Cache compiler metadata and reuse it at installworld time.

Right after cross-tools, a compiler-metadata.mk file is created that
stores all of the bsd.compiler.mk metadata.  It is then read in
with a fail-safe during installworld time.

The file is explicitly removed when invoking cross-tools to ensure that
a stale file is not left around from odd manual 'make _cross-tools' ->
'make installworld' invocations.

This fixes several issues:
    - With WITH_SYSTEM_COMPILER (default yes on head and no on releng/11.0):
      If you build on a system where the bootstrap compiler does not
      build due to the host compiler matching the in-tree one, but then
      installworld on another system where that logic fails (a
      bootstrap compiler is needed), the installworld immediately fails
      with:
           sh: cc: not found
      Note that fixing this logic may then hit a case where a rebuild is
      attempted in installworld.  Normally cc would be ran with
      'CFLAGS+=ERROR-tried-to-rebuild-during-make-install' to cause an
      error such as:
          cc: error: no such file or directory: 'ERROR-tried-to-rebuild-during-make-install'
      However, now it will just fail with the 'cc: not found' error.
      Inspection of the compile line will show
      'ERROR-tried-to-rebuild-during-make-install';  It's not useful to
      set CC to anything other than 'cc' during install as it is more
      helpful to see the attempted compile rather than some other bogus
      error.
    - This now avoids running bsd.compiler.mk (cc executions) even more
      during installworld.  There are compiler-dependent SUBDIR in the
      tree which required having a compiler during install.

There is at least 1 case where CC is still executed in the install,
such as from a LOOKUP!= in secure/lib/libcrypto/Makefile.inc checking
for 'vzeroall' support.  This is not significant for installworld
as the lookup has a fallback (and hides its error) and only modifies CFLAGS,
thus it's not worth fixing.

PR:		212877
MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon

1 files changed, 35 insertions, 6 deletions

diff --git a/Makefile.inc1 b/Makefile.inc1
index 55e391d3fe64..1a72d2b007a4 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -78,6 +78,19 @@ MK_CLANG_BOOTSTRAP=	no
 MK_GCC_BOOTSTRAP=	no
 .endif
 
+MAKEOBJDIRPREFIX?=	/usr/obj
+.if ${MACHINE} == ${TARGET} && ${MACHINE_ARCH} == ${TARGET_ARCH} && !defined(CROSS_BUILD_TESTING)
+OBJTREE=	${MAKEOBJDIRPREFIX}
+.else
+OBJTREE=	${MAKEOBJDIRPREFIX}/${TARGET}.${TARGET_ARCH}
+.endif
+
+# Pull in compiler metadata from buildworld/toolchain if possible to avoid
+# running CC from bsd.compiler.mk.
+.if make(installworld) || make(install)
+.-include "${OBJTREE}${.CURDIR}/compiler-metadata.mk"
+.endif
+
 # Pull in COMPILER_TYPE and COMPILER_FREEBSD_VERSION early.
 .include <bsd.compiler.mk>
 .include "share/mk/src.opts.mk"
@@ -163,6 +176,20 @@ CROSSENV+=	COMPILER_VERSION=${X_COMPILER_VERSION} \
 		COMPILER_FREEBSD_VERSION=${X_COMPILER_FREEBSD_VERSION}
 .endif
 .endif
+# Store some compiler metadata for use in installworld where we don't
+# want to invoke CC at all.
+_COMPILER_METADATA_VARS=	COMPILER_VERSION \
+				COMPILER_TYPE \
+				COMPILER_FEATURES \
+				COMPILER_FREEBSD_VERSION
+compiler-metadata.mk: .PHONY .META
+	@: > ${.TARGET}
+	@echo ".info Using cached compiler metadata from build at $$(hostname) on $$(date)" \
+	    > ${.TARGET}
+.for v in ${_COMPILER_METADATA_VARS}
+	@echo "${v}=${${v}}" >> ${.TARGET}
+.endfor
+	@echo ".export ${_COMPILER_METADATA_VARS}" >> ${.TARGET}
 
 # Handle external binutils.
 .if defined(CROSS_TOOLCHAIN_PREFIX)
@@ -304,7 +331,6 @@ SVN=   ${_P}/${_S}
 .endif
 SVNFLAGS?=	-r HEAD
 
-MAKEOBJDIRPREFIX?=	/usr/obj
 .if !defined(OSRELDATE)
 .if exists(/usr/include/osreldate.h)
 OSRELDATE!=	awk '/^\#define[[:space:]]*__FreeBSD_version/ { print $$3 }' \
@@ -401,11 +427,6 @@ BUILD_ARCH!=	uname -p
 .error To cross-build, set TARGET_ARCH.
 .endif
 .endif
-.if ${MACHINE} == ${TARGET} && ${MACHINE_ARCH} == ${TARGET_ARCH} && !defined(CROSS_BUILD_TESTING)
-OBJTREE=	${MAKEOBJDIRPREFIX}
-.else
-OBJTREE=	${MAKEOBJDIRPREFIX}/${TARGET}.${TARGET_ARCH}
-.endif
 WORLDTMP=	${OBJTREE}${.CURDIR}/tmp
 BPATH=		${WORLDTMP}/legacy/usr/sbin:${WORLDTMP}/legacy/usr/bin:${WORLDTMP}/legacy/bin
 XPATH=		${WORLDTMP}/usr/sbin:${WORLDTMP}/usr/bin
@@ -766,8 +787,15 @@ _cross-tools:
 	@echo "--------------------------------------------------------------"
 	@echo ">>> stage 3: cross tools"
 	@echo "--------------------------------------------------------------"
+	@rm -f ${.OBJDIR}/compiler-metadata.mk
 	${_+_}cd ${.CURDIR}; ${XMAKE} cross-tools
 	${_+_}cd ${.CURDIR}; ${XMAKE} kernel-tools
+_compiler-metadata:
+	@echo
+	@echo "--------------------------------------------------------------"
+	@echo ">>> stage 3.1: recording compiler metadata"
+	@echo "--------------------------------------------------------------"
+	${_+_}cd ${.CURDIR}; ${WMAKE} compiler-metadata.mk
 _includes:
 	@echo
 	@echo "--------------------------------------------------------------"
@@ -801,6 +829,7 @@ WMAKE_TGTS+=	_worldtmp _legacy
 WMAKE_TGTS+=	_bootstrap-tools
 .endif
 WMAKE_TGTS+=	_cleanobj _obj _build-tools _cross-tools
+WMAKE_TGTS+=	_compiler-metadata
 WMAKE_TGTS+=	_includes _libraries
 WMAKE_TGTS+=	everything
 .if defined(LIBCOMPAT) && empty(SUBDIR_OVERRIDE)