- Introduce ASTContext::getObjCImplementation() and ASTContext::setObjCImplementation() which use a DenseMap to associate
  an interface/category with its implementation (if one exists).

- Introduce ObjCInterfaceDecl::get/setImplementation() and ObjCCategoryDecl::get/setImplementation() that use the above methods.

- Add a compiler error for when a category is reimplemented.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76508 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 05627b4..304799c 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -824,6 +824,36 @@
   return count;
 }
 
+/// \brief Get the implementation of ObjCInterfaceDecl,or NULL if none exists.
+ObjCImplementationDecl *ASTContext::getObjCImplementation(ObjCInterfaceDecl *D) {
+  llvm::DenseMap<ObjCContainerDecl*, ObjCImplDecl*>::iterator
+    I = ObjCImpls.find(D);
+  if (I != ObjCImpls.end())
+    return cast<ObjCImplementationDecl>(I->second);
+  return 0;
+}
+/// \brief Get the implementation of ObjCCategoryDecl, or NULL if none exists.
+ObjCCategoryImplDecl *ASTContext::getObjCImplementation(ObjCCategoryDecl *D) {
+  llvm::DenseMap<ObjCContainerDecl*, ObjCImplDecl*>::iterator
+    I = ObjCImpls.find(D);
+  if (I != ObjCImpls.end())
+    return cast<ObjCCategoryImplDecl>(I->second);
+  return 0;
+}
+
+/// \brief Set the implementation of ObjCInterfaceDecl.
+void ASTContext::setObjCImplementation(ObjCInterfaceDecl *IFaceD,
+                           ObjCImplementationDecl *ImplD) {
+  assert(IFaceD && ImplD && "Passed null params");
+  ObjCImpls[IFaceD] = ImplD;
+}
+/// \brief Set the implementation of ObjCCategoryDecl.
+void ASTContext::setObjCImplementation(ObjCCategoryDecl *CatD,
+                           ObjCCategoryImplDecl *ImplD) {
+  assert(CatD && ImplD && "Passed null params");
+  ObjCImpls[CatD] = ImplD;
+}
+
 /// getInterfaceLayoutImpl - Get or compute information about the
 /// layout of the given interface.
 ///