIMPL_LOOKUP(DIEnumerator, (Value, IsUnsigned, Name));
521   Metadata *Ops[] = {Name};
522   DEFINE_GETIMPL_STORE(DIEnumerator, (Value, IsUnsigned), Ops);
523 }
524 
525 DIBasicType *DIBasicType::getImpl(LLVMContext &Context, unsigned Tag,
526                                   MDString *Name, uint64_t SizeInBits,
527                                   uint32_t AlignInBits, unsigned Encoding,
528                                   DIFlags Flags, StorageType Storage,
529                                   bool ShouldCreate) {
530   assert(isCanonical(Name) && "Expected canonical MDString");
531   DEFINE_GETIMPL_LOOKUP(DIBasicType,
532                         (Tag, Name, SizeInBits, AlignInBits, Encoding, Flags));
533   Metadata *Ops[] = {nullptr, nullptr, Name};
534   DEFINE_GETIMPL_STORE(DIBasicType, (Tag, SizeInBits, AlignInBits, Encoding,
535                       Flags), Ops);
536 }
537 
538 Optional<DIBasicType::Signedness> DIBasicType::getSignedness() const {
539   switch (getEncoding()) {
540   case dwarf::DW_ATE_signed:
541   case dwarf::DW_ATE_signed_char:
542     return Signedness::Signed;
543   case dwarf::DW_ATE_unsigned:
544   case dwarf::DW_ATE_unsigned_char:
545     return Signedness::Unsigned;
546   default:
547     return None;
548   }
549 }
550 
551 DIStringType *DIStringType::getImpl(LLVMContext &Context, unsigned Tag,
552                                     MDString *Name, Metadata *StringLength,
553                                     Metadata *StringLengthExp,
554                                     uint64_t SizeInBits, uint32_t AlignInBits,
555                                     unsigned Encoding, StorageType Storage,
556                                     bool ShouldCreate) {
557   assert(isCanonical(Name) && "Expected canonical MDString");
558   DEFINE_GETIMPL_LOOKUP(DIStringType, (Tag, Name, StringLength, StringLengthExp,
559                                        SizeInBits, AlignInBits, Encoding));
560   Metadata *Ops[] = {nullptr, nullptr, Name, StringLength, StringLengthExp};
561   DEFINE_GETIMPL_STORE(DIStringType, (Tag, SizeInBits, AlignInBits, Encoding),
562                        Ops);
563 }
564 
565 DIDerivedType *DIDerivedType::getImpl(
566     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
567     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
568     uint32_t AlignInBits, uint64_t OffsetInBits,
569     Optional<unsigned> DWARFAddressSpace, DIFlags Flags, Metadata *ExtraData,
570     StorageType Storage, bool ShouldCreate) {
571   assert(isCanonical(Name) && "Expected canonical MDString");
572   DEFINE_GETIMPL_LOOKUP(DIDerivedType,
573                         (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
574                          AlignInBits, OffsetInBits, DWARFAddressSpace, Flags,
575                          ExtraData));
576   Metadata *Ops[] = {File, Scope, Name, BaseType, ExtraData};
577   DEFINE_GETIMPL_STORE(
578       DIDerivedType, (Tag, Line, SizeInBits, AlignInBits, OffsetInBits,
579                       DWARFAddressSpace, Flags), Ops);
580 }
581 
582 DICompositeType *DICompositeType::getImpl(
583     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
584     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
585     uint32_t AlignInBits, uint64_t OffsetInBits, DIFlags Flags,
586     Metadata *Elements, unsigned RuntimeLang, Metadata *VTableHolder,
587     Metadata *TemplateParams, MDString *Identifier, Metadata *Discriminator,
588     Metadata *DataLocation, Metadata *Associated, Metadata *Allocated,
589     Metadata *Rank, StorageType Storage, bool ShouldCreate) {
590   assert(isCanonical(Name) && "Expected canonical MDString");
591 
592   // Keep this in sync with buildODRType.
593   DEFINE_GETIMPL_LOOKUP(
594       DICompositeType,
595       (Tag, Name, File, Line, Scope, BaseType, SizeInBits, AlignInBits,
596        OffsetInBits, Flags, Elements, RuntimeLang, VTableHolder, TemplateParams,
597        Identifier, Discriminator, DataLocation, Associated, Allocated, Rank));
598   Metadata *Ops[] = {File,          Scope,        Name,           BaseType,
599                      Elements,      VTableHolder, TemplateParams, Identifier,
600                      Discriminator, DataLocation, Associated,     Allocated,
601                      Rank};
602   DEFINE_GETIMPL_STORE(DICompositeType, (Tag, Line, RuntimeLang, SizeInBits,
603                                          AlignInBits, OffsetInBits, Flags),
604                        Ops);
605 }
606 
607 DICompositeType *DICompositeType::buildODRType(
608     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
609     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
610     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
611     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
612     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator,
613     Metadata *DataLocation, Metadata *Associated, Metadata *Allocated,
614     Metadata *Rank) {
615   assert(!Identifier.getString().empty() && "Expected valid identifier");
616   if (!Context.isODRUniquingDebugTypes())
617     return nullptr;
618   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
619   if (!CT)
620     return CT = DICompositeType::getDistinct(
621                Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
622                AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
623                VTableHolder, TemplateParams, &Identifier, Discriminator,
624                DataLocation, Associated, Allocated, Rank);
625 
626   // Only mutate CT if it's a forward declaration and the new operands aren't.
627   assert(CT->getRawIdentifier() == &Identifier && "Wrong ODR identifier?");
628   if (!CT->isForwardDecl() || (Flags & DINode::FlagFwdDecl))
629     return CT;
630 
631   // Mutate CT in place.  Keep this in sync with getImpl.
