Hi all,
I ran into an issue since I moved from gcc 4.9.2 (Fedora 21) to gcc
5.1.1 (Fedora 22) when recompiling a piece of code.
The issue is with inline functions in a piece of code that ends up in a
shared library. The linker complains that it cannot find these functions
when declared inline. When declared static inline, everything seems fine.
I wrote some code to isolate the matter:
inline.c:
#include <stdio.h>
#ifndef MY_STATIC
#define MY_STATIC
#endif
MY_STATIC inline int the_inliner(int foo);
int do_main(int val)
{
int j;
j = the_inliner(val);
printf("Result: %d\n", j);
return j;
}
MY_STATIC inline int the_inliner(int foo)
{
return foo << 2;
}
(so the difference is whether this function is declared static inline or
just inline.)
user.c:
#include <stdio.h>
extern int do_main(int val);
int main(void)
{
int i = 100;
int j;
j = do_main(i);
printf("Result 2: %d\n", j);
return 0;
}
Makefile:
.PHONY: default clean
default: clean user.c inline.c
gcc --version
gcc -Wall -Winline -c -Wall -Werror -fpic inline.c -o inline.o
gcc -Wall -Winline -DMY_STATIC=static -c -Wall -Werror -fpic inline.c
-o inline_s.o
gcc -Wall -Winline -shared -o libinline.so inline.o
gcc -Wall -Winline -shared -o libinline_s.so inline_s.o
-gcc -Wall -Winline user.c -o user -L. -linline
gcc -Wall -Winline user.c -o user_s -L. -linline_s
-LD_LIBRARY_PATH=. ./user
LD_LIBRARY_PATH=. ./user_s
ls -l
clean:
rm -f *.o *.so user user_s
On gcc 4.8.2 on Fedora 21, this gives the expected result:
$ make
gcc --version
gcc (GCC) 4.9.2 20150212 (Red Hat 4.9.2-6)
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
gcc -Wall -Winline -c -Wall -Werror -fpic inline.c -o inline.o
gcc -Wall -Winline -DMY_STATIC=static -c -Wall -Werror -fpic inline.c -o
inline_s.o
gcc -Wall -Winline -shared -o libinline.so inline.o
gcc -Wall -Winline -shared -o libinline_s.so inline_s.o
gcc -Wall -Winline user.c -o user -L. -linline
gcc -Wall -Winline user.c -o user_s -L. -linline_s
LD_LIBRARY_PATH=. ./user
Result: 400
Result 2: 400
LD_LIBRARY_PATH=. ./user_s
Result: 400
Result 2: 400
ls -l
total 60
-rwxrwx---. 1 root vboxsf 276 Jun 26 23:35 inline.c
-rwxrwx---. 1 root vboxsf 1736 Jun 27 00:30 inline.o
-rwxrwx---. 1 root vboxsf 1688 Jun 27 00:30 inline_s.o
-rwxrwx---. 1 root vboxsf 8093 Jun 27 00:30 libinline.so
-rwxrwx---. 1 root vboxsf 8044 Jun 27 00:30 libinline_s.so
-rwxrwx---. 1 root vboxsf 662 Jun 27 00:08 Makefile
-rwxrwx---. 1 root vboxsf 8544 Jun 27 00:30 user
-rwxrwx---. 1 root vboxsf 156 Jun 26 23:34 user.c
-rwxrwx---. 1 root vboxsf 8544 Jun 27 00:30 user_s
On gcc 5.1.1 on Fedora 22, it fails when the inline function is not
declared static:
$ make
rm -f *.o *.so user user_s
gcc --version
gcc (GCC) 5.1.1 20150618 (Red Hat 5.1.1-4)
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
gcc -Wall -Winline -c -Wall -Werror -fpic inline.c -o inline.o
gcc -Wall -Winline -DMY_STATIC=static -c -Wall -Werror -fpic inline.c -o
inline_s.o
gcc -Wall -Winline -shared -o libinline.so inline.o
gcc -Wall -Winline -shared -o libinline_s.so inline_s.o
gcc -Wall -Winline user.c -o user -L. -linline
./libinline.so: undefined reference to `the_inliner'
collect2: error: ld returned 1 exit status
Makefile:13: recipe for target 'default' failed
make: [default] Error 1 (ignored)
gcc -Wall -Winline user.c -o user_s -L. -linline_s
LD_LIBRARY_PATH=. ./user
/bin/sh: ./user: No such file or directory
Makefile:13: recipe for target 'default' failed
make: [default] Error 127 (ignored)
LD_LIBRARY_PATH=. ./user_s
Result: 400
Result 2: 400
ls -l
total 48
-rw-rw-r--. 1 bmevisse bmevisse 276 Jun 26 23:35 inline.c
-rw-rw-r--. 1 bmevisse bmevisse 1640 Jun 27 00:32 inline.o
-rw-rw-r--. 1 bmevisse bmevisse 1688 Jun 27 00:32 inline_s.o
-rwxrwxr-x. 1 bmevisse bmevisse 8056 Jun 27 00:32 libinline.so
-rwxrwxr-x. 1 bmevisse bmevisse 8048 Jun 27 00:32 libinline_s.so
-rwxrwx---. 1 bmevisse bmevisse 662 Jun 27 00:08 Makefile
-rw-rw-r--. 1 bmevisse bmevisse 156 Jun 26 23:34 user.c
-rwxrwxr-x. 1 bmevisse bmevisse 8592 Jun 27 00:32 user_s
>From the documentation at
https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/Inline.html#Inline I cannot
make up why this doesn't work with gcc 5.1.1. This section of the manual
is 100% the same as for gcc 4.9.3.
Can someone please explain this to me?
Thanks,
Bas.
