diff --git a/lib/CodeGen/AsmPrinter/DwarfWriter.cpp b/lib/CodeGen/AsmPrinter/DwarfWriter.cpp
index cb24d7d..848f45e 100644
--- a/lib/CodeGen/AsmPrinter/DwarfWriter.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfWriter.cpp
@@ -70,28 +70,6 @@
 class DIEValue;
 
 //===----------------------------------------------------------------------===//
-/// Utility routines.
-///
-/// getGlobalVariable - Return either a direct or cast Global value.
-///
-static GlobalVariable *getGlobalVariable(Value *V) {
-  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
-    return GV;
-  } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
-    if (CE->getOpcode() == Instruction::BitCast) {
-      return dyn_cast<GlobalVariable>(CE->getOperand(0));
-    } else if (CE->getOpcode() == Instruction::GetElementPtr) {
-      for (unsigned int i=1; i<CE->getNumOperands(); i++) {
-        if (!CE->getOperand(i)->isNullValue())
-          return NULL;
-      }
-      return dyn_cast<GlobalVariable>(CE->getOperand(0));
-    }
-  }
-  return NULL;
-}
-
-//===----------------------------------------------------------------------===//
 /// DWLabel - Labels are used to track locations in the assembler file.
 /// Labels appear in the form @verbatim <prefix><Tag><Number> @endverbatim,
 /// where the tag is a category of label (Ex. location) and number is a value
@@ -3349,61 +3327,6 @@
       DebugTimer->stopTimer();
   }
 
-  /// ValidDebugInfo - Return true if V represents valid debug info value.
-  bool ValidDebugInfo(Value *V, CodeGenOpt::Level OptLevel) {
-    if (!V)
-      return false;
-
-    if (!shouldEmit)
-      return false;
-
-    GlobalVariable *GV = getGlobalVariable(V);
-    if (!GV)
-      return false;
-
-    if (!GV->hasInternalLinkage () && !GV->hasLinkOnceLinkage())
-      return false;
-
-    if (TimePassesIsEnabled)
-      DebugTimer->startTimer();
-
-    DIDescriptor DI(GV);
-
-    // Check current version. Allow Version6 for now.
-    unsigned Version = DI.getVersion();
-    if (Version != LLVMDebugVersion && Version != LLVMDebugVersion6) {
-      if (TimePassesIsEnabled)
-        DebugTimer->stopTimer();
-
-      return false;
-    }
-
-    unsigned Tag = DI.getTag();
-    switch (Tag) {
-    case DW_TAG_variable:
-      assert(DIVariable(GV).Verify() && "Invalid DebugInfo value");
-      break;
-    case DW_TAG_compile_unit:
-      assert(DICompileUnit(GV).Verify() && "Invalid DebugInfo value");
-      break;
-    case DW_TAG_subprogram:
-      assert(DISubprogram(GV).Verify() && "Invalid DebugInfo value");
-      break;
-    case DW_TAG_lexical_block:
-      /// FIXME. This interfers with the qualitfy of generated code when 
-      /// during optimization.
-      if (OptLevel != CodeGenOpt::None)
-        return false;
-    default:
-      break;
-    }
-
-    if (TimePassesIsEnabled)
-      DebugTimer->stopTimer();
-
-    return true;
-  }
-
   /// RecordSourceLine - Records location information and associates it with a 
   /// label. Returns a unique label ID used to generate a label and provide
   /// correspondence to the source line list.
@@ -4752,11 +4675,6 @@
     MMI->EndFunction();
 }
 
-/// ValidDebugInfo - Return true if V represents valid debug info value.
-bool DwarfWriter::ValidDebugInfo(Value *V, CodeGenOpt::Level OptLevel) {
-  return DD && DD->ValidDebugInfo(V, OptLevel);
-}
-
 /// RecordSourceLine - Records location information and associates it with a 
 /// label. Returns a unique label ID used to generate a label and provide
 /// correspondence to the source line list.
@@ -4790,7 +4708,7 @@
 /// ShouldEmitDwarfDebug - Returns true if Dwarf debugging declarations should
 /// be emitted.
 bool DwarfWriter::ShouldEmitDwarfDebug() const {
-  return DD->ShouldEmitDwarfDebug();
+  return DD && DD->ShouldEmitDwarfDebug();
 }
 
