[LLVMdev] Advice on MachineMoves and SEH

Rafael Ávila de Espíndola rafael.espindola at gmail.com
Thu Jun 2 06:20:30 PDT 2011


On 11-06-02 6:56 AM, Anton Korobeynikov wrote:
> Hi Chip,
>
>> Because of all this, it's hard to reconstruct the SEH information from
>> the MachineMove array. I have thought about adding a new array specific
>> to SEH information, but I'm not sure how you guys would feel about that.
>> Any ideas on how to solve this problem?
> Same problem with ARM-specific EH. I ended with own information
> scheme, where instructions are marked as "frame related" during all
> prologue&  epilogue emission and later are "recognized" during the MI
> =>  MCInst lowering. You might want to look into ARM backend, maybe we
> can somehow "generalize" this approach.
>

Yes, the current model of producing a on the side vector of machine 
moves doesn't look like the best thing to do now that we produce cfi 
directives.

I was thinking about just creating pseudo instructions that map 1:1 to 
the cfi directives (and ARM, and SEH). Codegen would create the 
appropriate one depending on the target. This would also avoid the silly 
labels that we still create when producing cfi.

Cheers,
Rafael



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