[cfe-dev] [UBsan suppression] implicit-integer-sign-change

Roman Lebedev via cfe-dev cfe-dev at lists.llvm.org
Fri Jan 25 05:21:57 PST 2019


On Fri, Jan 25, 2019 at 4:07 PM Pascal Cremer via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
>
> I would like to suppress implicit-integer-sign-change warnings which
> encounter in
>
> boost/1_64_0/include/boost/iostreams/filter/gzip.hpp:674:16: runtime
> error: implicit conversion from type 'int' of value 139 (32-bit, signed)
> to type 'char' changed the value to -117 (8-bit, signed)
>      #0 0x7fed40b77bc2 in
> boost::iostreams::basic_gzip_compressor<std::allocator<char>
>  >::basic_gzip_compressor(boost::iostreams::gzip_params const&, long)

Can you please show the whole output, including "SUMMARY:
UndefinedBehaviorSanitizer: implicit-????" line?
(IIRC you need to also enable asan to get that line)

> I tried with this line in my suppressions file (which works great for
> other types of warnings)
>
> implicit-integer-sign-change:/path/to/boost/*
Assuming that you are actually seeing the implicit-integer-sign-change
issue, according to
https://github.com/llvm-mirror/compiler-rt/blob/dd358a8a7ce65eb3189740d99b6a450605947aab/test/ubsan/TestCases/ImplicitConversion/integer-sign-change-blacklist.c#L12
that should work.

I'm not sure, is that blacklist read at runtime or not, do you need to
recompile the code in order for it to be updated?

> However, I get at runtime:
>
> UndefinedBehaviorSanitizer: failed to parse suppressions
>
> I also reported this on SO a while ago:
>
> https://stackoverflow.com/questions/53466501/c-clang-ubsan-suppression-flag-name
>
> Any help would be much appreciated.
Roman.

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