diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 90da2d7bc0a..e46916e6d9c 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -1123,7 +1123,26 @@ DIE *DwarfDebug::createMemberDIE(const DIDerivedType &DT) { // This is not a bitfield. addUInt(MemLocationDie, 0, dwarf::DW_FORM_udata, DT.getOffsetInBits() >> 3); - addBlock(MemberDie, dwarf::DW_AT_data_member_location, 0, MemLocationDie); + if (DT.getTag() == dwarf::DW_TAG_inheritance + && DT.isVirtual()) { + + // For C++, virtual base classes are not at fixed offset. Use following + // expression to extract appropriate offset from vtable. + // BaseAddr = ObAddr + *((*ObAddr) - Offset) + + DIEBlock *VBaseLocationDie = new DIEBlock(); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_dup); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_deref); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_constu); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_udata, DT.getOffsetInBits()); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_minus); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_deref); + addUInt(VBaseLocationDie, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_plus); + + addBlock(MemberDie, dwarf::DW_AT_data_member_location, 0, + VBaseLocationDie); + } else + addBlock(MemberDie, dwarf::DW_AT_data_member_location, 0, MemLocationDie); if (DT.isProtected()) addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_flag,