[BPF] Remove exit-on-error flag in test (PR27767)

[rovka]

Summary

The exit-on-error flag is needed to avoid an assert where llvm::SelectionDAGISel::LowerArguments doesn't create enough arguments. Fill up with zeroes to reach the right number of args.

Fixes PR27767.

[ast]

lib/Target/BPF/BPFISelLowering.cpp

202

bpf backend doesn't like 'undef' since most likely it would mean that generated code will be reject by the kernel verifier with hard to decipher error. Can you change it to use const zero instead? In general continuing after "too many args" is hard. At least with zero there is a chance that generated code is somewhat sane.

[rovka]

Updated to use zeroes instead of undef.

[ast]

thanks!

lib/Target/BPF/BPFISelLowering.cpp

if (VA.isRegLoc()) {
 
         if (VA.getLocInfo() != CCValAssign::Full)
           ArgValue = DAG.getNode(ISD::TRUNCATE, DL, VA.getValVT(), ArgValue);
 
         InVals.push_back(ArgValue);
       }
     } else {
       fail(DL, DAG, "defined with too many args");
+      InVals.push_back(DAG.getUNDEF(MVT::Other));
     }
   }
 
   if (IsVarArg || MF.getFunction()->hasStructRetAttr()) {
     fail(DL, DAG, "functions with VarArgs or StructRet are not supported");
   }
 
   return Chain;

test/CodeGen/BPF/many_args2.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: too many args
 
 ; Function Attrs: nounwind readnone uwtable
 define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f) #0 {
 entry:
   ret i32 1
 }
 
 ; Function Attrs: nounwind readnone uwtable
 define i32 @foo(i32 %a, i32 %b, i32 %c) #0 {
 entry:
   ret i32 1
 }