632   CT->mutate(Tag, Line, RuntimeLang, SizeInBits, AlignInBits, OffsetInBits,
633              Flags);
634   Metadata *Ops[] = {File,          Scope,        Name,           BaseType,
635                      Elements,      VTableHolder, TemplateParams, &Identifier,
636                      Discriminator, DataLocation, Associated,     Allocated,
637                      Rank};
638   assert((std::end(Ops) - std::begin(Ops)) == (int)CT->getNumOperands() &&
639          "Mismatched number of operands");
640   for (unsigned I = 0, E = CT->getNumOperands(); I != E; ++I)
641     if (Ops[I] != CT->getOperand(I))
642       CT->setOperand(I, Ops[I]);
643   return CT;
644 }
645 
646 DICompositeType *DICompositeType::getODRType(
647     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
648     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
649     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
650     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
651     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator,
652     Metadata *DataLocation, Metadata *Associated, Metadata *Allocated,
653     Metadata *Rank) {
654   assert(!Identifier.getString().empty() && "Expected valid identifier");
655   if (!Context.isODRUniquingDebugTypes())
656     return nullptr;
657   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
658   if (!CT)
659     CT = DICompositeType::getDistinct(
660         Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
661         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang, VTableHolder,
662         TemplateParams, &Identifier, Discriminator, DataLocation, Associated,
663         Allocated, Rank);
664   return CT;
665 }
666 
667 DICompositeType *DICompositeType::getODRTypeIfExists(LLVMContext &Context,
668                                                      MDString &Identifier) {
669   assert(!Identifier.getString().empty() && "Expected valid identifier");
670   if (!Context.isODRUniquingDebugTypes())
671     return nullptr;
672   return Context.pImpl->DITypeMap->lookup(&Identifier);
673 }
674 
675 DISubroutineType *DISubroutineType::getImpl(LLVMContext &Context, DIFlags Flags,
676                                             uint8_t CC, Metadata *TypeArray,
677                                             StorageType Storage,
678                                             bool ShouldCreate) {
679   DEFINE_GETIMPL_LOOKUP(DISubroutineType, (Flags, CC, TypeArray));
680   Metadata *Ops[] = {nullptr, nullptr, nullptr, TypeArray};
681   DEFINE_GETIMPL_STORE(DISubroutineType, (Flags, CC), Ops);
682 }
683 
684 // FIXME: Implement this string-enum correspondence with a .def file and macros,
685 // so that the association is explicit rather than implied.
686 static const char *ChecksumKindName[DIFile::CSK_Last] = {
687     "CSK_MD5",
688     "CSK_SHA1",
689     "CSK_SHA256",
690 };
691 
692 StringRef DIFile::getChecksumKindAsString(ChecksumKind CSKind) {
693   assert(CSKind <= DIFile::CSK_Last && "Invalid checksum kind");
694   // The first space was originally the CSK_None variant, which is now
695   // obsolete, but the space is still reserved in ChecksumKind, so we account
696   // for it here.
697   return ChecksumKindName[CSKind - 1];
698 }
699 
700 Optional<DIFile::ChecksumKind> DIFile::getChecksumKind(StringRef CSKindStr) {
701   return StringSwitch<Optional<DIFile::ChecksumKind>>(CSKindStr)
702       .Case("CSK_MD5", DIFile::CSK_MD5)
703       .Case("CSK_SHA1", DIFile::CSK_SHA1)
704       .Case("CSK_SHA256", DIFile::CSK_SHA256)
705       .Default(None);
706 }
707 
708 DIFile *DIFile::getImpl(LLVMContext &Context, MDString *Filename,
709                         MDString *Directory,
710                         Optional<DIFile::ChecksumInfo<MDString *>> CS,
711                         Optional<MDString *> Source, StorageType Storage,
712                         bool ShouldCreate) {
713   assert(isCanonical(Filename) && "Expected canonical MDString");
714   assert(isCanonical(Directory) && "Expected canonical MDString");
715   assert((!CS || isCanonical(CS->Value)) && "Expected canonical MDString");
716   assert((!Source || isCanonical(*Source)) && "Expected canonical MDString");
717   DEFINE_GETIMPL_LOOKUP(DIFile, (Filename, Directory, CS, Source));
718   Metadata *Ops[] = {Filename, Directory, CS ? CS->Value : nullptr,
719                      Source.getValueOr(nullptr)};
720   DEFINE_GETIMPL_STORE(DIFile, (CS, Source), Ops);
721 }
722 
723 DICompileUnit *DICompileUnit::getImpl(
724     LLVMContext &Context, unsigned SourceLanguage, Metadata *File,
725     MDString *Producer, bool IsOptimized, MDString *Flags,
726     unsigned RuntimeVersion, MDString *SplitDebugFilename,
727     unsigned EmissionKind, Metadata *EnumTypes, Metadata *RetainedTypes,
728     Metadata *GlobalVariables, Metadata *ImportedEntities, Metadata *Macros,
729     uint64_t DWOId, bool SplitDebugInlining, bool DebugInfoForProfiling,
730     unsigned NameTableKind, bool RangesBaseAddress, MDString *SysRoot,
731     MDString *SDK, StorageType Storage, bool ShouldCreate) {
732   assert(Storage != Uniqued && "Cannot unique DICompileUnit");
733   assert(isCanonical(Producer) && "Expected canonical MDString");
734   assert(isCanonical(Flags) && "Expected canonical MDString");
735   assert(isCanonical(SplitDebugFilename) && "Expected canonical MDString");
736 
737   Metadata *Ops[] = {File,
738                      Producer,
739                      Flags,
740                      SplitDebugFilename,
741                      EnumTypes,
742                      RetainedTypes,
743                      GlobalVariables,
744                      ImportedEntities,
745                      Macros,
746                      SysRoot,
747                      SDK};
748   return storeImpl(new (array_lengthof(Ops)) DICompileUnit(
749                        Context, Storage, SourceLanguage, IsOptimized,
750                        RuntimeVersion, EmissionKind, DWOId, SplitDebugInlining,
751                        DebugInfoForProfiling, NameTableKind, RangesBaseAddress,
752                        Ops),
753                    Storage);
754 }
755 
756 Optional<DICompileUnit::DebugEmissionKind>
757 DICompileUnit::getEmissionKind(StringRef Str) {
758   return StringSwitch<Optional<DebugEmissionKind>>(Str)
759       .Case("NoDebug", NoDebug)
760       .Case("FullDebug", FullDebug)
761       .Case("LineTablesOnly", LineTablesOnly)
