diff --git a/lib/CodeGen/MachineCodeForInstruction.cpp b/lib/CodeGen/MachineCodeForInstruction.cpp
index c50c8b8c6ae..c4b2ee5c9f6 100644
--- a/lib/CodeGen/MachineCodeForInstruction.cpp
+++ b/lib/CodeGen/MachineCodeForInstruction.cpp
@@ -24,10 +24,13 @@
 
 #include "llvm/CodeGen/MachineCodeForInstruction.h"
 #include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Type.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFunctionInfo.h"
 #include "../Target/SparcV9/MachineInstrAnnot.h"
+#include "../Target/SparcV9/SparcV9TmpInstr.h"
 using namespace llvm;
 
 MachineCodeForInstruction &MachineCodeForInstruction::get(const Instruction *I){
@@ -61,3 +64,56 @@ MachineCodeForInstruction::~MachineCodeForInstruction() {
   // Free the CallArgsDescriptor if it exists.
   delete callArgsDesc;
 }
+
+
+CallArgsDescriptor::CallArgsDescriptor(CallInst* _callInstr,
+                                       TmpInstruction* _retAddrReg,
+                                       bool _isVarArgs, bool _noPrototype)
+  : callInstr(_callInstr),
+    funcPtr(isa<Function>(_callInstr->getCalledValue())
+            ? NULL : _callInstr->getCalledValue()),
+    retAddrReg(_retAddrReg),
+    isVarArgs(_isVarArgs),
+    noPrototype(_noPrototype) {
+  unsigned int numArgs = callInstr->getNumOperands();
+  argInfoVec.reserve(numArgs);
+  assert(callInstr->getOperand(0) == callInstr->getCalledValue()
+         && "Operand 0 is ignored in the loop below!");
+  for (unsigned int i=1; i < numArgs; ++i)
+    argInfoVec.push_back(CallArgInfo(callInstr->getOperand(i)));
+
+  // Enter this object in the MachineCodeForInstr object of the CallInst.
+  // This transfers ownership of this object.
+  MachineCodeForInstruction::get(callInstr).setCallArgsDescriptor(this); 
+}
+
+CallInst *CallArgsDescriptor::getReturnValue() const {
+  return (callInstr->getType() == Type::VoidTy? NULL : callInstr);
+}
+
+// Mechanism to get the descriptor for a CALL MachineInstr.
+// We get the LLVM CallInstr from the ret. addr. register argument
+// of the CALL MachineInstr (which is explicit operand #3 for indirect
+// calls or the last implicit operand for direct calls).  We then get
+// the CallArgsDescriptor from the MachineCodeForInstruction object for
+// the CallInstr.
+// This is roundabout but avoids adding a new map or annotation just
+// to keep track of CallArgsDescriptors.
+// 
+CallArgsDescriptor *CallArgsDescriptor::get(const MachineInstr* MI) {
+  const TmpInstruction* retAddrReg =
+    cast<TmpInstruction>(isa<Function>(MI->getOperand(0).getVRegValue())
+                         ? MI->getImplicitRef(MI->getNumImplicitRefs()-1)
+                         : MI->getOperand(2).getVRegValue());
+
+  assert(retAddrReg->getNumOperands() == 1 &&
+         isa<CallInst>(retAddrReg->getOperand(0)) &&
+         "Location of callInstr arg for CALL instr. changed? FIX THIS CODE!");
+
+  const CallInst* callInstr = cast<CallInst>(retAddrReg->getOperand(0));
+
+  CallArgsDescriptor* desc =
+    MachineCodeForInstruction::get(callInstr).getCallArgsDescriptor(); 
+  assert(desc->getCallInst()==callInstr && "Incorrect call args descriptor?");
+  return desc;
+}