AST: Some const goodness for ModuleDecl

Author: slavapestov

include/swift/AST/Module.h

@@ -537,10 +537,10 @@ class ModuleDecl : public DeclContext, public TypeDecl {
   /// \return True if the traversal ran to completion, false if it ended early
   ///         due to the callback.
   bool forAllVisibleModules(AccessPathTy topLevelAccessPath,
-                            llvm::function_ref<bool(ImportedModule)> fn);
+                            llvm::function_ref<bool(ImportedModule)> fn) const;
 
   bool forAllVisibleModules(AccessPathTy topLevelAccessPath,
-                            llvm::function_ref<void(ImportedModule)> fn) {
+                            llvm::function_ref<void(ImportedModule)> fn) const {
     return forAllVisibleModules(topLevelAccessPath,
                                 [=](const ImportedModule &import) -> bool {
       fn(import);
@@ -550,7 +550,7 @@ class ModuleDecl : public DeclContext, public TypeDecl {
 
   template <typename Fn>
   bool forAllVisibleModules(AccessPathTy topLevelAccessPath,
-                            Fn &&fn) {
+                            Fn &&fn) const {
     using RetTy = typename std::result_of<Fn(ImportedModule)>::type;
     llvm::function_ref<RetTy(ImportedModule)> wrapped{std::forward<Fn>(fn)};
     return forAllVisibleModules(topLevelAccessPath, wrapped);
@@ -562,7 +562,7 @@ class ModuleDecl : public DeclContext, public TypeDecl {
 
   /// Generate the list of libraries needed to link this module, based on its
   /// imports.
-  void collectLinkLibraries(LinkLibraryCallback callback);
+  void collectLinkLibraries(LinkLibraryCallback callback) const;
 
   /// Returns true if the two access paths contain the same chain of
   /// identifiers.
@@ -826,18 +826,20 @@ class FileUnit : public DeclContext {
   /// \return True if the traversal ran to completion, false if it ended early
   ///         due to the callback.
   bool
-  forAllVisibleModules(llvm::function_ref<bool(ModuleDecl::ImportedModule)> fn);
+  forAllVisibleModules(
+      llvm::function_ref<bool(ModuleDecl::ImportedModule)> fn) const;
 
   bool
-  forAllVisibleModules(llvm::function_ref<void(ModuleDecl::ImportedModule)> fn) {
+  forAllVisibleModules(
+      llvm::function_ref<void(ModuleDecl::ImportedModule)> fn) const {
     return forAllVisibleModules([=](ModuleDecl::ImportedModule import) -> bool {
       fn(import);
       return true;
     });
   }
 
   template <typename Fn>
-  bool forAllVisibleModules(Fn &&fn) {
+  bool forAllVisibleModules(Fn &&fn) const {
     using RetTy = typename std::result_of<Fn(ModuleDecl::ImportedModule)>::type;
     llvm::function_ref<RetTy(ModuleDecl::ImportedModule)> wrapped{
       std::forward<Fn>(fn)

lib/AST/Module.cpp

@@ -1375,7 +1375,8 @@ bool ModuleDecl::registerEntryPointFile(FileUnit *file, SourceLoc diagLoc,
 
 template<bool respectVisibility>
 static bool
-forAllImportedModules(ModuleDecl *topLevel, ModuleDecl::AccessPathTy thisPath,
+forAllImportedModules(const ModuleDecl *topLevel,
+                      ModuleDecl::AccessPathTy thisPath,
                       llvm::function_ref<bool(ModuleDecl::ImportedModule)> fn) {
   using ImportedModule = ModuleDecl::ImportedModule;
   using AccessPathTy = ModuleDecl::AccessPathTy;
@@ -1396,7 +1397,7 @@ forAllImportedModules(ModuleDecl *topLevel, ModuleDecl::AccessPathTy thisPath,
   AccessPathTy overridingPath;
   if (respectVisibility)
     overridingPath = thisPath;
-  stack.push_back(ImportedModule(overridingPath, topLevel));
+  stack.emplace_back(overridingPath, const_cast<ModuleDecl *>(topLevel));
 
   while (!stack.empty()) {
     auto next = stack.pop_back_val();
@@ -1430,12 +1431,12 @@ forAllImportedModules(ModuleDecl *topLevel, ModuleDecl::AccessPathTy thisPath,
 
 bool
 ModuleDecl::forAllVisibleModules(AccessPathTy thisPath,
-                                 llvm::function_ref<bool(ImportedModule)> fn) {
+                                 llvm::function_ref<bool(ImportedModule)> fn) const {
   return forAllImportedModules<true>(this, thisPath, fn);
 }
 
 bool FileUnit::forAllVisibleModules(
-    llvm::function_ref<bool(ModuleDecl::ImportedModule)> fn) {
+    llvm::function_ref<bool(ModuleDecl::ImportedModule)> fn) const {
   if (!getParentModule()->forAllVisibleModules(ModuleDecl::AccessPathTy(), fn))
     return false;
 
@@ -1454,7 +1455,7 @@ bool FileUnit::forAllVisibleModules(
   return true;
 }
 
-void ModuleDecl::collectLinkLibraries(LinkLibraryCallback callback) {
+void ModuleDecl::collectLinkLibraries(LinkLibraryCallback callback) const {
   // FIXME: The proper way to do this depends on the decls used.
   FORWARD(collectLinkLibraries, (callback));
 }