Materialize GA addresses with movw + movt pairs for Darwin in PIC mode. e.g.
        movw    r0, :lower16:(L_foo$non_lazy_ptr-(LPC0_0+4))
        movt    r0, :upper16:(L_foo$non_lazy_ptr-(LPC0_0+4))
LPC0_0:
        add     r0, pc, r0

It's not yet enabled by default as some tests are failing. I suspect bugs in
down stream tools.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123619 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 0167bd7..3710be2 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -734,6 +734,7 @@
   switch (Opcode) {
   default: return 0;
   case ARMISD::Wrapper:       return "ARMISD::Wrapper";
+  case ARMISD::WrapperPIC:    return "ARMISD::WrapperPIC";
   case ARMISD::WrapperJT:     return "ARMISD::WrapperJT";
   case ARMISD::CALL:          return "ARMISD::CALL";
   case ARMISD::CALL_PRED:     return "ARMISD::CALL_PRED";
@@ -1315,7 +1316,7 @@
     if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
       const GlobalValue *GV = G->getGlobal();
       // Create a constant pool entry for the callee address
-      unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+      unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
       ARMConstantPoolValue *CPV = new ARMConstantPoolValue(GV,
                                                            ARMPCLabelIndex,
                                                            ARMCP::CPValue, 0);
@@ -1330,7 +1331,7 @@
       const char *Sym = S->getSymbol();
 
       // Create a constant pool entry for the callee address
-      unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+      unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
       ARMConstantPoolValue *CPV = new ARMConstantPoolValue(*DAG.getContext(),
                                                        Sym, ARMPCLabelIndex, 0);
       // Get the address of the callee into a register
@@ -1352,7 +1353,7 @@
     isLocalARMFunc = !Subtarget->isThumb() && (!isExt || !ARMInterworking);
     // tBX takes a register source operand.
     if (isARMFunc && Subtarget->isThumb1Only() && !Subtarget->hasV5TOps()) {
-      unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+      unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
       ARMConstantPoolValue *CPV = new ARMConstantPoolValue(GV,
                                                            ARMPCLabelIndex,
                                                            ARMCP::CPValue, 4);
@@ -1381,7 +1382,7 @@
     // tBX takes a register source operand.
     const char *Sym = S->getSymbol();
     if (isARMFunc && Subtarget->isThumb1Only() && !Subtarget->hasV5TOps()) {
-      unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+      unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
       ARMConstantPoolValue *CPV = new ARMConstantPoolValue(*DAG.getContext(),
                                                        Sym, ARMPCLabelIndex, 4);
       SDValue CPAddr = DAG.getTargetConstantPool(CPV, getPointerTy(), 4);
@@ -1808,7 +1809,7 @@
     CPAddr = DAG.getTargetConstantPool(BA, PtrVT, 4);
   } else {
     unsigned PCAdj = Subtarget->isThumb() ? 4 : 8;
-    ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+    ARMPCLabelIndex = AFI->createPICLabelUId();
     ARMConstantPoolValue *CPV = new ARMConstantPoolValue(BA, ARMPCLabelIndex,
                                                          ARMCP::CPBlockAddress,
                                                          PCAdj);
@@ -1833,7 +1834,7 @@
   unsigned char PCAdj = Subtarget->isThumb() ? 4 : 8;
   MachineFunction &MF = DAG.getMachineFunction();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+  unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
   ARMConstantPoolValue *CPV =
     new ARMConstantPoolValue(GA->getGlobal(), ARMPCLabelIndex,
                              ARMCP::CPValue, PCAdj, ARMCP::TLSGD, true);
@@ -1878,7 +1879,7 @@
   if (GV->isDeclaration()) {
     MachineFunction &MF = DAG.getMachineFunction();
     ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-    unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+    unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
     // Initial exec model.
     unsigned char PCAdj = Subtarget->isThumb() ? 4 : 8;
     ARMConstantPoolValue *CPV =
@@ -1949,36 +1950,55 @@
       Result = DAG.getLoad(PtrVT, dl, Chain, Result,
                            MachinePointerInfo::getGOT(), false, false, 0);
     return Result;
+  }
+
+  // If we have T2 ops, we can materialize the address directly via movt/movw
+  // pair. This is always cheaper.
+  if (Subtarget->useMovt()) {
+    // FIXME: Once remat is capable of dealing with instructions with register
+    // operands, expand this into two nodes.
+    return DAG.getNode(ARMISD::Wrapper, dl, PtrVT,
+                       DAG.getTargetGlobalAddress(GV, dl, PtrVT));
   } else {
-    // If we have T2 ops, we can materialize the address directly via movt/movw
-    // pair. This is always cheaper.
-    if (Subtarget->useMovt()) {
-      return DAG.getNode(ARMISD::Wrapper, dl, PtrVT,
-                         DAG.getTargetGlobalAddress(GV, dl, PtrVT));
-    } else {
-      SDValue CPAddr = DAG.getTargetConstantPool(GV, PtrVT, 4);
-      CPAddr = DAG.getNode(ARMISD::Wrapper, dl, MVT::i32, CPAddr);
-      return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), CPAddr,
-                         MachinePointerInfo::getConstantPool(),
-                         false, false, 0);
-    }
+    SDValue CPAddr = DAG.getTargetConstantPool(GV, PtrVT, 4);
+    CPAddr = DAG.getNode(ARMISD::Wrapper, dl, MVT::i32, CPAddr);
+    return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), CPAddr,
+                       MachinePointerInfo::getConstantPool(),
+                       false, false, 0);
   }
 }
 
