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Re: Report on the bounded pointers work
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Yury Gribov <y dot gribov at samsung dot com>
- Cc: law at redhat dot com, fweimer at redhat dot com, gcc <gcc at gcc dot gnu dot org>, Viacheslav Garbuzov <v dot garbuzov at samsung dot com>, Evgeny Gavrin <e dot gavrin at samsung dot com>
- Date: Tue, 05 Nov 2013 13:26:02 -0500
- Subject: Re: Report on the bounded pointers work
- Authentication-results: sourceware.org; auth=none
- References: <5278C46C dot 7090802 at samsung dot com>
Yury Gribov <y.gribov@samsung.com> writes:
>[...]
>> [mudflap] never reached a point where interoperability across objects with
> and without mudflap instrumentation worked
>
> Could you add more details? E.g. I don't see how mudflap
> interoperability is different from AdressSanitizer which seems to be
> state of the art.
My sense is that asan and mudflap are comparable with respect to
support of interoperation between instrumented and uninstrumented
code. The trick is how to handle pointers arriving from the latter.
libmudflap handled this issue in two ways: by attempting to intercept
all heap allocations from libraries (at the glibc/dlsym level), and by
heuristics for recognizing addresses that might have come from
unintercepted static/auto allocations. The former is tricky and was
an uphill battle trying to catch everything, so in practice heuristics
were almost always necessary.
(There are of course many differences. They have different tradeoffs
as to speed versus memory-consumption - asan is hard-coded in the
opposite direction than libmudflap's (configurable) default. asan's
multi-threading support may be superior. mudflap's tuning/features
were not completed. asan sports more recent developers.)
- FChE