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Re: [Minios-devel] Should we have to be aware of GCC version in Unikraft?



Hey Wei,

we have some code in the build system that stores the used GCC version in a variable already. Have a look to Makefile in the base directory and search for CC_VERSION. Maybe you need to modify it - e.g., separate major and minor number. There is no code or Makefile that uses this variable currently. So, you do not need to worry that something would break.

On 12.03.2018 08:26, Wei Chen wrote:
Hi Simon,

In Unikraft, we will add corresponding GCC flags to do processor optimization
for target processor. In this case, I want to list a full set of standard ARMv8
Cortex-A series processors (from Cortex-a53 to latest Cortex-a75) in this menu.

But different GCC version supports different processors set for -mtune. For
example the latest gcc-7 can support the full set of standard ARMv8 Cortex-A
series processors, but gcc-4.9 only supports cortex-a53 and cortex-a57. Other
processor values for -mtune will get an error about "invalid parameter" for
gcc-4.9.


What I would raise an error with Make via the architecture's Makefile.uk if the used GCC version is too old for a specific CPU mtune switch. The error should tell the user that a newer GCC version is required.

In this case, should we import the GCC version into Unikraft's build system?
If yes, we can provide different processor list for different GCC version.
Another method is to use a minimal set of processors (cortex-a53, cortex-a57)
to avoid such error. But we will not be able to optimize code for latest ARM
processors.

I am not sure whether x86 has similar issue?


Did not happen yet but might in the future, too.

Regards,
Wei Chen


Thanks,

Simon

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