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From: "i at maskray dot me" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libgcc/99759] morestack.S should support .init_array.0 besides .ctors.65535 Date: Thu, 12 Aug 2021 01:52:58 +0000 [thread overview] Message-ID: <bug-99759-4-4td4nX8i1S@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-99759-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99759 --- Comment #3 from Fangrui Song <i at maskray dot me> --- (In reply to Alan Modra from comment #2) > > this means the ctors.65535 will come last. > Nope, it will come first. And since DT_INIT_ARRAY pointers are executed in > the order they appear in the array, it will be one of the first to run. > .init_array and .ctors sorting is complicated. ld.bfd will sort > .init_array.0 (highest priority .init_array section) and .ctors.65535 > (highest priority .ctors section) together. > > I assume this comment: > > The input section description is quite close but does not sort .init_array.* and .ctors.* with the same priority together. > is referring to lld. `KEEP (*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)))` The syntax is ambiguous. I can read it this way: place .init_array.* before .ctors.* , but the behavior is (the ideal way): .init_array 0x0000000000402ff9 0x7 [!provide] PROVIDE (__init_array_start = .) *(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)) .init_array.5 0x0000000000402ff9 0x1 a.o .ctors.65529 0x0000000000402ffa 0x1 a.o .init_array.7 0x0000000000402ffb 0x1 a.o .ctors.65435 0x0000000000402ffc 0x1 a.o .init_array.100 0x0000000000402ffd 0x1 a.o *(.init_array EXCLUDE_FILE(*crtend?.o *crtend.o *crtbegin?.o *crtbegin.o) .ctors) .init_array 0x0000000000402ffe 0x1 a.o .ctors 0x0000000000402fff 0x1 a.o [!provide] PROVIDE (__init_array_end = .) It is unclear that contiguous SORT_BY_INIT_PRIORITY are sorted as a unit. > > I don't see any issue here really in the end because GCC will produce init_array most of the time. > So the issue really is that lld doesn't support mixing of .ctors.* and > .init_array.*. Yes. > It might be nice for libgcc to use .init_array.0 here instead of > .ctors.65536 whenever gcc will use .init_array in compiled code. Yes. This is the only place I know where modern Linux distrubtions is still using .ctors* in .o files.
next prev parent reply other threads:[~2021-08-12 1:52 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-25 3:16 [Bug libgcc/99759] New: " i at maskray dot me 2021-04-05 0:26 ` [Bug libgcc/99759] " pinskia at gcc dot gnu.org 2021-08-12 0:39 ` amodra at gmail dot com 2021-08-12 1:52 ` i at maskray dot me [this message] 2021-10-08 19:09 ` i at maskray dot me
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