[BPF] Remove exit-on-error from tests (PR27768, PR27769)

[rovka]

Summary

The exit-on-error flag is necessary to avoid some assertions/unreachables. We can get past them by creating a few dummy nodes.

Fixes PR27768, PR27769.

Last patch removing exit-on-error on the BPF side :)

[ast]

looks good. thanks!

lib/Target/BPF/BPFISelLowering.cpp

 }
 
 SDValue
 BPFTargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
                                bool IsVarArg,
                                const SmallVectorImpl<ISD::OutputArg> &Outs,
                                const SmallVectorImpl<SDValue> &OutVals,
                                SDLoc DL, SelectionDAG &DAG) const {
+  unsigned Opc = BPFISD::RET_FLAG;
 
   // CCValAssign - represent the assignment of the return value to a location
   SmallVector<CCValAssign, 16> RVLocs;
   MachineFunction &MF = DAG.getMachineFunction();
 
   // CCState - Info about the registers and stack slot.
   CCState CCInfo(CallConv, IsVarArg, MF, RVLocs, *DAG.getContext());
 
   if (MF.getFunction()->getReturnType()->isAggregateType()) {
     fail(DL, DAG, "only integer returns supported");
+    return DAG.getNode(Opc, DL, MVT::Other, Chain);
   }
 
   // Analize return values.
   CCInfo.AnalyzeReturn(Outs, RetCC_BPF64);
 
   SDValue Flag;
   SmallVector<SDValue, 4> RetOps(1, Chain);
 
   // Copy the result values into the output registers.
   for (unsigned i = 0; i != RVLocs.size(); ++i) {
     CCValAssign &VA = RVLocs[i];
     assert(VA.isRegLoc() && "Can only return in registers!");
 
     Chain = DAG.getCopyToReg(Chain, DL, VA.getLocReg(), OutVals[i], Flag);
 
     // Guarantee that all emitted copies are stuck together,
     // avoiding something bad.
     Flag = Chain.getValue(1);
     RetOps.push_back(DAG.getRegister(VA.getLocReg(), VA.getLocVT()));
   }
 
-  unsigned Opc = BPFISD::RET_FLAG;
   RetOps[0] = Chain; // Update chain.
 
   // Add the flag if we have it.
   if (Flag.getNode())
     RetOps.push_back(Flag);
 
   return DAG.getNode(Opc, DL, MVT::Other, RetOps);
 }
 
 SDValue BPFTargetLowering::LowerCallResult(
     SDValue Chain, SDValue InFlag, CallingConv::ID CallConv, bool IsVarArg,
     const SmallVectorImpl<ISD::InputArg> &Ins, SDLoc DL, SelectionDAG &DAG,
     SmallVectorImpl<SDValue> &InVals) const {
 
   MachineFunction &MF = DAG.getMachineFunction();
   // Assign locations to each value returned by this call.
   SmallVector<CCValAssign, 16> RVLocs;
   CCState CCInfo(CallConv, IsVarArg, MF, RVLocs, *DAG.getContext());
 
   if (Ins.size() >= 2) {
     fail(DL, DAG, "only small returns supported");
+    for (unsigned i = 0, e = Ins.size(); i != e; ++i)
+      InVals.push_back(DAG.getConstant(0, DL, Ins[i].VT));
+    return DAG.getCopyFromReg(Chain, DL, 1, Ins[0].VT, InFlag).getValue(1);
   }
 
   CCInfo.AnalyzeCallResult(Ins, RetCC_BPF64);
 
   // Copy all of the result registers out of their specified physreg.
   for (auto &Val : RVLocs) {
     Chain = DAG.getCopyFromReg(Chain, DL, Val.getLocReg(),
                                Val.getValVT(), InFlag).getValue(1);

test/CodeGen/BPF/struct_ret1.ll

-; RUN: not llc -march=bpf -exit-on-error < %s 2> %t1
+; RUN: not llc -march=bpf < %s 2> %t1
 ; RUN: FileCheck %s < %t1
 ; CHECK: only integer returns
 
 %struct.S = type { i32, i32, i32 }
 
 @s = common global %struct.S zeroinitializer, align 4
 
 ; Function Attrs: nounwind readonly uwtable
 define { i64, i32 } @bar(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) #0 {
 entry:
   %retval.sroa.0.0.copyload = load i64, i64* bitcast (%struct.S* @s to i64*), align 4
   %retval.sroa.2.0.copyload = load i32, i32* getelementptr inbounds (%struct.S, %struct.S* @s, i64 0, i32 2), align 4
   %.fca.0.insert = insertvalue { i64, i32 } undef, i64 %retval.sroa.0.0.copyload, 0
   %.fca.1.insert = insertvalue { i64, i32 } %.fca.0.insert, i32 %retval.sroa.2.0.copyload, 1
   ret { i64, i32 } %.fca.1.insert
 }

test/CodeGen/BPF/struct_ret2.ll

-; RUN: not llc -march=bpf -exit-on-error < %s 2> %t1
+; RUN: not llc -march=bpf < %s 2> %t1
 ; RUN: FileCheck %s < %t1
 ; CHECK: only small returns
 
 ; Function Attrs: nounwind uwtable
 define { i64, i32 } @foo(i32 %a, i32 %b, i32 %c) #0 {
 entry:
   %call = tail call { i64, i32 } @bar(i32 %a, i32 %b, i32 %c, i32 1, i32 2) #3
   ret { i64, i32 } %call
 }
 
 declare { i64, i32 } @bar(i32, i32, i32, i32, i32) #1