Speculatively revert r123032.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123039 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 21 insertions, 5 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index db03ed954e..0ebd94a012 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2257,6 +2257,15 @@ DwarfDebug::collectVariableInfoFromMMITable(const MachineFunction * MF,
   }
 }
 
+/// isDbgValueInUndefinedReg - Return true if debug value, encoded by
+/// DBG_VALUE instruction, is in undefined reg.
+static bool isDbgValueInUndefinedReg(const MachineInstr *MI) {
+  assert (MI->isDebugValue() && "Invalid DBG_VALUE machine instruction!");
+  if (MI->getOperand(0).isReg() && !MI->getOperand(0).getReg())
+    return true;
+  return false;
+}
+
 /// isDbgValueInDefinedReg - Return true if debug value, encoded by
 /// DBG_VALUE instruction, is in a defined reg.
 static bool isDbgValueInDefinedReg(const MachineInstr *MI) {
@@ -2281,7 +2290,7 @@ DwarfDebug::collectVariableInfo(const MachineFunction *MF,
     for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
          II != IE; ++II) {
       const MachineInstr *MInsn = II;
-      if (!MInsn->isDebugValue())
+      if (!MInsn->isDebugValue() || isDbgValueInUndefinedReg(MInsn))
         continue;
       DbgValues.push_back(MInsn);
     }
@@ -2303,18 +2312,19 @@ DwarfDebug::collectVariableInfo(const MachineFunction *MF,
            ME = DbgValues.end(); MI != ME; ++MI) {
       const MDNode *Var =
         (*MI)->getOperand((*MI)->getNumOperands()-1).getMetadata();
-      if (Var == DV && 
+      if (Var == DV && isDbgValueInDefinedReg(*MI) &&
           !PrevMI->isIdenticalTo(*MI))
         MultipleValues.push_back(*MI);
       PrevMI = *MI;
     }
 
-    DbgScope *Scope = NULL;
+    DbgScope *Scope = findDbgScope(MInsn);
+    bool CurFnArg = false;
     if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
         DISubprogram(DV.getContext()).describes(MF->getFunction()))
+      CurFnArg = true;
+    if (!Scope && CurFnArg)
       Scope = CurrentFnDbgScope;
-    else
-      Scope = findDbgScope(MInsn);
     // If variable scope is not found then skip this variable.
     if (!Scope)
       continue;
diff --git a/lib/CodeGen/LiveDebugVariables.cpp b/lib/CodeGen/LiveDebugVariables.cpp
index 2b6a54eab5..baedfc3efb 100644
--- a/lib/CodeGen/LiveDebugVariables.cpp
+++ b/lib/CodeGen/LiveDebugVariables.cpp
@@ -39,6 +39,10 @@
 
 using namespace llvm;
 
+static cl::opt<bool>
+EnableLDV("live-debug-variables",
+          cl::desc("Enable the live debug variables pass"), cl::Hidden);
+
 char LiveDebugVariables::ID = 0;
 
 INITIALIZE_PASS_BEGIN(LiveDebugVariables, "livedebugvars",
@@ -618,6 +622,8 @@ bool LDVImpl::runOnMachineFunction(MachineFunction &mf) {
 }
 
 bool LiveDebugVariables::runOnMachineFunction(MachineFunction &mf) {
+  if (!EnableLDV)
+    return false;
   if (!pImpl)
     pImpl = new LDVImpl(this);
   return static_cast<LDVImpl*>(pImpl)->runOnMachineFunction(mf);