From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 28 Dec 2018 09:27:41 +0300 From: Alexander Turenko Subject: Re: [PATCH] cmake: workaround GCC 7.2 segfault on v?sn?printf Message-ID: <20181228062740.bf6yt2wtfxpdnn3d@tkn_work_nb> References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: To: Vladimir Davydov Cc: tarantool-patches@freelists.org List-ID: Fixed Ubuntu Artful: ``` diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake index b471b0c38..0d7bf6347 100644 --- a/cmake/compiler.cmake +++ b/cmake/compiler.cmake @@ -350,14 +350,14 @@ endif() # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83448 # It is important for the test case to be compiled w/o any extra -# flags and with -O2. Say, -Wall allows the case be compiled -# successfully on gcc-7.2.1. +# flags and with -O2. Say, -Wformat allows the case be compiled +# successfully on gcc-7.2. set(PREVIOUS_CMAKE_C_FLAGS ${CMAKE_C_FLAGS}) set(CMAKE_C_FLAGS "") set(CMAKE_REQUIRED_DEFINITIONS "") set(CMAKE_REQUIRED_INCLUDES "") set(CMAKE_REQUIRED_LIBRARIES "") -set(CMAKE_REQUIRED_FLAGS "-O2") +set(CMAKE_REQUIRED_FLAGS "-O2 -Wno-format") check_c_source_compiles(" char *a; ``` https://travis-ci.org/tarantool/tarantool/builds/472898526 WBR, Alexander Turenko. On Fri, Dec 28, 2018 at 07:48:54AM +0300, Alexander Turenko wrote: > GCC 7.2.1 fails like so on our codebase: > > /tarantool/src/lib/json/json.c: In function ‘json_token_snprint’: > /tarantool/src/lib/json/json.c:324:1: internal compiler error: Segmentation fault > json_token_snprint(char *buf, int size, const struct json_token *token, > ^~~~~~~~~~~~~~~~~~ > > The backtrace of cc1 is the following (failed to install compatible > debuginfo on Fedora 26, so ??s): > > #0 0x0000000000d0320c in get_source_location_for_substring(cpp_reader*, string_concat_db*, unsigned int, cpp_ttype, int, int, int, unsigned int*) () > #1 0x00000000005c0e79 in c_get_substring_location(substring_loc const&, unsigned int*) () > #2 0x00000000007f8418 in format_warning_va(substring_loc const&, source_range const*, char const*, int, char const*, __va_list_tag (*) [1]) () > #3 0x00000000007f838b in format_warning_at_substring(substring_loc const&, source_range const*, char const*, int, char const*, ...) () > #4 0x0000000000c72c2d in ?? () > #5 0x0000000000f6f308 in execute_one_pass(opt_pass*) () > #6 0x0000000000787da6 in ?? () > #7 0x00000000012ac338 in symbol_table::compile() () > #8 0x0000000000de650f in symbol_table::finalize_compilation_unit() () > #9 0x00000000012ee8df in ?? () > #10 0x0000000000d3ba84 in toplev::main(int, char**) () > #11 0x0000000000d3d35b in main () > > The issue in the GCC bugtracker: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83448 > > The idea of the commit is to check builtin snprintf with the code from > GCC test suite and disable all related builtins if the compiler is GCC > and the case fails. > > We also need to disable FORTIFY_SOURCES in the case, because it uses > v?sn?printf builtins directly. > --- > > no issue > https://github.com/tarantool/tarantool/tree/Totktonada/workaround-gcc-7.2-snprintf-segfault > > Be attentive: I pushed DO NOT MERGE commit upward the commit I send here > to enable full testing on the bugfix branch: [1] (hope it will pass). > The topmost commit should NOT be pushed to 2.1. > > [1]: https://travis-ci.org/tarantool/tarantool/builds/472881226 > > cmake/compiler.cmake | 43 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 43 insertions(+) > > diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake > index 4062d13ec..b471b0c38 100644 > --- a/cmake/compiler.cmake > +++ b/cmake/compiler.cmake > @@ -333,6 +333,8 @@ if (NOT HAVE_BUILTIN_CTZ OR NOT HAVE_BUILTIN_CTZLL) > HAVE_FFSL) > check_c_source_compiles("#include \n#include \nint main(void) { return ffsll(0UL); }" > HAVE_FFSLL) > + set(CMAKE_REQUIRED_FLAGS "") > + set(CMAKE_REQUIRED_DEFINITIONS "") > endif() > endif() > > @@ -343,3 +345,44 @@ else() > set(CMAKE_HOST_C_COMPILER ${CMAKE_C_COMPILER}) > set(CMAKE_HOST_CXX_COMPILER ${CMAKE_CXX_COMPILER}) > endif() > + > +# Check for broken __builtin_v?sn?printf() in gcc-7.2. > +# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83448 > + > +# It is important for the test case to be compiled w/o any extra > +# flags and with -O2. Say, -Wall allows the case be compiled > +# successfully on gcc-7.2.1. > +set(PREVIOUS_CMAKE_C_FLAGS ${CMAKE_C_FLAGS}) > +set(CMAKE_C_FLAGS "") > +set(CMAKE_REQUIRED_DEFINITIONS "") > +set(CMAKE_REQUIRED_INCLUDES "") > +set(CMAKE_REQUIRED_LIBRARIES "") > +set(CMAKE_REQUIRED_FLAGS "-O2") > + > +check_c_source_compiles(" > +char *a; > +int b; > + > +int > +main(void) > +{ > + for (;;) { > + if (b < 0) > + main(); > + __builtin_snprintf(a, b, \"%*s\", b, \"\"); > + } > + return 0; > +}" HAVE_BUILTIN_SNPRINTF) > + > +set(CMAKE_REQUIRED_FLAGS "") > +set(CMAKE_C_FLAGS ${PREVIOUS_CMAKE_C_FLAGS}) > + > +# /usr/include/stdio.h (bits/stdio2.h to be exact) uses builtin > +# gcc v?sn?printf functions when fortify source is enabled. > +if (CMAKE_COMPILER_IS_GNUCC AND NOT HAVE_BUILTIN_SNPRINTF) > + add_compile_flags("C;CXX" "-Wp,-U_FORTIFY_SOURCE") > + add_compile_flags("C;CXX" "-fno-builtin-sprintf") > + add_compile_flags("C;CXX" "-fno-builtin-snprintf") > + add_compile_flags("C;CXX" "-fno-builtin-vsnprintf") > + add_compile_flags("C;CXX" "-fno-builtin-vsprintf") > +endif() > -- > 2.20.1 >