Reapply r69771, with updates & fixes:
Rework the shadow struct that is layed out for Objective-C classes.
- Superclasses are now always laid out in 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
were incorrect (the ASTRecordLayout was correct however, which
meant our debug info didn't coincide with ivar offsets, for
example).
- This is still very suboptimal (for example, ivar are looked up
recursively, 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@69811 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index a993963..e93ea2f 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -47,26 +47,38 @@
///
static const FieldDecl *LookupFieldDeclForIvar(ASTContext &Context,
const ObjCInterfaceDecl *OID,
- const ObjCIvarDecl *OIVD) {
+ const ObjCIvarDecl *OIVD,
+ const ObjCInterfaceDecl *&Found) {
assert(!OID->isForwardDecl() && "Invalid interface decl!");
const RecordDecl *RecordForDecl = Context.addRecordToClass(OID);
assert(RecordForDecl && "lookupFieldDeclForIvar no storage for class");
DeclContext::lookup_const_result Lookup =
RecordForDecl->lookup(Context, OIVD->getDeclName());
- assert((Lookup.first != Lookup.second) && "field decl not found");
- return cast<FieldDecl>(*Lookup.first);
+
+ if (Lookup.first != Lookup.second) {
+ Found = OID;
+ return cast<FieldDecl>(*Lookup.first);
+ }
+
+ // If lookup failed, try the superclass.
+ //
+ // FIXME: This is slow, we shouldn't need to do this.
+ const ObjCInterfaceDecl *Super = OID->getSuperClass();
+ assert(OID && "field decl not found!");
+ return LookupFieldDeclForIvar(Context, Super, OIVD, Found);
}
uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM,
const ObjCInterfaceDecl *OID,
const ObjCIvarDecl *Ivar) {
assert(!OID->isForwardDecl() && "Invalid interface decl!");
- QualType T = CGM.getContext().getObjCInterfaceType(OID);
- const llvm::StructType *STy = GetConcreteClassStruct(CGM, OID);
+ const ObjCInterfaceDecl *Container;
+ const FieldDecl *Field =
+ LookupFieldDeclForIvar(CGM.getContext(), OID, Ivar, Container);
+ QualType T = CGM.getContext().getObjCInterfaceType(Container);
+ const llvm::StructType *STy = GetConcreteClassStruct(CGM, Container);
const llvm::StructLayout *Layout =
CGM.getTargetData().getStructLayout(STy);
- const FieldDecl *Field =
- LookupFieldDeclForIvar(CGM.getContext(), OID, Ivar);
if (!Field->isBitField())
return Layout->getElementOffset(CGM.getTypes().getLLVMFieldNo(Field));
@@ -97,8 +109,9 @@
// purposes, it would be cleaner to use a GEP on the proper type
// since the structure layout is fixed; however for that we need to
// be able to walk the class chain for an Ivar.
+ const ObjCInterfaceDecl *Container;
const FieldDecl *Field =
- LookupFieldDeclForIvar(CGF.CGM.getContext(), OID, Ivar);
+ LookupFieldDeclForIvar(CGF.CGM.getContext(), OID, Ivar, Container);
// (char *) BaseValue
llvm::Type *I8Ptr = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);