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e82aab227b
For instance on x86_64 with gcc 12.1.1 andwith fstack-protector
enabled the empty function still generates a stack protector code
sequence:
0000000000000000 <_dl_relocate_static_pie>:
0: 48 83 ec 18 sub $0x18,%rsp
4: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax
b: 00 00
d: 48 89 44 24 08 mov %rax,0x8(%rsp)
12: 31 c0 xor %eax,%eax
14: 48 8b 44 24 08 mov 0x8(%rsp),%rax
19: 64 48 2b 04 25 28 00 sub %fs:0x28,%rax
20: 00 00
22: 75 05 jne 29 <_dl_relocate_static_pie+0x29>
24: 48 83 c4 18 add $0x18,%rsp
28: c3 ret
29: e8 00 00 00 00 call 2e <_dl_relocate_static_pie+0x2e>
And since the function is called prior thread pointer setup, it
triggers a invalid memory access (this is shown with the failure
of elf/tst-tls1-static-non-pie).
Although it might characterizes as compiler issue or missed
optimization, to be safe also disables stack protector on
static-reloc object.
Checked on x86_64-linux-gnu and sparc64-linux-gnu.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
204 lines
7.5 KiB
Makefile
204 lines
7.5 KiB
Makefile
# Makefile for csu code for GNU C library.
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# Copyright (C) 1995-2022 Free Software Foundation, Inc.
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# This file is part of the GNU C Library.
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# The GNU C Library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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# The GNU C Library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public
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# License along with the GNU C Library; if not, see
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# <https://www.gnu.org/licenses/>.
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# This directory contains the C startup code (that which calls main). This
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# consists of the startfile, built from start.c and installed as crt0.o
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# (traditionally) or crt1.o (for ELF). In ELF we also install crti.o and
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# crtn.o, special "initializer" and "finalizer" files used in the link
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# to make the .init and .fini sections work right.
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subdir := csu
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include ../Makeconfig
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routines = init-first libc-start $(libc-init) sysdep version check_fds \
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libc-tls dso_handle
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aux = errno
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elide-routines.os = libc-tls
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csu-dummies = $(filter-out $(start-installed-name),crt1.o Mcrt1.o)
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extra-objs = start.o \
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$(start-installed-name) g$(start-installed-name) $(csu-dummies) \
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S$(start-installed-name)
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omit-deps = $(patsubst %.o,%,$(start-installed-name) g$(start-installed-name) \
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b$(start-installed-name) $(csu-dummies) \
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S$(start-installed-name) \
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r$(start-installed-name) \
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gr$(start-installed-name))
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install-lib = $(start-installed-name) g$(start-installed-name) $(csu-dummies)
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# No tests are allowed in the csu/ subdirectory because the startup
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# code is compiled with special flags.
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tests =
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# static-reloc.os is a dummy object not actually used for anything. It is
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# linked into crt1.o nevertheless, which in turn is statically linked into
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# applications, so that build flags matter.
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# See <https://sourceware.org/ml/libc-alpha/2018-07/msg00101.html>.
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#
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# The function is called prior the thread pointer setup, and if stack
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# protector is enabled the compiler might still generate the stack check
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# (which requires the thread pointer correctly set).
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extra-no-ssp = static-reloc
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# libc-start.os is safe to be built with stack protector since
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# __libc_start_main is called after stack canary setup is done.
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ssp-safe.os = libc-start
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CFLAGS-.o += $(call elide-stack-protector,.o,$(routines) $(extra-no-ssp))
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CFLAGS-.op += $(call elide-stack-protector,.op,$(routines) $(extra-no-ssp))
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CFLAGS-.oS += $(call elide-stack-protector,.oS,$(routines) $(extra-no-ssp))
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CFLAGS-.os += $(call elide-stack-protector,.os,$(filter-out \
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$(ssp-safe.os), \
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$(routines) $(extra-no-ssp)))
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ifeq (yes,$(build-shared))
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extra-objs += S$(start-installed-name) gmon-start.os
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ifneq ($(start-installed-name),$(static-start-installed-name))
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extra-objs += gmon-start.o
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endif
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install-lib += S$(start-installed-name)
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generated += start.os
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else
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extra-objs += gmon-start.o
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endif
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ifeq (yes,$(enable-static-pie))
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extra-objs += r$(start-installed-name) gr$(start-installed-name)
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install-lib += r$(start-installed-name) gr$(start-installed-name)
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endif
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ifneq ($(start-installed-name),$(static-start-installed-name))
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extra-objs += $(static-start-installed-name) g$(static-start-installed-name)
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omit-deps += $(patsubst %.o,%,$(static-start-installed-name) \
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g$(static-start-installed-name))
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install-lib += $(static-start-installed-name) g$(static-start-installed-name)
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ifeq (yes,$(enable-static-pie))
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extra-objs += r$(static-start-installed-name) gr$(static-start-installed-name)
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omit-deps += $(patsubst %.o,%,r$(static-start-installed-name) \
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gr$(static-start-installed-name))
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install-lib += r$(static-start-installed-name) gr$(static-start-installed-name)
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endif
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endif
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before-compile += $(objpfx)abi-tag.h
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generated += abi-tag.h
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# Put it here to generate it earlier.
