ARM: support TLS for WoA

Add support for TLS access for Windows on ARM.  This generates a similar access
to MSVC for ARM.

The changes to the tablegen data is needed to support loading an external symbol
global that is not for a call.  The adjustments to the DAG to DAG transforms are
needed to preserve the 32-bit move.

llvm-svn: 259676

5 files changed, 62 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 89e0bab3d0b..afeee047048 100644
--- a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -623,6 +623,7 @@ bool ARMDAGToDAGISel::SelectAddrModeImm12(SDValue N,
 
     if (N.getOpcode() == ARMISD::Wrapper &&
         N.getOperand(0).getOpcode() != ISD::TargetGlobalAddress &&
+        N.getOperand(0).getOpcode() != ISD::TargetExternalSymbol &&
         N.getOperand(0).getOpcode() != ISD::TargetGlobalTLSAddress) {
       Base = N.getOperand(0);
     } else
@@ -803,6 +804,7 @@ AddrMode2Type ARMDAGToDAGISel::SelectAddrMode2Worker(SDValue N,
           FI, TLI->getPointerTy(CurDAG->getDataLayout()));
     } else if (N.getOpcode() == ARMISD::Wrapper &&
                N.getOperand(0).getOpcode() != ISD::TargetGlobalAddress &&
+               N.getOperand(0).getOpcode() != ISD::TargetExternalSymbol &&
                N.getOperand(0).getOpcode() != ISD::TargetGlobalTLSAddress) {
       Base = N.getOperand(0);
     }
@@ -1070,6 +1072,7 @@ bool ARMDAGToDAGISel::SelectAddrMode5(SDValue N,
           FI, TLI->getPointerTy(CurDAG->getDataLayout()));
     } else if (N.getOpcode() == ARMISD::Wrapper &&
                N.getOperand(0).getOpcode() != ISD::TargetGlobalAddress &&
+               N.getOperand(0).getOpcode() != ISD::TargetExternalSymbol &&
                N.getOperand(0).getOpcode() != ISD::TargetGlobalTLSAddress) {
       Base = N.getOperand(0);
     }
@@ -1190,6 +1193,7 @@ ARMDAGToDAGISel::SelectThumbAddrModeImm5S(SDValue N, unsigned Scale,
       return false; // We want to select register offset instead
     } else if (N.getOpcode() == ARMISD::Wrapper &&
         N.getOperand(0).getOpcode() != ISD::TargetGlobalAddress &&
+        N.getOperand(0).getOpcode() != ISD::TargetExternalSymbol &&
         N.getOperand(0).getOpcode() != ISD::TargetGlobalTLSAddress) {
       Base = N.getOperand(0);
     } else {
@@ -1297,6 +1301,7 @@ bool ARMDAGToDAGISel::SelectT2AddrModeImm12(SDValue N,
 
     if (N.getOpcode() == ARMISD::Wrapper &&
         N.getOperand(0).getOpcode() != ISD::TargetGlobalAddress &&
+        N.getOperand(0).getOpcode() != ISD::TargetExternalSymbol &&
         N.getOperand(0).getOpcode() != ISD::TargetGlobalTLSAddress) {
       Base = N.getOperand(0);
       if (Base.getOpcode() == ISD::TargetConstantPool)
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 496358ea609..228b18bbbd4 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -2613,6 +2613,55 @@ ARMTargetLowering::LowerGlobalTLSAddressDarwin(SDValue Op,
   return DAG.getCopyFromReg(Chain, DL, ARM::R0, MVT::i32, Chain.getValue(1));
 }
 
