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From: Simon Marchi <simon.marchi@polymtl.ca>
To: "Ge, Lei" <Lei.Ge@windriver.com>,
	"gdb@sourceware.org" <gdb@sourceware.org>
Cc: "Xin, Wenyan" <Wenyan.Xin@windriver.com>
Subject: Re: GDB will set bp at a function for RISC-V when step over this function call
Date: Sat, 18 Sep 2021 22:04:23 -0400	[thread overview]
Message-ID: <a86e6201-7da7-6ec7-f720-49b3883987fb@polymtl.ca> (raw)
In-Reply-To: <BYAPR11MB26632A15985C8FC698BC961697DD9@BYAPR11MB2663.namprd11.prod.outlook.com>

On 2021-09-17 3:57 a.m., Ge, Lei wrote:
> Hi all,
> 
> I have a question about GDB for RISC-V. When step over a function call, GDB will set a bp at this function only for RISC-V. Do you think it is a bug? Thanks.

Hi,

Probably because RISC-V uses software single step to implement
single instruction stepping.  It implements the
gdbarch_software_single_step hook:

https://gitlab.com/gnutools/binutils-gdb/-/blob/master/gdb/riscv-tdep.c#L3923-3940

Note that this callback is only installed in riscv_fbsd_init_abi and
riscv_linux_init_abi, so is only effective when debugging a Linux or
FreeBSD target.  So I suppose that if you were debugging a bare-metal
application, GDB would use hardware single step instead, not sure if
that is by design.

Simon

  reply	other threads:[~2021-09-19  2:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-17  7:57 Ge, Lei
2021-09-19  2:04 ` Simon Marchi [this message]
2021-09-20 17:06   ` John Baldwin
2021-09-22 21:48     ` Jim Wilson

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