[mips] Make sure loads from lazy-binding entries do not get CSE'd or hoisted out

of loops.

Previously, two consecutive calls to function "func" would result in the
following sequence of instructions:

1. load $16, %got(func)($gp) // load address of lazy-binding stub.
2. move $25, $16
3. jalr $25                  // jump to lazy-binding stub.
4. nop
5. move $25, $16
6. jalr $25                  // jump to lazy-binding stub again.

With this patch, the second call directly jumps to func's address, bypassing
the lazy-binding resolution routine:

1. load $25, %got(func)($gp) // load address of lazy-binding stub.
2. jalr $25                  // jump to lazy-binding stub.
3. nop
4. load $25, %got(func)($gp) // load resolved address of func.
5. jalr $25                  // directly jump to func.

llvm-svn: 191591

4 files changed, 33 insertions, 19 deletions

diff --git a/llvm/lib/Target/Mips/Mips16ISelLowering.cpp b/llvm/lib/Target/Mips/Mips16ISelLowering.cpp
index 89f3d3ba175..ab649bd9882 100644
--- a/llvm/lib/Target/Mips/Mips16ISelLowering.cpp
+++ b/llvm/lib/Target/Mips/Mips16ISelLowering.cpp
@@ -419,6 +419,8 @@ getOpndList(SmallVectorImpl<SDValue> &Ops,
             bool IsPICCall, bool GlobalOrExternal, bool InternalLinkage,
             CallLoweringInfo &CLI, SDValue Callee, SDValue Chain) const {
   SelectionDAG &DAG = CLI.DAG;
+  MachineFunction &MF = DAG.getMachineFunction();
+  MipsFunctionInfo *FuncInfo = MF.getInfo<MipsFunctionInfo>();
   const char* Mips16HelperFunction = 0;
   bool NeedMips16Helper = false;
 
@@ -474,9 +476,10 @@ getOpndList(SmallVectorImpl<SDValue> &Ops,
     if (NeedMips16Helper) {
       RegsToPass.push_front(std::make_pair(V0Reg, Callee));
       JumpTarget = DAG.getExternalSymbol(Mips16HelperFunction, getPointerTy());
-      JumpTarget = getAddrGlobal(cast<ExternalSymbolSDNode>(JumpTarget),
-                                 JumpTarget.getValueType(), DAG,
-                                 MipsII::MO_GOT);
+      ExternalSymbolSDNode *S = cast<ExternalSymbolSDNode>(JumpTarget);
+      JumpTarget = getAddrGlobal(S, JumpTarget.getValueType(), DAG,
+                                 MipsII::MO_GOT, Chain,
+                                 FuncInfo->callPtrInfo(S->getSymbol()));
     } else
       RegsToPass.push_front(std::make_pair((unsigned)Mips::T9, Callee));
   }
diff --git a/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp b/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
index 545a38dba32..34286db16af 100644
--- a/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
+++ b/llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
@@ -421,8 +421,7 @@ bool LoadFromStackOrConst::hasHazard_(const MachineInstr &MI) {
     return false;
 
   if (const PseudoSourceValue *PSV = dyn_cast<const PseudoSourceValue>(V))
-    return !PSV->PseudoSourceValue::isConstant(0) &&
-      (V != PseudoSourceValue::getStack());
+    return !PSV->isConstant(0) && V != PseudoSourceValue::getStack();
 
   return true;
 }
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 5aab3f8dd2f..3eb2dfb6d67 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -1468,10 +1468,12 @@ SDValue MipsTargetLowering::lowerGlobalAddress(SDValue Op,
 
   if (LargeGOT)
     return getAddrGlobalLargeGOT(N, Ty, DAG, MipsII::MO_GOT_HI16,
-                                 MipsII::MO_GOT_LO16);
+                                 MipsII::MO_GOT_LO16, DAG.getEntryNode(),
+                                 MachinePointerInfo::getGOT());
 
   return getAddrGlobal(N, Ty, DAG,
-                       HasMips64 ? MipsII::MO_GOT_DISP : MipsII::MO_GOT16);
+                       HasMips64 ? MipsII::MO_GOT_DISP : MipsII::MO_GOT16,
+                       DAG.getEntryNode(), MachinePointerInfo::getGOT());
 }
 
 SDValue MipsTargetLowering::lowerBlockAddress(SDValue Op,
@@ -2313,6 +2315,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   MachineFunction &MF = DAG.getMachineFunction();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   const TargetFrameLowering *TFL = MF.getTarget().getFrameLowering();
+  MipsFunctionInfo *FuncInfo = MF.getInfo<MipsFunctionInfo>();
   bool IsPIC = getTargetMachine().getRelocationModel() == Reloc::PIC_;
 