 //// RecordInlinedFnStart - Global variable GV is inlined at the location marked
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 58e8490..afcda1f 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -327,21 +327,24 @@
   default: break;
   case Intrinsic::dbg_stoppoint: {
     DbgStopPointInst *SPI = cast<DbgStopPointInst>(I);
-    if (DW && DW->ValidDebugInfo(SPI->getContext(), CodeGenOpt::None)) {
+    if (DIDescriptor::ValidDebugInfo(SPI->getContext(), CodeGenOpt::None)) {
       DICompileUnit CU(cast<GlobalVariable>(SPI->getContext()));
       unsigned Line = SPI->getLine();
       unsigned Col = SPI->getColumn();
-      unsigned ID = DW->RecordSourceLine(Line, Col, CU);
       unsigned Idx = MF.getOrCreateDebugLocID(CU.getGV(), Line, Col);
       setCurDebugLoc(DebugLoc::get(Idx));
-      const TargetInstrDesc &II = TII.get(TargetInstrInfo::DBG_LABEL);
-      BuildMI(MBB, DL, II).addImm(ID);
+      if (DW && DW->ShouldEmitDwarfDebug()) {
+        unsigned ID = DW->RecordSourceLine(Line, Col, CU);
+        const TargetInstrDesc &II = TII.get(TargetInstrInfo::DBG_LABEL);
+        BuildMI(MBB, DL, II).addImm(ID);
+      }
     }
     return true;
   }
   case Intrinsic::dbg_region_start: {
     DbgRegionStartInst *RSI = cast<DbgRegionStartInst>(I);
-    if (DW && DW->ValidDebugInfo(RSI->getContext(), CodeGenOpt::None)) {
+    if (DIDescriptor::ValidDebugInfo(RSI->getContext(), CodeGenOpt::None) &&
+        DW && DW->ShouldEmitDwarfDebug()) {
       unsigned ID = 
         DW->RecordRegionStart(cast<GlobalVariable>(RSI->getContext()));
       const TargetInstrDesc &II = TII.get(TargetInstrInfo::DBG_LABEL);
@@ -351,7 +354,8 @@
   }
   case Intrinsic::dbg_region_end: {
     DbgRegionEndInst *REI = cast<DbgRegionEndInst>(I);
-    if (DW && DW->ValidDebugInfo(REI->getContext(), CodeGenOpt::None)) {
+    if (DIDescriptor::ValidDebugInfo(REI->getContext(), CodeGenOpt::None) &&
+        DW && DW->ShouldEmitDwarfDebug()) {
      unsigned ID = 0;
      DISubprogram Subprogram(cast<GlobalVariable>(REI->getContext()));
      if (!Subprogram.isNull() && !Subprogram.describes(MF.getFunction())) {
@@ -373,43 +377,46 @@
     return true;
   }
   case Intrinsic::dbg_func_start: {
-    if (!DW) return true;
     DbgFuncStartInst *FSI = cast<DbgFuncStartInst>(I);
     Value *SP = FSI->getSubprogram();
+    if (!DIDescriptor::ValidDebugInfo(SP, CodeGenOpt::None))
+      return true;
 
-    if (DW->ValidDebugInfo(SP, CodeGenOpt::None)) {
-      // llvm.dbg.func.start implicitly defines a dbg_stoppoint which is what
-      // (most?) gdb expects.
-      DebugLoc PrevLoc = DL;
-      DISubprogram Subprogram(cast<GlobalVariable>(SP));
-      DICompileUnit CompileUnit = Subprogram.getCompileUnit();
+    // llvm.dbg.func.start implicitly defines a dbg_stoppoint which is what
+    // (most?) gdb expects.
+    DebugLoc PrevLoc = DL;
+    DISubprogram Subprogram(cast<GlobalVariable>(SP));
+    DICompileUnit CompileUnit = Subprogram.getCompileUnit();
 
