[Bug c/39456] New: Functions of a file in different named sections

[Bug c/39456] New: Functions of a file in different named sections

[etienne_lorrain at yahoo dot fr]

Just that I need to set each functions in a C file into different sections,
with section names I can link in different segments.
 That can be done with:
__attribute__ ((section ("sect1_fct1"))) void fct1 (void) {}
__attribute__ ((section ("sect1_fct2"))) void fct2 (void) {}
 But cannot unfortunately be done in a macro like:
__attribute__ ((section ("sect1_" __FUNCTION__ ))) void fct1 (void) {}

 It would be nice to have some way to do that, like:
__attribute__ ((section_prepend ("sect1_"))) void fct1 (void) {}
 so that a bad cut&paste somewhere do not create problems because
 a function is in the wrong section (by forgeting to change the
 concat'ed string).


-- 
           Summary: Functions of a file in different named sections
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: etienne_lorrain at yahoo dot fr
 GCC build triplet: all-all-all
  GCC host triplet: all-all-all
GCC target triplet: all-all-all


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39456

[Bug c/39456] Functions of a file in different named sections

[etienne_lorrain at yahoo dot fr]

------- Comment #1 from etienne_lorrain at yahoo dot fr  2009-03-19 16:33 -------
 Also, you cannot put function in another section and then
 use -ffunction-sections, i.e.:

etienne@gujin:~$ gcc --version
gcc (Debian 4.3.3-3) 4.3.3
Copyright (C) 2008 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

etienne@gujin:~$ cat tmp.c
__attribute__((section(".extracode"))) int fct1 (void) {
        return 1;
}
__attribute__((section(".extracode"))) int fct2 (void) {
        return 2;
}

etienne@gujin:~$ gcc -Os -fomit-frame-pointer -ffunction-sections -S tmp.c -o
tmp.s
etienne@gujin:~$ cat tmp.s
        .file   "tmp.c"
        .section        .extracode,"ax",@progbits
.globl fct1
        .type   fct1, @function
fct1:
        movl    $1, %eax
        ret
        .size   fct1, .-fct1
.globl fct2
        .type   fct2, @function
fct2:
        movl    $2, %eax
        ret
        .size   fct2, .-fct2
        .ident  "GCC: (Debian 4.3.3-3) 4.3.3"
        .section        .note.GNU-stack,"",@progbits
etienne@gujin:~$

 So you cannot use garbage collection in the linker...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39456

[Bug middle-end/39456] Functions of a file in different named sections

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
          Component|c                           |middle-end
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-04-16 20:51:34
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39456

[Bug middle-end/39456] Functions/variables of a file in different named sections

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2009-05-12 14:51 -------
*** Bug 40113 has been marked as a duplicate of this bug. ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sb-sf at users dot
                   |                            |sourceforge dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39456

[Bug middle-end/39456] Functions/variables of a file in different named sections

[etienne_lorrain at yahoo dot fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39456

--- Comment #4 from etienne_lorrain at yahoo dot fr 2012-01-03 09:53:59 UTC ---
Thanks for looking at my reports and happy new year!

I think the problem I had was the quoting and string concat, you need:
void fct2 (void) __attribute__((__section__("sect1_fct2"))) { return; }

The solution you give generates:
void fct1 (void) __attribute__((__section__(basesectfct1))) { return; }

You cannot give the compiler:
void fct2 (void) __attribute__((__section__("sect1_" "fct2"))) { return; }
because it would not concat the strings in this case (I did not re-check).

And:
#define function_def(base_section, funname, RET, ARGS) \
RET funname ARGS __attribute__((__section__(# base_section##funname)))
#define basesect sect1_
function_def(basesect, fct1, void, (void)) { return; }
will stringify #base_section before applying the ##

That was my problem...

[Bug middle-end/39456] Functions/variables of a file in different named sections

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39456

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-01-02 04:25:03 UTC ---
What about doing something like:
#define function_def(base_section, funname, RET, ARGS)
__attribute__((__section__(base_section ##funname))) RET funname ARGS

#define basesect "sect1_"

function_def(basesect, fct1, void, (void));

So you won't have a copy and paste error at all and it works without any real
changes to the compiler.