Juan_David
Reputation: 136
linking newlib nano with arm-none-eabi gnu toolchain: undefined reference to __libc_init_array
Even though I have scrolled through another similar post regarding this topic, I have not yet managed to solve my issue.
I'm working on a bare metal development approach for stm32f411RE and I just got through the need of using embedded standard libraries (newlib nano) so then I proceeded to linking it to my project as well as as calling __libc_init_array() before main() in my Reset_Handler for the propper initialization of the standard library functions and here is where the problem arises.
Roughly speaking(pseudocode you might think) my startup file is as follows:
//Function prototypes
//main and Reset_Handler need to be inside extern
//in order to be recognized at the vector table
extern "C"{
int main(void);
void Reset_Handler(void);
void __libc_init_array(void);
}
vector_table={
(first address)STACK_POINTER,
(second address)Reset_Handler,
...
ISR routines
}
void Reset_Handler(void){
//call to __libc_init_array in order to initialize standard libraries functions
__libc_init_array();
//starting point of the program
main();
}
I get through the compilation and linking process successfully (no warnings, errors or anything) but the program fails to get to the main() function when I try to run it, in other words, it gets stuck at __libc_init_array();
When I run a debug session and look at the call stack this is what I get:
??@0xfffffce0 (Unknown Source:0)
<signal handler called>@0xfffffff9 (Unknown Source:0)
??@0x00000024 (Unknown Source:0)
And the program has not even reached main(). I guess it is obvious to say that setting a breakpoint is useless since the program does not even reaches main().
If I take __libc_init_array() out of the extern "C" I get the "__libc_init_array undefined reference" compilation error.
It is worth to say that my linker script as well as the startup and makefile were working like a charm on the bare metal approach, so the problem is not there, I mean, I just need to consider the appropriated flags for the linking process.
My project's structure is as following:
/My_project
-main.cpp
-file1.cpp
-file2.cpp
-startup_file.cpp
-linker_script.ld
-Makefile
-syscalls.c (requiered for newlib nano)
I'm building the object files with:
arm-none-eabi-g++ -c -mcpu=cortex-m4 -std=c++11 -o0 -fno-exceptions
with the exception of building syscall.c with:
arm-none-eabi-gcc -c -mcpu=cortex-m4 -std=c11 -o0 -fno-exceptions
then linking all the object files with:
-T stm32_ls.ld --specs=nano.specs -Wl, -Map=final.map
Here is the map after the linking:
Archive member included to satisfy reference by file (symbol)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-errno.o)
syscalls.o (__errno)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-exit.o)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o (exit)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-exit.o) (_global_impure_ptr)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-init.o)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o (__libc_init_array)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-memset.o)
/usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o (memset)
Memory Configuration
Name Origin Length Attributes
FLASH 0x0000000008000000 0x0000000000080000 xr
SRAM 0x0000000020000000 0x0000000000020000 xrw
*default* 0x0000000000000000 0xffffffffffffffff
Linker script and memory map
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crti.o
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o
LOAD stm32_startup.o
LOAD main.o
LOAD CONFIG.o
LOAD GPIO.o
LOAD LCD_16x2.o
LOAD USER_FUNCTIONS.o
LOAD syscalls.o
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libstdc++_nano.a
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libm.a
START GROUP
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/libgcc.a
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a
END GROUP
START GROUP
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/libgcc.a
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a
END GROUP
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtend.o
LOAD /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtn.o
.text 0x0000000008000000 0x1008
*(.isr_vector)
.isr_vector 0x0000000008000000 0x198 stm32_startup.o
*(.text)
.text 0x0000000008000198 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crti.o
.text 0x0000000008000198 0x70 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.text 0x0000000008000208 0x138 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o
0x0000000008000208 _stack_init
0x0000000008000290 _mainCRTStartup
0x0000000008000290 _start
.text 0x0000000008000340 0x90 stm32_startup.o
0x0000000008000340 Reset_Handler
0x00000000080003c8 Default_Handler
0x00000000080003c8 EXTI0_IRQHandler()
.text 0x00000000080003d0 0x124 main.o
0x00000000080003d0 enable_interrupt(IRQn_Struct)
0x0000000008000400 disable_interrupt(IRQn_Struct)