762       .Case("DebugDirectivesOnly", DebugDirectivesOnly)
763       .Default(None);
764 }
765 
766 Optional<DICompileUnit::DebugNameTableKind>
767 DICompileUnit::getNameTableKind(StringRef Str) {
768   return StringSwitch<Optional<DebugNameTableKind>>(Str)
769       .Case("Default", DebugNameTableKind::Default)
770       .Case("GNU", DebugNameTableKind::GNU)
771       .Case("None", DebugNameTableKind::None)
772       .Default(None);
773 }
774 
775 const char *DICompileUnit::emissionKindString(DebugEmissionKind EK) {
776   switch (EK) {
777   case NoDebug:        return "NoDebug";
778   case FullDebug:      return "FullDebug";
779   case LineTablesOnly: return "LineTablesOnly";
780   case DebugDirectivesOnly: return "DebugDirectivesOnly";
781   }
782   return nullptr;
783 }
784 
785 const char *DICompileUnit::nameTableKindString(DebugNameTableKind NTK) {
786   switch (NTK) {
787   case DebugNameTableKind::Default:
788     return nullptr;
789   case DebugNameTableKind::GNU:
790     return "GNU";
791   case DebugNameTableKind::None:
792     return "None";
793   }
794   return nullptr;
795 }
796 
797 DISubprogram *DILocalScope::getSubprogram() const {
798   if (auto *Block = dyn_cast<DILexicalBlockBase>(this))
799     return Block->getScope()->getSubprogram();
800   return const_cast<DISubprogram *>(cast<DISubprogram>(this));
801 }
802 
803 DILocalScope *DILocalScope::getNonLexicalBlockFileScope() const {
804   if (auto *File = dyn_cast<DILexicalBlockFile>(this))
805     return File->getScope()->getNonLexicalBlockFileScope();
806   return const_cast<DILocalScope *>(this);
807 }
808 
809 DISubprogram::DISPFlags DISubprogram::getFlag(StringRef Flag) {
810   return StringSwitch<DISPFlags>(Flag)
811 #define HANDLE_DISP_FLAG(ID, NAME) .Case("DISPFlag" #NAME, SPFlag##NAME)
812 #include "llvm/IR/DebugInfoFlags.def"
813       .Default(SPFlagZero);
814 }
815 
816 StringRef DISubprogram::getFlagString(DISPFlags Flag) {
817   switch (Flag) {
818   // Appease a warning.
819   case SPFlagVirtuality:
820     return "";
821 #define HANDLE_DISP_FLAG(ID, NAME)                                             \
822   case SPFlag##NAME:                                                           \
823     return "DISPFlag" #NAME;
824 #include "llvm/IR/DebugInfoFlags.def"
825   }
826   return "";
827 }
828 
829 DISubprogram::DISPFlags
830 DISubprogram::splitFlags(DISPFlags Flags,
831                          SmallVectorImpl<DISPFlags> &SplitFlags) {
832   // Multi-bit fields can require special handling. In our case, however, the
833   // only multi-bit field is virtuality, and all its values happen to be
834   // single-bit values, so the right behavior just falls out.
835 #define HANDLE_DISP_FLAG(ID, NAME)                                             \
836   if (DISPFlags Bit = Flags & SPFlag##NAME) {                                  \
837     SplitFlags.push_back(Bit);                                                 \
838     Flags &= ~Bit;                                                             \
839   }
840 #include "llvm/IR/DebugInfoFlags.def"
841   return Flags;
842 }
843 
844 DISubprogram *DISubprogram::getImpl(
845     LLVMContext &Context, Metadata *Scope, MDString *Name,
846     MDString *LinkageName, Metadata *File, unsigned Line, Metadata *Type,
847     unsigned ScopeLine, Metadata *ContainingType, unsigned VirtualIndex,
848     int ThisAdjustment, DIFlags Flags, DISPFlags SPFlags, Metadata *Unit,
849     Metadata *TemplateParams, Metadata *Declaration, Metadata *RetainedNodes,
850     Metadata *ThrownTypes, StorageType Storage, bool ShouldCreate) {
851   assert(isCanonical(Name) && "Expected canonical MDString");
852   assert(isCanonical(LinkageName) && "Expected canonical MDString");
853   DEFINE_GETIMPL_LOOKUP(DISubprogram,
854                         (Scope, Name, LinkageName, File, Line, Type, ScopeLine,
855                          ContainingType, VirtualIndex, ThisAdjustment, Flags,
856                          SPFlags, Unit, TemplateParams, Declaration,
857                          RetainedNodes, ThrownTypes));
858   SmallVector<Metadata *, 11> Ops = {
859       File,        Scope,         Name,           LinkageName,    Type,       Unit,
860       Declaration, RetainedNodes, ContainingType, TemplateParams, ThrownTypes};
861   if (!ThrownTypes) {
862     Ops.pop_back();
863     if (!TemplateParams) {
864       Ops.pop_back();
865       if (!ContainingType)
866         Ops.pop_back();
867     }
868   }
869   DEFINE_GETIMPL_STORE_N(
870       DISubprogram,
871       (Line, ScopeLine, VirtualIndex, ThisAdjustment, Flags, SPFlags), Ops,
872       Ops.size());
873 }
874 
875 bool DISubprogram::describes(const Function *F) const {
876   assert(F && "Invalid function");
877   return F->getSubprogram() == this;
878 }
879 
880 DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,
881                                         Metadata *File, unsigned Line,
882                                         unsigned Column, StorageType Storage,
883                                         bool ShouldCreate) {
884   // Fixup column.
885   adjustColumn(Column);
886 
887   assert(Scope && "Expected scope");
888   DEFINE_GETIMPL_LOOKUP(DILexicalBlock, (Scope, File, Line, Column));
889   Metadata *Ops[] = {File, Scope};
890   DEFINE_GETIMPL_STORE(DILexicalBlock, (Line, Column), Ops);
891 }
892 
893 DILexicalBlockFile *DILexicalBlockFile::getImpl(LLVMContext &Context,
894                                                 Metadata *Scope, Metadata *File,
895                                                 unsigned Discriminator,
896                                                 StorageType Storage,
897                                                 bool ShouldCreate) {
898   assert(Scope && "Expected scope");
899   DEFINE_GETIMPL_LOOKUP(DILexicalBlockFile, (Scope, File, Discriminator));
900   Metadata *Ops[] = {File, Scope};
901   DEFINE_GETIMPL_STORE(DILexicalBlockFile, (Discriminator), Ops);
902 }
903 
904 DINamespace *DINamespace::getImpl(LLVMContext &Context, Metadata *Scope,
905                                   MDString *Name, bool ExportSymbols,
906                                   StorageType Storage, bool ShouldCreate) {
907   assert(isCanonical(Name) && "Expected canonical MDString");
908   DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, Name, ExportSymbols));
909   // The nullptr is for DIScope's File operand. This should be refactored.
