[LLVMdev] LLD: representation of a power of two value

[Rui Ueyama]

I'll update wherever we use log2 instead of a value itself.

On Wed, Mar 25, 2015 at 11:37 AM, Shankar Easwaran <shankare at codeaurora.org>
wrote:

> Its only atoms. I was hinting at default output section alignments in the
> ELF writer.
>
>
> On 3/25/2015 12:44 PM, Rui Ueyama wrote:
>
>> I guess I'm talking about atoms. Do we have notion of section in LLD?
>>
>> On Wed, Mar 25, 2015 at 8:35 AM, Shankar Easwaran <
>> shankare at codeaurora.org>
>> wrote:
>>
>>  On 3/24/2015 7:51 PM, Rui Ueyama wrote:
>>>
>>>  On Tue, Mar 24, 2015 at 5:40 PM, Nick Kledzik <kledzik at apple.com>
>>>> wrote:
>>>>
>>>>   On Mar 24, 2015, at 5:09 PM, Rui Ueyama <ruiu at google.com> wrote:
>>>>
>>>>>   It's not a big deal, but it always annoyed me a bit when I hit it, so
>>>>> I'll bring it up here.
>>>>>
>>>>>  LLD represents an alignment X as log2(X) in some places and just X in
>>>>>>
>>>>>>  other places. It's a bit confusing. Because I always think
>>>>> alignments in
>>>>> my
>>>>> mind in terms of 1, 2, 4, 8, ..., instead of 2^1, 2^2, 2^3, ..., I'd
>>>>> like
>>>>> to propose to always use real values.
>>>>> Can you give some examples?
>>>>>
>>>>> The DefinedAtom class has struct:
>>>>>
>>>>>       struct Alignment {
>>>>>           uint16_t powerOf2;
>>>>>           uint16_t modulus;
>>>>>       };
>>>>>
>>>>> That use seems clear.   But, yes, if there is “int alignment”
>>>>> somewhere,
>>>>> that is ambiguous.
>>>>>
>>>>>   At least in ELF, alignment values are represented not by exponents
>>>>> but
>>>>>
>>>> by
>>>> just numbers in files, so we convert them back and force. "Alignment" is
>>>> used for both exponents and actual values there.
>>>>
>>>>  I believe you are mentioning about section alignments, that are being
>>> differentiated from atom alignments ?
>>>
>>> If so are you planning to change the variable name (or) use Alignment
>>> even
>>> there ?
>>>
>>> Shankar Easwaran
>>>
>>> --
>>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted
>>> by the Linux Foundation
>>>
>>>
>>>
>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted
> by the Linux Foundation
>
>
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