[DebugInfo] Convert intrinsic llvm.dbg.label to MachineInstr.

In order to convert LLVM IR to MachineInstr, we need a new TargetOpcode,
DBG_LABEL, to ‘lower’ intrinsic llvm.dbg.label. The patch
creates this new TargetOpcode and convert intrinsic llvm.dbg.label to
MachineInstr through SelectionDAG.

In SelectionDAG, debug information is stored in SDDbgInfo. We create a
new data member of SDDbgInfo for labels and use the new data member,
SDDbgLabel, to create DBG_LABEL MachineInstr.

The new DBG_LABEL MachineInstr uses label metadata from LLVM IR as its
parameter. So, the backend could get metadata information of labels from
DBG_LABEL MachineInstr.

Differential Revision: https://reviews.llvm.org/D45341

Patch by Hsiangkai Wang.

llvm-svn: 331842

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index fe4cbfc4bf0..8998503bc62 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5230,6 +5230,16 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     }
     return nullptr;
   }
+  case Intrinsic::dbg_label: {
+    const DbgLabelInst &DI = cast<DbgLabelInst>(I);
+    DILabel *Label = DI.getLabel();
+    assert(Label && "Missing label");
+
+    SDDbgLabel *SDV;
+    SDV = DAG.getDbgLabel(Label, dl, SDNodeOrder);
+    DAG.AddDbgLabel(SDV);
+    return nullptr;
+  }
   case Intrinsic::dbg_value: {
     const DbgValueInst &DI = cast<DbgValueInst>(I);
     assert(DI.getVariable() && "Missing variable");