910   Metadata *Ops[] = {nullptr, Scope, Name};
911   DEFINE_GETIMPL_STORE(DINamespace, (ExportSymbols), Ops);
912 }
913 
914 DICommonBlock *DICommonBlock::getImpl(LLVMContext &Context, Metadata *Scope,
915                                       Metadata *Decl, MDString *Name,
916                                       Metadata *File, unsigned LineNo,
917                                       StorageType Storage, bool ShouldCreate) {
918   assert(isCanonical(Name) && "Expected canonical MDString");
919   DEFINE_GETIMPL_LOOKUP(DICommonBlock, (Scope, Decl, Name, File, LineNo));
920   // The nullptr is for DIScope's File operand. This should be refactored.
921   Metadata *Ops[] = {Scope, Decl, Name, File};
922   DEFINE_GETIMPL_STORE(DICommonBlock, (LineNo), Ops);
923 }
924 
925 DIModule *DIModule::getImpl(LLVMContext &Context, Metadata *File,
926                             Metadata *Scope, MDString *Name,
927                             MDString *ConfigurationMacros,
928                             MDString *IncludePath, MDString *APINotesFile,
929                             unsigned LineNo, bool IsDecl, StorageType Storage,
930                             bool ShouldCreate) {
931   assert(isCanonical(Name) && "Expected canonical MDString");
932   DEFINE_GETIMPL_LOOKUP(DIModule, (File, Scope, Name, ConfigurationMacros,
933                                    IncludePath, APINotesFile, LineNo, IsDecl));
934   Metadata *Ops[] = {File,        Scope,       Name, ConfigurationMacros,
935                      IncludePath, APINotesFile};
936   DEFINE_GETIMPL_STORE(DIModule, (LineNo, IsDecl), Ops);
937 }
938 
939 DITemplateTypeParameter *
940 DITemplateTypeParameter::getImpl(LLVMContext &Context, MDString *Name,
941                                  Metadata *Type, bool isDefault,
942                                  StorageType Storage, bool ShouldCreate) {
943   assert(isCanonical(Name) && "Expected canonical MDString");
944   DEFINE_GETIMPL_LOOKUP(DITemplateTypeParameter, (Name, Type, isDefault));
945   Metadata *Ops[] = {Name, Type};
946   DEFINE_GETIMPL_STORE(DITemplateTypeParameter, (isDefault), Ops);
947 }
948 
949 DITemplateValueParameter *DITemplateValueParameter::getImpl(
950     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *Type,
951     bool isDefault, Metadata *Value, StorageType Storage, bool ShouldCreate) {
952   assert(isCanonical(Name) && "Expected canonical MDString");
953   DEFINE_GETIMPL_LOOKUP(DITemplateValueParameter,
954                         (Tag, Name, Type, isDefault, Value));
955   Metadata *Ops[] = {Name, Type, Value};
956   DEFINE_GETIMPL_STORE(DITemplateValueParameter, (Tag, isDefault), Ops);
957 }
958 
959 DIGlobalVariable *
960 DIGlobalVariable::getImpl(LLVMContext &Context, Metadata *Scope, MDString *Name,
961                           MDString *LinkageName, Metadata *File, unsigned Line,
962                           Metadata *Type, bool IsLocalToUnit, bool IsDefinition,
963                           Metadata *StaticDataMemberDeclaration,
964                           Metadata *TemplateParams, uint32_t AlignInBits,
965                           StorageType Storage, bool ShouldCreate) {
966   assert(isCanonical(Name) && "Expected canonical MDString");
967   assert(isCanonical(LinkageName) && "Expected canonical MDString");
968   DEFINE_GETIMPL_LOOKUP(DIGlobalVariable, (Scope, Name, LinkageName, File, Line,
969                                            Type, IsLocalToUnit, IsDefinition,
970                                            StaticDataMemberDeclaration,
971                                            TemplateParams, AlignInBits));
972   Metadata *Ops[] = {Scope,
973                      Name,
974                      File,
975                      Type,
976                      Name,
977                      LinkageName,
978                      StaticDataMemberDeclaration,
979                      TemplateParams};
980   DEFINE_GETIMPL_STORE(DIGlobalVariable,
981                        (Line, IsLocalToUnit, IsDefinition, AlignInBits), Ops);
982 }
983 
984 DILocalVariable *DILocalVariable::getImpl(LLVMContext &Context, Metadata *Scope,
985                                           MDString *Name, Metadata *File,
986                                           unsigned Line, Metadata *Type,
987                                           unsigned Arg, DIFlags Flags,
988                                           uint32_t AlignInBits,
989                                           StorageType Storage,
990                                           bool ShouldCreate) {
991   // 64K ought to be enough for any frontend.
992   assert(Arg <= UINT16_MAX && "Expected argument number to fit in 16-bits");
993 
994   assert(Scope && "Expected scope");
995   assert(isCanonical(Name) && "Expected canonical MDString");
996   DEFINE_GETIMPL_LOOKUP(DILocalVariable,
997                         (Scope, Name, File, Line, Type, Arg, Flags,
998                          AlignInBits));
999   Metadata *Ops[] = {Scope, Name, File, Type};
1000   DEFINE_GETIMPL_STORE(DILocalVariable, (Line, Arg, Flags, AlignInBits), Ops);
1001 }
1002 
1003 Optional<uint64_t> DIVariable::getSizeInBits() const {
1004   // This is used by the Verifier so be mindful of broken types.
1005   const Metadata *RawType = getRawType();
1006   while (RawType) {
1007     // Try to get the size directly.
1008     if (auto *T = dyn_cast<DIType>(RawType))
1009       if (uint64_t Size = T->getSizeInBits())
1010         return Size;
1011 
1012     if (auto *DT = dyn_cast<DIDerivedType>(RawType)) {
1013       // Look at the base type.
1014       RawType = DT->getRawBaseType();
1015       continue;
1016     }
1017 
1018     // Missing type or size.
1019     break;
1020   }
1021 
1022   // Fail gracefully.
