1 //===--- Module.cpp - Describe a module -----------------------------------===//
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 // This file defines the Module class, which describes a module in the source
11 // code.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Basic/Module.h"
16 #include "clang/Basic/FileManager.h"
17 #include "clang/Basic/LangOptions.h"
18 #include "clang/Basic/TargetInfo.h"
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringSwitch.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/raw_ostream.h"
24 
25 using namespace clang;
26 
27 Module::Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent,
28                bool IsFramework, bool IsExplicit, unsigned VisibilityID)
29     : Name(Name), DefinitionLoc(DefinitionLoc), Parent(Parent), Directory(),
30       Umbrella(), Signature(0), ASTFile(nullptr), VisibilityID(VisibilityID),
31       IsMissingRequirement(false), HasIncompatibleModuleFile(false),
32       IsAvailable(true), IsFromModuleFile(false), IsFramework(IsFramework),
33       IsExplicit(IsExplicit), IsSystem(false), IsExternC(false),
34       IsInferred(false), InferSubmodules(false), InferExplicitSubmodules(false),
35       InferExportWildcard(false), ConfigMacrosExhaustive(false),
36       NameVisibility(Hidden) {
37   if (Parent) {
38     if (!Parent->isAvailable())
39       IsAvailable = false;
40     if (Parent->IsSystem)
41       IsSystem = true;
42     if (Parent->IsExternC)
43       IsExternC = true;
44     IsMissingRequirement = Parent->IsMissingRequirement;
45 
46     Parent->SubModuleIndex[Name] = Parent->SubModules.size();
47     Parent->SubModules.push_back(this);
48   }
49 }
50 
51 Module::~Module() {
52   for (submodule_iterator I = submodule_begin(), IEnd = submodule_end();
53        I != IEnd; ++I) {
54     delete *I;
55   }
56 }
57 
58 /// \brief Determine whether a translation unit built using the current
59 /// language options has the given feature.
60 static bool hasFeature(StringRef Feature, const LangOptions &LangOpts,
61                        const TargetInfo &Target) {
62   bool HasFeature = llvm::StringSwitch<bool>(Feature)
63                         .Case("altivec", LangOpts.AltiVec)
64                         .Case("blocks", LangOpts.Blocks)
65                         .Case("cplusplus", LangOpts.CPlusPlus)
66                         .Case("cplusplus11", LangOpts.CPlusPlus11)
67                         .Case("freestanding", LangOpts.Freestanding)
68                         .Case("gnuinlineasm", LangOpts.GNUAsm)
69                         .Case("objc", LangOpts.ObjC1)
70                         .Case("objc_arc", LangOpts.ObjCAutoRefCount)
71                         .Case("opencl", LangOpts.OpenCL)
72                         .Case("tls", Target.isTLSSupported())
73                         .Case("zvector", LangOpts.ZVector)
74                         .Default(Target.hasFeature(Feature));
75   if (!HasFeature)
76     HasFeature = std::find(LangOpts.ModuleFeatures.begin(),
77                            LangOpts.ModuleFeatures.end(),
78                            Feature) != LangOpts.ModuleFeatures.end();
79   return HasFeature;
80 }
81 
82 bool Module::isAvailable(const LangOptions &LangOpts, const TargetInfo &Target,
83                          Requirement &Req,
84                          UnresolvedHeaderDirective &MissingHeader) const {
85   if (IsAvailable)
86     return true;
87 
88   for (const Module *Current = this; Current; Current = Current->Parent) {
89     for (unsigned I = 0, N = Current->Requirements.size(); I != N; ++I) {
90       if (hasFeature(Current->Requirements[I].first, LangOpts, Target) !=
91               Current->Requirements[I].second) {
92         Req = Current->Requirements[I];
93         return false;
94       }
95     }
96     if (!Current->MissingHeaders.empty()) {
97       MissingHeader = Current->MissingHeaders.front();
98       return false;
99     }
100   }
101 
102   llvm_unreachable("could not find a reason why module is unavailable");
103 }
104 
105 bool Module::isSubModuleOf(const Module *Other) const {
106   const Module *This = this;
107   do {
108     if (This == Other)
109       return true;
110 
111     This = This->Parent;
112   } while (This);
113 
114   return false;
115 }
116 
117 const Module *Module::getTopLevelModule() const {
118   const Module *Result = this;
119   while (Result->Parent)
120     Result = Result->Parent;
121 
122   return Result;
123 }
124 
125 std::string Module::getFullModuleName() const {
126   SmallVector<StringRef, 2> Names;
127 
128   // Build up the set of module names (from innermost to outermost).
