[PowerPC][Future] Add missing changes for PC Relative addressing features

[NeHuang]

Summary

• Use Subtarget.isUsingPCRelativeCalls() in functionPPCTargetLowering::LowerConstantPool to check if using PCRelative addressing.
• Change MO_GOT_FLAG = 32 to MO_GOT_FLAG = 8 in PPC.h to use consecutive bits.

[nemanjai]

LGTM.

llvm/lib/Target/PowerPC/PPC.h

enum TOF {
 
     /// MO_PCREL_FLAG - If this bit is set, the symbol reference is relative to
     /// the current instruction address(pc), e.g., var@pcrel. Fixup is VK_PCREL.
     MO_PCREL_FLAG = 4,
 
     /// MO_GOT_FLAG - If this bit is set the symbol reference is to be computed
     /// via the GOT. For example when combined with the MO_PCREL_FLAG it should
     /// produce the relocation @got@pcrel. Fixup is VK_PPC_GOT_PCREL.
-    MO_GOT_FLAG = 32,
+    MO_GOT_FLAG = 8,
 
     /// The next are not flags but distinct values.
     MO_ACCESS_MASK = 0xf00,
 
     /// MO_LO, MO_HA - lo16(symbol) and ha16(symbol)
     MO_LO = 1 << 8,
     MO_HA = 2 << 8,
 

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

SDValue PPCTargetLowering::LowerConstantPool(SDValue Op,
                                              SelectionDAG &DAG) const {
   EVT PtrVT = Op.getValueType();
   ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
   const Constant *C = CP->getConstVal();
 
   // 64-bit SVR4 ABI and AIX ABI code are always position-independent.
   // The actual address of the GlobalValue is stored in the TOC.
   if (Subtarget.is64BitELFABI() || Subtarget.isAIXABI()) {
-    if (Subtarget.hasPCRelativeMemops()) {
+    if (Subtarget.isUsingPCRelativeCalls()) {
       SDLoc DL(CP);
       EVT Ty = getPointerTy(DAG.getDataLayout());
       SDValue ConstPool = DAG.getTargetConstantPool(C, Ty,
                                                     CP->getAlignment(),
                                                     CP->getOffset(),
                                                     PPCII::MO_PCREL_FLAG);
       return DAG.getNode(PPCISD::MAT_PCREL_ADDR, DL, Ty, ConstPool);
     }