-      if (!Subprogram.describes(MF.getFunction())) {
-        // This is a beginning of an inlined function.
-        
-        // If llvm.dbg.func.start is seen in a new block before any
-        // llvm.dbg.stoppoint intrinsic then the location info is unknown.
-        // FIXME : Why DebugLoc is reset at the beginning of each block ?
-        if (PrevLoc.isUnknown())
-          return true;
-        // Record the source line.
-        unsigned Line = Subprogram.getLineNumber();
+    if (!Subprogram.describes(MF.getFunction())) {
+      // This is a beginning of an inlined function.
+
+      // If llvm.dbg.func.start is seen in a new block before any
+      // llvm.dbg.stoppoint intrinsic then the location info is unknown.
+      // FIXME : Why DebugLoc is reset at the beginning of each block ?
+      if (PrevLoc.isUnknown())
+        return true;
+      // Record the source line.
+      unsigned Line = Subprogram.getLineNumber();
+      setCurDebugLoc(DebugLoc::get(MF.getOrCreateDebugLocID(
+                                              CompileUnit.getGV(), Line, 0)));
+
+      if (DW && DW->ShouldEmitDwarfDebug()) {
         unsigned LabelID = DW->RecordSourceLine(Line, 0, CompileUnit);
-        setCurDebugLoc(DebugLoc::get(MF.getOrCreateDebugLocID(
-                                                CompileUnit.getGV(), Line, 0)));
-
         const TargetInstrDesc &II = TII.get(TargetInstrInfo::DBG_LABEL);
         BuildMI(MBB, DL, II).addImm(LabelID);
         DebugLocTuple PrevLocTpl = MF.getDebugLocTuple(PrevLoc);
-        DW->RecordInlinedFnStart(FSI, Subprogram, LabelID, 
+        DW->RecordInlinedFnStart(FSI, Subprogram, LabelID,
                                  DICompileUnit(PrevLocTpl.CompileUnit),
                                  PrevLocTpl.Line,
                                  PrevLocTpl.Col);
-      } else {
-        // Record the source line.
-        unsigned Line = Subprogram.getLineNumber();
-        setCurDebugLoc(DebugLoc::get(MF.getOrCreateDebugLocID(
-                                                CompileUnit.getGV(), Line, 0)));
+      }
+    } else {
+      // Record the source line.
+      unsigned Line = Subprogram.getLineNumber();
+      setCurDebugLoc(DebugLoc::get(MF.getOrCreateDebugLocID(
+                                              CompileUnit.getGV(), Line, 0)));
+      if (DW && DW->ShouldEmitDwarfDebug()) {
         DW->RecordSourceLine(Line, 0, CompileUnit);
         // llvm.dbg.func_start also defines beginning of function scope.
         DW->RecordRegionStart(cast<GlobalVariable>(FSI->getSubprogram()));
@@ -421,7 +428,8 @@
   case Intrinsic::dbg_declare: {
     DbgDeclareInst *DI = cast<DbgDeclareInst>(I);
     Value *Variable = DI->getVariable();
-    if (DW && DW->ValidDebugInfo(Variable, CodeGenOpt::None)) {
+    if (DIDescriptor::ValidDebugInfo(Variable, CodeGenOpt::None) &&
+        DW && DW->ShouldEmitDwarfDebug()) {
       // Determine the address of the declared object.
       Value *Address = DI->getAddress();
       if (BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index aecfbb4..acdb043 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -331,11 +331,10 @@
           switch (F->getIntrinsicID()) {
           default: break;
           case Intrinsic::dbg_stoppoint: {
-            DwarfWriter *DW = DAG.getDwarfWriter();
             DbgStopPointInst *SPI = cast<DbgStopPointInst>(I);
 
-            if (DW && DW->ValidDebugInfo(SPI->getContext(),
-                                         CodeGenOpt::Default)) {
+            if (DIDescriptor::ValidDebugInfo(SPI->getContext(),
+                                             CodeGenOpt::Default)) {
               DICompileUnit CU(cast<GlobalVariable>(SPI->getContext()));
               unsigned idx = MF->getOrCreateDebugLocID(CU.getGV(),
                                                        SPI->getLine(),
@@ -346,18 +345,15 @@
             break;
           }
           case Intrinsic::dbg_func_start: {
-            DwarfWriter *DW = DAG.getDwarfWriter();
-            if (DW) {
-              DbgFuncStartInst *FSI = cast<DbgFuncStartInst>(I);
-              Value *SP = FSI->getSubprogram();
+            DbgFuncStartInst *FSI = cast<DbgFuncStartInst>(I);
+            Value *SP = FSI->getSubprogram();
 
-              if (DW->ValidDebugInfo(SP, CodeGenOpt::Default)) {
-                DISubprogram Subprogram(cast<GlobalVariable>(SP));
-                DICompileUnit CU(Subprogram.getCompileUnit());
-                unsigned Line = Subprogram.getLineNumber();
-                DL = DebugLoc::get(MF->getOrCreateDebugLocID(CU.getGV(),
-                                                             Line, 0));
-              }
+            if (DIDescriptor::ValidDebugInfo(SP, CodeGenOpt::Default)) {
+              DISubprogram Subprogram(cast<GlobalVariable>(SP));
+              DICompileUnit CU(Subprogram.getCompileUnit());
+              unsigned Line = Subprogram.getLineNumber();
+              DL = DebugLoc::get(MF->getOrCreateDebugLocID(CU.getGV(),
+                                                           Line, 0));
             }
 
