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/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index e0f4492..c62a905 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -4220,62 +4220,29 @@
return GV;
}
-/// countInheritedIvars - count number of ivars in class and its super class(s)
-///
-static int countInheritedIvars(const ObjCInterfaceDecl *OI,
- ASTContext &Context) {
- int count = 0;
- if (!OI)
- return 0;
- const ObjCInterfaceDecl *SuperClass = OI->getSuperClass();
- if (SuperClass)
- count += countInheritedIvars(SuperClass, Context);
- for (ObjCInterfaceDecl::ivar_iterator I = OI->ivar_begin(),
- E = OI->ivar_end(); I != E; ++I)
- ++count;
- // look into properties.
- for (ObjCInterfaceDecl::prop_iterator I = OI->prop_begin(Context),
- E = OI->prop_end(Context); I != E; ++I) {
- if ((*I)->getPropertyIvarDecl())
- ++count;
- }
- return count;
-}
-
void CGObjCNonFragileABIMac::GetClassSizeInfo(const ObjCInterfaceDecl *OID,
uint32_t &InstanceStart,
uint32_t &InstanceSize) {
assert(!OID->isForwardDecl() && "Invalid interface decl!");
const llvm::StructLayout *Layout = GetInterfaceDeclStructLayout(OID);
- int countSuperClassIvars = countInheritedIvars(OID->getSuperClass(),
- CGM.getContext());
const RecordDecl *RD = CGM.getContext().addRecordToClass(OID);
- RecordDecl::field_iterator firstField = RD->field_begin(CGM.getContext());
- RecordDecl::field_iterator lastField = RD->field_end(CGM.getContext());
- while (countSuperClassIvars-- > 0) {
- lastField = firstField;
- ++firstField;
- }
-
- for (RecordDecl::field_iterator e = RD->field_end(CGM.getContext()),
- ifield = firstField; ifield != e; ++ifield)
- lastField = ifield;
-
- InstanceStart = InstanceSize = 0;
- if (lastField != RD->field_end(CGM.getContext())) {
- FieldDecl *Field = *lastField;
- const llvm::Type *FieldTy =
- CGM.getTypes().ConvertTypeForMem(Field->getType());
- unsigned Size = CGM.getTargetData().getTypePaddedSize(FieldTy);
- InstanceSize = GetIvarBaseOffset(Layout, Field) + Size;
- if (firstField == RD->field_end(CGM.getContext()))
- InstanceStart = InstanceSize;
- else {
- Field = *firstField;
- InstanceStart = GetIvarBaseOffset(Layout, Field);
- }
- }
+
+ // Field 0 is always the superclass record (which may be empty).
+ RecordDecl::field_iterator fi = RD->field_begin(CGM.getContext());
+ RecordDecl::field_iterator fe = RD->field_end(CGM.getContext());
+ assert(fi != fe && "class record should never be empty!");
+
+ InstanceStart = CGM.getContext().getTypeSize((*fi)->getType()) / 8;
+
+ // We report the size of the instance as the offset following the
+ // last ivar (which is, of course, not the actual size).
+ std::advance(fi, std::distance(fi, fe) - 1);
+ const FieldDecl *LastField = *fi;
+ uint64_t Offset = GetIvarBaseOffset(Layout, LastField);
+ // Add size of type (rounded to next byte).
+ InstanceSize = (Offset +
+ (CGM.getContext().getTypeSize(LastField->getType()) + 7) / 8);
}
void CGObjCNonFragileABIMac::GenerateClass(const ObjCImplementationDecl *ID) {