In Objective-C, pull arbitrary attributes from overridden

methods, including indirectly overridden methods like those
declared in protocols and categories.  There are mismatches
that we would like to diagnose but aren't yet, but this   
is fine for now.

I looked at approaches that avoided doing this lookup 
unless we needed it, but the infer-related-result-type
checks were doing it anyway, so I left it with the same
fast-path check for no previous declartions of that 
selector.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135743 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 159 insertions, 158 deletions

diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index d754cffcc5..7beabcc57d 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -155,100 +155,6 @@ bool Sema::CheckObjCMethodOverride(ObjCMethodDecl *NewMethod,
   return false;
 }
 
-/// \brief Check for consistency between a given method declaration and the
-/// methods it overrides within the class hierarchy.
-///
-/// This method walks the inheritance hierarchy starting at the given 
-/// declaration context (\p DC), invoking Sema::CheckObjCMethodOverride() with
-/// the given new method (\p NewMethod) and any method it directly overrides
-/// in the hierarchy. Sema::CheckObjCMethodOverride() is responsible for
-/// checking consistency, e.g., among return types for methods that return a 
-/// related result type.
-static bool CheckObjCMethodOverrides(Sema &S, ObjCMethodDecl *NewMethod,
-                                     DeclContext *DC, 
-                                     bool SkipCurrent = true) {
-  if (!DC)
-    return false;
-  
-  if (!SkipCurrent) {
-    // Look for this method. If we find it, we're done.
-    Selector Sel = NewMethod->getSelector();
-    bool IsInstance = NewMethod->isInstanceMethod();
-    DeclContext::lookup_const_iterator Meth, MethEnd;
-    for (llvm::tie(Meth, MethEnd) = DC->lookup(Sel); Meth != MethEnd; ++Meth) {
-      ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(*Meth);
-      if (MD && MD->isInstanceMethod() == IsInstance)
-        return S.CheckObjCMethodOverride(NewMethod, MD, false);
-    }
-  }
-  
-  if (ObjCInterfaceDecl *Class = llvm::dyn_cast<ObjCInterfaceDecl>(DC)) {
-    // Look through categories.
-    for (ObjCCategoryDecl *Category = Class->getCategoryList();
-         Category; Category = Category->getNextClassCategory()) {
-      if (CheckObjCMethodOverrides(S, NewMethod, Category, false))
-        return true;
-    }
-
-    // Look through protocols.
-    for (ObjCList<ObjCProtocolDecl>::iterator I = Class->protocol_begin(),
-                                           IEnd = Class->protocol_end();
-         I != IEnd; ++I)
-      if (CheckObjCMethodOverrides(S, NewMethod, *I, false))
-        return true;
-    
-    // Look in our superclass.
-    return CheckObjCMethodOverrides(S, NewMethod, Class->getSuperClass(), 
-                                    false);
-  }
-  
-  if (ObjCCategoryDecl *Category = dyn_cast<ObjCCategoryDecl>(DC)) {
-    // Look through protocols.
-    for (ObjCList<ObjCProtocolDecl>::iterator I = Category->protocol_begin(),
-                                           IEnd = Category->protocol_end();
-         I != IEnd; ++I)
-      if (CheckObjCMethodOverrides(S, NewMethod, *I, false))
-        return true;
-    
-    return false;
-  }
-  
-  if (ObjCProtocolDecl *Protocol = dyn_cast<ObjCProtocolDecl>(DC)) {
-    // Look through protocols.
-    for (ObjCList<ObjCProtocolDecl>::iterator I = Protocol->protocol_begin(),
-                                           IEnd = Protocol->protocol_end();
-         I != IEnd; ++I)
-      if (CheckObjCMethodOverrides(S, NewMethod, *I, false))
-        return true;
-    
-    return false;
-  }
-  
-  return false;
-}
-
-bool Sema::CheckObjCMethodOverrides(ObjCMethodDecl *NewMethod, 
-                                    DeclContext *DC) {
-  if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(DC))
-    return ::CheckObjCMethodOverrides(*this, NewMethod, Class);
-
-  if (ObjCCategoryDecl *Category = dyn_cast<ObjCCategoryDecl>(DC))
-    return ::CheckObjCMethodOverrides(*this, NewMethod, Category);
-
-  if (ObjCProtocolDecl *Protocol = dyn_cast<ObjCProtocolDecl>(DC))
-    return ::CheckObjCMethodOverrides(*this, NewMethod, Protocol);
-
-  if (ObjCImplementationDecl *Impl = dyn_cast<ObjCImplementationDecl>(DC))
-    return ::CheckObjCMethodOverrides(*this, NewMethod, 
-                                      Impl->getClassInterface());
-  
-  if (ObjCCategoryImplDecl *CatImpl = dyn_cast<ObjCCategoryImplDecl>(DC))
-    return ::CheckObjCMethodOverrides(*this, NewMethod, 
-                                      CatImpl->getClassInterface());
-  
-  return ::CheckObjCMethodOverrides(*this, NewMethod, CurContext);
-}
-
 /// \brief Check a method declaration for compatibility with the Objective-C
 /// ARC conventions.
 static bool CheckARCMethodDecl(Sema &S, ObjCMethodDecl *method) {
@@ -261,6 +167,7 @@ static bool CheckARCMethodDecl(Sema &S, ObjCMethodDecl *method) {
   case OMF_autorelease:
   case OMF_retainCount:
   case OMF_self:
+  case OMF_performSelector:
     return false;
 
