Why do we use -g option of gcc even for RELEASE build?

Why do we use -g option of gcc even for RELEASE build?

[Heyi Guo]

Hi folks,

 From gcc manual, -g option seems to produce debugging information. In 
tools_def.template, -g is included in GCC_ALL_CC_FLAGS, so it will also 
be enabled for RELEASE build with gcc tool chain. Any special reason to 
do that?

Thanks and regards,

Heyi

Re: Why do we use -g option of gcc even for RELEASE build?

[Laszlo Ersek]

On 11/08/17 03:25, Heyi Guo wrote:
> Hi folks,
> 
> From gcc manual, -g option seems to produce debugging information. In
> tools_def.template, -g is included in GCC_ALL_CC_FLAGS, so it will also
> be enabled for RELEASE build with gcc tool chain. Any special reason to
> do that?

In the edk2 tree, -g was added to GCC_ALL_CC_FLAGS and
GCC44_ALL_CC_FLAGS in commit 52302d4dee58 ("Sync EDKII BaseTools to
BaseTools project r1903.", 2010-02-28).

If you check the history of the now-historical separate BaseTools
project <https://github.com/tianocore/buildtools-BaseTools.git>, "-g"
was introduced in commit 46c1e64305d4 ("Upgrade the binutil 2.18.50.0.5
to 2.20.51.0.5 for UNIXGCC tool chain", 2010-02-25).

I guess that the same <Command.GCC> for [Dynamic-Library-File] must be
able to work for both DEBUG/NOOPT and RELEASE builds. So -g is included
for all of those build targets, in the C flags. Ultimately the debug
symbols are not copied into the .efi binaries, for RELEASE, I believe.

Thanks
Laszlo

Re: Why do we use -g option of gcc even for RELEASE build?

[Gao, Liming]

In build_rule.txt, GCC built image will be strip first, then be converted to EFI image by GenFw. There is no symbol in the final EFI image. All symbols are kept into original GCC built image. 

Thanks
Liming
> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, November 8, 2017 10:54 PM
> To: Heyi Guo <heyi.guo@linaro.org>; edk2-devel@lists.01.org
> Cc: Gao, Liming <liming.gao@intel.com>
> Subject: Re: [edk2] Why do we use -g option of gcc even for RELEASE build?
> 
> On 11/08/17 03:25, Heyi Guo wrote:
> > Hi folks,
> >
> > From gcc manual, -g option seems to produce debugging information. In
> > tools_def.template, -g is included in GCC_ALL_CC_FLAGS, so it will also
> > be enabled for RELEASE build with gcc tool chain. Any special reason to
> > do that?
> 
> In the edk2 tree, -g was added to GCC_ALL_CC_FLAGS and
> GCC44_ALL_CC_FLAGS in commit 52302d4dee58 ("Sync EDKII BaseTools to
> BaseTools project r1903.", 2010-02-28).
> 
> If you check the history of the now-historical separate BaseTools
> project <https://github.com/tianocore/buildtools-BaseTools.git>, "-g"
> was introduced in commit 46c1e64305d4 ("Upgrade the binutil 2.18.50.0.5
> to 2.20.51.0.5 for UNIXGCC tool chain", 2010-02-25).
> 
> I guess that the same <Command.GCC> for [Dynamic-Library-File] must be
> able to work for both DEBUG/NOOPT and RELEASE builds. So -g is included
> for all of those build targets, in the C flags. Ultimately the debug
> symbols are not copied into the .efi binaries, for RELEASE, I believe.
> 
> Thanks
> Laszlo

Re: Why do we use -g option of gcc even for RELEASE build?

[Heyi Guo]

That makes sense. Thank you all :)

Regards,

Heyi


在 11/8/2017 11:32 PM, Gao, Liming 写道:
> In build_rule.txt, GCC built image will be strip first, then be converted to EFI image by GenFw. There is no symbol in the final EFI image. All symbols are kept into original GCC built image.
>
> Thanks
> Liming
>> -----Original Message-----
>> From: Laszlo Ersek [mailto:lersek@redhat.com]
>> Sent: Wednesday, November 8, 2017 10:54 PM
>> To: Heyi Guo <heyi.guo@linaro.org>; edk2-devel@lists.01.org
>> Cc: Gao, Liming <liming.gao@intel.com>
>> Subject: Re: [edk2] Why do we use -g option of gcc even for RELEASE build?
>>
>> On 11/08/17 03:25, Heyi Guo wrote:
>>> Hi folks,
>>>
>>>  From gcc manual, -g option seems to produce debugging information. In
>>> tools_def.template, -g is included in GCC_ALL_CC_FLAGS, so it will also
>>> be enabled for RELEASE build with gcc tool chain. Any special reason to
>>> do that?
>> In the edk2 tree, -g was added to GCC_ALL_CC_FLAGS and
>> GCC44_ALL_CC_FLAGS in commit 52302d4dee58 ("Sync EDKII BaseTools to
>> BaseTools project r1903.", 2010-02-28).
>>
>> If you check the history of the now-historical separate BaseTools
>> project <https://github.com/tianocore/buildtools-BaseTools.git>, "-g"
>> was introduced in commit 46c1e64305d4 ("Upgrade the binutil 2.18.50.0.5
>> to 2.20.51.0.5 for UNIXGCC tool chain", 2010-02-25).
>>
>> I guess that the same <Command.GCC> for [Dynamic-Library-File] must be
>> able to work for both DEBUG/NOOPT and RELEASE builds. So -g is included
>> for all of those build targets, in the C flags. Ultimately the debug
>> symbols are not copied into the .efi binaries, for RELEASE, I believe.
>>
>> Thanks
>> Laszlo

Re: Why do we use -g option of gcc even for RELEASE build?

[Paolo Bonzini]

On 08/11/2017 03:25, Heyi Guo wrote:
> From gcc manual, -g option seems to produce debugging information. In
> tools_def.template, -g is included in GCC_ALL_CC_FLAGS, so it will also
> be enabled for RELEASE build with gcc tool chain. Any special reason to
> do that?

Why *not* actually?  Debug information only costs disk space, it is not
part of the firmware image (and even for native Linux binaries it is not
loaded in memory).

Paolo