SDIsel processes llvm.dbg.declare by recording the variable debug information descriptor and its corresponding stack frame index in MachineModuleInfo. This only works if the local variable is "homed" in the stack frame. It does not work for byval parameter, etc.

Added ISD::DECLARE node type to represent llvm.dbg.declare intrinsic. Now the intrinsic calls are lowered into a SDNode and lives on through out the codegen passes.
For now, since all the debugging information recording is done at isel time, when a ISD::DECLARE node is selected, it has the side effect of also recording the variable. This is a short term solution that should be fixed in time.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46659 91177308-0d34-0410-b5e6-96231b3b80d8

27 files changed, 137 insertions, 22 deletions

diff --git a/include/llvm/CodeGen/AsmPrinter.h b/include/llvm/CodeGen/AsmPrinter.h
index cda213cbb9..bbe650b0c2 100644
--- a/include/llvm/CodeGen/AsmPrinter.h
+++ b/include/llvm/CodeGen/AsmPrinter.h
@@ -281,6 +281,10 @@ namespace llvm {
     void printLabel(const MachineInstr *MI) const;
     void printLabel(unsigned Id) const;
 
+    /// printDeclare - This method prints a local variable declaration used by
+    /// debug tables.
+    void printDeclare(const MachineInstr *MI) const;
+
   protected:
     /// EmitZeros - Emit a block of zeros.
     ///
diff --git a/include/llvm/CodeGen/MachineModuleInfo.h b/include/llvm/CodeGen/MachineModuleInfo.h
index ee94e51a2b..8d0a34b1f3 100644
--- a/include/llvm/CodeGen/MachineModuleInfo.h
+++ b/include/llvm/CodeGen/MachineModuleInfo.h
@@ -844,6 +844,10 @@ public:
   /// serialization of a DebugInfoDesc.
   bool Verify(Value *V);
   bool Verify(GlobalVariable *GV);
+
+  /// isVerified - Return true if the specified GV has already been
+  /// verified as a debug information descriptor.
+  bool isVerified(GlobalVariable *GV);
 };
 
 //===----------------------------------------------------------------------===//
@@ -1073,7 +1077,11 @@ public:
   
   /// Verify - Verify that a Value is debug information descriptor.
   ///
-  bool Verify(Value *V);
+  bool Verify(Value *V) { return VR.Verify(V); }
+
+  /// isVerified - Return true if the specified GV has already been
+  /// verified as a debug information descriptor.
+  bool isVerified(GlobalVariable *GV) { return VR.isVerified(GV); }
   
   /// AnalyzeModule - Scan the module for global debug information.
   ///
@@ -1197,7 +1205,7 @@ public:
 
   /// RecordVariable - Indicate the declaration of  a local variable.
   ///
-  void RecordVariable(Value *V, unsigned FrameIndex);
+  void RecordVariable(GlobalValue *GV, unsigned FrameIndex);
   
   /// getRootScope - Return current functions root scope.
   ///
diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index a9ad9a452d..c1a01ea744 100644
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -551,6 +551,10 @@ public:
   /// implement the ComputeNumSignBitsForTarget method in the TargetLowering
   /// class to allow target nodes to be understood.
   unsigned ComputeNumSignBits(SDOperand Op, unsigned Depth = 0) const;
+
+  /// isVerifiedDebugInfoDesc - Returns true if the specified SDOperand has
+  /// been verified as a debug information descriptor.
+  bool isVerifiedDebugInfoDesc(SDOperand Op) const;
   
 private:
   void RemoveNodeFromCSEMaps(SDNode *N);
diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index d0011c3347..fb8db3e221 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -498,6 +498,12 @@ namespace ISD {
     //   Operand #2 : 0 indicates a debug label (e.g. stoppoint), 1 indicates
     //                a EH label, 2 indicates unknown label type.
     LABEL,
+
+    // DECLARE - Represents a llvm.dbg.declare intrinsic. It's used to track
+    // local variable declarations for debugging information. First operand is
+    // a chain, while the next two operands are first two arguments (address
+    // and variable) of a llvm.dbg.declare instruction.
+    DECLARE,
     
     // STACKSAVE - STACKSAVE has one operand, an input chain.  It produces a
     // value, the same type as the pointer type for the system, and an output
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index e62104c921..e18b3665f6 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -47,8 +47,9 @@ public:
     PHI = 0,
     INLINEASM = 1,
     LABEL = 2,
-    EXTRACT_SUBREG = 3,
-    INSERT_SUBREG = 4
+    DECLARE = 3,
+    EXTRACT_SUBREG = 4,
+    INSERT_SUBREG = 5
   };
 
   unsigned getNumOpcodes() const { return NumOpcodes; }
diff --git a/lib/CodeGen/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter.cpp
index 2acf287988..eac574386b 100644
--- a/lib/CodeGen/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter.cpp
@@ -1289,6 +1289,12 @@ void AsmPrinter::printLabel(unsigned Id) const {
   O << "\n" << TAI->getPrivateGlobalPrefix() << "label" << Id << ":\n";
 }
 
