[bpf-next,10/11] libbpf: makefile: add C/CXX/LDFLAGS to libbpf.so and test_libpf targets
diff mbox series

Message ID 20190910103830.20794-11-ivan.khoronzhuk@linaro.org
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series
  • samples: bpf: improve/fix cross-compilation
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Commit Message

Ivan Khoronzhuk Sept. 10, 2019, 10:38 a.m. UTC
In case of LDFLAGS and EXTRA_CC/CXX flags there is no way to pass them
correctly to build command, for instance when --sysroot is used or
external libraries are used, like -lelf, wich can be absent in
toolchain. This is used for samples/bpf cross-compiling allowing to
get elf lib from sysroot.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 samples/bpf/Makefile   |  8 +++++++-
 tools/lib/bpf/Makefile | 11 ++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

Comments

Yonghong Song Sept. 13, 2019, 9:43 p.m. UTC | #1
On 9/10/19 11:38 AM, Ivan Khoronzhuk wrote:
> In case of LDFLAGS and EXTRA_CC/CXX flags there is no way to pass them
> correctly to build command, for instance when --sysroot is used or
> external libraries are used, like -lelf, wich can be absent in
> toolchain. This is used for samples/bpf cross-compiling allowing to
> get elf lib from sysroot.
> 
> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
> ---
>   samples/bpf/Makefile   |  8 +++++++-
>   tools/lib/bpf/Makefile | 11 ++++++++---
>   2 files changed, 15 insertions(+), 4 deletions(-)

Could you separate this patch into two?
One of libbpf and another for samples.

The subject 'libbpf: ...' is not entirely accurate.

> 
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 79c9aa41832e..4edc5232cfc1 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -186,6 +186,10 @@ ccflags-y += -I$(srctree)/tools/perf
>   ccflags-y += $(D_OPTIONS)
>   ccflags-y += -Wall
>   ccflags-y += -fomit-frame-pointer
> +
> +EXTRA_CXXFLAGS := $(ccflags-y)
> +
> +# options not valid for C++
>   ccflags-y += -Wmissing-prototypes
>   ccflags-y += -Wstrict-prototypes
>   
> @@ -252,7 +256,9 @@ clean:
>   
>   $(LIBBPF): FORCE
>   # Fix up variables inherited from Kbuild that tools/ build system won't like
> -	$(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O=
> +	$(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(PROGS_CFLAGS)" \
> +		EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(PROGS_LDFLAGS) \
> +		srctree=$(BPF_SAMPLES_PATH)/../../ O=
>   
>   $(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
>   	$(call filechk,offsets,__SYSCALL_NRS_H__)
> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
> index c6f94cffe06e..bccfa556ef4e 100644
> --- a/tools/lib/bpf/Makefile
> +++ b/tools/lib/bpf/Makefile
> @@ -94,6 +94,10 @@ else
>     CFLAGS := -g -Wall
>   endif
>   
> +ifdef EXTRA_CXXFLAGS
> +  CXXFLAGS := $(EXTRA_CXXFLAGS)
> +endif
> +
>   ifeq ($(feature-libelf-mmap), 1)
>     override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
>   endif
> @@ -176,8 +180,9 @@ $(BPF_IN): force elfdep bpfdep
>   $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
>   
>   $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN)
> -	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
> -				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
> +	$(QUIET_LINK)$(CC) $(LDFLAGS) \
> +		--shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
> +		-Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
>   	@ln -sf $(@F) $(OUTPUT)libbpf.so
>   	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
>   
> @@ -185,7 +190,7 @@ $(OUTPUT)libbpf.a: $(BPF_IN)
>   	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
>   
>   $(OUTPUT)test_libbpf: test_libbpf.cpp $(OUTPUT)libbpf.a
> -	$(QUIET_LINK)$(CXX) $(INCLUDES) $^ -lelf -o $@
> +	$(QUIET_LINK)$(CXX) $(CXXFLAGS) $(LDFLAGS) $(INCLUDES) $^ -lelf -o $@
>   
>   $(OUTPUT)libbpf.pc:
>   	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
>
Ivan Khoronzhuk Sept. 13, 2019, 10:33 p.m. UTC | #2
On Fri, Sep 13, 2019 at 09:43:22PM +0000, Yonghong Song wrote:
>
>
>On 9/10/19 11:38 AM, Ivan Khoronzhuk wrote:
>> In case of LDFLAGS and EXTRA_CC/CXX flags there is no way to pass them
>> correctly to build command, for instance when --sysroot is used or
>> external libraries are used, like -lelf, wich can be absent in
>> toolchain. This is used for samples/bpf cross-compiling allowing to
>> get elf lib from sysroot.
>>
>> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
>> ---
>>   samples/bpf/Makefile   |  8 +++++++-
>>   tools/lib/bpf/Makefile | 11 ++++++++---
>>   2 files changed, 15 insertions(+), 4 deletions(-)
>
>Could you separate this patch into two?
>One of libbpf and another for samples.
>
>The subject 'libbpf: ...' is not entirely accurate.
Yes, ofc.
But there is too many patches already, but better a lot of small
changes then couple huge.

