xref: /llvm-project/llvm/tools/llvm-readtapi/DiffEngine.cpp (revision 5656d7971b395b6303661e2ef7c3e6960c715b2a) 
1 //===-- DiffEngine.cpp - Structural file comparison -----------------------===//
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 defines the implementation of the llvm-tapi difference
10 // engine, which structurally compares two tbd files.
11 //
12 //===----------------------------------------------------------------------===/
13 #include "DiffEngine.h"
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/Support/Casting.h"
16 #include "llvm/Support/raw_ostream.h"
17 #include "llvm/TextAPI/InterfaceFile.h"
18 #include "llvm/TextAPI/Symbol.h"
19 #include "llvm/TextAPI/Target.h"
20 #include <iterator>
21 
22 using namespace llvm;
23 using namespace MachO;
24 using namespace object;
25 
26 StringRef setOrderIndicator(InterfaceInputOrder Order) {
27   return ((Order == lhs) ? "< " : "> ");
28 }
29 
30 // The following template specialization implementations
31 // need to be explicitly placed into the llvm namespace
32 // to work around a GCC 4.8 bug.
33 namespace llvm {
34 
35 template <typename T, DiffAttrKind U>
36 inline void DiffScalarVal<T, U>::print(raw_ostream &OS, std::string Indent) {
37   OS << Indent << "\t" << setOrderIndicator(Order) << Val << "\n";
38 }
39 
40 template <>
41 inline void
42 DiffScalarVal<StringRef, AD_Diff_Scalar_Str>::print(raw_ostream &OS,
43                                                     std::string Indent) {
44   OS << Indent << "\t\t" << setOrderIndicator(Order) << Val << "\n";
45 }
46 
47 template <>
48 inline void
49 DiffScalarVal<uint8_t, AD_Diff_Scalar_Unsigned>::print(raw_ostream &OS,
50                                                        std::string Indent) {
51   OS << Indent << "\t" << setOrderIndicator(Order) << std::to_string(Val)
52      << "\n";
53 }
54 
55 template <>
56 inline void
57 DiffScalarVal<bool, AD_Diff_Scalar_Bool>::print(raw_ostream &OS,
58                                                 std::string Indent) {
59   OS << Indent << "\t" << setOrderIndicator(Order)
60      << ((Val == true) ? "true" : "false") << "\n";
61 }
62 
63 } // end namespace llvm
64 
65 StringLiteral SymScalar::getSymbolNamePrefix(MachO::SymbolKind Kind) {
66   switch (Kind) {
67   case MachO::SymbolKind::GlobalSymbol:
68     return StringLiteral("");
69   case MachO::SymbolKind::ObjectiveCClass:
70     return ObjC2MetaClassNamePrefix;
71   case MachO::SymbolKind ::ObjectiveCClassEHType:
72     return ObjC2EHTypePrefix;
73   case MachO::SymbolKind ::ObjectiveCInstanceVariable:
74     return ObjC2IVarPrefix;
75   }
76   llvm_unreachable("Unknown llvm::MachO::SymbolKind enum");
77 }
78 
79 std::string SymScalar::getFlagString(const MachO::Symbol *Sym) {
80   if (Sym->getFlags() == SymbolFlags::None)
81     return {};
82   SmallString<64> Flags(" - ");
83   if (Sym->isThreadLocalValue())
84     Flags.append("Thread-Local ");
85   if (Sym->isWeakDefined())
86     Flags.append("Weak-Defined ");
87   if (Sym->isWeakReferenced())
88     Flags.append("Weak-Referenced ");
89   if (Sym->isUndefined())
90     Flags.append("Undefined ");
91   if (Sym->isReexported())
92     Flags.append("Reexported ");
93   if (Sym->isData())
94     Flags.append("Data ");
95   if (Sym->isText())
96     Flags.append("Text ");
97 
98   return std::string(Flags);
99 }
100 
101 void SymScalar::print(raw_ostream &OS, std::string Indent, MachO::Target Targ) {
102   if (Val->getKind() == MachO::SymbolKind::ObjectiveCClass) {
103     if (Targ.Arch == MachO::AK_i386 && Targ.Platform == MachO::PLATFORM_MACOS) {
104       OS << Indent << "\t\t" << ((Order == lhs) ? "< " : "> ")
105          << ObjC1ClassNamePrefix << Val->getName() << getFlagString(Val)
106          << "\n";
107       return;
108     }
109     OS << Indent << "\t\t" << ((Order == lhs) ? "< " : "> ")
110        << ObjC2ClassNamePrefix << Val->getName() << getFlagString(Val) << "\n";
