Valgrind: Conditional jump or move depends on uninitialised value

Bonjour à tous,

Je me tourne vers vous parce que je suis devant un mur que je n'arrive pas à franchir...
Je suis entrain de passer mon programme à valgrind pour virer toutes les erreurs/fuites mémoires.


Je n'arrive pas à corriger un "Conditional jump..."

Code:

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==11599== Thread 8: ==11599== Conditional jump or move depends on uninitialised value(s) ==11599== at 0x8F39903: Pcm::linear2alaw(short) (pcm.cpp:17) ==11599== by 0x8F38B8A: AudioUtils::convertToAlaw(AudioStream&) (audioutils.cpp:32) ==11599== by 0x8F38D30: AudioUtils::convertAndResample(AudioStream&, unsigned long const&, double const&, double const&, unsigned int const&) (audioutils.cpp:17) ==11599== by 0x8F46337: SynthesisSession::handleRead(boost::system::error_code const&, unsigned long) (synthesissession.cpp:144) ==11599== by 0x8F5154D: operator() (mem_fn_template.hpp:280) ==11599== by 0x8F5154D: operator()<boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::rrlist2<const boost::system::error_code&, long unsigned int const&> > (bind.hpp:398) ==11599== by 0x8F5154D: operator()<const boost::system::error_code&, long unsigned int const&> (bind.hpp:1318) ==11599== by 0x8F5154D: operator() (bind_handler.hpp:164) ==11599== by 0x8F5154D: asio_handler_invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int> > (handler_invoke_hook.hpp:69) ==11599== by 0x8F5154D: invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int>, boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> > > (handler_invoke_helpers.hpp:37) ==11599== by 0x8F5154D: asio_handler_invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int>, boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int> (bind_handler.hpp:207) ==11599== by 0x8F5154D: invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int>, boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int> > (handler_invoke_helpers.hpp:37) ==11599== by 0x8F5154D: dispatch<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int>, std::allocator<void> > (io_object_executor.hpp:119) ==11599== by 0x8F5154D: dispatch<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int>, std::allocator<void> > (io_object_executor.hpp:108) ==11599== by 0x8F5154D: complete<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, const boost::system::error_code&, long unsigned int>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::system::error_code, long unsigned int> > (handler_work.hpp:72) ==11599== by 0x8F5154D: boost::asio::detail::reactive_socket_recv_op<boost::asio::mutable_buffers_1, boost::_bi::bind_t<void, boost::_mfi::mf2<void, SynthesisSession, boost::system::error_code const&, unsigned long>, boost::_bi::list3<boost::_bi::value<SynthesisSession*>, boost::arg<1> (*)(), boost::arg<2> (*)()> >, boost::asio::detail::io_object_executor<boost::asio::executor> >::do_complete(void*, boost::asio::detail::scheduler_operation*, boost::system::error_code const&, unsigned long) (reactive_socket_recv_op.hpp:123) ==11599== by 0x8F49565: complete (scheduler_operation.hpp:40) ==11599== by 0x8F49565: do_complete (epoll_reactor.ipp:776) ==11599== by 0x8F49565: boost::asio::detail::epoll_reactor::descriptor_state::do_complete(void*, boost::asio::detail::scheduler_operation*, boost::system::error_code const&, unsigned long) (epoll_reactor.ipp:766) ==11599== by 0x8F3C4CA: complete (scheduler_operation.hpp:40) ==11599== by 0x8F3C4CA: do_run_one (scheduler.ipp:447) ==11599== by 0x8F3C4CA: boost::asio::detail::scheduler::run(boost::system::error_code&) (scheduler.ipp:200) ==11599== by 0x8F4308D: boost::asio::io_context::run() (io_context.ipp:63) ==11599== by 0x97F1346: thread_proxy (in /usr/local/lib/libboost_thread.so.1.72.0) ==11599== by 0x67D6EA4: start_thread (in /usr/lib64/libpthread-2.17.so) ==11599== by 0x6DEB9FC: clone (in /usr/lib64/libc-2.17.so)

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Le code en question est le suivant :

Code:

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//---------------------------------- std::uint8_t Pcm::linear2alaw(std::int16_t pcmVal) //---------------------------------- { std::int16_t mask, seg; std::uint8_t aval; pcmVal = pcmVal >> 3; if (pcmVal >= 0) { mask = 0xD5; // Sign (7th) bit = 1 } else { mask = 0x55; // Sign bit = 0 pcmVal = -pcmVal - 1; } // Convert the scaled magnitude to segment number seg = search(pcmVal, seg_aend, 8); // Combine the sign, segment, and quantization bits if (seg >= 8) return (std::uint8_t)(0x7F ^ mask); // Out of range, return maximum value else { aval = (std::uint8_t) seg << SEG_SHIFT; if (seg < 2) aval |= (pcmVal >> 1) & QUANT_MASK; else aval |= (pcmVal >> seg) & QUANT_MASK; return (aval ^ mask); } } //---------------------------------- std::int16_t Pcm::search(std::int16_t pcmVal, std::int16_t *table, std::int16_t size) //---------------------------------- { std::int16_t i; for (i = 0; i < size; i++) { if (pcmVal <= *table++) break; } return i; }

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L'erreur est sur la ligne que j'ai mis en gras à savoir (if (pcmVal >= 0).
Est-ce que vous auriez une idée de pourquoi cette erreur alors qu'à la ligne au dessus je n'ai aucune erreur...

Merci d'avance

Valgrind montre à quel moment une variable qui dépend d'une valeur non initialisée à des conséquences sur le flux du code, mais pas forcément quelle est la variable véritablement non initialisée. C’est-à-dire que le paramètre pcmVal provient d'une variable non initialisée (il faut remonter plus haut), mais que cela n'a de conséquence que sur le if.

Merci pour ton explication. Je ne voyais pas du tout la chose comme ça :)