0x0000000008000434 EXTI15_10_IRQHandler()
0x0000000008000468 main
0x00000000080004a8 adc1_read()
0x00000000080004d8 adc1_start_convertion()
.text 0x00000000080004f4 0x24c CONFIG.o
0x00000000080004f4 system_clock_settings(char, boolean)
0x0000000008000630 EXTI_C13_config()
0x0000000008000684 ADC_PA1_Config()
0x00000000080006d8 HighSpeedConfig()
0x0000000008000704 TIM10_config_init()
.text 0x0000000008000740 0x56c GPIO.o
0x0000000008000740 GPIO_PORT::GPIO_PORT(char, int, int)
0x0000000008000740 GPIO_PORT::GPIO_PORT(char, int, int)
0x0000000008000778 GPIO_PORT::GPIO_PORT(char, int, int, int)
0x0000000008000778 GPIO_PORT::GPIO_PORT(char, int, int, int)
0x00000000080007b0 GPIO_PORT::set_pin_status(int)
0x0000000008000812 GPIO_PORT::read_pin_status()
0x0000000008000856 GPIO_PORT::toggle_pin_status()
0x0000000008000882 GPIO_PORT::pupd_selection(int)
0x0000000008000950 GPIO_PORT::pin_mode_input()
0x00000000080009aa GPIO_PORT::pin_mode_output()
0x0000000008000a04 GPIO_PORT::set_config()
0x0000000008000b3a GPIO_PORT::voltage_regulator_config()
0x0000000008000b5c GPIO_PORT::AHB1_clock_enable()
0x0000000008000bf4 GPIO_PORT::gpio_register_selector()
.text 0x0000000008000cac 0x0 LCD_16x2.o
.text 0x0000000008000cac 0x110 USER_FUNCTIONS.o
0x0000000008000cac delay_ms(int)
0x0000000008000d10 delay_us(int)
0x0000000008000d70 power(int, int)
.text 0x0000000008000dbc 0x202 syscalls.o
0x0000000008000dbc initialise_monitor_handles
0x0000000008000dc8 _getpid
0x0000000008000dd6 _kill
0x0000000008000df6 _exit
0x0000000008000e0a _read
0x0000000008000e44 _write
0x0000000008000e7c _close
0x0000000008000e92 _fstat
0x0000000008000eb0 _isatty
0x0000000008000ec4 _lseek
0x0000000008000edc _open
0x0000000008000ef6 _wait
0x0000000008000f14 _unlink
0x0000000008000f32 _times
0x0000000008000f48 _stat
0x0000000008000f66 _link
0x0000000008000f86 _fork
0x0000000008000f9c _execve
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-errno.o)
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-exit.o)
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-init.o)
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-memset.o)
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtend.o
.text 0x0000000008000fbe 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtn.o
*(.rodata)
*fill* 0x0000000008000fbe 0x2
.rodata 0x0000000008000fc0 0x24 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.rodata 0x0000000008000fe4 0x24 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtend.o
0x0000000008001008 . = ALIGN (0x4)
0x0000000008001008 _etext = .
.glue_7 0x0000000008001008 0x0
.glue_7 0x0000000008001008 0x0 linker stubs
.glue_7t 0x0000000008001008 0x0
.glue_7t 0x0000000008001008 0x0 linker stubs
.vfp11_veneer 0x0000000008001008 0x0
.vfp11_veneer 0x0000000008001008 0x0 linker stubs
.v4_bx 0x0000000008001008 0x0
.v4_bx 0x0000000008001008 0x0 linker stubs
.init 0x0000000008001008 0x18
.init 0x0000000008001008 0xc /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crti.o
0x0000000008001008 _init
.init 0x0000000008001014 0xc /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtn.o
.fini 0x0000000008001020 0x18
.fini 0x0000000008001020 0xc /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crti.o
0x0000000008001020 _fini
.fini 0x000000000800102c 0xc /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtn.o
.iplt 0x0000000008001038 0x0
.iplt 0x0000000008001038 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.text.__errno 0x0000000008001038 0x10
.text.__errno 0x0000000008001038 0x10 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-errno.o)
0x0000000008001038 __errno
.text.exit 0x0000000008001048 0x40
.text.exit 0x0000000008001048 0x40 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-exit.o)
0x0000000008001048 exit
.text.__libc_init_array
0x0000000008001088 0x80
.text.__libc_init_array
0x0000000008001088 0x80 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-init.o)
0x0000000008001088 __libc_init_array
.text.memset 0x0000000008001108 0x18
.text.memset 0x0000000008001108 0x18 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-memset.o)
0x0000000008001108 memset
.eh_frame 0x0000000008001120 0x4
.eh_frame 0x0000000008001120 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.eh_frame 0x0000000008001120 0x4 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtend.o
.ARM.extab 0x0000000008001124 0x0
.ARM.extab 0x0000000008001124 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o
.ARM.exidx 0x0000000008001124 0x8
.ARM.exidx 0x0000000008001124 0x8 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o
0x10 (size before relaxing)
.rodata._global_impure_ptr
0x000000000800112c 0x4
.rodata._global_impure_ptr
0x000000000800112c 0x4 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
0x000000000800112c _global_impure_ptr
.rel.dyn 0x0000000008001130 0x0
.rel.iplt 0x0000000008001130 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.data 0x0000000020000000 0x8 load address 0x0000000008001130
0x0000000020000000 _sdata = .