111   }
112   OS << Indent << "\t\t" << ((Order == lhs) ? "< " : "> ")
113      << getSymbolNamePrefix(Val->getKind()) << Val->getName()
114      << getFlagString(Val) << "\n";
115 }
116 
117 bool checkSymbolEquality(llvm::MachO::InterfaceFile::const_symbol_range LHS,
118                          llvm::MachO::InterfaceFile::const_symbol_range RHS) {
119   if (std::distance(LHS.begin(), LHS.end()) !=
120       std::distance(RHS.begin(), RHS.end()))
121     return false;
122   return std::equal(LHS.begin(), LHS.end(), RHS.begin(),
123                     [&](auto LHS, auto RHS) { return *LHS == *RHS; });
124 }
125 
126 template <typename TargetVecT, typename ValTypeT, typename V>
127 void addDiffForTargSlice(V Val, Target Targ, DiffOutput &Diff,
128                          InterfaceInputOrder Order) {
129   auto TargetVector = llvm::find_if(
130       Diff.Values, [&](const std::unique_ptr<AttributeDiff> &RawTVec) {
131         if (TargetVecT *TVec = dyn_cast<TargetVecT>(RawTVec.get()))
132           return TVec->Targ == Targ;
133         return false;
134       });
135   if (TargetVector != Diff.Values.end()) {
136     ValTypeT NewVal(Order, Val);
137     cast<TargetVecT>(TargetVector->get())->TargValues.push_back(NewVal);
138   } else {
139     auto NewTargetVec = std::make_unique<TargetVecT>(Targ);
140     ValTypeT NewVal(Order, Val);
141     NewTargetVec->TargValues.push_back(NewVal);
142     Diff.Values.push_back(std::move(NewTargetVec));
143   }
144 }
145 
146 DiffOutput getSingleAttrDiff(const std::vector<InterfaceFileRef> &IRefVec,
147                              std::string Name, InterfaceInputOrder Order) {
148   DiffOutput Diff(Name);
149   Diff.Kind = AD_Str_Vec;
150   for (const auto &IRef : IRefVec)
151     for (auto Targ : IRef.targets())
152       addDiffForTargSlice<DiffStrVec,
153                           DiffScalarVal<StringRef, AD_Diff_Scalar_Str>>(
154           IRef.getInstallName(), Targ, Diff, Order);
155   return Diff;
156 }
157 
158 DiffOutput
159 getSingleAttrDiff(const std::vector<std::pair<Target, std::string>> &PairVec,
160                   std::string Name, InterfaceInputOrder Order) {
161   DiffOutput Diff(Name);
162   Diff.Kind = AD_Str_Vec;
163   for (const auto &Pair : PairVec)
164     addDiffForTargSlice<DiffStrVec,
165                         DiffScalarVal<StringRef, AD_Diff_Scalar_Str>>(
166         StringRef(Pair.second), Pair.first, Diff, Order);
167   return Diff;
168 }
169 
170 DiffOutput getSingleAttrDiff(InterfaceFile::const_symbol_range SymRange,
171                              std::string Name, InterfaceInputOrder Order) {
172   DiffOutput Diff(Name);
173   Diff.Kind = AD_Sym_Vec;
174   for (const auto *Sym : SymRange)
175     for (auto Targ : Sym->targets())
176       addDiffForTargSlice<DiffSymVec, SymScalar>(Sym, Targ, Diff, Order);
177   return Diff;
178 }
179 
180 template <typename T>
181 DiffOutput getSingleAttrDiff(T SingleAttr, std::string Attribute) {
182   DiffOutput Diff(Attribute);
183   Diff.Kind = SingleAttr.getKind();
184   Diff.Values.push_back(std::make_unique<T>(SingleAttr));
185   return Diff;
186 }
187 
188 template <typename T, DiffAttrKind U>
189 void diffAttribute(std::string Name, std::vector<DiffOutput> &Output,
190                    DiffScalarVal<T, U> Attr) {
191   Output.push_back(getSingleAttrDiff(Attr, Name));
192 }
193 
194 template <typename T>
195 void diffAttribute(std::string Name, std::vector<DiffOutput> &Output,
196                    const T &Val, InterfaceInputOrder Order) {
197   Output.push_back(getSingleAttrDiff(Val, Name, Order));
198 }
199 
200 std::vector<DiffOutput> getSingleIF(InterfaceFile *Interface,
201                                     InterfaceInputOrder Order) {
202   std::vector<DiffOutput> Output;
203   diffAttribute("Install Name", Output,
204                 DiffScalarVal<StringRef, AD_Diff_Scalar_Str>(
