[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-11
     Ever Confirmed|0                           |1

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
   Last reconfirmed|2012-01-11 00:00:00         |2021-9-12

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note HOT_TEXT_SECTION_NAME/UNLIKELY_EXECUTED_TEXT_SECTION_NAME are no longer,
They are part of default_function_section now.


Note I suspect if we change the names in varasm.c, we need to change the
default linker script in binutils to do the same.

The big question is who defines a function named hot/unlikely/startup
(Note exit is already named as a standard C function which is for the exit so
that is ok).

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[hjl at lucon dot org]

------- Comment #6 from hjl at lucon dot org  2005-10-05 00:37 -------
I used libstdc++ as an example to show that it isn't unreasonable to have
.o files compiled with and without -fffunction-sections. Besides, on my system
there is a libstdc++.a. We can just use something like

#define HOT_TEXT_SECTION_NAME ".text..hot"
#define UNLIKELY_EXECUTED_TEXT_SECTION_NAME ".text..unlikely"

to avoid this issue.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[pinskia at gcc dot gnu dot org]

------- Comment #5 from pinskia at gcc dot gnu dot org  2005-10-04 23:14 -------
(In reply to comment #4)
> A library may be compiled with -ffunction-sections. It doesn't mean that all
> codes linked against that library have to use -ffunction-sections. For example,
> libstdc++ is compiled with -ffunction-sections. Do I have to use it for all
> programs linked against libstdc++? A better naming scheme can help this.

but libstdc++ is dynamic/shared library so it should not matter with respect
linking.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[hjl at lucon dot org]

------- Comment #4 from hjl at lucon dot org  2005-10-04 22:58 -------
A library may be compiled with -ffunction-sections. It doesn't mean that all
codes linked against that library have to use -ffunction-sections. For example,
libstdc++ is compiled with -ffunction-sections. Do I have to use it for all
programs linked against libstdc++? A better naming scheme can help this.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2005-10-04 22:41 -------
(In reply to comment #2)
> The problem is with -ffunction-sections, we may put a very big cold function in
> the .text.hot section and a very hot function in the .text.unlikely section. It
> defeats the whole purpose of .text.hot/.text.unlikely.

But -ffunction-sections disables the use hot/unlikely sections so what is the
problem?
Maybe you should not be mixing code compiled with and without
-ffunction-sections.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |minor
          Component|c                           |middle-end


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201

[Bug middle-end/24201] Potential problems with HOT_TEXT_SECTION_NAME

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2005-10-04 21:52 -------
I don't see why this is really a problem.  It only effects the gcing sections,
it just means you are not going to remove those functions when used with other
functions which are in the hold/cold section.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |middle-end


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24201