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RIOT/makefiles/arch/avr8.inc.mk
Marian Buschsieweke b86366e34e
makefiles/toolchain: Fix incorrect assumptions on address space layout
GCC 12 gives out of bounds warnings when the resulting address is out
of bounds of what GCC assumes to be the valid address space. It seems
that by default the address 0x0 is not considered valid (which would
be a NULL pointer and typically not mapped in a userspace behind an MMU
scenario), but in fact is valid on bare metal hardware. At least on
AVR and MSP430 this needs to be set. On many Cortex M MCUs 0x0 is also
a valid address (e.g. often the flash is mapped there), but seemingly
for them `--param=min-pagesize=0` is already the default. In any case,
it won't hurt to set it explicit for them as well.
2023-05-08 15:42:40 +02:00

44 lines
1.6 KiB
Makefile

# Target architecture for the build. Use avr if you are unsure.
TARGET_ARCH_AVR ?= avr
TARGET_ARCH ?= $(TARGET_ARCH_AVR)
ifeq (atxmega,$(CPU))
ifeq (,$(CPU_MODEL))
$(error CPU_MODEL must have been defined by the board Makefile.features)
endif
CFLAGS_CPU ?= -mmcu=$(CPU_MODEL) $(CFLAGS_FPU)
else
CFLAGS_CPU ?= -mmcu=$(CPU) $(CFLAGS_FPU)
endif
CFLAGS_LINK = -ffunction-sections -fdata-sections -fno-builtin -fshort-enums
CFLAGS_DBG ?= -ggdb -g3
CFLAGS_OPT ?= -Os
# Use of __flash requires gnu11 instead of c11
CFLAGS += -std=gnu11
CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
ASFLAGS += $(CFLAGS_CPU) $(CFLAGS_DBG)
LINKFLAGS += $(CFLAGS_CPU) $(CFLAGS_DBG) $(CFLAGS_OPT) -static -lgcc -e reset_handler -Wl,--gc-sections
LINKFLAGS += -L$(RIOTCPU)/avr8_common/ldscripts
LINKFLAGS += -T$(LINKER_SCRIPT)
# Use ROM_LEN and RAM_LEN during link
$(if $(ROM_LEN),,$(error ROM_LEN is not defined))
$(if $(RAM_LEN),,$(error RAM_LEN is not defined))
LINKFLAGS += $(LINKFLAGPREFIX)--defsym=__TEXT_REGION_LENGTH__=$(ROM_LEN)$(if $(ROM_RESERVED),-$(ROM_RESERVED))
LINKFLAGS += $(LINKFLAGPREFIX)--defsym=__DATA_REGION_LENGTH__=$(RAM_LEN)
LINKFLAGS += $(LDSCRIPT_EXTRA)
ifeq ($(LTO),1)
# avr-gcc <4.8.3 has a bug when using LTO which causes a warning to be printed always:
# '_vector_25' appears to be a misspelled signal handler [enabled by default]
# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59396
LINKFLAGS += -Wno-error
endif
OPTIONAL_CFLAGS_BLACKLIST += -Wformat-overflow
OPTIONAL_CFLAGS_BLACKLIST += -Wformat-truncation
OPTIONAL_CFLAGS_BLACKLIST += -gz