+/// printDeclare - This method prints a local variable declaration used by
+/// debug tables.
+void AsmPrinter::printDeclare(const MachineInstr *MI) const {
+  O << "\n";
+}
+
 /// PrintAsmOperand - Print the specified operand of MI, an INLINEASM
 /// instruction, using the specified assembler variant.  Targets should
 /// overried this to format as appropriate.
diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp
index 5edeefbfae..6d285bde04 100644
--- a/lib/CodeGen/MachineModuleInfo.cpp
+++ b/lib/CodeGen/MachineModuleInfo.cpp
@@ -1471,6 +1471,14 @@ bool DIVerifier::Verify(GlobalVariable *GV) {
   return true;
 }
 
+/// isVerified - Return true if the specified GV has already been
+/// verified as a debug information descriptor.
+bool DIVerifier::isVerified(GlobalVariable *GV) {
+  unsigned &ValiditySlot = Validity[GV];
+  if (ValiditySlot) return ValiditySlot == Valid;
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 
 DebugScope::~DebugScope() {
@@ -1554,12 +1562,6 @@ DebugInfoDesc *MachineModuleInfo::getDescFor(Value *V) {
   return DR.Deserialize(V);
 }
 
-/// Verify - Verify that a Value is debug information descriptor.
-///
-bool MachineModuleInfo::Verify(Value *V) {
-  return VR.Verify(V);
-}
-
 /// AnalyzeModule - Scan the module for global debug information.
 ///
 void MachineModuleInfo::AnalyzeModule(Module &M) {
@@ -1657,8 +1659,8 @@ unsigned MachineModuleInfo::RecordRegionEnd(Value *V) {
 
 /// RecordVariable - Indicate the declaration of  a local variable.
 ///
-void MachineModuleInfo::RecordVariable(Value *V, unsigned FrameIndex) {
-  VariableDesc *VD = cast<VariableDesc>(DR.Deserialize(V));
+void MachineModuleInfo::RecordVariable(GlobalValue *GV, unsigned FrameIndex) {
+  VariableDesc *VD = cast<VariableDesc>(DR.Deserialize(GV));
   DebugScope *Scope = getOrCreateScope(VD->getContext());
   DebugVariable *DV = new DebugVariable(VD, FrameIndex);
   Scope->AddVariable(DV);
diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index 41efbef54e..f30d7d455d 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -513,9 +513,9 @@ void PEI::replaceFrameIndices(MachineFunction &Fn) {
     for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
       MachineInstr *MI = I;
 
-      // Remember how much SP has been adjustment to create the call frame.
       if (I->getOpcode() == FrameSetupOpcode ||
           I->getOpcode() == FrameDestroyOpcode) {
+        // Remember how much SP has been adjustment to create the call frame.
         int Size = I->getOperand(0).getImm();
         if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
             (StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
@@ -526,7 +526,10 @@ void PEI::replaceFrameIndices(MachineFunction &Fn) {
         // Visit the instructions created by eliminateCallFramePseudoInstr().
         I = next(PrevI);
         MI = NULL;
-      } else {
+      } else if (I->getOpcode() == TargetInstrInfo::DECLARE)
+        // Ignore it.
+        I++;
+      else {
         I++;
         for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
           if (MI->getOperand(i).isFrameIndex()) {
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index fc726e4c41..4749b76344 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1085,6 +1085,19 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
       break;
     }
     break;
+
+  case ISD::DECLARE:
+    assert(Node->getNumOperands() == 3 && "Invalid DECLARE node!");
+    switch (TLI.getOperationAction(ISD::DECLARE, MVT::Other)) {
+    default: assert(0 && "This action is not supported yet!");
+    case TargetLowering::Legal:
+      Tmp1 = LegalizeOp(Node->getOperand(0));  // Legalize the chain.
+      Tmp2 = LegalizeOp(Node->getOperand(1));  // Legalize the address.
+      Tmp3 = LegalizeOp(Node->getOperand(2));  // Legalize the variable.
+      Result = DAG.UpdateNodeOperands(Result, Tmp1, Tmp2, Tmp3);
+      break;
+    }
+    break;    
     
