Compiler Warning onLL_CRC_FeedData16 and LL_SPI_TransmitData16

[Kurt Alber]

Posted on February 22, 2018 at 09:49

Hi! When I compile LL code from STM32CubeMX I get following warnings:

In file included from ../Inc/main.h:45:0,

                 from ../Inc/stm32f0xx_it.h:46,                 from ..\Src\stm32f0xx_it.c:35:../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_crc.h: In function 'LL_CRC_FeedData16':../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_crc.h:371:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]   *(uint16_t __IO *)(&CRCx->DR) = (uint16_t) InData;   ^In file included from ../Inc/main.h:55:0,                 from ../Inc/stm32f0xx_it.h:46,                 from ..\Src\stm32f0xx_it.c:35:../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_spi.h: In function 'LL_SPI_TransmitData16':../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_spi.h:1388:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]   *((__IO uint16_t *)&SPIx->DR) = TxData;

I don't use those functions therefore I comment them out, but should be fixed.

Tools:

STM32CubeMx 4.24.0 (STM32Cube V1.0)

TrueStudio V.9.0.0

Windows 7

Console Output:

**** Incremental Build of configuration Debug for project cameraApplication ****

Info: Internal Builder is used for buildarm-atollic-eabi-gcc -c -mthumb -mcpu=cortex-m0 -std=gnu11 -DUSE_FULL_LL_DRIVER -D__weak=__attribute__((weak)) -D__packed=__attribute__((__packed__)) -DSTM32F030x6 -I../Inc -IInc -ISrc -I../Drivers/STM32F0xx_HAL_Driver/Inc -I../Drivers/CMSIS/Device/ST/STM32F0xx/Include -I../Drivers/CMSIS/Include -Os -ffunction-sections -fdata-sections -g -fstack-usage -Wall -specs=nano.specs -o Src\hal.o ..\Src\hal.c arm-atollic-eabi-gcc -c -mthumb -mcpu=cortex-m0 -std=gnu11 -DUSE_FULL_LL_DRIVER -D__weak=__attribute__((weak)) -D__packed=__attribute__((__packed__)) -DSTM32F030x6 -I../Inc -IInc -ISrc -I../Drivers/STM32F0xx_HAL_Driver/Inc -I../Drivers/CMSIS/Device/ST/STM32F0xx/Include -I../Drivers/CMSIS/Include -Os -ffunction-sections -fdata-sections -g -fstack-usage -Wall -specs=nano.specs -o Src\stm32f0xx_it.o ..\Src\stm32f0xx_it.c In file included from ../Inc/main.h:45:0,                 from ..\Src\hal.c:2:../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_crc.h: In function 'LL_CRC_FeedData16':../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_crc.h:371:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]   *(uint16_t __IO *)(&CRCx->DR) = (uint16_t) InData;   ^arm-atollic-eabi-gcc -c -mthumb -mcpu=cortex-m0 -std=gnu11 -DUSE_FULL_LL_DRIVER -D__weak=__attribute__((weak)) -D__packed=__attribute__((__packed__)) -DSTM32F030x6 -I../Inc -IInc -ISrc -I../Drivers/STM32F0xx_HAL_Driver/Inc -I../Drivers/CMSIS/Device/ST/STM32F0xx/Include -I../Drivers/CMSIS/Include -Os -ffunction-sections -fdata-sections -g -fstack-usage -Wall -specs=nano.specs -o Src\epc611.o ..\Src\epc611.c In file included from ../Inc/main.h:55:0,                 from ..\Src\hal.c:2:../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_spi.h: In function 'LL_SPI_TransmitData16':../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_spi.h:1388:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]   *((__IO uint16_t *)&SPIx->DR) = TxData;   ^In file included from ../Inc/main.h:45:0,                 from ../Inc/stm32f0xx_it.h:46,                 from ..\Src\stm32f0xx_it.c:35:../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_crc.h: In function 'LL_CRC_FeedData16':../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_crc.h:371:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]   *(uint16_t __IO *)(&CRCx->DR) = (uint16_t) InData;   ^In file included from ../Inc/main.h:55:0,                 from ../Inc/stm32f0xx_it.h:46,                 from ..\Src\stm32f0xx_it.c:35:../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_spi.h: In function 'LL_SPI_TransmitData16':../Drivers/STM32F0xx_HAL_Driver/Inc/stm32f0xx_ll_spi.h:1388:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]   *((__IO uint16_t *)&SPIx->DR) = TxData;   ^arm-atollic-eabi-gcc -o cameraApplication.elf Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_crc.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_dma.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_exti.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_gpio.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_pwr.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_rcc.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_spi.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_tim.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_usart.o Drivers\STM32F0xx_HAL_Driver\Src\stm32f0xx_ll_utils.o Src\epc611.o Src\fsm.o Src\hal.o Src\main.o Src\spi.o Src\stm32f0xx_it.o Src\system_stm32f0xx.o Src\uart.o startup\startup_stm32f030x6.o -mthumb -mcpu=cortex-m0 -T../STM32F030F4_FLASH.ld -specs=nosys.specs -static -Wl,-Map=cameraApplication.map -Wl,--gc-sections -Wl,--defsym=malloc_getpagesize_P=0x80 -Wl,--start-group -lc -lm -Wl,--end-group -specs=nano.specs C:\TrueSTUDIO for STM32 9.0.0\ide\jre\bin\java -jar C:\TrueSTUDIO for STM32 9.0.0\Tools\arm-atollic-reports.jar sizeinfo list cameraApplication.elf Generate build reports...Print size information   text       data        bss        dec        hex    filename   5560         16       2688       8264       2048    cameraApplication.elfPrint size information doneGenerate listing fileOutput sent to: cameraApplication.listGenerate listing file doneGenerate build reports doneInfo: Parallel threads used: 3

[Tesla DeLorean]

Posted on February 23, 2018 at 14:11

GNU is being overly fussy, it is explicitly casting an otherwise 32-bit access on the memory to a 16-bit one (CRC depends on width of bus transaction). I remember another thread on this.

[Imen.D]

Posted on February 23, 2018 at 14:25

Hello,

Please refer to this discussion that can be helpful for you:

https://community.st.com/0D50X00009XkXPESA3

 

Best Regards,

Imen