__attribute__((naked)) doesn't bx lr

[Hedley Rainnie]

All was good wrt reg allocation, just missing the bx back at the end of the function. Result is it walks in to the next function (bad).

 __attribute__((naked))
void myfunc()
{
   static int x=1;
   x++;
}

gcc version 5.3.1 20160307 (release) [ARM/embedded-5-branch revision 234589] (GN
U Tools for ARM Embedded Processors)

arm-none-eabi-gcc -O2 -c minimal.c
arm-none-eabi-objdump -d minimal.o

minimal.o: file format elf32-littlearm

Disassembly of section .text:

00000000 <myfunc>:
   0: e59f2008 ldr r2, [pc, #8] ; 10 <myfunc+0x10>
   4: e5923000 ldr r3, [r2]
   8: e2833001 add r3, r3, #1
   c: e5823000 str r3, [r2]
  10: 00000000 .word 0x00000000

tnx

Hedley

[Hedley Rainnie (hedley-6)]

Also, it was compiled on an ubuntu 16.04 LTS machine.

uname -r
4.4.0-22-generic

[Hedley Rainnie (hedley-6)]

Never mind. This is a mistake in TI's code (they should not be using this). No epilogue generated as per the docs.

tnx

H.