[PATCH] doc: sandbox: Add a note of disabling LTO when using gdb

[PATCH] doc: sandbox: Add a note of disabling LTO when using gdb

[Bin Meng]

Image created by LTO is not friendly to debugger, let's document this.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
---

 doc/arch/sandbox.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst
index 246ab5b380..19167d22fb 100644
--- a/doc/arch/sandbox.rst
+++ b/doc/arch/sandbox.rst
@@ -477,6 +477,8 @@ board_init_f() and board_init_r().
 
 This approach can be used on normal boards as well as sandbox.
 
+When debugging with gdb, it's better to disable Link Timer Optimizations
+(CONFIG_LTO = n).
 
 SDL_CONFIG
 ----------
-- 
2.25.1

Re: [PATCH] doc: sandbox: Add a note of disabling LTO when using gdb

[Heinrich Schuchardt]

On 5/17/22 18:21, Bin Meng wrote:
> Image created by LTO is not friendly to debugger, let's document this.
>
> Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
> ---
>
>   doc/arch/sandbox.rst | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst
> index 246ab5b380..19167d22fb 100644
> --- a/doc/arch/sandbox.rst
> +++ b/doc/arch/sandbox.rst
> @@ -477,6 +477,8 @@ board_init_f() and board_init_r().
>
>   This approach can be used on normal boards as well as sandbox.
>
> +When debugging with gdb, it's better to disable Link Timer Optimizations
> +(CONFIG_LTO = n).

CC_OPTIMIZE_FOR_DEBUG should be mentioned here too.

I will add this when merging.

Should CC_OPTIMIZE_FOR_DEBUG disable LTO?

The usefulness of LTO=n, CC_OPTIMIZE_FOR_DEBUG=y for debugging is not
sandbox specific but applies to QEMU and JTAG debugging too.

I think the section "Debugging the init sequence" should not live on a
page that is sandbox specific. Instead we should add a new page on
debugging U-Boot.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

>
>   SDL_CONFIG
>   ----------