bar.c

extern int __attribute__((section(".data.foo"))) x;
int __attribute__((section(".text.foo"))) foo(int);

int __attribute__((section(".text.bar"), noinline)) bar(int y) {
  return foo(x + y);
}

extern "C" void _start(void) {
  volatile int i;
  volatile int v = bar(i);
}

building

flags="-O2 -W -Wall -fPIE -march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -ffreestanding -nostdlib -std=gnu++11 -fno-exceptions -flto -nostartfiles"

arm-none-eabi-g++ $flags -c -o foo.o foo.c
arm-none-eabi-g++ $flags -c -o bar.o bar.c
arm-none-eabi-g++ $flags foo.o bar.o -o test.elf
arm-none-eabi-objdump -d test.elf

foo.c

int __attribute__((section(".data.foo"))) a = 0;
int __attribute__((section(".data.foo"))) x = 0;
int __attribute__((section(".data.foo"))) b = 0;

int __attribute__((section(".text.foo"))) foo(int x) {
  return x;
}

output

test.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:	e52de004 	push	{lr}		; (str lr, [sp, #-4]!)
    8004:	e24dd00c 	sub	sp, sp, #12
    8008:	e59d0004 	ldr	r0, [sp, #4]
    800c:	eb000002 	bl	801c <_Z3bari.4016>
    8010:	e58d0000 	str	r0, [sp]
    8014:	e28dd00c 	add	sp, sp, #12
    8018:	e49df004 	pop	{pc}		; (ldr pc, [sp], #4)

0000801c <_Z3bari.4016>:
    801c:	e59f300c 	ldr	r3, [pc, #12]	; 8030 <_Z3bari.4016+0x14>
    8020:	e08f3003 	add	r3, pc, r3
    8024:	e5933000 	ldr	r3, [r3]
    8028:	e0800003 	add	r0, r0, r3
    802c:	e12fff1e 	bx	lr
    8030:	0000800c 	.word	0x0000800c