205                     Order, Interface->getInstallName()));
206   diffAttribute("Current Version", Output,
207                 DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>(
208                     Order, Interface->getCurrentVersion()));
209   diffAttribute("Compatibility Version", Output,
210                 DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>(
211                     Order, Interface->getCompatibilityVersion()));
212   diffAttribute("Swift ABI Version", Output,
213                 DiffScalarVal<uint8_t, AD_Diff_Scalar_Unsigned>(
214                     Order, Interface->getSwiftABIVersion()));
215   diffAttribute("Two Level Namespace", Output,
216                 DiffScalarVal<bool, AD_Diff_Scalar_Bool>(
217                     Order, Interface->isTwoLevelNamespace()));
218   diffAttribute("Application Extension Safe", Output,
219                 DiffScalarVal<bool, AD_Diff_Scalar_Bool>(
220                     Order, Interface->isApplicationExtensionSafe()));
221   diffAttribute("Reexported Libraries", Output,
222                 Interface->reexportedLibraries(), Order);
223   diffAttribute("Allowable Clients", Output, Interface->allowableClients(),
224                 Order);
225   diffAttribute("Parent Umbrellas", Output, Interface->umbrellas(), Order);
226   diffAttribute("Symbols", Output, Interface->symbols(), Order);
227   for (auto Doc : Interface->documents()) {
228     DiffOutput Documents("Inlined Reexported Frameworks/Libraries");
229     Documents.Kind = AD_Inline_Doc;
230     Documents.Values.push_back(std::make_unique<InlineDoc>(
231         InlineDoc(Doc->getInstallName(), getSingleIF(Doc.get(), Order))));
232     Output.push_back(std::move(Documents));
233   }
234   return Output;
235 }
236 
237 void findAndAddDiff(const std::vector<InterfaceFileRef> &CollectedIRefVec,
238                     const std::vector<InterfaceFileRef> &LookupIRefVec,
239                     DiffOutput &Result, InterfaceInputOrder Order) {
240   Result.Kind = AD_Str_Vec;
241   for (const auto &IRef : CollectedIRefVec)
242     for (auto Targ : IRef.targets()) {
243       auto FoundIRef = llvm::any_of(LookupIRefVec, [&](const auto LIRef) {
244         return llvm::is_contained(LIRef.targets(), Targ) &&
245                IRef.getInstallName() == LIRef.getInstallName();
246       });
247       if (!FoundIRef)
248         addDiffForTargSlice<DiffStrVec,
249                             DiffScalarVal<StringRef, AD_Diff_Scalar_Str>>(
250             IRef.getInstallName(), Targ, Result, Order);
251     }
252 }
253 
254 void findAndAddDiff(
255     const std::vector<std::pair<Target, std::string>> &CollectedPairs,
256     const std::vector<std::pair<Target, std::string>> &LookupPairs,
257     DiffOutput &Result, InterfaceInputOrder Order) {
258   Result.Kind = AD_Str_Vec;
259   for (const auto &Pair : CollectedPairs) {
260     auto FoundPair = llvm::find(LookupPairs, Pair);
261     if (FoundPair == LookupPairs.end())
262       addDiffForTargSlice<DiffStrVec,
263                           DiffScalarVal<StringRef, AD_Diff_Scalar_Str>>(
264           StringRef(Pair.second), Pair.first, Result, Order);
265   }
266 }
267 
268 void findAndAddDiff(InterfaceFile::const_symbol_range CollectedSyms,
269                     InterfaceFile::const_symbol_range LookupSyms,
270                     DiffOutput &Result, InterfaceInputOrder Order) {
271   Result.Kind = AD_Sym_Vec;
272   for (const auto *Sym : CollectedSyms)
273     for (const auto Targ : Sym->targets()) {
274       auto FoundSym = llvm::any_of(LookupSyms, [&](const auto LSym) {
275         return (Sym->getName() == LSym->getName() &&
276                 Sym->getKind() == LSym->getKind() &&
277                 Sym->getFlags() == LSym->getFlags() &&
278                 llvm::is_contained(LSym->targets(), Targ));
279       });
280       if (!FoundSym)
