Emit appropriate expression to find virtual base offset.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95242 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 90da2d7..e46916e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1123,7 +1123,26 @@
// 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,