From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp52.i.mail.ru (smtp52.i.mail.ru [94.100.177.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 62FF1469711 for ; Fri, 20 Nov 2020 05:23:58 +0300 (MSK) From: Artem Starshov Date: Fri, 20 Nov 2020 05:23:50 +0300 Message-Id: <848eefec50be4135d9ae3a50f3816d7e334fbc02.1605828734.git.artemreyt@tarantool.org> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH 2/2] bitset: fix GCC 10 build List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Turenko Cc: tarantool-patches@dev.tarantool.org GCC 10 reports: "warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]" It's false positive. In order to fix build i tried to add ignoring gcc -Wstringop-overflow via preprocessor directive `pragma GCC ignored`. But it doesn't work, so added -Wnostringop-overflow flag in complier.cmake for gcc version equal or greather 10. Explaining of false positive: The problem is: In file included from /root/ttar/src/lib/bitset/bitset.h:45, from /root/ttar/src/lib/bitset/bitset.c:32: In function ‘bit_set’, inlined from ‘tt_bitset_set’ at /root/ttar/src/lib/bitset/bitset.c:112:14: /root/ttar/src/lib/bit/bit.h:230:15: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=] 230 | ldata[chunk] |= (1UL << offset); | ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~ I made a research and found out that if to explicitly init bitset->realloc = realloc than a warning is still triggers, but if not to call rb_tree functions (tt_bitset_pages_search and tt_bitset_pages_insert) it's ok. But these functions don't allocate or free a memory, so they can't influence on memory region which `page` variable points to. Part-of #4966 --- cmake/compiler.cmake | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake index db2ae6227..5db636812 100644 --- a/cmake/compiler.cmake +++ b/cmake/compiler.cmake @@ -430,3 +430,17 @@ else() set(CMAKE_HOST_C_COMPILER ${CMAKE_C_COMPILER}) set(CMAKE_HOST_CXX_COMPILER ${CMAKE_CXX_COMPILER}) endif() + +if (CMAKE_COMPILER_IS_GNUCC AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10) +# In file included from src/lib/bitset/bitset.h:45, +# from src/lib/bitset/bitset.c:32: +# In function ‘bit_set’, +# inlined from ‘tt_bitset_set’ at src/lib/bitset/bitset.c:111:14: +# src/lib/bit/bit.h:230:15: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=] +# 230 | ldata[chunk] |= (1UL << offset); +# | ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~ +# +# false positive for gcc version 10 +# macro 'GCC diagnostic ignored "-Wstringop-overflow"' doesn't help + add_compile_flags("C" "-Wno-stringop-overflow") +endif() -- 2.28.0