reimplement elf TLS support in terms of addressing modes, eliminating SegmentBaseAddress.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114529 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 43 insertions, 59 deletions

diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index a22d3edb4c..b3e409f0ea 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -190,8 +190,7 @@ namespace {
     SDNode *SelectAtomic64(SDNode *Node, unsigned Opc);
     SDNode *SelectAtomicLoadAdd(SDNode *Node, EVT NVT);
 
-    bool MatchSegmentBaseAddress(SDValue N, X86ISelAddressMode &AM);
-    bool MatchLoad(SDValue N, X86ISelAddressMode &AM);
+    bool MatchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM);
     bool MatchWrapper(SDValue N, X86ISelAddressMode &AM);
     bool MatchAddress(SDValue N, X86ISelAddressMode &AM);
     bool MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
@@ -544,29 +543,27 @@ void X86DAGToDAGISel::EmitFunctionEntryCode() {
 }
 
 
-bool X86DAGToDAGISel::MatchSegmentBaseAddress(SDValue N,
-                                              X86ISelAddressMode &AM) {
-  assert(N.getOpcode() == X86ISD::SegmentBaseAddress);
-  SDValue Segment = N.getOperand(0);
-
-  if (AM.Segment.getNode() == 0) {
-    AM.Segment = Segment;
-    return false;
-  }
-
-  return true;
-}
-
-bool X86DAGToDAGISel::MatchLoad(SDValue N, X86ISelAddressMode &AM) {
+bool X86DAGToDAGISel::MatchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM){
+  SDValue Address = N->getOperand(1);
+  
+  // load gs:0 -> GS segment register.
+  // load fs:0 -> FS segment register.
+  //
   // This optimization is valid because the GNU TLS model defines that
   // gs:0 (or fs:0 on X86-64) contains its own address.
   // For more information see http://people.redhat.com/drepper/tls.pdf
-
-  SDValue Address = N.getOperand(1);
-  if (Address.getOpcode() == X86ISD::SegmentBaseAddress &&
-      !MatchSegmentBaseAddress(Address, AM))
-    return false;
-
+  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Address))
+    if (C->getSExtValue() == 0 && AM.Segment.getNode() == 0 &&
+        Subtarget->isTargetELF())
+      switch (N->getPointerInfo().getAddrSpace()) {
+      case 256:
+        AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
+        return false;
+      case 257:
+        AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
+        return false;
+      }
+  
   return true;
 }
 
@@ -751,11 +748,6 @@ bool X86DAGToDAGISel::MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
     break;
   }
 
-  case X86ISD::SegmentBaseAddress:
-    if (!MatchSegmentBaseAddress(N, AM))
-      return false;
-    break;
-
   case X86ISD::Wrapper:
   case X86ISD::WrapperRIP:
     if (!MatchWrapper(N, AM))
@@ -763,7 +755,7 @@ bool X86DAGToDAGISel::MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
     break;
 
   case ISD::LOAD:
-    if (!MatchLoad(N, AM))
+    if (!MatchLoadInAddress(cast<LoadSDNode>(N), AM))
       return false;
     break;
 
@@ -1151,18 +1143,7 @@ bool X86DAGToDAGISel::SelectAddr(SDNode *Parent, SDValue N, SDValue &Base,
                                  SDValue &Scale, SDValue &Index,
                                  SDValue &Disp, SDValue &Segment) {
   X86ISelAddressMode AM;
-  if (MatchAddress(N, AM))
-    return false;
-
-  EVT VT = N.getValueType();
-  if (AM.BaseType == X86ISelAddressMode::RegBase) {
-    if (!AM.Base_Reg.getNode())
-      AM.Base_Reg = CurDAG->getRegister(0, VT);
-  }
-
-  if (!AM.IndexReg.getNode())
-    AM.IndexReg = CurDAG->getRegister(0, VT);
-
+  
   if (Parent &&
       // This list of opcodes are all the nodes that have an "addr:$ptr" operand
       // that are not a MemSDNode, and thus don't have proper addrspace info.
@@ -1173,12 +1154,23 @@ bool X86DAGToDAGISel::SelectAddr(SDNode *Parent, SDValue N, SDValue &Base,
       cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
     // AddrSpace 256 -> GS, 257 -> FS.
     if (AddrSpace == 256)
-      AM.Segment = CurDAG->getRegister(X86::GS, VT);
+      AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
     if (AddrSpace == 257)
-      AM.Segment = CurDAG->getRegister(X86::FS, VT);
+      AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
   }
   
