DebugInfo: Add ability to not emit DW_AT_vtable_elem_location for virtual functions.

A virtual index of -1u indicates that the subprogram's virtual index is
unrepresentable (for example, when using the relative vtable ABI), so do
not emit a DW_AT_vtable_elem_location attribute for it.

Differential Revision: http://reviews.llvm.org/D18236

llvm-svn: 263765

1 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index d2cf8effdc2..387921cb46f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1218,10 +1218,12 @@ void DwarfUnit::applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
   unsigned VK = SP->getVirtuality();
   if (VK) {
     addUInt(SPDie, dwarf::DW_AT_virtuality, dwarf::DW_FORM_data1, VK);
-    DIELoc *Block = getDIELoc();
-    addUInt(*Block, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
-    addUInt(*Block, dwarf::DW_FORM_udata, SP->getVirtualIndex());
-    addBlock(SPDie, dwarf::DW_AT_vtable_elem_location, Block);
+    if (SP->getVirtualIndex() != -1u) {
+      DIELoc *Block = getDIELoc();
+      addUInt(*Block, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
+      addUInt(*Block, dwarf::DW_FORM_udata, SP->getVirtualIndex());
+      addBlock(SPDie, dwarf::DW_AT_vtable_elem_location, Block);
+    }
     ContainingTypeMap.insert(
         std::make_pair(&SPDie, resolve(SP->getContainingType())));
   }