Index: head/share/mk/bsd.compiler.mk
===================================================================
--- head/share/mk/bsd.compiler.mk	(revision 364808)
+++ head/share/mk/bsd.compiler.mk	(revision 364809)
@@ -1,241 +1,244 @@
 # $FreeBSD$
 
 # Setup variables for the compiler
 #
 # COMPILER_TYPE is the major type of compiler. Currently gcc and clang support
 # automatic detection. Other compiler types can be shoe-horned in, but require
 # explicit setting of the compiler type. The compiler type can also be set
 # explicitly if, say, you install gcc as clang...
 #
 # COMPILER_VERSION is a numeric constant equal to:
 #     major * 10000 + minor * 100 + tiny
 # It too can be overridden on the command line. When testing it, be sure to
 # make sure that you are limiting the test to a specific compiler. Testing
 # against 30300 for gcc likely isn't  what you wanted (since versions of gcc
 # prior to 4.2 likely have no prayer of working).
 #
 # COMPILER_FREEBSD_VERSION is the compiler's __FreeBSD_cc_version value.
 #
 # COMPILER_FEATURES will contain one or more of the following, based on
 # compiler support for that feature:
 #
 # - c++17:     supports full (or nearly full) C++17 programming environment.
 # - c++14:     supports full (or nearly full) C++14 programming environment.
 # - c++11:     supports full (or nearly full) C++11 programming environment.
 # - retpoline: supports the retpoline speculative execution vulnerability
 #              mitigation.
 #
 # These variables with an X_ prefix will also be provided if XCC is set.
 #
 # This file may be included multiple times, but only has effect the first time.
 #
 
 .if !target(__<bsd.compiler.mk>__)
 __<bsd.compiler.mk>__:
 
