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[WinEH] Don't inline an 'unwinds to caller' cleanupret into funclets which locally unwind

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It is problematic if the inlinee has a cleanupret which unwinds to
caller and we inline it into a call site which doesn't unwind.

If the funclet unwinds anywhere other than to the caller,
then we will give the funclet two unwind destinations.
This will result in a verifier failure.

Seeing as how the caller wasn't an invoke (which would locally unwind)
and that the funclet cannot unwind to caller, we must conclude that an
'unwind to caller' cleanupret is dynamically unreachable.

This fixes PR26698.

Differential Revision: http://reviews.llvm.org/D17536

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261656 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Majnemer 2016-02-23 17:11:04 +00:00
parent a10a4f18bf
commit e759b51ef4
2 changed files with 86 additions and 0 deletions
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21
lib/Transforms/Utils/InlineFunction.cpp
View File

@ -1420,6 +1420,19 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
}
}
// Determine if we are dealing with a call in an EHPad which does not unwind
// to caller.
bool EHPadForCallUnwindsLocally = false;
if (CallSiteEHPad && CS.isCall()) {
UnwindDestMemoTy FuncletUnwindMap;
Value *CallSiteUnwindDestToken =
getUnwindDestToken(CallSiteEHPad, FuncletUnwindMap);
EHPadForCallUnwindsLocally =
CallSiteUnwindDestToken &&
!isa<ConstantTokenNone>(CallSiteUnwindDestToken);
}
// Get an iterator to the last basic block in the function, which will have
// the new function inlined after it.
Function::iterator LastBlock = --Caller->end();
@ -1763,6 +1776,14 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
OpBundles.clear();
}
// It is problematic if the inlinee has a cleanupret which unwinds to
// caller and we inline it into a call site which doesn't unwind but into
// an EH pad that does. Such an edge must be dynamically unreachable.
// As such, we replace the cleanupret with unreachable.
if (auto *CleanupRet = dyn_cast<CleanupReturnInst>(BB->getTerminator()))
if (CleanupRet->unwindsToCaller() && EHPadForCallUnwindsLocally)
changeToUnreachable(CleanupRet, /*UseLLVMTrap=*/false);
Instruction *I = BB->getFirstNonPHI();
if (!I->isEHPad())
continue;

65
test/Transforms/Inline/pr26698.ll Normal file
View File

@ -0,0 +1,65 @@
; RUN: opt -S -inline < %s | FileCheck %s
target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
target triple = "i686-pc-windows-msvc18.0.0"
declare void @g(i32)
define void @f() personality i32 (...)* @__CxxFrameHandler3 {
entry:
invoke void @g(i32 0)
to label %invoke.cont unwind label %cs.bb
invoke.cont:
ret void
cs.bb:
%cs = catchswitch within none [label %cp.bb] unwind label %cleanup.bb
cp.bb:
%cpouter1 = catchpad within %cs [i8* null, i32 0, i8* null]
call void @dtor() #1 [ "funclet"(token %cpouter1) ]
catchret from %cpouter1 to label %invoke.cont
cleanup.bb:
%cpouter2 = cleanuppad within none []
call void @g(i32 1) [ "funclet"(token %cpouter2) ]
cleanupret from %cpouter2 unwind to caller
}
declare i32 @__CxxFrameHandler3(...)
; Function Attrs: nounwind
define internal void @dtor() #1 personality i32 (...)* @__CxxFrameHandler3 {
entry:
invoke void @g(i32 2)
to label %invoke.cont unwind label %ehcleanup1
invoke.cont:
ret void
ehcleanup1:
%cpinner1 = cleanuppad within none []
invoke void @g(i32 3) [ "funclet" (token %cpinner1) ]
to label %done unwind label %ehcleanup2
done:
unreachable
ehcleanup2:
%cpinner2 = cleanuppad within %cpinner1 []
call void @g(i32 4) [ "funclet" (token %cpinner2) ]
cleanupret from %cpinner2 unwind to caller
}
; CHECK-LABEL: define void @f(
; CHECK: %[[cs:.*]] = catchswitch within none
; CHECK: %[[cpouter1:.*]] = catchpad within %[[cs]]
; CHECK: %[[cpinner1:.*]] = cleanuppad within %[[cpouter1]]
; CHECK: %[[cpinner2:.*]] = cleanuppad within %[[cpinner1]]
; CHECK-NEXT: call void @g(i32 4) #0 [ "funclet"(token %[[cpinner2]]) ]
; CHECK-NEXT: unreachable
attributes #1 = { nounwind }