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Re: [PATCH/AArch64 2/4] Remove the artificial limit on code alignment through the use of the fixed part of a fragment for output generation only, which required MAX_MEM_FOR_RS_ALIGN_CODE to be large enough to hold the maximum pad.
- From: Andrew Pinski <pinskia at gmail dot com>
- To: Marcus Shawcroft <marcus dot shawcroft at gmail dot com>
- Cc: Philipp Tomsich <philipp dot tomsich at theobroma-systems dot com>, "binutils at sourceware dot org" <binutils at sourceware dot org>
- Date: Tue, 28 Oct 2014 01:55:26 -0700
- Subject: Re: [PATCH/AArch64 2/4] Remove the artificial limit on code alignment through the use of the fixed part of a fragment for output generation only, which required MAX_MEM_FOR_RS_ALIGN_CODE to be large enough to hold the maximum pad.
- Authentication-results: sourceware.org; auth=none
- References: <CA+=Sn1nxGT+x9JgJo=B6iOBKcOz0xWiF5nf2t=6vgVz+eMSpDQ at mail dot gmail dot com> <1388666881-20727-1-git-send-email-philipp dot tomsich at theobroma-systems dot com> <CAFqB+PyuGmvsZ=MUVzm9Vj5YJXuVXfwqZYK7CT6KoLgumt6zoA at mail dot gmail dot com>
On Tue, Jan 7, 2014 at 4:49 AM, Marcus Shawcroft
> A few minor issues....
Any news on this patch since it never went in? Could you also remove
Right now even a simple:
> On 2 January 2014 12:48, Philipp Tomsich
> <firstname.lastname@example.org> wrote:
>> + Here we fill the frag with the appropriate info for padding the output
>> + stream. The resulting frag will consist of a fixed (fr_fix) and of a
> GNU style places two spaces after a period. Same comment applies
> through the patch.
>> + repeating (fr_var) part.
>> + The fixed content is always emitted before the repeating content and
>> + these two parts are used as follows in constructing the output:
>> + - the fixed part will be used to align to a valid instruction word
>> + boundary, in case that we start at a misaligned address; as no
>> + executable instruction can live at the misaligned location, we
>> + simply fill with zeros;
>> + - the variable part will be used to cover the remaining padding and
>> + we fill using the AArch64 NOP instruction.
>> + Note that the size of a RS_ALIGN_CODE fragment is always 7 to provide
>> + enough storage space for up to 3 bytes for padding the back to a valid
>> + instruction alignment and exactly 4 bytes to store the NOP pattern.
>> + */
> Remove the trailing white space throughout the patch please.
>> -aarch64_handle_align (fragS * fragP)
>> +aarch64_handle_align (fragS * frag)
> Please don't mix rename / reformat with functional changes, it makes
> it harder to review the patch. In this case fragP -> frag is an
> unrelated change, either split the patch into two one with a rename
> the other with the functional change, or drop the rename completely.
>> /* NOP = d503201f */
>> /* AArch64 instructions are always little-endian. */
> Double space after period.
>> @@ -5765,69 +5783,32 @@ aarch64_handle_align (fragS * fragP)
>> int bytes, fix, noop_size;
>> char *p;
>> - const char *noop;
>> - if (fragP->fr_type != rs_align_code)
>> + if (frag->fr_type != rs_align_code)
>> - bytes = fragP->fr_next->fr_address - fragP->fr_address - fragP->fr_fix;
>> - p = fragP->fr_literal + fragP->fr_fix;
>> - fix = 0;
>> - if (bytes > MAX_MEM_FOR_RS_ALIGN_CODE)
>> - bytes &= MAX_MEM_FOR_RS_ALIGN_CODE;
>> + bytes = frag->fr_next->fr_address - frag->fr_address - frag->fr_fix;
>> + p = frag->fr_literal + frag->fr_fix;
>> #ifdef OBJ_ELF
>> - gas_assert (fragP->tc_frag_data.recorded);
>> + gas_assert (frag->tc_frag_data.recorded);
>> - noop = aarch64_noop;
>> - noop_size = sizeof (aarch64_noop);
>> - fragP->fr_var = noop_size;
>> + noop_size = sizeof(aarch64_noop);
> Inappropriate removal of the white space before the opening parenthesis.