129   for (const Module *M = this; M; M = M->Parent)
130     Names.push_back(M->Name);
131 
132   std::string Result;
133   for (SmallVectorImpl<StringRef>::reverse_iterator I = Names.rbegin(),
134                                                  IEnd = Names.rend();
135        I != IEnd; ++I) {
136     if (!Result.empty())
137       Result += '.';
138 
139     Result += *I;
140   }
141 
142   return Result;
143 }
144 
145 bool Module::fullModuleNameIs(ArrayRef<StringRef> nameParts) const {
146   for (const Module *M = this; M; M = M->Parent) {
147     if (nameParts.empty() || M->Name != nameParts.back())
148       return false;
149     nameParts = nameParts.drop_back();
150   }
151   return nameParts.empty();
152 }
153 
154 Module::DirectoryName Module::getUmbrellaDir() const {
155   if (Header U = getUmbrellaHeader())
156     return {"", U.Entry->getDir()};
157 
158   return {UmbrellaAsWritten, Umbrella.dyn_cast<const DirectoryEntry *>()};
159 }
160 
161 ArrayRef<const FileEntry *> Module::getTopHeaders(FileManager &FileMgr) {
162   if (!TopHeaderNames.empty()) {
163     for (std::vector<std::string>::iterator
164            I = TopHeaderNames.begin(), E = TopHeaderNames.end(); I != E; ++I) {
165       if (const FileEntry *FE = FileMgr.getFile(*I))
166         TopHeaders.insert(FE);
167     }
168     TopHeaderNames.clear();
169   }
170 
171   return llvm::makeArrayRef(TopHeaders.begin(), TopHeaders.end());
172 }
173 
174 bool Module::directlyUses(const Module *Requested) const {
175   auto *Top = getTopLevelModule();
176 
177   // A top-level module implicitly uses itself.
178   if (Requested->isSubModuleOf(Top))
179     return true;
180 
181   for (auto *Use : Top->DirectUses)
182     if (Requested->isSubModuleOf(Use))
183       return true;
184   return false;
185 }
186 
187 void Module::addRequirement(StringRef Feature, bool RequiredState,
188                             const LangOptions &LangOpts,
189                             const TargetInfo &Target) {
190   Requirements.push_back(Requirement(Feature, RequiredState));
191 
192   // If this feature is currently available, we're done.
193   if (hasFeature(Feature, LangOpts, Target) == RequiredState)
194     return;
195 
196   markUnavailable(/*MissingRequirement*/true);
197 }
198 
199 void Module::markUnavailable(bool MissingRequirement) {
200   auto needUpdate = [MissingRequirement](Module *M) {
201     return M->IsAvailable || (!M->IsMissingRequirement && MissingRequirement);
202   };
203 
204   if (!needUpdate(this))
205     return;
206 
207   SmallVector<Module *, 2> Stack;
208   Stack.push_back(this);
209   while (!Stack.empty()) {
210     Module *Current = Stack.back();
211     Stack.pop_back();
212 
213     if (!needUpdate(Current))
214       continue;
215 
216     Current->IsAvailable = false;
217     Current->IsMissingRequirement |= MissingRequirement;
218     for (submodule_iterator Sub = Current->submodule_begin(),
219                          SubEnd = Current->submodule_end();
220          Sub != SubEnd; ++Sub) {
221       if (needUpdate(*Sub))
222         Stack.push_back(*Sub);
223     }
224   }
225 }
226 
227 Module *Module::findSubmodule(StringRef Name) const {
228   llvm::StringMap<unsigned>::const_iterator Pos = SubModuleIndex.find(Name);
229   if (Pos == SubModuleIndex.end())
230     return nullptr;
231 
232   return SubModules[Pos->getValue()];
233 }
234 
235 static void printModuleId(raw_ostream &OS, const ModuleId &Id) {
236   for (unsigned I = 0, N = Id.size(); I != N; ++I) {
237     if (I)
238       OS << ".";
239     OS << Id[I].first;
240   }
241 }
242 
243 void Module::getExportedModules(SmallVectorImpl<Module *> &Exported) const {
244   // All non-explicit submodules are exported.
245   for (std::vector<Module *>::const_iterator I = SubModules.begin(),
246                                              E = SubModules.end();
247        I != E; ++I) {
248     Module *Mod = *I;
249     if (!Mod->IsExplicit)
250       Exported.push_back(Mod);
251   }
252 
253   // Find re-exported modules by filtering the list of imported modules.
254   bool AnyWildcard = false;
255   bool UnrestrictedWildcard = false;
256   SmallVector<Module *, 4> WildcardRestrictions;
257   for (unsigned I = 0, N = Exports.size(); I != N; ++I) {
258     Module *Mod = Exports[I].getPointer();
259     if (!Exports[I].getInt()) {
260       // Export a named module directly; no wildcards involved.
