[llvm-commits] [llvm] r79631 - in /llvm/trunk/lib/Target/PIC16:AsmPrinter/PIC16AsmPrinter.cpp AsmPrinter/PIC16AsmPrinter.hMCSectionPIC16.h PIC16.h PIC16PAN.h PIC16Passes/MakefilePIC16Passes/PIC16FrameOverlay.cppPIC16Passes/PIC16FrameOverlay.h PIC16Tar

[Chris Lattner]

On Aug 21, 2009, at 11:13 AM, Alireza.Moshtaghi at microchip.com wrote:

>>> Add a pass to do call graph analyis to overlay the autos and frame
>>> sections of
>>> leaf functions. This pass will be extended to color other nodes of
>>> the call tree
>>> as well in future.
>>
>> Sanjiv, this commit, r79562 and r79563 are not the right way to  
>> tackle
>> this problem, and are coming in the day of the release branch.   
>> Please
>> revert them and propose patches for these on llvmdev.
>
> Hi Chris
>
> The reason why we are doing these in backend is that cloning a  
> function
> is base on which functions call it and of course in frontend we don't
> have the view of the entire call graph. We'll be happy to revert  
> these,
> but I would like to know exactly why in your view.

We should discuss this on llvmdev, I think it came up before but there  
was no conclusive plan that was proposed.

In short, I think that this sort of thing should be modeled as an  
attribute on function definitions, not declarations.  I don't  
understand why you need to clone entire call graphs, but this is best  
discussed on llvmdev.

> With our current design wrto accessing auto variables, and how they  
> work
> in the cloned function, this is the best that we can do. Although,  
> it is
> likely that we change the design after 2.6 but we would prefer to  
> get as
> much of the functionality in 2.6 as possible because we want to base  
> an
> internal release of PIC16 compiler on llvm 2.6

Trying to cram things into 2.6 at the last minute is not  
acceptable. :)  For major things like this, it should have a real  
discussion about the design and the way forward and the implementation  
should have landed more than the day of the branch.

-Chris