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);
----------------
DavidSpickett wrote:
> 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.
(I think "suspicious bitwise expression" is what the static analyser would call
it just because it can't be 100% sure it is wrong)
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131312/new/
https://reviews.llvm.org/D131312
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