[sheepdog] [PATCH] Fix hardcode AMD64 assembly code (RSP)

[Hitoshi Mitake]

At Mon, 29 Jul 2013 14:41:35 +0800,
Liu Yuan wrote:
> 
> On Sun, Jul 28, 2013 at 02:05:49AM +0800, YunQiang Su wrote:
> > RSP is a register name only for AMD64 (x86_64) platform,
> > while on other platform it may be another name.
> > 
> > On i386 (x86_32) platform, it is "esp".
> > On most of RISC platform (PowerPC, SPARC, MIPS, ARM, etc),
> > it is "sp".
> > ---
> >  include/logger.h | 23 ++++++++++++++++++++++-
> >  lib/logger.c     |  5 -----
> >  2 files changed, 22 insertions(+), 6 deletions(-)
> > 
> > diff --git a/include/logger.h b/include/logger.h
> > index 79eb108..81691b2 100644
> > --- a/include/logger.h
> > +++ b/include/logger.h
> > @@ -38,10 +38,31 @@ void log_write(int prio, const char *func, int line, const char *fmt, ...)
> >  void set_thread_name(const char *name, bool show_idx);
> >  void get_thread_name(char *name);
> >  
> > +#ifdef __i386__
> > +#define SP_REG "esp"
> > +#elif defined(__x86_64__)
> > +#define SP_REG "rsp"
> > +#elif defined(__mips__) || defined(__sparc__) || \
> > +      defined (__arm__) || (defined __powerpc__) || \
> > +      defined (__s390__) || (defined __s390x__) || \
> > +      defined (__ia64__)
> > +#define SP_REG "sp"
> > +#endif
> > +
> > +#ifdef SP_REG
> > +#define dump_stack_frames() ({			\
> > +	register void *current_sp asm(SP_REG);	\
> > +	__dump_stack_frames(current_sp);	\
> > +})
> >  #define sd_dump_variable(var) ({		\
> > -	register void *current_sp asm("rsp");	\
> > +	register void *current_sp asm(SP_REG);	\
> >  	__sd_dump_variable(#var, current_sp);	\
> >  })
> > +#else
> > +#define dump_stack_frames() ()
> > +#define sd_dump_variable(var) ()
> > +#endif
> > +
> >  int __sd_dump_variable(const char *var, const void *base_sp);
> >  void sd_backtrace(void);
> >  
> > diff --git a/lib/logger.c b/lib/logger.c
> > index 253163d..ba55adc 100644
> > --- a/lib/logger.c
> > +++ b/lib/logger.c
> > @@ -742,11 +742,6 @@ notrace int __sd_dump_variable(const char *var, const void *base_sp)
> >  	return 0;
> >  }
> >  
> > -#define dump_stack_frames() ({			\
> > -	register void *current_sp asm("rsp");	\
> > -	__dump_stack_frames(current_sp);	\
> > -})
> > -
> >  __attribute__ ((__noinline__))
> >  static notrace int __dump_stack_frames(const void *base_sp)
> >  {
> > -- 
> 
> I've come up with a better fix. Which use the gcc builtin function to get the
> stack pointer.
> 
> From 44300c3fe580a677757803cc30838923ccc5b748 Mon Sep 17 00:00:00 2001
> From: Liu Yuan <namei.unix at gmail.com>
> Date: Mon, 29 Jul 2013 14:33:58 +0800
> Subject: [PATCH] sheep: use gcc builtin to get stack frame pointer
> 
> This remove hardcoded assembly which is not portable.
> 
> Signed-off-by: Liu Yuan <namei.unix at gmail.com>
> 
> diff --git a/include/logger.h b/include/logger.h
> index 79eb108..9253548 100644
> --- a/include/logger.h
> +++ b/include/logger.h
> @@ -39,10 +39,9 @@ void set_thread_name(const char *name, bool show_idx);
>  void get_thread_name(char *name);
>  
>  #define sd_dump_variable(var) ({		\
> -	register void *current_sp asm("rsp");	\
> -	__sd_dump_variable(#var, current_sp);	\
> +	__sd_dump_variable(#var);		\
>  })
> -int __sd_dump_variable(const char *var, const void *base_sp);
> +int __sd_dump_variable(const char *var);
>  void sd_backtrace(void);
>  
>  /* sheep log priorities, comliant with syslog spec */
> diff --git a/lib/logger.c b/lib/logger.c
> index 253163d..da1221b 100644
> --- a/lib/logger.c
> +++ b/lib/logger.c
> @@ -697,11 +697,15 @@ static bool check_gdb(void)
>  	return system("which gdb > /dev/null") == 0;
>  }
>  
> +#define STACK_POINTER	\
> +	((char *)__builtin_frame_address(0) + __SIZEOF_POINTER__ * 2)

Doesn't this depend on the ABI of x86?
# I don't know ABIs of other architectures supported in YunQiang's
# patch. Do you know their ABIs?

Thanks,
Hitoshi