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gen-as-const-headers += rtld-sizes.sym
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# These are the special initializer/finalizer files. They are always the
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# first and last file in the link. crti.o ... crtn.o define the global
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# "functions" _init and _fini to run the .init and .fini sections.
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crtstuff = crti crtn
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install-lib += $(crtstuff:=.o)
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extra-objs += $(crtstuff:=.o)
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ifneq ($(multidir),.)
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multilib-extra-objs = $(addprefix $(multidir)/, $(install-lib))
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extra-objs += $(multilib-extra-objs)
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endif
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extra-objs += abi-note.o init.o static-reloc.o
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ifeq (yes,$(build-shared))
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extra-objs += static-reloc.os
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endif
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asm-CPPFLAGS += -I$(objpfx).
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# Enable unwinding so backtrace unwinds to __libc_start_main
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CFLAGS-libc-start.c += -funwind-tables
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include ../Rules
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# Make these in the lib pass so they're available in time to link things with.
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subdir_lib: $(extra-objs:%=$(objpfx)%)
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define link-relocatable
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$(CC) -nostdlib -nostartfiles -r -o $@ $^
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endef
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ifndef start-installed-name-rule
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# We link the ELF startfile along with a SHT_NOTE section indicating
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# the kernel ABI the binaries linked with this library will require.
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$(objpfx)$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
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$(objpfx)init.o $(objpfx)static-reloc.o
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$(link-relocatable)
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$(objpfx)r$(start-installed-name): $(objpfx)start.o $(objpfx)abi-note.o \
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$(objpfx)init.o
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$(link-relocatable)
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$(objpfx)S$(start-installed-name): $(objpfx)start.os $(objpfx)abi-note.o \
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$(objpfx)init.o
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$(link-relocatable)
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endif
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# The profiling startfile is made by linking together the normal
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# startfile with gmon-start.o, which defines a constructor function
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# to turn on profiling code at startup.
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ifeq (yes,$(build-shared))
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$(objpfx)g$(start-installed-name): \
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$(objpfx)g%: $(objpfx)S% $(objpfx)gmon-start.os $(objpfx)static-reloc.os
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$(link-relocatable)
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$(objpfx)gr$(start-installed-name): \
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$(objpfx)gr%: $(objpfx)r% $(objpfx)gmon-start.o
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$(link-relocatable)
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ifneq ($(start-installed-name),$(static-start-installed-name))
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$(objpfx)g$(static-start-installed-name): \
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$(objpfx)g%: $(objpfx)% $(objpfx)gmon-start.o
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$(link-relocatable)
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$(objpfx)gr$(static-start-installed-name): \
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$(objpfx)gr%: $(objpfx)r% $(objpfx)gmon-start.o
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$(link-relocatable)
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endif
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else
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$(addprefix $(objpfx),$(sort g$(start-installed-name) \
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g$(static-start-installed-name))): \
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$(objpfx)g%: $(objpfx)% $(objpfx)gmon-start.o
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$(link-relocatable)
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endif
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# These extra files are sometimes expected by system standard linking
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# procedures, but we have nothing for them to do. So compile empty files.
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$(addprefix $(objpfx),$(filter-out $(start-installed-name), $(csu-dummies))):\
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$(before-compile)
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$(COMPILE.c) -o $@ -x c /dev/null
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# These headers are used by the startup code.
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$(objpfx)abi-tag.h: $(..)abi-tags
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$(make-target-directory)
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rm -f $@.new
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sed -e 's/#.*$$//' -e '/^[ ]*$$/d' $< | \
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while read conf tagos tagver; do \
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test `expr '$(config-machine)-$(config-vendor)-$(config-os)' \
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: "$$conf"` != 0 || continue; \
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( echo "$$tagos" | \
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sed -e 's/[^0-9xXa-fA-F ]//' \
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-e 's/^/#define __ABI_TAG_OS /'; \
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echo "#ifndef __ABI_TAG_VERSION"; \
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echo "$$tagver" | \
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sed -e 's/[^0-9xXa-fA-F]/ /g' -e 's/ *$$//' \
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-e 's/ /,/g' -e 's/^/# define __ABI_TAG_VERSION /'; \
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echo "#endif" ) > $@.new; \
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done
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if test -r $@.new; then mv -f $@.new $@; \
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else echo >&2 'This configuration not matched in $<'; exit 1; fi
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ifneq ($(multidir),.)
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$(addprefix $(objpfx)$(multidir)/, $(install-lib)): $(addprefix $(objpfx), $(install-lib))
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$(make-link-multidir)
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endif
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