From 65f28f63a73d3371d9d724a2018be6d1ada0d3e0 Mon Sep 17 00:00:00 2001
From: Jessica Clarke <jrtc27@FreeBSD.org>
Date: Thu, 27 Jul 2023 05:10:47 +0100
Subject: [PATCH] tools/build: Create toolchain symlinks for non-absolute
 compiler/linker

If any of the toolchain variables are not absolute then we need to
create a symlink in WORLDTMP/legacy/bin in order to make them available
during a BUILD_WITH_STRICT_TMPPATH build.

Reviewed by:	brooks, jhb
Differential Revision:	https://reviews.freebsd.org/D41188
---
 Makefile.inc1        |  5 ++---
 tools/build/Makefile | 27 ++++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Makefile.inc1 b/Makefile.inc1
index 3f0546861bbd..964bdfc08699 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -602,9 +602,8 @@ STRICTTMPPATH=	${XPATH}:${BPATH}:${UNIVERSE_TOOLCHAIN_PATH}
 # still allow using the old behaviour (inheriting $PATH) if
 # BUILD_WITH_STRICT_TMPPATH is set to 0 but this will eventually be removed.
 
-# Currently strict $PATH can cause build failures and does not work yet with
-# USING_SYSTEM_LINKER/USING_SYSTEM_COMPILER. Once these issues have been
-# resolved it will be turned on by default.
+# Currently strict $PATH can cause build failures. Once the remaining issues
+# have been resolved it will be turned on by default.
 BUILD_WITH_STRICT_TMPPATH?=0
 .if defined(CROSSBUILD_HOST)
 # When building on non-FreeBSD we can't rely on the tools in /usr/bin being compatible
diff --git a/tools/build/Makefile b/tools/build/Makefile
index 7d6ed8befb30..46fd5c7d3159 100644
--- a/tools/build/Makefile
+++ b/tools/build/Makefile
@@ -312,6 +312,8 @@ _host_tools_to_symlink=	basename bzip2 bunzip2 chmod chown cmp comm cp date dd \
 _make_abs!=	which "${MAKE}"
 _host_abs_tools_to_symlink=	${_make_abs}:make ${_make_abs}:bmake
 
+_LINK_HOST_TOOL=	ln -sfn
+
 .if ${.MAKE.OS} == "FreeBSD"
 # When building on FreeBSD we always copy the host tools instead of linking
 # into WORLDTMP to avoid issues with incompatible libraries (see r364030).
@@ -322,7 +324,7 @@ _COPY_HOST_TOOL=	cp -pf
 # tools to another directory with cp -p results in freezes on macOS Big Sur for
 # some unknown reason. It can also break building inside docker containers if
 # there are ACLs on shared volumes.
-_COPY_HOST_TOOL=	ln -sfn
+_COPY_HOST_TOOL=	${_LINK_HOST_TOOL}
 
 .if ${.MAKE.OS} == "Darwin"
 # /usr/bin/cpp may invoke xcrun:
@@ -335,6 +337,20 @@ _host_abs_tools_to_symlink+=	/bin/bash:sh
 _host_tools_to_symlink:=	${_host_tools_to_symlink:Nsh}
 .endif
 
+# We also need to symlink any non-absolute toolchain commands. Clang finds its
+# resource directory relative to itself, so CC/CXX/CPP must be symlinked, and
+# we do the same for LD for consistency. There should be no concerns about
+# installing over the current system since we don't use the toolchain during
+# install.
+.for var in CC CXX CPP LD
+.for X in $${_empty_var_} X
+.if !empty(${X}${var}) && !${${X}${var}:M/*} && \
+	!${_toolchain_tools_to_symlink:U:M${${X}${var}}}
+_toolchain_tools_to_symlink+=	${${X}${var}}
+.endif
+.endfor
+.endfor
+
 host-symlinks:
 	@echo "Linking host tools into ${DESTDIR}/bin"
 .for _tool in ${_host_tools_to_symlink}
@@ -359,6 +375,15 @@ host-symlinks:
 	rm -f ${DESTDIR}/usr/libexec/flua
 	${_COPY_HOST_TOOL} /usr/libexec/flua ${DESTDIR}/usr/libexec/flua
 .endif
+.for _tool in ${_toolchain_tools_to_symlink}
+	@export PATH=$${PATH}:/usr/local/bin; \
+	source_path=`which ${_tool} || echo /dev/null/no/such`; \
+	if [ ! -e "$${source_path}" ] ; then \
+		echo "Cannot find host tool '${_tool}' in PATH ($$PATH)." >&2; false; \
+	fi; \
+	rm -f "${DESTDIR}/bin/${_tool}"; \
+	${_LINK_HOST_TOOL} "$${source_path}" "${DESTDIR}/bin/${_tool}"
+.endfor
 
 # Create all the directories that are needed during the legacy, bootstrap-tools
 # and cross-tools stages. We do this here using mkdir since mtree may not exist