281         addDiffForTargSlice<DiffSymVec, SymScalar>(Sym, Targ, Result, Order);
282     }
283 }
284 
285 template <typename T>
286 DiffOutput recordDifferences(T LHS, T RHS, std::string Attr) {
287   DiffOutput Diff(Attr);
288   if (LHS.getKind() == RHS.getKind()) {
289     Diff.Kind = LHS.getKind();
290     Diff.Values.push_back(std::make_unique<T>(LHS));
291     Diff.Values.push_back(std::make_unique<T>(RHS));
292   }
293   return Diff;
294 }
295 
296 template <typename T>
297 DiffOutput recordDifferences(const std::vector<T> &LHS,
298                              const std::vector<T> &RHS, std::string Attr) {
299   DiffOutput Diff(Attr);
300   Diff.Kind = AD_Str_Vec;
301   findAndAddDiff(LHS, RHS, Diff, lhs);
302   findAndAddDiff(RHS, LHS, Diff, rhs);
303   return Diff;
304 }
305 
306 DiffOutput recordDifferences(llvm::MachO::InterfaceFile::const_symbol_range LHS,
307                              llvm::MachO::InterfaceFile::const_symbol_range RHS,
308                              std::string Attr) {
309   DiffOutput Diff(Attr);
310   Diff.Kind = AD_Sym_Vec;
311   findAndAddDiff(LHS, RHS, Diff, lhs);
312   findAndAddDiff(RHS, LHS, Diff, rhs);
313   return Diff;
314 }
315 
316 std::vector<DiffOutput>
317 DiffEngine::findDifferences(const InterfaceFile *IFLHS,
318                             const InterfaceFile *IFRHS) {
319   std::vector<DiffOutput> Output;
320   if (IFLHS->getInstallName() != IFRHS->getInstallName())
321     Output.push_back(recordDifferences(
322         DiffScalarVal<StringRef, AD_Diff_Scalar_Str>(lhs,
323                                                      IFLHS->getInstallName()),
324         DiffScalarVal<StringRef, AD_Diff_Scalar_Str>(rhs,
325                                                      IFRHS->getInstallName()),
326         "Install Name"));
327 
328   if (IFLHS->getCurrentVersion() != IFRHS->getCurrentVersion())
329     Output.push_back(recordDifferences(
330         DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>(
331             lhs, IFLHS->getCurrentVersion()),
332         DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>(
333             rhs, IFRHS->getCurrentVersion()),
334         "Current Version"));
335   if (IFLHS->getCompatibilityVersion() != IFRHS->getCompatibilityVersion())
336     Output.push_back(recordDifferences(
337         DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>(
338             lhs, IFLHS->getCompatibilityVersion()),
339         DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>(
340             rhs, IFRHS->getCompatibilityVersion()),
341         "Compatibility Version"));
342   if (IFLHS->getSwiftABIVersion() != IFRHS->getSwiftABIVersion())
343     Output.push_back(
344         recordDifferences(DiffScalarVal<uint8_t, AD_Diff_Scalar_Unsigned>(
345                               lhs, IFLHS->getSwiftABIVersion()),
346                           DiffScalarVal<uint8_t, AD_Diff_Scalar_Unsigned>(
347                               rhs, IFRHS->getSwiftABIVersion()),
348                           "Swift ABI Version"));
349 
350   if (IFLHS->isTwoLevelNamespace() != IFRHS->isTwoLevelNamespace())
351     Output.push_back(recordDifferences(DiffScalarVal<bool, AD_Diff_Scalar_Bool>(
352                                            lhs, IFLHS->isTwoLevelNamespace()),
353                                        DiffScalarVal<bool, AD_Diff_Scalar_Bool>(
354                                            rhs, IFRHS->isTwoLevelNamespace()),
355                                        "Two Level Namespace"));
356 
357   if (IFLHS->isApplicationExtensionSafe() !=
358       IFRHS->isApplicationExtensionSafe())
359     Output.push_back(
360         recordDifferences(DiffScalarVal<bool, AD_Diff_Scalar_Bool>(
361                               lhs, IFLHS->isApplicationExtensionSafe()),
362                           DiffScalarVal<bool, AD_Diff_Scalar_Bool>(
363                               rhs, IFRHS->isApplicationExtensionSafe()),
