Convert Alpha and Mips to use a MachineFunctionInfo subclass to

carry GlobalBaseReg, and GlobalRetAddr too in Alpha's case. This
eliminates the need for them to search through the
MachineRegisterInfo livein list in order to identify these
virtual registers. EmitLiveInCopies is now the only user of the
virtual register portion of MachineRegisterInfo's livein data.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72802 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 63 insertions, 23 deletions

diff --git a/lib/Target/Mips/MipsISelDAGToDAG.cpp b/lib/Target/Mips/MipsISelDAGToDAG.cpp
index f05ac70..53de1bb 100644
--- a/lib/Target/Mips/MipsISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsISelDAGToDAG.cpp
@@ -70,7 +70,19 @@ private:
   // Include the pieces autogenerated from the target description.
   #include "MipsGenDAGISel.inc"
 
-  SDValue getGlobalBaseReg();
+  /// getTargetMachine - Return a reference to the TargetMachine, casted
+  /// to the target-specific type.
+  const MipsTargetMachine &getTargetMachine() {
+    return static_cast<const MipsTargetMachine &>(TM);
+  }
+
+  /// getInstrInfo - Return a reference to the TargetInstrInfo, casted
+  /// to the target-specific type.
+  const MipsInstrInfo *getInstrInfo() {
+    return getTargetMachine().getInstrInfo();
+  }
+
+  SDNode *getGlobalBaseReg();
   SDNode *Select(SDValue N);
 
   // Complex Pattern.
@@ -116,19 +128,10 @@ InstructionSelect()
 
 /// getGlobalBaseReg - Output the instructions required to put the
 /// GOT address into a register.
-SDValue MipsDAGToDAGISel::getGlobalBaseReg() {
-  MachineFunction* MF = BB->getParent();
-  unsigned GP = 0;
-  for(MachineRegisterInfo::livein_iterator ii = MF->getRegInfo().livein_begin(),
-        ee = MF->getRegInfo().livein_end(); ii != ee; ++ii)
-    if (ii->first == Mips::GP) {
-      GP = ii->second;
-      break;
-    }
-  assert(GP && "GOT PTR not in liveins");
-  // FIXME is there a sensible place to get debug info for this?
-  return CurDAG->getCopyFromReg(CurDAG->getEntryNode(), 
-                                DebugLoc::getUnknownLoc(), GP, MVT::i32);
+SDNode *MipsDAGToDAGISel::getGlobalBaseReg() {
+  MachineFunction *MF = BB->getParent();
+  unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
+  return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
 }
 
 /// ComplexPattern used on MipsInstrInfo
@@ -321,11 +324,8 @@ Select(SDValue N)
     }
 
     // Get target GOT address.
-    case ISD::GLOBAL_OFFSET_TABLE: {
-      SDValue Result = getGlobalBaseReg();
-      ReplaceUses(N, Result);
-      return NULL;
-    }
+    case ISD::GLOBAL_OFFSET_TABLE:
+      return getGlobalBaseReg();
 
     /// Handle direct and indirect calls when using PIC. On PIC, when 
     /// GOT is smaller than about 64k (small code) the GA target is 
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 9281940..4517cfc 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -941,9 +941,6 @@ LowerFORMAL_ARGUMENTS(SDValue Op, SelectionDAG &DAG)
 
   unsigned StackReg = MF.getTarget().getRegisterInfo()->getFrameRegister(MF);
 
-  // GP must be live into PIC and non-PIC call target.
-  AddLiveIn(MF, Mips::GP, Mips::CPURegsRegisterClass);
-
   // Assign locations to all of the incoming arguments.
   SmallVector<CCValAssign, 16> ArgLocs;
   CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
diff --git a/lib/Target/Mips/MipsInstrInfo.cpp b/lib/Target/Mips/MipsInstrInfo.cpp
index 6225fa9..92af973 100644
--- a/lib/Target/Mips/MipsInstrInfo.cpp
+++ b/lib/Target/Mips/MipsInstrInfo.cpp
@@ -13,8 +13,10 @@
 