   case ISD::DEBUG_LOC:
     assert(Node->getNumOperands() == 4 && "Invalid DEBUG_LOC node!");
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
index 3ecd623c81..a165b17dff 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
@@ -736,6 +736,7 @@ void ScheduleDAG::EmitNode(SDNode *Node, unsigned InstanceNo,
     case ISD::EntryToken: // fall thru
     case ISD::TokenFactor:
     case ISD::LABEL:
+    case ISD::DECLARE:
       break;
     case ISD::CopyToReg: {
       unsigned InReg;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6f0e98d825..afb46476aa 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -20,6 +20,7 @@
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/MRegisterInfo.h"
 #include "llvm/Target/TargetData.h"
@@ -1620,6 +1621,16 @@ unsigned SelectionDAG::ComputeNumSignBits(SDOperand Op, unsigned Depth) const{
 }
 
 
+bool SelectionDAG::isVerifiedDebugInfoDesc(SDOperand Op) const {
+  GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Op);
+  if (!GA) return false;
+  GlobalVariable *GV = dyn_cast<GlobalVariable>(GA->getGlobal());
+  if (!GV) return false;
+  MachineModuleInfo *MMI = getMachineModuleInfo();
+  return MMI && MMI->hasDebugInfo() && MMI->isVerified(GV);
+}
+
+
 /// getNode - Gets or creates the specified node.
 ///
 SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT) {
@@ -3700,6 +3711,7 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
   case ISD::MERGE_VALUES:  return "merge_values";
   case ISD::INLINEASM:     return "inlineasm";
   case ISD::LABEL:         return "label";
+  case ISD::DECLARE:       return "declare";
   case ISD::HANDLENODE:    return "handlenode";
   case ISD::FORMAL_ARGUMENTS: return "formal_arguments";
   case ISD::CALL:          return "call";
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 2d883878ce..55231f34a1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2663,12 +2663,10 @@ SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
   case Intrinsic::dbg_declare: {
     MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
     DbgDeclareInst &DI = cast<DbgDeclareInst>(I);
-    if (MMI && DI.getVariable() && MMI->Verify(DI.getVariable())) {
-      SDOperand AddressOp  = getValue(DI.getAddress());
-      if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(AddressOp))
-        MMI->RecordVariable(DI.getVariable(), FI->getIndex());
-    }
-
+    Value *Variable = DI.getVariable();
+    if (MMI && Variable && MMI->Verify(Variable))
+      DAG.setRoot(DAG.getNode(ISD::DECLARE, MVT::Other, getRoot(),
+                              getValue(DI.getAddress()), getValue(Variable)));
     return 0;
   }
     
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index ff299006a6..56bbce7328 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -23,6 +23,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/Target/TargetLowering.h"
diff --git a/lib/Target/Alpha/AlphaISelDAGToDAG.cpp b/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
index 0490f88bb4..2962891ec2 100644
--- a/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
+++ b/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
@@ -18,6 +18,7 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
diff --git a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
index 8bde66300a..488c4e526b 100644
--- a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
+++ b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
@@ -20,6 +20,7 @@
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/Target/TargetOptions.h"
diff --git a/lib/Target/IA64/IA64ISelDAGToDAG.cpp b/lib/Target/IA64/IA64ISelDAGToDAG.cpp
index 338733a8c4..d8e308acb7 100644
--- a/lib/Target/IA64/IA64ISelDAGToDAG.cpp
+++ b/lib/Target/IA64/IA64ISelDAGToDAG.cpp
@@ -18,6 +18,7 @@
 #include "IA64ISelLowering.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/Target/TargetOptions.h"
diff --git a/lib/Target/Mips/MipsISelDAGToDAG.cpp b/lib/Target/Mips/MipsISelDAGToDAG.cpp
index b2ad66670b..88e66fc9a2 100644
--- a/lib/Target/Mips/MipsISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsISelDAGToDAG.cpp
@@ -27,6 +27,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/Target/TargetMachine.h"
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 09fef25196..222792142e 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -20,6 +20,7 @@
 #include "PPCHazardRecognizers.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
diff --git a/lib/Target/Sparc/SparcISelDAGToDAG.cpp b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
index f8dfbe3efa..0d7f40bb2e 100644
--- a/lib/Target/Sparc/SparcISelDAGToDAG.cpp
+++ b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
@@ -19,6 +19,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
diff --git a/lib/Target/Target.td b/lib/Target/Target.td
index 4b1ab2850c..a2669dca4a 100644
--- a/lib/Target/Target.td
+++ b/lib/Target/Target.td
@@ -339,8 +339,15 @@ def LABEL : Instruction {
   let Namespace = "TargetInstrInfo";
   let hasCtrlDep = 1;
 }
+def DECLARE : Instruction {
+  let OutOperandList = (ops);
+  let InOperandList = (ops variable_ops);
+  let AsmString = "";
+  let Namespace = "TargetInstrInfo";
+  let hasCtrlDep = 1;
+}
 def EXTRACT_SUBREG : Instruction {
-        let OutOperandList = (ops variable_ops);
+  let OutOperandList = (ops variable_ops);
   let InOperandList = (ops variable_ops);
   let AsmString = "";
   let Namespace = "TargetInstrInfo";
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index c51cd80cb9..5fc6c5eada 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -29,6 +29,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/Target/TargetMachine.h"
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index b19456e1fd..1093ea8612 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -30,6 +30,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/Support/MathExtras.h"
@@ -279,7 +280,7 @@ X86TargetLowering::X86TargetLowering(TargetMachine &TM)
   setOperationAction(ISD::MEMSET          , MVT::Other, Custom);
   setOperationAction(ISD::MEMCPY          , MVT::Other, Custom);
 