*(.data)
.data 0x0000000020000000 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crti.o
.data 0x0000000020000000 0x4 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
0x0000000020000000 __dso_handle
.data 0x0000000020000004 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o
.data 0x0000000020000004 0x0 stm32_startup.o
.data 0x0000000020000004 0x0 main.o
.data 0x0000000020000004 0x0 CONFIG.o
.data 0x0000000020000004 0x0 GPIO.o
.data 0x0000000020000004 0x0 LCD_16x2.o
.data 0x0000000020000004 0x0 USER_FUNCTIONS.o
.data 0x0000000020000004 0x4 syscalls.o
0x0000000020000004 environ
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-errno.o)
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-exit.o)
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-init.o)
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-memset.o)
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtend.o
.data 0x0000000020000008 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtn.o
0x0000000020000008 . = ALIGN (0x4)
0x0000000020000008 _edata = .
.init_array 0x0000000020000008 0x4 load address 0x0000000008001138
.init_array 0x0000000020000008 0x4 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.fini_array 0x000000002000000c 0x4 load address 0x000000000800113c
.fini_array 0x000000002000000c 0x4 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.igot.plt 0x0000000020000010 0x0 load address 0x0000000008001140
.igot.plt 0x0000000020000010 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.data._impure_ptr
0x0000000020000010 0x4 load address 0x0000000008001140
.data._impure_ptr
0x0000000020000010 0x4 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
0x0000000020000010 _impure_ptr
.data.impure_data
0x0000000020000014 0x60 load address 0x0000000008001144
.data.impure_data
0x0000000020000014 0x60 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
.bss 0x0000000020000074 0x24 load address 0x00000000080011a4
0x0000000020000074 _sbss = .
0x0000000020000074 __bss_start__ = _sbss
*(.bss)
.bss 0x0000000020000074 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crti.o
.bss 0x0000000020000074 0x1c /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtbegin.o
.bss 0x0000000020000090 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/crt0.o
.bss 0x0000000020000090 0x0 stm32_startup.o
.bss 0x0000000020000090 0x2 main.o
0x0000000020000090 sensor_value
.bss 0x0000000020000092 0x0 CONFIG.o
.bss 0x0000000020000092 0x0 GPIO.o
.bss 0x0000000020000092 0x0 LCD_16x2.o
.bss 0x0000000020000092 0x0 USER_FUNCTIONS.o
*fill* 0x0000000020000092 0x2
.bss 0x0000000020000094 0x4 syscalls.o
0x0000000020000094 __env
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-errno.o)
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-exit.o)
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-impure.o)
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-init.o)
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/../../../../arm-none-eabi/lib/libc_nano.a(lib_a-memset.o)
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtend.o
.bss 0x0000000020000098 0x0 /usr/bin/../lib/gcc/arm-none-eabi/10.3.1/crtn.o
0x0000000020000098 _ebss = .
0x0000000020000098 __bss_end__ = _ebss
0x0000000020000098 . = ALIGN (0x4)
0x0000000020000098 end = .
OUTPUT(final.elf elf32-littlearm)
LOAD linker stubs
I'm guessing, out of my ignorace, that name mangling is not the problem since __libc_init_array() is defined inside extern "C". Also, in the map file, I see only one symbol with the name __libc_init_array and it seems to be at the correct flash address.
Comments are valuable. Thanks for reading such a long post.
