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Re: RFC: Alignment and sizes of .note.ABI-tag and .note.gnu.build-id in 64-bit ELF objects

From: Nicholas Miell <nmiell at gmail dot com>
To: "H.J. Lu" <hjl dot tools at gmail dot com>, Binutils <binutils at sourceware dot org>, GNU C Library <libc-alpha at sourceware dot org>
Date: Fri, 31 Mar 2017 13:30:31 -0700
Subject: Re: RFC: Alignment and sizes of .note.ABI-tag and .note.gnu.build-id in 64-bit ELF objects
Authentication-results: sourceware.org; auth=none
Newsgroups: gmane.comp.gnu.binutils, gmane.comp.lib.glibc.alpha
References: <CAMe9rOrnxJeW7ef8yZ3QZ5RA5ktjFmu9c1QW79w=pfs6wiOemw@mail.gmail.com>

On 03/31/2017 10:17 AM, H.J. Lu wrote:

According to gABI, in 64-bit objects, each note entry is an array of 8-bye
words in the format of the target processor.  But I got

  [ 2] .note.ABI-tag     NOTE            0000000000000254 000254
000020 00   A  0   0  4
  [ 3] .note.gnu.build-id NOTE            0000000000000274 000274
000024 00   A  0   0  4

on x86-64.  .note.ABI-tag size is 32, but it isn't aligned at 8 bytes.
.note.gnu.build-id size is 36, which isn't multiple of 8 bytes.  Should
they be padded to multiple of 8 bytes and aligned to 8 bytes for 64-bit
objects?

The spec is wrong, ELF notes are always arrays of 4-byte words in theformat of the target processor.

References:
- RFC: Alignment and sizes of .note.ABI-tag and .note.gnu.build-id in 64-bit ELF objects
  - From: H.J. Lu

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