 .include <bsd.opts.mk>
 
 .if defined(_NO_INCLUDE_COMPILERMK)
 # If _NO_INCLUDE_COMPILERMK is set we are doing a make obj/cleandir/cleanobj
 # and might not have a valid compiler in $PATH yet. In this case just set the
 # variables that are expected by the other .mk files and return
 COMPILER_TYPE=none
 X_COMPILER_TYPE=none
 COMPILER_VERSION=0
 X_COMPILER_VERSION=0
 COMPILER_FEATURES=none
 .else
 # command = /usr/local/bin/ccache cc ...
 # wrapper = /usr/local/libexec/ccache/cc ...
 CCACHE_BUILD_TYPE?=	command
 # Handle ccache after CC is determined, but not if CC/CXX are already
 # overridden with a manual setup.
 .if ${MK_CCACHE_BUILD:Uno} == "yes" && \
     !make(test-system-*) && !make(print-dir) && !make(showconfig) && \
     (${CC:M*ccache/world/*} == "" || ${CXX:M*ccache/world/*} == "")
 # CC is always prepended with the ccache wrapper rather than modifying
 # PATH since it is more clear that ccache is used and avoids wasting time
 # for mkdep/linking/asm builds.
 LOCALBASE?=		/usr/local
 CCACHE_WRAPPER_PATH?=	${LOCALBASE}/libexec/ccache
 CCACHE_BIN?=		${LOCALBASE}/bin/ccache
 .if exists(${CCACHE_BIN})
 # Export to ensure sub-makes can filter it out for mkdep/linking and
 # to chain down into kernel build which won't include this file.
 .export CCACHE_BIN
 # Expand and export some variables so they may be based on make vars.
 # This allows doing something like the following in the environment:
 # CCACHE_BASEDIR='${SRCTOP:H}' MAKEOBJDIRPREFIX='${SRCTOP:H}/obj'
 .for var in CCACHE_LOGFILE CCACHE_BASEDIR
 .if defined(${var})
 ${var}:=	${${var}}
 .export		${var}
 .endif
 .endfor
 # Handle bootstrapped compiler changes properly by hashing their content
 # rather than checking mtime.  For external compilers it should be safe
 # to use the more optimal mtime check.
 # XXX: CCACHE_COMPILERCHECK= string:<compiler_version, compiler_build_rev, compiler_patch_rev, compiler_default_target, compiler_default_sysroot>
 .if ${CC:N${CCACHE_BIN}:[1]:M/*} == ""
 CCACHE_COMPILERCHECK?=	content
 .else
 CCACHE_COMPILERCHECK?=	mtime
 .endif
 .export CCACHE_COMPILERCHECK
 # Ensure no bogus CCACHE_PATH leaks in which might avoid the in-tree compiler.
 .if !empty(CCACHE_PATH)
 CCACHE_PATH=
 .export CCACHE_PATH
 .endif
 .if ${CCACHE_BUILD_TYPE} == "command"
 # Remove ccache from the PATH to prevent double calls and wasted CPP/LD time.
 PATH:=	${PATH:C,:?${CCACHE_WRAPPER_PATH}(/world)?(:$)?,,g}
 # Override various toolchain vars.
 .for var in CC CXX HOST_CC HOST_CXX
 .if defined(${var}) && ${${var}:M${CCACHE_BIN}} == ""
 ${var}:=	${CCACHE_BIN} ${${var}}
 .endif
 .endfor
 .else
 # Need to ensure CCACHE_WRAPPER_PATH is the first in ${PATH}
 PATH:=	${PATH:C,:?${CCACHE_WRAPPER_PATH}(/world)?(:$)?,,g}
 PATH:=	${CCACHE_WRAPPER_PATH}:${PATH}
 CCACHE_WRAPPER_PATH_PFX=	${CCACHE_WRAPPER_PATH}:
 .endif	# ${CCACHE_BUILD_TYPE} == "command"
 # GCC does not need the CCACHE_CPP2 hack enabled by default in devel/ccache.
 # The port enables it due to ccache passing preprocessed C to clang
 # which fails with -Wparentheses-equality, -Wtautological-compare, and
 # -Wself-assign on macro-expanded lines.
 .if defined(COMPILER_TYPE) && ${COMPILER_TYPE} == "gcc"
 CCACHE_NOCPP2=	1
 .export CCACHE_NOCPP2
 .endif
 # Canonicalize CCACHE_DIR for meta mode usage.
 .if !defined(CCACHE_DIR)
 CCACHE_DIR!=	${CCACHE_BIN} -p | awk '$$2 == "cache_dir" {print $$4}'
 .export CCACHE_DIR
 .endif
 .if !empty(CCACHE_DIR) && empty(.MAKE.META.IGNORE_PATHS:M${CCACHE_DIR})
 CCACHE_DIR:=	${CCACHE_DIR:tA}
 .MAKE.META.IGNORE_PATHS+= ${CCACHE_DIR}
 .export CCACHE_DIR
 .endif
 # ccache doesn't affect build output so let it slide for meta mode
 # comparisons.
 .MAKE.META.IGNORE_PATHS+= ${CCACHE_BIN}
 ccache-print-options: .PHONY
 	@${CCACHE_BIN} -p
 .endif	# exists(${CCACHE_BIN})
 .endif	# ${MK_CCACHE_BUILD} == "yes"
 
 _cc_vars=CC $${_empty_var_}
 .if !empty(_WANT_TOOLCHAIN_CROSS_VARS)
 # Only the toplevel makefile needs to compute the X_COMPILER_* variables.
 # Skipping the computation of the unused X_COMPILER_* in the subdirectory
 # makefiles can save a noticeable amount of time when walking the whole source
 # tree (e.g. during make includes, etc.).
 _cc_vars+=XCC X_
 .endif
 
