Re: [PATCH] Fixes for i686-pc-linux-newlib

[Jeff Johnston <jjohnstn at redhat dot com>]

Paolo,

  A number of issues with this patch.  First of all, I usually build 
x86-linux apps with -nostdlib and manually specify newlib's crt0.o. 
This basic test fails with the patch below because _init and _fini 
aren't defined in newlib (we don't supply crt[1/n/o] .o files at 
present).  Hacking past that initial problem, I ran into a problem 
building a hello world program with -fprofile-arcs and -ftest-coverage. 
 These options drag in libgcov.a which was built with glibc headers and 
it expects some magic symbols that aren't in newlib (e.g. stderr, 
__errno_location, and __fxstat).  I hacked past the link problem by 
adding newlib symbols and linking in /usr/lib/crti.o but I eventually 
ended up with a SIGSEGV.

  Could you elaborate on how you built your application to get profile 
data output?  Can you verify that you actually have a newlib application 
as opposed to one that is using glibc?

-- Jeff J.

Paolo Bonzini wrote:
> The first hunk is a work around for the (in)famous INSTALL = ../ bug.  
> We can just pass down INSTALL as we detect it correctly in the toplevel 
> configure and in newlib's configure.
>
> The second hunk is needed to invoke initialization and finalization 
> functions.  I tested it by running a program compiled with gcc and with 
> profiling enabled.  It creates the .gcda file correctly.
>
> Can you apply them?  I have no copyright on file, but these are small 
> enough to not require it.
>
> 2005-06-03  Paolo Bonzini  <bonzini@gnu.org>
>
>       * Makefile.am (AM_MAKEFLAGS): Pass down INSTALL.
>       * libc/sys/linux/machine/i386/crt0.c (_start): Invoke _init and 
> _fini.
>
> Paolo
>
>
> ------------------------------------------------------------------------
>
> Index: Makefile.am
> ===================================================================
> RCS file: /cvs/src/src/newlib/Makefile.am,v
> retrieving revision 1.35
> diff -u -p -r1.35 Makefile.am
> --- Makefile.am	8 Sep 2005 22:45:49 -0000	1.35
> +++ Makefile.am	3 Jan 2006 19:01:02 -0000
> @@ -50,6 +50,7 @@ AM_MAKEFLAGS = \
>  	"LD=$(LD)" \
>  	"LIBCFLAGS=$(LIBCFLAGS)" \
>  	"NM=$(NM)" \
> +	"INSTALL=$(INSTALL)" \
>  	"PICFLAG=$(PICFLAG)" \
>  	"RANLIB=$(RANLIB)" \
>  	"DESTDIR=$(DESTDIR)"
> Index: libc/sys/linux/machine/i386/crt0.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/sys/linux/machine/i386/crt0.c,v
> retrieving revision 1.5
> diff -u -p -r1.5 crt0.c
> --- libc/sys/linux/machine/i386/crt0.c	10 Sep 2002 00:46:45 -0000	1.5
> +++ libc/sys/linux/machine/i386/crt0.c	3 Jan 2006 19:01:04 -0000
> @@ -16,6 +16,9 @@ extern char **environ;
>  
>  extern int main(int argc,char **argv,char **envp);
>  
> +extern void _init (void);
> +extern void _fini (void);
> +
>  extern char _end;
>  extern char __bss_start;
>  
> @@ -41,5 +44,8 @@ void _start(int args)
>       *       by this time by Linux.  */
>  
>      tzset(); /* initialize timezone info */
> +
> +    atexit (_fini);
> +    _init ();
>      exit(main(argc,argv,environ));
>  }