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