1023   return None;
1024 }
1025 
1026 DILabel *DILabel::getImpl(LLVMContext &Context, Metadata *Scope,
1027                           MDString *Name, Metadata *File, unsigned Line,
1028                           StorageType Storage,
1029                           bool ShouldCreate) {
1030   assert(Scope && "Expected scope");
1031   assert(isCanonical(Name) && "Expected canonical MDString");
1032   DEFINE_GETIMPL_LOOKUP(DILabel,
1033                         (Scope, Name, File, Line));
1034   Metadata *Ops[] = {Scope, Name, File};
1035   DEFINE_GETIMPL_STORE(DILabel, (Line), Ops);
1036 }
1037 
1038 DIExpression *DIExpression::getImpl(LLVMContext &Context,
1039                                     ArrayRef<uint64_t> Elements,
1040                                     StorageType Storage, bool ShouldCreate) {
1041   DEFINE_GETIMPL_LOOKUP(DIExpression, (Elements));
1042   DEFINE_GETIMPL_STORE_NO_OPS(DIExpression, (Elements));
1043 }
1044 
1045 unsigned DIExpression::ExprOperand::getSize() const {
1046   uint64_t Op = getOp();
1047 
1048   if (Op >= dwarf::DW_OP_breg0 && Op <= dwarf::DW_OP_breg31)
1049     return 2;
1050 
1051   switch (Op) {
1052   case dwarf::DW_OP_LLVM_convert:
1053   case dwarf::DW_OP_LLVM_fragment:
1054   case dwarf::DW_OP_bregx:
1055     return 3;
1056   case dwarf::DW_OP_constu:
1057   case dwarf::DW_OP_consts:
1058   case dwarf::DW_OP_deref_size:
1059   case dwarf::DW_OP_plus_uconst:
1060   case dwarf::DW_OP_LLVM_tag_offset:
1061   case dwarf::DW_OP_LLVM_entry_value:
1062   case dwarf::DW_OP_LLVM_arg:
1063   case dwarf::DW_OP_regx:
1064     return 2;
1065   default:
1066     return 1;
1067   }
1068 }
1069 
1070 bool DIExpression::isValid() const {
1071   for (auto I = expr_op_begin(), E = expr_op_end(); I != E; ++I) {
1072     // Check that there's space for the operand.
1073     if (I->get() + I->getSize() > E->get())
1074       return false;
1075 
1076     uint64_t Op = I->getOp();
1077     if ((Op >= dwarf::DW_OP_reg0 && Op <= dwarf::DW_OP_reg31) ||
1078         (Op >= dwarf::DW_OP_breg0 && Op <= dwarf::DW_OP_breg31))
1079       return true;
1080 
1081     // Check that the operand is valid.
1082     switch (Op) {
1083     default:
1084       return false;
1085     case dwarf::DW_OP_LLVM_fragment:
1086       // A fragment operator must appear at the end.
1087       return I->get() + I->getSize() == E->get();
1088     case dwarf::DW_OP_stack_value: {
1089       // Must be the last one or followed by a DW_OP_LLVM_fragment.
1090       if (I->get() + I->getSize() == E->get())
1091         break;
1092       auto J = I;
1093       if ((++J)->getOp() != dwarf::DW_OP_LLVM_fragment)
1094         return false;
1095       break;
1096     }
1097     case dwarf::DW_OP_swap: {
1098       // Must be more than one implicit element on the stack.
1099 
1100       // FIXME: A better way to implement this would be to add a local variable
1101       // that keeps track of the stack depth and introduce something like a
1102       // DW_LLVM_OP_implicit_location as a placeholder for the location this
1103       // DIExpression is attached to, or else pass the number of implicit stack
1104       // elements into isValid.
1105       if (getNumElements() == 1)
1106         return false;
1107       break;
1108     }
1109     case dwarf::DW_OP_LLVM_entry_value: {
1110       // An entry value operator must appear at the beginning and the number of
1111       // operations it cover can currently only be 1, because we support only
1112       // entry values of a simple register location. One reason for this is that
1113       // we currently can't calculate the size of the resulting DWARF block for
1114       // other expressions.
1115       return I->get() == expr_op_begin()->get() && I->getArg(0) == 1;
1116     }
1117     case dwarf::DW_OP_LLVM_implicit_pointer:
1118     case dwarf::DW_OP_LLVM_convert:
1119     case dwarf::DW_OP_LLVM_arg:
1120     case dwarf::DW_OP_LLVM_tag_offset:
1121     case dwarf::DW_OP_constu:
1122     case dwarf::DW_OP_plus_uconst:
1123     case dwarf::DW_OP_plus:
1124     case dwarf::DW_OP_minus:
1125     case dwarf::DW_OP_mul:
1126     case dwarf::DW_OP_div:
1127     case dwarf::DW_OP_mod:
1128     case dwarf::DW_OP_or:
1129     case dwarf::DW_OP_and:
1130     case dwarf::DW_OP_xor:
1131     case dwarf::DW_OP_shl:
1132     case dwarf::DW_OP_shr:
1133     case dwarf::DW_OP_shra:
1134     case dwarf::DW_OP_deref:
1135     case dwarf::DW_OP_deref_size:
1136     case dwarf::DW_OP_xderef:
1137     case dwarf::DW_OP_lit0:
1138     case dwarf::DW_OP_not:
1139     case dwarf::DW_OP_dup:
1140     case dwarf::DW_OP_regx:
1141     case dwarf::DW_OP_bregx:
1142     case dwarf::DW_OP_push_object_address:
1143     case dwarf::DW_OP_over:
1144     case dwarf::DW_OP_consts:
1145       break;
1146     }
1147   }
1148   return true;
1149 }
1150 
1151 bool DIExpression::isImplicit() const {
1152   if (!isValid())
1153     return false;
1154 
1155   if (getNumElements() == 0)
1156     return false;
1157 
1158   for (const auto &It : expr_ops()) {
1159     switch (It.getOp()) {
1160     default:
1161       break;
1162     case dwarf::DW_OP_stack_value:
1163     case dwarf::DW_OP_LLVM_tag_offset:
1164       return true;
1165     }
1166   }
1167 
1168   return false;
1169 }
1170 
1171 bool DIExpression::isComplex() const {
1172   if (!isValid())
1173     return false;
1174 
1175   if (getNumElements() == 0)
1176     return false;
1177 
1178   // If there are any elements other than fragment or tag_offset, then some
1179   // kind of complex computation occurs.
