From b4ab549ae5558b9fd818a6268c32480b51fda9f6 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 21 Aug 2025 16:57:22 -0700 Subject: [PATCH] libio: Properly link in libio functions in static binaries commit 3020f72618e4f1d7338cd42b8bc7b2813e961b5a Author: Adhemerval Zanella Netto Date: Tue Dec 27 18:11:43 2022 -0300 libio: Remove the usage of __libc_IO_vtables added #define libio_static_fn_required(name) __asm (".globl " #name); to link in libio functions in static binaries. But there is no relocation in .globl _IO_file_open and "strip --strip-unneeded" will remove such unreferenced symbols which breaks static binaries. Redefine libio_static_fn_required to create a reference to the required function with static __typeof (name) *const name##_p __attribute__((used)) = name; This fixes BZ #33300. Signed-off-by: H.J. Lu Tested-by: Xi Ruoyao --- libio/Makefile | 9 +++++++++ libio/libioP.h | 3 ++- libio/tst-stdio-static.c | 28 ++++++++++++++++++++++++++++ 3 files changed, 39 insertions(+), 1 deletion(-) create mode 100644 libio/tst-stdio-static.c diff --git a/libio/Makefile b/libio/Makefile index f020f8ec4d..6ce669e103 100644 --- a/libio/Makefile +++ b/libio/Makefile @@ -130,6 +130,7 @@ tests = \ tst-sprintf-chk-ub \ tst-sprintf-ub \ tst-sscanf \ + tst-stdio-static \ tst-swscanf \ tst-ungetwc1 \ tst-ungetwc2 \ @@ -149,6 +150,8 @@ tests = \ tst_wscanf \ # tests +tests-static += tst-stdio-static + $(objpfx)tst-popen-fork: $(shared-thread-library) tests-internal = tst-vtables tst-vtables-interposed @@ -445,3 +448,9 @@ $(objpfx)tst-bz22415-mem.out: $(objpfx)tst-bz22415.out $(objpfx)tst-bz24228-mem.out: $(objpfx)tst-bz24228.out $(common-objpfx)malloc/mtrace $(objpfx)tst-bz24228.mtrace > $@; \ $(evaluate-test) + +# Test stdio.o with "strip --strip-unneeded". +$(objpfx)tst-stdio-static: $(objpfx)stdio-stripped.o + +$(objpfx)stdio-stripped.o: $(objpfx)stdio.o + $(STRIP) --strip-unneeded -o $@ $< diff --git a/libio/libioP.h b/libio/libioP.h index 1e3d28bb34..6508e46379 100644 --- a/libio/libioP.h +++ b/libio/libioP.h @@ -535,7 +535,8 @@ extern const struct _IO_jump_t __io_vtables[] attribute_hidden; #ifdef SHARED # define libio_static_fn_required(name) #else -# define libio_static_fn_required(name) __asm (".globl " #name); +# define libio_static_fn_required(name) \ + static __typeof (name) *const name##_p __attribute__((used)) = name; #endif extern int _IO_do_write (FILE *, const char *, size_t); diff --git a/libio/tst-stdio-static.c b/libio/tst-stdio-static.c new file mode 100644 index 0000000000..48c7f76e6e --- /dev/null +++ b/libio/tst-stdio-static.c @@ -0,0 +1,28 @@ +/* Test static stdio.o with "strip --strip-unneeded". + Copyright (C) 2025 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +/* NB: Call main directly to trigger BZ #33300. */ + +int +main (void) +{ + printf ("OK\n"); + return 0; +} -- 2.47.2