Some more context: It seems like we already need to do that when building the CFG: for the lifetime extended object we must not emit the destructor at the end of the full expression, which we currently do.
On Mon, Jul 28, 2014 at 3:03 PM, Manuel Klimek <[email protected]> wrote: > On Mon, Jul 7, 2014 at 10:15 PM, Jordan Rose <[email protected]> > wrote: > >> Ah...then I'm glad we added the assertion. :-) Lifetime-extended >> temporaries aren't quite implemented correctly yet, but we should probably >> be removing or not even adding the state when the temporary is >> lifetime-extended. >> >> Unfortunately I don't have this paged in, but there's logic in processing >> auto destructors to handle this, and a bug ( >> http://llvm.org/bugs/show_bug.cgi?id=19539) about how it's wrong. >> > > Ok, I dug into this a bit, and if I'm not missing something I think it's > not possible to switch this off without implementing lifetime-extended > temporaries correctly (or at least a similarly sized implementation effort): > The only link between the MaterializeTempooraryExpr (which has the > information whether the lifetime was extended) and the CXXBindTemporaryExpr > is the underlying object storage. I looked into CodeGen, and if I > understand it correctly, it looks like it basically stores for the > destination whether the destructor was already handled (for example from > the MaterializeTemporary flow). To get that information, I'd guess we need > to do something similar in the static analyzer. > > I hope that my analysis is wrong and you tell me a better way to fix this > :) > > Thanks! > /Manuel > > >> >> Jordan >> >> >> On Jul 7, 2014, at 13:13 , Manuel Klimek <[email protected]> wrote: >> >> Sigh. That triggers in Analysis/dtor.cpp for this CXXBindTemporaryExpr: >> CXXBindTemporaryExpr 0x3c195d8 'class >> LifetimeExtension::SaveOnVirtualDestruct' (CXXTemporary 0x3c195d0) >> `-CXXTemporaryObjectExpr 0x3c19590 'class >> LifetimeExtension::SaveOnVirtualDestruct' 'void (void)' >> >> I assume something fishy is going on for lifetime extended temporaries... >> >> >> On Mon, Jul 7, 2014 at 8:38 PM, Jordan Rose <[email protected]> >> wrote: >> >>> >>> On Jul 7, 2014, at 11:37 , Manuel Klimek <[email protected]> wrote: >>> >>> On Mon, Jul 7, 2014 at 8:05 PM, Jordan Rose <[email protected]> >>> wrote: >>> >>>> >>>> On Jul 7, 2014, at 10:50 , Manuel Klimek <[email protected]> wrote: >>>> >>>> On Mon, Jul 7, 2014 at 7:42 PM, Jordan Rose <[email protected]> >>>> wrote: >>>> >>>>> >>>>> On Jul 7, 2014, at 10:41 , Manuel Klimek <[email protected]> wrote: >>>>> >>>>> On Mon, Jul 7, 2014 at 7:38 PM, Jordan Rose <[email protected]> >>>>> wrote: >>>>> >>>>>> >>>>>> On Jul 7, 2014, at 10:37 , Manuel Klimek <[email protected]> wrote: >>>>>> >>>>>> On Mon, Jul 7, 2014 at 7:29 PM, Jordan Rose <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> On Jul 7, 2014, at 10:28 , Manuel Klimek <[email protected]> wrote: >>>>>>> >>>>>>> On Mon, Jul 7, 2014 at 6:48 PM, Jordan Rose <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>>>> Can you add an assertion at the end of a block that there are no >>>>>>>> outstanding temporary destructors in the current stack frame? That >>>>>>>> seems >>>>>>>> useful. >>>>>>>> >>>>>>> >>>>>>> Do you mean at the end of a VisitBlockDecl? >>>>>>> >>>>>>> >>>>>>> No, during the path-sensitive run, so handleBlockExit. >>>>>>> >>>>>> >>>>>> So you mean at the end of a CFG block? But here we might have >>>>>> outstanding temporary dtors open (?) >>>>>> >>>>>> >>>>>> Oops, right. Was thinking too much in terms of AST structure. How >>>>>> about at the end of a function (inlined or not)? >>>>>> >>>>> >>>>> Could we say every time we transition from a block with a temp dtor >>>>> terminator to a block that does not have a temp dtor terminator (or an >>>>> unconditional terminator) we check? >>>>> >>>>> >>>>> That sounds correct, but misses the case where we built the CFG wrong >>>>> (forgetting to add the branch in the correct place and thus never getting >>>>> to the temp dtor block at all). >>>>> >>>> >>>> Makes sense. Do you have a hint where the right place on function exit >>>> to check it would be? :) >>>> >>>> >>>> *checks* ExprEngine::processEndOfFunction. >>>> >>> >>> Hm, so we'll need to adjust the data structure to be indexed by stack >>> frame somehow (use a map) instead of the pair<expr, stack-frame>? >>> >>> >>> Eh, since it's an assertion I'd be fine with just iterating over it in a >>> helper function. Or better, using std::find_if (if it has proper begin/end >>> members). >>> >> >> >> >
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