From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 5B2DC388C007; Fri, 22 Jan 2021 01:38:17 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5B2DC388C007
From: "i at maskray dot me" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/95095] Feature request: support -fno-unique-section-names
Date: Fri, 22 Jan 2021 01:38:17 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: unknown
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: i at maskray dot me
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-95095-4-Ob3C5cwBDy@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-95095-4@http.gcc.gnu.org/bugzilla/>
References: <bug-95095-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Fri, 22 Jan 2021 01:38:17 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95095

--- Comment #5 from Fangrui Song <i at maskray dot me> ---
Linux kernel

include/asm-generic/vmlinux.lds.h currently has
#define TEXT_TEXT                                                       \
                ALIGN_FUNCTION();                                       \
                *(.text.hot .text.hot.*)                                \
                *(TEXT_MAIN .text.fixup)                                \
                *(.text.unlikely .text.unlikely.*)                      \
                *(.text.unknown .text.unknown.*)                        \
                NOINSTR_TEXT                                            \
                *(.text..refcount)                                      \
                *(.ref.text)                                            \
        MEM_KEEP(init.text*)                                            \
        MEM_KEEP(exit.text*)                                            \

If you change .text.* to .text%* , this script will need a change, along wi=
th
other projects which use or adapt GNU ld's built-in linker script

  .text           :
  {
    *(.text.unlikely .text.*_unlikely .text.unlikely.*)
    *(.text.exit .text.exit.*)
    *(.text.startup .text.startup.*)
    *(.text.hot .text.hot.*)
    *(SORT(.text.sorted.*))
    *(.text .stub .text.* .gnu.linkonce.t.*)
    /* .gnu.warning sections are handled specially by elf.em.  */
    *(.gnu.warning)
  }

By default, -fno-unique-section-names produces '.text' instead of '.text.fo=
o'
in the normal -ffunction-sections case.

For PGO, -fno-unique-section-names produces '.text.hot.' instead of
'.text.hot.foo' in the normal -ffunction-sections case.

'.text.hot.' is an attempt to distinguish PGO caused 'hot' from a regular
functions named 'hot'.=