DavidSpickett added inline comments.
================
Comment at: lldb/tools/intel-features/intel-mpx/cli-wrapper-mpxtable.cpp:66
- if ((lbound == one_cmpl64 || one_cmpl32) && ubound == 0) {
result.Printf("Null bounds on map: pointer value = 0x%" PRIu64 "\n",
value);
----------------
hawkinsw wrote:
> DavidSpickett wrote:
> > hawkinsw wrote:
> > > According to
> > > https://en.cppreference.com/w/cpp/language/operator_precedence, I would
> > > read the left operand of the `&&` as
> > >
> > > 1. The `==` has higher precedence than `||` so, `b = (lbound ==
> > > one_compl64)`
> > > 2. `b || one_cmpl32`
> > >
> > > which does not seem like what the original author intended. I absolutely
> > > think that the fix is correct, but I just wanted to get everyone's
> > > feedback on whether this seems like more than just a "suspicious bitwise
> > > expression" (and more like a "mistaken bitwise expression").
> > >
> > > All that said, I could be completely, 100% wrong. And, if I am, feel free
> > > to ignore me!
> > The corrected code also makes sense given that MPX is some kind of memory
> > protection across ranges.
> >
> > If `((lbound == one_cmpl64 || lbound == one_cmpl32) && ubound == 0)` is
> > true then upper bound < lower bound making an invalid range. Which is what
> > I'd expect for some default/uninitialised state (especially if zero size
> > ranges are allowed, so upper == 0 and lower == 0 couldn't be used).
> @DavidSpickett I think that you and I are saying the same thing, right? We
> are both saying that the corrected code looks much "better" than the original?
>
> Will
> We are both saying that the corrected code looks much "better" than the
> original?
Yes.
> whether this seems like more than just a "suspicious bitwise expression" (and
> more like a "mistaken bitwise expression").
Definitely a mistake that needs correcting.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131312/new/
https://reviews.llvm.org/D131312
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