-  
+  if (MatchAddress(N, AM))
+    return false;
+
+  EVT VT = N.getValueType();
+  if (AM.BaseType == X86ISelAddressMode::RegBase) {
+    if (!AM.Base_Reg.getNode())
+      AM.Base_Reg = CurDAG->getRegister(0, VT);
+  }
+
+  if (!AM.IndexReg.getNode())
+    AM.IndexReg = CurDAG->getRegister(0, VT);
+
   getAddressOperands(AM, Base, Scale, Index, Disp, Segment);
   return true;
 }
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index e896b8c401..7e08558591 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6150,14 +6150,14 @@ static SDValue LowerToTLSExecModel(GlobalAddressSDNode *GA, SelectionDAG &DAG,
                                    const EVT PtrVT, TLSModel::Model model,
                                    bool is64Bit) {
   DebugLoc dl = GA->getDebugLoc();
-  // Get the Thread Pointer
-  SDValue Base = DAG.getNode(X86ISD::SegmentBaseAddress,
-                             DebugLoc(), PtrVT,
-                             DAG.getRegister(is64Bit? X86::FS : X86::GS,
-                                             MVT::i32));
+  
+  // Get the Thread Pointer, which is %gs:0 (32-bit) or %fs:0 (64-bit).
+  Value *Ptr = Constant::getNullValue(Type::getInt8PtrTy(*DAG.getContext(),
+                                                         is64Bit ? 257 : 256));
 
-  SDValue ThreadPointer = DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), Base,
-                                      MachinePointerInfo(), false, false, 0);
+  SDValue ThreadPointer = DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), 
+                                      DAG.getIntPtrConstant(0),
+                                      MachinePointerInfo(Ptr), false, false, 0);
 
   unsigned char OperandFlags = 0;
   // Most TLS accesses are not RIP relative, even on x86-64.  One exception is
@@ -8845,7 +8845,6 @@ const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
   case X86ISD::FRCP:               return "X86ISD::FRCP";
   case X86ISD::TLSADDR:            return "X86ISD::TLSADDR";
   case X86ISD::TLSCALL:            return "X86ISD::TLSCALL";
-  case X86ISD::SegmentBaseAddress: return "X86ISD::SegmentBaseAddress";
   case X86ISD::EH_RETURN:          return "X86ISD::EH_RETURN";
   case X86ISD::TC_RETURN:          return "X86ISD::TC_RETURN";
   case X86ISD::FNSTCW16m:          return "X86ISD::FNSTCW16m";
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index e856206d73..2a86fa8c70 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -172,9 +172,6 @@ namespace llvm {
       // thunk at the address from an earlier relocation.
       TLSCALL,
 
-      // SegmentBaseAddress - The address segment:0
-      SegmentBaseAddress,
-
       // EH_RETURN - Exception Handling helpers.
       EH_RETURN,
       
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index bf8eb1b7c9..fa1b8bac52 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -74,8 +74,6 @@ def SDT_X86TLSADDR : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 def SDT_X86TLSCALL : SDTypeProfile<0, 1, [SDTCisPtrTy<0>]>;
 
-def SDT_X86SegmentBaseAddress : SDTypeProfile<1, 1, [SDTCisPtrTy<0>]>;
-
 def SDT_X86EHRET : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 def SDT_X86TCRET : SDTypeProfile<0, 2, [SDTCisPtrTy<0>, SDTCisVT<1, i32>]>;
@@ -169,8 +167,6 @@ def X86WrapperRIP : SDNode<"X86ISD::WrapperRIP",  SDTX86Wrapper>;
 
 def X86tlsaddr : SDNode<"X86ISD::TLSADDR", SDT_X86TLSADDR,
                         [SDNPHasChain, SDNPOptInFlag, SDNPOutFlag]>;
-def X86SegmentBaseAddress : SDNode<"X86ISD::SegmentBaseAddress",
-                                 SDT_X86SegmentBaseAddress, []>;
 
 def X86ehret : SDNode<"X86ISD::EH_RETURN", SDT_X86EHRET,
                         [SDNPHasChain]>;
diff --git a/test/CodeGen/X86/tls9.ll b/test/CodeGen/X86/tls9.ll
index 214146fe99..7d08df84a9 100644
--- a/test/CodeGen/X86/tls9.ll
+++ b/test/CodeGen/X86/tls9.ll
@@ -5,7 +5,7 @@
 
 @i = external hidden thread_local global i32
 
-define i32 @f() {
+define i32 @f() nounwind {
 entry:
 	%tmp1 = load i32* @i
 	ret i32 %tmp1