rand() function uses 5K space

[eos1d3]

Describe the set-up

• STM32G030C8Tx
• STM32CUBEIDE 1.10.1, STM32Cube FW_G0 V1.6.1

Describe the bug When using rand() function, the project size increases around 5K. But the actual code is very small when copy sand() and rand() from gcc code.

How To Reproduce

1. add #include <stdlib.h>

2. Callsrand()and also rand()

3. compile the project to see the size

4. remove srand() and rand() and compile to compare the size

Additional context I found vprintf, printf, putc, puts... are linked. But none of them are used in the project. Once the random functions are removed, all of these are gone.

[HBOSTM]

Hello @eos1d3 ,

From my side there is no problem in the project size with random functions, Would you please give us more details about how you got this issue? And share the code you have used to reproduce this issue.

Best Regards,

[eos1d3]

Hi,

Just use STM32CubeIDE to create a empty project. I use STM32G030C8T.

Add the header:

#include "stdlib.h"

And the rand() function in main loop:

rand();

Comment out the 'rand()' call to compare the code size.

With Release config:

No rand() call:

   text    data     bss     dec     hex filename
   2912      20    1572    4504    1198 stm32_exe.elf

Has rand() call:

arm-none-eabi-objdump -h -S  stm32_exe.elf  > "stm32_exe.list"
   text    data     bss     dec     hex filename
   7904     120    1592    9616    2590 stm32_exe.elf

My IDE version: STM32 Cube FW_G0 V1/6/1 STM32CubeIDE Version: 1.11.2 for Mac (previous version also has the same issue) Project settings: everything is default

You can clone this to test https://github.com/eos1d3/stm32test

I make my own copy of srand and rand with the same gcc implementation, it is just few hundred bytes.

[eos1d3]

No fix?

Actually I use the following and to avoid calling system library to fix the problem

void Random::srand(unsigned int seed) {
    next = seed;
}

int Random::rand(void) // RAND_MAX assumed to be 32767
        {
    next = next * 1103515245 + 12345;
    return (unsigned int) (next / 65536) % 32768;
}

[HBOSTM]

Hi @eos1d3,

Thank you again for this contribution, this point has been reported to our development teams. I will get back to you as soon as I have any updates.

Best Regards,

[HBOSTM]

ST Internal Reference: 153499

[HBOSTM]

Hi @eos1d3 ,

The extra amount of code is due to newlib-nano reentrancy checking, you can either use standard newlib in that particular case rand() will be smaller and not import printf, etc... but the overall size of the lib contribution will be bigger, or you can keep using nano and define the assert function like this:

void __assert_func(const char , int, const char , const char *) { while(1); }

Which will avoid pulling printf symbols, and don't forget to add -Wl,--gc-sections flags to remove unused symbols (if you didn't).

Best Regards, Houssine

[HBOSTM]

Hello @eos1d3,

Please allow me to close this thread as no activity. You may reopen it at anytime if you have any details to share with us in order to help you to solve this issue. Thank you for your comprehension.

With regards,