             break;
@@ -3890,9 +3886,8 @@
     return 0;
   }
   case Intrinsic::dbg_stoppoint: {
-    DwarfWriter *DW = DAG.getDwarfWriter();
     DbgStopPointInst &SPI = cast<DbgStopPointInst>(I);
-    if (DW && DW->ValidDebugInfo(SPI.getContext(), OptLevel)) {
+    if (DIDescriptor::ValidDebugInfo(SPI.getContext(), OptLevel)) {
       MachineFunction &MF = DAG.getMachineFunction();
       if (OptLevel == CodeGenOpt::None)
         DAG.setRoot(DAG.getDbgStopPoint(getRoot(),
@@ -3910,7 +3905,8 @@
     DwarfWriter *DW = DAG.getDwarfWriter();
     DbgRegionStartInst &RSI = cast<DbgRegionStartInst>(I);
 
-    if (DW && DW->ValidDebugInfo(RSI.getContext(), OptLevel)) {
+    if (DIDescriptor::ValidDebugInfo(RSI.getContext(), OptLevel) &&
+        DW && DW->ShouldEmitDwarfDebug()) {
       unsigned LabelID =
         DW->RecordRegionStart(cast<GlobalVariable>(RSI.getContext()));
       DAG.setRoot(DAG.getLabel(ISD::DBG_LABEL, getCurDebugLoc(),
@@ -3923,7 +3919,8 @@
     DwarfWriter *DW = DAG.getDwarfWriter();
     DbgRegionEndInst &REI = cast<DbgRegionEndInst>(I);
 
-    if (DW && DW->ValidDebugInfo(REI.getContext(), OptLevel)) {
+    if (DIDescriptor::ValidDebugInfo(REI.getContext(), OptLevel) &&
+        DW && DW->ShouldEmitDwarfDebug()) {
       MachineFunction &MF = DAG.getMachineFunction();
       DISubprogram Subprogram(cast<GlobalVariable>(REI.getContext()));
       std::string SPName;
@@ -3955,84 +3952,87 @@
   }
   case Intrinsic::dbg_func_start: {
     DwarfWriter *DW = DAG.getDwarfWriter();
-    if (!DW) return 0;
     DbgFuncStartInst &FSI = cast<DbgFuncStartInst>(I);
     Value *SP = FSI.getSubprogram();
-    if (SP && DW->ValidDebugInfo(SP, OptLevel)) {
-      MachineFunction &MF = DAG.getMachineFunction();
-      if (OptLevel == CodeGenOpt::None) {
-        // llvm.dbg.func.start implicitly defines a dbg_stoppoint which is what
-        // (most?) gdb expects.
-        DebugLoc PrevLoc = CurDebugLoc;
-        DISubprogram Subprogram(cast<GlobalVariable>(SP));
-        DICompileUnit CompileUnit = Subprogram.getCompileUnit();
-        
-        if (!Subprogram.describes(MF.getFunction())) {
-          // This is a beginning of an inlined function.
+    if (!DIDescriptor::ValidDebugInfo(SP, OptLevel))
+      return 0;
 
-          // If llvm.dbg.func.start is seen in a new block before any
-          // llvm.dbg.stoppoint intrinsic then the location info is unknown.
-          // FIXME : Why DebugLoc is reset at the beginning of each block ?
-          if (PrevLoc.isUnknown())
-            return 0;
+    MachineFunction &MF = DAG.getMachineFunction();
+    if (OptLevel == CodeGenOpt::None) {
+      // llvm.dbg.func.start implicitly defines a dbg_stoppoint which is what
+      // (most?) gdb expects.
+      DebugLoc PrevLoc = CurDebugLoc;
+      DISubprogram Subprogram(cast<GlobalVariable>(SP));
+      DICompileUnit CompileUnit = Subprogram.getCompileUnit();
 
