Re: [PATCH v3 2/2] gdb: Support stepping out from signal handler on riscv*-linux

[Pedro Alves <pedro@palves.net>]

On 2021-07-08 1:11 p.m., Lancelot SIX wrote:
> On Thu, Jul 08, 2021 at 11:49:02AM +0000, Lancelot SIX via Gdb-patches wrote:
>>>> @@ -3826,6 +3831,11 @@ riscv_next_pc (struct regcache *regcache, CORE_ADDR pc)
>>>>        if (src1 >= src2)
>>>>  	next_pc = pc + insn.imm_signed ();
>>>>      }
>>>> +  else if (insn.opcode () == riscv_insn::ECALL)
>>>> +    {
>>>> +      if (tdep->syscall_next_pc != nullptr)
>>>> +	next_pc = tdep->syscall_next_pc (get_current_frame ());
>>>
>>>
>>> 	else
>>> 	  next_pc += 4;
>>>
>>> ?
>>
>> OK, I’ll change that.
> 
> Actually, no.  I was a bit fast reading your comment and thought we
> where in the riscv_syscall_nexc_pc function.
> 
> The function is currently implemented as:
> 
> 	static CORE_ADDR
> 	riscv_next_pc (struct regcache *regcache, CORE_ADDR pc)
> 	{
> 	  struct riscv_insn insn;
> 	  CORE_ADDR next_pc
> 	  insn.decode (gdbarch, pc);
> 	  next_pc = pc + insn.length ();   // <--- The default case is already handled here
> 	
> 	  /* a bunch of ifs that can assign a new value to next_pc.  */
> 	  if (insn.opcode() == …)
> 	      next_pc = …
> 	  else if (insn.opcode() == …)
> 	      next_pc = …
> 	  […]
> 	
> 	  return next_pc;
> 	}
> 
> To make it clearer, the 'next_pc = pc + insn.length ();' statement could
> be the one to go in a final “catchall” else where you proposed to add
> the '+= 4' (note that when using the compressed instruction set,
> instructions can have a size of 2 bytes).

Ah, OK, sorry, I should have looked at the code instead of assuming.
Thanks for double checking.