 .for cc X_ in ${_cc_vars}
 .if ${cc} == "CC" || !empty(XCC)
 # Try to import COMPILER_TYPE and COMPILER_VERSION from parent make.
 # The value is only used/exported for the same environment that impacts
 # CC and COMPILER_* settings here.
 _exported_vars=	${X_}COMPILER_TYPE ${X_}COMPILER_VERSION \
 		${X_}COMPILER_FREEBSD_VERSION ${X_}COMPILER_RESOURCE_DIR
 ${X_}_cc_hash=	${${cc}}${MACHINE}${PATH}
 ${X_}_cc_hash:=	${${X_}_cc_hash:hash}
-# Only import if none of the vars are set somehow else.
+# Only import if none of the vars are set differently somehow else.
 _can_export=	yes
 .for var in ${_exported_vars}
-.if defined(${var})
+.if defined(${var}) && (!defined(${var}__${${X_}_cc_hash}) || ${${var}__${${X_}_cc_hash}} != ${${var}})
+.if defined(${var}__${${X_}_ld_hash})
+.info "Cannot import ${X_}COMPILER variables since cached ${var} is different: ${${var}__${${X_}_cc_hash}} != ${${var}}"
+.endif
 _can_export=	no
 .endif
 .endfor
 .if ${_can_export} == yes
 .for var in ${_exported_vars}
 .if defined(${var}__${${X_}_cc_hash})
 ${var}=	${${var}__${${X_}_cc_hash}}
 .endif
 .endfor
 .endif
 
 .if ${cc} == "CC" || (${cc} == "XCC" && ${XCC} != ${CC})
 .if ${MACHINE} == "common"
 # common is a pseudo machine for architecture independent
 # generated files - thus there is no compiler.
 ${X_}COMPILER_TYPE= none
 ${X_}COMPILER_VERSION= 0
 ${X_}COMPILER_FREEBSD_VERSION= 0
 .elif !defined(${X_}COMPILER_TYPE) || !defined(${X_}COMPILER_VERSION)
 _v!=	${${cc}:N${CCACHE_BIN}} --version || echo 0.0.0
 
 .if !defined(${X_}COMPILER_TYPE)
 . if ${${cc}:T:M*gcc*}
 ${X_}COMPILER_TYPE:=	gcc
 . elif ${${cc}:T:M*clang*}
 ${X_}COMPILER_TYPE:=	clang
 . elif ${_v:Mgcc}
 ${X_}COMPILER_TYPE:=	gcc
 . elif ${_v:M\(GCC\)} || ${_v:M*GNU}
 ${X_}COMPILER_TYPE:=	gcc
 . elif ${_v:Mclang} || ${_v:M(clang-*.*.*)}
 ${X_}COMPILER_TYPE:=	clang
 . else
 .error Unable to determine compiler type for ${cc}=${${cc}}.  Consider setting ${X_}COMPILER_TYPE.
 . endif
 .endif
 .if !defined(${X_}COMPILER_VERSION)
 ${X_}COMPILER_VERSION!=echo "${_v:M[1-9]*.[0-9]*}" | awk -F. '{print $$1 * 10000 + $$2 * 100 + $$3;}'
 .endif
 .undef _v
 .endif
 .if !defined(${X_}COMPILER_FREEBSD_VERSION)
 ${X_}COMPILER_FREEBSD_VERSION!=	{ echo "__FreeBSD_cc_version" | ${${cc}:N${CCACHE_BIN}} -E - 2>/dev/null || echo __FreeBSD_cc_version; } | sed -n '$$p'
 # If we get a literal "__FreeBSD_cc_version" back then the compiler
 # is a non-FreeBSD build that doesn't support it or some other error
 # occurred.
 .if ${${X_}COMPILER_FREEBSD_VERSION} == "__FreeBSD_cc_version"
 ${X_}COMPILER_FREEBSD_VERSION=	unknown
 .endif
 .endif
 
 .if !defined(${X_}COMPILER_RESOURCE_DIR)
 ${X_}COMPILER_RESOURCE_DIR!=	${${cc}:N${CCACHE_BIN}} -print-resource-dir 2>/dev/null || echo unknown
 .endif
 
