Fix ARM SjLj-EH dispatch setup code. <rdar://problem/10444602>

The EmitBasePointerRecalculation function has 2 problems, one minor and one
fatal.  The minor problem is that it inserts the code at the setjmp
instead of in the dispatch block.  The fatal problem is that at the point
where this code runs, we don't know whether there will be a base pointer,
so the entire function is a no-op.  The base pointer recalculation needs to
be handled as it was before, by inserting a pseudo instruction that gets
expanded late.

Most of the support for the old approach is still here, but it no longer
has any connection to the eh_sjlj_dispatchsetup intrinsic.  Clean up the
parts related to the intrinsic and just generate the pseudo instruction
directly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144781 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 4 insertions, 74 deletions

diff --git a/lib/Target/ARM/ARMExpandPseudoInsts.cpp b/lib/Target/ARM/ARMExpandPseudoInsts.cpp
index fb7d96a2c3..fc464ead2c 100644
--- a/lib/Target/ARM/ARMExpandPseudoInsts.cpp
+++ b/lib/Target/ARM/ARMExpandPseudoInsts.cpp
@@ -824,7 +824,7 @@ bool ARMExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
       MI.eraseFromParent();
       return true;
     }
-    case ARM::Int_eh_sjlj_dispatchsetup: {
+    case ARM::eh_sjlj_dispatchsetup: {
       MachineFunction &MF = *MI.getParent()->getParent();
       const ARMBaseInstrInfo *AII =
         static_cast<const ARMBaseInstrInfo*>(TII);
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 8783ac09ee..8c4c06fa8f 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -686,7 +686,6 @@ ARMTargetLowering::ARMTargetLowering(TargetMachine &TM)
   if (Subtarget->isTargetDarwin()) {
     setOperationAction(ISD::EH_SJLJ_SETJMP, MVT::i32, Custom);
     setOperationAction(ISD::EH_SJLJ_LONGJMP, MVT::Other, Custom);
-    setOperationAction(ISD::EH_SJLJ_DISPATCHSETUP, MVT::Other, Custom);
     setLibcallName(RTLIB::UNWIND_RESUME, "_Unwind_SjLj_Resume");
   }
 
@@ -863,7 +862,6 @@ const char *ARMTargetLowering::getTargetNodeName(unsigned Opcode) const {
 
   case ARMISD::EH_SJLJ_SETJMP: return "ARMISD::EH_SJLJ_SETJMP";
   case ARMISD::EH_SJLJ_LONGJMP:return "ARMISD::EH_SJLJ_LONGJMP";
-  case ARMISD::EH_SJLJ_DISPATCHSETUP:return "ARMISD::EH_SJLJ_DISPATCHSETUP";
 
   case ARMISD::TC_RETURN:     return "ARMISD::TC_RETURN";
 
@@ -2212,14 +2210,6 @@ SDValue ARMTargetLowering::LowerGLOBAL_OFFSET_TABLE(SDValue Op,
 }
 
 SDValue
-ARMTargetLowering::LowerEH_SJLJ_DISPATCHSETUP(SDValue Op, SelectionDAG &DAG)
-  const {
-  DebugLoc dl = Op.getDebugLoc();
-  return DAG.getNode(ARMISD::EH_SJLJ_DISPATCHSETUP, dl, MVT::Other,
-                     Op.getOperand(0), Op.getOperand(1));
-}
-
-SDValue
 ARMTargetLowering::LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const {
   DebugLoc dl = Op.getDebugLoc();
   SDValue Val = DAG.getConstant(0, MVT::i32);
@@ -5024,7 +5014,6 @@ SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::GLOBAL_OFFSET_TABLE: return LowerGLOBAL_OFFSET_TABLE(Op, DAG);
   case ISD::EH_SJLJ_SETJMP: return LowerEH_SJLJ_SETJMP(Op, DAG);
   case ISD::EH_SJLJ_LONGJMP: return LowerEH_SJLJ_LONGJMP(Op, DAG);
-  case ISD::EH_SJLJ_DISPATCHSETUP: return LowerEH_SJLJ_DISPATCHSETUP(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG,
                                                                Subtarget);
   case ISD::BITCAST:       return ExpandBITCAST(Op.getNode(), DAG);
@@ -5566,52 +5555,6 @@ ARMTargetLowering::EmitAtomicBinary64(MachineInstr *MI, MachineBasicBlock *BB,
   return BB;
 }
 
