[PATCH] D66651: Annotate return values of allocation functions with dereferenceable_or_null

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 marked an inline comment as done.
xbolva00 added inline comments.


================
Comment at: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp:4200
+                          Call.getContext(), Op1C->getZExtValue()));
+  } else if (isCallocLikeFn(&Call, TLI) && Op0C && Op1C) {
+    bool Overflow;
----------------
xbolva00 wrote:
> xbolva00 wrote:
> > xbolva00 wrote:
> > > jdoerfert wrote:
> > > > What if one is NULL but the other not? Will `getWithDereferenceableOrNullBytes(0)` do the right thing?
> > > Maybe isNullValue confused you. isNullValue means just CstInt->getValue() == 0.
> > > 
> > > if Op0C is NULL -> no calloc annotation
> > > if Op1C is NULL -> no calloc annotation
> > > 
> > > if Op0C is '0' -> no annotation; see
> > > if ((Op0C && Op0C->isNullValue()) || (Op1C && Op1C->isNullValue()))
> > >     return;
> > > 
> > > Same for Op1C.
> > I will add a comment like
> > 
> >   // Bail out if the allocation size is zero.
> >   if ((Op0C && Op0C->isNullValue()) || (Op1C && Op1C->isNullValue()))
> >     return;
> Aha, I know what do you mean.
> 
> Hmm, it could work for calloc case - I will look on it.
eh, no :D

calloc(1, unknown_var) - We can do nothing in this case ..


Repository:
  rL LLVM

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  https://reviews.llvm.org/D66651/new/

https://reviews.llvm.org/D66651