[llvm-dev] ASan port for Myriad RTEMS

[Kostya Serebryany via llvm-dev]

On Fri, May 4, 2018 at 7:09 PM Walter Lee <waltl at google.com> wrote:

> On Fri, May 4, 2018 at 6:21 PM Kostya Serebryany <kcc at google.com> wrote:
>
> > On RAM...
>
> > You chose the 32-byte shadow granularity to reduce the RAM overhead,
> > but I am afraid this will actually increase it due to extra alignment
> requirements,
> > especially if an average allocation on your typical application is small.
>
>
> Good point.  I will run our test suite with 8-byte shadow granularity and
> do some measurements.
>

try 16 as well.
Depending on your typical code and default alignment, I would expect 8 or
16 to be the best.


>
> In general, the memory constraint hasn't been as big an issue as I
> initially thought.  The mitigating factor is that we are focused on unit
> tests as opposed to running the full blown application.
>
>
> > The pointers are 32-bit, right?
> > Given how RAM-constrained your environment is, maybe you should consider
> something more like HWASAN instead of ASAN.
> > https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
> > But you may not have enough address bits. :(
>
> Pointers are 32 bits.  Interesting idea, but I agree I don't think we have
> enough bits.  Even ignoring the sparsely used lower addresses, DDR + cache
> bit leaves us with only 2 bits.
>
> Thanks,
>
> Walter
>
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