Make our marking of virtual members functions in a class be

deterministic and work properly with templates. Once a class that
needs a vtable has been defined, we now do one if two things:

  - If the class has no key function, we place the class on a list of
    classes whose virtual functions will need to be "marked" at the
    end of the translation unit. The delay until the end of the
    translation unit is needed because we might see template
    specializations of these virtual functions.
  - If the class has a key function, we do nothing; when the key
    function is defined, the class will be placed on the
    aforementioned list.

At the end of the translation unit, we "mark" all of the virtual
functions of the classes on the list as used, possibly causing
template instantiation and other classes to be added to the
list. This gets LLVM's lib/Support/CommandLine.cpp compiling again.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@92821 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 51 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index ecf95d7eb6..623bf8ae7e 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -2054,7 +2054,7 @@ void Sema::CheckCompletedCXXClass(CXXRecordDecl *Record) {
 
   if (!Record->isDependentType())
     AddImplicitlyDeclaredMembersToClass(Record);
-
+  
   if (Record->isInvalidDecl())
     return;
 
@@ -5693,67 +5693,30 @@ void Sema::MaybeMarkVirtualMembersReferenced(SourceLocation Loc,
   if (!RD->isDynamicClass())
     return;
 
-  if (!MD->isOutOfLine()) {
-    // The only inline functions we care about are constructors. We also defer
-    // marking the virtual members as referenced until we've reached the end
-    // of the translation unit. We do this because we need to know the key
-    // function of the class in order to determine the key function.
-    if (isa<CXXConstructorDecl>(MD))
-      ClassesWithUnmarkedVirtualMembers.insert(std::make_pair(RD, Loc));
+  // Only out-of-line definitions matter.
+  if (!MD->isOutOfLine())
+    return;
+  
+  const CXXMethodDecl *KeyFunction = Context.getKeyFunction(RD);
+  if (!KeyFunction || KeyFunction->getCanonicalDecl() != MD->getCanonicalDecl())
     return;
-  }
-
-  switch (RD->getTemplateSpecializationKind()) {
-  case TSK_Undeclared:
-  case TSK_ExplicitSpecialization: {
-    const CXXMethodDecl *KeyFunction = Context.getKeyFunction(RD);
-
-    if (!KeyFunction) {
-      // This record does not have a key function, so we assume that the vtable
-      // will be emitted when it's used by the constructor.
-      if (!isa<CXXConstructorDecl>(MD))
-        return;
-    } else if (KeyFunction->getCanonicalDecl() != MD->getCanonicalDecl()) {
-      // We don't have the right key function.
-      return;
-    }
-    break;
-  }
-
-  case TSK_ImplicitInstantiation:
-  case TSK_ExplicitInstantiationDeclaration:
-  case TSK_ExplicitInstantiationDefinition:
-    // Always mark the virtual members of an instantiated template.
-    break;
-  }
 
-  // Mark the members as referenced.
-  MarkVirtualMembersReferenced(Loc, RD);
-  ClassesWithUnmarkedVirtualMembers.erase(RD);
+  // We will need to mark all of the virtual members as referenced to build the
+  // vtable.
+  ClassesWithUnmarkedVirtualMembers.push_back(std::make_pair(RD, Loc));
 }
 
 bool Sema::ProcessPendingClassesWithUnmarkedVirtualMembers() {
   if (ClassesWithUnmarkedVirtualMembers.empty())
     return false;
   
-  for (std::map<CXXRecordDecl *, SourceLocation>::iterator i = 
-       ClassesWithUnmarkedVirtualMembers.begin(), 
-       e = ClassesWithUnmarkedVirtualMembers.end(); i != e; ++i) {
-    CXXRecordDecl *RD = i->first;
-    
-    const CXXMethodDecl *KeyFunction = Context.getKeyFunction(RD);
-    if (KeyFunction) {
-      // We know that the class has a key function. If the key function was
-      // declared in this translation unit, then it the class decl would not 
-      // have been in the ClassesWithUnmarkedVirtualMembers map.
-      continue;
-    }
-    
-    SourceLocation Loc = i->second;
+  while (!ClassesWithUnmarkedVirtualMembers.empty()) {
+    CXXRecordDecl *RD = ClassesWithUnmarkedVirtualMembers.back().first;
+    SourceLocation Loc = ClassesWithUnmarkedVirtualMembers.back().second;
+    ClassesWithUnmarkedVirtualMembers.pop_back();
     MarkVirtualMembersReferenced(Loc, RD);
   }
   
-  ClassesWithUnmarkedVirtualMembers.clear();
   return true;
 }