From 7b00d4a90af1d7bff50833ffe1216cf59592353a Mon Sep 17 00:00:00 2001
From: Andre Heider <a.heider@gmail.com>
Date: Wed, 18 Jan 2023 22:42:28 +0100
Subject: [PATCH] Add BPF_LDFLAGS to allow overwriting llc's -march argument

The argument to clang's -target isn't necessarily the same as to
llc's -march.

Analogue to BPF_CFLAGS, introduce BPF_LDFLAGS to allow e.g.:
BPF_TARGET="mipsel-linux-gnu" BPF_LDFLAGS="-march=bpfel -mcpu=v3"

Signed-off-by: Andre Heider <a.heider@gmail.com>
---
 configure           | 2 ++
 lib/common.mk       | 2 +-
 lib/libxdp/Makefile | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

--- a/configure
+++ b/configure
@@ -17,10 +17,12 @@ check_opts()
     : ${DYNAMIC_LIBXDP:=0}
     : ${MAX_DISPATCHER_ACTIONS:=10}
     : ${BPF_TARGET:=bpf}
+    : ${BPF_LDFLAGS:=-march=$(BPF_TARGET)}
     echo "PRODUCTION:=${PRODUCTION}" >>$CONFIG
     echo "DYNAMIC_LIBXDP:=${DYNAMIC_LIBXDP}" >>$CONFIG
     echo "MAX_DISPATCHER_ACTIONS:=${MAX_DISPATCHER_ACTIONS}" >>$CONFIG
     echo "BPF_TARGET:=${BPF_TARGET}" >>$CONFIG
+    echo "BPF_LDFLAGS:=${BPF_LDFLAGS}" >>$CONFIG
 }
 
 find_tool()
--- a/lib/common.mk
+++ b/lib/common.mk
@@ -118,7 +118,7 @@ $(XDP_OBJ): %.o: %.c $(KERN_USER_H) $(EX
 	    -Werror \
 	    $(BPF_CFLAGS) \
 	    -O2 -emit-llvm -c -g -o ${@:.o=.ll} $<
-	$(QUIET_LLC)$(LLC) -march=$(BPF_TARGET) -filetype=obj -o $@ ${@:.o=.ll}
+	$(QUIET_LLC)$(LLC) $(BPF_LDFLAGS) -filetype=obj -o $@ ${@:.o=.ll}
 
 $(BPF_SKEL_H): %.skel.h: %.bpf.o
 	$(QUIET_GEN)$(BPFTOOL) gen skeleton $< name ${@:.skel.h=} > $@
--- a/lib/libxdp/Makefile
+++ b/lib/libxdp/Makefile
@@ -145,7 +145,7 @@ $(XDP_OBJS): %.o: %.c $(BPF_HEADERS) $(L
 	    -Werror \
 	    $(BPF_CFLAGS) \
 	    -O2 -emit-llvm -c -g -o ${@:.o=.ll} $<
-	$(QUIET_LLC)$(LLC) -march=$(BPF_TARGET) -filetype=obj -o $@ ${@:.o=.ll}
+	$(QUIET_LLC)$(LLC) $(BPF_LDFLAGS) -filetype=obj -o $@ ${@:.o=.ll}
 
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