   case OMF_init:
@@ -286,11 +193,6 @@ static bool CheckARCMethodDecl(Sema &S, ObjCMethodDecl *method) {
         method->hasAttr<NSReturnsAutoreleasedAttr>())
       return false;
     break;
-    
-  case OMF_performSelector:
-    // we don't annotate performSelector's
-    return true;
-      
   }
 
   method->addAttr(new (S.Context) NSReturnsRetainedAttr(SourceLocation(),
@@ -855,8 +757,10 @@ Decl *Sema::ActOnStartCategoryImplementation(
     ObjCCategoryImplDecl::Create(Context, CurContext, AtCatImplLoc, CatName,
                                  IDecl);
   /// Check that class of this category is already completely declared.
-  if (!IDecl || IDecl->isForwardDecl())
+  if (!IDecl || IDecl->isForwardDecl()) {
     Diag(ClassLoc, diag::err_undef_interface) << ClassName;
+    CDecl->setInvalidDecl();
+  }
 
   // FIXME: PushOnScopeChains?
   CurContext->addDecl(CDecl);
@@ -2246,25 +2150,140 @@ CheckRelatedResultTypeCompatibility(Sema &S, ObjCMethodDecl *Method,
   return true;
 }
 
-/// \brief Determine if any method in the global method pool has an inferred 
-/// result type.
-static bool 
-anyMethodInfersRelatedResultType(Sema &S, Selector Sel, bool IsInstance) {
-  Sema::GlobalMethodPool::iterator Pos = S.MethodPool.find(Sel);
-  if (Pos == S.MethodPool.end()) {
-    if (S.ExternalSource)
-      Pos = S.ReadMethodPool(Sel);
-    else
-      return 0;
+namespace {
+/// A helper class for searching for methods which a particular method
+/// overrides.
+class OverrideSearch {
+  Sema &S;
+  ObjCMethodDecl *Method;
+  llvm::SmallPtrSet<ObjCContainerDecl*, 8> Searched;
+  llvm::SmallPtrSet<ObjCMethodDecl*, 8> Overridden;
+  bool Recursive;
+
+public:
+  OverrideSearch(Sema &S, ObjCMethodDecl *method) : S(S), Method(method) {
+    Selector selector = method->getSelector();
+
+    // Bypass this search if we've never seen an instance/class method
+    // with this selector before.
+    Sema::GlobalMethodPool::iterator it = S.MethodPool.find(selector);
+    if (it == S.MethodPool.end()) {
+      if (!S.ExternalSource) return;
+      it = S.ReadMethodPool(selector);
+    }
+    ObjCMethodList &list =
+      method->isInstanceMethod() ? it->second.first : it->second.second;
+    if (!list.Method) return;
+
+    ObjCContainerDecl *container
+      = cast<ObjCContainerDecl>(method->getDeclContext());
+
+    // Prevent the search from reaching this container again.  This is
+    // important with categories, which override methods from the
+    // interface and each other.
+    Searched.insert(container);
+    searchFromContainer(container);
   }
-  
-  ObjCMethodList &List = IsInstance ? Pos->second.first : Pos->second.second;
-  for (ObjCMethodList *M = &List; M; M = M->Next) {
-    if (M->Method && M->Method->hasRelatedResultType())
-      return true;
-  }  
-  
-  return false;
+
+  typedef llvm::SmallPtrSet<ObjCMethodDecl*,8>::iterator iterator;
+  iterator begin() const { return Overridden.begin(); }
+  iterator end() const { return Overridden.end(); }
+
+private:
+  void searchFromContainer(ObjCContainerDecl *container) {
+    if (container->isInvalidDecl()) return;
+
+    switch (container->getDeclKind()) {
+#define OBJCCONTAINER(type, base) \
