Hi Thomas,
Please find my answers below
Why do you want to use export from the shell environment?
Answer> One scenario that generic scripts or makefiles are used to build DPDK
and Customer components. While building for "make debug" mode; we require DPDK
libraries to be built with compiler specific additives. Hence there are
requirements of having them exported (especially in DPDK shared library mode)
is in practice.
The standard way of overriding a variable with make, is to specify a value on
the make command line.
Answer> Please find my observations while using non modified DPDK versions
CMD:
1) cd $RTE_SDK/$RTE_TARGET
2) make clean; make TOOLCHAIN_CFLAGS="-ggdb -fno-omit-frame-pointer"
Checking for user flags:
# grep -nr "fno-omit-frame-pointer" lib/ | wc -l
66
<these were not expected>
# grep -nr "fno-omit-frame-pointer" app/
Binary file app/dpdk-procinfo matches
Binary file app/testpmd matches
Binary file app/dpdk-test-eventdev matches
Binary file app/dpdk-test-crypto-perf matches
Binary file app/dpdk-pdump matches
# grep -nr "fno-omit-frame-pointer" kmod/
<confirming application are shared library, hence code segment should not have
been built with these flags>
# ldd x86_64-native-linuxapp-gcc/app/* | grep rte_eal
librte_eal.so.5.1 =>
/home/saesrv02/Downloads/dpdksrc/dpdk-17.08/x86_64-native-linuxapp-gcc/lib/librte_eal.so.5.1
(0x00007f9a7badc000)
librte_eal.so.5.1 =>
/home/saesrv02/Downloads/dpdksrc/dpdk-17.08/x86_64-native-linuxapp-gcc/lib/librte_eal.so.5.1
(0x00007fb2fb318000)
librte_eal.so.5.1 =>
/home/saesrv02/Downloads/dpdksrc/dpdk-17.08/x86_64-native-linuxapp-gcc/lib/librte_eal.so.5.1
(0x00007f865530f000)
librte_eal.so.5.1 =>
/home/saesrv02/Downloads/dpdksrc/dpdk-17.08/x86_64-native-linuxapp-gcc/lib/librte_eal.so.5.1
(0x00007f83c7c4c000)
librte_eal.so.5.1 =>
/home/saesrv02/Downloads/dpdksrc/dpdk-17.08/x86_64-native-linuxapp-gcc/lib/librte_eal.so.5.1
(0x00007f1003c10000)
If you really want to take environment value into account, you can just comment
this assignment or use ?= operator.
Answer> I also tried adding variable into ".config" -
"CONFIG_RTE_TOOLCHAIN_GCC_DEBUG=y", then manually editing
"mk/toolchain/gcc/rte.vars.mk" as "ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC_DEBUG),y)
TOOLCHAIN_CFLAGS ?= <my desired flags>". But this requires to edit or sed the
file for each new combination. Hence dropped this approach.
Note that you can also use EXTRA_CFLAGS.
Answer> As per the mailing list
http://dpdk.org/ml/archives/dev/2015-August/022592.html, passing EXTRA_CFLAGS
will solve the issue. But this affect modules, libraries and application
grep -nr EXTRA_CFLAGS * --include=*.mk
internal/rte.compile-pre.mk:78: $(CFLAGS_$(@)) $(HOST_EXTRA_CPPFLAGS)
$(HOST_EXTRA_CFLAGS) -o $@ -c $<
internal/rte.compile-pre.mk:83: $(CFLAGS_$(@)) $(EXTRA_CPPFLAGS)
$(EXTRA_CFLAGS) -o $@ -c $<
rte.app.mk:245:O_TO_EXE = $(CC) -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $(OBJS-y)
$(call linkerprefix, \
rte.bsdmodule.mk:34:override EXTRA_CFLAGS = $(MODULE_CFLAGS)
$(EXTRA_KERNEL_CFLAGS)
rte.cpuflags.mk:36:AUTO_CPUFLAGS := $(shell $(CC) $(MACHINE_CFLAGS)
$(WERROR_FLAGS) $(EXTRA_CFLAGS) -dM -E - < /dev/null)
rte.lib.mk:80:LD := $(CC) $(CPU_CFLAGS) $(EXTRA_CFLAGS)
rte.module.mk:34:override EXTRA_CFLAGS = $(MODULE_CFLAGS) $(EXTRA_KERNEL_CFLAGS)
toolchain/gcc/rte.vars.mk:69:ifeq (,$(findstring -O0,$(EXTRA_CFLAGS)))
toolchain/gcc/rte.vars.mk:70: $(warning "EXTRA_CFLAGS doesn't contains -O0,
coverage will be inaccurate with optimizations enabled")
I would be in favor of removing these variables.
We have too many variables.
Answer> Ok, at least we should have right variables to allow build components
with right settings.
Thanks
Vipin Varghese
-----Original Message-----
From: Thomas Monjalon [mailto:[email protected]]
Sent: Tuesday, November 7, 2017 2:38 AM
To: Hunt, David <[email protected]>; Varghese, Vipin
<[email protected]>
Cc: [email protected]; Richardson, Bruce <[email protected]>
Subject: Re: [dpdk-dev] [PATCH v1] mk: allow use of toolchain cflags
03/11/2017 10:40, David Hunt:
> From: Vipin Varghese <[email protected]>
>
> with 'export TOOLCHAIN_CFLAGS' the values are not inherited throuhout
> make system. The change appends the user defined cflags.
Why do you want to use export from the shell environment?
The standard way of overriding a variable with make, is to specify a value on
the make command line.
[...]
> -TOOLCHAIN_ASFLAGS =
> -TOOLCHAIN_CFLAGS =
> -TOOLCHAIN_LDFLAGS =
> +TOOLCHAIN_ASFLAGS +=
> +TOOLCHAIN_CFLAGS +=
> +TOOLCHAIN_LDFLAGS +=
There is nothing to append here.
It is here only for documentation purpose.
If you really want to take environment value into account, you can just comment
this assignment or use ?= operator.
Note that you can also use EXTRA_CFLAGS.
I would be in favor of removing these variables.
We have too many variables.
