Reland [NFCI] Refactor X86TargetLowering::getGlobalWrapperKind()

To simplify D150297.

We should be looking at OpFlags more.

Relanding after fix in https://reviews.llvm.org/D159297, hopefully now this is actually NFC.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D157907

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -18183,15 +18183,17 @@ unsigned X86TargetLowering::getGlobalWrapperKind(
   if (GV && GV->isAbsoluteSymbolRef())
     return X86ISD::Wrapper;
 
-  CodeModel::Model M = getTargetMachine().getCodeModel();
+  // The following OpFlags under RIP-rel PIC use RIP.
   if (Subtarget.isPICStyleRIPRel() &&
-      (M == CodeModel::Small || M == CodeModel::Kernel))
+      (OpFlags == X86II::MO_NO_FLAG || OpFlags == X86II::MO_COFFSTUB ||
+       OpFlags == X86II::MO_DLLIMPORT))
     return X86ISD::WrapperRIP;
 
   // In the medium model, functions can always be referenced RIP-relatively,
   // since they must be within 2GiB. This is also possible in non-PIC mode, and
   // shorter than the 64-bit absolute immediate that would otherwise be emitted.
-  if (M == CodeModel::Medium && isa_and_nonnull<Function>(GV))
+  if (getTargetMachine().getCodeModel() == CodeModel::Medium &&
+      isa_and_nonnull<Function>(GV))
     return X86ISD::WrapperRIP;
 
   // GOTPCREL references must always use RIP.
@@ -18219,7 +18221,8 @@ X86TargetLowering::LowerConstantPool(SDValue Op, SelectionDAG &DAG) const {
   SDValue Result = DAG.getTargetConstantPool(
       CP->getConstVal(), PtrVT, CP->getAlign(), CP->getOffset(), OpFlag);
   SDLoc DL(CP);
-  Result = DAG.getNode(getGlobalWrapperKind(), DL, PtrVT, Result);
+  Result =
+      DAG.getNode(getGlobalWrapperKind(nullptr, OpFlag), DL, PtrVT, Result);
   // With PIC, the address is actually $g + Offset.
   if (OpFlag) {
     Result =
@@ -18240,7 +18243,8 @@ SDValue X86TargetLowering::LowerJumpTable(SDValue Op, SelectionDAG &DAG) const {
   auto PtrVT = getPointerTy(DAG.getDataLayout());
   SDValue Result = DAG.getTargetJumpTable(JT->getIndex(), PtrVT, OpFlag);
   SDLoc DL(JT);
-  Result = DAG.getNode(getGlobalWrapperKind(), DL, PtrVT, Result);
+  Result =
+      DAG.getNode(getGlobalWrapperKind(nullptr, OpFlag), DL, PtrVT, Result);
 
   // With PIC, the address is actually $g + Offset.
   if (OpFlag)
@@ -18266,7 +18270,8 @@ X86TargetLowering::LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const {
   SDLoc dl(Op);
   auto PtrVT = getPointerTy(DAG.getDataLayout());
   SDValue Result = DAG.getTargetBlockAddress(BA, PtrVT, Offset, OpFlags);
-  Result = DAG.getNode(getGlobalWrapperKind(), dl, PtrVT, Result);
+  Result =
+      DAG.getNode(getGlobalWrapperKind(nullptr, OpFlags), dl, PtrVT, Result);
 
   // With PIC, the address is actually $g + Offset.
   if (isGlobalRelativeToPICBase(OpFlags)) {
@@ -25982,7 +25987,7 @@ SDValue X86TargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
     auto &Context = MF.getMMI().getContext();
     MCSymbol *S = Context.getOrCreateSymbol(Twine("GCC_except_table") +
                                             Twine(MF.getFunctionNumber()));
-    return DAG.getNode(getGlobalWrapperKind(), dl, VT,
+    return DAG.getNode(getGlobalWrapperKind(nullptr, /*OpFlags=*/0), dl, VT,
                        DAG.getMCSymbol(S, PtrVT));
   }
 

llvm/lib/Target/X86/X86ISelLowering.h

@@ -1636,8 +1636,8 @@ namespace llvm {
     SDValue LowerEXTRACT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
 
-    unsigned getGlobalWrapperKind(const GlobalValue *GV = nullptr,
-                                  const unsigned char OpFlags = 0) const;
+    unsigned getGlobalWrapperKind(const GlobalValue *GV,
+                                  const unsigned char OpFlags) const;
     SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;

llvm/lib/Target/X86/X86Subtarget.cpp

@@ -323,7 +323,9 @@ X86Subtarget::X86Subtarget(const Triple &TT, StringRef CPU, StringRef TuneCPU,
       InstrInfo(initializeSubtargetDependencies(CPU, TuneCPU, FS)),
       TLInfo(TM, *this), FrameLowering(*this, getStackAlignment()) {
   // Determine the PICStyle based on the target selected.
-  if (!isPositionIndependent())
+  if (!isPositionIndependent() || TM.getCodeModel() == CodeModel::Large)
+    // With the large code model, None forces all memory accesses to be indirect
+    // rather than RIP-relative.
     setPICStyle(PICStyles::Style::None);
   else if (is64Bit())
     setPICStyle(PICStyles::Style::RIPRel);