[U-Boot] [PATCH v2 4/5] env: Allow environment files to use the C preprocessor
Stephen Warren
swarren at wwwdotorg.org
Wed Jun 26 22:05:15 CEST 2013
On 06/24/2013 02:46 PM, Simon Glass wrote:
> In many cases environment variables need access to the U-Boot CONFIG
> variables to select different options. Enable this so that the environment
> scripts can be as useful as the ones currently in the board config files.
The addition of += seems like a separate change to enabling
pre-processing, but I guess they're both simple enough and this is a new
features, perhaps it's not a big deal.
> diff --git a/Makefile b/Makefile
> $(obj)include/generated/environment.in: $(obj)include/generated/autoconf.mk.base \
> $(wildcard $(ENV_FILE))
> if [ -f "$(ENV_FILE)" ]; then \
> - cat $(ENV_FILE) >$@ ; \
> + $(CPP) -P $(CFLAGS) -x assembler-with-cpp -D__ASSEMBLY__ \
> + -include $(obj)include/config.h $(ENV_FILE) -o $@; \
I guess -undef doesn't make sense here, since config.h could well rely
on standard pre-defined macros.
Does it make sense to -D __UBOOT_CONFIG__ rather than, or in addition
to, -D __ASSEMBLY__ here, so headers can tell what they're being
included for? The series I sent for dtc+cpp did -D __DTS__ for similar
reasons.
> diff --git a/tools/scripts/env2string.awk b/tools/scripts/env2string.awk
> + # Deal with +=
> + if (match(var, "(.*)[+]$", var_arr)) {
> + var = var_arr[1]
> + env = vars[var] env
> + }
Does this work if you write just:
foo+=bar
rather than:
foo=
foo+=bar
It might be worth allowing the former syntax, so you don't need to
explicitly assign empty values before a sequence of ifdef'd +=
operations. If the above blows up, at least a descriptive error message
might be useful.
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