llvm dev - Jan 2020 - Custom Alloca implementation

Hello all,

In my project, I need to allocate an extra 4 Bytes in every Alloca
instruction. These additional bytes will be used to store the 'allocation
info'(like size and structure of the allocated object etc). Instead of
adding 4 bytes to the Alloca 'size' operand at every Alloca Instruction,
I
was thinking to make this change at the level where Alloca gets converted
to machine IR.
Can anyone please point me towards the code which actually handles this
conversion(lowering of Alloca Inst)?
-- 
Regards,
Udit kumar agarwal
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Hello Udit,
I'm not sure but can't you achieve the same just using metadata avoiding
to
change the alloca instruction?

Thanks
Alberto

On Mon, Jan 27, 2020, 12:09 Udit agarwal via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hello all,
>
> In my project, I need to allocate an extra 4 Bytes in every Alloca
> instruction. These additional bytes will be used to store the
'allocation
> info'(like size and structure of the allocated object etc). Instead of
> adding 4 bytes to the Alloca 'size' operand at every Alloca
Instruction, I
> was thinking to make this change at the level where Alloca gets converted
> to machine IR.
> Can anyone please point me towards the code which actually handles this
> conversion(lowering of Alloca Inst)?
> --
> Regards,
> Udit kumar agarwal
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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---Adding llvm-dev list to CC---
Hi Alberto,

Thanks for your prompt reply. Actually, I need this information(about total
allocation size and object structure) on runtime, so that is why I was
planning to encode this info and store it in the memory itself.

Regards,
Udit

On Mon, Jan 27, 2020 at 7:05 PM Alberto Barbaro <barbaro.alberto at
gmail.com>
wrote:
> Hello Udit,
> I'm not sure but can't you achieve the same just using metadata
avoiding
> to change the alloca instruction?
>
> Thanks
> Alberto
>
> On Mon, Jan 27, 2020, 12:09 Udit agarwal via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hello all,
>>
>> In my project, I need to allocate an extra 4 Bytes in every Alloca
>> instruction. These additional bytes will be used to store the
'allocation
>> info'(like size and structure of the allocated object etc). Instead
of
>> adding 4 bytes to the Alloca 'size' operand at every Alloca
Instruction, I
>> was thinking to make this change at the level where Alloca gets
converted
>> to machine IR.
>> Can anyone please point me towards the code which actually handles this
>> conversion(lowering of Alloca Inst)?
>> --
>> Regards,
>> Udit kumar agarwal
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
-- 
Regards,
Udit kumar agarwal
http://uditagarwal.in/
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