261       Exported.push_back(Mod);
262 
263       continue;
264     }
265 
266     // Wildcard export: export all of the imported modules that match
267     // the given pattern.
268     AnyWildcard = true;
269     if (UnrestrictedWildcard)
270       continue;
271 
272     if (Module *Restriction = Exports[I].getPointer())
273       WildcardRestrictions.push_back(Restriction);
274     else {
275       WildcardRestrictions.clear();
276       UnrestrictedWildcard = true;
277     }
278   }
279 
280   // If there were any wildcards, push any imported modules that were
281   // re-exported by the wildcard restriction.
282   if (!AnyWildcard)
283     return;
284 
285   for (unsigned I = 0, N = Imports.size(); I != N; ++I) {
286     Module *Mod = Imports[I];
287     bool Acceptable = UnrestrictedWildcard;
288     if (!Acceptable) {
289       // Check whether this module meets one of the restrictions.
290       for (unsigned R = 0, NR = WildcardRestrictions.size(); R != NR; ++R) {
291         Module *Restriction = WildcardRestrictions[R];
292         if (Mod == Restriction || Mod->isSubModuleOf(Restriction)) {
293           Acceptable = true;
294           break;
295         }
296       }
297     }
298 
299     if (!Acceptable)
300       continue;
301 
302     Exported.push_back(Mod);
303   }
304 }
305 
306 void Module::buildVisibleModulesCache() const {
307   assert(VisibleModulesCache.empty() && "cache does not need building");
308 
309   // This module is visible to itself.
310   VisibleModulesCache.insert(this);
311 
312   // Every imported module is visible.
313   SmallVector<Module *, 16> Stack(Imports.begin(), Imports.end());
314   while (!Stack.empty()) {
315     Module *CurrModule = Stack.pop_back_val();
316 
317     // Every module transitively exported by an imported module is visible.
318     if (VisibleModulesCache.insert(CurrModule).second)
319       CurrModule->getExportedModules(Stack);
320   }
321 }
322 
323 void Module::print(raw_ostream &OS, unsigned Indent) const {
324   OS.indent(Indent);
325   if (IsFramework)
326     OS << "framework ";
327   if (IsExplicit)
328     OS << "explicit ";
329   OS << "module " << Name;
330 
331   if (IsSystem || IsExternC) {
332     OS.indent(Indent + 2);
333     if (IsSystem)
334       OS << " [system]";
335     if (IsExternC)
336       OS << " [extern_c]";
337   }
338 
339   OS << " {\n";
340 
341   if (!Requirements.empty()) {
342     OS.indent(Indent + 2);
343     OS << "requires ";
344     for (unsigned I = 0, N = Requirements.size(); I != N; ++I) {
345       if (I)
346         OS << ", ";
347       if (!Requirements[I].second)
348         OS << "!";
349       OS << Requirements[I].first;
350     }
351     OS << "\n";
352   }
353 
354   if (Header H = getUmbrellaHeader()) {
355     OS.indent(Indent + 2);
356     OS << "umbrella header \"";
357     OS.write_escaped(H.NameAsWritten);
358     OS << "\"\n";
359   } else if (DirectoryName D = getUmbrellaDir()) {
360     OS.indent(Indent + 2);
361     OS << "umbrella \"";
362     OS.write_escaped(D.NameAsWritten);
363     OS << "\"\n";
364   }
365 
366   if (!ConfigMacros.empty() || ConfigMacrosExhaustive) {
367     OS.indent(Indent + 2);
368     OS << "config_macros ";
369     if (ConfigMacrosExhaustive)
370       OS << "[exhaustive]";
371     for (unsigned I = 0, N = ConfigMacros.size(); I != N; ++I) {
372       if (I)
373         OS << ", ";
374       OS << ConfigMacros[I];
375     }
376     OS << "\n";
377   }
378 
379   struct {
380     StringRef Prefix;
381     HeaderKind Kind;
382   } Kinds[] = {{"", HK_Normal},
383                {"textual ", HK_Textual},
384                {"private ", HK_Private},
385                {"private textual ", HK_PrivateTextual},
386                {"exclude ", HK_Excluded}};
387 
388   for (auto &K : Kinds) {
389     for (auto &H : Headers[K.Kind]) {
390       OS.indent(Indent + 2);
391       OS << K.Prefix << "header \"";
392       OS.write_escaped(H.NameAsWritten);
393       OS << "\"\n";
394     }
395   }
396 
397   for (submodule_const_iterator MI = submodule_begin(), MIEnd = submodule_end();
398        MI != MIEnd; ++MI)
399     // Print inferred subframework modules so that we don't need to re-infer
400     // them (requires expensive directory iteration + stat calls) when we build
401     // the module. Regular inferred submodules are OK, as we need to look at all
402     // those header files anyway.
