Add ModuleDepGraphFactory

This completes the missing piece from swiftlang#34073 and means the frontend may now serialize moduledecl-based dependencies.

Author: CodaFi

lib/AST/FrontendSourceFileDepGraphFactory.cpp

@@ -241,8 +241,10 @@ bool fine_grained_dependencies::withReferenceDependencies(
     const DependencyTracker &depTracker, StringRef outputPath,
     bool alsoEmitDotFile,
     llvm::function_ref<bool(SourceFileDepGraph &&)> cont) {
-  if (MSF.dyn_cast<ModuleDecl *>()) {
-    llvm_unreachable("Cannot construct dependency graph for modules!");
+  if (auto *MD = MSF.dyn_cast<ModuleDecl *>()) {
+    SourceFileDepGraph g =
+        ModuleDepGraphFactory(MD, alsoEmitDotFile).construct();
+    return cont(std::move(g));
   } else {
     auto *SF = MSF.get<SourceFile *>();
     SourceFileDepGraph g = FrontendSourceFileDepGraphFactory(
@@ -632,3 +634,75 @@ FrontendSourceFileDepGraphFactory::getFingerprintIfAny(const Decl *d) {
   }
   return None;
 }
+
+//==============================================================================
+// MARK: ModuleDepGraphFactory
+//==============================================================================
+
+ModuleDepGraphFactory::ModuleDepGraphFactory(ModuleDecl *Mod, bool emitDot)
+    : AbstractSourceFileDepGraphFactory(
+          /*include private*/ true, Mod->getASTContext().hadError(),
+          Mod->getNameStr(), "0xBADBEEF", emitDot, Mod->getASTContext().Diags),
+      Mod(Mod) {}
+
+void ModuleDepGraphFactory::addAllDefinedDecls() {
+  // TODO: express the multiple provides and depends streams with variadic
+  // templates
+
+  // Many kinds of Decls become top-level depends.
+
+  SmallVector<Decl *, 32> TopLevelDecls;
+  Mod->getTopLevelDecls(TopLevelDecls);
+  DeclFinder declFinder(TopLevelDecls, includePrivateDeps,
+                        [this](VisibleDeclConsumer &consumer) {
+                          return Mod->lookupClassMembers({}, consumer);
+                        });
+
+  addAllDefinedDeclsOfAGivenType<NodeKind::topLevel>(
+      declFinder.precedenceGroups);
+  addAllDefinedDeclsOfAGivenType<NodeKind::topLevel>(
+      declFinder.memberOperatorDecls);
+  addAllDefinedDeclsOfAGivenType<NodeKind::topLevel>(declFinder.operators);
+  addAllDefinedDeclsOfAGivenType<NodeKind::topLevel>(declFinder.topNominals);
+  addAllDefinedDeclsOfAGivenType<NodeKind::topLevel>(declFinder.topValues);
+  addAllDefinedDeclsOfAGivenType<NodeKind::nominal>(declFinder.allNominals);
+  addAllDefinedDeclsOfAGivenType<NodeKind::potentialMember>(
+      declFinder.potentialMemberHolders);
+  addAllDefinedDeclsOfAGivenType<NodeKind::member>(
+      declFinder.valuesInExtensions);
+  addAllDefinedDeclsOfAGivenType<NodeKind::dynamicLookup>(
+      declFinder.classMembers);
+}
+
+/// Given an array of Decls or pairs of them in \p declsOrPairs
+/// create node pairs for context and name
+template <NodeKind kind, typename ContentsT>
+void ModuleDepGraphFactory::addAllDefinedDeclsOfAGivenType(
+    std::vector<ContentsT> &contentsVec) {
+  for (const auto &declOrPair : contentsVec) {
+    Optional<std::string> fp = getFingerprintIfAny(declOrPair);
+    addADefinedDecl(
+        DependencyKey::createForProvidedEntityInterface<kind>(declOrPair),
+        fp ? StringRef(fp.getValue()) : Optional<StringRef>());
+  }
+}
+
+//==============================================================================
+// MARK: ModuleDepGraphFactory - adding individual defined Decls
+//==============================================================================
+
+/// At present, only \c NominalTypeDecls have (body) fingerprints
+Optional<std::string> ModuleDepGraphFactory::getFingerprintIfAny(
+    std::pair<const NominalTypeDecl *, const ValueDecl *>) {
+  return None;
+}
+Optional<std::string>
+ModuleDepGraphFactory::getFingerprintIfAny(const Decl *d) {
+  if (const auto *idc = dyn_cast<IterableDeclContext>(d)) {
+    auto result = idc->getBodyFingerprint();
+    assert((!result || !result->empty()) &&
+           "Fingerprint should never be empty");
+    return result;
+  }
+  return None;
+}

lib/AST/FrontendSourceFileDepGraphFactory.h

@@ -54,6 +54,30 @@ class FrontendSourceFileDepGraphFactory
   static Optional<std::string> getFingerprintIfAny(const Decl *d);
 };
 
+class ModuleDepGraphFactory : public AbstractSourceFileDepGraphFactory {
+  ModuleDecl *const Mod;
+
+public:
+  ModuleDepGraphFactory(ModuleDecl *Mod, bool emitDot);
+
+  ~ModuleDepGraphFactory() override = default;
+
+private:
+  void addAllDefinedDecls() override;
+  void addAllUsedDecls() override {}
+
+  /// Given an array of Decls or pairs of them in \p declsOrPairs
+  /// create node pairs for context and name
+  template <NodeKind kind, typename ContentsT>
+  void addAllDefinedDeclsOfAGivenType(std::vector<ContentsT> &contentsVec);
+
+  /// At present, only nominals, protocols, and extensions have (body)
+  /// fingerprints
+  static Optional<std::string> getFingerprintIfAny(
+      std::pair<const NominalTypeDecl *, const ValueDecl *>);
+  static Optional<std::string> getFingerprintIfAny(const Decl *d);
+};
+
 } // namespace fine_grained_dependencies
 } // namespace swift
 

lib/FrontendTool/FrontendTool.cpp

@@ -2292,7 +2292,23 @@ static bool performCompileStepsPostSILGen(CompilerInstance &Instance,
 
     SerializationOptions serializationOpts =
         Invocation.computeSerializationOptions(outs, Instance.getMainModule());
-    serialize(MSF, serializationOpts, SM.get());
+    if (serializationOpts.ExperimentalCrossModuleIncrementalInfo) {
+      const auto alsoEmitDotFile =
+          Instance.getInvocation()
+              .getLangOptions()
+              .EmitFineGrainedDependencySourcefileDotFiles;
+
+      using SourceFileDepGraph = fine_grained_dependencies::SourceFileDepGraph;
+      auto *Mod = MSF.get<ModuleDecl *>();
+      fine_grained_dependencies::withReferenceDependencies(
+          Mod, *Instance.getDependencyTracker(), Mod->getModuleFilename(),
+          alsoEmitDotFile, [](SourceFileDepGraph &&g) {
+            serialize(MSF, serializationOpts, SM.get(), &g);
+            return false;
+          });
+    } else {
+      serialize(MSF, serializationOpts, SM.get());
+    }
   };
 
   // Set the serialization action, so that the SIL module