-          // Record the source line.
-          unsigned Line = Subprogram.getLineNumber();
+      if (!Subprogram.describes(MF.getFunction())) {
+        // This is a beginning of an inlined function.
+
+        // If llvm.dbg.func.start is seen in a new block before any
+        // llvm.dbg.stoppoint intrinsic then the location info is unknown.
+        // FIXME : Why DebugLoc is reset at the beginning of each block ?
+        if (PrevLoc.isUnknown())
+          return 0;
+
+        // Record the source line.
+        unsigned Line = Subprogram.getLineNumber();
+        setCurDebugLoc(DebugLoc::get(
+                     MF.getOrCreateDebugLocID(CompileUnit.getGV(), Line, 0)));
+
+        if (DW && DW->ShouldEmitDwarfDebug()) {
           unsigned LabelID = DW->RecordSourceLine(Line, 0, CompileUnit);
-          setCurDebugLoc(DebugLoc::get(
-                       MF.getOrCreateDebugLocID(CompileUnit.getGV(), Line, 0)));
-
           DAG.setRoot(DAG.getLabel(ISD::DBG_LABEL, getCurDebugLoc(),
                                    getRoot(), LabelID));
           DebugLocTuple PrevLocTpl = MF.getDebugLocTuple(PrevLoc);
-          DW->RecordInlinedFnStart(&FSI, Subprogram, LabelID, 
+          DW->RecordInlinedFnStart(&FSI, Subprogram, LabelID,
                                    DICompileUnit(PrevLocTpl.CompileUnit),
                                    PrevLocTpl.Line,
                                    PrevLocTpl.Col);
-        } else {
-          // Record the source line.
-          unsigned Line = Subprogram.getLineNumber();
-          setCurDebugLoc(DebugLoc::get(
-                       MF.getOrCreateDebugLocID(CompileUnit.getGV(), Line, 0)));
+        }
+      } else {
+        // Record the source line.
+        unsigned Line = Subprogram.getLineNumber();
+        setCurDebugLoc(DebugLoc::get(
+                     MF.getOrCreateDebugLocID(CompileUnit.getGV(), Line, 0)));
+        if (DW && DW->ShouldEmitDwarfDebug()) {
           DW->RecordSourceLine(Line, 0, CompileUnit);
           // llvm.dbg.func_start also defines beginning of function scope.
           DW->RecordRegionStart(cast<GlobalVariable>(FSI.getSubprogram()));
         }
-      } else {
-        DISubprogram Subprogram(cast<GlobalVariable>(SP));
-        
-        std::string SPName;
-        Subprogram.getLinkageName(SPName);
-        if (!SPName.empty() 
-            && strcmp(SPName.c_str(), MF.getFunction()->getNameStart())) {
-          // This is beginning of inlined function. Debugging information for
-          // inlined function is not handled yet (only supported by FastISel).
-          return 0;
-        }
-
-        // llvm.dbg.func.start implicitly defines a dbg_stoppoint which is
-        // what (most?) gdb expects.
-        DICompileUnit CompileUnit = Subprogram.getCompileUnit();
-        
-        // Record the source line but does not create a label for the normal
-        // function start. It will be emitted at asm emission time. However,
-        // create a label if this is a beginning of inlined function.
-        unsigned Line = Subprogram.getLineNumber();
-        setCurDebugLoc(DebugLoc::get(
-                       MF.getOrCreateDebugLocID(CompileUnit.getGV(), Line, 0)));
-        // FIXME -  Start new region because llvm.dbg.func_start also defines 
-        // beginning of function scope.
       }
+    } else {
+      DISubprogram Subprogram(cast<GlobalVariable>(SP));
+
+      std::string SPName;
+      Subprogram.getLinkageName(SPName);
+      if (!SPName.empty()
+          && strcmp(SPName.c_str(), MF.getFunction()->getNameStart())) {
+        // This is beginning of inlined function. Debugging information for
+        // inlined function is not handled yet (only supported by FastISel).
+        return 0;
+      }
+
+      // llvm.dbg.func.start implicitly defines a dbg_stoppoint which is
+      // what (most?) gdb expects.
+      DICompileUnit CompileUnit = Subprogram.getCompileUnit();
+
+      // Record the source line but does not create a label for the normal
+      // function start. It will be emitted at asm emission time. However,
+      // create a label if this is a beginning of inlined function.
+      unsigned Line = Subprogram.getLineNumber();
+      setCurDebugLoc(DebugLoc::get(
+                     MF.getOrCreateDebugLocID(CompileUnit.getGV(), Line, 0)));
+      // FIXME -  Start new region because llvm.dbg.func_start also defines
+      // beginning of function scope.
     }
 
     return 0;
   }
   case Intrinsic::dbg_declare: {
     if (OptLevel == CodeGenOpt::None) {
-      DwarfWriter *DW = DAG.getDwarfWriter();
       DbgDeclareInst &DI = cast<DbgDeclareInst>(I);
       Value *Variable = DI.getVariable();
-      if (DW && DW->ValidDebugInfo(Variable, OptLevel))
+      if (DIDescriptor::ValidDebugInfo(Variable, OptLevel))
         DAG.setRoot(DAG.getNode(ISD::DECLARE, dl, MVT::Other, getRoot(),
                                 getValue(DI.getAddress()), getValue(Variable)));
     } else {