-/// EmitBasePointerRecalculation - For functions using a base pointer, we
-/// rematerialize it (via the frame pointer).
-void ARMTargetLowering::
-EmitBasePointerRecalculation(MachineInstr *MI, MachineBasicBlock *MBB,
-                             MachineBasicBlock *DispatchBB) const {
-  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
-  const ARMBaseInstrInfo *AII = static_cast<const ARMBaseInstrInfo*>(TII);
-  MachineFunction &MF = *MI->getParent()->getParent();
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  const ARMBaseRegisterInfo &RI = AII->getRegisterInfo();
-
-  if (!RI.hasBasePointer(MF)) return;
-
-  MachineBasicBlock::iterator MBBI = MI;
-
-  int32_t NumBytes = AFI->getFramePtrSpillOffset();
-  unsigned FramePtr = RI.getFrameRegister(MF);
-  assert(MF.getTarget().getFrameLowering()->hasFP(MF) &&
-         "Base pointer without frame pointer?");
-
-  if (AFI->isThumb2Function())
-    llvm::emitT2RegPlusImmediate(*MBB, MBBI, MI->getDebugLoc(), ARM::R6,
-                                 FramePtr, -NumBytes, ARMCC::AL, 0, *AII);
-  else if (AFI->isThumbFunction())
-    llvm::emitThumbRegPlusImmediate(*MBB, MBBI, MI->getDebugLoc(), ARM::R6,
-                                    FramePtr, -NumBytes, *AII, RI);
-  else
-    llvm::emitARMRegPlusImmediate(*MBB, MBBI, MI->getDebugLoc(), ARM::R6,
-                                  FramePtr, -NumBytes, ARMCC::AL, 0, *AII);
-
-  if (!RI.needsStackRealignment(MF)) return;
-
-  // If there's dynamic realignment, adjust for it.
-  MachineFrameInfo *MFI = MF.getFrameInfo();
-  unsigned MaxAlign = MFI->getMaxAlignment();
-  assert(!AFI->isThumb1OnlyFunction());
-
-  // Emit bic r6, r6, MaxAlign
-  unsigned bicOpc = AFI->isThumbFunction() ? ARM::t2BICri : ARM::BICri;
-  AddDefaultCC(
-    AddDefaultPred(
-      BuildMI(*MBB, MBBI, MI->getDebugLoc(), TII->get(bicOpc), ARM::R6)
-      .addReg(ARM::R6, RegState::Kill)
-      .addImm(MaxAlign - 1)));
-}
-
 /// SetupEntryBlockForSjLj - Insert code into the entry block that creates and
 /// registers the function context.
 void ARMTargetLowering::
@@ -5646,8 +5589,6 @@ SetupEntryBlockForSjLj(MachineInstr *MI, MachineBasicBlock *MBB,
     MF->getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
                              MachineMemOperand::MOStore, 4, 4);
 
-  EmitBasePointerRecalculation(MI, MBB, DispatchBB);
-
   // Load the address of the dispatch MBB into the jump buffer.
   if (isThumb2) {
     // Incoming value: jbuf
@@ -5821,6 +5762,8 @@ EmitSjLjDispatchBlock(MachineInstr *MI, MachineBasicBlock *MBB) const {
                              MachineMemOperand::MOLoad |
                              MachineMemOperand::MOVolatile, 4, 4);
 
