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ObjCARC: do not increment past the end of the BB 

The `BasicBlock::getFirstInsertionPt` call may return `std::end` for the
BB.  Dereferencing the end iterator results in an assertion failure
"(!NodePtr->isKnownSentinel()), function operator*".  Ensure that the
returned iterator is valid before dereferencing it.  If the end is
returned, move one position backward to get a valid insertion point.

llvm-svn: 316401
This commit is contained in:
Saleem Abdulrasool 2017-10-24 00:09:10 +00:00
parent 3d64d6ee54
commit 619b3269fd
2 changed files with 65 additions and 4 deletions
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12
llvm/lib/Transforms/ObjCARC/PtrState.cpp
View File

@ -250,10 +250,14 @@ void BottomUpPtrState::HandlePotentialUse(BasicBlock *BB, Instruction *Inst,
// If this is an invoke instruction, we're scanning it as part of
// one of its successor blocks, since we can't insert code after it
// in its own block, and we don't want to split critical edges.
if (isa<InvokeInst>(Inst))
InsertReverseInsertPt(&*BB->getFirstInsertionPt());
else
InsertReverseInsertPt(&*++Inst->getIterator());
BasicBlock::iterator InsertAfter;
if (isa<InvokeInst>(Inst)) {
const auto IP = BB->getFirstInsertionPt();
InsertAfter = IP == BB->end() ? std::prev(BB->end()) : IP;
} else {
InsertAfter = std::next(Inst->getIterator());
}
InsertReverseInsertPt(&*InsertAfter);
};
// Check for possible direct uses.

57
llvm/test/Transforms/ObjCARC/invoke-2.ll Normal file
View File

@ -0,0 +1,57 @@
; RUN: opt -mtriple x86_64-unknown-windows-msvc -objc-arc -o - %s | llvm-dis -o - - | FileCheck %s
target triple = "x86_64-unknown-windows-msvc"
declare i32 @__CxxFrameHandler3(...)
declare dllimport i8* @objc_msgSend(i8*, i8*, ...) local_unnamed_addr
declare dllimport i8* @objc_retain(i8* returned) local_unnamed_addr
declare dllimport void @objc_release(i8*) local_unnamed_addr
declare dllimport i8* @objc_retainAutoreleasedReturnValue(i8* returned) local_unnamed_addr
declare dllimport i8* @objc_begin_catch(i8*) local_unnamed_addr
declare dllimport void @objc_end_catch() local_unnamed_addr
@OBJC_METH_VAR_NAME_ = private unnamed_addr constant [2 x i8] c"m\00", align 1
@OBJC_SELECTOR_REFERENCES_ = private externally_initialized global i8* getelementptr inbounds ([2 x i8], [2 x i8]* @OBJC_METH_VAR_NAME_, i64 0, i64 0), section ".objc_selrefs$B", align 8
define void @f(i8* %i) local_unnamed_addr personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
entry:
%0 = tail call i8* @objc_retain(i8* %i)
%1 = load i8*, i8** @OBJC_SELECTOR_REFERENCES_, align 8, !invariant.load !0
%call = invoke i8* bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i8* (i8*, i8*)*)(i8* %0, i8* %1)
to label %invoke.cont unwind label %catch.dispatch, !clang.arc.no_objc_arc_exceptions !0
catch.dispatch: ; preds = %entry
%2 = catchswitch within none [label %catch] unwind to caller
invoke.cont: ; preds = %entry
%3 = tail call i8* @objc_retainAutoreleasedReturnValue(i8* %call)
tail call void @objc_release(i8* %3) #0, !clang.imprecise_release !0
br label %eh.cont
eh.cont: ; preds = %invoke.cont, %catch
tail call void @objc_release(i8* %0) #0, !clang.imprecise_release !0
ret void
catch: ; preds = %catch.dispatch
%4 = catchpad within %2 [i8* null, i32 0, i8* null]
%exn.adjusted = tail call i8* @objc_begin_catch(i8* undef)
tail call void @objc_end_catch(), !clang.arc.no_objc_arc_exceptions !0
br label %eh.cont
}
; CHECK-LABEL: @f
; CHECK-NOT: tail call i8* @objc_retain(i8* %i)
; CHECK: load i8*, i8** @OBJC_SELECTOR_REFERENCES_, align 8
; CHECK: eh.cont:
; CHECK-NOT: call void @objc_release(i8*
; CHECK: ret void
attributes #0 = { nounwind }
!0 = !{}