364                           "Application Extension Safe"));
365 
366   if (IFLHS->reexportedLibraries() != IFRHS->reexportedLibraries())
367     Output.push_back(recordDifferences(IFLHS->reexportedLibraries(),
368                                        IFRHS->reexportedLibraries(),
369                                        "Reexported Libraries"));
370 
371   if (IFLHS->allowableClients() != IFRHS->allowableClients())
372     Output.push_back(recordDifferences(IFLHS->allowableClients(),
373                                        IFRHS->allowableClients(),
374                                        "Allowable Clients"));
375 
376   if (IFLHS->umbrellas() != IFRHS->umbrellas())
377     Output.push_back(recordDifferences(IFLHS->umbrellas(), IFRHS->umbrellas(),
378                                        "Parent Umbrellas"));
379 
380   if (!checkSymbolEquality(IFLHS->symbols(), IFRHS->symbols()))
381     Output.push_back(
382         recordDifferences(IFLHS->symbols(), IFRHS->symbols(), "Symbols"));
383 
384   if (IFLHS->documents() != IFRHS->documents()) {
385     DiffOutput Docs("Inlined Reexported Frameworks/Libraries");
386     Docs.Kind = AD_Inline_Doc;
387     std::vector<StringRef> DocsInserted;
388     // Iterate through inline frameworks/libraries from interface file and find
389     // match based on install name.
390     for (auto DocLHS : IFLHS->documents()) {
391       auto Pair = llvm::find_if(IFRHS->documents(), [&](const auto &DocRHS) {
392         return (DocLHS->getInstallName() == DocRHS->getInstallName());
393       });
394       // If a match found, recursively get differences between the pair.
395       if (Pair != IFRHS->documents().end()) {
396         InlineDoc PairDiff =
397             InlineDoc(DocLHS->getInstallName(),
398                       findDifferences(DocLHS.get(), Pair->get()));
399         if (!PairDiff.DocValues.empty())
400           Docs.Values.push_back(
401               std::make_unique<InlineDoc>(std::move(PairDiff)));
402       }
403       // If a match is not found, get attributes from single item.
404       else
405         Docs.Values.push_back(std::make_unique<InlineDoc>(InlineDoc(
406             DocLHS->getInstallName(), getSingleIF(DocLHS.get(), lhs))));
407       DocsInserted.push_back(DocLHS->getInstallName());
408     }
409     for (auto DocRHS : IFRHS->documents()) {
410       auto WasGathered =
411           llvm::any_of(DocsInserted, [&](const auto &GatheredDoc) {
412             return (GatheredDoc == DocRHS->getInstallName());
413           });
414       if (!WasGathered)
415         Docs.Values.push_back(std::make_unique<InlineDoc>(InlineDoc(
416             DocRHS->getInstallName(), getSingleIF(DocRHS.get(), rhs))));
417     }
418     if (!Docs.Values.empty())
419       Output.push_back(std::move(Docs));
420   }
421   return Output;
422 }
423 
424 template <typename T>
425 void printSingleVal(std::string Indent, const DiffOutput &Attr,
426                     raw_ostream &OS) {
427   if (Attr.Values.empty())
428     return;
429   OS << Indent << Attr.Name << "\n";
430   for (auto &RawItem : Attr.Values)
431     if (T *Item = dyn_cast<T>(RawItem.get()))
432       Item->print(OS, Indent);
433 }
434 
435 template <typename T>
436 T *castValues(const std::unique_ptr<AttributeDiff> &RawAttr) {
437   T *CastAttr = cast<T>(RawAttr.get());
438   return CastAttr;
439 }
440 
441 template <typename T> void sortTargetValues(std::vector<T> &TargValues) {
442   llvm::stable_sort(TargValues, [](const auto &ValA, const auto &ValB) {
443     return ValA.getOrder() < ValB.getOrder();
444   });
445   llvm::stable_sort(TargValues, [](const auto &ValA, const auto &ValB) {
446     return ValA.getOrder() == ValB.getOrder() && ValA.getVal() < ValB.getVal();
447   });
448 }
449 
450 template <typename T>
451 void printVecVal(std::string Indent, const DiffOutput &Attr, raw_ostream &OS) {