   // Analyze operands of the call, assigning locations to each operand.
@@ -2446,29 +2449,36 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
 
   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
     if (IsPICCall) {
-      InternalLinkage = G->getGlobal()->hasInternalLinkage();
+      const GlobalValue *Val = G->getGlobal();
+      InternalLinkage = Val->hasInternalLinkage();
 
       if (InternalLinkage)
         Callee = getAddrLocal(G, Ty, DAG, HasMips64);
       else if (LargeGOT)
         Callee = getAddrGlobalLargeGOT(G, Ty, DAG, MipsII::MO_CALL_HI16,
-                                       MipsII::MO_CALL_LO16);
+                                       MipsII::MO_CALL_LO16, Chain,
+                                       FuncInfo->callPtrInfo(Val));
       else
-        Callee = getAddrGlobal(G, Ty, DAG, MipsII::MO_GOT_CALL);
+        Callee = getAddrGlobal(G, Ty, DAG, MipsII::MO_GOT_CALL, Chain,
+                               FuncInfo->callPtrInfo(Val));
     } else
       Callee = DAG.getTargetGlobalAddress(G->getGlobal(), DL, getPointerTy(), 0,
                                           MipsII::MO_NO_FLAG);
     GlobalOrExternal = true;
   }
   else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
+    const char *Sym = S->getSymbol();
+
     if (!IsN64 && !IsPIC) // !N64 && static
-      Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy(),
+      Callee = DAG.getTargetExternalSymbol(Sym, getPointerTy(),
                                             MipsII::MO_NO_FLAG);
     else if (LargeGOT)
       Callee = getAddrGlobalLargeGOT(S, Ty, DAG, MipsII::MO_CALL_HI16,
-                                     MipsII::MO_CALL_LO16);
+                                     MipsII::MO_CALL_LO16, Chain,
+                                     FuncInfo->callPtrInfo(Sym));
     else // N64 || PIC
-      Callee = getAddrGlobal(S, Ty, DAG, MipsII::MO_GOT_CALL);
+      Callee = getAddrGlobal(S, Ty, DAG, MipsII::MO_GOT_CALL, Chain,
+                             FuncInfo->callPtrInfo(Sym));
 
     GlobalOrExternal = true;
   }
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.h b/llvm/lib/Target/Mips/MipsISelLowering.h
index 7d9ab6a82e7..aa4bcc97214 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.h
+++ b/llvm/lib/Target/Mips/MipsISelLowering.h
@@ -275,12 +275,12 @@ namespace llvm {
     // (load (wrapper $gp, %got(sym)))
     template<class NodeTy>
     SDValue getAddrGlobal(NodeTy *N, EVT Ty, SelectionDAG &DAG,
-                          unsigned Flag) const {
+                          unsigned Flag, SDValue Chain,
+                          const MachinePointerInfo &PtrInfo) const {
       SDLoc DL(N);
       SDValue Tgt = DAG.getNode(MipsISD::Wrapper, DL, Ty, getGlobalReg(DAG, Ty),
                                 getTargetNode(N, Ty, DAG, Flag));
-      return DAG.getLoad(Ty, DL, DAG.getEntryNode(), Tgt,
-                         MachinePointerInfo::getGOT(), false, false, false, 0);
+      return DAG.getLoad(Ty, DL, Chain, Tgt, PtrInfo, false, false, false, 0);
     }
 
     // This method creates the following nodes, which are necessary for
@@ -289,15 +289,17 @@ namespace llvm {
     // (load (wrapper (add %hi(sym), $gp), %lo(sym)))
     template<class NodeTy>
     SDValue getAddrGlobalLargeGOT(NodeTy *N, EVT Ty, SelectionDAG &DAG,
-                                  unsigned HiFlag, unsigned LoFlag) const {
+                                  unsigned HiFlag, unsigned LoFlag,
+                                  SDValue Chain,
+                                  const MachinePointerInfo &PtrInfo) const {
       SDLoc DL(N);
       SDValue Hi = DAG.getNode(MipsISD::Hi, DL, Ty,
                                getTargetNode(N, Ty, DAG, HiFlag));
       Hi = DAG.getNode(ISD::ADD, DL, Ty, Hi, getGlobalReg(DAG, Ty));
       SDValue Wrapper = DAG.getNode(MipsISD::Wrapper, DL, Ty, Hi,
                                     getTargetNode(N, Ty, DAG, LoFlag));
-      return DAG.getLoad(Ty, DL, DAG.getEntryNode(), Wrapper,
-                         MachinePointerInfo::getGOT(), false, false, false, 0);
+      return DAG.getLoad(Ty, DL, Chain, Wrapper, PtrInfo, false, false, false,
+                         0);
     }
 
     // This method creates the following nodes, which are necessary for