buildroot/toolchain/toolchain-wrapper.mk
Atharva Lele 71d6901454 toolchain/toolchain-wrapper: handle __{BASE_,}FILE__ macro for reproducibility
Many tools use __FILE__ or __BASE_FILE__ for debugging and both
capture the build path. This results in non-reproducible images when
building in different directories.

If the config uses GCC 8 or above, we use -ffile-prefix-map=old=new
and let gcc take care of the path remapping in __FILE__. Since GCC
versions before v8 did not have this feature, we use an empty string
in that case, and disable the builtin-macro-redefined warning which
would otherwise trigger and cause build issues with -Werror.

Signed-off-by: Atharva Lele <itsatharva@gmail.com>
[Thomas:
 - as suggested by Arnout, use the empty string for the __FILE__ and
   __BASE_FILE__ value
 - as suggested by Romain, also handle __BASE_FILE__ in addition to
   __FILE__
 - pass -Wno-builtin-macro-redefined to avoid build errors when
   -Werror is passed]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
2020-01-06 23:24:52 +01:00

82 lines
2.4 KiB
Makefile

################################################################################
#
# definition of the toolchain wrapper build commands
#
################################################################################
# We use --hash-style=both to increase the compatibility of the generated
# binary with older platforms, except for MIPS, where the only acceptable
# hash style is 'sysv'
ifeq ($(findstring mips,$(HOSTARCH)),mips)
TOOLCHAIN_WRAPPER_HASH_STYLE = sysv
else
TOOLCHAIN_WRAPPER_HASH_STYLE = both
endif
TOOLCHAIN_WRAPPER_ARGS = $($(PKG)_TOOLCHAIN_WRAPPER_ARGS)
TOOLCHAIN_WRAPPER_ARGS += -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
TOOLCHAIN_WRAPPER_OPTS = \
$(ARCH_TOOLCHAIN_WRAPPER_OPTS) \
$(call qstrip,$(BR2_SSP_OPTION)) \
$(call qstrip,$(BR2_TARGET_OPTIMIZATION))
ifeq ($(BR2_REPRODUCIBLE),y)
TOOLCHAIN_WRAPPER_OPTS += -Wl,--build-id=none
ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_8),y)
TOOLCHAIN_WRAPPER_OPTS += -ffile-prefix-map=$(BASE_DIR)=buildroot
else
TOOLCHAIN_WRAPPER_OPTS += -D__FILE__=\"\" -D__BASE_FILE__=\"\" -Wno-builtin-macro-redefined
endif
endif
# We create a list like '"-mfoo", "-mbar", "-mbarfoo"' so that each flag is a
# separate argument when used in execv() by the toolchain wrapper.
TOOLCHAIN_WRAPPER_ARGS += \
-DBR_ADDITIONAL_CFLAGS='$(foreach f,$(TOOLCHAIN_WRAPPER_OPTS),"$(f)"$(comma))'
ifeq ($(BR2_CCACHE),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE
endif
ifeq ($(BR2_x86_x1000),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR_OMIT_LOCK_PREFIX
endif
# Avoid FPU bug on XBurst CPUs
ifeq ($(BR2_mips_xburst),y)
# Before gcc 4.6, -mno-fused-madd was needed, after -ffp-contract is
# needed
ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_4_6),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR_FP_CONTRACT_OFF
else
TOOLCHAIN_WRAPPER_ARGS += -DBR_NO_FUSED_MADD
endif
endif
ifeq ($(BR2_CCACHE_USE_BASEDIR),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE_BASEDIR='"$(BASE_DIR)"'
endif
ifeq ($(BR2_PIC_PIE),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR2_PIC_PIE
endif
ifeq ($(BR2_RELRO_PARTIAL),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR2_RELRO_PARTIAL
else ifeq ($(BR2_RELRO_FULL),y)
TOOLCHAIN_WRAPPER_ARGS += -DBR2_RELRO_FULL
endif
define TOOLCHAIN_WRAPPER_BUILD
$(HOSTCC) $(HOST_CFLAGS) $(TOOLCHAIN_WRAPPER_ARGS) \
-s -Wl,--hash-style=$(TOOLCHAIN_WRAPPER_HASH_STYLE) \
toolchain/toolchain-wrapper.c \
-o $(@D)/toolchain-wrapper
endef
define TOOLCHAIN_WRAPPER_INSTALL
$(INSTALL) -D -m 0755 $(@D)/toolchain-wrapper \
$(HOST_DIR)/bin/toolchain-wrapper
endef