Tomek,
Using arm-gcc-none-eabi-gcc-14.2.1 from the STMicroelectronics Arduino
toolchain "arm-none-eabi-gcc-14.2.1 (xPack GNU Arm Embedded GCC x86_64)
14.2.1 20241119" I see the _same_ behavior where no format warnings are
generated without removing linemarkers from the preprocessed source.
The following tiny testcase (copmiled using "-Wall -c test.c" ) elicits
the format warning from either compiler version as expected:
typedef __UINT32_TYPE__ uint32_t;
extern uint32_t getreg32(uint32_t addr);
extern void setreg32(uint32_t addr, uint32_t value);
extern void syslog(int priority, const char *fmt, ...) \
__attribute__((__format__(__printf__, 2, 3)));
void testcase(uint32_t addr, uint32_t value)
{
syslog(6, "%s: " "%08x[%08x]->%08x\n", __FUNCTION__, addr, getreg32(addr),
value);
setreg32(addr, value);
}
The question I have is why doesn't building Nuttx (with DEBUG_IRQ_INFO
enabled) for arm (nucleo-h743zi2:jumbo in my case) cause stm32_irq.c to
show the same format warning??
On 2/22/26 20:05, Tomek CEDRO wrote:
What happens on GCC 14.2? I know this one is preferred :-)
--
CeDeROM, SQ7MHZ,http://www.tomek.cedro.info
On Sun, Feb 22, 2026 at 11:12 PM Peter Barada<[email protected]> wrote:
This is _really_ weird. I'm seeing what looks (to me) to be a bug in
arm-none-eabig-gcc where it _may_ generate format warnings (or not) when
run over functionally equivalent source using same compilation options.
I'm trying to understand why a syslog call using a format of "%08x" and
an argument of uint32_t doesn't cause a format warning when built using
arm-none-eabi-gcc (version 13.2.1 20231009) on my Ubuntu machine.
I configured nuttx fornucelo-h743zi2:jumbo, tweaked the configuration
to enable DEBUG_IRQ_INFO, and built with V=1 to get the compiler command
line for arch/arm/src/chip/stm32_irq.c:
tools/configure.sh -l nucleo-h743zi2jumbo
kconfig-tweak --file .config -e DEBUG_IRQ_INFO
make V=1 -j $(nproc)
Then chdir into arch/arm/src and generate preprocessed source of
chip/stm32_irq.c into /tmp/stm32_irq.c using the complication command
from the build:
cd arch/arm/src
# setup BASE_DIR to root of nuttx tree
BASE_DIR=/home/peter/git/nuttx/github/nucleo-h743zi2-warnings/nuttx
# setup COMPILER_OPTIONS for what gets passed to gcc
COMPILER_OPTIONS="-Wstrict-prototypes -Wno-attributes -Wno-unknown-pragmas" \
" -Wno-psabi -Os -fno-strict-aliasing -fomit-frame-pointer" \
" --param=min-pagesize=0 -fno-common -Wall -Wshadow -Wundef" \
" -ffunction-sections -fdata-sections "-g" -mlittle-endian" \
" -march=armv7e-m -mtune=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard" \
" -mthumb -Wa,-mthumb -Wa,-mimplicit-it=always -isystem"
# Generate /tmp/stm32_irq.c from chip/stm32_irq.c
arm-none-eabi-gcc -E $COMPILER_OPTIONS $BASE_DIR/include -D__NuttX__ \
-DNDEBUG -D__KERNEL__ -I $BASE_DIR/arch/arm/src/chip \
-I $BASE_DIR/arch/arm/src/common -I $BASE_DIR/arch/arm/src/armv7-m \
-I $BASE_DIR/sched chip/stm32_irq.c -o /tmp/stm32_irq.c
# Compile the result file using same compiler options:
arm-none-eabi-gcc -E $COMPILER_OPTIONS $BASE_DIR/include -D__NuttX__ \
-DNDEBUG -D__KERNEL__ -I $BASE_DIR/arch/arm/src/chip \
-I $BASE_DIR/arch/arm/src/common -I $BASE_DIR/arch/arm/src/armv7-m \
-I $BASE_DIR/sched chip/stm32_irq.c -o /tmp/stm32_irq.c
# So far no errors (yes, get a preprocessow warning, can ignore)
The above should just generate a preprofcessing warning. Now it gets
strange:
# Remove _all_ the preprocessor generated linemarkers and compile again:
sed -ie '/^#/d' /tmp/stm32_irq.c
arm-none-eabi-gcc -E $COMPILER_OPTIONS $BASE_DIR/include -D__NuttX__ \
-DNDEBUG -D__KERNEL__ -I $BASE_DIR/arch/arm/src/chip \
-I $BASE_DIR/arch/arm/src/common -I $BASE_DIR/arch/arm/src/armv7-m \
-I $BASE_DIR/sched chip/stm32_irq.c -o /tmp/stm32_irq.c
And now I see format warnings (here's the first):
/tmp/stm32_irq.c: In function 'stm32_dumpnvic':
/tmp/stm32_irq.c:4875:12: warning: format '%x' expects argument of type
'unsigned int', but argument 4 has type 'uint32_t' {aka 'long unsigned int'}
[-Wformat=]
4875 | syslog(6, "%s: "
| ^~~~~~
......
4878 | getreg32((0xe000e000 + 0x0d04)), getreg32((0xe000e000 + 0x0d08))
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| |
| uint32_t {aka long unsigned int}
/tmp/stm32_irq.c:4876:20: note: format string is defined here
4876 | " INTCTRL: %08x VECTAB: %08x\n"
| ~~~^
| |
| unsigned int
| %08lx
Could someone who builds stm32 on Ubuntu try out above commands
(changing BASE_DIR to match your tree) and tell me if you see same
results where format warnings magically appear? Any ideas why gcc
generates format warnings over same source - only after removing all the
preprocessor linemarkers?
Thanks in advance!
--
Peter Barada
[email protected]
--
Peter Barada
[email protected]