-  // Use the default ISD::LOCATION expansion.
+  // Use the default ISD::LOCATION, ISD::DECLARE expansion.
   setOperationAction(ISD::LOCATION, MVT::Other, Expand);
   // FIXME - use subtarget debug flags
   if (!Subtarget->isTargetDarwin() &&
@@ -3769,6 +3770,9 @@ SDOperand
 X86TargetLowering::LowerGlobalAddress(SDOperand Op, SelectionDAG &DAG) {
   GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
   SDOperand Result = DAG.getTargetGlobalAddress(GV, getPointerTy());
+  // If it's a debug information descriptor, don't mess with it.
+  if (DAG.isVerifiedDebugInfoDesc(Op))
+    return Result;
   Result = DAG.getNode(X86ISD::Wrapper, getPointerTy(), Result);
   // With PIC, the address is actually $g + Offset.
   if (getTargetMachine().getRelocationModel() == Reloc::PIC_ &&
diff --git a/utils/TableGen/AsmWriterEmitter.cpp b/utils/TableGen/AsmWriterEmitter.cpp
index e3d806ade2..eac7bd6326 100644
--- a/utils/TableGen/AsmWriterEmitter.cpp
+++ b/utils/TableGen/AsmWriterEmitter.cpp
@@ -625,6 +625,9 @@ void AsmWriterEmitter::run(std::ostream &O) {
     << "  } else if (MI->getOpcode() == TargetInstrInfo::LABEL) {\n"
     << "    printLabel(MI);\n"
     << "    return true;\n"
+    << "  } else if (MI->getOpcode() == TargetInstrInfo::DECLARE) {\n"
+    << "    printDeclare(MI);\n"
+    << "    return true;\n"
     << "  }\n\n";
   
   O << "  // Emit the opcode for the instruction.\n"
diff --git a/utils/TableGen/CodeEmitterGen.cpp b/utils/TableGen/CodeEmitterGen.cpp
index ddf8eeb84a..60d196cb4a 100644
--- a/utils/TableGen/CodeEmitterGen.cpp
+++ b/utils/TableGen/CodeEmitterGen.cpp
@@ -27,6 +27,7 @@ void CodeEmitterGen::reverseBits(std::vector<Record*> &Insts) {
     if (R->getName() == "PHI" ||
         R->getName() == "INLINEASM" ||
         R->getName() == "LABEL" ||
+        R->getName() == "DECLARE" ||
         R->getName() == "EXTRACT_SUBREG" ||
         R->getName() == "INSERT_SUBREG") continue;
     
@@ -100,6 +101,7 @@ void CodeEmitterGen::run(std::ostream &o) {
     if (R->getName() == "PHI" ||
         R->getName() == "INLINEASM" ||
         R->getName() == "LABEL" ||
+        R->getName() == "DECLARE" ||
         R->getName() == "EXTRACT_SUBREG" ||
         R->getName() == "INSERT_SUBREG") {
       o << "    0U";
@@ -132,6 +134,7 @@ void CodeEmitterGen::run(std::ostream &o) {
     if (InstName == "PHI" ||
         InstName == "INLINEASM" ||
         InstName == "LABEL"||
+        InstName == "DECLARE"||
         InstName == "EXTRACT_SUBREG" ||
         InstName == "INSERT_SUBREG") continue;
     
diff --git a/utils/TableGen/CodeGenTarget.cpp b/utils/TableGen/CodeGenTarget.cpp
index bc758b75cd..b9730a5bd9 100644
--- a/utils/TableGen/CodeGenTarget.cpp
+++ b/utils/TableGen/CodeGenTarget.cpp
@@ -290,6 +290,10 @@ getInstructionsByEnumValue(std::vector<const CodeGenInstruction*>
   if (I == Instructions.end()) throw "Could not find 'LABEL' instruction!";
   const CodeGenInstruction *LABEL = &I->second;
   
