From b9472338182aa0faafbcf48a05b637aed457af43 Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@gmail.com>
Date: Fri, 13 Feb 2015 00:39:27 +0000
Subject: [PATCH] The return save offset can be computed at initialization time
 - do so and save the value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228996 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PowerPC/PPCFrameLowering.cpp | 13 ++++++++++---
 lib/Target/PowerPC/PPCFrameLowering.h   |  8 ++------
 lib/Target/PowerPC/PPCISelLowering.cpp  | 15 +++++++--------
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/lib/Target/PowerPC/PPCFrameLowering.cpp b/lib/Target/PowerPC/PPCFrameLowering.cpp
index 95143d54c7e..33f66fed81c 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -36,10 +36,17 @@ static const uint16_t VRRegNo[] = {
  PPC::V24, PPC::V25, PPC::V26, PPC::V27, PPC::V28, PPC::V29, PPC::V30, PPC::V31
 };
 
+static unsigned computeReturnSaveOffset(const PPCSubtarget &STI) {
+  if (STI.isDarwinABI())
+    return STI.isPPC64() ? 16 : 8;
+  // SVR4 ABI:
+  return STI.isPPC64() ? 16 : 4;
+}
+
 PPCFrameLowering::PPCFrameLowering(const PPCSubtarget &STI)
     : TargetFrameLowering(TargetFrameLowering::StackGrowsDown,
                           (STI.hasQPX() || STI.isBGQ()) ? 32 : 16, 0),
-      Subtarget(STI) {}
+      Subtarget(STI), ReturnSaveOffset(computeReturnSaveOffset(Subtarget)) {}
 
 // With the SVR4 ABI, callee-saved registers have fixed offsets on the stack.
 const PPCFrameLowering::SpillSlot *PPCFrameLowering::getCalleeSavedSpillSlots(
@@ -598,7 +605,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF) const {
   assert((isPPC64 || !isSVR4ABI || !(!FrameSize && (MustSaveLR || HasFP))) &&
          "FrameSize must be >0 to save/restore the FP or LR for 32-bit SVR4.");
 
-  int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI);
+  int LROffset = getReturnSaveOffset();
 
   int FPOffset = 0;
   if (HasFP) {
@@ -936,7 +943,7 @@ void PPCFrameLowering::emitEpilogue(MachineFunction &MF,
   const MCInstrDesc& AddInst = TII.get( isPPC64 ? PPC::ADD8
                                                 : PPC::ADD4 );
 
-  int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI);
+  int LROffset = getReturnSaveOffset();
 
   int FPOffset = 0;
   if (HasFP) {
diff --git a/lib/Target/PowerPC/PPCFrameLowering.h b/lib/Target/PowerPC/PPCFrameLowering.h
index c4825882182..32053a186ff 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.h
+++ b/lib/Target/PowerPC/PPCFrameLowering.h
@@ -23,6 +23,7 @@ class PPCSubtarget;
 
 class PPCFrameLowering: public TargetFrameLowering {
   const PPCSubtarget &Subtarget;
+  const unsigned ReturnSaveOffset;
 
 public:
   PPCFrameLowering(const PPCSubtarget &STI);
@@ -67,12 +68,7 @@ public:
 
   /// getReturnSaveOffset - Return the previous frame offset to save the
   /// return address.
-  static unsigned getReturnSaveOffset(bool isPPC64, bool isDarwinABI) {
-    if (isDarwinABI)
-      return isPPC64 ? 16 : 8;
-    // SVR4 ABI:
-    return isPPC64 ? 16 : 4;
-  }
+  unsigned getReturnSaveOffset() const { return ReturnSaveOffset; }
 
   /// getTOCSaveOffset - Return the previous frame offset to save the
   /// TOC register -- 64-bit SVR4 ABI only.
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 15a0818c816..70938dd948d 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -3472,8 +3472,10 @@ static SDValue EmitTailCallStoreFPAndRetAddr(SelectionDAG &DAG,
   if (SPDiff) {
     // Calculate the new stack slot for the return address.
     int SlotSize = isPPC64 ? 8 : 4;
-    int NewRetAddrLoc = SPDiff + PPCFrameLowering::getReturnSaveOffset(isPPC64,
-                                                                   isDarwinABI);
+    int NewRetAddrLoc = SPDiff +
+                        MF.getSubtarget<PPCSubtarget>()
+                            .getFrameLowering()
+                            ->getReturnSaveOffset();
     int NewRetAddr = MF.getFrameInfo()->CreateFixedObject(SlotSize,
                                                           NewRetAddrLoc, true);
     EVT VT = isPPC64 ? MVT::i64 : MVT::i32;
@@ -5308,7 +5310,6 @@ SDValue
 PPCTargetLowering::getReturnAddrFrameIndex(SelectionDAG & DAG) const {
   MachineFunction &MF = DAG.getMachineFunction();
   bool isPPC64 = Subtarget.isPPC64();
-  bool isDarwinABI = Subtarget.isDarwinABI();
   EVT PtrVT = DAG.getTargetLoweringInfo().getPointerTy();
 
   // Get current frame pointer save index.  The users of this index will be
@@ -5319,7 +5320,7 @@ PPCTargetLowering::getReturnAddrFrameIndex(SelectionDAG & DAG) const {
   // If the frame pointer save index hasn't been defined yet.
   if (!RASI) {
     // Find out what the fix offset of the frame pointer save area.
-    int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI);
+    int LROffset = Subtarget.getFrameLowering()->getReturnSaveOffset();
     // Allocate the frame index for frame pointer save area.
     RASI = MF.getFrameInfo()->CreateFixedObject(isPPC64? 8 : 4, LROffset, false);
     // Save the result.
@@ -9699,14 +9700,12 @@ SDValue PPCTargetLowering::LowerRETURNADDR(SDValue Op,
   PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
   FuncInfo->setLRStoreRequired();
   bool isPPC64 = Subtarget.isPPC64();
-  bool isDarwinABI = Subtarget.isDarwinABI();
 
   if (Depth > 0) {
     SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
     SDValue Offset =
-
-      DAG.getConstant(PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI),
-                      isPPC64? MVT::i64 : MVT::i32);
+        DAG.getConstant(Subtarget.getFrameLowering()->getReturnSaveOffset(),
+                        isPPC64 ? MVT::i64 : MVT::i32);
     return DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
                        DAG.getNode(ISD::ADD, dl, getPointerTy(),
                                    FrameAddr, Offset),
-- 
2.34.1