Re: [PATCH 07/10] tools: Use -Og for debug builds when available

From: Jan Beulich <jbeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: xen-devel@lists.xenproject.org
Subject: Re: [PATCH 07/10] tools: Use -Og for debug builds when available
Date: Fri, 12 Feb 2021 17:14:11 +0100	[thread overview]
Message-ID: <da48c866-68cb-1655-2887-434d38e50b21@suse.com> (raw)
In-Reply-To: <3b02dfa7-923b-9bf7-a349-68bbba0590ad@citrix.com>

On 12.02.2021 17:09, Andrew Cooper wrote:
> On 12/02/2021 16:04, Jan Beulich wrote:
>> On 12.02.2021 16:39, Andrew Cooper wrote:
>>> --- a/tools/Rules.mk
>>> +++ b/tools/Rules.mk
>>> @@ -106,8 +106,9 @@ endif
>>>  CFLAGS_libxenlight += $(CFLAGS_libxenctrl)
>>>  
>>>  ifeq ($(debug),y)
>>> -# Disable optimizations
>>> -CFLAGS += -O0 -fno-omit-frame-pointer
>>> +# Use -Og if available, -O0 otherwise
>>> +dbg_opt_level := $(call cc-option,$(CC),-Og,-O0)
>>> +CFLAGS += $(dbg_opt_level) -fno-omit-frame-pointer
>> I wonder if we shouldn't do something similar for the hypervisor,
>> where we use -O1 for debug builds right now. At least when
>> DEBUG_INFO is also enabled, -Og may be better.
> 
> I also made that work... its rather more invasive in terms of changes -
> all for "maybe uninitialised" warnings.
> 
> $ git diff e2bab84984^ --stat
>  xen/Makefile                    | 3 ++-
>  xen/arch/arm/domain_build.c     | 2 +-
>  xen/arch/x86/irq.c              | 2 +-
>  xen/arch/x86/mm/shadow/common.c | 2 +-
>  xen/arch/x86/pv/shim.c          | 6 +++---
>  xen/arch/x86/sysctl.c           | 4 ++--
>  xen/common/efi/boot.c           | 2 +-
>  7 files changed, 11 insertions(+), 10 deletions(-)
> 
> is what is required to make Gitlab happy.

Oh, good to know. Thanks!

>  I was planning to defer it to 4.16 at this point.

Of course.

Jan