+SDValue
+ARMTargetLowering::LowerGlobalTLSAddressWindows(SDValue Op,
+                                                SelectionDAG &DAG) const {
+  assert(Subtarget->isTargetWindows() && "Windows specific TLS lowering");
+  SDValue Chain = DAG.getEntryNode();
+  EVT PtrVT = getPointerTy(DAG.getDataLayout());
+  SDLoc DL(Op);
+
+  // Load the current TEB (thread environment block)
+  SDValue Ops[] = {Chain,
+                   DAG.getConstant(Intrinsic::arm_mrc, DL, MVT::i32),
+                   DAG.getConstant(15, DL, MVT::i32),
+                   DAG.getConstant(0, DL, MVT::i32),
+                   DAG.getConstant(13, DL, MVT::i32),
+                   DAG.getConstant(0, DL, MVT::i32),
+                   DAG.getConstant(2, DL, MVT::i32)};
+  SDValue CurrentTEB = DAG.getNode(ISD::INTRINSIC_W_CHAIN, DL,
+                                   DAG.getVTList(MVT::i32, MVT::Other), Ops);
+
+  SDValue TEB = CurrentTEB.getValue(0);
+  Chain = CurrentTEB.getValue(1);
+
+  // Load the ThreadLocalStoragePointer from the TEB
+  // A pointer to the TLS array is located at offset 0x2c from the TEB.
+  SDValue TLSArray =
+      DAG.getNode(ISD::ADD, DL, PtrVT, TEB, DAG.getIntPtrConstant(0x2c, DL));
+  TLSArray = DAG.getLoad(PtrVT, DL, Chain, TLSArray, MachinePointerInfo(),
+                         false, false, false, 0);
+
+  // The pointer to the thread's TLS data area is at the TLS Index scaled by 4
+  // offset into the TLSArray.
+
+  // Load the TLS index from the C runtime
+  SDValue TLSIndex =
+      DAG.getTargetExternalSymbol("_tls_index", PtrVT, ARMII::MO_NO_FLAG);
+  TLSIndex = DAG.getNode(ARMISD::Wrapper, DL, PtrVT, TLSIndex);
+  TLSIndex = DAG.getLoad(PtrVT, DL, Chain, TLSIndex, MachinePointerInfo(),
+                         false, false, false, 0);
+
+  SDValue Slot = DAG.getNode(ISD::SHL, DL, PtrVT, TLSIndex,
+                              DAG.getConstant(2, DL, MVT::i32));
+  SDValue TLS = DAG.getLoad(PtrVT, DL, Chain,
+                            DAG.getNode(ISD::ADD, DL, PtrVT, TLSArray, Slot),
+                            MachinePointerInfo(), false, false, false, 0);
+
+  return DAG.getNode(ISD::ADD, DL, PtrVT, TLS,
+                     LowerGlobalAddressWindows(Op, DAG));
+}
+
 // Lower ISD::GlobalTLSAddress using the "general dynamic" model
 SDValue
 ARMTargetLowering::LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
@@ -2717,6 +2766,9 @@ ARMTargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
   if (Subtarget->isTargetDarwin())
     return LowerGlobalTLSAddressDarwin(Op, DAG);
 
+  if (Subtarget->isTargetWindows())
+    return LowerGlobalTLSAddressWindows(Op, DAG);
+
   // TODO: implement the "local dynamic" model
   assert(Subtarget->isTargetELF() && "Only ELF implemented here");
   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index 96b56c3ec33..a502ca12fa8 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -527,6 +527,7 @@ namespace llvm {
                                  SelectionDAG &DAG,
                                  TLSModel::Model model) const;
     SDValue LowerGlobalTLSAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerGlobalTLSAddressWindows(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGLOBAL_OFFSET_TABLE(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerXALUO(SDValue Op, SelectionDAG &DAG) const;
diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td
index 776e53bc459..32513e90043 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.td
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.td
@@ -5453,6 +5453,8 @@ def : Pat<(load (ARMWrapperPIC tglobaltlsaddr:$addr)),
 def : ARMPat<(ARMWrapper  tconstpool  :$dst), (LEApcrel tconstpool  :$dst)>;
 def : ARMPat<(ARMWrapper  tglobaladdr :$dst), (MOVi32imm tglobaladdr :$dst)>,
             Requires<[IsARM, UseMovt]>;
+def : ARMPat<(ARMWrapper texternalsym :$dst), (MOVi32imm texternalsym :$dst)>,
+            Requires<[IsARM, UseMovt]>;
 def : ARMPat<(ARMWrapperJT tjumptable:$dst),
              (LEApcrelJT tjumptable:$dst)>;
 
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index a63bf9abcdf..48c72beb73f 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -3906,6 +3906,8 @@ def : T2Pat<(ARMWrapper tglobaltlsaddr:$dst),
 
 // ConstantPool, GlobalAddress, and JumpTable
 def : T2Pat<(ARMWrapper  tconstpool  :$dst), (t2LEApcrel tconstpool  :$dst)>;
+def : T2Pat<(ARMWrapper texternalsym :$dst), (t2MOVi32imm texternalsym : $dst)>,
+          Requires<[IsThumb, HasV8MBaseline, UseMovt]>;
 def : T2Pat<(ARMWrapper  tglobaladdr :$dst), (t2MOVi32imm tglobaladdr :$dst)>,
            Requires<[IsThumb, HasV8MBaseline, UseMovt]>;