 #include "MipsInstrInfo.h"
 #include "MipsTargetMachine.h"
+#include "MipsMachineFunction.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "MipsGenInstrInfo.inc"
 
 using namespace llvm;
@@ -621,3 +623,30 @@ ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const
   Cond[0].setImm(GetOppositeBranchCondition((Mips::CondCode)Cond[0].getImm()));
   return false;
 }
+
+/// getGlobalBaseReg - Return a virtual register initialized with the
+/// the global base register value. Output instructions required to
+/// initialize the register in the function entry block, if necessary.
+///
+unsigned MipsInstrInfo::getGlobalBaseReg(MachineFunction *MF) const {
+  MipsFunctionInfo *MipsFI = MF->getInfo<MipsFunctionInfo>();
+  unsigned GlobalBaseReg = MipsFI->getGlobalBaseReg();
+  if (GlobalBaseReg != 0)
+    return GlobalBaseReg;
+
+  // Insert the set of GlobalBaseReg into the first MBB of the function
+  MachineBasicBlock &FirstMBB = MF->front();
+  MachineBasicBlock::iterator MBBI = FirstMBB.begin();
+  MachineRegisterInfo &RegInfo = MF->getRegInfo();
+  const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
+
+  GlobalBaseReg = RegInfo.createVirtualRegister(Mips::CPURegsRegisterClass);
+  bool Ok = TII->copyRegToReg(FirstMBB, MBBI, GlobalBaseReg, Mips::GP,
+                              Mips::CPURegsRegisterClass,
+                              Mips::CPURegsRegisterClass);
+  assert(Ok && "Couldn't assign to global base register!");
+  RegInfo.addLiveIn(Mips::GP);
+
+  MipsFI->setGlobalBaseReg(GlobalBaseReg);
+  return GlobalBaseReg;
+}
diff --git a/lib/Target/Mips/MipsInstrInfo.h b/lib/Target/Mips/MipsInstrInfo.h
index 334244e..6655c67 100644
--- a/lib/Target/Mips/MipsInstrInfo.h
+++ b/lib/Target/Mips/MipsInstrInfo.h
@@ -216,6 +216,12 @@ public:
   /// Insert nop instruction when hazard condition is found
   virtual void insertNoop(MachineBasicBlock &MBB, 
                           MachineBasicBlock::iterator MI) const;
+
+  /// getGlobalBaseReg - Return a virtual register initialized with the
+  /// the global base register value. Output instructions required to
+  /// initialize the register in the function entry block, if necessary.
+  ///
+  unsigned getGlobalBaseReg(MachineFunction *MF) const;
 };
 
 }
diff --git a/lib/Target/Mips/MipsMachineFunction.h b/lib/Target/Mips/MipsMachineFunction.h
index b95394e..ac3cdfd 100644
--- a/lib/Target/Mips/MipsMachineFunction.h
+++ b/lib/Target/Mips/MipsMachineFunction.h
@@ -75,11 +75,16 @@ private:
   /// holds the virtual register into which the sret argument is passed.
   unsigned SRetReturnReg;
 
+  /// GlobalBaseReg - keeps track of the virtual register initialized for
+  /// use as the global base register. This is used for PIC in some PIC
+  /// relocation models.
+  unsigned GlobalBaseReg;
+
 public:
   MipsFunctionInfo(MachineFunction& MF) 
   : FPStackOffset(0), RAStackOffset(0), CPUTopSavedRegOff(0), 
     FPUTopSavedRegOff(0), GPHolder(-1,-1), HasLoadArgs(false), 
-    HasStoreVarArgs(false), SRetReturnReg(0)
+    HasStoreVarArgs(false), SRetReturnReg(0), GlobalBaseReg(0)
   {}
 
   int getFPStackOffset() const { return FPStackOffset; }
@@ -124,6 +129,9 @@ public:
 
   unsigned getSRetReturnReg() const { return SRetReturnReg; }
   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
+
+  unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
+  void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }
 };
 
 } // end of namespace llvm