452   if (Attr.Values.empty())
453     return;
454 
455   OS << Indent << Attr.Name << "\n";
456 
457   std::vector<T *> SortedAttrs;
458 
459   llvm::transform(Attr.Values, std::back_inserter(SortedAttrs), castValues<T>);
460 
461   llvm::sort(SortedAttrs, [&](const auto &ValA, const auto &ValB) {
462     return ValA->Targ < ValB->Targ;
463   });
464 
465   for (auto *Vec : SortedAttrs) {
466     sortTargetValues<DiffScalarVal<StringRef, AD_Diff_Scalar_Str>>(
467         Vec->TargValues);
468     OS << Indent << "\t" << getTargetTripleName(Vec->Targ) << "\n";
469     for (auto &Item : Vec->TargValues)
470       Item.print(OS, Indent);
471   }
472 }
473 
474 template <>
475 void printVecVal<DiffSymVec>(std::string Indent, const DiffOutput &Attr,
476                              raw_ostream &OS) {
477   if (Attr.Values.empty())
478     return;
479 
480   OS << Indent << Attr.Name << "\n";
481 
482   std::vector<DiffSymVec *> SortedAttrs;
483 
484   llvm::transform(Attr.Values, std::back_inserter(SortedAttrs),
485                   castValues<DiffSymVec>);
486 
487   llvm::sort(SortedAttrs, [&](const auto &ValA, const auto &ValB) {
488     return ValA->Targ < ValB->Targ;
489   });
490   for (auto *SymVec : SortedAttrs) {
491     sortTargetValues<SymScalar>(SymVec->TargValues);
492     OS << Indent << "\t" << getTargetTripleName(SymVec->Targ) << "\n";
493     for (auto &Item : SymVec->TargValues)
494       Item.print(OS, Indent, SymVec->Targ);
495   }
496 }
497 
498 void DiffEngine::printDifferences(raw_ostream &OS,
499                                   const std::vector<DiffOutput> &Diffs,
500                                   int IndentCounter) {
501   std::string Indent = std::string(IndentCounter, '\t');
502   for (auto &Attr : Diffs) {
503     switch (Attr.Kind) {
504     case AD_Diff_Scalar_Str:
505       if (IndentCounter == 0)
506         printSingleVal<DiffScalarVal<StringRef, AD_Diff_Scalar_Str>>(Indent,
507                                                                      Attr, OS);
508       break;
509     case AD_Diff_Scalar_PackedVersion:
510       printSingleVal<
511           DiffScalarVal<PackedVersion, AD_Diff_Scalar_PackedVersion>>(Indent,
512                                                                       Attr, OS);
513       break;
514     case AD_Diff_Scalar_Unsigned:
515       printSingleVal<DiffScalarVal<uint8_t, AD_Diff_Scalar_Unsigned>>(Indent,
516                                                                       Attr, OS);
517       break;
518     case AD_Diff_Scalar_Bool:
519       printSingleVal<DiffScalarVal<bool, AD_Diff_Scalar_Bool>>(Indent, Attr,
520                                                                OS);
521       break;
522     case AD_Str_Vec:
523       printVecVal<DiffStrVec>(Indent, Attr, OS);
524       break;
525     case AD_Sym_Vec:
526       printVecVal<DiffSymVec>(Indent, Attr, OS);
527       break;
528     case AD_Inline_Doc:
529       if (!Attr.Values.empty()) {
530         OS << Indent << Attr.Name << "\n";
531         for (auto &Item : Attr.Values)
532           if (InlineDoc *Doc = dyn_cast<InlineDoc>(Item.get()))
533             if (!Doc->DocValues.empty()) {
534               OS << Indent << "\t" << Doc->InstallName << "\n";
535               printDifferences(OS, std::move(Doc->DocValues), 2);
536             }
537       }
538       break;
539     }
540   }
541 }
542 
543 bool DiffEngine::compareFiles(raw_ostream &OS) {
544   const auto *IFLHS = &(FileLHS->getInterfaceFile());
545   const auto *IFRHS = &(FileRHS->getInterfaceFile());
546   if (*IFLHS == *IFRHS)
547     return false;
548   OS << "< " << std::string(IFLHS->getPath().data()) << "\n> "
549      << std::string(IFRHS->getPath().data()) << "\n\n";
550   std::vector<DiffOutput> Diffs = findDifferences(IFLHS, IFRHS);
551   printDifferences(OS, Diffs, 0);
552   return true;
553 }
554