Hi all:
I have been noticing that a function that is not used by any module in
program gets linked anyway, occupying some precious amount of memory.
Suppose that you were sharing a common module but you only needed some
functions of it. Is there a way to avoid linking all the unused
functions?
I am also posting the output of msp430-objdump with an example of the
situation:
tst_unreachable_code.elf: file format elf32-msp430
Disassembly of section .text:
00003100 <__init_stack>:
3100: 31 40 00 31 mov #12544, r1 ;#0x3100
00003104 <__low_level_init>:
3104: b2 40 80 5a mov #23168, &0x0120 ;#0x5a80
3108: 20 01
0000310a <__do_clear_bss>:
310a: 3f 40 00 00 mov #0, r15 ;#0x0000
310e: 0f 93 cmp #0, r15 ;r3 As==00
3110: 04 24 jz $+10 ;abs 0x311a
3112: 1f 83 dec r15 ;
3114: cf 43 00 11 mov.b #0, 4352(r15);r3 As==00
3118: fc 23 jnz $-6 ;abs 0x3112
0000311a <__do_copy_data>:
311a: 3f 40 00 00 mov #0, r15 ;#0x0000
311e: 0f 93 cmp #0, r15 ;r3 As==00
3120: 05 24 jz $+12 ;abs 0x312c
3122: 2f 83 decd r15 ;
3124: 9f 4f 4c 31 mov 12620(r15),4352(r15);
3128: 00 11
312a: fb 23 jnz $-8 ;abs 0x3122
0000312c <__jump_to_main>:
312c: 30 40 3a 31 br #0x313a ;
00003130 <__ctors_end>:
3130: 80 00 .word 0x0080; ????
3132: 4a 31 jn $+662 ;abs 0x33c8
#include <io.h>
00003134 <foo>:
void foo(void)
{
/* A function not used by anybody in program but,
* however, is linked anyway, wasting ROM space.
*/
P1OUT ^= 0x02; /* Toggle P1.1 */
3134: e2 e3 21 00 xor.b #2, &0x0021 ;r3 As==10
}
3138: 30 41 ret
0000313a <main>:
int main (void)
{
313a: 31 40 00 31 mov #12544, r1 ;#0x3100
WDTCTL=WDTPW+WDTHOLD; /* Stop watchdog */
313e: b2 40 80 5a mov #23168, &0x0120 ;#0x5a80
3142: 20 01
while(1)
{
P1OUT ^= 0x01; /* Toggle P1.0 */
3144: d2 e3 21 00 xor.b #1, &0x0021 ;r3 As==01
3148: fd 3f jmp $-4 ;abs 0x3144
0000314a <_unexpected_>:
}
}// end main
314a: 00 13 reti
Disassembly of section .vectors:
0000ffc0 <InterruptVectors>:
ffc0: 30 31 jn $+610 ;abs 0x222
ffc2: 30 31 jn $+610 ;abs 0x224
ffc4: 30 31 jn $+610 ;abs 0x226
ffc6: 30 31 jn $+610 ;abs 0x228
ffc8: 30 31 jn $+610 ;abs 0x22a
ffca: 30 31 jn $+610 ;abs 0x22c
ffcc: 30 31 jn $+610 ;abs 0x22e
ffce: 30 31 jn $+610 ;abs 0x230
ffd0: 30 31 jn $+610 ;abs 0x232
ffd2: 30 31 jn $+610 ;abs 0x234
ffd4: 30 31 jn $+610 ;abs 0x236
ffd6: 30 31 jn $+610 ;abs 0x238
ffd8: 30 31 jn $+610 ;abs 0x23a
ffda: 30 31 jn $+610 ;abs 0x23c
ffdc: 30 31 jn $+610 ;abs 0x23e
ffde: 30 31 jn $+610 ;abs 0x240
ffe0: 30 31 interrupt service routine at 0x3130
ffe2: 30 31 interrupt service routine at 0x3130
ffe4: 30 31 interrupt service routine at 0x3130
ffe6: 30 31 interrupt service routine at 0x3130
ffe8: 30 31 interrupt service routine at 0x3130
ffea: 30 31 interrupt service routine at 0x3130
ffec: 30 31 interrupt service routine at 0x3130
ffee: 30 31 interrupt service routine at 0x3130
fff0: 30 31 interrupt service routine at 0x3130
fff2: 30 31 interrupt service routine at 0x3130
fff4: 30 31 interrupt service routine at 0x3130
fff6: 30 31 interrupt service routine at 0x3130
fff8: 30 31 interrupt service routine at 0x3130
fffa: 30 31 interrupt service routine at 0x3130
fffc: 30 31 interrupt service routine at 0x3130
fffe: 00 31 interrupt service routine at 0x3100
Thank you very much for your attention.
Alex
