[WinEH] Verify unwind edges against EH pad tree

Summary:
Funclet EH personalities require a tree-like nesting among funclets
(enforced by the ParentPad linkage in the IR), and also require that
unwind edges conform to certain rules with respect to the tree:
 - An unwind edge may exit 0 or more ancestor pads
 - An unwind edge must enter exactly one EH pad, which must be distinct
   from any exited pads
 - A cleanupret's edge must exit its cleanuppad

Describe these rules in the LangRef, and enforce them in the verifier.


Reviewers: rnk, majnemer, andrew.w.kaylor

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15961

llvm-svn: 257272

3 files changed, 91 insertions, 3 deletions

diff --git a/llvm/test/Bitcode/compatibility.ll b/llvm/test/Bitcode/compatibility.ll
index 34c4a073b54..ae12a24ede4 100644
--- a/llvm/test/Bitcode/compatibility.ll
+++ b/llvm/test/Bitcode/compatibility.ll
@@ -885,7 +885,8 @@ catchpad:
   ; CHECK-NEXT: br label %body
 
 body:
-  invoke void @f.ccc() to label %continue unwind label %terminate.inner
+  invoke void @f.ccc() [ "funclet"(token %catch) ]
+    to label %continue unwind label %terminate.inner
   catchret from %catch to label %return
   ; CHECK: catchret from %catch to label %return
 
diff --git a/llvm/test/Feature/exception.ll b/llvm/test/Feature/exception.ll
index 2634692f425..cbe2d0353cc 100644
--- a/llvm/test/Feature/exception.ll
+++ b/llvm/test/Feature/exception.ll
@@ -43,7 +43,7 @@ entry:
   invoke void @_Z3quxv() optsize
           to label %exit unwind label %pad
 cleanup:
-  cleanupret from %cp unwind label %pad
+  cleanupret from %cp unwind to caller
 pad:
   %cp = cleanuppad within none []
   br label %cleanup
@@ -57,7 +57,7 @@ entry:
   invoke void @_Z3quxv() optsize
           to label %exit unwind label %pad
 cleanup:
-  cleanupret from %0 unwind label %pad
+  cleanupret from %0 unwind to caller
 pad:
   %0 = cleanuppad within none []
   br label %cleanup
diff --git a/llvm/test/Verifier/invalid-eh.ll b/llvm/test/Verifier/invalid-eh.ll
index 21e88d4dcb3..e43a676495d 100644
--- a/llvm/test/Verifier/invalid-eh.ll
+++ b/llvm/test/Verifier/invalid-eh.ll
@@ -6,6 +6,11 @@
 ; 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
+; RUN: sed -e s/.T9:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK9 %s
+; RUN: sed -e s/.T10:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK10 %s
+; RUN: sed -e s/.T11:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK11 %s
+; RUN: sed -e s/.T12:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK12 %s
+; RUN: sed -e s/.T13:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK13 %s
 
 declare void @g()
 
@@ -96,3 +101,85 @@ declare void @g()
 ;T8:     %cs1 = catchswitch within none [ label %switch1 ] unwind to caller
 ;T8:     ; CHECK8: CatchSwitchInst handlers must be catchpads
 ;T8: }
+
+;T9: define void @f() personality void ()* @g {
+;T9:   entry:
+;T9:     ret void
+;T9:   cleanup:
+;T9:     %cp = cleanuppad within none []
+;T9:     invoke void @g() [ "funclet"(token %cp) ]
+;T9:       to label %exit unwind label %cleanup
+;T9:       ; CHECK9: EH pad cannot handle exceptions raised within it
+;T9:       ; CHECK9-NEXT: %cp = cleanuppad within none []
+;T9:       ; CHECK9-NEXT: invoke void @g() [ "funclet"(token %cp) ]
+;T9:   exit:
+;T9:     ret void
+;T9: }
+
+;T10: define void @f() personality void ()* @g {
+;T10:   entry:
+;T10:     ret void
+;T10:   cleanup1:
+;T10:     %cp1 = cleanuppad within none []
+;T10:     unreachable
+;T10:   switch:
+;T10:     %cs = catchswitch within %cp1 [label %catch] unwind to caller
+;T10:   catch:
+;T10:     %catchp1 = catchpad within %cs [i32 1]
+;T10:     unreachable
+;T10:   cleanup2:
+;T10:     %cp2 = cleanuppad within %catchp1 []
+;T10:     unreachable
+;T10:   cleanup3:
+;T10:     %cp3 = cleanuppad within %cp2 []
+;T10:     cleanupret from %cp3 unwind label %switch
+;T10:       ; CHECK10: EH pad cannot handle exceptions raised within it
+;T10:       ; CHECK10-NEXT: %cs = catchswitch within %cp1 [label %catch] unwind to caller
+;T10:       ; CHECK10-NEXT: cleanupret from %cp3 unwind label %switch
+;T10: }
+
+;T11: define void @f() personality void ()* @g {
+;T11:   entry:
+;T11:     ret void
+;T11:   cleanup1:
+;T11:     %cp1 = cleanuppad within none []
+;T11:     unreachable
+;T11:   cleanup2:
+;T11:     %cp2 = cleanuppad within %cp1 []
+;T11:     unreachable
+;T11:   switch:
+;T11:     %cs = catchswitch within none [label %catch] unwind label %cleanup2
+;T11:     ; CHECK11: A single unwind edge may only enter one EH pad
+;T11:     ; CHECK11-NEXT: %cs = catchswitch within none [label %catch] unwind label %cleanup2
+;T11:   catch:
+;T11:     catchpad within %cs [i32 1]
+;T11:     unreachable
+;T11: }
+
+;T12: define void @f() personality void ()* @g {
+;T12:   entry:
+;T12:     ret void
+;T12:   cleanup:
+;T12:     %cp = cleanuppad within none []
+;T12:     cleanupret from %cp unwind label %switch
+;T12:     ; CHECK12: A cleanupret must exit its cleanup
+;T12:     ; CHECK12-NEXT: cleanupret from %cp unwind label %switch
+;T12:   switch:
+;T12:     %cs = catchswitch within %cp [label %catch] unwind to caller
+;T12:   catch:
+;T12:     catchpad within %cs [i32 1]
+;T12:     unreachable
+;T12: }
+
+;T13: define void @f() personality void ()* @g {
+;T13:   entry:
+;T13:     ret void
+;T13:   switch:
+;T13:     %cs = catchswitch within none [label %catch] unwind label %switch
+;T13:     ; CHECK13: EH pad cannot handle exceptions raised within it
+;T13:     ; CHECK13-NEXT:  %cs = catchswitch within none [label %catch] unwind label %switch
+;T13:   catch:
+;T13:     catchpad within %cs [i32 0]
+;T13:     unreachable
+;T13: }
+