1180   for (const auto &It : expr_ops()) {
1181     switch (It.getOp()) {
1182       case dwarf::DW_OP_LLVM_tag_offset:
1183       case dwarf::DW_OP_LLVM_fragment:
1184         continue;
1185       default: return true;
1186     }
1187   }
1188 
1189   return false;
1190 }
1191 
1192 Optional<DIExpression::FragmentInfo>
1193 DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
1194   for (auto I = Start; I != End; ++I)
1195     if (I->getOp() == dwarf::DW_OP_LLVM_fragment) {
1196       DIExpression::FragmentInfo Info = {I->getArg(1), I->getArg(0)};
1197       return Info;
1198     }
1199   return None;
1200 }
1201 
1202 void DIExpression::appendOffset(SmallVectorImpl<uint64_t> &Ops,
1203                                 int64_t Offset) {
1204   if (Offset > 0) {
1205     Ops.push_back(dwarf::DW_OP_plus_uconst);
1206     Ops.push_back(Offset);
1207   } else if (Offset < 0) {
1208     Ops.push_back(dwarf::DW_OP_constu);
1209     Ops.push_back(-Offset);
1210     Ops.push_back(dwarf::DW_OP_minus);
1211   }
1212 }
1213 
1214 bool DIExpression::extractIfOffset(int64_t &Offset) const {
1215   if (getNumElements() == 0) {
1216     Offset = 0;
1217     return true;
1218   }
1219 
1220   if (getNumElements() == 2 && Elements[0] == dwarf::DW_OP_plus_uconst) {
1221     Offset = Elements[1];
1222     return true;
1223   }
1224 
1225   if (getNumElements() == 3 && Elements[0] == dwarf::DW_OP_constu) {
1226     if (Elements[2] == dwarf::DW_OP_plus) {
1227       Offset = Elements[1];
1228       return true;
1229     }
1230     if (Elements[2] == dwarf::DW_OP_minus) {
1231       Offset = -Elements[1];
1232       return true;
1233     }
1234   }
1235 
1236   return false;
1237 }
1238 
1239 const DIExpression *DIExpression::extractAddressClass(const DIExpression *Expr,
1240                                                       unsigned &AddrClass) {
1241   // FIXME: This seems fragile. Nothing that verifies that these elements
1242   // actually map to ops and not operands.
1243   const unsigned PatternSize = 4;
1244   if (Expr->Elements.size() >= PatternSize &&
1245       Expr->Elements[PatternSize - 4] == dwarf::DW_OP_constu &&
1246       Expr->Elements[PatternSize - 2] == dwarf::DW_OP_swap &&
1247       Expr->Elements[PatternSize - 1] == dwarf::DW_OP_xderef) {
1248     AddrClass = Expr->Elements[PatternSize - 3];
1249 
1250     if (Expr->Elements.size() == PatternSize)
1251       return nullptr;
1252     return DIExpression::get(Expr->getContext(),
1253                              makeArrayRef(&*Expr->Elements.begin(),
1254                                           Expr->Elements.size() - PatternSize));
1255   }
1256   return Expr;
1257 }
1258 
1259 DIExpression *DIExpression::prepend(const DIExpression *Expr, uint8_t Flags,
1260                                     int64_t Offset) {
1261   SmallVector<uint64_t, 8> Ops;
1262   if (Flags & DIExpression::DerefBefore)
1263     Ops.push_back(dwarf::DW_OP_deref);
1264 
1265   appendOffset(Ops, Offset);
1266   if (Flags & DIExpression::DerefAfter)
1267     Ops.push_back(dwarf::DW_OP_deref);
1268 
1269   bool StackValue = Flags & DIExpression::StackValue;
1270   bool EntryValue = Flags & DIExpression::EntryValue;
1271 
1272   return prependOpcodes(Expr, Ops, StackValue, EntryValue);
1273 }
1274 
1275 DIExpression *DIExpression::appendOpsToArg(const DIExpression *Expr,
1276                                            ArrayRef<uint64_t> Ops,
1277                                            unsigned ArgNo, bool StackValue) {
1278   assert(Expr && "Can't add ops to this expression");
1279 
1280   // Handle non-variadic intrinsics by prepending the opcodes.
1281   if (!any_of(Expr->expr_ops(),
1282               [](auto Op) { return Op.getOp() == dwarf::DW_OP_LLVM_arg; })) {
1283     assert(ArgNo == 0 &&
1284            "Location Index must be 0 for a non-variadic expression.");
1285     SmallVector<uint64_t, 8> NewOps(Ops.begin(), Ops.end());
1286     return DIExpression::prependOpcodes(Expr, NewOps, StackValue);
1287   }
1288 
1289   SmallVector<uint64_t, 8> NewOps;
1290   for (auto Op : Expr->expr_ops()) {
1291     Op.appendToVector(NewOps);
1292     if (Op.getOp() == dwarf::DW_OP_LLVM_arg && Op.getArg(0) == ArgNo)
1293       NewOps.insert(NewOps.end(), Ops.begin(), Ops.end());
1294   }
1295 
1296   return DIExpression::get(Expr->getContext(), NewOps);
1297 }
1298 
1299 DIExpression *DIExpression::replaceArg(const DIExpression *Expr,
1300                                        uint64_t OldArg, uint64_t NewArg) {
1301   assert(Expr && "Can't replace args in this expression");
1302 
1303   SmallVector<uint64_t, 8> NewOps;
1304 
1305   for (auto Op : Expr->expr_ops()) {
1306     if (Op.getOp() != dwarf::DW_OP_LLVM_arg || Op.getArg(0) < OldArg) {
1307       Op.appendToVector(NewOps);
1308       continue;
1309     }
1310     NewOps.push_back(dwarf::DW_OP_LLVM_arg);
1311     uint64_t Arg = Op.getArg(0) == OldArg ? NewArg : Op.getArg(0);
1312     // OldArg has been deleted from the Op list, so decrement all indices
1313     // greater than it.
1314     if (Arg > OldArg)
1315       --Arg;
1316     NewOps.push_back(Arg);
1317   }
1318   return DIExpression::get(Expr->getContext(), NewOps);
1319 }
1320 
1321 DIExpression *DIExpression::prependOpcodes(const DIExpression *Expr,
1322                                            SmallVectorImpl<uint64_t> &Ops,
1323                                            bool StackValue,
1324                                            bool EntryValue) {
1325   assert(Expr && "Can't prepend ops to this expression");
1326 
1327   if (EntryValue) {
1328     Ops.push_back(dwarf::DW_OP_LLVM_entry_value);
1329     // Use a block size of 1 for the target register operand.  The
1330     // DWARF backend currently cannot emit entry values with a block
1331     // size > 1.