>
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 79c9aa41832e..4edc5232cfc1 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -186,6 +186,10 @@ ccflags-y += -I$(srctree)/tools/perf
>>   ccflags-y += $(D_OPTIONS)
>>   ccflags-y += -Wall
>>   ccflags-y += -fomit-frame-pointer
>> +
>> +EXTRA_CXXFLAGS := $(ccflags-y)
>> +
>> +# options not valid for C++
>>   ccflags-y += -Wmissing-prototypes
>>   ccflags-y += -Wstrict-prototypes
>>
>> @@ -252,7 +256,9 @@ clean:
>>
>>   $(LIBBPF): FORCE
>>   # Fix up variables inherited from Kbuild that tools/ build system won't like
>> -	$(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O=
>> +	$(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(PROGS_CFLAGS)" \
>> +		EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(PROGS_LDFLAGS) \
>> +		srctree=$(BPF_SAMPLES_PATH)/../../ O=
>>
>>   $(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
>>   	$(call filechk,offsets,__SYSCALL_NRS_H__)
>> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
>> index c6f94cffe06e..bccfa556ef4e 100644
>> --- a/tools/lib/bpf/Makefile
>> +++ b/tools/lib/bpf/Makefile
>> @@ -94,6 +94,10 @@ else
>>     CFLAGS := -g -Wall
>>   endif
>>
>> +ifdef EXTRA_CXXFLAGS
>> +  CXXFLAGS := $(EXTRA_CXXFLAGS)
>> +endif
>> +
>>   ifeq ($(feature-libelf-mmap), 1)
>>     override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
>>   endif
>> @@ -176,8 +180,9 @@ $(BPF_IN): force elfdep bpfdep
>>   $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
>>
>>   $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN)
>> -	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
>> -				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
>> +	$(QUIET_LINK)$(CC) $(LDFLAGS) \
>> +		--shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
>> +		-Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
>>   	@ln -sf $(@F) $(OUTPUT)libbpf.so
>>   	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
>>
>> @@ -185,7 +190,7 @@ $(OUTPUT)libbpf.a: $(BPF_IN)
>>   	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
>>
>>   $(OUTPUT)test_libbpf: test_libbpf.cpp $(OUTPUT)libbpf.a
>> -	$(QUIET_LINK)$(CXX) $(INCLUDES) $^ -lelf -o $@
>> +	$(QUIET_LINK)$(CXX) $(CXXFLAGS) $(LDFLAGS) $(INCLUDES) $^ -lelf -o $@
>>
>>   $(OUTPUT)libbpf.pc:
>>   	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
>>

Patch
diff mbox series

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 79c9aa41832e..4edc5232cfc1 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -186,6 +186,10 @@  ccflags-y += -I$(srctree)/tools/perf
 ccflags-y += $(D_OPTIONS)
 ccflags-y += -Wall
 ccflags-y += -fomit-frame-pointer
+
+EXTRA_CXXFLAGS := $(ccflags-y)
+
+# options not valid for C++
 ccflags-y += -Wmissing-prototypes
 ccflags-y += -Wstrict-prototypes
 
@@ -252,7 +256,9 @@  clean:
 
 $(LIBBPF): FORCE
 # Fix up variables inherited from Kbuild that tools/ build system won't like
-	$(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O=
+	$(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(PROGS_CFLAGS)" \
+		EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(PROGS_LDFLAGS) \
+		srctree=$(BPF_SAMPLES_PATH)/../../ O=
 
 $(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
 	$(call filechk,offsets,__SYSCALL_NRS_H__)
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index c6f94cffe06e..bccfa556ef4e 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -94,6 +94,10 @@  else
   CFLAGS := -g -Wall
 endif
 
+ifdef EXTRA_CXXFLAGS
+  CXXFLAGS := $(EXTRA_CXXFLAGS)
+endif
+
 ifeq ($(feature-libelf-mmap), 1)
   override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
 endif
@@ -176,8 +180,9 @@  $(BPF_IN): force elfdep bpfdep
 $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
 
 $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN)
-	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
-				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
+	$(QUIET_LINK)$(CC) $(LDFLAGS) \
+		--shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
+		-Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
 	@ln -sf $(@F) $(OUTPUT)libbpf.so
 	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
 
@@ -185,7 +190,7 @@  $(OUTPUT)libbpf.a: $(BPF_IN)
 	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
 
 $(OUTPUT)test_libbpf: test_libbpf.cpp $(OUTPUT)libbpf.a
-	$(QUIET_LINK)$(CXX) $(INCLUDES) $^ -lelf -o $@
+	$(QUIET_LINK)$(CXX) $(CXXFLAGS) $(LDFLAGS) $(INCLUDES) $^ -lelf -o $@
 
 $(OUTPUT)libbpf.pc:
 	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \