Adding assembly after end of functions in GCC-3.4

[Etienne Lorrain <etienne_lorrain at yahoo dot fr>]

  Hello,

  I was wondering, now that the functions are completely
 re-ordered with GCC-3.4, and so you can no more put asm ("") in
 between functions, if it would (undocumentely) work to put an
 asm("") in between the last return of a function and the closing
 brace of the function. I could use it to place some assembler
 instructions or directives after the last "ret" assembly instruction.

  The two uses I can see is to know the size in bytes of a function
 and to simulate the still uninplemented longcall/long_call/far
 function attribute for ia32 (i.e. terminating the function
 by "lret"/"lretw" - in Intel terms a "far return" poping %ip and %cs)
 Other people may find other uses to put assembly there (switching
 section with the assembly " .previous " operation).

  Well, it does not work (the volatile assembly is not inserted)
 and it does not generate any warning neither...

  Etienne.

[etienne@localhost gujin]$ cat asm.c
void do_something (void);
extern char sizeof_fct[];
// extern void sizeof_fct[]; // would be more meaningfull?
 
void fct (void)
{
        do_something();
        return;
        asm volatile (" sizeof_fct = fct - . \n");
}
 
void another (void)
{ asm (".macro ret \n lretw \n .endm \n"); {
        do_something();
        return;
} asm volatile (".purgem ret \n"); }

[etienne@localhost gujin]$ ../toolchain-3.4/bin/gcc -Wall -w -O -S asm.c -o
asm.s
[etienne@localhost gujin]$ cat asm.s
        .file   "asm.c"
        .text
.globl fct
        .type   fct, @function
fct:
        pushl   %ebp
        movl    %esp, %ebp
        subl    $8, %esp
        call    do_something
        leave
        ret
        .size   fct, .-fct
.globl another
        .type   another, @function
another:
        pushl   %ebp
        movl    %esp, %ebp
        subl    $8, %esp
#APP
        .macro ret
 lretw
 .endm
 
#NO_APP
        call    do_something
        leave
        ret
        .size   another, .-another
        .section        .note.GNU-stack,"",@progbits
        .ident  "GCC: (GNU) 3.4.0 20040121 (prerelease)"
------------ the macro ret is still defined here,
------------ the (possibly) following function will have
------------ problems.



	

	
		
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