[WinEH] Disallow cyclic unwinds

Summary:
Funclet-based EH personalities/tables likely can't handle these, and they
can't be generated at source, so make them officially illegal in IR as
well.


Reviewers: andrew.w.kaylor, rnk, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15963

llvm-svn: 257274

2 files changed, 57 insertions, 42 deletions

diff --git a/llvm/test/CodeGen/WinEH/wineh-cloning.ll b/llvm/test/CodeGen/WinEH/wineh-cloning.ll
index 3c1793a3bd7..748c07df173 100644
--- a/llvm/test/CodeGen/WinEH/wineh-cloning.ll
+++ b/llvm/test/CodeGen/WinEH/wineh-cloning.ll
@@ -233,48 +233,6 @@ exit:
 ; CHECK-NEXT:   br label %outer.ret
 
 
-define void @test9() personality i32 (...)* @__C_specific_handler {
-entry:
-  invoke void @f()
-    to label %invoke.cont unwind label %left
-invoke.cont:
-  invoke void @f()
-    to label %unreachable unwind label %right
-left:
-  %cp.left = cleanuppad within none []
-  call void @llvm.foo(i32 1)
-  invoke void @f() [ "funclet"(token %cp.left) ]
-    to label %unreachable unwind label %right
-right:
-  %cp.right = cleanuppad within none []
-  call void @llvm.foo(i32 2)
-  invoke void @f() [ "funclet"(token %cp.right) ]
-    to label %unreachable unwind label %left
-unreachable:
-  unreachable
-}
-; This is an irreducible loop with two funclets that enter each other.
-; CHECK-LABEL: define void @test9(
-; CHECK:     entry:
-; CHECK:               to label %invoke.cont unwind label %[[LEFT:.+]]
-; CHECK:     invoke.cont:
-; CHECK:               to label %[[UNREACHABLE_ENTRY:.+]] unwind label %[[RIGHT:.+]]
-; CHECK:     [[LEFT]]:
-; CHECK:       call void @llvm.foo(i32 1)
-; CHECK:       invoke void @f()
-; CHECK:               to label %[[UNREACHABLE_LEFT:.+]] unwind label %[[RIGHT]]
-; CHECK:     [[RIGHT]]:
-; CHECK:       call void @llvm.foo(i32 2)
-; CHECK:       invoke void @f()
-; CHECK:               to label %[[UNREACHABLE_RIGHT:.+]] unwind label %[[LEFT]]
-; CHECK:     [[UNREACHABLE_RIGHT]]:
-; CHECK:       unreachable
-; CHECK:     [[UNREACHABLE_LEFT]]:
-; CHECK:       unreachable
-; CHECK:     [[UNREACHABLE_ENTRY]]:
-; CHECK:       unreachable
-
-
 define void @test10() personality i32 (...)* @__CxxFrameHandler3 {
 entry:
   invoke void @f()
diff --git a/llvm/test/Verifier/invalid-eh.ll b/llvm/test/Verifier/invalid-eh.ll
index e5ad2abfb5e..af3d987a39b 100644
--- a/llvm/test/Verifier/invalid-eh.ll
+++ b/llvm/test/Verifier/invalid-eh.ll
@@ -15,6 +15,8 @@
 ; RUN: sed -e s/.T15:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK15 %s
 ; RUN: sed -e s/.T16:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK16 %s
 ; RUN: sed -e s/.T17:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK17 %s
+; RUN: sed -e s/.T18:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK18 %s
+; RUN: sed -e s/.T19:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK19 %s
 
 declare void @g()
 
@@ -282,3 +284,58 @@ declare void @g()
 ;T17:     cleanuppad within none []
 ;T17:     unreachable
 ;T17: }
+
+;T18: define void @f() personality void ()* @g {
+;T18:   entry:
+;T18:     invoke void @g()
+;T18:       to label %invoke.cont unwind label %left
+;T18:   invoke.cont:
+;T18:     invoke void @g()
+;T18:       to label %unreachable unwind label %right
+;T18:   left:
+;T18:     %cp.left = cleanuppad within none []
+;T18:     invoke void @g() [ "funclet"(token %cp.left) ]
+;T18:       to label %unreachable unwind label %right
+;T18:   right:
+;T18:     %cp.right = cleanuppad within none []
+;T18:     invoke void @g() [ "funclet"(token %cp.right) ]
+;T18:       to label %unreachable unwind label %left
+;T18:     ; CHECK18: EH pads can't handle each other's exceptions
+;T18:     ; CHECK18-NEXT: %cp.left = cleanuppad within none []
+;T18:     ; CHECK18-NEXT:  invoke void @g() [ "funclet"(token %cp.left) ]
+;T18:     ; CHECK18-NEXT:          to label %unreachable unwind label %right
+;T18:     ; CHECK18-NEXT:  %cp.right = cleanuppad within none []
+;T18:     ; CHECK18-NEXT:  invoke void @g() [ "funclet"(token %cp.right) ]
+;T18:     ; CHECK18-NEXT:          to label %unreachable unwind label %left
+;T18:   unreachable:
+;T18:     unreachable
+;T18: }
+
+;T19: define void @f() personality void ()* @g {
+;T19:   entry:
+;T19:     ret void
+;T19:   red:
+;T19:     %redpad = cleanuppad within none []
+;T19:     unreachable
+;T19:   red.inner:
+;T19:     %innerpad = cleanuppad within %redpad []
+;T19:     invoke void @g() [ "funclet"(token %innerpad) ]
+;T19:       to label %unreachable unwind label %green
+;T19:   green:
+;T19:     %greenswitch = catchswitch within none [label %catch] unwind label %blue
+;T19:   catch:
+;T19:     catchpad within %greenswitch [i32 42]
+;T19:     unreachable
+;T19:   blue:
+;T19:     %bluepad = cleanuppad within none []
+;T19:     cleanupret from %bluepad unwind label %red
+;T19:     ; CHECK19: EH pads can't handle each other's exceptions
+;T19:     ; CHECK19-NEXT: %redpad = cleanuppad within none []
+;T19:     ; CHECK19-NEXT: invoke void @g() [ "funclet"(token %innerpad) ]
+;T19:     ; CHECK19-NEXT:         to label %unreachable unwind label %green
+;T19:     ; CHECK19-NEXT: %greenswitch = catchswitch within none [label %catch] unwind label %blue
+;T19:     ; CHECK19-NEXT: %bluepad = cleanuppad within none []
+;T19:     ; CHECK19-NEXT: cleanupret from %bluepad unwind label %red
+;T19:   unreachable:
+;T19:     unreachable
+;T19: }