Date: Tue, 4 Jun 2024 09:29:41 -0700 From: John Baldwin <jhb@FreeBSD.org> To: Lorenzo Salvadore <developer@lorenzosalvadore.it>, Konstantin Belousov <kostikbel@gmail.com> Cc: Zhenlei Huang <zlei@freebsd.org>, FreeBSD Current <current@freebsd.org> Subject: Re: gcc behavior of init priority of .ctors and .dtors section Message-ID: <dacbf6a4-322d-4dfc-bfce-282314c4cd7a@FreeBSD.org> In-Reply-To: <vsV7JfyoYOL7sBIY2z5Dg-2829ksASYTol-33RK76f5_L5RU9hEzogscSf1LK_RO3gtjZ6CyCyl3AMe-c9Dppdk0_kwN9rC0fSyi34YNl_0=@lorenzosalvadore.it> References: <3ECF8C28-D2D9-4212-B025-3EC64E46BADC@FreeBSD.org> <ZkZP3SWpe61etZOc@kib.kiev.ua> <vsV7JfyoYOL7sBIY2z5Dg-2829ksASYTol-33RK76f5_L5RU9hEzogscSf1LK_RO3gtjZ6CyCyl3AMe-c9Dppdk0_kwN9rC0fSyi34YNl_0=@lorenzosalvadore.it>
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On 5/16/24 4:05 PM, Lorenzo Salvadore wrote: > On Thursday, May 16th, 2024 at 20:26, Konstantin Belousov <kostikbel@gmail.com> wrote: >>> gcc13 from ports >>> `# gcc ctors.c && ./a.out init 1 init 2 init 5 init 4 init 3 main fini 3 fini 4 fini 5 fini 2 fini 1` >>> >>> The above order is not expected. I think clang's one is correct. >>> >>> Further hacking with readelf shows that clang produces the right order of >>> section .rela.ctors but gcc does not. >>> >>> ``` >>> # clang -fno-use-init-array -c ctors.c && readelf -r ctors.o | grep 'Relocation section with addend (.rela.ctors)' -A5 > clang.txt >>> # gcc -c ctors.c && readelf -r ctors.o | grep 'Relocation section with addend (.rela.ctors)' -A5 > gcc.txt >>> # diff clang.txt gcc.txt >>> 3,5c3,5 >>> < 000000000000 000800000001 R_X86_64_64 0000000000000060 init_65535_2 + 0 >>> < 000000000008 000700000001 R_X86_64_64 0000000000000040 init + 0 >>> < 000000000010 000600000001 R_X86_64_64 0000000000000020 init_65535 + 0 >>> --- >>> >>>> 000000000000 000600000001 R_X86_64_64 0000000000000011 init_65535 + 0 >>>> 000000000008 000700000001 R_X86_64_64 0000000000000022 init + 0 >>>> 000000000010 000800000001 R_X86_64_64 0000000000000033 init_65535_2 + 0 >>>> ``` >>> >>> The above show clearly gcc produces the wrong order of section `.rela.ctors`. >>> >>> Is that expected behavior ? >>> >>> I have not tried Linux version of gcc. >> >> Note that init array vs. init function behavior is encoded by a note added >> by crt1.o. I suspect that the problem is that gcc port is built without >> --enable-initfini-array configure option. > > Indeed, support for .init_array and .fini_array has been added to the GCC ports > but is present in the *-devel ports only for now. I will > soon proceed to enable it for the GCC standard ports too. lang/gcc14 is soon > to be added to the ports tree and will have it since the beginning. > > If this is indeed the issue, switching to a -devel GCC port should fix it. FWIW, the devel/freebsd-gcc* ports have passed this flag to GCC's configure for a long time (since we made the switch in clang). -- John Baldwin
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