1332     Ops.push_back(1);
1333   }
1334 
1335   // If there are no ops to prepend, do not even add the DW_OP_stack_value.
1336   if (Ops.empty())
1337     StackValue = false;
1338   for (auto Op : Expr->expr_ops()) {
1339     // A DW_OP_stack_value comes at the end, but before a DW_OP_LLVM_fragment.
1340     if (StackValue) {
1341       if (Op.getOp() == dwarf::DW_OP_stack_value)
1342         StackValue = false;
1343       else if (Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
1344         Ops.push_back(dwarf::DW_OP_stack_value);
1345         StackValue = false;
1346       }
1347     }
1348     Op.appendToVector(Ops);
1349   }
1350   if (StackValue)
1351     Ops.push_back(dwarf::DW_OP_stack_value);
1352   return DIExpression::get(Expr->getContext(), Ops);
1353 }
1354 
1355 DIExpression *DIExpression::append(const DIExpression *Expr,
1356                                    ArrayRef<uint64_t> Ops) {
1357   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
1358 
1359   // Copy Expr's current op list.
1360   SmallVector<uint64_t, 16> NewOps;
1361   for (auto Op : Expr->expr_ops()) {
1362     // Append new opcodes before DW_OP_{stack_value, LLVM_fragment}.
1363     if (Op.getOp() == dwarf::DW_OP_stack_value ||
1364         Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
1365       NewOps.append(Ops.begin(), Ops.end());
1366 
1367       // Ensure that the new opcodes are only appended once.
1368       Ops = None;
1369     }
1370     Op.appendToVector(NewOps);
1371   }
1372 
1373   NewOps.append(Ops.begin(), Ops.end());
1374   auto *result = DIExpression::get(Expr->getContext(), NewOps);
1375   assert(result->isValid() && "concatenated expression is not valid");
1376   return result;
1377 }
1378 
1379 DIExpression *DIExpression::appendToStack(const DIExpression *Expr,
1380                                           ArrayRef<uint64_t> Ops) {
1381   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
1382   assert(none_of(Ops,
1383                  [](uint64_t Op) {
1384                    return Op == dwarf::DW_OP_stack_value ||
1385                           Op == dwarf::DW_OP_LLVM_fragment;
1386                  }) &&
1387          "Can't append this op");
1388 
1389   // Append a DW_OP_deref after Expr's current op list if it's non-empty and
1390   // has no DW_OP_stack_value.
1391   //
1392   // Match .* DW_OP_stack_value (DW_OP_LLVM_fragment A B)?.
1393   Optional<FragmentInfo> FI = Expr->getFragmentInfo();
1394   unsigned DropUntilStackValue = FI.hasValue() ? 3 : 0;
1395   ArrayRef<uint64_t> ExprOpsBeforeFragment =
1396       Expr->getElements().drop_back(DropUntilStackValue);
1397   bool NeedsDeref = (Expr->getNumElements() > DropUntilStackValue) &&
1398                     (ExprOpsBeforeFragment.back() != dwarf::DW_OP_stack_value);
1399   bool NeedsStackValue = NeedsDeref || ExprOpsBeforeFragment.empty();
1400 
1401   // Append a DW_OP_deref after Expr's current op list if needed, then append
1402   // the new ops, and finally ensure that a single DW_OP_stack_value is present.
1403   SmallVector<uint64_t, 16> NewOps;
1404   if (NeedsDeref)
1405     NewOps.push_back(dwarf::DW_OP_deref);
1406   NewOps.append(Ops.begin(), Ops.end());
1407   if (NeedsStackValue)
1408     NewOps.push_back(dwarf::DW_OP_stack_value);
1409   return DIExpression::append(Expr, NewOps);
1410 }
1411 
1412 Optional<DIExpression *> DIExpression::createFragmentExpression(
1413     const DIExpression *Expr, unsigned OffsetInBits, unsigned SizeInBits) {
1414   SmallVector<uint64_t, 8> Ops;
1415   // Copy over the expression, but leave off any trailing DW_OP_LLVM_fragment.
1416   if (Expr) {
1417     for (auto Op : Expr->expr_ops()) {
1418       switch (Op.getOp()) {
1419       default: break;
1420       case dwarf::DW_OP_shr:
1421       case dwarf::DW_OP_shra:
1422       case dwarf::DW_OP_shl:
1423       case dwarf::DW_OP_plus:
1424       case dwarf::DW_OP_plus_uconst:
1425       case dwarf::DW_OP_minus:
1426         // We can't safely split arithmetic or shift operations into multiple
1427         // fragments because we can't express carry-over between fragments.
1428         //
1429         // FIXME: We *could* preserve the lowest fragment of a constant offset
1430         // operation if the offset fits into SizeInBits.
1431         return None;
1432       case dwarf::DW_OP_LLVM_fragment: {
1433         // Make the new offset point into the existing fragment.
1434         uint64_t FragmentOffsetInBits = Op.getArg(0);
1435         uint64_t FragmentSizeInBits = Op.getArg(1);
1436         (void)FragmentSizeInBits;
1437         assert((OffsetInBits + SizeInBits <= FragmentSizeInBits) &&
1438                "new fragment outside of original fragment");
1439         OffsetInBits += FragmentOffsetInBits;
1440         continue;
1441       }
1442       }
1443       Op.appendToVector(Ops);
1444     }
1445   }
1446   assert(Expr && "Unknown DIExpression");
1447   Ops.push_back(dwarf::DW_OP_LLVM_fragment);
1448   Ops.push_back(OffsetInBits);
1449   Ops.push_back(SizeInBits);
1450   return DIExpression::get(Expr->getContext(), Ops);
1451 }
1452 
1453 bool DIExpression::isConstant() const {
1454   // Recognize DW_OP_constu C DW_OP_stack_value (DW_OP_LLVM_fragment Len Ofs)?.