+  BuildMI(DispatchBB, dl, TII->get(ARM::eh_sjlj_dispatchsetup));
+
   unsigned NumLPads = LPadList.size();
   if (Subtarget->isThumb2()) {
     unsigned NewVReg1 = MRI->createVirtualRegister(TRC);
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 2cca40b374..b8dc4bf531 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -81,7 +81,6 @@ namespace llvm {
 
       EH_SJLJ_SETJMP,         // SjLj exception handling setjmp.
       EH_SJLJ_LONGJMP,        // SjLj exception handling longjmp.
-      EH_SJLJ_DISPATCHSETUP,  // SjLj exception handling dispatch setup.
 
       TC_RETURN,    // Tail call return pseudo.
 
@@ -410,7 +409,6 @@ namespace llvm {
                              ISD::ArgFlagsTy Flags) const;
     SDValue LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
-    SDValue LowerEH_SJLJ_DISPATCHSETUP(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
                                     const ARMSubtarget *Subtarget) const;
     SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
@@ -520,9 +518,6 @@ namespace llvm {
                                                bool signExtend,
                                                ARMCC::CondCodes Cond) const;
 
-    void EmitBasePointerRecalculation(MachineInstr *MI, MachineBasicBlock *MBB,
-                                      MachineBasicBlock *DispatchBB) const;
-
     void SetupEntryBlockForSjLj(MachineInstr *MI,
                                 MachineBasicBlock *MBB,
                                 MachineBasicBlock *DispatchBB, int FI) const;
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index da3a1be71b..7c7e58c7b9 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -58,8 +58,6 @@ def SDT_ARMEH_SJLJ_Setjmp : SDTypeProfile<1, 2, [SDTCisInt<0>, SDTCisPtrTy<1>,
                                                  SDTCisInt<2>]>;
 def SDT_ARMEH_SJLJ_Longjmp: SDTypeProfile<0, 2, [SDTCisPtrTy<0>, SDTCisInt<1>]>;
 
-def SDT_ARMEH_SJLJ_DispatchSetup: SDTypeProfile<0, 1, [SDTCisInt<0>]>;
-
 def SDT_ARMMEMBARRIER     : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 def SDT_ARMPREFETCH : SDTypeProfile<0, 3, [SDTCisPtrTy<0>, SDTCisSameAs<1, 2>,
@@ -143,9 +141,6 @@ def ARMeh_sjlj_setjmp: SDNode<"ARMISD::EH_SJLJ_SETJMP",
                                SDT_ARMEH_SJLJ_Setjmp, [SDNPHasChain]>;
 def ARMeh_sjlj_longjmp: SDNode<"ARMISD::EH_SJLJ_LONGJMP",
                                SDT_ARMEH_SJLJ_Longjmp, [SDNPHasChain]>;
-def ARMeh_sjlj_dispatchsetup: SDNode<"ARMISD::EH_SJLJ_DISPATCHSETUP",
-                               SDT_ARMEH_SJLJ_DispatchSetup, [SDNPHasChain]>;
-
 
 def ARMMemBarrier     : SDNode<"ARMISD::MEMBARRIER", SDT_ARMMEMBARRIER,
                                [SDNPHasChain]>;
@@ -4674,10 +4669,7 @@ def Int_eh_sjlj_longjmp : PseudoInst<(outs), (ins GPR:$src, GPR:$scratch),
 // handled when the pseudo is expanded (which happens before any passes
 // that need the instruction size).
 let isBarrier = 1, hasSideEffects = 1 in
-def Int_eh_sjlj_dispatchsetup :
- PseudoInst<(outs), (ins GPR:$src), NoItinerary,
-            [(ARMeh_sjlj_dispatchsetup GPR:$src)]>,
-              Requires<[IsDarwin]>;
+def eh_sjlj_dispatchsetup : PseudoInst<(outs), (ins), NoItinerary, []>;
 
 //===----------------------------------------------------------------------===//
 // Non-Instruction Patterns