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From: "i at maskray dot me" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/110729] New: -fpatchable-function-entries:
 __patchable_function_entries has wrong sh_link
Date: Wed, 19 Jul 2023 06:20:39 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110729

            Bug ID: 110729
           Summary: -fpatchable-function-entries:
                    __patchable_function_entries has wrong sh_link
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: i at maskray dot me
  Target Milestone: ---

Noticed by Ziwei Mao.

% cat a.c
void f() {}
void g() {}
void h() {}
% gcc -ffunction-sections -fpatchable-function-entry=3D2 -c a.c
% gcc -ffunction-sections -fpatchable-function-entry=3D2 -S a.c

a.o has .text.f, .text.g, and .text.h, but just one
__patchable_function_entries section.

% grep __patchable_function_entries a.s
        .section        __patchable_function_entries,"awo",@progbits,f
        .section        __patchable_function_entries,"awo",@progbits,f
        .section        __patchable_function_entries,"awo",@progbits,f

I think the second and the third __patchable_function_entries should refere=
nce
g and h, respectively. Otherwise, if f is discarded by ld --gc-sections, the
whole __patchable_function_entries (also used by g and h) will be discarded.
(Also, if g is discarded, its __patchable_function_entries fragment may be
retained if f is retained.)=