Reapply an improved version of r180816/180817.

Change the informal convention of DBG_VALUE machine instructions so that
we can express a register-indirect address with an offset of 0.
The old convention was that a DBG_VALUE is a register-indirect value if
the offset (operand 1) is nonzero. The new convention is that a DBG_VALUE
is register-indirect if the first operand is a register and the second
operand is an immediate. For plain register values the combination reg,
reg is used. MachineInstrBuilder::BuildMI knows how to build the new
DBG_VALUES.

rdar://problem/13658587

llvm-svn: 185966

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 2a1ded04b48..e9bafc9242e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4422,11 +4422,15 @@ SelectionDAGBuilder::EmitFuncArgumentDbgValue(const Value *V, MDNode *Variable,
     return false;
 
   if (Op->isReg())
-    Op->setIsDebug();
-
-  FuncInfo.ArgDbgValues.push_back(
+    FuncInfo.ArgDbgValues.push_back(BuildMI(MF, getCurDebugLoc(),
+                                            TII->get(TargetOpcode::DBG_VALUE),
+                                            /* IsIndirect */ Offset != 0,
+                                            Op->getReg(), Offset, Variable));
+  else
+    FuncInfo.ArgDbgValues.push_back(
       BuildMI(MF, getCurDebugLoc(), TII->get(TargetOpcode::DBG_VALUE))
           .addOperand(*Op).addImm(Offset).addMetadata(Variable));
+
   return true;
 }