--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/compsupp/symaehabi/symbian_rtti.cpp Mon Oct 19 15:55:17 2009 +0100
@@ -0,0 +1,159 @@
+// Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of the License "ARM EABI LICENCE.txt"
+// which accompanies this distribution, and is available
+// in kernel/eka/compsupp.
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// e32/compsupp/symaehabi/symbian_rtti.cpp
+//
+//
+
+#include "cxxabi.h"
+#include "unwind_env.h"
+#include "unwinder.h"
+#include "symbian_support.h"
+
+// For information about these classes, se
+// www.codesourcery.com/public/cxx-abi/abi.html#rtti.
+using abi::__class_type_info;
+using abi::__si_class_type_info;
+using abi::__vmi_class_type_info;
+using abi::__base_class_type_info;
+
+
+// Given base class info (aBaseInfo) and a derived object pointer (aDerivedObj),
+// this function implements "cast to base" and stores result in aBaseObj. This
+// essentially sets aBaseObj to point to a memory location that represents
+// aDerivedObj as the given base class. This function requires that aBaseInfo
+// describes a base class of the aDerivedObj's class.
+static void _CastUp(const __base_class_type_info& aBaseInfo, TAny** aDerivedObj, TAny** aBaseObj)
+ {
+ // Guard against a null pointer for aDerivedObj
+ if ( ! (*aDerivedObj) )
+ {
+ *aBaseObj = NULL;
+ return;
+ }
+
+ TInt offset = aBaseInfo.__offset_flags >> aBaseInfo.__offset_shift;
+
+ if (aBaseInfo.__offset_flags & aBaseInfo.__virtual_mask)
+ {
+ // For virtual bases, look up offset in vtable + offset.
+
+ // Get vtbl pointer as the first 4 bytes of **aDerivedObj
+ TUint32* vptr = (TUint32*) ( *( (TUint32*) (*aDerivedObj) ) );
+
+ offset = *( vptr + offset / sizeof(TUint32) );
+ }
+
+ // Apply the offset.
+ *aBaseObj = (TAny*) ( ( (TUint8*) *aDerivedObj ) + offset );
+ }
+
+
+// For a description of this function, see comments in unwind_env.h.
+extern "C" TBool _DoDerivedToBaseConversion(const std::type_info* aDerivedType,
+ const std::type_info* aBaseType,
+ TAny** aDerivedObj,
+ TAny** aBaseObj)
+ {
+
+ const std::type_info& type_base_type = typeid(*aBaseType);
+ const std::type_info& type_derived_type = typeid(*aDerivedType);
+
+ // We must proceed depending on the type of the type_info objects for derived
+ // class.
+ if ( type_derived_type == typeid(__si_class_type_info) )
+ {
+ // The __si_class_type_info means that the derived type has a single,
+ // public, non-virtual base, and that the base is at offset zero. We should
+ // be able to simply compare the base type from __si_class_type_info with
+ // aBaseType
+
+ const __si_class_type_info* derived = (const __si_class_type_info*) aDerivedType;
+
+ if ( *(derived->__base_type) == *aBaseType )
+ {
+ // The types match, work done.
+ *aBaseObj = *aDerivedObj;
+ return true;
+ }
+ else
+ {
+ // The types don't match. We should proceed to comparison with the any
+ // classes. In this case there is a single base as follows:
+ const __class_type_info* bType = derived->__base_type;
+
+ // No pointer adjustment required for __si_class_type_info.
+ return _DoDerivedToBaseConversion(bType, aBaseType, aDerivedObj, aBaseObj);
+ }
+ }
+ else if ( type_derived_type == typeid(__vmi_class_type_info) )
+ {
+ // The __vmi_class_type_info is for all other scenarios. We get an array of
+ // bases which we need to traverse and do comparison on.
+
+ const __vmi_class_type_info* derived = (const __vmi_class_type_info*)aDerivedType;
+
+ const unsigned count = derived->__base_count;
+
+ for ( unsigned i = 0; i < count; i++ )
+ {
+ // Get the base info for this base class
+ const __base_class_type_info bInfo = derived->__base_info[i];
+
+ if ( ! ( bInfo.__offset_flags & bInfo.__public_mask) )
+ {
+ // The base is non-public base, so the remainder of the hierarchy
+ // above this base is of no interest
+ continue;
+ }
+
+ // Get the class type info for this base
+ const __class_type_info* bType = bInfo.__base_type;
+
+ // First check if the type from the list corresponds to requested base
+ // type.
+ if ( (*bType) == (*aBaseType) )
+ {
+ // Match! Convert the pointer to point to the base.
+ _CastUp(bInfo, aDerivedObj, aBaseObj);
+ return true;
+ }
+
+ // No match, we must now recursively delve into superclasses of bType.
+ // To do that, we need to advance the derived class pointer to point to
+ // the current base class as in bInfo.
+ TAny* newDerivedPtr;
+ _CastUp(bInfo, aDerivedObj, &newDerivedPtr);
+
+ // Now go recursive, substituting aDerivedObj with adjusted pointer and bType instead of aDerivedType
+ TBool result = _DoDerivedToBaseConversion(bType, aBaseType, (TAny**)(&newDerivedPtr), aBaseObj);
+
+ // Return only if the match is found, otherwise continue with the loop
+ if ( result )
+ {
+ // Match came back from recursion, pass up.
+ return true;
+ }
+
+ // No match from recursion, advance to next base.
+ }
+ }
+ else
+ {
+ // assert(0);
+ }
+
+ // No match was found for aBaseType in the aDerivedType's ancestry.
+ return false;
+ }
+