freebsd-dev/share/mk/bsd.linker.mk
Ed Maste 7c807d7708 retire LINKER_FEATURES filter flag
And build libdl unconditionally.  All supported FreeBSD linkers accept
-F / --filter so there is no need to test for support.

Discussed with:	kib
Sponsored by:	The FreeBSD Foundation
2018-11-12 20:44:22 +00:00

114 lines
3.4 KiB
Makefile

# $FreeBSD$
# Setup variables for the linker.
#
# LINKER_TYPE is the major type of linker. Currently binutils and lld support
# automatic detection.
#
# LINKER_VERSION is a numeric constant equal to:
# major * 10000 + minor * 100 + tiny
# It too can be overridden on the command line.
#
# LINKER_FEATURES may contain one or more of the following, based on
# linker support for that feature:
#
# - build-id: support for generating a Build-ID note
# - retpoline: support for generating PLT with retpoline speculative
# execution vulnerability mitigation
#
# LINKER_FREEBSD_VERSION is the linker's internal source version.
#
# These variables with an X_ prefix will also be provided if XLD is set.
#
# This file may be included multiple times, but only has effect the first time.
#
.if !target(__<bsd.linker.mk>__)
__<bsd.linker.mk>__:
_ld_vars=LD $${_empty_var_}
.if !empty(_WANT_TOOLCHAIN_CROSS_VARS)
# Only the toplevel makefile needs to compute the X_LINKER_* variables.
_ld_vars+=XLD X_
.endif
.for ld X_ in ${_ld_vars}
.if ${ld} == "LD" || !empty(XLD)
# Try to import LINKER_TYPE and LINKER_VERSION from parent make.
# The value is only used/exported for the same environment that impacts
# LD and LINKER_* settings here.
_exported_vars= ${X_}LINKER_TYPE ${X_}LINKER_VERSION ${X_}LINKER_FEATURES \
${X_}LINKER_FREEBSD_VERSION
${X_}_ld_hash= ${${ld}}${MACHINE}${PATH}
${X_}_ld_hash:= ${${X_}_ld_hash:hash}
# Only import if none of the vars are set somehow else.
_can_export= yes
.for var in ${_exported_vars}
.if defined(${var})
_can_export= no
.endif
.endfor
.if ${_can_export} == yes
.for var in ${_exported_vars}
.if defined(${var}.${${X_}_ld_hash})
${var}= ${${var}.${${X_}_ld_hash}}
.endif
.endfor
.endif
.if ${ld} == "LD" || (${ld} == "XLD" && ${XLD} != ${LD})
.if !defined(${X_}LINKER_TYPE) || !defined(${X_}LINKER_VERSION)
_ld_version!= (${${ld}} --version || echo none) | sed -n 1p
.if ${_ld_version} == "none"
.warning Unable to determine linker type from ${ld}=${${ld}}
.endif
.if ${_ld_version:[1..2]} == "GNU ld"
${X_}LINKER_TYPE= bfd
${X_}LINKER_FREEBSD_VERSION= 0
_v= ${_ld_version:M[1-9].[0-9]*:[1]}
.elif ${_ld_version:[1]} == "LLD"
${X_}LINKER_TYPE= lld
_v= ${_ld_version:[2]}
${X_}LINKER_FREEBSD_VERSION!= \
${${ld}} --version | \
awk '$$3 ~ /FreeBSD/ {print substr($$4, 1, length($$4)-1)}'
.else
.warning Unknown linker from ${ld}=${${ld}}: ${_ld_version}, defaulting to bfd
${X_}LINKER_TYPE= bfd
_v= 2.17.50
.endif
${X_}LINKER_VERSION!= echo "${_v:M[1-9].[0-9]*}" | \
awk -F. '{print $$1 * 10000 + $$2 * 100 + $$3;}'
.undef _ld_version
.undef _v
${X_}LINKER_FEATURES=
.if ${${X_}LINKER_TYPE} != "bfd" || ${${X_}LINKER_VERSION} > 21750
${X_}LINKER_FEATURES+= build-id
${X_}LINKER_FEATURES+= ifunc
.endif
.if ${${X_}LINKER_TYPE} == "lld" && ${${X_}LINKER_VERSION} >= 60000
${X_}LINKER_FEATURES+= retpoline
.endif
.endif
.else
# Use LD's values
X_LINKER_TYPE= ${LINKER_TYPE}
X_LINKER_VERSION= ${LINKER_VERSION}
X_LINKER_FEATURES= ${LINKER_FEATURES}
X_LINKER_FREEBSD_VERSION= ${LINKER_FREEBSD_VERSION}
.endif # ${ld} == "LD" || (${ld} == "XLD" && ${XLD} != ${LD})
# Export the values so sub-makes don't have to look them up again, using the
# hash key computed above.
.for var in ${_exported_vars}
${var}.${${X_}_ld_hash}:= ${${var}}
.export-env ${var}.${${X_}_ld_hash}
.undef ${var}.${${X_}_ld_hash}
.endfor
.endif # ${ld} == "LD" || !empty(XLD)
.endfor # .for ld in LD XLD
.endif # !target(__<bsd.linker.mk>__)