Emit 'no line' information for interesting 'orphan' instructions.

DWARF specifies that "line 0" really means "no appropriate source
location" in the line table.  Use this for branch targets and some
other cases that have no specified source location, to prevent
inheriting unfortunate line numbers from physically preceding
instructions (which might be from completely unrelated source).

Differential Revision: http://reviews.llvm.org/D24180

llvm-svn: 288212

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
index d30f106a939..5607242a7f1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -201,8 +201,10 @@ void DebugHandlerBase::endInstruction() {
   assert(CurMI != nullptr);
   // Don't create a new label after DBG_VALUE instructions.
   // They don't generate code.
-  if (!CurMI->isDebugValue())
+  if (!CurMI->isDebugValue()) {
     PrevLabel = nullptr;
+    PrevInstBB = CurMI->getParent();
+  }
 
   DenseMap<const MachineInstr *, MCSymbol *>::iterator I =
       LabelsAfterInsn.find(CurMI);