Rework the shadow struct that is layed out for Objective-C classes.
- Superclasses are now always laid out their shadow structure at the
first field.
- Prior to this, the entire class heirarchy was flattened into a
single structure which meant that alignment, padding, and bitfields
weren't packed correctly (the ASTRecordLayout was correct however,
which meant our debug info didn't coincide with ivar offsets, for
example).
- This is still very suboptimal, but I believe the ivar layout itself
is now at least close to correct.
- <rdar://problem/6773388> error: objc[29823]: layout bitmap sliding
backwards
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69771 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclObjC.cpp b/lib/AST/DeclObjC.cpp
index 5df5ff3..be23e30 100644
--- a/lib/AST/DeclObjC.cpp
+++ b/lib/AST/DeclObjC.cpp
@@ -380,14 +380,32 @@
///
const FieldDecl *
ObjCInterfaceDecl::lookupFieldDeclForIvar(ASTContext &Context,
- const ObjCIvarDecl *IVar) const {
+ const ObjCIvarDecl *OIVD) const {
assert(!isForwardDecl() && "Invalid interface decl!");
const RecordDecl *RecordForDecl = Context.addRecordToClass(this);
- assert(RecordForDecl && "lookupFieldDeclForIvar no storage for class");
DeclContext::lookup_const_result Lookup =
- RecordForDecl->lookup(Context, IVar->getDeclName());
- assert((Lookup.first != Lookup.second) && "field decl not found");
- return cast<FieldDecl>(*Lookup.first);
+ RecordForDecl->lookup(Context, OIVD->getDeclName());
+
+ if (Lookup.first != Lookup.second)
+ return cast<FieldDecl>(*Lookup.first);
+
+ // If lookup failed, try the superclass.
+ //
+ // FIXME: This is very non-performant. However, the root problem
+ // here is not the lookup itself. The main issue is that we should
+ // be able to map from an IvarDecl back to the context it lives
+ // inside; then this problem goes away. Currently, however,
+ // IvarDecl's live inside the translation unit!!!!
+ //
+ // Fixing IvarDecl's is less obvious than it might appear, we need
+ // to choose where synthesized ivars should live, and we also need
+ // to decide where to put IvarDecl's which appeared in an
+ // implementation context (either in the situation where they must
+ // duplicate the instance variables, or if there was no instance
+ // declaration).
+ const ObjCInterfaceDecl *OID = getSuperClass();
+ assert(OID && "field decl not found!");
+ return OID->lookupFieldDeclForIvar(Context, OIVD);
}
//===----------------------------------------------------------------------===//