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-rw-r--r--samples/bpf/Makefile11
1 files changed, 10 insertions, 1 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 4f1ed0e3cf9f..e29b1e89dd3e 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -211,6 +211,8 @@ TPROGLDLIBS_xsk_fwd += -pthread
# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
LLC ?= llc
CLANG ?= clang
+OPT ?= opt
+LLVM_DIS ?= llvm-dis
LLVM_OBJCOPY ?= llvm-objcopy
BTF_PAHOLE ?= pahole
@@ -303,6 +305,11 @@ $(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
# asm/sysreg.h - inline assembly used by it is incompatible with llvm.
# But, there is no easy way to fix it, so just exclude it since it is
# useless for BPF samples.
+# below we use long chain of commands, clang | opt | llvm-dis | llc,
+# to generate final object file. 'clang' compiles the source into IR
+# with native target, e.g., x64, arm64, etc. 'opt' does bpf CORE IR builtin
+# processing (llvm12) and IR optimizations. 'llvm-dis' converts
+# 'opt' output to IR, and finally 'llc' generates bpf byte code.
$(obj)/%.o: $(src)/%.c
@echo " CLANG-bpf " $@
$(Q)$(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(BPF_EXTRA_CFLAGS) \
@@ -314,7 +321,9 @@ $(obj)/%.o: $(src)/%.c
-Wno-address-of-packed-member -Wno-tautological-compare \
-Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \
-I$(srctree)/samples/bpf/ -include asm_goto_workaround.h \
- -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@
+ -O2 -emit-llvm -Xclang -disable-llvm-passes -c $< -o - | \
+ $(OPT) -O2 -mtriple=bpf-pc-linux | $(LLVM_DIS) | \
+ $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@
ifeq ($(DWARF2BTF),y)
$(BTF_PAHOLE) -J $@
endif