[trans-mem] Add documentation

[Richard Henderson]

On 05/31/2011 11:55 AM, Torvald Riegel wrote:
> Last majority opinion on this that I'm aware of said that only primitive
> types can be used for exceptions thrown out of transactions. We should
> be able to handle this with the EH ABI wrappers only.
> 
> Okay to drop support of dropReferences()?

Fine by me.

>> The intention was always to drop the registration functions entirely, and
>> create a new ELF Phdr describing the linker-sorted table.  Much like what
>> currently happens for PT_GNU_EH_FRAME.
>>
>> This work kept getting bogged down in how to represent the N different code
>> generation variants.  We clearly needed at least 2 -- sw and hw transactional
>> clones -- but there was always a suggestion of more variants for different
>> tm assumptions/invariants.
> 
> Shall I just add your text to the document as an explanation?

Sure.

>> I thought the TM Language group, and Hans Bohem in particular, has been
>> working on this.  It post-dates the language spec we had available when
>> the branch code was written.
> 
> The only memory-model-related work that I'm aware of is what's contained
> in the C++-level specification (embedding txns into the C++1x mem
> model), but not on the ABI level. I'll try to get more information about
> this.

Ah, I equated these to the same thing.


r~