Re: [PATCH v6 3/7] Refactor arm_software_single_step to use regcache.

[Yao Qi <qiyaoltc@gmail.com>]

Antoine Tremblay <antoine.tremblay@ericsson.com> writes:

> +/* Calculate the offset from stack pointer of the pc register on the stack
> +   in the case of a sigreturn or sigreturn_rt syscall.  */
> +static int
> +arm_linux_sigreturn_next_pc_offset (unsigned long sp,
> +				    unsigned long sp_data,
> +				    unsigned long svc_number)
> +{
> +  /* Offset of R0 register.  */
> +  int r0_offset = 0;
> +  /* Offset of PC register.  */
> +  int pc_offset = 0;
> +
> +  gdb_assert (svc_number == 119 || svc_number == 173);
> +
> +  /* sigreturn.  */
> +  if (svc_number == 119)

Can we get rid of these magic numbers?

> +    {
> +      if (sp_data == ARM_NEW_SIGFRAME_MAGIC)
> +	r0_offset = ARM_UCONTEXT_SIGCONTEXT + ARM_SIGCONTEXT_R0;
> +      else
> +	r0_offset = ARM_SIGCONTEXT_R0;
> +    }
> +  /* rt_sigreturn. */
> +  else if (svc_number == 173)
> +    {
> +      if (sp_data == sp + ARM_OLD_RT_SIGFRAME_SIGINFO)
> +	r0_offset = ARM_OLD_RT_SIGFRAME_UCONTEXT + ARM_UCONTEXT_SIGCONTEXT
> +	  + ARM_SIGCONTEXT_R0;
> +      else
> +	r0_offset = ARM_NEW_RT_SIGFRAME_UCONTEXT + ARM_UCONTEXT_SIGCONTEXT
> +	  + ARM_SIGCONTEXT_R0;
> +    }
> +
> +  pc_offset = r0_offset + 4 * 15;
> +
> +  return pc_offset;
> +}
> +

> +
>  /* At a ptrace syscall-stop, return the syscall number.  This either
>     comes from the SWI instruction (OABI) or from r7 (EABI).
>  
> @@ -862,21 +924,21 @@ arm_linux_get_syscall_number (struct gdbarch *gdbarch,
>     instruction to be executed.  */
>  
>  static CORE_ADDR
> -arm_linux_syscall_next_pc (struct frame_info *frame)
> +arm_linux_syscall_next_pc (struct regcache *regcache)
>  {
> -  CORE_ADDR pc = get_frame_pc (frame);
> -  CORE_ADDR return_addr = 0;
> -  int is_thumb = arm_frame_is_thumb (frame);
> +  CORE_ADDR pc = regcache_read_pc (regcache);
> +  CORE_ADDR next_pc = 0;
> +  int is_thumb = arm_is_thumb (regcache);

Nit: looks you rename return_addr to next_pc.  If you don't that, the patch
can be shorter.  On the other hand, return_addr sounds a good variable
name to me, which means the address after syscall returns.

-- 
Yao (齐尧)