[Bug c/37506] attribute section is not working with constant strings

[nm127 at freemail dot hu]

--- Comment #6 from nm127 at freemail dot hu  2008-09-14 07:14 ---
(In reply to comment #5)
 This is all expected, if you want a string constant to be in a different
 section, you need to put there your self by using a variable.

So the __attribute__ __section__ modifier is not recursively applied to all
child element?

If the __attribute__ __section__ is not recursive shouldn't it be possible to
specify explicitly this modifier for the child elements something like z and
w  in comment #4?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506

[Bug c/37506] attribute section is not working with constant strings

[brian at dessent dot net]

--- Comment #7 from brian at dessent dot net  2008-09-14 07:54 ---
Subject: Re:  attribute section is not working with constant strings


If you want a struct containing a pointer to a string in a specified
section, then:

char str[] __attribute__ ((__section__(.xxx_section))) = foo;

struct foo {
  char *p
} var = { str };


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506

[Bug c/37506] attribute section is not working with constant strings

[pinskia at gmail dot com]

--- Comment #1 from pinskia at gmail dot com  2008-09-13 09:49 ---
Subject: Re:   New: attribute section is not working with constant strings



Sent from my iPhone

On Sep 13, 2008, at 2:04 AM, nm127 at freemail dot hu
[EMAIL PROTECTED] 
  wrote:

 With the __attribute__ __section__ it is possible to allocate  
 variables to
 different section than the default (
 http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html ). In  
 case of the
 following source code I would achieve to allocate both foo bar and  
 Hello
 World! strings into the .xxx_section section:

 char x[] __attribute__ ((__section__(.xxx_section))) = foo bar;
 char* y __attribute__ ((__section__(.xxx_section))) = Hello  
 World!;

 int main() {
return 0;
 }

 However, with gcc version 4.3.1 (Debian 4.3.1-9) only the foo bar  
 string is
 stored in .xxx_section:

 $ objdump -s a.out

 a.out: file format elf32-i386
 [...]
 Contents of section .rodata:
 8048448 0300 01000200 48656c6c 6f20576f  Hello Wo
 8048458 726c6421 00  rld!.
 [...]
 Contents of section .xxx_section:
 8049568 666f6f20 62617200 50840408   foo bar.P...


 -- 
   Summary: attribute section is not working with constant  
 strings
   Product: gcc
   Version: unknown
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: nm127 at freemail dot hu
 GCC build triplet: 4.3.1
 GCC target triplet: i486-linux-gnu


 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506

[Bug c/37506] attribute section is not working with constant strings

[nm127 at freemail dot hu]

--- Comment #2 from nm127 at freemail dot hu  2008-09-13 13:59 ---
This problem maybe related to bug #192.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506

[Bug c/37506] attribute section is not working with constant strings

[pinskia at gcc dot gnu dot org]

--- Comment #3 from pinskia at gcc dot gnu dot org  2008-09-14 04:45 ---
char* y __attribute__ ((__section__(.xxx_section))) = Hello World!;

That only puts the pointer variable y into that section and not the string. 
The correct way is do like what you do for x.


-- 

pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution||INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506

[Bug c/37506] attribute section is not working with constant strings

[nm127 at freemail dot hu]

--- Comment #4 from nm127 at freemail dot hu  2008-09-14 05:32 ---
(In reply to comment #3)
 char* y __attribute__ ((__section__(.xxx_section))) = Hello World!;
 
 That only puts the pointer variable y into that section and not the string. 

Exatly that is my problem. So the pointer variable y goes to section
.xxx_section, but the actual string not. And I do not know any possibility to
specify that the Hello World! string should also go to .xxx_section.

For example I expect that in case of the following two lines the Hello World!
string itself should be stored in section .xxx_section:

char* z = __attribute__ ((__section__(.xxx_section))) Hello World!;
char* w = Hello World! __attribute__ ((__section__(.xxx_section)));

What I get for both lines is an error message:

$ gcc -Wall test.c  
test.c:5: error: expected expression before '__attribute__'
test.c:6: error: expected ',' or ';' before '__attribute__'

Also, the problem gets complicated when a complete structure is initialized and
it has some string fields:

typedef struct {
int x;
int y;
char* str;
} s;

s a __attribute__ ((__section__(.xxx_section))) = {
0x11223344,
0x55667788,
string of the initialized struct
};

int main() {
return 0;
}

Now we get the following sections:

$ objdump -s a.out

a.out: file format elf32-i386

[...]
Contents of section .rodata:
 8048448 0300 01000200 73747269 6e67206f  string o
 8048458 66207468 6520696e 69746961 6c697a65  f the initialize
 8048468 64207374 72756374 00 d struct.   
[...]
Contents of section .xxx_section:
 804957c 44332211 88776655 50840408   D3..wfUP...

My expectation is that if I specify that the structure should be stored in
.xxx_section than the string itself should also be stored in .xxx_section.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506

[Bug c/37506] attribute section is not working with constant strings

[pinskia at gcc dot gnu dot org]

--- Comment #5 from pinskia at gcc dot gnu dot org  2008-09-14 05:36 ---
This is all expected, if you want a string constant to be in a different
section, you need to put there your self by using a variable.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37506