+    case Decl::type: \
+      searchFrom(cast<type##Decl>(container)); \
+      break;
+#define ABSTRACT_DECL(expansion)
+#define DECL(type, base) \
+    case Decl::type:
+#include "clang/AST/DeclNodes.inc"
+      llvm_unreachable("not an ObjC container!");
+    }
+  }
+
+  void searchFrom(ObjCProtocolDecl *protocol) {
+    // A method in a protocol declaration overrides declarations from
+    // referenced ("parent") protocols.
+    search(protocol->getReferencedProtocols());
+  }
+
+  void searchFrom(ObjCCategoryDecl *category) {
+    // A method in a category declaration overrides declarations from
+    // the main class and from protocols the category references.
+    search(category->getClassInterface());
+    search(category->getReferencedProtocols());
+  }
+
+  void searchFrom(ObjCCategoryImplDecl *impl) {
+    // A method in a category definition that has a category
+    // declaration overrides declarations from the category
+    // declaration.
+    if (ObjCCategoryDecl *category = impl->getCategoryDecl()) {
+      search(category);
+
+    // Otherwise it overrides declarations from the class.
+    } else {
+      search(impl->getClassInterface());
+    }
+  }
+
+  void searchFrom(ObjCInterfaceDecl *iface) {
+    // A method in a class declaration overrides declarations from
+
+    //   - categories,
+    for (ObjCCategoryDecl *category = iface->getCategoryList();
+           category; category = category->getNextClassCategory())
+      search(category);
+
+    //   - the super class, and
+    if (ObjCInterfaceDecl *super = iface->getSuperClass())
+      search(super);
+
+    //   - any referenced protocols.
+    search(iface->getReferencedProtocols());
+  }
+
+  void searchFrom(ObjCImplementationDecl *impl) {
+    // A method in a class implementation overrides declarations from
+    // the class interface.
+    search(impl->getClassInterface());
+  }
+
+
+  void search(const ObjCProtocolList &protocols) {
+    for (ObjCProtocolList::iterator i = protocols.begin(), e = protocols.end();
+         i != e; ++i)
+      search(*i);
+  }
+
+  void search(ObjCContainerDecl *container) {
+    // Abort if we've already searched this container.
+    if (!Searched.insert(container)) return;
+
+    // Check for a method in this container which matches this selector.
+    ObjCMethodDecl *meth = container->getMethod(Method->getSelector(),
+                                                Method->isInstanceMethod());
+
+    // If we find one, record it and bail out.
+    if (meth) {
+      Overridden.insert(meth);
+      return;
+    }
+
+    // Otherwise, search for methods that a hypothetical method here
+    // would have overridden.
+
+    // Note that we're now in a recursive case.
+    Recursive = true;
+
+    searchFromContainer(container);
+  }
+};
 }
 
 Decl *Sema::ActOnMethodDeclaration(
@@ -2390,16 +2409,13 @@ Decl *Sema::ActOnMethodDeclaration(
                               Sel.getNumArgs());
   ObjCMethod->setObjCDeclQualifier(
     CvtQTToAstBitMask(ReturnQT.getObjCDeclQualifier()));
-  const ObjCMethodDecl *PrevMethod = 0;
 
   if (AttrList)
     ProcessDeclAttributeList(TUScope, ObjCMethod, AttrList);
 
