[modules] When creating a declaration, cache its owning module immediately

rather than waiting until it's queried.

Currently this is only applied to local submodule visibility mode, as we don't
yet allocate storage for the owning module in non-local-visibility modules
compilations.


This reinstates r302965, reverted in r303037, with a fix for the reported
crash, which occurred when reparenting a local declaration to be a child of
a hidden imported declaration (specifically during template instantiation).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@303224 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 19 insertions, 62 deletions

diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index ca1d27e950..e7b0914641 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -93,11 +93,10 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
       ValueWithBytesObjCTypeMethod(nullptr), NSArrayDecl(nullptr),
       ArrayWithObjectsMethod(nullptr), NSDictionaryDecl(nullptr),
       DictionaryWithObjectsMethod(nullptr), GlobalNewDeleteDeclared(false),
-      TUKind(TUKind), NumSFINAEErrors(0), CachedFakeTopLevelModule(nullptr),
-      AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
-      NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
-      CurrentInstantiationScope(nullptr), DisableTypoCorrection(false),
-      TyposCorrected(0), AnalysisWarnings(*this),
+      TUKind(TUKind), NumSFINAEErrors(0), AccessCheckingSFINAE(false),
+      InNonInstantiationSFINAEContext(false), NonInstantiationEntries(0),
+      ArgumentPackSubstitutionIndex(-1), CurrentInstantiationScope(nullptr),
+      DisableTypoCorrection(false), TyposCorrected(0), AnalysisWarnings(*this),
       ThreadSafetyDeclCache(nullptr), VarDataSharingAttributesStack(nullptr),
       CurScope(nullptr), Ident_super(nullptr), Ident___float128(nullptr) {
   TUScope = nullptr;
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 2e069a9def..dca51b0e8c 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -16047,6 +16047,14 @@ void Sema::ActOnModuleBegin(SourceLocation DirectiveLoc, Module *Mod) {
     ModuleScopes.back().OuterVisibleModules = std::move(VisibleModules);
 
   VisibleModules.setVisible(Mod, DirectiveLoc);
+
+  // The enclosing context is now part of this module.
+  // FIXME: Consider creating a child DeclContext to hold the entities
+  // lexically within the module.
+  if (getLangOpts().trackLocalOwningModule()) {
+    cast<Decl>(CurContext)->setHidden(true);
+    cast<Decl>(CurContext)->setLocalOwningModule(Mod);
+  }
 }
 
 void Sema::ActOnModuleEnd(SourceLocation EomLoc, Module *Mod) {
@@ -16075,6 +16083,13 @@ void Sema::ActOnModuleEnd(SourceLocation EomLoc, Module *Mod) {
     DirectiveLoc = EomLoc;
   }
   BuildModuleInclude(DirectiveLoc, Mod);
+
+  // Any further declarations are in whatever module we returned to.
+  if (getLangOpts().trackLocalOwningModule()) {
+    cast<Decl>(CurContext)->setLocalOwningModule(getCurrentModule());
+    if (!getCurrentModule())
+      cast<Decl>(CurContext)->setHidden(false);
+  }
 }
 
 void Sema::createImplicitModuleImportForErrorRecovery(SourceLocation Loc,
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index c5b579a4b2..04350831c6 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -1326,62 +1326,6 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
   return !R.empty();
 }
 
-Module *Sema::getOwningModule(Decl *Entity) {
-  // If it's imported, grab its owning module.
-  Module *M = Entity->getImportedOwningModule();
-  if (M || !isa<NamedDecl>(Entity) || !cast<NamedDecl>(Entity)->isHidden())
-    return M;
-  assert(!Entity->isFromASTFile() &&
-         "hidden entity from AST file has no owning module");
-
-  if (!getLangOpts().ModulesLocalVisibility) {
-    // If we're not tracking visibility locally, the only way a declaration
-    // can be hidden and local is if it's hidden because it's parent is (for
-    // instance, maybe this is a lazily-declared special member of an imported
-    // class).
-    auto *Parent = cast<NamedDecl>(Entity->getDeclContext());
-    assert(Parent->isHidden() && "unexpectedly hidden decl");
-    return getOwningModule(Parent);
-  }
-
-  // It's local and hidden; grab or compute its owning module.
-  M = Entity->getLocalOwningModule();
-  if (M)
-    return M;
-
-  if (auto *Containing =
-          PP.getModuleContainingLocation(Entity->getLocation())) {
-    M = Containing;
-  } else if (Entity->isInvalidDecl() || Entity->getLocation().isInvalid()) {
-    // Don't bother tracking visibility for invalid declarations with broken
-    // locations.
-    cast<NamedDecl>(Entity)->setHidden(false);
-  } else {
-    // We need to assign a module to an entity that exists outside of any
-    // module, so that we can hide it from modules that we textually enter.
-    // Invent a fake module for all such entities.
-    if (!CachedFakeTopLevelModule) {
-      CachedFakeTopLevelModule =
-          PP.getHeaderSearchInfo().getModuleMap().findOrCreateModule(
-              "<top-level>", nullptr, false, false).first;
-
-      auto &SrcMgr = PP.getSourceManager();
-      SourceLocation StartLoc =
-          SrcMgr.getLocForStartOfFile(SrcMgr.getMainFileID());
-      auto &TopLevel = ModuleScopes.empty()
-                           ? VisibleModules
-                           : ModuleScopes[0].OuterVisibleModules;
-      TopLevel.setVisible(CachedFakeTopLevelModule, StartLoc);
-    }
-
-    M = CachedFakeTopLevelModule;
-  }
-
-  if (M)
-    Entity->setLocalOwningModule(M);
-  return M;
-}
-
 void Sema::makeMergedDefinitionVisible(NamedDecl *ND) {
   if (auto *M = getCurrentModule())
     Context.mergeDefinitionIntoModule(ND, M);
@@ -1520,7 +1464,6 @@ bool LookupResult::isVisibleSlow(Sema &SemaRef, NamedDecl *D) {
   if (SemaRef.getLangOpts().ModulesLocalVisibility) {
     DeclModule = SemaRef.getOwningModule(D);
     if (!DeclModule) {
-      // getOwningModule() may have decided the declaration should not be hidden.
       assert(!D->isHidden() && "hidden decl not from a module");
       return true;
     }