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[Verifier] Diagnose when unwinding out of cycles of blocks

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Generally speaking, this can only happen with unreachable code.
However, neglecting to check for this condition would lead us to loop
forever.

llvm-svn: 262284
This commit is contained in:
David Majnemer 2016-03-01 01:19:05 +00:00
parent 4834994813
commit 54603e7ab8
2 changed files with 23 additions and 1 deletions
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5
lib/IR/Verifier.cpp
View File

@ -3064,6 +3064,7 @@ void Verifier::visitEHPadPredecessors(Instruction &I) {
}
// The edge may exit from zero or more nested pads.
SmallSet<Value *, 8> Seen;
for (;; FromPad = getParentPad(FromPad)) {
Assert(FromPad != ToPad,
"EH pad cannot handle exceptions raised within it", FromPad, TI);
@ -3073,6 +3074,8 @@ void Verifier::visitEHPadPredecessors(Instruction &I) {
}
Assert(!isa<ConstantTokenNone>(FromPad),
"A single unwind edge may only enter one EH pad", TI);
Assert(Seen.insert(FromPad).second,
"EH pad jumps through a cycle of pads", FromPad);
}
}
}
@ -3171,7 +3174,7 @@ void Verifier::visitFuncletPadInst(FuncletPadInst &FPI) {
User *FirstUser = nullptr;
Value *FirstUnwindPad = nullptr;
SmallVector<FuncletPadInst *, 8> Worklist({&FPI});
std::set<FuncletPadInst *> Seen;
SmallSet<FuncletPadInst *, 8> Seen;
while (!Worklist.empty()) {
FuncletPadInst *CurrentPad = Worklist.pop_back_val();

19
test/Verifier/invalid-eh.ll
View File

@ -22,6 +22,7 @@
; RUN: sed -e s/.T22:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK22 %s
; RUN: sed -e s/.T23:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK23 %s
; RUN: sed -e s/.T24:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK24 %s
; RUN: sed -e s/.T25:// %s | not opt -verify -disable-output 2>&1 | FileCheck --check-prefix=CHECK25 %s
declare void @g()
@ -420,3 +421,21 @@ declare void @g()
;T24: exit:
;T24: unreachable
;T24: }
;T25: define void @f() personality void ()* @g {
;T25: entry:
;T25: unreachable
;T25:
;T25: catch.dispatch:
;T25: %cs = catchswitch within %cp2 [label %catch] unwind label %ehcleanup
;T25: ; CHECK25: EH pad jumps through a cycle of pads
;T25: ; CHECK25: %cs = catchswitch within %cp2 [label %catch] unwind label %ehcleanup
;T25:
;T25: catch:
;T25: %cp2 = catchpad within %cs [i8* null, i32 64, i8* null]
;T25: unreachable
;T25:
;T25: ehcleanup:
;T25: %cp3 = cleanuppad within none []
;T25: cleanupret from %cp3 unwind to caller
;T25: }