-  const ObjCMethodDecl *InterfaceMD = 0;
-
   // Add the method now.
-  if (ObjCImplementationDecl *ImpDecl =
-        dyn_cast<ObjCImplementationDecl>(ClassDecl)) {
+  const ObjCMethodDecl *PrevMethod = 0;
+  if (ObjCImplDecl *ImpDecl = dyn_cast<ObjCImplDecl>(ClassDecl)) {
     if (MethodType == tok::minus) {
       PrevMethod = ImpDecl->getInstanceMethod(Sel);
       ImpDecl->addInstanceMethod(ObjCMethod);
@@ -2407,24 +2423,6 @@ Decl *Sema::ActOnMethodDeclaration(
       PrevMethod = ImpDecl->getClassMethod(Sel);
       ImpDecl->addClassMethod(ObjCMethod);
     }
-    InterfaceMD = ImpDecl->getClassInterface()->getMethod(Sel,
-                                                   MethodType == tok::minus);
-    
-    if (ObjCMethod->hasAttrs() &&
-        containsInvalidMethodImplAttribute(ObjCMethod->getAttrs()))
-      Diag(EndLoc, diag::warn_attribute_method_def);
-  } else if (ObjCCategoryImplDecl *CatImpDecl =
-             dyn_cast<ObjCCategoryImplDecl>(ClassDecl)) {
-    if (MethodType == tok::minus) {
-      PrevMethod = CatImpDecl->getInstanceMethod(Sel);
-      CatImpDecl->addInstanceMethod(ObjCMethod);
-    } else {
-      PrevMethod = CatImpDecl->getClassMethod(Sel);
-      CatImpDecl->addClassMethod(ObjCMethod);
-    }
-
-    if (ObjCCategoryDecl *Cat = CatImpDecl->getCategoryDecl())
-      InterfaceMD = Cat->getMethod(Sel, MethodType == tok::minus);
 
     if (ObjCMethod->hasAttrs() &&
         containsInvalidMethodImplAttribute(ObjCMethod->getAttrs()))
@@ -2432,6 +2430,7 @@ Decl *Sema::ActOnMethodDeclaration(
   } else {
     cast<DeclContext>(ClassDecl)->addDecl(ObjCMethod);
   }
+
   if (PrevMethod) {
     // You can never have two method definitions with the same name.
     Diag(ObjCMethod->getLocation(), diag::err_duplicate_method_decl)
@@ -2452,23 +2451,31 @@ Decl *Sema::ActOnMethodDeclaration(
                                    = dyn_cast<ObjCCategoryImplDecl>(ClassDecl))
       CurrentClass = CatImpl->getClassInterface();
   }
-  
-  // Merge information down from the interface declaration if we have one.
-  if (InterfaceMD) {
-    // Inherit the related result type, if we can.
-    if (InterfaceMD->hasRelatedResultType() &&
-        !CheckRelatedResultTypeCompatibility(*this, ObjCMethod, CurrentClass))
+
+  bool isRelatedResultTypeCompatible =
+    (getLangOptions().ObjCInferRelatedResultType &&
+     !CheckRelatedResultTypeCompatibility(*this, ObjCMethod, CurrentClass));
+
+  // Search for overridden methods and merge information down from them.
+  OverrideSearch overrides(*this, ObjCMethod);
+  for (OverrideSearch::iterator
+         i = overrides.begin(), e = overrides.end(); i != e; ++i) {
+    ObjCMethodDecl *overridden = *i;
+
+    // Propagate down the 'related result type' bit from overridden methods.
+    if (isRelatedResultTypeCompatible && overridden->hasRelatedResultType())
       ObjCMethod->SetRelatedResultType();
-      
-    mergeObjCMethodDecls(ObjCMethod, InterfaceMD);
+
+    // Then merge the declarations.
+    mergeObjCMethodDecls(ObjCMethod, overridden);
   }
   
   bool ARCError = false;
   if (getLangOptions().ObjCAutoRefCount)
     ARCError = CheckARCMethodDecl(*this, ObjCMethod);
 
-  if (!ObjCMethod->hasRelatedResultType() && !ARCError &&
-      getLangOptions().ObjCInferRelatedResultType) {
+  if (!ARCError && isRelatedResultTypeCompatible &&
+      !ObjCMethod->hasRelatedResultType()) {
     bool InferRelatedResultType = false;
     switch (ObjCMethod->getMethodFamily()) {
     case OMF_None:
@@ -2493,14 +2500,8 @@ Decl *Sema::ActOnMethodDeclaration(
       break;
     }
     
-    if (InferRelatedResultType &&
-        !CheckRelatedResultTypeCompatibility(*this, ObjCMethod, CurrentClass))
+    if (InferRelatedResultType)
       ObjCMethod->SetRelatedResultType();
-    
-    if (!InterfaceMD && 
-        anyMethodInfersRelatedResultType(*this, ObjCMethod->getSelector(),
-                                         ObjCMethod->isInstanceMethod()))
-      CheckObjCMethodOverrides(ObjCMethod, cast<DeclContext>(ClassDecl));
   }
     
   return ObjCMethod;