[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, 1 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/PatchableFunction.cpp b/llvm/lib/CodeGen/PatchableFunction.cpp
index 0957705b19b..afb4b0a7e17 100644
--- a/llvm/lib/CodeGen/PatchableFunction.cpp
+++ b/llvm/lib/CodeGen/PatchableFunction.cpp
@@ -49,6 +49,7 @@ static bool doesNotGeneratecode(const MachineInstr &MI) {
   case TargetOpcode::EH_LABEL:
   case TargetOpcode::GC_LABEL:
   case TargetOpcode::DBG_VALUE:
+  case TargetOpcode::DBG_LABEL:
     return true;
   }
 }