Zitat von K Lakshman <[email protected]>:
I'm trying to build a shared library (gcc on Linux CentOS) with -pie
flag. If I
simply add the flag -pie to CMAKE_SHARED_LINKER_FLAGS "-Wl,-pie", the command
that gets invoked looks like this:
gcc -shared -Wl,-pie <rest of the command> -o libmylibrary.so
A shared library built like this is not runnable stand-alone (I get an error
/usr/lib/libc.so: bad ELF interpreter: No such file or directory).
Where as if I
can get the shared library to be built using this command:
gcc -Wl,-shared -Wl,-pie <rest of the command> -o libmylibrary.so
then that shared library seems to run fine stand alone. (The only difference
betweent the two commands is that the -shared flags is passed to gcc in the
first version and directly to the linker in the second version thus bypassing
collect2).
How do I change the shared library build command to use -Wl,-shared
instead of
-shared? Do I have to write a complete custom command or can I use
some tricks
to simply change this part alone?
Does that actually make sense? To cite from gcc manpage:
-pie
Produce a position independent executable on targets which
support it. For predictable results, you must also specify the same
set of options that were used to generate code (-fpie, -fPIE, or model
suboptions) when you specify this option.
-shared
Produce a shared object which can then be linked with other
objects to form an executable. Not all systems support this option.
For predictable results, you must also specify the same set of options
that were used to generate code (-fpic, -fPIC, or model suboptions)
when you specify this option.[1]
So, you should NOT use -pie for shared libraries (which are _already_
position independent) but only for static libraries and executables,
if you really want that.
Additionally, you then use "gcc -pie", not "gcc -Wl,-pie".
HS
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