Index: head/sys/conf/kern.post.mk
===================================================================
--- head/sys/conf/kern.post.mk
+++ head/sys/conf/kern.post.mk
@@ -328,6 +328,11 @@
 
 .depend: .PRECIOUS ${SRCS}
 
+.if ${COMPILER_TYPE} == "clang" || \
+    (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60000)
+_MAP_DEBUG_PREFIX= yes
+.endif
+
 _ILINKS= machine
 .if ${MACHINE} != ${MACHINE_CPUARCH} && ${MACHINE} != "arm64"
 _ILINKS+= ${MACHINE_CPUARCH}
@@ -337,11 +342,24 @@
 .endif
 
 # Ensure that the link exists without depending on it when it exists.
+# Ensure that debug info references the path in the source tree.
 .for _link in ${_ILINKS}
 .if !exists(${.OBJDIR}/${_link})
 ${SRCS} ${CLEAN:M*.o}: ${_link}
 .endif
+.if defined(_MAP_DEBUG_PREFIX)
+.if ${_link} == "machine"
+CFLAGS+= -fdebug-prefix-map=./machine=${SYSDIR}/${MACHINE}/include
+.else
+CFLAGS+= -fdebug-prefix-map=./${_link}=${SYSDIR}/${_link}/include
+.endif
+.endif
 .endfor
+
+.if defined(_MAP_DEBUG_PREFIX)
+# Ensure that DWARF info contains a full path for auto-generated headers.
+CFLAGS+= -fdebug-prefix-map=.=${.OBJDIR}
+.endif
 
 ${_ILINKS}:
 	@case ${.TARGET} in \
Index: head/sys/conf/kmod.mk
===================================================================
--- head/sys/conf/kmod.mk
+++ head/sys/conf/kmod.mk
@@ -267,6 +267,11 @@
 	${OBJCOPY} --strip-debug ${.TARGET}
 .endif
 
+.if ${COMPILER_TYPE} == "clang" || \
+    (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60000)
+_MAP_DEBUG_PREFIX= yes
+.endif
+
 _ILINKS=machine
 .if ${MACHINE} != ${MACHINE_CPUARCH} && ${MACHINE} != "arm64"
 _ILINKS+=${MACHINE_CPUARCH}
@@ -283,11 +288,24 @@
 
 # Ensure that the links exist without depending on it when it exists which
 # causes all the modules to be rebuilt when the directory pointed to changes.
+# Ensure that debug info references the path in the source tree.
 .for _link in ${_ILINKS}
 .if !exists(${.OBJDIR}/${_link})
 OBJS_DEPEND_GUESS+=	${_link}
 .endif
+.if defined(_MAP_DEBUG_PREFIX)
+.if ${_link} == "machine"
+CFLAGS+= -fdebug-prefix-map=./machine=${SYSDIR}/${MACHINE}/include
+.else
+CFLAGS+= -fdebug-prefix-map=./${_link}=${SYSDIR}/${_link}/include
+.endif
+.endif
 .endfor
+
+.if defined(_MAP_DEBUG_PREFIX)
+# Ensure that DWARF info contains a full path for auto-generated headers.
+CFLAGS+= -fdebug-prefix-map=.=${.OBJDIR}
+.endif
 
 .NOPATH: ${_ILINKS}