1455   if (getNumElements() != 3 && getNumElements() != 6)
1456     return false;
1457   if (getElement(0) != dwarf::DW_OP_constu ||
1458       getElement(2) != dwarf::DW_OP_stack_value)
1459     return false;
1460   if (getNumElements() == 6 && getElement(3) != dwarf::DW_OP_LLVM_fragment)
1461     return false;
1462   return true;
1463 }
1464 
1465 bool DIExpression::isSignedConstant() const {
1466   // Recognize DW_OP_consts C
1467   if (getNumElements() != 2)
1468     return false;
1469   if (getElement(0) != dwarf::DW_OP_consts)
1470     return false;
1471   return true;
1472 }
1473 
1474 DIExpression::ExtOps DIExpression::getExtOps(unsigned FromSize, unsigned ToSize,
1475                                              bool Signed) {
1476   dwarf::TypeKind TK = Signed ? dwarf::DW_ATE_signed : dwarf::DW_ATE_unsigned;
1477   DIExpression::ExtOps Ops{{dwarf::DW_OP_LLVM_convert, FromSize, TK,
1478                             dwarf::DW_OP_LLVM_convert, ToSize, TK}};
1479   return Ops;
1480 }
1481 
1482 DIExpression *DIExpression::appendExt(const DIExpression *Expr,
1483                                       unsigned FromSize, unsigned ToSize,
1484                                       bool Signed) {
1485   return appendToStack(Expr, getExtOps(FromSize, ToSize, Signed));
1486 }
1487 
1488 DIGlobalVariableExpression *
1489 DIGlobalVariableExpression::getImpl(LLVMContext &Context, Metadata *Variable,
1490                                     Metadata *Expression, StorageType Storage,
1491                                     bool ShouldCreate) {
1492   DEFINE_GETIMPL_LOOKUP(DIGlobalVariableExpression, (Variable, Expression));
1493   Metadata *Ops[] = {Variable, Expression};
1494   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIGlobalVariableExpression, Ops);
1495 }
1496 
1497 DIObjCProperty *DIObjCProperty::getImpl(
1498     LLVMContext &Context, MDString *Name, Metadata *File, unsigned Line,
1499     MDString *GetterName, MDString *SetterName, unsigned Attributes,
1500     Metadata *Type, StorageType Storage, bool ShouldCreate) {
1501   assert(isCanonical(Name) && "Expected canonical MDString");
1502   assert(isCanonical(GetterName) && "Expected canonical MDString");
1503   assert(isCanonical(SetterName) && "Expected canonical MDString");
1504   DEFINE_GETIMPL_LOOKUP(DIObjCProperty, (Name, File, Line, GetterName,
1505                                          SetterName, Attributes, Type));
1506   Metadata *Ops[] = {Name, File, GetterName, SetterName, Type};
1507   DEFINE_GETIMPL_STORE(DIObjCProperty, (Line, Attributes), Ops);
1508 }
1509 
1510 DIImportedEntity *DIImportedEntity::getImpl(LLVMContext &Context, unsigned Tag,
1511                                             Metadata *Scope, Metadata *Entity,
1512                                             Metadata *File, unsigned Line,
1513                                             MDString *Name, StorageType Storage,
1514                                             bool ShouldCreate) {
1515   assert(isCanonical(Name) && "Expected canonical MDString");
1516   DEFINE_GETIMPL_LOOKUP(DIImportedEntity,
1517                         (Tag, Scope, Entity, File, Line, Name));
1518   Metadata *Ops[] = {Scope, Entity, Name, File};
1519   DEFINE_GETIMPL_STORE(DIImportedEntity, (Tag, Line), Ops);
1520 }
1521 
1522 DIMacro *DIMacro::getImpl(LLVMContext &Context, unsigned MIType,
1523                           unsigned Line, MDString *Name, MDString *Value,
1524                           StorageType Storage, bool ShouldCreate) {
1525   assert(isCanonical(Name) && "Expected canonical MDString");
1526   DEFINE_GETIMPL_LOOKUP(DIMacro, (MIType, Line, Name, Value));
1527   Metadata *Ops[] = { Name, Value };
1528   DEFINE_GETIMPL_STORE(DIMacro, (MIType, Line), Ops);
1529 }
1530 
1531 DIMacroFile *DIMacroFile::getImpl(LLVMContext &Context, unsigned MIType,
1532                                   unsigned Line, Metadata *File,
1533                                   Metadata *Elements, StorageType Storage,
1534                                   bool ShouldCreate) {
1535   DEFINE_GETIMPL_LOOKUP(DIMacroFile,
1536                         (MIType, Line, File, Elements));
1537   Metadata *Ops[] = { File, Elements };
1538   DEFINE_GETIMPL_STORE(DIMacroFile, (MIType, Line), Ops);
1539 }
1540 
1541 DIArgList *DIArgList::getImpl(LLVMContext &Context,
1542                               ArrayRef<ValueAsMetadata *> Args,
1543                               StorageType Storage, bool ShouldCreate) {
1544   DEFINE_GETIMPL_LOOKUP(DIArgList, (Args));
1545   DEFINE_GETIMPL_STORE_NO_OPS(DIArgList, (Args));
1546 }
1547 
1548 void DIArgList::handleChangedOperand(void *Ref, Metadata *New) {
1549   ValueAsMetadata **OldVMPtr = static_cast<ValueAsMetadata **>(Ref);
1550   assert((!New || isa<ValueAsMetadata>(New)) &&
1551          "DIArgList must be passed a ValueAsMetadata");
1552   untrack();
1553   ValueAsMetadata *NewVM = cast_or_null<ValueAsMetadata>(New);
1554   for (ValueAsMetadata *&VM : Args) {
1555     if (&VM == OldVMPtr) {
1556       if (NewVM)
1557         VM = NewVM;
1558       else
1559         VM = ValueAsMetadata::get(UndefValue::get(VM->getValue()->getType()));
1560     }
1561   }
1562   track();
1563 }
1564 void DIArgList::track() {
1565   for (ValueAsMetadata *&VAM : Args)
1566     if (VAM)
1567       MetadataTracking::track(&VAM, *VAM, *this);
1568 }
1569 void DIArgList::untrack() {
1570   for (ValueAsMetadata *&VAM : Args)
1571     if (VAM)
1572       MetadataTracking::untrack(&VAM, *VAM);
1573 }
1574 void DIArgList::dropAllReferences() {
1575   untrack();
1576   Args.clear();
1577   MDNode::dropAllReferences();
1578 }
1579