From f49fde28772cf73502d31e2755b7c75c0e90a05c Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanak@gmail.com>
Date: Mon, 4 Apr 2011 17:11:07 +0000
Subject: [PATCH] Move transformation of JmpLink and related nodes done during
 instruction selection to Legalize phase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128830 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/Mips/MipsISelDAGToDAG.cpp | 58 +---------------------------
 lib/Target/Mips/MipsISelLowering.cpp | 28 ++++++++++++--
 2 files changed, 27 insertions(+), 59 deletions(-)

diff --git a/lib/Target/Mips/MipsISelDAGToDAG.cpp b/lib/Target/Mips/MipsISelDAGToDAG.cpp
index 3749009112e..0382964fe94 100644
--- a/lib/Target/Mips/MipsISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsISelDAGToDAG.cpp
@@ -122,7 +122,8 @@ SelectAddr(SDValue Addr, SDValue &Offset, SDValue &Base) {
     if ((Addr.getOpcode() == ISD::TargetGlobalAddress) ||
         (Addr.getOpcode() == ISD::TargetConstantPool) ||
         (Addr.getOpcode() == ISD::TargetJumpTable) ||
-        (Addr.getOpcode() == ISD::TargetBlockAddress)) {
+        (Addr.getOpcode() == ISD::TargetBlockAddress) ||
+        (Addr.getOpcode() == ISD::TargetExternalSymbol)) {
       Base   = CurDAG->getRegister(Mips::GP, MVT::i32);
       Offset = Addr;
       return true;
@@ -444,61 +445,6 @@ SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
         return ResNode;
       // Other cases are autogenerated.
       break;
-
-    /// Handle direct and indirect calls when using PIC. On PIC, when
-    /// GOT is smaller than about 64k (small code) the GA target is
-    /// loaded with only one instruction. Otherwise GA's target must
-    /// be loaded with 3 instructions.
-    case MipsISD::JmpLink: {
-      if (TM.getRelocationModel() == Reloc::PIC_) {
-        unsigned LastOpNum = Node->getNumOperands()-1;
-
-        SDValue Chain  = Node->getOperand(0);
-        SDValue Callee = Node->getOperand(1);
-        SDValue InFlag;
-
-        // Skip the incomming flag if present
-        if (Node->getOperand(LastOpNum).getValueType() == MVT::Glue)
-          LastOpNum--;
-
-        if ( (isa<GlobalAddressSDNode>(Callee)) ||
-             (isa<ExternalSymbolSDNode>(Callee)) )
-        {
-          /// Direct call for global addresses and external symbols
-          SDValue GPReg = CurDAG->getRegister(Mips::GP, MVT::i32);
-
-          // Use load to get GOT target
-          SDValue Ops[] = { Callee, GPReg, Chain };
-          SDValue Load = SDValue(CurDAG->getMachineNode(Mips::LW, dl, MVT::i32,
-                                     MVT::Other, Ops, 3), 0);
-          Chain = Load.getValue(1);
-
-          // Call target must be on T9
-          Chain = CurDAG->getCopyToReg(Chain, dl, Mips::T9, Load, InFlag);
-        } else
-          /// Indirect call
-          Chain = CurDAG->getCopyToReg(Chain, dl, Mips::T9, Callee, InFlag);
-
-        // Map the JmpLink operands to JALR
-        SDVTList NodeTys = CurDAG->getVTList(MVT::Other, MVT::Glue);
-        SmallVector<SDValue, 8> Ops;
-        Ops.push_back(CurDAG->getRegister(Mips::T9, MVT::i32));
-
-        for (unsigned i = 2, e = LastOpNum+1; i != e; ++i)
-          Ops.push_back(Node->getOperand(i));
-        Ops.push_back(Chain);
-        Ops.push_back(Chain.getValue(1));
-
-        // Emit Jump and Link Register
-        SDNode *ResNode = CurDAG->getMachineNode(Mips::JALR, dl, NodeTys,
-                                  &Ops[0], Ops.size());
-
-        // Replace Chain and InFlag
-        ReplaceUses(SDValue(Node, 0), SDValue(ResNode, 0));
-        ReplaceUses(SDValue(Node, 1), SDValue(ResNode, 1));
-        return ResNode;
-      }
-    }
   }
 
   // Select the default instruction
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 59ad81b5a7e..20df9c86327 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -1201,12 +1201,34 @@ MipsTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
   // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
   // node so that legalize doesn't hack it.
   unsigned char OpFlag = IsPIC ? MipsII::MO_GOT_CALL : MipsII::MO_NO_FLAG;
-  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+  bool LoadSymAddr = false;
+
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
     Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl,
-                                getPointerTy(), 0, OpFlag);
-  else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee))
+                                        getPointerTy(), 0, OpFlag);
+    LoadSymAddr = true;
+  }
+  else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
     Callee = DAG.getTargetExternalSymbol(S->getSymbol(),
                                 getPointerTy(), OpFlag);
+    LoadSymAddr = true;
+  }
+
+  // Create nodes that load address of callee and copy it to T9
+  if (IsPIC) {
+    if (LoadSymAddr) {
+      // load callee address
+      Callee = DAG.getLoad(MVT::i32, dl, Chain, Callee,
+                           MachinePointerInfo::getGOT(),
+                           false, false, 0);
+      Chain = Callee.getValue(1);
+    }
+
+    // copy to T9
+    Chain = DAG.getCopyToReg(Chain, dl, Mips::T9, Callee, SDValue(0, 0));
+    InFlag = Chain.getValue(1);
+    Callee = DAG.getRegister(Mips::T9, MVT::i32);
+  }
 
   // MipsJmpLink = #chain, #target_address, #opt_in_flags...
   //             = Chain, Callee, Reg#1, Reg#2, ...
-- 
2.34.1