[WinEH] Verify catchswitch handlers

[JosephTremoulet]

Summary

The handler list must be nonempty and consist solely of CatchPads.

[majnemer]

LGTM

lib/IR/Verifier.cpp

3082

Might be good to have it as CatchSwitch.getNumHandlers() != 0 to make it more explicit. Either way works for me.

[JosephTremoulet]

address feedback

lib/IR/Verifier.cpp

Assert(I->isEHPad() && !isa<LandingPadInst>(I),
            "landingpad.",
            &CatchSwitch);
   }
 
   auto *ParentPad = CatchSwitch.getParentPad();
   Assert(isa<ConstantTokenNone>(ParentPad) || isa<FuncletPadInst>(ParentPad),
          "CatchSwitchInst has an invalid parent.", ParentPad);
 
+  Assert(CatchSwitch.getNumHandlers() != 0,
+         "CatchSwitchInst cannot have empty handler list", &CatchSwitch);
+
+  for (BasicBlock *Handler : CatchSwitch.handlers())
+    Assert(isa<CatchPadInst>(Handler->getFirstNonPHI()),
+           "CatchSwitchInst handlers must be catchpads", &CatchSwitch, Handler);
+
   visitTerminatorInst(CatchSwitch);
 }
 
 void Verifier::visitCleanupReturnInst(CleanupReturnInst &CRI) {
   Assert(isa<CleanupPadInst>(CRI.getOperand(0)),
          "CleanupReturnInst needs to be provided a CleanupPad", &CRI,
          CRI.getOperand(0));
 

test/Verifier/invalid-eh.ll

 ; RUN: sed -e s/.T1:// %s | not llvm-as -disable-output 2>&1 | FileCheck --check-prefix=CHECK1 %s
 ; RUN: sed -e s/.T2:// %s | not llvm-as -disable-output 2>&1 | FileCheck --check-prefix=CHECK2 %s
 ; RUN: sed -e s/.T3:// %s | not llvm-as -disable-output 2>&1 | FileCheck --check-prefix=CHECK3 %s
 ; RUN: sed -e s/.T4:// %s | not llvm-as -disable-output 2>&1 | FileCheck --check-prefix=CHECK4 %s
 ; RUN: sed -e s/.T5:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK5 %s
 ; RUN: sed -e s/.T6:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK6 %s
 ; RUN: sed -e s/.T7:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK7 %s
+; RUN: sed -e s/.T8:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK8 %s
 
 declare void @g()
 
 ;T1: define void @f() {
 ;T1:   entry:
 ;T1:     catchret from undef to label %next
 ;T1:     ; CHECK1: CatchReturnInst needs to be provided a CatchPad
 ;T1:   next:

 ;T7:     unreachable
 ;T7:   switch2:
 ;T7:     %cs2 = catchswitch within %cs1 [label %catch2] unwind to caller
 ;T7:     ; CHECK7: CatchSwitchInst has an invalid parent
 ;T7:   catch2:
 ;T7:     catchpad within %cs2 []
 ;T7:     unreachable
 ;T7: }
+
+;T8: define void @f() personality void ()* @g {
+;T8:   entry:
+;T8:     ret void
+;T8:   switch1:
+;T8:     %cs1 = catchswitch within none [ label %switch1 ] unwind to caller
+;T8:     ; CHECK8: CatchSwitchInst handlers must be catchpads
+;T8: }