403     if (!(*MI)->IsInferred || (*MI)->IsFramework)
404       (*MI)->print(OS, Indent + 2);
405 
406   for (unsigned I = 0, N = Exports.size(); I != N; ++I) {
407     OS.indent(Indent + 2);
408     OS << "export ";
409     if (Module *Restriction = Exports[I].getPointer()) {
410       OS << Restriction->getFullModuleName();
411       if (Exports[I].getInt())
412         OS << ".*";
413     } else {
414       OS << "*";
415     }
416     OS << "\n";
417   }
418 
419   for (unsigned I = 0, N = UnresolvedExports.size(); I != N; ++I) {
420     OS.indent(Indent + 2);
421     OS << "export ";
422     printModuleId(OS, UnresolvedExports[I].Id);
423     if (UnresolvedExports[I].Wildcard)
424       OS << (UnresolvedExports[I].Id.empty() ? "*" : ".*");
425     OS << "\n";
426   }
427 
428   for (unsigned I = 0, N = DirectUses.size(); I != N; ++I) {
429     OS.indent(Indent + 2);
430     OS << "use ";
431     OS << DirectUses[I]->getFullModuleName();
432     OS << "\n";
433   }
434 
435   for (unsigned I = 0, N = UnresolvedDirectUses.size(); I != N; ++I) {
436     OS.indent(Indent + 2);
437     OS << "use ";
438     printModuleId(OS, UnresolvedDirectUses[I]);
439     OS << "\n";
440   }
441 
442   for (unsigned I = 0, N = LinkLibraries.size(); I != N; ++I) {
443     OS.indent(Indent + 2);
444     OS << "link ";
445     if (LinkLibraries[I].IsFramework)
446       OS << "framework ";
447     OS << "\"";
448     OS.write_escaped(LinkLibraries[I].Library);
449     OS << "\"";
450   }
451 
452   for (unsigned I = 0, N = UnresolvedConflicts.size(); I != N; ++I) {
453     OS.indent(Indent + 2);
454     OS << "conflict ";
455     printModuleId(OS, UnresolvedConflicts[I].Id);
456     OS << ", \"";
457     OS.write_escaped(UnresolvedConflicts[I].Message);
458     OS << "\"\n";
459   }
460 
461   for (unsigned I = 0, N = Conflicts.size(); I != N; ++I) {
462     OS.indent(Indent + 2);
463     OS << "conflict ";
464     OS << Conflicts[I].Other->getFullModuleName();
465     OS << ", \"";
466     OS.write_escaped(Conflicts[I].Message);
467     OS << "\"\n";
468   }
469 
470   if (InferSubmodules) {
471     OS.indent(Indent + 2);
472     if (InferExplicitSubmodules)
473       OS << "explicit ";
474     OS << "module * {\n";
475     if (InferExportWildcard) {
476       OS.indent(Indent + 4);
477       OS << "export *\n";
478     }
479     OS.indent(Indent + 2);
480     OS << "}\n";
481   }
482 
483   OS.indent(Indent);
484   OS << "}\n";
485 }
486 
487 LLVM_DUMP_METHOD void Module::dump() const {
488   print(llvm::errs());
489 }
490 
491 void VisibleModuleSet::setVisible(Module *M, SourceLocation Loc,
492                                   VisibleCallback Vis, ConflictCallback Cb) {
493   assert(Loc.isValid() && "setVisible expects a valid import location");
494   if (isVisible(M))
495     return;
496 
497   ++Generation;
498 
499   struct Visiting {
500     Module *M;
501     Visiting *ExportedBy;
502   };
503 
504   std::function<void(Visiting)> VisitModule = [&](Visiting V) {
505     // Modules that aren't available cannot be made visible.
506     if (!V.M->isAvailable())
507       return;
508 
509     // Nothing to do for a module that's already visible.
510     unsigned ID = V.M->getVisibilityID();
511     if (ImportLocs.size() <= ID)
512       ImportLocs.resize(ID + 1);
513     else if (ImportLocs[ID].isValid())
514       return;
515 
516     ImportLocs[ID] = Loc;
517     Vis(M);
518 
519     // Make any exported modules visible.
520     SmallVector<Module *, 16> Exports;
521     V.M->getExportedModules(Exports);
522     for (Module *E : Exports)
523       VisitModule({E, &V});
524 
525     for (auto &C : V.M->Conflicts) {
526       if (isVisible(C.Other)) {
527         llvm::SmallVector<Module*, 8> Path;
528         for (Visiting *I = &V; I; I = I->ExportedBy)
529           Path.push_back(I->M);
530         Cb(Path, C.Other, C.Message);
531       }
532     }
533   };
534   VisitModule({M, nullptr});
535 }
536