 ${X_}COMPILER_FEATURES=		c++11 c++14
 .if ${${X_}COMPILER_TYPE} == "clang" || \
 	(${${X_}COMPILER_TYPE} == "gcc" && ${${X_}COMPILER_VERSION} >= 70000)
 ${X_}COMPILER_FEATURES+=	c++17
 .endif
 .if ${${X_}COMPILER_TYPE} == "clang"
 ${X_}COMPILER_FEATURES+=	retpoline
 .endif
 
 .else
 # Use CC's values
 X_COMPILER_TYPE=	${COMPILER_TYPE}
 X_COMPILER_VERSION=	${COMPILER_VERSION}
 X_COMPILER_FREEBSD_VERSION=	${COMPILER_FREEBSD_VERSION}
 X_COMPILER_FEATURES=	${COMPILER_FEATURES}
 X_COMPILER_RESOURCE_DIR=	${COMPILER_RESOURCE_DIR}
 .endif	# ${cc} == "CC" || (${cc} == "XCC" && ${XCC} != ${CC})
 
 # 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_}_cc_hash}:=	${${var}}
 .export-env ${var}__${${X_}_cc_hash}
 .undef ${var}__${${X_}_cc_hash}
 .endfor
 
 .endif	# ${cc} == "CC" || !empty(XCC)
 .endfor	# .for cc in CC XCC
 
 .if !defined(_NO_INCLUDE_LINKERMK)
 .include <bsd.linker.mk>
 .endif
 .endif	# defined(_NO_INCLUDE_COMPILERMK)
 .endif	# !target(__<bsd.compiler.mk>__)
Index: head/share/mk/bsd.linker.mk
===================================================================
--- head/share/mk/bsd.linker.mk	(revision 364808)
+++ head/share/mk/bsd.linker.mk	(revision 364809)
@@ -1,132 +1,135 @@
 # $FreeBSD$
 
 # 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.
+# Only import if none of the vars are set differently somehow else.
 _can_export=	yes
 .for var in ${_exported_vars}
-.if defined(${var})
+.if defined(${var}) && (!defined(${var}__${${X_}_ld_hash}) || ${${var}__${${X_}_ld_hash}} != ${${var}})
+.if defined(${var}__${${X_}_ld_hash})
+.info "Cannot import ${X_}LINKER variables since cached ${var} is different: ${${var}__${${X_}_ld_hash}} != ${${var}}"
+.endif
 _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}} -v 2>&1 || 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]}
 .if ${_ld_version:[3]} == "(FreeBSD"
 ${X_}LINKER_FREEBSD_VERSION:=	${_ld_version:[4]:C/.*-([^-]*)\)/\1/}
 .else
 ${X_}LINKER_FREEBSD_VERSION=	0
 .endif
 .elif ${_ld_version:[1]} == "@(\#)PROGRAM:ld"
 # bootstrap linker on MacOS
 ${X_}LINKER_TYPE=        mac
 _v=        ${_ld_version:[2]:S/PROJECT:ld64-//}
 # Convert version 409.12 to 409.12.0 so that the echo + awk below works
 .if empty(_v:M[1-9]*.[0-9]*.[0-9]*) && !empty(_v:M[1-9]*.[0-9]*)
 _v:=${_v}.0
 .else
 # Some versions do not contain a minor version so we need to append .0.0 there
 _v:=${_v}.0.0
 .endif
 .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} == "bfd" && ${${X_}LINKER_VERSION} > 21750
 ${X_}LINKER_FEATURES+=	riscv-relaxations
 .endif
 .if ${${X_}LINKER_TYPE} == "lld" && ${${X_}LINKER_VERSION} >= 60000
 ${X_}LINKER_FEATURES+=	retpoline
 .endif
 .if ${${X_}LINKER_TYPE} == "lld" && ${${X_}LINKER_VERSION} >= 90000
 ${X_}LINKER_FEATURES+=	ifunc-noplt
 .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>__)