^^^ gentle ping.
On 08/16/2018 02:28 PM, Mikhail Kashkarov wrote: > ^^ gentle ping. > > On 07/16/2018 07:16 PM, Mikhail Kashkarov wrote: >> Rebased and update patch (typos, add missing annotations), >> add ASan teststo verify string annotation. >> >> >> On 06/28/2018 11:09 AM, Mikhail Kashkarov wrote: >>> ^ gentle ping. >>> >>> >>> On 06/08/2018 05:54 PM, Mikhail Kashkarov wrote: >>>> Hello, >>>> >>>> I've updated patches for std::string sanitization and disabling CXX11 >>>> string SSO usage for correct sanitization. >>>> >>>> >> _M_destroy(_M_allocated_capacity); >>>> >>+ else >>>> >>+ __annotate_delete(); >>>> > >>>> >Do these calls definitely optimize away completely when not >>>> >sanitizing? Even for -O1, -Os and -Og? >>>> > >>>> >For std::vector annotation I used macros to add these >>>> annotations, so >>>> >there is no change to the generated code when annotations are >>>> >disabled. But it makes the code quite ugly. >>>> >>>> I've checked asm code for string-inst.o and it looks like this >>>> calls are >>>> optimized away, but there are some light changes after patch fir . >>>> >>>> > Right, I was wondering specifically about the <fstream> >>>> > instantiations. I could be wrong but I don't think anything in >>>> > <fstream> creates, destroys or modifies a std::basic_string. >>>> >>>> I was confused by reinterpret_cast's on strings in fstream.tcc, looks >>>> like this is not needed, you are right. >>>> >>>> >> // calling 4.0.x+ _S_create. >>>> >> __p->_M_set_sharable(); >>>> >>+#if _GLIBCXX_SANITIZER_ANNOTATE_STRING >>>> >>+ __p->_M_length = 0; >>>> >>+#endif >>>> > >>>> > Why is this needed? I think a comment explaining it would help >>>> (like >>>> > the one above explaining why calling _M_set_sharable() is >>>> needed). >>>> >>>> Checked current version without this change, looks like now it works, >>>> reverted. >>>> >>>> Short summary: >>>> The reason for changing strings layout under sanitization is to >>>> place string >>>> char buffer on heap for correct aligning in 32-bit environments, >>>> both pre-CXX11 and CXX11 strings ABI. >>>> >>>> | Sanitize string | string type | ABI is changed? | 32-bit | 64-bit | >>>> |-----------------+-------------+-----------------+--------+--------| >>>> | FULL | SSO-string | yes | + | + | >>>> | | COW-string | yes | + | + | >>>> |-----------------+-------------+-----------------+--------+--------| >>>> | PARTIAL | SSO-string | no | -+(*) | + | >>>> | | COW-string | no | - | + | >>>> *only longs strings are sanitized for 32-bit >>>> >>>> Some functions with new define looks a bit messy without changing >>>> internal >>>> functions(operator=), I'm also not sure if disabling string SSO >>>> usage define >>>> should also affects other parts that relies on basic_string class size >>>> (checks >>>> with static_assert in exceptions/shim-facets). >>>> >>>> >>>> Any thoughts? >>>> >>>> On 05/29/2018 06:55 PM, Jonathan Wakely wrote: >>>>> On 29/05/18 18:18 +0300, Kashkarov Mikhail wrote: >>>>>> Jonathan Wakely <jwak...@redhat.com> writes: >>>>>>>> --- a/libstdc++-v3/include/bits/fstream.tcc >>>>>>>> +++ b/libstdc++-v3/include/bits/fstream.tcc >>>>>>>> @@ -1081,6 +1081,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION >>>>>>>> >>>>>>>> // Inhibit implicit instantiations for required >>>>>>>> instantiations, >>>>>>>> // which are defined via explicit instantiations elsewhere. >>>>>>>> +#if !_GLIBCXX_SANITIZE_STRING >>>>>>>> #if _GLIBCXX_EXTERN_TEMPLATE >>>>>>>> extern template class basic_filebuf<char>; >>>>>>>> extern template class basic_ifstream<char>; >>>>>>>> @@ -1094,6 +1095,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION >>>>>>>> extern template class basic_fstream<wchar_t>; >>>>>>>> #endif >>>>>>>> #endif >>>>>>>> +#endif // !_GLIBCXX_SANITIZE_STRING >>>>>>> Why do we need to disable these explicit instantiation >>>>>>> declarations? >>>>>>> Are they affected by the std::string layout changes? Is that just >>>>>>> because of the constructors taking std::string, or something else? >>>>>> Libstdc++ build is not sanitized, so macroses that requires >>>>>> AddressSanitizer support will not applied and these templates >>>>>> will be >>>>>> instantate without support for ASan annotations. >>>>> Right, I was wondering specifically about the <fstream> >>>>> instantiations. I could be wrong but I don't think anything in >>>>> <fstream> creates, destroys or modifies a std::basic_string. >>>>> >>>>> >>>>> >>>>> >>>>> >> > -- Best regards, Kashkarov Mikhail Samsung R&D Institute Russia