+  I = getInstructions().find("DECLARE");
+  if (I == Instructions.end()) throw "Could not find 'DECLARE' instruction!";
+  const CodeGenInstruction *DECLARE = &I->second;
+  
   I = getInstructions().find("EXTRACT_SUBREG");
   if (I == Instructions.end()) 
     throw "Could not find 'EXTRACT_SUBREG' instruction!";
@@ -304,12 +308,14 @@ getInstructionsByEnumValue(std::vector<const CodeGenInstruction*>
   NumberedInstructions.push_back(PHI);
   NumberedInstructions.push_back(INLINEASM);
   NumberedInstructions.push_back(LABEL);
+  NumberedInstructions.push_back(DECLARE);
   NumberedInstructions.push_back(EXTRACT_SUBREG);
   NumberedInstructions.push_back(INSERT_SUBREG);
   for (inst_iterator II = inst_begin(), E = inst_end(); II != E; ++II)
     if (&II->second != PHI &&
         &II->second != INLINEASM &&
         &II->second != LABEL &&
+        &II->second != DECLARE &&
         &II->second != EXTRACT_SUBREG &&
         &II->second != INSERT_SUBREG)
       NumberedInstructions.push_back(&II->second);
diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index ae62c9fcb2..493330a689 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -1779,6 +1779,30 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
      << "                               MVT::Other, Ops, 3);\n"
      << "}\n\n";
 
+  OS << "SDNode *Select_DECLARE(const SDOperand &N) {\n"
+     << "  MachineModuleInfo *MMI = CurDAG->getMachineModuleInfo();\n"
+     << "  SDOperand Chain = N.getOperand(0);\n"
+     << "  SDOperand N1 = N.getOperand(1);\n"
+     << "  SDOperand N2 = N.getOperand(2);\n"
+     << "  if (!isa<FrameIndexSDNode>(N1) || !isa<GlobalAddressSDNode>(N2)) {\n"
+     << "    cerr << \"Cannot yet select llvm.dbg.declare: \";\n"
+     << "    N.Val->dump(CurDAG);\n"
+     << "    abort();\n"
+     << "  }\n"
+     << "  int FI = cast<FrameIndexSDNode>(N1)->getIndex();\n"
+     << "  GlobalValue *GV = cast<GlobalAddressSDNode>(N2)->getGlobal();\n"
+     << "  // FIXME. Handle variable declarations later since it lives on.\n"
+     << "  MMI->RecordVariable(GV, FI);\n"
+     << "  SDOperand Tmp1 = "
+     << "CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());\n"
+     << "  SDOperand Tmp2 = "
+     << "CurDAG->getTargetGlobalAddress(GV, TLI.getPointerTy());\n"
+     << "  AddToISelQueue(Chain);\n"
+     << "  SDOperand Ops[] = { Tmp1, Tmp2, Chain };\n"
+     << "  return CurDAG->getTargetNode(TargetInstrInfo::DECLARE,\n"
+     << "                               MVT::Other, Ops, 3);\n"
+     << "}\n\n";
+
   OS << "SDNode *Select_EXTRACT_SUBREG(const SDOperand &N) {\n"
      << "  SDOperand N0 = N.getOperand(0);\n"
      << "  SDOperand N1 = N.getOperand(1);\n"
@@ -1846,6 +1870,7 @@ void DAGISelEmitter::EmitInstructionSelector(std::ostream &OS) {
      << "  }\n"
      << "  case ISD::INLINEASM: return Select_INLINEASM(N);\n"
      << "  case ISD::LABEL: return Select_LABEL(N);\n"
+     << "  case ISD::DECLARE: return Select_DECLARE(N);\n"
      << "  case ISD::EXTRACT_SUBREG: return Select_EXTRACT_SUBREG(N);\n"
      << "  case ISD::INSERT_SUBREG:  return Select_INSERT_SUBREG(N);\n";
 
diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index 5bf25d1745..3be36266f7 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -409,6 +409,7 @@ void InstrInfoEmitter::emitShiftedValue(Record *R, StringInit *Val,
     if (R->getName() != "PHI" &&
         R->getName() != "INLINEASM" &&
         R->getName() != "LABEL" &&
+        R->getName() != "DECLARE" &&
         R->getName() != "EXTRACT_SUBREG" &&
         R->getName() != "INSERT_SUBREG")
       throw R->getName() + " doesn't have a field named '" +