From e5c6dece9888a4eb519220938ea98c50d24a9f51 Mon Sep 17 00:00:00 2001
From: Ed Maste <emaste@FreeBSD.org>
Date: Thu, 15 Aug 2019 12:48:17 +0000
Subject: [PATCH] do not enable userland retpoline if not supported by
 compiler/linker

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21101
---
 share/mk/bsd.lib.mk  | 6 ++++++
 share/mk/bsd.prog.mk | 5 +++++
 2 files changed, 11 insertions(+)

diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
index 244d68762155..22655768cc66 100644
--- a/share/mk/bsd.lib.mk
+++ b/share/mk/bsd.lib.mk
@@ -3,6 +3,8 @@
 #
 
 .include <bsd.init.mk>
+.include <bsd.compiler.mk>
+.include <bsd.linker.mk>
 
 .if defined(LIB_CXX) || defined(SHLIB_CXX)
 _LD=	${CXX}
@@ -74,9 +76,13 @@ TAG_ARGS=	-T ${TAGS:[*]:S/ /,/g}
 LDFLAGS+= -Wl,-znow
 .endif
 .if ${MK_RETPOLINE} != "no"
+.if ${COMPILER_FEATURES:Mretpoline} && ${LINKER_FEATURES:Mretpoline}
 CFLAGS+= -mretpoline
 CXXFLAGS+= -mretpoline
 LDFLAGS+= -Wl,-zretpolineplt
+.else
+.warning Retpoline requested but not supported by compiler or linker
+.endif
 .endif
 
 .if ${MK_DEBUG_FILES} != "no" && empty(DEBUG_FLAGS:M-g) && \
diff --git a/share/mk/bsd.prog.mk b/share/mk/bsd.prog.mk
index 0ce546278445..46eb6bda4caf 100644
--- a/share/mk/bsd.prog.mk
+++ b/share/mk/bsd.prog.mk
@@ -3,6 +3,7 @@
 
 .include <bsd.init.mk>
 .include <bsd.compiler.mk>
+.include <bsd.linker.mk>
 
 .SUFFIXES: .out .o .bc .c .cc .cpp .cxx .C .m .y .l .ll .ln .s .S .asm
 
@@ -44,12 +45,16 @@ CXXFLAGS+= -fPIE
 LDFLAGS+= -pie
 .endif
 .if ${MK_RETPOLINE} != "no"
+.if ${COMPILER_FEATURES:Mretpoline} && ${LINKER_FEATURES:Mretpoline}
 CFLAGS+= -mretpoline
 CXXFLAGS+= -mretpoline
 # retpolineplt is broken with static linking (PR 233336)
 .if !defined(NO_SHARED) || ${NO_SHARED:tl} == "no"
 LDFLAGS+= -Wl,-zretpolineplt
 .endif
+.else
+.warning Retpoline requested but not supported by compiler or linker
+.endif
 .endif
 
 .if defined(CRUNCH_CFLAGS)