SBSFU Warray-bounds error when compiling data_init.c

[sute]

We are updating our buildtools to GNU Tools for STM32 11.3.rel1 for a new project that is using an existing SBSFU 2.4.0 based bootloader from a previous project that was using an older compiler. Trying to compile the bootloader gives following errors:

data_init.c: In function 'LoopCopyDataInit':                                                                                                                                                  
data_init.c:46:29: error: array subscript 'uint32_t {aka volatile long unsigned int}[0]' is partly outside array bounds of 'uint8_t[1]' {aka 'unsigned char[1]'} [-Werror=array-bounds]       
   46 |                 dst[i] = src[i];                                                                                                                                                      
      |                          ~~~^~~                                                                                                                                                       
data_init.c:36:24: note: while referencing '_sidata'                                                                                                                                          
   36 |         extern uint8_t _sidata asm("_sidata");                                                                                                                                        
      |                        ^~~~~~~                                                                                                                                                        
data_init.c:46:20: error: array subscript 'uint32_t {aka volatile long unsigned int}[0]' is partly outside array bounds of 'uint8_t[1]' {aka 'unsigned char[1]'} [-Werror=array-bounds]       
   46 |                 dst[i] = src[i];                                                                                                                                                      
      |                 ~~~^~~                                                                                                                                                                
data_init.c:82:24: note: while referencing '_sdata'                                                                                                                                           
   82 |         extern uint8_t _sdata asm("_sdata");                                                                                                                                          
      |                        ^~~~~~                                                                                                                                                         
data_init.c: In function 'LoopFillZerobss':                                                                                                                                                   
data_init.c:63:20: error: array subscript 'uint32_t {aka volatile long unsigned int}[0]' is partly outside array bounds of 'uint8_t[1]' {aka 'unsigned char[1]'} [-Werror=array-bounds]       
   63 |                 dst[i] = 0;                                                                                                                                                           
      |                 ~~~^~~                                                                                                                                                                
data_init.c:56:24: note: while referencing '_sbss'                                                                                                                                            
   56 |         extern uint8_t _sbss asm("_sbss");                                                                                                                                            
      |                        ^~~~~                                                                                                                                                          
data_init.c: In function 'LoopCleanDataInit':                                                                                                                                                 
data_init.c:89:20: error: array subscript 'uint32_t {aka volatile long unsigned int}[0]' is partly outside array bounds of 'uint8_t[1]' {aka 'unsigned char[1]'} [-Werror=array-bounds]
   89 |                 dst[i] = 0;
      |                 ~~~^~~
data_init.c:82:24: note: while referencing '_sdata'
   82 |         extern uint8_t _sdata asm("_sdata");
      |                        ^~~~~~

I don't really understand what "partly outside array bounds" means and is this a false positive. Google doesn't really help. I am able to disable the errors with "#pragma GCC diagnostic" macros around the functions in data_init.c. Is it safe to ignore these errors? I would really prefer to avoid updating SBSFU version.

[Jocelyn RICARD]

Hello @sute,

I could reproduce this compilation issue.

The problem comes from the type of the externals that is set as uint8_t instead of uint32_t.

Replacing in data_init.c, uint8_t by uint32_t in all extern references will solve the issue.

Best regards

Jocelyn

[sute]

Yes, this fixed the issue. Thanks! Still a bit confused about the warning though.

[sute]

After some testing, this modification actually seems to break SBSFU. It will compile fine but seems to just crash after starting and endlessly restart.