[LLVMdev] MachO and ELF Writers/MachineCodeEmitters arehard-codedinto LLVMTargetMachine

[Aaron Gray]

On Sun, Mar 15, 2009 at 10:52 PM, Aaron Gray <
aaronngray.lists at googlemail.com> wrote:

>  I like the idea of a generic MachineCodeWriter, although I prefer the
>> name 'ObjectFileWriter'...
>>
>
> Thats much more descriptive of the functionality.
>

Sorry, I disagree actually the MachineCodeEmitter or the
'MachineCodeWritter' does not do any file handling at all. Do look at the
code for the MachineCodeWritter and you will see it only writes to memory
and if it reaches the end of the allotted memory I believe higher ordered
logic reallocates a larget buffer and starts again from scratch. This could
be avoided if they generated fixus for absolute memory references refering
within the outputted code. Then a alloc function could be called before
outputting say a 4 byte int and could realloc and copy code and when finally
written the fixups could be applied.

I am also wondering about the efficiency of std::vector whether we could use
that for the MachineCodeWriter, or whether we write out own code output
stream/buffering ?

I still think this is where the crux of the problem lies the upper logic is
relatively simple compared to this buy looking at what you say it is
important to get it right.

Cheers,

Aaron
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