 SDValue ARMTargetLowering::LowerGlobalAddressDarwin(SDValue Op,
                                                     SelectionDAG &DAG) const {
-  MachineFunction &MF = DAG.getMachineFunction();
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  unsigned ARMPCLabelIndex = 0;
   EVT PtrVT = getPointerTy();
   DebugLoc dl = Op.getDebugLoc();
   const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
   Reloc::Model RelocM = getTargetMachine().getRelocationModel();
+  MachineFunction &MF = DAG.getMachineFunction();
+  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+
+  if (Subtarget->useMovt()) {
+    // FIXME: Once remat is capable of dealing with instructions with register
+    // operands, expand this into two nodes.
+    if (RelocM != Reloc::PIC_)
+      return DAG.getNode(ARMISD::Wrapper, dl, PtrVT,
+                                 DAG.getTargetGlobalAddress(GV, dl, PtrVT));
+
+    // FIXME: Not a constant pool!
+    unsigned PICLabelIndex = AFI->createPICLabelUId();
+    SDValue PICLabel = DAG.getConstant(PICLabelIndex, MVT::i32);
+    SDValue Result = DAG.getNode(ARMISD::WrapperPIC, dl, PtrVT,
+                                 DAG.getTargetGlobalAddress(GV, dl, PtrVT),
+                                 PICLabel);
+    return DAG.getNode(ARMISD::PIC_ADD, dl, PtrVT, Result, PICLabel);    
+  }
+
+  unsigned ARMPCLabelIndex = 0;
   SDValue CPAddr;
-  if (RelocM == Reloc::Static)
+  if (RelocM == Reloc::Static) {
     CPAddr = DAG.getTargetConstantPool(GV, PtrVT, 4);
-  else {
-    ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+  } else {
+    ARMPCLabelIndex = AFI->createPICLabelUId();
     unsigned PCAdj = (RelocM != Reloc::PIC_) ? 0 : (Subtarget->isThumb()?4:8);
     ARMConstantPoolValue *CPV =
       new ARMConstantPoolValue(GV, ARMPCLabelIndex, ARMCP::CPValue, PCAdj);
@@ -2009,7 +2029,7 @@
          "GLOBAL OFFSET TABLE not implemented for non-ELF targets");
   MachineFunction &MF = DAG.getMachineFunction();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+  unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
   EVT PtrVT = getPointerTy();
   DebugLoc dl = Op.getDebugLoc();
   unsigned PCAdj = Subtarget->isThumb() ? 4 : 8;
@@ -2062,7 +2082,7 @@
   case Intrinsic::eh_sjlj_lsda: {
     MachineFunction &MF = DAG.getMachineFunction();
     ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-    unsigned ARMPCLabelIndex = AFI->createConstPoolEntryUId();
+    unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
     EVT PtrVT = getPointerTy();
     DebugLoc dl = Op.getDebugLoc();
     Reloc::Model RelocM = getTargetMachine().getRelocationModel();