From cfd267a56a2bfc34afc49f4b3be86965a5b56112 Mon Sep 17 00:00:00 2001
From: Ariel Otilibili <otilibil@eurecom.fr>
Date: Mon, 9 Sep 2024 17:47:44 +0200
Subject: [PATCH] ebpf_prog/Makefile: temp files are now handled by a pattern
 rule

* `%.bc` are autoremoved: these LLVM IR files are intermediate [1]
* `%.o` are now produced by a wildcard search
* introduced `.SUFFIXES:` for cleaning up the implicit rules [2]
* else Makefile would have generated `%.o` from its own database.

[1] https://www.gnu.org/software/make/manual/html_node/Chained-Rules.html
[2] https://www.gnu.org/software/make/manual/html_node/Suffix-Rules.html

Signed-off-by: Ariel Otilibili <otilibil@eurecom.fr>
---
 ebpf_prog/Makefile | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/ebpf_prog/Makefile b/ebpf_prog/Makefile
index 25239506ab..180db955df 100644
--- a/ebpf_prog/Makefile
+++ b/ebpf_prog/Makefile
@@ -5,7 +5,7 @@
 #
 KERNEL_DIR ?= /lib/modules/$(shell uname -r)/source
 KERNEL_HEADERS ?= /usr/src/linux-headers-$(shell uname -r)/
-CLANG ?= clang
+CC = clang
 LLC ?= llc
 LLVM_STRIP ?= llvm-strip -g
 ARCH ?= $(shell uname -m)
@@ -27,8 +27,9 @@ ifeq ($(ARCH),arm)
 	EXTRA_FLAGS = "-D__LINUX_ARM_ARCH__=7"
 endif
 
-BIN := opensnitch.o opensnitch-procs.o opensnitch-dns.o
-CLANG_FLAGS = -I. \
+SRC := $(wildcard *.c)
+BIN := $(SRC:.c=.o)
+CFLAGS = -I. \
 	-I$(KERNEL_HEADERS)/arch/$(ARCH)/include/generated/ \
 	-I$(KERNEL_HEADERS)/include \
 	-include $(KERNEL_DIR)/include/linux/kconfig.h \
@@ -54,10 +55,13 @@ CLANG_FLAGS = -I. \
 
 all: $(BIN)
 
-%.o: %.c
-	$(CLANG) $(CLANG_FLAGS) -c $< -o $@.partial
-	$(LLC) -march=bpf -mcpu=generic -filetype=obj -o $@ $@.partial
-	rm -f $@.partial
+%.bc: %.c
+	$(CC) $(CFLAGS) -c $<
+
+%.o: %.bc
+	$(LLC) -march=bpf -mcpu=generic -filetype=obj -o $@ $<
 
 clean:
-	rm -f *.o *.partial
+	rm -f $(BIN)
+
+.SUFFIXES: