[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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191591 91177308-0d34-0410-b5e6-96231b3b80d8

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),
+      ExternalSymbolSDNode *S = cast<ExternalSymbolSDNode>(JumpTarget);
-                                 JumpTarget.getValueType(), DAG,
+      JumpTarget = getAddrGlobal(S, JumpTarget.getValueType(), DAG,
-                                 MipsII::MO_GOT);
+                                 MipsII::MO_GOT, Chain,
+                                 FuncInfo->callPtrInfo(S->getSymbol()));
     } else
       RegsToPass.push_front(std::make_pair((unsigned)Mips::T9, Callee));
   }

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) &&
+    return !PSV->isConstant(0) && V != PseudoSourceValue::getStack();
-      (V != PseudoSourceValue::getStack());
 
   return true;
 }

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;
   }

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,
+      return DAG.getLoad(Ty, DL, Chain, Tgt, PtrInfo, false, false, false, 0);
-                         MachinePointerInfo::getGOT(), 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,
+      return DAG.getLoad(Ty, DL, Chain, Wrapper, PtrInfo, false, false, false,
-                         MachinePointerInfo::getGOT(), false, false, false, 0);
+                         0);
     }
 
     // This method creates the following nodes, which are necessary for

test/CodeGen/Mips/brdelayslot.ll

@@ -160,7 +160,14 @@ for.end:                                          ; preds = %for.body, %entry
 ;
 ; SUCCBB-LABEL:      succbbs_br1:
 ; SUCCBB:      beqz ${{[0-9]+}}, $BB
-; SUCCBB-NEXT: lw $25, %call16(foo100)
+; SUCCBB-NEXT: lw ${{[0-9]+}}, %got(foo101)(${{[0-9]+}})
+
+define internal fastcc void @foo101() {
+entry:
+  tail call void @foo100()
+  tail call void @foo100()
+  ret void
+}
 
 define void @succbbs_br1(i32 %a) {
 entry:
@@ -168,7 +175,7 @@ entry:
   br i1 %tobool, label %if.end, label %if.then
 
 if.then:                                          ; preds = %entry
-  tail call void @foo100() #1
+  tail call fastcc void @foo101()
   br label %if.end
 
 if.end:                                           ; preds = %entry, %if.then

test/CodeGen/Mips/i64arg.ll

@@ -9,11 +9,11 @@ entry:
 ; CHECK: lw  $25, %call16(ff1)
 ; CHECK: jalr
   tail call void @ff1(i32 %i, i64 1085102592623924856) nounwind
-; CHECK: lw $25, %call16(ff2)
+; CHECK-DAG: lw $25, %call16(ff2)
-; CHECK: lw $[[R2:[0-9]+]], 80($sp)
+; CHECK-DAG: lw $[[R2:[0-9]+]], 80($sp)
-; CHECK: lw $[[R3:[0-9]+]], 84($sp)
+; CHECK-DAG: lw $[[R3:[0-9]+]], 84($sp)
-; CHECK: move $4, $[[R2]]
+; CHECK-DAG: move $4, $[[R2]]
-; CHECK: move $5, $[[R3]]
+; CHECK-DAG: move $5, $[[R3]]
 ; CHECK: jalr $25
   tail call void @ff2(i64 %ll, double 3.000000e+00) nounwind
   %sub = add nsw i32 %i, -1

test/CodeGen/Mips/largeimmprinting.ll

@@ -18,11 +18,11 @@ entry:
 ; 64:  dsll  $[[R0]], $[[R0]], 48
 ; 64:  daddiu  $[[R0]], $[[R0]], -1
 ; 64:  dsll  $[[R0]], $[[R0]], 16
-; 64:  daddiu  $[[R0]], $[[R0]], -48
+; 64:  daddiu  $[[R0]], $[[R0]], -32
 ; 64:  daddu $sp, $sp, $[[R0]]
 ; 64:  lui $[[R1:[0-9]+]], 1
 ; 64:  daddu $[[R1]], $sp, $[[R1]]
-; 64:  sd  $ra, 40($[[R1]])
+; 64:  sd  $ra, 24($[[R1]])
 
   %agg.tmp = alloca %struct.S1, align 1
   %tmp = getelementptr inbounds %struct.S1* %agg.tmp, i32 0, i32 0, i32 0

test/CodeGen/Mips/lazy-binding.ll

@@ -0,0 +1,41 @@
+; RUN: llc -march=mipsel < %s | FileCheck %s
+
+; CHECK-LABEL: foo6:
+; CHECK: %while.body
+; CHECK: lw  $25, %call16(foo2)(${{[0-9]+}})
+; CHECK: jalr $25
+; CHECK: %while.end
+
+define void @foo6(i32 %n) {
+entry:
+  %tobool1 = icmp eq i32 %n, 0
+  br i1 %tobool1, label %while.end, label %while.body
+
+while.body:                                       ; preds = %entry, %while.body
+  %n.addr.02 = phi i32 [ %dec, %while.body ], [ %n, %entry ]
+  %dec = add nsw i32 %n.addr.02, -1
+  tail call void @foo2()
+  %tobool = icmp eq i32 %dec, 0
+  br i1 %tobool, label %while.end, label %while.body
+
+while.end:                                        ; preds = %while.body, %entry
+  ret void
+}
+
+declare void @foo2()
+
+; CHECK-LABEL: foo1:
+; CHECK: lw $25, %call16(foo2)(${{[0-9]+}})
+; CHECK: jalr $25
+; CHECK: lw $25, %call16(foo2)(${{[0-9]+}})
+; CHECK: jalr $25
+; CHECK: lw $25, %call16(foo2)(${{[0-9]+}})
+; CHECK: jalr $25
+
+define void @foo1() {
+entry:
+  tail call void @foo2()
+  tail call void @foo2()
+  tail call void @foo2()
+  ret void
+}