[PATCH] D29827: [AVR] Add -mmcu option to the driver

[Peter Wu via Phabricator via cfe-commits]

Lekensteyn added inline comments.


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Comment at: include/clang/Driver/Options.td:1613
 def mcpu_EQ : Joined<["-"], "mcpu=">, Group<m_Group>;
+def mmcu_EQ : Joined<["-"], "mmcu=">, Group<m_Group>;
 def mdynamic_no_pic : Joined<["-"], "mdynamic-no-pic">, Group<m_Group>;
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dylanmckay wrote:
> Lekensteyn wrote:
> > jroelofs wrote:
> > > Would it make sense to have mcu be an alias for mcpu instead?
> > That would deviate from the GCC interface, so I have chosen for the current situation:
> > ```
> > $ avr-gcc -mmcu=avr2 -o /dev/null x.c
> > $ avr-gcc -mcpu=avr2 -o /dev/null x.c
> > avr-gcc: error: unrecognized command line option '-mcpu=avr2'
> > $ avr-gcc -march=avr2 -o /dev/null x.c
> > avr-gcc: error: unrecognized command line option '-march=avr2'
> > $ avr-gcc -v
> > ...
> > gcc version 6.3.0 (GCC)
> > ```
> I think @jroelofs  means that it is possible to make `mmcu` an alias of `mmcu` internally. This would mean we wouldn't need to add AVR-specific `getCPUName` handling.
If mmcu is made an alias of mcpu, wouldn't that mean that both `-mcpu` and `-mmcu` would be accepted by driver (undesirable)?
As far as I can see, `-target-cpu` must be passed to the frontend and assembler, `-mcpu=` is not recognized as option. And ensuring that `getCPUName` returns a non-empty string ensures that `-target-cpu` is passed.

I am quite new to the internals, so please let me know if I misunderstood something :-)


https://reviews.llvm.org/D29827