PD: linker script for whoever wants to read it:
ENTRY(Reset_Handler)
MEMORY
{
FLASH(rx):ORIGIN =0x08000000,LENGTH =512K
SRAM(rwx):ORIGIN =0x20000000,LENGTH =128K
}
SECTIONS
{
.text :
{
*(.isr_vector)
*(.text)
*(.rodata)
. = ALIGN(4);
_etext = .; /*end of section .text address*/
}>FLASH
.data :
{
_sdata = .;
*(.data)
. = ALIGN(4);
_edata = .;
}>SRAM AT> FLASH
.bss :
{
_sbss = .;
__bss_start__ = _sbss;
*(.bss)
_ebss = .;
__bss_end__ = _ebss;
. = ALIGN(4);
end = .;
}>SRAM
}
startup file:
#include <stdint.h>
/**aliased and external defined functions get their names mangled
*so one needs to avoid name mangling by treating those functions
*as if they were compiled in C.Thats done by extern **/
extern "C"{
int main(void);
void Reset_Handler(void);
void Default_Handler(void);
void __libc_init_array(void);
}
#define SRAM_START 0x20000000
#define SRAM_SIZE (128U*1024U) //128*1Kb
#define SRAM_END ((SRAM_START) + (SRAM_SIZE))
#define STACK_START SRAM_END
extern uint32_t _etext;
extern uint32_t _sdata;
extern uint32_t _edata;
extern uint32_t _sbss;
extern uint32_t _ebss;
//function prototyping
//function prototyping
__attribute__((weak, alias("Default_Handler")))void EXTI0_IRQHandler(void);
__attribute__((weak, alias("Default_Handler")))void EXTI15_10_IRQHandler(void);
uint32_t(* const vectors[]) __attribute__((section(".isr_vector"))) ={
(uint32_t*)STACK_START, /* 0x000 Stack Pointer */
(uint32_t*)Reset_Handler, /* 0x004 Reset */
};
void Reset_Handler(void)
{
//copy .data section to SRAM
uint32_t size = (uint32_t)&_edata - (uint32_t)&_sdata;
uint8_t *pDst = (uint8_t*)&_sdata; //sram
uint8_t *pSrc = (uint8_t*)&_etext; //source point comes from flash memory that is end of flash
for(uint32_t i =0 ; i < size ; i++)
{
*pDst++ = *pSrc++;
}
//copy .bss section to SRAM
size = (uint32_t)&_ebss - (uint32_t)&_sbss;
pDst = (uint8_t*)&_sbss; //sram
for(uint32_t i =0 ; i < size ; i++)
{
*pDst++ = 0;
}
__libc_init_array();
main();
}
void Default_Handler(void)
{
while(1);
}
Upvotes: 1
Views: 4881
Answers (1)
Tom V
Reputation: 5510
First of all, __libc_init_array() belongs inside extern "C". The map file you have above has it correct: it gets pulled in from libc_nano.a(lib_a-init.o).
This is not really the problem though. In your vector table, you have Reset_Handler where you should have the initial value of the stack pointer, and main where you should have the reset handler. main should never be in the vector, it is called by the reset handler as a normal function, not through the vector.
The crash you are having is most likely because you don't have a correct stack pointer, and the code is trying to use the stack.
Also, the first thing you do in your reset handler is call __libc_init_array. This is wrong. You need to (at least) copy the initialized data and zero the bss section first. If you are following the CMSIS pattern then you also need to call SystemInit. See the sample startup code and linker scripts in the STM32CubeF4 package.
EDIT: The above problems are in your pseudocode; the code doesn't match the pseudocode and doesn't have the above problems.
The next problem is that you have deleted half of the standard linker script. Try looking at the source of __libc_init_array to see what it needs. It needs the init array sections etc.
Here is an example with them in:
.init :
{
KEEP (*(SORT_NONE(.init)))
}
>FLASH
.text :
{
*(.text .text.* .stub .gnu.linkonce.t.*)
}
>FLASH
.fini :
{
KEEP (*(SORT_NONE(.fini)))
}
>FLASH
.preinit_array :
{
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);
}
>FLASH
.init_array :
{
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)))
KEEP (*(.init_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .ctors))
PROVIDE_HIDDEN (__init_array_end = .);
}
>FLASH
.fini_array :
{
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT_BY_INIT_PRIORITY(.fini_array.*) SORT_BY_INIT_PRIORITY(.dtors.*)))
KEEP (*(.fini_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .dtors))
PROVIDE_HIDDEN (__fini_array_end = .);
}
>FLASH
.ctors :
{
KEEP (*crtbegin.o(.ctors))
KEEP (*crtbegin?.o(.ctors))
KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .ctors))
KEEP (*(SORT(.ctors.*)))
KEEP (*(.ctors))
}
>FLASH
.dtors :
{
KEEP (*crtbegin.o(.dtors))
KEEP (*crtbegin?.o(.dtors))
KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .dtors))
KEEP (*(SORT(.dtors.*)))
KEEP (*(.dtors))
}
>FLASH
Upvotes: 1
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