Debug Info: use DW_FORM_ref_addr instead of DW_FORM_ref4 if the referenced DIE

belongs to a different compile unit.

DW_FORM_ref_addr should be used for cross compile-unit reference.

When compiling a large application, we got a dwarfdump verification error where
abstract_origin points to nowhere.

This error can't be reproduced on any testing case in MultiSource.
We may have other cases where we use DW_FORM_ref4 unconditionally.

rdar://problem/13370501


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176882 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/CodeGen/AsmPrinter/DIE.cpp b/lib/CodeGen/AsmPrinter/DIE.cpp
index 4ded2818ed..68d6b6aef7 100644
--- a/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -112,6 +112,17 @@ DIE::~DIE() {
     delete Children[i];
 }
 
+/// Climb up the parent chain to get the compile unit DIE this DIE belongs to.
+DIE *DIE::getCompileUnit() const{
+  DIE *p = getParent();
+  while (p) {
+    if (p->getTag() == dwarf::DW_TAG_compile_unit)
+      return p;
+    p = p->getParent();
+  }
+  return NULL;
+}
+
 #ifndef NDEBUG
 void DIE::print(raw_ostream &O, unsigned IncIndent) {
   IndentCount += IncIndent;